IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
REGULATION OF UNSATURATED FATTY ACIDS BIOSYNTHESIS BY GROWTH TEMPERATURE IN Bacillus
Autor/es:
LORENA CHAZARRETA CIFRE; DIEGO DE MENDOZA; SILVIA ALTABE
Lugar:
Puerto Madryn
Reunión:
Congreso; XLVI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010
Institución organizadora:
Sociadad Argentina de Investigación Bioquímica y Biología Molecular
Resumen:
Bacilli cells respond to a decrease in growth temperature by introducing double bonds into fatty acids by desaturases enzymes. Our results show that B. cereus and B. licheniformis UFAs proportion in their membrane lipids increase as the growth temperature decrease. To analyze the desaturase expression upon a temperature shift we assayed the beta-galactosidase activity of des-lacZ fusions in cells of B. subtilis. When cultures grown at 37ºC were shifted to 25ºC the levels of beta-alactosidase increased for both D5-desaturases whereas the D10-desaturase of B. cereus showed a constitutively expression. Temperature response has been characterized in B. subtilis, where the D5-Des expression is tightly regulated by DesK-DesR regulatory system. The analysis of the genome of B. licheniformis and B. cereus reveals the existence of two genes encoding proteins that share a high level of identity with DesK and DesR only in B. licheniformis. We investigated the expression of des-lacZ fusions in strains of B. subtilis des-, desK-, desR-, and we found that the levels of beta-galactosidase activity at 25ºC of D5-Des of B. licheniformis was very low while the expression of the others Des-fusions were not affected. Our results indicate that D5-Des of B. licheniformis shares a common regulatory mechanism with B. subtilis but a different pathway controls UFAs biosynthesis in B. Cereus.