scholarly journals Transcriptomic Analysis Reveals a Bifurcated Terephthalate Degradation Pathway in Rhodococcus sp. Strain RHA1

2006 ◽  
Vol 189 (5) ◽  
pp. 1641-1647 ◽  
Author(s):  
Hirofumi Hara ◽  
Lindsay D. Eltis ◽  
Julian E. Davies ◽  
William W. Mohn
Keyword(s):  
Aromatic Compounds ◽  
Degradation Pathway ◽  
Transcriptomic Analysis ◽  
Ring Cleavage ◽  
Wide Range ◽  
Genes Encoding ◽  
Catechol 1,2 Dioxygenase ◽  
Rhodococcus Sp ◽  
Dioxygenase Activity ◽  
In Cells

ABSTRACT Phthalate isomers and their esters are important pollutants whose biodegradation is not well understood. Rhodococcus sp. strain RHA1 is notable for its ability to degrade a wide range of aromatic compounds. RHA1 was previously shown to degrade phthalate (PTH) and to have genes putatively encoding terephthalate (TPA) degradation. Transcriptomic analysis of 8,213 genes indicated that 150 were up-regulated during growth on PTH and that 521 were up-regulated during growth on TPA. Distinct ring cleavage dioxygenase systems were differentially expressed during growth on PTH and TPA. Genes encoding the protocatechuate (PCA) pathway were induced on both substrates, while genes encoding the catechol branch of the PCA pathway were additionally induced only on TPA. Accordingly, protocatechuate-3,4-dioxygenase activity was induced in cells grown on both substrates, while catechol-1,2-dioxygenase activity was induced only in cells grown on TPA. Knockout analysis indicated that pcaL, encoding 3-oxoadipate enol-lactone hydrolase and 4-carboxymuconolactone decarboxylase, was required for growth on both substrates but that pcaB, encoding β-carboxy-cis,cis-muconate lactonizing enzyme, was required for growth on PTH only. These results indicate that PTH is degraded solely via the PCA pathway, whereas TPA is degraded via a bifurcated pathway that additionally includes the catechol branch of the PCA pathway.

scholarly journals Key Aromatic-Ring-Cleaving Enzyme, Protocatechuate 3,4-Dioxygenase, in the Ecologically Important MarineRoseobacter Lineage

2000 ◽  
Vol 66 (11) ◽  
pp. 4662-4672 ◽  
Author(s):  
Alison Buchan ◽  
Lauren S. Collier ◽  
Ellen L. Neidle ◽  
Mary Ann Moran
Keyword(s):  
Aromatic Compounds ◽  
Southern Hybridization ◽  
Ring Cleavage ◽  
Degenerate Pcr ◽  
Cell Extracts ◽  
Aromatic Compound Degradation ◽  
Genes Encoding ◽  
Cleavage Enzyme ◽  
Key Enzyme ◽  
Dioxygenase Activity

ABSTRACT Aromatic compound degradation in six bacteria representing an ecologically important marine taxon of the α-proteobacteria was investigated. Initial screens suggested that isolates in theRoseobacter lineage can degrade aromatic compounds via the β-ketoadipate pathway, a catabolic route that has been well characterized in soil microbes. Six Roseobacter isolates were screened for the presence of protocatechuate 3,4-dioxygenase, a key enzyme in the β-ketoadipate pathway. All six isolates were capable of growth on at least three of the eight aromatic monomers presented (anthranilate, benzoate, p-hydroxybenzoate, salicylate, vanillate, ferulate, protocatechuate, and coumarate). Four of the Roseobacter group isolates had inducible protocatechuate 3,4-dioxygenase activity in cell extracts when grown onp-hydroxybenzoate. The pcaGH genes encoding this ring cleavage enzyme were cloned and sequenced from two isolates,Sagittula stellata E-37 and isolate Y3F, and in both cases the genes could be expressed in Escherichia coli to yield dioxygenase activity. Additional genes involved in the protocatechuate branch of the β-ketoadipate pathway (pcaC,pcaQ, and pobA) were found to cluster withpcaGH in these two isolates. Pairwise sequence analysis of the pca genes revealed greater similarity between the twoRoseobacter group isolates than between genes from eitherRoseobacter strain and soil bacteria. A degenerate PCR primer set targeting a conserved region within PcaH successfully amplified a fragment of pcaH from two additionalRoseobacter group isolates, and Southern hybridization indicated the presence of pcaH in the remaining two isolates. This evidence of protocatechuate 3,4-dioxygenase and the β-ketoadipate pathway was found in all six Roseobacterisolates, suggesting widespread abilities to degrade aromatic compounds in this marine lineage.

scholarly journals Novel Pathway for the Degradation of 2-Chloro-4-Nitrobenzoic Acid by Acinetobacter sp. Strain RKJ12

2011 ◽  
Vol 77 (18) ◽  
pp. 6606-6613 ◽  
Author(s):  
Dhan Prakash ◽  
Ravi Kumar ◽  
R. K. Jain ◽  
B. N. Tiwary
Keyword(s):  
Salicylic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Sole Source ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Muconic Acid ◽  
Content Type ◽  
Nitrobenzoic Acid ◽  
Catabolic Genes ◽  
Catechol 1,2 Dioxygenase

ABSTRACTThe organismAcinetobactersp. RKJ12 is capable of utilizing 2-chloro-4-nitrobenzoic acid (2C4NBA) as a sole source of carbon, nitrogen, and energy. In the degradation of 2C4NBA by strain RKJ12, various metabolites were isolated and identified by a combination of chromatographic, spectroscopic, and enzymatic activities, revealing a novel assimilation pathway involving both oxidative and reductive catabolic mechanisms. The metabolism of 2C4NBA was initiated by oxidativeorthodehalogenation, leading to the formation of 2-hydroxy-4-nitrobenzoic acid (2H4NBA), which subsequently was metabolized into 2,4-dihydroxybenzoic acid (2,4-DHBA) by a mono-oxygenase with the concomitant release of chloride and nitrite ions. Stoichiometric analysis indicated the consumption of 1 mol O2per conversion of 2C4NBA to 2,4-DHBA, ruling out the possibility of two oxidative reactions. Experiments with labeled H218O and18O2indicated the involvement of mono-oxygenase-catalyzed initial hydrolytic dechlorination and oxidative denitration mechanisms. The further degradation of 2,4-DHBA then proceeds via reductive dehydroxylation involving the formation of salicylic acid. In the lower pathway, the organism transformed salicylic acid into catechol, which was mineralized by theorthoring cleavage catechol-1,2-dioxygenase tocis, cis-muconic acid, ultimately forming tricarboxylic acid cycle intermediates. Furthermore, the studies carried out on a 2C4NBA−derivative and a 2C4NBA+transconjugant demonstrated that the catabolic genes for the 2C4NBA degradation pathway possibly reside on the ∼55-kb transmissible plasmid present in RKJ12.

scholarly journals Nitrobenzoates and Aminobenzoates Are Chemoattractants for Pseudomonas Strains

2004 ◽  
Vol 70 (1) ◽  
pp. 285-292 ◽  
Author(s):  
Rebecca E. Parales
Keyword(s):  
Pseudomonas Putida ◽  
Aromatic Compounds ◽  
Carbon Sources ◽  
Chemotactic Response ◽  
Aromatic Acids ◽  
Wide Range ◽  
Catechol 1,2 Dioxygenase ◽  
Sense And Respond ◽  
Chemotaxis System ◽  
Broad Specificity

ABSTRACT Three Pseudomonas strains were tested for the ability to sense and respond to nitrobenzoate and aminobenzoate isomers in chemotaxis assays. Pseudomonas putida PRS2000, a strain that grows on benzoate and 4-hydroxybenzoate by using the β-ketoadipate pathway, has a well-characterized β-ketoadipate-inducible chemotactic response to aromatic acids. PRS2000 was chemotactic to 3- and 4-nitrobenzoate and all three isomers of aminobenzoate when grown under conditions that induce the benzoate chemotactic response. P. putida TW3 and Pseudomonas sp. strain 4NT grow on 4-nitrotoluene and 4-nitrobenzoate by using the ortho (β-ketoadipate) and meta pathways, respectively, to complete the degradation of protocatechuate derived from 4-nitrotoluene and 4-nitrobenzoate. However, based on results of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase assays, both strains were found to use the β-ketoadipate pathway for the degradation of benzoate. Both strains were chemotactic to benzoate, 3- and 4-nitrobenzoate, and all three aminobenzoate isomers after growth with benzoate but not succinate. Strain TW3 was chemotactic to the same set of aromatic compounds after growth with 4-nitrotoluene or 4-nitrobenzoate. In contrast, strain 4NT did not respond to any aromatic acids when grown with 4-nitrotoluene or 4-nitrobenzoate, apparently because these substrates are not metabolized to the inducer (β-ketoadipate) of the chemotaxis system. The results suggest that strains TW3 and 4NT have a β-ketoadipate-inducible chemotaxis system that responds to a wide range of aromatic acids and is quite similar to that present in PRS2000. The broad specificity of this chemotaxis system works as an advantage in strains TW3 and 4NT because it functions to detect diverse carbon sources, including 4-nitrobenzoate.

Mutagenesis of catA from Pseudomonas sp. B3-1 to Enhance Catechol Accumulation

2012 ◽  
Vol 550-553 ◽  
pp. 1615-1620
Author(s):  
Jian Wen Xiong ◽  
Xian Lai Tang ◽  
Jun Fang Li ◽  
Min Zhang ◽  
Pei Hong Shen
Keyword(s):  
Aromatic Compounds ◽  
Sodium Benzoate ◽  
Conversion Rate ◽  
Wild Strain ◽  
Pseudomonas Sp ◽  
Maximal Amount ◽  
Molar Basis ◽  
Catechol 1,2 Dioxygenase ◽  
Dioxygenase Activity

Pseudomonas sp. B3-1, a wild strain isolated from soil, produced catechol from benzoate and accumulated it outside the cell. catA, a gene encodes a catechol 1,2-dioxygenase in the bioconversion of aromatic compounds, plays the central role in accumulation of catechol. Mutant of the catA gene is disrupted without blocking the transcription of downstream genes was analyzed. The result showed that the mutant had less catechol 1, 2-dioxygenase activity, only 1/3 of strain B3-1’s. The mutant produced a maximal amount of catechol (1.22 mg/ml) from 4 mg/ml of sodium benzoate after growing for 48 h. The conversion rate of benzoate to catechol was 51.5% on a molar basis.

scholarly journals Transcriptomic Assessment of Isozymes in the Biphenyl Pathway of Rhodococcus sp. Strain RHA1

2006 ◽  
Vol 72 (9) ◽  
pp. 6183-6193 ◽  
Author(s):  
Edmilson R. Gon�alves ◽  
Hirofumi Hara ◽  
Daisuke Miyazawa ◽  
Julian E. Davies ◽  
Lindsay D. Eltis ◽  
...  
Keyword(s):  
Dna Microarray ◽  
Aromatic Compounds ◽  
Regulatory Mechanism ◽  
Sequence Analyses ◽  
Catabolic Enzymes ◽  
Catabolic Genes ◽  
Genes Encoding ◽  
Pcr Assays ◽  
Alkyl Benzenes ◽  
Rhodococcus Sp

ABSTRACT Rhodococcus sp. RHA1 grows on a broad range of aromatic compounds and vigorously degrades polychlorinated biphenyls (PCBs). Previous work identified RHA1 genes encoding multiple isozymes for most of the seven steps of the biphenyl (BPH) pathway, provided evidence for coexpression of some of these isozymes, and indicated the involvement of some of these enzymes in the degradation of BPH, ethylbenzene (ETB), and PCBs. To investigate the expression of these isozymes and better understand how they contribute to the robust degradative capacity of RHA1, we comprehensively analyzed the 9.7-Mb genome of RHA1 for BPH pathway genes and characterized the transcriptome of RHA1 growing on benzoate (BEN), BPH, and ETB. Sequence analyses revealed 54 potential BPH pathway genes, including 28 not previously reported. Transcriptomic analysis with a DNA microarray containing 70-mer probes for 8,213 RHA1 genes revealed a suite of 320 genes of diverse functions that were upregulated during growth both on BPH and on ETB, relative to growth on the control substrate, pyruvate. By contrast, only 65 genes were upregulated during growth on BEN. Quantitative PCR assays confirmed microarray results for selected genes and indicated that some of the catabolic genes were upregulated over 10,000-fold. Our analysis suggests that up to 22 enzymes, including 8 newly identified ones, may function in the BPH pathway of RHA1. The relative expression levels of catabolic genes did not differ for BPH and ETB, suggesting a common regulatory mechanism. This study delineated a suite of catabolic enzymes for biphenyl and alkyl-benzenes in RHA1, which is larger than previously recognized and which may serve as a model for catabolism in other environmentally important bacteria having large genomes.

scholarly journals Identification and Characterization of Genes Involved in the Downstream Degradation Pathway of γ-Hexachlorocyclohexane in Sphingomonas paucimobilis UT26

2005 ◽  
Vol 187 (3) ◽  
pp. 847-853 ◽  
Author(s):  
Ryo Endo ◽  
Mayuko Kamakura ◽  
Keisuke Miyauchi ◽  
Masao Fukuda ◽  
Yoshiyuki Ohtsubo ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Gene Clusters ◽  
Sole Source ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Sphingomonas Paucimobilis ◽  
Reductase Gene ◽  
Chlorinated Aromatic Compounds ◽  
Identification And Characterization

ABSTRACT Sphingomonas paucimobilis UT26 utilizes γ-hexachlorocyclohexane (γ-HCH) as a sole source of carbon and energy. In our previous study, we cloned and characterized genes that are involved in the conversion of γ-HCH to maleylacetate (MA) via chlorohydroquinone (CHQ) in UT26. In this study, we identified and characterized an MA reductase gene, designated linF, that is essential for the utilization of γ-HCH in UT26. A gene named linEb, whose deduced product showed significant identity to LinE (53%), was located close to linF. LinE is a novel type of ring cleavage dioxygenase that catalyzes the conversion of CHQ to MA. LinEb expressed in Escherichia coli transformed CHQ and 2,6-dichlorohydroquinone to MA and 2-chloromaleylacetate, respectively. Our previous and present results indicate that UT26 (i) has two gene clusters for degradation of chlorinated aromatic compounds via hydroquinone-type intermediates and (ii) uses at least parts of both clusters for γ-HCH utilization.

3- and 4-alkylphenol degradation pathway in Pseudomonas sp. strain KL28: genetic organization of the lap gene cluster and substrate specificities of phenol hydroxylase and catechol 2,3-dioxygenase

Microbiology ◽  
2003 ◽  
Vol 149 (11) ◽  
pp. 3265-3277 ◽  
Author(s):  
Jae Jun Jeong ◽  
Ji Hyun Kim ◽  
Chi-Kyung Kim ◽  
Ingyu Hwang ◽  
Kyoung Lee
Keyword(s):  
Tca Cycle ◽  
Degradation Pathway ◽  
Phenol Hydroxylase ◽  
Chromosomal Dna ◽  
Promoter Assay ◽  
Substrate Preferences ◽  
Catabolic Genes ◽  
Wide Range ◽  
Genes Encoding ◽  
Tca Cycle Intermediates

The enzymes and genes responsible for the catabolism of higher alkylphenols have not been characterized in aerobic bacteria. Pseudomonas sp. strain KL28 can utilize a wide range of alkylphenols, which include the 4-n-alkylphenols (C1–C5). The genes, designated as lap (for long-chain alkylphenols), encoding enzymes for the catabolic pathway were cloned from chromosomal DNA and sequenced. The lap genes are located in a 13·2 kb region with 14 ORFs in the order lapRBKLMNOPCEHIFG and with the same transcriptional orientation. The lapR gene is transcribed independently and encodes a member of the XylR/DmpR positive transcriptional regulators. lapB, the first gene in the lap operon, encodes catechol 2,3-dioxygenase (C23O). The lapKLMNOP and lapCEHIFG genes encode a multicomponent phenol hydroxylase (mPH) and enzymes that degrade derivatives of 2-hydroxymuconic semialdehyde (HMS) to TCA cycle intermediates, respectively. The PlapB promoter contains motifs at positions −24(GG) and −12(GC) which are typically found in σ 54-dependent promoters. A promoter assay using a PlapB  : : gfp transcriptional fusion plasmid showed that lapB promoter activity is inducible and that it responds to a wide range of (alkyl)phenols. The structural genes encoding enzymes required for this catabolism are similar (42–69 %) to those encoded on a catabolic pVI150 plasmid from an archetypal phenol degrader, Pseudomonas sp. CF600. However, the lap locus does not include genes encoding HMS hydrolase and ferredoxin. The latter is known to be functionally associated with C23O for use of 4-alkylcatechols as substrates. The arrangement of the lap catabolic genes is not commonly found in other meta-cleavage operons. Substrate specificity studies show that mPH preferentially oxidizes 3- and 4-alkylphenols to 4-alkylcatechols. C23O preferentially oxidizes 4-alkylcatechols via proximal (2,3) cleavage. This indicates that these two key enzymes have unique substrate preferences and lead to the establishment of the initial steps of the lap pathway in strain KL28.

scholarly journals Benzoate Catabolite Repression of the Phthalate Degradation Pathway in Rhodococcus sp. Strain DK17

2006 ◽  
Vol 73 (4) ◽  
pp. 1370-1374 ◽  
Author(s):  
Ki Young Choi ◽  
Gerben J. Zylstra ◽  
Eungbin Kim
Keyword(s):  
Catabolite Repression ◽  
Detection Limits ◽  
Degradation Pathway ◽  
Substrate Utilization ◽  
Energy Sources ◽  
Mutant Strains ◽  
Genes Encoding ◽  
Rhodococcus Sp

ABSTRACT Rhodococcus sp. strain DK17 exhibits a catabolite repression-like response when provided simultaneously with benzoate and phthalate as carbon and energy sources. Benzoate in the medium is depleted to detection limits before the utilization of phthalate begins. The transcription of the genes encoding benzoate and phthalate dioxygenase paralleled the substrate utilization profile. Two mutant strains with defective benzoate dioxygenases were unable to utilize phthalate in the presence of benzoate, although they grew normally on phthalate in the absence of benzoate.

scholarly journals Complete genome sequence and Benzophenone-3 mineralisation potential of Rhodococcus sp. USK10, a bacterium isolated from riverbank sediment.

2021 ◽  
Author(s):  
Joseph Donald Martin ◽  
Urse Scheel Kruger ◽  
Athanasios Zervas ◽  
Morten Dencker Schostag ◽  
Tue Kjaergaard Nielsen ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Dna Sequences ◽  
Complete Genome ◽  
Aquatic Organisms ◽  
Degradation Pathway ◽  
Uv Filter ◽  
Degrading Bacterium ◽  
Wide Range ◽  
Mineralisation Potential ◽  
Rhodococcus Sp

Benzophenone-3 (BP3) is an organic UV filter whose presence in the aquatic environment has been linked to detrimental developmental impacts in aquatic organisms such as coral and fish. The genus Rhodococcus has been extensively studied and is known for possessing large genomes housing genes for biodegradation of a wide range of compounds, including aromatic carbons. Here, we present the genome sequence of Rhodococcus sp. USK10, which was isolated from Chinese riverbank sediment and is capable of utilising BP3 as the sole carbon source, resulting in full BP3 mineralisation. The genome consisted of 9,870,030 bp in 3 replicons, a G+C content of 67.2%, and 9,722 coding DNA sequences (CDSs). Annotation of the genome revealed that 179 of these CDSs are involved in metabolism of aromatic carbons. The complete genome of Rhodococcus sp. USK10 is the first complete, annotated genome sequence of a Benzophenone-3 degrading bacterium. Through radiolabelling, it is also the first bacterium proven to mineralise Benzophenone-3. Due to the widespread environmental prevalence of Benzophenone-3, coupled to its adverse impact on aquatic organisms, this characterisation provides an integral first step in better understanding the environmentally relevant degradation pathway of the commonly used UV filter. Given USK10's ability to completely mineralise Benzophenone-3, it could prove to be a suitable candidate for bioremediation application.

Regioselective Functionalization of N-Fused Heteroaromatics via FeCl3-Catalyzed Nucleophilic Addition to Activated N-Heterocycles

Synthesis ◽  
2020 ◽  
Author(s):  
Ikyon Kim ◽  
Sung June Kim ◽  
Sunhee Lee
Keyword(s):  
Aromatic Compounds ◽  
Nucleophilic Addition ◽  
Chemical Space ◽  
Wide Range ◽  
Regioselective Functionalization

AbstractBroadening of nitrogen-fused heteroaromatic chemical space such as indolizine and pyrrolo[1,2-a]pyrazine was achieved via FeCl­3-catalyzed nucleophilic addition of these N-fused aromatic compounds to a wide range of azolinium systems generated in situ, leading to novel N-fused heteroaromatic scaffolds with dearomatized N-heterocyclic substituents regioselectively. Nucleophilic addition of indolizines and pyrrolo[1,2-a]pyrazines mainly occurred at the C1 position of the isoquinoliniums and at the C4 site of the quinoliniums.

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