INVESTIGATING THE ROLE OF N-ACETYLGLUCOSAMINE ON THE S-LAYER PROTEINS OF Lysinibacillus sphaericus.

JULIÁN TARSITANO; CARMEN SANCHEZ RIVAS; SANDRA RUZAL; MARÍA MERCEDES PALOMINO; JOAQUINA FINA MARTIN; PABLO WAEHNER; MARIANO PRADO ACOSTA; LUCÍA MALONE; MARIANA CLAUDIA ALLIEVI

Córdoba

Congreso; XI Congreso de Microbiología General SAMIGE; 2015

Lysinibacillus sphaericus is a spore forming gram positive bacteria whose vegetative cell surface is covered with S-layer proteins. This species is able to produce during the sporulation process, protein crystals associated to the spore wall with enthomopathogenic activity against mosquito larvae. L. sphaericus is unable to use sugars as carbon source other than N-acetylglucosamine (GlcNAc) for which a phosphoenolpyruvate (PEP) : sugar phosphotransferase system (PTS) is present. We have shown that S-layer proteins remain associated to the spores contributing not only to their ability of retaining metals (Allievi et al, 2011) but also acting as synergic agents in larvicidal activity against Aedes aegypti larvae, a known carrier of viruses causing Dengue and Chikungunya fevers, both diseases representing a global threat (Allievi et al, 2014). We have observed variations in the molecular masses of S-layer proteins produced in different growth stages in related strains. The role of glycosylation of Bacillus proteins in several strains? pathogenicity has been documented. Therefore, we have decided to study post translational modification on S-layer proteins on different strains and specifically the role of GlcNAc, as glycosil group donor of those modifications. The different strains used for these studies are ASB13052 and its isogenic mutant, bearing a deletion in the GlcNAc transport system (Δpts). The presence of S-layer proteins and a variation on the protein pattern depending on the growth phase of the bacteria and the strain used was verified by western blot. In addition it was also observed that the mutant had an altered sporulation process and therefore altered spore quality (heat resistance) as well as S-layer proteins of diverse molecular masses. Ongoing studies are focused on demonstrating whether these two characteristics are related to the different forms of S-layer observed and the role of N-acetylglucosamine on the larvicidal activity.