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Recent studies suggest that vitamin D may play a role in intestinal [Na.sup.+]-dependent phosphate transport adaptation to variable levels of dietary [P.sub.i]. Therefore, the goal of the current study was to assess [Na.sup.+]-dependent [P.sub.i] cotransport activity in transgenic mice to determine whether vitamin D is an essential mediator of this process. Intestinal brush-border membrane (BBM), [Na.sup.+]-dependent [P.sub.i] cotransport activity was significantly decreased in vitamin D receptor (VDR) null [VDR (-/-)] mice compared with wild-type (VDR+/+) mice. While intestinal Na-[P.sub.i] cotransporter (type IIb) mRNA levels were similar in VDR (-/-) and VDR (+/+) mice, type IIb Na-[P.sub.i] cotransporter protein expression was markedly suppressed in VDR (-/-) mice compared with VDR (+/+) mice. Furthermore, Na-[P.sub.i] cotransport activity in renal BBM was similar in VDR (-/-) and VDR (+/+) mice, but type IIa Na-[P.sub.i] cotransporter protein expression was decreased in VDR (-/-) mice. After administration of a low-[P.sub.i] diet, type IIb protein expression was significantly increased in VDR (+/+) and VDR (-/-) mice, and type IIb protein expression was present in the intestinal BBM of VDR (-/-) mice. These data demonstrate that intestinal Na-[P.sub.i] cotransport adaptation to a low-[P.sub.i] diet occurs independently of vitamin D. dietary phosphate; phosphate transport; intestine

A study to elucidate the mechanism of antioxidation activity of trehalose is conducted. Results indicate that the site to which trehalose could bind is not limited to polar groups and that this property of trehalose is not shared with neotrehalose.

It is known that the absorption maximum of halorhodopsin is red shifted by 10 nm with the uptake of a chloride ion CI(super -). The photon energy absorbed not only excites the chromophore but also changes the electrostatic energy of the protein environment.

Solid-state nuclear magnetic resonance spectroscopy can be used to analyze the local structure of phospholipid/amine polyion complexes in lyophilized powders of dipalmitoylphosphatidic acid(DPPA)/poly-L-lysine(pLYS) and DPPA/poly-L-arginine(pARG). It was possible to explain the behaviours of 31P chemical shielding tensor for the phosphate group in the two polyion complexes.

The authors discuss enantioselective Diels-Alder reaction of nonactivated dienes with glyoxylate esters and arylglyoxals. The use of cationic BINAP-palladium and -platinum complexes as chiral catalysts is analyzed.

Research was conducted to examine the physical origin of the opsin shift of bacteriorhodopsin and to provide a comprehensive analysis based on medium effect theory of absorption spectra. An empirical relationship between the absorption maximum of protonated retinal Schiff base and physical parameters of solvent were obtained using regression analysis. Results indicate that the effects of the protein are independent of each other although they are significantly correlated.

The secondary structures of poly(L-lysine) (pLYS) and poly(L-argine) (pARG) in the complex samples with dipalmitoylphosphatidic (DPPA) were characterized using 13C cross polarization and magic angle spinning (MAS) nuclear magnetic resonance (NMR). Each amino acid residue of the basic polypeptides, pLYS and pARG, possessed a positive charge in the side chain indicating its link to negatively charged acidic phospholipids. It was discovered that a beta-sheet conformation was produced by pLYS and a secondary structure of pARG was present on the surface of the DPPA membrane.

Stacking of poly(3-alkylthiophene)s P3RThs and poly(4-alkylthiazole)s P4RTzs has been studied. Light scattering analysis indicates that head-to-tail (HT) type HT-P3HexTh (R = n-[C.sub.6][H.sub.13]) gives a degree of depolarization ([[Rho].sub.v]) of 0.26 in CH[Cl.sub.3], which reveals that HT-P3HexTh takes a stiff structure even in the good solvent. Addition of C[H.sub.3]OH to CH[Cl.sub.3] solutions of HT-P3HexTh and head-to-head (HH) type HH-P4HepTz (R = n-[C.sub.7][H.sub.15)] leads to [Pi]-stacking of the polymer molecules to form stable colloidal particles. The light scattering analysis of the colloidal solution of HT-P3HexTh in a 2:1 solution of CH[Cl.sub.3] and C[H.sub.3]OH reveals that HT-P3HexTh is aggregated in a parallel style. Results of filtration experiments using membranes with 0.20 and 0.02 [[micro]meter] pores agree with the degree of the aggregation. P3HexThs with irregular structures (P3HexTh (Fe) and P3HexTh (Ni) with HT/HH ratios of about 7/3 and 1/2, respectively) show a weaker trend to aggregate; however, P3HexTh (Fe) is considered to stack in a surface region of a stretched poly(ethylene terephthalate) PET film. A dichroism observed with the stretched PET film indicates that the [Pi]-[[Pi].sup.*] absorption as well as photoluminescence of the stacked P3HexTh molecules have a transition moment along the direction of the polymer main chain. X-ray diffraction analysis of HT-P3RThs and HH-P4RTzs reveals that they take a face-to-face stacked structure with an end-to-end packing mode, except for HT-P3MeTh (R = Me). HT-P3MeTh forms a face-centered lattice with an interlayer distance of 3.51 [Angstrom]. An alternative copolymer of bithiazole and 4,4[prime]-dibutylbithiazole is packed in an interdigitation mode. At temperatures below 0 [degrees] C, the HT-P3HexTh molecules are [Pi]-stacked in CH[Cl.sub.3], and the 1H NMR spectrum shows a severe magnetic effect on the thiophene ring. Solid 13C NMR data are also consistent with the [Pi]-stacking.

A method is proposed to estimate both green leaf area index (GLAI) and soil moisture ([h.sub.v]), based on radar measurements at the Ku-band (14.85 GHz) and C-band (5.35 GHz) frequencies. The Ku-band backscatter at large incidence angles was found to be independent of soil moisture conditions and could be used alone to estimate GLAI. Then, the Ku-band estimate of GLAI could be used with a measurement of C-band backscatter in a canopy radiative transfer model to isolate the value of [h.sub.v]. This concept was demonstrated with a set of Ku- and C-band synthetic aperture radar (SAR) backscatter data acquired over agricultural fields in Arizona. The demonstration showed promise for operational application of the method, though several limitations were identified. Since both Ku- and C-band [Sigma] [degrees] are sensitive to soil roughness, this approach must be applied only to fields of similar soil roughness or row direction. This limitation may be less serious for farm management applications since crop type and cultivation practices are generally well known and can be taken into consideration. Another limitation of the use of Ku- and C-band [Sigma] [degrees] is the apparent saturation of the Ku-band signal with increasing GLAI. Operational implementation of this approach will require dual-frequency sensors aboard an aircraft or orbiting satellite. Index Terms - Agriculture, airborne radar, radar applications, radar imaging/mapping, remote sensing, satellite applications, soil measurements, synthetic aperture radar, vegetation.

A research was conducted to study the purification of the extracellular polyhydroxybutyrate (PHB) depolymerase from the culture supernatant of Comamonas acidovorans and to examine its biochemical and kinetic properties. The function of the putative substrate-binding domain was determined through a fusion protein with glutathione S-transferase formed in Escherichia coli. Results indicated that the PHB depolymerase was composed of discrete domains connected by a linker region.

The conformation dependence of 13C chemical shifts for linear pi-conjugated compounds such as the chromophore of the visual pigment rhodopsin (Rh) is subjected to ab initio shielding calculations. The relationships between the conformation of 10 diene derivatives and the shieldings of unsaturated carbons are investigated. It is shown that the chromophore in Rh takes s-trans conformation around the C12-C13 bond.

The ab initio NMR-shielding calculations of rhodopsin (Rh) and bacteriorhodopsin (bR) retinal ring-chain conformations reveal that the Delta sigma(C8-C5) value can provide information on retinal chromophores. The bR chromophore has a 6-s-trans planar conformation with an electrostatic perturbation near the C5 carbon. The twisted C6-C7 bond in Rh may occur in 6-s-cis and 6-s-trans forms.

The analysis of the decarboxylation reaction of phenylcyanoacetic acid is presented. The reaction is catalyzed by cyclodextrins (CD) and affords a practical study of CD complexation. Results show that the aspects of CD-catalyzed decarboxylation are reproducible with a simple dielectric model which approxiamates the CD cavity as a lower dielectric constant medium. The enzymatic functions of CDs are affected by the reaction field from the cavity space. Also, the dielectric property of the reaction center may be different for each enzyme.