Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| genetic and biochemical characterization of a 2-pyrone-4, 6-dicarboxylic acid hydrolase involved in the protocatechuate 4, 5-cleavage pathway of sphingomonas paucimobilis syk-6. | sphingomonas paucimobilis syk-6 is able to grow on a wide variety of dimeric lignin compounds with guaiacyl moieties, which are converted into protocatechuate by the actions of lignin degradation enzymes in this strain. protocatechuate is a key metabolite in the syk-6 degradation of lignin compounds with guaiacyl moieties, and it is thought that it degrades to pyruvate and oxaloacetate via the protocatechuate 4,5-cleavage pathway. in a 10.5-kb ecori fragment carrying the protocatechuate 4,5-diox ... | 1999 | 9864312 |
| bacterial filament formation, a defense mechanism against flagellate grazing, is growth rate controlled in bacteria of different phyla. | a facultatively filamentous bacterium was isolated from eutrophic lake water and was identified as flectobacillus sp. strain mwh38 (a member of the cytophaga-flavobacterium-bacteroides phylum) by comparative 16s rrna gene sequence analysis. filament formation by flectobacillus sp. strain mwh38 and filament formation by flectobacillus major, the closest known relative of strain mwh38, were studied in chemostat cultures under grazing pressure by the bacterivorous flagellate ochromonas sp. strain d ... | 1999 | 9872755 |
| purification and properties of culture-broth-secreted esterase from the polyurethane degrader comamonas acidovorans tb-35. | the polyester-polyurethane (pur)-degrading bacterium comamonas acidovorans tb-35 produces two kinds of esterases, one cell-bound esterase (pur esterase) and the other secreted in the culture broth (cbs esterase). in this study, the cbs esterase and the two recombinant esterases were purified. identification of the physical and biochemical properties of the cbs and pur esterases revealed that they have the same polypeptide from one gene. this finding was supported by the observation that escheric ... | 1999 | 16232649 |
| bioaugmentation of activated sludge by an indigenous 3-chloroaniline-degrading comamonas testosteroni strain, i2gfp. | a strain identified as comamonas testosteroni i2 was isolated from activated sludge and found to be able to mineralize 3-chloroaniline (3-ca). during the mineralization, a yellow intermediate accumulated temporarily, due to the distal meta-cleavage of chlorocatechol. this strain was tested for its ability to clean wastewater containing 3-ca upon inoculation into activated sludge. to monitor its survival, the strain was chromosomally marked with the gfp gene and designated i2gfp. after inoculatio ... | 2000 | 10877785 |
| arrangement and regulation of the genes for meta-pathway enzymes required for degradation of phenol in comamonas testosteroni ta441. | comamonas testosteroni ta441 degrades phenol by a meta-cleavage pathway after the occurrence of a spontaneous mutation that derepresses the aphklmnopqb operon encoding phenol hydroxylase and catechol 2,3-dioxygenase, the enzymes for the initial two steps of the degradation pathway. a gene cluster, aphcefghji, encoding the meta-pathway enzymes for degradation of 2-hydroxymuconic semialdehyde (hms) to tca cycle intermediates was found downstream of the aphk operon. the upstream operon and the down ... | 2000 | 10878134 |
| steroid-inducible transcription of the 3beta/17beta-hydroxysteroid dehydrogenase gene (3beta/17beta-hsd) in comamonas testosteroni. | the expression of the comamonas testosteroni gene, encoding 3beta/17beta-hydroxysteroid dehydrogenase enzyme (3beta/17beta-hsd), was analyzed at the transcriptional level. northern blot analysis detected a 1 kb transcript in bacterial cells grown in minimum media supplemented with casamino acids and testosterone. also this transcript was observed when cells were grown in presence of 1-dehydrotestosterone, androstenedione and 1,4-androstadien-3, 17dione, but not in presence of acetate, citrate, c ... | 2000 | 10925214 |
| crystal structure of omp32, the anion-selective porin from comamonas acidovorans, in complex with a periplasmic peptide at 2.1 a resolution. | porins provide diffusion channels for salts and small organic molecules in the outer membrane of bacteria. in ompf from escherichia coli and related porins, an electrostatic field across the channel and a potential, originating from a surplus of negative charges, create moderate cation selectivity. here, we investigate the strongly anion-selective porin omp32 from comamonas acidovorans, which is closely homologous to the porins of pathogenic bordetella and neisseria species. | 2000 | 10986465 |
| the crystal structure of 3alpha -hydroxysteroid dehydrogenase/carbonyl reductase from comamonas testosteroni shows a novel oligomerization pattern within the short chain dehydrogenase/reductase family. | the crystal structure of 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase from comamonas testosteroni (3alpha-hsdh) as well as the structure of its binary complex with nad(+) have been solved at 1.68-a and 1.95-a resolution, respectively. the enzyme is a member of the short chain dehydrogenase/reductase (sdr) family. accordingly, the active center and the conformation of the bound nucleotide cofactor closely resemble those of other sdrs. the crystal structure reveals one homodimer per asym ... | 2000 | 11007791 |
| development of a vital fluorescent staining method for monitoring bacterial transport in subsurface environments. | previous bacterial transport studies have utilized fluorophores which have been shown to adversely affect the physiology of stained cells. this research was undertaken to identify alternative fluorescent stains that do not adversely affect the transport or viability of bacteria. initial work was performed with a groundwater isolate, comamonas sp. strain da001. potential compounds were first screened to determine staining efficiencies and adverse side effects. 5-(and 6-)-carboxyfluorescein diacet ... | 2000 | 11010903 |
| equilibrium and kinetic analysis of folding of ketosteroid isomerase from comamonas testosteroni. | equilibrium and kinetic analyses have been carried out to elucidate the folding mechanism of homodimeric ketosteroid isomerase (ksi) from comamonas testosteroni. the folding of ksi was reversible since the activity as well as the fluorescence and cd spectra was almost completely recovered after refolding. the equilibrium unfolding transitions monitored by fluorescence and cd measurements were almost coincident with each other, and the transition midpoint increased with increasing protein concent ... | 2000 | 11041875 |
| expression, two-dimensional crystallization, and three-dimensional reconstruction of the beta8 outer membrane protein omp21 from comamonas acidovorans. | the omp21 protein from the proteobacterium comamonas (delftia) acidovorans belongs to the recently described beta8 family of outer membrane proteins, characterized by eight antiparallel beta-strands which form a beta-barrel. this family includes virulence proteins, ompa and ompx from escherichia coli, and other related molecules. after we established an expression system, recombinant omp21 was purified by ni(2+) chelation affinity chromatography and refolded in situ while bound to resin. the nat ... | 2000 | 11042080 |
| monitoring bacterial transport by stable isotope enrichment of cells. | understanding the transport and behavior of bacteria in the environment has broad implications in diverse areas, ranging from agriculture to groundwater quality, risk assessment, and bioremediation. the ability to reliably track and enumerate specific bacterial populations in the context of native communities and environments is key to developing this understanding. we report a novel bacterial tracking approach, based on altering the stable carbon isotope value (delta(13)c) of bacterial cells, w ... | 2000 | 11055946 |
| role of catalytic residues in enzymatic mechanisms of homologous ketosteroid isomerases. | ketosteroid isomerase (ksi) is one of the most proficient enzymes catalyzing an allylic isomerization reaction at a diffusion-controlled rate. in this study of ksi, we have detailed the structures of its active site, the role of various catalytic residues, and have explained the origin of the its fast reactivity by carrying out a detailed investigation of the enzymatic reaction mechanism. this investigation included the x-ray determination of 15 crystal structures of two homologous enzymes in fr ... | 2000 | 11076530 |
| [sterilization of phacoemulsification and vitrectomy instruments. contamination and evaluation]. | contamination of automated surgical equipment is widely disregarded as a potential source of perioperative infection. we investigated the possibility of contamination of the aspiration fluid by the vacuum control manifold (vcm). the normal, unsterile internal vcm was compared with a modified external vcm that was regularly disinfected. | 2000 | 11105548 |
| characterization of fungal 17beta-hydroxysteroid dehydrogenases. | to promote understanding of the evolution of the steroid hormone signalling and hydroxysteroid dehydrogenases (hsds), comparative characterization of fungal 17beta-hsds was performed. constitutive 17beta-hsd activity was determined in cytosols of the fungi: cochliobolus lunatus, pleospora herbarum, fusarium lini, trichoderma viride, mucor spinosus, rhizopus nigricans and pleurotus ostreatus. the reaction equilibrium in all species except p. ostreatus was shifted towards reduction. the preferenti ... | 2000 | 11126752 |
| polymicrobial tenosynovitis with pasteurella multocida and other gram negative bacilli after a siberian tiger bite. | mammalian bites present a considerable clinical problem because they are often associated with bacterial infections. pasteurella multocida is a microorganism that commonly infects both canine and small feline bites. zoonotic infections developing after large feline bites have been recognised, although their reports are limited. we describe a 35 year old man who was bitten by a siberian tiger and who developed infectious tenosynovitis secondary to p multocida, bergeyella (weeksella) zoohelcum, an ... | 2000 | 11127273 |
| evaluation of autoscan-w/a and the vitek gni+ automicrobic system for identification of non-glucose-fermenting gram-negative bacilli. | the autoscan-w/a (w/a; dade behring microscan inc., west sacramento, calif.) and vitek automicrobic system (vitek ams; biomérieux vitek systems, inc., hazelwood, mo.) are both fully automated microbiology systems. we evaluated the accuracy of these two systems in identifying nonglucose-fermenting gram-negative bacilli. we used the w/a with conventional-panel neg combo type 12 and vitek gni+ identification systems. a total of 301 isolates from 25 different species were tested. of these, 299 isola ... | 2000 | 10699007 |
| catalytic activity of the d38a mutant of 3-oxo-delta 5-steroid isomerase: recruitment of aspartate-99 as the base. | 3-oxo-delta(5)-steroid isomerase (ksi) from comamonas (pseudomonas) testosteroni catalyzes the isomerization of beta,gamma-unsaturated 3-oxosteroids to their conjugated isomers through an intermediate dienolate. residue asp-38 (pk(a) 4.57) acts as a base to abstract a proton from c-4 of the substrate to form an intermediate dienolate, which is then reprotonated on c-6. both tyr-14 (pk(a) 11.6) and asp-99 (pk(a) >/= 9.5) function as hydrogen-bond donors to o-3 of the steroid, helping to stabilize ... | 2000 | 10727228 |
| automated surgical equipment requires routine disinfection of vacuum control manifold to prevent postoperative endophthalmitis. | contamination of automated surgical equipment is a potential source of postoperative endophthalmitis. the effect of disinfecting the unsterile vacuum control manifold (vcm) on contamination of the aspiration fluid was studied. | 2000 | 10768329 |
| steady-state kinetic characterization and crystallization of a polychlorinated biphenyl-transforming dioxygenase. | the oxygenase component of biphenyl dioxygenase (bpdo) from comamonas testosteroni b-356 dihydroxylates biphenyl and some polychlorinated biphenyls (pcbs), thereby initiating their degradation. overexpressed, anaerobically purified bpdo had a specific activity of 4.9 units/mg, and its oxygenase component appeared to contain a full complement of fe(2)s(2) center and catalytic iron. oxygenase crystals in space group r3 were obtained under anaerobic conditions using polyethylene glycol as the preci ... | 2000 | 10777527 |
| factors affecting the freeze-fracture morphology of in vivo polyhydroxyalkanoate granules. | interesting morphologies were observed when comamonas acidovorans containing polyhydroxyalkanoates (pha) of various compositions was freeze-fractured at temperatures far below the glass transition temperatures of pha. in vivo granules of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) comparatively showed the most ductility, and could be stretched extensively. contrary to the uniform needle-type deformation shown by the poly(3-hydroxybutyrate) homopolymer when fractured at -110 degrees c, copolymer ... | 2000 | 10779866 |
| [physico-chemical and microbiological characteristics of groundwater from observation boreholes of a deep radioactive liquid waste repository]. | a radioactive liquid waste repository was found to be a habitat of the rich microbial community with a high catabolic potential. groundwater from a depth of 162-189 m contained aerobic saprotrophic and anaerobic fermentative, sulfate-reducing, and denitrifying bacteria. nitrate-reducing bacteria residing in this groundwater were isolated in pure cultures. based on the results of their physiological studies, 16s rrna sequencing, and phylogenetic analysis, the microorganisms isolated were ascribed ... | 2000 | 10808497 |
| active site residues of cis-2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase from comamonas testosteroni strain b-356. | cis-2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase (bphb) from comamonas testosteroni strain b-356 is the second enzyme of the biphenyl/polychlorinated biphenyl degradation pathway. based on the crystal structure of a related bphb, three conserved residues, ser142, tyr155, and lys159, have been suggested to function as a "catalytic triad" as for other members of the short-chain alcohol dehydrogenase/reductase (sdr) family. in this study, substitution of each triad residue was examined in bphb. ... | 2000 | 10819967 |
| aerobic denitrifiers isolated from diverse natural and managed ecosystems. | twenty-eight bacterial strains were isolated from an ecosystem adapted to fluctuating oxic-anoxic conditions. this ecosystem comprised a mixture of different natural and wastewater treatment environments. among the 28 strains isolated, 10 exhibited aerobic denitrifying activity, i.e., co-respiration of oxygen and nitrate and simultaneous production of nitrite by 4 of them and of nitrogen gas by the remaining 6. comparisons between the 16s rdna sequences of the 10 strains showed that 3 of them we ... | 2000 | 10833227 |
| functional expression, purification, and characterization of 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase from comamonas testosteroni. | 3alpha-hydroxysteroid dehydrogenase (3alpha-hsd) catalyzes the oxidoreduction at carbon 3 of steroid hormones and is postulated to initiate the complete mineralization of the steroid nucleus to co(2) and h(2)o in comamonas testosteroni. by this activity, 3alpha-hsd provides the basis for c. testosteroni to grow on steroids as sole carbon and energy source. 3alpha-hsd was cloned and overexpressed in e. coli and purified to homogeneity by an affinity chromatography system as his-tagged protein. th ... | 2000 | 10833462 |
| dihexyl sulfosuccinate biodegradation by mixed cultures. | the primary biodegradation of dihexyl sulfosuccinate has been demonstrated using two single cultures and three mixed bacterial cultures of comamonas terrigena. primary biodegradation was found in all variants. the highest biotransformation rate and efficiency was observed in one of the single strains. no synergistic effect on degradation was found in mixed cultures. | 2000 | 11501412 |
| effect of starvation and chloramphenicol on acceleration of bacterial dihexyl sulfosuccinate biotransformation. | starvation for carbon and energy sources accelerated the biotransformation of the anion-active surfactant dihexyl sulfosuccinate (dhs) by comamonas terrigena cells. chloramphenicol (cm) added at different time intervals to non-starved cells inhibited the dhs transformation. the largest difference between cells treated and non-treated by cm was observed for a 16-h-starvation period. protein synthesis de novo during starvation enhanced the dhs biotransformation efficiency. a partial transformation ... | 2000 | 11501413 |
| humus bacteria of norway spruce stands: plant growth promoting properties and birch, red fescue and alder colonizing capacity. | we studied the potential of the humus layer of the norway spruce stands to supply beneficial rhizobacteria to birch (betula pendula), alder (alnus incana) and fescue grass (festuca rubra), representatives of pioneer vegetation after clear-cutting of the coniferous forest. axenically grown seedlings of these species were inoculated with the acid spruce humus, ph 3.7-5.3. actinorhizal propagules, capable of nodulating alder, were present in high density (10(3) g(-1)) in humus of long-term limed pl ... | 2000 | 10640667 |
| binding of 2-naphthols to d38e mutants of 3-oxo-delta 5-steroid isomerase: variation of ligand ionization state with the nature of the electrophilic component. | 3-oxo-delta(5)-steroid isomerase (ksi) catalyzes the isomerization of a variety of 3-oxo-delta(5)-steroids to their conjugated delta(4) isomers. the mechanism involves sequential enolization and ketonization, with asp-38 acting to transfer a proton from c-4 to c-6 through a dienol(ate) intermediate. we have previously proposed that this intermediate is anionic, with stabilization provided from direct hydrogen bonding from tyr-14 and asp-99 to the oxygen of the steroid. in this work, we analyze t ... | 2000 | 10625485 |
| polychlorinated biphenyl degradation activities and hybridization analyses of fifteen aerobic strains isolated from a pcb-contaminated site. | fifteen bacterial strains using biphenyl as sole carbon and energy source, obtained from different positions and depths of a polychlorinated biphenyl (pcb)-contaminated area, were analyzed for their basic metabolic phenotypes and subjected to genomic dna hybridization screening for the presence of well characterized bph operons such as those of pseudomonas pseudoalcaligenes kf707 and rhodococcus globerulus p6. most of the isolates belonged to the gamma-subdivision (pseudomonas stutzeri, p. pluti ... | 2001 | 11501677 |
| potential application of catalase-peroxidase from comamonas terrigena n3h in the biodegradation of phenolic compounds. | comamonas terrigena n3h is a gram-negative rod-shaped bacterium that was isolated from contaminated soil in slovakia. this bacterium showed remarkable biodegradation properties. we investigated the expression and functioning of two catalase isozymes in this bacterium. the typical catalase could be induced by cadmium ions, whereas the catalase-peroxidase enzyme was constitutively expressed. since c. terrigena lacks the key enzyme for complete degradation of phenols (phenolhydroxylase), we analyse ... | 2001 | 11519996 |
| central venous catheter-related infection due to comamonas testosteroni in a woman with breast cancer. | a 75-y-old woman with breast cancer presented with bacteremia due to comamonas testosteroni. evolution was favorable following adapted antimicrobial therapy and removal of a central venous catheter. this germ seems to be a rare pathogen; as reported in the literature, it is mostly encountered in patients with predisposing factors. | 2001 | 11525361 |
| investigation of atrazine metabolism in river sediment by high-performance liquid chromatography/mass spectrometry. | microbial degradation processes play an important role in chemical water clearance taking place in river sediments. bacteria remove not only easily degradable organic species, but various xenobiotics as well, producing clear and xenobiotic free water for bank-filtered wells. atrazine is a widely used herbicide, and it is one of the most common xenobiotics present in danube water. in this study the pathway and kinetics of atrazine metabolism of sedimental microbiota were studied. samples were col ... | 2001 | 11555874 |
| evidence for detachment of indigenous bacteria from aquifer sediment in response to arrival of injected bacteria. | two bacterial strains isolated from the aquifer underlying oyster, va., were recently injected into the aquifer and monitored using ferrographic capture, a high-resolution immunomagnetic technique. injected cells were enumerated on the basis of a vital fluorescence stain, whereas total cell numbers (stained target cells plus unstained target and antigenically similar indigenous bacteria) were identified by cell outlines emanating from fluorophore-conjugated antibodies to the two target strains. ... | 2001 | 11571201 |
| physiological and genetic characteristics of two bacterial strains utilizing phenoxypropionate and phenoxyacetate herbicides. | two strains, rhodoferax sp. p230 and delftia (comamonas) acidovorans mci, have previously been shown to carry activities for the degradation of the two enantiomers of (rs)-2-(2,4-dichlorophenoxy-)propionate (dichlorprop) and (rs)-2-(4-chloro-2-methylphenoxy-)propionate (mecoprop) and, in addition, are capable of degrading phenoxyacetate derivatives 2.4-dichlorophenoxyacetate (2,4-d) and 4-chloro-2-methylphenoxyacetate (mcpa). metabolism of the herbicides is initiated by alpha-ketoglutarate-depen ... | 2001 | 11572451 |
| xenophilus azovorans gen. nov., sp. nov., a soil bacterium that is able to degrade azo dyes of the orange ii type. | the taxonomy of strain kf46ft, which was isolated previously after an aerobic enrichment with the azo compound 1-(4'-carboxyphenylazo)-2-naphthol as the sole source of energy and carbon, was investigated by a polyphasic approach. the organism contained a quinone system with ubiquinone q-8 and 2-hydroxyputrescine and putrescine as the major polyamines, suggesting that strain kf46ft belonged to the beta-subclass of the proteobacteria. the polar lipid profile consisted mainly of phosphatidylethanol ... | 2001 | 11594616 |
| crystallization of quinohaemoprotein alcohol dehydrogenase from comamonas testosteroni: crystals with unique optical properties. | quinohaemoprotein alcohol dehydrogenase from comamonas testosteroni is a functional electron-transfer protein containing both a haem c and a pyrroloquinoline quinone cofactor. the enzyme has been crystallized at 277 k using polyethylene glycol 6000 as precipitant. the crystals belong to space group c2, with unit-cell parameters a = 98.1, b = 74.3, c = 92.2 a, beta = 105.9 degrees. a native data set with a resolution of 2.44 a resolution has been collected. the approximate orientation of the haem ... | 2001 | 11679760 |
| cellular fatty acid composition of lautropia mirabilis. | ten strains of lautropia mirabilis (atcc 51599(t) and nine phenotypically similar clinical isolates) were examined for cellular fatty acid (cfa) composition to evaluate their chemical relatedness to known bacterial species and groups. the cfas were liberated from whole cells by base hydrolysis, methylated, and analyzed by gas-liquid chromatography. cfa profiles were generated by using a commericial software package (midi, newark, del.). all strains tested had an identical cfa profile characteriz ... | 2001 | 11682548 |
| rubrobacter-related bacteria associated with rosy discolouration of masonry and lime wall paintings. | a molecular approach was chosen to analyse the correlation between bacterial colonisation and rosy discolouration of masonry and lime wall paintings of two historically important buildings in austria and germany. the applied molecular method included pcr amplification of genes encoding the small subunit rrna of bacteria (16s rdna), genetic fingerprinting by denaturing gradient gel electrophoresis (dgge), construction of 16s rdna clone libraries, and comparative phylogenetic sequence analyses. th ... | 2001 | 11702076 |
| analysis of bacterial communities in the rhizosphere of chrysanthemum via denaturing gradient gel electrophoresis of pcr-amplified 16s rrna as well as dna fragments coding for 16s rrna. | the effect of developing chrysanthemum roots on the presence and activity of bacterial populations in the rhizosphere was examined by using culture-independent methods. nucleic acids were extracted from rhizosphere soil samples associated with the bases of roots or root tips of plants harvested at different stages of development. pcr and reverse transcriptase (rt) pcr were used to amplify 16s ribosomal dna (rdna) and 16s rrna, respectively, and the products were subjected to denaturing gradient ... | 2001 | 11133442 |
| regulation of the steroid-inducible 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase gene in comamonas testosteroni. | the comamonas testosteroni 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase gene (hsda) codes for an adaptive enzyme in the degradation of steroid compounds. however, no information was available on the molecular regulation of steroid-inducible genes nor on the mechanism of steroid signaling in procaryotes. we, therefore, investigated the cis- and trans-acting elements of hsda expression to infer the mechanism of its molecular regulation by steroids. the gene was localized on a 5.257-kilob ... | 2001 | 11139589 |
| crystallization and preliminary x-ray analysis of a gamma-lactamase. | an enzyme from comomonas acidovorans has been isolated that is specific for the stereospecific hydrolysis of (+)gamma-lactam. this so-called (+)gamma-lactamase has important applications in biotransformation reactions. the enzyme has been crystallized by vapour-phase diffusion using polyethylene glycol 4000 as a precipitant. addition of a detergent, beta-octylglucoside, was found to be essential for obtaining diffraction-quality crystals. the crystals grow in the space group p1, with unit-cell p ... | 2001 | 11173481 |
| comamonas acidovorans keratitis in a hydrogel contact lens wearer. | to present an unusual case of keratitis in a patient who wears hydrogel contact lenses that are replaced on a monthly basis. the agent isolated was comamonas acidovorans, a species of pseudomonas. | 2001 | 11215608 |
| genetic diversity among 3-chloroaniline- and aniline-degrading strains of the comamonadaceae. | we examined the diversity of the plasmids and of the gene tdnq, involved in the oxidative deamination of aniline, in five bacterial strains that are able to metabolize both aniline and 3-chloroaniline (3-ca). three strains have been described and identified previously, i.e., comamonas testosteroni i2 and delftia acidovorans ca28 and bn3.1. strains lme1 and b8c were isolated in this study from linuron-treated soil and from a wastewater treatment plant, respectively, and were both identified as d. ... | 2001 | 11229899 |
| an inducible 1-butanol dehydrogenase, a quinohaemoprotein, is involved in the oxidation of butane by "pseudomonas butanovora". | butane-grown "pseudomonas butanovora" expressed two soluble alcohol dehydrogenases (adhs), an nad(+)-dependent secondary adh and an nad(+)-independent primary adh. two additional nad(+)-dependent secondary adhs could be detected when cells were grown on 2-butanol and lactate. the inducible nad(+)-independent 1-butanol dehydrogenase (bdh) of butane-grown cells was primarily responsible for 1-butanol oxidation in the butane metabolism pathway. bdh was purified to near homogeneity and identified as ... | 2001 | 11238982 |
| utility of high performance liquid chromatography/electrospray/mass spectrometry of polar lipids in specifically per-13c labeled gram-negative bacteria da001 as a tracer for acceleration of bioremediation in the subsurface. | specific fatty acids from phosphatidylglycerol (pg) and phosphatidylethanolamine (pe) recovered from a per 13c-labeled bacteria can be detected in environmental samples and used as measures of bacterial transport in the subsurface. detection of palmitic acid (16:0) and oleic acid (18:1) at m/z 271 (255+16) and 299 (281+18) as negative ions in pg and pe separated by high performance liquid chromatography (hplc) and detected after up-front collisionally induced dissociation (cid) utilizing electro ... | 2001 | 11240050 |
| map of the incp1beta plasmid ptsa encoding the widespread genes (tsa) for p-toluenesulfonate degradation in comamonas testosteroni t-2. | the catabolic incp1beta plasmid ptsa from comamonas testosteroni t-2 was mapped by subtractive analysis of restriction digests, by sequencing outwards from the tsa operon (toluenesulfonate degradation), and by generating overlapping, long-distance-pcr amplification products. the plasmid was estimated to comprise 72 +/- 4 kb. the tsa region was found to be a composite transposon flanked by two is1071 elements. a cryptic tsa operon was also present in the tsa transposon. those backbone genes and r ... | 2001 | 11282598 |
| 15n nmr relaxation studies of backbone dynamics in free and steroid-bound delta 5-3-ketosteroid isomerase from pseudomonas testosteroni. | the backbone dynamics of delta(5)-3-ketosteroid isomerase (ksi) from pseudomonas testosteroni has been studied in free enzyme and its complex with a steroid ligand, 19-nortestosterone hemisuccinate (19-nths), by (15)n relaxation measurements. the relaxation data were analyzed using the model-free formalism to extract the model-free parameters (s(2), tau(e), and r(ex)) and the overall rotational correlation time (tau(m)). the rotational correlation times were 19.23 +/- 0.08 and 17.08 +/- 0.07 ns ... | 2001 | 11300777 |
| folding mechanism of ketosteroid isomerase from comamonas testosteroni. | ketosteroid isomerase (ksi) from comamonas testosteroni is a homodimeric enzyme with 125 amino acids in each monomer catalyzing the allylic isomerization reaction at rates comparable to the diffusion limit. kinetic analysis of ksi refolding has been carried out to understand its folding mechanism. the refolding process as monitored by fluorescence change revealed that the process consists of three steps with a unimolecular fast, a bimolecular intermediate, and most likely unimolecular slow phase ... | 2001 | 11305917 |
| 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase from comamonas testosteroni: biological significance, three-dimensional structure and gene regulation. | 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase (3alpha-hsd/cr) catalyses the oxidoreduction at carbon 3 of steroid hormones and is postulated to initiate the complete mineralisation of the steroid nucleus to co(2) and h(2)o in comamonas testosteroni. the enzyme was found to be functional towards a variety of steroid substrates, including the steroid antibiotic fusidic acid. the enzyme also catalyses the carbonyl reduction of non-steroidal aldehydes and ketones such as a novel insecticide ... | 2001 | 11306088 |
| a model on the regulation of 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase expression in comamonas testosteroni. | 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase (3alpha-hsd/cr) from comamonas testosteroni is a key enzyme involved in the degradation of steroids and xenobiotic carbonyl compounds. the enzyme has recently been cloned and characterized by our group. a strong induction of enzyme activity is observed in the presence of steroids like testosterone. in the present investigation, two repressor proteins (rep1 and rep2) containing 78 and 420 amino acids, respectively, were found to regulate 3alp ... | 2001 | 11306089 |
| different mechanisms of the binding of soluble electron donors to the photosynthetic reaction center of rubrivivax gelatinosus and blastochloris viridis. | the tetraheme cytochrome subunits of the photosynthetic reaction centers (rcs) in two species of purple bacteria, rubrivivax gelatinosus and blastochloris (rhodopseudomonas) viridis, were compared in terms of their capabilities to bind different electron-donor proteins. the wild-type rcs from both species and mutated forms of r. gelatinosus rcs (with amino acid substitutions introduced to the binding domain for electron-donor proteins) were tested for their reactivity with soluble cytochromes an ... | 2001 | 11313347 |
| endotoxic properties of lipid a from comamonas testosteroni. | the lipid a from comamonas testosteroni has been isolated and its complete chemical structure determined [iida, t., haishima, y., tanaka, a., nishijima, k., saito, s. & tanamoto, k. (1996). eur j biochem 237, 468-475]. in this work, the relationship between its chemical structure and biological activity was studied. the lipid a was highly homogeneous chemically and was characterized by the relatively short chain length (c(10)) of the 3-hydroxy fatty acid components directly bound to the glucosam ... | 2001 | 11320112 |
| diversity in kinetics of trichloroethylene-degrading activities exhibited by phenol-degrading bacteria. | whole-cell kinetics of phenol- and trichloroethylene (tce)-degrading activities expressed by 13 phenol-degrading bacteria were analyzed. the ks (apparent affinity constant in haldane's equation) values for tce were unexpectedly diverse, ranging from 11 microm to over 800 microm. the vmax/ks values for phenol were three orders of magnitude higher than the values for tce in all bacteria analyzed, suggesting that these bacteria preferentially degrade phenol rather than tce. a positive correlation b ... | 2001 | 11330722 |
| isolation and characterization of two aerobic bacterial strains that completely degrade ethyl tert-butyl ether (etbe). | two bacterial strains, e1 and e2, isolated from gasoline-polluted soil completely degraded ethyl tert-butyl ether (etbe), as the sole source of carbon and energy, at specific rates of about 80 mg g(-1) and 58 mg g(-1) of cell protein day(-1), respectively. on the basis of morphological and phenotypic characteristics, strain e1 was tentatively identified as comamonas testosteroni and strain e2 as belonging to centre for disease control group a-5. the inhibitory effect of metyrapone on the degrada ... | 2001 | 11341318 |
| ferrographic tracking of bacterial transport in the field at the narrow channel focus area, oyster, va. | the first results from an innovative bacterial tracking technique, ferrographic capture, applied to bacterial transport in groundwater are reported in this paper. ferrographic capture was used to analyze samples during an october 1999 bacterial injection experiment at the narrow channel focus area of the south oyster site, va. data obtained using this method showed that the timing of bacterial breakthrough was controlled by physical (hydraulic conductivity) heterogeneity in the vertical dimensio ... | 2001 | 11352009 |
| isolation and characterization of polycyclic aromatic hydrocarbon-degrading bacteria associated with the rhizosphere of salt marsh plants. | polycyclic aromatic hydrocarbon (pah)-degrading bacteria were isolated from contaminated estuarine sediment and salt marsh rhizosphere by enrichment using either naphthalene, phenanthrene, or biphenyl as the sole source of carbon and energy. pasteurization of samples prior to enrichment resulted in isolation of gram-positive, spore-forming bacteria. the isolates were characterized using a variety of phenotypic, morphologic, and molecular properties. identification of the isolates based on their ... | 2001 | 11375181 |
| comamonas nitrativorans sp. nov., a novel denitrifier isolated from a denitrifying reactor treating landfill leachate. | a group of gram-negative denitrifying bacteria has been isolated from a denitrifying reactor treating landfill leachate. the new isolates produced both oxidase and catalase and showed growth on acetate, butyrate, n-caproate, i-butyrate, i-valerate, propionate, n-valerate, lactate, alanine, benzoate, phenylalanine and ethanol. no growth was observed on sugars. the bacteria could perform anoxic reduction of nitrate, nitrite and nitrous oxide to nitrogen, coupled to the oxidation of the same substr ... | 2001 | 11411724 |
| comamonas denitrificans sp. nov., an efficient denitrifying bacterium isolated from activated sludge. | to find a biomarker for denitrification in activated sludge, five denitrifying strains isolated from three wastewater treatment plants were studied. these strains were selected from among 1,500 isolates for their excellent denitrifying properties. they denitrify quickly and have no lag phase when switching from aerobic to anoxic conditions. all strains have the cd1-type of nitrite reductase. the strains are gram-negative rods and they all grow as filamentous chains when cultivated in liquid solu ... | 2001 | 11411726 |
| the interaction of protozoa with their potential prey bacteria in the rhizosphere. | extensive colonization of the rhizosphere by beneficial bacteria is desirable but it is not yet clear whether the feeding patterns of protozoa exert any ecological impact on the competence of bacteria in the rhizosphere. to determine whether the successful colonization of the rhizosphere by bacteria can be explained by inherent abilities of the bacteria to resist predation, six bacteria categorized as poor, mediocre or good rhizosphere colonists were tested. the populations of protozoa in the rh ... | 2001 | 11411840 |
| insights into the genetic diversity of initial dioxygenases from pah-degrading bacteria. | alpha subunit genes of initial polyaromatic hydrocarbon (pah) dioxygenases were used as targets for the pcr detection of pah-degrading strains of the genera pseudomonas, comamonas and rhodococcus which were obtained from activated sludge or soil samples. sequence analysis of pcr products from several pseudomonas strains showed that alpha subunits (nahac allele) of this genus are highly conserved. pcr primers for the specific detection of alpha subunit genes of initial pah dioxygenases from pseud ... | 2001 | 11414329 |
| phcs represses gratuitous expression of phenol-metabolizing enzymes in comamonas testosteroni r5. | we identified an open reading frame, designated phcs, downstream of the transcriptional activator gene (phcr) for the expression of multicomponent phenol hydroxylase (mph) in comamonas testosteroni r5. the deduced product of phcs was homologous to aphs of c. testosteroni ta441, which belongs to the gntr family of transcriptional regulators. the transformation of pseudomonas aeruginosa pao1c (phenol negative, catechol positive) with pror502 containing phcr and the mph genes conferred the ability ... | 2001 | 11418563 |
| post-antibiotic and synergic effects of fluoroquinolones and ceftazidime in combination against pseudomonas strains. | infectious complications are still the leading cause of morbidity and mortality in seriously ill patients [1-3]. to combat the resistance of (mainly gram-negative, non-fermentative) bacteria, e.g. pseudomonas aeruginosa, to a wide spectrum of antibiotics, drug combination therapy has been widely adopted as standard clinical practice since the late 1990s. beta-lactam combinations are not optimal and the potential of nephrotoxicity and ototoxicity from aminoglycosides has caused clinicians to eval ... | 2001 | 11426858 |
| resistance to antibiotics and biocides among non-fermenting gram-negative bacteria. | to investigate the antibiotic and biocide susceptibilities of clinical isolates of rarely encountered gram-negative, non-fermenting bacteria. | 2001 | 11442564 |
| identification and functional characterization of cbar, a marr-like modulator of the cbaabc-encoded chlorobenzoate catabolism pathway. | in comamonas testosteroni br60 (formerly alcaligenes sp. strain br60), catabolism of the pollutant 3-chlorobenzoate (3cba) is initiated by enzymes encoded by cbaabc, an operon found on composite transposon tn5271 of plasmid pbrc60. the cbaabc gene product cbaabc converts 3cba to protocatechuate (pca) and 5-cl-pca, which are then metabolized by the chromosomal pca meta (extradiol) ring fission pathway. in this study, cbaa was found to possess a sigma(70) type promoter. o(2) uptake experiments wit ... | 2001 | 11472929 |
| new inhibitors of iron-containing nitrile hydratases. | there is growing evidence in the literature emphasizing the significance of the post-translational modification of cysteine thiols to sulfenic acids (soh), which have been found in a number of proteins. crystallographic and mass spectrometric evidence has shown the presence of this group in an inactive form of the industrially important enzyme nitrile hydratase (nhase). this oxidized cysteine is unique in that it forms part of the coordination sphere of the low-spin iron iii at the active site o ... | 2001 | 11481039 |
| comamonas testosteroni br6020 possesses a single genetic locus for extradiol cleavage of protocatechuate. | a key intermediate for biodegradation of various distinct aromatic growth substrates in comamonas testosteroni is protocatechuate (pca), which is metabolized by the 4,5-extradiol (meta) ring fission pathway. a locus harbouring genes from c. testosteroni br6020 was cloned, dubbed pmd, which encodes the enzymes that degrade pca. the identity of pmdab, encoding respectively the alpha- and beta-subunit of the pca ring-cleavage enzyme, was confirmed by n-terminal sequencing and molecular mass determi ... | 2001 | 11495993 |
| meta-cleavage enzyme gene tesb is necessary for testosterone degradation in comamonas testosteroni ta441. | comamonas testosteroni metabolizes testosterone as the sole carbon source via a meta-cleavage reaction. a meta-cleavage enzyme gene, tesb, was cloned from c. testosteroni ta441. the deduced n-terminal amino acid sequence of tesb matched that of the purified meta-cleavage enzyme which is induced in ta441 during growth on testosterone as the sole carbon source. the tesb-disrupted mutant did not show growth on testosterone, suggesting that tesb is necessary for ta441 to grow on testosterone. downst ... | 2001 | 11739769 |
| characterization of hybrid biphenyl dioxygenases obtained by recombining burkholderia sp. strain lb400 bpha with the homologous gene of comamonas testosteroni b-356. | the bacterial degradation of polychlorinated biphenyls depends on the ability of the enzyme biphenyl 2,3-dioxygenase (bpdo) to catalyze their oxygenation. analysis of hybrid bpdos obtained using common restriction sites to exchange large dna fragments between lb400 bpha and b-356 bpha showed that the c-terminal portion of lb400 alpha subunit can withstand extensive structural modifications, and that these modifications can change the catalytic properties of the enzyme. on the other hand, exchang ... | 2001 | 11766051 |
| method for qualifying microbial removal performance of 0.1 micron rated filters. part i: characterization of water isolates for potential use as standard challenge organisms to qualify 0.1 micron rated filters. | although 0.1 microm rated filters intended for pharmaceutical sterilization applications have been commercially available for at least 15 years, there is no industry-wide standard for qualifying the microbial removal performance of these filters. in this article, we report on the bacterial challenge methodology used to screen four bacterial species for potential utility as a standard challenge organism to qualify 0.1 microm rated filters. these isolates were, in their natural state, demonstrated ... | 2001 | 11766822 |
| [auxotrophy and utilization of oxidized and reduced mineral sulfur forms by brevundimonas diminuta strains]. | connection between auxotrophy of brevundimonas diminuta strains for sulphur-containing amino acids and presence of oxidized or reduced sulphur forms in the medium has been shown. when grown in synthetic medium supplied with sulphate or sulphite b. diminuta strains required cystine, biotin, pantothenate and vitamin b12 for growth and utilized very limited spectrum--from 8 to 12--carbon sources. in the presence of 5 g/l of thiosulphate in the medium instead of mentioned sulphur-containing salts st ... | 2001 | 11785417 |
| soil microbial population dynamics following bioaugmentation with a 3-chlorobenzoate-degrading bacterial culture. bioaugmentation effects on soil microorganisms. | changes in microbial populations were evaluated following inoculation of contaminated soil with a 3-chlorobenzoate degrader. madera sandy loam was amended with 0, 500, or 1,000 microg 3-chlorobenzoate g(-1) dry soil. selected microcosms were inoculated with the degrader comamonas testosteroni br60. culturable bacterial degraders were enumerated on minimal salts media containing 3-chlorobenzoate. culturable heterotrophic bacteria were enumerated on r2a. isolated degraders were grouped by enteroba ... | 2001 | 11998824 |
| aniline and 3-chloroaniline degrading bacteria: genetics and possible applications. | 2001 | 15954269 | |
| rhizoremediation of a 3,4-dichloroaniline contaminated soil. | 2001 | 15954271 | |
| relationships within the proteobacteria of plant pathogenic acidovorax species and subspecies, burkholderia species, and herbaspirillum rubrisubalbicans by sequence analysis of 16s rdna, numerical analysis and determinative tests. | sequence data for 16s rdna of the type strains of acidovorax avenae subsp. avenae, a. avenae subsp. cattleyae, a. avenae subsp. citrulli, a. konjaci and herbaspirillum rubrisubalbicans were compared with genbank library accessions of burkholderia spp., comamonas sp., ralstonia solanacearum and variovorax sp. maximum parsimony analysis produced two clusters: 1. acidovorax spp., comamonas sp., and variovorax sp. (all in the comamonadaceae), and 2. burkholderia spp., ralstonia solanacearum, and her ... | 2001 | 11827206 |
| bioreactor design studies for a hydrogen-producing bacterium. | carbon monoxide (co) can be metabolized by a number of microorganisms along with water to produce hydrogen (h2) and carbon dioxide. national renewable energy laboratory researchers have isolated a number of bacteria that perform this so-called water-gas shift reaction at ambient temperatures. we performed experiments to measure the rate of co conversion and h2 production in a trickle-bed reactor (tbr). the liquid recirculation rate and the reactor support material both affected the mass transfer ... | 2002 | 12018287 |
| electrostatic properties of the anion selective porin omp32 from delftia acidovorans and of the arginine cluster of bacterial porins. | the functional properties of the anion-selective porin omp32 from the bacterium delftia acidovorans, formerly comamonas acidovorans, are determined by the particularly narrow channel constriction and the electrostatic field inside and outside the pore. a cluster of arginines (arg 38, arg 75, and arg 133) determines the electrostatic field close to the constriction zone. stacked amino acids carrying charges are prone to drastic pk(a) shifts. however, optimized calculations of the titration behavi ... | 2002 | 12021430 |
| characterization of unusual bacteria isolated from respiratory secretions of cystic fibrosis patients and description of inquilinus limosus gen. nov., sp. nov. | using a polyphasic approach (including cellular protein and fatty acid analysis, biochemical characterization, 16s ribosomal dna sequencing, and dna-dna hybridizations), we characterized 51 bacterial isolates recovered from respiratory secretions of cystic fibrosis (cf) patients. our analyses showed that 24 isolates belong to taxa that have so far not (or only rarely) been reported from cf patients. these taxa include acinetobacter sp., bordetella hinzii, burkholderia fungorum, comamonas testost ... | 2002 | 12037065 |
| identification of a novel comamonas testosteroni gene encoding a steroid-inducible extradiol dioxygenase. | comamonas testosteroni is a gram-negative bacterium that can grow on steroids and polycyclic aromatic hydrocarbons (pah) as sole carbon and energy source. complete mineralisation of these compounds is achieved through complex metabolic pathways comprising a set of inducible enzymes. whereas the degradation pathways for pahs have been intensively studied, patterns of enzymes leading to ring fissions of the steroid nucleus are unclear. several intermediates of the steroid and pah degradation pathw ... | 2002 | 12056803 |
| significance of electrophoretic mobility distribution to bacterial transport in granular porous media. | a method is developed to obtain the electrophoretic mobility distribution of colloidal particles by microelectrophoresis. the results demonstrate that for small particles (< 1 microm), the experimental mobility distribution must be deconvoluted to remove the effect of the random brownian motion so that the electrophoretic mobility distribution can be obtained. for bacteria-sized particles (on the order of 1 microm or larger), the random brownian motion is not significant, and the experimental mo ... | 2002 | 12069893 |
| family shuffling of a targeted bpha region to engineer biphenyl dioxygenase. | in this work we used a new strategy designed to reduce the size of the library that needs to be explored in family shuffling to evolve new biphenyl dioxygenases (bpdos). instead of shuffling the whole gene, we have targeted a fragment of bpha that is critical for enzyme specificity. we also describe a new protocol to screen for more potent bpdos that is based on the detection of catechol metabolites from chlorobiphenyls. several bpha variants with extended potency to degrade polychlorinated biph ... | 2002 | 12081948 |
| an arac/xyls family member at a high level in a hierarchy of regulators for phenol-metabolizing enzymes in comamonas testosteroni r5. | comamonas testosteroni strain r5 expresses a higher level of phenol-oxygenating activity than any other bacterial strain so far characterized. the expression of the operon encoding multicomponent phenol hydroxylase (mph), which is responsible for the phenol-oxygenating activity, is controlled by two transcriptional regulators, phcs and phcr, in strain r5. in this study, we identified a third transcriptional regulator for the mph operon (phct) that belongs to the arac/xyls family. while the disru ... | 2002 | 12081966 |
| changes in bacterioplankton community structure and activity with depth in a eutrophic lake as revealed by 5s rrna analysis. | the community structure of bacterioplankton was studied at different depths (0 to 25 m) of a temperate eutrophic lake (lake plusssee in northern germany) by using comparative 5s rrna analysis. the relative amounts of taxonomic groups were estimated from 5s rrna bands separated by high-resolution electrophoresis. comparison of partial 5s rrna sequences enabled detection of changes in single taxa over space and during seasons. overall, the bacterioplankton community was dominated by 3 to 14 abunda ... | 2002 | 12089049 |
| oxidative stress-induced expression of catalases in comamonas terrigena. | when grown under oxidative stress, catalatic as well as peroxidatic activity is increased in the gram-negative bacterium comamonas terrigena n3h. two distinct hydroperoxidases were demonstrated by a specific staining. based on their molar masses and their sensitivity toward 3-amino-1,2,4-triazole and high temperatures, they were identified as dimeric catalase-1 (cat-1; 150 kda), and as a tetrameric catalase-2 (cat-2; 240 kda) with enhanced peroxidatic activity, respectively. these two catalases ... | 2002 | 12094731 |
| bioconversion of 3 beta-acetoxypregna-5,16-diene-20-one to androsta-1,4-diene-3,17-dione by mixed bacterial culture. | to isolate a bacterium capable of degrading 3 beta-acetoxypregna-5,16-diene-20-one (16-dpa) to androsta-1,4-diene-3,17-dione (add) and to decipher the biodegradation pathway. | 2002 | 12100580 |
| novel alpha-glucosidase inhibitors, ckd-711 and ckd-711a produced by streptomyces sp. ck-4416. ii. biological properties. | ckd-711 and ckd-711a are aminooligosaccharide alpha-glucosidase inhibitors discovered during the bioactive material screening for antibacterial agent. their inhibitory activities were studied and compared with those of acarbose in vitro and in vivo with animals. in in vitro study, ckd-711 showed similar effects to acarbose on porcine intestinal maltase and sucrase, ic50s of 2.5 and 0.5 microg/ml, respectively, whereas it had about 2 fold lower alpha-amylase inhibitory activity (ic50, 78.0 microg ... | 2002 | 12139014 |
| transfer of microorganisms, including listeria monocytogenes, from various materials to beef. | the quantity of microorganisms that may be transferred to a food that comes into contact with a contaminated surface depends on the density of microorganisms on the surface and on the attachment strengths of the microorganisms on the materials. we made repeated contacts between pieces of meat and various surfaces (stainless steel and conveyor belt materials [polyvinyl chloride and polyurethane]), which were conditioned with meat exudate and then were contaminated with listeria monocytogenes, sta ... | 2002 | 12147503 |
| characterization of an acetate-degrading sludge without intracellular accumulation of polyphosphate and glycogen. | a sequencing batch reactor (sbr) was operated in the conventional anaerobic-aerobic mode for enhanced biological phosphate removal (ebpr) using acetate as the sole substrate. results showed that, however, the reactor was unable to remove phosphate from wastewater. the sludge containing 1.65% of phosphate did not exhibit the typical characteristics of polyphosphate-accumulating organisms (pao) or glycogen-accumulating organisms (gao). phylogenetic analysis, based on 16s rdna sequences of individu ... | 2002 | 12188117 |
| characterization of four olive-mill-wastewater indigenous bacterial strains capable of aerobically degrading hydroxylated and methoxylated monocyclic aromatic compounds. | seven aerobic bacterial strains capable of degrading several of the monocyclic aromatic compounds occurring in the phenolic fraction of olive-mill wastewaters (omws) were isolated from an italian omw. the results of the 16s rdna restriction analysis evidenced that these strains are distributed among four different groups. one strain of each group was taxonomically characterized by sequencing the amplified 16s rdna, and the four strains were assigned to the genera comamonas (strain av1a), ralston ... | 2002 | 12189422 |
| mathematical analysis of solid-liquid mass transfer in a batch reactor for the enzymatic transformation of testosterone to 4ad. | a previous mathematical analysis of mass transfer in a two-phase (solid-liquid) batch reactor for enzymatic transformation of testosterone to 4ad (pereira et al., 1987) is extended to incorporate the effect of convective mixing. the results of the analysis showed that for a given enzyme loading, the mass transfer resistance in the solid (a function of the bead size) and the intensity of convective mixing (as embodied in the mass transfer coefficient) are two parameters that can be varied such th ... | 2002 | 12209812 |
| flow cytometry analysis of changes in the dna content of the polychlorinated biphenyl degrader comamonas testosteroni tk102: effect of metabolites on cell-cell separation. | flow cytometry was used to monitor changes in the dna content of the polychlorinated biphenyl (pcb)-degrading bacterium comamonas testosteroni tk102 during growth in the presence or absence of pcbs. in culture medium without pcbs, the majority of stationary-phase cells contained a single chromosome. in the presence of pcbs, the percentage of cells containing two chromosomes increased from 12% to approximately 50%. in contrast, addition of pcbs did not change the dna contents of three species tha ... | 2002 | 12324361 |
| molecular characterization and substrate specificity of nitrobenzene dioxygenase from comamonas sp. strain js765. | comamonas sp. strain js765 can grow with nitrobenzene as the sole source of carbon, nitrogen, and energy. we report here the sequence of the genes encoding nitrobenzene dioxygenase (nbdo), which catalyzes the first step in the degradation of nitrobenzene by strain js765. the components of nbdo were designated reductase(nbz), ferredoxin(nbz), oxygenase(nbzalpha), and oxygenase(nbzbeta), with the gene designations nbzaa, nbzab, nbzac, and nbzad, respectively. sequence analysis showed that the comp ... | 2002 | 11823201 |
| molecular detection and diversity of polycyclic aromatic hydrocarbon-degrading bacteria isolated from geographically diverse sites. | nineteen polycyclic aromatic hydrocarbon (pah)-degrading bacteria were isolated from environmental samples in kuwait, indonesia, thailand, and japan by enrichment with either naphthalene or phenanthrene as a sole carbon source. sequence analyses of the 16-s rrna gene indicated that at least seven genera (ralstonia, sphingomonas, burkholderia, pseudomonas, comamonas, flavobacterium, and bacillus) were present in this collection. determination of the ability of the isolates to use pah and its pres ... | 2002 | 11876413 |
| characterization of tdt genes for the degradation of tricyclic diterpenes by pseudomonas diterpeniphila a19-6a. | resin acids are tricyclic diterpenes that are toxic to aquatic life when released in high concentrations in pulp mill effluents. these naturally formed organic acids are readily degraded by bacteria and fungi; nevertheless, many of the mechanisms involved are still unknown. we report the localization, cloning, and sequencing of genes for abietane degradation (9.18 kb; designated tdt (tricyclic diterpene) lrsabcd) from the gamma-proteobacterium pseudomonas diterpeniphila a19-6a. using gene knocko ... | 2002 | 11888163 |
| rapid assessment of the physiological status of the polychlorinated biphenyl degrader comamonas testosteroni tk102 by flow cytometry. | the viability of the polychlorinated biphenyl-degrading bacterium comamonas testosteroni tk102 was assessed by flow cytometry (fcm) with the fluorogenic ester calcein-am (cam) and the nucleic acid dye propidium iodide (pi). cam stained live cells, whereas pi stained dead cells. when double staining with cam and pi was performed, three physiological states, i.e., live (calcein positive, pi negative), dead (calcein negative, pi positive), and permeabilized (calcein positive, pi positive), were det ... | 2002 | 11916727 |
| relative dominance of physical versus chemical effects on the transport of adhesion-deficient bacteria in intact cores from south oyster, virginia. | bacterial transport experiments were conducted using intact sediment cores collected from sites on the delmarva peninsula near south oyster, va, to delineate the relative importance of physical and chemical heterogeneity in controlling transport of an adhesion-deficient bacterial strain. electron microscopy revealed that the sediments consisted of quartz and feldspar with a variable amount of clay and iron and aluminum hydroxide coatings on the grains. a nonmotile, gram-negative indigenous groun ... | 2002 | 11918012 |
| comamonas koreensis sp. nov., a non-motile species from wetland in woopo, korea. | a bacterial strain, designated yh12t, was isolated from a wetland sample collected from woopo, republic of korea, and characterized using a polyphasic approach. analysis of 16s rdna indicated that the isolate formed a monophyletic clade with the members of the genus comamonas. the closest phylogenetic relative among the valid species was comamonas testosteroni, with 96.6% 16s rdna similarity. the chemotaxonomic properties of the wetland isolate supported its membership of the genus comamonas, as ... | 2002 | 11931145 |
| simultaneous transport of two bacterial strains in intact cores from oyster, virginia: biological effects and numerical modeling. | the transport characteristics of two adhesion-deficient, indigenous groundwater strains, comamonas sp. strain da001 and erwinia herbicola oys2-a, were studied by using intact sediment cores (7 by 50 cm) from oyster, va. both strains are gram-negative rods (1.10 by 0.56 and 1.56 by 0.46 microm, respectively) with strongly hydrophilic membranes and a slightly negative surface charge. the two strains exhibited markedly different behaviors when they were transported through granular porous sediment. ... | 2002 | 11976080 |
| stable augmentation of activated sludge with foreign catabolic genes harboured by an indigenous dominant bacterium. | comamonas sp. rn7 is a phenol-degrading bacterium that represents the dominant catabolic population in activated sludge. the present study examined the utility of this bacterium for establishing foreign catabolic genes in phenol-digesting activated sludge. the phc genes coding for phenol hydroxylase and its transcriptional regulators of c. testosteroni r5 were integrated into the chromosome of strain rn7. the specific phenol-oxygenating activity of a resultant transformant designated rn7(r503) w ... | 2002 | 12366752 |
| cloning and characterization of a gene cluster involved in cyclopentanol metabolism in comamonas sp. strain ncimb 9872 and biotransformations effected by escherichia coli-expressed cyclopentanone 1,2-monooxygenase. | cyclopentanone 1,2-monooxygenase, a flavoprotein produced by pseudomonas sp. strain ncimb 9872 upon induction by cyclopentanol or cyclopentanone (m. griffin and p. w. trudgill, biochem. j. 129:595-603, 1972), has been utilized as a biocatalyst in baeyer-villiger oxidations. to further explore this biocatalytic potential and to discover new genes, we have cloned and sequenced a 16-kb chromosomal locus of strain 9872 that is herein reclassified as belonging to the genus comamonas: sequence analysi ... | 2002 | 12406764 |