摘要:

AbstractThe papers contained in this special issue ofArchives of Insect Biochemistry and Physiologyare published in connection with the symposium entitled “Physiological and Molecular Interactions Between Parasitoids and Their Hosts” held at the XIX International Congress of Entomology, Beijing, China. Speakers in the program discussed advances in the field and provided insight into future directions of study. As a preface to this special issue, we summarize the history of this field as reflected through the continuing series of symposia held in association with the International Congres

ISSN:0739-4462    

DOI:10.1002/arch.940260202

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe 33,000 Dalton venom protein ofChelonusnearcurvimaculatuswas characterized for structural properties of charge, quaternary associations, and relationship to polydnavirus encoded proteins. Homogenous isoforms of the protein were isolated from the venom by sequential steps of (1) microdissection, (2) separation based on charge (Mono‐Q column HPLC or narrow‐range electrofocusing), and (3) centrifugal filtration based on molecular weight using Centricon microconcentrators. The purified protein dimerized under native conditions, and this quaternary association became denaturation resistant under certain conditions. Chemical modification of lysine epsilon amino groups did not disrupt such dimerization. The cDNA for the protein did not possess high similarity to any sequence encoded in the polydnavirus, as indicated by results of Southern blotting, but does possess similarity in its repeats to the repeats of the immunologically protective surface glycoprotein ofLeishmania amazonensis. © 1994 Wiley‐Lis

ISSN:0739-4462    

DOI:10.1002/arch.940260203

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

年代:1994

数据来源: WILEY

摘要:

AbstractInvestigations were conducted to determine the titer of storage proteins in larvae of the cabbage looper,Trichoplusia ni(Hübner), that were parasitized by the ectoparasitoidEuplectrus comstockiiHoward (Hymenoptera: Eulophidae). A gradual increase was noted in the titer of the storage proteins present in the hemolymph of parasitized third and fourth instar larvae and in the hemolymph of isolated thoracic and abdominal tissues of fourth instar larvae. The final amount present in parasitized third and fourth instar larvae was similar to that found in nonparasitized fifth instar larvae. The stimulation of storage proteins in envenomed larvae demonstrates the ability (competence) of early larval stages to produce a gene product that normally occurs in the last larval stadium of the lepidopteran larval host. The gene expression necessary for storage protein production in isolated tissues may be altered by mechanisms separate from inherent developmental processes and the intact endocrine system. © 1994 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of Amer

ISSN:0739-4462    

DOI:10.1002/arch.940260204

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe braconid endoparasitoid,Cotesia (=Apanteles) kariyaiphysiologically influences its host,Pseudaletia separata, through three factors: polydnavirus, venom, and teratocytes. Inhibiting testis development of the host seems to be one factor that is important for successful development of the parasitoid. CkPV (polydnavirus ofCotesia kariyai)plus venom depressed testis development. Testes from unparasitized day 0 last instar transplanted into isolated abdomens increased in volume after stimulation with 20‐hydroxyecdysone (20HE). However, day 0 testis preincubated with CkPV plus venom for 6 h and then transplanted into an isolated abdomen did not respond to 20HE. Southern blot analysis indicated CkPV‐DNA hybridized to testes‐DNA from parasitized hosts, suggesting the possibility that CkPV is involved in suppression of testes growth. Binding assays using PNA indicated a 2‐fold increase in ecdysteroid receptor binding activity during the late stage of parasitism. The increase in receptor activity might be related to the maintenance of a low ecdysteroid titer in parasitized hosts due to a feedback response. © 1994 Wiley

ISSN:0739-4462    

DOI:10.1002/arch.940260205

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe venom ofMicroplitis demolitorconsists of a mixture of proteins. On native PAGE gels three major proteins designated a, b, and g were detected, while on SDS‐PAGE gels two major proteins of Mr64.5 and 30.8 kD and several minor proteins were detected. No proteins smaller than Mr30.8 kD were present. Murine monoclonal antibodies were generated against different venom components. Analysis by Western blot of venom proteins separated on native and SDS‐PAGE gels confirmed that antibodies from seven hybridoma lines recognized venom components. Two of the seven hybridoma lines reacted specifically with protein g on native PAGE gels and the Mr30.8 k protein on SDS‐PAGE gels, while four other lines cross‐reacted with these and other venom proteins. The final hybridoma line reacted with protein a when venom was separated on native PAGE gels and an array of proteins when venom was separated on SDS‐PAGE gels. Using an enzyme‐immunoassay and specific monoclonal antibodies,M. demolitorfemales were estimated to inject 0.02—0.05 venom gland reservoir equivalents into its host,Pseudoplusia includens, at oviposition. Venom proteins persisted in host hemolymph for 6—12 h before dropping to undetectable levels. © 1994

ISSN:0739-4462    

DOI:10.1002/arch.940260206

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

年代:1994

数据来源: WILEY

摘要:

AbstractVirus‐like particles (VLPs) that are bound to the egg surface of a parasitic waspVenturia canescensare void of nucleic acid and unable to infect host tissue but instead provide a passive protection against the host's immune recognition. To investigate evolutionary and functional properties ofVenturiaparticles, we isolated cDNAs coding for a VLP‐protein by screening an expression library of the wasp, using antibodies against purified VLPs. The corresponding coding DNA is present in the wasp genome as a single‐copy gene. © 1994 Wiley‐L

ISSN:0739-4462    

DOI:10.1002/arch.940260207

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

年代:1994

数据来源: WILEY

摘要:

AbstractShared epitopes among venom, ovarian, and viral proteins may indicate that related proteins have similar functional roles during parasitization ofHeliothis virescensbyCampoletis sonorensis. Venom and ovarian proteins are introduced directly into the hemolymph during parasitization where they may target hemocytes or other components of the immune system. Polydnavirus expression has been detected in hemocytes, fat body, and other tissues but has not been detected earlier than 4 h after parasitization. Therefore, effects on hemocytes at times earlier than 4 h may not be caused by polydnavirus proteins synthesized in the parasitized insect. Visualization of hemocyte F‐actin with fluorescently labeled phallicidin indicated that a dramatic alteration of plasmatocyte and granulocyte cytoskeletons occurred within 1.5 h after parasitization. The predominant non‐viral proteins in the ovary introduced during parasitization were immunologically related to venom and viral envelope proteins. These ovarian proteins persist in the hemolymph. Antisera to the ovarian proteins bound to granulocytes and to plasmatocytes to a lesser degree, suggesting that ovarian proteins may be involved in early suppression of the host's immune response after parasitization. © 1994 Wiley‐Lis

ISSN:0739-4462    

DOI:10.1002/arch.940260208

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe ovaries of endoparasitic species of braconid and ichneumonid wasps contain large numbers of polydnavirus (PDV) virions that replicate in specialized calyx cells of the ovaries and are injected into the host larva during parasitization. In the braconid waspCotesia congregatathat parasitizes the tobacco hornworm,Manduca sexta, the total amount of viral DNA present in the ovaries was determined to be 25–75 ng. Analysis of viral DNA on 0.4% agarose gels showed that the genome was comprised of 15–20 circles of double‐stranded DNA. SDS‐PAGE analyses showed that a large number (>30) of structural polypeptides were present in the virions, and analysis of the venom likewise showed that multiple components were present. The major size classes of venom proteins differed from those present in the PDV. However, Western blots using polyclonal PDV antibodies showed that some cross‐reacting PDV‐like proteins were present in the venom, perhaps explaining the mild PDV‐enhancing effect of the venom. Injection of PDV into unparasitized larvae provoked pronounced alterations in their growth, development, pigmentation, and hemolymph proteins. A densely staining band of hemolymph proteins of approximately 18–20 kD appeared in large amounts relative to other hemolymph proteins several days following injection of PDV; this band was undetectable in naturally parasitized larvae. Eggs which had been washed extensively to remove PDVs were encapsulated following injection, but development of the host still was disrupted, usually in the post‐wandering prepupal stage. Thus, neither the parasites nor their host survived, despite mobilization of an “effective” host response.

ISSN:0739-4462    

DOI:10.1002/arch.940260209

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

年代:1994

数据来源: WILEY

摘要:

AbstractBoth larvae and teratocytes liberated upon hatching from the eggs of the endoparasitoidCardiochiles nigricepsViereck were found to release proteins into their surrounding environment as they develop. Teratocytes were found to synthesize and release a number of proteins into culture media in which they were incubated. The proteins released differed among the different teratocyte ages. Larvae were also found to release proteins into the culture media in which they were incubated. Ligation of the head or anal vesicle altered the protein pattern found in the media. The results demonstrate that both larvae and the associated teratocytes release proteins that may have important functions in the parasitoidhost interaction. © 1994 Wiley‐Liss, I

ISSN:0739-4462    

DOI:10.1002/arch.940260210

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

年代:1994

数据来源: WILEY

摘要:

AbstractAll larval stages ofHeliothis virescens(F.) parasitized by the endophagous larval parasitoidCardiochiles nigricepsViereck, a braconid species belonging to the subfamily Microgasterinae, exhibit developmental arrest at last instar and fail to pupate. The major part of larval development of the parasitoid is synchronized with the arrested host last larval instar and the parasitoid first molt is never observed before the host attains the late digging stage. At this time, the total ecdysteroid titer of the hemolymph of parasitized hosts is very low and subsequently shows a slow and gradual increase, characterized by a low titer of 20‐hydroxyecdysone (20‐HE) associated with consistent amounts of inactive ecdysteroid polar metabolites. Juvenile hormone esterase (JHE) activity is high in both control and parasitized host larvae at the early digging stage of development, and juvenile hormone analogs (JHA) applied to parasitized host last instar larvae appear to suppress the parasitoid molt. Concurrent with these changes was an increase in the hemolymph titer of proteins which was maintained at a high level in parasitized larvae in contrast to the observed decrease in control larvae at the cell formation stage of development. Neck‐ligation of newly molted host 5th instar parasitized larvae, prior to both JHE release and the increase in protein titers, inhibited growth and molting of the parasitoid. In contrast, ligation after JHE release and with high hemolymph protein titers resulted in parasitoid molting and growth. These data suggest that the host ecdysteroid hormones are not directly involved in the regulation of the parasitoid molt, although high juvenile hormone (JH) levels probably prevent it. More likely, molting is triggered by other biochemical changes, such as proteins or other factors occurring in the hemolymph. Molting ofC. nigricepslarvae in vitro into an ecdysone‐free semidefined medium further supported the view that host ecdysone is not necessary for the molt. Teratocytes ofC. nigricepsseem to play an important role in the inactivation of 20‐HE through its conversion to inactive polar metabolites, and along with female calyx fluid and venom which depress the secretory activity of the host prothoracic glands, they are the most important sources of host regulatory factors. © 1994 Wiley

ISSN:0739-4462    

DOI:10.1002/arch.940260211

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

年代:1994

数据来源: WILEY