The mechanisms of L-alanine overproduction by Brevibacterium flavum producer strains were studied. It was shown that beta-CI-L-alanine is an inhibitor of some key enzymes involved in the synthesis of L-alanine, including alanine transaminase and valine-pyruvate transaminase. Two highly active B. flavum GL1 and GL1 8 producer strains, which are resistant to the inhibitory effect of beta-Cl-L-alanine, were obtained using a parental B. flavum AA5 producer strain, characterized by a reduced activity of alanine racemase (>or=98%). It was demonstrated that the increased L-alanine synthesis efficiency observed in the producer strains developed in this work is associated with the absence of inhibition of alanine transaminase by the end product of the biosynthesis reaction, as well as with the effect of derepression of both alanine transaminase and valine-pyruvate transaminase synthesis by the studied compound.
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http://dx.doi.org/10.7868/s0555109913020098 | DOI Listing |
Adv Biotechnol (Singap)
August 2024
State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Stress Biology and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China.
Extreme environments such as hyperarid, hypersaline, hyperthermal environments, and the deep sea harbor diverse microbial communities, which are specially adapted to extreme conditions and are known as extremophiles. These extremophilic organisms have developed unique survival strategies, making them ideal models for studying microbial diversity, evolution, and adaptation to adversity. They also play critical roles in biogeochemical cycles.
View Article and Find Full Text PDFAdv Biotechnol (Singap)
March 2024
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China.
Engineering microbial cell factories have achieved much progress in producing fuels, natural products and bulk chemicals. However, in industrial fermentation, microbial cells often face various predictable and stochastic disturbances resulting from intermediate metabolites or end product toxicity, metabolic burden and harsh environment. These perturbances can potentially decrease productivity and titer.
View Article and Find Full Text PDFISME J
January 2025
Department of Plant Pathology, University of Georgia, Athens, GA, United States.
Pantoea agglomerans is one of four Pantoea species reported in the USA to cause bacterial rot of onion bulbs. However, not all P. agglomerans strains are pathogenic to onion.
View Article and Find Full Text PDFJ Virol
January 2025
Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.
Unlabelled: Coronaviruses have large, positive-sense single-stranded RNA genomes that challenge conventional strategies for mutagenesis. Yeast genetics has been used to manipulate large viral genomes, including those of herpesviruses and coronaviruses. This method, known as transformation-associated recombination (TAR), involves assembling complete viral genomes from dsDNA copies of viral genome fragments via homologous recombination in .
View Article and Find Full Text PDFmBio
January 2025
Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA.
Unlabelled: Mutations affecting flagellin (FliC) have been shown to be hypervirulent in animal models and display increased toxin production and alterations in central metabolism. The regulation of flagellin levels in bacteria is governed by a tripartite regulatory network involving , , and , which creates a feedback system to regulate flagella production. Through genomic analysis of clade 5 strains (non-motile), we identified they have jettisoned many of the genes required for flagellum biosynthesis yet retain the major flagellin gene and regulatory gene .
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