Role of the rpoS gene in the survival of Salmonella enterica serovar Typhimurium in the marine environment Rôle du gène rpoS pour la survie de Salmonella enterica serovar Typhimurium dans l'environnement marin

Zaafrane, S.; Maatouk, K.
April 2012
Water Quality Research Journal of Canada (IWA Publishing);2012, Vol. 47 Issue 2, p186
Academic Journal
The survival of Salmonella enterica serovar Typhimurium rpoS+ and rpoS- exposed to sunlight or incubated in the dark was studied in a seawater microcosm and a diffusion chamber. The total number of bacteria and physiologically active ones were estimated by direct counting using epifluorescence microscopy, while cultivable bacteria were enumerated by plating onto an agar culture medium. The results obtained showed that the bacteria exposed to sunlight, either in the microcosm or in the diffusion chamber, exhibited a fast decline of cultivable cells, whereas the epifluorescence enumeration revealed a conservation of physiological activity after a total loss of cultivability. In a transparent diffusion chamber, the evolution of cultivable and physiological active bacteria was characterized by a diurnal decrease and a nocturnal stabilization in the count levels, reflecting the effect of phototoxicity on the survival of Salmonella. The transformation and persistence of a physiological active state and cellular integrity in the diffusion chamber or the microcosm showed a clear dependence on the presence of the rpoS gene. Survival in the dark was also characterized by a decrease of cultivability; however, this was significantly inferior to that observed in bacteria exposed to sunlight. This loss of cultivability was accompanied by the preservation of a physiologically active state. The study of seasonal survival carried out in the transparent diffusion chamber was characterized by an enhanced survival of the rpoS+ strain in comparison with the rpo- mutant. The highest survival rates were obtained in the autumn, thus highlighting the relevant effect of temperature and exposure to sunlight on the persistence of bacteria in seawater.


Related Articles

  • INVENTORY THE MICROCOSMOS! Guerrero, Ricardo; Margulis, Lynn; Dolan, Michael // Whole Earth;Fall2000, Issue 102, p14 

    Calls for a systematic classification of microcosms, the organisms that require a microscope for their proper visualization. Investigations on the extent of biodiversity; Information on Linnean rule of taxonomy; Efforts to name and describe the microbes of Reticulitermes; Association between...

  • Culturability as an Indicator of Succession in Microbial Communities. Garland, J.L.; Cook, K.L.; Adams, J.L.; Kerkhof, L. // Microbial Ecology;Aug2001, Vol. 42 Issue 2, p150 

    Successional theory predicts that opportunistic species with high investment of energy in reproduction and wide niche width will be replaced by equilibrium species with relatively higher investment of energy in maintenance and narrower niche width as communities develop. Since the ability to...

  • Aquatic Actinomycete-Fungal Interactions and Their Effects on Organic Matter Decomposition: A Microcosm Study. Wohl, D. L.; McArthur, J. V. // Microbial Ecology;Oct2001, Vol. 42 Issue 3, p446 

    The role of fungi in the decomposition of organic matter in streams has been well examined, although the role of bacterial antagonists in such processes has gained little attention. To examine bacterial-fungal interactions, experiments involving pairwise combinations of four actinomycete...

  • Effects of Chemically Enhanced Water-Accommodated Fraction of Iranian Heavy Crude Oil on Periphytic Microbial Communities in Microcosm Experiment. Baek, Seung; Son, Moonho; Shim, Won // Bulletin of Environmental Contamination & Toxicology;May2013, Vol. 90 Issue 5, p605 

    Exposure experiments were conducted to determine the effects of an oil spill on a periphytic microbial community with the chemically enhanced water-accommodated fraction (CEWAF) of Iranian Heavy Crude oil in a microcosm containing artificial benthic substrates. Bacteria and heterotrophic...

  • Isolation and characterization of bacteria from soil contaminated with diesel oil and the possible use of these in autochthonous bioaugmentation. Yukiya Ito; Isao Yumoto; Hidetoshi Okuyama // World Journal of Microbiology & Biotechnology;Dec2007, Vol. 23 Issue 12, p1739 

    Abstract  Two bacterial species (isolates N and O) were isolated from a paddy soil microcosm that had been artificially contaminated with diesel oil to which extrinsic Pseudomonas aeruginosa strain WatG, had been added exogenously. One bacterial species (isolate J) was isolated...

  • The survival response of Escherichia coli K12 in a natural environment. Na, S. H.; Miyanaga, K.; Unno, H.; Tanji, Y. // Applied Microbiology & Biotechnology;Aug2006, Vol. 72 Issue 2, p386 

    To verify the hypothesis of cryptic growth and viable but nonculturable (VBNC) state, survival responses of Escherichia coli cells were examined under oligotrophic microcosm conditions for an extended period. In the case of filtered distilled water at 4�C, E. coli cells definitely entered...

  • Bacterial pathogenesis: There is no I in team. David, Rachel // Nature Reviews Microbiology;Apr2013, Vol. 11 Issue 4, p223 

    The article reports on the two identified subpopulations of Salmonella enterica serovar typhimurium such as a slow-growing one that expresses type III secretion system 1 (T3SS1) and fast-growing one that do not express T3SS1.

  • Cefotaxime-Resistant Salmonella enterica in Travelers Returning from Thailand to Finland. Gunell, Marianne; Aulu, Laura; Jalava, Jari; Lukinmaa-Åberg, Susanna; Österblad, Monica; Ollgren, Jukka; Huovinen, Pentti; Siitonen, Anja; Hakanen, Antti J. // Emerging Infectious Diseases;Jul2014, Vol. 20 Issue 7, p1214 

    During 1993-2011, cefotaxime resistance among Salmonella enterica isolates from patients in Finland increased substantially. Most of these infections originated in Thailand; many were qnr positive and belonged to S. enterica serovar Typhimurium and S. enterica monophasic serovar 4,[5],12:i:-....

  • Cadmium fate in bacterial microcosms. Remacle, J.; Houba, C.; Ninane, J. // Water, Air & Soil Pollution;Nov1982, Vol. 18 Issue 4, p455 

    Mixed bacterial cultures were incubated in chemostats to mimic natural conditions as close as possible. When they had reached a steady state, they received a flux containing 0.5 mg Cd l. The responses of bacterial systems were examined at 20 and 10°C. Moreover, the Cd accumulation by bacteria...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics