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Sourik Dey Marc Blanch-Asensio Sanjana Balaji Kuttae Shrikrishnan Sankaran 《Microbial biotechnology》2023,16(6):1264-1276
Lactobacilli are ubiquitous in nature, often beneficially associated with animals as commensals and probiotics, and are extensively used in food fermentation. Due to this close-knit association, there is considerable interest to engineer them for healthcare applications in both humans and animals, for which high-performance and versatile genetic parts are greatly desired. For the first time, we describe two genetic modules in Lactiplantibacillus plantarum that achieve high-level gene expression using plasmids that can be retained without antibiotics, bacteriocins or genomic manipulations. These include (i) a promoter, PtlpA, from a phylogenetically distant bacterium, Salmonella typhimurium, which drives up to 5-fold higher level of gene expression compared to previously reported promoters and (ii) multiple toxin-antitoxin systems as a self-contained and easy-to-implement plasmid retention strategy that facilitates the engineering of tuneable transient genetically modified organisms. These modules and the fundamental factors underlying their functionality that are described in this work will greatly contribute to expanding the genetic programmability of lactobacilli for healthcare applications. 相似文献
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K. Sankaran Unni 《Hydrobiologia》1971,37(1):139-155
Summary The distribution of aquatic plants in Doodhadhari lake, Raipur, M.P., India was studied by establishing eight stations. Permanent belt transects were run from all these eight stations every month for a year to assess the seasonal change in vegetational composition. Each transect was taken from the shore to the maximum depth. A contour survey was made and the total area during different seasons were determined. The fluctuation of water level was marked almost every fortnight for a year. The percentage frequency and percentage cover of different species were found to exhibit significant changes during different seasons. Except a few submerged aquatic plant species which are perennial all other species appear and disappear as the seasons progress. The perennial species which are not much affected by the seasonal change are heavily eaten by cattles. The pattern of succession has been outlined after evaluating the changes. 相似文献
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