Project description:The clinical picture of Ochrobactrum anthropi infection is not well described because the infection is rare in humans and identification of the pathogen is difficult. We present a case of O. anthropi bacteremia that was initially misidentified as Ralstonia paucula and later identified by 16S rRNA sequencing and recA analysis.
Project description:ITALIC! Ochrobactrum anthropiFRAF13 was isolated from farmland soil in Jersey Village, Texas. FRAF13 is a bacterial microorganism with broad antibiotic resistance that possesses a number of metal-dependent ?-lactam enzymes with secondary phosphotriesterase activity that can initiate the breakdown of organophosphate compounds.
Project description: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.
Project description:Ochrobactrum anthropi is an occasional cause of nosocomial infections; however, interest in the organism lies in its phylogenetic proximity to the genus Brucella. Here, we present the 4.9-Mb finished genome of Ochrobactrum anthropi ATCC 49687, most commonly used as an exclusionary reference organism.
Project description:?-Transaminases display complicated inhibitions by ketone products and both enantiomers of amine substrates. Here, we report the first example of ?-transaminase devoid of such inhibitions. Owing to the lack of enzyme inhibitions, the ?-transaminase from Ochrobactrum anthropi enabled efficient kinetic resolution of ?-methylbenzylamine (500 mM) even without product removal.
Project description: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.
Project description:Ochrobactrum anthropi is a gram-negative rod belonging to the Brucellaceae family, able to colonize a variety of environments, and actually reported as a human opportunistic pathogen. Despite its low virulence, the bacterium causes a growing number of hospital-acquired infections mainly, but not exclusively, in immunocompromised patients. The aim of this study was to obtain an overview of the global proteome changes occurring in O. anthropi in response to different growth temperatures, in order to achieve a major understanding of the mechanisms by which the bacterium adapts to different habitats and to identify some potential virulence factors. Combined quantitative mass spectrometry-based proteomics and bioinformatics approaches were carried out on two O. anthropi strains grown at temperatures miming soil/plants habitat (25 C) and human host environment (37 C), respectively. Proteomic analysis led to the identification of over 150 differentially expressed proteins in both strains, out of over 1200 total protein identifications. Among them, proteins responsible for heat shock response (DnaK, GrpE), motility (FliC, FlgG, FlgE), and putative virulence factors (TolB) were identified. The study represents the first quantitative proteomic analysis of O. anthropi performed by high-resolution quantitative mass spectrometry.
Project description:Most studies of bacterial denitrification have used nitrate (NO3-) as the first electron acceptor, whereas relatively less is understood about nitrite (NO2-) denitrification. We isolated novel bacteria that proliferated in the presence of high levels of NO2- (72 mM). Strain YD50.2, among several isolates, was taxonomically positioned within the alpha subclass of Proteobacteria and identified as Ochrobactrum anthropi YD50.2. This strain denitrified NO2-, as well as NO3-. The gene clusters for denitrification (nar, nir, nor, and nos) were cloned from O. anthropi YD50.2, in which the nir and nor operons were linked. We confirmed that nirK in the nir-nor operon produced a functional NO2- reductase containing copper that was involved in bacterial NO2- reduction. The strain denitrified up to 40 mM NO2- to dinitrogen under anaerobic conditions in which other denitrifiers or NO3- reducers such as Pseudomonas aeruginosa and Ralstonia eutropha and nitrate-respiring Escherichia coli neither proliferated nor reduced NO2-. Under nondenitrifying aerobic conditions, O. anthropi YD50.2 and its type strain ATCC 49188(T) proliferated even in the presence of higher levels of NO2- (100 mM), and both were considerably more resistant to acidic NO2- than were the other strains noted above. These results indicated that O. anthropi YD50.2 is a novel denitrifier that has evolved reactive nitrogen oxide tolerance mechanisms.
Project description:Azoxystrobin is one of the most popular strobilurin fungicides, widely used in agricultural fields for decades.Extensive use of azoxystrobin poses a major threat to ecosystems. However, little is known about the kinetics and mechanism of azoxystrobin biodegradation. The present study reports a newly isolated bacterial strain, Ochrobactrum anthropi SH14, utilizing azoxystrobin as a sole carbon source, was isolated from contaminated soils. Strain SH14 degraded 86.3% of azoxystrobin (50 μg·mL-1) in a mineral salt medium within five days. Maximum specific degradation rate (qmax), half-saturation constant (Ks), and inhibition constant (Ki) were noted as 0.6122 d-1, 6.8291 μg·mL-1, and 188.4680 μg·mL-1, respectively.Conditions for strain SH14 based azoxystrobin degradation were optimized by response surface methodology. Optimum degradation was determined to be 30.2 °C, pH 7.9, and 1.1 × 107 CFU·mL-1 of inoculum. Strain SH14 degraded azoxystrobin via a novel metabolic pathway with the formation of N-(4,6-dimethoxypyrimidin-2-yl)-acetamide,2-amino-4-(4-chlorophenyl)-3-cyano-5,6-dimethyl-pyridine, and 3-quinolinecarboxylic acid,6,8-difluoro-4-hydroxy-ethyl ester as the main intermediate products, which were further transformed without any persistent accumulative product. This is the first report of azoxystrobin degradation pathway in a microorganism. Strain SH14 also degraded other strobilurin fungicides, including kresoxim-methyl (89.4%), pyraclostrobin (88.5%), trifloxystrobin (78.7%), picoxystrobin (76.6%), and fluoxastrobin (57.2%) by following first-order kinetic model. Bioaugmentation of azoxystrobin-contaminated soils with strain SH14 remarkably enhanced the degradation of azoxystrobin, and its half-life was substantially reduced by 95.7 and 65.6 days in sterile and non-sterile soils, respectively, in comparison with the controls without strain SH14. The study presents O. anthropi SH14 for enhanced biodegradation of azoxystrobin and elaborates on the metabolic pathways to eliminate its residual toxicity from the environment.