. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 84 ARTHUR C. GIESE Nereis, Chaetopterus, and Dendraster. Whether this is due to mere physical screening by some inert materials in the egg or to differences in concentration of some light sensitive materials is not known. Action spectra for egg and sperm If irradiation of the nucleus alone causes retardation of division of the cell, the same action spectrum should be found for egg and sperm; that is, there should be no qualitative difference in effectiveness of different wave-lengths even though the general susceptibility of
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 84 ARTHUR C. GIESE Nereis, Chaetopterus, and Dendraster. Whether this is due to mere physical screening by some inert materials in the egg or to differences in concentration of some light sensitive materials is not known. Action spectra for egg and sperm If irradiation of the nucleus alone causes retardation of division of the cell, the same action spectrum should be found for egg and sperm; that is, there should be no qualitative difference in effectiveness of different wave-lengths even though the general susceptibility of the sperm is greater. If elements in the cell other than the ACTION SPECTRA FOR SPERM AND EGG AND PROTEIN ABSORPTION 100 i- i I I i \ ABSORPTION BY SERUM ALBUMIN ' SPERM ACTION SPECTRUM \ ABSORPTION BY NUCLEIC ACID EGG ACT/ON SPECTRUM. 20 - £300 2500 270O 2900 3100 WAVELENGTH IN ANGSTROM UNITS FIGURE 2. Comparison of the action spectra of Figure 1 with absorption spectra of nucleic acid and serum albumin. Data for nuclei acid from Caspersson (1938), for proteins from Smith (1929). Note that the action spectrum for the egg is quite different from the absorption spectrum for albumin at both ends. nucleus are involved the egg may show an action spectrum different from that of the sperm. The methods employed for the studies at different wave-lengths are similar to those already described elsewhere (Giese, 1938, 1939c), therefore, only the briefest mention need be made of them. The irradiated eggs are fertilized with normal sperm. The rate of division is then determined by observing for percentage of cleavage every 15 minutes. The times at which the eggs reach the 2, 4, 8, 16, and 32 cell stages are recorded and the number of cleavages is plotted against the time after fertilization and compared with the control. The increase in time required to reach the third cleavage is taken as a measure of the retarding action of the radi-. Please note that these images are extracted from sca
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
