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The micelle structure of a homologous series of the fatty acid sucrose monoester, C S E (n = 10, 12, 14, 16), was systematically studied by X-ray scattering technique. The contrast variation method was used by changing the concentration of sucrose in solutions, and the obtained scattering data were converted into the absolute intensities. The data were corrected for the intermicellar interference effect. The morphological parameters such as micelle volume v I , average electron density p l , radius of gyration of micelle shape R,, second moment of the electron density distribution a, and square average of the electron density distribution were determined from the data in the range of 0 I s I 0.074 A-1, -where s = 2 sin 8/A, 28 is the scattering angle, and A is the wavelength of X-ray. The v l , R,, and a increase but pl and (Apl)* decrease with increasing chain length of fatty acid. From relations among R, maximum dimension of micelle, and first isoscattering point, it is suggested that the micelles are not spherical in shape. The other parameters such as aggregation number, hydration ratio, etc. were also obtained in this study. Logarithms of the aggregation number and the micelle volume were found to show excellently linear dependence on the chain length. The models of micelle structure were constructed on the basis of the morphological parameters. Since the two-shell structure of ellipsoid of revolution was found to be an unsuitable model for the sucrose ester micelles, the micelle was modeled by three-shell structure of polar group layer, hydrocarbon core, and the terminal methyl group region which localizes at the center of core. The best fitted model was selected by R factors calculated for both the intensity curves and distribution functions. The micelle shape was oblate for Cl$E, C1+SE, and C , S E but prolate for C1$E. X-ray scattering curves show a possibility that both types of ellipsoid coexist in the solution of C1$E at 20 OC. Many structural parameters were found to change systematically with length of the hydrocarbon chain. However, the minor semiaxial length of hydrophobic core does not change consistently with the increase of chain length. This suggests the increase of gauchetrans-gauche (kink) sequence with increasing the chain length. It is also suggested that water molecules enter into near the boundary between hydrophobic core and hydrophilic layer but do not penetrate into the hydrophobic core. The polydispersity in micelle size was found to be small as a result of the model calculations assuming the Gaussian distribution of the micelle size. The structural change of CI6SE micelle was found at 49% (w/v) sucrose concentration and interpreted as the change in the packing mode of the detergent molecule and/or the hydration.

The deep-sea bioluminescent squid, Watasenia scintillans, has three visual pigments: The major one (A1 pigment) is based on retinal and has 2max=484 nm, the second one (A2 pigment) is based on 3-dehydroretinal and has 2m~x = 500 rim, and the third one (A4 pigment) is based on 4-hydroxyretinal and has )[m.x = 470 nm. The distribution of these 3 visual pigments in the retina was studied by HPLC analysis of the retinals in retina slices obtained by microdissection. It was found that A1 pigment was not located in the specific region of the ventral retina receiving the down-welling light which contains very long photoreceptor cells, forming two strata. A2 and A4 pigment were found exclusively in the proximal pinkish stratum and in the distal yellowish stratum. The role of these pigments in the retina is hypothesized to involve spectral discrimination. The extraction and analysis of retinoids to determine the origin of 3-dehydroretinal and 4-hydroxyretinal in the mature squid showed only a trace amount of 4-hydroxyretinol in the eggs. Similar analysis of other cephalopods collected near Japan showed the absence of A2 or A4 pigment in their eyes.

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