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101.
Vasoactive intestinal peptide (VIP) and peptide histidine isoleucine (PHI) are homologous neuropeptides which share vasodilatory properties. This paper addresses the question of whether PHI exerts its vascular action via a receptor distinct from that for VIP. Radioligand binding experiments were done using [Tyr(125I)10]VIP, [Tyr(125I)22]porcine PHI, [Tyr(125I)10]rat PHI and arterial preparations from rat, bovine and porcine species. The radioiodination of rat PHI by the lactoperoxidase-glucose oxidase method and analysis of the structure of the major radiolabeled derivatives were described. All the receptor binding experiments identified a VIP-preferring receptor irrespective of which radioligand or arterial preparation was utilized. VIP and PHI peptides demonstrated cross-desensitization in studies of relaxation of porcine coronary arterial strips in vitro. The present results favor the conclusion that the vascular actions of the PHI peptides are best explained by binding to a VIP-preferring receptor. 相似文献
102.
103.
Genetic Analysis of Olfactory Behavior in Drosophila: A New Screen Yields the Ota Mutants 总被引:5,自引:3,他引:2 下载免费PDF全文
A simple means of measuring Drosophila olfactory response is described, and the behavior which it measures is characterized. The assay was used to screen for X-linked mutants defective in olfactory function. Six ota mutants were isolated and characterized (ota = olfactory trap abnormal). Four of the mutants were found to be abnormal in another chemosensory behavior as well. Two of the mutant phenotypes extend to include another sensory system: they are defective in visual system physiology. All were normal, however, in a test of giant fiber system physiology. Two of the mutations are dominant, and the recessive mutations define two complementation groups. Mutations representing each complementation group, as well as one of the dominant mutations, were mapped. For the mutants with defective visual system physiology, the visual defects were shown to cosegregate with olfactory phenotypes. 相似文献
104.
Molecular genetics of phenylketonuria in Orientals: linkage disequilibrium between a termination mutation and haplotype 4 of the phenylalanine hydroxylase gene. 总被引:11,自引:8,他引:3 下载免费PDF全文
T Wang Y Okano R Eisensmith S Z Huang Y T Zeng W H Lo S L Woo 《American journal of human genetics》1989,45(5):675-680
Phenylketonuria (PKU) is a common metabolic disorder among Chinese, with a prevalence of about 1 in 16,500 births. This frequency is very similar to that among Caucasians. Individual exons of the phenylalanine hydroxylase (PAH) gene with flanking introns were amplified by polymerase chain reaction and cloned into M13 for sequence analysis. An Arg111-to-Ter111 mutation has been identified in exon 3 of the PAH gene in a Chinese PKU patient. The mutation is in linkage disequilibrium with the mutant haplotype 4 alleles which are the most prevalent haplotype among the Orientals. The mutation accounts for about 10% of the Chinese PKU alleles and is absent from the Caucasians, demonstrating that independent mutational events have occurred in the PAH locus after racial divergence. 相似文献
105.
Tyrosine phosphorylation in human neutrophil 总被引:9,自引:0,他引:9
J Gomez-Cambronero C K Huang V A Bonak E Wang J E Casnellie T Shiraishi R I Sha'afi 《Biochemical and biophysical research communications》1989,162(3):1478-1485
Protein tyrosine phosphorylation in human neutrophils was examined by immunoblotting with antibodies specific for phosphotyrosine. The addition of the human hormone granulocyte-macrophage colony stimulating factor to human neutrophils caused an increase in the tyrosine phosphorylation levels of several proteins. The increases in at least two of these proteins having molecular masses of 40 kDa (p40) and 54 kDa (p54) were rapid and were inhibited in pertussis toxin treated cells. The newly synthesized tyrosine kinase inhibitor ST 638 inhibited the increases in the levels of the tyrosine phosphorylation in p92, p78, p54 and p40 proteins. The epidermal growth factor receptor tyrosine kinase inhibitors were less effective. The addition of the chemotactic factor fMet-Leu-Phe to human neutrophils also caused an increase in tyrosine phosphorylation in some of these proteins. The pattern of the fMet-Leu-Phe-induced tyrosine phosphorylation was different from that produced by GM-CSF. The increases were also inhibited by ST 638. In addition, ST 638 inhibited superoxide production but not actin polymerization in control and GM-CSF-treated cells stimulated with fMet-Leu-Phe. Moreover, the active but not inactive phorbol esters increase the tyrosine phosphorylation only in the 40 kDa protein. These results suggest several points: (a) some of the responses produced by GM-CSF and fMet-Leu-Phe are mediated through tyrosine phosphorylation, (b) the GM-CSF receptor is coupled to a pertussis toxin sensitive G-protein, (c) the 40 kDa protein is probably the Gi alpha 2, and (d) the 78 or the 92 kDa protein is most likely the receptor for GM-CSF, which indicates that the receptor may have a tyrosine kinase domain. 相似文献
106.
A new compound, withangulatin A, promotes type II DNA topoisomerase-mediated DNA damage 总被引:1,自引:0,他引:1
J K Juang H W Huang C M Chen H J Liu 《Biochemical and biophysical research communications》1989,159(3):1128-1134
Withangulatin A, a new compound with a known chemical structure and from the antitumor Chinese herb Physalis angulata L, was found to act on topoisomerase II to induce topoisomerase II-mediated DNA damage in vitro. It has two effective dosage ranges of approximate 0.5 and 20 microM, with about one-third the activity of 20 microM VM-26. 相似文献
107.
We have previously shown that pH-sensitive immunoliposomes can mediate a target-specific delivery of plasmid DNA to tumor cells grown in a mouse model [Wang, C.-Y., & Huang, L. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 7851-7855]. The efficiency of delivery in terms of the target cell transformation frequency has now been characterized for both short- and long-term gene expression in a tissue culture system. Herpes simplex virus thymidine kinase (TK) gene was used as a reporter gene. It was placed under the control of the promoter for the rat phosphoenolpyruvate carboxykinase gene, which contains a cAMP regulatory element. Therefore, the expression of the exogenous gene in the target cell, mouse Ltk- cells, can be regulated by cAMP drugs. The plasmid DNA was encapsulated in liposomes using a detergent dialysis method. The efficiency of gene delivery was optimized with respect to the time course and dose of liposome-associated DNA. The existence of antibody of the liposomes was essential for the maximal level of DNA delivery. Delivery was also dependent on the lipid composition of the liposome. The pH-sensitive lipid composition gave 8-fold higher efficiency than the corresponding pH-insensitive composition. The transformation efficiency of the target cell also depended on the regulation of gene expression; cells incubated with dibutyryl-cAMP and theophylline showed a much higher level of transformation frequency than cells incubated without the drugs. When all liposome and incubation parameters are optimized, the Ltk- cells showed a 47% efficiency for the short-term transformation, and 2% for the long-term transformation.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
108.
Y Hashimoto K Chida M Huang M Katayama T Nishihira T Kuroki 《Biochemical and biophysical research communications》1989,163(1):406-411
The protein kinase C (PKC) activities of tumor tissue and adjacent normal mucosa of human cancers of the esophagus (8 cases), stomach (1 case) and colon (3 cases) were measured. Considerable variations were found in the activity of PKC and in its subcellular distribution in these cancers. The PKC activities of the membrane and cytosolic fractions of the eight esophageal cancers were, however, similar to those of the adjacent normal mucosa: the average PKC activities of the tumor tissues and normal mucosa were 7.5 and 8.3 pmol/min/mg protein, respectively, in their membrane fractions and 7.9 and 7.8 pmol/min/mg protein, respectively, in their cytosolic fractions. 相似文献
109.
A glutathione transferase from human mononuclear leukocytes with a high activity towardtrans-stilbene oxide (GT-tSBO) has been studied in liver and blood from fetus and adults and in blood from neonates. Using starch gel electrophoresis, different phenotypes of GST1 have been determined, GST1 0, GST1 1, and GST1 2. As judged from activity measurements and the fact that only those individuals who express the null allele of GST1, the GST1 0, which has a low activity towardtrans-stilbene oxide, it is concluded that the hepatic transferase GST1 is identical to GT-tSBO, as well as to hepatic transferase μ. In addition, it has been shown that the different genotypes of GST1 1 (GST1 1-1, GST1 1-0) and GST1 2 (GST1 2-2, GST1 2-0) can be separated by measuring the GT-tSBO activity in whole blood from the same individual. It is also demonstrated that GT-tSBO activity is much lower in fetal liver, approximately 10 times, compared with adult liver, while this activity seems to be unchanged in the blood from fetus and adults, as well as in neonates. 相似文献
110.
Trigramin: primary structure and its inhibition of von Willebrand factor binding to glycoprotein IIb/IIIa complex on human platelets 总被引:9,自引:0,他引:9
Trigramin, a naturally occurring peptide purified from Trimeresurus gramineus (T. stejnegeri formosensis) snake venom, inhibits platelet aggregation and the binding of 125I-fibrinogen to ADP-stimulated platelets (Ki = 2 X 10(-8) M) without affecting the platelet-release reaction. 125I-trigramin binds to ADP-stimulated and to chymotrypsin-treated normal platelets but not to thrombasthenic platelets. 125I-trigramin binding to platelets is blocked by monoclonal antibodies directed against the glycoprotein IIb/IIIa complex and by Arg-Gly-Asp-Ser (RGDS) [Huang et al. (1987) J. Biol. Chem. 262, 161]. We determined the primary structure of trigramin, which is composed of a single polypeptide chain of 72 amino acid residues and six disulfide bridges. The molecular weight of trigramin calculated on the basis of amino acid sequence was 7500, and the average pI was 5.61. An RGD sequence appeared in the carboxy-terminal domain of trigramin. An amino-terminal fragment (7-33) of trigramin showed 39% homology with a region (1555-1581) of von Willebrand factor (vWF). Trigramin also showed 36% identity in a 42 amino acid overlap and 53% identity in a 15 amino acid overlap when compared with two adhesive proteins, collagen alpha 1 (I) and laminin B1, respectively. Trigramin blocked binding of human vWF to the glycoprotein IIb/IIIa complex in thrombin-activated platelets in a dose-dependent manner. Reduction of trigramin resulted in a marked decrease in its ability to block vWF binding to human platelets.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献