Plants attract parasitic wasps to defend themselves against insect pests by releasing hexenol.
BACKGROUND: Plant volatiles play an important role in defending plants against insect attacks by attracting their natural enemies. For example, green leaf volatiles (GLVs) and terpenoids emitted from herbivore-damaged plants were found to be important in the host location of parasitic wasps. However, evidence of the functional roles and mechanisms of these semio-chemicals from a system of multiple plants in prey location by the parasitoid is limited. Little is known about the potential evolutionary trends between herbivore-induced host plant volatiles and the host location of their parasitoids. METHODOLOGY/PRINCIPAL FINDINGS: The present study includes hierarchical cluster analyses of plant volatile profiles from seven families of host and non-host plants of pea leafminer, Liriomyza huidobrensis, and behavioral responses of a naive parasitic wasp, Opius dissitus, to some principal volatile compounds. Here we show that plants can effectively pull wasps, O. dissitus, towards them by releasing a universally induced compound, (Z)-3-hexenol, and potentially keep these plants safe from parasitic assaults by leafminer pests, L. huidobrensis. Specifically, we found that volatile profiles from healthy plants revealed a partly phylogenetic signal, while the inducible compounds of the infested-plants did not result from the fact that the induced plant volatiles dominate most of the volatile blends of the host and non-host plants of the leafminer pests. We further show that the parasitoids are capable of distinguishing the damaged host plant from the non-host plant of the leafminers. CONCLUSIONS/SIGNIFICANCE: Our results suggest that, as the most passive scenario of plant involvement, leafminers and mechanical damages evoke similar semio-chemicals. Using ubiquitous compounds, such as hexenol, for host location by general parasitoids could be an adaptation of the most conservative evolution of tritrophic interaction. Although for this, other compounds may be used to improve the precision of the host location by the parasitoids. (+info)
Indoor/ambient residential air toxics results in rural western Montana.
Use of solid phase microextraction (SPME) for profiling the volatile metabolites produced by Glomerella cingulata.
The profile of volatile organic compounds (VOCs) released from Glomerella cingulata using solid phase microextraction (SPME) with different fibers, Polydimethylsiloxane (PDMS), Polydimethylsiloxane/Divinylbenzene (PDMS/DVB), Carboxen/Polydimethylsiloxane (CAR/PDMS) and Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS), was investigated. C4-C6 aliphatic alcohols were the predominant fraction of VOCs isolated by CAR/PDMS fiber. Sesquiterpene hydrocarbons represented 20.3% of VOCs isolated by PDMS fiber. During the growth phase, Ochracin was produced in the large majority of VOCs. 3-Methylbutanol and phenylethyl alcohol were found in the log phase of it. Alcohols were found in cultures of higher age, while sesquiterpenes were found to be characteristic of initial growth stage of G. cingulata. (+info)
Breath analysis in non small cell lung cancer patients after surgical tumour resection.
Exhaled volatile organic compounds (VOCs), mainly aliphatic and aromatic hydrocarbons, have been proposed as a diagnostic test for early lung cancer detection, but the effect of lung cancer surgical re-moval on exhaled VOCs pattern has never been specifically addressed. The aim of this study was to compare VOC levels measured in non small cell lung cancer (NSCLC) patients before surgery (T0), one month (T1) and 3 years (T2) after surgical removal of tumour. In order to better understand the pathophysiological meaning of exhaled aromatic hydrocarbons, the same exhaled biomarkers were also assessed in cancerous and macroscopically unaffected lung tissue samples collected during surgical operation. Exhaled breath was collected in a specially designed Teflon bulb trapping the last 150 ml of a single slow vital capacity. After solid phase micro-extraction, VOCs were analysed in gas chromatography-mass spectrometry. VOC levels were unaffected by surgical removal, except for isoprene, whose concentration was significantly reduced. Three years after surgical operation, some VOCs significantly changed from baseline: in particular, we noted a decrease in isoprene and benzene concentrations, whereas the levels of pentane, toluene and ethylbenzene were increased in comparison with baseline values. Finally, lung tissue analysis showed that all aromatic hydrocarbons, except xylenes, were significantly higher in cancerous than in unaffected tissue. This study showed that surgical operation can influence the concentration of some exhaled VOCs opening a new scenario in the use of exhaled VOCs in lung cancer patients, not only for diagnostic but also for follow up purposes. (+info)
SuperScent--a database of flavors and scents.