Relevant bibliographies by topics / Bacteria; Rhodococcus rhodochrous; Enzymes

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  1. Journal articles
  2. Dissertations / Theses
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Academic literature on the topic 'Bacteria; Rhodococcus rhodochrous; Enzymes'

Author: Grafiati
Published: 4 June 2021
Last updated: 6 February 2022

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Journal articles on the topic "Bacteria; Rhodococcus rhodochrous; Enzymes"

1

Clark, Daniel D., and Scott A. Ensign. "Evidence for an Inducible Nucleotide-Dependent Acetone Carboxylase in Rhodococcus rhodochrousB276." Journal of Bacteriology 181, no. 9 (May 1, 1999): 2752–58. http://dx.doi.org/10.1128/jb.181.9.2752-2758.1999.

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ABSTRACT The metabolism of acetone was investigated in the actinomyceteRhodococcus rhodochrous (formerly Nocardia corallina) B276. Suspensions of acetone- and isopropanol-grownR. rhodochrous readily metabolized acetone. In contrast,R. rhodochrous cells cultured with glucose as the carbon source lacked the ability to metabolize acetone at the onset of the assay but gained the ability to do so in a time-dependent fashion. Chloramphenicol and rifampin prevented the time-dependent increase in this activity. Acetone metabolism by R. rhodochrous was CO2 dependent, and 14CO2 fixation occurred concomitant with this process. A nucleotide-dependent acetone carboxylase was partially purified from cell extracts of acetone-grownR. rhodochrous by DEAE-Sepharose chromatography. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggested that the acetone carboxylase was composed of three subunits with apparent molecular masses of 85, 74, and 16 kDa. Acetone metabolism by the partially purified enzyme was dependent on the presence of a divalent metal and a nucleoside triphosphate. GTP and ITP supported the highest rates of acetone carboxylation, while CTP, UTP, and XTP supported carboxylation at 10 to 50% of these rates. ATP did not support acetone carboxylation. Acetoacetate was determined to be the stoichiometric product of acetone carboxylation. The longer-chain ketones butanone, 2-pentanone, 3-pentanone, and 2-hexanone were substrates. This work has identified an acetone carboxylase with a novel nucleotide usage and broader substrate specificity compared to other such enzymes studied to date. These results strengthen the proposal that carboxylation is a common strategy used for acetone catabolism in aerobic acetone-oxidizing bacteria.
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2

Krum, Jonathan G., and Scott A. Ensign. "Heterologous Expression of Bacterial Epoxyalkane:Coenzyme M Transferase and Inducible Coenzyme M Biosynthesis in Xanthobacter Strain Py2 andRhodococcus rhodochrous B276." Journal of Bacteriology 182, no. 9 (May 1, 2000): 2629–34. http://dx.doi.org/10.1128/jb.182.9.2629-2634.2000.

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ABSTRACT Coenzyme M (CoM) (2-mercaptoethanesulfonic acid) biosynthesis is shown to be coordinately regulated with the expression of the enzymes of alkene and epoxide metabolism in the propylene-oxidizing bacteriaXanthobacter strain Py2 and Rhodococcus rhodochrous strain B276. These results provide the first evidence for the involvement of CoM in propylene metabolism by R. rhodochrous and demonstrate for the first time the inducible nature of eubacterial CoM biosynthesis.
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STRACHAN, Philip D., Andrew A. FREER, and Charles A. FEWSON. "Purification and characterization of catechol 1,2-dioxygenase from Rhodococcus rhodochrous NCIMB 13259 and cloning and sequencing of its catA gene." Biochemical Journal 333, no. 3 (August 1, 1998): 741–47. http://dx.doi.org/10.1042/bj3330741.

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A method was developed for the purification of catechol 1,2-dioxygenase from Rhodococcus rhodochrous NCIMB 13259 that had been grown in the presence of benzyl alcohol. The enzyme has very similar apparent Km (1–2 µM) and Vmax (13–19 units/mg of protein) values for the intradiol cleavage of catechol, 3-methylcatechol and 4-methylcatechol and it is optimally active at pH 9. Cross-linking studies indicate that the enzyme is a homodimer. It contains 0.6 atoms of Fe per subunit. The enzyme was crystallized with 15% (w/v) poly(ethylene glycol) 4000/0.33 M CaCl2/25 mM Tris (pH 7.5) by using a microseeding technique. Preliminary X-ray characterization showed that the crystals are in space group C2 with unit-cell dimensions a = 111.9 Å, b = 78.1 Å, c = 134.6 Å, β = 100 °. An oligonucleotide probe, made by hemi-nested PCR, was used to clone the gene encoding catechol 1,2-dioxygenase (catA). The deduced 282-residue sequence corresponds to a protein of molecular mass 31539 Da, close to the molecular mass of 31558 Da obtained by electrospray MS of the purified enzyme. catA was subcloned into the expression vector pTB361, allowing the production of catechol 1,2-dioxygenase to approx. 40% of the total cellular protein. The deduced amino acid sequence of the enzyme has 56% and 75% identity with the catechol 1,2-dioxygenases of Arthrobacter mA3 and Rhodococcus erythropolis AN-13 respectively, but less than 35% identity with intradiol catechol and chlorocatechol dioxygenases of Gram-negative bacteria. The nucleotide sequence data reported will appear in DDBJ, EMBL and GenBank Nucleotide Sequence Databases under the accession number AF043741.
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4

Poelarends, Gerrit J., Leonid A. Kulakov, Michael J. Larkin, Johan E. T. van Hylckama Vlieg, and Dick B. Janssen. "Roles of Horizontal Gene Transfer and Gene Integration in Evolution of 1,3-Dichloropropene- and 1,2-Dibromoethane-Degradative Pathways." Journal of Bacteriology 182, no. 8 (April 15, 2000): 2191–99. http://dx.doi.org/10.1128/jb.182.8.2191-2199.2000.

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ABSTRACT 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 indhaR led to constitutive expression of dhaA in strain GP1, in contrast to the inducible expression of dhaAin 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 conserveddhaA 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.
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5

Boyd, Jeffrey M., Ashley Ellsworth, and Scott A. Ensign. "Characterization of 2-Bromoethanesulfonate as a Selective Inhibitor of the Coenzyme M-Dependent Pathway and Enzymes of Bacterial Aliphatic Epoxide Metabolism." Journal of Bacteriology 188, no. 23 (September 22, 2006): 8062–69. http://dx.doi.org/10.1128/jb.00947-06.

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ABSTRACT Bacterial growth with short-chain aliphatic alkenes requires coenzyme M (CoM) (2-mercaptoethanesulfonic acid), which serves as the nucleophile for activation and conversion of epoxide products formed from alkene oxidation to central metabolites. In the present work the CoM analog 2-bromoethanesulfonate (BES) was shown to be a specific inhibitor of propylene-dependent growth of and epoxypropane metabolism by Xanthobacter autotrophicus strain Py2. BES (at low [millimolar] concentrations) completely prevented growth with propylene but had no effect on growth with acetone or n-propanol. Propylene consumption by cells was largely unaffected by the presence of BES, but epoxypropane accumulated in the medium in a time-dependent fashion with BES present. The addition of BES to cells resulted in time-dependent loss of epoxypropane degradation activity that was restored upon removal of BES and addition of CoM. Exposure of cells to BES resulted in a loss of epoxypropane-dependent CO2 fixation activity that was restored only upon synthesis of new protein. Addition of BES to cell extracts resulted in an irreversible loss of epoxide carboxylase activity that was restored by addition of purified 2-ketopropyl-CoM carboxylase/oxidoreductase (2-KPCC), the terminal enzyme of epoxide carboxylation, but not by addition of epoxyalkane:CoM transferase or 2-hydroxypropyl-CoM dehydrogenase, the enzymes which catalyze the first two reactions of epoxide carboxylation. Comparative studies of the propylene-oxidizing actinomycete Rhodococcus rhodochrous strain B276 showed that BES is an inhibitor of propylene-dependent growth in this organism as well but is not an inhibitor of CoM-independent growth with propane. These results suggest that BES inhibits propylene-dependent growth and epoxide metabolism via irreversible inactivation of the key CO2-fixing enzyme 2-KPCC.
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6

Toraya, Tetsuo, Takayuki Oka, Manabu Ando, Mamoru Yamanishi, and Hiroshi Nishihara. "Novel Pathway for Utilization of Cyclopropanecarboxylate by Rhodococcus rhodochrous." Applied and Environmental Microbiology 70, no. 1 (January 2004): 224–28. http://dx.doi.org/10.1128/aem.70.1.224-228.2004.

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ABSTRACT A new strain isolated from soil utilizes cyclopropanecarboxylate as the sole source of carbon and energy and was identified as Rhodococcus rhodochrous (H. Nishihara, Y. Ochi, H. Nakano, M. Ando, and T. Toraya, J. Ferment. Bioeng. 80:400-402, 1995). A novel pathway for the utilization of cyclopropanecarboxylate, a highly strained compound, by this bacterium was investigated. Cyclopropanecarboxylate-dependent reduction of NAD+ in cell extracts of cyclopropanecarboxylate-grown cells was observed. When intermediates accumulated in vitro in the absence of NAD+ were trapped as hydroxamic acids by reaction with hydroxylamine, cyclopropanecarboxohydroxamic acid and 3-hydroxybutyrohydroxamic acid were formed. Cyclopropanecarboxyl-coenzyme A (CoA), 3-hydroxybutyryl-CoA, and crotonyl-CoA were oxidized with NAD+ in cell extracts, whereas methacrylyl-CoA and 3-hydroxyisobutyryl-CoA were not. When both CoA and ATP were added, organic acids corresponding to the former three CoA thioesters were also oxidized in vitro by NAD+, while methacrylate, 3-hydroxyisobutyrate, and 2-hydroxybutyrate were not. Therefore, it was concluded that cyclopropanecarboxylate undergoes oxidative degradation through cyclopropanecarboxyl-CoA and 3-hydroxybutyryl-CoA. The enzymes catalyzing formation and ring opening of cyclopropanecarboxyl-CoA were shown to be inducible, while other enzymes involved in the degradation were constitutive.
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Cincilei, Angela G., Svetlana A. Tolocichina, Inna O. Rastimesina, Ion P. Dragalin, Veronica Dumbraveanu, Nina V. Streapan, and Vera C. Mamaliga. "Preparation of Microbiological Agents for Organic Pollutants Removal in Wastewater." Chemistry Journal of Moldova 4, no. 2 (December 2009): 40–43. http://dx.doi.org/10.19261/cjm.2009.04(2).13.

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The authors have investigated the biochemical aspects of degradation processes of persistent organic compound benzothiazole by immobilized Rhodococcus rhodochrous cells, such as entrapped in Ca-alginate beads, or as being immobilized on some solid carries. The mineralization of toxicant was complete and biodestructive capacity of entrapped in alginate bacteria increased with each new experimental cycle.
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Arriaga, José Miguel, Noah D. Cohen, James N. Derr, M. Keith Chaffin, and Ronald J. Martens. "Detection of Rhodococcus Equi by Polymerase Chain Reaction Using Species-Specific Nonproprietary Primers." Journal of Veterinary Diagnostic Investigation 14, no. 4 (July 2002): 347–53. http://dx.doi.org/10.1177/104063870201400416.

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Species-specific primers for the polymerase chain reaction (PCR) for the detection of Rhodococcus equi were developed. These primers were based on unique DNA fragments produced from R. equi reference strains and field isolates. Following random amplification of polymorphic DNA from R. equi and R. rhodochrous with a set of 40 arbitrary 10–base pair (bp) primers, a pair of species-specific primers was designed to detect a unique 700-bp fragment of R. equi chromosomal DNA. This PCR product was limited to R. equi and was not detectable in other Rhodococcus species or in a panel of additional gram-positive and gram-negative bacteria.
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9

Obidi, O. F. "Comparative Fatty Acid Profiling of Klebsiella pneumoniae and Rhodococcus rhodochrous Isolated from Spoilt Paints by Gas Chromatography." Nigerian Journal of Biotechnology 37, no. 2 (March 12, 2021): 47–55. http://dx.doi.org/10.4314/njb.v37i2.5.

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The use of fatty acids to study the differences in un-related microbes is limited. This study analyzes the fatty acids produced by two unrelated microorganisms: Klebsiella pneumoniae (Gram-negative, aerobic, non-endospore forming, usually encapsulated rod-shaped bacteria of the family Enterobacteriaceae) and Rhodococcus rhodochrous (metabolically versatile, non-spore-forming, non-motile actinomycete) isolated from spoilt paints. Fatty acids produced by the organisms were analyzed using an efficient MIDI-Sherlock gas chromatography method . K. pneumoniae was characterized by a high content of straight chain, branched chain, hydroxyl and cyclo-fatty acids made up of C12: 0, C13:0, C14:0 iso, C14:0, C15:0 iso, C15:0 anteiso, C15:1 ω 8c, C15:0, C16:0 iso, C16:1w5c, C16:0, C15:03OH, C17:1 ω 8c, C17:0 cyclo, C17:0, C18:1 ω5c and C18:0. R. rhodochrous was dominated by straight chain, monounsaturated and 10-methyl fatty acids. The inability to synthesize branched, cyclo- and hydroxyl- fatty acids, was observed in R. rhodochrous which composed mainly of C14: 0, C15: 1 ω 5c, C15:0, C16:1 ω 9c, C16:0, C17:1 ω 8c, C17:0, C17:0 10-methyl, C18: 1 ω 9c, C18.0, 10 methyl-C18:0 TBSA, C20:1 ω 9c, and C20:0. Descriptive statistics reveal a mean of 2.53, 15.10 and 15.15 for retention time (RT), equivalent chain length (ECL) and Peak name, respectively. Possible implications of the variations in fatty acid distribution may include differences in their abilities to produce various secondary metabolites and potentials to degrade a variety of xenobiotics. Keywords: Fatty acids, paints, Rhodococcus rhodochrous, Klebsiella pneumoniae
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Tauber, M. M., A. Cavaco-Paulo, K. H. Robra, and G. M. Gübitz. "Nitrile Hydratase and Amidase fromRhodococcus rhodochrous Hydrolyze Acrylic Fibers and Granular Polyacrylonitriles." Applied and Environmental Microbiology 66, no. 4 (April 1, 2000): 1634–38. http://dx.doi.org/10.1128/aem.66.4.1634-1638.2000.

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ABSTRACT Rhodococcus rhodochrous NCIMB 11216 produced nitrile hydratase (320 nkat mg of protein−1) and amidase activity (38.4 nkat mg of protein−1) when grown on a medium containing propionitrile. These enzymes were able to hydrolyze nitrile groups of both granular polyacrylonitriles (PAN) and acrylic fibers. Nitrile groups of PAN40 (molecular mass, 40 kDa) and PAN190 (molecular mass, 190 kDa) were converted into the corresponding carbonic acids to 1.8 and 1.0%, respectively. In contrast, surfacial nitrile groups of acrylic fibers were only converted to the corresponding amides. X-ray photoelectron spectroscopy analysis showed that 16% of the surfacial nitrile groups were hydrolyzed by the R. rhodochrousenzymes. Due to the enzymatic modification, the acrylic fibers became more hydrophilic and thus, adsorption of dyes was enhanced. This was indicated by a 15% increase in the staining level (K/Svalue) for C.I. Basic Blue 9.
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More sources

Dissertations / Theses on the topic "Bacteria; Rhodococcus rhodochrous; Enzymes"

1

Dadd, Michael Richard. "Chiral biotransformations of cylclic nitrile compounds." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365818.

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Thuku, Robert Ndoria. "The structure of the nitrilase from Rhodococcus Rhodochrous J1: homology modeling and three-dimensional reconstruction." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_3225_1188474860.

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The nitrilases are an important class of industrial enzymes that are found in all phyla. These enzymes are expressed widely in prokaryotes and eukaryotes. Nitrilases convert nitriles to corresponding acids and ammonia. They are used in industry as biocatalysts because of their specificity and enantioselectivity. These enzymes belong to the nitrilase superfamily in which members share a common &alpha
&beta
&beta
&alpha
structural fold and a unique cys, glu,lys catalytic triad with divergent N- and C-terminals.

There are four atomic structures of distant homologues in the superfamily, namely 1ems, 1erz, 1f89 and 1j31. All structures have two-fold symmetry which conserves the &alpha
&beta
&beta
&alpha
-&alpha
&beta
&beta
&alpha
fold across the dimer interface known as the A surface. The construction of a 3D model based on the solved structures revealed the enzyme has two significant insertions in its sequence relative to the solved structures, which possibly correspond to the C surface. In addition there are intermolecular interactions in a region of a conserved helix, called the D surface. These surfaces contribute additional interactions responsible for spiral formation and are absent in the atomic resolution homologues.

The recombinant enzyme from R.rhodochrous J1 was expressed in E. coli BL21 cells and eluted by gel filtration chromatography as an active 480 kDa oligomer and an inactive 80 kDa dimer in the absence of benzonitrile. This contradicts previous observations, which reported the native enzyme exists as an inactive dimer and elutes as a decamer in the presence benzonitrile. Reducing SDS-PAGE showed a subunit atomic mass of ~40 kDa. EM and image analysis revealed single particles of various shapes and sizes, including c-shaped particles, which could not form spirals due to steric hindrances in its C terminal.

Chromatographic re-elution of an active fraction of 1-month old J1 nitrilase enabled us to identify an active form with a mass greater than 1.5 MDa. Reducing SDS-PAGE, N-terminal sequencing and mass spectroscopy showed the molecular weight was ~36.5 kDa as result of specific proteolysis in its C terminal. EM revealed the enzyme forms regular long fibres. Micrographs (109) were recorded on film using a JEOL 1200EXII operating at 120 kV at 50K magnification. Two independent 3D reconstructions were generated using the IHRSR algorithm executed in SPIDER. These converged to the same structure and the resolution using the FSC 0.5 criterion was 1.7 nm.

The helix structure has a diameter of 13nm with ~5 dimers per turn in a pitch of 77.23 Å
. Homology modeling and subsequent fitting into the EM map has revealed the helix is built primarily from dimers, which interact via the C and D surfaces. The residues, which potentially interact across the D surface, have been identified and these confer stability to the helix. The conservation of the insertions and the possibility of salt bridge formation on the D surface suggest that spiral formation is common among microbial nitrilases. Furthermore, the presence of the C terminal domain in J1 nitrilase creates a steric hindrance that prevents spiral formation. When this is lost &ndash
either by specific proteolysis or autolysis - an active helix is formed.

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Frederick, Joni. "Genetic characterization of Rhodococcus rhodochrous ATCC BAA-870 with emphasis on nitrile hydrolysing enzymes." Doctoral thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/4262.

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Includes abstract.
Includes bibliographical references.
Rhodococcus rhodochrous ATCC BAA-870 (BAA-870) had previously been isolated on selective media for enrichment of nitrile hydrolysing bacteria. The organism was found to have a wide substrate range, with activity against aliphatics, aromatics, and aryl aliphatics, and enantioselectivity towards beta substituted nitriles and beta amino nitriles, compounds that have potential applications in the pharmaceutical industry. This makes R. rhodochrous ATCC BAA-870 potentially a versatile biocatalyst for the synthesis of a broad range of compounds with amide and carboxylic acid groups that can be derived from structurally related nitrile precursors. The selectivity of biocatalysts allows for high product yields and better atom economy than nonselective chemical methods of performing this reaction, such as acid or base hydrolysis. In order to apply BAA-870 as a nitrile biocatalyst and to mine the organism for biotechnological uses, the genome was sequenced using Solexa technology and an Illumina Genome Analyzer. The Solexa sequencing output data was analysed using the Solexa Data Analysis Pipeline and a total of 5,643,967 reads, 36-bp in length, were obtained providing 4,273,289 unique sequences. The genome sequence data was assembled using the software Edena, Velvet, and Staden. The best assembly data set was then annotated automatically using dCAS and BASys. Further matepaired sequencing, contracted to the company BaseClear® BV in Leiden, the Netherlands, was performed in order to improve the completeness of the data. The scaffolded Illumina and mate-paired sequences were further assembled and annotated using BASys. BAA-870 has a GC content of 65% and contains 6997 predicted protein-coding sequences (CDS). Of this, 54% encodes previously identified proteins of unknown function. The completed 5.83 Mb genome (with a sequencing coverage of 135 X) was submitted to the NCBI Genome data bank with accession number PRJNA78009. The genome sequence of R. rhodochrous ATCC BAA-870 is the seventh rhodococcal genome to be submitted to the NCBI and the first R. rhodochrous subtype to be sequenced. An analysis of the genome for nitrile
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WANG, CUI. "Enhanced Activity And Stability Of Enzymes Associated With Delayed Fruit Ripening In Rhodococcus rhodochrous DAP 96253." Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/biology_diss/131.

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Rhodococcus has diverse metabolic capabilities, such as delaying ripening of certain climacteric fruit. Nitrile hydratase (NHase), amidase, 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase), cyanidase, and β-cyanoalanine synthase-like enzyme (βCAS-like) are possibly involved in fruit ripening. The activity of these enzymes in Rhodococcus rhodochrous DAP 96253 cells were induced with selected multiple inducers (i.e. cobalt and urea). This research showed that the supplementation of selected sugars, i.e. trehalose and maltodextrin in growth media and storage buffers of R. rhodochrous DAP 96253 affected activity and stability of the enzymes mentioned above. Thermostability and osmostability of the five enzymes in whole cells (plate grown and fermented) were evaluated in this study, i.e. βCAS-like was more stable than the other four enzymes in storage conditions. Immobilized biocatalysts have practical advantages over the use of “free” whole cells. Immobilization of whole rhodococcal cells (plate grown and fermented) was employed, using techniques such as glutaraldehyde-polyethylenimine (GA-PEI) cross-linking, waxing and calcium-alginate entrapment. The GA-PEI immobilized catalysts were non-replicating and more stable in storage conditions than the catalysts produced by the other two methods. Wax or calcium-alginate immobilized catalysts (live catalysts) showed higher enzyme activity than the GA-PEI catalyst. The effects of whole and immobilized catalysts were evaluated on delayed ripening of fruit. Both free whole cells and immobilized catalysts delayed the ripening of bananas and peaches. Delayed ripening experiments showed that the catalysts were effective in direct contact and not in contact with fruit. Moreover, both free whole cells and immobilized catalysts showed antifungal activity against Aspergillus niger and Penicillium spp. Gas chromatography was performed to analyze volatile interactions between the biocatalysts and fruit. This analysis revealed that cyanide in an atmosphere with ethylene was utilized by the biocatalysts. There was also less volatile production by exposed fruit (bananas) than fruit unexposed to biocatalysts, either rhodococcal immobilized catalysts or live whole cells (plate grown and fermented).
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Perry, Guenevere Diane. "Enhancing the Expression of Enzymes Used to Degrade Hydrocarbons and Cyanohydrins in Rhodococcus sp. DAP 96253 by Using Inducers such as Cobalt, Urea, and Propylene Gas; Also Enhances the Ability of the Bacteria to Delay the Ripening of Several Fruit Species." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/biology_diss/102.

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ABSTRACT Recent studies have shown that R. rhodochrous DAP 96253 has the ability to delay the ripening of many climacteric fruit, by potentially degrading volatile compounds released by plant cells during the ripening process. Rhodococcus rhodochrous DAP 96253 cells were cultured on YEMEA medium supplemented with inducers, (16mM cobalt and 125mM urea), that over-expressed nitrile hydratase (NHase) and amidase (AMDase) enzymes. Cells were cultured on propylene/ ethylene as sole carbon source to induce alkene monooxygenase (AMO) like activity. Induced R. rhodochrous DAP 96253 cells displayed an 83% increase in final total dry weight compared to cells previously cultured on non-induced medium. Induced R. rhodochrous DAP 96253 cells displayed a 53-85% increase in NHase activity after exposure to propylene/ethylene, and cells displayed a 24-53% increase in NHase activity after exposure to fruit. Non-induced R. rhodochrous DAP 96253 cells displayed a 1-5% increase in NHase activity after propylene/ethylene, and cells displayed an 18-38% increase in NHase activity after exposure to fruit. Propylene/ethylene induced nitrilase activity in non-induced R. rhodochrous DAP 96253cells. Experimental results suggest that R. rhodochrous DAP 96253 may use NHase, amidase, nitrilase, and AMO like activity to delay ripening of climacteric fruit. Rhodococcus rhodochrous 96253 cells cultured on propylene/ethylene and cofactors (16mM cobalt and 125mM urea) displayed improved ability to delay ripening of fruit.
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6

Mashweu, Adelaide. "Substrate evaluation of the nitrile degrading enzymes from Rhodococcus rhodochrous ATCC BAA 870." Thesis, 2020. https://hdl.handle.net/10539/31394.

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A dissertation submitted to the Faculty of Science, University of the Witwatersrand in fulfilment for the requirements of the degree of Master of Science, 2020
The focus of this research was the nitrile degrading enzymes nitrile hydratases (NHase) and whole cell nitrilases. NHases and whole cell nitrilases have not been as extensively applied in industry as they could be due to a number of reasons, including missing information relating to their substrate scope. Therefore, this research focussed on exploring the activity of both NHase and whole cell nitrilase towards a number of nitrile compounds. The Groebke-Blackburn-Bienayméreaction (GBB) and Suzuki-Miyaura coupling reaction were employed to synthesize aromatic nitrile-bearing imidazo[1,2-a]pyridine and biaryl compounds respectively. These compounds were of varying sizes and the nitrile group was subjected to different electronic effects through incorporation of different substituents. Vinyl nitrile compounds were synthesized using the Morita-Baylis Hillman reaction (MBH), while simple nitrile compounds were purchased. The synthesized nitrile-bearing imidazo[1,2-a]pyridine compounds were subjected to both NHase and whole cell nitrilase, however, these enzymes were inactive towards these compounds. NHase showed activity towards the biaryl compounds, however, there was complete loss of activity when the biaryl compounds had a 3,4-dimethoxy group as a substituent irrespective of its position relative to the nitrile group. There was also no activity when the 3,4-difluorophenyl group was in the ortho-position relative to the nitrile functional group. NHase also showed activity towards the MBH compounds, however, the rate of hydrolysis was slow in comparison with that of the biaryl compounds. NHase was inactive towards one MBH compound bearing a trimethoxyphenylgroup as a substituent. Whole cell Nitrilase had no activity towards the MBH compounds and extending the time for hydrolysis resulted in no significant changes. NHase demonstrated excellent activity towards the simple commercially available nitrile compounds, however, the rate of hydrolysis towards nitrile compounds bearing electron-withdrawing substituents was faster in comparison with those bearing electron-donating substituents
CK2021
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7

Wang, Cui. "Enhanced Activity And Stability Of Enzymes Associated With Delayed Fruit Ripening In Rhodococcus rhodochrous DAP 96253." 2013. http://scholarworks.gsu.edu/biology_diss/131.

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Rhodococcus has diverse metabolic capabilities, such as delaying ripening of certain climacteric fruit. Nitrile hydratase (NHase), amidase, 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase), cyanidase, and β-cyanoalanine synthase-like enzyme (βCAS-like) are possibly involved in fruit ripening. The activity of these enzymes in Rhodococcus rhodochrous DAP 96253 cells were induced with selected multiple inducers (i.e. cobalt and urea). This research showed that the supplementation of selected sugars, i.e. trehalose and maltodextrin in growth media and storage buffers of R. rhodochrous DAP 96253 affected activity and stability of the enzymes mentioned above. Thermostability and osmostability of the five enzymes in whole cells (plate grown and fermented) were evaluated in this study, i.e. βCAS-like was more stable than the other four enzymes in storage conditions. Immobilized biocatalysts have practical advantages over the use of “free” whole cells. Immobilization of whole rhodococcal cells (plate grown and fermented) was employed, using techniques such as glutaraldehyde-polyethylenimine (GA-PEI) cross-linking, waxing and calcium-alginate entrapment. The GA-PEI immobilized catalysts were non-replicating and more stable in storage conditions than the catalysts produced by the other two methods. Wax or calcium-alginate immobilized catalysts (live catalysts) showed higher enzyme activity than the GA-PEI catalyst. The effects of whole and immobilized catalysts were evaluated on delayed ripening of fruit. Both free whole cells and immobilized catalysts delayed the ripening of bananas and peaches. Delayed ripening experiments showed that the catalysts were effective in direct contact and not in contact with fruit. Moreover, both free whole cells and immobilized catalysts showed antifungal activity against Aspergillus niger and Penicillium spp. Gas chromatography was performed to analyze volatile interactions between the biocatalysts and fruit. This analysis revealed that cyanide in an atmosphere with ethylene was utilized by the biocatalysts. There was also less volatile production by exposed fruit (bananas) than fruit unexposed to biocatalysts, either rhodococcal immobilized catalysts or live whole cells (plate grown and fermented).
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Reports on the topic "Bacteria; Rhodococcus rhodochrous; Enzymes"

1

Ho, N. W. Y. Characterization of the organic-sulfur-degrading enzymes. [IGTS8: a derivative of Rhodococcus rhodochrous]. Office of Scientific and Technical Information (OSTI), January 1991. http://dx.doi.org/10.2172/5792251.

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