The extracellular vesicles from gram-positive bacteria: a review / 生物工程学报

Extracellular vesicles (EVs), also known as membrane vesicles, are vesicular bodies secreted by eukaryotic cells and bacteria. EVs can carry proteins, DNA, RNA, and various metabolites for the exchange and transmission of substances between cells. They play contents-dependent physiological functions, such as delivering nutrients, participating in immune response, and treating cancers. Currently, most studies focus on the exploration of vesicles secreted by eukaryotic cells and gram-negative bacteria, while few studies focus on gram-positive bacteria. This review summarized the production, content composition, physiological function, and engineering of EVs secreted by gram-positive bacteria, and prospected future perspectives in this area.

MALAT1 upregulates SMYD3 by competition with miR-124 and promotes proliferation and migration of breast cancer cells / 中国药科大学学报

@#To investigate whether lncRNA MALAT1 affects the migration and proliferation of breast cancer cells through the regulation with histone methyltransferase SMYD3, the endogenous MALAT1 in the MCF-7 and MDA-MB-231 breast cancer cells were knocked down by siRNA, and then the migration and proliferation of cells were detected by wound healing migration and MTT assay. The effects of si-MALAT1 on the mRNA and protein levels of miRNA-124, SMYD3 and its downstream genes were detected by Real time PCR and Western blot. The results showed that siRNA-targeted knockdown of MALAT1 reduced the migration and proliferation of breast cancer cells, and inhibited the transcriptional expression of SMYD3 and its downstream genes, including N-cadherin, MYL9, MMP9 and CYR61, and up-regulated miR-124. Overexpression of miR-124 reduced the expression of SMYD3 in breast cancer cells, and knockdown of MALAT1 attenuated the promotion of SMYD3 protein expression by miR-124 inhibitors. In addition, SMYD3 overexpression activated MALAT1 transcription, whereas siRNA interference with SMYD3 downregulated MALAT1. These results indicate that LncRNA MALAT1 acted as a competing endogenous RNA(ceRNA)of miR-124 to regulate expression of SMYD3 in breast cancer cells, and SMYD3 can activate the transcription of MALAT1, which will affect the proliferation and migration of breast cancer cells.

The effect of moderate static magnetic fields on secretion of pro-inflammatory factors in THP-1 cells / 天津医药

Objective To investigate the effect of moderate static magnetic fields (SMF) on secretion of inflammato?ry factors tumor necrosis factor-α(TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8) in human monocytic leukemic cell line THP-1. Methods THP-1 cells at logarithmic phase were divided into control group and magnetic treatment group. CCK-8 method was used to detect cell proliferation after THP-1 cells were exposed to 60 mT, 200 mT and 400 mT static magnetic fields at 18, 24 and 48 h. Then THP-1 cells were divided into control group, magnetic treatment group, LPS activation group and LPS+SMF treatment group. When magnetic treatment group and LPS+SMF treatment group were ex?posed to SMF at 18, 24 and 48 h, the levels of the cytokines TNF-α, IL-6 and IL-8 were determined by ELISA. Results (1) 60 mT, 200 mT and 400 mT SMF had no significant effects on cell proliferation in THP-1 cells (P>0.05). (2)THP-1 cells secreted more TNF-αand IL-6 in 24 h than 18 h in every group, while IL-8 didn′t change. Compared with 24 h, the secre?tion of TNF-αdecreased and IL-6 didn′t change, while IL-8 increased in 48 h. At three sampled time THP-1 cells of LPS activation group secreted more TNF-α, IL-6, IL-8 than those of control group and magnetic treatment group. After magnetic treatment THP-1 cells of LPS+SMF treatment group secreted less TNF-α, IL-6, IL-8 than those of LPS activation group (P<0.05). Conclusion Static magnetic field may have some inhibitory effects on release of TNF-α, IL-6, IL-8 from THP-1 cells, which can provide basic data for the treatment of rheumatoid arthritis.

Production of sugar syrup containing rare sugar using dual-enzyme coupled reaction system / 生物工程学报

Enzymatic conversion is very important to produce functional rare sugars, but the conversion rate of single enzymes is generally low. To increase the conversion rate, a dual-enzyme coupled reaction system was developed. Dual-enzyme coupled reaction system was constructed using D-psicose-3-epimerase (DPE) and L-rhamnose isomerase (L-RhI), and used to convert D-fructose to D-psicose and D-allose. The ratio of DPE and L-RhI was 1:10 (W/W), and the concentration of DPE was 0.05 mg/mL. The optimum temperature was 60 degrees C and pH was 9.0. When the concentration of D-fructose was 2%, the reaction reached its equilibrium after 10 h, and the yield of D-psicose and D-allose was 5.12 and 2.04 g/L, respectively. Using the dual-enzymes coupled system developed in the current study, we could obtain sugar syrup containing functional rare sugar from fructose-rich raw material, such as high fructose corn syrup.

Screening of food-grade microorganisms for biotransformation of D-tagatose and cloning and expression of L-arabinose isomerase / 生物工程学报

L-Arabinose isomerase (L-AI) is an intracellular enzyme that catalyzes the reversible isomerization of D-galactose and D-tagatose. Given the widespread use of D-tagatose in the food industry, food-grade microorganisms and the derivation of L-AI for the production of D-tagatose is gaining increased attention. In the current study, food-grade strains from different foods that can convert D-galactose to D-tagatose were screened. According to physiological, biochemical, and 16S rDNA gene analyses, the selected strain was found to share 99% identity with Pediococcus pentosaceus, and was named as Pediococcus pentosaceus PC-5. The araA gene encoding L-AI from Pediococcus pentosaceus PC-5 was cloned and overexpressed in E. coli BL21. The yield of D-tagatose using D-galactose as the substrate catalyzed by the crude enzyme in the presence of Mn2+ was found to be 33% at 40 degrees C.