. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 0 40 80 120 160 200 20 40 60 80 9H § 6J O CL 3- 6- 3- 40 80 120 160 200 Time (s) o-. 0 20 40 60 80 100 120 Time (s) Figure 7. Examples of electrically induced bioluminescence of Py- rimtmella verticillata. Fifty-volt, 5-ms duration pulses were applied to the medium. (A) Single stimulus delivered at 80s, 120s, and 165 s; each produced a simple response. (B) Stimuli delivered at 1 Hz for 60 s. starting at time = 0, showing temporal summation. (C) Constant 5 Hz stimu- lation, yielding a regular (lashing pattern, perhaps due to
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 0 40 80 120 160 200 20 40 60 80 9H § 6J O CL 3- 6- 3- 40 80 120 160 200 Time (s) o-. 0 20 40 60 80 100 120 Time (s) Figure 7. Examples of electrically induced bioluminescence of Py- rimtmella verticillata. Fifty-volt, 5-ms duration pulses were applied to the medium. (A) Single stimulus delivered at 80s, 120s, and 165 s; each produced a simple response. (B) Stimuli delivered at 1 Hz for 60 s. starting at time = 0, showing temporal summation. (C) Constant 5 Hz stimu- lation, yielding a regular (lashing pattern, perhaps due to an 1 X-s refractory period characteristic of the zooids. (D) Constant 10 Hz stimulation, elic- iting light at a similar initial rate to (C). but without a regular flashing pattern. by the serial excitation of zooids, the colony propagation velocity, taking into account the response delay and the distance between zooids, would be mm • s~'. This value is remarkably similar to the observed saltatory propagation rate of mm • s ' found in this study of mature colonies. Mackie and Bone also found no nerves or gap junctions associated with the light organ, and deemed it unlikely that conducting epithelia could prop- agate this activity, because the normal rate of epithelial conduction in tunicates is about 20 cm • s*1. In addition, no specific cellular depolarizations were associated with Hashing, and the mantle epithelium, to which the light organ is attached, is not a conducting type in the taxon- omically similar ascidians. Luminescent waves typically propagate in the colonial coelenterate Renilla at 6-10 cm-s ' (Nicol, 1955: Morin and Cooke, 1971), and 20- 50 cm • s 'in hydrozoa (Widder et 1989). These high propagation rates are enabled by the underlying nervous tissue. These data indicate that the luminous wave is propagated by a photic chain reaction. The mechanism underlying the saltatory conduction of luminescence may derive in part from the diffe
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
