Lactic Acid Bacteria in Health and Disease

The genera, lactic acid bacteria (LAB) have been used by humans in production of fermented foods since time immemorial and in some ancient communities; consumption of LAB fermented foods products was  associated with improved health. Currently there is a keen scientific interest in developed countries on health benefits obtained due to consumption of fermented food products. LAB has been shown to ameliorate immune-mediated health complications such as allergy, atopic dermatitis, rhinitis, oral-tolerance, cancer and inflammatory bowl diseases. Studies have also shown that consumption of LAB fermented food products can lead to control of cardio-vascular diseases and improvement of mental health. Prevention of antibiotic associated diarrhoea, reduction in lactose intolerance, production of conjugated linoliec acid, breakdown of phytic (an inhibitor of mineral absorption in the intestine) acids and improvement of gut-microbial balance have also been linked with increased consumption of LAB fermented foods. Besides, the enormous benefits of consuming LAB fermented food products, there are very few studies conducted to determine the efficacy of traditionally fermented African food products. If conducted such studies may lead to prevention/control of several health complications, reduction in health costs and improved income and livelihoods of communities producing such foods

Dose-Dependent Immunomodulation of Human Dendritic Cells by the Probiotic Lactobacillus rhamnosus Lcr35

The response of the immune system to probiotics remains controversial. Some strains modulate the cytokine production of dendritic cells (DCs) in vitro and induce a regulatory response, while others induce conversely a pro-inflammatory response. These strain-dependent effects are thought to be linked to specific interactions between bacteria and pattern recognition receptors. We investigated the effects of a well characterized probiotic strain, Lactobacillus rhamnosus Lcr35, on human monocyte-derived immature DCs, using a wide range of bacterial concentrations (multiplicity of infection, MOI, from 0.01 to 100). DNA microarray and qRT-PCR analysis showed that the probiotic induced a large-scale change in gene expression (nearly 1,700 modulated genes, with 3-fold changes), but only with high doses (MOI, 100). The upregulated genes were mainly involved in immune response and identified a molecular signature of inflammation according to the model of Torri. Flow cytometry analysis also revealed a dose-dependent maturation of the DC membrane phenotype, until DCs reached a semi-mature state, with an upregulation of the membrane expression of CD86, CD83, HLA-DR and TLR4, associated with a down-regulation of DC-SIGN, MR and CD14. Measurement of the DC-secreted cytokines showed that Lcr35 induced a strong dose-dependent increase of the pro-Th1/Th17 cytokine levels (TNFα, IL-1β, IL-12p70, IL-12p40 and IL-23), but only a low increase in IL-10 concentration. The probiotic L. rhamnosus Lcr35 therefore induce a dose-dependent immunomodulation of human DCs leading, at high doses, to the semi-maturation of the cells and to a strong pro-inflammatory effect. These results contribute to a fuller understanding of the mechanism of action of this probiotic, and thus of its potential clinical indications in the treatment of either infectious or IgE-dependent allergic diseases

Genome sequence of Pichia kudriavzevii M12, a potential producer of bioethanol and phytase

A draft genome sequence of Pichia kudriavzevii M12 is presented here. The genome reveals the presence of genes encoding enzymes involved in xylose utilization and the pentose phosphate pathway for bioethanol production. Strain M12 is also a potential producer of phytases, enzymes useful in food processing and agriculture