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PubMed2000

Volatility of radiopharmacy-prepared sodium iodide-131 capsules.

OBJECTIVE: The aims of this study were to quantify the extent of volatilization from 131I-NaI therapeutic capsules prepared in a centralized radiopharmacy and to quantify the amount of volatile 131I released from a dispensing vial containing a compounded 131I-NaI therapy capsule. METHODS: Therapy capsules were prepared by injecting 131I oral solution into capsules containing anhydrous dibasic sodium phosphate. Volatilized activity was obtained by filtering air drawn across samples that were placed open on the bottom of a sample holder cup. Volatile 131I was captured by filtering it through 3 triethylenediamine-impregnated carbon cartridge filters, arranged in series. To quantify the amount of volatile 131I released from a dispensing vial during a simulated patient administration, a vial containing a compounded 131I therapy capsule was opened inside a collapsible plastic bag and all the air was drawn across TEDA-impregnated carbon cartridge filters. RESULTS: The 370-MBq (10-mCi) 131I capsules from the first part of the experiment released an average of 0.035% (SD 0.031%) of the capsule activity on the first day, 0.012% (SD 0.002%) on the second day, and 0.012% (SD < 0.001%) for days 3 through 5. The 37-MBq (1-mCi) 131I capsules released an average of 0.058% (SD 0.025%) on the first day, 0.029% (SD 0.009%) on the second day, and 0.020% (SD 0.004%) on the third day. The activity released from the vial during a simulated patient administration was 0.00093% of the 131I capsule activity. CONCLUSION: The amount of 131I, which volatilized daily from the exposed therapy capsules, was a small percentage of the capsule activity. The volatile 131I that would be released during a patient administration was much less than the activity that volatilized from the exposed therapy capsules.

Humans↗
PubMed2005

[Antiatherogenic effect of Huajiao volatile oil on experimental atherosclerosis in guinea pigs].

OBJECTIVE: To investigate the antiatherogenic effect of Chinese medicine Huajiao volatile oil and its possible mechanisms. METHODS: Atherosclerotic guinea pig models were duplicated by feeding high lipid forage. Thirty-six guinea pigs were randomly divided into three groups: control group, model group and Huajiao volatile oil group. Common forage (control group), high lipid forage (model group) and high lipid forage adding Huajiao volatile oil 10 mg/kg (Huajiao volatile oil group) were given to each group accordingly. After fourteen weeks, all animals were killed for the determination of the serum lipids, apolipoproteins, malonyldialdehyde (MDA), hepatic and aortic cholesterol and triglyceride concentration, and the percentage of aortic lesions covering the intimal surface. RESULTS: At the end of the 14th week, the serum lipids of model group and Huajiao volatile oil group were significantly higher than those of control group. The serum LDL level, LDL/HDL ratio, ApoB and MDA in the Huajiao volatile oil group were significantly reduced, compared with those in model group. The hepatic and aortic cholesterol and triglyceride concentration and aorta plaque area percentage of Huajiao volatile oil group were significantly lower than those of model group. CONCLUSION: Huajiao volatile oil has an inhibitory effect on the development of experimental atherosclerosis lesions in guinea pigs. The mechanism may be related to regulation of lipid metabolism and antioxidation of serum lipids.

Animals↗
PubMed2003

Effects of molasses grass, Melinis minutiflora volatiles on the foraging behavior of the cereal stemborer parasitoid, Cotesia sesamiae.

Olfactory responses of the cereal stemborer parasitoid Cotesia sesamiae to volatiles emitted by gramineous host and nonhost plants of the stemborers were studied in a Y-tube olfactometer. The host plants were maize (Zea mays) and sorghum (Sorghum bicolor), while the nonhost plant was molasses grass (Melinis minutiflora). In single-choice tests, females of C. sesamiae chose volatiles from infested and uninfested host plants and molasses grass over volatiles from the control (soil). In dual-choice tests, the wasp preferred volatiles from infested host plants to those from uninfested host plants. There was no discrimination between molasses grass volatiles and those of uninfested maize, uninfested sorghum, or infested maize. The wasp preferred sorghum volatiles over maize. Combining uninfested maize or sorghum with molasses grass did not make volatiles from the combination more attractive as compared to only uninfested host plants. Infested maize alone was as attractive as when combined with molasses grass. Infested sorghum was preferred over its combination with molasses grass. Local growth conditions of the molasses grasses influenced attractiveness to the parasitoids. Volatiles from Thika molasses grass were attractive, while those from Mbita molasses grass were not. Growing the Thika molasses grass in Mbita rendered it unattractive and vice versa with the Mbita molasses grass. This is a case of the same genotype expressing different phenotypes due to environmental factors.

Animals↗
PubMed2003

Synergistic interactions between volicitin, jasmonic acid and ethylene mediate insect-induced volatile emission in Zea mays.

Plants display differential responses following mechanical damage and insect herbivory. Both caterpillar attack and the application of caterpillar oral secretions (OS) to wounded leaves stimulates volatile emission above mechanical damage alone. Volicitin (N-17-hydroxylinolenoyl-l-glutamine), present in beet armyworm (BAW, Spodoptera exigua) OS, is a powerful elicitor of volatiles in excised maize seedlings (Zea mays cv. Delprim). We consider some of the mechanistic differences between wounding and insect herbivory in maize by examining the activity of volicitin, changes in jasmonic acid (JA) levels, and volatile emission from both intact plant and excised leaf bioassays. Compared to mechanical damage alone, volicitin stimulated increases in both JA levels and sesquiterpene volatiles when applied to intact plants. In a bioassay comparison, excised leaves were more sensitive and produced far greater volatile responses than intact plants following applications of both volicitin and JA. In the excised leaf bioassay, volicitin applications (10-500 pmol) to wounded leaves resulted in dose dependent JA increases and a direct positive relationship between JA and sesquiterpene volatile emission. Interestingly, volicitin-induced JA levels did not differ between intact and excised bioassays, suggesting a possible interaction of JA with other regulatory signals in excised plants. In addition to JA, insect herbivory is known to stimulate the production of ethylene. Significant increases in ethylene were induced only by BAW herbivory and not by either wounding or volicitin treatments. Using intact plant bioassays, ethylene (at 1 micro l l-1 or less) greatly promoted volatile emission induced by volicitin and JA but not mechanical damage alone. For intact plants, wounding, elicitor-induced JA and insect-induced ethylene appear to be important interacting components in the stimulation of insect-induced volatile emission.

Journal Article↗
PubMed2004

Nectar-related vs. human-related volatiles: behavioural response and choice by female and male Anopheles gambiae (Diptera: Culicidae) between emergence and first feeding.

The close association of Anopheles gambiae Giles with humans and its females' ability to live on human blood alone suggest that females may ignore sources of sugar in favour of human blood as a source of energy. They have limited energy reserves at emergence, and at 27 degrees C both sexes generally die if they do not feed during night 1, 24-36 h after emergence. Food preferences during this critical period were tested by measuring responses to volatiles from honey and soiled socks, which served as surrogates for nectar-related and human-related volatiles in a wind-tunnel olfactometer. Both sexes responded more strongly to honey than to human volatiles, and given a choice, preferred honey over human volatiles. After 5 days of sugar access and maturation, males continued to prefer honey volatiles, whereas females changed behaviour, responding almost exclusively to human volatiles. Night 1 experiments also demonstrated that: (i). females previously having had sugar during the night of emergence responded more strongly to human volatiles; (ii). large-bodied mosquitoes of both sexes responded more strongly to honey than small-bodied ones; and (iii). females were equally responsive to honey in both early and late scotophase but were slightly more responsive to human volatiles in late scotophase. These results indicate that for a female's first meal, sugar is a viable option and is preferred when nectar-related stimuli are strong. This supports field evidence that sugar-feeding is a significant component of A. gambiae female behaviour.

Animals↗
PubMed2004

The comparative method rules! Codon volatility cannot detect positive Darwinian selection using a single genome sequence.

All established methods for detecting positive selection at the molecular level rely on comparisons between nucleotide sequences. An exceptional method that purports to detect selection on the basis of a single genomic sequence has recently been proposed. This method uses a measure called "codon volatility," defined for each codon as the ratio between the number of nonsynonymous codons that differ from the codon under study at a single nucleotide position and the number of sense codons that differ from the codon under study at a single nucleotide position. Here, we examine various properties of codon volatility and its derivatives and use simulation of evolutionary processes to determine whether they can be used to detect selective pressures. Codons for only four amino acids (glycine, leucine, arginine, and serine) show any variation in codon volatility. Thus, codon volatility is mainly a proxy for amino acid usage, rather than for codon usage, with 65% of all synonymous changes and 27% of all nonsynonymous changes being undetectable by this measure. Genes identified by the volatility method as being subject to positive selection tend to have idiosyncratic amino acid compositions (e.g., they are glycine rich or arginine poor). An additional property of codon volatility is the near zero variance of its mean expectation, which translates into overestimated statistical significance estimates, especially in the absence of corrections for multiple comparisons. A comparison with measures of selection inferred through comparative methodology reveals no relationship between the results of the two methods. Finally, we show that codon volatility can increase in the absence of positive Darwinian selection; that is, increased codon volatility is not indicative of positive selection.

Animals↗
PubMed2002

The repolarizing effects of volatile anesthetics on porcine tracheal and bronchial smooth muscle cells.

UNLABELLED: This study was conducted to determine the effects of volatile anesthetics (potent bronchodilators) on membrane potentials in porcine tracheal and bronchial smooth muscle cells. We used a current-clamp technique to examine the effects of the volatile anesthetics isoflurane (1.5 minimum alveolar anesthetic concentration [MAC]) and sevoflurane (1.5 MAC) on membrane potentials of porcine tracheal and bronchial (third- to fifth-generation) smooth muscle cells depolarized by a muscarinic agonist, carbachol (1 microM). The effects of volatile anesthetics on muscarinic receptor binding affinity were also investigated by using a radiolabeled receptor assay technique. The volatile anesthetics isoflurane and sevoflurane induced significant repolarization of the depolarized cell membranes in the trachea (from -19.8 to -23.6 mV and to -24.8 mV, respectively) and bronchus (from -24.7 to -29.3 mV and -30.4 mV, respectively) without affecting carbachol binding affinity to the muscarinic receptor. The repolarizing effect was abolished by a Ca(2+)-activated Cl(-) channel blocker, niflumic acid. These results indicate that volatile anesthetic-induced repolarization of airway smooth muscle cell membranes might be caused by a change in Ca(2+)-activated Cl(-) channel activity and that the different repolarized effects of the volatile anesthetics could in part contribute to the different effects of volatile anesthetics on tracheal and bronchial smooth muscle contractions. IMPLICATIONS: By use of a current-clamp technique, the volatile anesthetics isoflurane and sevoflurane repolarized porcine airway smooth muscle cell membranes depolarized by a muscarinic agonist. This effect might be caused mainly by change in Ca(2+)-activated Cl(-) channel activity, not in K(+) channel activity.

Anesthetics, Inhalation↗
PubMed2000

Volatile anesthetics differentially affect immunostimulated expression of inducible nitric oxide synthase: role of intracellular calcium.

BACKGROUND: Nitric oxide released by inducible nitric oxide synthase (iNOS) plays an important role in immune responses and systemic vasodilation in septic shock. Volatile anesthetics have been reported to interfere with signal transduction and gene expression. We studied the effect of volatile anesthetics on activity and expression of iNOS and potential mechanisms of action. METHODS: Nitrite release and iNOS expression were determined using the Griess reaction and Western and Northern blot techniques, respectively, in J774 murine macrophages stimulated with lipopolysaccharide and gamma-interferon in the absence and presence of various concentrations (0.25-2.0 minimum alveolar concentration [MAC]) of volatile anesthetics (i.e., halothane, enflurane, isoflurane, desflurane). Furthermore, potential interference of volatile anesthetics with specific signal transduction pathways was investigated. RESULTS: All volatile anesthetics, studied in a time- and dose-dependent manner, suppressed nitrite production and iNOS expression in J774 macrophages stimulated by lipopolysaccharide or gamma-interferon at clinically relevant concentrations. The inhibition was completely antagonized by ionomycin but unaffected by diacylglycerol, phorbol myristate acetate, and C2-ceramide. In contrast, in cells costimulated by lipopolysaccharide plus gamma-interferon, volatile anesthetics significantly increased nitrite production and iNOS expression independent of ionomycin and other mediators studied. CONCLUSIONS: Volatile anesthetics strongly reduced the mRNA and protein levels of iNOS and NOS activity after a single stimulation with lipopolysaccharide or gamma-interferon, most likely by attenuating intracellular calcium increase. Costimnulation with lipopolysaccharide plus gamma-interferon, however, results in maximum iNOS expression and activity, which are no longer inhibited but are potentiated by volatile anesthetics by unidentified mechanisms.

Adjuvants, Immunologic↗
PubMed2002

Volatile anesthetics mimic cardiac preconditioning by priming the activation of mitochondrial K(ATP) channels via multiple signaling pathways.

BACKGROUND: Volatile anesthetics induce pharmacological preconditioning in cardiac tissue. The purpose of this study was to test whether volatile anesthetics mediate this effect by activation of the mitochondrial adenosine triphosphate-sensitive potassium (mitoK(ATP)) or sarcolemmal K(ATP) (sarcK(ATP)) channel in rat ventricular myocytes and to evaluate the signaling pathways involved. METHODS: A cellular model of ischemia with subsequent hypoosmolar trypan blue staining served to determine the effects of 5-hydroxydecanoate, a selective mitoK(ATP) channel blocker, HMR-1098, a selective sarcK(ATP) channel blocker, diazoxide, a preconditioning mimicking agent, and various modulators of putative signaling pathways on cardioprotection elicited by sevoflurane and isoflurane. Microscopy was used to visualize and measure autofluorescence of flavoproteins, a direct index of mitoK(ATP) channel activity. RESULTS: Volatile anesthetics significantly enhanced diazoxide-mediated activation of mitoK(ATP) channels as assessed by autofluorescence of myocytes. Conversely, volatile anesthetics alone did not alter mitoK(ATP) channel activity, implying a priming effect of volatile anesthetics on mitoK(ATP) channels. Administration of the protein kinase C inhibitor chelerythrine completely blocked this effect. Also, pretreatment with volatile anesthetics potentiated diazoxide-mediated protection against ischemia, as indicated by a reduction in trypan blue-positive myocytes. Importantly, cardioprotection afforded by volatile anesthetics was unaffected by the sarcK(ATP) channel blocker HMR-1098 but sensitive to modulations of nitric oxide and adenosine-G(i) signaling pathways. CONCLUSIONS: Using autofluorescence in live cell imaging microscopy and a simulated model of ischemia, the authors present evidence that volatile anesthetics mediate their protection in cardiomyocytes by selectively priming mitoK(ATP) channels through multiple triggering protein kinase C-coupled signaling pathways. These observations provide important new insight into the mechanisms of anesthetic-induced preconditioning.

Adenosine Triphosphate↗
PubMed2001

Differential sensitivity of expressed L-type calcium channels and muscarinic M(1) receptors to volatile anesthetics in Xenopus oocytes.

Since volatile anesthetics inhibited high voltage-gated calcium channels and G-protein-coupled M(1) muscarinic signaling, their effects upon M(1) receptor-induced modulation of L-type (alpha1C) calcium channel was investigated. Voltage-clamped Ba(2+) currents (I(Ba)) were measured in Xenopus oocytes coexpressed with L-type channels and M(1) muscarinic receptors. M(1) receptor agonist, acetyl-beta-methylcholine (MCh) inhibited the peak and late components of I(Ba) in a dose-dependent manner. Analysis of I(Ba) after the treatment with MCh or volatile anesthetics revealed that the inactivating component, its time constant, and the noninactivating current were all decreased by these agents. MCh-induced inhibition followed a second messenger pathway that included G-proteins, phospholipase C, inositol-1,4,5-trisphosphate, and intracellular calcium [Ca(2+)](i). Although halothane or isoflurane inhibited I(Ba,) their effect was not mediated through these intracellular second messengers. By using volatile anesthetics and MCh sequentially, and in various combinations, the susceptibility of L-type currents and their modulation by M(1) receptors to volatile anesthetics were investigated. When MCh and volatile anesthetics were administered together simultaneously, a pronounced inhibition that was approximately equal to the sum of their individual effects was seen. Halothane or isoflurane further inhibited the I(Ba) when either volatile anesthetic was administered following the inhibition produced by prior administration of MCh. However, when MCh was administered following either volatile anesthetic, its effect was significantly reduced. Thus, whereas volatile anesthetics appear to directly inhibit L-type channels, they also interfere with channel modulation by G-protein-coupled receptors, which may have functional implications for both neuronal and cardiovascular tissues.

Anesthetics, Inhalation↗
PubMed2004

Effects of including silage in the diet on volatile compound profiles in Montasio cheese and their modification during ripening.

Effects of including silage in the diet on volatile compound profiles and their modification during ripening of Montasio cheeses were examined. Twelve farms were selected and grouped according the type of forage in the ration: hay-based diets (four farms); hay and corn silage-based diets (four farms); and diets based on hay, corn silage and grass silages (four farms). For cheesemaking, 1000 kg of milk collected from two consecutive milkings was sampled from each farm and processed in the same cheese factory. Cheeses were ripened in the same cellar, in controlled humidity (78-85% relative humidity) and temperature (9-12 degrees C), until analysis. After 68 (62-74), 200 (194-206) and 360 (354-366) d of ripening, a cheese from each batch was analysed for moisture, protein and fat, volatile fatty acids (VFA) and volatile compounds. These latter were analysed by dynamic reverse carrier gas headspace gas chromatographic mass spectrometry (GC-MS) technique, scanning from m/z 29 to m/z 300 at 0.5 s cycle time. Total and individual VFA contents of cheeses did not differ between the different dietary treatments and increased linearly (P<0.01) during ripening, indicating that there were no appreciable defects of fermentation. Sixty-two volatile compounds were identified in the cheese samples: 12 aldehydes, 9 ketones, 16 alcohols, 17 esters, 2 hydrocarbons, 4 sulphur-containing compounds and 2 terpenes. Diet significantly affected the amount of total alcohols, ethanol, isobutanol, 1-penten-3-ol, 2-methyl-1-butanol and the sum of all the volatile compounds. Significant variations of 33 volatile compounds (9 aldehydes, 4 ketones, 6 alcohols, 10 esters, 1 hydrocarbons, 2 sulphur containing compounds, and 1 terpene) were observed during ripening. These results suggest that the influence of diet composition on volatile compounds of matured cheeses are related more to effects on microbial and chemical fermentations in cheese during ripening rather than to a direct transfer of molecules from milk.

Alcohols↗
PubMed2002

Influence of dietary supplementation of herb extracts on volatile sulfur production in pig large intestine.

Volatile sulfur compounds (VS) are generated in the large intestine by the bacterial metabolism of sulfate and sulfur amino acids. VS are potentially harmful to the host. The effect of dietary supplementation of herb extracts on volatile sulfur production in the large intestine of pig was evaluated in this study. The extracts Perilla frutescens (Soyou), Mentha piperita (Peppermint), and Ajuga decumbens (Kiransou) were fed to pigs equipped with a permanent cannula at the cecum. Cecal digesta were sampled and analyzed for ammonia and short-chain fatty acids (SCFA). Sampled digesta were incubated anaerobically either with or without L-methionine for 24 h to estimate volatile sulfur production in vivo. L-Methionine was supplemented to enhance methanethiol (MeSH) production. At the end of the incubation, head space concentrations of volatile sulfur compounds such as hydrogen sulfide (H2S), MeSH, and dimethyl sulfide (DMS) were determined by flame-photometric gaschromatography after the addition of 6 N HCl. Sampled digesta were also subjected to the most probable number estimations for sulfate-reducing bacteria (SRB), sulfide producer from L-methionine, and MeSH producers from L-methionine. All three herb extracts significantly decreased H2S (p<0.05), MeSH (p<0.05), and ammonia (p<0.05) production, but SCFA production was not affected (p>0.05). The number of volatile sulfur-producing bacteria did not vary among groups by the dietary supplementation of these herb extracts. Serial solvent extraction was done on these herb extracts to specify the active fractions that reduce volatile sulfur production. n-Butanol fraction of all three extracts significantly reduced volatile sulfur production in vitro.

Ajuga↗
PubMed2006

Evaluation of volatile low molecular weight insecticides using Drosophila melanogaster as a model.

Volatile insecticides, otherwise known as fumigants, have numerous uses in pest control and integrated pest management. Fumigants have been broadly applied in the protection of stored agricultural commodities and also in the elimination of structural pest infestations. However, fumigants have so far been mostly overlooked for use in management of public health pests such as flies and mosquitoes. This paper reports information on the development of a volatility bioassay for use in evaluating volatile insecticides against dipteran insects and on the use of this bioassay to compare the relative efficacy of 30 candidate compounds to Drosophila melanogaster Meig. The findings revealed seven highly effective insecticidal compounds, which include three heterobicyclics (menthofuran, thiophene and coumaran) and four formate esters [butyl, hexyl and heptyl formate and ethylene glycol diformate (EGDF)]. Ethyl formate, a compound previously identified as being a highly effective fumigant against coleopteran stored product pests, caused toxicity in Drosophila but was not as effective as other tested formates. Two volatile fumigant insecticides, dichlorvos (DDVP) and methyl isothiocyanate (MITC), were also tested as positive controls. Both of these volatile standards were significantly more toxic than the seven most effective of the novel compounds. Finally, regression analyses revealed that volatility is not entirely predictive of acute toxicity and that other structural features should be considered when designing and synthesizing volatile insecticidal compounds for future study.

Animals↗
PubMedDate not supplied

Fungal volatiles as indicators of food and feeds spoilage.

Fungal growth leads to spoilage of food and animal feeds and to formation of mycotoxins and potentially allergenic spores. Fungi produce volatile compounds, during both primary and secondary metabolism, which can be used for detection and identification. Fungal volatiles from mainly Aspergillus, Fusarium, and Penicillium have been characterized with gas chromatography, mass spectrometry, and sensory analysis. Common volatiles are 2-methyl-1-propanol, 3-methyl-1-butanol, 1-octen-3-ol, 3-octanone, 3-methylfuran, ethyl acetate, and the malodorous 2-methyl-isoborneol and geosmin. Volatile sesquiterpenes can be used for taxonomic classification and species identification in Penicillium, as well as to indicate mycotoxin formation in Fusarium and Aspergillus. Developments in sensor technology have led to the construction of "electronic noses" (volatile compound mappers). Exposure of different nonspecific sensors to volatile compounds produces characteristic electrical signals. These are collected by a computer and processed by multivariate statistical methods or in an artificial neural network (ANN). Such systems can grade cereal grain with regard to presence of molds as efficiently as sensory panels evaluating grain odor. Volatile compound mapping can also be used to predict levels of ergosterol and fungal colony-forming units in grain. Further developments should make it possible to detect individual fungal species as well as the degree of mycotoxin contamination of food and animal feeds.

Animal Feed↗
PubMed2003

Overexpression of cystathionine-gamma-synthase enhances selenium volatilization in Brassica juncea.

Selenium (Se) can be assimilated and volatilized via the sulfate assimilation pathway. Cystathionine-gamma-synthase (CGS) is thought to catalyze the synthesis of Se-cystathionine from Se-cysteine, the first step in the conversion of Se-cysteine to volatile dimethylselenide. Here the hypothesis was tested that CGS is a rate-limiting enzyme for Se volatilization. Cystathionine-gamma-synthase from Arabidopsis thaliana (L.) Heynh. was overexpressed in Indian mustard [ Brassica juncea (L.) Czern & Coss], and five transgenic CGS lines with up to 10-fold enhanced CGS levels were compared with wild-type Indian mustard with respect to Se volatilization, tolerance and accumulation. The CGS transgenics showed 2- to 3-fold higher Se volatilization rates than wild-type plants when supplied with selenate or selenite. Transgenic CGS plants contained 20-40% lower shoot Se levels and 50-70% lower root Se levels than the wild type when supplied with selenite. Furthermore, CGS seedlings were more tolerant to selenite than the wild type. There were no differences in Se accumulation or tolerance from selenate, in agreement with the earlier finding that selenate-to-selenite reduction is rate-limiting for selenate tolerance and accumulation. In conclusion, CGS appears to be a rate-limiting enzyme for Se volatilization. Overexpression of CGS offers a promising approach for the creation of plants with enhanced capacity to remove Se from contaminated sites in the form of low-toxic volatile dimethylselenide.

Arabidopsis↗
PubMed2006

Volatiles released from bean plants in response to agromyzid flies.

Liriomyza sativae Blanchard and Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) are two invasive flies in China that have caused economical damage on vegetables and ornamental plants. In this article, we report the profiles of emitted volatiles from healthy, mechanically damaged, and leafminer-damaged bean, Phaseolus vulgaris L., plants. Among 25 emitted volatiles identified, (E)-2-hexen-1-al, (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), (Z)-3-hexenyl acetate, (Z)-3-hexen-1-ol, (syn)- and (anti)-2-methylpropanal oxime, (syn)-2-methylbutanal oxime, linalool, and (E,E)-alpha-farnesene were consistently released from damaged bean plants. Combined amounts of these nine compounds made up more than 70% of the total volatiles emitted from each treatment. No qualitative differences in volatile emission were found between bean plants damaged by the two fly species; however, amounts of several major compounds induced by L. huidobrensis damage were significantly higher than those from plants damaged by L. sativae. The mechanically damaged plants released a higher proportion of green leaf volatiles than plants in the other treatments, whereas leafminer-damaged plants produced more terpenoids and oximes. Furthermore, the volatile profiles emitted from plants, damaged by adult leafminers, by second instar larvae, and even the plants with empty mines left by leafminer larvae (the pupal stage) were significantly different. The identification of volatile oximes released from damaged plants was confirmed and is discussed in a behavioral and biological control context.

Animals↗
PubMed2005

Attraction of the parasitoid Anagrus nilaparvatae to rice volatiles induced by the rice brown planthopper Nilaparvata lugens.

Anagrus nilaparvatae, an egg parasitoid of the rice brown planthopper Nilaparvata lugens, was attracted to volatiles released from N. lugens-infested plants, whereas there was no attraction to volatiles from undamaged plants, artificially damaged plants, or volatiles from N. lugens nymphs, female adults, eggs, honeydew, and exuvia. There was no difference in attractiveness between plants infested by N. lugens nymphs or those infested by gravid females. Attraction was correlated with time after infestation and host density; attraction was only evident between 6 and 24 hr after infestation by 10 adult females per plant, but not before or after. Similarly, after 24 hr of infestation, wasps were attracted to plants with 10 to 20 female planthoppers, but not to plants with lower or higher numbers of female planthoppers. The attractive time periods and densities may be correlated with the survival chances of the wasps' offspring, which do not survive if the plants die before the wasps emerge. Wasps were also attracted to undamaged mature leaves of a rice plant when one of the other mature leaves had been infested by 10 N. lugens for 1 d, implying that the volatile cues involved in host location by the parasitoid are systemically released. Collection and analyses of volatiles revealed that 1 d of N. lugens infestation did not result in the emission of new compounds or an increase in the total amount of volatiles, but rather the proportions among the compounds in the blend were altered. The total amounts and proportions of the chemicals were also affected by infestation duration. These changes in volatile profiles might provide the wasps with specific information on host habitat quality and thus could explain the observed behavioral responses of the parasitoid.

Animals↗
PubMed2006

Attraction of Spodoptera frugiperda larvae to volatiles from herbivore-damaged maize seedlings.

Plants respond to insect attack with the induction of volatiles that function as indirect plant defenses through the attraction of natural enemies to the herbivores. Despite the fact that volatiles are induced in response to caterpillar attack, their reciprocal effects on the host location behaviors of the same foraging herbivores are poorly understood. We examined orientation responses of sixth instar fall armyworm [FAW; Spodoptera frugiperda (Smith)] to odors from herbivore-damaged and undamaged maize seedlings (Zea mays var. Golden Queen) in y-tube olfactometer bioassays. While both damaged and undamaged maize seedlings were attractive compared with air, sixth instars preferred odors from damaged maize seedlings over odors from undamaged maize seedlings. Gas chromatography-mass spectrometry analysis of plant volatiles revealed that linalool and 4,8-dimethyl-1,3,7-nonatriene were the major volatiles induced by FAW herbivory 6 hr after initial damage. Given its prominence in induced plants and established attractiveness to adult FAW, linalool was evaluated both as an individual attractant and as a supplemental component of whole plant odors. Volatile linalool was more attractive than air to sixth instar FAW over a broad range of release rates. FAW also responded selectively to different amounts of linalool, preferring the higher amount. The orientation preferences of FAW were readily manipulated through capillary release of linalool into the airstream of whole plant odors. FAW preferred linalool over undamaged plant odors, and linalool-supplemented plant odors over unsupplemented plant odors, indicating that olfactory preferences could be changed by alteration of a single volatile component. These results suggest that although many induced volatiles attract natural enemies of herbivores, these defenses may also inadvertently recruit more larval herbivores to an attacked plant or neighboring conspecifics.

Animals↗