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.     

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.     

Production of antibacterial compounds by phylloplane-inhabiting yeasts and yeastlike fungi.

The production of antibacterial compounds by yeasts and yeastlike fungi isolated from the phylloplane is reported. Aureobasidium pullulans, Citeromyces matritensis, Cryptococcus laurentii, Rhodotorula glutinis, and Sporobolomyces roseus produced antibacterial compounds inhibitory to both Pseudomonas fluorescens and Staphylococcus aureus in an overlay bioassay. In contrast, isolates of Candida albicans, Filobasidium uniguttulatum, Saccharomyces cerevisiae, Torulaspora delbruckii, Tremella foliacea, Trichosporon beigelii, and Trichosporon dulcitum obtained from soil or from culture collections did not produce inhibitory compounds when screened by the same procedure. The production of antibacterial compounds was examined in more detail, using several isolates of A. pullulans distinguished by cluster analysis on the basis of biochemical and physiological tests. They were found to produce a range of antibacterial compounds with different activities. Two distinct antibiotics were produced by an isolate of A. pullulans in liquid culture during both the logarithmic and the stationary phases of growth.     

MTT比色法测定促肝细胞生长物质对肝细胞生长的刺激活性

本实验建立了用简便的ＭＴＴ比色法对促肝细胞生长物质的促肝细胞增殖作用的测定方法,确定了实验的最适条件。与传统的３Ｈ ＴｄＲ掺入法进行比较的结果显示,ＭＴＴ比色法与３Ｈ ＴｄＲ掺入法测定结果基本相符,灵敏度相近,但消除了同位素的污染,是一个测定促肝细胞生长物质刺激肝细胞增殖活性的简便方法。     

Detection of biologically active substances with antagonistic and stimulating activity in Spirulina platensis

The results of studies on the detection of biologically active substances (BAS) in biomass dilutions and culture fluid of Spirulina platensi and algae (Chlorella, Fucus, Laminaria) by the agar diffusion method are presented. After the sterilization of the solutions with chloroform (CF) a substance with lysozyme-like activity and 2 substances with antagonistic activity deep in agar and on its surface were detected with the use of the micrococcal indicator strain. After CF treatment, depending on the concentration of S. platensis strains, a compound stimulating the growth of bacteria and sensitive to heat treatment was detected. BAS were also detected with the use of other indicator cultures.     

Catabolism of benzene compounds by ascomycetous and basidiomycetous yeasts and yeastlike fungi

A literature review is given on growth of yeasts on benzene compounds and on the catabolic pathways involved. Additionally, a yeast collection was screened for assimilation of phenol and 3-hydroxybenzoic acid. Fifteen ascomycetous and thirteen basidiomycetous yeast species were selected and were tested for growth on 84 benzene compounds. It appeared that 63 of these compounds supported growth of one or more yeast species. The black yeastExophiala jeanselmei assimilated 54 of these compounds.The catechol branch of the 3-oxoadipate pathway and its hydroxyhydroquinone variant were involved in phenol and resorcinol catabolism of ascomycetes as well as of basidiomycetes. However, these two groups of yeasts showed characteristic differences in hydroxybenzoate catabolism. In the yeastlike fungusE. jeanselmei and in basidiomycetes of the generaCryptococcus, Leucosporidium andRhodotorula, the protocatechuate branch of the 3-oxoadipate pathway was induced by growth on 3- and 4-hydroxybenzoic acids. In threeTrichosporon species and in all ascomycetous yeasts tested, 4-hydroxybenzoic acid was catabolyzed via protocatechuate and hydroxyhydroquinone. These yeasts were unable to cleave protocatechuate. 3-Hydroxybenzoic and 3-hydroxycinnamic acids were catabolized in ascomycetous yeasts via the gentisate pathway, but in basidiomycetes via protocatechuate.Incomplete oxidation of phenol, some chlorophenols, cresols and xylenols was observed in cultures ofCandida parapsilosis growing on hydroquinone. Most compounds transformed by the growing culture were also converted by the phenol monooxygenase present in cell-free extracts of this yeast. They did not support growth.The relationship between the ability of ascomycetous yeasts to assimilate n-alkanes, amines and benzene compounds, and the presence of Coenzyme Q₉ is discussed.     

Biodegradation of tetrabromobisphenol A by oxidases in basidiomycetous fungi and estrogenic activity of the biotransformation products

Tetrabromobisphenol A (TBBPA) degradation was investigated using white rot fungi and their oxidative enzymes. Strains of the Trametes, Pleurotus, Bjerkandera and Dichomitus genera eliminated almost 1 mM TBBPA within 4 days. Laccase, whose role in TBBPA degradation was demonstrated in fungal cultures, was applied to TBBPA degradation alone and in combination with cellobiose dehydrogenase from Sclerotium rolfsii. Purified laccase from Trametes versicolor degraded approximately 2 mM TBBPA within 5 h, while the addition of cellobiose dehydrogenase increased the degradation rate to almost 2.5 mM within 3 h. Laccase was used to prepare TBBPA metabolites 2,6-dibromo-4-(2-hydroxypropane-2-yl) phenol (1), 2,6-dibromo-4-(2-methoxypropane-2-yl) phenol (2) and 1-(3,5-dibromo-4-hydroxyphen-1-yl)-2,2',6,6'-tetrabromo-4,4'-isopropylidene diphenol (3). As compounds 1 and 3 were identical to the TBBPA metabolites prepared by using rat and human liver fractions (Zalko et al., 2006), laccase can provide a simple means of preparing these metabolites for toxicity studies. Products 1 and 2 exhibited estrogenic effects, unlike TBBPA, but lower cell toxicity.     

The effect of vital activity products of hydrophilic birds and the degree of overgrowth on zooplankton in experimental microcosms

Experiments conducted in microcosms at different concentrations of vital activity products of hydrophilic birds (VAPBs) and the degree of overgrowth revealed basic changes in the chemical composition of the water parameters of the zooplankton. It is shown that the input of VAPBs over a period of time close to the natural nesting period leads to an increase in concentration of organic compounds in water, the diversity of crustaceans, and the total abundance and biomass of communities due to Copepoda (the portion of which also increases among dominants upon a decrease of Rotifera). Along with an increase in the degree of over-growth of microcosms subjected to the effect of VAPBs, the quantitative parameters of Rotifera development decrease and the abundance and biomass of communities increases due to Cladocera.     

Investigation into the production of bacteriostatic substances by fungi

A method is suggested for estimating the degree of potency and, to some extent, the specificity of bacteriostatic substances produced by fungi. It is based on the examination of several hundred fungi over a period of 2 years. It consists essentially of the placing of a few drops of the substance to be tested in the centre of a plate of bacteria-incorporated agar with the consequent production of a zone of inhibition which varies in width in proportion to the concentration of the bacteriostatic substance. The test is made against two representative types of bacteria— Bact. coli and Staph, aureus. The permissible technical latitude in the application of the test has been summarized. By using a standard inhibitor (mercuric chloride) the accuracy of the method has been statistically proved. This 'zonation' method has been compared with the standard 'dilution' method and close correlation has been established.     

Use of substances stimulating enterobacteria growth in obtaining microbial adsorbents

The combination of substances, capable of stimulating the growth of enterobacteria and consisting of reducing agents (sodium thiosulfate and sodium sulfate), the vitamin preparation of yeast extract, polyatomic alcohol (glycerol) and ion exchange resin AB-17-8, is proposed. The addition of this combination of substances to culture media based on clots of animal blood has made it possible to achieve more intensive growth of Escherichia and Proteus than on classical meat culture media.     

Biosynthesis of galactomannans found in filamentous fungi belonging to Pezizomycotina

The galactomannans (GMs) that are produced by filamentous fungi belonging to Pezizomycotina, many of which are pathogenic for animals and plants, are polysaccharides consisting of α-(1→2)-/α-(1→6)-mannosyl and β-(1→5)-/β-(1→6)-galactofuranosyl residues. GMs are located at the outermost layer of the cell wall. When a pathogenic fungus infects a host, its cell surface must be in contact with the host. The GMs on the cell surface may be involved in the infection mechanism of a pathogenic fungus or the defense mechanism of a host. There are two types of GMs in filamentous fungi, fungal-type galactomannans and O-mannose type galactomannans. Recent biochemical and genetic advances have facilitated a better understanding of the biosynthesis of both types. This review summarizes our current information on their biosynthesis.