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Chlorpyrifos is a commonly-used pesticide which was reported to interfere with hormone signaling and metabolism, however, little is known about its effect on gut microbiota. In this study, adult male rats fed a normal (NF) or high fat (HF) diet were exposed to 0.3 or 3.0 mg chlorpyrifos/kg bodyweight/day or vehicle alone for 9 weeks. Effects on bodyweight, serum levels of glucose, lipid, cytokines, and gut microbiome community structure were measured. The effects of chlorpyrifos on metabolism were dose- and diet-dependent, with NF-fed rats administered the low dose showing the largest metabolic changes. NF-fed rats exposed to chlorpyrifos exhibited a pro-obesity phenotype compared with their controls, whereas there was no difference in pro-obesity phenotype between HF-fed groups. Chlorpyrifos exposure significantly reduced serum insulin, C-peptide, and amylin concentrations in NF- and HF-fed rats, leaving serum glucose and lipid profiles unaffected. Chlorpyrifos exposure also significantly altered gut microbiota composition, including the abundance of opportunistic pathogens, short chain fatty acid-producing bacteria and other bacteria previously associated with obese and diabetic phenotypes. The abundance of bacteria associated with neurotoxicity and islet injury was also significantly increased by chlorpyrifos. Our results suggest risk assessments for chlorpyrifos exposure should consider other effects in addition to neurotoxicity.

In order to colonize the human gastrointestinal tract and exert their beneficial effects, bifidobacteria must effectively cope with the toxic bile salts in the intestine, but the molecular mechanism underlying bile tolerance is poorly understood. In this study, heterologous expression of a MarR family transcriptional regulator BmrR significantly reduced ox-bile resistance ofLactococcus lactisNZ9000, suggesting that it might play a role in bile stress response.In silicoanalysis combined with RT-PCR assay demonstrated thatbmrRwas co-transcribed withbmrAandbmrB,which encoded multidrug resistance (MDR) ABC transporters. Promoter prediction and EMSA assay revealed that BmrR could autoregulate thebmrRABoperon by binding tobmrbox (ATTGTTG-6nt-CAACAAT) in the promoter region. Moreover, heterologous expression ofbmrAandbmrBinL. lactisshowed 20.77-fold higher tolerance to 0.10% ox-bile compared to wild type strain. In addition, ox-bile could disrupt the DNA binding activity of BmrR as a ligand. Taken together, our findings indicate thatbmrRABoperon is autoregulated by transcriptional regulator BmrR and ox-bile serves as an inducer to activate the bile efflux transporter BmrAB in response to bile stress inB. longumBBMN68.ImportanceBifidobacteria are natural inhabitants of the human intestinal tract. Some bifidobacterial strains are used as probiotics in fermented dairy production because of their health-promoting effects. Following consumption, bifidobacteria finally colonize the lower intestinal tract where the concentration of bile salts remains nearly 0.05% to 2.0%. Bile salts as detergent-like antimicrobial compounds can cause disruption of the cellular membrane, protein misfolding and DNA damage. Therefore, tolerance to physiological bile stress is indeed essential for bifidobacteria to survive and exert the probiotic effects in gastrointestinal tract. InB. longumBBMN68, the MarR-type regulator BmrR was involved in bile stress response by auto-regulatingbmrRABoperon and ox-bile as an inducer could increase the expression of BmrAB transporter to enhance the bile tolerance of BBMN68.This is the first report about functional analysis ofbmrRABoperon in bile stress response, which will provide new insight into bile tolerance mechanisms inBifidobacteriumand other bacteria.

Yak milk is a type of milk that people are less familiar with due to its remote geographical location, the particular geographical environment and climatic conditions in Tibet, which may have significant effects on composition, microbiota and fermentation outcome. To investigate the chemical composition and microbiota of fresh and fermented yak milk, and to isolate and characterize the predominant microorganisms in the fermented milk, yak milk (24 fresh and 30 fermented milk samples) was collected from four areas of different altitudes in Tibet, and their microbiological profile and chemical composition were investigated. Yak milk had a higher fat, crude protein, lactose and dry matter content than cow milk. The fermented yak milk showed a great diversity in fat and dry matter levels due to the different ways of processing in different localities, and lower pH and higher lactic acid content compared with commercial cow milk yogurt. Fermented yak milk had a better sanitary quality than fresh yak milk. Three species of lactobacilli (Lactobacillus fermentum, Lactobacillus helveticus and Lactobacillus curvatus) and five species of yeast (Saccharomyces cerevisiae, Candida kefyr, Candida lambica, Candida famata and Candida holmii) were identified phenotypically and encountered as predominant fermentation microbiota. The predominant lactic species in fermented milk was L. fermentum.

Asia differs substantially among and within its regions populated by diverse ethnic groups, which maintain their own respective cultures and dietary habits. To address the diversity in their gut microbiota, we characterized the bacterial community in fecal samples obtained from 303 school-age children living in urban or rural regions in five countries spanning temperate and tropical areas of Asia. The microbiota profiled for the 303 subjects were classified into two enterotype-like clusters, each driven by Prevotella (P-type) or Bifidobacterium/Bacteroides (BB-type), respectively. Majority in China, Japan and Taiwan harbored BB-type, whereas those from Indonesia and Khon Kaen in Thailand mainly harbored P-type. The P-type microbiota was characterized by a more conserved bacterial community sharing a greater number of type-specific phylotypes. Predictive metagenomics suggests higher and lower activity of carbohydrate digestion and bile acid biosynthesis, respectively, in P-type subjects, reflecting their high intake of diets rich in resistant starch. Random-forest analysis classified their fecal species community as mirroring location of resident country, suggesting eco-geographical factors shaping gut microbiota. In particular, children living in Japan harbored a less diversified microbiota with high abundance of Bifidobacterium and less number of potentially pathogenic bacteria, which may reflect their living environment and unique diet.

In this paper, two statistical methods were applied to optimize medium components to improve the production of the milk-clotting enzyme by Bacillus amyloliquefaciens D4. First, wheat bran juice, skim milk powder, and Na2HPO4 were shown to have significant effects on D4 enzyme production using the Plackett?Burman experimental design. Subsequently, an optimal medium was obtained using the Box?Behnken method, which consisted of 3.31 g/l of skim milk powder, 5.0 g/l of sucrose, 0.1 g/l of FeSO4?7H2O, 0.1 g/l of MgSO4?7H2O, 0.1 g/l of MnSO4?2H2O, 0.1 g/l of ZnSO4?7H2O, 1.52 g/l of Na2HPO4, and 172.45 g/l of wheat bran juice. With this optimal medium, the milk-clotting enzyme production was remarkably enhanced. The milk-clotting enzyme activity reached 3,326.7 SU/ml after incubation of 48 h, which was 1.76-fold higher than that of the basic medium, showing that the Plackett?Burman design and Box?Behnken response surface method are effective to optimize medium components, and B. amyloliquefaciens D4 possessed a high rennet-producing capacity in the optimal medium.

Antioxidant and antimicrobial properties of 10 Chinese medicinal herb extracts were evaluated by dipping raw sheep meat in extracts, packaging the samples in polyethylene, and refrigerating them at 4 degrees C. The optimum concentrations of Codonopsis pilosula, Platycodon grandiflorum, Artemisia capillaris, Cinnamomum cassia, Rheum palmatum, Ziziphus jujuba, Gardenia jasminoides, Santalum album, Angelica sinensis, and Bletilla striata were 0.10, 0.10, 0.25, 0.10, 0.25, 0.25, 0.25, 0.10, 0.25, and 0.25%, respectively. Analysis revealed that test ingredients were more effective in reducing lipid oxidation and microbial counts in raw sheep meat. Correlation analysis revealed a significant negative linear relationship between the inhibition of hydroxyl and lipid oxidation, and inhibition of hydroxyl was the main factor affecting lipid oxidation. A. capillaris (0.25%), C. pilosula (0.10%), and P. grandiflorum (0.10%) were identified as the most effective antioxidants. S. album (0.10%), A. capillaris (0.10%), and C. cassia (0.10%) were the most effective antimicrobials. A. capillaris (0.25%), C. pilosula (0.10%), and P. grandiflorum (0.10%) increased meat redness significantly (P0.05) when compared with the control samples on days 0, 3, 5, 7, 9, 10, and 11. The pH values of sheep meat treated with C. pilosula (0.10%) and A. capillaris (0.10%) were lower than those of meat treated with other extracts.

One hundred and twelve samples of raw buffalo milk were collected at four locations in China, and their microbiological and chemical composition was analyzed. Average levels of major components were: fat 7.59% (v/v), crude protein 4.86% (w/w), lactose 4.74% (w/w), total solids 18.44% (w/w), ash 0.85% (w/w), and pH 6.65. The crude protein, fat, total solids and ash contents of milk from multi-crossbreed buffalo were higher than those of river buffalo’s, but lower than those of crossbreed F 1 and F 2 buffalo’s. Microbiological enumeration revealed counts of total mesophilic aerobic bacteria of 5.59 log cfu/ml, bacterial endospores 2.31, lactic acid bacteria 4.62, fungi 1.79, coliforms 2.42, Escherichia coli 1.53, and Staphylococcus aureus 1.68. Listeria spp. were below detection level in all of the samples. The microbiological quality of buffalo milk was judged marginal and indicates the need for improved hygienic standards.

The immunoactivity was evaluated of Dendrobium officinale Kimura & Migo, a Chinese herbal plant, and its crude polysaccharides. Different dosages of D. officinale and its polysaccharides were orally administered to healthy BALB/c mice. The control group was given distilled water. After 4 weeks, immune parameters, including cellular immunity (delayed-type hypersensitivity and natural killer cell activity), humoral immunity (serum hemolytic complement activity), nonspecific immunity (peritoneal macrophage phagocytosis) and interferon-γ production by splenocytes were measured. The results showed that D. officinale and its polysaccharides can significantly enhance cellular immunity and nonspecific immunity in mice. Humoral immunity was also enhanced after oral administration of D. officinale, but the polysaccharides had no influence. Both D. officinale and its polysaccharides markedly increased IFN-γ production by murine splenocytes. Six fractions were isolated from the polysaccharides; the molecular weight of the major fraction was 533,700 Da, and composed of mannose, glucose and rhamnose in a molar ratio of 7.3:1.3:1.0.