scholarly journals Megaplasmid and Chromosomal Loci for the PHB Degradation Pathway in Rhizobium (Sinorhizobium) meliloti

Genetics ◽  
1997 ◽  
Vol 146 (4) ◽  
pp. 1211-1220 ◽  
Author(s):  
Trevor C Charles ◽  
Guo-qin Cai ◽  
Punita Aneja
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Sinorhizobium Meliloti ◽  
Rhizobium Meliloti ◽  
Glyoxylate Cycle ◽  
Degradation Pathway ◽  
Cosmid Library ◽  
Insertion Mutagenesis ◽  
Transcriptional Units ◽  
Chromosomal Loci

Chromosomal and megaplasmid loci that affect the poly-3-hydroxybutyrate (PHB) degradation pathway in Rhizobium meliloti were identified. A clone that restores the ability of certain R. meliloti mutants with defined deletions in megaplasmid pRmeSU47b to use 3-hydroxybutyrate or acetoacetate as the sole carbon source was isolated from a cosmid library of R. meliloti genomic DNA. Tn5 insertion mutagenesis, followed by merodiploid complementation analysis, demonstrated that the locus consists of at least four transcriptional units, bhbA-D. We also identified loci involved in 3-hydroxybutyrate and/or acetoacetate utilization by screening for mutants that had lost the ability to use 3-hydroxybutyrate as the sole carbon source while retaining the ability to use acetate (thus ensuring an intact glyoxylate cycle and gluconeogenic pathway). These mutants fell into four classes, as determined by replicon mobilization experiments and genetic linkage in phage transduction; one class corresponded to the bhb locus on pRmeSU47b, two classes mapped to different regions on the chromosome and the fourth, bdhA, represented by a single mutant, mapped to another pRmeSU47b locus, near bacA. The bdhA mutant is deficient in 3-hydroxybutrate dehydrogenase activity.

scholarly journals A locus necessary for the transport and catabolism of erythritol in Sinorhizobium meliloti

Microbiology ◽  
2010 ◽  
Vol 156 (10) ◽  
pp. 2970-2981 ◽  
Author(s):  
Barney A. Geddes ◽  
Brad S. Pickering ◽  
Nathan J. Poysti ◽  
Heather Collins ◽  
Harry Yudistira ◽  
...  
Keyword(s):  
Carbon Source ◽  
Abc Transporter ◽  
Sole Carbon Source ◽  
Sinorhizobium Meliloti ◽  
Genetic Complementation ◽  
Rt Pcr ◽  
Catabolic Genes ◽  
Transcriptional Units ◽  
Six Genes

In this work we have genetically defined an erythritol utilization locus in Sinorhizobium meliloti. A cosmid containing the locus was isolated by complementation of a transposon mutant and was subsequently mutagenized using Tn5 : : B20. The locus was found to consist of five transcriptional units, each of which was necessary for the utilization of erythritol. Genetic complementation experiments using genes putatively annotated as erythritol catabolic genes clearly showed that, of the 17 genes at this locus, six genes are not necessary for the utilization of erythritol as a sole carbon source. The remaining genes encode EryA, EryB, EryC and TpiB as well as an uncharacterized ABC-type transporter. Transport experiments using labelled erythritol showed that components of the ABC transporter are necessary for the uptake of erythritol. The locus also contains two regulators: EryD, a SorC class regulator, and SMc01615, a DeoR class regulator. Quantitative RT-PCR experiments showed that each of these regulators negatively regulates its own transcription. In addition, induction of the erythritol locus was dependent upon EryD and a product of erythritol catabolism. Further characterization of polar mutations revealed that in addition to erythritol, the locus contains determinants for adonitol and l-arabitol utilization. The context of the mutations suggests that the locus is important for both the transport and catabolism of adonitol and l-arabitol.

scholarly journals Mycobacterium tuberculosis Is Able To Accumulate and Utilize Cholesterol

2009 ◽  
Vol 191 (21) ◽  
pp. 6584-6591 ◽  
Author(s):  
Anna Brzostek ◽  
Jakub Pawelczyk ◽  
Anna Rumijowska-Galewicz ◽  
Bozena Dziadek ◽  
Jaroslaw Dziadek
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Cytoplasmic Membrane ◽  
Degradation Pathway ◽  
Cholesterol Accumulation ◽  
Targeted Disruption ◽  
Future Studies

ABSTRACT It is expected that the obligatory human pathogen Mycobacterium tuberculosis must adapt metabolically to the various nutrients available during its cycle of infection, persistence, and reactivation. Cholesterol, which is an important part of the mammalian cytoplasmic membrane, is a potential energy source. Here, we show that M. tuberculosis grown in medium containing a carbon source other than cholesterol is able to accumulate cholesterol in the free-lipid zone of its cell wall. This cholesterol accumulation decreases the permeability of the cell wall for the primary antituberculosis drug, rifampin, and partially masks the mycobacterial surface antigens. Furthermore, M. tuberculosis was able to grow on mineral medium supplemented with cholesterol as the sole carbon source. Targeted disruption of the Rv3537 (kstD) gene inhibited growth due to inactivation of the cholesterol degradation pathway, as evidenced by accumulation of the intermediate, 9-hydroxy-4-androstene-3,17-dione. Our findings that M. tuberculosis is able to accumulate cholesterol in the presence of alternative nutrients and use it when cholesterol is the sole carbon source in vitro may facilitate future studies into the pathophysiology of this important deadly pathogen.

scholarly journals Inositol Catabolism, a Key Pathway in Sinorhizobium meliloti for Competitive Host Nodulation

2010 ◽  
Vol 76 (24) ◽  
pp. 7972-7980 ◽  
Author(s):  
Petra R. A. Kohler ◽  
Jasmine Y. Zheng ◽  
Elke Schoffers ◽  
Silvia Rossbach
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Sinorhizobium Meliloti ◽  
Mutational Analysis ◽  
Nodule Occupancy ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Catabolic Pathway ◽  
Inositol Dehydrogenase

ABSTRACT The nitrogen-fixing symbiont of alfalfa, Sinorhizobium meliloti, is able to use myo-inositol as the sole carbon source. Putative inositol catabolism genes (iolA and iolRCDEB) have been identified in the S. meliloti genome based on their similarities with the Bacillus subtilis iol genes. In this study, functional mutational analysis revealed that the iolA and iolCDEB genes are required for growth not only with the myo-isomer but also for growth with scyllo- and d-chiro-inositol as the sole carbon source. An additional, hypothetical dehydrogenase of the IdhA/MocA/GFO family encoded by the smc01163 gene was found to be essential for growth with scyllo-inositol, whereas the idhA-encoded myo-inositol dehydrogenase was responsible for the oxidation of d-chiro-inositol. The putative regulatory iolR gene, located upstream of iolCDEB, encodes a repressor of the iol genes, negatively regulating the activity of the myo- and the scyllo-inositol dehydrogenases. Mutants with insertions in the iolA, smc01163, and individual iolRCDE genes could not compete against the wild type in a nodule occupancy assay on alfalfa plants. Thus, a functional inositol catabolic pathway and its proper regulation are important nutritional or signaling factors in the S. meliloti-alfalfa symbiosis.

scholarly journals Biodegradation and metabolic pathway of sulfamethoxazole by Sphingobacterium mizutaii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jinlong Song ◽  
Guijie Hao ◽  
Lu Liu ◽  
Hongyu Zhang ◽  
Dongxue Zhao ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Carbon Source ◽  
Human Health ◽  
Food Chain ◽  
Metabolic Pathway ◽  
Bacterial Strain ◽  
Sole Carbon Source ◽  
Degradation Pathway ◽  
Aquatic Animal ◽  
Animal Diseases

AbstractSulfamethoxazole (SMX) is the most commonly used antibiotic in worldwide for inhibiting aquatic animal diseases. However, the residues of SMX are difficult to eliminate and may enter the food chain, leading to considerable threats on human health. The bacterial strain Sphingobacterium mizutaii LLE5 was isolated from activated sludge. This strain could utilize SMX as its sole carbon source and degrade it efficiently. Under optimal degradation conditions (30.8 °C, pH 7.2, and inoculum amount of 3.5 × 107 cfu/mL), S. mizutaii LLE5 could degrade 93.87% of 50 mg/L SMX within 7 days. Four intermediate products from the degradation of SMX were identified and a possible degradation pathway based on these findings was proposed. Furthermore, S. mizutaii LLE5 could also degrade other sulfonamides. This study is the first report on (1) degradation of SMX and other sulfonamides by S. mizutaii, (2) optimization of biodegradation conditions via response surface methodology, and (3) identification of sulfanilamide, 4-aminothiophenol, 5-amino-3-methylisoxazole, and aniline as metabolites in the degradation pathway of SMX in a microorganism. This strain might be useful for the bioremediation of SMX-contaminated environment.

scholarly journals Biodegradation and Metabolic Pathway of Sulfamethoxazole by Sphingobacterium Mizutaii

2021 ◽  
Author(s):  
Jinlong Song ◽  
Guijie Hao ◽  
Lu Liu ◽  
Hongyu Zhang ◽  
Dongxue Zhao ◽  
...  
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Human Health ◽  
Food Chain ◽  
Metabolic Pathway ◽  
Bacterial Strain ◽  
Sole Carbon Source ◽  
Degradation Pathway ◽  
Aquatic Animal ◽  
Animal Diseases

Abstract Sulfamethoxazole (SMX) is the most commonly used antibiotics in China for inhibiting aquatic animal diseases. However, the residues of SMX are difficult to eliminate and may enter the food chain, leading to considerable threats on human health. The bacterial strain Sphingobacterium mizutaii LLE5 was isolated from activated sludge. This strain could utilize SMX as its sole carbon source and degrade it efficiently. Under optimal degradation conditions (30.8 °C, pH 7.2, and inoculum amount of 3.5 × 107 cfu/mL), S. mizutaii LLE5 could degrade 93.87% of 50 mg/L SMX within 7 days. Four intermediate products from the degradation of SMX were identified: sulfanilamide, 4-aminothiophenol, 5-amino-3-methylisoxazole, and aniline, suggesting a possible degradation pathway based on these findings. This report is the first to confirm that Sphingobacteriumi could degrade SMX. Furthermore, S. mizutaii LLE5 could also degrade other sulfonamides. The degradation efficiencies of strain LLE5 for sulfadiazine, sulfaguanidine, sulfamisoxazole, and sulfadimidine were 59.85%, 51.68%, 46.95%, and 37.42%, respectively.

scholarly journals Requirement for the Enzymes Acetoacetyl Coenzyme A Synthetase and Poly-3-Hydroxybutyrate (PHB) Synthase for Growth of Sinorhizobium meliloti on PHB Cycle Intermediates

2000 ◽  
Vol 182 (8) ◽  
pp. 2113-2118 ◽  
Author(s):  
Guo-qin Cai ◽  
Brian T. Driscoll ◽  
Trevor C. Charles
Keyword(s):  
Sinorhizobium Meliloti ◽  
Coenzyme A ◽  
Degradation Pathway ◽  
Synthetase Activity ◽  
Acetyl Coa ◽  
Putative Protein ◽  
Cell Extracts ◽  
Coa Transferase ◽  
Phb Synthase ◽  
Chromosomal Loci

ABSTRACT We have identified two Sinorhizobium melilotichromosomal loci affecting the poly-3-hydroxybutyrate degradation pathway. One locus was identified as the gene acsA, encoding acetoacetyl coenzyme A (acetoacetyl-CoA) synthetase. Analysis of the acsA nucleotide sequence revealed that this gene encodes a putative protein with a molecular weight of 72,000 that shows similarity to acetyl-CoA synthetase in other organisms. Acetyl-CoA synthetase activity was not affected in cell extracts of glucose-grown acsA::Tn5 mutants; instead, acetoacetyl-CoA synthetase activity was drastically reduced. These findings suggest that acetoacetyl-CoA synthetase, rather than CoA transferase, activates acetoacetate to acetoacetyl-CoA in the S. meliloti poly-3-hydroxybutyrate cycle. The second locus was identified as phbC, encoding poly-3-hydroxybutyrate synthase, and was found to be required for synthesis of poly-3-hydroxybutyrate deposits.

scholarly journals Poly-3-Hydroxybutyrate Degradation in Rhizobium (Sinorhizobium) meliloti: Isolation and Characterization of a Gene Encoding 3-Hydroxybutyrate Dehydrogenase

1999 ◽  
Vol 181 (3) ◽  
pp. 849-857 ◽  
Author(s):  
P. Aneja ◽  
T. C. Charles
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Sinorhizobium Meliloti ◽  
Transcriptional Start Site ◽  
Consensus Sequence ◽  
Start Codon ◽  
Start Site ◽  
Gene Encoding ◽  
Reading Frame ◽  
Isolation And Characterization

ABSTRACT We have cloned and sequenced the 3-hydroxybutyrate dehydrogenase-encoding gene (bdhA) from Rhizobium (Sinorhizobium) meliloti. The gene has an open reading frame of 777 bp that encodes a polypeptide of 258 amino acid residues (molecular weight 27,177, pI 6.07). The R. meliloti Bdh protein exhibits features common to members of the short-chain alcohol dehydrogenase superfamily. bdhA is the first gene transcribed in an operon that also includes xdhA, encoding xanthine oxidase/dehydrogenase. Transcriptional start site analysis by primer extension identified two transcription starts. S1, a minor start site, was located 46 to 47 nucleotides upstream of the predicted ATG start codon, while S2, the major start site, was mapped 148 nucleotides from the start codon. Analysis of the sequence immediately upstream of either S1 or S2 failed to reveal the presence of any known consensus promoter sequences. Although a ς54 consensus sequence was identified in the region between S1 and S2, a corresponding transcript was not detected, and a rpoN mutant of R. meliloti was able to utilize 3-hydroxybutyrate as a sole carbon source. The R. meliloti bdhA gene is able to confer uponEscherichia coli the ability to utilize 3-hydroxybutyrate as a sole carbon source. An R. meliloti bdhA mutant accumulates poly-3-hydroxybutyrate to the same extent as the wild type and shows no symbiotic defects. Studies with a strain carrying alacZ transcriptional fusion to bdhAdemonstrated that gene expression is growth phase associated.

scholarly journals Role of Sinorhizobium meliloti and Escherichia coli Long-Chain Acyl-CoA Synthetase FadD in Long-Term Survival

2020 ◽  
Vol 8 (4) ◽  
pp. 470
Author(s):  
Ángel de la Cruz Pech-Canul ◽  
Geovanny Rivera-Hernández ◽  
Joaquina Nogales ◽  
Otto Geiger ◽  
María J. Soto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Carbon Source ◽  
Stationary Phase ◽  
Sole Carbon Source ◽  
Sinorhizobium Meliloti ◽  
Membrane Lipids ◽  
Term Survival ◽  
Long Chain

FadD is an acyl-coenzyme A (CoA) synthetase specific for long-chain fatty acids (LCFA). Strains mutated in fadD cannot produce acyl-CoA and thus cannot grow on exogenous LCFA as the sole carbon source. Mutants in the fadD (smc02162) of Sinorhizobium meliloti are unable to grow on oleate as the sole carbon source and present an increased surface motility and accumulation of free fatty acids at the entry of the stationary phase of growth. In this study, we found that constitutive expression of the closest FadD homologues of S. meliloti, encoded by sma0150 and smb20650, could not revert any of the mutant phenotypes. In contrast, the expression of Escherichia coli fadD could restore the same functions as S. meliloti fadD. Previously, we demonstrated that FadD is required for the degradation of endogenous fatty acids released from membrane lipids. Here, we show that absence of a functional fadD provokes a significant loss of viability in cultures of E. coli and of S. meliloti in the stationary phase, demonstrating a crucial role of fatty acid degradation in survival capacity.

scholarly journals Biodegradation of 3,5,6-trichloro-2-pyridinol by Cupriavidus sp. DT-1 in liquid and soil enviroments

2019 ◽  
Author(s):  
Peng Lu ◽  
Ai-min Liu ◽  
Hong-ming Liu ◽  
Jian-zhong Wang
Keyword(s):  
Carbon Source ◽  
Contaminated Soils ◽  
Sole Carbon Source ◽  
Degradation Rate ◽  
Marker Gene ◽  
Degradation Pathway ◽  
High Concentration ◽  
Viability Test ◽  
Fluorescent Marker ◽  
Maleamic Acid

Abstract The bactrial strain Cupriavidus sp. DT-1 can degrade 3,5,6-trichloro-2-pyridinol (TCP) and transform it into 2-hydroxypyridine (2-HP). This is a unique degradation pathway of TCP but incomplete. In the present study, strain DT-1 could degrade 2-HP at a high concentration 500 mg/L and use it as sole carbon source for growth. Three metabolites (nicotine blue, maleamic acid and fumaric acid) were detected in the medium and the complete degradation pathway of TCP was derived. Inoculation of TCP-contaminated soils with strain DT-1 resulted in a degradation rate 94.4% and 86.7% as compared to 20.4% and 28.4% in uninoculated soils, respectively. Fluorescent marker gene gfp was introduced into strain DT-1 and a new strain DT-1- gfp was created, viability test showed the strain could survive well in soils for more than 35 d. This finding suggests that strain DT-1 has potential for use in bioremediation of TCP-contaminated environments.

scholarly journals Cinnamic Acid, an Autoinducer of Its Own Biosynthesis, Is Processed via Hca Enzymes in Photorhabdus luminescens

2008 ◽  
Vol 74 (6) ◽  
pp. 1717-1725 ◽  
Author(s):  
Sabina Chalabaev ◽  
Evelyne Turlin ◽  
Sylvie Bay ◽  
Christelle Ganneau ◽  
Emma Brito-Fravallo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Cinnamic Acid ◽  
Aromatic Compounds ◽  
Sole Carbon Source ◽  
Biosynthetic Pathway ◽  
Phenylalanine Ammonia Lyase ◽  
Carbon Sources ◽  
Degradation Pathway ◽  
Photorhabdus Luminescens

ABSTRACT Photorhabdus luminescens, an entomopathogenic bacterium and nematode symbiont, has homologues of the Hca and Mhp enzymes. In Escherichia coli, these enzymes catalyze the degradation of the aromatic compounds 3-phenylpropionate (3PP) and cinnamic acid (CA) and allow the use of 3PP as sole carbon source. P. luminescens is not able to use 3PP and CA as sole carbon sources but can degrade them. Hca dioxygenase is involved in this degradation pathway. P. luminescens synthesizes CA from phenylalanine via a phenylalanine ammonia-lyase (PAL) and degrades it via the not-yet-characterized biosynthetic pathway of 3,5-dihydroxy-4-isopropylstilbene (ST) antibiotic. CA induces its own synthesis by enhancing the expression of the stlA gene that codes for PAL. P. luminescens bacteria release endogenous CA into the medium at the end of exponential growth and then consume it. Hca dioxygenase is involved in the consumption of endogenous CA but is not required for ST production. This suggests that CA is consumed via at least two separate pathways in P. luminescens: the biosynthesis of ST and a pathway involving the Hca and Mhp enzymes.

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