. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. OBSERVATIONS ON D EYE 151 1 to o 3 a * w at « a a a <D 5 (0 00 1 s! 11. Figure 10. The extracellularly recorded ERG responses are cornea- negative potential changes with little or no positive component. Figure 11. The superimposed spectral response curves of eight ani- mals based on a criterion response of 50 /jV, clearly demonstrate a sin- gle sensitivity peak in the range of 512-549 nm wavelengths. entire retinula cell plasma of the light-adapted eye sug- gests the involvement of glycogen as an energy source du
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. OBSERVATIONS ON D EYE 151 1 to o 3 a * w at « a a a <D 5 (0 00 1 s! 11. Figure 10. The extracellularly recorded ERG responses are cornea- negative potential changes with little or no positive component. Figure 11. The superimposed spectral response curves of eight ani- mals based on a criterion response of 50 /jV, clearly demonstrate a sin- gle sensitivity peak in the range of 512-549 nm wavelengths. entire retinula cell plasma of the light-adapted eye sug- gests the involvement of glycogen as an energy source during the energy consuming process of light perception (HamdorfandKaschef, 1964; Evequoze/a/., 1983). The hypertrophied nature of the endoplasmic reticulum is consistant with, and probably signifies, intense visual pigment synthesis. The unquestionable increase in microvillus diameter during dark adaptation is somewhat surprising as this would offset the possible gain in sensitivity made by an overall enlargement of rhabdom volume. However, in- creases in microvillus diameters of a similar magnitude under dark conditions have been reported (Nassel and Waterman, 1979) in the crab Grapsiisgrapsus, in Gryllus bimaculatus (Hoff, 1985), and can also be calculated from electron micrographs on the eye of the brine shrimp Anemia salina (Hertel, 1980). They are also in agree- ment with observations by Yoshida and Kaga (1983) if we assume that their "dumbbell-shaped" microvilli in the light-adapted condition actually represented an oblique section through two rows of microvilli. Yoshida and Kaga (1983) state that in the cumacean Dimorphos- tylis asiatica the change from the 30-50 nm wider dark adapted to the narrower light adapted microvillar ultra- structure is completed in 10 minutes at 130 lux illumina- tion, but that it requires 3 times longer in reverse. Al- though not specifically tested in D. rathkei, this time course would agree with pigment granule displacements in art
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
