摘要:

AbstractFrom a medium in which Daudi cells had been grown, we isolated by HPLC a protein that caused ovarian abnormalities in adult females ofDrosophila melanogasterwhen injected into preblastoderm embryos. This protein, whose apparent Mris between 30,000 and 50,000, was found to be a moderately polar compound which is heat stable and whose activity is destroyed by acidification. The protein is characteristic of medium conditioned from Daudi cells. © 1992 Wiley‐Liss, I

ISSN:0739-4462    

DOI:10.1002/arch.940210202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe 80,000g supernatant o larval midgut homogenates of the tobacco hornworm,Manduca sexta, was fractionated by affinity chromatography on Blue Sepharose CL‐6B and by anion exchange chromatography on Q Sepharose. Both methods resolved one major 3‐oxoecdysteroid 3α‐reductase and three major 3‐oxoecdysteroid 3β‐reductases. The 3β‐reducates reacted only with BADPH as cosubstrate. The 3α‐reductase was active with both NADPH and NADH, and the NADPH/NADH activity ratio increased with the NaCl concentration (0–0.5 M) in the incubation mixtures. The 3‐α‐reductase and one of the 3‐β‐reductases showed very similar chromatographic properties, and their isoelectric points were 5.2 and 5.8, respect

ISSN:0739-4462    

DOI:10.1002/arch.940210203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractPolar and neutral lipids and their constitutive fatty acids were quantified in the pea aphid,Acyrthosiphon pisum(Harris), grown on host plant or on a lipid free artificial diet. The results were compared to determine if lipids were involved in the suitability of the diet for continuous rearing of thisA. pisumbiotype. For apterous adults grown on plants, the lipids were characterized by a low amount of neutral lipids (2.5% weight/fresh weight) almost entirely (96.4%) composed of hexanoyl and sorboyl dimyristin. These storage lipids were higher in the alatae (3.8%), probably correlated with potential flight activity. The phospholipid amounts were identical in these two morphs (1.3–1.4% weight/fresh weight), comprised mainly of phosphatidylethanolamines (52%) and phosphatidylcholines (40.6%). These phospholipids contained a still unidentified fatty acid, with a retention time close to that of linolenic acid and synthesized by the aphid or its bacterial symbionts (not found in plants). The apterous adult aphids reared on an artificial diet showed an accumulation of neutral lipids (8.9% for the first generation); this increase was shown to be slightly greater for the hexanoyl and sorboyl triglycerides. In contrast, the phospholipids decreased in aphids reared on an artificial diet (1.1% and 0.9%, respectively, for first and second generation), correlated with a phospholipid fatty acid profile significantly deficient in C18:3 and in the unidentified peculiar fatty acid. These phospholipids are essential components of biological membranes and a diet‐driven deficient synthesis in some of their components may result in the observed symptoms. © 1992 Wiley‐Lis

ISSN:0739-4462    

DOI:10.1002/arch.940210204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe effects of RH 5849 on the larval molt and larval‐pupal metamorphosis inSpodoptera littoralis(Boisd.) were examined. Application of RH 5849 to newly ecdysed 3rd and 6th (last) instar larvae induced a larval molt within the first day after application. Symptoms included cessation of feeding and larval weight, extrusion of gut, loss of hemolymph, and a developmentally abnormal and subsequent lethal larval ecdysis. Treated larvae died shortly afterwards. Treated 6th instar larvae, which did not appear to be affected before pupation, showed an abnormal and lethal pupation process.Differences in the protein pattern of the cuticle between treated vs. untreated 6th instar larvae, demonstrated by using PAGE, indicated that in the newly induced larval cuticle some proteins were missing or expressed with less intensity. The lack of several bands in the pattern of cuticular and hemolymph proteins of treated vs. untreated 6th instar larvae, probably from proteins specific for the pupal instar, is suggested as a cause of unsuccessful pupation in the treatment. © 1992 Wiley‐Liss,

ISSN:0739-4462    

DOI:10.1002/arch.940210205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractActivation and inactivation of fat body glycogen phosphorylase was investigated in ligated abdomens of larvalManduca sextaand in vitro. After maximal activation throughManducaadipokinetic hormone (AKH) or chilling, inactivation of glycogen phosphorylase commenced as soon as the stimulus for the activation was removed indicating that the enzyme system in the fat body is fine‐tuned to low phosphorylase activities which is necessary to allow glycogen synthesis. In intact ligated abdomens phosphorylase can be activated repeatedly by either stimulus showing that the fat body system does not lose its responsiveness. It was impossible to achieve complete conversion of the inactive form of phosphorylase into the active form even after administration of AKH and simultaneous chilling. © 1992 Wiley‐Liss,

ISSN:0739-4462    

DOI:10.1002/arch.940210206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA peptidylglycine α‐amidating monooxygenase (PAM) has been characterized in the tobacco hornwormManduca sexta. Although such enzymes have been well studied in vertebrates, their presence in invertebrates has not been reported. PAM activity was measured in several insect tissues. The highest specific activity was found in the brain. In this organ, PAM activity was high during the larval stages, but low at the end of metamorphosis. Copper, oxygen, and ascorbate were required for activity. Evidence that 2, 4, 5‐trihydroxyphenylalanine may be involved in PAM activity is presented. © 1992 Wiley‐Li

ISSN:0739-4462    

DOI:10.1002/arch.940210207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractRegulation of ecdysteroid production in lepidopteran prepupae was studied using a parasitic wasp (C. nearcurvimaculatus) which specifically suppresses host prepupal ecdysteroid production after the induction of precocious host metamorphosis. At the developmental stage at which the hemolymph of the unparasitized metamorphosing host has its maximum titer of prepupal ecdysteroids, the hemolymph of 4th instar “truly parasitized” hosts (hosts with a surviving endoparasite) had a strongly reduced ecdysteroid titer. However, during the photophase about 12 h later, just prior to emergence of the parasite larva, an ecdysteroid peak was observed in the host hemolymph. Fourth instar pseudoparasitized prepupal hosts (in which the endoparasite was not present or died early in development) exhibited a sustained suppression in the hemolymph ecdysteroid titer. Small 5th instar pseudoparasitized hosts, which normally would molt to a 6th instar prior to metamorphosis, but which precociously attained the prepupal stage, also had a strongly reduced ecdysteroid titer. The late increase observed in truly parasitized hosts could be completely prevented by surgical removal of the parasite 24 h earlier, resulting in a titer similar to that in pseudoparasitized hosts. HPLC analysis of ecdysteroids in normal, truly parasitized, and 4th or 5th instar pseudoparasitized prepupae showed that both ecdysone and 20‐OH ecdysoneAbbreviations used: 20‐OH ecdysone = 20‐hydroxyecdysone; 20, 26‐OH ecdysone = 20, 26 dihydroxyecdysone; PTTH = prothoracicotropic hormone.were suppressed in truly and pseudoparasitized prepupae, with ecdysteroid levels being lowest in pseudoparasitized hosts. These data, and those of Brown and Reed‐Larsen (Biol Contr 1, 136[1992]), showing endoparasite secretion of ecdysteroids just prior to its emergence from the host, strongly indicate that: (1) the prepupal peak in truly parasitized hosts originates from the endoparasite, and (2) the low level of ecdysteroids in pseudoparasitized hosts results from the host's intrinsic inability to express a normal level of prepupal ecdysteroid titer. While precocious 4th or 5th instar prepupae of similar size had similarly suppressed ecdysteroid titers, smaller 4th instar prepupae had a lower ecdysteroid titer than larger, precocious 5th instar prepupae. Rare 5th instar pseudoparasitized prepupae that were of nearly normal size showed a prepupal ecdysteroid titer distinctly greater than those of the usual smaller, precocious 5th instar prepupae. The data suggest that the competence of the host to express a normal hemolymph titer of prepupal ecdysteroids is more closely correlated with the size of the prepupae than with the instar attained. © 1992 W

ISSN:0739-4462    

DOI:10.1002/arch.940210208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940210209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940210201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY