Cell wall modifications during osmotic stress in Lactobacillus casei

• Autores: Piuri, M.; Sanchez-Rivas, C.; Ruzal, S.M.
• Año de publicación: 2005
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: J. Appl. Microbiol. 2005;98(1):84-95
• Materia: Lactobacillus casei; Osmotic stress; PBP; Peptidoglycan; ampicillin; antibiotic agent; bacitracin; enzyme; fosfomycin; mutanolysin; nisin; penicillin binding protein; penicillin G; peptidoglycan; sodium chloride; unclassified drug; vancomycin; cytology; microbiology; osmoregulation; stress; analytic method; antibiotic sensitivity; article; bacterial cell; bacterial cell wall; cell growth; controlled study; cytolysis; in vivo study; lactic acid bacterium; Lactobacillus casei; lysis; nonhuman; osmolarity; osmotic stress; purification; sensitivity analysis; transmission electron microscopy; Bacteriological Techniques; Cell Wall; Drug Resistance; Electrophoresis, Polyacrylamide Gel; Hydrolysis; Lactobacillus casei; Microscopy, Electron; Osmosis; Penicillin-Binding Proteins; Peptidoglycan; Bacteria (microorganisms); Lactobacillus; Lactobacillus casei; Posibacteria
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

Aims: To study the modification of the cell wall of Lactobacillus casei ATCC 393 grown in high salt conditions. Methods and Results: Differences in the overall structure of cell wall between growth in high salt (MRS + 1 mol l -1 NaCl; N condition) and control (MRS; C condition) conditions were determined by transmission electronic microscopy and analytical procedures. Lactobacillus casei cells grown in N condition were significantly larger than cells grown under unstressed C condition. Increased sensitivity to mutanolysin and antibiotics with target in the cell wall was observed in N condition. Purified cell wall also showed the increased sensitivity to lysis by mutanolysin. Analysis of peptidoglycan (PG) from stressed cells showed that modification was at the structural level in accordance with a decreased PG cross-link involving penicillin-binding proteins (PBP). Nine PBP were first described in this species and these proteins were expressed in low percentages or presented a modified pattern of saturation with penicillin G (Pen G) during growth in high salt. Three of the essential PBP were fully saturated in N condition at lower Pen G concentrations than in C condition, suggesting differences in functionality in vivo. Conclusions: The results show that growth in high salt modified the structural properties of the cell wall. Significance and Impact of Study: Advances in understanding the adaptation to high osmolarity, in particular those involving sensitivity to lysis of lactic acid bacteria.
Fil:Piuri, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Ruzal, S.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.