Project description:Peripheral serotonin (5-hydroxytryptamine: 5-HT) synthesized in the intestine by enterochromaffin cells (ECs), plays an important role in the regulation of peristaltic of the gut, epithelial secretion and promotes the development and maintenance of the enteric neurons. Recent studies showed that the indigenous gut microbiota modulates 5-HT signalling and that ECs use sensory receptors to detect dietary and microbiota-derived signals from the lumen to subsequently transduce the information to the nervous system. We hypothesized that Clostridium ramosum by increasing gut 5-HT availability consequently contributes to high-fat diet-induced obesity. Using germ-free mice and mice monoassociated with C. ramosum, intestinal cell lines and mouse organoids, we demonstrated that bacterial cell components stimulate host 5-HT secretion and program the differentiation of colonic intestinal stem progenitors toward the secretory 5-HT-producing lineage. An elevated 5-HT level regulates the expression of major proteins involved in intestinal fatty acid absorption in vitro, suggesting that the presence of C. ramosum in the gut promotes 5-HT secretion and thereby could facilitates intestinal lipid absorption and the development of obesity.
Project description:Premise:A set of polymorphic nuclear microsatellite loci was developed and tested for use in population genetic analyses of Anthericum ramosum (Agavaceae) and related species. Methods and Results:Sequences of 110 primers were extracted in silico from Illumina MiSeq genome skimming data. The degree of polymorphism of 19 loci was tested in four A. ramosum populations collected in Central and Eastern Europe. The average number of alleles per loci ranged from two to 17, and levels of observed and expected heterozygosity ranged from 0.000 to 1.000 and from 0.100 to 0.900, respectively. Primers were successfully amplified in the closely related species A. liliago (12 loci) and Chlorophytum comosum (six loci), whereas they mostly failed to amplify in the phylogenetically more-distant species Muscari comosum (three loci) and M. tenuiflorum (no amplification). Conclusions:This newly developed set of polymorphic nuclear microsatellite markers will be useful for population genetic investigation of A. ramosum and closely related species.
Project description:UnlabelledThe intestines of obese humans and mice are enriched with Erysipelotrichi, a class within the Firmicutes. Clostridium ramosum, a member of the Erysipelotrichi, is associated with symptoms of the metabolic syndrome in humans. To clarify the possible obesogenic potential of this bacterial species and to unravel the underlying mechanism, we investigated the role of C. ramosum in obesity development in gnotobiotic mice. Mice were associated with a simplified human intestinal (SIHUMI) microbiota of eight bacterial species, including C. ramosum, with the SIHUMI microbiota except C. ramosum (SIHUMIw/oCra), or with C. ramosum only (Cra) and fed a high-fat diet (HFD) or a low-fat diet (LFD). Parameters related to the development of obesity and metabolic diseases were compared. After 4 weeks of HFD feeding, the mouse groups did not differ in energy intake, diet digestibility, gut permeability, and parameters of low-grade inflammation. However, SIHUMI and Cra mice fed the HFD gained significantly more body weight and body fat and displayed higher food efficiency than SIHUMIw/oCra mice fed the HFD. Gene expression of glucose transporter 2 (Glut2) in jejunal mucosa and of fatty acid translocase (CD36) in ileal mucosa was significantly increased in the obese SIHUMI and Cra mice compared with the less obese SIHUMIw/oCra mice. The data demonstrate that the presence of C. ramosum in SIHUMI and Cra mice enhanced diet-induced obesity. Upregulation of small intestinal glucose and fat transporters in these animals may contribute to their increased body fat deposition.ImportanceObesity is a growing health problem worldwide. Changes in the proportions of Bacteroidetes and Firmicutes, the two dominant phyla in the human and the murine intestinal tract, link the intestinal microbiota to obesity. Erysipelotrichi, a class within the Firmicutes, increase in response to high-fat feeding in mice. Clostridium ramosum, a member of the Erysipelotrichi, has been linked to symptoms of the metabolic syndrome. We hypothesized that C. ramosum promotes obesity development and related pathologies. Our experiments in gnotobiotic mice show that C. ramosum promoted diet-induced obesity, probably by enhancing nutrient absorption. Identification of obesogenic bacteria and understanding their mode of action enable the development of novel strategies for the treatment of this epidemic disease. Pharmaceuticals that target obesogenic bacteria or their metabolism could help to prevent and treat obesity and related disorders in the future.
Project description:Clostridium ramosum is an enteric anaerobic, endospore-forming, gram-positive rod with a low GC content that is rarely associated with disease in humans. We present a case of C. ramosum bacteraemia. To the best of our knowledge, this is the second case of C. ramosum bacteraemia in an elderly patient presenting with fever, abdominal pain and bilious emesis. We highlight the Gram stain variability, the lack of visualization of spores and the atypical morphology of the colonies that showed C. ramosum in a polymicrobial presentation that initially appeared to show monomicrobial bacteraemia. The microorganism was rapidly identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We present a comprehensive literature review of 32 cases of clinical infections by C. ramosum in which we describe, if available, sex, age, clinical symptoms, predisposing conditions, other organisms present in the blood culture, other samples with C. ramosum , identification methodology, treatment and outcome.