Parasitic castration of Plutella xylostella larvae induced by polydnaviruses and venom of Cotesia vestalis and Diadegma semiclausum

Abstract

In the present study, we used gamma-ray to irradiate the female parasitoids to make wasp eggs infertile, resulting in pseudoparasitization, which allowed the analysis of maternal secretions such as polydnaviruses (PDVs) and venom in the absence of larval secretions or teratocytes by the growing parasitoids. We then investigated the spermatogenesis and components of testicular proteins of male Plutella xylostella larvae pseudoparasitized by two endoparasitoids (Cotesia vestalis and Diadegma semiclausum). The results showed that pseudoparasitism by the two endoparasitoids at the early third instar host larvae both induced smaller testes in size than those of nonparasitized host larvae. Both of them caused parasitic castration, and the degree of castration is almost as severe as in naturally parasitized hosts. This suggested that PDVs and venom played a major role in the degeneration of host testes. There are significant differences in the degree of castration induced by the two endoparasitoids, with respect to testicular growth, testicular protein concentrations, and histological changes of germ cells. Cotesia vestalis bracovirus always has a significantly stronger effect on host testicular growth and development than D. semiclausum ichnovirus. SDS-PAGE analysis indicated that synthesis of P 65 and P 67 proteins were clearly inhibited in testes of hosts that were pseudoparasitized by C. vestalis while reduction in synthesis of other proteins was not evident.

Conserved microRNA miR-8 blocks activation of the Toll pathway by upregulating Serpin 27 transcripts

“…[21][22][23] Several studies have shown that parasitic wasps have significant effects on host metabolism and development through interruption of host gene transcription, immune pathways, nutrition, and endocrine systems, and even regulate miRNA levels. 18,[24][25][26][27][28][29] Therefore, endoparasitoid wasps provide ideal biological tools to study the basic mechanisms underlying insect immune responses due to their profound impact on the host immune system.…”

Biophysical and formulation studies of theSchistosoma mansoniTSP-2 extracellular domain recombinant protein, a lead vaccine candidate antigen for intestinal schistosomiasis

“…10 A number of biophysical analyses specifically looking at the structure of model antigens bound to aluminum based hydrated gels, have revealed none or subtle effects upon the bound protein. [11][12][13][14][15][16] Even though alum adjuvantation is not expected to affect the properties of Sm-Tsp-2, future studies will be able to address and document that this indeed is the case.…”

Cotesia vestalis teratocytes express a diversity of genes and exhibit novel immune functions in parasitism

“…For pseudo-parasitization, C. vestalis adult females were exposed to a Cesium 137 source at a dose of 120 Gy for 1 h51. These gamma-irradiated females were then used to pseudo-parasitize hosts while other hosts were parasitized by normal (non-irradiated) females.…”