ISOLATION AND CHARACTERIZATION OF AN ACYLLIPID DESATURASE MUTANT OF ATCC1457 Bacillus cereus

CHAZARRETA-CIFRE, LORENA; DE MENDOZA, D; ALTABE, SILVIA (AUTOR CORRESPONDIENTE)

Mendoza

Congreso; 48 th Reunion Anual de la Sociedad Argentina de Investigacion en Bioqímica y Biología Molecular; 2012

SAIB

B. cereus is an opportunistic pathogen that can induce food poisoning and has the ability to grow at temperatures between 4ºC and 50°C. These bacteria adapt membrane fluidity during low temperature growth by different mechanisms such as increasing the proportion of unsaturated fatty acids (UFAs) that are essential for the maintenance of membrane structure and function. In a previous work we described that ATCC14579 has two acyl lipid desaturases, BC0400 and BC2983 that are involved in the synthesis of UFAs with double bonds in 10 and 5 positions, respectively. When cells of growing at 37ºC are shifted to 20ºC only 5-UFAs are increased, indicating that adaptation of the membrane fluidity at lower temperatures might depend on BC2983 activity. In this work we report the construction and characterization of a mutant in 5-Des, LSC2983, by a simple and efficient method that uses a temperature-sensitive vector that carries a selectable marker. The impact of this mutation on FA composition analyzed by GC-MS showed that strain LSC2983 did not synthesize 5-UFAs. This mutant grows as wild type strain in minimal medium at low temperature showing that 5-UFAs synthesis is not essential for growth indicating that an additional mechanism is also involved in cold adaptation