Perinatal treatment of parents with the broad-spectrum antibiotic enrofloxacin aggravates contact sensitivity in adult offspring mice.

BACKGROUND: Antibiotics, while eliminating pathogens, also partially deplete commensal bacteria. Antibiotic-induced dysbiosis may contribute to the observed rise in "immune-mediated" diseases, including autoimmunity and allergy. The aim of this study is to investigate the impact of perinatal antibiotic treatment on T cell-mediated immune response in adult mice. METHODS: Oral treatment with broad-spectrum antibiotic enrofloxacin during gestation and breastfeeding or breastfeeding or gestation alone was used to evaluate whether antibiotic exposure early in life could modulate contact sensitivity (CS) in adult mice. RESULTS: Here, we demonstrated that enrofloxacin treatment during gestation and breastfeeding, but not during pregnancy or breastfeeding alone, aggravated CS reaction in adult mice measured by ear swelling. These data correlate with increased myeloperoxidase (MPO) activity in the ear extracts and elevated production of IL-6 and IL-17A by auricular lymph node cells (ELNC) and was not influenced by food consumption and body weight. In each dosing regimen, enrofloxacin treatment reduced the relative abundance of Enterococcus spp. but did not influence the relative abundances of Lactobacillus, Clostridium cluster XIVa, XIVab, I, Bacteroidetes, and segmented filamentous bacteria (SFB). However, prolonged enrofloxacin-treatment during both gestation and breastfeeding decreased the relative abundance of Clostridium cluster IV. CONCLUSION: These data show that long-term perinatal enrofloxacin treatment induces intestinal dysbiosis, characterized by decreased levels of anti-inflammatory Clostridium cluster IV, and alters T cell-dependent immune responses, enhancing CS reaction in adult mice.

Gut microbiome of treatment-naïve MS patients of different ethnicities early in disease course.

Although the intestinal microbiome has been increasingly implicated in autoimmune diseases, much is unknown about its roles in Multiple Sclerosis (MS). Our aim was to compare the microbiome between treatment-naïve MS subjects early in their disease course and controls, and between Caucasian (CA), Hispanic (HA), and African American (AA) MS subjects. From fecal samples, we performed 16S rRNA V4 sequencing and analysis from 45 MS subjects (15 CA, 16 HA, 14 AA) and 44 matched healthy controls, and whole metagenomic shotgun sequencing from 24 MS subjects (all newly diagnosed, treatment-naïve, and steroid-free) and 24 controls. In all three ethnic groups, there was an increased relative abundance of the same single genus, Clostridium, compared to ethnicity-matched controls. Analysis of microbiota networks showed significant changes in the network characteristics between combined MS cohorts and controls, suggesting global differences not restricted to individual taxa. Metagenomic analysis revealed significant enrichment of individual species within Clostridia as well as particular functional pathways in the MS subjects. The increased relative abundance of Clostridia in all three early MS cohorts compared to controls provides candidate taxa for further study as biomarkers or as etiologic agents in MS.

Dose Effects of Orally Administered Spirulina Suspension on Colonic Microbiota in Healthy Mice.

Oral supplemented nutraceuticals derived from food sources are surmised to improve the human health through interaction with the gastrointestinal bacteria. However, the lack of fundamental quality control and authoritative consensus (e.g., formulation, route of administration, dose, and dosage regimen) of these non-medical yet bioactive compounds are one of the main practical issues resulting in inconsistent individual responsiveness and confounded clinical outcomes of consuming nutraceuticals. Herein, we studied the dose effects of widely used food supplement, microalgae spirulina (Arthrospira platensis), on the colonic microbiota and physiological responses in healthy male Balb/c mice. Based on the analysis of 16s rDNA sequencing, compared to the saline-treated group, oral administration of spirulina once daily for 24 consecutive days altered the diversity, structure, and composition of colonic microbial community at the genus level. More importantly, the abundance of microbial taxa was markedly differentiated at the low (1.5 g/kg) and high (3.0 g/kg) dose of spirulina, among which the relative abundance of Clostridium XIVa, Desulfovibrio, Eubacterium, Barnesiella, Bacteroides, and Flavonifractor were modulated at various degrees. Evaluation of serum biomarkers in mice at the end of spirulina intervention showed reduced the oxidative stress and the blood lipid levels and increased the level of appetite controlling hormone leptin in a dose-response manner, which exhibited the significant correlation with differentially abundant microbiota taxa in the cecum. These findings provide direct evidences of dose-related modulation of gut microbiota and physiological states by spirulina, engendering its future mechanistic investigation of spirulina as potential sources of prebiotics for beneficial health effects via the interaction with gut microbiota.

Probiotic supplementation restores normal microbiota composition and function in antibiotic-treated and in caesarean-born infants.

BACKGROUND: Infants born by caesarean section or receiving antibiotics are at increased risk of developing metabolic, inflammatory and immunological diseases, potentially due to disruption of normal gut microbiota at a critical developmental time window. We investigated whether probiotic supplementation could ameliorate the effects of antibiotic use or caesarean birth on infant microbiota in a double blind, placebo-controlled randomized clinical trial. Mothers were given a multispecies probiotic, consisting of Bifidobacterium breve Bb99 (Bp99 2 × 108 cfu) Propionibacterium freundenreichii subsp. shermanii JS (2 × 109cfu), Lactobacillus rhamnosus Lc705 (5 × 109 cfu) and Lactobacillus rhamnosus GG (5 × 109 cfu) (N = 168 breastfed and 31 formula-fed), or placebo supplement (N = 201 breastfed and 22 formula-fed) during pregnancy, and the infants were given the same supplement. Faecal samples of the infants were collected at 3 months and analyzed using taxonomic, metagenomic and metaproteomic approaches. RESULTS: The probiotic supplement had a strong overall impact on the microbiota composition, but the effect depended on the infant's diet. Only breastfed infants showed the expected increase in bifidobacteria and reduction in Proteobacteria and Clostridia. In the placebo group, both birth mode and antibiotic use were significantly associated with altered microbiota composition and function, particularly reduced Bifidobacterium abundance. In the probiotic group, the effects of antibiotics and birth mode were either completely eliminated or reduced. CONCLUSIONS: The results indicate that it is possible to correct undesired changes in microbiota composition and function caused by antibiotic treatments or caesarean birth by supplementing infants with a probiotic mixture together with at least partial breastfeeding. TRIAL REGISTRATION: clinicaltrials.gov NCT00298337 . Registered March 2, 2006.

Relationship between fatty acids intake and Clostridium coccoides in obese individuals with metabolic syndrome.

Dietary habits exert a strong influence on gut microbial composition and may result in an imbalance of gut microbes, representing a predisposition to obesity and metabolic disorders. We aimed to investigate a potential relationship between gut bacterial species and metabolic parameters and dietary intake. Bacterial DNA was extracted from feces of 34 obese subjects with and without metabolic syndrome (MS and n-MS group, respectively). We then used real-time polymerase chain reaction (qPCR) for quantifying specific sequences to Akkermansia muciniphila, Bifidobacterium spp., Clostridium coccoides, and Lactobacillus spp. and analyzed them with respect to clinical characteristics. Our data showed that the MS group had a 6.7-fold higher level of C. coccoides in their stool samples than the n-MS group. The abundance of C. coccoides was positively correlated with a high intake of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids. Furthermore, an excessive dietary level of MUFA was identified as a predictor of C. coccoides abundance. Alterations in the gut microbial ecology were positively correlated with levels of triacylglycerol in obese individuals. Therefore, the type and quantity of dietary fat may alter the gut microbial ecology in obese individuals with MS and may predispose them to dyslipidemia.

The Impact of Long-Term Intake of Phenolic Compounds-Rich Grape Pomace on Rat Gut Microbiota.

The aim of this work is to evaluate the impact on the rat microbiota of long-term feeding with phenolic compounds (PC) rich grape pomace extracts. Thirty, 2-mo-old rats, were divided into 5 groups. Four groups were treated with different concentrations of PC (2.5, 5, 10, and 20 mg/kg/d diluted in 0.1% DMSO), and 1 group received 0.1% Dimethyl Sulfoxide (DMSO) alone (control group). The daily treatment lasted 14 mo. Major phenolic compounds constituents were characterized by the high-performance liquid chromatography and free radical scavenging capacity was measured by means of the DPPH assay. Fecal samples from young rats (2-mo old), and rats daily fed with PC or DMSO were collected at 6 and 14 mo posttreatment. The gut microbiota composition was analyzed by quantitative polymerase chain reaction. Bifidobacterium was significantly higher in the groups PC 2.5 and PC 5 than in control and young rats. Lactobacillus decreased with time in all treated and untreated groups. Bacteroides, Clostridium leptum subgroup (Clostridium cluster IV), and Enterococcus were not significantly changed by PC at any concentration when compared to control; nevertheless, after 14 mo of treatment all concentrations of PC abolished the increase of Clostridium sensu stricto (cluster I) (Clostridium Cluster I) observed in the control group when compared to young rats. PC do modulate selectively rat gut microbiome to a healthier phenotype in long-term feeding rats, and could counteract the adverse outcomes of aging on gut bacterial population. PRACTICAL APPLICATION: This research shows that phenolic-rich grape pomace extracts exhibiting a high antioxidant activity, selectively modulate rat gut microbiota to a healthier phenotype within age in a long-term feeding rats.

Glucerabacter canisensis gen. nov., sp. nov., isolated from dog feces and its effect on the hydrolysis of plant glucosylceramide in the intestine of dogs.

A Gram-positive, obligately anaerobic, oval-rod shaped, non-spore-forming, and non-pigmented bacterium, designated strain NATH-2371T (= JCM31739T = DSM105698T), was isolated from dog feces. Comparative 16S rRNA gene sequence analysis revealed that strain NATH-2371T belongs to Clostridium cluster XIVa, and the closest strains were Coprococcus comes ATCC 27758T (94.8% 16S rRNA gene sequence similarity) and Clostridium nexile DSM 1787T (94.0%). Strain NATH-2371T produced acetate, formate, and ethanol from glucose. Predominant cellular fatty acids are C16:0 and C16:0 DMA. On the basis of the phenotypic and genotypic differences, strain NATH-2371T represents a novel species in a new genus of the family Lachnospiraceae, for which the name Glucerabacter canisensis gen. nov., sp. nov., is proposed. This strain was found to efficiently hydrolyze plant glucosylceramide (GluCer). The abundance of strain NATH-2371T in dog feces was higher in young dogs than in old dogs. Incubation of dog fecal bacteria showed that GluCer-hydrolyzing activity decreased with the age of dogs. The cell number of strain NATH-2371T in dog feces appeared to be correlated with GluCer hydrolysis. Thus, this bacterium is likely to play a major role in GluCer hydrolysis in the dog intestine.

Antimicrobial-resistant Faecal Organisms in Algae Products Marketed as Health Supplements.

Dietary supplements are increasingly popular in Irish society. One of these is blue-green algae which is used with a variety health benefits in mind. A batch of Chlorella powder was found to be contaminated with Salmonella species in Ireland in 2015. This prompted additional testing of a total of 8 samples of three different products (Chlorella, Spirulina and Super Greens), for other faecal flora and antimicrobial resistance in any bacteria isolated. All 8 samples cultured enteric flora such as Enterococci, Enterobacteriaceae and Clostridium species. Antimicrobial susceptibility testing revealed one isolate with extended-spectrum ?-lactamase (ESBL) activity and one with carbapenemase activity. Clinicians caring for vulnerable patients should be aware of the potential risk of exposure to antimicrobial resistant bacteria associated with these products.

Iron in Micronutrient Powder Promotes an Unfavorable Gut Microbiota in Kenyan Infants.

Iron supplementation may have adverse health effects in infants, probably through manipulation of the gut microbiome. Previous research in low-resource settings have focused primarily on anemic infants. This was a double blind, randomized, controlled trial of home fortification comparing multiple micronutrient powder (MNP) with and without iron. Six-month-old, non- or mildly anemic, predominantly-breastfed Kenyan infants in a rural malaria-endemic area were randomized to consume: (1) MNP containing 12.5 mg iron (MNP+Fe, n = 13); (2) MNP containing no iron (MNP-Fe, n = 13); or (3) Placebo (CONTROL, n = 7), from 6-9 months of age. Fecal microbiota were profiled by high-throughput bacterial 16S rRNA gene sequencing. Markers of inflammation in serum and stool samples were also measured. At baseline, the most abundant phylum was Proteobacteria (37.6% of rRNA sequences). The proteobacterial genus Escherichia was the most abundant genus across all phyla (30.1% of sequences). At the end of the intervention, the relative abundance of Escherichia significantly decreased in MNP-Fe (-16.05 ± 6.9%, p = 0.05) and CONTROL (-19.75 ± 4.5%, p = 0.01), but not in the MNP+Fe group (-6.23 ± 9%, p = 0.41). The second most abundant genus at baseline was Bifidobacterium (17.3%), the relative abundance of which significantly decreased in MNP+Fe (-6.38 ± 2.5%, p = 0.02) and CONTROL (-8.05 ± 1.46%, p = 0.01), but not in MNP-Fe (-4.27 ± 5%, p = 0.4445). Clostridium increased in MNP-Fe only (1.9 ± 0.5%, p = 0.02). No significant differences were observed in inflammation markers, except for IL-8, which decreased in CONTROL. MNP fortification over three months in non- or mildly anemic Kenyan infants can potentially alter the gut microbiome. Consistent with previous research, addition of iron to the MNP may adversely affect the colonization of potential beneficial microbes and attenuate the decrease of potential pathogens.

Enrichment of sulfidogenic bacteria from the human intestinal tract.

Hydrogen sulfide is formed in the human intestinal tract as the end product of the anaerobic microbial degradation of sulfur compounds present in mucus, bile or proteins. Since human gut microbial sulfur metabolism has been poorly characterized, we aimed to identify and isolate the microorganisms involved in sulfide formation. Fresh fecal samples from one healthy donor and one diagnosed with irritable bowel syndrome were used as inocula for enrichments that were supplemented with sulfate or sulfite as electron acceptors in combination with different electron donors. After two transfers, cultures with high sulfide production were selected and the phylogenetic composition of the enriched microbial communities was determined. Sulfite respiration and cysteine degradation were the dominant sulfidogenic processes, and the most abundant bacteria enriched belonged to Bilophila and Clostridium cluster XIVa. Different isolates were obtained and remarkably included a novel sulfite reducer, designated strain 2C. Strain 2C belongs to the Veillonellaceae family of Firmicutes phylum and showed limited (91%) 16S rRNA gene sequence similarity with that of known Sporomusa species and hence may represent a novel genus. This study indicates that bacteria that utilize sulfite and organic sulfur compounds rather than merely sulfate are relevant for human intestinal sulfur metabolism.

Sex differences in colonization of gut microbiota from a man with short-term vegetarian and inulin-supplemented diet in germ-free mice.

Gnotobiotic mouse model is generally used to evaluate the efficacy of gut microbiota. Sex differences of gut microbiota are acknowledged, yet the effect of recipient's gender on the bacterial colonization remains unclear. Here we inoculated male and female germ-free C57BL/6J mice with fecal bacteria from a man with short-term vegetarian and inulin-supplemented diet. We sequenced bacterial 16S rRNA genes V3-V4 region from donor's feces and recipient's colonic content. Shannon diversity index showed female recipients have higher bacteria diversity than males. Weighted UniFrac principal coordinates analysis revealed the overall structures of male recipient's gut microbiota were significantly separated from those of females, and closer to the donor. Redundancy analysis identified 46 operational taxonomic units (OTUs) differed between the sexes. The relative abundance of 13 OTUs were higher in males, such as Parabacteroides distasonis and Blautia faecis, while 33 OTUs were overrepresented in females, including Clostridium groups and Escherichia fergusonii/Shigella sonnei. Moreover, the interactions of these differential OTUs were sexually distinct. These findings demonstrated that the intestine of male and female mice preferred to accommodate microbiota differently. Therefore, it is necessary to designate the gender of gnotobiotic mice for complete evaluation of modulatory effects of gut microbiota from human feces upon diseases.

Digestibility and prebiotic properties of potato rhamnogalacturonan I polysaccharide and its galactose-rich oligosaccharides/oligomers.

Galactose-rich oligosaccharides/oligomers (oligo-RG I) were produced by the enzymatic treatment of potato galactan-rich rhamnogalacturonan I (RG I) with endo-ß-1,4-galactanase and Depol 670L multi-enzymatic preparation. The digestibility study revealed that 81.6 and 79.3% of RG I and its corresponding oligomers remained unhydrolyzed, respectively. The prebiotic properties of RG I and its hydrolysates were investigated using a continuous culture system inoculated with immobilized fecal microbiota. Both RG I and oligo-RG I have stimulated the growth of Bifidobacterium spp. and Lactobacillus spp., with oligo-RG I hydrolysates being more selectively fermented by these beneficial bacteria. Furthermore, none of RG I nor its hydrolysates increased the populations of Bacteroidetes and Clostridium leptum. Total amounts of short chain fatty acids, generated upon the fermentation of oligo-RG I, were higher than those obtained with its parent RG I and the positive control (fructooligosaccharides). The overall study contributes to the understandings of the prebiotic properties of potato RG I and its corresponding oligosaccharides/oligomers.

A diagnosis of the microbiological quality of dehydrated bee-pollen produced in Brazil.

UNLABELLED: Bee-pollen is an apicultural product with potential for medical and nutritional applications; therefore, its microbiology quality should be monitored. In this context, the objective of this study was to diagnose the microbiological quality of 45 dehydrated bee-pollen samples collected from November 2011 to December 2013 in nine Brazilian States. All the samples were negative for sulphite-reducing Clostridium spores, Salmonella, coagulase-positive Staphylococcus and Escherichia coli, which are micro-organisms of public health concern. Total aerobic mesophilic micro-organism counts ranged from <10 to 1·10 × 10(4) CFU g(-1) , with psychrotroph counts ranging from <10 to 1·12 × 10(3) CFU g(-1) and total coliforms from <10 to 2·80 × 10(3) CFU g(-1) , while the values for yeasts and moulds were between <10 to 7·67 × 10(3) CFU g(-1) . According to the literature, the microbiota observed in this study were typical; however, it is important to consider that these micro-organisms may cause spoilage and diminish shelf life, reason by which quality control programs should be implemented. SIGNIFICANCE AND IMPACT OF THE STUDY: Contamination of bee-pollen can occur during production, collection and processing, but there are few studies of the microbiological quality of this product. Brazil is an important producer of dehydrated bee-pollen, therefore, a diagnosis of the microbiological status is important to ensure the safety of many consumers. Salmonella sp., genus Clostridium, coagulase-positive Staphylococcus, Escherichia coli and even some yeast species are micro-organisms of public health concern and their presence must be monitored. Furthermore, the determination of spoilage micro-organisms indicates whether the production and the processing practices carried out by beekeepers and warehouses were adequate.

In vitro fermentation of lupin seeds (Lupinus albus) and broad beans (Vicia faba): dynamic modulation of the intestinal microbiota and metabolomic output.

Broad beans (Vicia faba) and lupin seeds (Lupinus albus) are legumes rich in a wide range of compounds, which may represent a useful dietary approach for modulating the human gut microbiome. In this work, after in vitro digestion, legume samples were used as carbon sources in anaerobic batch cultures to evaluate their impact on the intestinal microbiota composition and on their metabolic products. The fermentations were monitored by a decrease in pH, generation of short chain fatty acids (SCFA) and lactate and the changes in the dynamic bacterial populations by fluorescence in situ hybridization (FISH). The total SCFA at the end of fermentation was 81.52 mM for lupin seeds and 78.41 mM for broad beans accompanied by a decrease of the pH for both legumes. The microbial groups that increased significantly (P < 0.05) were Bifidobacterium spp., Lactobacillus-Enterococcus, Atopobium, Bacteroides-Pretovella, Clostridium coccoides-Eubacterium rectale, Faecalibacterium prausnitzii and Roseburia intestinalis. This impact on the intestinal microbiota suggests that lupin seeds and broad beans may be used in the development of novel functional foods, which can be included in dietary strategies for human health promotion.

Butyric acid production from red algae by a newly isolated Clostridium sp. S1.

OBJECTIVE: To produce butyric acid from red algae such as Gelidium amansii in which galactose is a main carbohydrate, microorganisms utilizing galactose and tolerating inhibitors in hydrolysis including levulinic acid and 5-hydroxymethylfurfural (HMF) are required. RESULTS: A newly isolated bacterium, Clostridium sp. S1 produced butyric acid not only from galactose as the sole carbon source but also from a mixture of galactose and glucose through simultaneous utilization. Notably, Clostridium sp. S1 produced butyric acid and a small amount of acetic acid with the butyrate:acetate ratio of 45.4:1 and it even converted acetate to butyric acid. Clostridium sp. S1 tolerated 0.5-2 g levulinic acid/l and recovered from HMF inhibition at 0.6-2.5 g/l, resulting in 85-92% butyric acid concentration of the control culture. When acid-pretreated G. amansii hydrolysate was used, Clostridium sp. S1 produced 4.83 g butyric acid/l from 10 g galactose/l and 1 g glucose/l. CONCLUSION: Clostridium sp. S1 produces butyric acid from red algae due to its characteristics in sugar utilization and tolerance to inhibitors, demonstrating its advantage as a red algae-utilizing microorganism.

Chemically defined diet alters the protective properties of fructo-oligosaccharides and isomalto-oligosaccharides in HLA-B27 transgenic rats.

Non-digestible oligosaccharides (NDO) were shown to reduce inflammation in experimental colitis, but it remains unclear whether microbiota changes mediate their colitis-modulating effects. This study assessed intestinal microbiota and intestinal inflammation after feeding chemically defined AIN-76A or rat chow diets, with or without supplementation with 8 g/kg body weight of fructo-oligosaccharides (FOS) or isomalto-oligosaccharides (IMO). The study used HLA-B27 transgenic rats, a validated model of inflammatory bowel disease (IBD), in a factorial design with 6 treatment groups. Intestinal inflammation and intestinal microbiota were analysed after 12 weeks of treatment. FOS and IMO reduced colitis in animals fed rat chow, but exhibited no anti-inflammatory effect when added to AIN-76A diets. Both NDO induced specific but divergent microbiota changes. Bifidobacteria and Enterobacteriaceae were stimulated by FOS, whereas copy numbers of Clostridium cluster IV were decreased. In addition, higher concentrations of total short-chain fatty acids (SCFA) were observed in cecal contents of rats on rat chow compared to the chemically defined diet. AIN-76A increased the relative proportions of propionate, iso-butyrate, valerate and iso-valerate irrespective of the oligosaccharide treatment. The SCFA composition, particularly the relative concentration of iso-butyrate, valerate and iso-valerate, was associated (P ≤ 0.004 and r ≥ 0.4) with increased colitis and IL-1 ß concentration of the cecal mucosa. This study demonstrated that the protective effects of fibres on colitis development depend on the diet. Although diets modified specific cecal microbiota, our study indicates that these changes were not associated with colitis reduction. Intestinal inflammation was positively correlated to protein fermentation and negatively correlated with carbohydrate fermentation in the large intestine.

Effect of dietary supplementation of (-)-epigallocatechin gallate on gut microbiota and biomarkers of colonic fermentation in rats.

Alterations in gut microbiota composition offer insights that may be relevant for several chronic conditions, including obesity. This study aimed to evaluate the effect of (-)-epigallocatechin gallate (EGCG) on the modulation of gut microbiota and biomarkers of colonic fermentation end-products in rats. Rats were fed an assigned diet of either a control diet, a 0.3% (w/w) EGCG diet, or a 0.6% (w/w) EGCG diet for 4 wk. Compared to the control group, the addition of 0.6% EGCG to the diet brought about a significant increase in the starch and protein contents in the feces collected in the fourth week of feeding, but the relative weights of abdominal adipose tissues of rats were inversely suppressed. Host-specific bacterial community composition, as determined by terminal restriction fragment length polymorphism (T-RFLP) patterns for fecal 16S ribosomal RNA, showed a significant response in the reduced occupation of Clostridium spp. and an increased trend of Bacteroides by dietary supplementation with EGCG. The 0.6% EGCG diet also influenced the status of Bifidobacterium and Prevotella to a lesser extent. Interestingly, the cecum of rats fed the 0.6% EGCG diet contained lower levels of acetic and butyric acids, whereas EGCG had little influence on the cecal level of propionic acid. EGCG also reduced the cecal p-cresol concentration in a dose-dependent fashion. In conclusion, dietary EGCG affects the growth of certain species of gut microbiota in rats and is associated with the cecal pattern of short chain fatty acids which could be responsible for regulating energy metabolism in the body.

Uranium removal and microbial community in a H2-based membrane biofilm reactor.

We evaluated a hydrogen-based membrane biofilm reactor (MBfR) for its capacity to reduce and remove hexavalent uranium [U(VI)] from water. After a startup period that allowed slow-growing U(VI) reducers to form biofilms, the MBfR successfully achieved and maintained 94-95% U(VI) removal over 8 months when the U surface loading was 6-11 e(-) mEq/m(2)-day. The MBfR biofilm was capable of self-recovery after a disturbance due to oxygen exposure. Nanocrystalline UO2 aggregates and amorphous U precipitates were associated with vegetative cells and apparently mature spores that accumulated in the biofilm matrix. Despite inoculation with a concentrated suspension of Desulfovibrio vulgaris, this bacterium was not present in the U(VI)-reducing biofilm. Instead, the most abundant group in the biofilm community contained U(VI) reducers in the Rhodocyclaceae family when U(VI) was the only electron acceptor. When sulfate was present, the community dramatically shifted to the Clostridiaceae family, which included spores that were potentially involved in U(VI) reduction.

Korean ginseng modulates the ileal microbiota and mucin gene expression in the growing rat.

The study was conducted to investigate whether oral administration of Korean ginseng powders can modulate gut microbiota as well as intestinal mucin production at the translational and transcriptional levels in the ileum of the growing rat. Thirty individually caged Sprague-Dawley male rats were allocated to three groups (n = 10) and fed for 21 days either a basal control diet or one of the two treatment diets each containing white or red Korean ginseng (WG or RG) powder. Bacterial DNA was extracted from ileal digesta and subjected to quantitative real-time PCR (qPCR) using primers for total bacteria, Lactobacillus, Bifidobacteria, Escherichia coli, Bacteroides, and Clostridium strains. The qPCR results showed that consumption of WG or RG powder significantly increased the number of total bacteria and Lactobacillus strains compared to the control group. Consumption of WG powder increased mRNA expression of the Muc2 gene in the small intestine compared to the control group. There was no effect of WG or RG on the small intestinal digesta mucin content. Correlation analysis showed that expression of the Muc2 gene was significantly associated with the number of total bacteria (r = 0.52, P < 0.05) and Lactobacillus strains (r = 0.53, P < 0.05), respectively. Furthermore, the number of Lactobacillus strains was significantly correlated with the number of total bacteria (r = 0.87, P < 0.05). Consumption of the WG powder modulated the intestinal ecosystem of the growing rat and intestinal mucin gene expression.

Clostridium bornimense sp. nov., isolated from a mesophilic, two-phase, laboratory-scale biogas reactor.

A novel anaerobic, mesophilic, hydrogen-producing bacterium, designated strain M2/40(T), was isolated from a mesophilic, two-phase, laboratory-scale biogas reactor fed continuously with maize silage supplemented with 5% wheat straw. 16S rRNA gene sequence comparison revealed an affiliation to the genus Clostridium sensu stricto (cluster I of the clostridia), with Clostridium cellulovorans as the closest characterized species, showing 93.8% sequence similarity to the type strain. Cells of strain M2/40(T) were rods to elongated filamentous rods that showed variable Gram staining. Optimal growth occurred at 35 °C and at pH 7. Grown on glucose, the main fermentation products were H2, CO2, formate, lactate and propionate. The DNA G+C content was 29.6 mol%. The major fatty acids (>10 %) were C(16 : 0), summed feature 10 (C(18 : 1)ω11c/ω9t/ω6t and/or unknown ECL 17.834) and C(18 : 1)ω11c dimethylacetal. Based on phenotypic, chemotaxonomic and phylogenetic differences, strain M2/40(T) represents a novel species within the genus Clostridium, for which we propose the name Clostridium bornimense sp. nov. The type strain is M2/40(T) ( = DSM 25664(T) = CECT 8097(T)).