. Study of parasporal inclusions by numerical análisis of their SDS-PAGE proteins.

ÁLVAREZ, ANALÍA; PERA, LICIA MARÍA; VIRLA, EDUARDO; BAIGORI, MARIO DOMINGO

Rosario. Santa Fe, Argentina.

Congreso; SAIB 42 th Annual Meeting.; 2006

SAIB

Study of parasporal inclusions by numerical analysis of their SDS-PAGE proteins profiles   Álvarez A, Pera LM; Virla E and Baigorí MD PROIMI. Belgrano y Pje. Caseros, 4000 Tucumán. Tel: 03814344888, e-mail: alvarez_analia@hotmail.com   Bacillus thuringiensis (Bt) is a Gram-positive, endospore-forming bacterium that produces proteinaceous parasporal inclusions during sporulation. These inclusions often contain δ-endotoxin proteins that cause rapid and fatal intoxication of several insect orders. It has been established that the inclusions proteins, encoded by cry genes, are highly heterogeneous in structures and biological activities. We previously reported a native Bt RT3 that shows a strong toxicity against Spodoptera frugiperda larvae. The aim of this work was to study parasporal inclusions by numerical analysis of their SDS-PAGE proteins profiles. Standard B. subtilis (1A571) and Bt strains (BGSC): 4A4, 4D3 and 4D1 as well as native strains were used throughout this study. Proteins were prepared by a rapid washing procedure. SDS-PAGE of standards and inclusions proteins was performed according to Laemmli method. Gels were stained with silver reagent and they were analyzed by using NTSYS program (SM coefficient and UPGMA). Two main groups of Bacillus strains can be differentiated showing a similarity of 90 % between them. Protein profiles from native strains were different from those of standard strains. Bt RT3 displays a similarity of 92% with Bt 4D1. This method was more sensitive to differentiate Bt strains than a set of biochemical tests. This work was supported by grants PICTO 761 and PIP 6062