CO2fixation in tissues of marine oligochaetes (Phallodrilus leukodermatusandP. planus) containing symbiotic, chemoautotrophic bacteria
✍ Scribed by H. Felbeck; G. Liebezeit; R. Dawson; O. Giere
- Publisher
- Springer-Verlag
- Year
- 1983
- Tongue
- English
- Weight
- 582 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0025-3162
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✦ Synopsis
The gutless marine oligochaetes Phallodrilus leukodermatus and P. planus are known to contain bacteria in their tissues. In this study, we demonstrate that these worms, collected and studied 1982 in Bermuda, contain enzymes characteristic for chemoautotrophic bacteria, as has previously been shown for pogonophorans and some bivalve molluscs. The enzymes are ribulose-l,5-diphosphate carboxylase (RuBPCase), ATP-sulfurylase, sulfite oxidase and nitrate reductase. Adenosinephosphosulfate reductase and rhodanese could not be detected. In addition, P. leukodermatus was tested for the ability to take up and metabolize radiolabeled bicarbonate and glucose from the surrounding seawater. During incubation periods of up to 6h, most of the radioactivity administered as bicarbonate was found in malate and succinate; sugars and sugar phosphates were heavily labeled only after short incubation periods of up to 30 rain. In comparison to bicarbonate, glucose was taken up from the medium slowly. The quantitative importance of the fixation of bicarbonate versus uptake of dissolved organic matter for the worms' metabolic needs are discussed.