. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LUMINESCENCE CONTROL IN CHAETOPTERUS 589 100ms _i 60MV 2S. 200ms FIGURE 6. Recordings of electrical activity in the nerve cord (upper trace) in response to mechanical stimulation (.015 dyne) of the parapodial epidermis from the corresponding posterior segment (lower trace). Note the increment of impulse amplitude as a function of stimulus duration. Similar responses were obtained in all three specimens tested. was dependent on stimulus strength or duration, was of much shorter duration than those associated with propagated l
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LUMINESCENCE CONTROL IN CHAETOPTERUS 589 100ms _i 60MV 2S. 200ms FIGURE 6. Recordings of electrical activity in the nerve cord (upper trace) in response to mechanical stimulation (.015 dyne) of the parapodial epidermis from the corresponding posterior segment (lower trace). Note the increment of impulse amplitude as a function of stimulus duration. Similar responses were obtained in all three specimens tested. was dependent on stimulus strength or duration, was of much shorter duration than those associated with propagated luminescent responses (Fig. 5). The photogenic gland appears as a swollen mass, 2-3 mm in diameter, and yellowish in live, sexually mature animals. It extends dorso-medially from the 10th segment to the intersection of the lateral and longitudinal ciliated grooves in the 12th segment (Fig. 2). Observations on serial histological sections from formalin-fixed, paraffin-embedded glands, stained with Mallory's triple stain, revealed that the gland consists of local enlargements of the glandular epithelium filled with mucous cells in a layer 700-800 nm deep at the expense of other cell types such as supportive and myoepithelial cells (Anctil, 1979). The photogenic gland, which was unresponsive to electrical stimulation either of the notopodial surface or of the nerve cord (Figs. 2, 3), consistently responded to direct mechanical handling by the release of a large quantity of brightly luminescent mucus in the water. The type of stimulation necessary to produce such a response (pinching or application of pressure on the gland) caused a rupture of the overlying epithelium of these glands, as visualized through a dissecting microscope. Thus epithelial rupture was an apparent prerequisite for expulsion of the mucus. In order to assess the significance of mechanical disturbances in the context of tube-dwelling, eight tubes with their resident worm still inside were subjected to mechanical
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
