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We engineered Lactobacillus paracasei to produce a dsRNA that would trigger RNAi-induced silencing of an essential gene in the nematode Caenorhabditis elegans. The dsRNA-expressing L. paracasei can be used in experiments conducted on culture plates and may also be used as an orally administrable dsRNA carrier for humans and other mammals., (Copyright (c) 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Lactobacillus equi sp. nov. is described on the basis of 18 strains isolated as one of the predominant intestinal lactobacilli from horse faecal specimens. These 18 strains were isolated from 10 horses of 6 different farms out of 20 horses of 10 farms examined. They were gram-positive, facultatively anaerobic, catalase-negative, non-spore-forming, non-motile, lactic-acid-homofermentative rods. The DNA G+C content was 38.9+/-0.8 mol %. DNA-DNA hybridization failed to associate these strains closely with any of the validly described type strains used. Analysis of the 16S rRNA gene sequence of representative strain YIT 0455T revealed that the new isolates represent a new Lactobacillus species, for which the name Lactobacillus equi is proposed. The type strain is YIT 0455T (= ATCC BAA-261T = JCM 10991T).

Colonization of the infant gut is believed to be critically important for a healthy growth as it influences gut maturation, metabolic, immune and brain development in early life. Understanding factors that influence this process is important, since an altered colonization has been associated with a higher risk of diseases later in life. Fecal samples were collected from 108 healthy neonates in the first half year of life. The composition and functionality of the microbiota was characterized by measuring 33 different bacterial taxa by qPCR/RT qPCR, and 8 bacterial metabolites. Information regarding gender, place and mode of birth, presence of siblings or pets; feeding pattern and antibiotic use was collected by using questionnaires. Regression analysis techniques were used to study associations between microbiota parameters and confounding factors over time. Bacterial DNA was detected in most meconium samples, suggesting bacterial exposure occurs in utero. After birth, colonization by species of Bifidobacterium, Lactobacillus and Bacteroides was influenced by mode of delivery, type of feeding and presence of siblings, with differences found at species level and over time. Interestingly, infant-type bifidobacterial species such as B. breve or B. longum subsp infantis were confirmed as early colonizers apparently independent of the factors studied here, while B. animalis subsp. lactis presence was found to be dependent solely on the type of feeding, indicating that it might not be a common infant gut inhabitant. One interesting and rather unexpected confounding factor was gender. This study contributes to our understanding of the composition of the microbiota in early life and the succession process and the evolution of the microbial community as a function of time and events occurring during the first 6 months of life. Our results provide new insights that could be taken into consideration when selecting nutritional supplementation strategies to support the developing infant gut microbiome. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of a fermented milk drink containing Lactobacillus casei Shirota (LcS) on the bowel habit (with emphasis on stool consistency) o f subjects suffering from hard stools. Secondly, it was tested whether the probiotic strain (LcS), was able to survive throughout the gastrointestinal tract. A double-blind, placebo-controlled, randomized study was carried out over an eight-week period in subjects with symptoms o f constipation (n=120). To all subjects, 65 ml/day of a probiotic fermented milk drink containing LcS or a placebo was administered. Patients completed a questionnaire to assess the consistency o f their stools. In half of the study population, the survival of the probiotic strain (LcS) was tested using (i) culture and (ii) an LcS specific monoclonal antibody to identify the cultured colonies as LcS (ELISA). There was a significant decrease in stool hardening when consuming a fermented milk drink containing LcS. The observed clinical effect went hand in hand with the observed microbiological effect as the number of viable LcS bacteria in the faeces increased when consuming fermented milk drink containing LcS and decreased during wash-out. [ABSTRACT FROM AUTHOR]

Abstract: We developed a novel selective medium, modified-rhamnose-2,3,5-triphenyltetrazolium chloride-LBS-vancomycin agar (M-RTLV agar), that utilizes the fermentability of l-rhamnose to distinguish Lactobacillus casei and Lactobacillus paracasei from Lactobacillus rhamnosus. Whereas L. casei and L. paracasei formed red colonies on the M-RTLV agar, L. rhamnosus formed either pink-toned colonies or white colonies with a red spot. An intervention study was conducted to confirm the capability of M-RTLV agar to detect ingested L. casei when recovered from human feces. Subjects consumed one bottle daily of a fermented milk product (Yakult® or Yakult® Light, which contains L. casei strain Shirota; LcS) for 7days. Diluents of the fecal samples were cultivated on M-RTLV agar. We were able to enumerate circular medium-sized red colonies, which were morphologically similar to L. casei/L. paracasei but clearly distinguishable from the remaining colonies owing to the color difference. These colonies were then subjected to enzyme-linked immunosorbent assay in order to identify the LcS. The viable counts of LcS were 6.6±0.7log10 CFU/g feces after intake of Yakult® and 6.5±0.6log10 CFU/g feces after intake of Yakult® Light (mean±SD). [Copyright &y& Elsevier]

Abstract: Probiotic bacteria are microorganisms that benefit the host through improvement of the balance of intestinal microflora and possibly by augmentation of host defense systems. We examined the mechanisms for the up-regulation of innate immune responses by a probiotic Lactobacillus casei ATCC27139, in vivo. Using mouse models of systemic Listeria monocytogenes infection and MethA fibrosarcoma tumorigenesis in combination with BALB/c and SCID mice, we found that parenteral administration of L. casei ATCC27139 confers a protective effect against L. monocytogenes infection and anti-tumor activity against MethA fibrosarcoma by activation of innate immunity, while L. casei ATCC27139-J1R strains, which are J1 phage-resistant strains that have been selected from MNNG-treated clones, lacked these activities. Substantial differences between ATCC27139 and ATCC27139-J1R strains were observed in the capacity to induce innate cytokines such as TNF-α, IL-12, IL-18, and IFN-γ, and pathogen-associated molecular pattern receptors, TLR2 and Nod2, by spleen cells. In addition, although phosphorylation of NF-κB p65 in spleen was equally enhanced in the ATCC27139- and the ATCC27139-J1R-treated groups, phosphorylation of both p38 MAPK and MAPKAPK-2 was significantly induced only by ATCC27139. Furthermore, inhibitors of NF-κB (sulfasalazine) and p38 MAPK (SB203580) significantly reduced cytokine production by the spleen cells of the mice treated with L. casei ATCC27139, suggesting that both NF-κB and p38 MAPK signaling pathways play important roles in the augmentation of innate immunity by the probiotic L. casei. [Copyright &y& Elsevier]

Lactobacillus crispatus YIT 12319 (LcY) was isolated from the oral cavity of a healthy subject as a new candidate probiotic with potential benefits for oral health. As a safety assessment of LcY, we performed an antibiotic susceptibility test and virulence-associated gene analysis using a draft genome sequence. Susceptibility to 15 antibiotics was analyzed according to the standard method of the International Dairy Federation/International Organization for Standardization, as recommended by the European Food Safety Authority. The results showed that the minimum inhibitory concentrations of LcY were not higher than those of other L. crispatus strains, which have not acquired resistance to any antibiotics, suggesting that LcY had no externally acquired transmissible antibiotic resistance genes. Analysis of virulence-associated genes using the draft genome of LcY found that there were fewer potential virulence-associated genes in LcY than in other probiotics. These findings suggest that LcY could be a candidate probiotic based on its safety profile. • L. crispatus YIT 12319 has not acquired strain-specific antibiotic resistance. • L. crispatus YIT 12319 was considered to be safe according to genome analysis. • L. crispatus YIT 12319 was considered to be safe based on EFSA guidelines. [ABSTRACT FROM AUTHOR]