. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. (b) |imol oxygen g-1 h-' ol suKjide g-1 tr1 100 200 300 400 Time(min) 500 600 Figure 2. Plot of inorganic carbon (a) and sulfide and oxygen flux rates (b) in Riftia pachyptila. Each point represents the values measured at the time indicated (the entire trace represents results from one animal). Water conditions of ± mmol I"' SCO,, ± mmol I"' SH,S, ± mmol l~' O2. and pH of ± were maintained. In plot 2a. acquisition refers to a net uptake of inorganic carbon, and production ref
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. (b) |imol oxygen g-1 h-' ol suKjide g-1 tr1 100 200 300 400 Time(min) 500 600 Figure 2. Plot of inorganic carbon (a) and sulfide and oxygen flux rates (b) in Riftia pachyptila. Each point represents the values measured at the time indicated (the entire trace represents results from one animal). Water conditions of ± mmol I"' SCO,, ± mmol I"' SH,S, ± mmol l~' O2. and pH of ± were maintained. In plot 2a. acquisition refers to a net uptake of inorganic carbon, and production refers to a net elimination of inorganic carbon. When the worm demonstrated net acquisition of inorganic carbon (dutotrophy), ethoxyzolamide, an inhibitor of carbonic anhydrase. was added to the aquaria (2 mmol 1" ', arrow). decreased rate of coelomic fluid SCO2 uptake, and a com- plete shutdown in the movement of SCO2 into vascular blood. The inhibition of CA by EZ, and the subsequent effect on carbon acquisition rates, demonstrates the impor- tance of CA in maintaining an efficient net influx of inor- ganic carbon. It is interesting that the inhibition of CA by EZ resulted in net rates of CO-, production that are similar to the pre-autolrophic rates of CO-, production. In these experiments, freshly captured worms typically do not ex- hibit net inorganic carbon acquisition for the first 20 h. Thus, the net production of CO2 during the first few hours represents CO2 production from both host and symbiont respiration. CO2 resulting >m the metabolic processes within the association is, mosi likely, insufficient to meet the carbon need of the bacteria. Therefore, the acquisition of C; from the environment is employed to help fulfill this demand, and we see this as a rather large net uptake of CO^. Inhibition of CA results in similar rates of COo production, indicating a nearly complete disruption of the carbon-con- centrating system. Until recently, it was thought that EZ
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
