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51.
Yu. G. Maksimova D. M. Vasil’ev A. S. Zorina G. V. Ovechkina A. Yu. Maksimov 《Applied Biochemistry and Microbiology》2018,54(2):173-178
The ability of the Alcaligenes faecalis 2 strain to utilize acrylamide and acrylic acid upon cultivation with these compounds as the only sources of carbon and energy has been investigated. Complete utilization of the acrylic acid present in the medium at concentrations below 0.113 g/L was observed by cultivation day 5, at a concentration of 0.225 g/L by day 7, and at a concentration of 0.45 g/L by day 17. Complete utilization of the acrylamide present in the medium at concentrations below 0.4 g/L was observed by day 5, at a concentration of 0.9 g/L by day 7, and at a concentration of 1.8 g/L by day 20. Importantly, bacterial growth did not start before complete transformation of acrylamide into acrylic acid. The rate of acrylamide transformation by growing bacteria and a cell suspension in the stationary growth phase amounted to 12.5 mg/L h at a cell concentration of 610 mg/L and 300 mg/L h, at a concentration of 1500 mg/L. A. faecalis 2 cells immobilized on BVV-22 basalt fibers and Carbopon-B-aktiv at concentrations of 3000 and 800 mg dry cells/L, respectively, transformed acrylamide at a rate of 1200 mg/L h. 相似文献
52.
Yu. G. Maksimova S. M. Nikulin B. M. Osovetskii V. A. Demakov 《Applied Biochemistry and Microbiology》2017,53(5):506-512
A heterogeneous biocatalyst for the biotransformation of nitriles and amides of carboxylic acids in the form of cells of nitrile-hydrolyzing bacteria immobilized on the carrier, was created based on multiwalled carbon nanotubes (MWCNTs). It was shown that bacterial cells form aggregates in contact with powderformed purified or unpurified MWCNTs. The amount of both gram-positive and gram-negative bacteria binding with unpurified MWCNTs was significantly higher than with purified. The nitrile hydratase and amidase activity of bacterial aggregates of purified MWCNTs was preserved to a greater extent as compared to that of unpurified MWCNTs and cells adhered to the surface of the carbonized pyrosealing material with MWCNTs. Both gram-positive Rhodococcus ruber gt1 and gram-negative Alcaligenes faecalis 2 remained viable when cultured in the presence of purified or unpurified MWCNTs. The obtained heterogeneous biocatalyst can be easily separated from the medium by filtration and can be used repeatedly. 相似文献
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Marina Yurievna Maksimova Alexander Vladimirovich Ivanov Edward Danielevich Virus Ksenya Alexandrovna Nikiforova Fatima Ramazanovna Ochtova Ekaterina Taymurazovna Suanova Maria Petrovna Kruglova Mikhail Aleksanrovich Piradov Aslan Amirkhanovich Kubatiev 《Redox report : communications in free radical research》2021,26(1):117
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Maksimova I. V. Matorin D. N. Plekhanov S. E. Vladimirova M. G. Volgin S. L. Maslova I. P. 《Russian Journal of Plant Physiology》2000,47(6):779-785
The effects of light and temperature conditions on the maintenance of some red microalgae (order Porphyridiales) in collections were studied. Periodical subculturing on solid and liquid media was used for maintenance. Halophilic species P. aeruginosa, P. cruentum, and P. sordidum were lost in 2.5 months if kept in darkness. The viability of algae in the dim light slightly declined in 4–5 months and was species-dependent. The results were compared with earlier obtained data on mesophilic Chlorococcales. For the green algae, darkness proved to be the optimal condition, while their viability markedly decreased at light. It was suggested that this discrepancy was caused by the presence of phycobiliproteins in the cells of red algae. Dim light conditions are optimal for the synthesis of phycobiliproteins, which are rapidly destroyed in darkness, thus leading to cell death. 相似文献
57.
Interest in the use of low-copy nuclear genes for phylogenetic analyses of
plants has grown rapidly, because highly repetitive genes such as those
commonly used are limited in number. Furthermore, because low- copy genes
are subject to different evolutionary processes than are plastid genes or
highly repetitive nuclear markers, they provide a valuable source of
independent phylogenetic evidence. The gene for granule-bound starch
synthase (GBSSI or waxy) exists in a single copy in nearly all plants
examined so far. Our study of GBSSI had three parts: (1) Amino acid
sequences were compared across a broad taxonomic range, including grasses,
four dicotyledons, and the microbial homologs of GBSSI. Inferred structural
information was used to aid in the alignment of these very divergent
sequences. The informed alignments highlight amino acids that are conserved
across all sequences, and demonstrate that structural motifs can be highly
conserved in spite of marked divergence in amino acid sequence. (2)
Maximum-likelihood (ML) analyses were used to examine exon sequence
evolution throughout grasses. Differences in probabilities among
substitution types and marked among-site rate variation contributed to the
observed pattern of variation. Of the parameters examined in our set of
likelihood models, the inclusion of among-site rate variation following a
gamma distribution caused the greatest improvement in likelihood score. (3)
We performed cladistic parsimony analyses of GBSSI sequences throughout
grasses, within tribes, and within genera to examine the phylogenetic
utility of the gene. Introns provide useful information among very closely
related species, but quickly become difficult to align among more divergent
taxa. Exons are variable enough to provide extensive resolution within the
family, but with low bootstrap support. The combined results of amino acid
sequence comparisons, maximum-likelihood analyses, and phylogenetic studies
underscore factors that might affect phylogenetic reconstruction. In this
case, accommodation of the variable rate of evolution among sites might be
the first step in maximizing the phylogenetic utility of GBSSI.
相似文献
58.
Glushakova A. M. Lysak L. V. Kachalkin A. V. Ivanova A. E. Umarova A. B. Abramyan I. A. Ezhelev Z. S. Maksimova I. A. 《Microbiology》2021,90(2):176-186
Microbiology - In a model experiment, the transformation of microbial complexes of cultivated saprotrophic bacteria and yeasts during freezing-thawing was studied in various natural substrates that... 相似文献
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Regulation of tryptophan biosynthesis of facultative methylotrophic Pseudomonas sp. M was studied. Repression of the trpE, trpD and trpC genes by tryptophan was demonstrated. It was also shown that the trpE and trpDC genes are derepressed noncoordinately. No regulation of the trpF gene product could be demonstrated, indicating that its synthesis is constitutive. The trpA and trpB genes are inducible by indol-3-glycerophosphate. Anthranilate synthase and tryptophan synthase were sensitive to the feedback inhibition. The tryptophan concentrations giving 50% inhibition were estimated to be 9 microM and 1 microM, respectively. Experimental evidence for activation of the N-5-phosphoribosyl anthranilate isomerase and for inhibition of the indol-3-glycerophosphate synthase by some tryptophan intermediates was obtained. 相似文献