Influence des conditions de culture préalables et de la présence du gènerpoSpour la survie deSalmonella typhimuriumen eau de mer exposée à la lumière solaire

2004 ◽  
Vol 50 (5) ◽  
pp. 341-350 ◽  
Author(s):  
K Maatouk ◽  
S Zaafrane ◽  
J M Gauthier ◽  
A Bakhrouf
Keyword(s):  
Stationary Phase ◽  
Salmonella Typhimurium ◽  
Minimal Medium ◽  
High Salinity ◽  
Sea Water ◽  
Culture Media ◽  
Solid Culture ◽  
Sunlight Irradiation ◽  
Low Salinity ◽  
Isogenic Strains

The effect of sunlight exposure on Salmonella typhimurium isogenic strains harboring an rpoS gene functional (rpoS+) or not functional (rpoS–) was investigated in microcosms of sterile sea water at 20 °C. The two strains rapidly lost their ability to produce colonies on solid culture media. The detrimental action of sunlight was more important when the salinity of sea water increased. The survival of stationary phase cells was influenced by RpoS. Bacteria grown in media with high salinity or osmolarity and transferred to sea water in stationary phase were more resistant to irradiation than those grown in media with low salinity. Prior growth under oxidative (0.2 mmol/L of H2O2) or amino acid starved (minimal medium) conditions did not modify the survival of either strain when they were exposed to sunlight. Bacteria were more resistant when cells were incubated in sea water in the dark prior to being exposed to sunlight. The resistance to sunlight irradiation was also greater in clones of both strains isolated from microcosms exposed to sunlight for 90 min, then further inoculated into sea water and reexposed to sunlight.Key words: Salmonella typhimurium, sea water, sunlight, rpoS, σs.

scholarly journals The response of the limpet, Patella vulgata L., to waters of different salinities

1957 ◽  
Vol 36 (1) ◽  
pp. 121-128 ◽  
Author(s):  
D. C. Arnold
Keyword(s):  
Fresh Water ◽  
High Salinity ◽  
Positive Response ◽  
Sea Water ◽  
High Tide ◽  
Negative Response ◽  
Normal Response ◽  
Patella Vulgata ◽  
Low Salinity

Patella vulgata gives a positive response to splashing with sea water or water of high salinity, and a negative response to fresh water or water of low salinity. The intensity of the positive response broadly corresponds with the salinity of the water used. There is a greater response to splash and a greater tolerance to reduced salinity in limpets from high-tide than in those from low-tide regions. A positive response is given to NaCl solutions of concentrations approximately equivalent to sea water, while a supra-normal response is given to concentrations somewhat above that of sea water. The perception of salinity is by receptors in the cephalic tentacles and mantle fringe.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

scholarly journals Characterization of Drug-Resistant Lipid-Dependent Differentially Detectable Mycobacterium tuberculosis

2021 ◽  
Vol 10 (15) ◽  
pp. 3249
Author(s):  
Annelies W. Mesman ◽  
Seung-Hun Baek ◽  
Chuan-Chin Huang ◽  
Young-Mi Kim ◽  
Sang-Nae Cho ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Culture Media ◽  
Multidrug Resistant ◽  
Culture Conditions ◽  
Sputum Smear ◽  
Smear Microscopy ◽  
Solid Culture ◽  
Lowenstein Jensen ◽  
Genetic Mechanisms ◽  
Lipid Resuscitation

An estimated 15–20% of patients who are treated for pulmonary tuberculosis (TB) are culture-negative at the time of diagnosis. Recent work has focused on the existence of differentially detectable Mycobacterium tuberculosis (Mtb) bacilli that do not grow under routine solid culture conditions without the addition of supplementary stimuli. We identified a cohort of TB patients in Lima, Peru, in whom acid-fast bacilli could be detected by sputum smear microscopy, but from whom Mtb could not be grown in standard solid culture media. When we attempted to re-grow Mtb from the frozen sputum samples of these patients, we found that 10 out of 15 could be grown in a glycerol-poor/lipid-rich medium. These fell into the following two groups: a subset that could be regrown in glycerol after “lipid-resuscitation”, and a group that displayed a heritable glycerol-sensitive phenotype that were unable to grow in the presence of this carbon source. Notably, all of the glycerol-sensitive strains were found to be multidrug resistant. Although whole-genome sequencing of the lipid-resuscitated strains identified 20 unique mutations compared to closely related strains, no single genetic lesion could be associated with this phenotype. In summary, we found that lipid-based media effectively fostered the growth of Mtb from a series of sputum smear-positive samples that were not culturable in glycerol-based Lowenstein–Jensen or 7H9 media, which is consistent with Mtb’s known preference for non-glycolytic sources during infection. Analysis of the recovered strains demonstrated that both genetic and non-genetic mechanisms contribute to the observed differential capturability, and suggested that this phenotype may be associated with drug resistance.

Carbon-Isotope, Diatom, and Pollen Evidence for Late Holocene Salinity Change in a Brackish Marsh in the San Francisco Estuary

2001 ◽  
Vol 55 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Roger Byrne ◽  
B. Lynn Ingram ◽  
Scott Starratt ◽  
Frances Malamud-Roam ◽  
Joshua N. Collins ◽  
...  
Keyword(s):  
San Francisco ◽  
High Salinity ◽  
Carbon Isotopic Composition ◽  
Brackish Marsh ◽  
San Francisco Estuary ◽  
Freshwater Inflow ◽  
Water Diversion ◽  
Freshwater Flow ◽  
Low Salinity ◽  
Carbon Isotopic

AbstractAnalysis of diatoms, pollen, and the carbon-isotopic composition of a sediment core from a brackish marsh in the northern part of the San Francisco Estuary has provided a paleosalinity record that covers the past 3000 yr. Changes in marsh composition and diatom frequencies are assumed to represent variations in freshwater inflow to the estuary. Three periods of relatively high salinity (low freshwater inflow) are indicated, 3000 to 2500 cal yr B.P., 1700 to 730 cal yr B.P., and ca. A.D. 1930 to the present. The most recent period of high salinity is primarily due to upstream storage and water diversion within the Sacramento–San Joaquin watershed, although drought may also have been a factor. The two earlier high-salinity periods are likely the result of reduced precipitation. Low salinity (high freshwater flow) is indicated for the period 750 cal yr B.P. to A.D. 1930.

Susceptibility of the Heat-, Acid-, and Bile-Adapted Vibrio vulnificus to Lethal Low-Salinity Stress

2006 ◽  
Vol 69 (12) ◽  
pp. 2924-2928 ◽  
Author(s):  
HIN-CHUNG WONG ◽  
SHU-HUI LIU
Keyword(s):  
Stationary Phase ◽  
Salinity Stress ◽  
Natural Environment ◽  
Food Processing ◽  
Vibrio Vulnificus ◽  
Pathogenic Bacterium ◽  
Protective Response ◽  
Low Salinity ◽  
Salinity Challenge ◽  
Insight Into

As a marine pathogenic bacterium that inhabits seawater or seafood, Vibrio vulnificus encounters low salinity and other stresses in the natural environment and during food processing. This investigation explores the cross-protective response of sublethal heat-, acid-, or bile-adapted V. vulnificus YJ03 against lethal low-salinity stress. Experimental results reveal that the acid (pH 4.4)– and heat (41°C)–adapted V. vulnificus were not cross-protected against the lethal low-salinity challenge (0.04% NaCl). The bile (0.05%)–adapted exponential- and stationary-phase cells were cross-protected against low salinity, whereas low-salinity (0.12% NaCl)–adapted stationary cells were sensitized against 12% bile stress. Results of this study provide further insight into the interaction between low salinity and other common stresses in V. vulnificus.

Growth potential of exponential- and stationary-phase Salmonella Typhimurium during sausage fermentation

Meat Science ◽  
2016 ◽  
Vol 121 ◽  
pp. 342-349 ◽  
Author(s):  
T. Birk ◽  
S. Henriksen ◽  
K. Müller ◽  
T.B. Hansen ◽  
S. Aabo
Keyword(s):  
Stationary Phase ◽  
Salmonella Typhimurium ◽  
Growth Potential

Spatial and seasonal variability of emergent aquatic insects and nearshore spiders in a subtropical estuary

2019 ◽  
Vol 70 (4) ◽  
pp. 541 ◽  
Author(s):  
Martha J. Zapata ◽  
S. Mažeika P. Sullivan
Keyword(s):  
Aquatic Insects ◽  
High Salinity ◽  
Aquatic Insect ◽  
Freshwater Ecosystems ◽  
Dispersal Ability ◽  
Insect Community ◽  
Insect Communities ◽  
Low Salinity ◽  
Subtropical Estuary ◽  
Adult Aquatic Insects

Variability in the density and distribution of adult aquatic insects is an important factor mediating aquatic-to-terrestrial nutritional subsidies in freshwater ecosystems, yet less is understood about insect-facilitated subsidy dynamics in estuaries. We surveyed emergent (i.e. adult) aquatic insects and nearshore orb-weaving spiders of the families Tetragnathidae and Araneidae in a subtropical estuary of Florida (USA). Emergent insect community composition varied seasonally and spatially; densities were lower at high- than low-salinity sites. At high-salinity sites, emergent insects exhibited lower dispersal ability and a higher prevalence of univoltinism than low- and mid-salinity assemblages. Orb-weaving spider density most strongly tracked emergent insect density rates at low- and mid-salinity sites. Tetragnatha body condition was 96% higher at high-salinity sites than at low-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems and indicate that aquatic insects may provide important nutritional subsidies to riparian consumers despite their depressed abundance and diversity compared with freshwater ecosystems.

The opening response of mussels (Mytilus edulis) exposed to rising sea-water concentrations

1981 ◽  
Vol 61 (3) ◽  
pp. 667-678 ◽  
Author(s):  
John Davenport
Keyword(s):  
Mytilus Edulis ◽  
Sea Water ◽  
External Medium ◽  
Mantle Cavity ◽  
Low Salinity ◽  
Medium Exchange ◽  
Mantle Edge

When exposed to water of low salinity specimens of Mytilus edulis L. keep their shell valves tightly closed; they do not gape periodically to test the external medium. Exchange of salts and water between the mantle cavity and the environment is thus minimized. Rising salinities are registered by diffusion of salts to the tentaculate portion of the inhalent siphon and not to any other portion of the mantle edge or to any more deeply located structures.

scholarly journals Novobiocin Sensitivity of Salmonella typhimurium dam and/or seqA Mutants

2014 ◽  
Vol 63 (1) ◽  
pp. 51-56 ◽  
Author(s):  
ABDELWAHEB CHATTI ◽  
MERIEM ALOUI ◽  
JIHEN TAGOURTI ◽  
MOUADH MIHOUB ◽  
AHMED LANDOULSI
Keyword(s):  
Dna Methylation ◽  
Stationary Phase ◽  
Salmonella Typhimurium ◽  
The Other ◽  
Protein Profiles ◽  
Wild Type ◽  
Whole Cell ◽  
Expression Levels

This study was carried out to determine the effects of novobiocin, a gyrase inhibitor, on the growth, survival, motility and whole cell proteins of S. Typhimurium dam and/or seqA strains. Our results showed that the dam and seqA/dam mutants are the most sensitive to novobiocin, compared to wild type and seqA strains. Surprisingly, the motility of seqA mutants increased after exposure to novobiocin only in stationary phase cells. All the other strains showed a significant decrease in their motility. The analysis of protein profiles of all strains demonstrated several modifications as manifested by the alteration of the expression levels of certain bands. Our work is therefore of great interest in understanding the effects of novobiocin on S. Typhimurium and the involvement of DNA methylation.

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