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Volatile Substances (volatile + substance)
Selected AbstractsIs the (E)- , -farnesene only volatile terpenoid in aphids?JOURNAL OF APPLIED ENTOMOLOGY, Issue 1 2005F. Francis Abstract:, Herbivore insects use a broad range of chemical cues to locate their host to feed or to oviposit. Whether several plant volatiles are effective allelochemicals for insects, the latter also emit molecules which have infochemical role. The (E)- , -farnesene (EBF) is a well-known aphid alarm pheromone commonly found in all previously tested species. Analysis of the released molecules from 23 aphid species, mainly collected on their natural host plant from May to July, was performed by gas chromatography,mass spectrometry. While EBF was identified as the main volatile substance in 16 species, alone or associated with other molecules, the alarm pheromone was only a minor component of the volatile molecule pattern of five other species. Moreover, two species, Euceraphis punctipennis and Drepanosiphum platanoides, did not release EBF at all but other terpenes were identified. This original observation raised the question on the utility and the source of the non-EBF volatiles. Are these potential infochemical substances produced by the aphid or only absorbed from the host plant? Here we determined that terpenes released by insects were not only provided by the host plants. Indeed, Megoura viciae emitted additional molecules than the ones from several aphid species reared on the same host plant. Moreover, no systematic relation between the feeding behaviour of the aphid species and the volatile releases was observed. Aphid terpene composition and proportion would provide reliable cues to identify the emitting organism, plant or insect. The next step of this work will be to determine the infochemical role of terpenes found in the range of tested aphid samples to better understand the relations between the different tritrophic levels. [source] The construction of web database server-client system for functional food factorsBIOFACTORS, Issue 1-4 2004Xing-Gang Zhuo Abstract In food, other than known nutrients, such as lipid, carbohydrate, protein, vitamins, and minerals, many substances with physiological function and medicinal action exist, and it is contributing to healthy improvement and/or prevention of illness. Although carotenoid, flavonoid and polyphenol, terpenoid, volatile substance and sulfur compounds, peptide, etc. have the function of illness prevention, and research of those non-nutrient functional food factors (FFF) became globally active, the research of this field is not yet done systematically. We evaluate function of FFF and reappraise known knowledge, and this knowledge is standardized and accumulated, aimed at building a web database server-client system which is easy to use for the people and nutritional research. We also collected related data such as chemical characters of FFF from literatures and other source, and formatted them into the database. We constructed the web database server-client system with MySQL database server and Apache web server based on Linux, and used Tomcat JSP engine for data connecting since they were reliable in stability and speed. We are opening the database at http://www.life-science.jp/FFF for test now. [source] Anchoring ,-cyclodextrin to retain fragrances on cotton by means of heterobifunctional reactive dyesCOLORATION TECHNOLOGY, Issue 1 2004Wang Chao-Xia Cyclodextrins are cyclic oligosaccharides which are able to form complexes with a wide range of organic compounds, including fragrance oils. As a result of the complexation, the vapour pressure of the volatile substance is reduced and its release is better controlled. To achieve this, ,-cyclodextrin can be anchored to cellulose by means of a chemical linkage provided by heterobifunctional reactive dyes. [source] Breath gas aldehydes as biomarkers of lung cancerINTERNATIONAL JOURNAL OF CANCER, Issue 11 2010Patricia Fuchs Abstract There is experimental evidence that volatile substances in human breath can reflect presence of neoplasma. Volatile aldehydes were determined in exhaled breath of 12 lung cancer patients, 12 smokers and 12 healthy volunteers. Alveolar breath samples were collected under control of expired CO2. Reactive aldehydes were transformed into stable oximes by means of on-fiber-derivatization (SPME-OFD). Aldehyde concentrations in the ppt and ppb level were determined by means of gas chromatography-mass spectrometry (GC-MS). Exhaled concentrations were corrected for inspired values. Exhaled C1,C10 aldehydes could be detected in all healthy volunteers, smokers and lung cancer patients. Concentrations ranged from 7 pmol/l (161 pptV) for butanal to 71 nmol/l (1,582 ppbV) for formaldehyde. Highest inspired concentrations were found for formaldehyde and acetaldehyde (0,55 nmol/l and 0,13 nmol/l, respectively). Acetaldehyde, propanal, butanal, heptanal and decanal concentrations showed no significant differences for cancer patients, smokers and healthy volunteers. Exhaled pentanal, hexanal, octanal and nonanal concentrations were significantly higher in lung cancer patients than in smokers and healthy controls (ppentanal = 0.001; phexanal = 0.006; poctanal = 0.014; pnonanal = 0.025). Sensitivity and specificity of this method were comparable to the diagnostic certitude of conventional serum markers and CT imaging. Lung cancer patients could be identified by means of exhaled pentanal, hexanal, octanal and nonanal concentrations. Exhaled aldehydes reflect aspects of oxidative stress and tumor-specific tissue composition and metabolism. Noninvasive recognition of lung malignancies may be realized if analytical skills, biochemical knowledge and medical expertise are combined into a joint effort. [source] Pathogen-induced resistance and alarm signals in the phloemMOLECULAR PLANT PATHOLOGY, Issue 5 2004AART J. E. VAN BEL SUMMARY Despite a long-standing notion of long-distance signals triggering systemic acquired resistance (SAR), the translocation pathway and the identity of the signals involved have not been determined with any degree of certainty. A critical assessment indicates that, in parallel to signalling via the phloem, alternative modes for SAR induction such as signalling via the xylem or air-borne signalling by volatile substances may occur. This review further evaluates several classes of compounds as being functional in systemic resistance signalling. Evidence in favour of SAR involvement of phloem-mobile substances such as salicylic acid, lipid-derived molecules, reactive oxygen species and components of the antioxidant machinery is contradictory, circumstantial or inconclusive, at best. Nitric oxide bound to proteins or thiols seems a good candidate for signalling, but has not been found in phloem sap thus far. No convincing support of the involvement in SAR of phloem-mobile substances such as calcium, oligosaccharides, peptides or RNA species, which function in other systemic signalling cascades, has yet been produced. Nevertheless, phloem-mobile macromolecules are considered as potential tools for SAR given their pivotal role in remote gene expression under stress conditions. In this framework, the existence of several cascades for signal generation along the phloem pathway is envisaged. Finally, recent methods for detection of molecular signals in phloem sap and their expression in companion cells are presented. [source] Fragrances, male display and mating behaviour of Euglossa hemichlora: a flight cage experimentPHYSIOLOGICAL ENTOMOLOGY, Issue 4 2003Thomas Eltz Abstract., Male euglossine bees (Apidae: Euglossini) collect volatile substances (fragrances) from floral and nonfloral sources and store them in hair-filled cavities in their hind tibiae. Over time, males accumulate large quantities of complex and species-specific blends of fragrances. Various hypotheses have been put forward to explain this behaviour, including the idea that fragrance stores reflect the genetic quality of individual males and have evolved through sexual selection and female choice. Clear support of this hypothesis is lacking, largely because male,female interactions are both rare and difficult to observe in nature. Here, we report a flight cage experiment performed in Panama that permitted mating between virgin females (raised from brood cells) and males captured in the forest at fragrance baits. In the cage, eight individually marked males defended small territories around vertical perch sites and showed a characteristic display, which included a previously unreported ,leg-crossing' movement, possibly related to fragrance release. A total of six copulations and three copulatory attempts by Euglossa hemichlora were observed and partly recorded on video. The copulations, all of which were initiated by the female landing on a male perch, were short (4,10 s) and showed no signs of the transfer of chemical substances from male to female. In some cases, the male hovered directly over the female before descending to mount her, possibly facilitating fragrance evaluation by the female. After the experiment, the contents of the males' hind legs were analysed by gas chromatography-mass spectroscopy, which detected complex mixtures of terpenoids and aromatics (totalling 70 different compounds) dominated by hexahydrofarnesyl acetone, farnesene epoxide, ocimene and p -dimethoxy benzene. Individual total amounts of fragrances were neither related to display activity or perch occupancy by given males, nor to the frequency of matings achieved. Display activity was the only positive correlate of mating frequency. Generally, individuals had uniformly large amounts of stored fragrances in comparison to a previous study of three other species of Panamanian Euglossa. [source] Spectroscopic study of the physical properties making trehalose a stabilizing and shelf life extending compound in food industryQUALITY ASSURANCE & SAFETY OF CROPS & FOOD, Issue 2 2010S. Magazù Abstract Introduction Trehalose, a glass-forming bioprotectant disaccharide, has been demonstrated to possess significant potential within the food industry. It does not interact with reactive molecules such as amino groups from peptides and proteins, preventing the degradation and aggregation due to Maillard reactions. Objective This paper aims to review at the molecular level the effects of trehalose on the structural and dynamical properties of water and on protein to highlight the stabilization and conservation properties on food products. Results and Conclusions The experimental findings presented show that water molecules are arranged in presence of trehalose in a particular configuration which avoids ice formation, so limiting damage due to freezing and cooling. On the other hand, homologous disaccharides, and trehalose to a greater extent, slow down the dynamics of water with a significant influence on the biological activity. These results imply that trehalose has a greater ability to bind volatile substances and deliver superior bioprotective effectiveness. Furthermore trehalose is shown to be incapable of taking part in the denaturation process of lysozyme under thermal stress. [source] Vibrational spectroscopic studies to acquire a quality control method of Eucalyptus essential oils,BIOPOLYMERS, Issue 5 2005M. Baranska Abstract This article presents a novel and original approach to analyze in situ the main components of Eucalyptus oil by means of Raman spectroscopy. The obtained two-dimensional Raman maps demonstrate a unique possibility to study the essential oil distribution in the intact plant tissue. Additionally, Fourier Transform (FT)-Raman and attenuated total reflection (ATR)-IR spectra of essential oils isolated from several Eucalyptus species by hydrodistillation are presented. Density Functional Theory (DFT) calculations were performed in order to interpret the spectra of the essential oils of the Eucalyptus species. It is shown that the main components of the essential oils can be recognized by both vibrational spectroscopic techniques using the spectral information of the pure terpenoids. Spectroscopic analysis is based on the key bands of the individual volatile substances and therefore allows one to discriminate different essential oil profiles of several Eucalyptus species. It has been found that the presented spectroscopic data correlate very well with those obtained by gas chromatography (GC) analysis. All these investigations are helpful tools to generate a fast and easy method to control the quality of the essential oils with vibrational spectroscopic techniques in combination with DFT calculations. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 237,248, 2005 [source] | |||||||||||||