A marketed fermented dairy product containing Bifidobacterium lactis CNCM I-2494 suppresses gut hypersensitivity and colonic barrier disruption induced by acute stress in rats.

Background:   Fermented milk (FM) containing Bifidobacterium lactis CNCM I-2494 and yogurt strains improves irritable bowel syndrome (IBS) symptoms in constipated IBS patients. In rats, stressful events exacerbate IBS symptoms and result in the alteration of gut sensitivity and permeability via epithelial cell cytoskeleton contraction. In a stress model, we aimed at evaluating the effect of B.

Clinical trial: the effects of a fermented milk product containing Bifidobacterium lactis DN-173 010 on abdominal distension and gastrointestinal transit in irritable bowel syndrome with constipation.

Background: A sensation of abdominal swelling (bloating) and actual increase in girth (distension) are troublesome features of irritable bowel syndrome (IBS), which is more common in patients with constipation, especially those with delayed transit.

Aim: To establish whether a fermented dairy product containing Bifidobacterium lactis DN-173 010 reduces distension in association with acceleration of gastrointestinal transit and improvement of symptoms in IBS with constipation.

Methods: A single centre, randomized, double-blind, controlled, parallel group study in which patients consumed the test product or control product for 4 weeks.

Survival of Bifidobacterium animalis DN-173 010 in the faecal microbiota after administration in lyophilised form or in fermented product - a randomised study in healthy adults.

The survival of Bifidobacterium animalis strain DN-173 010 was assessed after its ingestion in a fermented product or in a lyophilised form. Twelve healthy subjects were included in a randomised, open study with 2 parallel groups. The composition and activities of the faecal microbiota were monitored before (10-day baseline step), during (1-week product administration step) and after (10-day follow-up step) the ingestion of 1 of the 2 products.

Survival of yogurt bacteria in the human gut.

Whether Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus can be recovered after passage through the human gut was tested by feeding 20 healthy volunteers commercial yogurt. Yogurt bacteria were found in human feces, suggesting that they can survive transit in the gastrointestinal tract.

Differential activities of four Lactobacillus casei promoters during bacterial transit through the gastrointestinal tracts of human-microbiota-associated mice.

In a previous study using fusion of the deregulated lactose promoter lacTp* and reporter genes, we suggested that Lactobacillus casei could initiate de novo protein synthesis during intestinal transit. In order to confirm this finding and extend it to other promoters, we adopted a reverse transcriptase quantitative PCR (RT-QPCR) approach combined with a transcriptional fusion system consisting of luciferase genes under the control of four promoters (ccpA, dlt, ldh, and lacT*) from L. casei DN-114 001.

Initiation of protein synthesis by a labeled derivative of the Lactobacillus casei DN-114 001 strain during transit from the stomach to the cecum in mice harboring human microbiota.

Although studies on the survival of bacteria in the digestive tract have been reported in the literature, little data are available on the physiological adaptation of probiotics to the digestive environment. In previous work, a transcriptional fusion system (i.e.

Lactobacillus casei is able to survive and initiate protein synthesis during its transit in the digestive tract of human flora-associated mice.

Live Lactobacillus casei is present in fermented dairy products and has beneficial properties for human health. In the human digestive tract, the resident flora generally prevents the establishment of ingested lactic acid bacteria, the presence of which is therefore transient. The aim of this work was to determine if L.

Glucose metabolism and regulation of glycolysis in Lactococcus lactis strains with decreased lactate dehydrogenase activity.

The distribution of carbon flux at the pyruvate node was investigated in Lactococcus lactis under anaerobic conditions with mutant strains having decreased lactate dehydrogenase activity. Strains previously selected by random mutagenesis by H. Boumerdassi, C.

Transcriptional and translational regulation of alpha-acetolactate decarboxylase of Lactococcus lactis subsp. lactis.

The alpha-acetolactate decarboxylase (ALDC) gene, aldB, is the penultimate gene of the leu-ilv-ald operon, which encodes the three branched-chain amino acid (BCAA) biosynthesis genes in Lactococcus lactis. Its product plays a dual role in the cell: (i) it catalyzes the second step of the acetoin pathway, and (ii) it controls the pool of alpha-acetolactate during leucine and valine synthesis. It can be transcribed from the two promoters present upstream of the leu and ilv genes (P1 and P2) or independently under the control of its own promoter (P3).

Dual role of alpha-acetolactate decarboxylase in Lactococcus lactis subsp. lactis.

The alpha-acetolactate decarboxylase gene aldB is clustered with the genes for the branched-chain amino acids (BCAA) in Lactococcus lactis subsp. lactis. It can be transcribed with BCAA genes under isoleucine regulation or independently of BCAA synthesis under the control of its own promoter.