Lactobacillus casei BL23 Produces Microvesicles Carrying Proteins That Have Been Associated with Its Probiotic Effect.

A Paula Domínguez Rubio,Jimena H Martínez,Oscar E Pérez,Federico Coluccio Leskow,Mariana Piuri,Diana C Martínez Casillas

doi:10.3389/fmicb.2017.01783

Abstract

Archaea, bacteria, and eukarya secrete membrane microvesicles (MVs) as a mechanism for intercellular communication. We report the isolation and characterization of MVs from the probiotic strain Lactobacillus casei BL23. MVs were characterized using analytical high performance techniques, DLS, AFM and TEM. Similar to what has been described for other Gram-positive bacteria, MVs were on the nanometric size range (30–50 nm). MVs carried cytoplasmic components such as DNA, RNA and proteins. Using a proteomic approach (LC-MS), we identified a total of 103 proteins; 13 exclusively present in the MVs. The MVs content included cell envelope associated and secretory proteins, heat and cold shock proteins, several metabolic enzymes, proteases, structural components of the ribosome, membrane transporters, cell wall-associated hydrolases and phage related proteins. In particular, we identified proteins described as mediators of Lactobacillus’ probiotic effects such as p40, p75 and the product of LCABL_31160, annotated as an adhesion protein. The presence of these proteins suggests a role for the MVs in the bacteria-gastrointestinal cells interface. The expression and further encapsulation of proteins into MVs of GRAS (Generally Recognized as Safe) bacteria could represent a scientific novelty, with applications in food, nutraceuticals and clinical therapies.

Highlights

Functional foods benefit human health beyond their basic nutritional properties (Ferguson, 2009)
MVs from L. casei BL23 and B. subtilis 168, used as positive control, were isolated from liquid cultures according to the protocol described in Section “Materials and Methods” (Figure 1)
Concentrated supernatants from L. casei BL23 at 24 h produced a smaller MV pellet in comparison to 48 h, so for further characterization the MVs were collected at this later time point

Summary

Introduction

Functional foods benefit human health beyond their basic nutritional properties (Ferguson, 2009). They are consumed in a normal diet and contain biologically active components that can offer health benefits and reduce the risk of disease. Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the Lactobacillus casei BL23 Microvesicles Characterization host (Hill et al, 2014). They are included in cheese, yogurts and fermented milks, or available as dietary supplements in the form of a dehydrated product (Stanton et al, 2001)

Methods

Results

Conclusion