摘要:

AbstractCalyx fluid and venom from the braconid parasitoidMicroplitis demolitordifferentially affected the development ofPseudoplusia includensandHeliothis virescens. P. includensexhibited delays in larval development, supernumerary instars, and formed larval‐pupal intermediates when injected with 0.01–0.10 wasp equivalents of calyx fluid. In contrast,H. virescenswas relatively unaffected by calyx fluid regardless of dose. Venom did not affect the development of either host species, but appeared to synergize the activity of calyx fluid. This was particularly evident inH. virescens, where injection of 0.10–0.20 wasp equivalents of calyx fluid and venom induced the formation of a large number of intermediates while the same amount of calyx fluid did not. The particulate portion ofM. demolitorcalyx fluid was the only component that caused developmental delays and the formation of intermediates in both host species. Purified virus caused developmental alterations inP. includens, while trioxsalen treated calyx fluid did not affect development ofP. includensorH. virescens. These data suggest the requirement for venom in parasitism may differ between host species, and that dosage plays an important role in interpreting the interaction between calyx and venom compo

ISSN:0739-4462    

DOI:10.1002/arch.940180302

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

年代:1991

数据来源: WILEY

摘要:

Abstractγ ‐ Aminobutyric acid (GABA) receptors were examined in the cockroach central nervous system (CNS) using the single fiber‐oil gap method applied to an identified giant interneuron. Short‐lasting pressure application of 10 mM GABA developed a multiphasic response composed of a fast hyperpolarization followed by a transient depolarizing component and a stable hyperpolarization. This triphasic characteristic shape of the response was modified according to the dose of GABA injected or bath‐applied and to the precise localization of the injection within the dendritic area. The transient depolarizing phase showed a negative reversal potential of −70 mV. Both hyperpolarizing phases reversed at a more negative level ranging to −80 mV. A positive shift of these values was caused by a decrease in external chloride concentration. Bath‐application of 0.1 mM picrotoxin (Ptx) decreased the depolarizing phase which was progressively replaced by a stable hyperpolarization. The transient depolarizing component desensitized quickly and was the most sensitive phase to Ptx action. The Ptx‐resistant response reversed at a mean value of −100 mV close to the equilibrium potential for potassium ions (EK+), suggesting that it was generated by a K+‐channel coupled receptor. Although baclofen was unable to mimic the Ptx‐resistant GABA response, the compound CGA 147823, known to bind with a high specificity to vertebrate GABABreceptors, has been successfully used to reproduce the Ptx‐resistant GABA response. It is suggested that, in addition to GABA receptors linked to chloride channels, the insect CNS possesses GABA receptors sharing ionic characteristics of GABABreceptors especially those located in the vertebrate CNS, although they are

ISSN:0739-4462    

DOI:10.1002/arch.940180303

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

年代:1991

数据来源: WILEY

摘要:

AbstractLarval hemolymph tyrosinase activity inDrosophila melanogasterwas detected with high performance liquid chromatography with electrochemical detection. The enzyme hydroxylated L‐tyrosine, and oxidized the diphenol substrates L‐dopa and dopamine. In larvae of a selected immune‐reactive strain the rates of tyrosine hydroxylation, dopa oxidation, and dopamine oxidation were markedly increased during the early stages of melanotic encapsulation of the eggs of the parasitic waspLeptopilina boulardi. Tyrosinase activity was not modified in parasitized larvae of a selected susceptible strain ofD. melanogaster, in which hosts the parasitoids developed unmolested. During the same period of parasitization, the amount of free tyrosine in immune reactive larvae was approximately three times higher than in susceptible hosts. These data indicate that the tyrosinase system of the immune reactive strain is activated during parasitization, and this results in the synthesis of some precursors which ultimately produce a melanotic and sclerotic capsule around the eggs of the parasite. Based on known genetic information of the enzyme system inDrosophila, it appears that at least two genes may be involved in the activation process, one associated with the proenzyme for monophenol oxidase activity, and the second with the proenzyme for diphenol oxidase act

ISSN:0739-4462    

DOI:10.1002/arch.940180304

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

年代:1991

数据来源: WILEY

摘要:

AbstractA cell culture medium, IPL‐52B, was preconditioned with host fat body and two insect cell lines to determine if they would support embryonic development ofMicroplitis croceipesin vitro. The medium was preconditioned with the cell line IPL‐LdFB, derived from fat body of the gypsy moth,Lymantria dispar, cell line IAL‐TND1, derived from imaginal discs of the cabbage looper,Trichoplusia ni, and whole fat body tissue from hostHelicoverpa zea. A second cell culture medium, Excell 400, was preconditioned with only the cell line, IPL‐LdFB. Pregerm band eggs were dissected from third instar host larvae and incubated in the conditioned medium for 20 h. Newly laid parasitoid eggs did not develop in unconditioned IPL‐52B, but did develop to germ band stage in unconditioned Excell 400. The IPL‐52B medium conditioned with both cell lines induced germ band formation, but only theL. disparcell line (IPL‐LdFB) promoted significant development to eclosion comparable to host fat body tissue. Excell 400 medium preconditioned with the cell line, IPL‐LdFB also supported developm

ISSN:0739-4462    

DOI:10.1002/arch.940180305

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

年代:1991

数据来源: WILEY

摘要:

AbstractIn eggs of the cockroachBlattella germanica, vitellin (Vt) utilization by the embryo is initiated at day 4 postovulation by the proteolytic processing of its three subunits to a specific set of peptides. A report from our laboratory (Nordin et al.:Archives of Insect Biochemistry and Physiology 15:119, 1990) described a yolk proteinase, activated at days 3–4, which processes the Vt. Further investigation of this event has focused on the yolk granules. Granules from eggs 4–6 days postovulation contained a significant subpopulation which accumulated high concentrations of the dye acridine orange (AO), a fluorescent probe of vesicle acidification, while those from eggs 0–3 days postovulation did not. AO accumulation was caused by proton translocation and was not due to dye binding or a Donnan equilibrium. The temporal correlation of granule acidification with Vt processing suggests a role for this event in yolk proteinase activation inB. germanica. This hypothesis was supported by the finding that incubation of yolk from freshly ovulated eggs in vitro at pH of 5 and below resulted in Vt processsing. Yolk granules of the blowflyPhormia reginaalso became acidified but this occurred in the oocyte prior to egg depos

ISSN:0739-4462    

DOI:10.1002/arch.940180306

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

年代:1991

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940180307

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

年代:1991

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940180301

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

年代:1991

数据来源: WILEY