Effect of the cultivation conditions of Candida species yeast-like fungi on their sensitivity to levorin]

The effect of levorin on yeast-like fungi under (different) cultivation conditions was studied. It was shown that the medium composition and incubation temperature affected the results of determination of the test-culture sensitivity to levorin. There was correlation between the time of the population lag-phase and the critical time of the zone formation and these values depended on the temperature of the test-microbe vegetation. Strain 037 of C. utilis was more sensitive to levorin and had a longer lag-phase as compared to the other species of the yeast-like fungi, which provided favourable conditions for formation of the growth inhibition zones.     

Action of the products of the vital activity of yeastlike fungi on the biosynthesis of levorin, levoristatin and fatty acids by a Streptomyces levoris culture

The data on the effect of the products of vital activity of Candida tropicalis, a yeast-like fungus, on the biosynthesis of levorin, levoristatin and fatty acids by Streptomyces levoris are presented. It was shown that the effect of the biostimulators was not specific with respect to production of levorin, since in the presence of the products of vital activity of C. tropicalis an increase in the synthesis of levoristatin and fatty acids was also observed. The qualitative and quantitative composition of the fatty acids of the mycelium of S. levoris was studied. Interrelation between the biosynthesis of levorin and synthesis of unsaturated fatty acids and branched chain fatty acids was noted.     

Nature of the stimulating substances found in the vital activity products of yeastlike fungi

The cultural broth of Candida tropicalis was shown to contain an active compound which stimulated the synthesis of levorin, a polyene antibiotic Succinic acid was found to stimulate the antibiotic synthesis. The stimulating effect of the active compound increased in proportion to the content of succinic acid in it and became maximal at the same concentration of succinic acid as in a pure preparation. However, succinic acid was not an only compound responsible for the elevated synthesis of the antibiotic since the biostimulating effect was higher than that of pure succinic acid.     

Effect of various microorganisms on the activity of levorin

Levorin added to nutrient media with growing cultures of aerobic gram-positive bacilli, Escherichia, enterococci and filamentous fungi was partially inactivated. The antibiotic activity decrease depended on the strain characteristics, incubation period and temperature. Fermentation broth filtrates of the experimental strains also inactivated levorin while to a lesser extent than the growing organisms. In contaminated levorin pastes, the antibiotic activity was lower. The fermentative nature of inactivation was not proved.     

The taxonomy of the anascosporous yeast-like fungi

Conclusion The species of yeast-like anascosporogenous fungi most frequently isolated from man were found to be the following: albicans, tropicalis, pseudotropicalis, Krusei, parakrusei, stellatoidea and Guilliermondi. A restudy of old cultures maintained in culture bureaus for long periods of time has allowed investigators to add other species to this list. These old cultures, representing single isolations, were thought to be partially dissociated because both rough and smooth colonies developed on blood agar plates at 37°C. when streaked from Sabouraud's glucose broth. When the smooth colony was picked for study, the culture could be identified as one of the most frequently isolated species.The rough colonies, however, showed certain differences which allowed them to be classified as distinct species. To avoid characterizing new species on the basis of dissociative changes, freshly isolated cultures should be identified immediately by some rigidly standardized technique giving constant results.A single genus, to be used internationally, has been proposed for these fungi which were obviously too closely related to be separated generically. Since Syringospora Quinquaud 1868 was the first validly published genus, it can be replaced by a more recently published genus only by establishing the latter as a nomen conservandum with appropriate emendation and the selection of the proper type species.1. Presented at the Third International Congress for Microbiology, Sept. 2–9, 1939, New-York, New-York.Aided by a grant from the John and Mary R. Markle Foundation.     

Mycocinogeny in smut yeast-like fungi of the genus Pseudozyma

The fungistatic agent secreted by Pseudozyma prolifica VKM Y-2835 shows activity against some representatives of the Ustilaginales under acidic conditions. This mycocin, with a molecular mass of no less than 15 kDa, is thermolabile and sensitive to proteolytic cleavage.     

Reactivity of human lymphocytes to yeast-like and mold fungi

The capacity of the allergens of mold fungi (Rhizopus nigricans, Mucor pusillus, Alternaria tenuis, Cladosporum herbarum, Fusarium oxysporum) and yeast-like fungi (Candida albicans) to induce the production of lymphokins by human lymphocytes was studied. All these preparations were active in reactions with lymphocytes obtained from adult donors, but did not activate lymphocytes of newborns (obtained from umbilical blood). In equal doses (10 micrograms/ml) C. albicans allergen was more active than the preparations of mold fungi. The capacity of bacterial allergens to stimulate human lymphocytes was found to be either more pronounced (in Staphylococcus aureus, Streptococcus pyogenes) than that of the preparation of C. albicans or equal to it (in Streptococcus faecalis). The results thus obtained may be regarded as the manifestation of immunological contacts with the antigens of different microorganisms, as well as the evidence of the immunological nature of lymphocytic reactions to preparations intended for use in clinical allergology.     

Carbon assimilation and extracellular antigens of some yeast-like fungi

Many yeast-like fungi assimilated n-hexadecane, butylamine and putrescine as sole carbon sources. Methanol was not assimilated. This points to a physiological similarity to endomycetous, hydrocarbon-utilizing yeasts. Stephanoascus ciferrii assimilated uric acid, adenine and allantoin as sole source of carbon and nitrogen. All strains of Geotrichum candidum and many other yeast-like fungi assimilated acetoin and butan-2,3-diol. Assimilation tests for adenine, uric acid, allantoin, acetoin and butan-2,3-diol were found to be suitable for taxonomic purposes.Extracellular antigens immunologically related to those produced by Geotrichum candidum were detected in the cell-free culture liquids of several yeast-like fungi. The extracellular antigen excreted by Stephanoascus ciferrii was species-specific.     

临床酵母样真菌的感染特点及耐药性研究

目的了解临床酵母样真菌的感染类型、分布以及耐药情况,为临床诊断治疗提供合理的用药依据.方法采用常规方法进行真菌培养,用科玛嘉显色培养基联合法国生物梅里埃API 20C AUX鉴定条进行鉴定,药敏试验采用微量稀释法.结果864株酵母样真菌中,白色念珠菌619株（71.6%）,其次为热带念珠菌116株（13.4%）和克柔念珠菌47株（5.4%）,非白色念珠菌感染的比例逐年上升（21.5%）.其中,呼吸道标本酵母样真菌检出率最高,达79.7%,其次是消化道为8.8%,泌尿道为4.7%.科室分布依次为干部科、呼吸科、急诊内科、血液科等;白色念珠菌对两性霉素B、5-氟胞嘧啶高度敏感,达90%以上,对氟康唑和伊曲康唑的敏感性有所降低.结论酵母样真菌的检出率与患者基础疾病密切相关;对氟康唑等药物的敏感性有下降的趋势,未发现对4种药物同时耐药的菌株,提示在治疗中,药敏监测是非常必要的.