Bioluminescence as a real-time monitor of injury and recovery in Salmonella typhimurium

Ellison, Annette; Perry, Stephen F.; Stewart, Gordon S. A. B.

doi:10.1016/0168-1605(91)90146-g

Cited by 31 publications

(17 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Before generating alternate explanations, it was important to establish whether the effect of competitors on Salmonella was uniquely associated with heat as an inimical process. Freeze-thaw is known to cause a reduction in the survival of S. typhimurium and has been studied previously using bioluminescence as a monitor of cell viability (8). We have extended the studies of Ellison et al (8) to determine the effect of a competitive microflora upon survival of S. typhimurium following freeze injury.…”

Section: Resultsmentioning

confidence: 97%

A Competitive Microflora Increases the Resistance of Salmonella typhimurium to Inimical Processes: Evidence for a Suicide Response

Aldsworth

Sharman

Dodd

et al. 1998

Appl Environ Microbiol

View full text Add to dashboard Cite

The presence of a viable competitive microflora at cell densities of 108 CFU ml−1 protects an underlying population of 105 CFU of Salmonella typhimuriumml−1 against freeze injury. The mechanism of enhanced resistance was initially postulated to be via an RpoS-mediated adaptive response. By using an spvRA::luxCDABEreporter we have shown that although the onset of RpoS-mediated gene expression was brought forward by the addition of a competitive microflora, the time taken for induction was measured in hours. Since the protective effect of a competitive microflora is essentially instantaneous, the stationary-phase adaptive response is excluded as the physiological mechanism. The only instantaneous effect of the competitive microflora was a reduction in the percent saturation of oxygen from 100% to less than 10%. For both mild heat treatment (55°C) and freeze injury this change in oxygen tension affordsSalmonella a substantive (2 orders of magnitude) enhancement in survival. By reducing the levels of dissolved oxygen through active respiration, a competitive microflora reduces oxidative damage to exponential-phase cells irrespective of the inimical treatment. These results have led us to propose a suicide hypothesis for the destruction of rapidly growing cells by inimical processes. In essence, the suicide hypothesis proposes that a mild inimical process leads to the growth arrest of exponential-phase cells and to the decoupling of anabolic and catabolic metabolism. The result of this is a free radical burst which is lethal to unadapted cells.

show abstract

Section: Resultsmentioning

confidence: 97%

A Competitive Microflora Increases the Resistance of Salmonella typhimurium to Inimical Processes: Evidence for a Suicide Response

Aldsworth

Sharman

Dodd

et al. 1998

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Of special interest to the food microbiologist is the ability to monitor these processes directly in food, which makes the results much more relevant. As an example, recovery from cellular injury caused by freezing has been studied using luxAB recombinant Salmonella Typhimurium (20). Cells of this bacterium (10 5 /ml in peptone water) were frozen at -20°C and, after thawing, they were compared with a culture of non-frozen cells by measuring bioluminescence and by plate count.…”

Section: 3mentioning

confidence: 99%

Bioluminescence lights the way to food safety

Brovko

Griffiths

2003

SPIE Proceedings

View full text Add to dashboard Cite

The food industry is increasingly adopting food safety and quality management systems that are more proactive and preventive than those used in the past, which have tended to rely on end product testing and visual inspection. The regulatory agencies in many countries are promoting one such management tool, Hazard Analysis Critical Control Point (HACCP), as a way to achieve a safer food supply and as a basis for harmonization of trading standards. Verification that the process is safe must involve microbiological testing but the results are not, as yet, generated in real-time. Of all the rapid microbiological tests currently available, the only ones that come close to offering real-time results are bioluminescence-based methods. Recent developments in the application of bioluminescence for food safety issues are presented in this paper. These include the use of genetically engineered microorganisms with bioluminescent and fluorescent phenotypes as a real time indicator of physiological status of bacterial cells and survival of food-borne pathogens in food and food processing environments as well as novel bioluminescent-based methods for rapid detection of pathogens in food and environmental samples. Advantages and pitfalls of the methods are discussed.

show abstract

“…Photometry of light emitted by recombinant strains of bacteria which express luciferase and associated enzymes can monitor intracellular energy production (Ahmad & Stewart 1991;Ellison et al 1991). This novel and promising technique should be applicable to micro-organisms in aquatic environments although the oxidation of flavin mononucleotide by luciferase may represent an abnormal drain on the energy resources of cells.…”

Section: O T H E R M E T H O D Smentioning

confidence: 99%