. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. AMINO ACID TRANSPORT IN WORMS 439 both cases, determinations of fluorescence begin to diverge from determinations of radioactivity after two hours. In both cases, radioactivity does not continue to decline indefinitely. This does not represent a limitation of the transport system since 14C-glycine at concentrations of 2 to 4 X 1O7 M is removed exponentially by both species. Figure 3 presents data for two individuals of Parcitrythoc in which influx and net influx of glycine was measured in the flow system. Error bars represen
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. AMINO ACID TRANSPORT IN WORMS 439 both cases, determinations of fluorescence begin to diverge from determinations of radioactivity after two hours. In both cases, radioactivity does not continue to decline indefinitely. This does not represent a limitation of the transport system since 14C-glycine at concentrations of 2 to 4 X 1O7 M is removed exponentially by both species. Figure 3 presents data for two individuals of Parcitrythoc in which influx and net influx of glycine was measured in the flow system. Error bars represent tl standard deviation of the average difference of seven determinations of radio- activity or fluorescence at inflow and outflow ports. Actual differences range from to 7c/o of inflow. Since P_. w7as measured at the inflow, the values are systematic overestimates of the average PO2 experienced by the animal during the observation period. Six such experiments \vere performed. In all cases there was a sustained high rate of influx, essentially comparable to that observed in aerobic depletion experiments, until ambient Po2 was reduced to approximately 10% to 2Q% of air saturation values. In some cases, there was some decrease with decreasing P02 prior to the more conspicuous decrease observed at very low Po2- The data are too variable to justify mathematical treatment but suffice to demon- strate that influx and net influx are not linearly related to P02 over this range of oxygen concentrations. In these observations, influx and net influx of glycine were inhibited to a greater extent under anoxic conditions than the inhibition. t 20 40 60 80 100 FIGURE 3. Effect of P02 on influx and net influx of glycine into Parcurythoc. Circles and squares represent separate experiments on two individual worms. Closed symbols represent influx of 14C-glycine; open symbols represent net influx of total primary amines. Bars are ± 1 ; those cases in which open symbols have no error bars
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
