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Journal Articles Environmental Science and Pollution Research Year : 2015

Dynamic of bacterial communities attached to lightened phytodetritus

Morgan Petit
  • Function : Author
CE
Remi Amiraux
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CE
Sophie Guasco
MEB
Joshua Armitano
  • Function : Author
Cécile Jourlin-Castelli
  • Function : Author
Vincent Méjean
  • Function : Author

Abstract

The effects of singlet oxygen ((1)O2) transfer to bacteria attached on phytodetritus were investigated under laboratory-controlled conditions. For this purpose, a nonaxenic culture of Emiliania huxleyi in late stationary phase was studied for bacterial viability. Our results indicated that only 9 ± 3 % of attached bacteria were alive compared to 46 ± 23 % for free bacteria in the E. huxleyi culture. Apparently, under conditions of low irradiance (36 W m(-2)), during the culture, the cumulative dose received (22,000 kJ m(-2)) was sufficiently important to induce an efficient (1)O2 transfer to attached bacteria during the senescence of E. huxleyi cells. At this stage, attached bacteria appeared to be dominated by pigmented bacteria (Maribacter, Roseobacter, Roseovarius), which should resist to (1)O2 stress probably due to their high contents of carotenoids. After subsequent irradiation of the culture until fully photodegradation of chlorophyll, DGGE analyses showed that the diversity of bacteria attached to E. huxleyi cells is modified by light. Photooxidative alterations of bacteria were confirmed by the increasing amounts of cis-vaccenic photoproducts (bacterial marker) per bacteria observed during irradiation time. Interestingly, preliminary chemotaxis experiments showed that Shewanella oneidensis considered here as a model of motile bacteria was attracted by phytodetritus producing or not (1)O2. This lack of repulsive effects could explain the high mortality rate of bacteria measured on E. huxleyi cells.
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Dates and versions

hal-01201708 , version 1 (17-09-2015)

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Morgan Petit, Patricia Bonin, Remi Amiraux, Valerie Michotey, Sophie Guasco, et al.. Dynamic of bacterial communities attached to lightened phytodetritus. Environmental Science and Pollution Research, 2015, 22 (18), pp.13681-92. ⟨10.1007/s11356-015-4209-0⟩. ⟨hal-01201708⟩
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