Coordinated Regulation of Polyhydroxybutyrate Biosynthesis by Various Phasins under Different Conditions
Polyhydroxybutyrate (PHB) granules are a store of carbon and energy in prokaryotes, and they are involved in stress adaptation. However, the roles of various granule-associated proteins of PHB remain largely unexplored. Studies by Sun et al. (e00717-19) demonstrated that Sinorhizobium fredii strain NGR234, a facultative microsymbiont of diverse legumes, can use both conserved and accessory granule-associated proteins (phasins) to coordinately regulate the size and number of PHB granules under free-living and symbiotic conditions. This work suggests a condition-dependent role of different phasins in regulating PHB biosynthesis.
Surface Molecules Mediating Adhesion of Lactobacillus gasseri to Vaginal Epithelial Cells
The molecular mechanisms for health-promoting effects of lactobacilli are not fully understood. Zeng et al. (e00800-19) functionally identified three cell surface factors of a probiotic Lactobacillus gasseri strain potentially involved in its adhesion to vaginal epithelial cells, including exopolysaccharides and two sortase-dependent proteins. They demonstrated that exopolysaccharides and a putative novel adhesin (LVEA) mediate specific binding to vaginal epithelial cells. The results provide important information on the molecular mechanisms of vaginal Lactobacillus species adhesion and mucosal tissue tropism and could enable screening for better probiotic candidates in the future.
Fecal Microbiotas of Indonesian and New Zealand Children Are Different
Analysis by Lawley and colleagues (e01105-19) of DNA sequences generated from fecal microbiotas of infants during the first year of life showed marked differences in taxonomic compositions, complexity, and development. The abundances of Bifidobacterium longum subspecies infantis and longum differed greatly between the two cohorts. The differences in microbiota development were most likely related to the contrasting prevalence and duration of breastfeeding of infants in the two countries. The results of the study help develop concepts of the microbial ecology of the human gut. These concepts may be useful in understanding the long-term effects of microbiological events in early life on health and well-being.
Schizochytrium, a Promising Natural Astaxanthin-Producing Microorganism
Due to its powerful antioxidant characteristics, astaxanthin has begun to draw substantial scientific and commercial attention. Recently, Du et al. (e01243-19) studied a new astaxanthin-producing Schizochytrium strain by using transcriptome analysis. These authors investigated the regulation of signaling and metabolic pathways (mainly relative gene expression) in Schizochytrium grown in the presence of various concentrations of methanol. This study contributes to the understanding of the underlying molecular mechanisms and may aid in the future optimization of Schizochytrium for astaxanthin biosynthesis.
Genetic Transformation of a Phototrophic Firmicute
In 1983, the first member of the Heliobacteriaceae, the only family of photosynthetic bacteria in the phylum Firmicutes, was discovered. Since then, numerous studies have been performed to elucidate the details of their uniquely simple photosynthetic apparatus, their central carbon metabolism, and their ability to reduce heavy metals such as mercury. Baker et al. (e01287-19) succeeded in genetically transforming Heliobacterium modesticaldum by adapting techniques used with nonphotosynthetic members of the phylum. This opens the door for further genetic studies of heliobacteria using H. modesticaldum as the new model organism for this family.
- Copyright © 2019 American Society for Microbiology.
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- Coordinated Regulation of Polyhydroxybutyrate Biosynthesis by Various Phasins under Different Conditions
- Surface Molecules Mediating Adhesion of Lactobacillus gasseri to Vaginal Epithelial Cells
- Fecal Microbiotas of Indonesian and New Zealand Children Are Different
- Schizochytrium, a Promising Natural Astaxanthin-Producing Microorganism
- Genetic Transformation of a Phototrophic Firmicute
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