Microbial Cold Shock Proteins: Overview of their Function and Mechanism of Action.

The organism responds to a decrease in temperature by producing a series of cold shock proteins (CSPs). These proteins play a critical role in growing and functioning characteristics at low temperatures. CSPs have been discovered in a wide range of organisms and have shown enormous diversity; their mechanisms of action are also complicated. Transcription and translation in microorganisms typically occur via a single linear chain, but upon exposure to low temperatures, RNA forms a complex secondary structure that prevents ribosomes from binding to it, thus slowing down translation. CSPs bind to mRNA as RNA molecular chaperones to keep the mRNA secondary structure in a single-stranded linear conformation, allowing successful translation at low temperatures.

Complete genome sequencing of Bacillus sp. TK-2, analysis of its cold evolution adaptability.

To date, a large number of Bacillus species from different sources have been identified. However, there are few investigations on genome information and evolutionary insights of Bacillus species from cold environments. Bacillus sp. TK-2, isolated from the soil of Changbai Mountain, is a gram-positive bacterium with cold adaptation characteristics. In this study, we present the annotated complete genome sequence of Bacillus sp. TK-2. The genome comprised 5,286,177 bp with a GC content of 35.88%, 5293 protein-encoding genes, 32 rRNA, and 77 tRNA. Numerous genes related to cold adaptation were detected in the genome of Bacillus sp. TK-2, mainly involving in energy supply, regulation of cell membrane fluidity, antioxidant, and molecular chaperones. In addition, the strain TK-2 classified in the Bacillus groups was distributed on a terminal branch with Bacillus cereus A1 by Blastn and phylogenetic analysis in NCBI database. Complete genome sequences of the strain TK-2 and Bacillus cereus A1 were compared by the online tool "Average Nucleotide Identity", showing that the average nucleotide identity of these two strains was 98.26%. In parallel, A comparative analysis of the genomes of both Bacillus sp. TK-2 and Bacillus cereus A1 was conducted. Through the analysis of core and specific genes with cd-hit, it was found that the two strains had 5691 pan gene, 4524 core gene, and 1167 specific gene clusters. Among the 624 specific gene clusters of Bacillus sp. TK-2, some cold tolerance genes were detected, which implied the unique adaptability of Bacillus sp. TK-2 in long-term low temperature environments. Importantly, enzyme-encoding genes related to the degradation of polysaccharides such as cellulose and hemicellulose were detected in the 477 CAZyme genes of this genome. This work on sequencing and bioinformatics analysis of the complete sequence of Bacillus sp. TK-2 promote the application and in-depth research of low-temperature biotechnology.

Anti-Diabetic Effect of Portulaca oleracea L. Polysaccharideandits Mechanism in Diabetic Rats.

Diabetes mellitus (DM) is a metabolic syndrome caused by multiple genetic and environmental factors. Traditional Chinese medicine preparations have shown a comprehensive and function-regulating characteristic. Purslane (Portulaca oleracea L.) is an annual succulent herb. Currently, there have been some related reports on the treatment of diabetes with purslane. The current study was designed to separate and purify the polysaccharide, a systematic study of its physical and chemical properties, antioxidant activity, and anti-diabetic mechanism, in order to provide a theoretical basis for the development of drugs of purslane. A crude water soluble polysaccharide extracted from purslane was named CPOP (crude Portulaca oleracea L. polysaccharide). Effects of CPOP on bodyweight, glucose tolerance test (GTT), fasting blood glucose (FBG), fasting serum insulin (FINS), insulin sensitivity index (ISI), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), methane dicarboxylic aldehyde (MDA), and superoxygen dehydrogenises (SOD) were investigated. The results indicate that the oral administration of CPOP could significantly increase the body weight and significantly improve the glucose tolerance in diabetic rats. Meanwhile, CPOP could significantly reduce the FBG level, and elevate the FINS level and ISI value in diabetic rats. In addition, CPOP could significantly reduce TNF-α and IL-6 levels in diabetic rats; CPOP could also reduce MDA and SOD activities in the liver tissue of diabetic rats. These results suggest that the anti-diabetic effect of CPOP may be associated with its antioxidant and anti-inflammatory effects.