Estado viável não cultivável em Salmonella enterica sorovar Enteritidis deficiente na síntese de (p)ppGpp

• Autor(a) principal: Rodrigues, Ramila Cristiane
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5356
• topic: Salmonella enterica; Estado viável não cultivável; (p)ppGpp; Salmonella enterica; Viable state uncultivable, (p)ppGpp; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::MICROBIOLOGIA AGRICOLA

Salmonella enterica is a foodborne pathogen able to enter in viable but nonculturable state (VNC) in response to adverse environmental conditions. S. enterica is capable to produce (p)ppGpp, a nucleotide responsible for controlling gene expression at the level of transcription and translation in nutritional stress conditions. Due to gene expression determined by the accumulation of (p)ppGpp, S. enterica supports various environmental conditions. The aims of this work were to quantify by real time PCR the expression of the genes mreB, related to the cytoskeleton, and rpoS, which codifies stress response genes, in single and double mutants of Salmonella Enteritidis PT4 578 deficient in the synthesis of (p)ppGpp, due to the mutation on gene relA, which codifies a GTP pyrophosphokinase, and, or spoT, which codifies guanosine-3',5'-diphosphate 3'-pyrophosphohydrolase, submitted to nutritional stress and cold shock; to induce these strains to VNC state in Butterfield phosphate solution (BPS), in the absence or presence of sodium chloride at 4 ºC and to evaluate the morphology of these strains in logarithmic growth phase and in VNC state. The expression of gene mreB was reduced in both mutant strains (single and double) after 25 days in stress condition. However, the double mutant presented an increase in rpoS gene expression after 25 days in the same stress condition. Wild and mutant strains of Salmonella Enteritidis PT4 578 entered in VNC state after incubation in BPS in the absence or presence of sodium chloride at 4 °C, in different periods of time. Single and double mutant strains of Salmonella Enteritidis PT4 578 in logarithmic growth phase presented filamentous cells. On the other hand, VNC cells of single and double mutants showed a reduction in diameter, volume and length and also transition from bacillary to coccoid form. In conclusion, the expression of mreB and rpoS genes in single and double mutant strains of Salmonella Enteritidis PT4 578 was different when compared to the wild strain. There was also alteration in the morphology of cells in log phase when compared to the VNC cells of mutant strains of Salmonella Enteritidis PT4 578. However, the (p)ppGpp molecule is not essential for induction and permanence of this bacterium in VNC state.