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| Titel |
Effects of copper mineralogy and methanobactin on cell growth and sMMO activity in Methylosinus trichosporium OB3b |
| VerfasserIn |
E. Chi Fru, N. D. Gray, C. McCann, J. de C. Baptista, B. Christgen, H. M. Talbot, A. Ghazouani, C. Dennison, D. W. Graham |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 10 ; Nr. 8, no. 10 (2011-10-14), S.2887-2894 |
| Datensatznummer |
250006160
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| Publikation (Nr.) |
 copernicus.org/bg-8-2887-2011.pdf |
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| Zusammenfassung |
| Controls on in situ methanotroph activity are not well understood. One
potentially important parameter is copper (Cu) because it is the metal-centre
of particulate methane monooxygenase (pMMO), the most active enzyme for
oxidizing methane to methanol. Further, Cu-to-cell ratios influence the
relative expression of pMMO versus the alternate soluble MMO (sMMO) in some
species. However, most methanotroph studies only have assessed readily
soluble forms of Cu (e.g. CuCl2) and there is a dearth of Cu-related
activity data for Cu sources more common in the environment. Here we
quantified sMMO activity (as a practical indicator of Cu availability) and
growth kinetics in Methylosinus trichosporium OB3b, an organism that
expresses both pMMO and sMMO, when grown on Cu-minerals with differing
dissolution equilibria to assess how mineral type and methanobactin (mb)
might influence in situ methanotroph activity. Mb is a molecule produced by
M. trichosporium OB3b that has a high affinity for Cu, reduces Cu
toxicity, and may influence Cu availability in terrestrial systems.
CuCO3.Cu(OH)2 and CuO were chosen for study based on modelling
data, reflecting more and less soluble minerals, respectively, and were found
to affect M. trichosporium OB3b activity differently. Cells grew
without growth lag and with active pMMO on CuCO3.Cu(OH)2,
regardless of the amount of mineral supplied
(<500 μmoles Cu-total l−1). The organism also grew well on
CuO; however, significant sMMO activity was retained up to
50 μmoles Cu-total l−1, although sMMO activity was
suppressed by supplemental mb and-or direct cell-mineral contact. Mb addition
increased growth rates (p < 0.05) with both minerals. Results show mb
broadly stimulates growth, but Cu mineralogy and mb dictate whether sMMO or
pMMO is active in the cells. This explains why sMMO activity has been seen in
soils with high Cu and also has implications for predicting dominant MMO
activity in terrestrial bioremediation applications. |
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