Lactocepin secreted by Lactobacillus exerts anti-inflammatory effects by selectively degrading proinflammatory chemokines.

The intestinal microbiota has been linked to inflammatory bowel diseases (IBD), and oral treatment with specific bacteria can ameliorate IBD. One bacterial mixture, VSL#3, containing Lactobacillus, Bifidobacterium, and Streptococcus, was clinically shown to reduce inflammation in IBD patients and normalize intestinal levels of IP-10, a lymphocyte-recruiting chemokine, in a murine colitis model. We identified Lactobacillus paracasei prtP-encoded lactocepin as a protease that selectively degrades secreted, cell-associated, and tissue-distributed IP-10, resulting in significantly reduced lymphocyte recruitment after intraperitoneal injection in an ileitis model.

Occurrence of the human tumor-specific antigen structure Galβ1-3GalNAcα- (Thomsen-Friedenreich) and related structures on gut bacteria: prevalence, immunochemical analysis and structural confirmation.

The Thomsen-Friedenreich antigen (TF; CD176, Galβ1-3GalNAcα-) is a tumor-specific carbohydrate antigen and a promising therapeutic target. Antibodies that react with this antigen are frequently found in the sera of healthy adults and are assumed to play a role in cancer immunosurveillance. In this study, we examined the occurrence of α-anomeric TF (TFα) on a large variety of gastrointestinal bacteria using a novel panel of well-characterized monoclonal antibodies.

Intraspecies genomic diversity and natural population structure of the meat-borne lactic acid bacterium Lactobacillus sakei.

Lactobacillus sakei is a food-borne bacterium naturally found in meat and fish products. A study was performed to examine the intraspecies diversity among 73 isolates sourced from laboratory collections in several different countries. Pulsed-field gel electrophoresis analysis demonstrated a 25% variation in genome size between isolates, ranging from 1,815 kb to 2,310 kb.

Clostridium asparagiforme sp. nov., isolated from a human faecal sample.

An obligatory anaerobic, Gram-positive, rod-shaped organism was isolated from faeces of a healthy human donor. It was characterized using biochemical, phenotypic and molecular taxonomic methods. The organism produced acetate, lactate, and ethanol as the major products of glucose fermentation.

Intestinal bacterial communities that produce active estrogen-like compounds enterodiol and enterolactone in humans.

Lignans are dietary diphenolic compounds which require activation by intestinal bacteria to exert possible beneficial health effects. The intestinal ecosystem plays a crucial role in lignan metabolism, but the organisms involved are poorly described. To characterize the bacterial communities responsible for secoisolariciresinol (SECO) activation, i.

Worst-case scenarios for horizontal gene transfer from Lactococcus lactis carrying heterologous genes to Enterococcus faecalis in the digestive tract of gnotobiotic mice.

Since genetically modified (GM) lactic acid bacteria (LAB) might be released in open environments for future nutritional and medical applications, the purpose of this study was to determine an upper limit for the horizontal gene transfer (HGT) in the digestive tract (DT) from Lactococcus lactis carrying heterologous genes (lux genes encoding a bacterial luciferase) to Enterococcus faecalis. Two enterococcal wide host-range conjugative model systems were used: (i) a system composed of a mobilizable plasmid containing the heterologous lux genes and a native conjugative helper plasmid; and (ii) a Tn916-lux transposon. Both systems were tested under the most transfer-prone conditions, i.

Characterization of a theta-type plasmid from Lactobacillus sakei: a potential basis for low-copy-number vectors in lactobacilli.

The complete nucleotide sequence of the 13-kb plasmid pRV500, isolated from Lactobacillus sakei RV332, was determined. Sequence analysis enabled the identification of genes coding for a putative type I restriction-modification system, two genes coding for putative recombinases of the integrase family, and a region likely involved in replication. The structural features of this region, comprising a putative ori segment containing 11- and 22-bp repeats and a repA gene coding for a putative initiator protein, indicated that pRV500 belongs to the pUCL287 subfamily of theta-type replicons.

Physical and genetic map of the Lactobacillus sakei 23K chromosome.

The Lactobacillus sakei 23K chromosome was analysed by pulsed-field gel electrophoresis after digestion with the restriction enzymes AscI, NotI and SfiI. The chromosome size was estimated to be 1845+/-80 kb. The use of I-CeuI, specific for rrn genes encoding 23S rRNAs, showed that seven rrn loci were present, on 40% of the chromosome.