Delta A₆₀₀ 24 h after inoculation of reconstituted MRS media containing 2.0% glucose (white) or 0.3% HGM (gray) and residual growth of LAB in MRS with no fermentable carbohydrate.

<p>Asterisks indicate sequenced strains of LAB, circles commercial probiotic strains, and squares the strains selected for transcript analysis.</p

Copy number of mRNA/bacteria of binding related genes in <i>L. paraplantarum</i> 4.4 incubated with HT29 (diagonal hatched bar) or HT29-MTX (vertical hatched bar) and in <i>L. plantarum</i> WCFS1 incubated with HT29 (white) or HT29 MTX (black).

<p>Copy number of mRNA/bacteria of binding related genes in <i>L. paraplantarum</i> 4.4 incubated with HT29 (diagonal hatched bar) or HT29-MTX (vertical hatched bar) and in <i>L. plantarum</i> WCFS1 incubated with HT29 (white) or HT29 MTX (black).</p

Primers used to detect the presence or to measure the expression of LAB genes involved in binding ability.

<p>ND: primer pairs were not used for the qPCR assay.</p

Expression of bacterial binding related genes in the bulk of LAB present in the gnotobiotic rats caecum two days (BSL-2d) and 30 days (BSL-30d) after the inoculation with a mix of three lactobacilli (BSL).

<p>Asterisk indicates a significant difference between BSL-2d and BSL-30 d groups (p<0.05, Student-Newman-Keuls test). The transcript copy number in BSL-2d is in white. The transcript copy number in BSL-30d is in gray.</p

Densitometric analysis of autoradiography for amount of PCNA and p27Kip1 protein in colic epithelium in GF, BSL-2d, BSL-30d and CV rats (A) and number of PCNA and KI67 positive cells (B).

<p>Westernblot of PCNA (on the top) and p27Kip1 (on the bottom) proteins in colic epithelium in GF, BSL-2d, BSL-30d and CV rats (C). For PCNA and p27^Kip1 quantification, cullin proteins were used as internal controls. Ki67-positive cells and PCNA- positive cells are expressed as a percentage of total colonic crypt cells. Results are presented as means ± SE for n = 4 rats per group. Statistically significant differences (P<0.05, Student-Newman-Keuls test) between groups are indicated by different letters.</p

Relative expression of mucin related genes in the colon of GF, BSL-2d and BSL-30d rats compared to GAPDH expression from the conventionalized group.

<p>The relative expression of mucin related in GF is in white, in BSL-2d is in gray, and in BSL-30d is in black. Asterisk indicates a statistical difference between GF and BSL rats.</p

Percentage of AB and PAS stained cells to total cells.

<p>Percentage of AB and PAS stained cells to total cells.</p

Enumeration of LAB species present two days (BSL-2d) and 30 days (BSL-30d) after the inoculation with a mix of three lactobacilli (BSL)as measured by real time PCR based on the transcripts of the 16S rRNA gene extracted from caecum of the gnotobiotic rats.

<p>Different letters indicate a statistical difference (p<0.05, Student-Newman-Keuls test). The number of 16S rRNA gene copies per gram of caecum in BSL-2d is in white. The number of 16S rRNA gene copies per gram of caecum in BSL-30d is in gray.</p

Data_Sheet_1_Lacticaseibacillus casei CNCM I-5663 supplementation maintained muscle mass in a model of frail rodents.DOCX

The aim of this study was to identify a probiotic-based strategy for maintaining muscle anabolism in the elderly. In previous research, we found that individuals experiencing short bowel syndrome (SBS) after an intestinal resection displayed beneficial metabolic adjustments that were mediated by their gut microbes. Thus, these bacteria could potentially be used to elicit similar positive effects in elderly people, who often have low food intake and thus develop sarcopenia. Gut bacterial strains from an SBS patient were evaluated for their ability to (1) maintain Caenorhabditis elegans survival and muscle structure and (2) promote protein anabolism in a model of frail rodents (18-month-old rats on a food-restricted diet: 75% of ad libitum consumption). We screened a first set of bacteria in C. elegans and selected two Lacticaseibacillus casei strains (62 and 63) for further testing in the rat model. We had four experimental groups: control rats on an ad libitum diet (AL); non-supplemented rats on the food-restricted diet (R); and two sets of food-restricted rats that received a daily supplement of one of the strains (∼109 CFU; R+62 and R+63). We measured lean mass, protein metabolism, insulin resistance, cecal short-chain fatty acids (SCFAs), and SCFA receptor expression in the gut. Food restriction led to decreased muscle mass [−10% vs. AL (p 0.1)]. The mechanism appeared to be the stimulation of the insulin-sensitive p-S6/S6 and p-eIF2α/eIF2α ratios, which were similar in the R+63 and AL groups (p > 0.1) but lower in the R group (p < 0.05). We hypothesize that greater SCFA receptor sensitivity in the R+63 group promoted gut-muscle cross talk [GPR41: +40% and GPR43: +47% vs. R (p < 0.05)]. Hence, strain 63 could be used in association with other nutritional strategies and exercise regimes to limit sarcopenia in frail elderly people.</p

Image_1_Characterization of Mucus-Related Properties of Streptococcus thermophilus: From Adhesion to Induction.JPEG

<p>Mucus is a major component of the intestinal barrier involved both in the protection of the host and the fitness of commensals of the gut. Streptococcus thermophilus is consumed world-wide in fermented dairy products and is also recognized as a probiotic, as its consumption is associated with improved lactose digestion. We determined the overall effect of S. thermophilus on the mucus by evaluating its ability to adhere, degrade, modify, or induce the production of mucus and/or mucins. Adhesion was analyzed in vitro using two types of mucins (from pig or human biopsies) and mucus-producing intestinal HT29-MTX cells. The induction of mucus was characterized in two different rodent models, in which S. thermophilus is the unique bacterial species in the digestive tract or transited as a sub-dominant bacterium through a complex microbiota. S. thermophilus LMD-9 and LMG18311 strains did not grow in sugars used to form mucins as the sole carbon source and displayed weak binding to mucus/mucins relative to the highly adhesive TIL448 Lactococcus lactis. The presence of S. thermophilus as the unique bacteria in the digestive tract of gnotobiotic rats led to accumulation of lactate and increased the number of Alcian-Blue positive goblet cells and the amount of the mucus-inducer KLF4 transcription factor. Lactate significantly increased KLF4 protein levels in HT29-MTX cells. Introduction of S. thermophilusvia transit as a sub-dominant bacterium (10³ CFU/g feces) in a complex endogenous microbiota resulted in a slight increase in lactate levels in the digestive tract, no induction of overall mucus production, and moderate induction of sulfated mucin production. We thus show that although S. thermophilus is a poor mucus-adhesive bacterium, it can promote mucus pathway at least in part by producing lactate in the digestive tract.</p