. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. WATER MITE PHOTOBEHAVIOR 167 0) in c o CL in o> 60 50- 40- 30- I 20- 10-. 10 14 18 22 26 30 Mantle homogenate (jjg protein/ml APW) FIGURE 1. Dose-response relationships of the negative phototaxis of Unionicola formosa induced by mantle homogenate of Anodonta imbecilis. Data points are the X ± SE (N = 90). All concentrations of mantle homogenate ^ ^g protein/ml elicited negative phototactic responses that were not different from each other (ANOVA, P > ) but that all were significantly greater than t
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. WATER MITE PHOTOBEHAVIOR 167 0) in c o CL in o> 60 50- 40- 30- I 20- 10-. 10 14 18 22 26 30 Mantle homogenate (jjg protein/ml APW) FIGURE 1. Dose-response relationships of the negative phototaxis of Unionicola formosa induced by mantle homogenate of Anodonta imbecilis. Data points are the X ± SE (N = 90). All concentrations of mantle homogenate ^ ^g protein/ml elicited negative phototactic responses that were not different from each other (ANOVA, P > ) but that all were significantly greater than the responses to lower concentrations (ANOVA; SNK; P 104 daltons) of ultrafiltered MH elicited negative phototaxis (Table I). The magnitude of the negative response induced by this fraction was significantly higher (P < , t test) than that elicited by unmodified homogenate. Heating MH at 80°C and at 100°C for 30 minutes destroyed its capacity to induce negative phototaxis (Table I). Although heating MH at 60°C for 30 min resulted in a significant reduction in the negative response (and a concomitant increase in positive phototaxis), the potential of MH to induce negative phototaxis was not completely eliminated by this milder heat treatment (Table I). Trypsinization of MH resulted in a significant reduction of the magnitude of negative phototaxis and restored the level of positive phototaxis to about 60% of that which occurs in plain APW (Table I). Exposure of mites to trypsin in the absence of MH had no significant effect on their positive phototaxis. In addition, the incubation of U. formosa for 1 h in a 1000-fold higher concentration of trypsin than that to which they were exposed in the trypsinization assay did not significantly affect their subsequent photonegative behavior in the presence of unaltered MH (Table I). DISCUSSION Chemical influences on the sign of an organism's phototaxis are not unknown. Thorson (1964) showed that a reduced salinity could reverse t
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
