Cryophilic fungi to denote fungi in the cryosphere

Fungi are widely distributed in the cryosphere where the habitat is constantly or seasonally covered with snow and/or ice. Fungi normally have different cells in their life cycle; fungal thermal dependence varies according to their life cycle stages and is completely different from that of bacteria. Examples are illustrated to show that the concept of psychrophile by Morita (1975) does not apply to fungi, and we propose a new term “cryophilic fungi” for those that spend a certain life stage or whole life cycle (sexual and/or asexual reproductive stages) in the cryosphere.     

Coprophilous fungi of the horse

A total of 1267 microfungi, including 35 Myxomycetes, were recorded from the fecal samples of the 60 horses; of these 395 were found on 20 saddle-horse feces, 363 on 20 race-horses and 509 on 20 working-horses. Eighty two species representing 53 genera were recorded; of these 7 were Zygomycetes, 18 Ascomycetes, 1 Basidiomycetes and 25 Fungi Imperfecti: 2 Myxomycetes. Common coprophilous fungi are in decreasing orderPilobolus kleinii, Saccobolus depauperatus, Mucor hiemalis, Lasiobolus ciliatus, Podospora curvula, Petriella guttulata, M. circinelloides, Coprinus radiatus, Dictyostelium mucoroides, Sordaria fimicola, C. miser, C. stercorarius, Acremonium sp., Coprotus granuliformis, Graphium putredinis, Iodophanus carneus, Chaetomium murorum, Podospora communis, P. inaequalis, P. setosa, Saccobolus versicolor andCladosporium cucumerinum. Species ofMyrothecium verrucaria, Actinomucor elegans, Kernia nitida, Spiculostilbella dendritica andMucorparvispora were found exclusively in working-horses feces.Badhamia sp., Anixiopsis stercoraria, Echinobotryum state ofD. stemonitis, Geotrichum candidum andOidiodendron sp. were found only in saddle-horses feces.Chlamidomyces palmarum andPhilocopra sp. were found exclusively in race-horses feces.Notes on infrequent or interesting fungi includeThamnostylum piriforme, Phialocephala dimorphospora, Rhopalomyces elegans andSpiculostilbella dendritica.     

Understanding the morphology of fungi

Filamentous fungi comprise an industrially very important collection of microorganisms, since they are used for the production of a wide variety of products ranging from primary metabolites to secondary metabolites and further on to industrial enzymes (such as proteases, lipases and antibiotics). It is known that fungal morphology is often considered as one of the key parameters in industrial production. For the production of fungal metabolite products, the desired morphology varies from one product to another. Many parameters affect the morphology of fungi during the process of fermentation, among them speed of agitation, specific growth rate, dissolved oxygen, number of spores or conidia per liter of fermentation broth are important and should be considered when higher yield is desired in the process. It is, therefore, of considerable importance to understand the mechanism underlying the morphology of the cell, its growth and product formation by filamentous fungi. Such knowledge may be used in the optimization of the microbial process. Several literatures with various fungi to study their morphology, relating enzyme or product production to the character of the fungi in the study is reviewed. It is also considered that how the process parameters affects the morphology. The aim of this communication is to review the relevant literature to understand the morphology of filamentous fungi.     

Against the naming of fungi

The use of molecular bar-coding and consensus on nomenclatural practices has encouraged optimism about the future of fungal taxonomy and systematics. There are, however, profound deficiencies in our understanding of fungal diversity and broader problems with the taxonomic enterprise that deserve greater attention. For 250 years mycologists have tried to reconcile fungal diversity with the Linnean fantasy of a divine order throughout nature that included unambiguous species. This effort has failed and today's taxonomy rests on an unstable philosophical foundation. Rather than persisting with the present endeavour, it may be more fruitful to abandon the notion of fungal species pending further basic research. In the meantime, mycologists should consider tagging collections with digital codes and assigning these operational taxonomic units to higher taxonomic ranks whose objective reality is corroborated by strong phylogenetic evidence.     

Inventoring the fungi of Panama

Records of fungi in Panama scattered in literature are presented in a preliminary annotated checklist which is published in Panama. It includes 1807 species and subspecific taxa in 646 genera. The data allow to trace more than 100 years of history of mycology in Panama, presented here for the first time. The species richness is analyzed numerically with respect to the systematic position of the species and their ecology. Considering the numbers of records for different regions of Panama, a comparison with numbers of species published for some other neotropical countries, as well as recent experience collecting fungi in Panama, the incompleteness of the checklist is evident. Values of relative species richness of different systematic groups in Panama compared to values of the same groups as known worldwide, show that our knowledge is fragmentary in Panama especially for Agaricales, Uredinales, and some groups of microfungi. We are still in the pioneer phase of mycological investigation in Panama.     

Inventorying the fungi of Mexico

Conservation of the vegetation, analysis of the knowledge of the diversity of fungi, new biological methods and estimates of the numbers of species of fungi that grow in Mexico are discussed. The great forest destruction that is occurring and the loss of fungal diversity in the country is seriously depleting total biodiversity, mainly in the tropics. Methods to establish the number of Mexican species of fungi are proposed based on an average of: (1) the numbers of fungal obligates of vascular plants and animals and of the saprobic species; (2) extrapolating the number of the British fungi to Mexico, taking the British mycota as the best known in the world; and (3) extrapolating to the country the number of species known to occur in the State of Veracruz (Mexico), the best known in the country. The average of these three calculations yields about 200 000 species of fungi for Mexico. Of these, only 3.5% are known, despite considerable progress having been made in the inventory of the country's fungi in the last 30 years. It is concluded that it is necessary to place more emphasis on alpha taxonomy, to train more specialists and to prepare monographs of several groups of fungi.     

Effect of a preparation from Chaetomium fungi on the growth of phytopathogenic fungi

We studied the fungicidal activity of a biological preparation from the fungi of the genus Chaetomium against soil phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum. The inhibitory effect of the preparation under study depended on its concentration, duration of storage, and growth characteristics of pure cultures of the phytopathogens. The highest (98.8%) inhibitory activity was observed on day 3 of the interaction with Rhizoctonia solani. After a 2-year storage, this preparation was capable of inhibiting the growth of the phytopathogens only at high doses. The preparation precluded the development of bare patch and increased the productivity of potato plants. The preparation may serve as an alternative to chemical fungicides for plant protection.     

The effect of a preparation from Chaetomium fungi on the growth of phytopathogenic fungi

We studied the fungicidal activity of a biological preparation from the fungi of the genus Chaetomium against soil phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum. The inhibitory effect of the preparation under study depended on its concentration, duration of storage, and growth characteristics of pure cultures of the phytopathogens. The highest (98.8%) inhibitory activity was observed on the third day of the interaction with Rhizoctonia solani. After a 2-year storage, this preparation was capable of inhibiting the growth of phytopathogens only at high doses. The preparation precluded the development of a bare patch but increased the productivity of potato plants. The preparation may serve as an alternative to chemical fungicides for plant protection.     

Re-thinking the classification of corticioid fungi

Corticioid fungi are basidiomycetes with effused basidiomata, a smooth, merulioid or hydnoid hymenophore, and holobasidia. These fungi used to be classified as a single family, Corticiaceae, but molecular phylogenetic analyses have shown that corticioid fungi are distributed among all major clades within Agaricomycetes. There is a relative consensus concerning the higher order classification of basidiomycetes down to order. This paper presents a phylogenetic classification for corticioid fungi at the family level. Fifty putative families were identified from published phylogenies and preliminary analyses of unpublished sequence data. A dataset with 178 terminal taxa was compiled and subjected to phylogenetic analyses using MP and Bayesian inference. From the analyses, 41 strongly supported and three unsupported clades were identified. These clades are treated as families in a Linnean hierarchical classification and each family is briefly described. Three additional families not covered by the phylogenetic analyses are also included in the classification. All accepted corticioid genera are either referred to one of the families or listed as incertae sedis.     

Glavarioid fungi of the Solomon Islands

Twenty-five species in 13 genera are recorded. New taxa are Clavaria vermicularis Ft. var. latispora var. nov., Clavulinopsis brevipes Corner var. termitarii var. nov., C. fusispora Corner, C. solomonensis Corner, Physalacria solomonensis Corner, Pterula gordyus (Speg.) Corner var. macrospora var. nov., P. robusta Corner, Ramaria solomonensis Corner, R. zippelii (Lév.) Corner var. cristatospora var. nov. (also from Borneo), and Ramariopsis kunzei (Ft.) Donk var. megaspora var. nov. (also from Borneo and Tibet). The clavarioid flora is essentially Malaysian and pantropic.     

DNA methylation in the fungi

A systematic study on the incidence and patterns of cytosine methylation in the fungi has been carried out by restriction and nearest-neighbor analysis of DNAs isolated from undifferentiated cells of several fungal species. With respect to DNA modification, the fungi appear to be a heterogeneous group, with a 5-methylcytosine content ranging from undetectable levels (less than or equal to 0.1% of cytosine residues methylated in 18 out of 20 species tested) to low but detectable levels (e.g. congruent to 0.2 and congruent to 0.5% of the total cytosines methylated in Sporotrichum dimorphosporum and Phycomyces blakesleeanus, respectively). In the species where it has been detected, 5-methylcytosine is located mostly at CpG doublets, and the methylated sites are clustered in long tracts (10-30 kilobase pairs) separated from essentially unmethylated regions. This methylated compartment, which comprises a small fraction (1-11%) of the total DNA, contains at least a specific set of repetitive sequences. These results contrast with the higher 5-methylcytosine content found in the fungus Physarum polycephalum and in vertebrates and higher plants.     

Studies on the physiological bases of morphogenesis in fungi; the respiratory metabolism of dimorphic pathogenic fungi

The interconversions of mycelial and yeast-like forms (M right harpoon over left harpoon Y) in Blastomyces dermatitidis and in Blastomyces brasiliensis are characterized as examples of thermal dimorphism since the phenomena are apparently dependent only on the temperature of incubation of these two species. The change in morphology consequent upon Y --> M conversion is considered to result from the selective inhibition of cell division, without the simultaneous inhibition of growth. Such selective inhibition is viewed in a wider context as an example of the differential operation of the physicochemical apparatus of the cell in the control of form development by an organism. To analyze this differential operation, which is here dependent only on temperature, we have studied the effect of temperature on oxygen consumption by each of the dimorphic forms. In the absence of external substrate the yeast forms consume 5 to 6 times more oxygen per unit dry weight than do the M forms.The Y forms exhibit an exogenous oxidation of acetate and of glucose, as well as an oxidative assimilation of these substrates, whereas the M forms exhibit no exogenous metabolism in either a resting or starved condition. A study of the effect of a wide range of temperatures on oxygen consumption by the M forms indicates the operation of two rate-limiting processes: (a) one with an activation energy of 13,250 calories/gm. molecule over the range 5-30 degrees , and (b) reversible enzyme inactivation; the latter process assuming importance in the higher temperature range. On abrupt, large changes in temperature the balance between these two rate-limiting reactions (which it is suggested characterizes the steady state) is apparently disrupted as a result of a lag in the assumption of a rate of reversible enzyme inactivation characteristic of the new temperature. This disruption of balance is evidenced in overshoot phenomena. The effect of an analogous disruption of balance, and of increasing enzymic inactivation; on a competition between enzyme systems, competing for substrate for cell elongation and for cell division, is considered in explanation of the observed dependence of the cell division mechanism on the maintenance of an elevated temperature.     

发光真菌

本文报道了我国西南地区发光真菌 5属 6种,其中滇丝牛肝菌（Filoboletue yunnanensis P．G．Liu）为我国特有种,粘柄小菇（Mycena glutinipes（Pegler）Sing．）是我国新记录种。