Insect Biochemistry最新文献_第6页

A putative route to ecdysteroids: Metabolism of cholesterol in vitro by mildly disrupted prothoracic glands of Manduca sexta 外皮甾体的一种假定途径:体外胆固醇的代谢通过轻度破坏的Manduca sexta前胸腺

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90062-J

M.L. Grieneisen, J.T. Warren, S. Sakurai, L.I. Gilbert

{"title":"A putative route to ecdysteroids: Metabolism of cholesterol in vitro by mildly disrupted prothoracic glands of Manduca sexta","authors":"M.L. Grieneisen, J.T. Warren, S. Sakurai, L.I. Gilbert","doi":"10.1016/0020-1790(91)90062-J","DOIUrl":"10.1016/0020-1790(91)90062-J","url":null,"abstract":"<div>Mechanical disruption of day 7 fifth instar Manduca sexta larval prothoracic glands prior to in vitro incubation with [3H]cholesterol resulted in a dramatic 10-fold increase in its conversion to [3H]7-dehydrocholesterol (20–50%), when compared to intact gland incubations (2–5%). Both procedures resulted in a 0.5–2% conversion to [3H]ecdysteroids. Endogenous cholesterol levels also decreased by this same 20–50% during the incubation, suggesting that the added tracer [3H]cholesterol was equilibrated with the total endogenous cholesterol pool. Glands from earlier fifth instar larvae were capable of similar conversion of [3H]cholesterol to [3H]7-dehydrocholesterol but without concomitant conversion to [3H]ecdysteroids, while in day 7 glands, conversion to [3H]ecdysteroids was temporally correlated with both the in vitro secretory activity of intact glands and the endogenous hemolymph ecdysteroid titer. These data suggest that the rate-limiting step in ecdysteroid biosynthesis occurs after the synthesis of 7-dehydrocholesterol. In addition to 7-dehydrocholesterol and ecdysteroids, four intermediate polarity metabolites were detected following the incubation of disrupted prothoracic glands. One, M1, appears to be an immediate precursor of ecdysone and 3-dehydroecdysone. Another, M3, while not a precursor of the ecdysteroids, may be a degradation product of a proposed epoxide intermediate of 7-dehydrocholesterol. A hypothetical scheme for the biosynthesis of ecdysteroids from cholesterol is presented.</div>","PeriodicalId":13955,"journal":{"name":"Insect Biochemistry","volume":"21 1","pages":"Pages 41-51"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-1790(91)90062-J","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74379185","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}

引用次数: 38

Synthesis and secretion of egg-specific protein from follicle cells of the silkworm, Bombyx mori 家蚕卵泡细胞卵泡蛋白的合成和分泌

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90054-I

Yukihiro Sato, Okitsugu Yamashita

引用次数: 19

Ca2+/calmodulin and Ca2+/phospholipid-dependent protein kinases in the neural tissue of the honeybee Apis mellifera 蜜蜂神经组织中Ca2+/钙调素和Ca2+/磷脂依赖性蛋白激酶的研究

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90101-J

Kirsten Altfelder , Uli Müller , Randolf Menzel

{"title":"Ca2+/calmodulin and Ca2+/phospholipid-dependent protein kinases in the neural tissue of the honeybee Apis mellifera","authors":"Kirsten Altfelder , Uli Müller , Randolf Menzel","doi":"10.1016/0020-1790(91)90101-J","DOIUrl":"10.1016/0020-1790(91)90101-J","url":null,"abstract":"<div>The Ca2+/calmodulin and Ca2+/phospholipid-dependent protein kinases have been purified and characterized from neural tissue of the honeybee Apis mellifera. Ca2+/calmodulin-dependent protein kinase appeared as a multisubunit complex composed of three subunits that co-migrate with kinase activity during all purification steps. The three subunits had molecular weights of 52,000, 57,000 and 60,000, termed α, β′ and β, respectively. The α and β subunits are distinct peptides whereas β′ may have been generated from β by proteolysis. The Ca2+/calmodulin-dependent protein kinase required 0.1 μM calmodulin and about 1 μM Ca2+ for half-maximal activation. The Ca2+/phospholipid-dependent protein kinase (protein kinase C) was purified from honeybee neural tissue by using DEAE-Sephacel and phosphatidylserine-affinity chromatography. The molecular weight of the protein kinase C was about 80,000 as estimated by gelfiltration. Subjection to SDS-PAGE gave a single band with <math><mtext>M</mtext><msub><mi></mi><mn><mtext>r</mtext></mn></msub><mtext> = 80,000</mtext></math>, indicating that the enzyme exists as a monomer. The enzyme was fully activated by diacylglycerol in the presence of phospholipid and Ca2+.</div>","PeriodicalId":13955,"journal":{"name":"Insect Biochemistry","volume":"21 5","pages":"Pages 479-486"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-1790(91)90101-J","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75922242","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}

引用次数: 18

Isolation of nerve endings from the central nervous system of the cricket (Acheta domesticus) using a percoll gradient technique 使用percoll梯度技术从蟋蟀(Acheta domesticus)的中枢神经系统分离神经末梢

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90011-3

R.A. Nicholson, M. Connelly

引用次数: 4

The female reproductive accessory glands of the medfly Ceratitis capitata: Antibacterial activity of the secretion fluid 头角蝇雌性生殖副腺:分泌液的抑菌活性

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90029-E

Daniela Marchini , Luigi F. Bernini , Laura Marri , Piero C. Giordano , Romano Dallai

引用次数: 36

Characterization of a potent agonist of the insect octopamine-receptor-coupled adenylate cyclase 昆虫八胺受体偶联腺苷酸环化酶的强效激动剂的表征

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90024-9

Nailah Orr , Gregory L. Orr , Robert M. Hollingworth

{"title":"Characterization of a potent agonist of the insect octopamine-receptor-coupled adenylate cyclase","authors":"Nailah Orr , Gregory L. Orr , Robert M. Hollingworth","doi":"10.1016/0020-1790(91)90024-9","DOIUrl":"10.1016/0020-1790(91)90024-9","url":null,"abstract":"<div>The imidazoline, 2,3-xylylaminomethyl-2′-imidazoline (XAMI) was evaluated for its effects on octopamine-sensitive adenylate cyclase (OSAC) in crude membrane preparations of neural and non-neural tissues of the American cockroach, Periplaneta americana and ventral-nerve cord homogenates of the tobacco hornworm, Manduca sexta. In the cockroach nerve cord, XAMI was found to be a partial agonist with a Vmax 80% of p-octopamine (OA) and a Ka of 30 nM. The affinity is 185 times greater than that of OA. Additivity studies suggest that at maximally stimulating concentrations, XAMI interacts primarily with the OSAC. The antagonist profile for XAMI mimics that of OA with mianserin being the best antagonist, followed by the α-adrenergic antagonist phentolamine. These antagonists were shown to act competitively at the XAMI-binding site. β-adrenergic and dopaminergic antagonists were ineffective. These data indicate that XAMI has the highest reported affinity of any OA-receptor agonist and may be a suitable ligand for studies of the OA receptor.</div>","PeriodicalId":13955,"journal":{"name":"Insect Biochemistry","volume":"21 3","pages":"Pages 335-340"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-1790(91)90024-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79857208","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}

引用次数: 17

Purification and partial characterization of α-Amylase allozymes from the lesser grain borer, Rhyzopertha dominica 小螟虫α-淀粉酶同工酶的纯化及部分特性研究

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90020-F

James E. Baker

{"title":"Purification and partial characterization of α-Amylase allozymes from the lesser grain borer, Rhyzopertha dominica","authors":"James E. Baker","doi":"10.1016/0020-1790(91)90020-F","DOIUrl":"10.1016/0020-1790(91)90020-F","url":null,"abstract":"<div>α-Amylase was purified from adults of the lesser grain borer, Rhyzopertha dominica (F.), by ammonium sulfate precipitation, glycogen complex formation, and gel filtration chromatography. Specific activity increased from 16 AU/mg protein in the crude extract to 705 AU/mg protein in the final sample (1 AU = 1 mg maltose hydrate/min at 30°C). Two major protein bands, active in starch zymograms, were present at Rm 0.71 and 0.79 when the sample was examined by polyacrylamide gel electrophoresis (PAGE) on 7.5% gels. In addition, several minor proteins that had α-amylase activity were also present. Molecular masses of the two major allozymes were estimated to be 57 and 55 kDa under dissociating conditions. Isoelectric points of the allozymes were at pH 3.4 and 3.5. The amylases were most active at pH 7 and the presence of 20 mM NaCl resulted in a 10.7-fold increase in Vmax. Km for soluble starch was 0.127%.Saline extracts of wheat (“Florida 302”) were 2- and 3-fold more inhibitory on a weight basis towards the amylases from R. dominica than were extracts prepared from two cultivars of triticale, “Morrison” and “CT-4161”, respectively. Interaction of purified α-amylase inhibitors from wheat, inhibitor-0.28 and a sample of the inhibitor-0.19 family of isoinhibitors, with the α-amylases from R. dominica was studied. Complex formation between the amylases and inhibitor-0.28 was demonstrated by PAGE, although the protein-protein complexes that formed were not completely stable during electrophoresis. Ki values were estimated to be 2.6 nM for inhibitor-0.28 and 2.9 nM for inhibitor-0.19. Binding of these inhibitors to α-amylases from R. dominica was not as tight compared with the interaction of these inhibitors with amylases from Sitophilus weevils and Tenebrio molitor.</div>","PeriodicalId":13955,"journal":{"name":"Insect Biochemistry","volume":"21 3","pages":"Pages 303-311"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-1790(91)90020-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90302818","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}

引用次数: 70

Characterization of acetyl-CoA: Ecdysone 3-acetyltransferase in Schistocerca gregaria larvae 格氏血吸虫幼虫乙酰辅酶a:蜕皮酮3-乙酰转移酶的鉴定

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90030-I

Mohamed Kabbouh, Huw H. Rees

{"title":"Characterization of acetyl-CoA: Ecdysone 3-acetyltransferase in Schistocerca gregaria larvae","authors":"Mohamed Kabbouh, Huw H. Rees","doi":"10.1016/0020-1790(91)90030-I","DOIUrl":"10.1016/0020-1790(91)90030-I","url":null,"abstract":"<div>Characterization of the acetyltransferase (acetyl-CoA: ecdysone 3-acetyltransferase) which catalyzes the conversion of ecdysone into ecdysone 3-acetate was carried out in gastric caecae of day 7 last instar larvae of Schistocerca gregaria. This enzyme is one of the enzymic systems involved in the inactivation of ecdysteroids. The acetyltransferase exhibited a microsomal subcellular localization, an apparent Km for ecdysone of 71 μM, a maximal specific activity of 7.2 nmol/min/mg of protein and was inhibited competitively in the presence of 20-hydroxyecdysone with Ki = 68.8 μM. The enzyme required acetyl-CoA as co-substrate for its activity, the apparent Km for acetyl-CoA being 47.2 μM. Acetic acid could not replace acetyl-CoA as the co-substrate, indicating that the enzyme is an acetyl-CoA: ecdysone acetyltransferase and not a hydrolase. Similarly, esterification of ecdysone was not observed when long-chain fatty acyl-CoA derivatives were substituted as co-substrates. The reaction was linear for 20 min and with protein concentration up to 0.8 mg/ml.The formation of 20-hydroxyecdysone 3-acetate has been demonstrated in the same microsomal fraction and required also acetyl-CoA as co-substrate. The apparent Km of the acetyltransferase for 20-hydroxyecdysone was 53.5 μM, revealing that the enzyme had a somewhat stronger affinity for 20-hydroxyecdysone than for ecdysone.</div>","PeriodicalId":13955,"journal":{"name":"Insect Biochemistry","volume":"21 6","pages":"Pages 607-613"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-1790(91)90030-I","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76625563","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}

引用次数: 5

A larval serum protein of the silkworm, Bombyx mori: cDNA sequence and developmental specificity of the transcript 家蚕幼虫血清蛋白:cDNA序列及转录物的发育特异性

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90114-T

Yoshihiro Fujiwara, Okitsugu Yamashita

引用次数: 7

Gut tract microorganisms supply the precursors for methyl-branched hydrocarbon biosynthesis in the termite, Zootermopsis nevadensis 肠道微生物为白蚁(zotermopsis nevadensis)的甲基支链烃生物合成提供前体

Insect Biochemistry Pub Date : 1991-01-01 DOI: 10.1016/0020-1790(91)90023-8

Lin Guo, David R. Quilici, Jody Chase, Gary J. Blomquist

{"title":"Gut tract microorganisms supply the precursors for methyl-branched hydrocarbon biosynthesis in the termite, Zootermopsis nevadensis","authors":"Lin Guo, David R. Quilici, Jody Chase, Gary J. Blomquist","doi":"10.1016/0020-1790(91)90023-8","DOIUrl":"10.1016/0020-1790(91)90023-8","url":null,"abstract":"<div>In vivo and in vitro experiments were performed to examine the role of succinate and other potential precursors of the methylmalonyl-CoA used for methyl-branched hydrocarbon biosynthesis in the termite Zootermopsis nevadensis. The in vivo incorporation of [1,4-14C]succinate and [2,3-14C]succinate into hydrocarbon confirmed that succinate is a direct precursor to the methyl branch unit. The other likely precursors, the branched chain amino acids valine and isoleucine, were not efficiently incorporated into hydrocarbon. Carbon-13 NMR showed that one of the labeled carbons of [1,4-13C]succinate labeled position 6 of 5-methylalkanes and positions 6 and 18 of 5,17-dimethylalkanes, indicating that succinate, as a methylmalonyl-CoA unit, was incorporated as the third unit to form 5-methylheneicosane and as both the third and ninth units to form 5,17-dimethylheneicosane. Analysis of organic acids after the in vivo metabolism of [2,3-14C]succinate showed that succinate was converted to propionate and methylmalonate. Labeled succinate injected into the hemolymph was readily taken up by the gut tract. Isolated gut tissue efficiently converted succinate to acetate and propionate, both of which were released into the incubation media. Mitochondria from termite tissue (minus gut tract) converted succinate to methylmalonate and propionate only in the presence of malonic acid, an inhibitor of succinate dehydrogenase. The results of these studies show that while termite mitochondria are able to convert succinate to propionate and methylmalonate, most of the propionate used for methyl-branched hydrocarbon biosynthesis is produced by gut tract microorganisms. The propionate is then presumably transported through the hemolymph to epidermal cells for use in methyl-branched hydrocarbon biosynthesis.</div>","PeriodicalId":13955,"journal":{"name":"Insect Biochemistry","volume":"21 3","pages":"Pages 327-333"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-1790(91)90023-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86048579","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}

引用次数: 27