EVALUATION OF THE PROTEOLYTIC ACTIVITY OF DIFFERENT TYPE A BOTULINUM NEUROTOXINS OBTAINED FROM A MENDOZA (ARGENTINA) SOIL STRAIN AGAINST NEURAL TARGET PROTEINS

PATRICIA CABALLERO; TRONCOSO M; PAREJA V; FIGUEROA E; RA FERNANDEZ; PATTERSON SI; MIGUEL A. SOSA

San Luis

Congreso; XXXII Reunión Anual de la Sociedad de Biología de Cuyo; 2015

Sociedad de Biología de Cuyo

Botulinum neurotoxin (BNTx) type A, produced by Clostridium botulinum (Cb), is a prevalent serotype in strainsfrom Mendoza soils. Soil (Su) is the main reservoir for Cb, and is possibly one of the infectious sources for infantbotulism (IB). The high incidence of IB in breast-fed infants with no history of complementary feeding, raises thepossibility that soil is an important source of infection. In previous studies we found that cultured strains obtainedfrom Su and from IB cases differ in morphology and also in some BNTx biological properties. In this study weevaluated the proteolytic activity of the different BNTx against target proteins. Rat brain homogenates wereincubated with BNTx from either Su or IB and compared with that of the A-Hall strain, under controlled conditions.Proteolysis of SNAP-25 and synaptobrevin was analyzed by Western blot with specific monoclonal antibodies,detected by chemiluminescence. The quantitation of each protein was normalized to actin levels. We observed thatboth proteins are cleaved into smaller fragments by the Su toxin, and to a lesser extent than with the A-Hall.However, the IB toxin showed low activity against these synaptic proteins. The differential effect of the toxins isconsistent with the higher toxicity of Su compared to other strains. The differences between Su and IB toxins implya more powerful proteolysis-based toxic activity in the former. Interestingly, they could also indicate that thebacterium is highly modified during transit in the infant digestive tract.