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Biofouling Jun 2004This communication focuses on the efficacy of a specific lytic phage, phage Phi S1, as a control agent of Pseudomonas fluorescens biofilms. The effect of phage infection...
This communication focuses on the efficacy of a specific lytic phage, phage Phi S1, as a control agent of Pseudomonas fluorescens biofilms. The effect of phage infection temperature and the host growth temperature were evaluated. The results obtained showed that the phage infection process was temperature dependent and that the optimum temperature of infection of planktonic cells and biofilms was 26 degrees C. At this temperature, bacteriophage Phi S1, at a multiplicity of infection (MOI) of 0.5 infected both planktonic cells and biofilms causing a biomass reduction of about 85% in both cases.
Topics: Bacteriophages; Biofilms; Biomass; Cell Division; Plankton; Pseudomonas fluorescens; Temperature
PubMed: 15545062
DOI: 10.1080/08927010410001723834 -
International Journal of Food... Feb 2008Application of antimicrobial chemicals is a general procedure in the cleaning and disinfection of food-contacting surfaces. Adhesion to glass surfaces and chemically...
Application of antimicrobial chemicals is a general procedure in the cleaning and disinfection of food-contacting surfaces. Adhesion to glass surfaces and chemically induced detachment of Pseudomonas fluorescens ATCC 13525(T) were studied in situ, under flow conditions, in a well-controlled parallel plate flow chamber (PPFC). Ortho-phthalaldehyde (OPA) and cetyltrimethyl ammonium bromide (CTAB) were applied separately, at several concentrations, to attached bacteria and their subsequent detachment was monitored. Following treatments the remaining adhered bacteria were characterized in terms of viability and cell size. Simultaneously, the planktonic cell surface was characterized in order to correlate PPFC results with thermodynamic approaches for adhesion evaluation, and surface free energy of chemically treated cells with adhesion strength. About 2.8x10(6) cells/cm(2) adhered to the glass surface after 30 min of bacterial flow, although thermodynamic analyses evidenced unfavourable adhesion. The independent application of OPA and CTAB promoted bacterial detachment to a small extent (16% of total cells). The remaining adhering bacteria were totally non-viable for OPA> or =0.75 mM and CTAB> or =0.25 mM, showing a lack of correlation between bacterial viability and detachment. The cellular size decreased as attachment proceeded and with chemical treatment. Both chemicals altered the cell surface properties, increasing the cell-glass adhesion strength, and promoting the emergence of polar characteristics. The overall results emphasize that OPA and CTAB were markedly ineffective in removing glass-attached P. fluorescens, demonstrating that bacteria can be non-viable but remain strongly attached to the adhesion surface.
Topics: Bacterial Adhesion; Biofilms; Cetrimonium Compounds; Colony Count, Microbial; Dermoscopy; Disinfectants; Dose-Response Relationship, Drug; Glass; Pseudomonas fluorescens; Surface-Active Agents; Water Movements; o-Phthalaldehyde
PubMed: 18155793
DOI: 10.1016/j.ijfoodmicro.2007.11.041 -
Food Microbiology May 2014The Pseudomonas fluorescens group comprises several closely related species that are involved in food contamination and spoilage. Specifically, the interest in...
The Pseudomonas fluorescens group comprises several closely related species that are involved in food contamination and spoilage. Specifically, the interest in P. fluorescens as a spoiler of dairy products increased after the cases of "blue mozzarella" that occurred in Italy in 2010. A Multilocus Sequence Typing (MLST) scheme was developed and applied to characterise 136 isolates (reference strains and food borne isolates) at strain level, to reveal the genetic relationships among them and to disclose any possible genetic clustering of phenotypic markers involved in food spoilage (protease, lipase, lecithinase activities and pigmented or fluorescent molecule production). The production of dark blue diffusible pigment was evaluated on several bacterial culture media and directly on mozzarella cheese. The MLST scheme provided precise genotyping at the strain level, and the population analyses of the concatenated sequences allowed major taxa to be defined. This approach was revealed to be suitable for tracking the strains according to their origin, such as dairy plants or food matrices. The genetic analysis revealed the presence of a connection between the blue pigment production and a specific phylogenetic cluster. The development of the online database specific to the P. fluorescens group (http://pubmlst.org/pfluorescens) will facilitate the application of the scheme and the sharing of the data.
Topics: Cheese; Food Contamination; Molecular Sequence Data; Multilocus Sequence Typing; Phylogeny; Pseudomonas fluorescens
PubMed: 24387861
DOI: 10.1016/j.fm.2013.11.012 -
Plant Biology (Stuttgart, Germany) Jan 2007Plants have evolved strategies of stimulating and supporting specific groups of antagonistic microorganisms in the rhizosphere as a defense against diseases caused by... (Review)
Review
Plants have evolved strategies of stimulating and supporting specific groups of antagonistic microorganisms in the rhizosphere as a defense against diseases caused by soilborne plant pathogens owing to a lack of genetic resistance to some of the most common and widespread soilborne pathogens. Some of the best examples of natural microbial defense of plant roots occur in disease suppressive soils. Soil suppressiveness against many different diseases has been described. Take-all is an important root disease of wheat, and soils become suppressive to take-all when wheat or barley is grown continuously in a field following a disease outbreak; this phenomenon is known as take-all decline (TAD). In Washington State, USA and The Netherlands, TAD results from the enrichment during monoculture of populations of 2,4-diacetylphloroglucinol (2,4-DAPG)-producing Pseudomonas fluorescens to a density of 10 (5) CFU/g of root, the threshold required to suppress the take-all pathogen, Gaeumannomyces graminis var. tritici. 2,4-DAPG-producing P. fluorescens also are enriched by monoculture of other crops such as pea and flax, and evidence is accumulating that 2,4-DAPG producers contribute to the defense of plant roots in many different agroecosystems. At this time, 22 distinct genotypes of 2,4-DAPG producers (designated A - T, PfY and PfZ) have been defined by whole-cell repetitive sequence-based (rep)-PCR analysis, restriction fragment length polymorphism (RFLP) analysis of PHLD, and phylogenetic analysis of PHLD, but the number of genotypes is expected to increase. The genotype of an isolate is predictive of its rhizosphere competence on wheat and pea. Multiple genotypes often occur in a single soil and the crop species grown modulates the outcome of the competition among these genotypes in the rhizosphere. 2,4-DAPG producers are highly effective biocontrol agents against a variety of plant diseases and ideally suited for serving as vectors for expressing other biocontrol traits in the rhizosphere.
Topics: Cluster Analysis; Genes, Bacterial; Genotype; Pest Control, Biological; Phloroglucinol; Plant Diseases; Plant Roots; Pseudomonas fluorescens; Soil Microbiology; Triticum; Washington
PubMed: 17058178
DOI: 10.1055/s-2006-924473 -
Aquatic Toxicology (Amsterdam,... Mar 2013A global proteomic evaluation of the response of the marine bacterium Pseudomonas fluorescens BA3SM1 to Cd, Zn and Cu was performed by two dimensional gel...
A global proteomic evaluation of the response of the marine bacterium Pseudomonas fluorescens BA3SM1 to Cd, Zn and Cu was performed by two dimensional gel electrophoresis followed by mass spectrometry. When stressed with Cd, the most toxic metal for P. fluorescens BA3SM1, cell growth is rapidly affected and the number of proteins up-regulated (sixteen for 0.4 mM Cd) remains low in comparison with results obtained for Zn and Cu (twenty eight for 1.5mM Zn and forty four for 1.5 mM Cu). The changes in protein expression indicate that the cell adapts to metals by inducing essentially seven defense mechanisms: cell aggregation/biofilm formation (Zn=Cu>Cd); modification of envelope properties to increase the extracellular metal biosorption and/or control the uptake of metal (Cu>Zn); metal export (Cd=Zn and probably Cu); responses to oxidative stress (Cu>Zn>Cd); intracellular metal sequestration (Zn=Cu and probably Cd); hydrolysis of abnormally folded proteins (Cd=Cu), and the over-synthesis of proteins inhibited by metal (Cd>Cu>Zn). To the best of our knowledge, this is the first report showing that a marine P. fluorescens is able to acquire a metal-resistant phenotype, making the strain BA3SM1 a promising agent for bioremediation processes.
Topics: Gene Expression Regulation, Bacterial; Metals; Proteomics; Pseudomonas fluorescens; Water Pollutants, Chemical
PubMed: 23314334
DOI: 10.1016/j.aquatox.2012.12.006 -
Journal of Microbiology (Seoul, Korea) Jun 2009CopRS/CopABCD is one of the known systems that control copper homeostasis in bacteria. Although CopRS/CopABCD homologues are found to exist in Pseudomonas fluorescens,...
CopRS/CopABCD is one of the known systems that control copper homeostasis in bacteria. Although CopRS/CopABCD homologues are found to exist in Pseudomonas fluorescens, the potential role of this system in P. fluorescens has not been investigated. In this study a genetic cluster, consisting of copR, S, C, and D but lacking copAB, was identified in a pathogenic P. fluorescens strain (TSS) isolated from diseased fish. The copRSCD cluster was demonstrated to be required for full copper resistance and regulated at the transcription level by Cu. Expression of copCD is regulated directly by the two-component response regulator CopR, which also regulates its own expression. Interruption of the regulated expression of copR affected bacterial growth, biofilm formation, and tissue dissemination and survival. A mutant CopR, which lacks the N-terminal signal receiver domain and is constitutively active, was found to have an attenuating effect on bacterial virulence when expressed in TSS. To our knowledge, this is the first report that suggests a link between CopR and bacterial pathogenicity in P. fluorescens.
Topics: Animals; Bacterial Proteins; Biofilms; Copper; DNA, Bacterial; Drug Resistance, Bacterial; Fish Diseases; Fishes; Gene Expression Regulation, Bacterial; Genes, Bacterial; Membrane Transport Proteins; Microbial Viability; Molecular Sequence Data; Multigene Family; Pseudomonas Infections; Pseudomonas fluorescens; Sequence Analysis, DNA; Signal Transduction; Virulence
PubMed: 19557345
DOI: 10.1007/s12275-008-0278-9 -
Archiv Fur Mikrobiologie Apr 1973
Topics: Catalase; Lethal Dose 50; Lipase; Mutation; Oxidoreductases; Phosphatidylcholines; Phospholipases; Pseudomonas; Pseudomonas fluorescens; Temperature; Virulence
PubMed: 4633837
DOI: 10.1007/BF00408925 -
Applied and Environmental Microbiology Oct 1988The fate of spontaneous chromosomal rifampin-resistant (Rifr) mutants of Pseudomonas putida and Pseudomonas fluorescens in sterile and live organic soil from which they...
The fate of spontaneous chromosomal rifampin-resistant (Rifr) mutants of Pseudomonas putida and Pseudomonas fluorescens in sterile and live organic soil from which they were isolated was studied. In sterile native-soil assays, a Rifr mutant of P. putida showed no decrease in competitive fitness when compared with the wild-type parent. However, mutants of P. fluorescens were of two general categories. Group 1 showed no difference from the wild type in terms of growth rate, competitive fitness, and membrane protein composition. Group 2 showed a slower growth rate in both minimal and enriched media and an altered membrane protein profile. These mutants also demonstrated decreased competitive fitness compared with the wild-type strain. In live soil, the Rifr P. putida strain persisted throughout the 38-day test period with a decay rate of 0.7 log10 CFU/g of soil per 10 days. A group 1 Rifr P. fluorescens mutant maintained its inoculated titer for 7 to 10 days and then decayed at a rate of 0.2 to 0.4 log10 CFU/g of soil per 10 days. A group 2 Rifr P. fluorescens mutant remained at its titer for 1 to 5 days before decaying at a two- to threefold-faster rate. These findings indicate that rifampin resistance may not be an innocuous mutation in some pseudomonads and that marked strains should be compared with wild-type parents before being used as monitors of parental strain survival. Colonization of sterile soil with either the wild-type or mutant strain precluded normal colonization of the second added strain.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Drug Resistance, Microbial; Membrane Proteins; Mutation; Pseudomonas; Pseudomonas fluorescens; Rifampin; Soil Microbiology
PubMed: 3144244
DOI: 10.1128/aem.54.10.2432-2438.1988 -
The Journal of Biological Chemistry Dec 1967
Topics: Chromatography, DEAE-Cellulose; Enzyme Stability; Hydrogen-Ion Concentration; N-Glycosyl Hydrolases; Pseudomonas fluorescens; Substrate Specificity
PubMed: 12325375
DOI: No ID Found -
PloS One 2011Many soil-inhabiting bacteria are known to produce secondary metabolites that can suppress microorganisms competing for the same resources. The production of...
BACKGROUND
Many soil-inhabiting bacteria are known to produce secondary metabolites that can suppress microorganisms competing for the same resources. The production of antimicrobial compounds is expected to incur fitness costs for the producing bacteria. Such costs form the basis for models on the co-existence of antibiotic-producing and non-antibiotic producing strains. However, so far studies quantifying the costs of antibiotic production by bacteria are scarce. The current study reports on possible costs, for antibiotic production by Pseudomonas fluorescens Pf0-1, a soil bacterium that is induced to produce a broad-spectrum antibiotic when it is confronted with non-related bacterial competitors or supernatants of their cultures.
METHODOLOGY AND PRINCIPAL FINDINGS
We measured the possible cost of antibiotic production for Pseudomonas fluorescens Pf0-1 by monitoring changes in growth rate with and without induction of antibiotic production by supernatant of a bacterial competitor, namely Pedobacter sp.. Experiments were performed in liquid as well as on semi-solid media under nutrient-limited conditions that are expected to most clearly reveal fitness costs. Our results did not reveal any significant costs for production of antibiotics by Pseudomonas fluorescens Pf0-1. Comparison of growth rates of the antibiotic-producing wild-type cells with those of non-antibiotic producing mutants did not reveal costs of antibiotic production either.
SIGNIFICANCE
Based on our findings we propose that the facultative production of antibiotics might not be selected to mitigate metabolic costs, but instead might be advantageous because it limits the risk of competitors evolving resistance, or even the risk of competitors feeding on the compounds produced.
Topics: Agar; Anti-Bacterial Agents; Culture Techniques; Gene Expression Regulation, Bacterial; Mutation; Pseudomonas fluorescens; Soil Microbiology
PubMed: 22110622
DOI: 10.1371/journal.pone.0027266