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Документ Effect of environmental factors on the synthesis and properties of Acinetobacter sp. exopolysaccharides(1998) Pirog, Tatiana; Grinberg, Tamara; Malashenko, YuriEffects of external factors on the synthesis and physicochemical properties of Acinetobacter sp. exopolysaccharides (EPSs), which determine the biological functions of this microorganism, were studied. The cultivation temperature, medium pH, and oxygen concentration in the medium (p02) affected the viscosity of EPS solutions in the presence of monovalent cations, in the H+-form, and in a Cu2+-glycine system. All the EPSs studied were precipitated with heavy metal ions (Cr3+, Cu2+, Pb2+, Cd2+, etc.). No changes in the EPS yield were observed under unfavorable environmental conditions. At high pO2 values (up to 80% of saturation), the maximum specific rates of bacterial growth and EPS synthesis increased. It was suggested that Acinetobacter sp. EPSs perform different biological functions under optimal and nonoptimal conditions.Документ Ethapolan: a new microbial exopolysaccharide for oil industry(1995) Grinberg, Tamara; Pirog, Tatiana; Malashenko, Yuri; Vlasov, Sergei A.Ethapolan, a new high-viscous exopolysaccharide, was obtained in the course of microbial synthesis. Its chemical content and some characteristics of its solutions are explored in the present study. By its structure ethapolan may be considered a polysaccharide of xanthan type. More definitely, as compared to xanthan, the emulsifying efficiency and hydrophobic nature of ethapolan may be attributed to the presence of the fatty acids residues and to 6-desoxysaccharide—rhamnose residues. It was found that a few factors impact the increasing viscosity of ethapolan solutions: first, the presence of the cations; second, low shearing rates; and, finally, low pH values. Ethapolan is resistant to heating. On this basis, it may be concluded that ethapolan appears to be a universal and quite competitive microbial exopolysaccharide for the oil industry.Документ Isolation and characterization of Acinetobacter sp. mutants defective in exopolysaccharide biosynthesis(2000) Pirog, Tatiana; Stolyar, S.; Malashenko, YuriNitrosoguanidine-induced mutants ofAcinetobacter sp. defective in exopolysaccharide biosynthesis did not differ from the parent strain in distinguishing physiological and biochemical properties, such as requirements for growth factors, utilization of mono- and disaccharides, and resistance to antibiotics. The genetic relation of parent and mutant strains was shown by 16S rRNA PCR analysis. The comparative study of parent and mutant strains with respect to resistance to unfavorable environmental factors confirmed our hypothesis that Acinetobacter sp. exopolysaccharides perform protective functions. Hybridization experiments revealed the conjugal transfer of plasmid R68.45 from Pseudomonas putida BS228 (R68.45) to mutant but not to the parent Acinetobacter sp. strains. The role of the Acinetobacter sp. exopolysaccharides in providing the genetic stability of this bacterium is discussed. Методом нітрозогуанідінового мутагенезу отримані мутантні штами Acinetobacter sp., Що не утворюють Екзополісахариди (ЄПС). Вихідний і мутантні штами не відрізняються між собою по ряду характерних для цих бактерій фізіолого-біохімічних ознак (потреба в ростових факторах, асиміляція моно-і дисахаридів, стійкість до антибіотиків). Ідентичність вихідного і мутантних штамів встановлена також на основі аналізу їх 16S рРНК. Результати вивчення стійкості клітин вихідного та мутантних штамів до несприятливих факторів підтвердили захисні функції ЕПС Acinetobacter sp. по відношенню до клітин продуцента. При схрещуванні Acinetobacter sp. з Pseudomonas putida BS228 (R68.45) здійснено кон'югатівний перенесення плазміди R68.45 в клітини мутантних (але не початкового) штамів. Обговорюється роль ЕПС Acinetobacter sp. як одного з факторів, що забезпечують генетичну стабільність штаму-продуцента.Документ Search for methanotrophic producers of exopolysaccharides(2001) Malashenko, Yuri; Pirog, Tatiana; Romanovska, V.; Malashenko, Yuri; Sokolov, I.; Grinberg, TamaraBacteria that produce exopolysaccharides (EPS) and use methane as the only source of carbon were selected by studying a collection of methanotroph strains: Methylococcus capsulatus E 494, 874, and 3009; M. thermophilus 111p, 112p, and 119p; Methylobacter ucrainicus 159 and 161; M. luteus 57v and 12b; Methylobacter sp. 100; Methylomonas rubra 15 sh and SK-32; Methylosinus trichosporium OV3b, OV5b, and 4e; M. sporium 5,12, A20d, and 90v; and Methylocystis parvus OVVP. Mesophilic methanotroph strains with the ribulose monophosphate way of C1-compound assimilation synthesized EPS more actively than bacteria operating the serine cycle. The dynamics of EPS synthesis by methanotrophs during chemostat cultivation was studied.