Chemolithoheterotrophy in a metazoan tissue: thiosulfate production matches ATP demand in ciliated mussel gills
Jeannette E. Doeller1,*,
Manfred K. Grieshaber2 and
David W. Kraus1
1 Department of Biology, University of Alabama at Birmingham, 1300 University Boulevard, Birmingham, AL 35294-1170, USA and
2 Institut für Zoophysiologie, Heinrich-Heine-Universität, Universitätsstraße 1, 40225 Düsseldorf, Germany
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Fig. 1. Thiol levels in Geukensia demissa gills as a function of time. Gills were exposed to 100 µmol l-1 Na2S at time zero. Thiols pertaining to the left y-axis are thiosulfate (filled circles), glutathione (filled diamonds) and cysteine (filled upright triangles), connected with solid lines. Thiols pertaining to the right y-axis are sulfide (filled squares) and sulfite (filled inverted triangles), connected with broken lines. Lines serve only to connect data points. Open symbols shown near the 50 min mark depict levels of the same thiols measured in control tissue after 50 min. Values are means ± S.D. (N=6). To eliminate overlap of error bars, some points have been offset by 0.25–0.5 min. Asterisks designate a significant difference from the value at 0 min (Bonferroni test). (A) Gills exposed to 0.5 µmol l-1 5-HT. (B) Gills exposed to 10 µmol l-1 5-HT.
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Fig. 2. The kinetics of thiosulfate production and release in Geukensia demissa gills. Gills were exposed to 100 µmol l-1 Na2S at time zero. Thiols pertaining to the left y-axis are thiosulfate measured in tissue (circles) and thiosulfate measured in the ambient sea water (squares), connected with solid lines. The thiol pertaining to the right y-axis is sulfide in the sea water (upright triangles), connected with a broken line. Lines serve only to connect data points. Values are means ± S.D., shown as upper or lower error bars to reduce overlap (N=6). (A) Gills exposed to 0.5 µmol l-1 5-HT. (B) Gills exposed to 10 µmol l-1 5-HT.
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Fig. 3. Thiol levels in Geukensia demissa gills (black columns) and Mytilus edulis gills (grey columns). Gills were exposed to 100 µmol l-1 Na2S at time zero for 10 min. Thiols pertaining to the left y-axis are cysteine (CYS), glutathione (GLU) and thiosulfate (THIO). Thiols pertaining to the right y-axis are sulfite (ST) and sulfide (SD). Values are means ± S.D. (N=3–6). Asterisks designate significant difference between mussel species (paired t-test). (A) Gills exposed to 0.5 µmol l-1 5-HT. (B) Gills exposed to 10 µmol l-1 5-HT.
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Fig. 4. Rates of oxygen consumption (grey columns) and sulfide oxidation (black columns) in mussel gills exposed to the low and high concentration of 5-HT. Numbers over each pair of columns refer to the oxygen/sulfide ratio for that measurement pair. Values are means ± S.D. (N=3–4). Asterisks designate significant difference between low- and high-5-HT treatments; double daggers designate significant difference between mussel species (Bonferroni test). (A) Geukensia demissa gills. (B) Mytilus edulis gills.
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Fig. 5. Thiol levels in Geukensia demissa gills as a function of Na2S concentration. Thiols pertaining to the left y-axis are thiosulfate (circles), glutathione (diamonds) and cysteine (upright triangles), connected with solid lines. Thiols pertaining to the right y-axis are sulfide (squares) and sulfite (inverted triangles), connected with broken lines. Lines serve only to connect data points. Values are means ± S.D. (N=3). To eliminate overlap of error bars, some points have been offset by 10 µmol l-1. Asterisks designate significant difference from the value at 0 µmol l-1 Na2S (Bonferroni test). (A) Gills exposed to 0.5 µmol l-1 5-HT. (B) Gills exposed to 10 µmol l-1 5-HT.
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Fig. 6. Thiol levels in Mytilus edulis gills as a function of Na2S concentration. Thiols pertaining to the left y-axis are thiosulfate (circles), glutathione (diamonds) and cysteine (upright triangles), connected with solid lines. Thiols pertaining to the right y-axis are sulfide (squares) and sulfite (inverted triangles), connected with broken lines. Lines serve only to connect data points. Values, except for glutathione, are means ± S.D. (N=3). Glutathione values are only the mean; standard deviations reach 71–99 % of the mean in gills exposed to any level of Na2S and are therefore not included. To eliminate overlap of error bars, some points have been offset by 2 µmol l-1. Asterisks designate a significant difference from the value at 0 µmol l-1 Na2S (Bonferroni test). (A) Gills exposed to 0.5 µmol l-1 5-HT. (B) Gills exposed to 10 µmol l-1 5-HT.
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Fig. 7. Oxygen/sulfide ratio in Geukensia demissa gills (circles) and Mytilus edulis gills (squares) as a function of Na2S concentration. Gills were exposed to 0.5 µmol l-1 5-HT (open symbols) or 10 µmol l-1 5-HT (filled symbols). Values are means ± S.D. (N=3). To eliminate overlap of error bars, some points have been offset by 10 µmol l-1. Lines serve only to connnect data points.
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Fig. 8. Succinate levels in Geukensia demissa gills (filled columns) and Mytilus edulis gills (hatched columns) under aerated conditions (Air), aerated conditions with 100 µmol l-1 Na2S added at time zero (Air+Na2S) and anaerobic conditions produced by nitrogen gas (N2), all for 10 min. Values are means ± S.D. (N=3). Asterisks designate a significant difference from the value under aerated conditions; double daggers designate a significant difference from the value under aerated conditions with 100 µmol l-1 Na2S. (A) Gills exposed to 0.5 µmol l-1 5-HT. (B) Gills exposed to 10 µmol l-1 5-HT.
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© The Company of Biologists Ltd 2001
