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The 9 June 1995 issue of Science has a rare (perhaps unique) mycological cover. Equally unusual, the fungus being shown is Lecanora dispersa (Pers.) Sommerf., a crustose lichen, one of those fungi that are models of symbosis but get only passing mention in mycology courses. This exceptional cover signals a paper by A. Gargas, P. T. DePriest, M. Grube & A. Tehler entitled "Multiple origins of lichen symbioses in fungi suggested by SSU rDNA phylogeny" (vol. 268, pp. 1492-1495). By studying 10 mycobionts and 65 other fungi using small subunit ribosomal DNA the authors determined the relationship of the 10 lichen species to the other fungi. They found that there were at least five independent origins of the lichen habit in disparate groups of ascomycetes and basidiomycetes; two and three occurrences, respectively. In the ascomycetes, species in the Lecanorales, which form haustorial connections with Trebouxia, appeared to occupy the most basal origin: Lecanora dispersa (Pers.) Sommerf., Lecidea crustulata (Ach.) Spreng. [as Porpidia] and Sphaerophorus globosus (Huds.) Vain. The other group of ascolichen species are in the Arthoniales whose phycobiont is frequently Trentepohlia: Arthonia radiata (Pers.) Ach., Dendrographa leucophaea (Tuck.) Darb., Lecanactis abietina (Ehrh.) Körb., and Schismatomma pericleum (Ach.) Br. They also predict finding the acquisition of the lichen habit in other lineages, particularly the Dothideales, Graphidiales, Ostropales, and Pyrenulales.
Within the basidiolichens the basal position was occupied by a few species of Multiclavula that form loose associations with Coccomyxa or occasionally with cyanobacteria. The other two lineages were formed by independent examples: Omphalina ericetorum (Fr.) M.Lange [as O. umbellifera (Fr.) Kummer], which, on the cladogram, appeared to be closely allied with Agaricus bisporus (J.Lange) Imbach and Pleurotus ostreatus (Jacq.) Kummer, and Dictyonema pavonia (Sw.) Parb., which appeared to be closely allied to Athelia bombacina Pers. and Schizophyllum commune Fr.
The paper is illustrated by a cladogram [Fig. 1] showing all the included species and coloured photographs showing a representative of each of the five lichen lineages. (The key to the colour coding in the dendrogram, omitted in the original article but included in the reprint, is as follows: lichen formers - green; mycorrhizal species - pink; plant pathogens - blue; animal pathogens - orange; saprobes - black.)
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Aspergillus fumigatus Fresenius and similar filamentous fungi are usually harmless but can cause havoc in immunocompromised patients whose immune systems have been weakened or destroyed by chemotheropy or HIV. These species are retarded, but not killed, by established antifungal drugs. TheNew Scientist (9 December 1995, p.20) reports on a fungicide produced by Streptoverticillium fervens (De Boer, Dietz, Evans & Michaels) Locci, Baldacci & Paetrolini Baldan, a soil actinomycete (cited as a fungus), that is harmless to mammals.
Though discovered in 1989 by Fujisawa, a Japanese pharaceutical company, it has only now been synthesised -- by Tony Barret and Krista Kasdorf of Imperial College. The metabalite is composed of a chain of five carbon triangles (cyclopropyls), causing it to be dubbed "jawsamycin" because of the resemblance to shark's teeth. The compound, however, has 10 chiral centres, points about which mirror images of the molecule can form for a total of 1024 possible isomers, only one of which is jawsamycin. The Imperial College chemists will report how they synthesised a precise replica of the natural product in 15 chemical reactions in a future issue of Chemical Communications; a synopsis of the synthesis is described in this report.
Vesicular arbuscular (VA) mycorrhizae are associated with most terrestrial plants, including a number of major crop species. At present the molecular mechanisms underlying fungal-mediated uptake and translocation of phosphate from soil to plant remain unknown because these fungi are obligate symbionts. Reports in Nature 378 (1995) 560-561; 626-629 describe how M. J. Harrison and M. L. van Buuren, studying Glomus versiforme (Karst.) Berch, have begun to investigate this process by being the first to identify and clone a complementary DNA that encodes a transmembrane phosphate transporter (GvPT). Expression of GvPT was found to be localized to the external hyphae which are the initial site of phosphate uptake from the soil.
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Mushrooms can, it seems, be very ancient and very large. Hibbett, Grimaldi, & Donoghue in a short article in Nature (377, 1995, p. 487) describe "Cretaceous mushrooms in amber" from New Jersey that are 90-94 million years old, three times the age of Coprinites dominicana, dated at 25-30 million years (references in their report). Although this material is the most ancient for a mushroom, the oldest hymenomycete fossil is that of Phellinites digiustoi, an apparently perennial polypore from the Jurassic. The unnamed New Jersey material is illustrated by light and scanning electron micrographs and an interpretive drawing. The authors say the specimens bear a strong resemblance to the contemporary genera Marasmius and Marasmiellus, common and widespread decayers of leaf litter and wood, and that amber pieces from the site contained bark fibres and leaves of a species of the Cupressaceae. They state that this new fossil find provides "... another calibration point for basidiomycete molecular clocks." which estimate the radiation of the homobasidiomycetes to have started about 200 mya (million years ago).
Several years ago Smith, Bruhn, & Anderson reported in Nature (356, 1992, pp. 428-431) that "The fungus Armillaria bulbosa is among the largest and oldest living organisms." Knowing the age of a mycelium in a culture dish is one thing, determining that of, say, a fairy ring is quite another. In the past such determinations relied on two criteria: assay of somatic interactions and distribution of mating-type alleles. The first [e.g., studies by Alan Rayner] inferred genetic dissimilarity when an 'antagonistic' reaction line developed along a contact zone between different mycelia; the latter depended on the assumption that fruit bodies with the same alleles at A and B loci and growing in 'reasonable' proximity were from the same dikaryotic mycelium. Unfortunately, however, neither procedure can distinguish a single large clone from a number of closely related individuals. To overcome these difficulties the authors used molecular methods: "To discriminate clearly between vegetative growth of an individual and multiple matings involving similar genotypes [by] examin[ing] allelic composition at heterozygous loci marked by restriction fragment length polymorphisms (RFLPs) and random amplified polymorphic DNAs (RAPDs) ...." From this analysis they determined that a mycelium of Armillaria bulbosa (Barla) Kile & Watling (Intersterility Group VII; see Motta, Mycologia, 78 (1986), pp.471-474) occurring in a permanent study site in a northern Michigan (USA) hardwood forest was the world's largest organism, that it occupied a minimum of 15 hectares, weighed in excess of 10,000 kg, and had remained genetically stable for more than 1,500 years.
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Reports of benevolent and prophylactic plant/fungal interactions have appeared in New Scientist. The "Fungi stand guard at the grass roots" report, 16Mar(1996), p.20, presents a summary of two papers by British and Canadian ecologists in the Journal of Ecology (Tables of Contents can be viewed at
Roots are also the subject in the second New Scientist account. In "Sticky coat stops crop rot", 10Feb(1996), p. 19, progress is reported in protectively coating crop seeds with sticky solutions of certain forms of bacteria. Bacteria, grown in fermenters, are mixed with water and methyl cellulose to form a viscous solution used to coat seeds; after germination they colonize the developing root system, producing antifungal compounds throughout the growing season. Wheat plants are being protected from take-all disease, caused by Gaeumannomyces graminis (Sacc.) von Arx & Olivier var. tritici Walker, by coating their seeds with mixtures of strains of the common soil bacterium Pseudomonas fluorescens which produce fungicides, e.g., phenazine-1-carboxylate. Fungicidal strains of other bacteria have also been found that protect against root rots caused by Pythium and Rhizoctonia solani Kühn.
This issue notes reports of fungal malevalance. A paper by Lee et al. (Chemistry & Biology 2: 721-727; 1995) descrsibes "The relationship between an endangered North American tree and an endophytic fungus". The tree is the Florida torreya (Torreya taxifolia) and the fungus is Pestalotiopsis microspora (Speg.) Batista & Peres. The tree, endemic to ravine slopes along the Apalachicola River in Northern Florida and adjacent Georgia, has become the rarest wild tree in North America after a catastrophic decline in the late 1950's. The problem is not the fungus per se, which resides in the inner bark of both disease free and affected plants, but is a consequence of physiological or environmental factors that apparently trigger its pathological activities. Under these conditions, confirmed in pure cultures, the fungus produces the phytotoxins pestalopyrone, hydroxypetalopyrone, and pestaloside which give rise to the disease. Further, pestaloside also has antifungal activity which may reduce competition from other fungal endophytes within the host.
Karnal bunt, Neovossia indica (Mitra) Mundkur, was responsible for a major drop in the prices of the March contract for US wheat futures (International Herald Tribune, 11 March 1996). An outbreak of this rare disease caused Department of Agriculture officials to quaranine about 20,000 acres (8094 hectares) of Arizona durum wheat and block its shipment to 21 countries, including Algeria, Brazil, and China that are among America's largest buyers. The disease is nontoxic but imparts a fishy smell that reduces the value of the wheat.
Rhizopus microsporus van Tieghem caused four infections (two lethal) at the Birmingham Women's Healthcare Trust (The Guardian, London, 1 May 1996). Wooden tongue depressors, used to immobolize the arms of premature babies where life support tubes were inserted, became contaminated and the fungus damaged blood vessels, causing the blood supply around the infant's body to become blocked. Plastic spatulas are now being used instead.
At the May New Orleans meeting of the American Society for Microbiology, Dr. Leoncio Garza-Valdes, one of a team from the University of Texas Health Science Center, San Antonio, reported that a microscopic layer of bacteria and fungi may have thrown off the carbon dating of the Shroud of Turin and all other ancient fabrics by hundreds, even thousands, of years, according to the International Herald Tribune, 22 May 1996. Asked for further information Garza-Valdes replied that the fungi were species of Acremonium, Aspergillus, and Cladosporium and that the microorganisms deposited exopolymers on the surface of the flax fibres, producing an acrylic-like coating that he calls a bioplastic.
GRIST WANTED. Dispatches started as, and continues to be, a round up of general interest reports of fungi from a variety of publications seen by the author -- newspapers, general magazines, and trade and professional journals. I'm sure such reports also occur in similar publications around the world. If you, our readers, find such an item in your reading I would appreciate being sent a copy or synopsis of it (and if from a non-English source, please, provide a translation) and also be sure to note its source, pagination, date, etc. All material sent in and used will be duly acknowledged.
Two economic items. P. H. Abelson in an editorial in Science 266 (1994), p. 1303, entitled "Adequate supplies of fruits and vegetables", observes that, on the one hand, there is an increasing public awareness that a diet with four or five fruits or vegetables per day can substantially reduce the incidence of many types of cancers while, on the other, there is a trend toward the reduction or prohibition of fungicides, which could lead to food scarcities. He notes the prohibitive cost of developing new fungicides -- a candidate commercial product is subjected to a battery of about 100 different tests that can take as long as nine years and cost $50 to $100 million, and that fungi would destroy crops if there was a reduction of permissible fungicides to a few; captan, a relatively non-toxic, widely used fungicide that's scheduled to be discontinued, is specifically mentioned. The figures Ableson cites for crop reduction if synthetic fungicides were not available are: apples - 40%, grapes - 33%, peaches - 49%, and strawberries - 38%.
The other report, entitled "Fatal fungus ravages vineyards", appears in New Scientist, 19 October 1996, and describes the devestating effects Eutypa armeniacae Hansford & Carter is having on Cabernet, Sauvignon, Cinsault, and Ugni blanc grapes of prestigious French crus. The fungus enters through open wounds (pruning, in particular), develops a canker, and spreads through, and plugs, the xylem, causing the vine to wither and die. The symptoms are not obvious and can disappear for several years at a time. The reasons they are so erratic is that they only develop when a mycotoxin, eutypine, is produced and rises through the xylem. It is hoped that the recent identifcation of the toxin will lead to genetically engineered vines that are disease resistant. (A report by Roustand & Follot is to appear in a future issue of the Journal of Plant Physiology).
Yeasts and yeastlike fungi are prominent in the very scientific literature. Here, however, are some items of more general interest. From the popular press there is a general awareness of the human genome programme and of similar mapping programmes for other key organisms. Of these, Saccharomyces cerevisiae Meyen ex E. C. Hansen is the first eukaryote to be completely sequenced. This achievement is highlighted in last July's Trends in Genetics (vol. 12, No. 7) in a cover issue largely given over to articles on "The yeast genome sequence". Bernard Dujon, pp. 263-270, provides an excellent summary entitled "The yeast genome project: what did we learn?" Four years ago yeast chromosome III was the first eukaryotic chromosome ever to be sequenced with most of the proteincoding genes not corresponding to any previously encountered sequence; in the now completed total sequence a significant proportion of the genes, approximately 2000, are still orphans of unpredictable function. These, in the author's opinion, warrant the utmost priority for future investigation.
On a lighter note is a report on mummy's beer in Science (1996, 273, p. 432) entitled "How the ancient Egyptians brewed beer". Historians have widely believed that beer was made by crumbling bread into water, followed by fermentation of the resulting liquid, but when Delwen Samuel, a Cambridge University archaeologist, tried the idea she found it didn't work. She therefore used scanning electron microscopy to examine starch granules recovered from ancient tombs. Processed starch granules can change in three ways: 1) when exposed to limited amounts of water (e.g., modern baking), they swell but retain their integrity; 2) when heated in water they swell and fuse together; 3) malting (e.g., modern brewing), causes them to become pitted as enzymes change the starch into sugars. Her SEM images were of the third type and she concluded that the ancient Egyptians carried out a two-step process in which grains were first malted and heated to provide sugars and flavour, then were mixed with sprouted grains in unheated water; the resulting sugar and starch solution was then decanted and fermented to make the beer. The research was sponsored by the Sottish and Newcastle brewery and a group there, lead by James Merrington, was able to make a batch of beer using Samuel's process and contemporary ingredients (emmer wheat flavoured with coriander and juniper). The result was a delicious beer with a long, complex aftertaste. Unfortunately, it was a one off trial. The full text of Samuel's report is presented in a paper (pp. 488-490 in the same issue) entitled "Investigation of ancient Egyptian baking and brewing methods by correlative microscopy".
Staying with brewing, there is an account in New Scientist reporting "Fermenting faster pints" (20 Nov 1996, p. 23). Lagers, unlike most British beers, normally undergo a secondary fermentation to produce the lager's characteristic flavour and appearance. Although lagers conventionally take two to four weeks to mature, Eric Booremans, Alfa Laval Brewery Systems, Belgium, has developed a technique that uses a specially designed glass reactor containing small pellets of yeast distributed on a carrier of sintered glass that increases the surface area of yeast presented to the liquid. In this reactor, demonstrated last November at the Brau Exhibition in Nuremburg, lager takes only two hours to mature.
Another New Scientist (28 Sep 1996, p. 19) report has the beguiling title "Meet your cousin, the mushroom". It is an account of the finding of collagen in the fimbrae of the anther smut Microbotryum violaceum (Pers. : Pers.) Deml & Oberw., a ustomycete that is yeastlike in culture. Fimbrae are long, narrow flexuous structures on the cell surface; they are common in fungi and are thought to be involved in such activities as mating and pathogenesis. Collagen, the protein that 'glues' animal bodies together has, until now, been known only from the animal kingdom. The identification included the molecular match of short stretches of amino acids with those known for collagen and the observation that human cells grown with the fungal protein responded in the same was as they do with human collagen. This discovery complements recent genetic evidence that suggests fungi are nearer to animals than to plants. The full report, entitled "Fungal fimbrae are composed of collagen", by Martina Celerin et al. appears in The EMBO Journal 1996, 15, 4445-4453.
A later, complementary report by J. L. Manley & Y. Takagaki, entitled "The end of the message -- another link between yeast and mammals", appeared in Science 274 (1996), pp. 1481-1482, and is a summary of three reports on pp. 1511-1520 of the same issue. These reports present evidence that the protein factors on the 3' end that recognize the poly(A) site on precursor mRNA are conserved between yeast and mammals. The authors observe in their concluding paragraph that: "Polyadenylation now joins the list of cellular processes in which key factors are conserved from yeast to mammals. But like these other processes, there are also differences, many of which undoubtedly reflect the more complex regulatory requirements inherent to multicellular organisms."
With the foray season coming up, the subject is mushrooms. The main items of news is the report last January of the successful cultivation of Cantharellus cibarius Fr. ("Successful cultivation of the golden chanterelle"; Nature 385, p. 303). Eric Danell and Francisco Camacho achieved this long sought goal with an eight year old Swedish isolate grown in pots with 16 months old Pinus sylvestris seedlings (unlike noncommestible, fast growing species such as Laccaria whose spores quickly colonize roots). C. cibarius is a mycorrhizal species and in nature has been found in Sweden with trees older than 25 years. The greenhouse specimens, whose development time from inoculation to fruiting took over a year, were, however, found not to be attached to roots or mycelial cords. The fruiting bodies were normal in size, odour, trama, and spore-forming hymenia and, like wild strains, had great quantities of associated fluorescent Pseudomonas. The authors suggest that the success of their mycelium plus seedling technique for growing Cantharellus could make it possible to study a number of aspects of its biology and life cycle and could also be applicable to growing other edible or endangered species in the green house, such as Tricholoma matsutake. Roy Watling, in an introductory essay in the same issue ("The business of fructification", pp. 299-300), comments on the increasing monetary value of exotic mushrooms as supermarkets stock an increasing diversity of field collected species, the nature of mycorrhizae, and the potential scientific and economic importance that Danell's and Camacho's work has for understanding the link between fungus and host tree. These reports were also noted in New Scientist ("Gourmet mushrooms for all", 25 Jan 1997, p. 6) and included the observation that "The world market for chanterelles is worth some £1 billion a year. All 200 000 tonnes of Cantharellus cibarius are collected from the wild.".
With the foray season just past, several more mushroom items. The Observer (25 August 1996) had a major, large headlined story entitled "Why only the Queen can save the New Forest fungi" with the subline that "Edible mushrooms are being wiped out to flavour Nineties menus in top London restaurants." It reports on the growing feud between the Forestry Commission and other conservationis who are trying preserve the mushrooms in the 1000 square miles of the New Forest (of 60 species surveyed, 20 are in decline and 5 may be extinct) and the increasing hordes commercial and foragers who rampage through it each Autumn taking all before them. The Forestry Commission would like to impose a blanket ban on commercial mushroom collecting in the New Forest but the traders are invoking laws dating back to the Magna Carta to claim immunity. Much of the blame for the increasing depredation is laid to the recent publication of popular books and television programmes on identifying and cooking mushrooms.
New Scientist's inside back cover feature, The Last Word (1 March 1997), had replies to a question asking "What other animals naturally eat fungi?" A reader from Israel commented that in the Middle East one had to get out early to beat the vole Meriones tristrami and the porcupine Hystrix indica. Another response mentioned African termites, stated that reindeer go crazy for Amanita muscaria (L. : Fr.) Hooker, and dealt at length with the scoiology of this mushroom. A third reader noted that on Hampstead Heath only giant puffballs bore the marks of rats, squirels, or birds. A fourth response (12 April 1997) gave related information from a Norwegian newspaper which reported enhanced levels of radiation in sheep and goat meat from some areas of the country that had been affected by the Chernobyl disaster because the animals were eating mushrooms that had taken up radiative elements that had been washed down into the soil below grass level.
The Kerryman (8 November 1996) had a nice feature article entitled "Mushroom spring up in magical ring in Muckross" describing, with an excellent photograph, a large clitocybe fairy ring found in Woodlawn Park, Killarney. The well written and informative report includes the information that púca is the Irish word for fairy, that the puff ball is called cáisc púca (fairy cheese) and that moisarún púca means fairy mushrooms.
Finally, a bit of music to accompany your gourmet meal with exotic mushrooms, fine wine, and candle light: Mussorgsky's "Gathering Mushrooms" sung by Boris Christoff (in the boxed set, Songs, EMI Références mono CHS7 63025-2).
Another cover story. That of the 7 August 1997 issue of Nature has a picture looking up into a tree and across it in large type, the words: "The wood-wide web". The article being highlighted is Simard's et al., "Net transfer of carbon between ectomycorrhizal tree species in the field", vol. 388, pp. 579-582; the authors used "... reciprocal isotope labeling in the field to demonstrate bidirectional carbon transfer between ectomycorrhizal tree species Betula papyrifera and Pseudotsuga menziesii, resulting in net carbon gain by P. menziesii." The significance of this study is described by David Read in the News and Views section, pp. 517-518: "Mycorrhizal fungi - The Ties that Bind". Most ectomycorrhizal fungi, the raison d'être of forays and the growing concern of conservationists, are broad spectrum in their range of host species with the result that roots of trees like birch or Douglas fir can be colonized by many species of fungi which extend hyphae and rhizomorphs from tree to tree. Conequently, in an undisturbed forest ecosystem, most of the trees of whatever species are interconected by diverse populations of mycelia. In these associations of tree and fungal species -- "functional guilds" -- increase of hyphae depends on a supply of photosyntetically fixed carbon from the plant, whose roots, in return, receive essential minerals (particularly, nitrogen and phosporus) extracted by the fungus from the impoverished soil. Most investigations of this complex system have used pot-grown plants or excised roots to study the relationship between the symbiotic partners. Simard et al., however, grew young trees close together in the forest and fed them radio-carbon labelled CO2 and were able, for the first time, to show a net transfer of carbon from birch to fir, both of which shared up to ten mutually compatible mycobionts (transfer did not extend to endomycorhizal cedar). Further, they showed that if the fir were in the shade there was a marked elevation of the carbon it received from the birch; such a sharing could certainly benefit seedlings growing in the dense shade of mature plants. This new information provides quantitative support for Clements's 1918 concept of the community as an 'organism' and indicates that the mycorrhizal wood-wide web can potentially effect an increase in biodiversity by promoting coexistence while reducing the dominance of aggressive species. A major contribution of Simard et al.'s study should be to advance a shift in ecological thinking -- from an emphasis on competition between plants to focusing more on the role of intracommunal distribution of resources.
More information on Mycorrhiza can be found on the BMS Internet site
Finally, this seems an appropriate place to mention the BP Conservation Programme Awards
Traditional Christmas double-issues brought us a good crop. The Economist (1997, 345: 115-118) had a nice article on "Fun with fungi -- Those magical mushrooms" covering mycophagy, mycolatry, and mycoliterature. Of particular note in the first category is the caution about Paxillus involutus (Batsch) Fr., the brown roll-rim, that: "... was considered edible, until 1940, when a German mycologist, Julius Schaeffer, died after eating a succession of roll-rim meals. Nobody had realised that its effect was cumulative, eventually making it lethal." Benjamin (Mushrooms -- poisons and panaceas, pp. 382-384) describes this as immune hemolytic anemia, stating that it "... generally develops in individuals who have eaten [the mushroom] for years with no ill effect. For reasons, presently unclear, a few people produce ... antibodies to an unidentified antigen in the mushroom. During the course of a subsequent meal, antigen-antibody complexes form, aggltination occurs, complement is fixed, and the red blood cells under go intravascular hemolysis. The onset of the symptoms is rapid, developing within two hours of the mushroom meal. ... Some poisonings have proved fatal." A second important reference is Watling's Children and Toxic Fungi: The essential medical guide to fungal poisoning in children, where it is cited as Toxic category VII Gastrointestinal irritants and intolerance. Links to both books can be made from
New Scientist had two items. A note (p. 13) reporting the production of ferulic acid, a UV-blocking ingredient of suncreams presently manufactured chemically, from farm waste. Gary Williamson and his associates at the Institute of Food Research, Norwich, have identified enzymes in common fungi that make ferulic acid from such by products as cereal bran and sugar beet pulp. An e-mail to the IFR elicited a very nice reply from Dr. Craig Faulds. The group is involved in a European Commission-funded project for the fungal bioconversion of ferulic acid from agroindustrial wastes into high value flavour compounds. In the noted research two inducible enzymes, feruloyl esterases, were produced by two strains Aspergillus niger van Tieghem and were able to release 95% of available ferulic acid. The enzyme induced depends on the carbon source. One is particularly good on ferulic acid from wheat bran when used in conjunction with a xylanase from Trichoderma viride Persoon : Fries; the other acts on feruloyl groups found in pectins and is produced when the fungus is grown on sugarbeet pulp.
Second is an article on esca by Lewis Perdue & Lucie Morton ("A mouldy old vintage", pp. 40-41). Esca is a disease that turns the normally clear sap of grape vines into a molasses-like 'black goo'. In the temperate climates of continental Europe, New Zealand, and South Africa death may be prolonged, but in the extreme temperatures of California and Australia the disease can kill a seemingly healthy plant within hours. The first signs of disease are stunted growth, yellowing, and curling leaves; symptoms that mirror other vine disorders. The goo is organism free, made up of phenolic compounds, and is apparently a direct response of the the xylem system which carries water and nourishment up from the roots to the stem, foliage, and fruit. The cause of the disease, also called Black Measles, may not be caused by a single fungus. It has been attributed to Phialophora parasitica Ajello et al.which has recently been transferred to Phaeoacromonium (Crous et al.,Mycologia 88, 1996, 786-796). Cylindrocarpon obtusisporum (Cke & Harkn.) Wollenweber is also mentioned. A review of the disease by Luis Mugnai's group (University of Florence) will soon appear in Plant Disease. [A different xylem disease of grapes was reported in the 11(1) Mycological Dispatches.]
Some smaller items. 'The rot sets in -- To keep forests healthy, trees must suffer a little', New Scientist 1 November 1997, p. 12, describes how parasitic fungi are helping to rehabilitate ailing forest ecosystems. While sick and dying trees provide habitats for birds, mammals, and reptiles they are usually harvested by US loggers at the first symptoms of infection for pulp with the dual consequences of very health stands with no places of shelter. In the past, forest managers have artificially damaged trees by blasting off their tops or burning their roots but such trees were not particularly attractive to animals and the injured trees survived for only a few years. The solution adopted was to saturate wooden dowels in liquid cultures of Phellinus pini (Brotero : Fries) Ames and Fomitopsis pinicola (Swartz : Fries) Karsten, normal heart rotters of western larch,and insert them into holes bored into the centres of selected trees in Oregon's Winema Natural Forest. Of 60 trees inoculated two years ago all became infected and ten are already hosting woodpeckers (about double the rate found in blasted trees). A further advantage of the technique is that the fungi attack only the heartwood and do not impede growth, so the trees should provide habitats for forest denizens for numbers of years.
On the other hand, New Scientist also reports that 'Hardy elms fend off killer fungus' (28 September 1996, p. 13). A twenty year breeding programme by the US National Arboretum, Glendale, Maryland, has succeded in developing two strains of the American elm -- 'Valley Forge' and 'New Harmony' -- that are resistant to Ophiostoma ulmi (Buisman) Nannfeldt, Dutch elm disease which is spread by the elm bark beetle.
The 26 June 1997 front page of the Daily Telegraph had a front page report by Robert Uhllg entitled 'Enzyme washes away peril of the rogue red sock', describing an enzyme from Coprinus that removes non-fast dyes that have bled into the wash water. It was discovered by Anders Pedersen, Novo Nordisk, who found that it is more efficient than any of the known polymers contained in some soap powders: when mixed with hydrogen peroxide and an organic compound called phenothiazine-10-propionic acid it creates a detergent that bleaches any lose dye in the water and cleans clothes that may have taken up some of the dye. If it works it will be a great boon, particularly as there isn't at present any product that counteracts escaped dye from affecting other clothes, specificly such fabrics as nylon that once dyed are permanently coloured.
'Deadly Damp' (New Scientist 9 August 1997, p. 10) reports on a cluster of infant deaths from bleeding of the lungs (pulmonary haemosiderosis) in Cleveland, Ohio. Normally a very rare condition, invesigators from the Case Western Reserve (Cleveland) found that all the homes concerned had been severely water damaged in one way or another and that they all had growths of a black mould, Stachybotys chartarum (Ehrenberg) Hughes [=S. atra Corda]. In Europe it is known that this fungus causes internal bleeding in farm animals when it contaminates their feed and, similarly, it is thought that when the American babies inhaled the spores, which do not grow in the lungs, a toxin they contain (trichothecene) inhibited the production of proteins which, in turn, may have resulted in the blood vessels lining the rapidly growing lungs becoming unusually fragile; a second insult, such as secondhand cigarette smoke, caused the the capillaries to break.
Fungi to the rescue. In western films we are are familar with the code that the good guys wear white hats; in the fungi it is the white rot basidiomycetes. These species have evolved the ability to degrade lignin and this ability, it transpires, includes a much larger repertoire. An article in Chemistry & Industry (16 February 1998, pp 134-137) by C.E. Evans & C. Bkucke entitled 'Bioremediation by fungi' looks at how fungi are providing rich rewards in the clean up of contaminated waste sites and are helping prevent pollution.
Lignin-like compounds, characterised as recalcitrant because they are difficult to biodegrade and consequently persist indefinitely in the environment, include chlorinated phenols, polychlorinated biphenyls (PCBs), DDT, dioxins, polyaromatic hydrocarbons (PAHs), and nitrotoluenes. These substances have, however, been degraded by white-rot fungi in the laboratory. So far this knowledge has been applied mostly to water effluents (liquid fermentation systems); solid systems such as soil have received less attention because they are more difficult to study. However, Phanerochaete chrysosporium Birdsall and P. sordida (Karsten) J. Eriksson & Ryvarden grown on wood chips and mixed into soil of a disused timber yard heavily impregnated with pentachlorophenol (PCP) wood preservative reduced the contamination by 80% after a month. Phlebia radiata Fries and P. chrysosporium were found to degrade TNT (2,4,6-trinitrotolune), which had acculated at military sites from use of explosives, into less explosive aminodinitrotoluene; unfortunately, though, azo (azoxy) residues resulting from reactions with humus fractions in the soil were as mutagenic and toxic as TNT. Two non-lignolytic enzymes of Pleurotus ostreatus (Jaccquin ex Fries) Kummer), epoxide hydrolase and a cytochrome P-450 monooxygenase, are capable of initiating oxidation of the PAH phenathrene.
Cyanide, another very dangerous waste material, occuring in residues from electroplating plants and coal-fueled town gas facilities, can be degraded by Stemphylium loti Graham, Fusarium lateritium Nees and F. solani (Martius) Sacc. in alkaline conditions. ICI's CYCLEAR, an immobilised enzyme product containing cyanide hydratase from F. lateritium, can degrade 5000ppm of cyanide in liquid waste to <10ppm in 6 hr at ph 8-8.5.
Pollution intervention. A number of enzymes from fungi such as Aspergillus and Trichoderma are being used to pretreat animal feeds to make them more digestable which both increases the feed conversion ratio and results in less agricultural slurry. Paper mills in several countries are using xylanases from selected Aspergillus spp. to break the chemical bonds between lignin and the hemicellulose chains to make more efficient use of the wood pulp.
Returning to ancient Egypt. An earlier column (Mycologist 11/1997, p 87) included a report on pharaonic beer. Here the subject is the ultimate plague described in the book of Exodus and which may have had a mycological cause. The Ten Plagues of Egypt, aired last year (4 August) on Equinox (Channel 4, UK ), presented a coherent chain of events for these disasters based on J. S. Marr & C. D. Malloy's epidemiologic analysis (Caduceus 12/1996, pp 7-24). Plague 1, a river of blood, may have been a red-tide caused by the fresh water dinoflagellate Pfiesteria that secretes a strong neurotoxin that stuns fish and allows the algae to feed on them. The resulting massive fish kill would have markedly reduced the predation on amphibian eggs leading to Plague 2, 'tsefardea'. This biblical term is usually translated as 'frogs' but applies equally, and more probably, to toads (Bufo ) which are far more prolific than frogs. The huge population from this spawning was unsustainable and its collapse led to an explosion of insect populations and Plagues 3, 'chinnim', usually translated as 'lice' but, a 1000 years prior to Aristotle's classification of insects, more probably the biting midge, Culicoides canithorax and 4, swarms of flies, suggested to be the stable fly Stomoxydinae which bites both humans and animals. Plague 5, the murrain of cattle and other domestic animals, may have been caused by two closely related viruses whose vector is the Culicoides midge: respectively, African horse sickness and blue tongue of ruminants. Glanders, caused by Pseudomonas mallei and transmitted by the stable fly, is the suggested cause for Plague 6, boils and blains. Plague 7, violent hail storms, further damaged Egyptian crops already reduced by the unavailability of the Nile's waters due to the first plague. Plague 8, locusts, which arrived soon after the hail, were most likely swarms of the desert locust, Schistocerca gregaria, which appears on various friezes that predate the presumed time of these plagues. The urgent need to save from these hordes what remained of their reduced crops would have caused the Egyptians to hurriedly store them in sheltered granaries and underground storage areas. Plague 9, three days of darkness, may have been a result of a khansin, a frequently occurring, hot southerly wind that can produce fierce sand storms off the Sahara lasting two or three days; and which would also have blanketed the storage sites.
Plague 10, "And all the firstborn ... shall die, from [that] of Pharaoh ... [to that] of the maid servant ...; and [even] the firstborn of beasts.", was the most devastating and historically consequential and is the hardest to explain. Marr and Malloy rule out a natural disaster, such as an earthquake, or a slow-acting infectious disease, such as typhoid, and postulate instead a mycotoxin. Stachybotrys atra Corda [Stachybotrys chartarum (Ehrenberg) S.Hughes] from locust faeces in the undried stored grain -- barley, emmer, and spelt -- would have thrived in the warm, humid conditons of the sand buried stores and would have produced such toxins as macrocyclic trichothecenes which, in very small amounts, can cause illness and death and, in larger quantities, can very quickly lead to massive internal bleeding in the lungs or gastrointestinal track, leading to sudden death. Unwittingly, it is further postulated, it was the strongest, generally the eldest, of both humans and animals that got first and often double rations of the limited and contaminated supplies.
The enslaved Jews were spared most of this fateful concatenation of events, especially the last, because they were restricted to the Nile delta.
An excellently illustrated and referenced booklet is available for £4.00 from: Channel 4, Ten Plagues, PO Box 4000, Manchester M60 3LL; ISBN 1-85144-227-8. It also gives contemporary examples for the postulated causes of each plague. For Plague 10 the example is a series of 33 mysterious child deaths in Cleveland, Ohio, diagnosed as a rare lung disease, pulmonary haemosclerosis. The children lived in damp, poorly ventilated basements in deteriorating buildings; the cause was traced to toxic conidia inhaled by the victims and produced by the black mould, S. chartarum, flourishing on, in this case, the water saturated cellulose of decaying wood and wallpaper.
New world leaf-cutting ants of tropical and subtropical America maintain fungal monoculture (1) as their only food source (2). The mycosymbionts (1) have been identified as Leucoagaricus gongylophorus (Møller) Singer (anamorph Attamyces bromatificus Kreisel, characterized by clumps of gongylidia (2). An evolutionary result of this symbiosis, dated to the early Tertiary (>50 million years ago (2)), has been the loss by the ants of their own digestive enzymes and the consequent dependance on the enzymes of their fungi for the production of low molecular weight, absorbable nutrients (2).
Greater insights into the phylogenetic relationships among the more than 200 known extant species of attine ants, their fungal mycobionts, and the free-living relatives of the latter are provided by a recent Report (2) in Science and its anthropocentric Perspective (4). The fungi of most attine ants (3) are propagated as mycelium, except those maintained as yeasts, by a group of Cyphomyrmex ants. The great majority of these fungi, including the yeasts, are members of the tribe Leucocoprini (Lepiotaceae), a large, poorly known group of predominantly tropical mushrooms; (the only exception is the cultivation of a nonlepiotaceous species by some Apterostigma ants).
The phylogenetic origins of this symbiosis have been ambiguous because of the uncertainty of the possible relationships within the symbiosis (3). In their study Mueller and his associates (5) collected 309 wild basidiocarps (most of those from Panama are undescribed) and 553 isolates of mycosymbionts maintained by seven genera of primitive attine ants (these are most likely to have retained the least modified forms of the ancestral cultivation behavior): 337 from sympatric Panamanian colonies and 216 from colonies along a United States to Brazil transect. The evolution of this symbiosis was inferred from phylogenetic and population-genetic patterns. A dendrogram of the rDNA analyses summarizes data for 57 mycobionts of the seven genera of fungus-growing ants and 36 free-living Lepiotaceae and indicates the presence of at least five clades of ant-fungi, suggesting at least five independent symbiont acquisition events. A close correlatison between two of the unidentified mushroom species and two respective sets of mycobionts, one of which is all the yeast forms, indicates two recent domestication events. The three additional lineagages are statistically distinct.
North (1) also provides an excellent general diagram showing the interactions between these of ants and the fungi they cultivate.
By the time you read this the Natural History Museum (London) should have its leafcutter ant colony established in the Insect gallery
REFERENCES
(1) North, R. (1998) Biologist 45: 199-202.
(2) Fisher, P.J. et al. 1994. Mycologist 8: 128-131.
(3) Hinkle, G. et al. (1994) Science 266: 1695-1697.
(4) Diamond, J. (1998) Science 281: 1974-1975.
(5) Mueller, G. et al. (1998) Science 281: 2034-2038.
Four small items. An article by Steve Connor in The Independent (29 June 1998; Home News, p 11) entitled 'Britons wage war on opium crops' reports on how a virulent strain of Pleospora papaveracea (de Notaris) Sacc., isolated by scientists at the Tashkent Institute of Genetics, destroys opium poppies by causing, it is said, the plant to erupt in lesions. This results in a rapid spread of fungal spores and the decimation of the whole crop. British experts were said to be advising Uzbekistan on how to culture the fungus in batch quantities using industrial fermentors.
Arlette Bataille, in NIFG News [the Northern Ireland Fungus Group newsletter] no. 3, February 1999, comments that "Sweet Chestnut Castanea sativa is one of the dominant woodland species in [Occitan, south of the Loire] which [my father] noticed were dying. The soil-borne phytophthora [P. cinnamoni Rands] root killing disease (ink disease) is probably responsible. Our forays would not alert us since the fungus produces no visible fruiting bodies or mycelium. However a discerning amateur mycologist might spot the soil around the tree that has turned black, hence "ink disease". The fungus often spreads up from the roots to kill tongue-shaped patches of the bark on the lower stem -- a valuable diagnostic feature. Beech (Fagus sylvaticus) is also susceptible. This infection has appeared recently so one can suspect that either the climatic conditions have changed or some other factor has upset the balance for this fungus to destroy trees that have been coppiced over centuries and had remained healthy till lately."
The The Daily Telegraph (20 Feb 1999) had a note headlined "Greenpeace's fungal affinity" which included the following statement: "The material for the [Co-op Bank's credit] cards, which is biodegradable, is made by force-feeding sugar to defenceless and vulnerable fungal spores. The material is known as Biopol, and guess who makes it. Yes, those genetically modified beasts at Monsanto." This, however, is not a case for the 'SPCF' but another sad example of microbial misidentification! The textbook Biology of Microorganisms (7th ed., 1994, p. 670; Prentice Hall) explains that Biopol is a poly-[beta]-hydroxyalkanoate (PHA), a biodegradable polymer synthesized by the bacterium Alcaligenes eutrophus, which "... can be made to overproduce the product and be grown on a large scale [in industrial fermentors] using inexpensive carbon sources such as glucose or ethanol feedstocks." (Parenthetically, the above textbook, p. 847, classifies Allomyces as an oomycete.)
One of William Safire's Language columns in the International Herald Tribune (15 March 1999, entitled 'Taking the litmus test for gambling', had the following statement: "Every Bronx High School of Science graduate knows that litmus is a paper covered with the coloring matter from lichens ...." But I didn't. According to my Webster's Collegiate Dictionary, the word comes from the ON. litmose, lichen used in dying. The Century Dictionary, vol IV, 1902, defines LITMUS as "A peculiar coloring matter procured from Roccella tinctoria and some other lichens. It is prepared chiefly in Holland by macerating the lichens with a mixture of urine, lime, and potash or soda. As a result of the fermentation, the mass finally becomes blue when it is removed, is mixed with calcareous matter to give it consistence, and is then allowed to harden in molds." Any updated and further information will be welcomed.
I've recently subscribed to Plant Talk (P.O. Box 500, Kingston upon Thames, Surrey KT2 5XB, UK) and bought the back issue with Amanita muscaria on the cover (October, 1995). The cover references p 36 -- 100 Plant Facts for Campaigning Conservationists -- an ongoing compendium that, here, provides FACTs 19-30 about Fungi. It's a bit sketchy and interested mycologists might wish to comment on or add to them. Also in this issue, p 14, the following paragraph appears in a report entitled "Potato Blight: an old problem lives on": [T]he fungus that causes Potato Blight, Phytophthora infestans, continues to visit destruction on crops. This summer a new strain of the fungus, believed to have come from Mexico, has swept through the potato fields of Idaho and other western US states. It is feared that this strain may reach Europe. Recently, Swiss agronomists reported a strain of the fungus in their country that was able to reproduce sexually. Potato Blight has been a scourge in Europe for a century and half, apparently on the strength of efficient sexual and parasexual reproduction by the fungus. What may be its potential after a phase of sexual recombination?" For a recent full report see: Duncan, J. 1999. Phytophthora -- an abiding threat to our crops. Microbiology Today 26: 114-116.
A major article in The Daily Telegraph (12 March 1999) entitled "It's just a corker of a controversy", about wine corks vs. plastic closures, had the following statement: "[T]he main issue [is] the little pest at the very root of this dispute. Produced by fungus within the cork, a chemical compound called TCA is responsible for the distinctive mouldy aroma and flavour that renders a wine 'corked' and therefore undrinkable." An e-mail to The Australian Wine Research Institute produced a reply from Dr Paul Henschke which led me to two articles: one by T.H. Lee & R.F. Simpson entitled "Microbiology and chemistry of cork taints in wine" (in G. H. Fleet, ed., Wine Microbiology and Biotechnology, 1993, pp 353-372) identified TCA as 2,4,6-Trichloranisole; Rae Blair, AWRI's Communication and Publicity Manager, also replied, outlining the Institute's extensive research programme on TCA and wine closures. The other reference by N.M. Daly, T.H. Lee & G.H. Fleet entitled "Growth of fungi on wine corks and its contribution to corky taints in wine" (Food Technology in Australia 36, 1984, 22-24) found that the taint ('goût de bouchon') could be imparted by Penicillium granulatum, P. glabrum or two Trichoderma spp. The wine industry is by far and away the largest user of cork. According to Plant Talk 17, April 99, p. 18 "The move to plastic may have a knock-on effect upon the considerable stands of semi-natural oak [Quercus suber ] woodland pasture -- known as 'dehesas' in Spain and 'montados' in Portugal -- across the Iberian Peninsula. ... These open woods on lime-poor soils support plant communities rich in endemics, including scrub, grassland and winter-wet pools, and are home to mammals, reptiles and birds, notably Imperial Eagle and other raptors. Woodland pasture, with well-spaced pollarded trees, is one of Europe's most ancient systems of land management." And what are the fungi of this unique ecosystem?
Hope for 'diabetic' mice and maybe men -- and women -- comes from a species of Pseudomassaria, an ascomycete (Hyponectriaceae), according to a research report by Zhang et al. in Science 284 (1999) 974-977. The strain, ATCC 74411, "... was recovered from leaves of an undetermined plant collection near Kinshasa, Democratic Republic of Congo." Trisha Gura provides the News of the Week synopsis, p. 886, entitled "New lead found to a possible 'Insulin Pill'." The research group, led by Zhang and Moller of Merck's New Jersey laboratory, has found that the fungus produces a unique agent that may lead to a new type of antidiabetes pill that would obviate the need for injections. The group's screening protocol used tissue cultures of hamster ovary cells modified to produce the human insulin receptor. Around 50,000 tests of mixes of synthetic chemicals and natural extracts were carried out before positive results were achieved from an extract prepared from Pseudomassaria culture broth. From the many compounds in this medium, Gino Salituro, a Merck chemist, was able to purify the active agent, a unique insulin mimetic quinone, L-783,281 (dimethylesterriquinone B-1), which stimulated the phosphorylating activity of the cultured insulin receptors by up to 100 times more than the other natural products tested. In not being a protein, like insulin, L-783,281 should be able to withstand digestion if administered orally. When tested on mutant mice with symptoms similar to those of patients afflicted with type 2 (adult onset) diabetes, the results showed a reduction in such symptoms as high blood sugar and defects in insulin production and an enhanced ability to respond to insulin. The report includes a picture of a Pseudomassaria culture on agar, showing its dark orangey-brown colour.
A News Focus report by Virginia Morell in Science 284 (1999) 728-731 asks "Are pathogens felling frogs?". In Australia a massive die-off of more than a dozen species of frogs, including the motorbike frog (so-called from the gear-changing sound of its call) and four species that appear to have become extinct, is being attributed to Batrachochytrum dendrobatidis, a recently described new genus and species identified by Peter Daszak (University of Georgia, Athens). The first die-offs occurred near Brisbane in 1979, perhaps from an introduced infected exotic frog, and from there spread, at a rate of 100 km/yr, throughout the continent.
This virulent fungus is also a prime suspect in the catastrophic pandemic that includes the disappearance of frogs in Panama and Costa Rica, mass die-offs in the United States, and, some epidemiologists believe, may be the key factor in the sudden, mysterious decline of frogs around the globe since 1970. Preliminary genetic studies indicate that only a single species is involved, that it is a newly emerging, highly pathogenic, amphibian disease, and that it is rapidly spreading to new areas worldwide. The infection is believed to start when zoospores invade surface skin cells and then grow by using their keratin. The subsequent cause of death is unknown, but a toxin is suspected.
The 15 May 1999 issue of New Scientist has a brief article entitled "Fiendish Fungus" with the by-line "A hybrid blight is running amok in Europe's Woodlands". It describes a new riparian alder disease that Clive Brasier (Forestry Research, Farnham, UK) and collaborators at the Scottish Crop Research Institute, Invergowie, using DNA sequencing, have determined to be a hybrid between Phytophthora cambivora (Petri) Bisman and a species very similar to P. fragariae Hickman: the first an infection of trees other than alders, the latter a blight of strawberries and raspberries. So far the disease has taken out ~10% of the alders in Wales and southern England, is devastating trees in France, Holland, and Sweden, and is advancing into Germany and Austria.
Further information on the new disease is provided by John Gibbs j.gibbs@forestry.gov.uk and David Lonsdale in a report entitled "Phytophthora disease of alder" in a July 1998 Forestry Authority Information Note (ISBN 0-85538-375-5). The disease mostly affects Alnus glutinosa (common Alder) but has also been found in A. incana (grey alder) and A. cordata (Italian Alder); no other trees have been found to be affected. The disease may start in fine roots which attract the zoospores. Foliar symptoms appear after a stem has been largely girdled after a number of years of infection and are noticeable mid- to late summer because the leaves are abnormally small, yellow, and sparse; they often fall prematurely, leaving the tree bare.
Late blight of potato is the subject of two recent reports and a major web site. The first article, by Jim Duncan, entitled "Phytophthora ( an abiding threat to our crops" (Microbiology Today 26, 1999, pp. 114-116), presents an overview of the disease, caused by P. infestans. The two major sections summarise, respectively, late blight up to 1980 and its status today. The first describes early attempts to create resistant potato varieties (currently, as pointed out in the introduction, the disease costs the US in the order of $3 billion annually while spray control in Europe costs ~£150 per hectare and very much more in tropical highlands). During this period Mexican Scientists, working near the disease's origins in central Mexico found it was heterothallic with mating types: A1 and A2. The oospores have prolonged longevity in the soil.
DNA fingerprinting has established that prior to 1976 the pathogen outside of Mexico was an asexual clone of mating type A1 which as far back as the mid-19th century epiphytotic, including Ireland, had been spread by zoospores during wet weather. The year 1976, however, was hot and dry across Europe and caused major potato crop failures which led to massive imports that brought with them many new strains of P. infestans, including mating type A2 (first recognized by Hans Hohl in 1984). The new sexual population is genetically diverse, more virulent, and has displaced the old population, resulting in earlier and more intense epiphytotics because oospores infect shoots before they emerge from the ground. A new regime of crop rotation etc. is now having to be developed.
The second article by Andy Coghlan entitled "Fighting blight(an artificial gene keeps potatoes disease free" (New Scientist, 11 December 99, p. 8) reports the development by William Kay's research group (University of Victoria, BC) of genetically modified (GM) potatoes resistant to late blight. The team first made a synthetic gene, insrA1, which expresses a hybrid of two antimicrobial peptides: cecropin from the giant silk worm moth and melittin from bee venom. A bacterium was used to insert the gene into Desiree and Russet Burbank potatoes. Although the potatoes made scarcely detectable amounts of the hybrid peptide, their tubers remained healthy despite heavy exposure to a number of pathogens, including P. infestans. As for those people resistant to GM foods, the Victoria group point out that a combination of the same pair of peptides is undergoing clinical trials as a human antibiotic that has shown it has the potential to kill methicillin-resistant Staphylococcus aureus, the infamous hospital 'superbug'.
Finally, Steve Taylor, Vasar College, has created a superb and comprehensive web site entitled "Views of the Famine" composed of a number of files that give contemporary text, figures, and cartoons of the Irish potato blight from The Illustrated London News, The Cork Examiner, The Pictorial Times, and Punch.
Having recently assured a biotechnology post-graduate student that yeasts are fungi, it seems appropriate to devote a column to them. An article entitled "The cell factory, yeast division" by Stéphane Hagan (the European Commission's RTD info, no. 22, May 1999; pp 6-8) uses the term "factory" to refer to the increasing exploitation of yeast natural products as well as other metabolites resulting from genetic modification (GM). Although a number of yeasts manifest a variety of interesting characters, very few have been industrially exploited. Some examples are given of possible utilization. Besides work on S. cerevisiae , GM of other yeasts include Hansenula polymorpha (production of human type-1 collagen) and the red yeast Xanthophyllomyces dendrorhous [Phaffia rhodozyma] (production of large quantities of astaxanthin, a natural pigment in fish, crustaceans, and bird feathers that is used as a food, pharaceutical and cosmetic colouring agent).
The report also reminds us that it was the Eurofan project (134 collaborating laboratories) that achieved the full sequence of 6000 S. cerevisiae genes in 1996 (Mycologist 11, p 87); two years on, a major symposium held in Vlaardingen (NL) in November reviewed the follow-on progress. Two surprises emerged: 1) the discovery that 38% of the genome (>2000 genes) has a completely unknown function and 2) the observation of families of similar, redundant, genes (e.g., more than 200 protein transport genes). The project coordinator, Stephen Oliver, Manchester University, raised the question of why molecular biology has ignored these new genes and opined that new methodologies must be found to identify their functions.
Gene manipulations in Saccharomyces cerevisiae have, on the one hand, resulted in a strain whose glycerol production during fermentation is reduced by 35% thus enhancing ethanol production (global production is currently 30 billion lt/yr and increasing due to its use as an alternative fuel) and, on other, produced a double mutant strain that could help improve the quality of certain wines by producing more (body giving) glycerol and less ethanol and acetic acid (and also making possible new low-alcohol drinks).
The Framework IV symposium is also reviewed in Biologist 47(2000): 15-18 ("Yeast as factory and factotum" by Bernard Dixon). It additionally reports a GM strain of Pichia pastoris that makes human type III collagen; the transfer, from Fusarium solani, of a high-performance, fat-attacking cutinase gene into S. cerevisiae resulting in a strain that produces the enzyme in quantity (utile in washing powders), and the discovery that the system used by yeasts to detect glucose is based on a mechanism very similar to that used by animal cells (which not only provides insights into human physiology but also opens the possibility of developing GM leavening strains for inclusion in frozen dough which will retain much of their fermentation capacity during storage).
GM yeast is also the subject of a report by Debora Mackenzie entitled "Formidable Froth" (New Scientist, 1 April 2000, p 6). Without its top-up foam, the head, a glass of beer looks dead. Formed by a delicate lipophilic, hydrophobic protein coat on the CO2 bubbles as they rise, it is easily dispersed by grease from crisps, lipstick, or less than spotlessly clean glasses. A barley protein formed by the gene LTP1, it is released into the water when sprouts are ground up to make beer; the widely varying amounts, more is made during drier summers and results in more stable heads, is a real problem for brewers. So the gene has been put into brewers yeast with the satisfying result that the yeast secretes so much of the protein that beer would always have a good head.
An early in the year article in The Daily Telegraph entitled "A clever little beast, yeast" by Steve Jones compares the molecular structure of S. cerevisiae with components making up a Mercedes and extracting protein information with fishing: no wonder students and most other people are confused by what yeasts, and fungi, are! It does, however, conclude with a clerihew once pinned to the door of an Edinburgh yeast lab: "Mr Tshombe / Drank Beer made from Schizosaccharomyces pombe. / He said: / When I drink this beer, my legs feel rather queer!".
A New Scientist cover story (24 January 1998, pp 24-28) entitled "Why mad cows are like yeast" reviews the evidence that the non-Mendelian transmission of the traits [URE3] (involved in ureidosuccinate utilization) and [PSI] in S. cerevisiae are carried by prions and that prions are a normal part of yeast cells.
For something completely different see Gary Novak's web page entitled "Morel Mushroom Evolution"
Fungi provided the focus of the well illustrated August 2000 (27, no. 3) issue of Microbiology Today (ISSN 1464-0570) whose cover has a mystery montage of "A selection of [four] British fungi". In the lead essay, "Mycology today", (p 115) Tony Trinci gives a synopsis of what fungi are -- classification, modes of growth, importance to man. He then describes the parlous state of mycology in the UK. He does not believe the problem of the declining number of mycologists "... will be solved by special pleading, but by increasing the quality of research conducted by mycologists ... encompass[ing] modern approaches, including molecular biology, genomics and bioinformatics." He doesn't say, however, where and how such investigators will get the requisite fundamental knowledge in fungal systematics in order to execute such advanced research (a point made by Roy Watling at the start of his article). He concludes by suggesting that one way forward would be to forge stronger links between UK societies concerned with fungi, such as the SGM, BMS, British Society for Plant Pathology, and the British Society for Mycopathology.
In the next article Elio Schaechter describes spore dispersal in "Some wierd and wonderful fungi" (pp 116-117). His first candidate, Puccinia monoica, is a rust of wild mustards (Cruciferae) that causes the host plant to form dense clusters of apical leaves that develop into beautiful yellow, sweet smelling, sticky 'pseudo-flowers'; these deceive pollen-collecting insects into dispersing the spores. He then describes how some insect parasitic fungi, such as Cordyceps and, I would add, Entomophthora, grow slowly within their hosts and, in some inexplicable way, cause the dying insect to climb to the top of a stem to facilitate spore dispersal. He concludes with a section on truffles that includes the example of Tuber gibbosum from Northwestern United States that is the main diet of field voles.
In a technical article entitled "Exploitation of fungal secondary metabolites old and new" (pp 118-120) Geoffrey Turner describes some current applications about how advancing information of fungal gene structure and metabolic pathways is leading to synthesis of new drugs. He points out that "[G]ene isolation and DNA sequencing have revealed a large and growing family of peptide synthetases in fungi and bacteria [and that a]lthough the peptides show a wide range of biological activity, from antibiotics to pathogenicity factors (Table 1), the biosynthetic mechanism is conserved, and the genes responsible are instantly recognized from their modular organization (Fig. 1)." Among the examples he cites are ergotopeptides from Claviceps purpurea, cyclosporin A from Tolypocladium inflatum, aflatoxin from Aspergillus parasiticus. and lovastatin from A. terreus, that has been found to be effective in lowering chloresterol levels in people with dietary problems.
The next two reports concern yeasts: "Brewing yeast selection" by Iain Campbell (pp 122-124) and "Yeast genetics and genomics" by Alan Wheals (pp 126-127).
These are followed by Roy Watling's thoughtful report "Now who would have thought it?" (pp 128-130) about the increasing complex relationships of fungi as revealed by rDNA sequencing data, particularly in such a hotchpotch 'taxon' as the Gasteromycetes. He admits, however, to being " ... at a loss to explain how the padi straw mushroom (Volvariella) sits with the split gills (Schizophyllum) [see cover] and the beefsteak fungus (Fistulina)." He concludes by saying that "The scene is set for an exciting start to the new millennium, the first task being to consolidate these new studies and bring them into the main structure of classification."
This series of reports ends with a medical mycology article entitled "Fungi and skin" by Ruth Ashbee & Glyn Evans (pp 132-134). The authors briefly survey keratinophilic dermatophytes (Tinea or 'ringworm' caused by Trichophyton, Microsporum, and Epidermophyton) and yeast infections. The latter are caused by CandidaMalassezia, e.g., such skin conditions as pityrsiasis versicolor, seborrhoeic dermatitis, and folliculitis). They conclude by stating the compelling need for developing better control of these mycoses, currently costing ~£45.5 million in the UK.
Lastly, there's a brief report towards the back of the issue ("Hawaii 2-0", p 149) about how Clete Kurtzman and his colleagues, using ribosomal 26SrDNA analysis, determined that Pichia hawaiiensis from rotting bark of Charpentiera trees is distinct from the closely related yeasts Pichia populi and Williopsis californica populi.
Tom Preese, in his very interesting article on box rust (Mycologist14 (2000); pp 104-106), gave us the good news that, at least in Britain, Puccinia buxi on Buxus sempervirus is a curious rarity. John Glenn gives us the bad news in his article entitled "What's on the box?" (Journal of the Royal Horticultural Society Volume 125 Part 9. The Garden (September /2000); pp 700-705). A virulent new disease, termed 'box blight', is destroying box specimens (dwarf cultivar 'Suffruticosa') well as whole plantings. The disease, for which there is presently no prophylaxis, can defoliate mature plants in just weeks, to the great detriment of a number of well-established formal gardens. Its cause is an undescribed hyphomycete that was at first thought to be Cylindrocladium scoparium Morgan; the fungus "... infects the leaves causing spots that lead to defoliation, and rapidly moves into the stem tissue, leading to the death of smaller branches. Over a period of a few weeks black streaks appear on the bark and greyish fungus may be seen under leaves."
Phytophthora strikes again! A new disease, 'Sudden oak death', is devastating California's live oaks (Quercus agrifolia), the signature species of scenic coastal woodlands, "...with the ferocity of an oak-tree Ebola virus, causing the trees to sprout sores, hemorrhage sap, and become infested with beetles and various fungi. The trees die within a few weeks of their first symptoms." Science 289 (2000); p 859. The epiphytotic started five years ago with the succumbing of tanoaks (Q. [Lithocarpus] densiflora), understory trees of redwood forests, and has begun most recently to blight the black oak (Q. kelloggii). It is unknown if the new, as yet unnamed, Phytophthora sp. is a recent introduction or a native one that, for unknown reasons, has run amok; so far there is no treatment applicable to California's extensive oak stands. (See also Mycologist 14 (2000); p 93 for reports of a virulent Phytophthora hybrid blight of alders and the recent appearance of the sexual phase of P. infestans that is visiting new havoc on European potato crops.)
A Panorama programme entitled "Britain's Secret War on Drugs" (BBC Channel 1; 2 October 2000) gave detailed information of research that is backed by the United Nations and funded by Britain and America and would use two host specific fungi as potential mycoherbicides. One species, Pleospora papaveracea, could be used to control Papaver somniferum (Mycologist 13 (1999); p 134). The research programme is under the direction of Prof. Abdukarimarov Abdusattar, Director of Uzbekistan's Institute for Plant Genetics, and utilizes the extensive facilities of a restored biological warfare centre abandoned by the Soviet Union. (It was rehabilitated by Mike Greaves, Bristol, Consultant to the UN Drug Control Programme, who thinks the Pleospora project is one of the most exciting that he's been involved in.) A logistic difficulty, however, is that the Tashkent unit is across the border from Afganistan, whose poppy fields are the initiating source of 90% of Europe's illicit heroin. According to a 4 October 2000 report in the International Herald Tribune (IHT) it is also the country currently worst hit by the most severe regional drought in half a century; Uzbekistan, the world's leading cotton grower, is the second worst affected. Afganistan's government, the fundamentalist Taliban, has refused permission for the country's extensive, and lucrative, poppy crops to be destroyed. A similar research programme would use Fusarium oxysporum Schltdl. [f.sp. ?] to eliminate Erythroxylum coca in South America. The leaves of this cultivated shrub are a traditional fatigue reducing masticatory and, today, the source of cocaine. The 'oxy' research, led by Prof. David Sands who discovered the fungus in Hawaii, is backed by the US State Department. Although proved to be very effective in limited field trials, Columbia, today's leading grower of E. coca, has declined to have it tested on its territory. Panorama also highlights the moral dilemma of, on the one hand, the benefits of unilaterally 'taking out' the respective crops to slash the global supply of these contraband drugs (which would be an illegal act of biological warfare) vs. the safety aspects and the possible retalitory action that could be taken by a rogue regime towards major crop plants, such as wheat. (Parenthetically, the 13 October 2000 IHT reported that Pino Arlacchi, the executive director of the United Nations office for Drug and Crime Prevention "... was confident that a 1998 UN pledge to eradicate [by unspecified means] opium poppy and coca bush by 2008 could be fulfilled early.") A synopsis, related links, and a text transcript of the : Panorama programme is available.
The white, Piedmont, truffle (Tuber magnatum Lév. or Pico) was the subject of a lengthy, tabloid-type article in the 8 Dec 00 issue of The Evening Standard (London), entitled "Truffle Fever", with the sub-heading: "Rival gangs are prepared to kill for them. More valuable than gold, they are protected by heavies. We're not talking about diamonds or drugs, but truffles. Nick Foulkes is on the scent". The matter of this hype was a meeting of 'gastrocrats' (restauranteurs, hoteliers, gastronomes, and other elite mycophagists) at a castle near Alba, Italy, for the auction of "the Tartufo d'Alba, the aristocrat of truffles", the one with the most intense smell. Besides the on-the-spot participants, there were TV-crews and satellite-linked, far eastern bidders. The largest specimen, 497g, about the size of a large potato, fetched nearly £5,000, the next down, 436g, went for £2,500, while one at 300g sold for £1,500. Truffle valuation is a recondite mixture of the logic of diamond trading (bigger is better), the domaines of fine crus ("the white truffle of Alba is the Pétrus [Pomerol's most famous wine and currently Bordeux's most expensive] of edible fungus "), and the weather. Prices have also been driven up by the combined effects of loss of natural woodland to modern agriculture and new, far afield, markets. Much of the article is taken up with reporting the economics, scams, and anecdotes characteristic of a rare commodity sought by those who can, and wish to, afford it; and those seeking to cater to them.
The black, Perigord, truffle (Tuber melanosporum Vittad.) was the subject of two reports. The Times (London) (9 December 2000) in a communiqué by Adam Sage entitled "French swallow hard at gourmet prices" noted a pre-Christmas melancholy in the Dordogne where a dry summer reduced the crop to about 15 tonnes from 1999's 25 with a consequent market price of FFr 7,500-9,800 (£700-915)/kg in Paris. A post holiday, illustrated lead article by Patricia Wells in the 12 Jan 01 issue of the International Herald Tribune's International Traveler section, entitled "Ode to the Black Truffle: bring it on and don't be stingy". She points out that truffles are becoming rarer and more expensive (FFr 4,400/kg at the time; ~£426), that many truffle dishes featured in posh restaurants are oversold -- having few truffle pieces and the flavour of what little there is, is masked by most recipes, and that few chefs have much first hand experience with truffles. The author's family have "a small oak tree-framed vineyard" in Vaison-la-Romaine, Provence. She makes the following observations about how to get the best from this rare, coveted, and irreproducible commodity:
"It's hard to believe, but what is most appealing about a truffle is its texture. Crunchy, what the French call croquant, and it's in that crunch that you release in your mouth, throughout all your olfactory senses, the earthy, woodsy, magical fragrance of the truffle. Cook a truffle and you lose both crunch and aroma. Slice it and serve it raw and you still are not there.
"The truffle needs a companion: a touch of olive oil and a sprinkling of French fleur de sel are best, for they provide just enough moisture, just enough seasoning to help the truffle shine. Cut a truffle and leave it on a counter for a few seconds and it dries up, dying a very rapid death."
The Summer, British, Truffle (Tuber aestivum Vittad.) is the least expensive of the true edible tubers; it occurs through most of Europe, including Britain.
Two truffle books to round off. Pegler, D. N., Spooner, B. M. & Young, T.W.K. 1993. British Truffles. RBG, Kew; ISBN 0-947643-39-7. Rocchia, J.-M. 1992. Truffles, the black diamond and other kinds. A. Barthelemy; ISBN 2-87923-050-0, which also includes a chapter on the Chinese truffle (T. indicum Cooke & Massee).
It is now fairly common knowledge that fungi are more akin to animals than to plants. Further evidence that mycology is nudging zoology can be noted in the following recent News Focus statements from Science. Volume 289 (p 1869): "The [marine] bacteria DeLong discovered have light-harnessing abilities previously known to exist in a fungus and in nonbacterial microbes called archaea ... temperatures, followed by a hard freeze, then a quick thaw -- caused the leaves to become filled with cyanogenic glucosides. The tide of voracious catepillars crawling down from the trees is thought to have transferred, via their faeces, cyanogenic materials into the pastures and water troughs. Supporting evidence was that pastures not bounded by cherry trees had no losses.
Foe of faux wines. If you are investing in fine wines the last thing you want to discover several years on is that you've been sold plonk. Such a disaster hit a leading Australian wine maker in 1998 when cases of fake bottles of prestige Penfolds Grange, the country's greatest wine, were found. BRL Hardy Ltd, another major Australian wine maker, is taking hi-tech steps to protect its flagship wine. They are infusing DNA from 125 year old vines, planted by founder Thomas Hardy at its South Australia McLaren Vale vineyard, into the ink used to print the neck label of each bottle of premium Eileen Hardy Shiraz (3000-6000 per year). In cases of doubt the new branding can be read by a sopisticated electronic hand-held scanner. (International Herald Tribune 22 June 2001.)
Glowing report. The August 2001 Biologist has a broad review of bioluminesence in terrestrial and marine animals by V. B. Meyer-Rochow (48, pp 163-167) that includes a figure of green-glowing Mycena lux-coeli. There are two relevant, unreferenced, statements in the text: "Some glowing species of mushrooms (e.g., Mycena and the mycelium of Armillariella ) complete the list of terrestrial biological light producers." and "The light of some toadstools attracts spore-distributing insects (a positive aspect), but it also attacts spore-eating insect larvae (which is clearly less positive). However, tiny parasitic wasps, specialists in killing and destroying spore-eating insect larvae, benefit from the biological light as well, finding it s, or having out of body experiences. Hallucinogens have shown promising results in helping alcoholics, and are being tried as palliatives for depression, schizophrenia, and heroin addiction. Psychiatrists at the University of Arizona are awaiting approval to carry out a study on obsessive compulsive disorder and psilocybin.
Mushrooms don't usually figure in trade wars but they are part of a dispute between Japan and China. A figure of Lentinula edodes accompanied a report in the Wednesday, 11 April 2001 IHT and is captioned: "Shiitake like these are at the heart of Tokyo's argument with Beijing over low-cost imports". In the text, the article says that the nub of the problem is "How to stop Chinese farmers from flooding Japanese supermarkets with tons of low-cost leeks and shiitake, the dried mushrooms that play a big role in Japanese cuisine[, and that] Prime Minister Yoshiro Mori's cabinent moved Tuesday to slap tariffs on Chinese imports of leeks, mushrooms and a type of straw used to fashion tatami mats." Further on, it states that since 1996 imports of leeks had increased twentyfold and that that of mushrooms and tatami straw had doubled.
The 24 April 2001 IHT reported the death, 10 April, of Richard Evans Schultes at age 86. A Harvard professor, he was known as: the "jungle botanist", the founder of ethnobotany, and the world's foremost expert on hallucinogenic and medicinal plants. His Harvard Ph.D thesis on hallucinogenic mushrooms was discovered in 1953 by Gordon Wasson, whose hobby at the time was the study of the role of mushrooms in European cultures. This was the start of a chain of events. After reading Schultes' thesis, Wasson rapidly left for Oaxaca where he "... managed to find a traditional healer who allowed him to ingest the mushrooms as part of a sacred ceremony. His description of the experience was published in a Life magazine article titled 'Seeking the Magic Mushrooms.' "; this, in turn, was read by a young Harvard lecturer, Timothy Leary, who, a few years later tried the mushrooms himself. And the rest, as they say, is history.
Common names of mushrooms and other macrofungi have become a major concern of American mycologists. Inoculum (51/5; October 2000) reports on the agreement by the Mycological Society of America and the North American Mycological Association to establish a joint Commission on Common Mushroom Names for North America by the respective presidents, Orson Miller, Jr. and Alein Stanley. The MSA's concern has been intensified by the growth of amateur mycology, accompanied by an increase of popular books on identifying macrofungi that often have different common names for the same species or the same common name for different species. Also noted was the desire to list common names in non-English languages, particularly Spanish. A brief tour of British field guides indicates a fair uninimity in traditional vernacular names for the commonest mushrooms (e.g., Horse mushroom for Agaricus arvensis). In general, the species in most such books are limited to the formal Latin name. Shelley Evans, the BMS Conservation officer, comments in the July Field Mycology (2001, 2: 89) that "It is hoped that a UK project to recommend a list of approved English names for fungi will be undertaken later this year, part funded by the British Mycological Society. Such work is long overdue to provide guidance and reduce the confusing proliferation of vernacular names." Meanwhile, Læssøe's Mushrooms (Dorling Kindersley, 1998, ISBN 0-5173-1070-0) bestows supposed common names for all the species included (e.g., Little Japanese umbrella for Coprinus plicatilis).
Not guilty! During April and May of this year [2001]the Sports media were replete with stories of a mysterious horse epizootic; e.g., the International Herald Tribune's 12/13 May 2001 report was headlined "Death stalks Kentucky's stables -- Mystery disease claims numerous foals in prime breeding region". Mare's were experiencing early spontaneous abortions or giving birth to stillborn foals that numbered in the thousands resulting in great financial loss to this region of pedigreed race horses. It was insinuated that the cause of the deaths was perhaps from a mycotoxin produced by a fungus infecting Kentucky's renowned blue grass during a spell of warm, dry weather, even though other animals in the area were unaffected. But no fungus or other cause could be established and the cause of the malady remained a mystery. Subsequently (IHT 15 June 2001), circumstantial suspicion focused on cyanide produced by wild black cherry trees (Prunus serotina ). These small trees are a common hedgerow plant and in the spring they become infested with the unsightly nests of the orchard tent catapillar (larva of Malacosoma americana ). The exceptional weather this particular spring -- warm temperatures, followed by a hard freeze, then a quick thaw -- caused the leaves to become filled with cyanogenic glucosides. The tide of voracious catepillars crawling down from the trees is thought to have transferred, via their faeces, cyanogenic materials into the pastures and water troughs. Supporting evidence was that pastures not bounded by cherry trees had no losses.
Foe of faux wines. If you are investing in fine wines the last thing you want to discover several years on is that you've been sold plonk. Such a disaster hit a leading Australian wine maker in 1998 when cases of fake bottles of prestige Penfolds Grange, the country's greatest wine, were found. BRL Hardy Ltd, another major Australian wine maker, is taking hi-tech steps to protect its flagship wine. They are infusing DNA from 125 year old vines, planted by founder Thomas Hardy at its South Australia McLaren Vale vineyard, into the ink used to print the neck label of each bottle of premium Eileen Hardy Shiraz (3000-6000 per year). In cases of doubt the new branding can be read by a sopisticated electronic hand-held scanner. (International Herald Tribune 22 June 2001.)
Glowing report. The August 2001 Biologist has a broad review of bioluminesence in terrestrial and marine animals by V. B. Meyer-Rochow (48, pp 163-167) that includes a figure of green-glowing Mycena lux-coeli. There are two relevant, unreferenced, statements in the text: "Some glowing species of mushrooms (e.g., Mycena and the mycelium of Armillariella ) complete the list of terrestrial biological light producers." and "The light of some toadstools attracts spore-distributing insects (a positive aspect), but it also attacts spore-eating insect larvae (which is clearly less positive). However, tiny parasitic wasps, specialists in killing and destroying spore-eating insect larvae, benefit from the biological light as well, finding it highly attractive and, thus, the light takes on a positive role again." Perhaps a knowledgeable reader could provide us fuller information.
This issue's column is devoted to some challenging issues of fungal systematics and nomenclature, starting with three reports from the October 2001 issue of Inoculum .
1. Join the fray!, invites Lorelei Norvell (p 5). Last year Coprinus was partitioned into four genera on the basis of molecular and (subsequently appreciated) taxonomic characters: Coprinopsis, Parasola, Coprinellus (all in the new family Psathyrellaceae), and Coprinus ss (Agaricaceae). The IAPT Nomenclature Committee for Fungi is considering a proposal to change the long standing lectotype of Coprinus, C. comatus, to C. atrementarius (presently C'opsis atrementaria). This change in typification would achieve the following: (i) At least half of the former coprini would remain in the genus Coprinus, (ii) The family name Coprinaceae would be restored, placing Psathyrellaceae into synonymy, (iii) Coprinus comatus, however, would have to be transferred to another genus (it and two other species are now recognized as belonging with Lepiota and Agaricus), (iv) Coprinus cinereus (now C'opsis cinerea), the most cited species in the scientific literature, would revert to C. cinereus, (v) It would establish a precedent for changing a type based on molecular phylogenetic conflicts. Which type species would you prefer for Coprinus? I have put a copy of Lorelei's report on line Coprinus with a mailto link to her e-mail to facillitate a response to her poll (please put your choice in the subject line -- either C. comatus or C. atrementarius); your straw vote counts! - it can help the IAPT with its decision.
2. Scott Redhead (p 6) explains the difference between ' : ' and 'ex' in scientific authorities: "Since 1981 (the Sydney Code), the colon specifically designates sanctioned status for names in either of two publications (and only two) as designated by Art. 13 -- E. M. Fries'sSystema Mycologicum and its Elenchus [a multi-volume set spanning 12 years], and Persoon's Synopsis Methodicum Fungorum No other authority and no other publication warrant usage of the colon. 'Ex' is still available in specific cases of validation of previously invalid names, but they are far less frequent than previously believed (Art. 46). ... Many authorities can be checked at the following two sites listing names in these publications: Fries; Persoon.
3. From Walter Gams, Chair of MSA's Nomenclature Committee (p 17). (i) Notice that the Committee for Fungi had approved the conservation of Rhizoctonia with the conserved type R. solani. (ii) The formation of a discussion group, proposed by David Hawksworth, to examine the merits of eventually abolishing Article 59 that regulates names of fungi with a pleomorphic life cycle. Under scrutiny were: 1) whether the sharp distinction between teleomorph and anamorph genera could be revoked; 2) the possibility of equal status of telemorph and anamorph specific epithets and the possibility of recombining them freely from any genus to another; 3) doing away all together with a duplicate nomenclature for admittedly connected morphs. Immediate removal of the Article would result in considerable destablization of names, but less radical action might be possible. Gregoire Hennebert is preparing a detailed analysis. If you have opinions, the group can be reached through art59@kendy.up.ac.za; for reports of the Committee see URL above. Links to Art. 59 and the ICBN, respectively, will be found at Mycolegium in the Mycovescence section.
Some other systematic sites linked from this last URL. The proposed PhyloCode has generated a great deal of heat between proponents and adversaries. It would do away with the Linnaean heirarchy system of supraspecific taxa by interpreting taxon names with reference to phylogenetic trees; 'species', however, would, pro tem, be retained. Available on line are the text of the Proposal and transcripts of views by, respectively, Benton, Pleijel & Rouse, and Redhead. Counter to this, the proposed BioCode (4th draft, 1997) considers, in extenso, the feasability of a single, unified code of (Linnaean) nomenclature to replace the five existing ones: Botanical, Zoological, Bacteriological, Cultivated Plants, and Viruses. Deep Hypha is a major programme funded by the US National Science Foundaion to a group of mycologists "to plan an attack on a phylogeny for all fungi and fungus-like organisms." Interested mycologists are strongly encouraged to peruse the plan and send their comments to the project leaders.
The cell cycle, characteristic of all eukarotic cells, is divided into four phases. During the first phase (G1) the cell grows until it has reached a certain size whereupon it enters the phase of DNA-synthesis (S) in which the chromosomes are duplicated. During the next phase (G2) the cell prepares itself for division. During mitosis (M) the chromosomes are separated and segregated to the daughter cells, assuring each gets the same chromosome complement. The cells are then back in G1 and the cell cycle is completed. Last October The Nobel Prize in Physiology or Medicine was awarded jointly to Leland H. Hartwell, R. Timothy (Tim) Hunt, and Paul M. Nurse for their seminal discoveries of its key regulators. The following account is compiled and adapted from the Press Release announcement of the Prize and Professor Anders Zetterberg's Presentation Speech (full text of both are available at the above Nobel Internet site).
The three Laureates discovered the key regulators of the cell cycle: cyclin dependent kinase (CDK) and cyclin. Together these two components form an enzyme, in which CDK is comparable to a "molecular engine" that drives the cell through the cell cycle by altering the structure and function of other proteins in the cell. Cyclin is the main switch that turns the "CDK engine" on and off. This cell cycle engine operates in the same way in such widely disparate organisms as yeast cells, plants, animals, and humans.
Lee Hartwell exploited Saccharomyces cerevisiae to identify mutants that stopped in the cell cycle when they were cultured at an elevated temperature. Using this method he discovered, in the early 1970s, dozens of genes specific to the cell division cycle, which he named CDC genes. One of these, cdc28, controlled initiation (the "start" function) of each cell cycle. He also formulated the concept of "checkpoints", which ensure that cell cycle events occur in the correct order or are arrested when DNA is damaged. (Checkpoint defects are considered to be one of the reasons behind the transformation of normal cells into cancer cells.)
Paul Nurse studied the fission yeast Schizosaccharomyces pombe. In the late 1970s and early 1980s he discovered the gene cdc2, which could be mutated in two different ways. Either the cells did not divide, or they divided too early. From this he correctly concluded that cdc2 controls cell division. He later discovered that cdc2 not only controls cell division, the final event of the cell cycle, but also has a key regulatory function for the whole cell cycle, including that described for cdc28 ("start") in baker's yeast. This key function was shown to be that of CDK in the cell cycle engine (activation of CDK is dependent on reversible phosphorylation, i.e., that phosphate groups are linked to or removed from proteins). By moving human genes into yeast cells, in 1987, he isolated a human cdc2 gene. This human cdc2 gene functioned perfectly in yeast cells. Thus, the CDK function in the cell cycle engine has been conserved through more than one billion years of evolution ‹ from yeast to man.
Tim Hunt, using sea urchin eggs, discovered the other key component of the cell cycle engine in 1982: the protein he named cyclin. This protein regulates the function of the CDK molecule, increasing in amount before cell division but disappearing abruptly when the cells have divided. This periodic degradation, therefore, is a fundamental control mechanism. His later experiments also showed the existence of cyclins in other, unrelated species. Thus cyclins, like CDK, have been conserved during evolution.
Dr. Zetterberg concluded his Presentation by saying that these fundamental discoveries had profoundly increased our understanding of how the cell cycle is controlled and that this new knowledge has had a huge impact on cell biology with broad applications in many fields of biology and medicine. He then extended warmest congratulations from The Nobel Assembly at Karolinska Institutet and invited them to come forward to receive the Nobel Prize from the hands of His Majesty the King.
The above Nobel website also has links for each Laureate: to his CV, Prize Diploma, and videos of the Prize being presented to him and of his acceptance lecture.
Further information about the two yeasts can be found at Nature 415 (2002): 845 - 848 (News and Views) in which the author states, inter alia, that "It [is] not particularly surpris[ing] that budding and fission yeast differ so much at the genomic level, as they are not very closely related, and many genetic and physical differences had been known before the genomes were sequenced. But the fact that many further differences have been uncovered by genomic comparisons suggests that it could prove valuable to sequence the genomes of other biologically diverse yeast species, and, more broadly, other fungi."; there is also an animation of pombe's cell cycle.
The 26 July 2002 issue of Science 297: 537-541) has a review article by J.K.M. Brown james.brown@bbsrc.ac.uk & M. S. Hovmøller mogens.hovmoller@agrsci.dk entitled "Aerial dispersal of pathogens on the global and continental scales and its impact on plant disease". It focuses on long-distance [500 or more km, wind] dispersal (LDD) as an important survival strategy for crop disease fungi.
The article discusses how LDD enables the fungi to rapidly colonize a new territory or to migrate between summer and winter habitats. It is illustrated with three maps. The first, a global map, uses red and blue arrows to indicate invasions of new territories. The 'red' dispersals, probably resulting from a few long-distance, wind wafted spores, include wheat stem rust Puccinia graminis f. sp. tritici from southern Africa to Australia (1969), coffee leaf rust Hemileia vastatrix from Angola to Brazil (1970), and sugarcane rust Puccinia melanocephala from West Africa (Cameroon) to Dominican Republic (1978). The 'blue' dispersals represent pathogens that were probably introduced into their new territories on infected plant materials or by people and were subsequently spread by airborne spores. The oldest and most notorious of these latter is potato late blight, Phytophthora infestans , A1/A2 mating types from Mexico to Europe (1845; 1976/7, respectively: see this column, Mycologist 13, p 179); see #18. Two other major dispersals of this type are the American chestnut blight, Cryphonectria parasitica, introduced from east Asia (Japan?) to eastern North America (1904) and wheat yellow rust, P. striiformis f. sp. tritici, from Europe to Australia (1979). Also included on this map is the worldwide distribution of black Sigatoka disease of banana, Mycosphaerella fijiensis. The other, larger scale, maps present, respectively, the dispersal of wheat yellow rust in China and the distribution of its genotypes in northwest Europe.
The review gives an extensive analysis of these and other phytopathogen dispersals (e.g., barley powdery mildew), the mechanisms of host susceptibility (arabica coffee plantations in America, for example, source to a single bush from Java in 1706), and brings together new ideas from epiphytology and genetics.
Meanwhile, back at the truffiér. The London Times had four articles on truffles in its Monday, 8 July 2002 issue; three took nearly all of p 3. The illustrated lead article, "Secret shire garden where black diamonds grow", by Velerie Elliott reported on Britain's expected first commercial truffle harvest. She describes how Nigel Hadden-Paton and Adrian Cole, founders of Truffle UK Ltd, had planted and inoculated 100 oak and hazel trees at a closely guarded secret location in Hertfortshire. The specially treated trees, now 6' tall, were planted four years ago and experts believe that the plantation is now ready to produce its first crop of Pèrigord truffles ( Tuber melanosporum). The two entrepreneurs, who had a stand at the Royal Agriculural Show at Stoneleigh Park, Warwickshire during the first week of July, "... had been trying for years to learn the secret of truffle growing, but ... the French and Italians, the past masters of the art, had given them the cold shoulder. Instead they had been able to purchase a licence from the New Zealand Institute for Crop and Food Research, a Crown agency [in Mosgiel], which has perfected a technique of infecting oak and hazel seeds with truffle fungus."
The article goes on to say that "They are convinced that there is the potential for thriving truffle grounds on the chalk and limestone areas of Britain. They have identified the most likely soils as the Chilterns; the North and South Downs, between Norwich and Cambridge; in Hampshire and Wiltshire into Dorset; between Hull and Lincoln; north of Oxford; south of Gloucester; the South Coast around Portland; west Devon around Brixham; west of York to Nottingham; and parts of the Peak District." A map quickly identifies these regions, suitable for T. melanosporum and T. uncinatum, the Burgundy or summer sruffle.
Truffle UK Ltd is eager to obtain "... trial sites and for planting to take place in March. They suggest 400 treees per acre but do not recommend growing oak and hazel saplings near to exising woodland. The two businessmen also believe that the trees could become the latest fashionable garden accessory .... They are willing to sell plants in small quantities for unusual christening, birthday, or anniversary gifts." The company is also anxious to forge joint ventures with British villa owners on the continent to establish truffiérs (truffle grounds) in southwest France and in Tuscany and Umbria, Italy.
Elsewhere on the page is the mandatory truffle receipe with the useful information that sinking fresh truffles in a jar of risotto rice or a bowl of eggs (the aroma penetrates to the yolk and white) for a day or two imparts a delicous flavour for later use.
Lower down the page is Robin Young's article entitled "Beware: the sow that digs up a tuber will not be easily denied". The first paragraph reads: "The gourmet's passion for the truffle depends entirely on its strange but utterly distinctive aroma, which is redolent of intimate body contact and sexual arousal. Unsurprisingly, the truffle has a long-established reptuation as an aphrodisiac of singularly seductive power." And further on he notes that "Sows are known to be especially keen to pick up the scent, because the fungal tuber excretes pheromones that resemble those of a boar in heat."
The fourth article, on p. 19/Comment, is entitled "Snouting out a Goldmine - Looking forward to Hertfordshire's first truffle harvest". It identifies the secret site as being in the neighbourhood of Tring and that the truffle orchard will have several species. It also notes that if the enterprise is successful it can expect to make at least £22,750 and acre for about 100 lb of truffles, which is why Hadden-Paton and Cole's stand at the Royal Show attracted so much attention from members of the very depressed farming community.
The New Scientist Christmas issue (22/29 December 2001, pp 65-67) presents the Antipodean side of the story in an article entitled "Festive fungi - 'Tis the season to eat truffles. But farming could make them a year-round treat". It notes that during the past century or so there has been a precipitous fall in Europe's wild truffle harvest: from an average season's yield of 1000 tonnes at the turn of the last century to what is now considered a bumper harvest of 50 tonnes. The cause of this decline is unknown, but suggestions include loss of traditional knowledge consequent WWI/II, intensification of agriculture and its associated deforestation and pesticide use, acid rain, and overharvesting. For whatever reason, most of France's truffles are now farmed (thanks to research led by Gérard Chevalier of the National Institute for Agronomic Research, Clermont-Ferrand) and other countries are piling in, most notably Australia and New Zealand. New Zealand now has six t truffiérss and more large plantations are under way. In Australia, Tasmania now has 28 truffiérs, six of which produced truffles this year, and many more truffières are being developed on the mainland. All of this promises truffles, to those who can afford them, throughout the year. (On the subject of locating truffles, the article points out that while sows are naturally attracted to truffles, trained dogs are now the locators of choice because "many trufficulteurs lost fingers trying to stop their overexcited sow from scoffing the spoils.")
An earlier report on truffles appeared in Mycological Dispatches, Mycologist 15/2(2001); see #24.
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