Inactivation of an iron transporter in Lactococcus lactis results in tellurite and oxidative stress

Turner, Mark S., Tan, Yu Pei and Giffard, Philip M. (2007) Inactivation of an iron transporter in Lactococcus lactis results in tellurite and oxidative stress. Applied and Environmental Microbiology, 73 19: 6144-6149. doi:10.1128/AEM.00413-07

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Author Turner, Mark S.
Tan, Yu Pei
Giffard, Philip M.
Title Inactivation of an iron transporter in Lactococcus lactis results in tellurite and oxidative stress
Journal name Applied and Environmental Microbiology   Check publisher's open access policy
ISSN 0099-2240
Publication date 2007-10
Year available 2007
Sub-type Article (original research)
DOI 10.1128/AEM.00413-07
Open Access Status File (Publisher version)
Volume 73
Issue 19
Start page 6144
End page 6149
Total pages 5
Place of publication Washington, D.C.
Publisher American Society for Microbiology
Language eng
Formatted abstract
In Lactococcus lactis, the interactions between oxidative defense, metal metabolism, and respiratory metabolism are not fully understood. To provide an insight into these processes, we isolated and characterized mutants of L. lactis resistant to the oxidizing agent tellurite (TeO32–), which generates superoxide radicals intracellularly. A collection of tellurite-resistant mutants was obtained using random transposon mutagenesis of L. lactis. These contained insertions in genes encoding a proton-coupled Mn2+/Fe2+ transport homolog (mntH), the high-affinity phosphate transport system (pstABCDEF), a putative osmoprotectant uptake system (choQ), and a homolog of the oxidative defense regulator spx (trmA). The tellurite-resistant mutants all had better survival than the wild type following aerated growth. The mntH mutant was found to be impaired in Fe2+ uptake, suggesting that MntH is a Fe2+ transporter in L. lactis. This mutant is capable of carrying out respiration but does not generate as high a final pH and does not exhibit the long lag phase in the presence of hemin and oxygen that is characteristic of wild-type L. lactis. This study suggests that tellurite-resistant mutants also have increased resistance to oxidative stress and that intracellular Fe2+ can heighten tellurite and oxygen toxicity.
Keyword Biotechnology & Applied Microbiology
Gram-positive Bacteria
Reactive Oxygen
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Agriculture and Food Sciences
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Citation counts: TR Web of Science Citation Count  Cited 22 times in Thomson Reuters Web of Science Article | Citations
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Created: Fri, 12 Dec 2008, 22:47:03 EST by Dr Mark Turner on behalf of School of Land, Crop and Food Sciences