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61.
Shengjie Li Xi Chen Hongjie Zhang Xiangying Liang Yang Xiang Chaohui Yu Ke Zen Youming Li Chen-Yu Zhang 《Journal of lipid research》2009,50(9):1756-1765
Despite years of effort, exact pathogenesis of nonalcoholic fatty liver disease (NAFLD) remains obscure. To gain an insight into the regulatory roles of microRNAs (miRNAs) in aberrant energy metabolic status and pathogenesis of NAFLD, we analyzed the expression of miRNAs in livers of ob/ob mice, streptozotocin (STZ)-induced type 1 diabetic mice, and normal C57BL/6 mice by miRNA microarray. Compared with normal C57BL/6 mice, ob/ob mice showed upregulation of eight miRNAs and downregulation of four miRNAs in fatty livers. Upregulation of miR-34a and downregulation of miR-122 was found in livers of STZ-induced diabetic mice. These results demonstrate that distinct miRNAs are strongly dysregulated in NAFLD and hyperglycemia. Comparison between miRNA expressions in livers of ob/ob mice and STZ-administered mice further revealed upregulation of four miRNAs and downregulation of two miRNAs in livers of ob/ob mice, indicating that these miRNAs may represent a molecular signature of NAFLD. A distinctive miRNA expression pattern was identified in ob/ob mouse liver, and hierarchical clustering of this pattern could clearly discriminate ob/ob mice from either normal C57BL/6 mice or STZ-administered mice. These findings suggest an important role of miRNAs in hepatic energy metabolism and implicate the participation of miRNAs in the pathophysiological processes of NAFLD. 相似文献
62.
Yasuo Kato Yasuhisa Asano Akiko Nakazawa Kiyosi Kondo 《Biocatalysis and Biotransformation》1990,3(3):207-215
Synthesis of D-alanine oligopeptides from D-alanine methylester hydrochloride has been demonstrated by use of immobilized D-aminopeptidase from Ochrobactrum anthropi (Achromobacter sp.) in non-aqueous media. D-Alanine dimer and trimer were obtained in 56% and 6% yield, respectively, when 250 mM of the substrate was incubated for 3 hours with urethane-prepolymer immobilized D-aminopeptidase (1.5 U/ml) and 3 equivalents of triethylamine in water-saturated toluene. The kcat of this reaction was calculated to be 19,500 (min-1), which is several ten thousand times greater than that of the known enzymatic syntheses of amino acid oligomers. 相似文献
63.
G J Jackson 《Experimental parasitology》1973,34(1):111-114
Required for a nematode's reproduction in a chemically defined medium are the nine mammalian essential amino acids (sensu strictu). Needed in addition to lysine, tryptophane, histidine, phenylalanine, leucine, isoleucine, threonine, methionine, and valine is arginine which is marginally essential for mammals. Tyrosine, nonessential for mammals, is not absolutely required by the nematode but is beneficial in terms of onset time and quantity of reproduction. Aspartic acid, nonessential for the nematode and mammals, is toxic for adult nematodes at and above 4.8 mg/ml medium. The nematode, Neoaplectana glaseri, is parasitic in insect grubs but the strain used has been cultivated in species isolation on kidney slices continuously since (1944). 相似文献
64.
K. W. Dorschner 《Entomologia Experimentalis et Applicata》1993,68(1):31-41
Aphids, like most phloem-feeding insects, commonly exhibit a high degree of host specificity. Plant-specific chemical compounds
are likely to serve as important host selection cues for monophagous aphids and such substances could be present in aphid
honeydew. Apterous virginoparae ofMyzus persicae (Sulzer) andPhorodon humuli (Schrank) were reared on a buffered sucrose solution containing various aphid honeydews or a mixture of amino acids. In two
separate experiments, the host-specificP. humuli (hop aphid) could grow and reproduce only on diets containing honeydew collected from hop (Humulus lupulus L.).M. persicae (the green peach aphid, GPA) did not perform well on diets containing hop honeydew, perhaps because hop is a poor GPA host.
Honeydew collected from preferred GPA host plants rape,Brassica napus L., and jimsonweed,Datura stramonium L., allowed GPA growth and reproduction. Hop aphids, however, performed poorly on rape and jimsonweed honeydew diets. Bell
pepper,Capsicum annuum L., honeydew supported neither the hop aphid nor GPA. The study of aphid honeydew components may contribute towards a more
complete understanding of host preference and selection phenomena in aphids. 相似文献
65.
The inhibition of lipid synthesis in vitro in the locust, Schistocerca gregaria, by factors from the corpora cardiaca 总被引:1,自引:0,他引:1
ABSTRACT. The rate of lipid synthesis from [14 C]acetate in fat body from Schistocerca americana gregaria has been studied in vitro. Maximum incorporation is found on days 6–10 in adults and day 4 of the fifth stadium. The label appeared in the fatty acid components of triacyl-glycerol, diacylglycerol and phospholipid.
Lipid synthesis in vitro was inhibited by extracts of corpora cardiaca, and such inhibition was most marked (up to 85%) in fat bodies from insects at stages where fatty acid synthesis was greatest. HPLC separation of corpora cardiaca extracts gave several active fractions of which the most active was adipokinetic hormone 1 (AKH-1). 相似文献
Lipid synthesis in vitro was inhibited by extracts of corpora cardiaca, and such inhibition was most marked (up to 85%) in fat bodies from insects at stages where fatty acid synthesis was greatest. HPLC separation of corpora cardiaca extracts gave several active fractions of which the most active was adipokinetic hormone 1 (AKH-1). 相似文献
66.
Polysaccharide breakdown by mixed populations of human faecal bacteria 总被引:10,自引:0,他引:10
67.
68.
Summary. Both 1,4-benzoquinones and 1,4-naphthoquinones were attached to the non-proteinogenic amino acid taurine to form N-quinonyl
taurine derivatives. The products were formed via the direct Michael-like addition or by substitution of a good leaving group.
An attempt to bridge the two moieties via an ureido spacer resulted in the formation of a bis-quinonylamino isocyanurate derivative.
Preliminary MO calculations provided internal ground-state geometries and orbital coefficients of the HOMO levels in two representing
taurine conjugates.
Received May 6, 2002 Accepted August 13, 2002 Published online December 18, 2002
Acknowledgments This research was supported by the Israel Science Foundation founded by the Academy of Science and Humanities. We wish to
thank Ms. Ethel Solomon for skilled technical help.
Authors' address: Prof. Shmuel Bittner, Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel,
Fax: (972)-8-6472943, E-mail: bittner@bgumail.bgu.ac.il 相似文献
69.
70.
Lela Jovanovich Sally Levin M. A. Q. Khan 《Journal of biochemical and molecular toxicology》1987,2(3):203-213
Treatment of rats with mirex (40 ppm in diet) caused hypoglycemia, liver enlargement, and inhibition of adrenal corticosteroid-synthesizing enzyme activity. At toxic dosages (20,000 ppm mirex in diet, which has a lethal toxicity-50 [LT-50] of ten days) poisoned female rats showed severe hypoglycemia, fatty liver, adrenal hyperplasia, hypophagia, lipid mobilization, and body weight (bw) loss. A 50 μg/kg intraperitoneal (IP) dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in male rats caused similar effects two days posttreatment. Hypoglycemia could be overcome by prednisone (which also inhibited adrenocorticoid-synthesizing enzyme activities) but not by streptozotocin treatment, indicating that hypoglycemia may be related to glucocorticoid deficiency resulting from inhibition of their synthesis and not by direct effects on pancreatic β-cells. Glucocorticoid deficiency could also cause increased release of adrenocorticoid hormone (ACTH), which may enhance fat mobilization caused by hypophagia. 相似文献