Chromosome mapping in Alealigenes eutrophus CH34

Sadouk, A.; Mergeay, Max

doi:10.1007/bf00277055

Cited by 30 publications

(26 citation statements)

References 22 publications

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“…This is an indication that the genes involved in alcaligin E biosynthesis and ferric iron-alcaligin E transport are organized in a gene cluster. Evidence that these genes are located near the cys-232 locus on the chromosomal map of A. eutrophus CH34 was found (43), in accordance with the observation of a cysM-or cysK-like gene downstream of aleB.…”

Section: Discussionsupporting

confidence: 83%

Siderophore-mediated iron uptake in Alcaligenes eutrophus CH34 and identification of aleB encoding the ferric iron-alcaligin E receptor

et al. 1996

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Siderophore production in response to iron limitation was observed in Alcaligenes eutrophus CH34, and the corresponding siderophore was named alcaligin E. Alcaligin E was characterized as a phenolate-type siderophore containing neither catecholate nor hydroxamate groups. Alcaligin E promoted the growth of siderophore-deficient A. eutrophus mutants under iron-restricted conditions and promoted 59 Fe uptake by ironlimited cells. However, the growth of the Sid ؊ mutant AE1152, which was obtained from CH34 by Tn5-Tc mutagenesis, was completely inhibited by the addition of alcaligin E. AE1152 also showed strongly reduced 59 Fe uptake in the presence of alcaligin E. This indicates that a gene, designated aleB, which is involved in transport of ferric iron-alcaligin E across the membrane is inactivated. The aleB gene was cloned, and its putative amino acid sequence showed strong similarity to those of ferric iron-siderophore receptor proteins. Both wild-type strain CH34 and aleB mutant AE1152 were able to use the same heterologous siderophores, indicating that AleB is involved only in ferric iron-alcaligin E uptake. Interestingly, no utilization of pyochelin, which is also a phenolate-type siderophore, was observed for A. eutrophus CH34. Genetic studies of different Sid ؊ mutants, obtained after transposon mutagenesis, showed that the genes involved in alcaligin E and ferric iron-alcaligin E receptor biosynthesis are clustered in a 20-kb region on the A. eutrophus CH34 chromosome in the proximity of the cys-232 locus.Iron, the fourth most abundant element in the earth's crust, forms insoluble ferric hydroxide complexes under aerobic conditions and at neutral pH, thus severely restricting the bioavailability of this metal. In virtually all microorganisms, iron plays an irreplaceable role as cofactor for a variety of functional proteins and enzymes. Therefore, microorganisms have evolved specialized high-affinity transport systems in order to obtain sufficient amounts of this essential element. Most bacteria have the ability to produce and excrete siderophores, small compounds exhibiting very high affinity for ferric iron (33). A cognate-specific transport system mediates the uptake of the ferric iron-siderophore complex into the cell (16, 34). Many microorganisms are also able to utilize iron complexed to siderophores produced by other bacterial or fungal species. In general, the biosynthesis of the siderophore and associated transport machinery is initiated under conditions of iron limitation.Metal-tolerant Alcaligenes eutrophus strains are a group of strongly related strains that are well adapted to environments containing high levels of heavy metals. A. eutrophus CH34 is the main representative and the most studied strain of this group. It harbors two megaplasmids, pMOL28 and pMOL30, which carry multiple resistance determinants to different heavy metals (7,26). Among the best characterized is the czc operon of pMOL30, which determines resistance to Co, Cd, and Zn by a chemiosmotic cation/proton-antiporter efflux syst...

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Section: Discussionsupporting

confidence: 83%

Siderophore-mediated iron uptake in Alcaligenes eutrophus CH34 and identification of aleB encoding the ferric iron-alcaligin E receptor

et al. 1996

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“…37°C instead of 30°C. This phenomenon is referred to as temperature induced mutagenesis in which survivor cells appear to have undergone DNA arrangements, insertions, or deletions [6], [22], [77], [78]. One well studied case is the integration of a 44 kb DNA fragment in the pMOL28 plasmid and the identification of IS 1086 particpating in this event [77], [79].…”

Section: Resultsmentioning

confidence: 99%

“…One well studied case is the integration of a 44 kb DNA fragment in the pMOL28 plasmid and the identification of IS 1086 particpating in this event [77], [79]. The resulting plasmid pMOL50 has a much higher conjugation frequency then either pMOL28 or pMOL30 and is able to very efficiently (retro)mobilise very large DNA fragments from the CH34 chromosome (of up to 1 Mb), a property that was exploited to construct the genetic map of the CH34 main chromosome, CHR1 [22].…”

Section: Resultsmentioning

confidence: 99%

“…First, upon its discovery, strain CH34 was described as a good acceptor of foreign genes in homologous and heterospecific matings that involved the broad host range IncP plasmid RP4::miniMu (aka pULB113) containing a very efficient transposon (prophage miniMu3A). This transposon promotes the generation of R-prime plasmids via an “ in vivo ” cloning process [19], [20] later used to map the largest chromosome of C. metallidurans CH34 [21], [22]. Second, strain CH34 is a good recipient of large plasmids that are involved in the HMR or hydrogenotrophy of other Cupriavidus strains [23].…”

Section: Introductionmentioning

confidence: 99%

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The Complete Genome Sequence of Cupriavidus metallidurans Strain CH34, a Master Survivalist in Harsh and Anthropogenic Environments

et al. 2010

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Many bacteria in the environment have adapted to the presence of toxic heavy metals. Over the last 30 years, this heavy metal tolerance was the subject of extensive research. The bacterium Cupriavidus metallidurans strain CH34, originally isolated by us in 1976 from a metal processing factory, is considered a major model organism in this field because it withstands milli-molar range concentrations of over 20 different heavy metal ions. This tolerance is mostly achieved by rapid ion efflux but also by metal-complexation and -reduction. We present here the full genome sequence of strain CH34 and the manual annotation of all its genes. The genome of C. metallidurans CH34 is composed of two large circular chromosomes CHR1 and CHR2 of, respectively, 3,928,089 bp and 2,580,084 bp, and two megaplasmids pMOL28 and pMOL30 of, respectively, 171,459 bp and 233,720 bp in size. At least 25 loci for heavy-metal resistance (HMR) are distributed over the four replicons. Approximately 67% of the 6,717 coding sequences (CDSs) present in the CH34 genome could be assigned a putative function, and 9.1% (611 genes) appear to be unique to this strain. One out of five proteins is associated with either transport or transcription while the relay of environmental stimuli is governed by more than 600 signal transduction systems. The CH34 genome is most similar to the genomes of other Cupriavidus strains by correspondence between the respective CHR1 replicons but also displays similarity to the genomes of more distantly related species as a result of gene transfer and through the presence of large genomic islands. The presence of at least 57 IS elements and 19 transposons and the ability to take in and express foreign genes indicates a very dynamic and complex genome shaped by evolutionary forces. The genome data show that C. metallidurans CH34 is particularly well equipped to live in extreme conditions and anthropogenic environments that are rich in metals.

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“…When required, 1.5 % agar (w/v) was added to the liquid medium to prepare the solid medium. MIC was determined in tris mineral medium at low phosphate content (0.12 g L -1 of Na 2 HPO 4 ) to avoid heavy metal precipitation (Sadouk and Mergeay 1993), supplemented with 0.6 % (w/v) gluconate (TMMG) and containing different concentrations of heavy metals: NiCl 2 , ZnSO 4 , CuSO 4 , CdSO 4 and HgCl 2 . For inoculation, the isolated strains were grown in TSB 0.19 medium at 30°C.…”

Section: Bacterial Strains and Growth Conditionsmentioning

confidence: 99%

Rhizosphere colonization and arsenic translocation in sunflower (Helianthus annuus L.) by arsenate reducing Alcaligenes sp. strain Dhal-L

Cavalca

Corsini

Bachate

et al. 2013

World J Microbiol Biotechnol

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In the present study, six arsenic-resistant strains previously isolated were tested for their plant growth promoting characteristics and heavy metal resistance, in order to choose one model strain as an inoculum for sunflower plants in pot experiments. The aim was to investigate the effect of arsenic-resistant strain on sunflower growth and on arsenic uptake from arsenic contaminated soil. Based on plant growth promoting characteristics and heavy metal resistance, Alcaligenes sp. strain Dhal-L was chosen as an inoculum. Beside the ability to reduce arsenate to arsenite via an Ars operon, the strain exhibited 1-amino-cyclopropane-1-carboxylic acid deaminase activity and it was also able to produce siderophore and indole acetic acid. Pot experiments were conducted with an agricultural soil contaminated with arsenic (214 mg kg -1 ). A real time PCR method was set up based on the quantification of ACR3(2) type of arsenite efflux pump carried by Alcaligenes sp. strain Dhal-L, in order to monitor presence and colonisation of the strain in the bulk and rhizospheric soil. As a result of strain inoculation, arsenic uptake by plants was increased by 53 %, whereas ACR3(2) gene copy number in rhizospheric soil was 100 times higher in inoculated than in control pots, indicating the colonisation of strain. The results indicated that the presence of arsenate reducing strains in the rhizosphere of sunflower influences arsenic mobilization and promotes arsenic uptake by plant.

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Chromosome mapping in Alealigenes eutrophus CH34

Cited by 30 publications

References 22 publications

Siderophore-mediated iron uptake in Alcaligenes eutrophus CH34 and identification of aleB encoding the ferric iron-alcaligin E receptor

Siderophore-mediated iron uptake in Alcaligenes eutrophus CH34 and identification of aleB encoding the ferric iron-alcaligin E receptor

The Complete Genome Sequence of Cupriavidus metallidurans Strain CH34, a Master Survivalist in Harsh and Anthropogenic Environments

Rhizosphere colonization and arsenic translocation in sunflower (Helianthus annuus L.) by arsenate reducing Alcaligenes sp. strain Dhal-L

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