Pluricellularity and adhesive properties of the anti-infective probiotic bacterium Bacillus subtilis natto

ROVETTO, A.; LOMBARDIA, E.; ROBERTO RICARDO GRAU

Viena

Congreso; 11th International Congress on Microbial Ecology, ISME 11; 2006

PLURICELLULARITY AND ADHESIVE PROPERTIES OF THE ANTI-INFECTIVE PROBIOTIC BACTERIUM BACILLUS SUBTILIS NATTO   Adrián J. Rovetto1, Ester D. Saball2, Marcela Salvarrey2, Tamara Spandling1, Esteban Lombardía1, and Roberto R. Grau1*   1,2 Facultad de Ciencias Bioquímicas y Farmacéuticas (FCByF), Universidad Nacional de Rosario (UNR) and 1 Instituto de Biología Molecular y Celular de Rosario, IBR-CONICET - Argentina For correspondence: E-mail: rovetto@ibr.gov.ar; robertograu@fulbrightweb.org / Tel. (54) 341-4353377 / Fax (54) 341-4804609.     Abstract: The ability to form robust biofilms, structured and specialized colonies, fruiting bodies, swarming and resistant spores are few examples of the plethora of developmental strategies that bacteria use in nature to survive. Bacillus subtilis is a spore former Gram positive bacterium and a model for the studies of bacterial social behavior and development. Here we report the social behavior, and its regulation, of the undomesticated and probiotic strain B. subtilis natto. We demonstrated that the three master developmental regulators Spo0A, AbrB and SinR are crucial for the expression of social behaviors in B. subtilis natto. Biofilm development and colony morphogenesis were under the positive and negative control of Spo0A and AbrB /SinR respectively. Swarming motility of the natto strain was under the positive control of Spo0A and to a lesser extent, under the positive control of AbrB and SinR. Single spo0A minus cells were completely unable to swarm, while single abrB and sinR mutants were partially defective in motility. Spectro-photometric and spectro-fluorimetric techniques demonstrated that the natto strain was able to adhere with high affinity and specificity to the extracellular matrix representative proteins fibronectin and collagen. Spo0A-proficient natto cells, but not Spo0A-deficient cells, were able to compete and to inhibit the adherence of pathogenic FITC-labelled Staphylococcus aureus cells to immobilized-fibronectin, a property that it would be of importance for the expression of the anti-infective properties of natto. These results are discussed and integrated in the physiological role that B. subtilis natto would has in the ecology of the gastrointestinal tract.