Effect of the products of the vital activity of yeast-like fungi on levorin synthesis

The effect on levorin synthesis of the cells and fermentation broth filtrates of Candida tropicalis after their cultivation in the fermentation medium was studied. It was found that the yeast-like fungi belonging to Candida excreted during their development some products capable of stimulating the synthesis of levorin by 40--60 per cent. When the actinomycete producing levorin was grown on the medium containing 80 per cent of the filtrate the level of levorin synthesis was the same as that observed with mixed cultivation of the actinomycete and C. tropicalis. The study on the conditions providing accumulation of the stimulating substances showed the following: production of the stimulating substances started during the first hours of the yeast growth and reached its maximum by the 48th hour, these substances being consumed by the actinomycete during the fermentation process. Aeration is required for production of the stimulating substances but its high levels are not necessary.     

Bacterial-fungal associations in the intestine under the conditions of colonization by yeast-like fungi of the genus Candida

The composition of the fecal microflora in somatic patients and patients with enteric infections under the conditions of surpluscolonization by yeast-like fungi of the genus Candida was analyzed. The study revealed that the high level of fungal contamination was linked with decreased colonization resistance of the intestine (deficiency in bifidoflora) and with the presence of opportunistic microorganisms: Staphylococcus aureus, hemolytic and lactose-negative Escherichia coli, as well as nonfermenting Gram negative bacteria. The antilysozyme activity of enterobacteria was found to increase in the course of their joint cultivation with fungi of the genus Candida, that may be regarded as one of the mechanisms of the formation and maintenance of pathobiocenosis.     

Effect of cultivation conditions on cellulase activity of higher fungi

Production of cellulases was followed in 4 cultures of higher fungi (Agrocybe cylindracea, Len tinus tigrinus, Pleurotus ostreatus, Ramaria formosa) cultivated on various substrates under different conditions. Stationary cultivation was more suitable than the submerged one. Addition of carboxymethy cellulose (CMC) was more suitable than addition of glucose. The cellulase activity in the presence of CMC was higher after a 12-d cultivation than after a 23-d period. Pine sawdust was most effective of all the substrates tested for the production of cellulases. Beech sawdust and wheat or rye straw were also useful. The addition of yeast autolyzate decreased the production of cellulases. A culture ofL. tigrinud was the best producer.     

Influence of incubation conditions on cell surface hydrophobicity of Candida species fungi

Cell surface hydrophobicity (CSH) is considered to be one of several virulence factors of Candida yeast-like fungi. The aim of the study was a measurment of hydrophobic properties of Candida sp. depending on growth conditions. A total of 139 strains of Candida (80 - C. albicans and 59 - C. non-albicans) were examined. The method of salt aggregation test (SAT) was used. The strains were cultured on three different media, in two variants of incubation temperature and time. The incubation temperature and microbiological medium affected CSH of just C. albicans strains. The influence of incubation time on CSH of examined species of Candida was not occurred. There was a strong correlation between CSH and species of Candida demonstrated in the study Hydrophobic properties were more frequent and stronger among strains of C. non-albicans than C. albicans species. The results of the study indicates that CSH of Candida spp. is a dynamic feature. The ability to change surface properties may play a role in pathogenesis of candidosis.     

Adhesiveness of yeast-like fungi in the system "Candida albicans--vaginal epitheliocytes"

The influence of vaginal liquid on adhesive reactions in the system "Candida albicans - vaginal epitheliocytes". Preliminary treatment of C. albicans by mucin, natural or absorbed vaginal liquid resulted in decrease of adhesive activity (p<0.05). C. albicans did not change its adhesive properties in case of preliminary treatment of vaginal epitheliocytes by the same substances. In the system "Candida albicans - vaginal epitheliocytes" vaginal liquid has the expressed antiadhesive effect, which probably belongs to mucin.     

The characteristics of the ultrastructural changes in yeast-like fungi of the genus Candida exposed to therapeutic-range ultrasound and nystatin]

The electron microscopic study of the ultrastructure of yeast-like fungi of the genus Candida under the action of nystatin and sonication, as well as the action of these two factors used in combination, was carried out. In this study the degree of preservation of the structure of fungal cells was evaluated and the percentage of cells with different ultrastructural changes was determined. Observations made 3 and 24 hours after sonication and treatment with nystatin, used in combination, showed that ultrastructural changes in fungal cells were more pronounced than in the cells subjected to the action of nystatin alone. 24 hours after the combined physico-medicinal treatment of Candida the percentage of nonviable blastospores among them was 5-fold higher than that of such cells among Candida subjected to treatment with nystatin alone and more than 20-fold higher than among Candida subjected only to sonication. These data on the increased fungicidal effect of nystatin used in combination with sonication substantiate the expediency of the above-mentioned physico-medicinal treatment in cases of candidal lesions of the skin and its appendages, which is one of the ways for increasing the effectiveness of the treatment of this mycosis.     

Effect of cultivation conditions on the cytochrome system of Candida mycoderma yeasts

The effect of aeration of the medium, the source of carbon, yeast autolysate and its components (amino acids, vitamins, cytochrome precursors) on the biosynthesis of cytochromes and the ratio between them was studied in the cells of Candida mycoderma. The content of cytochromes b and c increased in the cells at the stationary phase of growth on the Rieder medium regardless of the carbon source and in the presence of elevated concentrations of iron and yeast autolysate (or one of its components, delta-aminolevulinic acid), whereas the content of cytochromes a + a3 decreased. These changes in the content of cytochromes were found in the conditions of strong oxygen deficiency in the medium during the stationary phase.     

Effect of a modifying factor on the sensitivity of Crithidia oncopelti to levorin

The paper deals with possible discovery of ways for increasing sensitivity of trypanosomides to polyenic antibiotics. The following substances were tested: sodium pyruvate and acetate, calcium salts, ascorbic acid and 1-valine. The total number of the cells and the number of the viable cells in the culture and their morphological characteristics were used as the criteria for estimation of the C. oncopelti sensitivity. It was shown that sodium acetate most actively modified the levorin effect on C. oncopelti. Its addition in a concentration of 40 mg/ml to the cultivation medium with levorin in a concentration of 1 microgram/ml induced a trypanocidal effect. With the use of levorin alone such an effect was observed when the antibiotic was used in a concentration of 10 micrograms/ml. The growth rate of the protozoon was decreased by 60-80 per cent as compared to the control. The number of the viable cells was lowered 4 times. The morphology of the culture markedly changed. This indicates that the presence of sodium acetate as a modifier in the culture medium allowed one to decrease 10 times the dose of levorin and to preserve the trypanocidal effect.     

Action of levorin on amino acid transport in Candida albicans]

It was shown that suppression by levorin of the leucine transport into the cells of C. albicans was due to replacement of intracellular K+ by Na+ induced by the antibiotic. The alanine transport was suppressed by levorin irrespective of the ratio of the monovalent cations concentration in the medium and inside the cell. The levorin effect on the protone escape from the cells was negligible and probably played no significant role in the mechanism of the amino acid transport suppression by the antibiotic.     

妇科住院患者酵母样真菌感染的菌株分布与药敏研究

目的对妇科住院患者阴道分泌物酵母样真菌隐性感染的菌群分布与药敏结果进行回顾性分析,为临床围手术期合理使用抗真菌药物提供依据。方法妇科住院患者5813例阴道分泌物中分离到396株酵母样真菌,采用API-20Aux和ATBFUNGUS进行鉴定和药敏试验。结果396株酵母样真菌中,分离率最高的前3位是白色假丝酵母菌（59.6%）、光滑假丝酵母菌（21.2%）和接合假丝酵母菌（6.6%）。酵母样真菌对5-氟胞嘧啶（5-FC）、两性霉素B（AMB）和制霉菌素（NYS）敏感率最高,达90.7%、92.7%和96.2%,咪康唑（MIC）、益康唑（ECO）和酮康唑（KET）分别为74.2%、61.6%和69.4%。结论住院妇科患者阴道分泌物酵母样真菌隐性感染主要以白色念珠菌和光滑念珠菌为主,感染的酵母样真菌对5-FC、AMB和NYS的药物敏感性较高,对唑类抗真菌药则有不同程度的耐药率。     

Use of the coagglutination reaction of yeast-like Candida maltosa fungi for detecting fimbriae in intestinal bacteria

The capacity of nonpathogenic yeast-like C. maltosa strains to coagglutinate Escherichia coli has been studied. C. maltosa cells have also been shown to coagglutinate E. coli possessing mannose-sensitive adhesins in a wide range of their concentrations (5-140 bacterial cells per C. maltosa cell). Strains belonging to types CFA/I and CFA/II with fimbriae, similarly to their corresponding paired genetically related strains without these adhesins, are practically incapable of agglutinating C. maltosa cells, while strains K88 and B41 react with them. The reaction occurs at a concentration of 9.5-37.0 and 38.0-55.5 bacteria respectively per C. maltosa cell and is not inhibited by 1% d-mannose. The suggestion that C. maltosa cell surface glycoproteins contain not only receptors for E. coli fimbriae, type I, but also components similar in their structure to receptors specific to the mannose-resistant adhesins of strains K88, K99 and 41, has been confirmed by hemagglutination inhibition with C. maltosa surface antigens as inhibiting agents.