Hsa_circ_0001658 accelerates the progression of colorectal cancer through miR-590-5p/METTL3 regulatory axis.

BACKGROUND: As reported, multiple circular RNAs (circRNAs) interfere with colorectal cancer (CRC) progression. Here, circRNA_0001658 (circ_0001658) is focused on studying how it works in CRC. AIM: Clarify the expression pattern, biological function, and underlying mechanism of circ_0001658 of CRC tumorigenesis. METHODS: In CRC-related chip data retrieved using the database named Gene Expression Omnibus, different expressions of circRNAs between CRC and normal tissue samples were identified. Quantitative Real-time PCR and Western blot ensured the analysis on circ_0001658, microRNA-590-5P (miR-590-5p), and methyltransferase-like 3 (METTL3) mRNA expressions in tissues and cells. Cell counting kit-8 and flow cytometry were used to detect cell proliferation, apoptosis and migration. The targeting relations between circ_0001658, miR-590-5p, and METTL3 mRNA 3'-untranslated region were under the verification of bioinformatics prediction and dual luciferase-based reporter gene assays. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were employed on the downstream targets of miR-590-5p using the Database for Annotation, Visualization and Integrated Discovery database. RESULTS: Circ_0001658 and METTL3 mRNA was elevated in CRC tissues and cells, whereas miR-590-5p was decreased. Circ_0001658 overexpression promoted the proliferation of HT29 cells, inhibited apoptosis, and accelerated the cell cycle. In SW480 cells, knocking down circ_0001658 had the opposite effect. Circ_0001658 could specifically bind to miR-590-5p and negatively modulate its expressions; METTL3 is a miR-590-5p target that can be positively regulated by circ 0001658. Circ 0001658 was inversely associated with miR-590-5p expression while positively with METTL3 expressions. CONCLUSION: Circ_0001658 regulates the miR-590-5p/METTL 3-axis to increase CRC cell growth and decrease apoptosis.

Production of a Class IIb Bacteriocin with Broad-spectrum Antimicrobial Activity in Lactiplantibacillus plantarum RUB1.

Bacteriocins produced by lactic acid bacteria have potential use as natural food preservatives, which may alleviate current problems associated with the overuse of antibiotics and emerging multi-drug-resistant microbes. In this work, Lactiplantibacillus plantarum RUB1 was found to produce a class IIb bacteriocin with strong antibacterial activity. Except for plnXY encoding putative proteins, L. plantarum RUB1 contains most genes in five operons (plnABCD, plnGHSTUVW, plnMNOP, plnIEF, and plnRLJK) related to bacteriocin synthesis. Adding low (100 and 500 ng/mL) and medium (1 µg/mL) concentrations of PlnA to broth promoted bacteriocin production and upregulated bacteriocin gene plnA, while high concentrations (50 and 200 µg/mL) inhibited expression of these genes. Co-culturing L. plantarum RUB1 with Enterococcus hirae 1003, Enterococcus hirae LWS, Limosilactobacillus fermentum RC4, L. plantarum B6, and even Listeria monocytogenes ATCC 19111 and Staphylococcus aureus ATCC 6538 enhanced bacteriocin activity and expression of bacteriocin-related genes. This study verifies that PlnA can indeed upregulate the expression of bacteriocin genes, and also bacteriocin production can be induced by co-culture with some specific bacteria or their cell-free supernatants. Bacteriocin production by L. plantarum RUB1 is mediated by a quorum sensing mechanism, directly influenced by autoinducing peptide or specific strains. The findings provide new methods and insight into bacteriocin production mechanisms.

Production of a safe cured meat with low residual nitrite using nitrite substitutes.

This work provided a new no-added-nitrite cured meat and an innovative method for substituting nitrite with Lactobacillus fermentum RC4 and Lactobacillus plantarum B6 as starters, beet red and Monascus color as coloring agents, and nisin as antibiotic. Three groups of cured meat were prepared: a no-added-nitrite experimental group (EG), a control group to which only salt was added (CG-S) and a control group to which both salt and nitrite were added (CG-N). After 20 days storage period at 18-20 °C, EG exhibited lower nitrite contents, better sensory characteristics, a greater content of free fatty acids, more volatile compounds, and more plate counts but without pathogenic bacteria compared to EG-S and CG-N. 3-hydroxy-2-butanone, 3-methyl-butanal, 2-methyl-butanal, 2, 4-heptadienal, heptanal, octanal and nonanal were the main flavor substances and palmitic acid, stearic acid, oleic acid, linoleic acid were main FFAs of EG. The no-added nitrite cured meat prepared by this novel method can improve the quality of cured meat and ensure low nitrite content.

Stimulation of insulin secretion by large-dose oral arginine administration in healthy adults.

The effects of large-dose oral arginine administration on the secretion of insulin by islet ß-cells in healthy adults were determined. Eight non-obese healthy volunteers with normal glucose tolerance participated randomly in tests with four stages (with an interval of at least 3 days): the 300 ml purified water stage (PWS), the 75 g glucose stage (GSS), the 30 g arginine stage (ARS) and the 75 g glucose with 30 g arginine stage (GAS). Venous blood samples were collected to detect the concentrations of glucose and insulin at baseline (0) and at 15, 30, 45, 60 and 120 min after drug administration. The glucose and insulin levels were steady in the PWS. The remaining three stages had similarly shaped insulin concentration-time curves, which differed from that of the PWS. The peak concentration of blood insulin and the net incremental area under the curve of blood insulin in the GSS, ARS and GAS were significantly higher compared with those in the PWS (P<0.05). In the ARS, the glucose levels remained stable; however, the net incremental area under the curve for blood insulin in the ARS was much lower compared with that in the GSS or GAS (P<0.05). Large-dose oral arginine administration may slightly stimulate insulin secretion by islet ß-cells in healthy adults with normal glucose tolerance in a manner that is independent of glucose concentration.