Fungi from decaying intertidal fronds of Nypa fruticans, including three new genera and four new species

HYDE, K. D., 1992. Fungi from decaying fronds of Nypa fruticans, including three new genera and four new species. Decaying fronds and exposed stems of the mangrove palm Nypa fruticans were collected from beaches and intertidal regions of mangroves in Brunei and examined for the presence of higher marine fungi. Forty-three species were identified, four of which are new to science. The fungi included 32 Ascomycotina, one Basidiomycotina and ten Deuteromycotina. Three new genera and four new species are described and illustrated.     

Biodiversity amongst filamentous fungi

Diversities in fungi are manifold. Fungi themselves are heterogeneous and constitute at least three unrelated major taxa. Structural diversity reflects, in most cases, adaptive and functional strategies. Diversity in nucleic acids and chemical compounds is very high in several fungal taxa. Fungi play an essential role in the function of ecosystems. The diversity of plant parasites is extremely high and species-dependent associations exist. Saprobic fungi are most important in wood and litter decay and diverse taxa comprise the main decomposers in specific successional niches. Two dominating symbiotic systems have evolved convergently in various fungal groups, notably lichens and mycorrhizas, both remarkably diverse in their heterotrophic partners.     

Production of cellulolytic enzymes from theXylaria andHypoxylon species of xylariaceae

Eighteen strains of xylariaceous fungi have been screened for higher activities of cellulolytic enzymes,Trichoderma reesei QM 9414 was also examined for comparison. Strains ofXylaria anisopleura andX. regalis had higher endocellulase (CMCase) and exocellulase (Avicelase) activities after 2 weeks' incubation.Hypoxylon stygium produced the highest activity of -glucosidase 3 days after inoculation. The optimum pH for these cellulolytic enzymes was approx. 5.0 and the optimum temperatures ranged from 37 to 50°C. A mixed culture process usingT. reesei QM 9414 andH. stygium was developed to obtain enhanced synthesis of cellulase. -Glucosidase activities in the mixed culture increased within 48h whenH. stygium was introduced after 24h.     

广西森林土壤丝状真菌的生态分布

真菌种类多,分布广,对人类的生产和生活关系非常密切,因此近来对真菌特别是丝状真菌的研究日益引起高度重视。1981—1990年我们对桂北龙胜县里骆林区、桂中宜山县庆远林区、桂南岑溪县七坪林区和桂西田林县老山林区森林土壤微生物区系进行了分析,其中丝状真菌是我们重点研究的内容之一。在上述森林土壤中共分离出丝状真菌2084株,经鉴定归属于25属。现将广西森林土壤丝状真菌生态分布的研究结果报道如下。     

Keratinolysis by Absidia cylindrospora and Rhizomucor pusillus: biochemical proof

Absidia cylindrospora and Rhizomucor pusillus, causal agents of phycomycoses, were cultured on sterile natural keratins in a mineral solution and the keratin degradation products analyzed. The excess of sulphur was removed by oxidation to inorganic sulphate and thiosulphate, which were the main products of sulphitolysis of keratin. The proteolytic activity of the two fungi depended on the nature of the keratin substrate. Human scalp hair was the most favoured keratin substrate by both the fungi.     

Characterization of a novel microsomal glutathione S-transferase produced by Aspergillus ochraceus TS

Purification and characterization of microsomal glutathione S-transferase produced by Aspergillus ochraceus TS are reported. The isozymes are located in microsomes and were active against 1-chloro-2,4-dinitrobenzene, ethacrynic acid, 1,2-dichloro-4-nitrobenzene, trans-4- phenyl-3-buten-2-one,p-nitrobenzyl chloride and bromosulphophthalein. They were inhibited by N-ethylmaleimide and bromosulphophthalein. The GST isozymes produced by Aspergillus ochraceus TS are indistinguishable in respect of their molecular mass both in native and denatured state. The subunit of the purified protein had an apparent M_r of 11 kDa while molecular mass of the native protein is around 56 kDa. The substrate specificity and pl values of the isozymes were different. The GSTs produced by Aspergillus ochraceus TS fairly share functional properties with mammalian cytosolic isozymes.     

Epidemiology of allergic disease: the fungi

Summary In indoor aerial environments and in particular that of homes, the number and type of fungal spores present in the air depend, more than on air exchange with the outside atmosphere, on the presence of sources or dispersion within the building itself. The concentration of spores is half that normally recorded outside the building, withAspergillus, Penicillium, Cladosporium, Alternaria, Mucor, Rhizopus andOidiodendron as the dominating genera. Aerosporological investigations carried out in homes should ideally be done at night, with the exposition of cultural dishes. The repetitive isolation of the same fungus may be particularly important in the etiology of allergic manifestation in man. Particular environments, if insufficiently aerated, with high levels of relative humidity and insufficient illumination, may become ecological niches particularly well suited to fungi, both during its latent form or during a phase of rapid development. Together with rapidly developing fungi, for instanceMucor andRhizopus, slow developing moulds such asPenicillium, Aspergillus andTrichoderma may also be found, characterized however by a production of a great number of easily dispersed conidia. Etiological research into the allergic manifestations of patients continuously inhaling spores responsible for particular allergies appears to be insufficiently developed.     

The vacuolar ATPase ofNeurospora crassa

The filamentous fungusNeurospora crassa has many small vacuoles which, like mammalian lysosomes, contain hydrolytic enzymes. They also store large amounts of phosphate and basic amino acids. To generate an acidic interior and to drive the transport of small molecules, the vacuolar membranes are densely studded with a proton-pumping ATPase. The vacuolar ATPase is a large enzyme, composed of 8–10 subunits. These subunits are arranged into two sectors, a complex of peripheral subunits called V₁ and an integral membrane complex called V₀. Genes encoding three of the subunits have been isolated.vma-1 andvma-2 encode polypeptides homologous to the and subunits of F-type ATPases. These subunits appear to contain the sites of ATP binding and hydrolysis.vma-3 encodes a highly hydrophobic polypeptide homologous to the proteolipid subunit of vacuolar ATPases from other organisms. This subunit may form part of the proton-containing pathway through the membrane. We have examined the structures of the genes and attempted to inactivate them.     

Impact of salinity stress on soil-borne fungi of sugarbeet

The sugarbeet cultivar Kaumera was found to be highly susceptible to infection by the root-rot pathogens Rhizoctonia solani and Sclerotium rolfsii in the absence of salinity stress. Under this environmental condition, R. solani was more efficient than S. rolfsii in producing cell wall-degrading enzymes in infected hypocotyls. Xylanase and galactanase were most effective. The rate of cell wall degradation by R. solani was nearly 2.5 times that of S. rolfsii when cells walls of healthy hypocotyls were used as sole carbon substrate for the in vitro produced crude enzymes.Under salinity stress the pathogenicity and the performance of cell wall-degrading enzymes of R. solani and S. rolfsii varied profoundly. Pathogenicity studies showed that R. solani appeared to be more tolerant than S. rolfsii of the salinity stresses applied, and relatively more virulent to cv Kaumera. The activities of cell wall enzymes of R. solani decreased and those of S. rolfsii increased with increased salt concentration when cell wall material was used as a sole carbon source. The metabolic products produced under salinity stress by R. solani and R. solani in the cell wall amended culture media shifted the initial pH towards neutrality or slight alkalinity for R. solani and to high acidity for S. rolfsii.When model substrates were used, xyland and galactan were the most responsive substrates for degradation by the cell wall enzymes of the two fungi studied. The rate of degradation was higher for S. rolfsii than for R. solani. The excessive acidity in salt stressed S. rolfsii culture media suggested reduced activities of the enzymes involved in cell wall degradation in vivo. This may explain the decreased virulence potentialities.