The DNA and amino acid sequences of the membrane-spanning region of the GABA receptors of the German cockroach have been identified along with information on the nature and the specific site of mutation in the cyclodiene-resistant strains. In this resistant strain, the mutation has occurred at the most conserved, lower M2 cylinder region involving a G to T conversion, resulting in an amino acid change of alanine (GCC) residue to serine (TCC). The site, furthermore, coincides with the most conserved region of all GABA receptor subunits and the expected Cl- transporting segment constituting the innermost surface of the channel opening. The deduced sequence of the German cockroach GABA receptor differs from that of Drosophila mainly in the connecting region between M3 and M4.
{"title":"Identification of the site of mutation within the M2 region of the GABA receptor of the cyclodiene-resistant German cockroach.","authors":"K Kaku, F Matsumura","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The DNA and amino acid sequences of the membrane-spanning region of the GABA receptors of the German cockroach have been identified along with information on the nature and the specific site of mutation in the cyclodiene-resistant strains. In this resistant strain, the mutation has occurred at the most conserved, lower M2 cylinder region involving a G to T conversion, resulting in an amino acid change of alanine (GCC) residue to serine (TCC). The site, furthermore, coincides with the most conserved region of all GABA receptor subunits and the expected Cl- transporting segment constituting the innermost surface of the channel opening. The deduced sequence of the German cockroach GABA receptor differs from that of Drosophila mainly in the connecting region between M3 and M4.</p>","PeriodicalId":79328,"journal":{"name":"Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology","volume":"108 3","pages":"367-76"},"PeriodicalIF":0.0,"publicationDate":"1994-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18879517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bovine serum albumin (BSA) was exposed to hydroxyl radicals generated by the Fenton reaction. The reaction of the BSA solution with hydroxyl radicals resulted in a colour change from clear transparent to dark brown. The reaction was followed spectrophometrically. It was observed that during the reaction of BSA with hydroxyl radicals, a melanin-like absorption spectrum developed. The reaction with ferricyanide and the dark brown BSA solution resulted in the same dark blue-green colour as is typical for melanin. The results suggest that, by the reaction of BSA with hydroxyl radicals, melanin was formed.
{"title":"Transformation of albumin into melanin by hydroxyl radicals.","authors":"U Schraermeyer","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Bovine serum albumin (BSA) was exposed to hydroxyl radicals generated by the Fenton reaction. The reaction of the BSA solution with hydroxyl radicals resulted in a colour change from clear transparent to dark brown. The reaction was followed spectrophometrically. It was observed that during the reaction of BSA with hydroxyl radicals, a melanin-like absorption spectrum developed. The reaction with ferricyanide and the dark brown BSA solution resulted in the same dark blue-green colour as is typical for melanin. The results suggest that, by the reaction of BSA with hydroxyl radicals, melanin was formed.</p>","PeriodicalId":79328,"journal":{"name":"Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology","volume":"108 3","pages":"281-8"},"PeriodicalIF":0.0,"publicationDate":"1994-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18879620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The radioligand binding assay of A1 adenosine receptors in adipocyte crude plasma membrane from Yucatan miniature swine was optimized by evaluating 17 factors involved in the assay. Significant effects of CHAPS, adenosine deaminase, EDTA, pre-rinsing glass fiber filters and pH were found for the binding measurements. Using the optimized procedure, [3H]8-cyclopentyl-1,3-dipropylxanthine, ([3H]-DPCPX) binding to A1 adenosine receptors in swine subcutaneous adipocyte crude plasma membrane was measured; Bmax and Kd values were 479 +/- 77 fmol/mg protein and 0.87 +/- 0.10 nM, respectively. Values for mesenteric adipose tissue from sedentary swine and subcutaneous adipose tissue from exercise-trained swine were also measured.
{"title":"Characterization of the swine adipocyte A1 adenosine receptor using an optimized assay system.","authors":"Q Dong, J Schuchman, G B Carey","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The radioligand binding assay of A1 adenosine receptors in adipocyte crude plasma membrane from Yucatan miniature swine was optimized by evaluating 17 factors involved in the assay. Significant effects of CHAPS, adenosine deaminase, EDTA, pre-rinsing glass fiber filters and pH were found for the binding measurements. Using the optimized procedure, [3H]8-cyclopentyl-1,3-dipropylxanthine, ([3H]-DPCPX) binding to A1 adenosine receptors in swine subcutaneous adipocyte crude plasma membrane was measured; Bmax and Kd values were 479 +/- 77 fmol/mg protein and 0.87 +/- 0.10 nM, respectively. Values for mesenteric adipose tissue from sedentary swine and subcutaneous adipose tissue from exercise-trained swine were also measured.</p>","PeriodicalId":79328,"journal":{"name":"Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology","volume":"108 3","pages":"269-80"},"PeriodicalIF":0.0,"publicationDate":"1994-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18879619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The beta-subunit of the insulin receptor from the muscle of the shrimp Penaeus japonicus exists as multiple subtypes with M(r) of 79,000, 77,000 and 75,000. Only the subunit of M(r) 79,000 is autophosphorylated after the addition of insulin. The autophosphorylation occurred specifically at Tyr residues, as demonstrated by the specific subsequent dephosphorylation by the phosphotyrosyl protein phosphatase from the human placenta. The detergent, Triton X-100, and the metal ion, Mn2+, caused a noticeable enhancement of the autophosphorylation of shrimp insulin receptors from the muscle. Okadaic acid activated the kinase activity of the insulin-stimulated insulin receptor, but not the basal activity of the insulin receptor without the addition of insulin. Further studies comparing the insulin binding of the shrimp insulin receptor in the regulation of kinase activity of the multiple beta-subunit subtypes from the shrimp muscle are under way.
{"title":"Characterization of insulin receptor from the muscle of the shrimp Penaeus japonicus (Crustacea: Decapoda).","authors":"N N Chuang, P C Wang","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The beta-subunit of the insulin receptor from the muscle of the shrimp Penaeus japonicus exists as multiple subtypes with M(r) of 79,000, 77,000 and 75,000. Only the subunit of M(r) 79,000 is autophosphorylated after the addition of insulin. The autophosphorylation occurred specifically at Tyr residues, as demonstrated by the specific subsequent dephosphorylation by the phosphotyrosyl protein phosphatase from the human placenta. The detergent, Triton X-100, and the metal ion, Mn2+, caused a noticeable enhancement of the autophosphorylation of shrimp insulin receptors from the muscle. Okadaic acid activated the kinase activity of the insulin-stimulated insulin receptor, but not the basal activity of the insulin receptor without the addition of insulin. Further studies comparing the insulin binding of the shrimp insulin receptor in the regulation of kinase activity of the multiple beta-subunit subtypes from the shrimp muscle are under way.</p>","PeriodicalId":79328,"journal":{"name":"Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology","volume":"108 3","pages":"289-97"},"PeriodicalIF":0.0,"publicationDate":"1994-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18879621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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