. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 126 EIZO NAKANO, KAYO OKAZAKI AND TAKASHI IWAMATSU concentration of added calcium ( mAI) was so low that no effect was found on the spicule formation, as reported by Okazaki (1956). At appropriate intervals, larvae were withdrawn from the culture and washed with sea water five times. They were then homogenized with M KG at pH in a Teflon homogenizer of the Potter type. The homogenate (called "total homogenate") was centrifuged in the cold at 800 y for 10 minutes and the sediment was discarded, while the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 126 EIZO NAKANO, KAYO OKAZAKI AND TAKASHI IWAMATSU concentration of added calcium ( mAI) was so low that no effect was found on the spicule formation, as reported by Okazaki (1956). At appropriate intervals, larvae were withdrawn from the culture and washed with sea water five times. They were then homogenized with M KG at pH in a Teflon homogenizer of the Potter type. The homogenate (called "total homogenate") was centrifuged in the cold at 800 y for 10 minutes and the sediment was discarded, while the supernatant ("supernatant") was used for analysis. A was placed on a stainless steel planchette, dried and counted with a thin end-window gas flow counter and an ordinary sealer. The samples for the determination of total nitro- gen were combusted and the nitrogen was estimated by direct Nesslerization. In the second series of experiments, larvae were reared in normal sea water until desired stages. They were then removed from the culture and incubated in the isotopic medium for two hours at room temperature. As the culture medium, artificial sea water containing Ca45 (1 /xc. nil.) was used. After incubation, larvae were washed repeatedly with sea water and divided into two parts. One part was homogenized with M KC1 and used for the counting of radioactivity as de- scribed above, while the remaining part was used for the examination of auto- radiographs in toto and in section. For making whole mount preparations, larvae were flattened and fixed with methanol between the slide and coverglass. After 10000 5000 01 1000 500 100. 10 12 15 18 21 24 27 Time after fertilization,hours 4 5 6 7 8 Stage number Total amimulalion ut" Ca'" in I'si-iKfaccnlrotiix larvae during development. I''ii the stage number see Table Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colo
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
