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Succinoyl trehalose lipid induced differentiation of human monocytoid leukemic cell line U937 into monocyte-macrophages.

A novel type of succinoyl trehalose lipid (STL-1) prepared from n-hexadecane-culture of Rhodococcus erythropolis SD-74 markedly inhibited the growth of a human monocytoid leukemic cell line, U937, and induced its morphological alteration along a monocyte-macrophage lineage. STL-1 markedly increased differention-associated characteristics in macrophage, such as nitroblue tetrazolium reducing ability, appearance of Fc receptor, phagocytic activities in U937. Furthermore, U937 cells, which were activated with STL-1 exhibited cytotoxic activity against human lung carcinoma cell line A549. However, STL-1 did not affect growth of a normal human fetal lung cell line TIG-1. The individual components of STL-1, neither sugar moiety nor fatty acids in the free form, were effective at inducing the differentiation of U937 cell. From these results, we concluded that STL-1 has low cytotoxicity against normal human cells and the ester molecule itself is responsible for the activity of inducing differentiation of human monocytoid leukemic cell line U937 into monocyte-macrophage which results in the stimulation of the production of some cytotoxic substances.

Biomarkers↗

PubMed1992

A colorimetric assay for measuring cell-free and cell-bound cholesterol oxidase.

Cholesterol oxidase (cholesterol:oxygen oxidoreductase, EC 1.1.3.6) catalyzes the conversion of sterol delta 5-3 beta-alcohol to the corresponding delta 4-3-ketone with the reduction of oxygen to hydrogen peroxide. Rhodococcus species GK 1, a soil isolated microbe, produces an extracellular and a membrane-bound cholesterol oxidase; the latter is bound to the outer surface of the microbial cell membrane. A simple and sensitive assay is described to measure the two enzyme types; no enzyme extraction is needed for measuring the membrane-bound cholesterol oxidase. In this assay, hydrogen peroxide is reduced by the chromogen 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in the presence of horseradish peroxidase, and the increased absorbance is followed continuously at 600 nm (epsilon m = 1.82 x 10(4) M-1.cm-1 at pH 7.0 and 30 degrees C). The standardized assay medium contained 46.9 mM sodium-potassium phosphate buffer pH 7.0, 0.16% Triton X-100, 312.5 microM ABTS, 50 micrograms peroxidase (12.5 units at 25 degrees C), 6.25% isopropanol, 306.3 microM cholesterol or other sterols (kept in solution with isopropanol), and cholesterol oxidase. Oxidation of one molecule of cholesterol by cholesterol oxidase gives one molecule of hydrogen peroxide which reacts with two molecules of ABTS. The method is reproducible and the results correlate well with those obtained by measuring the absorbance of delta 4-cholest-3-one at 240 nm (epsilon m = 1.40 x 10(4) M-1.cm-1 at pH 7.0 and 30 degrees C) and by the method of Allain et al. (Clin. Chem. 20, 470-475, 1974).(ABSTRACT TRUNCATED AT 250 WORDS)

1-Propanol↗

PubMed1998

Isolation and characterization of a bacterium possessing a novel aldoxime-dehydration activity and nitrile-degrading enzymes.

A bacterial strain capable of utilizing E-pyridine-3-aldoxime as a nitrogen source was isolated from soil after a 4-month acclimation period and was identified as Rhodococcus sp. The strain contained a novel aldoxime dehydration activity that catalyzed a stoichiometric dehydration of E-pyridine-3-aldoxime to form 3-cyanopyridine. The enzyme activity was induced by various aldoximes and nitriles. The strain metabolized the aldoxime as follows: E-pyridine-3-aldoxime was dehydrated to form 3-cyanopyridine, which was converted to nicotinamide by a nitrile hydratase, and the nicotinamide was successively hydrolyzed to nicotinic acid by an amidase.

Amidohydrolases↗

PubMed2002

Engineering an indene bioconversion process for the production of cis-aminoindanol: a model system for the production of chiral synthons.

Cis-aminoindanol, a key chiral precursor to the HIV protease inhibitor CRIXIVAN, can be derived from indene oxidation products of (2R) stereochemistry. A number of different microorganisms, notably strains of the genera Pseudomonas and Rhodococcus, have been isolated that catalyze the oxygenation of indene to indandiol with greater stereospecificity than is achievable through traditional chemical synthesis. The yield and ultimate optical purity of indandiol produced in such biocatalytic processes is influenced by the intrinsic stereospecificity of the oxygenase(s), enantioselective dehydrogenation, and the loss of substrate to alternate, undesirable metabolites. Metabolic engineering of any indene bioconversion system for the commercial-scale production of cis-aminoindanol must account for these influences, as well as pathway fluxes and enzyme regulation, to optimize the formation of oxygenated precursors with useful stereochemistry. As such, the process by which bacterial systems carry out the bioconversion of indene to indandiol serves as a model for biological production of industrially relevant chiral synthons.

Biotechnology↗

PubMed2004

Relation between bacterial strain resistance to solvents and biodesulfurization activity in organic medium.

Microorganisms used in biodesulfurization of petroleum products have to withstand high concentrations of hydrocarbons. The capacities of seven desulfurizing strains of Rhodococcus to be active in the presence of solvents were evaluated. Octanol and toluene (log P=2.9) were selected as toxic solvents. The effect of the solvents was determined by measuring either inhibition of growth or the decrease in respiratory activity of the cells. Differences among strains in their resistance to solvent responses were observed, but these variations were dependent on the test used. Resistance to solvents was then compared to the capacity of the different strains to retain biodesulfurization activity in the presence of hexadecane. Inhibition of desulfurization by high concentrations of hexadecane was found to be well correlated to the sensitivity of the strains to respiration inhibition by toluene, but not to growth inhibition. This result also showed that the respirometric test was a rapid and reliable test to select solvent-resistant strains for use as resting cells in biocatalysis processes, such as biodesulfurization, in organic media.

Alkanes↗

PubMed2004

Identification and functional analysis of the genes encoding dibenzothiophene-desulfurizing enzymes from thermophilic bacteria.

Thermophilic bacteria Bacillus subtilis WU-S2B and Mycobacterium phlei WU-F1 desulfurize dibenzothiophene (DBT) and alkylated DBTs through specific cleavage of the carbon-sulfur bonds over a temperature range up to 52 degrees C. In order to identify and functionally analyze the DBT-desulfurization genes, the gene cluster containing bdsA, bdsB, and bdsC was cloned from B. subtilis WU-S2B. The nucleotide and amino acid sequences of bdsABC show homologies to those of the other known DBT-desulfurization genes and enzymes; e.g. a nucleotide sequence homology of 61.0% to dszABC of the mesophilic bacterium Rhodococcus sp. IGTS8 and 57.8% to tdsABC of the thermophilic bacterium Paenibacillus sp. A11-2. Deletion and subcloning analysis of bdsABC revealed that the gene products of bdsC, bdsA and bdsB oxidized DBT to DBT sulfone (DBTO(2)), converted DBTO(2) to 2'-hydroxybiphenyl-2-sulfinate (HBPSi), and desulfurized HBPSi to 2-hydroxybiphenyl (2-HBP), respectively. Resting cells of a recombinant Escherichia coli JM109 harboring bdsABC converted DBT to 2-HBP over a temperature range of 30-52 degrees C, indicating that the gene products of bdsABC were functional in the recombinant. The activities of DBT degradation at 50 degrees C and DBT desulfurization (2-HBP production) at 40 degrees C in resting cells of the recombinant were approximately five times and twice, respectively, as high as those in B. subtilis WU-S2B. The recombinant E. coli cells also degraded alkylated DBTs, such as 2,8-dimethylDBT and 4,6-dimethylDBT. The nucleotide sequences of B. subtilis WU-S2B bdsABC and the corresponding genes from M. phlei WU-F1 were found to be completely identical to each other although the strains are genetically different.

Amino Acid Sequence↗

PubMed2005

Isolation of a bacterium that degrades urethane compounds and characterization of its urethane hydrolase.

A bacterium which degrades urethane compounds was isolated and identified as Rhodococcus equi strain TB-60. Strain TB-60 degraded toluene-2,4-dicarbamic acid dibutyl ester (TDCB) and accumulated toluene diamine as the degradation product. The enzyme which cleaves urethane bond in TDCB was strongly induced by acetanilide. The purified enzyme (urethane hydrolase) was found to be homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight was estimated to be 55 kDa. The optimal temperature and pH were 45 degrees C and 5.5, respectively. The enzyme hydrolyzed aliphatic urethane compound as well as aromatic ones. The activity was inhibited by HgCl(2), p-chrolomercuribenzoic acid, and phenylmethylsulfonyl fluoride, suggesting that cysteine and/or serine residues play an important role in the activity. The enzyme catalyzed the hydrolysis of anilides, amides, and esters as well as TDCB. It was characterized as a novel amidase/esterase, differing in some properties from other known amidases/esterases.

Amidohydrolases↗

PubMed2005

Continuous production of L(+)-tartaric acid from cis-epoxysuccinate using a membrane recycle reactor.

The one-step bioconversion of cis-epoxysuccinate (CES) to L(+)-tartaric acid by dried Rhodococcus rhodochrous cells containing CES hydrolase activity was studied by using a continuous bioconversion process. The influence of the pH and the temperature was assessed. A mathematical model was used to quantify the CES hydrolase activity and stability. The optimal pH, which resulted in a maximal CES hydrolase activity and stability, was pH 8.0. A large increase in stability (half-life time) could be obtained when the temperature was decreased from 37 to 14 degrees C during the continuous bioconversion. A total bioconversion was maintained for more than 100 days. This resulted in a large value for the specific productivity since the effect of the large increase in stability was much more important than the decrease of activity at the lower temperature. This continuous bioconversion process was further optimised by calculating the productivity for several continuously stirred tank reactors in series. The specific productivity could be nearly doubled when the number of reactors in the series was increased from 1 to 4.

Bioreactors↗

PubMed2006

Convenient treatment of acetonitrile-containing wastes using the tandem combination of nitrile hydratase and amidase-producing microorganisms.

This study aimed to construct an acetonitrile-containing waste treatment process by using nitrile-degrading microorganisms. To degrade high concentrations of acetonitrile, the microorganisms were newly acquired from soil and water samples. Although no nitrilase-producing microorganisms were found to be capable of degrading high concentrations of acetonitrile, the resting cells of Rhodococcus pyridinivorans S85-2 containing nitrile hydratase could degrade acetonitrile at concentrations as high as 6 M. In addition, an amidase-producing bacterium, Brevundimonas diminuta AM10-C-1, of which the resting cells degraded 6 M acetamide, was isolated. The combination of R. pyridinivorans S85-2 and B. diminuta AM10-C-1 was tested for the conversion of acetonitrile into acetic acid. The resting cells of B. diminuta AM10-C-1 were added after the first conversion involving R. pyridinivorans S85-2. Through this tandem process, 6 M acetonitrile was converted to acetic acid at a conversion rate of >90% in 10 h. This concise procedure will be suitable for practical use in the treatment of acetonitrile-containing wastes on-site.

Acetonitriles↗

PubMed2005

Cell adaptation to solvent, substrate and product: a successful strategy to overcome product inhibition in a bioconversion system.

Carvone has previously been found to highly inhibit its own production at concentrations above 50 mM during conversion of a diastereomeric mixture of (-)-carveol by whole cells of Rhodococcus erythropolis. Adaptation of the cells to the presence of increasing concentrations of carveol and carvone in n-dodecane prior to biotransformation proved successful in overcoming carvone inhibition. By adapting R. erythropolis cells for 197 h, an 8.3-fold increase in carvone production rate compared to non-adapted cells was achieved in an air-driven column reactor. After an incubation period of 268 h, a final carvone concentration of 1.03 M could be attained, together with high productivity [0.19 mg carvone h(-1) (ml organic phase)(-1)] and high yield (0.96 g carvone g carveol(-1)).

Adaptation, Physiological↗

PubMed1997

Biodegradation of methyl t-butyl ether by pure bacterial cultures.

Three pure bacterial cultures degrading methyl t-butyl ether (MTBE) were isolated from activated sludge and fruit of the Gingko tree. They have been classified as belonging to the genuses Methylobacterium, Rhodococcus, and Arthrobacter. These cultures degraded 60 ppm MTBE in 1-2 weeks of incubation at 23-25 degrees C. The growth of the isolates on MTBE as sole carbon source is very slow compared with growth on nutrient-rich medium. Uniformly-labeled [14C]MTBE was used to determine 14CO2 evolution. Within 7 days of incubation, about 8% of the initial radioactivity was evolved as 14CO2. These strains also grow on t-butanol, butyl formate, isopropanol, acetone and pyruvate as carbon sources. The presence of these compounds in combination with MTBE decreased the degradation of MTBE. The cultures pregrown on pyruvate resulted in a reduction in 14CO2 evolution from [14C]MTBE. The availability of pure cultures will allow the determination of the pathway intermediates and the rate-limiting steps in the degradation of MTBE.

Arthrobacter↗

PubMed1999

An extractive membrane biofilm reactor for degradation of 1,3-dichloropropene in industrial waste water.

A bacterial biofilm, capable of mineralising a technical mixture of cis- and trans-1,3-dichloropropene (DCPE), was enriched on the biomedium side of an extractive membrane biofilm reactor (EMBR). The membrane separates the biomedium from the industrial waste water, in terms of pH, ionic strength and the concentration of toxic chemicals. The biofilm, attached to a silicone membrane, is able to mineralize DCPE after its diffusion through the membrane. Five bacterial strains with degradation capabilities were isolated from the metabolically active biofilm and further investigated in batch experiments. Two of them, Rhodococcus erythropolis strains EK2 and EK5, can grow with DCPE as the sole carbon source. Pseudomonas sp. EK1 uzilizes cis-3-chloroallylalcohol and cis-3-chloroacrylic acid, whereas the metabolite trans-3-chloroacrylic acid represents a dead-end product of the pathway of this strain. The other two strains, Delftia sp. EK3 and EK4, although unable to grow with DCPE as the carbon source, can transform DCPE and its upper-pathway intermediates at reasonable conversion rates. They may represent helper functions of the biofilm consortium, which mineralised up to 12.5 mmol DCPE per hour per gram of biomass protein. Higher feed rates in the EMBR (up to 15 mmol per hour per 100-l bioreactor volume) and shock loads corresponding to concentrations up to 1.8 mmol l-1 led to a significant increase in the freely floating bacterial biomass in the reactor medium (OD546 = 0.2). At the standard operating feed rate of 1.8 mmol h-1, the free biomass concentration was very low (OD546 = 0.04).

Allyl Compounds↗

PubMed2001

Transformation of 2,2'-dichlorodiisopropyl ether in mixed and pure culture.

An aerobic enrichment culture derived from a groundwater contaminated with organic and chloroorganic compounds was adapted to the transformation of 2,2'-dichlorodiisopropyl ether (DDE) in a continuous fixed-bed bioreactor. Continuous DDE removal efficiencies over 90% were achieved with a model water containing 3.3 mM methanol as co-substrate at DDE loading rates of up to 150 micromol l(-1) day(-1) with a hydraulic retention time of 24 h. In batch cultures, a stoichiometric release of 2 micromol chloride per micromol DDE transformed was observed. From the mixed culture, a strain was isolated that is able to grow on DDE as the sole energy and carbon source, tolerating DDE concentrations of up to 1 mM. Based on 16S rRNA sequencing, the strain is affiliated with the genus Rhodococcus.

Aerobiosis↗

PubMed2001

Desulfurization and desulfonation: applications of sulfur-controlled gene expression in bacteria.

Inorganic sulfate is the preferred sulfur source for the growth of most microorganisms but, in its absence, many organosulfur compounds can be degraded microbially to provide sulfur. Desulfurization of dibenzothiophene (DBT) by Rhodococcus sp. and of aromatic sulfonates by Pseudomonas sp. has considerable biotechnological potential. Both these pathways require non-flavin-containing FMNH2-dependent monoxygenases (DszC/DszA and SsuD, respectively). FMNH2 is provided from the freely diffusible FMNH2 pool in the cell, and is replenished by specific NAD(P)H:FMN oxidoreductases (DszD and SsuE). Overexpression of the DszD FMN reductase in a heterologous system increases the efficiency of DBT desulfurization but is detrimental to cell growth at high levels. Expression of the sulfonatase that cleaves aromatic sulfonates (surfactants, dyes) is accompanied by synthesis of a thiol-specific antioxidant protein, which may protect the cell from superoxide radicals generated by autoxidation of the reduced flavin. Effective application of DBT desulfurization in the biodesulfurization of crude oil, and of arylsulfonate desulfonation in bioremediation, may require optimization of both flavin reductase levels and antioxidant protection systems within the cell.

Agriculture↗

PubMed2004

Enantioselective hydrolysis of butyl 2-ethylhexanoate by a strain of Nocardia corynebacteroides.

The results of a screen for microbial esterases that have enantioselective activity for the hydrolysis of butyl 2-ethylhexanoate are described. The preliminary screen determined that a nocardioform bacterial strain, NRRL 21057, exhibited significant activity in preferentially hydrolyzing the S enantiomer of butyl 2-ethylhexanoate. Molecular systematics methods identified NRRL 21057 as a strain of Nocardia corynebacteroides. A survey of phylogenetically related species in the genera Gordonia, Rhodococcus, and Nocardia strains demonstrated that N. corynebacteroides NRRL 21057 is the most active strain known for the specific hydrolysis of the R-isomer of butyl 2-ethylhexanoate and that it provides the S-isomer of 2-ethylhexanoate in 86% enantiomeric excess within 22 h.

Caproates↗

PubMed2004

Polymorphisms in equine immune response genes and their associations with infections.

Polymorphic markers identified in the horse genes encoding the interleukin 12 p40 subunit, interferon gamma, tumor necrosis factor receptor 1, and inducible nitric oxide synthase were identified and tested, along with additional markers, for associations with two important horse infections: Rhodococcus equi and Lawsonia intracellularis. Eight immune response-related and 14 microsatellite loci covering 12 out of 31 equine autosomes were used for the association analysis. Markers located on horse Chromosomes Eca10 and 15 were significantly associated with the presence of high numbers of R. equi in transtracheal aspirates. Significant associations of markers located on Eca9, 15, and 21 with fecal shedding of Lawsonia intracellularis were found. Marginal associations with tumor necrosis factor alpha, interferon gamma, and other genes suggested that variations in immune response-related genes could underlie the phenotypic variation observed.

Animals↗

PubMed2003

Culture collections and biochemistry.

This review describes the relationships and links between culture collections, which act as sources of genomes, transcriptomes, proteome, and metabolomes, and fields of research biochemistry that demand their support and help. In addition, the invaluable but not always rewarded efforts of these organizations as a source and conservator of organism diversity is discussed. Biological waste-water treatment, ethanol as a non-finite source of energy, Rhodococcus fascians as the source of a citrus-juice debittering agent, the sporulation of filamentous fungi in liquid medium, and biotransformation with growing and resting cells are processes developed by the authors that demonstrate some of the applications of organisms from culture collections in the general field of biotechnology and related areas, including industrial biochemistry and biocatalytic synthesis.

Biochemical Phenomena↗

PubMed2003

Biotransformation of beta-ketosulfides to produce chiral beta-hydroxysulfoxides.

The biotransformations of a series of substituted phenylthio-2-propanone and benzylthio-2-propanone were carried out using Helminthosporium sp. NRRL 4671, Mortierella isabellina ATCC 42613, or Rhodococcus erythropolis IGTS8. Several products gave microbial oxidation of sulfide to sulfoxide and reduction of carbonyl to secondary alcohol, producing beta-hydroxysulfoxides in medium to high enantiomeric and diastereomeric purities. Fungal biotransformations using Helminthosporium sp. and M. isabellina resulted in the opposite sulfoxide configurations of various beta-hydroxysulfoxide products.

Biotransformation↗