Survie du Salmonella paratyphi B et du Pseudomonas aeruginosa dans l'eau de mer après incubation ou lavage en présence d'osmolytes

1992 ◽  
Vol 38 (7) ◽  
pp. 690-693 ◽  
Author(s):  
Amina Bakhrouf ◽  
Moncef Jeddi ◽  
Michel J. Gauthier
Keyword(s):  
Pseudomonas Aeruginosa ◽  
B Cells ◽  
Key Words ◽  
Marine Environment ◽  
Glycine Betaine ◽  
Osmotic Shock ◽  
Organic Osmolytes ◽  
High Osmolarity ◽  
Paratyphi B ◽  
Survival Potential

The authors have compared the survival in seawater of Salmonella paratyphi B and Pseudomonas aeruginosa cells grown at low or high osmolarity, in the presence of organic osmolytes: glycine betaine, choline, proline, and glutamate. The four substrates enhanced the survival potential of S. paratyphi B while only glycine betaine protected P. aeruginosa. In addition only S. paratyphi B cells were more resistant after a preliminary growth at high osmolarity. Both bacteria were sensitive to osmotic down-shock, sensitization of S. paratyphi B being inversely proportional (p ≥ 0.01) to the osmolarity of the medium used to wash cells. The transit in wastewater, at low osmolarity, can therefore modify the behavior of these pathogens in the marine environment. Key words: Salmonella paratyphi B, Pseudomonas aeruginosa, survival, seawater, osmotic shock.

Effect of incubation of Escherichia coli cells with halophyte extracts on their subsequent survival in seawater

1992 ◽  
Vol 38 (8) ◽  
pp. 838-842 ◽  
Author(s):  
G. N. Flatau ◽  
R. L. Clement ◽  
M. J. Gauthier ◽  
D. C. Puel
Keyword(s):  
Escherichia Coli ◽  
Key Words ◽  
Enteric Bacteria ◽  
Marine Organisms ◽  
Taxonomic Position ◽  
Organic Osmolytes ◽  
Aqueous Extracts ◽  
High Osmolarity ◽  
Escherichia Coli Cells ◽  
Key Words Escherichia Coli

Organic osmolytes are utilized by enteric bacteria for their survival when entering a high-osmolarity medium such as seawater. As these are commonly synthetized by marine organisms (fauna and flora), the purpose of this work was to investigate the effects of aqueous extracts from some marine phytoplanktonic species, alga, and phanerogam on the survival of Escherichia coli cells in seawater. Some of the tested halophyte extracts greatly enhanced survival, whereas others were inhibitory. The efficiency of the extracts could not be correlated to the taxonomic position of the halophyte or to the presence of Dragendorff-positive compounds known to be osmoprotective. Key words: Escherichia coli, survival, seawater, halophytes, osmoprotection.

scholarly journals BetS Is a Major Glycine Betaine/Proline Betaine Transporter Required for Early Osmotic Adjustment in Sinorhizobium meliloti

2002 ◽  
Vol 184 (10) ◽  
pp. 2654-2663 ◽  
Author(s):  
Alexandre Boscari ◽  
Karine Mandon ◽  
Laurence Dupont ◽  
Marie-Christine Poggi ◽  
Daniel Le Rudulier
Keyword(s):  
Glycine Betaine ◽  
Sinorhizobium Meliloti ◽  
Transport Systems ◽  
High Osmolarity ◽  
Carnitine Transporter ◽  
Rapid Acquisition ◽  
Common Structure ◽  
Pcr Product ◽  
Transport Kinetic ◽  
In Cells

ABSTRACT Hybridization to a PCR product derived from conserved betaine choline carnitine transporter (BCCT) sequences led to the identification of a 3.4-kb Sinorhizobium meliloti DNA segment encoding a protein (BetS) that displays significant sequence identities to the choline transporter BetT of Escherichia coli (34%) and to the glycine betaine transporter OpuD of Bacillus subtilis (30%). Although the BetS protein shows a common structure with BCCT systems, it possesses an unusually long hydrophilic C-terminal extension (169 amino acids). After heterologous expression of betS in E. coli mutant strain MKH13, which lacks choline, glycine betaine, and proline transport systems, both glycine betaine and proline betaine uptake were restored, but only in cells grown at high osmolarity or subjected to a sudden osmotic upshock. Competition experiments demonstrated that choline, ectoine, carnitine, and proline were not effective competitors for BetS-mediated betaine transport. Kinetic analysis revealed that BetS has a high affinity for betaines, with Km s of 16 ± 2 μM and 56 ± 6 μM for glycine betaine and proline betaine, respectively, in cells grown in minimal medium with 0.3 M NaCl. BetS activity appears to be Na+ driven. In an S. meliloti betS mutant, glycine betaine and proline betaine uptake was reduced by about 60%, suggesting that BetS represents a major component of the overall betaine uptake activities in response to salt stress. β-Galactosidase activities of a betS-lacZ strain grown in various conditions showed that betS is constitutively expressed. Osmotic upshock experiments performed with wild-type and betS mutant cells, treated or not with chloramphenicol, indicated that BetS-mediated betaine uptake is the consequence of immediate activation of existing proteins by high osmolarity, most likely through posttranslational activation. Growth experiments underscored the crucial role of BetS as an emerging system involved in the rapid acquisition of betaines by S. meliloti subjected to osmotic upshock.

scholarly journals Evaluación del método dilución neutralización aplicado a un desinfectante según la Norma Técnica Colombiana 5473 de 2007

2012 ◽  
Vol 17 (1) ◽  
pp. 72
Author(s):  
Janeth Arias-Palacios ◽  
Libardo Hernandez-Esquivel ◽  
Juan Carlos Marín-Díaz ◽  
Natalia Navarro-Peña ◽  
Natalia Santos-Arévalo
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Key Words ◽  
Bactericidal Activity ◽  
Bovine Serum ◽  
Enterococcus Hirae ◽  
Experimental Conditions ◽  
Logarithmic Reduction

<strong>Objective</strong>. Evaluate the dilution-neutralization method proposed in the Colombian Technical Norm 5473/07, by using a gel, alcoholbased disinfectant. <strong>Materials and methods</strong>. This study was done using Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 6538, and Enterococcus hirae ATCC 10541 as the assay microorganisms. The study was carried out at 20±1°C as obligatory temperature and additionally at 36±1°C. Four contact times between microorganisms and the disinfectant were evaluated (0, 2, 5 and 10 minutes). The assay was done both under clean conditions (0.3 g/L of bovine serum albumin), and unclean conditions (3 g/L of bovine serum albumin and 3g/L of sheep erythrocytes). <strong>Results</strong>. The implementation of this method produced precise results in all of the six<br />repetitions used during the assay. The obtained results demonstrated a logarithmic reduction higher than five, demonstrating the bactericidal activity exerted by the disinfectant on the control microorganisms. The established experimental conditions and methodology did not affect negatively the growth of any of the strains of microorganisms. Similarly, the neutralizing used did not inhibit the development of the microorganisms of the assay.<strong> Conclusions</strong>. The method was verified by means of the fulfillment of the limits set by the rule. Our results suggest that the method evaluated by means of the implementation of the protocol established in the Colombian Technical Norm 5473/07, allows evaluating the effectiveness of a disinfectant under selected and controlled experimental conditions.<br /><br /><strong>Key words</strong>: disinfection, clean conditions, unclean conditions, dilution-neutralization method, logarithmic reduction.

scholarly journals Identification of Two Gene Clusters and a Transcriptional Regulator Required for Pseudomonas aeruginosa Glycine Betaine Catabolism

2007 ◽  
Vol 190 (8) ◽  
pp. 2690-2699 ◽  
Author(s):  
Matthew J. Wargo ◽  
Benjamin S. Szwergold ◽  
Deborah A. Hogan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glycine Betaine ◽  
Transcriptional Regulator ◽  
Gene Clusters ◽  
Sole Source ◽  
Nmr Studies ◽  
Demethylase Activity ◽  
Growth Experiments ◽  
Insight Into ◽  
C Nmr

ABSTRACT Glycine betaine (GB), which occurs freely in the environment and is an intermediate in the catabolism of choline and carnitine, can serve as a sole source of carbon or nitrogen in Pseudomonas aeruginosa. Twelve mutants defective in growth on GB as the sole carbon source were identified through a genetic screen of a nonredundant PA14 transposon mutant library. Further growth experiments showed that strains with mutations in two genes, gbcA (PA5410) and gbcB (PA5411), were capable of growth on dimethylglycine (DMG), a catabolic product of GB, but not on GB itself. Subsequent nuclear magnetic resonance (NMR) experiments with 1,2-13C-labeled choline indicated that these genes are necessary for conversion of GB to DMG. Similar experiments showed that strains with mutations in the dgcAB (PA5398-PA5399) genes, which exhibit homology to genes that encode other enzymes with demethylase activity, are required for the conversion of DMG to sarcosine. Mutant analyses and 13C NMR studies also confirmed that the soxBDAG genes, predicted to encode a sarcosine oxidase, are required for sarcosine catabolism. Our screen also identified a predicted AraC family transcriptional regulator, encoded by gbdR (PA5380), that is required for growth on GB and DMG and for the induction of gbcA, gbcB, and dgcAB in response to GB or DMG. Mutants defective in the previously described gbt gene (PA3082) grew on GB with kinetics similar to those of the wild type in both the PAO1 and PA14 strain backgrounds. These studies provided important insight into both the mechanism and the regulation of the catabolism of GB in P. aeruginosa.

scholarly journals Homeostasis and Catabolism of Choline and Glycine Betaine: Lessons from Pseudomonas aeruginosa

2013 ◽  
Vol 79 (7) ◽  
pp. 2112-2120 ◽  
Author(s):  
Matthew J. Wargo
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glycine Betaine ◽  
Primary Role ◽  
Decision Point ◽  
Catabolic Pathways ◽  
Content Type ◽  
Regulatory Pathways ◽  
Multistep Conversion ◽  
Two Kingdoms ◽  
The Impact

ABSTRACTMost sequenced bacteria possess mechanisms to import choline and glycine betaine (GB) into the cytoplasm. The primary role of choline in bacteria appears to be as the precursor to GB, and GB is thought to primarily act as a potent osmoprotectant. Choline and GB may play accessory roles in shaping microbial communities, based on their limited availability and ability to enhance survival under stress conditions. Choline and GB enrichment near eukaryotes suggests a role in the chemical relationships between these two kingdoms, and some of these interactions have been experimentally demonstrated. While many bacteria can convert choline to GB for osmoprotection, a variety of soil- and water-dwelling bacteria have catabolic pathways for the multistep conversion of choline, via GB, to glycine and can thereby use choline and GB as sole sources of carbon and nitrogen. In these choline catabolizers, the GB intermediate represents a metabolic decision point to determine whether GB is catabolized or stored as an osmo- and stress protectant. This minireview focuses on this decision point inPseudomonas aeruginosa, which aerobically catabolizes choline and can use GB as an osmoprotectant and a nutrient source.P. aeruginosais an experimentally tractable and ecologically relevant model to study the regulatory pathways controlling choline and GB homeostasis in choline-catabolizing bacteria. The study ofP. aeruginosaassociations with eukaryotes and other bacteria also makes this a powerful model to study the impact of choline and GB, and their associated regulatory and catabolic pathways, on host-microbe and microbe-microbe relationships.

scholarly journals Evidence of a New Role for the High-Osmolarity Glycerol Mitogen-Activated Protein Kinase Pathway in Yeast: Regulating Adaptation to Citric Acid Stress

2004 ◽  
Vol 24 (8) ◽  
pp. 3307-3323 ◽  
Author(s):  
Clare L. Lawrence ◽  
Catherine H. Botting ◽  
Robin Antrobus ◽  
Peter J. Coote
Keyword(s):  
Citric Acid ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Osmotic Shock ◽  
Acid Stress ◽  
Tca Cycle ◽  
Mitogen Activated Protein Kinase ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
Mitogen Activated Protein

ABSTRACT Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite minor activation of glycerol biosynthesis, the inhibitory effect of citric acid was not due to an osmotic shock. HOG1 negatively regulated the expression of a number of proteins in response to citric acid stress, including Bmh1p. Evidence suggests that BMH1 is induced by citric acid to counteract the effect of amino acid starvation. In addition, deletion of BMH2 rendered cells sensitive to citric acid. Deletion of the transcription factor MSN4, which is known to be regulated by Bmh1p and Hog1p, had a similar effect. HOG1 was also required for citric acid-induced up-regulation of Ssa1p and Eno2p. To counteract the cation chelating activity of citric acid, the plasma membrane Ca2+ channel, CCH1, and a functional vacuolar membrane H+-ATPase were found to be essential for optimal adaptation. Also, the transcriptional regulator CYC8, which mediates glucose derepression, was required for adaptation to citric acid to allow cells to metabolize excess citrate via the tricarboxylic acid (TCA) cycle. Supporting this, Mdh1p and Idh1p, both TCA cycle enzymes, were up-regulated in response to citric acid.

scholarly journals Msb2 Signaling Mucin Controls Activation of Cek1 Mitogen-Activated Protein Kinase in Candida albicans

2009 ◽  
Vol 8 (8) ◽  
pp. 1235-1249 ◽  
Author(s):  
Elvira Román ◽  
Fabien Cottier ◽  
Joachim F. Ernst ◽  
Jesús Pla
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Protein Kinase ◽  
Osmotic Shock ◽  
Mitogen Activated Protein Kinase ◽  
Hog Pathway ◽  
High Osmolarity ◽  
Cell Wall Biogenesis ◽  
Solid Media ◽  
Mitogen Activated Protein

ABSTRACT We have characterized the role that the Msb2 protein plays in the fungal pathogen Candida albicans by the use of mutants defective in the putative upstream components of the HOG pathway. Msb2, in cooperation with Sho1, controls the activation of the Cek1 mitogen-activated protein kinase under conditions that damage the cell wall, thus defining Msb2 as a signaling element of this pathway in the fungus. msb2 mutants display altered sensitivity to Congo red, caspofungin, zymolyase, or tunicamycin, indicating that this protein is involved in cell wall biogenesis. Msb2 (as well as Sho1 and Hst7) is involved in the transmission of the signal toward Cek1 mediated by the Cdc42 GTPase, as revealed by the use of activated alleles (Cdc42G12V) of this protein. msb2 mutants have a stronger defective invasion phenotype than sho1 mutants when tested on certain solid media that use mannitol or sucrose as a carbon source or under hypoxia. Interestingly, Msb2 contributes to growth under conditions of high osmolarity when both branches of the HOG pathway are altered, as triple ssk1 msb2 sho1 mutants (but not any single or double mutant) are osmosensitive. However, this phenomenon is independent of the presence of Hog1, as Hog1 phosphorylation, Hog1 translocation to the nucleus, and glycerol accumulation are not affected in this mutant following an osmotic shock. These results reveal essential functions in morphogenesis, invasion, cell wall biogenesis, and growth under conditions of high osmolarity for Msb2 in C. albicans and suggest the divergence and specialization of this signaling pathway in filamentous fungi.

scholarly journals Glycine Betaine Transmethylase Mutant of Pseudomonas aeruginosa

2002 ◽  
Vol 184 (15) ◽  
pp. 4301-4303 ◽  
Author(s):  
Ana L. Serra ◽  
Javier F. Mariscotti ◽  
José L. Barra ◽  
Gloria I. Lucchesi ◽  
Carlos E. Domenech ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Sequence Analysis ◽  
Glycine Betaine ◽  
Nitrogen Sources ◽  
Open Reading Frame ◽  
Carbon And Nitrogen Sources ◽  
Reading Frame ◽  
Carbon And Nitrogen ◽  
Molecular Approaches ◽  
Knockout Gene

ABSTRACT The gene for glycine betaine transmethylase (gbt) was identified in Pseudomonas aeruginosa strain Fildes III by biochemical, physiological, and molecular approaches. Based on sequence analysis, the knockout gene corresponded to an open reading frame (ORF) named PA3082 in the genome of P. aeruginosa PAO1. The translated product of this ORF displayed similarity to transferases of different microorganisms. Mutation in gbt blocked the utilization of choline and glycine betaine as carbon and nitrogen sources.

scholarly journals Glycine Betaine Fluxes inLactobacillus plantarumduring Osmostasis and Hyper- and Hypo-osmotic Shock

1996 ◽  
Vol 271 (17) ◽  
pp. 10060-10065 ◽  
Author(s):  
Erwin Glaasker ◽  
Wil N. Konings ◽  
Bert Poolman
Keyword(s):  
Glycine Betaine ◽  
Osmotic Shock
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