Extracellular Tremella polysaccharides: structure, properties and applications

Tremella sp. is a yeast-like fungus from which polysaccharides can be isolated from either the yeast or the fungus phase, depending on the species. All of the polymers synthesized by these organisms consist of a mannan backbone to which small xylose side chains and glucuronic acid are attached. The main interest in these glucuronoxylomannans is their application in medicine to enhance the immune system.     

Tremella occultifuroidea sp. nov., a new mycoparasite ofDacrymyces

Tremella occultifuroidea, a new parasite of dacrymycetaceous fungi is described. It differs from knownTremella parasites in dacrymycetaceous hosts by thick-walled dikaryotic conidia, terminally and repeatedly originating from conidiogenous cells, thus resembling those ofT. polyporina by Koske,T. obscura by Christiansen andOccultifur internus. Part of 167 of a series “Studies in Heterobasidiomycetes” of Tübingen University.     

银耳及其伴生菌营养生理生态研究

本文分析了银耳与其伴生菌在木屑培养基和废棉渣培养基上生长期间,栽培基质中主要成分的降解规律及其有关的酶学基础。试图从营养生理角度探讨银耳与其伴生菌之间的生态关系。实验结果表明,银耳菌单独在木质纤维素上生长时,不能形成子实体。当银耳与伴生菌生长在一起时,银耳菌在木质纤维废物上生长发育良好,可形成子实体。银耳子实体生长对培养基中的纤维素降解有促进作用。     

Tremella macrobasidiata and Tremella variae have abundant and widespread yeast stages in Lecanora lichens

Dimorphism is a widespread feature of tremellalean fungi in general, but a little-studied aspect of the biology of lichen-associated Tremella. We show that Tremella macrobasidiata and Tremella variae have an abundant and widespread yeast stage in their life cycles that occurs in Lecanora lichens. Their sexual filamentous stage is restricted to a specific lichen: T. macrobasidiata only forms basidiomata on Lecanora chlarotera hymenia and T. variae only on Lecanora varia thalli. However, the yeast stage of T. macrobasidiata is less specific and can occur in L. varia lichens, whilst all life stages of T. variae may be specific to L. varia. Contrary to the hyphal stages, the yeasts are distributed across the thalli and hymenia of Lecanora lichens, and not limited to specimens with basidiomata. Tremella macrobasidiata was present in all studied L. chlarotera, and in 59% of L. varia specimens. Only in 8% of the L. varia thalli could none of the two Tremella species be detected. Our results indicate that lichen-associated Tremella may be much more abundant and widespread than previously assumed leading to skewed estimations about their distribution ranges and lichen specificity, and raise new questions about their biology, ecology and function in the symbiosis.     

Leaf volatiles from Thymus vulgaris, T. serpyllum, T. praecox, T. pulegioides and T. x citriodorus (Labiatae)

Wound–emitted leaf volatiles in soe species of Thymus were analysed. Fresh shoots without flowers were used. The volatiles were isolated by adsorption on a porous polymer (Tenax GC). The emitted components were separated by a capillary gas chromatograph modified to give reproducible retention time values. The identifications are based on mass spectra and retention time values of reference compounds. The results indicate the mildness of the method used. This is one part of the methodological work of an investigation concerning the biochemical background of pest and disease resistance in plants. Attention is drawn to the urgent need in resistance breeding for a taxonomic survey of the intraspecific allelochemic multitude.     

Cultivation in a semi-defined medium of animal infective forms of Trypanosoma brucei, T. equiperdum, T. evansi, T. rhodesiense and T. gambiense.

A semi-defined medium for the cultivation of bloodstream forms of the African trypanosome brucei subgroup was developed. Out of 14 different strains tested, 10 could be cultured including Trypanosoma brucei, T. equiperdum, T. evansi, T. rhodesiense and T. gambiense. The presence of a reducing agent (2-mercaptoethanol or thioglycerol) was found to be essential for growth. The standard medium consisted of Hepes buffered minimum essential medium with Earle's salts supplemented with 0.2 mM 2-mercaptoethanol, 2 mM pyruvate and 10% inactivated serum either from rabbit (T. brucei, T. equiperdum, T. evansi and T. rhodesiense) or human (T. gambiense). Although a general medium could be defined for the long-term maintenance of trypanosome cultures, the initiation to culture nevertheless required particular conditions for the different strains. The cultured trypanosomes had all the characteristics of the in vivo bloodstream forms including: morphology, infectivity, antigenic variation and glucose metabolism.     

Genome constitutions of Thinopyrum curvifolium, T. scirpeum, T. distichum, and T. junceum (Triticeae: Gramineae).

The objective of this study is to elucidate genome constitutions of Thinopyrum curvifolium (Lange) D.R. Dewey, T. scirpeum (K. Presl) D.R. Dewey, T. distichum (Thunb.) A. L?ve, and T. junceum (L.) A. L?ve. Hybrids of T. sartorii (Boiss. &Heidr.) A. L?ve with T. scirpeum and T. junceum, as well as the hybrid between T. curvifolium and Pseudoroegneria geniculata ssp. scythica (Nevski) A. L?ve, were made and chromosome pairing at metaphase I was studied. The karyotype analyses of mitotic cells stained by aceto-orcein were conducted for both hybrids and the four target species. The Giemsa C-banding following acetocarmine staining was carried out for the above species and the triploid hybrid T. curvifolium x T. bessarabicum (Savul &Rayss) A. L?ve. Meiotic data indicate that all target species have two sets of the basic genome J, but they behave like true allopolyploids because of bivalentization. Karyotypes of T. curvifolium and its triploid hybrid with T. bessarabicum indicate that T. curvifolium contains two different versions of the Jb genome, designated as Jb3 and Jb4, rather than two Je genomes as previously believed. Thinopyrum scirpeum and T. elongatum (4x) have similar karyotypes. Both are segmental allotetraploids carrying two forms of the Je genome. Their genome formulae are Je2 Je3 and Je1 Je3, respectively. Thinopyrum distichum has a karyotype similar to T. junceiforme, which has the Jb2 Je2 genome formula. However, the two species differ in C-banding patterns, reflecting their geographical separation. Thinopyrum junceum is a hexaploid with two pairs of Jb2 genomes and one pair of the Je2 genome, and it has a C-banding pattern similar to that of T. junceiforme, which has one pair each of the Jb2 and Je2 genomes.     

Fc receptors on human T lymphocytes. II. Cytotoxic capabilities of human T gamma, T mu, B, and L cells.

Subpopulations of human peripheral blood lymphocytes were prepared by rosetting techniques employing neuraminidase-treated sheep erythrocytes (SRBC_n), sheep erythrocytes coated with IgM and murine complement (EAC′), and bovine erythrocytes coated with IgG and IgM. The isolated subpopulations were tested in assays of natural cytotoxicity (NC), antibody-dependent cellular cytotoxicity (ADCC), and mitogen-induced cellular cytotoxicity (MICC). B cells (SRBC_n?, EAC′+) did not mediate cytotoxicity. L cells (SRBC_n?, EAC′?) mediated NC and ADCC but not MICC. T cells (SRBC_n+) mediated NC, ADCC, and MICC. Separation of T cells into Fc-IgG (Tγ) and Fc-IgM (Tμ) subsets revealed that Tγ cells mediated NC, ADCC, and MICC while Tμ cells mediated only MICC. Thus MICC but not NC or ADCC was solely T-cell mediated. Tγ and L cells were functionally distinguishable in that Tγ cells but not L cells mediated MICC. Tγ cells and Tμ cells differed with regard to NC and ADCC effector function while both subsets mediated MICC.