Biomedical subjects

Alain L Servin

Publications and source records attributed to Alain L Servin.

21 records · Page 2Linked to original sources

PubMed2003

Adhesion of probiotic strains to the intestinal mucosa and interaction with pathogens.

Probiotic lactic acid strains are live micro-organisms that, when consumed in adequate amounts as part of food, confer a health benefit on the host. The scientific basis for the use of selected probiotic strains has only recently been firmly established, and appropriate and well-conducted experimental in vitro and in vivo studies, as well as clinical studies, are now beginning to be published, especially with regard to the effectiveness of probiotic strains in antagonizing pathogens. In particular, experimental data have allowed new insights into selected probiotic strains that express strain-specific probiotic properties and into the mechanism of action of these strains. The objective of this review is to analyse the in vitro or in vivo experimental studies in which the antimicrobial activity of selected Lactobacillus and Bifidobacterium strains has been documented.

Animals↗

PubMed2002

Activation of mucin exocytosis and upregulation of MUC genes in polarized human intestinal mucin-secreting cells by the thiol-activated exotoxin listeriolysin O.

The secreted thiol-activated cytolysin listeriolysin O (LLO) was responsible for L. monocytogenes-induced high-molecular glycoproteins (HMGs) exocytosis in cultured human mucosecreting HT29-MTX cells. By biochemical analysis we demonstrate that the majority of secreted HMGs in LLO-stimulated cells are of mucin origin. In parallel, analysis of the expression of MUCs genes showed that the transcription of the MUC3, MUC4 and MUC12 genes encoding for membrane-bound mucins was increased in LLO-stimulated cells. Upregulation of the MUC3 gene correlates with an increased expression of the membrane-bound MUC3 mucin. In contrast, increase in secretion of the gel-forming MUC5AC mucin develops without upregulation of the MUC5AC gene. Finally, results showed that NF-kappaB and AP-1 transcription factors were not involved in LLO-induced upregulation of MUCs genes in HT29-MTX cells, whereas L. monocytogenes infection was able to promote the degradation of IkappaB proteins in the cells.

Bacterial Proteins↗

PubMed2002

Representational difference analysis between Afa/Dr diffusely adhering Escherichia coli and nonpathogenic E. coli K-12.

Diffusely adhering Escherichia coli strains harboring Afa/Dr adhesins (Afa/Dr DAEC) have been associated with diarrhea and urinary tract infections (UTIs). The present work is the first extensive molecular study of a Afa/Dr DAEC strain using the representational difference analysis technique. We have searched for DNA sequences present in strain C1845, recovered from a diarrheagenic child, but absent from a nonpathogenic K-12 strain. Strain C1845 harbors part of a pathogenicity island (PAI(CFT073)) and several iron transport systems found in other E. coli pathovars. We did not find genes encoding factors known to subvert host cell proteins, such as type III secretion system or effector proteins. Several C1845-specific sequences are homologous to putative virulence genes or show no homology with known sequences, and we have analyzed their distribution among Afa/Dr and non-Afa/Dr clinical isolates and among strains from the E. coli Reference Collection. Three C1845-specific sequences (MO30, S109, and S111) have a high prevalence (77 to 80%) among Afa/Dr strains and a low prevalence (12 to 23%) among non-Afa/Dr strains. In addition, our results indicate that strain IH11128, an Afa/Dr DAEC strain recovered from a patient with a UTI, is genetically closely related to strain C1845.

Adhesins, Bacterial↗