PHOTORECEPTOR CELL TYPES IN THE RETINA OF VARIOUS VERTEBRATE SPECIES: IMMUNOCYTOCHEMISTRY WITH ANTIBODIES AGAINST RHODOPSIN AND IODOPSIN

Types of photoreceptor cells in the retinas of 36 species of vertebrates (5 classes, 14 orders) were investigated immunocytochemically with monoclonal antibodies against chicken iodopsin (Io-mAb) and antiserum against bovine rhodopsin (Rh-As). In mammals, Rh-As labeled the outer segments of some photoreceptor cells in striped squirrels (a diurnal mammal) and those of most photoreceptor cells in mice (a nocturnal mammal), while Io-mAb labeled any photoreceptor cells in either of them. In all species of birds studied, Io-mAb labeled the principal and accessory members of double cones and single cones with a red oil droplet. Rh-As labeled single cones with a yellow or clear oil droplet in addition to rods. In turtles, both Rh-As and Io-mAb labeled single cones with a red or clear oil droplet and the principal (with a yellow oil droplet) and accessory members of double cones. This suggests that the visual pigments in these cones of turtles have common epitopes with bovine rhodopsin and chicken iodopsin. In Japanese grass lizards, single cones with a yellow oil droplet and double cones were immunoreactive to both Rh-As and Io-mAb. In snakes, rods and cones could not be distinguished but both positively and negatively stained cells were observed by the use of each antibody. In geckos, however, all photoreceptor cells were immunonegative to Io-mAb. In all species studied in amphibians, Rh-As labeled rods but not cones. Neither rods nor cones reacted with Io-mAb. In fishes, almost all species studied had well developed cones, and some of these cones were labeled by Rh-As. However, Io-mAb labeled the outer segments of some cones only in loaches. Rh-As labeled photoreceptor cells in all species of fishes studied. Thus, Rh-As recognized the outer segments of rods in all species studied from fishes to mammals, whereas the epitope recognized by Io-mAb is conserved in some species of fishes, most species of reptiles and all species of birds studied.     

Protonation-induced structural change of lyotropic liquid crystals in oley- and alkyldimethylamine oxides/water systems

Lyotropic phase behavior of the nonionic and the half-ionized oleyldimethylamine oxide (OlDMAO)/water systems was investigated using polarized light microscopy, small-angle X-ray diffraction, and differential scanning calorimetry. Nonionic OlDMAO formed isotropic micellar solution, nematic, hexagonal, cubic, and lamellar liquid crystalline phases as the surfactant concentration increased. In contrast, half-ionized OlDMAO (i.e., 1:1 mixture of the nonionic and the protonated species) had a greater tendency to form bilayer structures, and the phase diagram became quite similar to those of double-chained ionic surfactants rather than single-chained ones, despite the introduction of positive charges to the nonionic one. The preference of the bilayer structures in the half-ionized OlDMAO was interpreted in terms of the dimers stabilized by the hydrogen bond between the nonionic and protonated species. For alkyldimethylamine oxides with a saturated hydrocarbon chain (CnDMAO, chain length: n = 14, 16, and 18), the phase sequence of lyotropic liquid crystals was hardly affected by the protonation, but an elongation of the cylinders of the hexagonal phase was observed for the half-ionized C14DMAO. Consequently, it can be considered that the dominant bilayer formation of the half-ionized OlDMAO is attributed to the combined effect of the hydrogen-bonded dimer formation and the cis-double-bond configuration of the alkyl chain.     

Piezoelectricity and ferroelectricity in polyvinylidene fluoride

The dielectric, elastic and electrostrictive constants of polyvinylidene fluoride (pvdf) are influenced by thermal molecular motion, particularly at the glass transition temperature. High temperature poling is caused by both dipolar orientation and space-charge redistribution. Low temperature poling and dielectric hysteresis under a strong electric field are caused by crystalline dipolar orientation. The ferroelectric nature of pvdf is confirmed by x-ray and infrared analyses. The piezoelectric constants for a single crystal are theoretically calculated in agreement with experimental values. The piezoelectricity in poled films originates from the intrinsic piezoelectricity of the crystal and the residual polarization in the crystal coupled with electrostriction and dimensional change in the non-crystalline phase.     

Four-nucleon pickup reaction on 12 ⩽ A ⩽ 94 nuclei

The differential cross sections for the (d, ⁶Li) reaction on targets of ¹²C, ¹⁶O, ²⁴Mg, ⁴⁰Ca, ⁵⁸Ni and ⁹⁴Mo have been measured at E_d = 54.2 MeV. The measured angular distributions have been analyzed by finite-range DWBA calculations, and spectroscopic factors for an α-cluster transfer have been extracted. In the DWBA analysis using an optical model with a phenomenological Woods-Saxon potential, the spin-orbit part of the deuteron optical potential played a significant role in reproducing the measured angular distributions but the spin-orbit part of the ⁶Li optical potential had a minor effect. Relative spectroscopic factors extracted from the present data were compared with theoretical predictions together with the results from the (p, pα) reaction. The relative spectroscopic factors for 1p-shell nuclei were in quantitative agreement with theoretical predictions. However, there were certain discrepancies between the spectroscopic factors extracted from the (d, ⁶Li) reaction and those from the (p, pα) reaction, and the discrepancies increased with target mass number.     

Salt effect on bilayer phase transitions of dipalmitoylphosphatidylglycerol in saline water under high pressure

ABSTRACT

The phase transitions of dipalmitoylphosphatidylglycerol (DPPG) bilayer membrane at high NaCl concentrations under high pressure were investigated to construct the temperature–pressure phase diagram and to determine phase-transition properties. The constructed phase diagrams exhibited qualitative resemblance to that of the dipalmitoylphosphatidylcholine (DPPC) bilayer membrane: they showed the gel-phase polymorphism including the pressure-induced bilayer interdigitation. The phase-transition properties of the DPPG bilayer membrane changed in a salt concentration-dependent manner. We discussed the salt effect on the DPPG bilayer membrane from the variation in interactions between the polar head groups of the PG molecules.     

Multi-state transition for the thermal unfolding of certain globular proteins as evaluated from the analysis of DSC curve

Differential scanning calorimetry(DSC) has been performed on the thermally induced transitions of soybean trypsin inhibitor(STI) and of Taka-amylase A(TAA) in buffers by using the adiabatic differential heat capacity calorimeter. Thermodynamic parameters have been derived from the excess heat capacity curves and found to be ΔH = 19.8 ± 0.2 J/g and ΔC_p = 0.51 ± 0.02 J/(K g) for STI and ΔH = 37.4 ± 0.7 J/g and ΔC_p= 0.62 ± 0.09 J/(K g) for TAA.The theoretical DSC curves for the unfolding were drawn on the basis of van't Hoff relation and compared with the excess heat capacity curves observed. The unfolding of both the proteins may be characterized by a three-state process rather than a simple two-state process. This was best evident for TAA, but less evident for STI.     

Piezoelectricity in polymers and biological materials

The piezoelectric effect in polymers is usually explained in terms of the uniaxial orientation of the polymer crystallites and the classical piezoelectric property of these crystallites. Polarization caused by stress gradient seems to be necessary to the understanding of the geometrical relationship between stress and polarization. Studies of the temperature variation of the complex piezoelectric modulus have revealed a new type of relaxation phenomenon, which is closely related to elastic and dielectric relaxation. The possibility of a polymer piezoelectric transducer has been demonstrated by a microphone using an elongated film of poly-γ-methyl-L-glutamate. The physiological significance of piezoelectricity in biological polymers, such as its correlation with the growth mechanism of bone and with the sense of a mechanical stimulus, is worth further investigation.