Survival and stress induced expression of groEL and rpoD of Campylobacter jejuni from different growth phases.
Although Campylobacter jejuni is the leading cause of bacterial diarrhoeal disease in humans worldwide, its potential to adapt to the stressful conditions and survive in extra-intestinal environment is still poorly understood. We tested the effect of heat shock (55 degrees C, 3 min) and oxidative stress (3 mM H2O2 for 10 min or prolonged incubation at atmosphere oxygen concentration) on non-starved and starved cells of Campylobacter jejuni from different growth phases. Viability as assessed with the Bacterial Viability Kit LIVE/DEAD BacLighttrade mark dying before fluorescent microscopy and culturability of the cells (CFU ml(-1)) from both growth phases showed that starvation increased heat but not oxidative resistance. High temperature and oxidative stress invoked quick transformation from culturable spiral shaped to nonculturable spiral and coccoid cells. Despite physiological changes of the cells we were not able to document clear differences in the expression of heat shock and starvation genes (dnaK, htpG, groEL), oxidative (ahpC, sodB), virulence (flaA) and housekeeping genes (16S rRNA, rpoD) after heat treatment (55 degrees C, 3 min) or oxidative stresses applied. When starving, no induction of expression of any of these genes was noticed, chloramphenicol had no influence on their gene expression. Quantitative real-time PCR analyses showed that at least 10-20 min of heat shock was necessary to evidently increase the amount of groEL and rpoD transcripts.
Klancnik
Anja
A
University of Ljubljana, Biotechnical Faculty, Department of Food Science and Technology, Jamnikarjeva 101, SI-1111 Ljubljana, Slovenia.
Botteldoorn
Nadine
N
Herman
Lieve
L
Mozina
Sonja Smole
SS
D000222:Adaptation, Physiological; D016123:Campylobacter jejuni / Q000235:genetics* / Q000254:growth & development* / Q000302:isolation & purification; D018834:Chaperonin 60; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005453:Fluorescence; D005516:Food Microbiology; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D006358:Hot Temperature; D050296:Microbial Viability; D018384:Oxidative Stress / Q000187:drug effects; D010100:Oxygen / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D018834:Chaperonin 60; D012329:RNA, Bacterial; D010100:Oxygen