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1.
Clin Oncol (R Coll Radiol) ; 33(12): 751-760, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33966948

RESUMO

AIMS: Electronic patient-reported outcome (ePRO) measures have the potential to improve patient care, both at an individual level by detecting symptoms and at an organisational level to rationalise follow-up. The introduction of ePROs has many challenges, including funding, institutional rigidity and acceptability for both patients and clinicians. There are multiple examples of successful ePRO programmes but no specific feasibility studies in those who are less digitally engaged. Prostate cancer is predominantly a disease of older men and digital exclusion is associated with increased age. We assessed the feasibility of ePRO completion in older men receiving treatment for advanced prostate cancer both within the clinic and from home. MATERIALS AND METHODS: Men receiving palliative systemic treatment were asked to complete ePROs on a tablet computer in the outpatient department at 0 and 3 months. Participants were also offered optional completion from home. Feasibility was assessed via a mixed methods approach. RESULTS: On-site ePRO completion was acceptable to most patients, with 90% finding it easy or straightforward and 80% preferring electronic over paper. Remote completion was more challenging, even for those who accessed e-mail daily and owned a tablet, with only 20% of participants successfully completing ePROs. Barriers to electronic completion can be categorised as technical, attitudinal and medical. Quality of life and symptom ePRO results were comparable with published data. CONCLUSIONS: On-site completion is achievable in this population with limited staff support. However, remote completion requires further work to improve systems and acceptability for patients. Remote completion is critical to add significantly to current clinical care by detecting symptoms or stratifying follow-up.


Assuntos
Neoplasias da Próstata , Qualidade de Vida , Idoso , Eletrônica , Estudos de Viabilidade , Humanos , Masculino , Medidas de Resultados Relatados pelo Paciente , Neoplasias da Próstata/tratamento farmacológico
2.
J Appl Microbiol ; 102(5): 1227-38, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17448158

RESUMO

AIMS: To investigate the distribution of a polymicrobial community of biodegradative bacteria in (i) soil and groundwater at a former manufactured gas plant (FMGP) site and (ii) in a novel SEquential REactive BARrier (SEREBAR) bioremediation process designed to bioremediate the contaminated groundwater. METHODS AND RESULTS: Culture-dependent and culture-independent analyses using denaturing gradient gel electrophoresis (DGGE) and polymerase chain reaction (PCR) for the detection of 16S ribosomal RNA gene and naphthalene dioxygenase (NDO) genes of free-living (planktonic groundwater) and attached (soil biofilm) samples from across the site and from the SEREBAR process was applied. Naphthalene arising from groundwater was effectively degraded early in the process and the microbiological analysis indicated a dominant role for Pseudomonas and Comamonas in its degradation. The microbial communities appeared highly complex and diverse across both the sites and in the SEREBAR process. An increased population of naphthalene degraders was associated with naphthalene removal. CONCLUSION: The distribution of micro-organisms in general and naphthalene degraders across the site was highly heterogeneous. Comparisons made between areas contaminated with polycyclic aromatic hydrocarbons (PAH) and those not contaminated, revealed differences in the microbial community profile. The likelihood of noncultured bacteria being dominant in mediating naphthalene removal was evident. SIGNIFICANCE AND IMPACT OF THE STUDY: This work further emphasizes the importance of both traditional and molecular-based tools in determining the microbial ecology of contaminated sites and highlights the role of noncultured bacteria in the process.


Assuntos
Bactérias/classificação , Ecossistema , Microbiologia do Solo , Poluentes do Solo/metabolismo , Microbiologia da Água , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Biodegradação Ambiental , Hidrocarbonetos Policíclicos Aromáticos , Reação em Cadeia da Polimerase
3.
Appl Microbiol Biotechnol ; 73(3): 691-5, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16802151

RESUMO

Gentisate-1,2-dioxygenase genes (gdoA), with homology to a number of bacterial dioxygenases, and genes encoding a putative coenzyme A (CoA)-synthetase subunit (acdB) and a CoA-thioesterase (tieA) were identified in two haloarchaeal isolates. In Haloarcula sp. D1, gdoA was expressed during growth on 4-hydroxybenzoate but not benzoate, and acdB and tieA were not expressed during growth on any of the aromatic substrates tested. In contrast, gdoA was expressed in Haloferax sp. D1227 during growth on benzoate, 3-hydroxybenzoate, cinnamate and phenylpropionate, and both acdB and tieA were expressed during growth on benzoate, cinnamate and phenylpropionate, but not on 3-hydroxybenzoate. This pattern of induction is consistent with these genes encoding steps in a CoA-mediated benzoate pathway in this strain.


Assuntos
Dioxigenases/genética , Genes Arqueais , Haloarcula/genética , Haloferax/genética , Benzoatos/metabolismo , Clonagem Molecular , DNA Arqueal/genética , Perfilação da Expressão Gênica , Haloarcula/enzimologia , Haloferax/enzimologia , Dados de Sequência Molecular , Alinhamento de Sequência
5.
Appl Environ Microbiol ; 68(12): 6246-55, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12450849

RESUMO

A novel haloarchaeal strain, Haloarcula sp. strain D1, grew aerobically on 4-hydroxybenzoic acid (4HBA) as a sole carbon and energy source and is the first member of the domain Archaea reported to do so. Unusually, D1 metabolized 4HBA via gentisic acid rather than via protocatechuic acid, hydroquinone, or catechol. Gentisate was detected in 4HBA-grown cultures, and gentisate 1,2-dioxygenase activity was induced in 4HBA-grown cells. Stoichiometric accumulation of gentisate from 4HBA was demonstrated in 4HBA-grown cell suspensions containing 2,2'-dipyridyl (which strongly inhibits gentisate 1,2-dioxygenase). To establish whether initial 1-hydroxylation of 4HBA with concomitant 1,2-carboxyl group migration to yield gentisate occurred, 2,6-dideutero-4HBA was synthesized and used as a substrate. Deuterated gentisate was recovered from cell suspensions and identified as 3-deutero-gentisate, using gas chromatography-mass spectrometry and proton nuclear magnetic resonance spectroscopy. This structural isomer would be expected only if a 1,2-carboxyl group migration had taken place, and it provides compelling evidence that the 4HBA pathway in Haloarcula sp. strain D1 involves a hydroxylation-induced intramolecular migration. To our knowledge, this is the first report of a pathway which involves such a transformation (called an NIH shift) in the domain Archaea.


Assuntos
Gentisatos , Haloarcula/metabolismo , Parabenos/metabolismo , 2,2'-Dipiridil/metabolismo , Aerobiose , Biotransformação , Haloarcula/crescimento & desenvolvimento , Hidroxibenzoatos/metabolismo , Espectroscopia de Ressonância Magnética
6.
Water Sci Technol ; 46(1-2): 115-8, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12216611

RESUMO

Physiological studies on M. parvicella have been conducted to determine the rate of growth of this organism in pure culture. The organism displayed a doubling time of 128 days despite its profuse abundance in a local Wastewater Treatment Plant (WWTW). An extensive survey has been ongoing since February 2000 into the extent of M. parvicella in the WWTW. A suite of monoclonal and polyclonal antibodies has been developed to detect and quantify M. parvicella.


Assuntos
Actinobacteria/isolamento & purificação , Anticorpos Antibacterianos/análise , Esgotos/microbiologia , Eliminação de Resíduos Líquidos , Actinobacteria/imunologia , Anticorpos Monoclonais , Dinâmica Populacional
7.
J Ind Microbiol Biotechnol ; 29(2): 75-82, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12161774

RESUMO

Bacteria isolated previously from ultrapure water (UPW) systems were examined for their ability to survive in UPW, with the ultimate goal of elucidating potential carbon and energy sources for the bacteria. Two strains of Ralstonia pickettii isolated from different areas within the UPW system (pretreatment and polishing loop, and referred to as strains 3A1 and MF254A, respectively) and a strain of Bradyrhizobium sp. were compared to increase our understanding of the fundamental behavior of bacteria contaminating UPW. R. pickettii (3A1) grew significantly slower in R2A medium, with a final cell yield much lower than the isolate from the polishing loop. In addition, R. pickettii MF254A showed a broader substrate range than either strain 3A1 or Bradyrhizobium sp. In UPW, there appears to be a threshold cell concentration (approximately 10(6) colony-forming units/ml), whereby the cell numbers remain constant for a prolonged period of 6 months or more. Below this concentration, rapid proliferation is observed until the threshold concentration is attained. Preliminary experiments suggested that nitrogen gas (frequently added to UPW storage tanks) may contribute to growth of Bradyrhizobium sp. Above the threshold concentration, the strain of Ralstonia sp. isolated from the polishing loop was capable of cryptic growth with heat-killed cells in UPW. However, cryptic growth was not observed when the cells supplied as nutrients were killed using UV254 light. Furthermore, cryptic growth did not appear to contribute significantly to proliferation of Bradyrhizobium sp. or Ralstonia sp. 3A1 (isolated from the pretreatment loop). We believe that cryptic growth may aid survival of the bacteria in UPW, but further experiments are warranted to prove this phenomenon conclusively.


Assuntos
Bacilos e Cocos Aeróbios Gram-Negativos/isolamento & purificação , Bacilos e Cocos Aeróbios Gram-Negativos/metabolismo , Microbiologia da Água , Purificação da Água , Contagem de Colônia Microbiana , Meio Ambiente , Bacilos e Cocos Aeróbios Gram-Negativos/classificação , Bacilos e Cocos Aeróbios Gram-Negativos/efeitos da radiação , Temperatura Alta , Fatores de Tempo , Raios Ultravioleta
8.
Q J Exp Psychol B ; 54(1): 27-51, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11216299

RESUMO

We investigated blocking and retrospective revaluation of causal judgements using a scenario in which food cues acted as potential causes of an allergic reaction as the outcome. In the blocking contingency, the treatment cues were either paired or unpaired with the outcome prior to a second stage in which sequential compounds of treatment and target cues were paired with the outcome. The order of this compound and treatment training was reversed in retrospective revaluation contingencies. When the interstimulus interval between the treatment and target cues was unfilled on compound trials (Experiments 1 and 3), both blocking and retrospective revaluation were observed in that the target cue trained in compound with the paired treatment cue attracted lower causal ratings than the target cue trained in compound with the unpaired treatment cue. By contrast, performing a mental arithmetic task using numerals presented during the interstimulus interval had no effect on the magnitude of blocking but rendered retrospective revaluation unreliable (Experiments 2 and 3). These results provide further support for accounts of revaluation based upon within-compound associations.


Assuntos
Aprendizagem por Associação , Atenção , Resolução de Problemas , Adulto , Feminino , Hipersensibilidade Alimentar/psicologia , Preferências Alimentares/psicologia , Humanos , Masculino , Software
9.
Rapid Commun Mass Spectrom ; 14(15): 1316-20, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10920348

RESUMO

Degradation experiments of benzoate by Pseudomonas putida resulted in enzymatic carbon isotope fractionations. However, isotopic temperature effects between experiments at 20 and 30 degrees C were minor. Averages of the last three values of the CO(2) isotopic composition (delta(13)C(CO2(g))) were more negative than the initial benzoate delta(13)C value (-26.2 per thousand Vienna Pee Dee Belenite (VPDB)) by 3.8, 3.4 and 3.2 per thousand at 20, 25 and 30 degrees C, respectively. Although the maximum isotopic temperature difference found was only 0.6 per thousand, more extreme temperature variations may cause larger isotope effects. In order to understand the isotope effects on the total inorganic carbon (TIC), a better measure is to calculate the proportions of the inorganic carbon species (CO(2)(g), CO(2)(aq) and HCO(3)(-)) and to determine their cumulative delta(13)C(TIC). In all three experiments delta(13)C(TIC) was more positive than the initial isotopic composition of the benzoate at a pH of 7. This suggests an uptake of (12)C in the biomass in order to match the carbon balance of these closed system experiments.


Assuntos
Benzoatos/química , Carbono/análise , Pseudomonas putida/química , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Pseudomonas putida/crescimento & desenvolvimento , Solubilidade , Temperatura
10.
J Bacteriol ; 182(10): 2725-31, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10781539

RESUMO

The sequences of the 16S rRNA and haloalkane dehalogenase (dhaA) genes of five gram-positive haloalkane-utilizing bacteria isolated from contaminated sites in Europe, Japan, and the United States and of the archetypal haloalkane-degrading bacterium Rhodococcus sp. strain NCIMB13064 were compared. The 16S rRNA gene sequences showed less than 1% sequence divergence, and all haloalkane degraders clearly belonged to the genus Rhodococcus. All strains shared a completely conserved dhaA gene, suggesting that the dhaA genes were recently derived from a common ancestor. The genetic organization of the dhaA gene region in each of the haloalkane degraders was examined by hybridization analysis and DNA sequencing. Three different groups could be defined on the basis of the extent of the conserved dhaA segment. The minimal structure present in all strains consisted of a conserved region of 12.5 kb, which included the haloalkane-degradative gene cluster that was previously found in strain NCIMB13064. Plasmids of different sizes were found in all strains. Southern hybridization analysis with a dhaA gene probe suggested that all haloalkane degraders carry the dhaA gene region both on the chromosome and on a plasmid (70 to 100 kb). This suggests that an ancestral plasmid was transferred between these Rhodococcus strains and subsequently has undergone insertions or deletions. In addition, transposition events and/or plasmid integration may be responsible for positioning the dhaA gene region on the chromosome. The data suggest that the haloalkane dehalogenase gene regions of these gram-positive haloalkane-utilizing bacteria are composed of a single catabolic gene cluster that was recently distributed worldwide.


Assuntos
Alcanos/metabolismo , Sequência Conservada , Genes Bacterianos , Hidrocarbonetos Halogenados/metabolismo , Hidrolases/genética , Família Multigênica , Rhodococcus/enzimologia , Sequência de Bases , Mapeamento Cromossômico , DNA Bacteriano , Dados de Sequência Molecular , RNA Bacteriano/análise , RNA Ribossômico 16S/análise , Rhodococcus/genética , Rhodococcus/isolamento & purificação , Análise de Sequência de RNA
11.
J Bacteriol ; 182(8): 2191-9, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10735862

RESUMO

The haloalkane-degrading bacteria Rhodococcus rhodochrous NCIMB13064, Pseudomonas pavonaceae 170, and Mycobacterium sp. strain GP1 share a highly conserved haloalkane dehalogenase gene (dhaA). Here, we describe the extent of the conserved dhaA segments in these three phylogenetically distinct bacteria and an analysis of their flanking sequences. The dhaA gene of the 1-chlorobutane-degrading strain NCIMB13064 was found to reside within a 1-chlorobutane catabolic gene cluster, which also encodes a putative invertase (invA), a regulatory protein (dhaR), an alcohol dehydrogenase (adhA), and an aldehyde dehydrogenase (aldA). The latter two enzymes may catalyze the oxidative conversion of n-butanol, the hydrolytic product of 1-chlorobutane, to n-butyric acid, a growth substrate for many bacteria. The activity of the dhaR gene product was analyzed in Pseudomonas sp. strain GJ1, in which it appeared to function as a repressor of dhaA expression. The 1,2-dibromoethane-degrading strain GP1 contained a conserved DNA segment of 2.7 kb, which included dhaR, dhaA, and part of invA. A 12-nucleotide deletion in dhaR led to constitutive expression of dhaA in strain GP1, in contrast to the inducible expression of dhaA in strain NCIMB13064. The 1, 3-dichloropropene-degrading strain 170 possessed a conserved DNA segment of 1.3 kb harboring little more than the coding region of the dhaA gene. In strains 170 and GP1, a putative integrase gene was found next to the conserved dhaA segment, which suggests that integration events were responsible for the acquisition of these DNA segments. The data indicate that horizontal gene transfer and integrase-dependent gene acquisition were the key mechanisms for the evolution of catabolic pathways for the man-made chemicals 1, 3-dichloropropene and 1,2-dibromoethane.


Assuntos
Proteínas de Escherichia coli , Evolução Molecular , Transferência Genética Horizontal , Genes Bacterianos , Hidrocarbonetos Halogenados/metabolismo , Hidrolases/genética , Recombinação Genética , Compostos Alílicos/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Biodegradação Ambiental , Sequência Conservada , Elementos de DNA Transponíveis , Proteínas de Ligação a DNA/metabolismo , Poluentes Ambientais/metabolismo , Dibrometo de Etileno/metabolismo , Regulação Bacteriana da Expressão Gênica , Hidrocarbonetos Bromados , Hidrocarbonetos Clorados , Integrases/genética , Dados de Sequência Molecular , Mycobacterium/enzimologia , Mycobacterium/genética , Pseudomonas/enzimologia , Pseudomonas/genética , Rhodococcus/enzimologia , Rhodococcus/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Transativadores/metabolismo
12.
Q J Exp Psychol B ; 53(1): 59-81, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10718060

RESUMO

In three experiments, participants learned which of a variety of foods were capable of causing an allergic reaction in a hypothetical patient during training in which a compound of a treatment and a target food cue was paired with the reaction. In Experiment 1 the causal ratings of the target cue were increased if the treatment cue was pretrained as a preventative cause of the reaction. Experiments 2 and 3 demonstrated that the magnitude of this super-learning is unaffected by the order of compound and treatment cue training. The final study also showed that forward super-learning is not induced solely by simple exposure to the treatment cue prior to compound training but, rather, depends upon training the treatment cue as a preventative cause, whereas retrospective super-learning may be due merely to exposure of the treatment cue. These results are problematic for contingency-based accounts of causal induction but accord with modified and extended associative theories.


Assuntos
Aprendizagem por Associação , Condicionamento Clássico , Julgamento , Sobreaprendizagem , Adulto , Causalidade , Sinais (Psicologia) , Feminino , Hipersensibilidade Alimentar/prevenção & controle , Hipersensibilidade Alimentar/psicologia , Humanos , Masculino , Aprendizagem por Probabilidade
13.
FEMS Microbiol Lett ; 182(2): 327-31, 2000 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-10620687

RESUMO

Rhodococcus sp. NCIMB112038 can utilize naphthalene as its sole carbon and energy source. The gene encoding cis-naphthalene dihydrodiol dehydrogenase (narB) of this strain has been cloned and sequenced. Expression of NCIMB12038 cis-naphthalene dihydrodiol dehydrogenase was demonstrated in Escherichia coli cells. narB encodes a putative protein of 271 amino acids and shares 39% amino acid identity with the cis-naphthalene dihydrodiol dehydrogenase from Pseudomonas putida G7. Comparison of NarB with some putative cis-dihydrodiol dehydrogenases from Rhodococcus species revealed significant differences between these proteins. NarB together with two other proteins forms a new group of cis-dihydrodiol dehydrogenases.


Assuntos
Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Naftalenos/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Oxirredutases , Rhodococcus/enzimologia , Rhodococcus/genética , Oxirredutases do Álcool/química , Sequência de Aminoácidos , Biodegradação Ambiental , Fracionamento Celular , Clonagem Molecular , Meios de Cultura , Genes Bacterianos , Dados de Sequência Molecular , Filogenia , Rhodococcus/crescimento & desenvolvimento , Alinhamento de Sequência , Análise de Sequência de DNA
14.
Antonie Van Leeuwenhoek ; 78(3-4): 341-52, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11386357

RESUMO

Analysis of the bacterial population of soil surface samples from a creosote-contaminated site showed that up to 50% of the culturable micro-organisms detected were able to utilise a mixture of cresols. From fifty different microbial isolates fourteen that could utilise more than one cresol isomer were selected and identified by 16S rRNA analysis. Eight isolates were Rhodococcus strains and six were Pseudomonas strains. In general, the Rhodococcus strains exhibited a broader growth substrate range than the Pseudomonas strains. The distribution of various extradiol dioxygenase (edo) genes, previously associated with aromatic compound degradation in rhodococci, was determined for the Rhodococcus strains by PCR detection and Southern-blot hybridization. One strain, Rhodococcus sp. II exhibited the broadest growth substrate range and possessed five different edo genes. Gene disruption experiments indicated that two genes (edoC and edoD) were associated with isopropylbenzene and naphthalene catabolism respectively. The other Rhodococcus strains also possessed some of the edo genes and one (edoB) was present in all of the Rhodococcus strains analysed. None of the rhodococcal edo genes analysed were present in the Pseudomonas strains isolated from the site. It was concluded that individual strains of Rhodococcus possess a wide degradative ability and may be very important in the degradation of complex mixtures of substrates found in creosote.


Assuntos
Creosoto , Cresóis/metabolismo , Variação Genética , Oxigenases/genética , Pseudomonas/enzimologia , Pseudomonas/genética , Rhodococcus/enzimologia , Rhodococcus/genética , Poluentes do Solo , Sequência de Bases , Biodegradação Ambiental , Primers do DNA , Oxigenases/metabolismo , Plasmídeos , Reação em Cadeia da Polimerase , Pseudomonas/classificação , Rhodococcus/classificação , Microbiologia do Solo
15.
Appl Environ Microbiol ; 65(10): 4301-12, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10508052

RESUMO

A novel dehalogenating/transhalogenating enzyme, halomethane:bisulfide/halide ion methyltransferase, has been isolated from the facultatively methylotrophic bacterium strain CC495, which uses chloromethane (CH(3)Cl) as the sole carbon source. Purification of the enzyme to homogeneity was achieved in high yield by anion-exchange chromatography and gel filtration. The methyltransferase was composed of a 67-kDa protein with a corrinoid-bound cobalt atom. The purified enzyme was inactive but was activated by preincubation with 5 mM dithiothreitol and 0.5 mM CH(3)Cl; then it catalyzed methyl transfer from CH(3)Cl, CH(3)Br, or CH(3)I to the following acceptor ions (in order of decreasing efficacy): I(-), HS(-), Cl(-), Br(-), NO(2)(-), CN(-), and SCN(-). Spectral analysis indicated that cobalt in the native enzyme existed as cob(II)alamin, which upon activation was reduced to the cob(I)alamin state and then was oxidized to methyl cob(III)alamin. During catalysis, the enzyme shuttles between the methyl cob(III)alamin and cob(I)alamin states, being alternately demethylated by the acceptor ion and remethylated by halomethane. Mechanistically the methyltransferase shows features in common with cobalamin-dependent methionine synthase from Escherichia coli. However, the failure of specific inhibitors of methionine synthase such as propyl iodide, N(2)O, and Hg(2+) to affect the methyltransferase suggests significant differences. During CH(3)Cl degradation by strain CC495, the physiological acceptor ion for the enzyme is probably HS(-), a hypothesis supported by the detection in cell extracts of methanethiol oxidase and formaldehyde dehydrogenase activities which provide a metabolic route to formate. 16S rRNA sequence analysis indicated that strain CC495 clusters with Rhizobium spp. in the alpha subdivision of the Proteobacteria and is closely related to strain IMB-1, a recently isolated CH(3)Br-degrading bacterium (T. L. Connell Hancock, A. M. Costello, M. E. Lidstrom, and R. S. Oremland, Appl. Environ. Microbiol. 64:2899-2905, 1998). The presence of this methyltransferase in bacterial populations in soil and sediments, if widespread, has important environmental implications.


Assuntos
Cloreto de Metila/metabolismo , Methylobacterium/enzimologia , Metiltransferases/isolamento & purificação , Sequência de Aminoácidos , Ativação Enzimática , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Cinética , Metiltransferases/metabolismo , Dados de Sequência Molecular , Peso Molecular , Sulfetos/metabolismo , Temperatura
16.
J Bacteriol ; 181(19): 6200-4, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10498739

RESUMO

We report here the characterization of the catalytic component (ISP(NAR)) of a new naphthalene dioxygenase from Rhodococcus sp. strain NCIMB12038. The genes encoding the two subunits of ISP(NAR) are not homologous to their previously characterized counterparts in Pseudomonas. The deduced amino acid sequences have only 33 and 29% identity with the corresponding subunits in Pseudomonas putida NCIB 9816-4, for which the tertiary structure has been reported.


Assuntos
Complexo III da Cadeia de Transporte de Elétrons , Proteínas Ferro-Enxofre/genética , Complexos Multienzimáticos/genética , Oxigenases/genética , Rhodococcus/genética , Sequência de Aminoácidos , Sequência Conservada , Dioxigenases , Dados de Sequência Molecular , Rhodococcus/enzimologia , Homologia de Sequência de Aminoácidos
17.
Appl Environ Microbiol ; 65(3): 1335-9, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10049904

RESUMO

The biotransformation of the polycyclic aromatic hydrocarbons (PAHs) naphthalene and phenanthrene was investigated by using two dioxygenase-expressing bacteria, Pseudomonas sp. strain 9816/11 and Sphingomonas yanoikuyae B8/36, under conditions which facilitate mass-transfer limited substrate oxidation. Both of these strains are mutants that accumulate cis-dihydrodiol metabolites under the reaction conditions used. The effects of the nonpolar solvent 2,2,4, 4,6,8,8-heptamethylnonane (HMN) and the nonionic surfactant Triton X-100 on the rate of accumulation of these metabolites were determined. HMN increased the rate of accumulation of metabolites for both microorganisms, with both substrates. The enhancement effect was most noticeable with phenanthrene, which has a lower aqueous solubility than naphthalene. Triton X-100 increased the rate of oxidation of the PAHs with strain 9816/11 with the effect being most noticeable when phenanthrene was used as a substrate. However, the surfactant inhibited the biotransformation of both naphthalene and phenanthrene with strain B8/36 under the same conditions. The observation that a nonionic surfactant could have such contrasting effects on PAH oxidation by different bacteria, which are known to be important for the degradation of these compounds in the environment, may explain why previous research on the application of the surfactants to PAH bioremediation has yielded inconclusive results. The surfactant inhibited growth of the wild-type strain S. yanoikuyae B1 on aromatic compounds but did not inhibit B8/36 dioxygenase enzyme activity in vitro.


Assuntos
Bacilos e Cocos Aeróbios Gram-Negativos/metabolismo , Hidrocarbonetos Aromáticos/metabolismo , Pseudomonas/metabolismo , Microbiologia do Solo , Tensoativos/farmacologia , Biodegradação Ambiental , Bacilos e Cocos Aeróbios Gram-Negativos/enzimologia , Naftalenos/metabolismo , Octoxinol/farmacologia , Oxigenases/metabolismo , Fenantrenos/metabolismo , Pseudomonas/enzimologia , Pseudomonas/crescimento & desenvolvimento
18.
Appl Environ Microbiol ; 64(8): 2931-6, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9687453

RESUMO

The gram-negative bacterium Pseudomonas cichorii 170, isolated from soil that was repeatedly treated with the nematocide 1, 3-dichloropropene, could utilize low concentrations of 1, 3-dichloropropene as a sole carbon and energy source. Strain 170 was also able to grow on 3-chloroallyl alcohol, 3-chloroacrylic acid, and several 1-halo-n-alkanes. This organism produced at least three different dehalogenases: a hydrolytic haloalkane dehalogenase specific for haloalkanes and two 3-chloroacrylic acid dehalogenases, one specific for cis-3-chloroacrylic acid and the other specific for trans-3-chloroacrylic acid. The haloalkane dehalogenase and the trans-3-chloroacrylic acid dehalogenase were expressed constitutively, whereas the cis-3-chloroacrylic acid dehalogenase was inducible. The presence of these enzymes indicates that 1, 3-dichloropropene is hydrolyzed to 3-chloroallyl alcohol, which is oxidized in two steps to 3-chloroacrylic acid. The latter compound is then dehalogenated, probably forming malonic acid semialdehyde. The haloalkane dehalogenase gene, which is involved in the conversion of 1,3-dichloropropene to 3-chloroallyl alcohol, was cloned and sequenced, and this gene turned out to be identical to the previously studied dhaA gene of the gram-positive bacterium Rhodococcus rhodochrous NCIMB13064. Mutants resistant to the suicide substrate 1,2-dibromoethane lacked haloalkane dehalogenase activity and therefore could not utilize haloalkanes for growth. PCR analysis showed that these mutants had lost at least part of the dhaA gene.


Assuntos
Compostos Alílicos/metabolismo , Hidrolases/metabolismo , Inseticidas/metabolismo , Pseudomonas/metabolismo , Alcanos/metabolismo , Biodegradação Ambiental , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Genes Bacterianos , Hidrocarbonetos Clorados , Hidrolases/genética , Hidrolases/isolamento & purificação , Mutação , Plasmídeos/genética , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , Microbiologia do Solo
19.
Antonie Van Leeuwenhoek ; 74(1-3): 133-53, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-10068796

RESUMO

Eubacteria of the genus Rhodococcus are a diverse group of microorganisms commonly found in many environmental niches from soils to seawaters and as plant and animal pathogens. They exhibit a remarkable ability to degrade many organic compounds and their economic importance is becoming increasingly apparent. Although their genetic organisation is still far from understood, there have been many advances in recent years. Reviewed here is the current knowledge of rhodococci relating to gene transfer, recombination, plasmid replication and functions, cloning vectors and reporter genes, gene expression and its control, bacteriophages, insertion sequences and genomic rearrangements. Further fundamental studies of Rhodococcus genetics and the application of genetic techniques to the these bacteria will be needed for their continued biotechnological exploitation.


Assuntos
Rhodococcus/genética , Biotecnologia , Regulação Bacteriana da Expressão Gênica , Técnicas de Transferência de Genes , Genes Reporter , Vetores Genéticos , Plasmídeos , Recombinação Genética
20.
Plasmid ; 38(1): 61-9, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9281496

RESUMO

Cryptic plasmids were found in Rhodococcus rhodochrous NCIMB13064 derivatives which had lost the ability to utilize short-chain 1-chloroalkanes (chain length C3-C10) and had acquired the ability to degrade naphthalene. The reversions of these derivatives to the original phenotype were accompanied by the loss of the cryptic plasmids. The 4969-bp pKA22 plasmid was cloned in Escherichia coli and sequenced. This plasmid encodes a putative 33,200-Da protein which contains motifs typical of theta replicase proteins and shows a high degree of similarity to a putative theta replicase from Brevibacterium linens plasmid pRBL1 and to a putative protein encoded by ORF1 of the plasmid pAL5000 from Mycobacterium fortuitum. Two sets of long direct repeats were found in pKA22 which may be involved in the replication of the plasmid and recombination processes.


Assuntos
Naftalenos/metabolismo , Plasmídeos/genética , Rhodococcus/genética , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Sequência de Bases , Biodegradação Ambiental , Clonagem Molecular , Replicação do DNA/genética , DNA Bacteriano/genética , DNA Polimerase Dirigida por DNA/genética , Hidrocarbonetos Clorados/metabolismo , Dados de Sequência Molecular , Fases de Leitura Aberta , Fenótipo , Recombinação Genética/genética , Sequências Repetitivas de Ácido Nucleico , Rhodococcus/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
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