-
Journal of Bacteriology Jul 1961Colwell, R. R. (University of Washington, Seattle), and J. Liston. Taxonomic relationships among the pseudomonads. J. Bacteriol. 82:1-14. 1961.-An electronic computer...
Colwell, R. R. (University of Washington, Seattle), and J. Liston. Taxonomic relationships among the pseudomonads. J. Bacteriol. 82:1-14. 1961.-An electronic computer technique, utilizing the Adansonian principle that every feature should have equal weight, was applied in an effort to derive a taxonomy of the Pseudomonas-Achromobacter group of gram-negative, asporogenous, rodlike bacteria. The validity of the general method was tested by an analysis of 40 well defined strains, principally derived from type culture collections and representative of different genera and families of the Pseudomonadales and the Eubacteriales. The analysis clearly separated groups which are recognized to be taxonomically distinct. Aerogenic Aeromonas were most similar to the Enterobacteriaceae and taxonomically distinct from the anaerogenic Aeromonas formicans which was more similar to the Pseudomonas group. Oxidative Vibrio species grouped with Pseudomonas and probably should be renamed Pseudomonas. Fermentative Vibrio species showed affinities with A. formicans.Fifty-four Pseudomonas strains out of 58 tested in an analysis of 80 bacterial cultures, clustered into four large groups: group 1, a marine group within which appeared a psychrophilic, nonproteolytic species subgroup related to Vibrio beijerinckii and a subgeneric subgroup which included Pseudomonas elongata; group 2, a subgeneric mesophilic group including Vibrio percolans and associated with Pseudomonas fragi; group 3, a fluorescent pigment-producing group, including three subgroups, a psychrophilic aeruginosa-like species group, a mesophilic Pseudomonas aeruginosa species group, and a heterogeneous subgeneric group containing Vibrio cuneatus and related to Pseudomonas fluorescens and Pseudomonas pavonacea; group 4, a subgeneric nonpigment-producing, mesophilic group, which included Vibrio tyrogenus, Pseudomonas ovalis, and Pseudomonas denitrificans.
Topics: Achromobacter; Aeromonas; Bacteria; Enterobacteriaceae; Oxidation-Reduction; Pseudomonas; Pseudomonas fragi; Pseudomonas putida; Vibrio
PubMed: 13694873
DOI: 10.1128/jb.82.1.1-14.1961 -
Journal of Evolutionary Biology Mar 2014Microbial cells rely on cooperative behaviours that can breakdown as a result of exploitation by cheats. Recent work on cheating in microbes, however, has produced...
Microbial cells rely on cooperative behaviours that can breakdown as a result of exploitation by cheats. Recent work on cheating in microbes, however, has produced examples of populations benefiting from the presence of cheats and/or cooperative behaviours being maintained despite the presence of cheats. These observations have been presented as evidence for selection favouring cheating at the population level. This apparent contradiction arises when cheating is defined simply by the reduced expression of a cooperative trait and not in terms of the social costs and benefits of the trait under investigation. Here, we use two social traits, quorum sensing and iron-scavenging siderophore production in Pseudomonas aeruginosa, to illustrate the importance of defining cheating by the social costs and benefits. We show that whether a strain is a cheat depends on the costs and benefits associated with the social and abiotic environment and not the absolute expression of a cooperative trait.
Topics: Biological Evolution; Oligopeptides; Pseudomonas aeruginosa
PubMed: 24480013
DOI: 10.1111/jeb.12319 -
Journal of Bacteriology Oct 1977Mercury and organomercurial resistance determined by genes on ten Pseudomonas aeruginosa plasmids and one Pseudomonas putida plasmid have been studied with regard to the...
Mercury and organomercurial resistance determined by genes on ten Pseudomonas aeruginosa plasmids and one Pseudomonas putida plasmid have been studied with regard to the range of substrates and the range of inducers. The plasmidless strains were sensitive to growth inhibition by Hg(2+) and did not volatilize Hg(0) from Hg(2+). A strain with plasmid RP1 (which does not confer resistance to Hg(2+)) similarly did not volatilize mercury. All 10 plasmids determine mercury resistance by way of an inducible enzyme system. Hg(2+) was reduced to Hg(0), which is insoluble in water and rapidly volatilizes from the growth medium. Plasmids pMG1, pMG2, R26, R933, R93-1, and pVS1 in P. aeruginosa and MER in P. putida conferred resistance to and the ability to volatilize mercury from Hg(2+), but strains with these plasmids were sensitive to and could not volatilize mercury from the organomercurials methylmercury, ethylmercury, phenylmercury, and thimerosal. These plasmids, in addition, conferred resistance to the organomercurials merbromin, p-hydroxymercuribenzoate, and fluorescein mercuric acetate. The other plasmids, FP2, R38, R3108, and pVS2, determined resistance to and decomposition of a range of organomercurials, including methylmercury, ethylmercury, phenylmercury, and thimerosal. These plasmids also conferred resistance to the organomercurials merbromin, p-hydroxymercuribenzoate, and fluorescein mercuric acetate by a mechanism not involving degradation. In all cases, organomercurial decomposition and mercury volatilization were induced by exposure to Hg(2+) or organomercurials. The plasmids differed in the relative efficacy of inducers. Hg(2+) resistance with strains that are organomercurial sensitive appeared to be induced preferentially by Hg(2+) and only poorly by organomercurials to which the cells are sensitive. However, the organomercurials p-hydroxymercuribenzoate, merbromin, and fluorescein mercuric acetate were strong gratuitous inducers but not substrates for the Hg(2+) volatilization system. With strains resistant to phenylmercury and thimerosal, these organomercurials were both inducers and substrates.
Topics: Chemical Phenomena; Chemistry; Drug Resistance, Microbial; Genes; Mercury; Organomercury Compounds; Plasmids; Pseudomonas; Pseudomonas aeruginosa; R Factors; Volatilization
PubMed: 410779
DOI: 10.1128/jb.132.1.186-196.1977 -
Food Microbiology Aug 2018Microbiological, chemical and physical parameters of minimally processed red chicory (Cichorium intybus L.) subjected to two different transformation processes were...
Microbiological, chemical and physical parameters of minimally processed red chicory (Cichorium intybus L.) subjected to two different transformation processes were investigated. A classic ready-to-eat (RTE) process (P1) and a production without cutting (P2) were monitored during refrigerated (4 °C) storage (15 d). Total mesophilic microorganisms, total psychrotrophic microorganisms and pseudomonads were detected at the highest cell densities in all samples. Presumptive Pseudomonas population dominated the cultivable microbial community of RTE red chicory and were characterized genetically. Twenty-two randomly amplified polymorphic DNA (RAPD) types were investigated by 16S rRNA gene sequencing, resulting in members of Rahnella and Pseudomonas. The identification of Pseudomonas species was further determined by sequencing of gyrB, rpoB and rpoD genes resulting in 16 species. A highest visual quality and a lower weight loss and colour variation were registered for P2, while soluble solid, nitrate and ascorbic acid contents were not affected by processing and storage. The integrated microbiological, chemical and physical approach applied in this study demonstrated the longer shelf-life of P2 red chicory.
Topics: Cichorium intybus; Food Storage; Pseudomonas; Random Amplified Polymorphic DNA Technique; Vegetables
PubMed: 29526216
DOI: 10.1016/j.fm.2018.02.008 -
Microbial Genomics Jul 2021is a highly diverse genus that includes species that cause disease in both plants and animals. Recently, pathogenic pseudomonads from the and species complexes have...
is a highly diverse genus that includes species that cause disease in both plants and animals. Recently, pathogenic pseudomonads from the and species complexes have caused significant outbreaks in several agronomically important crops in Turkey, including tomato, citrus, artichoke and melon. We characterized 169 pathogenic strains associated with recent outbreaks in Turkey via multilocus sequence analysis and whole-genome sequencing, then used comparative and evolutionary genomics to characterize putative virulence mechanisms. Most of the isolates are closely related to other plant pathogens distributed among the primary phylogroups of , although there are significant numbers of isolates, which is a species better known as a rhizosphere-inhabiting plant-growth promoter. We found that all 39 citrus blast pathogens cluster in phylogroup 2, although strains isolated from the same host do not cluster monophyletically, with lemon, mandarin orange and sweet orange isolates all being intermixed throughout the phylogroup. In contrast, 20 tomato pith pathogens are found in two independent lineages: one in the secondary phylogroups, and the other from the species complex. These divergent pith necrosis strains lack characteristic virulence factors like the canonical tripartite type III secretion system, large effector repertoires and the ability to synthesize multiple bacterial phytotoxins, suggesting they have alternative molecular mechanisms to cause disease. These findings highlight the complex nature of host specificity among plant pathogenic pseudomonads.
Topics: Crops, Agricultural; Genome, Bacterial; Multilocus Sequence Typing; Plant Diseases; Plants; Pseudomonas fluorescens; Pseudomonas syringae; Turkey; Type III Secretion Systems; Virulence Factors; Whole Genome Sequencing
PubMed: 34227931
DOI: 10.1099/mgen.0.000585 -
Applied and Environmental Microbiology May 2016Microbial biofilms and mineral precipitation commonly co-occur in engineered water systems, such as cooling towers and water purification systems, and both decrease...
Microbial biofilms and mineral precipitation commonly co-occur in engineered water systems, such as cooling towers and water purification systems, and both decrease process performance. Microbial biofilms are extremely challenging to control and eradicate. We previously showed that in situ biomineralization and the precipitation and deposition of abiotic particles occur simultaneously in biofilms under oversaturated conditions. Both processes could potentially alter the essential properties of biofilms, including susceptibility to biocides. However, the specific interactions between mineral formation and biofilm processes remain poorly understood. Here we show that the susceptibility of biofilms to chlorination depends specifically on internal transport processes mediated by biomineralization and the accumulation of abiotic mineral deposits. Using injections of the fluorescent tracer Cy5, we show that Pseudomonas aeruginosa biofilms are more permeable to solutes after in situ calcite biomineralization and are less permeable after the deposition of abiotically precipitated calcite particles. We further show that biofilms are more susceptible to chlorine killing after biomineralization and less susceptible after particle deposition. Based on these observations, we found a strong correlation between enhanced solute transport and chlorine killing in biofilms, indicating that biomineralization and particle deposition regulate biofilm susceptibility by altering biocide penetration into the biofilm. The distinct effects of in situ biomineralization and particle deposition on biocide killing highlight the importance of understanding the mechanisms and patterns of biomineralization and scale formation to achieve successful biofilm control.
Topics: Biofilms; Chlorine; Disinfectants; Microbial Viability; Minerals; Pseudomonas aeruginosa
PubMed: 26944848
DOI: 10.1128/AEM.03954-15 -
Biofouling Feb 2017Quorum sensing plays a pivotal role in Pseudomonas aeruginosa's virulence. This paper reviews experimental results on antimicrobial strategies based on quorum sensing...
Quorum sensing plays a pivotal role in Pseudomonas aeruginosa's virulence. This paper reviews experimental results on antimicrobial strategies based on quorum sensing inhibition and discusses current targets in the regulatory network that determines P. aeruginosa biofilm formation and virulence. A bioinformatics framework combining literature mining with information from biomedical ontologies and curated databases was used to create a knowledge network of potential anti-quorum sensing agents for P. aeruginosa. A total of 110 scientific articles, corresponding to 1,004 annotations, were so far included in the network and are analysed in this work. Information on the most studied agents, QS targets and methods is detailed. This knowledge network offers a unique view of existing strategies for quorum sensing inhibition and their main regulatory targets and may be used to readily access otherwise scattered information and to help generate new testable hypotheses. This knowledge network is publicly available at http://pcquorum.org/ .
Topics: Anti-Bacterial Agents; Biofilms; Computational Biology; Pseudomonas aeruginosa; Quorum Sensing; Virulence; Virulence Factors
PubMed: 28121162
DOI: 10.1080/08927014.2016.1272104 -
Applied and Environmental Microbiology Jan 2006The genus Pseudomonas (sensu stricto) represents a group of microorganisms directly involved in functions conferring plant health. We performed a study in the DOK...
The genus Pseudomonas (sensu stricto) represents a group of microorganisms directly involved in functions conferring plant health. We performed a study in the DOK long-term agricultural field experiment on the basis of previously published Pseudomonas-selective PCR primers in order to investigate the community structure of the microbial groups defined by the target range of these primers. Three different agricultural management systems, i.e., conventional, biodynamic, and bio-organic, along with mineral and unfertilized controls were investigated, with each system planted with either winter wheat or a grass-clover ley. Amplified small-subunit rRNA gene fragments were analyzed using the genetic profiling techniques restriction fragment length polymorphism (RFLP) and denaturing gradient gel electrophoresis (DGGE), revealing distinct differences between soils planted with winter wheat and grass clover but only minor differences between the management systems. Phylogenetic analyses of 59 clone sequences retrieved from bio-organic and unfertilized systems identified sequences related to Pseudomonas fluorescens and a novel cluster termed Cellvibrio-related Pseudomonadaceae (CRP). The CRP clones were exclusively isolated from winter wheat soil samples and were responsible for the crop-specific differences observed in RFLP and DGGE profiles. New primers were designed for the amplification of CRP targets directly from soil DNA, yielding strong signals exclusively for winter wheat soils. We concluded that crop-associated CRP exist in agricultural soils and that genetic profiling followed by specific probe design represents a valuable approach for identification as well as sensitive and rapid monitoring of novel microbial groups in the environment.
Topics: Agriculture; Cellvibrio; DNA Primers; Ecosystem; Electrophoresis; Genes, rRNA; Medicago; Molecular Sequence Data; Phylogeny; Polymorphism, Restriction Fragment Length; Pseudomonadaceae; Pseudomonas fluorescens; Seasons; Sequence Analysis, DNA; Soil Microbiology; Time Factors; Triticum
PubMed: 16391022
DOI: 10.1128/AEM.72.1.37-43.2006 -
Biochimica Et Biophysica Acta.... Dec 2019In recent years, hopanoids, a group of pentacyclic compounds found in bacterial membranes, are in the spotlight since it was proposed that they induce order in lipid...
In recent years, hopanoids, a group of pentacyclic compounds found in bacterial membranes, are in the spotlight since it was proposed that they induce order in lipid membranes in a similar way cholesterol do in eukaryotes, despite their structural differences. We studied here whether diplopterol (an abundant hopanoid) promoted similar effects on model membranes as sterols do. We analyzed the compaction, dynamics, phase segregation, permeability and compressibility of model membranes containing diplopterol, and compared with those containing sterols from animals, plants and fungi. We also tested the effect that the incubation with diplopterol had on hopanoid-lacking bacteria. Our results show that diplopterol induces phase segregation, increases lipid compaction, and decreases permeability on phospholipid membranes, while retaining membrane fluidity and compressibility. Furthermore, the exposition to this hopanoid decreases the permeability of the opportunistic pathogen Pseudomonas aeruginosa and increases the resistance to antibiotics. All effects promoted by diplopterol were similar to those generated by the sterols. Our observations add information on the functional significance of hopanoids as molecules that play an important role in membrane organization and dynamics in model membranes and in a bacterial system.
Topics: Cell Membrane; Cell Membrane Permeability; Lipid Bilayers; Membrane Lipids; Membranes; Models, Biological; Permeability; Phospholipids; Pseudomonadaceae; Sterols; Triterpenes
PubMed: 31499020
DOI: 10.1016/j.bbamem.2019.183060 -
International Journal of Environmental... Feb 2011Pseudomonas aeruginosa is an important opportunistic pathogen in recreational waters and the primary cause of hot tub folliculitis and otitis externa. The aim of this...
Pseudomonas aeruginosa is an important opportunistic pathogen in recreational waters and the primary cause of hot tub folliculitis and otitis externa. The aim of this surveillance study was to determine the background prevalence and antimicrobial resistance profile of P. aeruginosa in swimming pools and hot tubs. A convenience sample of 108 samples was obtained from three hot tubs and eight indoor swimming pools. Water and swab samples were processed using membrane filtration, followed by confirmation with polymerase chain reaction. Twenty-three samples (21%) were positive for P. aeruginosa, and 23 isolates underwent susceptibility testing using the microdilution method. Resistance was noted to several antibiotic agents, including amikacin (intermediate), aztreonam, ceftriaxone, gentamicin, imipenem, meropenem (intermediate), ticarcillin/clavulanic acid, tobramycin (intermediate), and trimethoprim/sulfamethoxazole. The results of this surveillance study indicate that 96% of P. aeruginosa isolates tested from swimming pools and hot tubs were multidrug resistant. These results may have important implications for cystic fibrosis patients and other immune-suppressed individuals, for whom infection with multidrug-resistant P. aeruginosa would have greater impact. Our results underlie the importance of rigorous facility maintenance, and provide prevalence data on the occurrence of antimicrobial resistant strains of this important recreational water-associated and nosocomial pathogen.
Topics: Drug Resistance, Multiple, Bacterial; Hot Temperature; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Swimming Pools
PubMed: 21556203
DOI: 10.3390/ijerph8020554