. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 258 Y. K. MARUYAMA 100i BO- Vo fvt. 20 FRACTION NO. FIGURE 4. Gel-filtration of radial nerve extracts from H. leucospilota. Two or three ml of RNE (100 mg per 1 ml of sea water) were placed in Sephadex G-15 columns ( X 42 cm) and Sephadex G- 50 columns ( X 42 cm), respectively. Sea water (pH ) was used as eluant (30 ml/h), and fraction size was 5 ml. Each fraction was assayed with an ovarian fragment, and the GVBD rate was obtained from all the oocytes of the fragment. The elution pattern was simultaneously moni
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 258 Y. K. MARUYAMA 100i BO- Vo fvt. 20 FRACTION NO. FIGURE 4. Gel-filtration of radial nerve extracts from H. leucospilota. Two or three ml of RNE (100 mg per 1 ml of sea water) were placed in Sephadex G-15 columns ( X 42 cm) and Sephadex G- 50 columns ( X 42 cm), respectively. Sea water (pH ) was used as eluant (30 ml/h), and fraction size was 5 ml. Each fraction was assayed with an ovarian fragment, and the GVBD rate was obtained from all the oocytes of the fragment. The elution pattern was simultaneously monitored with 280 nm absorption, and its elution pattern through the G-50 column was shown in a curved-line. The scale of 280 nm absorption is shown in the ordinate at the right side of the figure. Vo, void volume. Vt, column volume or total volume of the packed bed volume. were obtained in radial nerve extracts of H. pervicax. Fractionation range in molecular weight of Sephadex G-50 is 1500-30,000 d ('Sephadex gel-filtration in theory and practice' from Pharmacia Fine Chemicals). The extrusion limit in Sephadex G-15 is reported as 1500 d. Therefore, the molecular weight of the radial nerve factor appears to be larger than 1500 but considerably smaller than 30,000. This implies that the radial nerve factor is a peptide with molecular weight of several thousands' daltons. Presence of a secondary factor for oocyte maturation Ovaries or testes (2-3 g, wet weight) of//, leucospilota were separately incubated with 1 ml of radial nerve homogenate (50 or 100 mg/ml) for 2 or 3 hours. After removing gonads and spawned oocytes (or sperm in males) by low-speed centrifu- gation, the incubation mixtures were centrifuged at 26,000 X g or 10,000 X g for 30 min at 4°C to remove cells or debris, and the resulting supernatants were assayed with follicle cell-free oocytes. The supernatant induced the maturation of follicle cell-free oocytes (Fig. 5). As shown in Table IV, ovaries or testes, in the
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