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PubMed2005

In situ modification of herbivore-induced plant odors: a novel approach to study the attractiveness of volatile organic compounds to parasitic wasps.

Many parasitic wasps (parasitoids) exploit volatile organic compounds (VOCs) emitted by herbivore-infested plants in order to locate their hosts, but it remains largely unknown which specific compounds within the volatile blends elicit the attractiveness to parasitoids. One way of studying the importance of specific VOCs is to test the attractiveness of odor blends from which certain compounds have been emitted. We used this approach by testing the attraction of naive and experienced females of the two parasitoids Cotesia marginiventris and Microplitis rufiventris to partially altered volatile blends of maize seedlings (Zea mays var. Delprim) infested with Spodoptera littoralis larvae. Adsorbing filter tubes containing carbotrap-C or silica were installed in a four-arm olfactometer between the odor source vessels and the arms of the olfactometer. The blends breaking through were tested for chemical composition and attractiveness to the wasps. Carbotrap-C adsorbed most of the sesquiterpenes, but the breakthrough blend remained attractive to naive C. marginiventris females. Silica adsorbed only some of the more polar VOCs, but this essentially eliminated all attractiveness to naive C. marginiventris, implying that among the adsorbed compounds there are some that play key roles in the attraction. Unlike C. marginiventris, M. rufiventris was still attracted to the latter blend, showing that parasitoids with a comparable biology may employ different strategies in their use of plant-provided cues to locate hosts. Results from similar experiments with modified odor blends of caterpillar-infested cowpea (Vigna unguiculata) indicate that key VOCs in different plant species vary greatly in quality and/or quantity. Finally, experienced wasps were more strongly attracted to a specific blend after they perceived the blend while ovipositing in a host. Considering the high number of distinct adsorbing materials available today, this in situ modification of complex volatile blends provides a new and promising approach pinpointing on key attractants within these blends. Advantages and disadvantages compared to other approaches are discussed.

Adsorption↗
PubMed2006

Electrophysiological and behavioral responses of a parasitic wasp to plant volatiles induced by two leaf miner species.

In the present study, Y-tube olfactometric assays demonstrated that headspace volatile extracts collected from leaf miner-damaged, or artificially damaged, bean plants were more attractive to naive females of the parasitoid insect Opius dissitus than those collected from healthy plants. Headspace extracts from both Liriomyza huidobrensis and Liriomyza sativae second-instar larvae-damaged beans were analyzed by coupled gas chromatography-electroantennographic detection (GC-EAD). Of nine EAD-active volatiles identified, (3E)-4,8-dimethyl-1,3,7-nonatriene, (3Z)-hexenyl acetate, (syn)-2-methylpropanal oxime, and (syn)-2-methylbutanal oxime were the most abundant compounds that evoked significant electroantennogram (EAG) responses. Compounds (3Z)-hexen-1-ol, (anti)-2-methylbutanal oxime, linalool, beta-caryophyllene, and (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene also elicited clear EAG responses but were present in smaller amounts. Choice experiments in a Y-tube olfactometer indicated that synthetic versions of (3Z)-hexen-1-ol, 2-methylpropanal oxime, 2-methylbutanal oxime, 3-methylbutanal oxime, linalool, (E,E)-alpha-farnesene, and (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene were attractive individually, while (3Z)-hexenyl acetate and (3E)-4,8-dimethyl-1,3,7-nonatriene were unattractive at concentrations similar to those obtained from the headspace collection. Moreover, a blend of nine EAD-active volatiles was significantly more attractive relative to hexane (solvent). A mixture of oximes, tereponids, and green leaf volatiles may facilitate host location by female O. dissitus.

Animals↗
PubMed1975

Gas chromatographic evaluation of the volatile constituents of lung, brain and liver tissues.

Volatile metabolites from rat liver, lung and brain tissues were compared using gas chromatography. Volatiles released from the homogenized tissues at 95-100 degrees C were collected on a poly phenyl ether solid adsorbent. The adsorbed volatiles were examined by high-resolution gas chromatography. Markedly differing overall volatile profiles were observed for the tissue types examined, and it appears that certain constituents may be characteristic of a particular tissue.

Animals↗
PubMed2003

Effect of minerals on activity of microbial uricase to reduce ammonia volatilization in poultry manure.

Inhibition of microbial uricase in poultry manure is critical to reduce NH3 volatilization, because hydrolysis of uric acid by microbial uricase is the first step in the production of NH3 gas in poultry manure. Three experiments were conducted to evaluate the effects of minerals on uricase activity and NH3 volatilization from poultry manure. In Experiment 1, an in vitro enzyme assay was used to evaluate the effects of Zn, Cu, Mg, and Mn on the activity of microbial uricase. There were three treatments: uricase, uricase + minerals, and uricase preincubated with minerals. Uric acid concentration was measured at 293 nm with a spectrophotometer. The results indicated that Zn and Cu greatly blocked the activity of microbial uricase (>90% inhibition), whereas Mg and Mn were less inhibitory. Experiment 2 was designed to evaluate the effect of ZnSO4 on the growth of uric acid-utilizing microorganisms by an in vitro assay. There were three treatments: control, ZnSO4 (10 mM), and ZnSO4 (50 mM). The results indicated that ZnSO4 significantly reduced the number of uric acid-utilizing microorganisms compared to the control. In Experiment 3, an NH3-trapping system was used to evaluate the effect of different levels of ZnSO4 on NH3 volatilization and nitrogen retention in poultry manure. Poultry manure (300 g) was mixed with 0, 0.15, 0.3, 1.5, 3, or 6 g ZnSO4 to create manure concentrations of Zn at 0, 0.05, 0.1, 0.5, 1, or 2% (wt/wt), respectively. The 1 and 2% ZnSO4 treatments significantly increased manure uric acid and total nitrogen retention by reducing NH3 volatilization compared to the control during the 3-wk incubation.

Ammonia↗
PubMed2004

The impact of supplemental dietary methionine sources on volatile compound concentrations in broiler excreta.

The impact of different Met sources on broiler fecal odor volatiles was determined by evaluating the types of sulfur compounds produced in broiler excreta. Two experiments were conducted using straight-run broiler chicks randomly distributed in battery cages, with 3 replicate pens of 16 birds each. The treatment groups were 1) dry Met hydroxy analogue (dry MetHA), 2) sodium methioninate aqueous solution (NaMet), 3) liquid Met hydroxy analogue (Liq MetHA), 4) D,L- Met, and 5) no supplemental Met (control group). The Met activities of each Met source were 52, 45.9, 88, and 98%, respectively. All diets were formulated to contain either 0.8% (experiment 1) total Met activity or 0.5% Met activity in the starter and 0.38% Met activity in the grower (experiment 2) (except the control group, 0.35% Met activity), but otherwise met NRC nutrient requirements (NRC, 1994). Diets were fed ad libitum from d 1 to 6 wk of age. There were no significant differences in BW among the treatments. All excreta were collected in litter pans lined with aluminum foil. In experiment 1, at wk 6, broiler excreta were collected for a 24-h period, and 4.5 g of broiler excreta from each treatment group was collected into 15-mL headspace vials. Samples were analyzed by gas chromatography/mass spectrometry (GC/MS). The volatile sulfur compounds that were identified and quantified in the broiler excreta were H2S, carbonyl sulfide (COS), methyl mercaptan (CH3SH), dimethyl disulfide (CH3SSCH3), and dimethyl trisulfide (CH3SSSCH3). The NaMet treatment group had significantly higher concentrations of H2S, COS, and CH3SSCH3 compared with all other treatment groups. The Liq MetHA group had significantly lower concentrations of H2S, COS, CH3SH, and CH3SSCH3 compared with the other treatment groups. The dry MetHA group significantly had the highest concentration of CH4SH. The D,L-Met treatment group had the significantly highest concentration of CH3SSSCH3 and the lowest concentration of H2S. The control group had the significantly lowest concentrations of CH3SH, CH3SSCH3, and CH3SSSCH3 compared with the other treatment groups. In experiment 2, at wk 6, an electronic nose was used to evaluate 15 air samples per treatment group. In addition, 15 air samples (containing 6 to 8 L of air in a Tedlar bag, 3 samples per treatment group) were collected for odor evaluation by a sensory panel. Electronic nose sensor data revealed that volatile compounds in broiler excreta from the control group were significantly different from the other 4 treatment groups. Evaluation of the air samples by a sensory panel determined that there was a statistically significant difference in odor threshold detection between the control group and the other treatment groups. The dilutions to threshold of control group, NaMet, dry MetHA, Liq MetHA, and D,L-Met were 350, 492, 568, 496, and 526 odor units, respectively. These findings demonstrate that dietary Met sources significantly influenced odorous volatile concentrations in broiler excreta.

Animals↗
PubMed2004

High genetic variability of herbivore-induced volatile emission within a broad range of maize inbred lines.

Maize plants (Zea mays) attacked by caterpillars release a mixture of odorous compounds that attract parasitic wasps, natural enemies of the herbivores. We assessed the genetic variability of these induced volatile emissions among 31 maize inbred lines representing a broad range of genetic diversity used by breeders in Europe and North America. Odors were collected from young plants that had been induced by injecting them with caterpillar regurgitant. Significant variation among lines was found for all 23 volatile compounds included in the analysis: the lines differed enormously in the total amount of volatiles emitted and showed highly variable odor profiles distinctive of each genotype. Principal component analysis performed on the relative quantities of particular compounds within the blend revealed clusters of highly correlated volatiles, which may share common metabolic pathways. European and American lines belonging to established heterotic groups were loosely separated from each other, with the most clear-cut difference in the typical release of (E)-beta-caryophyllene by European lines. There was no correlation between the distances among the lines based on their odor profiles and their respective genetic distances previously assessed by neutral RFLP markers. This most comprehensive study to date on intraspecific variation in induced odor emission by maize plants provides a further example of the remarkably high genetic diversity conserved within this important crop plant. A better understanding of the genetic control of induced odor emissions may help in the development of maize varieties particularly attractive to parasitoids and other biological control agents and perhaps more repellent for herbivores.

Animals↗
PubMed2004

Functional characterization of enzymes forming volatile esters from strawberry and banana.

Volatile esters are flavor components of the majority of fruits. The last step in their biosynthesis is catalyzed by alcohol acyltransferases (AATs), which link alcohols to acyl moieties. Full-length cDNAs putatively encoding AATs were isolated from fruit of wild strawberry (Fragaria vesca) and banana (Musa sapientum) and compared to the previously isolated SAAT gene from the cultivated strawberry (Fragaria x ananassa). The potential role of these enzymes in fruit flavor formation was assessed. To this end, recombinant enzymes were produced in Escherichia coli, and their activities were analyzed for a variety of alcohol and acyl-CoA substrates. When the results of these activity assays were compared to a phylogenetic analysis of the various members of the acyltransferase family, it was clear that substrate preference could not be predicted on the basis of sequence similarity. In addition, the substrate preference of recombinant enzymes was not necessarily reflected in the representation of esters in the corresponding fruit volatile profiles. This suggests that the specific profile of a given fruit species is to a significant extent determined by the supply of precursors. To study the in planta activity of an alcohol acyltransferase and to assess the potential for metabolic engineering of ester production, we generated transgenic petunia (Petunia hybrida) plants overexpressing the SAAT gene. While the expression of SAAT and the activity of the corresponding enzyme were readily detected in transgenic plants, the volatile profile was found to be unaltered. Feeding of isoamyl alcohol to explants of transgenic lines resulted in the emission of the corresponding acetyl ester. This confirmed that the availability of alcohol substrates is an important parameter to consider when engineering volatile ester formation in plants.

Acyltransferases↗
PubMed2000

Production of volatile sulphur compounds in diseased periodontal pockets is significantly increased in smokers.

OBJECTIVE: This study was undertaken in order to test the hypothesis that the consequences of tobacco smoking may include increased synthesis of toxic volatile sulphur compounds in diseased periodontal pockets. DESIGN: A cross-sectional, parallel study comparing groups of smokers and non-smokers with periodontitis and the level of volatile sulphur compounds in the gingival sulci of these subjects. PATIENTS AND METHODS: Levels of volatile sulphur compounds were measured in diseased periodontal sites of 12 smokers and 11 non-smokers using a portable sulphide monitor. Anaerobic and aerobic counts of the total cultivable subgingival microflora of both groups were also determined. RESULTS: The percentage of sites per subject with high levels of sulphides (> or = 10 units) detected in moderate (4-6 mm) and deep (> or = 7 mm) periodontal pockets was found to be significantly higher in smokers, compared to non-smokers (P = 0.040 and P = 0.005, respectively). No significant difference in the microbiological parameters tested were observed between the two groups. CONCLUSIONS: Increased production of volatile sulphur compounds may represent a further mechanism of increased susceptibility to periodontitis in smokers and also help to explain the reported association between smoking and halitosis.

Adult↗
PubMed1983

Effects of volatile fatty acids and ketone bodies on lipolysis in isolated adipocytes from Norwegian reindeer (Rangifer tarandus).

The effect of volatile fatty acids (acetate and propionate) and ketone bodies (acetoacetate and DL-3-hydroxybutyrate) on adrenaline stimulated lipolysis have been studied in isolated adipocytes from Norwegian reindeer. All four substances caused a strong (63-90%) inhibition of lipolysis, measured as glycerol release, at low concentrations of adrenaline (5 nM). At higher adrenaline concentrations (50 nM) inhibition only took place in the presence of propionate (30% inhibition) or DL-3-hydroxybutyrate (43% inhibition). DL-3-hydroxybutyrate caused a marked reduction in adrenaline stimulated glycerol release, even at very low concentrations. The effective dose causing 50% inhibition (ED50) was 1.5 mM. It is suggested that both volatile fatty acids and ketone bodies can act as important volatile regulators of lipopolysis in this high arctic ruminant undergoing great seasonal changes in volatile fatty acid and supposedly ketone body production.

3-Hydroxybutyric Acid↗
PubMed2001

Defensive function of herbivore-induced plant volatile emissions in nature.

Herbivore attack is known to increase the emission of volatiles, which attract predators to herbivore-damaged plants in the laboratory and agricultural systems. We quantified volatile emissions from Nicotiana attenuata plants growing in natural populations during attack by three species of leaf-feeding herbivores and mimicked the release of five commonly emitted volatiles individually. Three compounds (cis-3-hexen-1-ol, linalool, and cis-alpha-bergamotene) increased egg predation rates by a generalist predator; linalool and the complete blend decreased lepidopteran oviposition rates. As a consequence, a plant could reduce the number of herbivores by more than 90% by releasing volatiles. These results confirm that indirect defenses can operate in nature.

Acyclic Monoterpenes↗
PubMed1986

Quantitative gas chromatographic analysis of volatile fatty acids in spent culture media and body fluids.

Gas chromatographic analysis of volatile fatty acids for identification of obligately anaerobic bacteria and for presumptive diagnosis of anaerobic infections is now widely practiced. However, it is difficult to compare data because only a qualitative analysis is done or only chromatograms are presented instead of quantitative data on volatile fatty acid production. We compared three stationary phases for volatile fatty acid analysis of aqueous solutions and four methods of pretreating samples for gas chromatography. Quantitative analysis could be done accurately by using Carbowax as the stationary phase after pretreatment of spent culture media with Dowex columns. If only qualitative analysis is required (e.g., for presumptive diagnosis of anaerobic infections), ether extraction and headspace analysis are equally suitable. The overall variation coefficient for volatile fatty acid production by four reference strains of obligately anaerobic bacteria after 24 h of incubation was approximately 10%.

Bacteria, Anaerobic↗
PubMedDate not supplied

Treatment of snorers with a volatile oil: a randomized, double-blind placebo-controlled trial.

Snoring is a significant problem both for the patient and for the bed partner. Seventy-two male and female heavy snorers and their bed partners participated in a double-blinded, placebo-controlled study on the effects of a volatile oil administered by gargling. The patients were diagnosed as heavy snorers after they underwent overnight polysomnography showing that their apnea indexes were below 5, thus sleep apnea patients were not included in the study. The participants and their partners filled out evaluations concerning snoring intensity, mouth dryness, nasal stuffiness and the Epworth Sleepiness Scale prior to and after using the volatile oil or placebo for 14 consecutive nights. There were no statistically significant decreases in snoring as graded by the bed partner or in mouth dryness, nasal stuffiness, or the Epworth Sleepiness Scale scores graded by the patients who were randomized to use the volatile oil. The results of this study indicate that this volatile oil is not an effective treatment in patients presenting with symptoms of snoring.

Adult↗
PubMed1995

Volatile fatty acids, metabolic by-products of periodontopathic bacteria, inhibit lymphocyte proliferation and cytokine production.

Short-chain fatty acids are a major by-product of anaerobic metabolism and can be detected in gingival fluid from periodontal pockets. Since most T cells are present subjacent to the pocket epithelium in conjunction with the plasma cells, it is important to know how these T cells are affected by short-chain fatty acids produced by subgingival plaque. The purpose of this study is to examine the effects of extracellular metabolites from periodontopathic bacteria on the proliferation and cytokine production of mouse splenic cells as a potential mechanism of imbalance among host-microbial interactions. A low-molecular-weight, heat-stable agent present in the two-day culture filtrate of Porphyromonas gingivalis, Prevotella loescheii, and Fusobacterium nucleatum significantly depressed Con A- and LPS- induced cell proliferation. To determine whether short-chain fatty acids present in the filtrate could account for the depression, we tested extracted volatile and non-volatile fatty acids for their effects on mitogenic activity. The volatile fatty acids extracted from immunosuppressive supernatants greatly inhibited T- and B- cell proliferation. Among these volatile fatty acids, butyric, propionic, valeric, and isovaleric acids impaired cell proliferation dose-dependently. From gas-liquid chromatographic analysis data, it is suggested that immuno-inhibitory activities in culture filtrates are mainly attributable to butyric and isovaleric acids in P. gingivalis, to propionic, butyric, and isovaleric acids in P. loescheii, and to butyric acid in F. nucleatum. Furthermore, these fatty acids significantly depressed interleukin 2 (IL-2), IL-4, IL-5, IL-6, and IL-10 production by Con A-stimulated splenic-T cells dose-dependently.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Lack of volatilization and escape of orally administered trichloroethylene from the gastrointestinal tract of rats.

It is possible that a substantial portion of orally administered volatile organic chemicals (VOCs) may volatilize within the warm environment of the gastrointestinal (GI) tract and escape via the esophagus before being absorbed. The objective of this study was to test this hypothesis with a representative VOC, 1,1,2-trichloroethylene (TCE). Upon hepatic portal vein (PV) injection, complete systemic absorption of TCE was assumed. Thus, exhaled TCE after PV injection should originate only from pulmonary exhalation. In contrast, TCE volatilized in the gut may also contribute to the amounts of TCE exhaled by orally (PO) dosed animals. Male Sprague-Dawley rats (320-380 g) were given 8 or 16 mg TCE/kg bw in an aqueous Alkamuls emulsion (RhonePoulenc, Cranbury, New Jersey). For the PO groups both doses were given by gavage, and for the PV groups the lower dose was injected into the PV as a bolus and the higher dose given as a 20 mm infusion. Serial blood samples were taken from an indwelling carotid arterial cannula and analyzed for their TCE content by headspace gas chromatography (GC), so that the areas-under-blood-concentration-versus-time curves (AUCs) could be determined. Serial exhaled air samples were collected from a sampling port in a miniaturized one-way breathing value and TCE measured by GC analysis to delineate exhaled breath concentration-versus-time-curves (EAUCs). Exhaled breath levels of TCE paralleled blood levels of TCE throughout the monitoring periods. Evidence against the aforementioned hypothesis was provided by comparison of ratios of blood AUCs and exhaled breath EAUCs: values for ratios of AUCPO/AUCPV and EAUCPO/EAUCPV were the same, as were EAUC/AUC ratios for the PO and PV groups. The EAUCs in the PO groups should have been higher, had there been substantial extrusion of volatilized TCE fronm the GI tract.

Administration, Oral↗
PubMed2002

Volatile compounds of headspace gas in the Japanese fish sauce ishiru.

Volatile compounds from the headspace gas of ten brands of the Japanese fish sauce ishiru were analyzed by GC-MS with a thermal-desorption cold-trap system. Many volatile peaks were detected and 51 compounds were identified. The major volatile compounds in ishiru included aldehydes (such as 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and benzaldehyde), nitrogen-containing compounds (such as pyrazine derivatives and trimethylamine), sulfur-containing compounds (such as dimethyl disulfide), and ketones (such as 2-butanone and 3-methyl-2-butanone). On the other hand, volatile fatty acids were nearly absent in the headspace gas of ishiru.

Chromatography, Gas↗
PubMed2002

Induced volatiles in elicitor-treated and rice blast fungus-inoculated rice leaves.

The volatiles released from elicitor (copper chloride, jasmonic acid, UV, L-methionine and chitosan oligomer)-treated and rice blast fungus-inoculated rice leaves were collected by the solid-phase microextraction technique and analyzed by GC-MS. (Z)-3-Hexen-1-ol, monoterpenes, methyl salicylate, and sesquiterpenes were identified as elicitor-induced volatiles by a comparison of their GC retention times and mass spectra with those of authentic compounds. The different elicitors resulted in some qualitative and quantitative differences in the production of volatiles. Monoterpenes and sesquiterpenes were identified as the rice blast fungus-induced volatiles.

Chitin↗
PubMed2004

Antioxidative effects of glycosyl-ascorbic acids synthesized by maltogenic amylase to reduce lipid oxidation and volatiles production in cooked chicken meat.

Glycosylated ascorbic acids were synthesized by using the transglycosylation activity of Bacillus stearothermophilus maltogenic amylase with maltotriose to show effective antioxidative activity with enhanced oxidative stability. The modified ascorbic acids comprised mono- and di-glycosyl transfer products with an alpha-(1,6)-glycosidic linkage. The antioxidative effects of the glycosyl derivatives of ascorbic acid on the lipid oxidation of cooked chicken breast meat patties were compared, and the synergistic effect when combined with alpha-tocopherol was determined in terms of thiobarbituric acid-reactive substances (TBARS) and volatiles production during storage. The results indicate that the glycosylated ascorbic acids had very effective antioxidative activity in preventing lipid oxidation, and were better in their synergistic effect in comparison to authentic ascorbic acid, with maltosyl-ascorbic acid being the most effective. Volatiles production was highly correlated with the TBARS values in the lipid oxidation of cooked meat. The antioxidative effect preventing the production of volatiles was particularly strong on pentanal, fairly strong on propanal and butanal, and not at all on ethanal. Propanal, pentanal, and the total volatiles thus provided a good representation of the lipid oxidation status of cooked chicken meat.

Aldehydes↗
PubMed2006

Plant volatiles, rather than light, determine the nocturnal behavior of a caterpillar.

Although many organisms show daily rhythms in their activity patterns, the mechanistic causes of these patterns are poorly understood. Here we show that host plant volatiles affect the nocturnal behavior of the caterpillar Mythimna separata. Irrespective of light status, the caterpillars behaved as if they were in the dark when exposed to volatiles emitted from host plants (either uninfested or infested by conspecific larvae) in the dark. Likewise, irrespective of light status, the caterpillars behaved as if they were in the light when exposed to volatiles emitted from plants in the light. Caterpillars apparently utilize plant volatile information to sense their environment and modulate their daily activity patterns, thereby potentially avoiding the threat of parasitism.

Animals↗