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At least 73 records · Page 4Linked to original sources
PubMed2006

Growth stimulatory effect of Ochrobactrum intermedium and Bacillus cereus on Vigna radiata plants.

AIMS: This study assessed the plant growth-promoting ability of the bacterial strains Ochrobactrum intermedium (isolate CrT-1) and Bacillus cereus (isolate S-6). METHODS AND RESULTS: Two chromium resistant bacterial strains isolated from chromium-contaminated wastewater and soils were identified as O. intermedium CrT-1 and B. cereus S-6. These strains were inoculated on seeds of mungbean Vigna radiata var NM-92, which were germinated and grown under chromate salts (300 microg ml(-1) of CrCl(3)or K(2)CrO(4)). The data show that Cr(VI) was more toxic because of its better availability to plants roots when compared with Cr(III). The major part of Cr(VI) supplied to the seedlings was reduced to Cr(III) in the rhizosphere by the bacterial strains, thus lowering the toxicity of chromium to seedlings. CONCLUSIONS: Strains have significant Cr(VI) resistance and reduction potential and have ability to enhance mungbean plant growth under chromium stress. SIGNIFICANCE AND IMPACT OF THE STUDY: These strains could be utilized for the growth of economically important cash crops as well as for the bioremediation of chromium-polluted soils.

Bacillus cereus↗
PubMed2001

Molecular characterization of chromosomal class C beta-lactamase and its regulatory gene in Ochrobactrum anthropi.

Ochrobactrum anthropi, formerly known as CDC group Vd, is an oxidase-producing, gram-negative, obligately aerobic, non-lactose-fermenting bacillus of low virulence that occasionally causes human infections. It is highly resistant to all beta-lactams except imipenem. A clinical isolate, SLO74, and six reference strains were tested. MICs of penicillins, aztreonam, and most cephalosporins tested, including cefotaxime and ceftazidime, were >128 microg/ml and of cefepime were 64 to >128 microg/ml. Clavulanic acid was ineffective and tazobactam had a weak effect in association with piperacillin. Two genes, ampR and ampC, were cloned by inserting restriction fragments of genomic DNA from the clinical strain O. anthropi SLO74 into pBK-CMV to give the recombinant plasmid pBK-OA1. The pattern of resistance to beta-lactams of this clone was similar to that of the parental strain, except for its resistance to cefepime (MIC, 0.5 ,micro/ml). The deduced amino acid sequence of the AmpC beta-lactamase (pI, 8.9) was only 41 to 52% identical to the sequence of other chromosomally encoded and plasmid-encoded class C beta-lactamases. The kinetic properties of this beta-lactamase were typical for this class of beta-lactamases. Upstream from the ampC gene, the ampR gene encodes a protein with a sequence that is 46 to 62% identical to those of other AmpR proteins and with an amino-terminal DNA-binding domain typical of transcriptional activators of the Lys-R family. The deduced amino acid sequences of the ampC genes of the six reference strains were 96 to 99% identical to the sequence of the clinical strain. The beta-lactamase characterized from strain SLO74 was named OCH-1 (gene, bla(OCH-I)).

Amino Acid Sequence↗
PubMed2006

Establishment of a gene expression system in Ochrobactrum anthropi.

Genetic studies of Ochrobactrum anthropi are hindered by the lack of a suitable gene expression system. We constructed a set of vectors containing several promoters and a His tag fusion in the N terminus to facilitate protein detection and purification. The new vectors should significantly enhance the genetic manipulation and characterization of O. anthropi.

Gene Expression↗
PubMed2001

Purification, characterization, and gene cloning of purine nucleosidase from Ochrobactrum anthropi.

A bacterium, Ochrobactrum anthropi, produced a large amount of a nucleosidase when cultivated with purine nucleosides. The nucleosidase was purified to homogeneity. The enzyme has a molecular weight of about 170,000 and consists of four identical subunits. It specifically catalyzes the irreversible N-riboside hydrolysis of purine nucleosides, the K(m) values being 11.8 to 56.3 microM. The optimal activity temperature and pH were 50 degrees C and pH 4.5 to 6.5, respectively. Pyrimidine nucleosides, purine and pyrimidine nucleotides, NAD, NADP, and nicotinamide mononucleotide are not hydrolyzed by the enzyme. The purine nucleoside hydrolyzing activity of the enzyme was inhibited (mixed inhibition) by pyrimidine nucleosides, with K(i) and K(i)' values of 0.455 to 11.2 microM. Metal ion chelators inhibited activity, and the addition of Zn(2+) or Co(2+) restored activity. A 1.5-kb DNA fragment, which contains the open reading frame encoding the nucleosidase, was cloned, sequenced, and expressed in Escherichia coli. The deduced 363-amino-acid sequence including a 22-residue leader peptide is in agreement with the enzyme molecular mass and the amino acid sequences of NH(2)-terminal and internal peptides, and the enzyme is homologous to known nucleosidases from protozoan parasites. The amino acid residues forming the catalytic site and involved in binding with metal ions are well conserved in these nucleosidases.

Amino Acid Sequence↗
PubMed2005

L-selective amidase with extremely broad substrate specificity from Ochrobactrum anthropi NCIMB 40321.

An industrially attractive L-specific amidase was purified to homogeneity from Ochrobactrum anthropi NCIMB 40321 wild-type cells. The purified amidase displayed maximum initial activity between pH 6 and 8.5 and was fully stable for at least 1 h up to 60 degrees C. The purified enzyme was strongly inhibited by the metal-chelating compounds EDTA and 1,10-phenanthroline. The activity of the EDTA-treated enzyme could be restored by the addition of Zn2+ (to 80%), Mn2+ (to 400%), and Mg2+ (to 560%). Serine and cysteine protease inhibitors did not influence the purified amidase. This enzyme displayed activity toward a broad range of substrates consisting of alpha-hydrogen- and (bulky) alpha,alpha-disubstituted alpha-amino acid amides, alpha-hydroxy acid amides, and alpha-N-hydroxyamino acid amides. In all cases, only the L-enantiomer was hydrolyzed, resulting in E values of more than 150. Simple aliphatic amides, beta-amino and beta-hydroxy acid amides, and dipeptides were not converted. The gene encoding this L-amidase was cloned via reverse genetics. It encodes a polypeptide of 314 amino acids with a calculated molecular weight of 33,870. Since the native enzyme has a molecular mass of about 66 kDa, it most likely has a homodimeric structure. The deduced amino acid sequence showed homology to a few other stereoselective amidases and the acetamidase/formamidase family of proteins (Pfam FmdA_AmdA). Subcloning of the gene in expression vector pTrc99A enabled efficient heterologous expression in Escherichia coli. Altogether, this amidase has a unique set of properties for application in the fine-chemicals industry.

Amidohydrolases↗
PubMed2002

Recombinant Ochrobactrum anthropi expressing Brucella abortus Cu,Zn superoxide dismutase protects mice against B. abortus infection only after switching of immune responses to Th1 type.

The members of the genus Brucella are gram-negative, facultatively intracellular bacterial pathogens that cause brucellosis in many animal species and humans. Although live, attenuated vaccines are available to protect several animal species from the disease, there is no safe and effective vaccine for human use. Here we report that a bacterium that is closely related to Brucella species, Ochrobactrum anthropi, can be used as a vaccine vector for the delivery of Brucella antigens to mice, leading to the elicitation of protective immunity against brucellosis. Brucella abortus Cu,Zn superoxide dismutase (SOD), a protective Brucella antigen, was expressed in large amounts in O. anthropi strain 49237 by use of the broad-host-range plasmid pBBR1MCS. Neither O. anthropi strain 49237 nor the recombinant O. anthropi strain 49237SOD, expressing B. abortus Cu,Zn SOD, provided protection against virulent Brucella infection in mice. Analysis of immune responses indicated that strains 49237 and 49237SOD stimulated a mix of Th1 and Th2 type responses in the mice. After the immune response was switched to a Th1-biased response by addition of oligonucleotides containing unmethylated CpG motifs, both O. anthropi strain 49237 and the recombinant O. anthropi strain 49237SOD induced protection in mice. However, the protection conferred by strain 49237SOD was significantly better than that induced by the parental strain, 49237.

Animals↗
PubMed2003

Septic shock caused by Ochrobactrum anthropi in an otherwise healthy host.

Reported is a case of life-threatening septic shock that occurred in an otherwise healthy host after administration of a peripheral venous infusion of a solution contaminated with Ochrobactrum anthropi, an unusual human pathogen. The rapid onset of shock may have been due to a large inoculum caused by nonsterile practices at the time of reconstitution.

Adult↗
PubMed2004

Prosthetic mitral valve endocarditis due to Ochrobactrum anthropi: case report.

We describe a case of infective endocarditis in a prosthetic mitral valve due to Ochrobactrum anthropi. Although O. anthropi is an emerging pathogen in immunocompromised patients, infections with the bacterium have very rarely been documented in healthy hosts, and endocarditis is rare. To our knowledge, only two cases of O. anthropi endocarditis have been reported in the medical literature.

Aged↗
PubMed2006

Pelvic abscess due to Ochrobactrum intermedium [corrected] in an immunocompetent host: case report and review of the literature.

Ochrobactrum intermedium [corrected] infection is rare in humans and is generally associated with immunocompromised hosts with indwelling foreign bodies. We report a case of pelvic abscess with O. intermedium [corrected] after a routine appendectomy in an immunocompetent patient and review the literature on O. intermedium [corrected] infection in patients with normal immune function.

Abscess↗
PubMed2000

Modulation of the glutathione S-transferase in Ochrobactrum anthropi: function of xenobiotic substrates and other forms of stress.

The gluthathione S-transferase gene of the atrazine-degrading bacterium Ochrobactrum anthropi (OaGST) encodes a single-subunit polypeptide of 201 amino acid residues (Favaloro et al. 1998, Biochem. J. 335, 573-579). RNA blot analysis showed that the gene is transcribed into an mRNA of about 800 nucleotides, indicating a monocistronic transcription of the OaGST gene. The modulation of OaGST in this bacterium, in the presence of different stimulants, was investigated. The level of expression of OaGST was detected both by measuring the mRNA level and by immunoblotting experiments. OaGST is a constitutive enzyme which is also inducible by several stimulants. In fact, atrazine caused an increase in the expression of OaGST even at concentrations which had no effect on growth rates of the bacteria. Moreover, the presence of other aromatic substrates of this bacterium, such as phenol and chlorophenols, leads to a marked enhancement in OaGST expression. In this case, the expression of OaGST was related to growth inhibition and membrane damage caused by these hydrophobic compounds, and to the adaptive responses of the cell membranes. On the other hand, toluene and xylene, two aromatic compounds not degradable by this bacterium, did not induce the OaGST expression. The same was observed for other stress conditions such as low pH, heat shock, hydrogen peroxide, osmotic stress, starvation, the presence of aliphatic alcohols or heavy metals. These results suggest a co-regulation of the OaGST gene by the catabolic pathways of phenols and chlorophenols in this bacterium. Therefore, OaGST could function as a detoxifying agent within the catabolism of these xenobiotics.

Glutathione Transferase↗
PubMed2000

[Isolation of moniliformin-degrading bacterium Ochrobactrum sp. and analysis of its functional properties].

A moniliformin(MON)-degrading bacterium strain, named as Y21-2, was isolated from the mycotoxin-contaminated soil from Heilongjiang Province by the enrichment microculture technique. This strain can grow with MON as its sole carbon and energy source. In the minimal medium with 500 micrograms/mL MON, the number of cells increased from 10(7) to 10(10). Traditional taxonomy, assays of its G + C content and 16S rDNA sequence homology identified Y21-2 as Rhizobiaceae, Ochrobactrum sp. Resting cell suspensions prepared from induced Y21-2 can degrade MON with great speed, which also suggested the existence of enzymes committed to MON degradation in the cell.

Biodegradation, Environmental↗
PubMed2006

Ochrobactrum anthropi endocarditis and septic shock in a patient with no prosthetic valve or rheumatic heart disease: case report and review of the literature.

Although Ochrobactrum anthropi is an opportunistic pathogen in immunocompromised patients, it is increasingly being recognized to be a causative agent in healthy hosts. In this paper, we report a case of O. anthropi endocarditis and septic shock in a patient who had no prosthetic valve or rheumatic heart disease, in contrast to previous reports.

Adult↗
PubMed1998

Degradation of various chlorophenols under alkaline conditions by gram-negative bacteria closely related to Ochrobactrum anthropi.

From concrete debris of a demolished herbicide production plant several Gram-negative bacterial strains were isolated, which exhibit metabolic capabilities for the degradation of 2,4-dichlorophenol (DCP)l), 4-chloro-2-methylphenol (MCP) and 4-chlorophenol (4-CP), while 2-chlorophenol (2-CP) was degraded at a slower rate. Degradative activity was inducible and was impeded by adding of 100 mg/l of chloramphenicol to growing cultures. The strains displayed alkaliphilic properties with optimum DCP/MCP degradation at pH values around 8.5-9.5; activity was observed up to pH values of 11. Degradation was most likely complete according to chlorine balances; formation of intermediary products was observed with MCP some time. Specific activity of up to 380 mumol/h.g dry mass was found within the concentration range of 10-20 mg/l DCP; higher concentrations retarded the activity with complete inhibition at 200-400 mg/l. Some of the strains carry plasmids whose presence was not unambiguously correlated to the degradative properties. Ribotyping revealed a high degree of relationship between the strains. Preliminary taxonomic investigations showed close relationship to Ochrobactrum anthropi.

Anti-Bacterial Agents↗
PubMed1997

Proteomic 'contigs' of Ochrobactrum anthropi, application of extensive pH gradients.

The most extensive linear pH gradients yet employed in combination with two-dimensional gel electrophoresis are described, along with their application in proteome analysis. A significant proportion of the protein compliment of bacterial species is believed to be accessible using an extended linear pH gradient of 2.3 to 11.0. Protein standards with predicted isoelectric points (pI) ranging from 3.24 to 9.56 were used to confirm focusing positions with respect to the immobilised pH gradients (IPG) prior to mapping studies of Ochrobactrum anthropi. Multiple gel images were used to construct contiguous windows of protein expression ('proteomic contigs') within 18 cm pH gradients 2.3-5, 4-7, and 6-11 in conjunction with 15% T and 7.5% T acrylamide gels, the latter being used to resolve higher molecular weight (M(r)) proteins. Each IPG had a 5 cm region of similar pH gradient overlap at pH 4-5 and pH 6-7 that was used to construct an image of protein expression characteristic of whole cell lysates. This is reminiscent of genomic sequencing initiatives whereby portions are combined to form a contiguous picture of the whole. The protein maps obtained demonstrated a means of resolving the many tens of thousands of cellular proteins likely to occur in eukaryotic systems, but also highlighted the need to further optimise protein extraction, equilibration buffers, and separation conditions of higher M(r) proteins occurring at extreme pI. Theoretical 2-D protein maps were constructed for five organisms for which the total DNA sequence is now available. In all cases, higher M(r) acidic and basic proteins were shown to be common.

Bacterial Proteins↗
PubMed2001

An Ochrobactrum anthropi gene conferring paraquat resistance to the heterologous host Escherichia coli.

A new gene, pqrA, conferring paraquat resistance to the heterologous host Escherichia coli, from a chromosomal DNA library of Ochrobactrum anthropi JW2, was cloned and analyzed. Cells of E. coli transformed with a plasmid carrying the pqrA gene showed elevated resistance to paraquat, but not to hydrogen peroxide. The predicted amino acid sequence of the PqrA polypeptide showed 71% identity with mll7495 hypothetical membrane protein in Mesorhizobium loti, 49% identity with PA2269 protein in Pseudomonas aeruginosa, and significant identity with other previously reported drug transport proteins. The hydropathy pattern of the PqrA polypeptide showed a significant homology to those of 12-transmembrane-segment (TMS) family export proteins. Immunoblot analysis demonstrated that the PqrA protein found in the membrane protein fraction of O. anthropi JW2 has a molecular mass of 42 kDa. These results suggest that the PqrA protein is a membrane protein that plays an important role in protecting cells against paraquat toxicity.

Amino Acid Sequence↗
PubMed1995

Evaluation of pulsed-field gel electrophoresis and rep-PCR for the epidemiological analysis of Ochrobactrum anthropi strains.

Pulsed-field gel electrophoresis and polymerase chain reaction genome fingerprinting based on repetitive chromosomal sequences (rep-PCR) were used for typing 14 strains of Ochrobactrum anthropi. Six strains isolated during an outbreak of bacteraemia in patients who had received a contaminated rabbit anti-thymocyte globulin gave identical patterns by both techniques. Different patterns were found in sporadic and reference strains, except for one clinical isolate received from another hospital that showed the same pattern as the epidemic clone. This patient had also received rabbit anti-thymocyte globulin from the same source at the time of the outbreak. This study illustrates the advantages of genetic typing methods in terms of high typeability and discriminating power, even for rare pathogens. Furthermore, it highlights the need for interhospital communication for effective identification of common sources of outbreaks related to intrinsic drug contamination.

Alcaligenes↗
PubMedDate not supplied

Ochrobactrum anthropi bacteremia: report of four cases and short review.

Ochrobactrum anthropi, formerly "Achromobacter" CDC group Vd, is a nonfermentative, nonfastidious gram-negative bacillus, that only recently has been given attention as a potential human pathogen. Over a 2-year period, we observed four patients with multiple blood cultures that were positive for the organism. The patients had acute leukemia as underlying disease, and presented with clinical and microbiologic features consistent with catheter-related bacteremia. In three of the patients the infection initially appeared to be unrelated to chemotherapy-associated profound neutropenia and occurred early after, or was the reason for, hospital admission. The antimicrobial susceptibility of the isolates varied: unlike previously reported cases, resistance in some of our isolates included aminoglycosides, newer fluoroquinolones, and trimethoprim-sulfamethoxazole. Despite in vitro susceptibility to imipenem in initial isolates, treatment of two patients with this agent obviously failed to eradicate the organism, and the patients either relapsed with bacteremia shortly after discontinuation of treatment or remained persistently febrile and bacteremic. O. anthropi appears to be increasingly recognized as a human opportunist pathogen associated with intravascular catheters and unpredictable multiple antibiotic resistance.

Adult↗