Odour

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Odour

  • food odour

  • Terms modified by Odour

  • odour alone
  • odour intensity
  • odour profile
  • odour source
  • odour stimulus

  • Selected Abstracts


    MHC and Preferences for Male Odour in the Bank Vole

    ETHOLOGY, Issue 9 2008
    Jacek Radwan
    Highly polymorphic major histocompatibility complex (MHC) genes are thought to play a central role in the choice of genetically compatible sexual partners in some vertebrates, although the evidence is variable across species. Here, we investigate the association between similarity in the MHC region and sexual preferences in the bank vole Myodes (=Clethrionomys) glareolus (Arvicollinae) in a laboratory setting. Females in post-partum oestrus were given the choice between the scents of two males in a Y-maze. Both males were unrelated to the female, but differed in their MHC similarity to the female. We found that females spent more time near the scent of MHC dissimilar males than those, with whom they shared MHC alleles. This suggests that bank voles use MHC-related cues to choose compatible mates. [source]


    The effect of supplementation of a white clover or perennial ryegrass diet with grape seed extract on indole and skatole metabolism and the sensory characteristics of lamb

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2007
    Nicola M Schreurs
    Abstract Condensed tannin in the form of a grape seed extract (GSE) was dosed to weaned wether lambs fed white clover (WC) or perennial ryegrass (PRG) over a 9-week period to determine whether the ,pastoral' flavour and odour of meat could be altered. The concentrations of the pastoral flavour compounds indole and skatole were determined in the rumen fluid, blood plasma and intermuscular fat. The odour and flavour of fat and meat from the slaughtered lambs was assessed by a trained panel. The rumen fluid and blood plasma concentrations of indole and skatole were higher in those lambs fed WC compared to PRG (P < 0.05) and the overall meat flavour intensity was greater when feeding WC (P < 0.01). The observed concentration of indole and skatole in the fat between WC and PRG feeding treatments was not statistically different. Power analysis indicated that increasing the number of lambs per treatment group from 20 to 65 would result in a higher fat skatole concentration (P < 0.05) being detected in lambs fed WC compared to PRG. Dosing with GSE gave a small reduction in skatole concentration in the rumen fluid and reduced plasma concentration of indole and skatole (P < 0.001). Odour and flavour scores of the fat and meat samples were not particularly high however, dosing with GSE lowered the overall and sweet odour and the sheepy, camphor, faecal and barnyard flavour (P < 0.05). Although the plasma concentration of indole and skatole suggests that GSE reduced indole and skatole formation, the intermittent supply of the GSE to the rumen environment was not sufficient to reduce their concentration in the fat. Hence, the small difference in the scores for pastoral odour and flavour attributes associated with GSE treatment may arise from other unknown factors. From a primary investigation, there was no difference in the concentration of indole and skatole in fat samples collected from carcasses before and after chilling. Further investigations into meat pastoral flavour are warranted through feeding condensed tannin-containing forages. Copyright © 2007 Society of Chemical Industry [source]


    The Smell of New Competitors: The Response of American Mink, Mustela vison, to the Odours of Otter, Lutra lutra and Polecat, M. putorius

    ETHOLOGY, Issue 5 2009
    Lauren A. Harrington
    We tested the response of wild American mink (an established alien species in the UK), to the odours of unfamiliar mink, European polecat and Eurasian otter. Polecats are similar in size and habits to mink, otters are larger than mink and a dominant competitor; both are native to the UK and both were absent during the original colonization by mink but are now undergoing natural population recoveries. The response of mink to experimental odours was assessed by counting the numbers of tracks (footprints) on rafts treated with anal gland secretions, and compared with response to a control raft, on two rivers in the Upper Thames valley, UK. Remote video showed that the number of tracks was positively correlated with the time that mink spent investigating an odour. We found that mink were attracted to the odours of both unfamiliar mink and polecats. There was little evidence that mink avoided the odour of otters. We suggest that, during an encounter with a polecat, mink may behave much as they would to a conspecific. We infer from the response of mink to the odour of otters, that, if mink do avoid otters, the mechanism of avoidance is likely to be complex, situation-dependent and perhaps affected by prior experience. [source]


    Formation of an Olfactory Search Image for Explosives Odours in Sniffer Dogs,

    ETHOLOGY, Issue 7 2005
    Irit Gazit
    The term ,search image' refers to an animal's heightened ability to detect a specific cryptic prey, after experience with that prey. Formulated in 1960 by Tinbergen (Archives Neerlandaises de zoologie, vol. 13, pp. 265,343), the search image concept has been the subject of much research, albeit almost entirely based on visual search cues in birds of prey. Given the theoretical and practical importance of this concept for foraging or searching in general, we set out to investigate whether dogs could form olfactory search images for explosive odours. Seven experienced explosives detector dogs were first tested for their ability to detect 30 g of the explosives 2,4,6-trinitrotoluene (TNT), RDX + polyisobutylene + di(2-ethylhexyl)sebacate + fuel oil (C4) or pentaerythritol tetranitrate (PETN) placed in various containers randomly distributed along a 300-m limestone track. In consecutive stages of the experiment, we altered the relative percentages of the three explosives. The results showed that the percentage of TNT containers detected by the dogs increased in trials that followed placing of a high percentage of TNT relative to other explosives and decreased in trials that follwed placing of a relatively low percentage of TNT containers. The percentage detection of C4 and PETN was not influenced by their relative abundance at any stage. Overall, these results suggest that dogs can form an olfactory search image that might aid in prey/target detection. [source]


    Response to Male Odours in Progestin Receptor- and Oestrogen Receptor-Containing Cells in Female Rat Brain

    JOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2002
    A. L. Bennett
    Abstract Sensory cues from male rats, such as odours and vaginal-cervical stimulation (VCS), play a modulatory role in female rat sexual behaviour. For example, exposure to male odours and VCS appears to be at least partially responsible for increases in sexual behaviour following repeated mating of oestradiol-primed female rats. Although there is evidence that VCS influences sexual behaviour via a ligand-independent progestin receptor (PR)-dependent mechanism, the mechanism by which odours influence sexual behaviour is not known. We tested the hypothesis that, similar to VCS, the effects of male odours on sexual behaviour are mediated by progestin receptors. Female rats were injected with the progestin antagonist, RU486, or oil vehicle and were then exposed to male-soiled bedding or clean bedding. Although exposure to male-soiled bedding resulted in higher levels of Fos immunoreactivity in brain areas associated with female sexual behaviour, the progestin antagonist did not reduce this effect. Furthermore, there was minimal coexpression of odour-induced Fos and progestin receptors in brain areas associated with female sexual behaviour. Together, these results suggest that the effects of male odours are not mediated by a PR-dependent mechanism. Therefore, we tested the hypothesis that oestrogen receptor (ER)-containing cells are involved in the effects of olfactory cues. Although there was virtually no coexpression of ER, and odour-induced Fos in brain areas associated with female sexual behaviour, exposure to male odours slightly increased the number of cells coexpressing ER, and odour-induced Fos in the posterodorsal medial amygdala. Although, these results do not support the hypothesis that the effects of odours are mediated by a PR-dependent mechanism, they suggest that integration of male odours and hormonal cues may occur in ER,-containing cells in the posterodorsal medial amygdala. [source]


    Effects of predator-induced visual and olfactory cues on 0+ perch (Perca fluviatilis L.) foraging behaviour

    ECOLOGY OF FRESHWATER FISH, Issue 2 2006
    V. N. Mikheev
    Abstract,,, Foraging juvenile fish with relatively high food demands are usually vulnerable to various aquatic and avian predators. To compromise between foraging and antipredator activity, they need exact and reliable information about current predation risk. Among direct predator-induced cues, visual and olfactory signals are considered to be most important. Food intake rates and prey-size selectivity of laboratory-reared, naive young-of-the-year (YOY) perch, Perca fluviatilis, were studied in experiments with Daphnia magna of two size classes: 2.8 and 1.3 mm as prey and northern pike, Esox lucius, as predator. Neither total intake rate nor prey-size selectivity was modified by predator kairomones alone (water from an aquarium with a pike was pumped into the test aquaria) under daylight conditions. Visual presentation of pike reduced total food intake by perch. This effect was significantly more pronounced (synergistic) when visual and olfactory cues were presented simultaneously to foraging perch. Moreover, the combination of cues caused a significant shift in prey-size selection, expressed as a reduced proportion of large prey in the diet. Our observations demonstrate that predator-induced olfactory cues alone are less important modifiers of the feeding behaviour of naive YOY perch than visual cues under daylight conditions. However, pike odour acts as a modulatory stimulus enhancing the effects of visual cues, which trigger an innate response in perch. [source]


    Predation risk allocation or direct vigilance response in the predator interaction between perch (Perca fluviatilis L.) and pike (Esox lucius L.)?

    ECOLOGY OF FRESHWATER FISH, Issue 3 2005
    A. Vainikka
    Abstract , Predation risk allocation hypothesis predicts that a prey's response to predator depends on prey's previous experience on predator. Here we tested whether the group of three perch respond differentially to pike, predator of perch, depending on the timing of high constant (HC) and high unpredictable (HU) risk periods within low constant risk periods in short-term (10 h) experiments, and whether the response is stronger during a HU risk period than during a HC risk period. Perch clearly erected the dorsal fin in response to predation risk treatments (pike odour only, odour and visible pike). Decrease in activity and increase in shoaling behaviour were observed mainly during high risk periods. However, the perch's responses to pike did not differ statistically between periods of various levels of predation risk or depending on the timing of high risk situations within constant low risk periods, and thus, suggesting that perch respond mainly to changes in the current predation risk. Resumen 1. La hipótesis de la asignación de riesgo a la predación predice que la respuesta a un predador depende de la experiencia previa de la presa al predador. En este trabajo analizamos si un grupo de tres individuos de Perca fluviatilis respondían de forma distinta a la presencia de Esox lucius, (un predador común de esta especie) y si éstas dependían del momento en el que se producen periodos de alto riesgo constante y de alto riesgo impredecible, en experimentos de corto plazo (10 horas) de riesgo bajo y constante y si la respuesta era mayor durante perí odos de riesgo impredecible y alto que durante períodos de riesgo constante alto. 2. Claramente P. fluviatilis respondió levantando la aleta dorsal en respuesta a los tratamientos de riesgo a la predación (solamente olor y olor + visibilidad de E. lucius). Una menor actividad y una mayor tendencia a la formación de bancos fueron observados durante períodos de alto riesgo. Sin embargo, las respuesta de P. fluviatilis a E. lucius no difirieron estadísticamente entre períodos de varios niveles de riesgo a la predación o entre aquellos que dependieron del momento en el que se produjeron situaciones de alto riesgo dentro de períodos de bajo riesgo constante. 3. Concluimos que P. fluviatilis puede utilizar señales olfatorias como determinantes de respuestas al riesgo a la predación y responder a aumentos de riesgo, sin excluir la posibilidad de que amenazas repetidas decrezcan la intensidad de la respuesta. Nuestros resultados, obtenidos en experimentos realizados a pequeña escala temporal, no niegan la posibilidad de la P. fluviatilis y otras especies puedan balancear la alimentación con actividades anti-predación, de acuerdo a cambios en el riesgo de predación a lo largo de escalas temporales de varios días. [source]


    Olfactory responses of two species of grasshoppers to plant odours

    ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2000
    H.H. Chen
    Abstract Electroantennogram (EAG) responses were recorded from two species of oedipodine grasshoppers, Oedaleus decorus asiaticus L. (graminivorous) and Angaracris barabensis Pall. (forbivorous), to volatiles emitted by chopped leaves of ten plant species. Male O. d. asiaticus showed much stronger EAG responses than conspecific females and both sexes of A. barabensis. Sexual differences in EAG responses correspond to different numbers of antennal sensilla of both sexes and to certain behavioural and morphological factors as well. The overall EAG response profiles of the two grasshopper species to the ten plant odours were similar. However, adaptation to host odour might have occurred because of differences in their feeding habits. Females of the graminivorous O. d. asiaticus possess a significantly higher olfactory sensitivity for poaceous plant species than A. barabensis, while the forbivorous A. barabensis showed significantly higher EAG responses to Allium senescens (Liliaceae), and a tendency of high responses to composite plant species in comparison with O. d. asiaticus. [source]


    The Smell of New Competitors: The Response of American Mink, Mustela vison, to the Odours of Otter, Lutra lutra and Polecat, M. putorius

    ETHOLOGY, Issue 5 2009
    Lauren A. Harrington
    We tested the response of wild American mink (an established alien species in the UK), to the odours of unfamiliar mink, European polecat and Eurasian otter. Polecats are similar in size and habits to mink, otters are larger than mink and a dominant competitor; both are native to the UK and both were absent during the original colonization by mink but are now undergoing natural population recoveries. The response of mink to experimental odours was assessed by counting the numbers of tracks (footprints) on rafts treated with anal gland secretions, and compared with response to a control raft, on two rivers in the Upper Thames valley, UK. Remote video showed that the number of tracks was positively correlated with the time that mink spent investigating an odour. We found that mink were attracted to the odours of both unfamiliar mink and polecats. There was little evidence that mink avoided the odour of otters. We suggest that, during an encounter with a polecat, mink may behave much as they would to a conspecific. We infer from the response of mink to the odour of otters, that, if mink do avoid otters, the mechanism of avoidance is likely to be complex, situation-dependent and perhaps affected by prior experience. [source]


    First Documentation of Cultural Transmission of Predator Recognition by Larval Amphibians

    ETHOLOGY, Issue 6 2007
    Maud C. O. Ferrari
    Predation is a pervasive selective agent shaping a prey's behaviour, morphology and life history. To survive, prey animals have to respond adaptively to predation threats and this can be achieved through learned predator recognition. Cultural transmission of predator recognition is likely a widespread means of learning in social animals, including mammals, birds and fishes. However, no studies have investigated the cultural transmission of predator recognition in amphibians. In our study, we examined whether naïve woodfrog (Rana sylvatica) tadpoles can acquire the recognition of the odour of a predatory tiger salamander (Ambystoma tigrinum) from experienced conspecifics. After conditioning some tutors to recognize salamander odour, we paired naïve observer tadpoles with either a salamander-naïve or salamander-experienced tutor and exposed the pairs to either salamander odour or a water control. Observers were subsequently tested alone for a response to salamander odour. We found that when given salamander odour, observer tadpoles that were paired with a salamander-experienced tutor successfully learned to recognize the salamander odour as a threat, whereas the observers paired with salamander-naïve tutors did not. Likewise, tadpoles exposed to the water control did not learn to recognize the salamander regardless of whether they were paired with a naïve or experienced tutor. This is the first study demonstrating cultural transmission of predator recognition in an amphibian species. [source]


    Individual Odour Similarity and Discrimination in the Coruro (Spalacopus cyanus, Octodontidae)

    ETHOLOGY, Issue 6 2006
    Petra Hagemeyer
    Previous studies of subterranean, fossorial and above-ground rodents have demonstrated that similarities in individual odours covary with genetic similarities thus supporting the theory of odour-genes covariance (i.e. the closer the individuals are genetically, the greater the similarities between their odours). We used the habituation-generalization paradigm, where the subject is exposed to the same odour stimulus in three consecutive habituation trials followed by two test trials in which the odour from two other individuals are presented successively. Using this test design, we showed that the socially living coruros (Spalacopus cyanus) discriminate individuals on the basis of their ano-genital odours and also respond to odour similarities between individuals. Male and female subjects treated ano-genital odours of two same-sex family members and also the odours of two sibling strangers as different to each other. At the same time, they treated the odours of siblings as similar compared with the odour of an unrelated individual. No gender differences were detected. Our results contrast with those from other rodent species that did not spontaneously discriminate between individual odours of siblings from a different family than their own. The polygyneous lifestyle may provide the selective background for that difference. Additional research will be necessary to explore this hypothesis and to rule out differences due to dietary preferences and due to the type of paradigm chosen for the tests. [source]


    Predator Inspection Behaviour in a Characin Fish: an Interaction between Chemical and Visual Information?

    ETHOLOGY, Issue 9 2003
    Grant E. Brown
    Recent evidence suggests that predator inspection behaviour by Ostariophysan prey fishes is regulated by both the chemical and visual cues of potential predators. In laboratory trials, we assessed the relative importance of chemical and visual information during inspection visits by varying both ambient light (visual cues) and predator odour (chemical cues) in a 2 × 2 experimental design. Shoals of glowlight tetras (Hemigrammus erythrozonus) were exposed to a live convict cichlid (Archocentrus nigrofasciatus) predator under low (3 lux) or high (50 lux) light levels and in the presence of the odour of a cichild fed tetras (with an alarm cue) or swordtails (Xiphophorus helleri, with an alarm cue not recognized by tetras). Tetras exhibited threat-sensitive inspection behaviour (increased latency to inspect, reduced frequency of inspection, smaller inspecting group sizes and increased minimum approach distance) towards a predator paired with a tetra-fed diet cue, regardless of light levels. Similar threat-sensitive inspection patterns were observed towards cichlids paired with a swordtail-fed diet cue only under high light conditions. Our data suggest that chemical cues in the form of prey alarm cues in the diet of the predator, are the primary source of information regarding local predation risk during inspection behaviour, and that visual cues are used when chemical information is unavailable or ambiguous. [source]


    Responses of Snow Voles, Chionomys nivalis, Towards Conspecific Cues Reflect Social Organization during Overwintering Periods

    ETHOLOGY, Issue 11 2002
    Juan J. Luque-Larena
    Among microtine rodents, reaction to chemical cues from conspecifics is assumed to reflect social and spatial relationships. Generally, strong attraction of particular odours correlates with non-aggressive behaviour and high spatial tolerance towards odour donors, whereas weak attraction correlates with greater levels of aggression and spatial segregation. In the present study, we examined whether winter odour preferences of the snow vole Chionomys nivalis, a rock-dwelling microtine principally found at high-mountainous regions, differ from that of other vole species, owing to their different social organization during overwintering periods. The social structure of C. nivalis over the winter period is relatively unusual among vole species in that they become nomadic and solitary. In odour choice trials under laboratory conditions, we found that both males and females avoided zones with conspecific odours of both sexes in comparison with unscented control zones or own odours. These results are consistent with the elevated levels of intraspecific aggression and spatial isolation of C. nivalis during overwintering periods. Furthermore, scent-elicited self-grooming increased when their own odour was offered against conspecific cues. This, in combination with an active avoidance of conspecific odours, might functionally contribute to minimize direct confrontations between solitary individuals, thereby reducing the risks of aggressive encounters during overwintering periods. [source]


    Oxidative stability and acceptability of camelina oil blended with selected fish oils

    EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 8 2010
    Deirdre Ní Eidhin
    Abstract The effects of blending camelina oil with a number of fish oils on oxidative stability and fishy odour were evaluated. Camelina oil was found to be more stable than tuna oil, ,omega-3' fish oil and salmon oil as indicated by predominantly lower ,-anisidine (AV), thiobarbituric acid reactive substances (TBARS) and conjugated triene levels (CT) during storage at 60,°C for 20,days (p,<,0.05). Peroxide values (PV) were similar for all oils until Day 13 when values for camelina oil were higher. Values for blends of the fish oils (50, 25, 15, 5%) with camelina oil were generally between those of their respective bulk oils indicating a dilution effect. Camelina oil had a similar odour score (p,<,0.05) to sunflower oil (9.2 and 9.6, respectively) indicating, as expected, an absence of fishy odours. In comparison, the fish oils had lower scores of 6.1 to 6.6 (p,<,0.05) indicating mild to moderate fishy odours. Odour scores were improved at the 25% fish oil levels (p,<,0.05) and were not different to camelina oil at the 15 or 5% levels (p,<,0.05). Practical applications: Camelina oil is a potentially important functional food ingredient providing beneficial n-3 PUFA. Oil extracted from Camelina sativa seeds contains greater than 50% polyunsaturated fatty acids of which 35-40% is ,-linolenic acid (C18:3,3, ALA), an essential omega-3 fatty acid 1. While EPA and DHA from fish oils are more potent nutritionally, they are less stable than ALA. This work evaluated innovative blends of fish oil with camelina oil for stability and acceptability. The results demonstrate that there is potential for use of blends of camelina oil with fish oils in food products, as the results show some benefits in terms of reduction of fishy odours. Such information could be valuable in relation to formulation of food products containing high levels of n-3 PUFA from both plant and fish sources. [source]


    Single olfactory sensory neurons simultaneously integrate the components of an odour mixture

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2003
    Patricia Duchamp-Viret
    Abstract Most odours are complex mixtures. However, the capacities of olfactory sensory neurons (OSNs) to process complex odour stimuli have never been explored in air-breathing vertebrates. To face this issue, the present study compares the electrical responses of single OSNs to two odour molecules, delivered singly and mixed together, in rats in vivo. This work is the first aimed at demonstrating that single OSNs simultaneously integrate several chemical signals and which, furthermore, attempts to describe such processes for the whole concentration range over which single OSNs can work. The results stress that complex interactions occur between components in odour mixtures and that OSN responses to such mixtures are not simply predictable from the responses to their components. Three types of interactions are described. They are termed suppression, hypoadditivity and synergy, in accord with psychophysical terminology. This allows us to draw links between peripheral odour reception and central odour coding. Indeed, events occurring in single OSNs may account for the dominating or even the masking effects of odour molecules in complex mixtures, i.e. for the prevailing action of a minor component in the final qualitative perception of a mixture. We conclude that our observations with binary mixtures anticipate the complexity of processes which may rise at the level of a single OSN in physiological conditions. Following this hypothesis, a natural odour would induce a multi-chemical integration at the level of single OSNs which may result in refining their individual odour-coding properties, leading them to play a crucial role in the final performance of the olfactory system. [source]


    Odour-evoked [Ca2+] transients in mitral cell dendrites of frog olfactory glomeruli

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2001
    Kerry Delaney
    Abstract We measured Ca2+ concentration, [Ca2+], transients in mitral cell distal apical dendritic tufts produced by physiological odour stimulation of the olfactory epithelium and electrical stimulation of the olfactory nerve (ON) using two-photon scanning and conventional wide-field microscopy of Ca2+ -Green-1 dextran in an in vitro frog nose,brain preparation. Weak or strong ON shock-evoked fluorescence transients always had short latency with an onset 0,10 ms after the onset of the bulb local field potential, rapidly increasing to a peak of up to 25% fractional fluorescence change (,F/F) in 10,30 ms, were blocked by 10 µm CNQX, decaying with a time constant of about 1 s. With stronger ON shocks that activated many receptor axons, an additional, delayed, sustained AP5-sensitive component (peak at ,,0.5 s, up to 40% ,F/F maximum) could usually be produced. Odour-evoked [Ca2+] transients sometimes displayed a rapid onset phase that peaked within 50 ms but always had a sustained phase that peaked 0.5,1.5 s after onset, regardless of the strength of the odour or the amplitude of the response. These were considerably larger (up to 150% ,F/F) than those evoked by ON shock. Odour-evoked [Ca2+] transients were also distinguished from ON shock-evoked transients by tufts in different glomeruli responding with different delays (time to onset differed by up to 1.5 s between different tufts for the same odour). Odour-evoked [Ca2+] transients were increased by AMPA-kainate receptor blockade, but substantially blocked by AP5. Electrical stimulation of the lateral olfactory tract (5,6 stimuli at 10 Hz) that evoked granule cell feedback inhibition, blocked 60,100% of the odour-evoked [Ca2+] transient in tufts when delivered within about 0.5 s of the odour. LOT-mediated inhibition was blocked by 10 µm bicuculline. [source]


    Engineering input/output nodes in prokaryotic regulatory circuits

    FEMS MICROBIOLOGY REVIEWS, Issue 5 2010
    Aitor De Las Heras
    Abstract A large number of prokaryotic regulatory elements have been interfaced artificially with biological circuits that execute specific expression programs. Engineering such circuits involves the association of input/output components that perform discrete signal-transfer steps in an autonomous fashion while connected to the rest of the network with a defined topology. Each of these nodes includes a signal-recognition component for the detection of the relevant physicochemical or biological stimulus, a molecular device able to translate the signal-sensing event into a defined output and a genetic module capable of understanding such an output as an input for the next component of the circuit. The final outcome of the process can be recorded by means of a reporter product. This review addresses three such aspects of forward engineering of signal-responding genetic parts. We first recap natural and non-natural regulatory assets for designing gene expression in response to predetermined signals , chemical or otherwise. These include transcriptional regulators developed by in vitro evolution (or designed from scratch), and synthetic riboswitches derived from in vitro selection of aptamers. Then we examine recent progress on reporter genes, whose expression allows the quantification and parametrization of signal-responding circuits in their entirety. Finally, we critically examine recent work on other reporters that confer bacteria with gross organoleptic properties (e.g. distinct odour) and the interfacing of signal-sensing devices with determinants of community behaviour. [source]


    Character impact odorants from wild mushroom (Lactarius hatsudake) used in Japanese traditional food

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2010
    Mitsuo Miyazawa
    Abstract The components of the volatile oil from wild mushroom (Lactarius hatsudake), used in Japanese traditional food, were analysed and quantified for the first time by capillary GC and GC,MS. Seventy-six components were separated from the oil and of these 71 components were identified. The main components of the oil were oxidized sesquiterpenes [cis -isolongifolanone (624.9,,g/100,g), , -cedrene epoxide (578.7,,g/100,g), humulene epoxide III (453.9,,g/100,g), clovane (425.4,,g/100,g)], aliphatic acids [linoleic acid (585.9,,g/100,g) and palmitoleic acid (333.3,,g/100,g)]. Odour evaluation of the volatile oil from L. hatsudake was also carried out using GC,MS/olfactometry (GC,MS/O) and aroma extract dilution analysis (AEDA), from which it was found that hexanal, 4-dehydroviridiflorol, myliol and phenylacetaldehyde seem to contribute to the green, spicy and sweet odour of L. hatsudake. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Characterization of the aroma-active compounds in five sweet cherry cultivars grown in Yantai (China)

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2010
    Shu Yang Sun
    Abstract This study was conducted to determine the aroma-active compounds of five sweet cherry cultivars grown in Yantai region, China, viz. ,Lapins', ,Rainier', ,Stella', ,Hongdeng' and ,Zhifuhong'. The samples were extracted by headspace solid phase microextraction (HS,SPME) and analysed by gas chromatography,mass spectrometry (GC,MS) on DB-wax and DB-5 columns. A total of 52 volatiles were identified. Among these, hexanal, (E)-2-hexenal, 1-hexanol, (E)-2-hexen-1-ol, benzaldehyde and benzyl alcohol were the main volatile compounds in the five cherries. Furthermore, the aroma compounds of five cherry samples were evaluated using a combination of HS,SPME and GC,olfactometry (GC,O) dilution analysis, and a total of 40 aroma-active compounds were identified. The results suggested that hexanal, (E)-2-hexenal, (Z)-3-hexenal, nonanal, benzaldehyde and geranylacetone (FD , 16), responsible for the green, orange, almond and floral characters of the cherries, were the potentially important common odorants in these cherry cultivars. Benzyl alcohol and linalool were significant aroma compounds in most cherries, with the exception of ,Stella' and ,Rainier'. In addition, (E,Z)-2,6-nonadienal (cucumber-like odour) could be important to ,Hongdeng' and ,Zhifuhong', and (E,E)-2,4-nonadienal (fatty odour) probably made great contributions to the aromas in ,Lapins' and ,Stella'. From the present result, it was concluded that the aroma profiles were similar in the five cherry cultivars, but significant variation was found in the contributions of these compounds to each cherry. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Cross-adaptation of a model human stress-related odour with fragrance chemicals and ethyl esters of axillary odorants: gender-specific effects

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2009
    Charles J. Wysocki
    Abstract The human axillae have a characteristic odour that is comprised of or generated from a mixture of C6,C11 normal, branched, hydroxy- and unsaturated acids (and other compounds). We used ethyl esters of one of these acids and a palette of fragrance compounds (tested individually) to evaluate the effectiveness of these chemicals to reduce the overall olfactory impact of a model of human stress-related odour (SRO) by cross-adaptation (adaptation to one odorant can reduce sensitivity to other odorants). Sensory volunteers provided hedonic and intensity ratings of the SRO and of each of the potential cross-adapting agents prior to 2.5 min of induced olfactory adaptation to each agent. Across adaptation, possible cross-adaptation was evaluated by intermittent evaluations of the perceived intensity of the SRO. We determined that some potential cross-adapting agents did reduce the impact of the SRO; however, the same chemicals were not necessarily effective for male and female SRO. Indeed, the list of effective chemicals depended upon the gender of the donor of the SRO and the gender of the sensory volunteer, suggesting a gender-specific response to both the SRO-stimuli used and the fragrance chemicals used to cross-adapt it. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Lichen extracts as raw materials in perfumery.

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2009
    Part 1: oakmoss
    Abstract A comprehensive review is presented on extracts of a lichen, oakmoss (Evernia prunastri), that are used in the fragrance industry. Analytical aspects are discussed in detail, from both qualitative and quantitative standpoints, mainly in relation to the industrial processing of the lichen. It is shown that more than 170 constituents have been identified so far in oakmoss extracts, including 47 depsides or depside-derived compounds and 25 triterpenes or steroids. A survey of industrially relevant synthetic products with an oakmoss odour is included. Toxicology issues related to the use of oakmoss extracts in cosmetics and fragrance formulations are critically reviewed. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Impact of estragole and other odorants on the flavour of anise and tarragon

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2007
    Annette Zeller
    Abstract Since estragole has been described as potent carcinogen and did not show any flavour impact on the odour of fennel, the flavour of anise and tarragon was examined by combinations of instrumental and sensory analyses. In anise fruits, trans- anethole, 2-isopropyl-3-methoxypyrazine, and anisaldehyde showed high flavour dilution (FD) factors, followed by those of eugenol, cis- anethole, estragole and linalool. Quantitation of the odorants showing higher FD factors in anise tea, and calculation of odour activity values (OAVs) by dividing the concentrations of the respective compound by its recognition threshold in water revealed the highest OAV for trans- anethole, followed by those of anisaldehyde and estragole. Still, an aroma impact of estragole next to trans- anethole could be neglected, due to former sensory studies of aqueous models of fennel tea. For tarragon, AEDA revealed the highest FD factors for eugenol, 7-methoxycoumarin, , -ionone, 2-isopropyl-3-methoxypyrazine, estragole and linalool. Of these, estragole and 7-methoxycoumarine were most abundant in tarragon leaves, showing contents of 2900 and 220 mg/kg, respectively. To calculate OAVs, the contents of potent odorants were divided by their odour threshold in starch or cellulose, as these were the main constituents of the leaves. In this way, , -ionone and eugenol showed the highest OAVs of 5862 and 2653, repectively, followed by estragole (OAV = 460), cis- 1,5-octadiene-3-one (OAV = 140), vanilline (OAV = 139) and 2-isopropyl-3-methoxypyrazine (OAV = 130). Therefore, it was concluded that , -ionone and eugenol made the greatest contribution to the overall flavour of tarragon, whereas estragole and the other odorants were of minor importance. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Flavour volatiles of flowers and stalks of Murraya koenigii L.

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2006
    S. G. Walde
    Abstract The volatiles of fresh leaf stalks and flowers of Murraya koenigii (curry leaf plant), grown in Hyderabad, India, were isolated by simultaneous distillation and extraction method and analysed by GC,MS. Thirty-one components were identified in the leaf stalk oil, constituting 88.1% of the volatile oil. The major components were the mono- and sesquiterpene hydrocarbons (66.7%), of which the major ones were , -pinene (24.2%), , -pinene (6.9%), , -phellandrene (7.3%) and , -copaene (8.9%). In addition, the oil had nine oxygenated monoterpenes (14.2%) and four sesquiterpene alcohols (8.1%). In the flower oil, 24 components were identified, constituting 91.8% of the volatile oil. Here, too, the major constituents were mono- and sesquiterpenes (87%), of which cis -ocimene (34.1%), , -pinene (19.1%), , -terpinene (6.7%) and , -caryophyllene (9.5%) were predominant. It also contained seven oxygenated monoterpenes and three oxygenated sesquiterpenes, constituting 4.7% of the oil. The larger number of oxygenated mono- and sesquiterpenes present appear to be responsible for the intense odour associated with the stalk and flower parts of Murraya koenigii as compared to the leaf. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Light-induced controlled release of fragrance aldehydes from 1-alkoxy-9,10-anthraquinones for applications in functional perfumery,,

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2006
    Barbara Levrand
    Abstract Light-activated chemical delivery systems for the controlled release of fragrances have been shown to be effective in functional perfumery. Upon photolysis around 350 nm, 1-alkoxy-9,10-anthraquinones release aldehydes or ketones and may thus be considered as promising precursors for the photochemical release of perfume molecules. A series of substituted and unsubstituted mono- and dialkoxy-9,10-anthraquinones was prepared by reaction of the corresponding fragrance bromides with commercial mono- or dihydroxy-9,10-anthraquinones. Photoirradiation of these compounds in polar and apolar solution yielded the desired fragrance aldehydes. Preliminary olfactory panel evaluations on fabric after exposure to ambient indoor daylight for several days indicated a slightly stronger odour in the presence of the fragrance precursors, as compared to a reference sample containing the unmodified perfumery raw material. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    New lactones in liquorice (Glycyrrhiza glabra L.),

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2006
    Regula Näf
    Abstract The lactonic fraction of a commercial liquorice root extract (licorice, Glycyrrhiza glabra L., family Fabaceae), exhibiting a pleasant sweet, woody, dried fruit-like odour, contains mainly fatty acids (C2,C16) and phenols (phenol, guaiacol), together with common saturated linear , -lactones (C6,C14) and, in trace amounts, a series of new 4-methyl- , -lactones and 4-ethyl- , -lactones. Their structures have been confirmed by synthesis. Spectral data and organoleptic descriptors are given. Some 5-methyl- , -lactones, which can easily be confused with the 4-ethyl- , -lactones, are also discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Evaluation of odour-active compounds in roasted shrimp (Sergia lucens Hansen) by aroma extract dilution analysis

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2005
    Susumu Ishizaki
    Abstract In an investigation of roasted shrimp odour adsorbed by Tenax TA during the roasting of sun-dried sakuraebi (Sergia lucens Hansen), 31 odour-active compounds were detected by application of an aroma extract dilution analysis and subsequently identified by GC,MS analysis. Among these odorants, the following six contributed to roasted shrimp aroma, with high flavour dilution (FD) factors: methanethiol (sulphury); 1-pyrroline (shrimp meat-like); N -(2,-methylbutyl)pyrrolidine (roasted seafood-like); N -(3,-methylbutyl)pyrrolidine (roasted seafood-like); methyl isopropyl disulphide (roasted shrimp meat-like); 3-methylpyridine (fishy, green). Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Supercritical carbon dioxide extraction of 2-acetyl-1-pyrroline and volatile components from pandan leaves

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2004
    Natta Laohakunjit
    Abstract The ,avour of pandan (Pandanus amaryllifolius Roxb.) leaves was extracted by supercritical ,uid with CO2 (SC-CO2) under different conditions of pressure, temperature and contact time to determine the yield of 2-acetyl-1-pyrroline (ACPY) and various other components; 14 volatile compounds on the gas chromatogram were identi,ed, and the predominant constituents were ACPY and 3-methyl-2(5H)-furanone. The interaction of different conditions signi,cantly in,uenced the yield of ACPY and various volatile compounds. There is a potential for high yield of ACPY by SC-CO2 at 200 bar, 500 °C and 20 min. The SDE,ether extract was found to have a very small amount of ACPY and an undesirable odour, as compared to the dark green ethanol extract, which contains a relatively larger quantity of ACPY and even more 3-methyl-2(5H)-furanone. Although at least 34 new components were uncovered from SC-CO2, SDE, and ethanol extraction, both ACPY and 3-methyl-2(5H)-furanone were the components tentatively obtained by all three methods. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Comparative study of odour and GC-olfactometric profiles of selected essential oils

    FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2001
    Anupama Kamath
    Abstract The market demand for novel foods and beverages is increasing. The blending of flavour notes to create an exotic one, to satisfy the tastes and fantasies of the modern generation, may soon become a major task for researchers. In order to achieve this, it is essential to study the single flavourant thoroughly, and the dominant and subtle notes in them, prior to blending. In the present study, profiling of four essential oils, viz. lemongrass, rosemary, geranium and davana, were carried out by two methods, GC-olfactometry (GC,O) and per se odour profile by trained panelists. The attributes of odour analysis and GC,O were compared using spider-web plots. The study showed that although some odour notes perceived by sniffing the oils directly and those perceived by sniffing the effluent of GC at different retention times (RTs) varied, the dominant notes were similar. The odour profiling per se depicts the overall odour perceived, while the GC,O aromagrams represent the picture of odour notes of fractionated volatiles at the respective retention times. The results of the study gives an in-depth description of odour notes in the essential oil and helps the technologist to blend them to achieve the required flavour notes. Thus, the study finds its application in the development of designer beverages containing essential oils or blends of oils with the desired odour characteristics. Copyright © 2001 John Wiley & Sons, Ltd. [source]


    Olfactory information saves venom during prey-capture of the hunting spider Cupiennius salei (Araneae: Ctenidae)

    FUNCTIONAL ECOLOGY, Issue 2 2006
    S. HOSTETTLER
    Summary 1The Neotropical spider Cupiennius salei Keyserling (Ctenidae) selects prey in a manner consistent with the amount of venom available in its venom glands. It distinguishes the venom sensitivity of different prey species, and uses its venom economically (according to the venom-optimization hypothesis). 2A prey-choice experiment was performed to test whether spiders use olfactory cues to detect prey and select prey items that are appropriate for their amount of available venom. 3The spider could choose between two similar prey dummies made of agar. We added the odour of two prey species, either by adding minced insects to an agar block or by offering it on filter paper which had previously been exposed to the living prey. Cupiennius salei spiders had either full or emptied venom glands. 4Two insects of distinctive venom sensitivity, but high acceptance, were tested: a sensitive cricket and a less sensitive cockroach. 5Using video surveillance, we found an attraction effect of prey odour in the prey-capture behaviour of C. salei. Spiders preferred agar pieces with minced insects or insect odour on filter paper over non-smelling items. Reaction frequency and attack rates were equal for spiders with full venom glands if they had to choose between cricket and cockroach odour. When the venom glands were empty, however, C. salei significantly preferred the venom-sensitive cricket over the venom-insensitive cockroach. 6We showed for the first time that C. salei uses its olfactory sense to detect prey items, and distinguishes between prey species with low and high sensitivity to spider venom. This study supports the venom-optimization hypothesis. [source]


    Classical reward conditioning in Drosophila melanogaster

    GENES, BRAIN AND BEHAVIOR, Issue 2 2007
    Y-C. Kim
    Negatively reinforced olfactory conditioning has been widely employed to identify learning and memory genes, signal transduction pathways and neural circuitry in Drosophila. To delineate the molecular and cellular processes underlying reward-mediated learning and memory, we developed a novel assay system for positively reinforced olfactory conditioning. In this assay, flies were involuntarily exposed to the appetitive unconditioned stimulus sucrose along with a conditioned stimulus odour during training and their preference for the odour previously associated with sucrose was measured to assess learning and memory capacities. After one training session, wild-type Canton S flies displayed reliable performance, which was enhanced after two training cycles with 1-min or 15-min inter-training intervals. Higher performance scores were also obtained with increasing sucrose concentration. Memory in Canton S flies decayed slowly when measured at 30 min, 1 h and 3 h after training; whereas, it had declined significantly at 6 h and 12 h post-training. When learning mutant t,,h flies, which are deficient in octopamine, were challenged, they exhibited poor performance, validating the utility of this assay. As the Drosophila model offers vast genetic and transgenic resources, the new appetitive conditioning described here provides a useful tool with which to elucidate the molecular and cellular underpinnings of reward learning and memory. Similar to negatively reinforced conditioning, this reward conditioning represents classical olfactory conditioning. Thus, comparative analyses of learning and memory mutants in two assays may help identify the molecular and cellular components that are specific to the unconditioned stimulus information used in conditioning. [source]