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PubMed1990

In vitro susceptibility of selected veterinary bacterial pathogens to ciprofloxacin, enrofloxacin and norfloxacin.

The minimum inhibitory concentrations (MIC) of ciprofloxacin, enrofloxacin, and norfloxacin were tested for approximately ten clinical isolates of each of Actinobacillus pleuropneumoniae, Actinobacillus suis, Actinomyces pyogenes, Corynebacterium pseudotuberculosis, Erysipelothrix rhusiopathiae, Haemophilus parasuis, Haemophilus somnus, Pasteurella haemolytica, Pasteurella multocida, Rhodococcus equi, Streptococcus equi, Streptococcus suis and Streptococcus zooepidemicus. Ciprofloxacin and enrofloxacin had similar activity and were more active than norfloxacin. All isolates had an MIC of 1.0 microgram/mL or less for ciprofloxacin and enrofloxacin, and these drugs had particularly marked activity against the gram-negative bacteria tested.

Actinobacillus↗
PubMed1988

Molecular-genetic evidence for the relationship of Mycobacterium leprae to slow-growing pathogenic mycobacteria.

A total of 1170 nucleotides of the 16S rRNA from Mycobacterium leprae were compared to the homologous regions of M. tuberculosis, M. bovis Vallée, M. avium, M. scrofulaceum, M. phlei, M. fortuitum and one representative each of the genera Corynebacterium, Nocardia, and Rhodococcus. Homology values were calculated and a phylogenetic tree was constructed from the evolutionary distance values. Despite differences in DNA G + C content and genome size, M. leprae is a true member of the slow-growing pathogenic mycobacteria, branching off intermediate to the other members of this subgroup. Slow- and fast-growing mycobacteria are phylogenetically well separated but constitute an individual branch of the actinomycetes proper. Significant structural variation of certain regions of the 16S rRNA may allow construction of M. leprae-specific probes used for rapid identification.

Animals↗
PubMed1988

Use of a monoclonal antibody in the diagnosis of infection by Dermatophilus congolensis.

A monoclonal antibody (McAb) to Dermatophilus congolensis was produced from murine hybridoma cultures and purified by affinity chromatography. Species specificity was demonstrated using indirect immunofluorescent staining; the McAb was shown to react with 10 D congolensis isolates but not with 10 Nocardia species isolates, a Rhodococcus and a Streptomyces species isolate. The McAb was used to demonstrate D congolensis in clinical material from confirmed bovine and ovine cases and presumptive equine cases of dermatophilosis by indirect immunofluorescent staining.

Actinomycetales↗
PubMedDate not supplied

[Esterase activity of hydrocarbon-oxidizing bacteria].

The activity of esterase was studied in bacteria oxidizing hydrocarbons and belonging to the genera Rhodococcus, Arthrobacter and Pseudomonas. Indophenyl acetate was used as a substrate of the reaction catalysed by the enzyme. Exocellular esterases were not found. Endocellular esterases differed in their activity and thermostability both among the genera and among species of one and the same genus.

Arthrobacter↗
PubMed1986

A novel glycosphingolipid-degrading enzyme cleaves the linkage between the oligosaccharide and ceramide of neutral and acidic glycosphingolipids.

A novel glycosphingolipid-degrading enzyme was found in the cultured supernatant of Rhodococcus sp. G-74-2. It was purified 34.7-fold from the supernatant with 32.2% recovery by ammonium sulfate precipitation followed by Sephadex G-100 chromatography. The enzyme was demonstrated capable of cleaving the linkage between the oligosaccharide and ceramide of various acidic and neutral glycosphingolipids, producing intact oligosaccharides and ceramides. However, it was noted to hardly make any attack on linkages between monosaccharides and ceramides (cerebrosides) or between oligosaccharides and diacylglycerol (glycoglycerolipids). The enzyme preparation was completely free from various exoglycosidases and proteases. Furthermore, it was found to degrade neither N-linked nor O-linked glycoproteins. This enzyme, which is tentatively called endoglycoceramidase, should greatly facilitate the study of glycosphingolipids.

Carbohydrate Sequence↗
PubMed1994

Bacteria and pesticides: a new aspect of interaction--involvement of a new biofactor.

Positively charged hydrophobic pesticides of the dipyridyl family [diquat, paraquat, benzylviologen (BV++), etc.] were shown to provoke accumulation of 2-methylbutane-1,2,3,4-tetraol-2,4- cyclopyrophosphate in the cells Corynebacterium (Brevibacterium) ammoniagenes while neutral dipyridyls were not. Hydrophobicity was also an important factor in this phenomenon. Of the other pesticides tested, only linuron was effective. BV++ also induced biosynthesis of the compound in Rhodococcus rhodochrous, Rh.ruber, Rh.sp. (Nocardia corynebacteroides). These microorganisms as well as most of the previously identified oxidative stress activated producers of this new cyclopyrophosphate were able to synthesize free radical generating compounds. The microorganisms concerned belong mainly to the order Actinomycetales.

2,2'-Dipyridyl↗
PubMed1996

Pulmonary malakoplakia in acquired immunodeficiency syndrome: an ultrastructural study of morphogenesis of Michaelis-Gutmann bodies.

Malakoplakia is an unusual inflammatory reaction to a variety of infections, characterized by the accumulation of macrophages containing the target-like calcospherites, the Michaelis-Gutmann body (MGB). We report three patients with acquired immunodeficiency syndrome with pulmonary malakoplakia associated with Rhodococcus equi infection; two patients were diagnosed at autopsy and one by examination of a transbronchial biopsy specimen. All three patients had pulmonary bacterial cultures and light and electron microscopic examination. The patients were 33-, 41-, and 43-year old men, human immunodeficiency virus-positive for 2, 6, 8 years, respectively. The two patients diagnosed at autopsy had cavitary lesions, and the patient diagnosed by biopsy specimen had nodular lesions on chest radiographs. Histologically, the lungs had well-circumscribed areas of infiltration with benign macrophages with granular cytoplasm, scattered MGBs, and numerous gram-positive coccobacilli. Electron microscopic examination showed intracellular coccobacilli, from 990 X 702 to 972 X 648 nm in diameter, with thick, homogenous cell walls, trilaminar cytoplasmic membranes, and dense cytoplasm with from one to five vacuoles. Electron microscopic studies showed that the bacteria within the pulmonary macrophages had thicker cell walls, less prominent nucleoid areas, and more vacuoles than the bacteria in cultures from the sputum and blood. The mature MGB ultrastructurally had a concentric, trilaminate structure with central mineralized core and was without recognizable bacterial forms. Early MGBs, however, consisted of a circular, electron-dense core containing bacteria, ultrastructurally similar to the R. equi seen in the culture. Pulmonary malakoplakia in patients with the acquired immunodeficiency syndrome might thus represent an acquired macrophage dysfunction of the intracellular digestion of phagocytized bacteria. The bacteria within the macrophages, however, seemed to have thicker cell walls compared with those in culture, and thus might be protected from enzyme digestion. It seems that MGBs are formed around the undigested bacteria as an alternative pathway for bacterial destruction, because R. equi was identified within the cores of early MGBs but not the mature or late stage MGBs.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Allogeneic bone marrow transplantation can restore CD4+ T-lymphocyte count and immune function in idiopathic CD4+ T-lymphocytopenia.

CD4+ T-lymphocytopenia in the absence of HIV infection is a heterogeneous disorder of unknown cause. Here we report a patient with idiopathic CD4+ T-lymphocytopenia, presenting with an opportunistic Rhodococcus equi infection. When aplastic anemia developed subsequently, allogeneic bone marrow transplantation was performed. Complete restoration of immune function was observed. We conclude that allogeneic bone marrow transplantation presents a potentially curative therapy for CD4+ T-lymphocytopenia.

Actinomycetales Infections↗
PubMed1999

A Pentacoordinated Di-N-carboxamido-dithiolato-O-sulfinato-iron(III) Complex Related to the Metal Site of Nitrile Hydratase.

Postcoordination oxidation by dioxygen of one of the thiolate groups in a pentadentate N(2)S(3) ligand results in an iron(III) complex with two N-carboxamido, two thiolato, and one O-sulfinato ligands (see the CAMERON representation). This novel mixed coordination is similar to that determined for the inactive form of the nitrile hydratase from Rhodococcus sp. N-771, but differs by the O versus S binding of the sulfinato ligand.

Journal Article↗
PubMed1998

Utilization of quinate and p-hydroxybenzoate by actinomycetes: key enzymes and taxonomic relevance.

474 strains of the actinomycete genera Streptomyces (including species of the former genera Chainia and Streptoverticillium), Pseudonocardia and Micromonospora were examined for their ability to degrade quinate (Q) and p-hydroxybenzoate (pHB); selected strains were also tested for their capacity to catabolize benzoate (B). Whereas in the case of Q (5-10 g/l of a mineral salts agar medium) the growth response signalizes assimilation, pHB has to be supplied in lower concentration (routinely 0.3 g/l together with small amounts of peptone and yeast extract in liquid broth), and its degradation has to be determined spectrophotometrically. 27% of the streptomycete strains were able to grow with Q, and 57% with pHB. The three strains of "Chainia" that were tested metabolized Q and pHB, but none of the fourty species of "Streptoverticillium" showed this ability. 80% of the 30 strains of Psn. autotrophica grew with Q, and 100% degraded pHB and B. Two of the five Micromonospora strains gave a positive response with pHB, but not with Q.-Toluene treated cells (preincubated with Q, pHB or B, respectively) gave a positive Rothera reaction with protocatechuate or catechol respectively, thus demonstrating that these organisms employed the beta-ketoadipate pathway (orthofission) for the degradation of Q, pHB and B. The assay of five relevant enzymes in cell-free extracts of nine selected organisms showed that in nocardioform actinomycetes (Pseudonocardia, Rhodococcus) all enzymes of the protocatechuate branch of the ketoadipate pathway seem to be induced by beta-ketoadipate as demonstrated here for protocatechuate-3,4-dioxygenase. In contrast, in Streptomyces this enzyme appears to be induced by its substrate, protocatechuate, whereas the regulation of the other enzymes of this pathway remains to be elucidated.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2002

Isolation and characterization of bacteria from crude petroleum oil contaminated soil and their potential to degrade diesel fuel.

Potential hydrocarbon degrader bacteria were isolated from soil samples that have been exposed to crude petroleum oil spills. Bacterial population of these polluted soils showed counts ranging between 9.5 x 10(5) and 237.5 x 10(5) CFU/g soil with 2 different colony types of bacterial strains which have been recovered on the agar plates. Results indicated that longer aged contamination exhibited a greater number of microorganisms. Phenotypic examination of the recovered bacteria revealed that they belong mainly to the genus Pseudomonas, Enterobacter and Acinetobacter. Turbidity, dry weight and physical appearance were used as an indication for the ability of these bacteria to grow on diesel. Action of three different Pseudomonas species, Acinetobacter lowffi, Enterobacter cloacae and Rhodococcus erythropolis on 0.1 % (v/v) diesel was followed at 1, 2, 6 and 12 h. Pseudomonas putida and P. mallei and Enterobacter cloacae indicated a positive reaction; however, Pseudomonas maltophilia and Acinetobacter lowffi showed no effect.

Bacteria↗
PubMed2003

Methyl-beta-cyclodextrin-enhanced solubilization and aerobic biodegradation of polychlorinated biphenyls in two aged-contaminated soils.

The bioremediation of aged polychlorinated biphenyl (PCB)-contaminated soils is adversely affected by the low bioavailability of the pollutants. Randomly methylated-beta-cyclodextrins (RAMEB) were tested as a potential PCB-bioavailability-enhancing agent in the aerobic treatment of two aged-contaminated soils. The soils, contaminated by about 890 and 8500 mg/kg of Aroclor 1260 PCBs, were amended with biphenyl (4 g/kg), inorganic nutrients (to adjust their C:N ratio to 20:1), and variable amounts of RAMEB (0%, 0.5%, or 1.0% [w/w]) and treated in both aerobic 3-L solid-phase reactors and 1.5-L packed-bed loop reactors for 6 months. Notably, significant enhancement of the PCB biodegradation and dechlorination, along with a detectable depletion of the initial soil ecotoxicity, were generally observed in the RAMEB-treated reactors of both soils. RAMEB effects were different in the two soils, depending upon the treatment conditions employed, and generally increased proportionally with the concentration at which RAMEB was applied. RAMEB, which was slowly metabolized by the soil's aerobic microorganisms, was found to markedly enhance the occurrence of the indigenous aerobic, cultivable biphenyl-growing bacteria harboring genes homologous to those of two highly specialized PCB degraders (i.e., bphABC genes of Pseudomonas pseudoalcaligenes KF707 and bphA1A2A3A4BC1 genes of Rhodococcus globerulus P6) and chlorobenzoic acid-degrading bacteria as well as the occurrence of PCBs in the water phase of the soil reactors. These findings indicate that RAMEB enhanced the aerobic bioremediation of the two soils by increasing the bioavailability of PCBs and the occurrence of specialized bacteria in the soil reactors.

Aerobiosis↗
PubMed2005

Aerobic biodegradation of N-nitrosodimethylamine (NDMA) by axenic bacterial strains.

The water contaminant N-nitrosodimethylamine (NDMA) is a probable human carcinogen whose appearance in the environment is related to the release of rocket fuel and to chlorine-based disinfection of water and wastewater. Although this compound has been shown to be biodegradable, there is minimal information about the organisms capable of this degradation, and little is understood of the mechanisms or biochemistry involved. This study shows that bacteria expressing monooxygenase enzymes functionally similar to those demonstrated to degrade NDMA in eukaryotes have the capability to degrade NDMA. Specifically, induction of the soluble methane monooxygenase (sMMO) expressed by Methylosinus trichosporium OB3b, the propane monooxygenase (PMO) enzyme of Mycobacterium vaccae JOB-5, and the toluene 4-monooxygenases found in Ralstonia pickettii PKO1 and Pseudomonas mendocina KR1 resulted in NDMA degradation by these strains. In each of these cases, brief exposure to acetylene gas, a suicide substrate for certain monooxygenases, inhibited the degradation of NDMA. Further, Escherichia coli TG1/pBS(Kan) containing recombinant plasmids derived from the toluene monooxygenases found in strains PKO1 and KR1 mimicked the behavior of the parent strains. In contrast, M. trichosporium OB3b expressing the particulate form of MMO, Burkholderia cepacia G4 expressing the toluene 2-monooxygenase, and Pseudomonas putida mt-2 expressing the toluene sidechain monooxygenase were not capable of NDMA degradation. In addition, bacteria expressing aromatic dioxygenases were not capable of NDMA degradation. Finally, Rhodococcus sp. RR1 exhibited the ability to degrade NDMA by an unidentified, constitutively expressed enzyme that, unlike the confirmed monooxygenases, was not inhibited by acetylene exposure.

Aerobiosis↗
PubMed2005

Analysis of bacterial diversity in acidic pond water and compost after treatment of artificial acid mine drainage for metal removal.

The microbial population of a sludge amended leaf compost material utilized for treatment of artificial acid mine drainage was studied by culture-independent molecular methods. Iron-rich and sulfurous wastewater (artificial acid mine drainage) was circulated through a column bioreactor for 16 months. After 12 months the column was inoculated with a mixed culture from an acidic pond receiving acid mine drainage from a tailings impoundment at a decommissioned site in Kristineberg, North Sweden. Hydrogen sulfide odor and the formation of black precipitates indicated that sulfate-reduction occurred in the column. 16S rDNA gene analysis by denaturing gradient gel electrophoresis, cloning, and sequencing as well as fluorescent in situ hybridization confirmed the presence of microorganisms closely related to sulfate-reducing bacteria and microorganisms from the genera Pseudoxanthmonas, Dechlorosoma, Desulfovibrio, Agrobacterium, Methylocapsa, Rhodococcus, Sulfobacillus, and some unidentified bacteria. Sulfate-reducing bacteria were found in the column bioreactor 2 weeks after inoculation, but not thereafter. This suggests they were in low abundance, even though sulfate remediation rates were significant. Instead, the population contained species similar to those previously found to utilize humic substances released from the compost material.

Bacteria↗
PubMed2004

Biocatalytic asymmetric rearrangement of a methylene-interrupted bis-epoxide: simultaneous control of four asymmetric centers through a biomimetic reaction cascade.

Asymmetric enzyme-catalyzed hydrolysis of methylene-interrupted bis-epoxides 1 a and 1 b catalyzed by bacterial epoxide hydrolases furnished tetrahydrofuran derivatives 2 a and 2 b through a hydrolysis-rearrangement cascade. Whereas racemic bis-oxiranes 1 b-d underwent kinetic resolution with moderate stereoselectivities to yield products with up to 92 % ee and 66 % de: meso-bis-oxirane cis,cis-1 a was transformed into (6R,7R,9S,10S)-2 a in 94 % ee and 89 % de at high conversion (85 %) by Rhodococcus sp. CBS 717.73 as the major product. The reaction sequence resembles a biomimetic reaction cascade and provides an efficient entry into the structural core of annonaceous acetogenins with simultaneous control of four stereocenters.

Actinomycetales↗
PubMed1999

Isolation of a gene encoding a glycosylated cytokinin oxidase from maize.

The major cytokinin oxidase in immature maize kernels was purified to homogeneity. Selected tryptic peptides were used to design degenerate oligonucleotide primers for PCR isolation of a fragment of the oxidase gene. Hybridization of the PCR fragment to a maize genomic library allowed isolation of a full-length cytokinin oxidase gene (ckx1). The gene encodes a protein of approximately 57 kDa that possesses a signal peptide, eight consensus N-glycosylation sequences and a consensus FAD binding sequence. Expression of ckx1 in Pichia caused secretion of active glycosylated cytokinin oxidase that contains a substrate-reducible FAD. The gene displays sequence homology with a putative oxidoreductase from Arabidopsis thaliana and with the fas5 gene from Rhodococcus fascians.

Amino Acid Sequence↗
PubMed1999

Epoxide hydrolases and their synthetic applications.

Chiral epoxides and 1,2-diols, which are central building blocks for the asymmetric synthesis of bioactive compounds, can be obtained by using enzymes--i.e. epoxide hydrolases--which catalyse the enantioselective hydrolysis of epoxides. These biocatalysis have recently been found to be more widely distributed in fungi and bacteria than previously expected. Sufficient sources from bacteria, such as Rhodococcus and Nocardia spp., or fungi, as for instance Aspergillus and Beauveria spp., have now been identified. The reaction proceeds via an SN2-specific opening of the epoxide, leading to the formation of the corresponding trans-configured 1,2-diol. For the resolution of racemic monosubstituted and 2,2- or 2,3-disubstituted substrates, various fungi and bacteria have been shown to possess excellent enantioselectivities. Additionally, different methods, which lead to the formation of the optically pure product diol in a chemical yield far beyond the 50% mark (which is intrinsic to classic kinetic resolutions), are discussed. In addition, the use of non-natural nucleophiles such as azides or amines provides access to enantiomerically enriched vicinal azido- and amino-alcohols. The synthetic potential of these enzymes for asymmetric synthesis is illustrated with recent examples, describing the preparation of some biologically active molecules.

Epoxide Hydrolases↗