Phenoloxidase activity in the haemolymph of parasitized and unparasitized Heliothis virescens

Sroka, Paul; Vinson, S. Bradleigh

doi:10.1016/0020-1790(78)90051-3

Cited by 34 publications

(8 citation statements)

References 21 publications

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“…However, Smilowitz (1973) found new protein bands as well as denser protein bands on gels resulting from parasitization of cabbage looper by Hyposoter exiguae. Hence, the results from these studies provide a positive indication that the protein synthesis in the host body is induced by the parasitoid, presumably due to some substances injected by the parasitoid (Srodaka & Vinson, 1978).…”

Section: Discussionmentioning

confidence: 74%

The effects of parasitism by an encyrtid parasitoid, Anagyrus pseudococci on the survival, reproduction and physiological changes of the mealybug, Planococcus citri

Islam

Perera

Copland

1997

Entomologia Exp Applicata

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Survival, reproduction and some biochemical changes in the citrus mealybug, Planococcus citri (Risso) parasitized by the endoparasitoid, Anagyrus pseudococci (Girault) are reported. The parasitized younger mealybugs were more likely to die than be successfully parasitized. The mean duration (±SE) required for mortality other than mummification were 1.85 ± 0.06, 2.48 ± 0.14 and 2.89 ± 0.17 days for first, second and third instar P. citri respectively. Hosts parasitized in the first instar did not produce any mummies while the second and third instar nymphs and adult stages of the mealybugs were mummified on average 8 to 11 days after attack. Parasitization caused cessation of normal fecundity as well as induction of early egg maturation of the mealybugs. The mealybugs parasitized in the adult stage produced a few eggs but the fecundity of unparasitized mealybugs was about 40 fold higher than that of parasitized mature adults. Parasitized pre‐ovipositing and mature adults laid eggs within 24 h of attack. SDS‐PAGE analysis of the body content of the parasitized mealybugs after 24 h and 48 h of parasitization and before egg hatch revealed an increase in the concentration of some proteins. Response to wound reactions was not visible either as formation of extra protein bands or increased density of the existing bands. The possible effect of parasitism on the changes of the reproductive physiology of the host is discussed.

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Section: Discussionmentioning

confidence: 74%

The effects of parasitism by an encyrtid parasitoid, Anagyrus pseudococci on the survival, reproduction and physiological changes of the mealybug, Planococcus citri

Islam

Perera

Copland

1997

Entomologia Exp Applicata

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“…Although inhibition of phenoloxidase activity may be important in evading the immune system, the evidence is not convincing. Sroka and Vinson [188] could not detect any early changes in phenoloxidase activity after parasitism with three different species although a decrease in melanin production occurred in the host later in the parasitoid's development. These authors also noted that phenoloxidase-related changes often occurred several days after the vulnerable period of the parasitoid, several days after egg hatch.…”

Section: Suppressionmentioning

confidence: 94%

How parasitoids deal with the immune system of their host: An overview

Vinson

1990

Arch Insect Biochem Physiol

199

110

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Insects have evolved many mechanisms that reduce their potential for serving as hosts for entomophagous species. Some of these mechanisms involve escape, mimicry, and repellancy, which are effective defense mechanisms against both predators and parasitoids. But, insects have a second line of defense against parasitoids and parasites. These may include repellancy and a cuticular barrier to invasion but they include several internal defenses that are collectively referred to as immune mechanisms. The current understanding of insect immunity is reviewed as background to examining the ways in which insect parasitoids have evolved to successfully handle the immune system of the host. The various means that parasitoids utilize to handle the insect immune systems have been divided into five approaches. These five approaches are described and current knowledge of the mechanisms used by parasitoids to deal with the immune system of their host is explored.

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“…Parasitization by C. sonorensis and injection of¯uid from the oviduct (calyx¯uid) reduce the defensive plasma melanization response of H. virescens larvae, primarily by inhibiting the zymogen prophenoloxidase (E.C. 1.10.3.1; Sroka & Vinson, 1978;Stoltz & Cook, 1983). CsPDV is the causative agent which reduces plasma phenoloxidase levels (Shelby & Webb, unpubl.).…”

Section: Introductionmentioning

confidence: 98%

Polydnavirus‐mediated inhibition of lysozyme gene expression and the antibacterial response

Shelby

Cui

Webb

1998

Insect Molecular Biology

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Parasitism of lepidopteran host larvae by hymenopteran parasitoids impairs the cellular immune response via expression of polydnavirus genes. Encapsulation of parasitoid eggs is thereby prevented. Parasitized insects are susceptible to opportunistic infections, suggesting that additional components of the immune system are affected. Insects normally respond to infection by inducing the synthesis of an array of antibacterial factors, including cecropins and lysozyme via a NFkappaB/lkappaB-like signal transduction pathway. To characterize the effects of PDVs on the antibacterial immune response, plasma antibacterial activities were assayed in H. virescens larvae infected with the C. sonorensis PDV. Plasma lysozyme activity in Heliothis virescens was reduced in parasitized and PDV-infected larvae after immune challenge. To examine the regulation of lysozyme after CsPDV injection, the Heliothis virescens lysozyme cDNA was cloned. In contrast to plasma lysozyme activity, the 1.1 kb lysozyme mRNA was induced in fat body and haemocytes by known elicitors. The data suggest that CsPDV, like some other viruses, regulates host cell gene expression at the level of translation. We propose that the immunodeficiencies caused by CsPDV injection are caused, in part, by the targeted translational inhibition of specific humoral immune response transcripts.

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Phenoloxidase activity in the haemolymph of parasitized and unparasitized Heliothis virescens

Cited by 34 publications

References 21 publications

The effects of parasitism by an encyrtid parasitoid, Anagyrus pseudococci on the survival, reproduction and physiological changes of the mealybug, Planococcus citri

The effects of parasitism by an encyrtid parasitoid, Anagyrus pseudococci on the survival, reproduction and physiological changes of the mealybug, Planococcus citri

How parasitoids deal with the immune system of their host: An overview

Polydnavirus‐mediated inhibition of lysozyme gene expression and the antibacterial response

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