Effect of Oat ß-Glucan on the Rheological Characteristics and Microstructure of Set-Type Yogurt.

The oat ß-glucan (OG) was added into set-type yogurt as a functional ingredient, in order to evaluate effects on the rheological characteristics and microstructure of set-type yogurt. When the OG concentration increased from 0 to 0.3%, the WHC gradually increased. At 0.3% OG, the set-type yogurt had the highest WHC of 94.67%. Additionally, the WHC continuously decreased, reaching the lowest WHC (about 80%) at 0.5% OG. When 0.3% OG was added, the highest score of sensory evaluation was about 85. The rheological result showed that the fermentation process went through the changes as follows: solid → liquid → solid → liquid. The addition of 0.3% OG decreased the fermentation time of set-type yogurt by about 16 min, making yogurt more inclined to be liquid. The acidity of set-type yogurt with OG was slightly higher. The result of microstructure showed that the addition of OG destroyed the three-dimensional network structure of yogurt, and some spherical aggregate particles could be clearly observed at 0.3% OG. Overall, this study provided a theoretical basis for the application of OG in set-type yogurt.

Dynamic changes of yak (Bos grunniens) gut microbiota during growth revealed by polymerase chain reaction-denaturing gradient gel electrophoresis and metagenomics.

OBJECTIVE: To understand the dynamic structure, function, and influence on nutrient metabolism in hosts, it was crucial to assess the genetic potential of gut microbial community in yaks of different ages. METHODS: The denaturing gradient gel electrophoresis (DGGE) profiles and Illumina-based metagenomic sequencing on colon contents of 15 semi-domestic yaks were investigated. Unweighted pairwise grouping method with mathematical averages (UPGMA) clustering and principal component analysis (PCA) were used to analyze the DGGE fingerprint. The Illumina sequences were assembled, predicted to genes and functionally annotated, and then classified by querying protein sequences of the genes against the Kyoto encyclopedia of genes and genomes (KEGG) database. RESULTS: Metagenomic sequencing showed that more than 85% of ribosomal RNA (rRNA) gene sequences belonged to the phylum Firmicutes and Bacteroidetes, indicating that the family Ruminococcaceae (46.5%), Rikenellaceae (11.3%), Lachnospiraceae (10.0%), and Bacteroidaceae (6.3%) were dominant gut microbes. Over 50% of non-rRNA gene sequences represented the metabolic pathways of amino acids (14.4%), proteins (12.3%), sugars (11.9%), nucleotides (6.8%), lipids (1.7%), xenobiotics (1.4%), coenzymes, and vitamins (3.6%). Gene functional classification showed that most of enzyme-coding genes were related to cellulose digestion and amino acids metabolic pathways. CONCLUSION: Yaks' age had a substantial effect on gut microbial composition. Comparative metagenomics of gut microbiota in 0.5-, 1.5-, and 2.5-year-old yaks revealed that the abundance of the class Clostridia, Bacteroidia, and Lentisphaeria, as well as the phylum Firmicutes, Bacteroidetes, Lentisphaerae, Tenericutes, and Cyanobacteria, varied more greatly during yaks' growth, especially in young animals (0.5 and 1.5 years old). Gut microbes, including Bacteroides, Clostridium, and Lentisphaeria, make a contribution to the energy metabolism and synthesis of amino acid, which are essential to the normal growth of yaks.

Cholesterol gallstones and bile host diverse bacterial communities with potential to promote the formation of gallstones.

The prevalence of cholesterol gallstones has increased in recent years. Bacterial infection correlates with the formation of gallstones. We studied the composition and function of bacterial communities in cholesterol gallstones and bile from 22 cholesterol gallstone patients using culture-dependent and culture-independent methods. Altogether fourteen and eight bacterial genera were detected in cholesterol gallstones and bile, respectively. Pseudomonas spp. were the dominant bacteria in both cholesterol gallstones and bile. As judged by diversity indices, hierarchical clustering and principal component analysis, the bacterial communities in gallstones were different from those in bile. The gallstone microbiome was considered more stable than that of bile. The different microbial communities may be partially explained by differences in their habitats. We found that 30% of the culturable strains from cholesterol gallstones secreted ß-glucuronidase and phospholipase A2. Pseudomonas aeruginosa strains showed the highest ß-glucuronidase activity and produced the highest concentration of phospholipase A2, indicating that Ps. aeruginosa may be a major agent in the formation of cholesterol gallstones.

Dynamics of microbial community and changes of metabolites during production of type Ι sourdough steamed bread made by retarded sponge-dough method.

Dynamics of microbial community and changes of metabolites during production of type Ι sourdough steamed bread made by retarded sponge-dough method (SSB) were studied. Lactobacillus sanfranciscensis and Lactobacillus pontis were the dominant bacterial species. Particularly, relative abundances of Lactobacillus sanfranciscensis were significantly higher than that of other sub-dominant bacterial species. The dominant fungal species were Saccharomyces cerevisiae and Kazachstania humilis, and the latter was the most predominant. A stable bacterial and fungal consortia was established in sponge dough retarded from 12 to 24 h and main dough proofed from 30 to 60 min. Metabolism preference for maltose of Lactobacillus sanfranciscensis favoured a mutualistic association with maltose-negative Kazachstania humilis, and hence contributing to their competitiveness and dominance. Volatile compounds became more abundant with much more esters as sponge retarding time extended. Probably, the accumulation of organic acids and ethanol contributed mostly to formation of ethyl esters in sponge dough during retarding.

[Toxicity of alpha-amanitin on mice in vivo].

OBJECTIVE: To study the toxic effect of alpha-amanitin from Amanita fungi on mice in vivo. METHODS: The LD50 of alpha-amanitin was determined with intravenous and intraperitoneal injections of alpha-amanitin. The mice were then injected intravenously with LD50 dose of alpha-amanitin, and the viscera index was evaluated. The peripheral blood samples were collected 24 hours later to measure the hemogram and biochemical indicators. The histological changes of internal organs were examined. The alpha-amanitin in organ tissues were measured. RESULTS: The intraperitoneal and intravenous LD50 doses of alpha-amanitin were 0.742 mg/kg and 0.327 mg/kg bodyweight, respectively. The WBC, RBC and Hb decreased significantly, whereas the serum BUN and Crea increased significantly. The serum ALT, AST, TBIL and DBIL increased to 24.0, 9.6, 26.3 and 37.0 times of the levels of controls, respectively, 24 hour after the injection. The viscera indexes of liver and kidney also increased significantly, and focal necrosis was found in the tissue slices 48 hours after the injection. The poison compound alpha-amanitin was detected in liver and kidney tissue homogenates by RP-HPLC 48 hours after the injection. CONCLUSION: Serum BUN, Crea, ALT, AST, TBIL and DBIL are sensitive indicators for the toxicity of alpha-amanitin in vivo. The pathological changes of liver and kidney are very serious. The cyclopeptide alpha-amanitin could reside in the two organs for a long last toxic effect.

Effects of Pleurotus eryngii (mushroom) powder and soluble polysaccharide addition on the rheological and microstructural properties of dough.

Adding a certain proportion of Pleurotus eryngii can improve the nutritional value of wheat-flour foods and enhance the utilization of this mushroom. In this research, partial wheat flour was substituted with P. eryngii powder (PEP) or soluble polysaccharide (SPPE) at different addition levels, and the effects of PEP and SPPE on the rheological and microstructural properties of dough were investigated. Farinographic assay results suggested that PEP significantly (p < 0.05) increased the water absorption of wheat flour but decreased the development time and stability of dough significantly (p < 0.05). Furthermore, it was capable of providing weaker extensographic characteristics and harder dough with the increasing of PEP addition levels. The dynamic oscillatory tests indicated that the PEP addition approximately increased the storage (G') and loss (G″) moduli in the entire frequency range, while the tan δ roughly decreased with the increasing of PEP addition levels, which could be attributed to the low solubility and strong water-trapping capacity of the dietary fiber in PEP. Due to the good water solubility and easy formation of hydrogen bonds, the addition of SPPE had inconsistent results with the PEP addition. The inner microstructure of dough showed that the continuity of gluten networks had been disrupted by PEP and SPPE addition and then resulted in a weaker extension and harder dough. This research could provide a foundation for the application of PEP in wheat-flour foods, and PEP addition levels of 2.5%-5.0% are recommended.

Diversified gut microbiota in newborns of mothers with gestational diabetes mellitus.

Gestational diabetes mellitus (GDM), a high-risk pregnancy complication of great effect on the perinatal health of women and newborns, may cause changes of gut microbiota in mothers and further affect gut microbiota in newborns. This study aimed to investigate the potential effect of mother GDM on newborns' gut microbiota. Meconium DNA was extracted from a total of 34 full-term and C-sectioned newborns, in which 20 newborns had mothers diagnosed with GDM, while 14 had unaffected mothers. Sequencing and bioinformatics analysis of 16S rRNA indicated that the gut microbiota of GDM newborns showed differences compared to control newborns. The taxonomy analyses suggested that the overall bacterial content significantly differed by maternal diabetes status, with the microbiome of the GDM group showing lower alpha-diversity than that of control group. The phyla of Proteobacteria and Actinobacteria in GDM newborns increased, while that of Bacteroidetes significantly reduced (P<0.05). Moreover, several unique gut microbiota in phylum of Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Chloroflexi, Acidobacteria, and Planctomycetes found in control newborns were absent in GDM ones. At genus level, the relative abundance of Prevotella and Lactobacillus significantly decreased (P<0.05) in GDM newborns. Correlation analysis indicated that maternal fasting glucose levels were positively correlated with the relative abundance of phylum Actinobacteria and genus Acinetobacter, while negatively correlated with that of phylum Bacteroidetes and genus Prevotella. However, bacteria in GDM grade A2 (GDM_A2) newborns did not show any statistical variation compared to those from control newborns, which might be attributed to the additional intervention by insulin. The results of this study have important implications for understanding the potential effects of GDM on the gut microbiota of newborns and thus possibly their metabolism at later stages in their lives.

KH-type splicing regulatory protein is regulated by nuclear factor-κB signaling to mediate innate immunity in Caco-2 cells infected by Salmonella enteritidis.

Salmonella enteritidis infection occurs in enterogenous diseases, such as gastroenteritis and parenteral focal infection, which often involve inflammation of intestinal epithelial cells. The nuclear factor kappa B (NF-κB) pathway participates in the innate immune response to many gram-negative pathogenic bacteria and initiates inflammation in epithelial cells. KH-type splicing regulatory protein (KSRP) is a multi-domain RNA-binding protein that recruits the exosome-containing mRNA degradation complex to mRNAs coding for inflammatory response factors. However, it remains unclear whether KSRP is regulated by NF-κB signaling pathway in response to S. enteritidis infection and affects the development of inflammation. Accordingly, in this study, we investigated the role of KSRP in mediating the response to S. enteritidis in Caco-2 cells. The data revealed that S. enteritidis infection decreased KSRP expression, which was suppressed by blocking the NF-κB pathway. Additionally, S. enteritidis infection significantly increased the expression of inducible nitric oxide synthase and cyclooxygenase-2. Overexpression of KSRP reduced the expression levels of inflammatory factors in Caco-2 cells. KSRP was regulated by the NF-κB signaling pathway and participated in mediating the innate immune response to S. enteritidis infection in Caco-2 cells, and KSRP acted as a negative regulator of inflammatory gene expression.

Vitamin D Signaling through Induction of Paneth Cell Defensins Maintains Gut Microbiota and Improves Metabolic Disorders and Hepatic Steatosis in Animal Models.

Metabolic syndrome (MetS), characterized as obesity, insulin resistance, and non-alcoholic fatty liver diseases (NAFLD), is associated with vitamin D insufficiency/deficiency in epidemiological studies, while the underlying mechanism is poorly addressed. On the other hand, disorder of gut microbiota, namely dysbiosis, is known to cause MetS and NAFLD. It is also known that systemic inflammation blocks insulin signaling pathways, leading to insulin resistance and glucose intolerance, which are the driving force for hepatic steatosis. Vitamin D receptor (VDR) is highly expressed in the ileum of the small intestine, which prompted us to test a hypothesis that vitamin D signaling may determine the enterotype of gut microbiota through regulating the intestinal interface. Here, we demonstrate that high-fat-diet feeding (HFD) is necessary but not sufficient, while additional vitamin D deficiency (VDD) as a second hit is needed, to induce robust insulin resistance and fatty liver. Under the two hits (HFD+VDD), the Paneth cell-specific alpha-defensins including α-defensin 5 (DEFA5), MMP7 which activates the pro-defensins, as well as tight junction genes, and MUC2 are all suppressed in the ileum, resulting in mucosal collapse, increased gut permeability, dysbiosis, endotoxemia, systemic inflammation which underlie insulin resistance and hepatic steatosis. Moreover, under the vitamin D deficient high fat feeding (HFD+VDD), Helicobacter hepaticus, a known murine hepatic-pathogen, is substantially amplified in the ileum, while Akkermansia muciniphila, a beneficial symbiotic, is diminished. Likewise, the VD receptor (VDR) knockout mice exhibit similar phenotypes, showing down regulation of alpha-defensins and MMP7 in the ileum, increased Helicobacter hepaticus and suppressed Akkermansia muciniphila. Remarkably, oral administration of DEFA5 restored eubiosys, showing suppression of Helicobacter hepaticus and increase of Akkermansia muciniphila in association with resolving metabolic disorders and fatty liver in the HFD+VDD mice. An in vitro analysis showed that DEFA5 peptide could directly suppress Helicobacter hepaticus. Thus, the results of this study reveal critical roles of a vitamin D/VDR axis in optimal expression of defensins and tight junction genes in support of intestinal integrity and eubiosis to suppress NAFLD and metabolic disorders.

Post-mortem oxidative stability of three yak (Bos grunniens) muscles as influenced by animal age.

The influence of animal age and muscle source on the oxidative stability of yak steaks was examined. Longissimus thoracis (LT) muscles from yaks of different age groups (0.5, 1.5, 2.5, and 3.5 years), and three muscle sources of LT, Psoas major (PM), and Biceps femoris (BF) from yaks of 0.5, 1.5, and 2.5 years, were evaluated for metmyoglobin content, activity of antioxidant enzymes, and antioxidant capacity. Oxidative stability was influenced (P<0.05) by muscle source and animal age. LT steaks from 0.5, 1.5, and 2.5 year old yaks exhibited lower (P<0.05) metmyoglobin content than their PM and BF counterparts. Furthermore, LT steaks from 3.5 year old yaks demonstrated lower (P<0.05) metmyoglobin content and greater (P<0.05) activities of antioxidant enzymes than LT steaks from other age groups. These results indicated the necessity to develop muscle- and age-specific processing strategies to improve color and oxidative stability of yak meat.

Purification and anticancer activity investigation of pentacyclic triterpenoids from the leaves of Sinojackia sarcocarpa L.Q. Luo by high-speed counter-current chromatography.

Sinojackia sarcocarpa L.Q. Luo has high aesthetic value, which is clinically used to treat diseases such as the variations of arthritis, thromboangiitis obliterans, angina pectoris as well as many other diseases. Pentacyclic triterpenoids are the main pharmacological effective compounds. High-speed counter-current chromatography method was performed on a Midi-DE centrifuge at 25°C. The solvent system was n-hexane-ethylacetate-methanol-water (10:5:3:1, v/v). Peak fractions were collected according to the elution profile for subsequent high-performance liquid chromatography analysis. The structure identification was performed by ultraviolet, infrared, mass spectrometry, (1)H-NMR and (13)C-NMR. Compound 2α,3α,19ß,23ß-tetrahydroxyurs-12-en-28-oic acid and 2α,3α,23ß-trihydroxyurs-12-en-28-oic acid were purified from the plant of Styracaceaen genius for the first time, whose purities were 96.57% and 97.33%, respectively. Compared with the same dose of oral 5-fluorouracil with 57.6% inhibition rate, the S(180) tumour inhibition rates of 20 mg kg(-1)d(-1) two compounds were 59.5% and 48.9%, respectively.

Immobilization of silver nanoparticles onto sulfonated polyethersulfone membranes as antibacterial materials.

By using the interaction between the sulfonated groups and silver ions, silver nanoparticles were successfully introduced onto the surface of sulfonated polyethersulfone (SPES) membranes by using vitamin C as reducing agent. The presence of silver nanoparticles on the surface of the PES/SPES hybrid membranes was characterized by UV spectrophotometer, scanning electron microscopy and transmission electron microscopy. Detailed studies on the antibacterial activity of the (PES/SPES)-Ag composites were carried out for Staphylococcus aureus, Staphylococcus albus, and Escherichia coli, for which, the composites exhibited significantly inhibition capacity. Cytocompatibility of the (PES/SPES)-Ag composites were also investigated by cell cytotoxicity and cell adhesion tests. The results indicated that after immobilizing with silver nanoparticles, the (PES/SPES)-Ag was still within the safe use range. To our knowledge, this is the first time that PES membranes have been prepared with antibacterial capacity. We anticipate that this novel and green method might lead to an expanded usage of PES with antibacterial properties in medical instruments and food processing industries in the future, and might also make a potential contribution to the fields of antibacterial chemistry.