. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DISINTEGRATION OF HYDRA NEMATOCYSTS 395 (xlO5) 25 2 T) £ o \ o 20 15 I. 25 50 75 100 125 Duration of PG treatment 150 175 ( h ) FIGURE 2. Time course of PG effects on desmonemes in a whole hydra. (O, control; D, mA/; A, mA/; X, mA/) treatment. The proportions of each cell type were also little different from those in the untreated hydras. Effect of PG on hydras in which the supply of desmonemes was blocked by cutting In normal hydra, the number of nematocytes is kept nearly constant by balanced production and dep
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DISINTEGRATION OF HYDRA NEMATOCYSTS 395 (xlO5) 25 2 T) £ o \ o 20 15 I. 25 50 75 100 125 Duration of PG treatment 150 175 ( h ) FIGURE 2. Time course of PG effects on desmonemes in a whole hydra. (O, control; D, mA/; A, mA/; X, mA/) treatment. The proportions of each cell type were also little different from those in the untreated hydras. Effect of PG on hydras in which the supply of desmonemes was blocked by cutting In normal hydra, the number of nematocytes is kept nearly constant by balanced production and depletion (Bode and Flick, 1976). The decrease of the desmonemes in PG-treated hydra could be caused by inhibition of production, or acceleration of depletion, or both. Nematoblast cells differentiating to desmonemes are located in the gastric region, and absent just under the hypostome and in the tentacles (David and Challoner, 1974). Thus, the supply of newly matured desmonemes to the tentacles can be stopped for at least 60 h by removing the hydra's body just under the hypostome. The interstitial cells remaining in the hypostome might start to differentiate into desmonemes just after cutting, but it should take more than 60 h for differentiation from the final cell division to the matured nematocyte (David and Gierer, 1974). Hydras were divided into two groups, I and II. Group I consisted of intact hydra while group II consisted of tentacles and hypostome only. Half of the animals of each group were incubated in PG (these were designated as PG-I and PG-II). The tentacles of group II animals (Control-II and PG-II) were not supplied with new desmonemes, while those of group I (Control-I and PG-I) were supplied during. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Ma
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
