Dataset Information

Gene expression of commensal Lactobacillus johnsonii strain NCC533 during in vitro growth and in the murine gut.

ABSTRACT: Work with pathogens like Vibrio cholerae has shown major differences between genes expressed in bacteria grown in vitro and in vivo. To explore this subject for commensals, we investigated the transcription of the Lactobacillus johnsonii NCC533 genome during in vitro and in vivo growth using the microarray technology. During broth growth, 537, 626, and 277 of the 1,756 tested genes were expressed during exponential phase, "adaptation" (early stationary phase), and stationary phase, respectively. One hundred one, 150, and 33 genes, respectively, were specifically transcribed in these three phases. To explore the in vivo transcription program, we fed L. johnsonii containing a resistance plasmid to antibiotic-treated mice. After a 2-day washout phase, we determined the viable-cell counts of lactobacilli that were in the lumina and associated with the mucosae of different gut segments. While the cell counts showed a rather uniform distribution along the gut, we observed marked differences with respect to the expression of the Lactobacillus genome. The largest number of transcribed genes was in the stomach (n = 786); the next-largest numbers occurred in the cecum (n = 391) and the jejunum (n = 296), while only 26 Lactobacillus genes were transcribed in the colon. In vitro and in vivo transcription programs overlapped only partially. One hundred ninety-one of the transcripts from the lactobacilli in the stomach were not detected during in vitro growth; 202 and 213 genes, respectively, were transcribed under all in vitro and in vivo conditions; but the core transcriptome for all growth conditions comprised only 103 genes. Forty-four percent of the NCC533 genes were not detectably transcribed under any of the investigated conditions. Nontranscribed genes were clustered on the genome and enriched in the variable-genome part. Our data revealed not only major differences between in vitro- and in vivo-expressed genes in a Lactobacillus gut commensal organism but also marked changes in the expression of genes along the digestive tract.

SUBMITTER: Denou E

PROVIDER: S-EPMC2168692 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature

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Gene expression of commensal Lactobacillus johnsonii strain NCC533 during in vitro growth and in the murine gut.

Denou Emmanuel E Berger Bernard B Barretto Caroline C Panoff Jean-Michel JM Arigoni Fabrizio F Brüssow Harald H

Journal of bacteriology 20070907 22

Work with pathogens like Vibrio cholerae has shown major differences between genes expressed in bacteria grown in vitro and in vivo. To explore this subject for commensals, we investigated the transcription of the Lactobacillus johnsonii NCC533 genome during in vitro and in vivo growth using the microarray technology. During broth growth, 537, 626, and 277 of the 1,756 tested genes were expressed during exponential phase, "adaptation" (early stationary phase), and stationary phase, respectively. ...[more]

PMID: 17827285

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Project description:Work with pathogens like Vibrio cholerae has shown major differences between gene expression in bacteria grown in vitro and in vivo. To explore this subject for commensals, we investigated the transcription of the Lactobacillus johnsonii NCC533 genome during in vitro using the microarray technology. In broth growth, 537, 626 and 277 of the 1756 tested genes were expressed during exponential, “adaptation” (early stationary phase) and stationary phase, respectively. One hundred-one, 150 and 33 genes, respectively, were specifically transcribed in these three phases. Forty-four per cent of the NCC533 genome were not detectably transcribed under any of the investigated conditions. Non-transcribed genes were clustered on the genome and enriched in the variable genome part. For gene expression profiling experiments, cells were grown in a Sixfors fermentor system, composed of four individual 500 ml vessels (Infors, Bottmingen, Switzerland). Growth curves were performed at least in triplicate using the four separate fermentation vessels (fermentor 1 to 4), which were inoculated at 0.4% (v/v) with four individual overnight cultures in order to reach a starting optical density (OD600nm) of 0.05. Samples were taken at regular intervals from the four vessels to measure the OD600 nm and determine the CFU/ml until 36 h of fermentation. Aliquots of 15 ml (for early (T1-T2) and mid-exponential phases (T3-T4)) and 10 ml (for adaptation (T5), mid-stationary (T6) and late stationary phases (T7)) were centrifuged for 5 min at 10,000 x g at 4°C. Cell pellets were snap frozen in liquid nitrogen and stored at –80°C until further use.L. johnsonii NCC533 was grown in MRS broth supplemented with 2 % glucose as carbon source and 0.05% cysteine as redox buffer. For mRNA isolation L. johnsonii NCC533 cells were harvested from the broth culture several time points after inoculation (Fig. 1). In a total of 27 hybridization experiments. Genes were scored as expressed when their signal was detected in all hybridization experiments (with two technical replicates per slide) with mRNA preparations obtained from three independent growth experiments. Keywords: Growth phases of Lactobacillus johnsonii NCC533 in MRS

Project description:Giardia duodenalis (syn. G. lamblia, G. intestinalis) is the protozoan parasite responsible for giardiasis, the most common and widely spread intestinal parasitic disease worldwide, affecting both humans and animals. After cysts ingestion (through either contaminated food or water), Giardia excysts in the upper intestinal tract to release replicating trophozoites that are responsible for the production of symptoms. In the gut, Giardia cohabits with the host's microbiota, and several studies have revealed the importance of this gut ecosystem and/or some probiotic bacteria in providing protection against G. duodenalis infection through mechanisms that remain incompletely understood. Recent findings suggest that Bile-Salt-Hydrolase (BSH)-like activities from the probiotic strain of Lactobacillus johnsonii La1 may contribute to the anti-giardial activity displayed by this strain. Here, we cloned and expressed each of the three bsh genes present in the L. johnsonii La1 genome to study their enzymatic and biological properties. While BSH47 and BSH56 were expressed as recombinant active enzymes, no significant enzymatic activity was detected with BSH12. In vitro assays allowed determining the substrate specificities of both BSH47 and BSH56, which were different. Modeling of these BSHs indicated a strong conservation of their 3-D structures despite low conservation of their primary structures. Both recombinant enzymes were able to mediate anti-giardial biological activity against Giardia trophozoites in vitro. Moreover, BSH47 exerted significant anti-giardial effects when tested in a murine model of giardiasis. These results shed new light on the mechanism, whereby active BSH derived from the probiotic strain Lactobacillus johnsonii La1 may yield anti-giardial effects in vitro and in vivo. These findings pave the way toward novel approaches for the treatment of this widely spread but neglected infectious disease, both in human and in veterinary medicine.

Project description:Giardia lamblia is the most frequently identified protozoan cause of intestinal infection. Over 200 million people are estimated to have acute or chronic giardiasis, with infection rates approaching 90% in areas where Giardia is endemic. Despite its significance in global health, the mechanisms of pathogenesis associated with giardiasis remain unclear, as the parasite neither produces a known toxin nor induces a robust inflammatory response. Giardia colonization and proliferation in the small intestine of the host may, however, disrupt the ecological homeostasis of gastrointestinal commensal microbes and contribute to diarrheal disease associated with giardiasis. To evaluate the impact of Giardia infection on the host microbiota, we used culture-independent methods to quantify shifts in the diversity of commensal microbes throughout the gastrointestinal tract in mice infected with Giardia We discovered that Giardia's colonization of the small intestine causes a systemic dysbiosis of aerobic and anaerobic commensal bacteria. Specifically, Giardia colonization is typified by both expansions in aerobic Proteobacteria and decreases in anaerobic Firmicutes and Melainabacteria in the murine foregut and hindgut. Based on these shifts, we created a quantitative index of murine Giardia-induced microbial dysbiosis. This index increased at all gut regions during the duration of infection, including both the proximal small intestine and the colon. Giardiasis could be an ecological disease, and the observed dysbiosis may be mediated directly via the parasite's unique anaerobic fermentative metabolism or indirectly via parasite induction of gut inflammation. This systemic alteration of murine gut commensal diversity may be the cause or the consequence of inflammatory and metabolic changes throughout the gut. Shifts in the commensal microbiota may explain observed variations in giardiasis between hosts with respect to host pathology, degree of parasite colonization, infection initiation, and eventual clearance.

Dataset Information

Gene expression of commensal Lactobacillus johnsonii strain NCC533 during in vitro growth and in the murine gut.

Publications

Gene expression of commensal Lactobacillus johnsonii strain NCC533 during in vitro growth and in the murine gut.

Similar Datasets

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