摘要:

AbstractResistance to the organophosphate insecticide, malathion, in a strain ofCulex tarsalismosquitoes is due to increased activity of a malathion carboxylesterase (MCE). To determine whether resistance was due to a qualitative or quantitative change in the MCE, the enzyme was purified from both malathion‐resistant and ‐susceptible mosquitoes. Enzyme kinetic measurements revealed that the two strains have one MCE in common, but resistant mosquitoes also have a unique MCE which hydrolyses malathion 18 times faster. Interestingly, this MCE does not hydrolyse α‐naphthyl acetate, a substrate commonly used to detect increased levels of esterases in other organophosphate‐resistant insects. Unlike the over‐produced esterase of some related mosquito species, each MCE inC. tarsalisaccounts for only a small fraction (0.015%) of the total extractable protein in either strain. Therefore, resistance in these insects is due to the presence of a qualitatively different enzyme, and not to a quantitative increase of a non‐specific esterase. This study therefore demonstrates that the underlying biochemical mechanisms of insecticide resistance in one insect cannot necessarily be predicted from those of another, even closely related species. © 1995 Wi

ISSN:0739-4462    

DOI:10.1002/arch.940290402

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

年代:1995

数据来源: WILEY

摘要:

AbstractFeeding starved adult migratory locusts,Locusta migratoria, caused decreases of hemolymph lipid concentrations and of the percentage of active fat body glycogen phosphorylase which suggested that a molecule(s) from the neurosecretory system or the midgut may have been released to regulate metabolism. Fat body phosphorylase was also inactivated after insects were transferred from 0 to 25 ° C. In adults with elevated hemolymph lipid levels after the injection of small doses of corpus cardiacum extract (CC), feeding did not induce a decrease in hemolymph lipid concentrations. It appears that the processes initiated by feeding could not override the effects of the continued presence of adipokinetic hormone(s) (AKHs) in the hemolymph or their long‐term effects.Aqueous, methanolic, or ethanolic extracts of brains or storage lobes (SL) of fed locust CC did not lead to decreases of hemolymph lipid concentrations. Bovine insulin was equally inactive when tested at doses which were previously reported to reduce lipid levels. Fractions of ethanolic brain extracts from 3‐day‐starved males collected after high‐performance size‐exclusion chromatography, however, produced hypoglycemic effects in fed males. Two biologically active fractions were found, one with high (≥ 10 kDa) and one with low molecular weight (approximately 1 kDa). © 1995 Wi

ISSN:0739-4462    

DOI:10.1002/arch.940290403

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe production and uptake of the follicular epithelium yolk protein (FEYP) is terminated coincident with the initiation of vitelline membrane synthesis in follicles of the Indianmeal moth,Plodia interpunctella(Hübner). This was determined by visualizing the cytolocalization of the FEYP subunits YP2 and YP4 using antisera to immunolabel ultrathin sections or whole‐mounted ovaries. Both subunits of FEYP were detectable in the Golgi apparatus and associated secretory granules of the follicular epithelial cells (FC) in vitellogenic follicles. Before the follicles entered the terminal growth phase, the oocytes began production of specialized organelles, late yolk spheres. Following the appearance of late yolk spheres in the oocyte, the FC initiated the production of vitelline membrane proteins and the rapid clearance of YP2 from their cytoplasm. No YP2 was detected in the Golgi apparatus or in the secretory granules of FC from follicles in terminal growth phase, although YP4 was detected in these organelles. The vitelline membrane of follicles in termal growth phase was a bilayered structure with an electron‐dense layer of vitelline membrane proteins that originated in the FC and an electron‐translucent layer containing yolk proteins. During this period, late yolk spheres were observed fused with the oolemma exposing and possibly releasing their contents to the electron‐translucent layer of the vitelline membrane. From this evidence, we suggest that during termination of vitellogenesis, the oocyte and FC work in concert to end uptake of yolk proteins and begin the synthesis of egg membranes, and that the oocyte contributes to the production of vitelline membrane by the release of previously sequestered yolk proteins. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States

ISSN:0739-4462    

DOI:10.1002/arch.940290404

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

年代:1995

数据来源: WILEY

摘要:

AbstractAn N‐terminal amino acid sequence of a 16.9 kDa hemolymph polypeptide, “Vesicle Promoting Factor” (VPF) fromTrichoplusia ni, revealed a high sequence homology (70%) withManduca sextaapolipophorin‐III. A polyclonal antibody developed against VPF, however, was not immunoreactive with either purifiedM. sextaorT. niapolipophorin‐III. Immunoblots of tissue homogenates ofT. niindicated that VPF was present in imaginal wing discs, central nervous system (CNS), silk glands, midgut and hemocytes from fifth instar larvae, and also in the IAL‐TND1 cell line which can grow as either fluid‐filled multicellular vesicles or multicellular aggregates. VPF was also detected immunologically in the hemolymph of adults ofT. ni, and in hemolymph of adults and larvae ofGalleria mellonellaandHeliothis virescens. Testes, midgut, hemocytes, and wing discs, but not Malpighian tubules, ofT. nireleased VPF into tissue culture medium during a 3 h incubation period. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United S

ISSN:0739-4462    

DOI:10.1002/arch.940290405

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

年代:1995

数据来源: WILEY

摘要:

AbstractTwo peptides related to locust adipokinetic hormone and crustacean red pigment concentrating hormone were isolated by high performance liquid chromatography from the cicadasCacama valavataandDiceroprocta semicincta. Both species have the same peptides. The structure of one of the peptides is pGlu‐Val‐Asn‐Phe‐Ser‐Pro‐Ser‐Trp‐Gly‐Asn‐amide. The mass spectrum, amino acid composition, and amino acid sequence of the other peptide suggest that it is almost identical to the first peptide. However, the exact nature of the difference between the two peptides could not be determined. ©

ISSN:0739-4462    

DOI:10.1002/arch.940290406

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

年代:1995

数据来源: WILEY

摘要:

AbstractMale black cutworm,Agrotis ipsilon(Hufnagel) moths, were attached to laboratory flight mills on the third night after emergence. Individuals were classified according to their longest uninterrupted flight during the night. There were not enough non‐fliers or trivial fliers (flight<1 h) to make meaningful comparisons, so only short‐fliers (flight ≥ 1 h but ≤ 5 h) and long‐fliers (flights ≥ 5 h) were further tested. After a day of rest, short‐ and long‐fliers were tethered to a stationary pin and forced to fly 0, 10, 20, 30, 60, 120, or 180 min, after which hemolymph was sampled and lipid and carbohydrate concentrations determined. Concentrations in samples taken at intervals after cessation of a 60‐min flight indicated that both energy sources were being utilized during flight. Neck‐ligation experiments indicated that a handling‐induced hyperlipemic response occurs 15 min after the beginning of the sampling procedure, and that the hormone triggering does not come from the head. Resting concentration of lipid in long‐fliers is about half that of short‐fliers, but it increases threefold in the first 20 min of flight, whereas that of short‐fliers remains unchanged. In‐flight lipid concentration in controls, which experienced their first and only flight on day 5, was greater than the concentration in both short‐ and long‐fliers. Between 10 and 20 min, carbohydrate concentrations decrease about twofold in long‐fliers but drop only slightly in short‐fliers. These data suggest that long‐fliers may have a lower basal metabolic rate and depend more on carbohydrate when at rest than short‐fliers and that long‐fliers may utilize more carbohydrate than lipid during the initial period of flight. In addition, previous flight on the flight mills has a greater influence on lipid mobilization and usage in short‐fliers than it does on long‐fliers. Patterns of lipid mobilization during flight seem to differ between migrant and non‐migrant species and to vary among migrants depending on the flight strategy used, but there are no major differences in patter

ISSN:0739-4462    

DOI:10.1002/arch.940290407

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

年代:1995

数据来源: WILEY

摘要:

AbstractIn the hemolymph ofMelanoplus sanguinipes, a high molecular weight juvenile hormone binding protein (JHBP) was identified by photoaffinity labelling and found to have a Mrof 480,000. The JHBP, purified using native gel electrophoresis followed by electroelution, has an equilibrium dissociation constant for JH III of 2.1 nM and preferentially binds JH III over JH I. Antibody raised against JHBP recognized only the 480,000 band. Under denaturing conditions the native JHBP gave a single band with a Mr78,000. The antibody against native JHBP recognized only the 78,000 protein in SDS‐treated hemolymph samples, indicating that JHBP is a hexamer in this species. The concentration of JHBP fluctuates in both the sexes during nymphal and adult development in parallel with total protein content of hemolymph. © 1995 Wiley‐Liss,

ISSN:0739-4462    

DOI:10.1002/arch.940290408

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

年代:1995

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940290409

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

年代:1995

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940290401

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

年代:1995

数据来源: WILEY