Stripe smuts of grasses: one lineage or high levels of polyphyly?

Stripe smut of grasses, Ustilago striiformis s.l., is a complex of smut fungi widely distributed over temperate and subtropical regions. The disease results in the shredding and death of leaf tissue following the rupture of elongated sori. Nearly 100 different grass species in more than 30 genera are infected by stripe smut. During the last two centuries more than 30 smut taxa have been described from members of this complex. The present study attempts to clarify the taxonomy and phylogeny of stripe smuts on grasses by analysing both morphological and molecular data. More than 200 specimens from different continents and host plants were examined. DNA was extracted from teliospores of 23 specimens from different hosts collected in Europe, Asia, and North America. The ITS and LSU regions of ribosomal DNA were amplified and used in phylogenetic analyses. The results of Maximum Parsimony and Bayesian analyses demonstrated that there are several lineages of stripe smut fungi. Analyses of morphological characters assessed with light and scanning electron microscopy showed high support for the differentiation of two clades as distinct from U. striiformis s.l., i.e., U. nunavutica sp. nov. and U. bromina. Two additional clades, U. striiformis s.str. on Holcus and a clade containing specimens from Elymus, were identified with molecular data although morphological differences were not apparent. Descriptions are given for each species.

The mode of reproduction in natural populations of ascomycetous fungus, Emericella nidulans, from Israel.

The mode of reproduction of the soil ascomycetous fungus Emericella nidulans of Israeli populations was studied using 15 microsatellite (simple sequence repeats or SSR) trinucleotide markers. The study was performed in three canyons: two located in the northern part of Israel (Mount Carmel and western Upper Galilee) and one in the southern Negev desert. In each canyon, E. nidulans strains were isolated from the opposite slopes and (in the desert canyon) the valley bottom. Testing the reproductive structure of the populations indicated the presence of sexuality in the northern population and predominant clonality in the desert population. The predominantly clonal character of the desert population of E. nidulans was explained by the assumption that for relevant multilocus systems of a fungus, only several haplotypes can survive in the rather constant, extremely stressful desert conditions. Additionally, the very low density of E. nidulans populations in the soil of the desert canyon, which reduces the probability of finding a sexual partner, might favour predominant clonality via selfing. Increasing sexuality in E. nidulans populations on the north-facing slopes of the northern canyons may be a result of biotic stress (pressure of competitive fungal species), due to the more mild ecological conditions in these canyons.

Carbon and nitrogen source effects on basidiomycetes exopolysaccharide production.

The capability to synthesize the extracellular polysaccharide (EPS) is widespread among eight mushroom species which accumulated 0.6-2.2 g/l of EPS in submerged cultivation. Glucose, maltose, and mannitol were the most appropriate carbon sources for biomass and EPS production. Organic nitrogen sources appeared to be the most suitable nitrogen sources for biomass and EPS accumulation. The cultivation process in shake flasks was successfully reproduced in a laboratory fermentor with enhanced EPS production. The highest yield of EPS (3.8-4.0 g/l) was achieved in cultivation of Agaricus nevoi and Inonotus levis.

Disposal of agro-industrial by-products by organic cultivation of the culinary and medicinal mushroom Hypsizygus marmoreus.

Organic mushroom cultivation is one of the fastest growing segments of agriculture. At the core of the organic philosophy lies a ban on the use of synthetic fertilizers, pesticides and herbicides, in addition to such tenets as animal welfare, energy efficiency, and social justice. Hypsizygus marmoreus (HM) is a highly praised cultivated culinary and medicinal mushroom. The objective of this paper was to assess the suitability of different spawn media and then the potential of various cultivation substrates to support HM mushroom production compatible with organic standards. This objective was met through the setup of a low-cost cultivation infrastructure. First, seven types of spawn media were tested; then we tested 24 substrates made from organic by-products for their biological efficiency (BE) with strain HM 830, using the liquid inoculation method. The best substrate in terms of BE was corn cob with bran and olive press cake, with a BE of 85.6%. The BE of the same composition but without olive press cake was only 67.5%. The next best substrates were cotton straw combinations with a BE of 31.5-53%. The spent mushroom substrate provides a good method for the disposal of solid waste. The guidance provided in this research complies with organic mushroom cultivation standards and can be used to produce certified organic mushrooms. In addition, it allows responsible and beneficial disposal of a large amount of solid agro-industrial waste.

Survival of filamentous fungi in hypersaline Dead Sea water.

A variety of filamentous fungi have recently been isolated from the Dead Sea (340 g/L total dissolved salts). To assess the extent to which such fungi can survive for prolonged periods in Dead Sea water, we examined the survival of both spores and mycelia in undiluted Dead Sea water and in Dead Sea water diluted to different degrees with distilled water. Mycelia of Aspergillus versicolor and Chaetomium globosum strains isolated from the Dead Sea remained viable for up to 8 weeks in undiluted Dead Sea water. Four Dead Sea isolates (A. versicolor, Eurotium herbariorum, Gymnascella marismortui, and C. globosum) retained their viability in Dead Sea water diluted to 80% during the 12 weeks of the experiment. Mycelia of all species survived for the full term of the experiment in Dead Sea water diluted to 50% and 10% of its original salinity. Comparison of the survival of Dead Sea species and closely related isolates obtained from other locations showed prolonged viability of the strains obtained from the Dead Sea. Spores of isolates obtained from the terrestrial shore of the Dead Sea generally proved less tolerant to suspension in undiluted Dead Sea water than spores of species isolated from the water column. Spores of the species isolated from the control sites had lost their viability in undiluted Dead Sea water within 12 weeks. However, with the exception of Emericella spores, which showed poor survival, a substantial fraction of the spores of Dead Sea fungal isolates remained viable for that period. The difference in survival rate between spores and mycelia of isolates of the same species points to the existence of adapted halotolerant and/or halophilic fungi in the Dead Sea.

Medicinal mushrooms as a source of antitumor and immunomodulating polysaccharides.

The number of mushrooms on Earth is estimated at 140,000, yet maybe only 10% (approximately 14,000 named species) are known. Mushrooms comprise a vast and yet largely untapped source of powerful new pharmaceutical products. In particular, and most importantly for modern medicine, they represent an unlimited source of polysaccharides with antitumor and immunostimulating properties. Many, if not all, Basidiomycetes mushrooms contain biologically active polysaccharides in fruit bodies, cultured mycelium, culture broth. Data on mushroom polysaccharides have been collected from 651 species and 7 infraspecific taxa from 182 genera of higher Hetero- and Homobasidiomycetes. These polysaccharides are of different chemical composition, with most belonging to the group of beta-glucans; these have beta-(1-->3) linkages in the main chain of the glucan and additional beta-(1-->6) branch points that are needed for their antitumor action. High molecular weight glucans appear to be more effective than those of low molecular weight. Chemical modification is often carried out to improve the antitumor activity of polysaccharides and their clinical qualities (mostly water solubility). The main procedures used for chemical improvement are: Smith degradation (oxydo-reducto-hydrolysis), formolysis, and carboxymethylation. Most of the clinical evidence for antitumor activity comes from the commercial polysaccharides lentinan, PSK (krestin), and schizophyllan, but polysaccharides of some other promising medicinal mushroom species also show good results. Their activity is especially beneficial in clinics when used in conjunction with chemotherapy. Mushroom polysaccharides prevent oncogenesis, show direct antitumor activity against various allogeneic and syngeneic tumors, and prevent tumor metastasis. Polysaccharides from mushrooms do not attack cancer cells directly, but produce their antitumor effects by activating different immune responses in the host. The antitumor action of polysaccharides requires an intact T-cell component; their activity is mediated through a thymus-dependent immune mechanism. Practical application is dependent not only on biological properties, but also on biotechnological availability. The present review analyzes the pecularities of polysaccharides derived from fruiting bodies and cultured mycelium (the two main methods of biotechnological production today) in selected examples of medicinal mushrooms.

The effect of Psilocybe cubensis extract on hippocampal neurons in vitro.

The action of P. cubensis mushroom extract, containing psilocybin (PCB) and psilocin, on spike activity of hippocampal CA1 pyramidal neurons was studied in in vitro rat brain slices. In 38 (76%) out of 50 investigated neurons spike activity was decreased, in 2 (4%) cells it increased. There was no response 10 (20%) neurons. Application of the extract caused short burst firing in 12 (24%) neurons. All neurons showing inhibition during PCB-containing extract application, were also inhibited by serotonin (5-HT). Usually inhibitory reaction did not last over 4-5 min upon 3 min extract application and could be prolonged up to 10-43 min up on serotonin application. Part of neurons were inhibited by serotonin and did not react to extract application. Inhibitory reactions induced by extract application were blocked by ritanserin in half of the tested units and were induced due to activation of 5-HT2 serotonin receptors. The extract suppressed excitative spike reactions caused by application of L-glutamic acid. It is concluded, that application of PCB-containing extract in most cases reduced spike activity in hippocampal CA1 pyramidal neurons and suppressed glutamate transmission.

Therapeutic effects of substances occurring in higher Basidiomycetes mushrooms: a modern perspective.

This review highlights some of the recently isolated and identified substances of higher Basidiomycetes mushrooms origin that express promising antitumor, immune modulating, cardiovascular and hypercholesterolemia, antiviral, antibacterial, and antiparasitic effects. Medicinal mushrooms have a long history of use in folk medicine. In particular, mushrooms useful against cancers of the stomach, esophagus, lungs, etc. are known in China, Russia, Japan, Korea, as well as the U.S.A. and Canada. There are about 200 species of mushrooms that have been found to markedly inhibit the growth of different kinds of tumors. Searching for new antitumor and other medicinal substances from mushrooms and to study the medicinal value of these mushrooms have become a matter of great significance. However, most of the mushroom origin antitumor substances have not been clearly defined. Several antitumor polysaccharides such as hetero-beta-glucans and their protein complexes (e.g., xyloglucans and acidic beta-glucan-containing uronic acid), as well as dietary fibers, lectins, and terpenoids have been isolated from medicinal mushrooms. In Japan, Russia, China, and the U.S.A. several different polysaccharide antitumor agents have been developed from the fruiting body, mycelia, and culture medium of various medicinal mushrooms (Lentinus edodes, Ganoderma lucidum, Schizophyllum commune, Trametes versicolor, Inonotus obliquus, and Flammulina velutipes). Both cellular components and secondary metabolites of a large number of mushrooms have been shown to effect the immune system of the host and therefore could be used to treat a variety of disease states.

Fungal life in the extremely hypersaline water of the Dead Sea: first records.

The first report, to our knowledge, on the occurrence of filamentous fungi in the hypersaline (340 g salt l-1) Dead Sea is presented. Three species of filamentous fungi from surface water samples of the Dead Sea were isolated: Gymnascella marismortui (Ascomycota), which is described as a new species, Ulocladium chlamydosporum and Penicillium westlingii (Deuteromycota). G. marismortui and U. chlamydosporum grew on media containing up to 50% Dead Sea water. G. marismortui was found to be an obligate halophile growing optimally in the presence of 0.5-2 M NaCl or 10 30% (by volume) of Dead Sea water. Isolated cultures did not grow on agar media without salt, but grew on agar prepared with up to 50% Dead Sea water. This suggests that they may be adapted to life in the extremely stressful hypersaline Dead Sea.

Cobalt 60 radiation and growth of eleven species of micro-fungi from Evolution Canyon, Lower Nahal Oren, Israel.

Eleven micro-fungal species isolated from both the north facing slope (NFS) and the south facing slope (SFS) of Evolution Canyon, Lower Nahal Oren, Israel, were examined for growth rates before and after exposure to 60Co irradiation. Species of Alternaria, Aspergillus, Humicola, Oidiodendron, and Staphylotrichum from SFS grew faster than the NFS isolates while Fusarium, Sordaria, and Stachybotrys grew at greater rates from the NFS than from the SFS. Mucor and Ulocladium isolates grew at the same rate from both SFS and NFS. The eleven isolates from each slope were next subjected to 60Co irradiation. At 40,000 rads exposure, Alternaria, Fusarium, and Stachybotrys grew more rapidly when isolated from the NFS, while Humicola and Staphylotrichum grew at a faster rate when isolated from the SFS. Aspergillus, Mucor, Sordaria, and Ulocladium from both the NFS and the SFS had relatively the same growth rate at 40,000 rads exposure. At 400,000 rads exposure, growth rates remained much the same for both the N and S exposed isolates as they were at 40,000 rads. Above 10(6) rads, growth ceased but recovery occurred at various times for individual isolates of the same species from opposing canyon slopes.

Sparse diversity of potential pathogenic soil micro-fungi in the Ukraine.

Soil from steppe and garden reserves, and urban park and wharf regions in the Ukraine, U.S.S.R., were studied for keratinophilic as well as for other predominant micro-fungal species. Most of the fungi were nonpathogens, and potential skin infecting fungi were limited to Microsporum gypseum and Trichophyton ajelloi. Species diversity identified population variation between collection sites.