Linked Life Data

14571507

Source:http://linkedlifedata.com/resource/pubmed/id/14571507

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-10-22
pubmed:abstractText
Xenorhabdus nematophilus is a Gram-negative symbiotic bacterium of the entomopathogenic nematode, Steinernema carpocapsae. The bacteria delivered into the insect hemocoel by the nematodes cause immunodepression of the target insects to protect host nematodes and themselves from the cellular immune reaction. Previous reports suggest that the immunodepression is caused by inhibition of the eicosanoid pathway that is known to be critically important to mediate cellular immunity. This study focused on the inhibitory effect of X. nematophilus on PLA2 activity of Spodoptera exigua. The PLA2 activity was functionally associated with the activation cascade of prophenoloxidase (pPO). Dexamethasone (DEX), a specific PLA2 inhibitor, inhibited pPO activation completely at the higher doses of approximately 2.4 muM in vitro condition. The inhibitory effect of DEX was reversed by the addition of arachidonic acid, the catalytic product of PLA2. By means of this in vitro PLA2 inhibitor assay system, two different PLA2 inhibitors were used to compare their inhibitory effects on the hemolymph PLA2 of S. exigua. p-Bromophenacyl bromide (BPB), a specific inhibitor of secretory PLA2 (sPLA2), significantly inhibited pPO activation, but methylarachidonyl fluorophosphates (MAFP), a specific inhibitor of cytosolic PLA2 (cPLA2), did not show any inhibitory effect. BPB also inhibited pPO activation of the plasma, though much higher PO activation and its inhibition by BPB was found in the hemocytes. Growth medium of X. nematophilus at the stationary phase had a PLA2 inhibitory effect. Via the in vitro PLA2 inhibitor assay, it was shown that the ethyl ether extract of the medium contained significant PLA2 inhibitor activity. These results indicate that X. nematophilus produces and secretes PLA2 inhibitor, which acts on BPB-susceptible PLA2 of S. exigua.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0739-4462
pubmed:author
pubmed:copyrightInfo
Copyright 2003 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
134-42
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Xenorhabdus nematophilus inhibits p-bromophenacyl bromide (BPB)-sensitive PLA2 of Spodoptera exigua.
pubmed:affiliation
School of Bioresource Sciences, College of Natural Sciences, Andong National University, Andong, Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't