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 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 Isolation and Characterization of a Novel p,p’-DDT-Degrading Bacterium: Aeromonas sp. Strain MY1 from Agricultural Soil

2020 ◽  
pp. 12-22
Author(s):  
Y. Murtala ◽  
B. C. Nwanguma ◽  
L. U. S. Ezeanyika
Keyword(s):  
Carbon Source ◽  
16S Rrna ◽  
Agricultural Soil ◽  
Sole Carbon Source ◽  
Phylogenetic Analyses ◽  
Inhibitory Effect ◽  
Aerobic Conditions ◽  
Degrading Bacterium ◽  
Isolation And Characterization

Background: Despite the banned on the use of dichlorodiphenyltrichloroethane (DDT) and other Persistent Organic Pollutants (POPs) by the Stockholm Convention for their toxicity, emerging shreds of evidence have indicated that DDT is, however, still in use in developing countries. This might increase the global burden of DDT contamination and its hazardous effects. Aim: This study focused on the isolation and characterization of p,p’-DDT-degrading bacterium from a tropical agricultural soil. Methodology: Standard isolation procedure was used for the screening and isolation of the strain. The 16S rRNA and phylogenetic analyses were used to identify the isolate and established protocols were followed to characterize the strain. Results: A new strain belonging to the genus Aeromonas was isolated from agricultural soil using minimal salt-p,p’-DDT enrichment medium. The 16S rRNA sequencing was used to identify the strain and the partial sequence was deposited in the NCBI GenBank as Aeromonas sp. Strain MY1. This mesophilic isolate was capable of utilizing up to 50 mgL-1 of p,p’-DDT as the sole carbon source at an optimum pH of 7.5 and optimum temperature of 35 °C within 120 h under aerobic conditions. Fe2+ (0.2 mgL-1) demonstrated a stimulatory effect on the p,p’-DDT degradation capacity by the strain MY1. However, Zn, Cu, Pb, Hg, Ag and Cr ions have demonstrated various patterns of inhibitory effect on the p,p’-DDT degradation capacity of the isolate at 0.2 mgL-1. The strain MY1 could be a promising candidate for the bioremediation of p,p’-DDT contaminant. Conclusion: Aeromonas sp. strain MY1 was capable of utilizing p,p’-DDT as a sole carbon source under aerobic conditions. The utilization capacity of the strain was influenced by some heavy metals. Fe was found to enhance the p,p’-DDT utilization capacity of the isolate at a lower concentration. While Zn, Cu, Pb, Hg, Ag and Cr showed various patterns of inhibitory effect.

scholarly journals Isolation and enzymatic characterization of fungal strains capable to use polyurethane as sole carbon source

2009 ◽  
Vol 25 ◽  
pp. S69
Author(s):  
A. Loredo-Treviño ◽  
J.A. Sánchez-Vasquez ◽  
R. Rodríguez-Herrera ◽  
C. Aguilar
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Enzymatic Characterization ◽  
Fungal Strains

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 Production and Characterization of Polyhydroxybutryrate Biopolymer from Azohydromonas australica Using Sucrose as a Sole Carbon Source

2017 ◽  
Vol 09 (03) ◽  
Author(s):  
Salman Ahmad ◽  
Abuzer Amir ◽  
Md Zafaryab ◽  
Khwaja Osama ◽  
Soban Ahmad Faridi ◽  
...  
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Azohydromonas Australica

scholarly journals Characterization of the β-Ketoadipate Pathway in Sinorhizobium meliloti

2006 ◽  
Vol 72 (8) ◽  
pp. 5403-5413 ◽  
Author(s):  
Allyson M. MacLean ◽  
Gordon MacPherson ◽  
Punita Aneja ◽  
Turlough M. Finan
Keyword(s):  
Aromatic Compounds ◽  
Related Species ◽  
Sinorhizobium Meliloti ◽  
Transcriptional Regulator ◽  
Transferase Activity ◽  
Catabolic Pathway ◽  
Closely Related Species ◽  
Coa Transferase ◽  
Transcriptional Units

ABSTRACT Aromatic compounds represent an important source of energy for soil-dwelling organisms. The β-ketoadipate pathway is a key metabolic pathway involved in the catabolism of the aromatic compounds protocatechuate and catechol, and here we show through enzymatic analysis and mutant analysis that genes required for growth and catabolism of protocatechuate in the soil-dwelling bacterium Sinorhizobium meliloti are organized on the pSymB megaplasmid in two transcriptional units designated pcaDCHGB and pcaIJF. The pcaD promoter was mapped by primer extension, and expression from this promoter is demonstrated to be regulated by the LysR-type protein PcaQ. β-Ketoadipate succinyl-coenzyme A (CoA) transferase activity in S. meliloti was shown to be encoded by SMb20587 and SMb20588, and these genes have been renamed pcaI and pcaJ, respectively. These genes are organized in an operon with a putative β-ketoadipyl-CoA thiolase gene (pcaF), and expression of the pcaIJF operon is shown to be regulated by an IclR-type transcriptional regulator, SMb20586, which we have named pcaR. We show that pcaR transcription is negatively autoregulated and that PcaR is a positive regulator of pcaIJF expression and is required for growth of S. meliloti on protocatechuate as the carbon source. The characterization of the protocatechuate catabolic pathway in S. meliloti offers an opportunity for comparison with related species, including Agrobacterium tumefaciens. Differences observed between S. meliloti and A. tumefaciens pcaIJ offer the first evidence of pca genes that may have been acquired after speciation in these closely related species.

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