Molecular cloning and sequence analysis of guinea-pig NADPH-cytochrome P-450 oxidoreductase [corrected]

A cDNA clone coding for cytochrome P-450 oxidoreductase was isolated from a guinea-pig liver cDNA library. The cDNA, MSr2, contained a complete coding region of 678 amino acids. The amino acid sequence of the guinea-pig cytochrome P-450 oxidoreductase showed approx. 90% identities with those of rat, human, rabbit, pig enzymes indicating conservation of primary structure of the enzyme during evolutionary divergence of species. The high conservation of acidic residues of the enzyme sustained the importance of them to maintain its function [corrected].     

Tissue esterases ofExoristina sorbillans (Uzi fly)

Polyacrylamide gel disc electrophoretic technique was used to examine the esterase pattern of nead, haemolymph, alimentary canal., ovary and testis of the Uzi fly. The zymograms revealed the varied pattern of esterases both in number and type. This varied pattern suggested several roles for these enzymes present in different tissues     

ATP(adenosine triphosphate)-vanadyl complex

Owing to the significance of inhibitory effect of vanadium ion to Na, K-ATPase, a complex formation between ATP and vanadyl ion was investigated over a wide pH range. Formations of two types of complex are observed : a blue complex formed in acidic and neutral pH regions and a green complex at higher than pH 11. On the basis of the results on potentiometric titration, optical and EPR spectra and empirical bonding coefficients calculated from the EPR parameters, two characteristic types of coordination environment are proposed for the ATP-vanadyl complex : a blue 1:1 complex is a relatively weak complex including a phosphate-vanadyl coordination mode, whereas a green 2:1 complex is much stronger complex including a vanadyl-oxygen coordination contributed from a deprotonated hydroxyl group of the ribose moiety of ATP.     

Grid map analysis and its application for detecting vegetation changes in Japan

Abstract. Grid maps are used as a basic vegetation data base in Japan; they are simplified from vector-based vegetation maps. We estimated the frequency error or lack of information corresponding to reduced resolution and examined the reliable limits of this data base. We produced 10 grid maps on five different scales from 50 m to 1000 m using two different methods using both the whole cell (W-method) and only the central circle (C-method) from a vegetation map at scale 1: 25 000. We found that patches larger than the area of a cell on a vector-based map could be kept almost certainly on any map, but many patches of less than the cell size were lost. The number of missing patches with the C-method is fewer at every scale than those with the W-method. Though the value of Morisita's Cλ (p) index showed that the similarity with the original map was high - from the 50-m to the 200-m resolution - it was increasingly lower on the 400-m and 1000-m grid maps. The values of the Shannon index on the original map, 50-m and 100-m grid maps were not different, but they decreased from the 200-m to 1000-m grid maps. Because the vegetation data base of the Japanese Environment Agency used a 1000-m C-method grid map, we found that much information on patches less than 100 ha had disappeared. Information about dominant vegetation or large patches is almost accurate in this data base.     

Coordinated distribution patterns of three enzyme activities involved in the absorption and metabolism of beta-carotene and vitamin A along the villus-crypt axis of chick duodenum.

The conversion of beta-carotene to retinal and the succeeding metabolic process of the retinal leading to production of retinol and retinyl esters are the prerequisite for the utilization of beta-carotene as a provitamin A. These processes are participated by beta-carotene cleavage enzyme, retinal reductase and retinol esterifying enzyme(s) in the small intestine. To examine whether these enzymes exhibit the coordinated distribution in the villus, we have used the cryostat sectioning technique to quantify the activities of beta-carotene cleavage enzyme, retinal reductase and retinol esterifying enzymes along the villus-crypt axis in 8-day-old chick duodenum. The beta-carotene cleavage enzyme activity was very low in the crypt and gradually increased, reaching a maximum in the mid-villus. The villus-crypt gradient of the beta-carotene cleavage enzyme activity corresponded with those of retinal reductase activity and lecithin: retinol acyltransferase (LRAT) activity, but distinct from that of acyl-CoA: retinol acyltransferase (ARAT) activity. Furthermore, the distribution of the content of retinyl esters was similar to that of LRAT activity. These results suggest that the beta-carotene cleavage enzyme is coordinately distributed along the villus-crypt axis with retinal reductase and LRAT, the two enzymes which require cellular retinol-binding protein, typeII (CRBPII) as the donor of the substrate.     

Heterosynaptic cross-talk of pre- and postsynaptic strengths along segments of dendrites

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