| cellular variability of rpos expression underlies subpopulation activation of an integrative and conjugative element. | conjugative transfer of the integrative and conjugative element iceclc in the bacterium pseudomonas knackmussii is the consequence of a bistable decision taken in some 3% of cells in a population during stationary phase. here we study the possible control exerted by the stationary phase sigma factor rpos on the bistability decision. the gene for rpos in p. knackmussii b13 was characterized, and a loss-of-function mutant was produced and complemented. we found that, in absence of rpos, iceclc tra ... | 2012 | 22807690 |
| how can a dual orit system contribute to efficient transfer of an integrative and conjugative element? | integrative and conjugative elements (ices) are particularly interesting model systems for horizontal gene transfer, because they normally reside in an integrated state in the host chromosome but can excise and self-transfer under particular conditions, typically requiring exquisite regulatory cascades. despite important advances in our understanding of the transfer mechanisms of a number of ice, many essential details are lacking. recently we reported that iceclc, a 103 kb ice of pseudomonas kn ... | 2011 | 22016851 |
| factors influencing 4-fluorobenzoate degradation in biofilm cultures of pseudomonas knackmussii b13. | membrane aerated biofilm reactors (mabrs) have potential in wastewater treatment as they permit simultaneous cod minimisation, nitrification and denitrification. here we report on the application of the mabr to the removal of fluorinated xenobiotics from wastewater, employing a pseudomonas knackmussii monoculture to degrade the model compound 4-fluorobenzoate. growth of biofilm in the mabr using the fluorinated compound as the sole carbon source occurred in two distinct phases, with early rapid ... | 2011 | 21536315 |
| a dual functional origin of transfer in the iceclc genomic island of pseudomonas knackmussii b13. | genomic islands (geis) are large dna segments, present in most bacterial genomes, that are most likely acquired via horizontal gene transfer. here, we study the self-transfer system of the integrative and conjugative element iceclc of pseudomonas knackmussii b13, which stands model for a larger group of ice/gei with syntenic core gene organization. functional screening revealed that unlike conjugative plasmids and other ices iceclc carries two separate origins of transfer, with different sequenc ... | 2010 | 21255116 |
| intracellular excision and reintegration dynamics of the iceclc genomic island of pseudomonas knackmussii sp. strain b13. | genomic islands are dna elements acquired by horizontal gene transfer that are common to a large number of bacterial genomes, which can contribute specific adaptive functions, e.g. virulence, metabolic capacities or antibiotic resistances. some genomic islands are still self-transferable and display an intricate life-style, reminiscent of both bacteriophages and conjugative plasmids. here we studied the dynamical process of genomic island excision and intracellular reintegration using the integr ... | 2009 | 19432799 |
| stochasticity and bistability in horizontal transfer control of a genomic island in pseudomonas. | genomic islands (gei) comprise a recently recognized large family of potentially mobile dna elements and play an important role in the rapid differentiation and adaptation of bacteria. most importantly, geis have been implicated in the acquisition of virulence factors, antibiotic resistances or toxic compound metabolism. despite detailed information on coding capacities of geis, little is known about the regulatory decisions in individual cells controlling gei transfer. here, we show how self-tr ... | 2008 | 19098098 |
| pseudomonas panipatensis sp. nov., isolated from an oil-contaminated site. | a gram-negative, motile, rod-shaped, non-sporulating, aerobic bacterial strain (esp-1(t)) was isolated from oil-contaminated soil of panipat oil refinery, india, and its taxonomic position was determined using a polyphasic approach. strain esp-1(t) grew in the presence of 2 % nacl at 30 degrees c and was characterized chemotaxonomically by having c(16 : 0) as the major fatty acid followed by c(17 : 0) cyclo and c(18 : 1)omega7c. phylogenetic analysis based on 16s rrna gene sequences showed that ... | 2008 | 18523175 |
| differences of heterotrophic 13co2 assimilation by pseudomonas knackmussii strain b13 and rhodococcus opacus 1cp and potential impact on biomarker stable isotope probing. | motivated by the finding that pseudomonas knackmussii b13 but not rhodococcus opacus 1cp grows in the absence of externally provided co(2), we investigated the assimilation of (13)co(2) into active cells cultivated with non-labelled glucose as sole energy substrate. (13)c found in the bulk biomass indicated a substantial but different co(2) assimilation by pseudomonas and rhodococcus, respectively (3500 per thousand and 2600 per thousand). cellular fatty acids were labelled from -15 per thousand ... | 2008 | 18341583 |
| pseudomonas knackmussii sp. nov. | the taxonomic position of pseudomonas sp. b13(t), isolated as a 3-chlorobenzoate-degrading organism and used for several groundbreaking studies on the enzymology and genetics of the degradative pathway for haloaromatic compounds, was studied in detail. the previously performed physiological studies, the detection of ubiquinone q-9, the polyamine pattern with putrescine and spermidine as major polyamines, a fatty acid profile with c(18 : 1)omega7c, summed feature 3 and c(16 : 0) as quantitatively ... | 2007 | 17329787 |
| genomic island excisions in bordetella petrii. | among the members of the genus bordetella b. petrii is unique, since it is the only species isolated from the environment, while the pathogenic bordetellae are obligately associated with host organisms. another feature distinguishing b. petrii from the other sequenced bordetellae is the presence of a large number of mobile genetic elements including several large genomic regions with typical characteristics of genomic islands collectively known as integrative and conjugative elements (ices). the ... | 2009 | 19615092 |
| microbial biotransformation of aryl sulfanylpentafluorides. | we report, for the first time, the biotransformation of potential pollutants bearing the pentafluorosulfanyl (sf5-) functional group in a fungus and bacteria. cunninghamella elegans transformed p-methoxy phenyl sf5 via demethylation; pseudomonas knackmussii and p. pseudoalcaligenes kf707 transformed amino-, hydroxyamino- and diamino- substituted phenyl sf5, forming the n-acetylated derivatives as the main product. cell-free extract of streptomyces griseus transformed 4-amino-3-hydroxy-phenyl sf5 ... | 2014 | 23872898 |
| an operon of three transcriptional regulators controls horizontal gene transfer of the integrative and conjugative element iceclc in pseudomonas knackmussii b13. | the integrative and conjugative element iceclc is a mobile genetic element in pseudomonas knackmussii b13, and an experimental model for a widely distributed group of elements in proteobacteria. iceclc is transferred from specialized transfer competent cells, which arise at a frequency of 3-5% in a population at stationary phase. very little is known about the different factors that control the transfer frequency of this ice family. here we report the discovery of a three-gene operon encoded by ... | 2014 | 24945944 |
| the tetr-type mfsr protein of the integrative and conjugative element (ice) iceclc controls both a putative efflux system and initiation of ice transfer. | integrative and conjugating elements (ice) are self-transferable dnas widely present in bacterial genomes, which often carry a variety of auxiliary genes of potential adaptive benefit. one of the model ice is iceclc, an element originally found in pseudomonas knackmussii b13 and known for its propensity to provide its host with the capacity to metabolize chlorocatechols and 2-aminophenol. in this work, we studied the mechanism and target of regulation of mfsr, a tetr-type repressor previously fo ... | 2014 | 25182498 |
| transcriptome analysis of the mobile genome iceclc in pseudomonas knackmussii b13. | integrative and conjugative elements (ice) form a diverse group of dna elements that are integrated in the chromosome of the bacterial host, but can occasionally excise and horizontally transfer to a new host cell. ice come in different families, typically with a conserved core for functions controlling the element's behavior and a variable region providing auxiliary functions to the host. the iceclc element of pseudomonas knackmussii strain b13 is representative for a large family of chromosoma ... | 2010 | 20504315 |
| the missing link: bordetella petrii is endowed with both the metabolic versatility of environmental bacteria and virulence traits of pathogenic bordetellae. | bordetella petrii is the only environmental species hitherto found among the otherwise host-restricted and pathogenic members of the genus bordetella. phylogenetically, it connects the pathogenic bordetellae and environmental bacteria of the genera achromobacter and alcaligenes, which are opportunistic pathogens. b. petrii strains have been isolated from very different environmental niches, including river sediment, polluted soil, marine sponges and a grass root. recently, clinical isolates asso ... | 2008 | 18826580 |
| biodegradation of bisphenol a with diverse microorganisms from river sediment. | the wide distribution of bisphenol a (bpa) in the environment is problematic because of its endocrine-disrupting characteristics and toxicity. developing cost-effective remediation methods for wide implementation is crucial. therefore, this study investigated the bpa biodegradation ability of various microorganisms from river sediment. an acclimated microcosm completely degraded 10 mg l(-1) bpa within 28 h and transformed the contaminant into several metabolic intermediates. during the degradati ... | 2015 | 25590822 |
| improved statistical analysis of low abundance phenomena in bimodal bacterial populations. | accurate detection of subpopulation size determinations in bimodal populations remains problematic yet it represents a powerful way by which cellular heterogeneity under different environmental conditions can be compared. so far, most studies have relied on qualitative descriptions of population distribution patterns, on population-independent descriptors, or on arbitrary placement of thresholds distinguishing biological on from off states. we found that all these methods fall short of accuratel ... | 2013 | 24205184 |
| correction: an operon of three transcriptional regulators controls horizontal gene transfer of the integrative and conjugative element iceclc in pseudomonas knackmussii b13. | | 2015 | 25860840 |
| comparative genome analysis of pseudomonas knackmussii b13, the first bacterium known to degrade chloroaromatic compounds. | pseudomonas knackmussii b13 was the first strain to be isolated in 1974 that could degrade chlorinated aromatic hydrocarbons. this discovery was the prologue for subsequent characterization of numerous bacterial metabolic pathways, for genetic and biochemical studies, and which spurred ideas for pollutant bioremediation. in this study, we determined the complete genome sequence of b13 using next generation sequencing technologies and optical mapping. genome annotation indicated that b13 has a va ... | 2015 | 24803113 |