摘要:

AbstractThe yolk platelets fromRhodnius prolixus, a blood‐sucking bug, are composed mostly of vitellin and here are shown to contain at least two hydrolytic enzymes, a phosphatase and a cathepsin D‐like proteinase. Both the proteinase and the phosphatase have an acid pH optimum. No hydrolytic activity was observed under alkaline or neutral conditions. Among several proteinase inhibitors tested, only pepstatin could abolish vitellin breakdown in vitro. The proteinase appears to be bound to the yolk platelet membranes. The phosphatase activity, usingp‐nitrophenyl phosphate as substrate, was enhanced after disruption of the platelet membrane by Triton X‐100. This activity could be inhibited by tartrate but not byp‐cloromercuribenzoate. © 1992 Wiley

ISSN:0739-4462    

DOI:10.1002/arch.940210402

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

年代:1992

数据来源: WILEY

摘要:

AbstractMitochondrial DNA from the fall armyworm,Spodoptera frugiperda(J.E. Smith), was cloned and characterized using restriction enzyme mapping. Genome size is approximately 16.3 kilobase (Kb), consistent with that of most animals. Three fragments, 8.1 Kb, 6.2 Kb, and 2.0 Kb, were produced by digestion with restriction enzymeXbal and cloned into a pUC19 vector. Twenty‐nine restriction enzymes were used to generate a detailed physical restriction enzyme map of the three cloned fragments. These data represent the first detailed characterization of a lepidopteran mitochondrial genome. © 1992 Wiley‐Liss,

ISSN:0739-4462    

DOI:10.1002/arch.940210403

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

年代:1992

数据来源: WILEY

摘要:

AbstractCold hardiness in eggs (pharate first instar larvae) of the gypsy moth is not a component of the diapause program, but is acquired only after the pharate larvae have been chilled. The supercooling points of unchilled (25°C) and chilled (5°C) eggs are nearly the same (ca. −27°C), and chilling does not further elevate concentrations of glycerol, the major cryoprotectant, yet chilling at 5°C greatly increases the pharate larva's tolerance of −20°C. One conspicuous difference between the chilled and unchilled pharate larvae is their ability to express stress proteins. The most abundantly expressed stress protein, 75,000 Mr, was expressed more highly in chilled pharate larvae than in unchilled pharate larvae, both at high temperatures (>40°C) and in response to low temperature (−15°C). This correlation suggests a link between stress protein synthesis and the acquisition of cold tolerance. © 1992 Wi

ISSN:0739-4462    

DOI:10.1002/arch.940210404

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe results indicate that certain hemocyte proteins of the medfly,Ceratitis capitata, are responsible for the recognition of foreignness, since they are able to bind to the surface ofEscherichia coliin vitro. Furthermore, when theE. Coli‐hemocyte protein complex was incubated in the presence of tyrosine and phenoloxidase, the bacteria were immobilized, forming large aggregates. The formation of aggregates seems to be due to reactive tyrosine intermediate (quinone) generated by the action of phenoloxidase. © 1992 Wiley‐Liss,

ISSN:0739-4462    

DOI:10.1002/arch.940210405

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe actions of acetylcholine and cholinergic ligands have been studied using dorsal midline neurones from the metathoracic ganglion of the cockroachPeriplaneta americana. Both nicotine and oxotremorine depolarized dorsal midline neuronal cell bodies. Dose‐response curves for nicotine and oxotremorine saturated at different levels. Nicotine‐induced depolarizations were completely or partially blocked by mecamylamine, d‐tubocurarine, strychnine, and bicuculline, but were insensitive to α‐bungarotoxin (100 nM), atropine (100 μM), scopolamine (10 μM), and pirenzepine (50 μM). Following pretreatment with collagenase, the dorsal midline neurones were sensitive to high doses of α‐bungarotoxin (3 μM). Oxotremorine‐induced depolarizations were blocked by scopolamine (10 μM), atropine (100 μM), and pirenzepine (50 μM) and were insentive to mecamylamine (10 μM) and d‐tubocurarine (100 μM). The results indicate the coexistence of at least two distinct acetylcholine receptors on dorsal midline neuronal cell bodies in the cockroach metathoracic ganglion

ISSN:0739-4462    

DOI:10.1002/arch.940210406

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe effects of 5‐hydroxytryptamine (5‐HT), octopamine, and dopamine on adenylate cyclase activity were studied using fragmented hemocyte membranes of the American cockroach,Periplaneta americana. 5‐HT and octopamine increased cAMP production with maximal effects at 10 nM and 10 μM respectively. Dopamine did not affect adenylate cyclase activity. The effects of octopamine and 5‐HT are not additive, indicating that both are working through the same receptor. A pharmacological profile suggests that the receptor present on the cockroach hemocytes is more similar to a 5‐HT receptor than an octopamine receptor. Mammalian antagonists of 5‐HT‐receptors blocked the 5‐HT‐induced increase in cAMP production with the following order of potency: mianserin>ketanserin>spiperone>ICS 205,930. In phagocytosis assays using whole hemocytes, 5‐HT increases cAMP production above control levels at 0.25, 0.75, 15, and 65 min. Addition of Bt2cAMP at 0.1 mM inhibits phagocytosis whereas, at 10 nM, Bt2cAMP enhances phagocytosis. Imidazole at 0.1 mM also enhanced phagocytosis. A 5‐HT‐mediated elevation in cAMP production may result in either an activation or inhibition of phagocytic activities

ISSN:0739-4462    

DOI:10.1002/arch.940210407

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.940210408

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.940210401

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

年代:1992

数据来源: WILEY