摘要:

AbstractAcromelic acid, a naturally occurring kainoid, isolated from the mushroomClitocybe acromelalga, is a weak displacer of [3H]L‐glutamate binding to cockroach (Periplaneta americana) nerve cord membranes. Acromelic acid (1 mM) displaces ∼︁60% of specifically bound [3H]L‐glutamate. When applied by bath perfusion to the cell body membrane of the cockroach fast coxal depressor motor neurone, acromelic acid generated slow, prolonged, dose‐dependent depolarizations at concentrations of 0.3 μM and above. Thus acromelic acid is among the most potent of the excitatory amino acids tested to date on insect neurones. © 1994 Wile

ISSN:0739-4462    

DOI:10.1002/arch.940250202

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe excretion, retention, and tissue distribution of [3H]‐dihydroazadirachtin was investigated in the variegated cutworm,Peridroma saucia(Noctuidae). The candidate compound was rapidly cleared from the hemolymph following either oral exposure or topical administration, with maximum concentrations at 6 h post‐treatment and peak appearance of label in the frass at 12 h. However, approximately 45 and 55% of the labelled material was retained in the body at 72 h in respective treatments. Major depots for retained radioactivity were the gut (24% of the administered oral dose, 18.8% of the administered topical dose) and integument (12.2% of the oral dose and 30.7% of the topical dose). The variation in tissue distribution of dihydroazadirachtin with respect to the mode of application is discussed. A single polar metabolite fraction was obtained from the frass of dihydroazadirachtin‐fed larvae. The physiological and behavioral effects of 22,23‐dihydroazadirachtin and azadirachtin are quantitatively similar. © 1994 Wiley

ISSN:0739-4462    

DOI:10.1002/arch.940250203

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

年代:1994

数据来源: WILEY

摘要:

AbstractDuring vitellogenesis the transport of yolk precursor proteins, the vitellogenins (VTG), from the hemolymph into the oocyte is achieved by receptor‐mediated endocytosis. Recently the receptor for the VTG ofLocusta migratoriahas been isolated. Now a new protocol has been developed for the purification of the VTG receptor of this locust from ovarian membranes. By CHAPS solubilization of the membranes followed by ion exchange and immunoaffinity chromatography, a 100‐fold purification of the VTG receptor was achieved. The amino acid composition of the receptor protein has been determined. However, first attempts to sequence the receptor failed due to the N‐terminal blocking of the molecule. With the same methods the VTG receptor of another locust,Schistocerca gregaria, has been isolated, purified, and characterized. This receptor has an apparent Mrof 186 kDa under nonreducing conditions. It recognizesL. migratoriaVTG and vice versa. However, in cross‐competition experiments in which theSchistocercaVTG competed withLocustaVTG for binding to theLocustaVTG receptor, theSchistocercaVTG was less efficient. Furthermore, the VTG receptor proteins ofS. gregariaandL. migratoriaare immunologically related as revealed by Western blotting with anti‐LocustaVTG receptor antibodies. It appears that important structural elements required for efficient and specific endocytosis of VTG have been conserved. © 1994 Wiley

ISSN:0739-4462    

DOI:10.1002/arch.940250204

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

年代:1994

数据来源: WILEY

摘要:

AbstractAn imidazole compound (KK‐42), a potent inhibitor of ecdysone synthesis, was applied to the female pharate adult of the silkworm,Bombyx mori, to control ecdysteroid accumulation in developing ovaries and mature eggs. KK‐42 applied on day 2 or later completely suppressed an increase in ecdysteroid content in developing ovaries. The inhibitory action of KK‐42 was restricted to vitellogenic follicles, i.e., those in which active ecdysteroid synthesis is occurring. Ecdysteroid content in the mature eggs of moths remained at the level accumulated in ovaries before KK‐42 application. Thus, KK‐42 was shown to be a novel agent to suppress the ecdysteroid accumulation in eggs. Eggs containing different amounts of ecdysteroids showed different levels of embryonic development. About 80% of the eggs which contained less than 10 ng free ecdysteroids/g eggs were not fertilized. More than 80% of the eggs containing less than 40 ng/g eggs of free ecdysteroids initiated embryogenesis but failed to hatch. Larvae hatched from almost all eggs which accumulated free ecdysteroids of more than 150 ng/g. Thus, maternal ecdysteroids appear to be required at different titers for fertilization, embryogenesis, and hatching of the silkworm larvae. © 1994 Wiley

ISSN:0739-4462    

DOI:10.1002/arch.940250205

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

年代:1994

数据来源: WILEY

摘要:

AbstractA riboflavin‐binding hexamerin isolated from pupal hemolymph ofHyalophora cecropiahas a native Mrof 510,000, subunit Mrof 85,000, and a 5% carbohydrate content. An intrachain cross‐link was confirmed in protease limit digests. Ellman titration confirmed the presence of a sulfhydryl group, which is needed for this linkage. Though Cu2+is known to promote the linkage, heavy metals were not detected in the isolate. Heat denaturation released ligand with the absorbency, fluorescence spectra, and chromatographic behavior of riboflavin. Binding resulted in substantial quenching of the fluorescence of both the isoalloxazine in riboflavin and of aromatic groups in the apoprotein. Kinetic analysis indicated a KDof 2.5 × 10−7M for riboflavin, 1.3 × 10−7M for lumiflavin, and greater than 1 × 10−6M for FMN and FAD. Over four moles of flavin were bound per mole of hexamerin. The amount of riboflavin in pupal hemolymph is sufficient to occupy only 2–3 of these sites. Riboflavin is also associated with lipophorin and vitellogenin, but the molar ratios after protein isolation were low. On a standard laboratory diet, riboflavin is in great excess, but most of it is apparently excreted before the apoprotein first appears in the hemolymph, just before wandering. The concentration of riboflavin‐binding hexamerin rises to 15–30 mg/ml in pupae; relative to other hexamerins, very little is stored in the fat body. All of the apoprotein and 75% of riboflavin disappear from the hemolymph during adult development. An amount of flavin at least equal to that stored in pupal hemolymph is transferred to the eggs formed during this period. © 1

ISSN:0739-4462    

DOI:10.1002/arch.940250206

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe midgut proteinase activities were characterized from the keratinolytic larvae of two lepidopterans,Hofmannophila pseudospretella(Stainton) (Oecophoridae) andTineola bisselliella(Hummel) (Tineidae), and one coleopteran,Anthrenocerus australis(Hope) (Dermestidae). The major endopeptidase activities, characterized using specific enzyme inhibitors, were serine proteinases with hydrolytic activity against N‐benzoyl‐DL‐arginine‐p‐nitroanilide and against N‐succinyl‐L‐alanyl‐L‐alanyl‐L‐prolyl‐L‐leucine‐p‐nitroanilide. No significant levels of metalloendopeptidase or cysteine endopeptidase activities were detected. Aminopeptidase activity was present in all larvae. The enzyme levels and properties of the two moth larvae were similar to each other and to those of phytophagous lepidopteran larvae but different from those of the beetle larva. Whereas only a limited number of serine proteinase inhibitors inhibited the midgut proteolysis of the lepidopteran larvae, most inhibitors inhibited the midgut proteolysis of the beetl

ISSN:0739-4462    

DOI:10.1002/arch.940250207

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

年代:1994

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940250208

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

年代:1994

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940250201

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

年代:1994

数据来源: WILEY