[Natural foci of leptospirosis on the territory of Moscow in 1995 - 2004].

The results of ten-year observations of the natural foci of leptospirosis on the territory of Moscow are presented. Information on the foci, the main species of small mammals (the reservours of the infection), the etiological structure of leptospires, circulating among rodents and insectivores, is given.

[Rodents as the vectors of infective agents in the natural foci of infections in the Moscow megapolis].

This work deals with the results of 40-year observations on the circulation of infective agents in the natural foci of infections (tularemia, leptospirosis, hemorrhagic fever with renal syndrome) among rodents and other small mammals in the territory of the Moscow. The monitoring of their frequency and the infection rates remains the main effective measure for the prophylaxis of dangerous infections among the population of the megapolis.

[Natural foci of leptospirosis in Moscow in 1995 - 2004].

The article deals with the results of the 10-year study of the synanthropic urban foci of leptospirosis on the territory of Moscow. Information on the manifestation of the activity of the foci under study, rodents serving as the reservoir of infection in these foci, the etiological structure of the leptospires among these rodents, the state of leptospirosis morbidity among humans is presented.

[Yeast resistance to polyene antibiotics. III. Phenotypic analysis of polyene-resistant sterol mutants of Saccharomyces cerevisiae yeasts]. / Rezistentnost' drozhzhei k polienovym antibiotikam. Soobshchenie III. Femotipicheskii analiz polienrezistentnykh sterinovykh mutantov drozhzhei Saccharomyces cerevisiae.

The pleiotropic effects of nystatin resistant mutations have been studied. It has been shown that resistance to nystatin is often accompanied by temperature-sensitivity and, in some cases, by osmotic remedial sensitivity. The dependence of the expression of the mutations on temperature is demonstrated. A new type of conditional nystatin-dependent mutants is found. All nys2 mutants have a defected membrane and are stained on a methylene blue containing media. At the same time, the mutations under investigation do not affect the respiratory competence and the exoenzyme activity of acid phosphatases.

[Characteristics of the range of mutations in nystatin resistance induced in yeasts by 6-N-hydroxylaminopurine]. / Osobennosti spektra mutatsii nistatinustoichivosti, indutsirovannykh u drozhzhei 6-N-gidroksilaminopurinom.

A simple procedure for induction of nistatin-resistant mutants in yeasts under the action of 6-N-hydroxylaminopurine (HAP) is proposed. Some differences between the spectra of mutations induced by HAP and UV-light are observed: HAP induces dominant and double recessive mutants more frequently.

[Yeast resistance to polyene antibiotics. II. An analysis of the sterol composition of Saccharomyces cerevisiae yeasts resistant to nystatin]. / Rezistentnost' drozhzhei k polienovym antibiotikam. Soobshchenie II. Analiz sostava sterinov u drozhzhei Saccharomyces cerevisiae, ustoichivykh k nistatinu.

The recessive yeast mutations nys providing resistance to polyene antibiotics in Saccharomyces cerevisiae are described. The analysis of UV-absorbtion spectra of sterols from cells of different mutants allows to assume that NYS genes control synthesis of ergosterol. The lack of alterations in the sterol composition of the same strains carrying dominant nystatin resistance mutations points to the existence of another mechanisms of resistance to polyene antibiotics, in addition to the sterol mechanism.

[Yeast resistance to polyene antibiotics. IV. A study of the inheritance of changes in the sterol composition of Saccharomyces cerevisiae yeasts caused by mutations of nystatin resistance]. / Rezistentnost' drozhzhei k polienovym antibiotikam. Soobshchenie IV. Izuchenie nasledovaniia izmenenii v sostave sterinov, obuslovlennykh mutatsii ustoichivosti k nistatinu u drozhzhei Saccharomyces cerevisiae.

Sterol content in haploid and diploid strains of yeast having mutations of resistance to nystatin were studied by UV spectrometry method. Heterozygous diploids carrying one or two nystatin resistance mutations have, as a rule, the sterol content of the wild type strains. Segregants of the same genotype demonstrate differences in sterol content. Double mutants nys1 nys2 and nys1 nys3 have UV spectra typical for single nys2 and nys3 mutants, respectively. Double mutants nys1 nysX are characterized by a "mixed" UV spectra of sterols.

[Sterol composition in yeast strains sensitive and resistant to nystatin]. / Sostav stearinov u shtammov drozhzhei, chuvstvitel'nykh i ustoichivykh k nistatinu.

The sterol composition of nystatin-sensitive and nystatin-resistant strains of Saccharomyces cerevisiae was being studied by gas-liquid chromatography and mass-spectroscopy. The synthesis of ergosterol is completely suppressed in polyene-resistant mutants. Three sterols derived from cholesterol were identified in the mutants: cholesta-8,24-diene-3 beta-ol, cholesta-5,7,24-triene-3 beta-ol, and cholesta-5,7,22,24-tetraene-3 beta-ol.