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Roles of UndA and MtrC of Shewanella putrefaciens W3-18-1 in iron reduction.

Yang Y, Chen J, Qiu D, Zhou J - BMC Microbiol. (2013)

Bottom Line: The ΔmtrC deletion mutant revealed significant deficiencies in reducing metals of Fe2O3, α-FeO(OH), β-FeO(OH), ferric citrate, Mn(IV) and Co(III), but not organic compounds.Nonetheless, undA deletion resulted in progressively slower iron reduction in the absence of mtrC and fitness loss under the iron-using condition, which was indicative of a functional role of UndA in iron reduction.These results provide physiological and biochemical evidences that UndA and MtrC of Shewanella putrefaciens W3-18-1 are involved in iron reduction.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China. yangyf@tsinghua.edu.cn.

ABSTRACT

Background: The completion of genome sequencing in a number of Shewanella species, which are most renowned for their metal reduction capacity, offers a basis for comparative studies. Previous work in Shewanella oneidensis MR-1 has indicated that some genes within a cluster (mtrBAC-omcA-mtrFED) were involved in iron reduction. To explore new features of iron reduction pathways, we experimentally analyzed Shewanella putrefaciens W3-18-1 since its gene cluster is considerably different from that of MR-1 in that the gene cluster encodes only four ORFs.

Results: Among the gene cluster, two genes (mtrC and undA) were shown to encode c-type cytochromes. The ΔmtrC deletion mutant revealed significant deficiencies in reducing metals of Fe2O3, α-FeO(OH), β-FeO(OH), ferric citrate, Mn(IV) and Co(III), but not organic compounds. In contrast, no deficiency of metal reduction was observed in the ΔundA deletion mutant. Nonetheless, undA deletion resulted in progressively slower iron reduction in the absence of mtrC and fitness loss under the iron-using condition, which was indicative of a functional role of UndA in iron reduction.

Conclusions: These results provide physiological and biochemical evidences that UndA and MtrC of Shewanella putrefaciens W3-18-1 are involved in iron reduction.

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The competition Assay for (A) wild-type (WT) vs. ΔundA and (B) ΔmtrC vs. ΔmtrC-undA. Relative abundances of each strain in the co-culture at Day 1, 3 and 7 are shown.
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Figure 4: The competition Assay for (A) wild-type (WT) vs. ΔundA and (B) ΔmtrC vs. ΔmtrC-undA. Relative abundances of each strain in the co-culture at Day 1, 3 and 7 are shown.

Mentions: To further demonstrate the functional role of UndA in iron reduction, competition assays were carried out to examine the fitness gain/loss caused by undA deletion. When wild-type and ∆undA cells were co-cultured in a medium with ferric citrate as the electron acceptor (Figure 4A), wild-type outcompeted ∆undA and gradually became dominant in the population by daily transfers. Similarly, ΔmtrC outcompeted ΔmtrC-undA (Figure 4B). These results indicated that UndA was needed to provide fitness advantage under iron-reducing conditions.


Roles of UndA and MtrC of Shewanella putrefaciens W3-18-1 in iron reduction.

Yang Y, Chen J, Qiu D, Zhou J - BMC Microbiol. (2013)

The competition Assay for (A) wild-type (WT) vs. ΔundA and (B) ΔmtrC vs. ΔmtrC-undA. Relative abundances of each strain in the co-culture at Day 1, 3 and 7 are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222724&req=5

Figure 4: The competition Assay for (A) wild-type (WT) vs. ΔundA and (B) ΔmtrC vs. ΔmtrC-undA. Relative abundances of each strain in the co-culture at Day 1, 3 and 7 are shown.
Mentions: To further demonstrate the functional role of UndA in iron reduction, competition assays were carried out to examine the fitness gain/loss caused by undA deletion. When wild-type and ∆undA cells were co-cultured in a medium with ferric citrate as the electron acceptor (Figure 4A), wild-type outcompeted ∆undA and gradually became dominant in the population by daily transfers. Similarly, ΔmtrC outcompeted ΔmtrC-undA (Figure 4B). These results indicated that UndA was needed to provide fitness advantage under iron-reducing conditions.

Bottom Line: The ΔmtrC deletion mutant revealed significant deficiencies in reducing metals of Fe2O3, α-FeO(OH), β-FeO(OH), ferric citrate, Mn(IV) and Co(III), but not organic compounds.Nonetheless, undA deletion resulted in progressively slower iron reduction in the absence of mtrC and fitness loss under the iron-using condition, which was indicative of a functional role of UndA in iron reduction.These results provide physiological and biochemical evidences that UndA and MtrC of Shewanella putrefaciens W3-18-1 are involved in iron reduction.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China. yangyf@tsinghua.edu.cn.

ABSTRACT

Background: The completion of genome sequencing in a number of Shewanella species, which are most renowned for their metal reduction capacity, offers a basis for comparative studies. Previous work in Shewanella oneidensis MR-1 has indicated that some genes within a cluster (mtrBAC-omcA-mtrFED) were involved in iron reduction. To explore new features of iron reduction pathways, we experimentally analyzed Shewanella putrefaciens W3-18-1 since its gene cluster is considerably different from that of MR-1 in that the gene cluster encodes only four ORFs.

Results: Among the gene cluster, two genes (mtrC and undA) were shown to encode c-type cytochromes. The ΔmtrC deletion mutant revealed significant deficiencies in reducing metals of Fe2O3, α-FeO(OH), β-FeO(OH), ferric citrate, Mn(IV) and Co(III), but not organic compounds. In contrast, no deficiency of metal reduction was observed in the ΔundA deletion mutant. Nonetheless, undA deletion resulted in progressively slower iron reduction in the absence of mtrC and fitness loss under the iron-using condition, which was indicative of a functional role of UndA in iron reduction.

Conclusions: These results provide physiological and biochemical evidences that UndA and MtrC of Shewanella putrefaciens W3-18-1 are involved in iron reduction.

Show MeSH
Related in: MedlinePlus