Wei Song

Antidiabetic (type 2) effects of Lactobacillus G15 and Q14 in rats through regulation of intestinal permeability and microbiota

The antidiabetic effects of Lactobacillus. paracasei subsp. paracasei G15 and Lactobacillus. casei Q14 in high fat diet and streptozotocin-induced type 2 diabetic (T2D) rats were evaluated in this study. The strains were separated from Chinese traditional fermented dairy food. Administration of G15 and Q14 for 6 weeks significantly improved the glucose tolerance and reduced the HbA1c levels in T2D rats. The probiotic treatment reduced the intestinal mucosal permeability and improved the epithelial barrier function through modification of the gut microbiota, which in turn lowered circulating LPS and inflammation cytokines, including IL-1β and IL-8, and eventually alleviated the inflammatory status and islet β-cell dysfunction. Combination of Q14 and metformin reversed the thymic atrophy and both G15 and Q14 lowered the circulating IL-6 level, indicating the immune-modulating potential of the strains. Lactobacillus. paracasei subsp. paracasei G15 and Lactobacillus. casei Q14 provide an insight into the biotherapy application of traditional fermented foods and their functional ingredients in the treatment of diabetes.

Injury Mechanisms of Lactic Acid Bacteria Starter Cultures During Spray Drying: A Review

Lactic acid bacteria (LAB) starter cultures can be processed by many drying techniques, among which spray drying has great potential. However, injuries of LAB during spray drying lead to a low survival rate. The microbial injuries of LAB during spray drying are specifically induced by dehydration inactivation, thermal inactivation, and balance between the two. To reduce the drying temperature, new drying techniques based on spray drying were tried; that is, low-temperature vacuum–spray drying and spray–freeze drying.

Sulforaphane attenuates homocysteine-induced endoplasmic reticulum stress through Nrf-2-driven enzymes in immortalized human hepatocytes.

UNLABELLEDnIn the present study, we investigated the potential efficacy of cruciferous vegetable-derived sulforaphane (SFN) in improving homocysteine (HCY)-stressed cells. After human hepatocyte line HHL-5 was preincubated with SFN and subsequently with 10 mmol/L HCY, SFN improved the pathologic changes which are caused by HCY, including cell morphological abnormality, endoplasmic reticulum (ER) swelling, excessive generation of reactive oxygen species (ROS), the increased malondialdehyde (MDA) levels, as well as the increased activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Phase II enzymes, thioredoxin reductase-1 (TrxR-1) andnnnNAD(P)Hnquinone oxidoreductase 1 (NQO1), were involved in the protective effect of SFN against injury by HCY. The ER stress-specific proteins, such as glucose-regulated protein-78 (GRP78) and protein kinase RNA (PKR)-like ER kinase (PERK), were strikingly abolished by SFN. Furthermore, Nrf-2 translocation was enhanced by SFN, which lead to the induction of TrxR-1and NQO1.

Thrombin inhibitory peptides derived from Mytilus edulis proteins: identification, molecular docking and in silico prediction of toxicity

Optimization of the thrombin inhibitory activities of different enzymatic hydrolysates was conducted, and then an optimal hydrolysis condition by trypsin (5000xa0u/g) was determined as follows, digested at 45xa0°C and pH 8.5 for 2xa0h with a protein concentration of 25xa0mg/mL. Thrombin inhibitory activity was proved to be 76.92xa0±xa04.66% under this condition. A total of 39 peptides were identified in the hydrolysate by UPLC-Q-TOF–MS/MS, and all the peptides were predicted to be nontoxic by in silico predictive approaches. Twenty-six peptides were predicted to be anticoagulant peptides by molecular docking method, and the peptide 26 (Lys-Asn-Ala-Glu-Asn-Glu-Leu-Gly-Glu-Val-Thr-Val-Arg) was predicted to be a better anticoagulant peptide through both structure–activity relationship and affinity activity to thrombin. The interactional positions between peptide and thrombin were also involved in the interaction site on the S1 pocket of thrombin and strongly promoted its thrombin inhibitory activity. The firmly non-bonded interactions made the bound of peptide and thrombin firmly. Eventually, the chemical identification and activity verification of synthetic peptide 26 were conducted, and the thrombin inhibitory activity was 89.96xa0±xa05.30% at the concentration of 9xa0mg/mL. This study optimized an enzymatic hydrolysis and a virtual screening method for predicting and verifying the anticoagulant peptide from Mytilus edulis, respectively, which provided a good theoretical basis and application method for the research and development of the anticoagulant peptides, especially from the seafood products.

The antioxidative effects of three lactobacilli on high-fat diet induced obese mice

In this paper, three Lactobacillus strains (L. coryniformis subsp. torquens T3, L. paracasei subsp. paracasei M5 and L. paracasei subsp. paracasei X12) isolated in our laboratory were investigated for antioxidant activity in vitro and in vivo. Hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activities and reducing power were examined in vitro. Three Lactobacillus strains were administered to high-fat diet induced obese mice. The results indicated that T3 and M5 showed the highest hydroxyl radical and DPPH scavenging activities at a dose of 109 CFU mL−1, with inhibition rates of 40.33, 41.11% and 40.76, 44.31%, respectively. The reducing activities of these two strains were also significantly higher than those of X12. Compared with the high-fat diet group, M5 and T3 have effectively controlled body weight and hepatomegaly and significantly decreased blood triglyceride and total cholesterol levels (p < 0.05). Besides, M5 and T3 obviously improved the antioxidative indexes including MDA levels, T-SOD, GSH-Px, CAT and T-AOC activities. Overall, M5 and T3 have a strong antioxidant activity in vitro and can improve oxidative damage and control body weight in mice, suggesting that they may be potential anti-obesity and antioxidant probiotics.

A novel enterocin T1 with anti-Pseudomonas activity produced by Enterococcus faecium T1 from Chinese Tibet cheese

An enterocin-producing Enterococcus faecium T1 was isolated from Chinese Tibet cheese. The enterocin was purified by SP-Sepharose and reversed phase HPLC. It was identified as unique from other reported bacteriocins based on molecular weight (4629xa0Da) and amino acid compositions; therefore it was subsequently named enterocin T1. Enterocin T1 was stable at 80–100xa0°C and over a wide pH range, pH 3.0–10.0. Protease sensitivity was observed to trypsin, pepsin, papain, proteinase K, and pronase E. Importantly, enterocin T1 was observed to inhibit the growth of numerous Gram-negative and Gram-positive bacteria including Pseudomonas putida, Pseudomonas aeruginosa, Pseudomonas fluorescens, Escherichia coli, Salmonella typhimurium, Shigella flexneri, Shigella sonnei, Staphylococcus aureus, Listeria monocytogenes. Take together, these results suggest that enterocin T1 is a novel bacteriocin with the potential to be used as a bio-preservative to control Pseudomonas spp. in food.

Analysis of volatile compounds and nutritional properties of enzymatic hydrolysate of protein from cod bone

Hydrolysis of the proteins from cod bone was performed using flavourzyme and trypsin. The nutritional properties of hydrolysates by flavourzyme (HF) and trypsin (HT) were investigated. By comparison, HF exhibits a better degree of hydrolysates (DH) and nitrogen recovery (NR) than HT. The protein content of extract is 97.39% and had a good nutritional value due to the high protein digestibility-corrected amino acid score (PDCAAS) of 0.95 for adults. The content of total amino acids is 942.55u202fmg/g. The free amino acids content of hydrolysates derived from flavourzyme is 136.82u202fmg/g after hydrolyzing 3u202fh, while 17.12u202fmg/g of such hydrolysates was obtained by using trypsin. The main flavor compounds are alcohols, aldehydes, ketones, acids and alkanes. The molecular weight of predominant peptides ranged from 1000 to 3000u202fDa in both enzymatic hydrolysates. This study provided a theoretical basis to the preparation of nutritional components with attracting flavor in functional food industry.