Physalin B inhibits Rhodnius prolixus hemocyte phagocytosis and microaggregation by the activation of endogenous PAF-acetyl hydrolase activities.
J Insect Physiol
; 55(6): 532-7, 2009 Jun.
Article
in En
| MEDLINE
| ID: mdl-19232405
ABSTRACT
The effects of physalin B (a natural secosteroidal chemical from Physalis angulata, Solanaceae) on phagocytosis and microaggregation by hemocytes of 5th-instar larvae of Rhodnius prolixus were investigated. In this insect, hemocyte phagocytosis and microaggregation are known to be induced by the platelet-activating factor (PAF) or arachidonic acid (AA) and regulated by phospholipase A(2) (PLA(2)) and PAF-acetyl hydrolase (PAF-AH) activities. Phagocytic activity and formation of hemocyte microaggregates by Rhodnius hemocytes were strongly blocked by oral treatment of this insect with physalin B (1mug/mL of blood meal). The inhibition induced by physalin B was reversed for both phagocytosis and microaggregation by exogenous arachidonic acid (10microg/insect) or PAF (1microg/insect) applied by hemocelic injection. Following treatment with physalin B there were no significant alterations in PLA(2) activities, but a significant enhancement of PAF-AH was observed. These results show that physalin B inhibits hemocytic activity by depressing insect PAF analogous (iPAF) levels in hemolymph and confirm the role of PAF-AH in the cellular immune reactions in R. prolixus.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phagocytosis
/
Rhodnius
/
Secosteroids
/
Insect Proteins
/
1-Alkyl-2-acetylglycerophosphocholine Esterase
/
Hemocytes
Limits:
Animals
Language:
En
Journal:
J Insect Physiol
Year:
2009
Document type:
Article
Affiliation country: