. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 422 R. L. MILLER AND K. R. KING. FIGURE 2. Paths ofOikopleura dioica sperm in the presence of a pipette injecting sea water. Curved trails with rare, random loops. Pipette diameter is 30 random turns in the form of sharp loops may occur in some trails within 4-5 frames (approximately s) (Fig. 2). The direction taken after these loops have been completed is roughly 270° relative to the original path direction. The form of the new path is the same as the original. Injection of sea water into the sperm suspension produces
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 422 R. L. MILLER AND K. R. KING. FIGURE 2. Paths ofOikopleura dioica sperm in the presence of a pipette injecting sea water. Curved trails with rare, random loops. Pipette diameter is 30 random turns in the form of sharp loops may occur in some trails within 4-5 frames (approximately s) (Fig. 2). The direction taken after these loops have been completed is roughly 270° relative to the original path direction. The form of the new path is the same as the original. Injection of sea water into the sperm suspension produces no change in sperm motility or direction as long as the rate of injection is slow enough to prevent physical shifting of the sperm. If a sea water solution ofOikopleura egg extract is injected (experimental trails), the sperm behave quite differently (Fig. 3). Sperm enter the field on a typical preat- traction circular path at about average velocity ( /um/s; Table I) but, about 130 nm away from the pipette tip, undergo a looping behavior which brings them closer to the pipette tip. The average velocity during these trails is (Table I). TABLE I Average velocities along Oikopleura sperm trails before and during chemotaxis Number Number of Mean Trail type of trails measurements (M/S) SD SE P Control trails 21 852 +.065 ) Experimental trails 11 681 ±.096 j <.001 Pre-attraction 148 +.129 ) Post-attraction 148 ±.136 j Control and Experimental trails refer to groups of trails in sea water and exposed to a gradient of sperm attractant, respectively. Pre-attraction and Post-attraction refers to measurements made at the start of the 11 experimental trails and the same number of measurements made at the end of the same set of trails, respectively. a, Mest, groups; control trails versus experimental trails. b, /-test, pairs; pre-attraction versus post-attraction in experimental Please note that these images are
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