摘要:

AbstractThe venom thatChelonussp. nearcurvimaculatusinjects into each parasitizedTrichoplusia niegg is entirely injected within the first 8 s of the 19‐s oviposition period, before deposition of the parasitoid egg that is injected during the final 1‐2 s of the oviposition. The parasitization factor, causing precocious metamorphosis of the host, is injected after the venom, but before the parasite egg. The venom by itself does not cause developmental redirection of the host.Chelonusvenom proteins are very stable in the host egg during the first 2 days of egg development. Then, on the last day before hatching, they are rapidly degraded by the proteolytic enzymes appearing in 3‐day‐oldT. nieggs. Among those that degrade the venom proteins are serine‐type proteinases, and at least one seems to be a trypsin‐

ISSN:0739-4462    

DOI:10.1002/arch.940100102

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe catabolic fate of 3,4‐dihydroxyphenethyl alcohol (DHPA) and 3,4‐dihydroxyphenylethyl glycol (DHPG) in insect cuticle was determined for the first time using cuticular enzyme(s) fromSarcophaga bullataand compared with mushroom tyrosinase‐medicated oxidation. Mushroom tyrosinase converted both DHPA and DHPG to their corresponding quinone derivatives, while cuticular enzyme(s) partly converted DHPA to DHPG. Cuticular enzyme(s)‐mediated oxidation of DHPA also accompanied the covalent binding of DHPA to the cuticle. Cuticle‐DHPA adducts, upon pronase digestion, released peptides that had bound catechols. 3,4‐Dihydroxyphenyl‐acetaldehyde, the expected product of side chain desaturation of DHPA, was not formed at all. The presence of N‐acetylcysteine, a quinone trap, in the reaction mixture containing DHPA and cuticle resulted in the generation of DHPA‐quinone‐N‐acetylcysteine adduct and total inhibition of DHPG formation. The insect enzyme(s) converted DHPG to its quinone at high substrate concentration and to 2‐hydroxy‐3′,4′‐dihydroxyacetophenone at low concentration. They converted exogenously added DHPA‐quinone to DHPG, but acted sluggishly on DHPG‐quinone. These results are consistent with the enzymatic transformations of phenoloxidase‐generated quinones to quinone methides and subsequent nonenzymatic transformation of the latter to the observed products. Thus, quinone methide formation in insect cuticle seems to be caused by the combined action of two enzymes, phenoloxidase and quinone tautomerase, rather than the action of quinone methide‐generating phenoloxidase (Sugumaran: Arch Insect Biochem Physiol8, 73–88, 1988). It is proposed that DHPA and DHPG in combination can be used effectively to examine the participation of (1) quinone, (2) quinone methide, and (3) dehydro derivative intermediates in the metabolism of 4‐

ISSN:0739-4462    

DOI:10.1002/arch.940100103

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

年代:1989

数据来源: WILEY

摘要:

AbstractAnalyses using one‐dimensional sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) previously demonstrated that parasitization by the braconid waspCotesia congregatasignificantly alters the normal hemolymph polypeptide profile of hostManduca sextalarvae. In the present study two‐dimensional gel analyses corroborated our earlier findings and provided additional evidence that multiple parasitism‐specific polypeptides were induced, which varied according to the stage of development of the wasps. Parasitization additionally elicited changes in the total protein concentration detected in the blood. Initially an elevation was observed, with newly parasitized larvae exhibiting a twofold elevation in hemolymph protein concentration by 12–24 h postoviposition. In contrast, terminal‐stage hosts with second instar parasites had significantly less protein in the hemolymph, likely due to reduced growth and inhibition of arylphorin synthesis by the fat body during the final stages of parasitism. Comparison of the array of hemolymph polypeptides produced in unparasitized larvae injected with 106cells of the gram‐negative bacteriumEnterobacter cloacaewith those proteins induced by parasitization indicated the two classes are different. Our findings confirm that the hostresponse to parasitism is a specific one, and not mimicked by bacterial challenge. Duringshort‐term in vitro culture of wasp larvae dissected from the host hemocoel, several proteins were detected in the medium using SDS ‐ PAGE, with their appearance in vitro suggestive of secretion by the wasps in vivo. Moreover, hemolymph from the parasites had significant amounts of putative host proteins, including an arylphorin ‐ like polypeptide and a protein with a mobility similar to that of insecticyanin. Thus, a dynamic interchange of proteins may occur, with the parasites accumulating host proteins while simultaneously secreting a variety of factors i

ISSN:0739-4462    

DOI:10.1002/arch.940100104

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

年代:1989

数据来源: WILEY

摘要:

AbstractNADPH oxidase activity was measured in third to sixth instar gypsy moth larvae fed oak or pine foliage. Activity levels ranged from 400 to 1,900 pmol NADPH oxidized/min/mg microsomal protein, but enzyme activity was not correlated with host plant ingested. Similarly, activity levels in larvae fed diets containing inducers, such as the terpenoid α‐pinene or pentamethylbenzene, ranged from 700 to 1,500 pmol NADPH oxidized/min/mg protein, levels that were comparable to those measured for larvae fed control diets. O‐demethylase activity in older instar gypsy moth larvae fed pine averaged 109 pmolp‐nitrophenol/min/mg protein, and activity levels in those fed diet containing α‐pinene ranged from 22 to 55 pmol/min/mg protein. Although statistically significant, these induced O‐demethylase levels are well below those observed forHeliothis zealarvae. Our findings indicate that monooxygenases play a minor, if any, role in the ability of later instar gypsy moth larvae to develop successfully on p

ISSN:0739-4462    

DOI:10.1002/arch.940100105

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

年代:1989

数据来源: WILEY

摘要:

AbstractIn attempting to develop an octopamine (OA) receptor preparation with ready access to large amounts of tissue, we examined the binding of OA to membranes from the heads of white and red houseflies (Musca domesticaL.). Binding was dependent on the presence of L‐ascorbic acid in the medium. However, equilibrium was reached only over 24–36 h at 4°C and reversal of binding was also slow and incomplete. Scatchard analysis revealed at least two binding sites in the white‐eyed housefly. A high‐affinity site (Kd= 13.9 nM andBmax= 3.9 pmol/mg protein) was present, but the majority of the binding had low affinity (Kd= 1130 nM andBmax= 165 pmol/mg protein). Scatchard analysis revealed a low affinity in the red‐eyed housefly (Kd= 240 nM andBmax= 12 pmol/mg protein). Catecholamines were the best competitors for OA binding followed by phenolamines such as OA and synephrine. 5‐Hydroxytryptamine was less effective. Phentolamine and mianserin, which are good antagonists of the ability of OA to stimulate adenylate cyclase in housefly head membranes, and formamidine and imidazolines, which are potent partial agonists of this adenylate cyclase, were poor competitors of OA binding. The slow kinetics, low affinity, large amount, and unconventional pharmacological profile of this binding is not congruent with it being a neuroreceptor. When the brain was dissected free from the head, less than 10% of the total specific binding of OA was found in the brain membrane fraction. This suggests that most of the binding of OA may be to cuticular sites that possibly are associated with the metabolism of catecholamines in cuticular synthesis. Thus, binding studies made with labeled catecholamines and phenolamines on insect tissues containing significant cuticular elements should be interpreted

ISSN:0739-4462    

DOI:10.1002/arch.940100106

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

年代:1989

数据来源: WILEY

摘要:

AbstractPrevious attempts to shift the (Z)‐11‐/(E)‐11‐tetradecenyl acetate ratio of pheromone components in the redbanded leafroller moth (RBLR),Argyrotaenia velutinana, by several selection protocols showed that this ratio is strongly canalized. Analysis of the complete seven‐component blend, however, showed that a Geneva laboratory stock of RBLR had a lower percent (20%) of the E9–12:OAc minor component compared to the E11–14:OAc component than a population of RBLR from North Carolina (31%). Hybrid populations from these two cultures were used in a two‐way family truncation selection scheme in which families were selected for either the lowest (low line) or the highest (high line) ratio of E9–12:OAc/E11–14:OAc. After three generations of selection, the low line had 14% E9–12:OAc relative to E11–14:OAc and the high line had 42%. The selection pressure was removed in generations 4–9, and the low line remained unchanged at 14% E9–12:OAc; but in the high line, it drifted to 53%.Studies were conducted to estimate heritability and realized heritability. The realized heritability calculated for each generation of selection averaged 1.14 for the low line and 1.50 for the high line. These calculations, along with estimated heritability values of 0.416 and 0.644 for reciprocal crosses, indicate some plasticity in the E9–12:OAc/E11–14:OAc ratio. This ratio was positively correlated to the total amount of 12‐carbon components to 14‐carbon components, but was negatively correlated to the Z/E ratio of Δ11‐tetradecenylacetates.The results of two studies on the canalization of various components of the RBLR sex pheromone blend indicate that there is limited potential in this insect for manipulation

ISSN:0739-4462    

DOI:10.1002/arch.940100107

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

年代:1989

数据来源: WILEY

摘要:

AbstractTestes from late last stage larvae of the tobacco budworm,Heliothis virescens, were incubated with [3H]ecdysone and [3H]cholesterol. [3H]Ecdysone was converted to six other major ecdysteroids, identified by cochromatography in reverse‐phase high‐pressure liquid chromatography (RPHPLC); four of them were verified by normal‐phase HPLC. A highly polar fraction, moderately polar ecdysteroids (20,26‐dihydroxyecdysone, 3‐epi‐20‐hydroxyecdysone, and 20‐hydroxyecdysone) and low‐polarity ecdysteroids, including 2‐deoxyecdysone, were detected after incubation with [3H]ecdysone. Compounds that reacted positively to antibodies to progesterone and testosterone were detected in the low‐polarity fractions. Testes were incubated in fractions corresponding to each of the major ecdysteroid peaks derived from [3H]ecdysone metabolism. Although most of the radioactive ecdysteroid fractions were further metabolized to high‐ and low‐polarity endpoints, 88% of the [3H]20‐hydroxyecdysone peak apparently remained unmetabolized. 20‐Hydroxyecdysone may be the primary ecdysteroid product of testes ofH. virescens.[3H]Cholesterol was not metaboli

ISSN:0739-4462    

DOI:10.1002/arch.940100108

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

年代:1989

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940100101

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

年代:1989

数据来源: WILEY