Browsing by Author "Prieur, D."

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Microscopic examination and fatty acid characterization of filamentous bacteria colonizing substrata around subtidal hydrothermal vents
(1989-06) Jacq, E.; Prieur, D.; Nichols, P. D.; White, D. C.; Porter, T.; Geesey, Gill G.
Microscopic examination of the whitish mat that covered the substrata around subtidal hydrothermal vents at White Point in southern California revealed a “Thiothrix-like” bacterium containing sulfur inclusions as the dominant filamentous form in this microbial community. The matlike appearance developed as a result of the closely-packed manner inwhich the basal ends of the filaments were anchored to the substrate. The dominant phospholipid fatty acids of these filaments (16:0, 16:1w7c, 18:0, 18:1w7c) were similar to those recovered from a sample of Beggiatoa isolated from a spring in Florida. Filaments from both sources contained small quantities of C18 and C20 polyunsaturated fatty acids, as well. A larger but less abundant sheathless, filamentous form, which also contained sulfur inclusions and displayed a cell wall structure similar to a previously described Thioploca strain, also colonized the substrata around the subtidal mat. The preservation methods used in the preparation of thin-sections of the subtidal mat material were found to be inadequate for defining some key cellular structures of the large filaments. Nevertheless, the results demonstrate that the filamentous bacteria comprising the microbial mat in the vicinity of the subtidal vents exhibit some of the features of the free-living filamentous microorganisms found in deep-water hydrothermal areas.
Seasonal Variations in Bacterial Colonization of Stainless Steel, Aluminum and Polycarbonate Surfaces in a Seawater Flow System
(1989-03) Fera, P.; Siebel, M. A.; Characklis, William G.; Prieur, D.
Before the construction of an Ocean Thermal Energy Conversion (OTEC) power plant, an experimental station was built near the entrance of the Bay of Brest (France) in order to perform preliminary studies. Bacterial colonisation of three substrata (stainless steel UB6, aluminium AG4 and polycarbonate filters) was observed in a continuous flow seawater system. The study was performed between May 1983 and May 1984 and included seven experiments of 15 days each. The early events in bacterial colonisation of these materials may be affected by both water quality and type of substratum. If these two parameters influence the adsorption step of the biological process (0 to 1 h), seasonal variation in water quality seems to be more important during the accumulation step (1 h to 6 days), because of its effect on bacterial metabolism.