. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 480 BASSOT ET AL. or, more often, to a suction electrode attached to the surface of the animal or resting gently against it. Experimental operations on the nectophores included surgical interventions such as ablation of the nerve ring, immobilization of a dissected piece of tissue held to the Sylgard base with very fine cactus spines, and cutting of parts of the nectophore. Fragments of nectophores were fixed for electron microscopy in 6% glutaraldehyde in a M cacodylate buffer pH , embedded in epon, cut with a LKB mi
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 480 BASSOT ET AL. or, more often, to a suction electrode attached to the surface of the animal or resting gently against it. Experimental operations on the nectophores included surgical interventions such as ablation of the nerve ring, immobilization of a dissected piece of tissue held to the Sylgard base with very fine cactus spines, and cutting of parts of the nectophore. Fragments of nectophores were fixed for electron microscopy in 6% glutaraldehyde in a M cacodylate buffer pH , embedded in epon, cut with a LKB microtome and observed with a Philips EM 300 microscope. RESULTS Spontaneous events Isolated nectophores remain capable of all the behavioral activities described in the colony. Usually, a nectophore which has been detached from the colony and immobilized in the observation chamber is opalescent (blanching having occurred during manipulations) and completely motionless. After 10 to 20 min, transparency is recovered again, except at the spots where pins have pierced the epithelium; the prongs and the horns are the last to lose their opacity. The first "spontaneous" movement to be observed is an involution of the margin, followed by a slow relaxation. Then, other involutions may occur. Independently, isolated flashes or short flickering series of flashes are emitted (Fig. 4), again without any external stimulation. Combined records show blanching occuring together with each luminous event. A period of quietness follows, which usually lasts 10 to 20 min. Then swimming begins, in bursts of rhythmic activity alternating with periods of rest of 10 to 30 sec. The duration of swimming bouts steadily increases. The beating rhythm is very regular, about 4/sec at 20° C (Fig. 5). Our actographic technique, which measures changes in the diffraction pattern of the laser beam, has an extreme sensitivity towards minute displacements, but the shape and the amplitude of the curves are n
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
