Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: UNIPROT:P00750 (
PLA
)
16,800
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Two entomopathogenic bacteria,
Xenorhabdus
and
Photorhabdus
, are known to be able to synthesize and secrete eicosanoid biosynthesis inhibitors (EIBs) that can enhance pathogenicity of
Bacillus thuringiensis
(Bt) against different target insects. Such enhancements can be explained by the suppression of immune responses in the hemocoel by EIBs. However, little is known about the role of EIBs in the defense against Bt pathogenicity in the gut. This study was focused on the role of insect gut immunity in the defense against Bt pathogenicity, in which the cooperative effect of bacterial metabolites was assessed. Screening 14 different bacterial strains, bacterial culture broth of Photorhabdus
temperata
subsp.
temperata
ANU101 (Ptt) gave the highest cooperative effect on Bt virulence along with significant inhibitory activity against phospholipase A
2
(
PLA
2
) of
Plutella xylostella
. In gut lumen, Ptt culture broth suppressed the generation of reactive oxygen species (ROS) induced by Bt treatment and facilitated bacterial growth, similar to vitamin E, an antioxidant. To analyze the ROS source,
dual oxidase
(
Px-Duox
) and NADPH-dependent oxidase (
Px-Nox
) genes were predicted from
P. xylostella
genome and their expressions were confirmed in larval gut. RNA interference (RNAi) of
Px-Duox
expression reduced ROS levels in both gut epithelium and lumen while RNAi of
Px-Nox
expression reduced ROS levels only in gut epithelium. Ptt extract significantly suppressed gene expression levels of
Px-Duox
and
Px-Nox
, leading to lower ROS concentrations in the gut lumen. Three commercial
PLA
2
inhibitors significantly increased the insecticidal activity of Bt by suppressing ROS levels in the gut lumen. These results indicate that Ptt extract containing EBIs can prevent up-regulation of ROS level in the midgut in response to Bt infection and enhance the virulence of Bt against
P
.
xylostella
.
...
PMID:Dual Oxidase-Derived Reactive Oxygen Species Against
Bacillus thuringiensis
and Its Suppression by Eicosanoid Biosynthesis Inhibitors. 3229
In insect midgut, prostaglandins (PGs) play a crucial role in defending bacterial and malarial pathogens. However, little is known about the PG signalling pathway in the midgut. A
dual oxidase
(
Se-Duox
) with presumed function of catalysing reactive oxygen species (ROS) production in the midgut was identified in beet armyworm,
Spodoptera exigua
.
Se-Duox
was expressed in all developmental stages, exhibiting relatively high expression levels in the midgut of late larval instars.
Se-Duox
expression was upregulated upon bacterial challenge. RNA interference (RNAi) of
Se-Duox
expression significantly suppressed ROS levels in the midgut lumen. The suppression of ROS levels increased insecticidal activity of
Serratia marcescens
after oral infection. Interestingly, treatment with a
PLA
2
inhibitor prevented the induction of
Se-Duox
expression in response to bacterial challenge. On the other hand, addition of its catalytic product rescued the induction of
Se-Duox
expression. Especially, PG synthesis inhibitor significantly suppressed
Se-Duox
expression, while the addition of PGE
2
or PGD
2
rescued the inhibition. Subsequent PG signals involved cAMP and downstream components because specific inhibitors of cAMP signal components such as adenylate cyclase (AC) and protein kinase A (PKA) significantly inhibited
Se-Duox
expression. Indeed, addition of a cAMP analogue stimulated
Se-Duox
expression in the midgut. Furthermore, individual RNAi specific to PGE
2
receptor (a trimeric G-protein subunit), AC, PKA or cAMP-responsive element-binding protein resulted in suppression of
Se-Duox
expression. These results suggest that PGs can activate midgut immunity via cAMP signalling pathway by inducing
Se-Duox
expression along with increased ROS levels.
...
PMID:PGE
2
upregulates gene expression of dual oxidase in a lepidopteran insect midgut via cAMP signalling pathway. 3308 32
