Oxidative stress and cytotoxicity elicited lipid peroxidation in hemocytes of Bombyx mori larva infested with dipteran parasitoid, Exorista bombycis.

Abstract:

:Parasitization of silkworm, Bombyx mori by invasive larva of dipteran parasitoid Exorista bombycis caused upto 20% revenue loss in sericulture. The parasitism was successful by suppressing host immune system however mechanism of immune suppression induced by E. bombycis is unknown which is unravelled here. The infestation induced cytotoxic symptoms in host hemocytes, such as vacuolated cytoplasm, porous plasma membrane, indented nuclei with condensed chromatin and dilated RER. One of the markers of necrosis is cell permeabilization, which can be measured as released lactate dehydrogenase (LDH). LDH level showed significantly (P<0.01) high release into extracellular medium in vitro after exposure of hemocytes to parasitoid larval tissue protein compared with control revealing membrane permeability and loss of cell integrity. At five minutes after exposure, cytotoxicity was 43% and was increased to 99% at 3h. The cytotoxicity is signalled by increased content of hydrogen peroxide (H2O2) causing lipid peroxidation followed by porosity in plasma membrane. A test for lipid peroxidation by measurement of lipid peroxidation breakdown product, malondialdehyde (MDA) revealed significant increase in peroxidation from one to 24 h post-invasion, with maximum at 12 h (P<0.008). Level of reactive oxygen species measured as H2O2 production increased from 6 to 12 h post-invasion and continued to increase significantly (P<0.03) reaching maximum at 48 h. These observations reveal that dipteran endoparasitoid invasion induced H2O2 production in the hemocytes causing cytotoxicity, lipid peroxidation and membrane porosity that suppressed both humoral- and cell-mediated immune responses of hemocytes in B. mori.

journal_name

Acta Parasitol

journal_title

Acta parasitologica

authors

Pooja M,Pradeep ANR,Hungund SP,Sagar C,Ponnuvel KM,Awasthi AK,Trivedy K

doi

10.1515/ap-2017-0086

subject

Has Abstract

pub_date

2017-12-20 00:00:00

pages

717-727

issue

4

eissn

1230-2821

issn

1896-1851

pii

/j/ap.2017.62.issue-4/ap-2017-0086/ap-2017-0086.xm

journal_volume

62

pub_type

杂志文章