Anoxygenic phototrophic bacteria in eutrophic coastal lagoons of the French Mediterranean and Atlantic Coasts (Prévost Lagoon, Arcachon Bay, Certes fishponds)

Guyoneaud, Rémy; Matheron, Robert; Baulaigue, Renée; Podeur, K.; Hirschler, A; Cartigny, Pierre

doi:10.1007/978-94-009-1744-6_3

Cited by 14 publications

(23 citation statements)

References 21 publications

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“…Prosthecochloris aestuarii strain CE2404 was isolated at the Arcachon Laboratory of Oceanography from the sediment of a shallow brackish lagoon (Certes fishponds, France) by using standard agar dilution series in seawater medium (Guyoneaud et al 1996). For all experiments, strain CE2404 was grown in standard mineral medium (Pfennig and Trüper 1989) supplemented with sodium chloride (2%), sodium sulfide (3 mM), and sodium acetate (1 mM).…”

Section: Methodsmentioning

confidence: 99%

Light responses in the green sulfur bacterium Prosthecochloris aestuarii : changes in prosthecae length, ultrastructure, and antenna pigment composition

Guyoneaud

Borrego

Martínez-Planells

et al. 2001

Archives of Microbiology

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The morphology (mainly prosthecae length), ultrastructure, and antenna pigment composition of the green sulfur bacterium Prosthecochloris aestuarii changed when grown under different light intensities. At light intensities of 0.5 and 5 micromol quanta m(-2) s(-1), the cells had a star-like morphology. Prosthecae, the characteristic appendages of the genus Prosthecochloris, were 232 nm and 194 nm long, respectively. In contrast, when grown at 100 micromol quanta m(-2) s(-1), these appendages were shorter (98 nm) and the cells appeared more rod-shaped. Transmission electron microscopy revealed a significant decrease in the cell perimeter to area ratio and in the number of chlorosomes per linear microm of membrane as light intensity increased. In addition to these morphological and ultrastructural responses, Prosthecochloris aestuarii exhibited changes in its pigment composition as a function of light regime. Lower specific pigment content and synthesis rates were found in cultures grown at light intensities above 5 micromol quanta m(-2) s(-1). A blue shift in the bacteriochlorophyll (BChl) c Q(y) absorption maximum of up to 17.5 nm was observed under saturating light conditions (100 micromol quanta m(-2) s(-1)). This displacement was accompanied by changes in the composition of BChl c homologs and by a very low carotenoid content. The morphological, ultrastructural and functional changes exhibited by Prosthecochloris aestuarii revealed the strong light-response capacity of this bacterium to both high and low photon-flux densities.

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Section: Methodsmentioning

confidence: 99%

Light responses in the green sulfur bacterium Prosthecochloris aestuarii : changes in prosthecae length, ultrastructure, and antenna pigment composition

Guyoneaud

Borrego

Martínez-Planells

et al. 2001

Archives of Microbiology

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“…Mercury methylation/ demethylation experiments were carried out in an optimal synthetic medium at pH 7.2. The optimal synthetic medium was prepared according to [17] and contained (in g/L unless 1]) was distributed in sterile 30 ml penicillin flasks, sealed with PTFE-coated butyl rubber stoppers, and flushed with N 2 /CO 2 gas mixture (9/1) to maintain strict anaerobic conditions. For each bacterial strain studied, the medium was inoculated at 10% (v/v) of the final volume (30 ml), with precultures in the exponential growth phase, and spiked with 7 mg/L 199 Hg(II) and 1 mg/L Me 201 Hg.…”

Section: Mercury Methylation and Demethylation Experimentsmentioning

confidence: 99%

Simultaneous determination of mercury methylation and demethylation capacities of various sulfate‐reducing bacteria using species‐specific isotopic tracers

Bridou

Monperrus

González

et al. 2010

Enviro Toxic and Chemistry

109

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The use of species-specific isotopic tracers for inorganic and methyl mercury has allowed the simultaneous determination of the methylation and demethylation potentials of pure culture of isolated sulfate-reducing (SR) bacterial strains using low Hg species concentration levels (7 µg/L (199)Hg(II), 1 µg/L Me(201)Hg). A major advantage of the method reported here is that it can be used to follow simultaneously both the degradation of the species added but also the formation of their degradation products and thus the determination during the same incubation of the specific methylation/demethylation yields and rate constants. Methylation/demethylation capacities and extents have been found to differ between the tested strains and the tested conditions. The methylating/demethylating capacities of bacteria appear to be strain specific. All the methylating strains were found to demethylate methylmercury (MeHg). The active mechanism responsible for Hg methylation appears directly dependent on the bacterial activity but is not dependent on the metabolism used by the tested bacteria (sulfate reduction, fermentation, or nitrate respiration). The results provide confirmation that SR strains contribute to MeHg demethylation under anoxic conditions, leading to Hg(II) as the end product, consistent with the oxidative degradation pathway. Kinetic experiments have allowed specific transformation rate constants to be addressed for the two reversible processes and the reactivity of each isotopic tracer to be compared. The differential reactivity highlighted the different steps involved in the two apparent processes (i.e., uptake plus internal transformation of mercury species). Methylation appears as the slowest process, mainly controlled by the assimilation of Hg(II), whereas demethylation is faster and not dependent on the MeHg concentration.

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“…The purple sulfur bacteria tested, Chromatium gracile strain CE2201, isolated from the fish ponds sediments (Guyoneaud et al ., 1996), was originating from the culture collection of the laboratory. It was cultivated in the Pfennig & Triiper (1981) medium with 5 mM of acetate and 5 mM of thiosulphate at pH=7 and salinity = 30%o .…”

Section: Bacterial Culturementioning

confidence: 99%

“…(1980) and Schiemer (1982) found that growth of two nematode species fed on Escherichia coli could be effective with at least bacterial concentrations of about 10 8 cells ml -1 , this higher bacterial concentration can be explained once again by the small size of E. coli cells . The phototrophic 87 bacterial densities in the sediments of the fish ponds of Certes were higher than 107 cells ml -1 during the three sampling periods (March, June and September 1993) (Guyoneaud et al ., 1996) . Caumette (1986) observed phototrophic bacteria densities of 10 7 cells ml -1 in the sediment of Prevost Lagoon during the summer and in the water column the densities attained 108 cells ml -1 during `red waters' .…”

Section: Michaelis-mentenmentioning

confidence: 99%

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The role of phototrophic sulfur bacteria as food for meiobenthic harpacticoid copepods inhabiting eutrophic coastal lagoons

1996

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Laboratory experiments were undertaken using Amonardia normani and Schizopera cf compacta, two meiobenthic harpacticoid copepods commonly found in coastal lagoons . The first experiments were designed to determine if the phototrophic sulfur bacteria Chromatium gracile can be ingested by these copepods and at what concentrations . Egestion rate was used as an index of feeding rate. The response of the egestion rate, expressed in numbers of faecal pellets produced by copepod per day, as a function of bacterial concentration followed the functional model . A . normani attained constant feeding rates from the bacterial concentration of 1 x 107 cells ml -1 (5 jig C ml -1 ) onwards, S. cf. compacta attained constant feeding rates from 2 .6 x 107 cells ml -1 (13 pg C ml -1 ) onwards. The faecal pellet volume changed significantly (p<0 .05) between food concentrations for A . normani but not for S. cf. compacta (p>0.05) . In order to investigate the effect of the phototrophic bacterial diet on the population dynamics of A . normani three groups of nauplii were maintained at 2 x 107 cells ml -1 and observed every day. The mortality of these nauplii was very high compared to those maintained on a diatom diet (Nitzschia constricta) ; only in one of the groups did some copepodites develop but no adults were ever observed. Adults fed on bacteria did not have different (p>0.05) survival rates compared to those fed on diatoms, nevertheless, the number of nauplii produced was significantly less (p<0 .05) on the bacterial diet. These results lead us to suggest that although the phototrophic sulfur bacteria (Chromatium gracile) can be ingested by both copepod species it cannot sustain the full development of the A. normani population . Thus, a bloom of phototrophic sulfur bacteria does not seem to be a favourable situation for opportunistic benthic copepods to colonize eutrophic coastal lagoons after a dystrophic crisis .

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Anoxygenic phototrophic bacteria in eutrophic coastal lagoons of the French Mediterranean and Atlantic Coasts (Prévost Lagoon, Arcachon Bay, Certes fishponds)

Cited by 14 publications

References 21 publications

Light responses in the green sulfur bacterium Prosthecochloris aestuarii : changes in prosthecae length, ultrastructure, and antenna pigment composition

Light responses in the green sulfur bacterium Prosthecochloris aestuarii : changes in prosthecae length, ultrastructure, and antenna pigment composition

Simultaneous determination of mercury methylation and demethylation capacities of various sulfate‐reducing bacteria using species‐specific isotopic tracers

The role of phototrophic sulfur bacteria as food for meiobenthic harpacticoid copepods inhabiting eutrophic coastal lagoons

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