michalczyk-bioinformaticande-2009.pdf (559.07 kB)
Bioinformatic and expression analyses of genes mediating zinc homeostasis in Nostoc punctiforme
journal contribution
posted on 2009-02-01, 00:00 authored by Lee Hudek, L Rai, David Freestone, Agnes MichalczykAgnes Michalczyk, Maria Gibson, Y Song, Leigh AcklandLeigh AcklandZinc homeostasis was investigated in Nostoc punctiforme. Cell tolerance to Zn2+ over 14 days showed that ZnCl2 levels above 22 µM significantly reduced cell viability. After 3 days in 22 µM ZnCl2, ca. 12% of the Zn2+ was in an EDTA-resistant component, suggesting an intracellular localization. Zinquin fluorescence was detected within cells exposed to concentrations up to 37 µM relative to 0 µM treatment. Radiolabeled 65Zn showed Zn2+ uptake increased over a 3-day period, while efflux occurred more rapidly within a 3-h time period. Four putative genes involved in Zn2+ uptake and efflux in N. punctiforme were identified: (i) the predicted Co/Zn/Cd cation transporter, putative CDF; (ii) the predicted divalent heavy-metal cation transporter, putative Zip; (iii) the ATPase component and Fe/Zn uptake regulation protein, putative Fur; and (iv) an ABC-type Mn/Zn transport system, putative zinc ZnuC, ZnuABC system component. Quantitative real-time PCR indicated the responsiveness of all four genes to 22 µM ZnCl2 within 3 h, followed by a reduction to below basal levels after 24 h by putative ZIP, ZnuC, and Fur and a reduction to below basal level after 72 h by putative CDF efflux gene. These results demonstrate differential regulation of zinc transporters over time, indicating a role for them in zinc homeostasis in N. punctiforme.
History
Journal
Applied and environmental microbiologyVolume
75Issue
3Pagination
784 - 791Publisher
American Society for MicrobiologyLocation
Washington, D.C.Publisher DOI
ISSN
0099-2240eISSN
1098-5336Language
engPublication classification
C1 Refereed article in a scholarly journal; C Journal articleCopyright notice
2009, American Society for MicrobiologyUsage metrics
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