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71.
The purpose of this study is to investigate the effect of Cr deficiency on the rat retina. Three-week-old Wistar Kyoto rats were divided into 2 groups. Cr-deficient rats were fed AIN-93G diet without Cr and deionized distilled water. Control rats were fed AIN-93G diet and deionized distilled water. The Cr and sugar concentrations in the whole blood and cholesterol concentration in the serum were measured. We observed the retina with an electron microscope, and counted phagocytized lamellar structures in the retinal pigment epithelium (RPE) before and after the start of light exposure on negative electron microscopic films. The whole blood Cr level of Cr-deficient rats was less than 0.2 microg/l. The blood sugar level of Cr-deficient rats was significantly higher than that of normal rats (p < 0.05). There were significantly more phagocytized lamellar structures in the RPE of Cr-deficient rats 1, 2, 7, 11 and 12 h after the start of light exposure than in that of normal rats (p < 0.05). However, no morphological abnormalities were found in the photoreceptor cells of Cr-deficient rats. Phagocytosis in the photoreceptor outer segment discs in the RPE was accelerated, but the pattern of the retinal circadian rhythm with maximum phagocytosis 2 h after exposure to light was unchanged. The Cr-deficient state may cause the membrane to degenerate, and phagocytosis of the photoreceptor outer segment discs in the RPE may be accelerated. This study provided an evidence of the nutritional importance of Cr in rat retina. 相似文献
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74.
Functional analysis of water channels in barley roots 总被引:1,自引:0,他引:1
75.
Ishihara K Oyaizu S Mizunoya W Fukuchi Y Yasumoto K Fushiki T 《Bioscience, biotechnology, and biochemistry》2002,66(2):426-429
The author modified a respiratory gas analyzer to analyze the respiratory 13CO2 of 12 small laboratory animals all at once. To investigate the practical use of this system, mice were orally (OR) or intravenously (i.v.) given glucose solutions containing three different amounts of 13C-labeled glucose. Expired 13CO2 derived from exogenous glucose was detected within 10 minutes after administration in OR mice, but about 30 minutes in i.v. mice. The height of the peak of 13CO2 expiration was correlated with the administered 13C-glucose mass. 相似文献
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A sex difference in the penetration of selenium into the brain was observed using lipopolysaccharide (LPS)-injected mice.
The selenium concentration increased in the brains of sodium selenite-injected LPS-treated female mice, but not males. The
selenium concentration peaked when selenite was injected 3 h after the injection of LPS into female mice. In addition, selenium
in the brain increased when a dosage of 30 μmol/kg and more of selenite was injected into LPS-treated female mice. Also, the
selenium concentration in the brain increased and peaked 2–3 h after selenite injection; 24 h later, the level was similar
to the Se-only group. The penetration of selenium into the brain was inhibited by pretreatment with aminoguanidine, an inhibitor
of nitric oxide synthetase. From the present results, selenium more easily penetrated into the brains of female mice compared
to males after LPS treatment, and nitric oxide may have affected the penetration. However, the sex difference mechanism for
selenium penetration needs further investigation. 相似文献
78.
The entire amino acid sequence of bifunctional alginate lyase from Pseudoalteromonas sp. strain No. 272 were determined by two approaches, Edman degradation of the peptides obtained from protease digestion of the enzyme protein and analysis of PCR products of the structural gene. The former resulted in incomplete amino acid sequence in the entire sequence, due to lacking of the proper peptides from the protease digestion. To compensate for this lack of sequences we applied the method of PCR of the structural gene that was initially elucidated from the primers designed from N- and C-terminal amino acid sequences of the enzyme. The results of the amino acid sequences from these two approaches showed good agreement. The enzyme consisted of 233 amino acid residues with a molecular mass of 25,549.5, including the sole W and cystine residue. The sequence homology search among the other alginate lyases from different origins indicated that they were very weakly homologous, with the exception of the sequence homology (80.3%) of Pseudoalteromonas elyakovii alginate lyase. The consensus sequence, YFKhG + Y-Q (Wong, T. Y., Preston, L. A., and Schiller, N. L. 2000. Annu. Rev. Microbiol.
54: 289–340) in the C-terminal regions was conserved. The kinetic analyses of chemical modification of some amino acid residues of the enzyme showed that W, K, and Y appeared to be important in the enzyme function. 相似文献
79.
Kagawa Y Yanagisawa Y Hasegawa K Suzuki H Yasuda K Kudo H Abe M Matsuda S Ishikawa Y Tsuchiya N Sato A Umetsu K Kagawa Y 《Biochemical and biophysical research communications》2002,295(2):207-222
The "thrifty" genotype and phenotype that save energy are detrimental to the health of people living in affluent societies. Individual differences in energy metabolism are caused primarily by single nucleotide polymorphisms (SNPs), some of which promote the development of obesity/type 2 diabetes mellitus. In this review, four major questions are addressed: (1) Why did regional differences in energy metabolism develop during evolution? (2) How do genes respond to starvation and affluence? (3) Which SNPs correspond to the hypothetical "thrifty genes"? (4) How can we cope with disease susceptibility caused by the "thrifty" SNPs? We examined mtDNA and genes for energy metabolism in people who live in several parts of Asia and the Pacific islands. We included 14 genes, and the SNP frequencies of PPAR gamma 2, LEPR, and UCP3-p and some other genes differ significantly between Mongoloids and Caucasoids. These differences in SNPs may have been caused by natural selection depending on the types of agriculture practiced in different regions. Interventions to counteract the adverse effects of "thrifty" SNPs have been partially effective. 相似文献
80.