No abstract

Streptomyces albidoflavus J1074 is a popular platform to discover novel natural products via the expression of heterologous biosynthetic gene clusters (BGCs). There is keen interest in improving the ability of this platform to overexpress BGCs and, consequently, enable the purification of specialized metabolites. Mutations within gene rpoB for the β-subunit of RNA polymerase are known to increase rifampicin resistance and augment the metabolic capabilities of streptomycetes. Yet, the effects of rpoB mutations on J1074 remained unstudied, and we decided to address this issue. A target collection of strains that we studied carried spontaneous rpoB mutations introduced in the background of the other drug resistance mutations. The antibiotic resistance spectra, growth, and specialized metabolism of the resulting mutants were interrogated using a set of microbiological and analytical approaches. We isolated 14 different rpoB mutants showing various degrees of rifampicin resistance; one of them (S433W) was isolated for the first time in actinomycetes. The rpoB mutations had a major effect on antibiotic production by J1074, as evident from bioassays and LC-MS data. Our data support the idea that rpoB mutations are useful tools to enhance the ability of J1074 to produce specialized metabolites.

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Annotation. Study of features of expression of carbohydrate bits (receptors to lectins) on the surface of cells, in the contests of intracellular granules and on components of extracellular matrix allows to widen the understanding of processes of organs morphogenesis and fabrics and understand the features of reactivity in reply to the action of various factors in the antenatal period of development.Research aim -to set the features of distribution and dynamics of expression of receptors to the wheat germ agglutinin (WGA) in the structures of pancreas in a norm and after the intranatal action of antigens. 126 pancreases of white laboratory rats from a moment birth to ninetieth time of postnatal life were examined in the research work. Rats were retained in a vivarium according to corresponding recommendations. The investigated animals were divided into three groups. The first group is intact rats; the second are control rats, the third are rats, what were undergone intranatal injection of Vaxygrip vaccine. During work with experimental animals followed European convention for defense of vertebrates that are used in experimental and other scientific aims (Strasbourg, 18.03.86). Exposure of carbohydrate bits and pieces of N-acetyl-D-glucosamine in microsections was conducted with application of wheat germ agglutinin (WGA), drawing on the standard set of lectins of SEC "Lectintest" (Lviv). Intensity of deposit of benzidine mark was estimated semi-quantitative. It is set that for experimental animals regardless of way of introduction to the antigen is observed increase of closeness of distribution of carbohydrate bits and pieces of N-acetyl-D-glucosamine in all investigated structures, most expressive in the wall of channels and vessels. Fastening of zymogenic granules of pancreatic exocrine cells acinus with bits and pieces of carbohydrate of N-acetyl-D-glucosamine testifies, that converting of proenzyme into an active form takes place at participation of glycopolymers. As carbohydrate determinants enter in the complement of zymogenic granules of pancreatic exocrine cells, the educed increase in an amount receptor to the lectin of embryos of wheat can influence on composition and properties of enzymes thatis synthesized in acinar cells. Keywords: pancreas, lectin of embryos of wheat, acinar cells, intrafetal introduction to the antigen. ©Вінницький національний медичний університет ім. М.І. Пирогова "Вісник Вінницького національного медичного університету", 2019, Т. 23, №1 ІSSN 1817-7883 eІSSN 2522-9354 96 Dynamics of distribution WGA+ receptors in pancreas in norm and after intranatal action of antigens "Вісник Вінницького національного медичного університету", 2019, Т. 23, №1 ІSSN 1817-7883 eІSSN 2522-9354 ІSSN 1817-7883 "Вісник Вінницького національного медичного університету", eІSSN 2522-9354 2019, Т. 23, №1

In obstetric and gynecological practice for miscarriage treatment the hormone progesterone is widely used.The aim of the study – to learn the correlation of ovarian structures of rats (follicles, connective tissue, blood vessels and corpus luteum) after the administration of progesterone during pregnancy.Materials and Methods. The ovaries of 48 female Wistar rats were investigated on the 45th, 60th and 90th days of life, and they were divided into 3 groups: intact, experimental (the oily solution of progesterone in a dosage 0.33 ml was administered intramuscularly to the female rats from the 15th to the 18th day of pregnancy), and the control group, which was injected with a physiological solution of sodium chloride in an equivalent dosage. The ovaries were fixed in 10 % neutral formalin, serial paraffin cross sections were stained with hematoxylin and eosin.Results and Discussion. From the 45th to the 90th day in the ovaries of experimental animals the connective tissue volume increase and the relative area occupied by the follicles decrease were observed comparing to the control group of animals. The relative area occupied by corpus luteum was significantly greater in the offspring of animals exposed to progesterone during pregnancy than in control animals. As for the blood vessels, there was a decrease in the relative area of vessels in the ovaries of experimental animals during the entire period of observation.Conclusions. In the experimental group of animals we observed the connective tissue and corpus luteum volume increase, but relative area occupied by follicles and blood vessels decreases during the entire observation period.