TY - JOUR

T1 - The activity of phenoloxidase in haemolymph plasma is not a predictor of Lymantria dispar resistance to its baculovirus

AU - Kasianov, Nikita S.

AU - Belousova, Irina A.

AU - Pavlushin, Sergey V.

AU - Dubovskiy, Ivan M.

AU - Podgwaite, John D.

AU - Martemyanov, Vyacheslav V.

AU - Bakhvalov, Stanislav A.

PY - 2017/8/30

Y1 - 2017/8/30

N2 - Host innate immunity is one of the factors that determines the resistance of insects to their entomopathogens. In the research reported here we studied whether or not phenoloxidase (PO), a key enzyme in the melanogenesis component of humoral immunity of insects, plays a role in the protection of Lymantria dispar larvae from infection by L. dispar multiple nucleopolyhedrovirus. We studied two types of viral infection: overt and covert. The following lines of investigation were tested: i) the intravital individual estimation of baseline PO activity in haemolymph plasma followed by virus challenging; ii) the specific inhibition of PO activity in vivo by peroral treatment of infected larvae with phenylthiourea (PTU), a competitive inhibitor of PO; iii) the evaluation of PO activity in the haemolymph plasma after larval starvation. Starvation is a stress that activates the covert infection to an overt form. All of these experiments did not show a relationship between PO activity in haemolymph plasma of L. dispar larvae and larval susceptibility to baculovirus. Moreover, starvation-induced activation of covert viral infection to an overt form occurred in 70 percent of virus-carrying larvae against the background of a dramatic increase of PO activity in haemolymph plasma in the insects studied. Our conclusion is that in L. dispar larvae PO activity is not a predictor of host resistance to baculovirus.

AB - Host innate immunity is one of the factors that determines the resistance of insects to their entomopathogens. In the research reported here we studied whether or not phenoloxidase (PO), a key enzyme in the melanogenesis component of humoral immunity of insects, plays a role in the protection of Lymantria dispar larvae from infection by L. dispar multiple nucleopolyhedrovirus. We studied two types of viral infection: overt and covert. The following lines of investigation were tested: i) the intravital individual estimation of baseline PO activity in haemolymph plasma followed by virus challenging; ii) the specific inhibition of PO activity in vivo by peroral treatment of infected larvae with phenylthiourea (PTU), a competitive inhibitor of PO; iii) the evaluation of PO activity in the haemolymph plasma after larval starvation. Starvation is a stress that activates the covert infection to an overt form. All of these experiments did not show a relationship between PO activity in haemolymph plasma of L. dispar larvae and larval susceptibility to baculovirus. Moreover, starvation-induced activation of covert viral infection to an overt form occurred in 70 percent of virus-carrying larvae against the background of a dramatic increase of PO activity in haemolymph plasma in the insects studied. Our conclusion is that in L. dispar larvae PO activity is not a predictor of host resistance to baculovirus.

KW - Animals

KW - Hemolymph/enzymology

KW - Host-Pathogen Interactions

KW - Monophenol Monooxygenase/metabolism

KW - Moths/enzymology

KW - Nucleopolyhedrovirus/physiology

KW - MANDUCA-SEXTA

KW - ARMIGERES SUBALBATUS

KW - CYTOTOXIC MOLECULES

KW - INSECT VIRUS

KW - GYPSY-MOTH

KW - LIFE-HISTORY

KW - NUCLEAR-POLYHEDROSIS-VIRUS

KW - VERTICAL TRANSMISSION

KW - IMMUNE FUNCTION

KW - DISEASE RESISTANCE

UR - http://www.scopus.com/inward/record.url?scp=85028530390&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0183940

DO - 10.1371/journal.pone.0183940

M3 - Article

C2 - 28854240

AN - SCOPUS:85028530390

VL - 12

SP - e0183940

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 8

M1 - 0183940

ER -