摘要:

AbstractLow levels of lysozyme were found in the midgut epithelium of the tobacco hornworm,Manduca sexta, during the early part of the fifth larval stadium. This was observed in control insects as well as in bacterially challenged insects. No lysozyme was detected in the gut contents of either group of insects which were actively eating or in the early stages of metamorphosis. However, high levels of lysozyme activity were detected in homogenates of midgut tissue collected from insects later in the stadium. Immunocytochemical studies demonstrated that lysozyme accumulates in large apical vacuoles in regenerative cells of the midgut during the larval‐pupal molt. These cells, initially scattered basally throughout the larval midgut epithelium, multiply and form a continuous cell layer underneath the larval midgut cells. At the larval/pupal ecdysis the larval midgut epithelium is sloughed off and the regenerative cells, now forming the single cell layer of the midgut, release the contents of their vacuoles into the midgut lumen. This release results in high lysozyme activity in the lumen of the pupal midgut and is thought to confer protection from bacterial infection. This is the first indication that the lysozyme gene may be developmentally regulated in a specific tissue in the absence of a bacterial infectio

ISSN:0739-4462    

DOI:10.1002/arch.940170202

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

年代:1991

数据来源: WILEY

摘要:

AbstractHormonal control of the production of the main sex pheromone component, Z11‐hexadecenal (Z11‐16:Ald), of femaleHelicoverpa zeawas investigated using labeled precursors to monitor the pheromone biosynthetic pathway. The pathway originates with the biosynthesis of palmitic acid followed by δ11 desaturation to form the intermediate Z11‐16:Acid, which is then reduced to a primary alcohol and then oxidized to Z11‐16:Ald. Incubation of glands either in vivo or in an isolated gland culture with the deuterium labeled compounds, D3‐16:Acid or D9‐Z11‐16:Acid, yielded no differences in label incorporation into pheromone in the presence or absence of synthetic PBAN (Pheromone biosynthesis activity neuropeptide). However, unlabeled pheromone titers increased about tenfold above controls in the presence of PBAN in both in vivo and in vitro cultures. When isolated glands were incubated with [1‐14C]acetate, about a thirtyfold increase in the incorporation of radiolabel into Z11‐16:Ald above controls was observed in the presence of PBAN. Also, about a tenfold increase in incorporation was observed in saturated and monounstaturated fatty acids found in the gland upon stimulation with PBAN. These results indicate that the hormone PBAN controls pheromone biosynthesis inH. zeaby regulating a step in or prior to fatty

ISSN:0739-4462    

DOI:10.1002/arch.940170203

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

年代:1991

数据来源: WILEY

摘要:

AbstractExtracts of brains, subesophageal ganglia, Malpighian tubules, mandibular glands, proctodaea, salivary glands, testes, and fat body from mature fifth‐stage European corn borer larvae contain a 3‐oxoecdysteroid 3β‐reductase that converts 3‐dehydroecdysone to an RIA‐detectable ecdysteroid that has the same retention time (on HPLC and TLC) as ecdysone. Enzyme activity is destroyed by boiling, exposure to organic solvents, and treatment with trypsin. The reductase has a molecular weight in the range of 24–37 kD and is dependent upon the presence of NADPH for activity. Under the conditions utilized here, subesophageal ganglia, proctodaea, and brain extracts exhibited the highest specific activity; mandibular glands, testes, salivary glands, and Malpighian tubules had moderate specific activity; and fat body had the least. Based on total organ activity, however, fat body and salivary glands had the greates activity; testes, Malpighian tubules, mandibular glands, and proctodaeum had moderate activity; and brain and subesophageal ganglion h

ISSN:0739-4462    

DOI:10.1002/arch.940170204

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

年代:1991

数据来源: WILEY

摘要:

AbstractMuscarinic receptors in brain membranes from honey bees, houseflies, and the American cockroach were identified by their specific binding of the non‐selective muscarinic receptor antagonist [3H]quinuclidinyl benzilate ([3H]QNB) and the displacement of this binding by agonists as well as subtype‐selective antagonists, using filtration assays. The binding parameters, obtained from Scatchard analysis, indicated that insect muscarinic receptors, like those of mammalian brains, had high affinities for [3H]QNB (KD= 0.47 nM in honey bees, 0.17 nM in houseflies and 0.13 nM in the cockroach). However, the receptor concentration was low (108, 64.7, and 108 fmol/mg protein for the three species, respectively). The association and dissociation rates of [3H]QNB binding to honey bee brain membranes, sensitivity of [3H]QNB binding to muscarinic agonists, and high affinity for atropine were also features generally similar to muscarinic receptors of mammalian brains.In order to further characterize the three insect brain muscarinic receptors, the displacement of [3H]QNB binding by subtype‐selective antagonists was studied. The rank order of potency of pirenzepine (PZ), the M1selective antagonist 11‐((2‐((dimethylamino)‐methyl)1‐ piperidinyl)acetyl)‐5, 11‐dihydro‐6H‐pyrido(2,3‐b)‐(1,4)‐benzodiazepin‐6 one (AF‐DX 116), the M2‐selective antagonist, and 4‐DAMP (4‐diphenylacetoxy‐N‐methylpiperidine methiodide) the M3‐selective antagonist, was also the same as that of mammalian brains, i.e., 4‐DAMP>PZ>AF‐DX 116. The three insect brain receptors had 27–50‐fold lower affinity for PZ (Ki484–900 nM) than did the mammalian brain receptor (Ki16 nM), but similar to that reported for the muscarinic receptor subtype cloned fromDrosophila. Also, the affinity of insect receptors for 4‐DAMP (Ki18.9–56.6 nM) was much lower than that of the M3receptor, which predominates in rat submaxillary gland (Kiof 0.37 nM on [3H]QNB binding). These drug specificities of muscarinic receptors of brains from three insect species suggest that insect brains may be predominantly of a unique subtype that is close to, tho

ISSN:0739-4462    

DOI:10.1002/arch.940170205

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe hemolymph of each caste of the primitive dampwood termiteZootermopsis nevadensis(Isoptera, Termopsidae, Termopsinae) contains a high molecular mass lipoprotein which functions as a specific, high affinity carrier for juvenile hormone (JH) III, as detected by JH III‐displaceable covalent modification by the tritium‐labeled photoaffinity analog (10R)‐10, 11‐epoxyfarnesyl diazoacetate ([3H]EFDA). The Formosan termiteCoptotermes formosanus(Rhinotermitidae, Coptotermitinae) and Eastern subterranean termiteReticulitermes flavipes(Rhinotermitidae, Rhinotermitinae) possess analogous proteins. Variations among the major proteins and the JH‐binding lipoproteins are

ISSN:0739-4462    

DOI:10.1002/arch.940170206

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

年代:1991

数据来源: WILEY

摘要:

AbstractTwo analogues of aManduca sextaallatotropin (Mas‐AT) were synthesized. They correspond to the active fragment, amino acids 5–13, of the natural Mas‐AT with substitution of norleucine for methionine. ATANA has the structure Val‐Glu‐Nle‐Nle‐Thr‐Ala‐Arg‐Gly‐Phe‐NH2, ATAA is acetylated at the N‐terminus. Allatotropic potency was evaluated by measuring the in vitro rates of juvenile hormone (JH) biosynthesis in corpora allata (CA) ofM. sexta.At a concentration of 20 nM, ATANA and ATAA increased JH production in day 0, day 1, and day 3 adult female CA by a factor of 3–8. Larval CA were not affected. These results correspond to activities reported for the natural Mas‐AT. ATANA did not stimulate pharate adult female CA to produce JH. Stimulation of female CA with ATANA was reversed when the CA were transferred to fresh medium while stimulation with ATAA under the same condition persisted.Exogenous farnesoate was converted to JH‐III at a rate exceeding the highest ATANA‐stimulated rate. ATANA in addition to farnesoate did not increase JH‐III production, but increased JH‐II production in addition to the already high production rate for JH‐III. It is inferred that Mas‐AT stimulates a rate‐limiting enzyme in the biosynthesis of farnesoate and its homologues but

ISSN:0739-4462    

DOI:10.1002/arch.940170207

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

年代:1991

数据来源: WILEY

摘要:

AbstractVitellogenin has been identified in the antCamponotus festinatus, both in queens and workers. In the workers, it is already present before adult eclosion in low concentrations (<1 μg/μl hemolymph). Vitellogenin and vitellin are immunologically identical and are composed of a single type of apoprotein with an apparent Mr= 185,000. The molecular weight of the native molecules was estimated as ∼460,000 by pore limiting gradient electrophoresis. Vitellogenin was detected as a major protein in the hemolymph of young workers, both under queenright and queenless conditions. Thus, in spite of their sterility in the presence of the queen,C. festinatusworkers are able to synthetize vitellogenin which is identical both in size and immunologically to the queen vitellogenin. About 6–7 weeks after adult eclosion, however, vitellogenin was usually undetectable in the hemolymph of queenright workers, particularly the minor workers, while it constituted about 30% of total protein in queenless workers. Protein concentration in the hemolymph of queenless insects increased up to 20‐fold as compared to 1‐day‐old insects. Queenless workers also developed large amounts of perivisceral fat body, while queenright workers, particularly the minor workers, showed a dramatic fat body regression about 6 weeks afte

ISSN:0739-4462    

DOI:10.1002/arch.940170208

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

年代:1991

数据来源: WILEY

摘要:

AbstractOne membrane‐bound α‐glucosidase and two soluble α‐glucosidases were isolated from homogenates of the hind‐midgut, the main digestive region inMusca domesticalarvae. The membrane‐bound α‐glucosidase and the low‐Mr soluble α‐glucosidase hydrolyze maltopentaose better than maltose, maltotriose, and maltotetraose, the reverse being true for the high‐Mr soluble α‐glucosidase. A membrane‐bound glucoamylase previously described inMusca domesticamidgut was shown by gradient centrifugation and dialysis against EDTA to result from the combined action of an amylase and an α‐glucosidase. The determination of amylase, α‐glucosidases, soluble and membrane‐bound carboxypeptidase A, membrane‐bound aminopeptidase and dipeptidase along the tissue and luminal contents of the hind‐midgut is described. The data support a proposal concerned with how starch and protein are digested inMusca domesticalarval hind‐midguts and where and how midgut

ISSN:0739-4462    

DOI:10.1002/arch.940170209

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

年代:1991

数据来源: WILEY

摘要:

AbstractA novel hemolymph protein fromTenebrio molitorassociated with desiccation stress has been purified and characterized. The protein contains cysteine; it was labeled in vivo using [35S]‐cysteine, and the amino acid analysis showed a 4% cysteine content. In the native state dsp28 is a dimer with a single subunit Mrof 28,000. The synthesis of dsp28 and its concentration in larval hemolymph increase dramatically after desiccation. Dsp28 is a major component of total larval hemolymph protein representing 5% of total protein in control insects and up to 17% in desiccated larvae. The hemolymph of cold‐acclimated larvae also contains elevated levels of ds

ISSN:0739-4462    

DOI:10.1002/arch.940170210

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

年代:1991

数据来源: WILEY

摘要:

AbstractMated females of the tropical warehouse moth,Ephestia cautella, start laying eggs shortly after adult emergence. All eggs are laid within 4 days and the adult's total life span is 5 to 6 days. If mating is prevented, egg laying is drastically delayed and the life span is extended to approximately 10 to 11 days. Virgin females lay fewer eggs than mated insects. If the juvenile hormone analogue methoprene is applied topically (100 ng/pupa) 2 to 3 days prior to adult emergence, the number of eggs per virgin female increases and the life span is reduced, as compared with nontreated virgins, and reaches values similar to control (mated) females. Changs in the ecdysteroid titer of females are related to egg laying. The concentrations increase and reach a maximum before most of the eggs are laid. Accordingly, the peak maximum is delayed in virgins as compared with mated females. This delay is prevented after application of methoprene. Mated and virgin females have lower ecdysteroid levels than treated virgins. In contrast to mated females, males have much lower ecdysteroid levels throughout their adult life.

ISSN:0739-4462    

DOI:10.1002/arch.940170211

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

年代:1991

数据来源: WILEY