Graded Encoding of Food Odor Value in the Drosophila Brain

PubMed Central

Beshel, Jennifer

2013-01-01

Odors are highly evocative, yet how and where in the brain odors derive meaning remains unknown. Our analysis of the Drosophila brain extends the role of a small number of hunger-sensing neurons to include food-odor value representation. In vivo two-photon calcium imaging shows the amplitude of food odor-evoked activity in neurons expressing Drosophila neuropeptide F (dNPF), the neuropeptide Y homolog, strongly correlates with food-odor attractiveness. Hunger elevates neural and behavioral responses to food odors only, although food odors that elicit attraction in the fed state also evoke heightened dNPF activity in fed flies. Inactivation of a subset of dNPF-expressing neurons or silencing dNPF receptors abolishes food-odor attractiveness, whereas genetically enhanced dNPF activity not only increases food-odor attractiveness but promotes attraction to aversive odors. Varying the amount of presented odor produces matching graded neural and behavioral curves, which can function to predict preference between odors. We thus demonstrate a possible motivationally scaled neural “value signal” accessible from uniquely identifiable cells. PMID:24089477

Odorant Metabolism Analysis by an Automated Ex Vivo Headspace Gas-Chromatography Method.

PubMed

Faure, Philippe; Legendre, Arièle; Hanser, Hassan-Ismail; Andriot, Isabelle; Artur, Yves; Guichard, Elisabeth; Coureaud, Gérard; Heydel, Jean-Marie

2016-01-01

In the olfactory epithelium (OE), odorant metabolizing enzymes have the dual function of volatile component detoxification and active clearance of odorants from the perireceptor environment to respectively maintain the integrity of the tissues and the sensitivity of the detection. Although emphasized by recent studies, this enzymatic mechanism is poorly documented in mammals. Thus, olfactory metabolism has been characterized mainly in vitro and for a limited number of odorants. The automated ex vivo headspace gas-chromatography method that was developed here was validated to account for odorant olfactory metabolism. This method easily permits the measurement of the fate of an odorant in the OE environment, taking into account the odorant gaseous state and the cellular structure of the tissue, under experimental conditions close to physiological conditions and with a high reproducibility. We confirmed here our previous results showing that a high olfactory metabolizing activity of the mammary pheromone may be necessary to maintain a high level of sensitivity toward this molecule, which is critical for newborn rabbit survival. More generally, the method that is presented here may permit the screening of odorants metabolism alone or in mixture or studying the impact of aging, pathology, polymorphism or inhibitors on odorant metabolism. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

High hunger state increases olfactory sensitivity to neutral but not food odors.

PubMed

Stafford, Lorenzo D; Welbeck, Kimberley

2011-01-01

Understanding how hunger state relates to olfactory sensitivity has become more urgent due to their possible role in obesity. In 2 studies (within-subjects: n = 24, between-subjects: n = 40), participants were provided with lunch before (satiated state) or after (nonsatiated state) testing and completed a standardized olfactory threshold test to a neutral odor (Experiments 1 and 2) and discrimination test to a food odor (Experiment 2). Experiment 1 revealed that olfactory sensitivity was greater in the nonsatiated versus satiated state, with additionally increased sensitivity for the low body mass index (BMI) compared with high BMI group. Experiment 2 replicated this effect for neutral odors, but in the case of food odors, those in a satiated state had greater acuity. Additionally, whereas the high BMI group had higher acuity to food odors in the satiated versus nonsatiated state, no such differences were found for the low BMI group. The research here is the first to demonstrate how olfactory acuity changes as a function of hunger state and relatedness of odor to food and that BMI can predict differences in olfactory sensitivity.

A spiking neural network model of self-organized pattern recognition in the early mammalian olfactory system.

PubMed

Kaplan, Bernhard A; Lansner, Anders

2014-01-01

Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin-Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian-Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian-Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures.

A spiking neural network model of self-organized pattern recognition in the early mammalian olfactory system

PubMed Central

Kaplan, Bernhard A.; Lansner, Anders

2014-01-01

Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin–Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian–Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian–Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures. PMID:24570657

Multivariate prediction of odor from pig production based on in-situ measurement of odorants

NASA Astrophysics Data System (ADS)

Hansen, Michael J.; Jonassen, Kristoffer E. N.; Løkke, Mette Marie; Adamsen, Anders Peter S.; Feilberg, Anders

2016-06-01

The aim of the present study was to estimate a prediction model for odor from pig production facilities based on measurements of odorants by Proton-Transfer-Reaction Mass spectrometry (PTR-MS). Odor measurements were performed at four different pig production facilities with and without odor abatement technologies using a newly developed mobile odor laboratory equipped with a PTR-MS for measuring odorants and an olfactometer for measuring the odor concentration by human panelists. A total of 115 odor measurements were carried out in the mobile laboratory and simultaneously air samples were collected in Nalophan bags and analyzed at accredited laboratories after 24 h. The dataset was divided into a calibration dataset containing 94 samples and a validation dataset containing 21 samples. The prediction model based on the measurements in the mobile laboratory was able to explain 74% of the variation in the odor concentration based on odorants, whereas the prediction models based on odor measurements with bag samples explained only 46-57%. This study is the first application of direct field olfactometry to livestock odor and emphasizes the importance of avoiding any bias from sample storage in studies of odor-odorant relationships. Application of the model on the validation dataset gave a high correlation between predicted and measured odor concentration (R2 = 0.77). Significant odorants in the prediction models include phenols and indoles. In conclusion, measurements of odorants on-site in pig production facilities is an alternative to dynamic olfactometry that can be applied for measuring odor from pig houses and the effects of odor abatement technologies.

Characterizing the Smell of Marijuana by Odor Impact of Volatile Compounds: An Application of Simultaneous Chemical and Sensory Analysis

PubMed Central

2015-01-01

Recent US legislation permitting recreational use of marijuana in certain states brings the use of marijuana odor as probable cause for search and seizure to the forefront of forensic science, once again. This study showed the use of solid-phase microextraction with multidimensional gas chromatography—mass spectrometry and simultaneous human olfaction to characterize the total aroma of marijuana. The application of odor activity analysis offers an explanation as to why high volatile chemical concentration does not equate to most potent odor impact of a certain compound. This suggests that more attention should be focused on highly odorous compounds typically present in low concentrations, such as nonanal, decanol, o-cymene, benzaldehyde, which have more potent odor impact than previously reported marijuana headspace volatiles. PMID:26657499

Fresh squeezed orange juice odor: a review.

PubMed

Perez-Cacho, Pilar Ruiz; Rouseff, Russell L

2008-08-01

Fresh orange juice is a highly desirable but unstable product. This review examines analytical findings, odor activity, and variations due to cultivar, sampling methods, manner of juicing, plus possible enzymatic and microbial artifacts. Initial attempts to characterize orange juice odor were based on volatile quantitation and overemphasized the importance of high concentration volatiles. Although over 300 volatiles have been reported from GC-MS analytical studies, this review presents 36 consensus aroma active components from GC-olfactometry studies consisting of 14 aldehydes, 7 esters, 5 terpenes, 6 alcohols, and 4 ketones. Most are trace (microg/L) components. (+)-Limonene is an essential component in orange juice odor although its exact function is still uncertain. Total amounts of volatiles in mechanically squeezed juices are three to 10 times greater than hand-squeezed juices because of elevated peel oil levels. Elevated peel oil changes the relative proportion of several key odorants. Odor active components from solvent extraction studies differ from those collected using headspace techniques as they include volatiles with low vapor pressure such as vanillin. Some reported odorants such as 2,3-butanedione are microbial contamination artifacts. Orange juice odor models confirm that fresh orange aroma is complex as the most successful models contain 23 odorants.

Psychology of Fragrance Use: Perception of Individual Odor and Perfume Blends Reveals a Mechanism for Idiosyncratic Effects on Fragrance Choice

PubMed Central

Lenochová, Pavlína; Vohnoutová, Pavla; Roberts, S. Craig; Oberzaucher, Elisabeth; Grammer, Karl; Havlíček, Jan

2012-01-01

Cross-culturally, fragrances are used to modulate body odor, but the psychology of fragrance choice has been largely overlooked. The prevalent view is that fragrances mask an individual's body odor and improve its pleasantness. In two experiments, we found positive effects of perfume on body odor perception. Importantly, however, this was modulated by significant interactions with individual odor donors. Fragrances thus appear to interact with body odor, creating an individually-specific odor mixture. In a third experiment, the odor mixture of an individual's body odor and their preferred perfume was perceived as more pleasant than a blend of the same body odor with a randomly-allocated perfume, even when there was no difference in pleasantness between the perfumes. This indicates that fragrance use extends beyond simple masking effects and that people choose perfumes that interact well with their own odor. Our results provide an explanation for the highly individual nature of perfume choice. PMID:22470479

Psychology of fragrance use: perception of individual odor and perfume blends reveals a mechanism for idiosyncratic effects on fragrance choice.

PubMed

Lenochová, Pavlína; Vohnoutová, Pavla; Roberts, S Craig; Oberzaucher, Elisabeth; Grammer, Karl; Havlíček, Jan

2012-01-01

Cross-culturally, fragrances are used to modulate body odor, but the psychology of fragrance choice has been largely overlooked. The prevalent view is that fragrances mask an individual's body odor and improve its pleasantness. In two experiments, we found positive effects of perfume on body odor perception. Importantly, however, this was modulated by significant interactions with individual odor donors. Fragrances thus appear to interact with body odor, creating an individually-specific odor mixture. In a third experiment, the odor mixture of an individual's body odor and their preferred perfume was perceived as more pleasant than a blend of the same body odor with a randomly-allocated perfume, even when there was no difference in pleasantness between the perfumes. This indicates that fragrance use extends beyond simple masking effects and that people choose perfumes that interact well with their own odor. Our results provide an explanation for the highly individual nature of perfume choice.

Visualizing the engram: learning stabilizes odor representations in the olfactory network.

PubMed

Shakhawat, Amin M D; Gheidi, Ali; Hou, Qinlong; Dhillon, Sandeep K; Marrone, Diano F; Harley, Carolyn W; Yuan, Qi

2014-11-12

The nature of memory is a central issue in neuroscience. How does our representation of the world change with learning and experience? Here we use the transcription of Arc mRNA, which permits probing the neural representations of temporally separated events, to address this in a well characterized odor learning model. Rat pups readily associate odor with maternal care. In pups, the lateralized olfactory networks are independent, permitting separate training and within-subject control. We use multiday training to create an enduring memory of peppermint odor. Training stabilized rewarded, but not nonrewarded, odor representations in both mitral cells and associated granule cells of the olfactory bulb and in the pyramidal cells of the anterior piriform cortex. An enlarged core of stable, likely highly active neurons represent rewarded odor at both stages of the olfactory network. Odor representations in anterior piriform cortex were sparser than typical in adult rat and did not enlarge with learning. This sparser representation of odor is congruent with the maturation of lateral olfactory tract input in rat pups. Cortical representations elsewhere have been shown to be highly variable in electrophysiological experiments, suggesting brains operate normally using dynamic and network-modulated representations. The olfactory cortical representations here are consistent with the generalized associative model of sparse variable cortical representation, as normal responses to repeated odors were highly variable (∼70% of the cells change as indexed by Arc). Learning and memory modified rewarded odor ensembles to increase stability in a core representational component. Copyright © 2014 the authors 0270-6474/14/3415394-08$15.00/0.

Sensory Preconditioning in Newborn Rabbits: From Common to Distinct Odor Memories

ERIC Educational Resources Information Center

Coureaud, Gerard; Tourat, Audrey; Ferreira, Guillaume

2013-01-01

This study evaluated whether olfactory preconditioning is functional in newborn rabbits and based on joined or independent memory of odorants. First, after exposure to odorants A+B, the conditioning of A led to high responsiveness to odorant B. Second, responsiveness to B persisted after amnesia of A. Third, preconditioning was also functional…

Odor-Active Compounds in the Special Flavor Hops Huell Melon and Polaris.

PubMed

Neiens, Silva D; Steinhaus, Martin

2018-02-14

The volatiles isolated from samples of the special flavor hop varieties, Huell Melon and Polaris, and from the aroma hop variety, Hallertau Tradition, by solvent extraction and solvent-assisted flavor evaporation (SAFE) were subjected to a comparative aroma extract dilution analysis (cAEDA), which resulted in 46 odor-active compounds in the flavor dilution (FD) factor range of 16 to 2048. On the basis of high FD factors, myrcene, (3R)-linalool, and 2- and 3-methylbutanoic acid were confirmed as important variety-independent hop odorants. (1R,4S)-Calamenene was identified for the first time as an odor-active compound in hops. Clear differences in the FD factors and their subsequent objectification by stable isotope dilution quantitation suggested that high concentrations of the esters ethyl 2-methylbutanoate, ethyl 2-methylpropanoate, and propyl 2-methylbutanoate cause the characteristic fruity, cantaloupe-like odor note in Huell Melon hops, whereas the fruity and minty odor notes in Polaris are associated with high amounts of 3-methylbutyl acetate and 1,8-cineole.

Honeybees Learn Odour Mixtures via a Selection of Key Odorants

PubMed Central

Reinhard, Judith; Sinclair, Michael; Srinivasan, Mandyam V.; Claudianos, Charles

2010-01-01

Background The honeybee has to detect, process and learn numerous complex odours from her natural environment on a daily basis. Most of these odours are floral scents, which are mixtures of dozens of different odorants. To date, it is still unclear how the bee brain unravels the complex information contained in scent mixtures. Methodology/Principal Findings This study investigates learning of complex odour mixtures in honeybees using a simple olfactory conditioning procedure, the Proboscis-Extension-Reflex (PER) paradigm. Restrained honeybees were trained to three scent mixtures composed of 14 floral odorants each, and then tested with the individual odorants of each mixture. Bees did not respond to all odorants of a mixture equally: They responded well to a selection of key odorants, which were unique for each of the three scent mixtures. Bees showed less or very little response to the other odorants of the mixtures. The bees' response to mixtures composed of only the key odorants was as good as to the original mixtures of 14 odorants. A mixture composed of the other, non-key-odorants elicited a significantly lower response. Neither an odorant's volatility or molecular structure, nor learning efficiencies for individual odorants affected whether an odorant became a key odorant for a particular mixture. Odorant concentration had a positive effect, with odorants at high concentration likely to become key odorants. Conclusions/Significance Our study suggests that the brain processes complex scent mixtures by predominantly learning information from selected key odorants. Our observations on key odorant learning lend significant support to previous work on olfactory learning and mixture processing in honeybees. PMID:20161714

Numerical modeling of turbulent and laminar airflow and odorant transport during sniffing in the human and rat nose.

PubMed

Zhao, Kai; Dalton, Pamela; Yang, Geoffery C; Scherer, Peter W

2006-02-01

Human sniffing behavior usually involves bouts of short, high flow rate inhalation (>300 ml/s through each nostril) with mostly turbulent airflow. This has often been characterized as a factor enabling higher amounts of odorant to deposit onto olfactory mucosa than for laminar airflow and thereby aid in olfactory detection. Using computational fluid dynamics human nasal cavity models, however, we found essentially no difference in predicted olfactory odorant flux (g/cm2 s) for turbulent versus laminar flow for total nasal flow rates between 300 and 1000 ml/s and for odorants of quite different mucosal solubility. This lack of difference was shown to be due to the much higher resistance to lateral odorant mass transport in the mucosal nasal airway wall than in the air phase. The simulation also revealed that the increase in airflow rate during sniffing can increase odorant uptake flux to the nasal/olfactory mucosa but lower the cumulative total uptake in the olfactory region when the inspired air/odorant volume was held fixed, which is consistent with the observation that sniff duration may be more important than sniff strength for optimizing olfactory detection. In contrast, in rats, sniffing involves high-frequency bouts of both inhalation and exhalation with laminar airflow. In rat nose odorant uptake simulations, it was observed that odorant deposition was highly dependent on solubility and correlated with the locations of different types of receptors.

Determination of urine-derived odorous compounds in a source separation sanitation system.

PubMed

Liu, Bianxia; Giannis, Apostolos; Chen, Ailu; Zhang, Jiefeng; Chang, Victor W C; Wang, Jing-Yuan

2017-02-01

Source separation sanitation systems have attracted more and more attention recently. However, separate urine collection and treatment could induce odor issues, especially in large scale application. In order to avoid such issues, it is necessary to monitor the odor related compounds that might be generated during urine storage. This study investigated the odorous compounds that emitted from source-separated human urine under different hydrolysis conditions. Batch experiments were conducted to investigate the effect of temperature, stale/fresh urine ratio and urine dilution on odor emissions. It was found that ammonia, dimethyl disulfide, allyl methyl sulfide and 4-heptanone were the main odorous compounds generated from human urine, with headspace concentrations hundreds of times higher than their respective odor thresholds. Furthermore, the high temperature accelerated urine hydrolysis and liquid-gas mass transfer, resulting a remarkable increase of odor emissions from the urine solution. The addition of stale urine enhanced urine hydrolysis and expedited odor emissions. On the contrary, diluted urine emitted less odorous compounds ascribed to reduced concentrations of odorant precursors. In addition, this study quantified the odor emissions and revealed the constraints of urine source separation in real-world applications. To address the odor issue, several control strategies are recommended for odor mitigation or elimination from an engineering perspective. Copyright © 2016. Published by Elsevier B.V.

Sedative effects of the jasmine tea odor and (R)-(-)-linalool, one of its major odor components, on autonomic nerve activity and mood states.

PubMed

Kuroda, Kyoko; Inoue, Naohiko; Ito, Yuriko; Kubota, Kikue; Sugimoto, Akio; Kakuda, Takami; Fushiki, Tohru

2005-10-01

We investigated the effects of the odor of jasmine tea on autonomic nerve activity and mood states in a total of 24 healthy volunteers. We used the odor of jasmine tea at the lowest concentration that could be detected by each subject but that did not elicit any psychological effects. R-R intervals and the POMS test were measured before and after inhalation of the odors for 5 min. Both jasmine tea and lavender odors at perceived similar intensity caused significant decreases in heart rate and significant increases in spectral integrated values at high-frequency component in comparison with the control (P < 0.05). In the POMS tests, these odors produced calm and vigorous mood states. We also examined the effects of (R)-(-)-linalool, one of its major odor components, at the same concentration as in the tea, and (S)-(+)-linalool. Only (R)-(-)-linalool elicited a significant decrease in heart rate (P < 0.05) and an increase in high-frequency component in comparison with the controls, and produced calm and vigorous mood states. Thus, the low intensity of jasmine tea odor has sedative effects on both autonomic nerve activity and mood states, and (R)-(-)-linalool, one of its components, can mimic these effects.

Novel cell-based odorant sensor elements based on insect odorant receptors.

PubMed

Mitsuno, Hidefumi; Sakurai, Takeshi; Namiki, Shigehiro; Mitsuhashi, Hiroyuki; Kanzaki, Ryohei

2015-03-15

Development of cell-based odorant sensor elements combined not only high degree of sensitivity and selectivity but also long-term stability is crucial for their practical applications. Here we report the development of a novel cell-based odorant sensor element that sensitively and selectively detects odorants and displays increased fluorescent intensities over a long period of time. Our odorant sensor elements, based on Sf21 cell lines expressing insect odorant receptors, are sensitive to the level of several tens of parts per billion in solution, can selectively distinguish between different types of odorants based on the odorant selectivity intrinsic to the expressed receptors, and have response times of approximately 13s. Specifically, with the use of Sf21 cells and insect odorant receptors, we demonstrated that the established cell lines stably expressing insect odorant receptors are able to detect odorants with consistent responsiveness for at least 2 months, thus exceeding the short life-span normally associated with cell-based sensors. We also demonstrated the development of a compact odorant sensor chip by integrating the established insect cell lines into a microfluidic chip. The methodology we established in this study, in conjunction with the large repertoire of insect odorant receptors, will aid in the development of practical cell-based odorant sensors for various applications, including food administration and health management. Copyright © 2014 Elsevier B.V. All rights reserved.

Odor Learning and Its Experience-Dependent Modulation in the South American Native Bumblebee Bombus atratus (Hymenoptera: Apidae).

PubMed

Palottini, Florencia; Estravis Barcala, María C; Farina, Walter M

2018-01-01

Learning about olfactory stimuli is essential in bumblebees' life since it is involved in orientation, recognition of nest sites, foraging efficiency and food yield for the colony as a whole. To evaluate associative learning abilities in bees under controlled environmental conditions, the proboscis extension response (PER) assay is a well-established method used in honey bees, stingless bees and successfully adapted to bumblebees of the genus Bombus . However, studies on the learning capacity of Bombus atratus (Hymenoptera: Apidae), one of the most abundant native species in South America, are non-existent. In this study, we examined the cognitive abilities of worker bees of this species, carrying out an olfactory PER conditioning experiment. Bumblebees were able to learn a pure odor when it was presented in paired association with sugared reward, but not when odor and reward were presented in an unpaired manner. Furthermore, if the bees were preexposed to the conditioned odor, the results differed depending on the presence of the scent either as a volatile in the rearing environment or diluted in the food. A decrement in learning performance results from the non-reinforced pre-exposure to the to-be-conditioned odor, showing a latent inhibition phenomenon. However, if the conditioned odor has been previously offered diluted in sugared reward, the food odor acts as a stimulus that improves the learning performance during PER conditioning. The native bumblebee B. atratus is thus a new hymenopteran species capable of being trained under controlled experimental conditions. Since it is an insect increasingly reared for pollination service, this knowledge could be useful in its management in crops.

Odor Learning and Its Experience-Dependent Modulation in the South American Native Bumblebee Bombus atratus (Hymenoptera: Apidae)

PubMed Central

Palottini, Florencia; Estravis Barcala, María C.; Farina, Walter M.

2018-01-01

Learning about olfactory stimuli is essential in bumblebees’ life since it is involved in orientation, recognition of nest sites, foraging efficiency and food yield for the colony as a whole. To evaluate associative learning abilities in bees under controlled environmental conditions, the proboscis extension response (PER) assay is a well-established method used in honey bees, stingless bees and successfully adapted to bumblebees of the genus Bombus. However, studies on the learning capacity of Bombus atratus (Hymenoptera: Apidae), one of the most abundant native species in South America, are non-existent. In this study, we examined the cognitive abilities of worker bees of this species, carrying out an olfactory PER conditioning experiment. Bumblebees were able to learn a pure odor when it was presented in paired association with sugared reward, but not when odor and reward were presented in an unpaired manner. Furthermore, if the bees were preexposed to the conditioned odor, the results differed depending on the presence of the scent either as a volatile in the rearing environment or diluted in the food. A decrement in learning performance results from the non-reinforced pre-exposure to the to-be-conditioned odor, showing a latent inhibition phenomenon. However, if the conditioned odor has been previously offered diluted in sugared reward, the food odor acts as a stimulus that improves the learning performance during PER conditioning. The native bumblebee B. atratus is thus a new hymenopteran species capable of being trained under controlled experimental conditions. Since it is an insect increasingly reared for pollination service, this knowledge could be useful in its management in crops. PMID:29755391

Characterization and control of odorous gases at a landfill site: a case study in Hangzhou, China.

PubMed

Ying, Ding; Chuanyu, Cai; Bin, Hu; Yueen, Xu; Xuejuan, Zheng; Yingxu, Chen; Weixiang, Wu

2012-02-01

Municipal solid waste (MSW) landfills are one of the major sources of offensive odors potentially creating annoyance in adjacent communities. At the end of May 2007, an odor pollution incident occurred at the Tianziling landfill site, Hangzhou, China, where the residents lodged complaints about the intense odor from the landfill, which drew a significant attention from the government. In this study, ambient air monitoring was conducted at the Tianziling landfill site. The main odor composition of the gas samples collected on June 1st 2007 and the reduction of various odorous gases from the samples collected on June 1st 2009 due to the applied odor control techniques were determined using gas chromatography-mass spectrometry (GC-MS). In addition, variations of primary odorous gaseous (NH(3) and H(2)S) concentrations at different locations in the landfill site from July 2007 to June 2009 were also investigated by using classical spectrophotometric methods. Results showed that a total of 68 volatile compounds were identified among which H(2)S (56.58-579.84 μg/m(3)) and NH(3) (520-4460 μg/m(3)) were the notable odor components contributing to 4.47-10.92% and 83.91-93.94% of total concentrations, respectively. Similar spatial and temporal shifts of H(2)S and NH(3) concentrations were observed and were significantly affected by environmental factors including temperature, air pressure and wind direction. Odor pollution was worse when high temperature, high humidity, low air pressure, and southeast, northeast or east wind appeared. Moreover, the environmental sampling points of the dumping area and the leachate treatment plant were found to be the main odor sources at the Tianziling landfill site. The odor control technologies used in this project had a good mitigating effect on the primary odorous compounds. This study provides long-term valuable information concerning the characteristics and control of odors at landfill sites in a long run. Copyright © 2011 Elsevier Ltd. All rights reserved.

How the brain assigns a neural tag to arbitrary points in a high-dimensional space

NASA Astrophysics Data System (ADS)

Stevens, Charles

Brains in almost all organisms need to deal with very complex stimuli. For example, most mammals are very good at face recognition, and faces are very complex objects indeed. For example, modern face recognition software represents a face as a point in a 10,000 dimensional space. Every human must be able to learn to recognize any of the 7 billion faces in the world, and can recognize familiar faces after a display of the face is viewed for only a few hundred milliseconds. Because we do not understand how faces are assigned locations in a high-dimensional space by the brain, attacking the problem of how face recognition is accomplished is very difficult. But a much easier problem of the same sort can be studied for odor recognition. For the mouse, each odor is assigned a point in a 1000 dimensional space, and the fruit fly assigns any odor a location in only a 50 dimensional space. A fly has about 50 distinct types of odorant receptor neurons (ORNs), each of which produce nerve impulses at a specific rate for each different odor. This pattern of firing produced across 50 ORNs is called `a combinatorial odor code', and this code assigns every odor a point in a 50 dimensional space that is used to identify the odor. In order to learn the odor, the brain must alter the strength of synapses. The combinatorial code cannot itself by used to change synaptic strength because all odors use same neurons to form the code, and so all synapses would be changed for any odor and the odors could not be distinguished. In order to learn an odor, the brain must assign a set of neurons - the odor tag - that have the property that these neurons (1) should make use of all of the information available about the odor, and (2) insure that any two tags overlap as little as possible (so one odor does not modify synapses used by other odors). In the talk, I will explain how the olfactory system of both the fruit fly and the mouse produce a tag for each odor that has these two properties. Supported by NSF.

Sampling Odor Substances by Mist-Cyclone System

NASA Astrophysics Data System (ADS)

Matsubara, Osamu; Jiang, Zhiheng; Toyama, Shigeki

2009-05-01

Many techniques have been developed to measure odor substances. However most of those methods are based on using aquatic solutions(1),(2). Many odor substances specifically at low density situation, are difficult to dissolve into water. To absorb odor substances and obtain highest concentration solutions are key problems for olfactory systems. By blowing odor substances contained air mixture through mist of water and then separating the liquid from two-phases fluid with a cyclone unit a high concentration solution was obtained.

Tracking fluid-borne odors in diverse and dynamic environments using multiple sensory mechanisms

NASA Astrophysics Data System (ADS)

Taylor, Brian Kyle

The ability to locate odor sources in different types of environments (i.e. diverse) and environments that change radically during the mission (i.e., dynamic) is essential. While many engineered odor tracking systems have been developed, they appear to be designed for a particular environment (e.g., strong or low flow). In field conditions, agents may encounter both. Insect olfactory orientation studies show that several animals can locate odor sources in both high and low flow environments, and environments where the wind vanishes during tracking behavior. Furthermore, animals use multi-modal sensing, including olfaction, vision and touch to localize a source. This work uses simulated and hardware environments to explore how engineered systems can maintain wind-driven tracking behavior in diverse and dynamic environments. The simulation uses olfaction, vision and tactile attributes to track and localize a source in the following environments: high flow, low flow, and transition from high to low flow (i.e., Wind Stop). The hardware platform tests two disparate tracking strategies (including the simulated strategy) in an environment that transitions from strong to low flow. Results indicate that using a remembered wind direction post wind-shutoff is a viable way to maintain wind-driven tracking behavior in a wind stop environment, which can help bridge the gap between high flow and low flow strategies. Also, multi-modal sensing with tactile attributes, vision and olfaction helps a vehicle to localize a source. In addition to engineered systems, the moth Manduca sexta is challenged to track in the following environments: Wind and Odor, Wind Stop, Odor and No Wind, No Odor and No Wind to gain a better understanding of animal behavior in these environments. Results show that contrary to previous studies of different moth species, M. sexta does not generally maintain its wind-driven tracking behavior post-wind shutoff, but instead executes a stereotyped sequence of maneuvers followed by odor-modulated undirected exploration of its environment. In the Odor and No Wind environment, animals become biased towards the area of the arena where odor is located compared to the No Odor and No Wind environment. Robot and animal results are compared to learn more about both.

A salty-congruent odor enhances saltiness: functional magnetic resonance imaging study.

PubMed

Seo, Han-Seok; Iannilli, Emilia; Hummel, Cornelia; Okazaki, Yoshiro; Buschhüter, Dorothee; Gerber, Johannes; Krammer, Gerhard E; van Lengerich, Bernhard; Hummel, Thomas

2013-01-01

Excessive intake of dietary salt (sodium chloride) may increase the risk of chronic diseases. Accordingly, various strategies to reduce salt intake have been conducted. This study aimed to investigate whether a salty-congruent odor can enhance saltiness on the basis of psychophysical (Experiment 1) and neuroanatomical levels (Experiment 2). In Experiment 1, after receiving one of six stimulus conditions: three odor conditions (odorless air, congruent, or incongruent odor) by two concentrations (low or high) of either salty or sweet taste solution, participants were asked to rate taste intensity and pleasantness. In Experiment 2, participants received the same stimuli during the functional magnetic resonance imaging scan. In Experiment 1, compared with an incongruent odor and/or odorless air, a congruent odor enhanced not only taste intensity but also either pleasantness of sweetness or unpleasantness of saltiness. In Experiment 2, a salty-congruent combination of odor and taste produced significantly higher neuronal activations in brain regions associated with odor-taste integration (e.g., insula, frontal operculum, anterior cingulate cortex, and orbitofrontal cortex) than an incongruent combination and/or odorless air with taste solution. In addition, the congruent odor-induced saltiness enhancement was more pronounced in the low-concentrated tastant than in the high-concentrated one. In conclusion, this study demonstrates the congruent odor-induced saltiness enhancement on the basis of psychophysical and neuroanatomical results. These findings support an alternative strategy to reduce excessive salt intake by adding salty-congruent aroma to sodium reduced food. However, there are open questions regarding the salty-congruent odor-induced taste unpleasantness. Copyright © 2011 Wiley Periodicals, Inc.

Cell-Based Odorant Sensor Array for Odor Discrimination Based on Insect Odorant Receptors.

PubMed

Termtanasombat, Maneerat; Mitsuno, Hidefumi; Misawa, Nobuo; Yamahira, Shinya; Sakurai, Takeshi; Yamaguchi, Satoshi; Nagamune, Teruyuki; Kanzaki, Ryohei

2016-07-01

The olfactory system of living organisms can accurately discriminate numerous odors by recognizing the pattern of activation of several odorant receptors (ORs). Thus, development of an odorant sensor array based on multiple ORs presents the possibility of mimicking biological odor discrimination mechanisms. Recently, we developed novel odorant sensor elements with high sensitivity and selectivity based on insect OR-expressing Sf21 cells that respond to target odorants by displaying increased fluorescence intensity. Here we introduce the development of an odorant sensor array composed of several Sf21 cell lines expressing different ORs. In this study, an array pattern of four cell lines expressing Or13a, Or56a, BmOR1, and BmOR3 was successfully created using a patterned polydimethylsiloxane film template and cell-immobilizing reagents, termed biocompatible anchor for membrane (BAM). We demonstrated that BAM could create a clear pattern of Sf21 sensor cells without impacting their odorant-sensing performance. Our sensor array showed odorant-specific response patterns toward both odorant mixtures and single odorant stimuli, allowing us to visualize the presence of 1-octen-3-ol, geosmin, bombykol, and bombykal as an increased fluorescence intensity in the region of Or13a, Or56a, BmOR1, and BmOR3 cell lines, respectively. Therefore, we successfully developed a new methodology for creating a cell-based odorant sensor array that enables us to discriminate multiple target odorants. Our method might be expanded into the development of an odorant sensor capable of detecting a large range of environmental odorants that might become a promising tool used in various applications including the study of insect semiochemicals and food contamination.

Odor Coding by a Mammalian Receptor Repertoire

PubMed Central

Saito, Harumi; Chi, Qiuyi; Zhuang, Hanyi; Matsunami, Hiro; Mainland, Joel D.

2009-01-01

Deciphering olfactory encoding requires a thorough description of the ligands that activate each odorant receptor (OR). In mammalian systems, however, ligands are known for fewer than 50 of over 1400 human and mouse ORs, greatly limiting our understanding of olfactory coding. We performed high-throughput screening of 93 odorants against 464 ORs expressed in heterologous cells and identified agonists for 52 mouse and 10 human ORs. We used the resulting interaction profiles to develop a predictive model relating physicochemical odorant properties, OR sequences, and their interactions. Our results provide a basis for translating odorants into receptor neuron responses and unraveling mammalian odor coding. PMID:19261596

A Robot Equipped with a High-Speed LSPR Gas Sensor Module for Collecting Spatial Odor Information from On-Ground Invisible Odor Sources.

PubMed

Yang, Zhongyuan; Sassa, Fumihiro; Hayashi, Kenshi

2018-06-22

Improving the efficiency of detecting the spatial distribution of gas information with a mobile robot is a great challenge that requires rapid sample collection, which is basically determined by the speed of operation of gas sensors. The present work developed a robot equipped with a high-speed gas sensor module based on localized surface plasmon resonance. The sensor module is designed to sample gases from an on-ground odor source, such as a footprint material or artificial odor marker, via a fine sampling tubing. The tip of the sampling tubing was placed close to the ground to reduce the sampling time and the effect of natural gas diffusion. On-ground ethanol odor sources were detected by the robot at high resolution (i.e., 2.5 cm when the robot moved at 10 cm/s), and the reading of gas information was demonstrated experimentally. This work may help in the development of environmental sensing robots, such as the development of odor source mapping and multirobot systems with pheromone tracing.

Honey bee odorant-binding protein 14: effects on thermal stability upon odorant binding revealed by FT-IR spectroscopy and CD measurements.

PubMed

Schwaighofer, Andreas; Kotlowski, Caroline; Araman, Can; Chu, Nam; Mastrogiacomo, Rosa; Becker, Christian; Pelosi, Paolo; Knoll, Wolfgang; Larisika, Melanie; Nowak, Christoph

2014-03-01

In the present work, we study the effect of odorant binding on the thermal stability of honey bee (Apis mellifera L.) odorant-binding protein 14. Thermal denaturation of the protein in the absence and presence of different odorant molecules was monitored by Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD). FT-IR spectra show characteristic bands for intermolecular aggregation through the formation of intermolecular β-sheets during the heating process. Transition temperatures in the FT-IR spectra were evaluated using moving-window 2D correlation maps and confirmed by CD measurements. The obtained results reveal an increase of the denaturation temperature of the protein when bound to an odorant molecule. We could also discriminate between high- and low-affinity odorants by determining transition temperatures, as demonstrated independently by the two applied methodologies. The increased thermal stability in the presence of ligands is attributed to a stabilizing effect of non-covalent interactions between odorant-binding protein 14 and the odorant molecule.

Introducing Computational Fluid Dynamics Simulation into Olfactory Display

NASA Astrophysics Data System (ADS)

Ishida, Hiroshi; Yoshida, Hitoshi; Nakamoto, Takamichi

An olfactory display is a device that delivers various odors to the user's nose. It can be used to add special effects to movies and games by releasing odors relevant to the scenes shown on the screen. In order to provide high-presence olfactory stimuli to the users, the display must be able to generate realistic odors with appropriate concentrations in a timely manner together with visual and audio playbacks. In this paper, we propose to use computational fluid dynamics (CFD) simulations in conjunction with the olfactory display. Odor molecules released from their source are transported mainly by turbulent flow, and their behavior can be extremely complicated even in a simple indoor environment. In the proposed system, a CFD solver is employed to calculate the airflow field and the odor dispersal in the given environment. An odor blender is used to generate the odor with the concentration determined based on the calculated odor distribution. Experimental results on presenting odor stimuli synchronously with movie clips show the effectiveness of the proposed system.

Dense encoding of natural odorants by ensembles of sparsely activated neurons in the olfactory bulb

PubMed Central

Gschwend, Olivier; Beroud, Jonathan; Vincis, Roberto; Rodriguez, Ivan; Carleton, Alan

2016-01-01

Sensory information undergoes substantial transformation along sensory pathways, usually encompassing sparsening of activity. In the olfactory bulb, though natural odorants evoke dense glomerular input maps, mitral and tufted (M/T) cells tuning is considered to be sparse because of highly odor-specific firing rate change. However, experiments used to draw this conclusion were either based on recordings performed in anesthetized preparations or used monomolecular odorants presented at arbitrary concentrations. In this study, we evaluated the lifetime and population sparseness evoked by natural odorants by capturing spike temporal patterning of neuronal assemblies instead of individual M/T tonic activity. Using functional imaging and tetrode recordings in awake mice, we show that natural odorants at their native concentrations are encoded by broad assemblies of M/T cells. While reducing odorant concentrations, we observed a reduced number of activated glomeruli representations and consequently a narrowing of M/T tuning curves. We conclude that natural odorants at their native concentrations recruit M/T cells with phasic rather than tonic activity. When encoding odorants in assemblies, M/T cells carry information about a vast number of odorants (lifetime sparseness). In addition, each natural odorant activates a broad M/T cell assembly (population sparseness). PMID:27824096

Integral approaches to wastewater treatment plant upgrading for odor prevention: Activated Sludge and Oxidized Ammonium Recycling.

PubMed

Estrada, José M; Kraakman, N J R; Lebrero, R; Muñoz, R

2015-11-01

Traditional physical/chemical end-of-the-pipe technologies for odor abatement are relatively expensive and present high environmental impacts. On the other hand, biotechnologies have recently emerged as cost-effective and environmentally friendly alternatives but are still limited by their investment costs and land requirements. A more desirable approach to odor control is the prevention of odorant formation before being released to the atmosphere, but limited information is available beyond good design and operational practices of the wastewater treatment process. The present paper reviews two widely applicable and economic alternatives for odor control, Activated Sludge Recycling (ASR) and Oxidized Ammonium Recycling (OAR), by discussing their fundamentals, key operating parameters and experience from the available pilot and field studies. Both technologies present high application potential using readily available plant by-products with a minimum plant upgrading, and low investment and operating costs, contributing to the sustainability and economic efficiency of odor control at wastewater treatment facilities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Elucidation of Thermally Induced Changes in Key Odorants of White Mustard Seeds (Sinapis alba L.) and Rapeseeds (Brassica napus L.) Using Molecular Sensory Science.

PubMed

Ortner, Eva; Granvogl, Michael; Schieberle, Peter

2016-11-02

Heat-processing of Brassica seeds led to the formation of a characteristic pleasant popcorn-like and coffee-like aroma impression compared to the mainly pea-like aroma of the corresponding raw seeds. To analyze this phenomenon on a molecular basis, raw and roasted white mustard seeds and rapeseeds were analyzed using the sensomics approach. Application of comparative aroma extract dilution analysis (cAEDA) and identification experiments to raw and roasted (140 °C, 30 min) mustard seeds revealed 36 odorants (all identified for the first time) and 47 odorants (41 newly identified), respectively. Twenty-seven odorants in raw and 43 odorants in roasted (140 °C, 60 min) rapeseeds were found, which were all described for the first time. Among the set of volatiles, 2-isopropyl-3-methoxypyrazine (earthy, pea-like) and 4-ethenyl-2-methoxyphenol (clove-like, smoky) showed high FD factors in both raw seeds. 4-Hydroxy-2,5-dimethylfuran-3(2H)-one (caramel-like), 2,3-diethyl-5-methylpyrazine (earthy), dimethyl trisulfide (cabbage-like), and 2-acetyl-1-pyrroline (popcorn-like) were present at high flavor dilution (FD) factors in both roasted Brassica seeds. Odorants, differing in cAEDA or showing high FD factors in at least one of the seeds, were quantitated by stable isotope dilution analysis (SIDA), followed by the calculation of odor activity values (OAVs) using odor thresholds determined in refined sunflower oil. Eighteen aroma compounds in raw and 28 in roasted mustard seeds as well as 14 in raw and 25 in roasted rapeseeds revealed OAVs ≥1. All four aroma recombinates, prepared by mixing the odorants showing OAVs ≥1 in their naturally occurring concentrations, showed a very good similarity with the original seeds and, thus, proved the successful characterization of the respective key odorants.

Odor Landscapes in Turbulent Environments

NASA Astrophysics Data System (ADS)

Celani, Antonio; Villermaux, Emmanuel; Vergassola, Massimo

2014-10-01

The olfactory system of male moths is exquisitely sensitive to pheromones emitted by females and transported in the environment by atmospheric turbulence. Moths respond to minute amounts of pheromones, and their behavior is sensitive to the fine-scale structure of turbulent plumes where pheromone concentration is detectible. The signal of pheromone whiffs is qualitatively known to be intermittent, yet quantitative characterization of its statistical properties is lacking. This challenging fluid dynamics problem is also relevant for entomology, neurobiology, and the technological design of olfactory stimulators aimed at reproducing physiological odor signals in well-controlled laboratory conditions. Here, we develop a Lagrangian approach to the transport of pheromones by turbulent flows and exploit it to predict the statistics of odor detection during olfactory searches. The theory yields explicit probability distributions for the intensity and the duration of pheromone detections, as well as their spacing in time. Predictions are favorably tested by using numerical simulations, laboratory experiments, and field data for the atmospheric surface layer. The resulting signal of odor detections lends itself to implementation with state-of-the-art technologies and quantifies the amount and the type of information that male moths can exploit during olfactory searches.

Insect odorant receptors are molecular targets of the insect repellent DEET.

PubMed

Ditzen, Mathias; Pellegrino, Maurizio; Vosshall, Leslie B

2008-03-28

DEET (N,N-diethyl-meta-toluamide) is the world's most widely used topical insect repellent, with broad effectiveness against most insects. Its mechanism of action and molecular target remain unknown. Here, we show that DEET blocks electrophysiological responses of olfactory sensory neurons to attractive odors in Anopheles gambiae and Drosophila melanogaster. DEET inhibits behavioral attraction to food odors in Drosophila, and this inhibition requires the highly conserved olfactory co-receptor OR83b. DEET inhibits odor-evoked currents mediated by the insect odorant receptor complex, comprising a ligand-binding subunit and OR83b. We conclude that DEET masks host odor by inhibiting subsets of heteromeric insect odorant receptors that require the OR83b co-receptor. The identification of candidate molecular targets for the action of DEET may aid in the design of safer and more effective insect repellents.

Recent developments in the chemistry of sandalwood odorants.

PubMed

Brocke, Constanze; Eh, Marcus; Finke, Anja

2008-06-01

Natural sandalwood oil, a unique and valuable ingredient in fine perfumery, has been the focus of scientific interest for many years. Due to its scarcity and its high price, the search for novel synthetic raw materials imitating the characteristic odor profile of sandalwood oil is as challenging as ever. In this context, the preparation of the novel sandalwood odorants 26, 33, and 39 will be discussed, including their sensory properties and structure-odor relationship.

Pattern Recognition Algorithm for High-Sensitivity Odorant Detection in Unknown Environments

NASA Technical Reports Server (NTRS)

Duong, Tuan A.

2012-01-01

In a realistic odorant detection application environment, the collected sensory data is a mix of unknown chemicals with unknown concentrations and noise. The identification of the odorants among these mixtures is a challenge in data recognition. In addition, deriving their individual concentrations in the mix is also a challenge. A deterministic analytical model was developed to accurately identify odorants and calculate their concentrations in a mixture with noisy data.

A computational study of odorant transport and deposition in the canine nasal cavity: implications for olfaction.

PubMed

Lawson, M J; Craven, B A; Paterson, E G; Settles, G S

2012-07-01

Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.

Characterization of the Major Odor-Active Compounds in the Leaves of the Curry Tree Bergera koenigii L. by Aroma Extract Dilution Analysis.

PubMed

Steinhaus, Martin

2015-04-29

Curry leaves are a popular seasoning herb with a pronounced sulfury and burnt odor, the molecular background of which was yet unclear. Application of an aroma extract dilution analysis to the volatile fraction of curry leaves isolated by solvent extraction and solvent-assisted flavor evaporation afforded 23 odor-active compounds with flavor dilution (FD) factors ranging from 1 to 8192. On the basis of the comparison of their retention indices, mass spectra, and odor properties with data of reference compounds, the structures of 22 odorants could be assigned, 15 of which had not been reported in curry leaves before. Odorants with high FD factors included 1-phenylethanethiol (FD factor 8192), linalool (4096), α-pinene (2048), 1,8-cineole (1024), (3Z)-hex-3-enal (256), 3-(methylsulfanyl)propanal (128), myrcene (64), (3Z)-hex-3-en-1-ol (32), and (2E,6Z)-nona-2,6-dienal (32). The unique sulfury and burnt odor exhibited by 1-phenylethanethiol in combination with its high FD factor suggested that it constitutes the character impact compound of fresh curry leaf aroma.

Sniffing shapes the dynamics of olfactory bulb gamma oscillations in awake behaving rats.

PubMed

Rosero, Mario A; Aylwin, María L

2011-09-01

Mammals actively sample the environment for relevant olfactory objects. This active sampling is revealed by rapid changes in respiratory rate that influence the olfactory input. Yet the role of sniffing in shaping the neural responses to odorants has not been elucidated. In the olfactory bulb (OB), odorant-evoked gamma oscillations reflect the synchronous activity of mitral/tufted cells, a proposed mechanism for odorant representation. Here we examined the effect of sniffing frequency on the odorant-evoked gamma oscillations in the OB. We simultaneously recorded the respiratory rate and the local field potential while rats performed a lick/no-lick olfactory discrimination task with low odorant concentrations. High-frequency sniffing (HFS) augmented the power of gamma oscillations, suggesting an increase in the sensitivity to odorants. By contrast, coupling of the gamma oscillations to the sniff cycle and the amplitude of individual bursts were not modified by the respiratory rate. However, HFS prolonged the overall response to odorants and increased the frequency of the gamma oscillations, indicating that HFS reduces the adaptation to continuous odorant stimulation. Therefore, the increase in gamma power during HFS is the result of more frequent gamma bursts and the extended response to odorants. As odorant discrimination can be performed in a single sniff, a reduction in the adaptation mediated by HFS of novel odorants may facilitate odorant memory formation for subsequent odorant identification. Finally, these results corroborate that olfactory sampling should be integrated to the study of odorant coding in behaving animals. © 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

A unique memory process modulated by emotion underpins successful odor recognition and episodic retrieval in humans

PubMed Central

Saive, Anne-Lise; Royet, Jean-Pierre; Ravel, Nadine; Thévenet, Marc; Garcia, Samuel; Plailly, Jane

2014-01-01

We behaviorally explore the link between olfaction, emotion and memory by testing the hypothesis that the emotion carried by odors facilitates the memory of specific unique events. To investigate this idea, we used a novel behavioral approach inspired by a paradigm developed by our team to study episodic memory in a controlled and as ecological as possible way in humans. The participants freely explored three unique and rich laboratory episodes; each episode consisted of three unfamiliar odors (What) positioned at three specific locations (Where) within a visual context (Which context). During the retrieval test, which occurred 24–72 h after the encoding, odors were used to trigger the retrieval of the complex episodes. The participants were proficient in recognizing the target odors among distractors and retrieving the visuospatial context in which they were encountered. The episodic nature of the task generated high and stable memory performances, which were accompanied by faster responses and slower and deeper breathing. Successful odor recognition and episodic memory were not related to differences in odor investigation at encoding. However, memory performances were influenced by the emotional content of the odors, regardless of odor valence, with both pleasant and unpleasant odors generating higher recognition and episodic retrieval than neutral odors. Finally, the present study also suggested that when the binding between the odors and the spatio-contextual features of the episode was successful, the odor recognition and the episodic retrieval collapsed into a unique memory process that began as soon as the participants smelled the odors. PMID:24936176

Odor Discrimination in Drosophila: From Neural Population Codes to Behavior

PubMed Central

Parnas, Moshe; Lin, Andrew C.; Huetteroth, Wolf; Miesenböck, Gero

2013-01-01

Summary Taking advantage of the well-characterized olfactory system of Drosophila, we derive a simple quantitative relationship between patterns of odorant receptor activation, the resulting internal representations of odors, and odor discrimination. Second-order excitatory and inhibitory projection neurons (ePNs and iPNs) convey olfactory information to the lateral horn, a brain region implicated in innate odor-driven behaviors. We show that the distance between ePN activity patterns is the main determinant of a fly’s spontaneous discrimination behavior. Manipulations that silence subsets of ePNs have graded behavioral consequences, and effect sizes are predicted by changes in ePN distances. ePN distances predict only innate, not learned, behavior because the latter engages the mushroom body, which enables differentiated responses to even very similar odors. Inhibition from iPNs, which scales with olfactory stimulus strength, enhances innate discrimination of closely related odors, by imposing a high-pass filter on transmitter release from ePN terminals that increases the distance between odor representations. PMID:24012006

[Remote sensing monitoring and screening for urban black and odorous water body: A review.

PubMed

Shen, Qian; Zhu, Li; Cao, Hong Ye

2017-10-01

Continuous improvement of urban water environment and overall control of black and odorous water body are not merely national strategic needs with the action plan for prevention and treatment of water pollution, but also the hot issues attracting the attention of people. Most previous researches concentrated on the study of cause, evaluation and treatment measures of this phenomenon, and there are few researches on the monitoring using remote sensing, which is often a strain to meet the national needs of operational monitoring. This paper mainly summarized the urgent research problems, mainly including the identification and classification standard, research on the key technologies, and the frame of remote sensing screening systems for the urban black and odorous water body. The main key technologies were concluded too, including the high spatial resolution image preprocessing and extraction technique for black and odorous water body, the extraction of water information in city zones, the classification of the black and odorous water, and the identification and classification technique based on satellite-sky-ground remote sensing. This paper summarized the research progress and put forward research ideas of monitoring and screening urban black and odorous water body via high spatial resolution remote sensing technology, which would be beneficial to having an overall grasp of spatial distribution and improvement progress of black and odorous water body, and provide strong technical support for controlling urban black and odorous water body.

Feasibility Study of Odor Biosensor Using Dissociate Neuronal Culture with Gene Expression of Ionotropic Odorant Receptors

NASA Astrophysics Data System (ADS)

Tanada, Norio; Sakurai, Takeshi; Mitsuno, Hidefumi; Bakkum, Douglas; Kanzaki, Ryohei; Takahashi, Hirokazu

We propose a highly sensitive and real-time odor biosensor by expressing ionotropic odorant receptors of insects into dissociated cultures of neurons of rats. The odorant-gated ion channel structure of insect odorant receptor is expected to allow easy functional expression into cells. The neuronal dissociated cultures of rats have two significant advantages: a long lifetime comparable to rats, i.e., a few years; and amplification ability from weak ionic currents of odorant receptors into easily detectable action potentials of neurons. In the present work, in order to show the feasibility of the proposed sensor, we attempt to express the pheromone receptors of silkmoth, Bombyx mori, into cultured neurons of rats. We demonstrate that 10% of neuronal cells transfected using Lipofectamine successfully expressed pheromone receptors, and that these cells showed significant increase of calcium signals by 50% at the presentation of pheromone.

Categorical dimensions of human odor descriptor space revealed by non-negative matrix factorization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chennubhotla, Chakra; Castro, Jason

2013-01-01

In contrast to most other sensory modalities, the basic perceptual dimensions of olfaction remain un- clear. Here, we use non-negative matrix factorization (NMF) - a dimensionality reduction technique - to uncover structure in a panel of odor profiles, with each odor defined as a point in multi-dimensional descriptor space. The properties of NMF are favorable for the analysis of such lexical and perceptual data, and lead to a high-dimensional account of odor space. We further provide evidence that odor di- mensions apply categorically. That is, odor space is not occupied homogenously, but rather in a discrete and intrinsically clustered manner.more » We discuss the potential implications of these results for the neural coding of odors, as well as for developing classifiers on larger datasets that may be useful for predicting perceptual qualities from chemical structures.« less

Differential associative training enhances olfactory acuity in Drosophila melanogaster.

PubMed

Barth, Jonas; Dipt, Shubham; Pech, Ulrike; Hermann, Moritz; Riemensperger, Thomas; Fiala, André

2014-01-29

Training can improve the ability to discriminate between similar, confusable stimuli, including odors. One possibility of enhancing behaviorally expressed discrimination (i.e., sensory acuity) relies on differential associative learning, during which animals are forced to detect the differences between similar stimuli. Drosophila represents a key model organism for analyzing neuronal mechanisms underlying both odor processing and olfactory learning. However, the ability of flies to enhance fine discrimination between similar odors through differential associative learning has not been analyzed in detail. We performed associative conditioning experiments using chemically similar odorants that we show to evoke overlapping neuronal activity in the fly's antennal lobes and highly correlated activity in mushroom body lobes. We compared the animals' performance in discriminating between these odors after subjecting them to one of two types of training: either absolute conditioning, in which only one odor is reinforced, or differential conditioning, in which one odor is reinforced and a second odor is explicitly not reinforced. First, we show that differential conditioning decreases behavioral generalization of similar odorants in a choice situation. Second, we demonstrate that this learned enhancement in olfactory acuity relies on both conditioned excitation and conditioned inhibition. Third, inhibitory local interneurons in the antennal lobes are shown to be required for behavioral fine discrimination between the two similar odors. Fourth, differential, but not absolute, training causes decorrelation of odor representations in the mushroom body. In conclusion, differential training with similar odors ultimately induces a behaviorally expressed contrast enhancement between the two similar stimuli that facilitates fine discrimination.

Odor composition analysis and odor indicator selection during sewage sludge composting

PubMed Central

Zhu, Yan-li; Zheng, Guo-di; Gao, Ding; Chen, Tong-bin; Wu, Fang-kun; Niu, Ming-jie; Zou, Ke-hua

2016-01-01

ABSTRACT On the basis of total temperature increase, normal dehydration, and maturity, the odor compositions of surface and internal piles in a well-run sewage sludge compost plant were analyzed using gas chromatography–mass spectrometry with a liquid nitrogen cooling system and a portable odor detector. Approximately 80 types of substances were detected, including 2 volatile inorganic compounds, 4 sulfur organic compounds, 16 benzenes, 27 alkanes, 15 alkenes, and 19 halogenated compounds. Most pollutants were mainly produced in the mesophilic and pre-thermophilic periods. The sulfur volatile organic compounds contributed significantly to odor and should be controlled primarily. Treatment strategies should be based on the properties of sulfur organic compounds. Hydrogen sulfide, methyl mercaptan, dimethyl disulfide, dimethyl sulfide, ammonia, and carbon disulfide were selected as core indicators. Ammonia, hydrogen sulfide, carbon disulfide, dimethyl disulfide, methyl mercaptan, dimethylbenzene, phenylpropane, and isopentane were designated as concentration indicators. Benzene, m-xylene, p-xylene, dimethylbenzene, dichloromethane, toluene, chlorobenzene, trichloromethane, carbon tetrachloride, and ethylbenzene were selected as health indicators. According to the principle of odor pollution indicator selection, dimethyl disulfide was selected as an odor pollution indicator of sewage sludge composting. Monitoring dimethyl disulfide provides a highly scientific method for modeling and evaluating odor pollution from sewage sludge composting facilities. Implications: Composting is one of the most important methods for sewage sludge treatment and improving the low organic matter content of many agricultural soils. However, odors are inevitably produced during the composting process. Understanding the production and emission patterns of odors is important for odor control and treatment. Core indicators, concentration indicators, and health indicators provide an index system to odor evaluation. An odor pollution indicator provides theoretical support for further modelling and evaluating odor pollution from sewage sludge composting facilities. PMID:27192607

Regulation of sexual odor preference by sex steroids in the posterodorsal medial amygdala in female rats.

PubMed

Fujiwara, Masaya; Nitta, Asano; Chiba, Atsuhiko

2016-06-01

Our previous study in male rats demonstrated that bilateral administration of flutamide, an androgen receptor (AR) antagonist, into the posterodorsal medial amygdala (MePD) increased the time sniffing male odors to as high as that sniffing estrous odors, eliminating the preference for estrous odors over male odors. This made us speculate that under blockade of AR in the MePD, testosterone-derived estrogen acting on the same brain region arouses interest in male odors which is otherwise suppressed by concomitant action of androgen. In cyclic female rats, endogenous androgen has been thought to be involved in inhibitory regulation of estrogen-activated sexual behavior. Thus, in the present study, we investigated the possibility that in female rats the arousal of interest in male odors is also normally regulated by both estrogen and androgen acting on the MePD, as predicted by our previous study in male rats. Implantation of either the estrogen receptor blocker tamoxifen (TX) or a non-aromatizable androgen 5α-dihydrotestosterone (DHT) into the MePD of ovariectomized, estrogen-primed female rats eliminated preference for male odors over estrous odors by significantly decreasing the time sniffing male odors to as low as that sniffing estrous odors. The subsequent odor discrimination tests confirmed that the DHT and TX administration did not impair the ability to discriminate between male and estrous odors. These results suggest that in estrous female rats estrogen action in the MePD plays critical roles in the expression of the preference for male odors while androgen action in the same brain region interferes with the estrogen action. Copyright © 2016 Elsevier Inc. All rights reserved.

A CO2-Free Synthetic Host-Odor Mixture That Attracts and Captures Triatomines: Effect of Emitted Odorant Ratios.

PubMed

Guidobaldi, F; Guerenstein, P G

2016-07-01

Triatomines, vectors of Chagas Disease, are hematophagous insects. Efforts have been made to develop synthetic attractants based on vertebrate odor-to lure them into traps. However, because those lures are not practical or have low capture efficiency, they are not in use in control programs. Therefore, more work is needed to reach a practical and efficient odor lure. Recently, a three-component, CO 2 -free, synthetic blend of vertebrate odor (consisting of ammonia, l-(+)-lactic acid, and hexanoic acid), known as Sweetscent (Biogents AG, Regensburg, Germany), was shown to attract and capture triatomines in the laboratory. In this study, using a trap olfactometer and an odor blend with constituents similar to those of Sweetscent (delivered from low-density polyethylene sachets) we found that the odorant ratios of the mixtures have a strong effect in the capture of triatomines. The blend with the most efficient combination of odorant ratios evoked ca. 81% capture in two relevant triatomine species. In the case of the most effective odor mixtures, we measured the odor mass emission for the three components of the mixture and therefore were able to estimate the odorant ratios emitted that were responsible for such a high capture performance. Thus, in those mixtures, pentanoic acid was the main component (ca. 65 %) followed by ammonia (ca. 28%) and, l(+)-lactic acid (ca. 7 %). Our results are encouraging as efficient, practical, and cheap odor baits to trap triatomines in the field would be within reach. The odor-delivery system used should be improved to increase stability of odor emission. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Odor composition analysis and odor indicator selection during sewage sludge composting.

PubMed

Zhu, Yan-Li; Zheng, Guo-di; Gao, Ding; Chen, Tong-Bin; Wu, Fang-Kun; Niu, Ming-Jie; Zou, Ke-Hua

2016-09-01

On the basis of total temperature increase, normal dehydration, and maturity, the odor compositions of surface and internal piles in a well-run sewage sludge compost plant were analyzed using gas chromatography-mass spectrometry with a liquid nitrogen cooling system and a portable odor detector. Approximately 80 types of substances were detected, including 2 volatile inorganic compounds, 4 sulfur organic compounds, 16 benzenes, 27 alkanes, 15 alkenes, and 19 halogenated compounds. Most pollutants were mainly produced in the mesophilic and pre-thermophilic periods. The sulfur volatile organic compounds contributed significantly to odor and should be controlled primarily. Treatment strategies should be based on the properties of sulfur organic compounds. Hydrogen sulfide, methyl mercaptan, dimethyl disulfide, dimethyl sulfide, ammonia, and carbon disulfide were selected as core indicators. Ammonia, hydrogen sulfide, carbon disulfide, dimethyl disulfide, methyl mercaptan, dimethylbenzene, phenylpropane, and isopentane were designated as concentration indicators. Benzene, m-xylene, p-xylene, dimethylbenzene, dichloromethane, toluene, chlorobenzene, trichloromethane, carbon tetrachloride, and ethylbenzene were selected as health indicators. According to the principle of odor pollution indicator selection, dimethyl disulfide was selected as an odor pollution indicator of sewage sludge composting. Monitoring dimethyl disulfide provides a highly scientific method for modeling and evaluating odor pollution from sewage sludge composting facilities. Composting is one of the most important methods for sewage sludge treatment and improving the low organic matter content of many agricultural soils. However, odors are inevitably produced during the composting process. Understanding the production and emission patterns of odors is important for odor control and treatment. Core indicators, concentration indicators, and health indicators provide an index system to odor evaluation. An odor pollution indicator provides theoretical support for further modelling and evaluating odor pollution from sewage sludge composting facilities.

EEG responses to low-level chemicals in normals and cacosmics.

PubMed

Schwartz, G E; Bell, I R; Dikman, Z V; Fernandez, M; Kline, J P; Peterson, J M; Wright, K P

1994-01-01

Recent studies from the University of Arizona indicate that normal subjects, both college students and the elderly, can register the presence of low-intensity odors in the electroencephalogram (EEG) in the absence of conscious awareness of the odors. The experimental paradigm involves subjects sniffing pairs of bottles, one containing an odorant (e.g. isoamyl acetate) dissolved in an odorless solvent (water or liquid silicone), the other containing just the solvent, while 19 channels of EEG are continuously recorded. For the low-intensity odor conditions, concentrations are adjusted downward (decreased) until subjects correctly identify the odor bottle at chance (50%). The order of odorants, concentrations, and hand holding the control bottle, are counterbalanced within and across subjects. Three previous experiments found that alpha activity (8-12 hz) decreased in midline and posterior regions when subjects sniffed the low-intensity odors. The most recent study suggests that decreased theta activity (4-8 hz) may reflect sensory registration and decreased alpha activity may reflect perceptual registration. In a just completed experiment involving college students who were selected based on combinations of high and low scores on a scale measuring cacosmia (chemical odor intolerance) and high and low scores on a scale measuring depression, cacosmic subjects (independent of depression) showed greater decreases in low-frequency alpha (8-10 hz) and greater increases in low-frequency beta (12-16 hz) to the solvent propylene glycol compared to an empty bottle. Topographic EEG mapping to low-intensity odorants may provide a useful tool for investigating possible increased sensitivity to specific chemicals in chemically sensitive individuals.

Animal-to-Animal Variation in Odor Preference and Neural Representation of Odors

NASA Astrophysics Data System (ADS)

Honegger, Kyle; Smith, Matthew; Turner, Glenn; de Bivort, Benjamin

Across any population of animals, individuals exhibit diverse behaviors and reactions to sensory stimuli like tastes and odors. While idiosyncratic behavior is ubiquitous, its biological basis is poorly understood. In this talk, I will present evidence that individual fruit flies (Drosophila melanogaster) display idiosyncratic olfactory behaviors and discuss our ongoing efforts to map these behavioral differences to variation in neural circuits. Using a high-throughput, single-fly assay for odor preference, we have demonstrated that highly inbred flies display substantial animal-to-animal variability, beyond that expected from experimental error, and that these preferences persist over days. Using in vivo two-photon calcium imaging, we are beginning to examine the idiosyncrasy of neural coding in the fly olfactory pathway and find that the odor responses of individual processing channels in the antennal lobe can vary substantially from fly to fly. These results imply that individual differences in neural coding may be used to predict the idiosyncratic behavior of an individual - a hypothesis we are currently testing by imaging neural activity from flies after measuring their odor preferences.

Association among bad breath, body mass index, and alcohol intake.

PubMed

Rosenberg, M; Knaan, T; Cohen, D

2007-10-01

Bad breath is a common condition, difficult to assess in the general population. In the present study, we tested the hypothesis that a self-administered questionnaire can help identify factors associated with greater risk of oral malodor. Persons (n = 88) undergoing routine medical check-ups completed a questionnaire including 38 questions on general and oral health, dietary habits, and their own oral malodor levels. Oral malodor assessments included odor judge scores, volatile sulfide levels (via a Halimeter, Interscan Corp.), and salivary beta-galactosidase. Among the questionnaire results, 9 responses were significantly associated with odor judge scores (p < 0.05, unpaired t test), including questions on alcohol intake and body mass index (BMI). Predictions of odor judge scores based on these 9 questions (linear multiple regression analysis) yielded R = 0.601; when introduced together with Halimeter and beta-galactosidase scores, the correlation rose to R = 0.843. The results suggest that alcohol intake and BMI may be factors that help predict oral malodor.

Characterization of outdoor air particles as source of impurities in supply air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasanen, P.; Kalliokoski, P.; Tuomainen, A.

1997-12-31

Odor emission of supply air filters has proved to be a major source of stuffy odor of supply air. In this study, the odor emission characteristics of outdoor air particles and odor emissions of coarse prefilters and fine filters were studied. The outdoor air samples were collected by the aid of high volume impactor. Odor emissions of the size fractions, < 2.1 {micro}m , 2.1--10 {micro}m and >10 {micro}m were studied separately in laboratory with a trained olf panel: The odor emissions of the ventilation filters in real use were evaluated five times during the 14 month study period. Aftermore » the field evaluation the emissions of carbonyl compounds and other volatile organic compounds. The odor emissions of outdoor air particles were the highest during the heating season and lowest in the summer. The particles in the coarsest fraction had the most abundant emissions (1,200 olf/g) while the emissions from fine particles were lowest (100 olf/g). The odor emissions evaluated from the coarse and fine ventilation filters supported the finding that particles collected on coarse prefilter had the most abundant odor emission.« less

The Impact of Stress on Odor Perception.

PubMed

Hoenen, Matthias; Wolf, Oliver T; Pause, Bettina M

2017-01-01

The olfactory system and emotional systems are highly intervened and share common neuronal structures. The current study investigates whether emotional (e.g., anger and fear) and physiological (saliva cortisol) stress responses are associated with odor identification ability and hedonic odor judgments (intensity, pleasantness, and unpleasantness). Nineteen men participated in the modified Trier Social Stress Test (TSST) and a control session (cycling on a stationary bike). The physiological arousal was similar in both sessions. In each session, participants' odor identification score was assessed using the University of Pennsylvania Smell Identification Test, and their transient mood was recorded on the dimensions of valence, arousal, anger, and anxiety. Multivariate regression analyses show that an increase of cortisol in the TSST session (as compared with the control session) is associated with better odor identification performance (β = .491) and higher odor intensity ratings (β = .562). However, increased anger in the TSST session (as compared with the control session) is associated with lower odor identification performance (β = -.482). The study shows divergent effects of the emotional and the physiological stress responses, indicating that an increase of cortisol is associated with better odor identification performance, whereas increased anger is associated with poorer odor identification performance.

[Actinobacteria and their odor-producing capacities in a surface water in Shanghai].

PubMed

Chen, Jiao; Bai, Xiao-hui; Lu, Ning; Wang, Xian-yun; Zhang, Yong-hui; Wu, Pan-cheng; Guo, Xin-chi

2014-10-01

The odor in raw water is one of the main sources of odor in drinking water. The occurrence of actinobacteria and their odor producing capacities in a reservoir in.Shanghai were investigated. Gauze's medium and membrane filtration were used for actinobacteria isolation. Through combined methods of 16S rRNA sequencing, colony and hyphae morphology, carbon source utilization, physiological and biochemical characteristics, 40 strains of actinobacteria were identified from the reservoir. Results showed that there were 38 Streptomyces, an Aeromicrobium and a Pseudonocardia. Liquid culture medium and the real reservoir water were used to test the odor producing capacity of these 40 strains of actinobacteria, and headspace solid phase microextraction (HS-SPME) and high resolution gas chromatography mass spectroscopy (GC/MS) were used to analyze the odor compounds 2-methylisoborneol (2-MIB) and geosmin (GSM) in the fermentation liquor. The test results showed that, the odor-producing capacities of these actinobacteria in different fermentation media showed different variation trends, even within the genera Streptomyces. The odor-producing capacity of actinobacteria in the liquid culture medium could not represent their states in the reservoir water or their actual odor contribution to the aquatic environment.

Nanocellulose-Zeolite Composite Films for Odor Elimination.

PubMed

Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

2015-07-08

Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 μm thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

Odor discrimination in Drosophila: from neural population codes to behavior.

PubMed

Parnas, Moshe; Lin, Andrew C; Huetteroth, Wolf; Miesenböck, Gero

2013-09-04

Taking advantage of the well-characterized olfactory system of Drosophila, we derive a simple quantitative relationship between patterns of odorant receptor activation, the resulting internal representations of odors, and odor discrimination. Second-order excitatory and inhibitory projection neurons (ePNs and iPNs) convey olfactory information to the lateral horn, a brain region implicated in innate odor-driven behaviors. We show that the distance between ePN activity patterns is the main determinant of a fly's spontaneous discrimination behavior. Manipulations that silence subsets of ePNs have graded behavioral consequences, and effect sizes are predicted by changes in ePN distances. ePN distances predict only innate, not learned, behavior because the latter engages the mushroom body, which enables differentiated responses to even very similar odors. Inhibition from iPNs, which scales with olfactory stimulus strength, enhances innate discrimination of closely related odors, by imposing a high-pass filter on transmitter release from ePN terminals that increases the distance between odor representations. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

A broad diversity of volatile carboxylic acids, released by a bacterial aminoacylase from axilla secretions, as candidate molecules for the determination of human-body odor type.

PubMed

Natsch, Andreas; Derrer, Samuel; Flachsmann, Felix; Schmid, Joachim

2006-01-01

Human body odor is to a large part determined by secretions of glands in the axillary regions. Two key odoriferous principles, 3-methylhex-2-enoic acid (3MH2; 4/5) and 3-hydroxy-3-methylhexanoic acid (HMHA; 6) have been shown to be released from glutamine conjugates secreted in the axilla by a specific N(alpha)-acyl-glutamine aminoacylase (N-AGA) obtained from axilla isolates of Corynebacteria sp. However, the low number of different odorants reported in humans stands in contrast to the observed high inter-individual variability in body odors. Axilla secretions of individual donors were, therefore, analyzed in detail. The secretions were treated with N-AGA, analyzed by GC/MS, and compared to undigested controls. Over 28 different carboxylic acids were released by this enzyme from odorless axilla secretions (Table 1). Many of these body odorants have not been reported before from a natural source, and they include several aliphatic 3-hydroxy acids with 4-Me branches, 3,4-unsaturated, 4-Et-branched aliphatic acids, and a variety of degradation products of amino acids. The odor threshold of some of the acids was found to be in the range of 1 ng. Most of these compounds were present in all donors tested, but in highly variable relative amounts, and they are, thus, candidate molecules as key components of a 'compound odor' determining the individual types of human body odor.

Activation of Neural Pathways Associated with Sexual Arousal in Non-Human Primates

PubMed Central

Ferris, Craig F.; Snowdon, Charles T.; King, Jean A.; Sullivan, John M.; Ziegler, Toni E.; Olson, David P.; Schultz-Darken, Nancy J.; Tannenbaum, Pamela L.; Ludwig, Reinhold; Wu, Ziji; Einspanier, Almuth; Vaughan, J. Thomas; Duong, Timothy Q.

2006-01-01

Purpose To evaluate brain activity associated with sexual arousal, fully conscious male marmoset monkeys were imaged during presentation of odors that naturally elicit high levels of sexual activity and sexual motivation. Material and Methods Male monkeys were lightly anesthetized, secured in a head and body restrainer with a built-in birdcage resonator and positioned in a 9.4-Tesla spectrometer. When fully conscious, monkeys were presented with the odors of a novel receptive female or an ovariectomized monkey. Both odors were presented during an imaging trial and the presentation of odors was counterbalanced. Significant changes in both positive and negative BOLD signal were mapped and averaged. Results Periovulatory odors significantly increased positive BOLD signal in several cortical areas: the striatum, hippocampus, septum, periaqueductal gray, and cerebellum, in comparison with odors from ovariectomized monkeys. Conversely, negative BOLD signal was significantly increased in the temporal cortex, cingulate cortex, putamen, hippocampus, substantia nigra, medial preoptic area, and cerebellum with presentation of odors from ovariectomized marmosets as compared to periovulatory odors. A common neural circuit comprising the temporal and cingulate cortices, putamen, hippocampus, medial preoptic area, and cerebellum shared both the positive BOLD response to periovulatory odors and the negative BOLD response to odors of ovariectomized females. Conclusion These data suggest the odor-driven enhancement and suppression of sexual arousal affect neuronal activity in many of the same general brain areas. These areas included not only those associated with sexual activity, but also areas involved in emotional processing and reward. PMID:14745749

Utilization of Bagasse Fly Ash to Remove the Unpleasant Odor of Stevia Extract and Soy Milk

NASA Astrophysics Data System (ADS)

Ashadi; Masykuri, M.; Haryono

2017-04-01

Stevia is a safe natural sweetener that, but has a slightly unpleasant odor. Soy milk is undoubtedly high nutritional value, soy milk slightly unpleasant odor. Bagasse Fly Ash (BFA) is a sugar factory waste which is abundant, not widely used yet, and allowed to accumulate around the sugar factory. BFA can be activated with a solution of NaOH become adsorbent. Utilization of activated BFA to remove the odor of stevia extract and soy milk means the utilization of a waste to reduce other waste. Deodorizing done by batch system. Before being used as adsorbent, BFA characterized using SEM, XRD, FTIR, and AAS. Odor and color analysis conducted by organoleptic. The results shown activation increases the cavity, BFA containing SiO2 and Al2O3, does not contain Pb, Cr, Cd. The results shown that the BFA can reduce odor of stevia from a scale of 4 to 2, the color becomes more clear, unpleasant odor of soy milk is also reduced.

Wild Western Lowland Gorillas Signal Selectively Using Odor

PubMed Central

Klailova, Michelle; Lee, Phyllis C.

2014-01-01

Mammals communicate socially through visual, auditory and chemical signals. The chemical sense is the oldest sense and is shared by all organisms including bacteria. Despite mounting evidence for social chemo-signaling in humans, the extent to which it modulates behavior is debated and can benefit from comparative models of closely related hominoids. The use of odor cues in wild ape social communication has been only rarely explored. Apart from one study on wild chimpanzee sniffing, our understanding is limited to anecdotes. We present the first study of wild gorilla chemo-communication and the first analysis of olfactory signaling in relation to arousal levels and odor strength in wild apes. If gorilla scent is used as a signaling mechanism instead of only a sign of arousal or stress, odor emission should be context specific and capable of variation as a function of the relationships between the emitter and perceiver(s). Measured through a human pungency scale, we determined the factors that predicted extreme levels of silverback odor for one wild western lowland gorilla (Gorilla gorilla gorilla) group silverback. Extreme silverback odor was predicted by the presence and intensity of inter-unit interactions, silverback anger, distress and long-calling auditory rates, and the absence of close proximity between the silverback and mother of the youngest infant. Odor strength also varied according to the focal silverback's strategic responses during high intensity inter-unit interactions. Silverbacks appear to use odor as a modifiable form of communication; where odor acts as a highly flexible, context dependent signaling mechanism to group members and extra-group units. The importance of olfaction to ape social communication may be especially pertinent in Central African forests where limited visibility may necessitate increased reliance on other senses. PMID:25006973

Effect of Subcritical Fluid Extraction on the High Quality of Headspace Oil from Jasminum sambac (L.) Aiton.

PubMed

Ye, Qiuping; Jin, Xinyi; Wei, Shiqin; Zheng, Gongyu; Li, Xinlei

2016-05-01

Subcritical fluid extraction (SFE), as a novel method, was applied to investigate the yield, quality, and sensory evaluation of headspace oil from Jasminum sambac (L.) Aiton in comparison with petroleum ether extraction (PEE). The results indicated that the yield of the headspace oil using SFE was significantly higher (P < 0.05) than when using PEE. SFE contributed to obtaining alcohols and ethers, prevented the thermal reaction of terpenes, and reduced α-caryophyllene and β-caryophyllene in the headspace oil. The contents of linalool (21.90%) and benzyl acetate (16.31%) were higher via SFE than PEE. In addition, the sensory evaluation of SFE was superior to PEE, indicating a fresh, jasmine-like odor and green-yellow color. Thus, SFE is an improved method for obtaining natural headspace oil from jasmine flowers.

Identification of potent odorants in different cultivars of snake fruit [Salacca zalacca (Gaert.) Voss] using gas chromatography-olfactometry.

PubMed

Wijaya, C H; Ulrich, D; Lestari, R; Schippel, K; Ebert, G

2005-03-09

Three cultivars of snake fruits, Pondoh Hitam, Pondoh Super, and Gading, were freshly extracted using liquid-liquid extraction. The aroma compounds of the three samples were analyzed by GC-MS and GC-olfactometry using the nasal impact frequency (NIF) method. A total of 24 odor-active compounds were associated with the aroma of snake fruit. Methyl 3-methylpentanoate was regarded as the character impact odorant of typical snake fruit aroma. 2-Methylbutanoic acid, 3-methylpentanoic acid, and an unknown odorant with very high intensity were found to be responsible for the snake fruit's sweaty odor. Other odorants including methyl 3-methyl-2-butenoate (overripe fruity, ethereal), methyl 3-methyl-2-pentenoate (ethereal, strong green, woody), and 2,5-dimethyl-4-hydroxy-3[2]-furanone (caramel, sweet, cotton candy-like) contribute to the overall aroma of snake fruit. Methyl dihydrojasmonate and isoeugenol, which also have odor impact, were identified for the first time as snake fruit volatiles. The main differences between the aroma of Pondoh and Gading cultivars could be attributed to the olfactory attributes (metallic, chemical, rubbery, strong green, and woody), which were perceived by most of the panelists in the Pondoh samples but were not detected in the Gading samples. This work is a prerequisite for effective selection of salak genotypes with optimal aroma profiles for high consumer acceptance.

Characterization of the Potent Odorants Contributing to the Characteristic Aroma of Matcha by Gas Chromatography-Olfactometry Techniques.

PubMed

Baba, Ryoko; Amano, Yohei; Wada, Yoshiyuki; Kumazawa, Kenji

2017-03-31

The odorants contributing to the characteristic aroma of matcha were investigated by analysis of the headspace samples and the volatile fractions prepared by a combination of solvent extraction and the SAFE techniques using three matcha powders of different grades (high, medium, and low). Gas chromatography-olfactometry of the headspace samples (GCO-H) and aroma extract dilution analysis (AEDA) applied to the volatile fractions revealed 16 (FD factor ≥1) and 39 (FD factor ≥4 3 ) odor-active peaks, respectively. Among them, 14 and 37 of the odorants, most of which were newly detected in matcha, were identified or tentatively identified by GC-MS and GC-O, respectively. By comparing the perceived odorants of three matcha powders, it was revealed that eight compounds with sweet, green, metallic, and floral notes showed high flavor dilution (FD) factors irrespective of the grades. In addition, some odorants were suggested to influence the characteristic aroma of each grade. Furthermore, trans-4,5-epoxy-(E)-2-decenal, one of the potent odorants of matcha, was revealed to exist as a racemic mixture in matcha. This result suggested that trans-4,5-epoxy-(E)-2-decenal is formed by a nonenzymatic reaction in matcha, different from that in black tea, and that the unique manufacturing process of matcha has a close connection with its formation.

The Hydrodynamics and Odorant Transport Phenomena of Olfaction in the Hammerhead Shark

NASA Astrophysics Data System (ADS)

Rygg, Alex; Craven, Brent

2013-11-01

The hammerhead shark possesses a unique head morphology that is thought to facilitate enhanced olfactory performance. The olfactory organs, located at the distal ends of the cephalofoil, contain numerous lamellae that increase the surface area for olfaction. Functionally, for the shark to detect chemical stimuli, water-borne odors must reach the olfactory sensory epithelium that lines these lamellae. Thus, odorant transport from the aquatic environment to the sensory epithelium is the first critical step in olfaction. Here we investigate the hydrodynamics and odorant transport phenomena of olfaction in the hammerhead shark based on an anatomically-accurate reconstruction of the head and olfactory chamber from high-resolution micro-CT and MRI scans of a cadaver specimen. Computational fluid dynamics (CFD) simulations of water flow in the reconstructed model reveal the external and internal hydrodynamics of olfaction during swimming. Odorant transport in the olfactory organ is investigated using a multi-scale approach, whereby molecular dynamics (MD) simulations are used to calculate odorant partition coefficients that are subsequently utilized in macro-scale CFD simulations of odorant deposition. The hydrodynamic and odorant transport results are used to elucidate several important features of olfactory function in the hammerhead shark.

Programming of stress-related behavior and epigenetic neural gene regulation in mice offspring through maternal exposure to predator odor

PubMed Central

St-Cyr, Sophie; McGowan, Patrick O.

2015-01-01

Perinatal stress mediated through the mother can lead to long-term alterations in stress-related phenotypes in offspring. The capacity for adaptation to adversity in early life depends in part on the life history of the animal. This study was designed to examine the behavioral and neural response in adult offspring to prenatal exposure to predator odor: an ethologically-relevant psychological stressor. Pregnant mice were exposed daily to predator odors or distilled water control over the second half of the pregnancy. Predator odor exposure lead to a transient decrease in maternal care in the mothers. As adults, the offspring of predator odor-exposed mothers showed increased anti-predator behavior, a predator-odor induced decrease in activity and, in female offspring, an increased corticosterone (CORT) response to predator odor exposure. We found a highly specific response among stress-related genes within limbic brain regions. Transcript abundance of Corticotropin-releasing hormone receptor 1 (CRHR1) was elevated in the amygdala in adult female offspring of predator odor-exposed mothers. In the hippocampus of adult female offspring, decreased Brain-derived neurotrophic factor (BDNF) transcript abundance was correlated with a site-specific decrease in DNA methylation in Bdnf exon IV, indicating the potential contribution of this epigenetic mechanism to maternal programming by maternal predator odor exposure. These data indicate that maternal predator odor exposure alone is sufficient to induce an altered stress-related phenotype in adulthood, with implications for anti-predator behavior in offspring. PMID:26082698

Programming of stress-related behavior and epigenetic neural gene regulation in mice offspring through maternal exposure to predator odor.

PubMed

St-Cyr, Sophie; McGowan, Patrick O

2015-01-01

Perinatal stress mediated through the mother can lead to long-term alterations in stress-related phenotypes in offspring. The capacity for adaptation to adversity in early life depends in part on the life history of the animal. This study was designed to examine the behavioral and neural response in adult offspring to prenatal exposure to predator odor: an ethologically-relevant psychological stressor. Pregnant mice were exposed daily to predator odors or distilled water control over the second half of the pregnancy. Predator odor exposure lead to a transient decrease in maternal care in the mothers. As adults, the offspring of predator odor-exposed mothers showed increased anti-predator behavior, a predator-odor induced decrease in activity and, in female offspring, an increased corticosterone (CORT) response to predator odor exposure. We found a highly specific response among stress-related genes within limbic brain regions. Transcript abundance of Corticotropin-releasing hormone receptor 1 (CRHR1) was elevated in the amygdala in adult female offspring of predator odor-exposed mothers. In the hippocampus of adult female offspring, decreased Brain-derived neurotrophic factor (BDNF) transcript abundance was correlated with a site-specific decrease in DNA methylation in Bdnf exon IV, indicating the potential contribution of this epigenetic mechanism to maternal programming by maternal predator odor exposure. These data indicate that maternal predator odor exposure alone is sufficient to induce an altered stress-related phenotype in adulthood, with implications for anti-predator behavior in offspring.

Internal Representation and Memory Formation of Odor Preference Based on Oscillatory Activities in a Terrestrial Slug

ERIC Educational Resources Information Center

Sekiguchi, Tatsuhiko; Furudate, Hiroyuki; Kimura, Tetsuya

2010-01-01

The terrestrial slug "Limax" exhibits a highly developed ability to learn odors with a small nervous system. When a fluorescent dye, Lucifer Yellow (LY), is injected into the slug's body cavity after odor-taste associative conditioning, a group of neurons in the procerebral (PC) lobe, an olfactory center of the slug, is labeled by LY. We examined…

The Procerebrum Is Necessary for Odor-Aversion Learning in the Terrestrial Slug "Limax Valentianus"

ERIC Educational Resources Information Center

Kasai, Yoko; Watanabe, Satoshi; Kirino, Yutaka; Matsuo, Ryota

2006-01-01

The terrestrial slug "Limax" has a highly developed ability to associate the odor of some foods (e.g., carrot juice) with aversive stimuli such as the bitter taste of quinidine solution. The procerebrum (PC) is a part of the slug's brain thought to be involved in odor-aversion learning, but direct evidence is still lacking. Here, the authors…

Extended local similarity analysis (eLSA) reveals unique associations between bacterial community structure and odor emission during pig carcasses decomposition.

PubMed

Ki, Bo-Min; Ryu, Hee Wook; Cho, Kyung-Suk

2018-02-22

Soil burial and composting methods have been widely used for the disposal of pig carcasses. The relationship between bacterial community structure and odor emission was examined using extended local similarity analysis (eLSA) during the degradation of pig carcasses in soil and compost. In soil, Hyphomicrobium, Niastella, Rhodanobacter, Polaromonas, Dokdonella and Mesorhizobium were associated with the emission of sulfur-containing odors such as hydrogen sulfide, methyl mercaptan and dimethyl disulfide. Sphingomonas, Rhodanobacter, Mesorhizobium, Dokdonella, Leucobacter and Truepera were associated with the emission of nitrogen-containing odors including ammonia and trimetylamine. In compost, however, Carnobacteriaceae, Lachnospiaceae and Clostridiales were highly correlated with the emission of sulfur-containing odors, while Rumincoccaceae was associated with the emission of nitrogen-containing odors. The emission of organic acids was closely related to Massilia, Sphaerobacter and Bradyrhizobiaceae in soil, but to Actinobacteria, Sporacetigenium, Micromonosporaceae and Solirubrobacteriales in compost. This study suggests that network analysis using eLSA is a useful strategy for exploring the mechanisms of odor emission during biodegradation of pig carcasses.

Character impact odorants of fennel fruits and fennel tea.

PubMed

Zeller, Annette; Rychlik, Michael

2006-05-17

The flavor of fennel fruits and fennel tea was examined by aroma extract dilution analysis of the respective dichloromethane extracts. In both fennel fruits and tea, trans-anethole, anisaldehyde, and trans-4,5-epoxy-2(E)-decenal showed high flavor dilution (FD) factors followed by fenchone, 1,8-cineole, (R)-alpha-pinene, estragole, and beta-myrcene. On the basis of these results, the odorants showing higher FD factors were quantified in tea as well as in fruits, and odor activity values (OAV) in tea were calculated by dividing the concentration of the compound by its recognition threshold in water. The highest OAV was found for trans-anethole, followed by estragole, fenchone, 1,8-cineole, (R)-alpha-pinene, beta-myrcene, and anisaldehyde. From a comparison of the concentrations of odorants in fruits and tea, trans-anethole and estragole showed similar extraction rates of approximately 10-15%, whereas the extraction rates for (R)-alpha-pinene, beta-myrcene, and limonene were below 2%. In contrast to this, fenchone, camphor, linalool, and carvone showed higher extraction rates (26-50%), whereas the high apparent extraction rates of anisalcohol (393%) and vanilline (480%) were attributed to the formation from precursors. Sensory studies of aqueous models containing odorants in the amounts quantified in fennel teas revealed high similarity of the models with the tea and proved that all impact odorants had been identified in their correct concentrations. Further sensory experiments showed that estragole had no odor impact on the overall flavor of fennel tea, and, therefore, a reduction of estragole in fennel products would have no negative impact on their sensoric quality. In contrast to this, trans-anethole and fenchone were found to be character impact compounds of fennel.

Computational Approaches for Decoding Select Odorant-Olfactory Receptor Interactions Using Mini-Virtual Screening

PubMed Central

Harini, K.; Sowdhamini, Ramanathan

2015-01-01

Olfactory receptors (ORs) belong to the class A G-Protein Coupled Receptor superfamily of proteins. Unlike G-Protein Coupled Receptors, ORs exhibit a combinatorial response to odors/ligands. ORs display an affinity towards a range of odor molecules rather than binding to a specific set of ligands and conversely a single odorant molecule may bind to a number of olfactory receptors with varying affinities. The diversity in odor recognition is linked to the highly variable transmembrane domains of these receptors. The purpose of this study is to decode the odor-olfactory receptor interactions using in silico docking studies. In this study, a ligand (odor molecules) dataset of 125 molecules was used to carry out in silico docking using the GLIDE docking tool (SCHRODINGER Inc Pvt LTD). Previous studies, with smaller datasets of ligands, have shown that orthologous olfactory receptors respond to similarly-tuned ligands, but are dramatically different in their efficacy and potency. Ligand docking results were applied on homologous pairs (with varying sequence identity) of ORs from human and mouse genomes and ligand binding residues and the ligand profile differed among such related olfactory receptor sequences. This study revealed that homologous sequences with high sequence identity need not bind to the same/ similar ligand with a given affinity. A ligand profile has been obtained for each of the 20 receptors in this analysis which will be useful for expression and mutation studies on these receptors. PMID:26221959

Sensory-specific appetite is affected by actively smelled food odors and remains stable over time in normal-weight women.

PubMed

Ramaekers, Mariëlle G; Boesveldt, Sanne; Gort, Gerrit; Lakemond, Catriona M M; van Boekel, Martinus A J S; Luning, Pieternel A

2014-08-01

Understanding overconsumption starts with knowledge of how separate factors influence our eating behavior. Food cues such as food odors are known for their effect on general appetite and sensory-specific appetite (SSA). Active sniffing rather than passive exposure may induce satiation over time. The objective of this study was to investigate how actively sniffing banana odors affects general appetite, SSA, and subsequent food intake. In a crossover study, 61 women actively smelled cups containing natural banana, artificial banana odor, or water (no odor) for 10 min. Treatment order was randomly assigned as much as possible. General appetite and SSA were monitored by using 100-mm visual analog scales during the 10 min of active sniffing, followed by ad libitum intake of banana milkshake. Results showed that SSA was consistently high (+12 mm) during actively sniffing natural or artificial banana odors, with no decrease in SSA over time. Sniffing both banana odors increased the appetite for banana (+11 mm) and other sweet products (+4 mm), whereas the appetite for savory products decreased by 7 mm (all P < 0.01) compared with no odor. Actively sniffing banana odor did not significantly influence food intake (P = 0.68) or general appetite scores (P = 0.06). In conclusion, SSA scores during active sniffing were identical to the SSA found in a similar study that used passive smelling, suggesting that SSA is independent of the manner of sniffing and exposure time. Moreover, sweet/savory categorization may suggest that food odors communicate information about the nutrient composition of their associated foods. These data clearly show the appetizing effects of food odors. © 2014 American Society for Nutrition.

Macroglomeruli for fruit odors change blend preference in Drosophila

NASA Astrophysics Data System (ADS)

Ibba, Irene; Angioy, Anna Maria; Hansson, Bill S.; Dekker, Teun

2010-12-01

The olfactory circuitry of Drosophila melanogaster is becoming increasingly clear. However, how olfactory processing translates into appropriate behavioral responses is still poorly understood. Using a sibling species approach, we tested how a perturbation in the olfactory circuitry affects odor preference. In a previous study, we found that the sibling species of D. melanogaster, the specialist D. sechellia, overrepresents a sensillum, ab3, the A neuron of which is sensitive to hexanoate esters, characteristic of the species' sole host, the Morinda citrifolia fruit. Concordantly, the corresponding glomerulus, DM2, is enlarged. In this study, we found that the ab3B neuron, the expansion of which was previously assumed to be pleiotropic and of no ecological significance, is in fact tuned to another morinda fruit volatile, 2-heptanone (HP). Axons of this neuron type arborize in a second enlarged glomerulus. In behavioral experiments we tested how this has affected the fly's odor preference. We demonstrate that D. sechellia has a reversed preference for the key ligands of these macroglomeruli, especially at high concentrations. Whereas D. melanogaster was repelled by high concentrations of these odors, D. sechellia was highly attracted. This was the case for odors presented singly, but more notably for blends thereof. Our study indicates that relatively simple changes, such as a shift in sensillar abundance, and concordant shifts in glomerular size, can distort the resulting olfactory code, and can lead to saltatory shifts in odor preference. D. sechellia has exploited this to align its olfactory preference with its ecological niche.

The perception of odor objects in everyday life: a review on the processing of odor mixtures

PubMed Central

Thomas-Danguin, Thierry; Sinding, Charlotte; Romagny, Sébastien; El Mountassir, Fouzia; Atanasova, Boriana; Le Berre, Elodie; Le Bon, Anne-Marie; Coureaud, Gérard

2014-01-01

Smelling monomolecular odors hardly ever occurs in everyday life, and the daily functioning of the sense of smell relies primarily on the processing of complex mixtures of volatiles that are present in the environment (e.g., emanating from food or conspecifics). Such processing allows for the instantaneous recognition and categorization of smells and also for the discrimination of odors among others to extract relevant information and to adapt efficiently in different contexts. The neurophysiological mechanisms underpinning this highly efficient analysis of complex mixtures of odorants is beginning to be unraveled and support the idea that olfaction, as vision and audition, relies on odor-objects encoding. This configural processing of odor mixtures, which is empirically subject to important applications in our societies (e.g., the art of perfumers, flavorists, and wine makers), has been scientifically studied only during the last decades. This processing depends on many individual factors, among which are the developmental stage, lifestyle, physiological and mood state, and cognitive skills; this processing also presents striking similarities between species. The present review gathers the recent findings, as observed in animals, healthy subjects, and/or individuals with affective disorders, supporting the perception of complex odor stimuli as odor objects. It also discusses peripheral to central processing, and cognitive and behavioral significance. Finally, this review highlights that the study of odor mixtures is an original window allowing for the investigation of daily olfaction and emphasizes the need for knowledge about the underlying biological processes, which appear to be crucial for our representation and adaptation to the chemical environment. PMID:24917831

Odorants and malodors associated with land application of biosolids stabilized with lime and coal fly ash.

PubMed

Laor, Yael; Naor, Moshe; Ravid, Uzi; Fine, Pinchas; Halachmi, Ilan; Chen, Yona; Baybikov, Rima

2011-01-01

Malodor emissions limit public acceptance of using municipal biosolids as natural organic resources in agricultural production. We aimed to identify major odorants and to evaluate odor concentrations associated with land application of anaerobically digested sewage sludges (Class B) and their alkaline (lime and coal fly ash)-stabilized products (Class A). These two types of biosolids were applied at 12.6 tonnes ha(-1) (dry weight) to microplots of very fine clayey Vertisol in the Jezreel Valley, northern Israel. The volatile organic compounds (VOCs) emitted from the biosolids before and during alkaline stabilization and after incorporation into the soil were analyzed by headspace solid-phase microextraction followed by gas chromatography-mass spectrometry. Odor concentrations at the plots were evaluated on site with a Nasal Ranger field olfactometer that sniffed over a defined land surface area through a static chamber. The odors emitted by anaerobically digested sewage sludges from three activated sludge water treatment plants had one characteristic chemical fingerprint. Alkaline stabilization emitted substantial odors associated with high concentrations of ammonia and release of nitrogen-containing VOCs and did not effectively reduce the potential odor annoyance. Odorous VOCs could be generated within the soil after biosolids incorporation, presumably because of anaerobic conditions within soil-biosolids aggregates. We propose that dimethyl disulfide and dimethyl trisulfide, which seem to be most related to the odor concentrations of biosolids-treated soil, be used as potential chemical markers for the odor annoyance associated with incorporation of anaerobically digested sewage sludges. by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Active Sampling State Dynamically Enhances Olfactory Bulb Odor Representation.

PubMed

Jordan, Rebecca; Fukunaga, Izumi; Kollo, Mihaly; Schaefer, Andreas T

2018-06-27

The olfactory bulb (OB) is the first site of synaptic odor information processing, yet a wealth of contextual and learned information has been described in its activity. To investigate the mechanistic basis of contextual modulation, we use whole-cell recordings to measure odor responses across rapid learning episodes in identified mitral/tufted cells (MTCs). Across these learning episodes, diverse response changes occur already during the first sniff cycle. Motivated mice develop active sniffing strategies across learning that robustly correspond to the odor response changes, resulting in enhanced odor representation. Evoking fast sniffing in different behavioral states demonstrates that response changes during active sampling exceed those predicted from feedforward input alone. Finally, response changes are highly correlated in tufted cells, but not mitral cells, indicating there are cell-type-specific effects on odor representation during active sampling. Altogether, we show that active sampling is strongly associated with enhanced OB responsiveness on rapid timescales. Copyright © 2018 The Francis Crick Institute. Published by Elsevier Inc. All rights reserved.

Age-associated loss of selectivity in human olfactory sensory neurons

PubMed Central

Rawson, Nancy E.; Gomez, George; Cowart, Beverly J.; Kriete, Andres; Pribitkin, Edmund; Restrepo, Diego

2011-01-01

We report a cross-sectional study of olfactory impairment with age based on both odorant-stimulated responses of human olfactory sensory neurons (OSNs) and tests of olfactory threshold sensitivity. A total of 621 OSNs from 440 subjects in two age groups of younger ( 45 years) and older (≥60 years) subjects were investigated using fluorescence intensity ratio fura-2 imaging. OSNs were tested for responses to two odorant mixtures, as well as to subsets of and individual odors in those mixtures. Whereas cells from younger donors were highly selective in the odorants to which they responded, cells from older donors were more likely to respond to multiple odor stimuli, despite a loss in these subjects’ absolute olfactory sensitivity, suggesting a loss of specificity. This degradation in peripheral cellular specificity may impact odor discrimination and olfactory adaptation in the elderly. It is also possible that chronic adaptation as a result of reduced specificity contributes to observed declines in absolute sensitivity. PMID:22074806

Identification of the genes involved in odorant reception and detection in the palm weevil Rhynchophorus ferrugineus, an important quarantine pest, by antennal transcriptome analysis.

PubMed

Antony, Binu; Soffan, Alan; Jakše, Jernej; Abdelazim, Mahmoud M; Aldosari, Saleh A; Aldawood, Abdulrahman S; Pain, Arnab

2016-01-22

The Red Palm Weevil (RPW) Rhynchophorus ferrugineus (Oliver) is one of the most damaging invasive insect species in the world. This weevil is highly specialized to thrive in adverse desert climates, and it causes major economic losses due to its effects on palm trees around the world. RPWs locate palm trees by means of plant volatile cues and use an aggregation pheromone to coordinate a mass-attack. Here we report on the high throughput sequencing of the RPW antennal transcriptome and present a description of the highly expressed chemosensory gene families. Deep sequencing and assembly of the RPW antennal transcriptome yielded 35,667 transcripts with an average length of 857 bp and identified a large number of highly expressed transcripts of odorant binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors/co-receptors (ORs/Orcos), sensory neuron membrane proteins (SNMPs), gustatory receptors (GRs) and ionotropic receptors (IRs). In total, 38 OBPs, 12 CSPs, 76 ORs, 1 Orco, 6 SNMPs, 15 GRs and 10 IRs were annotated in the R. ferrugineus antennal transcriptome. A comparative transcriptome analysis with the bark beetle showed that 25% of the blast hits were unique to R. ferrugineus, indicating a higher, more complete transcript coverage for R. ferrugineus. We categorized the RPW ORs into seven subfamilies of coleopteran ORs and predicted two new subfamilies of ORs. The OR protein sequences were compared with those of the flour beetle, the cerambycid beetle and the bark beetle, and we identified coleopteran-specific, highly conserved ORs as well as unique ORs that are putatively involved in RPW aggregation pheromone detection. We identified 26 Minus-C OBPs and 8 Plus-C OBPs and grouped R. ferrugineus OBPs into different OBP-subfamilies according to phylogeny, which indicated significant species-specific expansion and divergence in R. ferrugineus. We also identified a diverse family of CSP proteins, as well as a coleopteran-specific CSP lineage that diverged from Diptera and Lepidoptera. We identified several extremely diverged IR orthologues as well as highly conserved insect IR co-receptor orthologous transcripts in R. ferrugineus. Notably, GR orthologous transcripts for CO2-sensing and sweet tastants were identified in R. ferrugineus, and we found a great diversity of GRs within the coleopteran family. With respect to SNMP-1 and SNMP-2 orthologous transcripts, one SNMP-1 orthologue was found to be strikingly highly expressed in the R. ferrugineus antennal transcriptome. Our study presents the first comprehensive catalogue of olfactory gene families involved in pheromone and general odorant detection in R. ferrugineus, which are potential novel targets for pest control strategies.

Reminiscence therapy using odor in alcohol-dependent patients--psychophysiological evaluation and psychological evaluation; power spectral analysis of heart rate variability.

PubMed

Arizono, H; Morita, N; Iizuka, S; Satoh, S; Nakatani, Y

2000-12-01

This research was based on the hypothesis that when alcohol-dependent patients describe themselves, awakening of emotion by affirmative odor stimulation may facilitate memory reframing focusing on more affirmative emotion and memories. To prove the hypothesis, physiological changes accompanied by emotional awakening were evaluated by measuring the autonomic activity. In addition, subjective evaluation by a self-report manner was examined to investigate the effectiveness of Reminiscence Therapy (RT) using odor in alcohol-dependent patients. Thirty-four patients who met the DSM-IV criteria of alcohol-related disorders and were hospitalized in a ward specialized to alcohol dependence therapy. Each patient underwent a one-to-one interview twice. For counterbalance, one interview was performed with odor stimulation using an odor with a relaxing effect that recall pleasant emotion, and the other was without odor stimulation. As the evaluation indices of physiological changes accompanied by emotional awakening, index of autonomic function (HRV; Heart rate variability) for objective evaluation and psychological indices (STAI; State-Trait Anxiety Inventory VAS; Visual Analog Scale) for subjective evaluation were measured. 1) Objective evaluation: Regarding the evaluation index of the autonomic function, the sympathetic nervous system activity (LF/HF; low frequency component/high frequency component ratio) was significantly inhibited by odor stimulation (p < 0.05). 2) Subjective evaluation: Compared to the state prior to interview, state anxiety judged by STAI was significantly decreased after interview (p < 0.01). The VAS score was significantly decreased after interview regardless of the presence or absence of odor stimulation (p < 0.0001). A reduction in state anxiety was observed. The effect of odor was not significant on the subjective evaluation, but the objective evaluation suggested that the odor inhibited the sympathetic nervous system. Thus, it was suggested that odor can be used in RT, that is, emotional changes due to stimulation of odor may be applicable in RT.

Does human body odor represent a significant and rewarding social signal to individuals high in social openness?

PubMed

Lübke, Katrin T; Croy, Ilona; Hoenen, Matthias; Gerber, Johannes; Pause, Bettina M; Hummel, Thomas

2014-01-01

Across a wide variety of domains, experts differ from novices in their response to stimuli linked to their respective field of expertise. It is currently unknown whether similar patterns can be observed with regard to social expertise. The current study therefore focuses on social openness, a central social skill necessary to initiate social contact. Human body odors were used as social cues, as they inherently signal the presence of another human being. Using functional MRI, hemodynamic brain responses to body odors of women reporting a high (n = 14) or a low (n = 12) level of social openness were compared. Greater activation within the inferior frontal gyrus and the caudate nucleus was observed in high socially open individuals compared to individuals low in social openness. With the inferior frontal gyrus being a crucial part of the human mirror neuron system, and the caudate nucleus being implicated in social reward, it is discussed whether human body odor might constitute more of a significant and rewarding social signal to individuals high in social openness compared to individuals low in social openness process.

Relationship between 3-Methyl-2,4-nonanedione Concentration and Intensity of Light-induced Off-odor in Soy Bean Oil.

PubMed

Sano, Takashi; Iwahashi, Maiko; Imagi, Jun; Sato, Toshiro; Yamashita, Toshiyuki; Fukusaki, Eiichiro; Bamba, Takeshi

2016-05-01

A beany and green off-odor is developed in soy bean oil (SBO) under light-induced oxidative conditions. 3-Methyl-2,4-nonanedione (3-MND) was inferred as the compound responsible for the off-odor. In this study, we designed a simple quantification method for 3-MND in SBO, and evaluated the relationship between the 3-MND concentration and the intensity of the off-odor. 3-MND was analyzed by GC/MS with a thermal desorption unit system. By our method, the 3-MND concentration was found to increase with storage days and the SBO content under light exposure, and there was a high correlation between the measured 3-MND concentration and the intensity of the light-induced off-odor in SBO (R = 0.9586).

Effect of cysteine and cystine addition on sensory profile and potent odorants of extruded potato snacks.

PubMed

Majcher, Małgorzata A; Jeleń, Henryk H

2007-07-11

Aromas generated in extruded potato snacks without and with addition of 0.25, 0.5, and 1% (w/w) of flavor precursors, cysteine and cystine, were compared and evaluated by descriptive sensory profiling. The results showed that high addition of cysteine (0.5 and 1%) resulted in the formation of undesirable odor and taste described as mercaptanic/sulfur, onion-like, and bitter; on the contrary, addition of cystine even at high concentration gave product with pleasant odor and taste, slightly changed into breadlike notes. GC/O analysis showed cysteine to be a much more reactive flavor precursor than cystine, stimulating formation of 12 compounds with garlic, sulfury, burnt, pungent/beer, cabbage/mold, meatlike, roasted, and popcorn odor notes. Further analysis performed by the AEDA technique identified 2-methyl-3-furanthiol (FD 2048) as a most potent odorant of extruded potato snacks with 1% addition of cysteine. Other identified compounds with high FD were butanal, 3-methyl-2-butenethiol, 2-methylthiazole, methional, 2-acetyl-1-pyrroline, and 3-hydroxy-4,5-dimethyl-2(5H)-furanone. In the case of cystine addition (1%) the highest FD factors were calculated for butanal, 2-acetyl-1-pyrroline, benzenemethanethiol, methional, phenylacetaldehyde, dimethyltrisulfide, 1-octen-3-ol, 1,5-octadien-3-one, and 2-acetylpyrazine.

Identification of Ginger (Zingiber officinale Roscoe) Volatiles and Localization of Aroma-Active Constituents by GC-Olfactometry.

PubMed

Pang, Xueli; Cao, Jianmin; Wang, Dabin; Qiu, Jun; Kong, Fanyu

2017-05-24

For the characterization of chemical components contributing to the aroma of ginger, which could benefit the development of deep-processed ginger products, volatile extracts were isolated by a combination of direct solvent extraction-solvent-assisted flavor evaporation and static headspace analysis. Aroma-impact components were identified by gas chromatography-olfactometry-mass spectrometry, and the most potent odorants were further screened by aroma extract dilution analysis (AEDA) and static headspace dilution analysis (SHDA). The AEDA results revealed that geranial, eucalyptol, β-linalool, and bornyl acetate were the most potent odorants, exhibiting the highest flavor dilution factor (FD factor) of 2187. SHDA indicated that the predominant headspace odorants were α-pinene and eucalyptol. In addition, odorants exhibiting a high FD factor in SHDA were estimated to be potent aroma contributors in AEDA. The predominant odorants were found to be monoterpenes and sesquiterpenes, as along with their oxygenated derivatives, providing minty, lemon-like, herbal, and woody aromas. On the other hand, three highly volatile compounds detected by SHDA were not detected by AEDA, whereas 34 high-polarity, low-volatility compounds were identified only by AEDA, demonstrating the complementary natures of SHDA and AEDA and the necessity of utilizing both techniques to accurately characterize the aroma of ginger.

Orbital cortex neuronal responses during an odor-based conditioned associative task in rats.

PubMed

Yonemori, M; Nishijo, H; Uwano, T; Tamura, R; Furuta, I; Kawasaki, M; Takashima, Y; Ono, T

2000-01-01

Neuronal activity in the rat orbital cortex during discrimination of various odors [five volatile organic compounds (acetophenone, isoamyl acetate, cyclohexanone, p-cymene and 1,8-cineole), and food- and cosmetic-related odorants (black pepper, cheese, rose and perfume)] and other conditioned sensory stimuli (tones, light and air puff) was recorded and compared with behavioral responses to the same odors (black pepper, cheese, rose and perfume). In a neurophysiological study, the rats were trained to lick a spout that protruded close to its mouth to obtain sucrose or intracranial self-stimulation reward after presentation of conditioned stimuli. Of 150 orbital cortex neurons recorded during the task, 65 responded to one or more types of sensory stimuli. Of these, 73.8% (48/65) responded during presentation of an odor. Although the mean breadth of responsiveness (entropy) of the olfactory neurons based on the responses to five volatile organic compounds and air (control) was rather high (0.795), these stimuli were well discriminated in an odor space resulting from multidimensional scaling using Pearson's correlation coefficients between the stimuli. In a behavioral study, a rat was housed in an equilateral octagonal cage, with free access to food and choice among eight levers, four of which elicited only water (no odor, controls), and four of which elicited both water and one of four odors (black pepper, cheese, rose or perfume). Lever presses for each odor and control were counted. Distributions of these five stimuli (four odors and air) in an odor space derived from the multidimensional scaling using Pearson's correlation coefficients based on behavioral responses were very similar to those based on neuronal responses to the same five stimuli. Furthermore, Pearson's correlation coefficients between the same five stimuli based on the neuronal responses and those based on behavioral responses were significantly correlated. The results demonstrated a pivotal role of the rat orbital cortex in olfactory sensory processing and suggest that the orbital cortex is important in the manifestation of various motivated behaviors of the animals, including odor-guided motivational behaviors (odor preference).

Parallel processing via a dual olfactory pathway in the honeybee.

PubMed

Brill, Martin F; Rosenbaum, Tobias; Reus, Isabelle; Kleineidam, Christoph J; Nawrot, Martin P; Rössler, Wolfgang

2013-02-06

In their natural environment, animals face complex and highly dynamic olfactory input. Thus vertebrates as well as invertebrates require fast and reliable processing of olfactory information. Parallel processing has been shown to improve processing speed and power in other sensory systems and is characterized by extraction of different stimulus parameters along parallel sensory information streams. Honeybees possess an elaborate olfactory system with unique neuronal architecture: a dual olfactory pathway comprising a medial projection-neuron (PN) antennal lobe (AL) protocerebral output tract (m-APT) and a lateral PN AL output tract (l-APT) connecting the olfactory lobes with higher-order brain centers. We asked whether this neuronal architecture serves parallel processing and employed a novel technique for simultaneous multiunit recordings from both tracts. The results revealed response profiles from a high number of PNs of both tracts to floral, pheromonal, and biologically relevant odor mixtures tested over multiple trials. PNs from both tracts responded to all tested odors, but with different characteristics indicating parallel processing of similar odors. Both PN tracts were activated by widely overlapping response profiles, which is a requirement for parallel processing. The l-APT PNs had broad response profiles suggesting generalized coding properties, whereas the responses of m-APT PNs were comparatively weaker and less frequent, indicating higher odor specificity. Comparison of response latencies within and across tracts revealed odor-dependent latencies. We suggest that parallel processing via the honeybee dual olfactory pathway provides enhanced odor processing capabilities serving sophisticated odor perception and olfactory demands associated with a complex olfactory world of this social insect.

Application of PTR-MS for Measuring Odorant Emissions from Soil Application of Manure Slurry

PubMed Central

Feilberg, Anders; Bildsoe, Pernille; Nyord, Tavs

2015-01-01

Odorous volatile organic compounds (VOC) and hydrogen sulfide (H2S) are emitted together with ammonia (NH3) from manure slurry applied as a fertilizer, but little is known about the composition and temporal variation of the emissions. In this work, a laboratory method based on dynamic flux chambers packed with soil has been used to measure emissions from untreated pig slurry and slurry treated by solid-liquid separation and ozonation. Proton-transfer-reaction mass spectrometry (PTR-MS) was used to provide time resolved data for a range of VOC, NH3 and H2S. VOC included organic sulfur compounds, carboxylic acids, phenols, indoles, alcohols, ketones and aldehydes. H2S emission was remarkably observed to take place only in the initial minutes after slurry application, which is explained by its high partitioning into the air phase. Long-term odor effects are therefore assessed to be mainly due to other volatile compounds with low odor threshold values, such as 4-methylphenol. PTR-MS signal assignment was verified by comparison to a photo-acoustic analyzer (NH3) and to thermal desorption GC/MS (VOC). Due to initial rapid changes in odorant emissions and low concentrations of odorants, PTR-MS is assessed to be a very useful method for assessing odor following field application of slurry. The effects of treatments on odorant emissions are discussed. PMID:25585103

Accurate prediction of personalized olfactory perception from large-scale chemoinformatic features.

PubMed

Li, Hongyang; Panwar, Bharat; Omenn, Gilbert S; Guan, Yuanfang

2018-02-01

The olfactory stimulus-percept problem has been studied for more than a century, yet it is still hard to precisely predict the odor given the large-scale chemoinformatic features of an odorant molecule. A major challenge is that the perceived qualities vary greatly among individuals due to different genetic and cultural backgrounds. Moreover, the combinatorial interactions between multiple odorant receptors and diverse molecules significantly complicate the olfaction prediction. Many attempts have been made to establish structure-odor relationships for intensity and pleasantness, but no models are available to predict the personalized multi-odor attributes of molecules. In this study, we describe our winning algorithm for predicting individual and population perceptual responses to various odorants in the DREAM Olfaction Prediction Challenge. We find that random forest model consisting of multiple decision trees is well suited to this prediction problem, given the large feature spaces and high variability of perceptual ratings among individuals. Integrating both population and individual perceptions into our model effectively reduces the influence of noise and outliers. By analyzing the importance of each chemical feature, we find that a small set of low- and nondegenerative features is sufficient for accurate prediction. Our random forest model successfully predicts personalized odor attributes of structurally diverse molecules. This model together with the top discriminative features has the potential to extend our understanding of olfactory perception mechanisms and provide an alternative for rational odorant design.

Cognitive Load Alters Neuronal Processing of Food Odors.

PubMed

Hoffmann-Hensel, Sonja Maria; Sijben, Rik; Rodriguez-Raecke, Rea; Freiherr, Jessica

2017-10-31

Obesity is a major health concern in modern societies. Although decreased physical activity and enhanced intake of high-caloric foods are important risk factors for developing obesity, human behavior during eating also plays a role. Previous studies have shown that distraction while eating increases food intake and leads to impaired processing of food stimuli. As olfaction is the most important sense involved in flavor perception, we used functional magnetic resonance imaging techniques to investigate the influence of cognitive memory load on olfactory perception and processing. Low- and high-caloric food odors were presented in combination with either low or high cognitive loads utilizing a memory task. The efficacy of the memory task was verified by a decrease in participant recall accuracy and an increase in skin conductance response during high cognitive load. Our behavioral data reveal a diminished perceived intensity for low- but not high-caloric food odors during high cognitive load. For low-caloric food odors, bilateral orbitofrontal (OFC) and piriform cortices (pirC) showed significantly lower activity during high compared with low cognitive load. For high-caloric food odors, a similar effect was established in pirC, but not in OFC. Insula activity correlates with higher intensity ratings found during the low cognitive load condition. We conclude lower activity in pirC and OFC to be responsible for diminished intensity perception, comparable to results in olfactory impaired patients and elderly. Further studies should investigate the influence of olfactory/gustatory intensities on food choices under distraction with special regards to low-caloric food. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Semiquantitative determination of short-chain fatty acids in cane and beet sugars.

PubMed

Batista, Rebecca B; Grimm, Casey C; Godshall, Mary An

2002-03-01

Some sugars, specifically white beet sugar and raw cane sugars, possess off-flavors and off-odors. Although not necessarily the source, the presence of short-chain fatty acids serves as an indicator of an off-odor problem in sugar. Solid-phase microextraction (SPME) is used to collect the volatile compounds from the headspace of sugar. The temperature, moisture, and type of SPME fiber are varied to optimize recovery. Sugars analyzed in the absence of water using an incubation temperature of 70 degrees C with a divinylbenzene-carboxen-polydimethylsiloxane fiber yield the most reproducible results. Data from depletion analyses report a recovery level of 38% for the first injection. The semiquantitative analysis of butyric acid is accomplished using injected standards to develop a calibration curve.

Characteristic aroma components of rennet casein.

PubMed

Karagül-Yüceer, Yonca; Vlahovich, Katrina N; Drake, MaryAnne; Cadwallader, Keith R

2003-11-05

Rennet casein, produced by enzymatic (rennet) precipitation of casein from pasteurized skim milk, is used in both industrial (technical) and food applications. The flavor of rennet casein powder is an important quality parameter; however, the product often contains an odor described as like that of animal/wet dog. Two commercial rennet casein powders were evaluated to determine the compounds responsible for the typical odor. Aroma extracts were prepared by high-vacuum distillation of direct solvent (ether) extracts and analyzed by gas chromatography-olfactometry (GCO), aroma extract dilution analysis (AEDA), and GC-mass spectrometry (MS). Odorants detected by GCO were typical of those previously reported in skim milk powders and consisted mainly of short-chain volatile acids, phenolic compounds, lactones, and furanones. Results of AEDA indicated o-aminoacetophenone to be a potent odorant; however, sensory descriptive sensory analysis of model aroma systems revealed that the typical odor of rennet casein was principally caused by hexanoic acid, indole, guaiacol, and p-cresol.

Two Parallel Olfactory Pathways for Processing General Odors in a Cockroach

PubMed Central

Watanabe, Hidehiro; Nishino, Hiroshi; Mizunami, Makoto; Yokohari, Fumio

2017-01-01

In animals, sensory processing via parallel pathways, including the olfactory system, is a common design. However, the mechanisms that parallel pathways use to encode highly complex and dynamic odor signals remain unclear. In the current study, we examined the anatomical and physiological features of parallel olfactory pathways in an evolutionally basal insect, the cockroach Periplaneta americana. In this insect, the entire system for processing general odors, from olfactory sensory neurons to higher brain centers, is anatomically segregated into two parallel pathways. Two separate populations of secondary olfactory neurons, type1 and type2 projection neurons (PNs), with dendrites in distinct glomerular groups relay olfactory signals to segregated areas of higher brain centers. We conducted intracellular recordings, revealing olfactory properties and temporal patterns of both types of PNs. Generally, type1 PNs exhibit higher odor-specificities to nine tested odorants than type2 PNs. Cluster analyses revealed that odor-evoked responses were temporally complex and varied in type1 PNs, while type2 PNs exhibited phasic on-responses with either early or late latencies to an effective odor. The late responses are 30–40 ms later than the early responses. Simultaneous intracellular recordings from two different PNs revealed that a given odor activated both types of PNs with different temporal patterns, and latencies of early and late responses in type2 PNs might be precisely controlled. Our results suggest that the cockroach is equipped with two anatomically and physiologically segregated parallel olfactory pathways, which might employ different neural strategies to encode odor information. PMID:28529476

Characterization of odorants causing an atypical aroma in white pepper powder (Piper nigrum L.) based on quantitative measurements and orthonasal breakthrough thresholds.

PubMed

Steinhaus, Martin; Schieberle, Peter

2005-07-27

Application of the aroma extract dilution analysis on an extract of white pepper powder showing an intense fecal, cowshed-like off-flavor revealed 3-methylindole (fecal, swine-manure) and 4-methylphenol (fecal, horse-like) with the highest flavor dilution (FD) factors among the 22 odor-active compounds detected. In addition, high FD factors and/or undesirable odor qualities suggested 3-methylphenol (phenolic), butanoic acid (cheese-like), and 2- and 3-methylbutanoic acid (cheese-like) as well as pentanoic acid and hexanoic acid (cheese-like odors) as contributors to the malodor. Although the intensities of the off-note were clearly different in 50 commercial samples of white pepper, quantitation of 3-methylindole and 3- and 4-methylphenol as well as of the five short-chain acids by means of stable isotope dilution assays showed similar concentrations in most of the samples. Storage of a freshly ground white pepper powder for up to 7 months revealed a significant decrease in the typical odor qualities of white pepper and an increase in the fecal odor note with storage time. Because the concentrations of the odorants mentioned above were not much changed during storage, possibly very volatile odorants, such as alpha-pinene, which are able to mask the malodor, are lost during storage of, in particular, pepper powders. On the basis of odor activity values, which were calculated using breakthrough thresholds, in particular, 3-methylindole, 4-methylphenol, 3-methylphenol, and butanoic acid could be suggested as the main sources of the fecal off-flavor.

Resolving the chemical structures of off-odorants and potentially harmful substances in toys-example of children's swords.

PubMed

Denk, Philipp; Velasco-Schön, Cristina; Buettner, Andrea

2017-09-01

Most children's toys on the market are primarily made out of plastic and other complex composite materials. Consumer complaints about offensive odors or irritating effects associated with toy products have increased in recent years. One example is the strongly perceivable negative odor reported for a particular series of toy swords. Characterizing the presence of contaminants, including those that have the potential to be deleterious to health, in such products is a significant analytical challenge due to the high baseline abundance of chemical constituents of the materials used in the products. In the present study, the nature of offensive odorants associated with toy sword products was examined by gas chromatography (GC). After initial sensory evaluations, the volatile compounds from the toy products were recovered using solvent extraction and solvent-assisted flavor evaporation. The extracts were analyzed using GC-olfactometry (GC-O) and two-dimensional GC-O coupled with mass spectrometry (GC-GC-MS/O). A total of 26 odor-active compounds, including aromatic hydrocarbons and phenols, were identified among numerous non-odorous volatile by-products. These substances also included polycyclic aromatic hydrocarbons, which were analyzed by GC-MS. Representative substances were naphthalene and 1,2-dihydronaphthalene that exhibited moldy, mothball-like odor impressions, and phenol derivatives with leather-like, phenolic, horse-stable-like smells. The odorants detected correlated with the assigned attributes from the sensory analyses. This study clearly shows that the detection and identification of such odorous contaminants can provide key indications of potentially harmful yet unknown substances in everyday products such as toys. Graphical abstract ᅟ.

Sampling Technique for Robust Odorant Detection Based on MIT RealNose Data

NASA Technical Reports Server (NTRS)

Duong, Tuan A.

2012-01-01

This technique enhances the detection capability of the autonomous Real-Nose system from MIT to detect odorants and their concentrations in noisy and transient environments. The lowcost, portable system with low power consumption will operate at high speed and is suited for unmanned and remotely operated long-life applications. A deterministic mathematical model was developed to detect odorants and calculate their concentration in noisy environments. Real data from MIT's NanoNose was examined, from which a signal conditioning technique was proposed to enable robust odorant detection for the RealNose system. Its sensitivity can reach to sub-part-per-billion (sub-ppb). A Space Invariant Independent Component Analysis (SPICA) algorithm was developed to deal with non-linear mixing that is an over-complete case, and it is used as a preprocessing step to recover the original odorant sources for detection. This approach, combined with the Cascade Error Projection (CEP) Neural Network algorithm, was used to perform odorant identification. Signal conditioning is used to identify potential processing windows to enable robust detection for autonomous systems. So far, the software has been developed and evaluated with current data sets provided by the MIT team. However, continuous data streams are made available where even the occurrence of a new odorant is unannounced and needs to be noticed by the system autonomously before its unambiguous detection. The challenge for the software is to be able to separate the potential valid signal from the odorant and from the noisy transition region when the odorant is just introduced.

Right Occipital Cortex Activation Correlates with Superior Odor Processing Performance in the Early Blind

PubMed Central

Grandin, Cécile B.; Dricot, Laurence; Plaza, Paula; Lerens, Elodie; Rombaux, Philippe; De Volder, Anne G.

2013-01-01

Using functional magnetic resonance imaging (fMRI) in ten early blind humans, we found robust occipital activation during two odor-processing tasks (discrimination or categorization of fruit and flower odors), as well as during control auditory-verbal conditions (discrimination or categorization of fruit and flower names). We also found evidence for reorganization and specialization of the ventral part of the occipital cortex, with dissociation according to stimulus modality: the right fusiform gyrus was most activated during olfactory conditions while part of the left ventral lateral occipital complex showed a preference for auditory-verbal processing. Only little occipital activation was found in sighted subjects, but the same right-olfactory/left-auditory-verbal hemispheric lateralization was found overall in their brain. This difference between the groups was mirrored by superior performance of the blind in various odor-processing tasks. Moreover, the level of right fusiform gyrus activation during the olfactory conditions was highly correlated with individual scores in a variety of odor recognition tests, indicating that the additional occipital activation may play a functional role in odor processing. PMID:23967263

Identification of predominant odorants in thai desserts flavored by smoking with "Tian Op", a traditional Thai scented candle.

PubMed

Watcharananun, Wanwarang; Cadwallader, Keith R; Huangrak, Kittiphong; Kim, Hun; Lorjaroenphon, Yaowapa

2009-02-11

"Tian Op", a traditional Thai scented candle, is used for the smoking and flavoring of sweets, cakes, and other desserts for the purpose of adding a unique aroma to the final product. Gas chromatography-olfactometry, aroma extract dilution analysis, and GC-MS were applied to identify the potent odorants in two types of traditional Thai desserts ("num dok mai" and "gleep lum duan") prepared using a Tian Op smoking process. On the basis of the results of AEDA and calculated odor-activity values, the predominant odorants in the Tian Op flavored desserts were vinyl ketones (C(5)-C(9)), n-aldehydes (C(5)-C(11)), (E)-2-unsaturated aldehydes (C(8)-C(11)), and omega-1-unsaturated aldehydes (C(8) and C(9)). Sensory studies of model mixtures confirmed the importance of n-aldehydes, omega-1-unsaturated aldehydes, and guaiacol as predominant odorants; however, the results showed that vinyl ketones and (E)-2-unsaturated aldehydes, despite having high odor-activity values, may be of only minor importance in the typical aroma profiles of traditional Tian Op smoked desserts.

Failure to Find Ethanol-Induced Conditioned Taste Aversion in Honey Bees (Apis mellifera L.).

PubMed

Varnon, Christopher A; Dinges, Christopher W; Black, Timothy E; Wells, Harrington; Abramson, Charles I

2018-04-24

Conditioned taste aversion (CTA) learning is a highly specialized form of conditioning found across taxa that leads to avoidance of an initially neutral stimulus, such as taste or odor, that is associated with, but is not the cause of, a detrimental health condition. This study examines if honey bees (Apis mellifera L.) develop ethanol (EtOH)-induced CTA. Restrained bees were first administered a sucrose solution that was cinnamon scented, lavender scented, or unscented, and contained either 0, 2.5, 5, 10, or 20% EtOH. Then, 30 minutes later, we used a proboscis extension response (PER) conditioning procedure where the bees were taught to associate either cinnamon odor, lavender odor, or an air-puff with repeated sucrose feedings. For some bees, the odor of the previously consumed EtOH solution was the same as the odor associated with sucrose in the conditioning procedure. If bees are able to learn EtOH-induced CTA, they should show an immediate low level of response to odors previously associated with EtOH. We found that bees did not develop CTA despite the substantial inhibitory and aversive effects EtOH has on behavior. Instead, bees receiving a conditioning odor that was previously associated with EtOH showed an immediate high level of response. While this demonstrates bees are capable of one-trial learning common to CTA experiments, this high level of response is the opposite of what would occur if the bees developed a CTA. Responding on subsequent trials also showed a general inhibitory effect of EtOH. Finally, we found that consumption of cinnamon extract reduced the effects of EtOH. The honey bees' lack of learned avoidance to EtOH mirrors that seen in human alcoholism. These findings demonstrate the usefulness of honey bees as an insect model for EtOH consumption. Copyright © 2018 by the Research Society on Alcoholism.

Nosema ceranae parasitism impacts olfactory learning and memory and neurochemistry in honey bees (Apis mellifera).

PubMed

Gage, Stephanie L; Kramer, Catherine; Calle, Samantha; Carroll, Mark; Heien, Michael; DeGrandi-Hoffman, Gloria

2018-02-19

Nosema sp. is an internal parasite of the honey bee, Apis mellifera , and one of the leading contributors to colony losses worldwide. This parasite is found in the honey bee midgut and has profound consequences for the host's physiology. Nosema sp. impairs foraging performance in honey bees, yet, it is unclear whether this parasite affects the bee's neurobiology. In this study, we examined whether Nosema sp. affects odor learning and memory and whether the brains of parasitized bees show differences in amino acids and biogenic amines. We took newly emerged bees and fed them with Nosema ceranae At approximate nurse and forager ages, we employed an odor-associative conditioning assay using the proboscis extension reflex and two bioanalytical techniques to measure changes in brain chemistry. We found that nurse-aged bees infected with N. ceranae significantly outperformed controls in odor learning and memory, suggestive of precocious foraging, but by forager age, infected bees showed deficits in learning and memory. We also detected significant differences in amino acid concentrations, some of which were age specific, as well as altered serotonin, octopamine, dopamine and l-dopa concentrations in the brains of parasitized bees. These findings suggest that N. ceranae infection affects honey bee neurobiology and may compromise behavioral tasks. These results yield new insight into the host-parasite dynamic of honey bees and N. ceranae , as well as the neurochemistry of odor learning and memory under normal and parasitic conditions. © 2018. Published by The Company of Biologists Ltd.

Olfactory discrimination ability of CD-1 mice for a large array of enantiomers.

PubMed

Laska, M; Shepherd, G M

2007-01-05

With use of a conditioning paradigm, the ability of eight CD-1 mice to distinguish between 15 enantiomeric odor pairs was investigated. The results demonstrate a) that CD-1 mice are capable of discriminating between all odor pairs tested, b) that the enantiomeric odor pairs clearly differed in their degree of discriminability and thus in their perceptual similarity, and c) that pre-training with the rewarded stimuli led to improved initial but not terminal or overall performance. A comparison between the proportion of discriminated enantiomeric odor pairs of the CD-1 mice and those of other species tested in earlier studies on the same discrimination tasks (or on subsets thereof) shows a significant positive correlation between discrimination performance and the number of functional olfactory receptor genes. These findings provide the first evidence of a highly developed ability of CD-1 mice to discriminate between an array of non-pheromonal chiral odorants. Further, they suggest that a species' olfactory discrimination capabilities for these odorants may be correlated with its number of functional olfactory receptor genes. The data presented here may provide useful information for the interpretation of findings from electrophysiological or imaging studies in the mouse and the elucidation of odor structure-activity relationships.

Olfactory discrimination ability of CD-1 mice for a large array of enantiomers

PubMed Central

Laska, Matthias; Shepherd, Gordon M.

2006-01-01

With use of a conditioning paradigm, the ability of eight CD-1 mice to distinguish between 15 enantiomeric odor pairs was investigated. The results demonstrate a) that CD-1 mice are capable of discriminating between all odor pairs tested, b) that the enantiomeric odor pairs clearly differed in their degree of discriminability and thus in their perceptual similarity, and c) that pre-training with the rewarded stimuli led to improved initial but not terminal or overall performance. A comparison between the proportion of discriminated enantiomeric odor pairs of the CD-1 mice and those of other species tested in earlier studies on the same discrimination tasks (or on subsets thereof) shows a significant positive correlation between discrimination performance and the number of functional olfactory receptor genes. These findings provide the first evidence of a highly developed ability of CD-1 mice to discriminate between an array of non-pheromonal chiral odorants. Further, they suggest that a species′ olfactory discrimination capabilities for these odorants may be correlated with its number of functional olfactory receptor genes. The data presented here may provide useful information for the interpretation of findings from electrophysiological or imaging studies in the mouse and the elucidation of odor structure-activity relationships. PMID:17045753

Role of Self-Generated Odor Cues in Contextual Representation

PubMed Central

Aikath, Devdeep; Weible, Aldis P; Rowland, David C; Kentros, Clifford G

2014-01-01

As first demonstrated in the patient H.M., the hippocampus is critically involved in forming episodic memories, the recall of “what” happened “where” and “when.” In rodents, the clearest functional correlate of hippocampal primary neurons is the place field: a cell fires predominantly when the animal is in a specific part of the environment, typically defined relative to the available visuospatial cues. However, rodents have relatively poor visual acuity. Furthermore, they are highly adept at navigating in total darkness. This raises the question of how other sensory modalities might contribute to a hippocampal representation of an environment. Rodents have a highly developed olfactory system, suggesting that cues such as odor trails may be important. To test this, we familiarized mice to a visually cued environment over a number of days while maintaining odor cues. During familiarization, self-generated odor cues unique to each animal were collected by re-using absorbent paperboard flooring from one session to the next. Visual and odor cues were then put in conflict by counter-rotating the recording arena and the flooring. Perhaps surprisingly, place fields seemed to follow the visual cue rotation exclusively, raising the question of whether olfactory cues have any influence at all on a hippocampal spatial representation. However, subsequent removal of the familiar, self-generated odor cues severely disrupted both long-term stability and rotation to visual cues in a novel environment. Our data suggest that odor cues, in the absence of additional rule learning, do not provide a discriminative spatial signal that anchors place fields. Such cues do, however, become integral to the context over time and exert a powerful influence on the stability of its hippocampal representation. © 2014 The Authors. Hippocampus Published by Wiley Periodicals, Inc. PMID:24753119

Appetitive but not aversive olfactory conditioning modifies antennal movements in honeybees

PubMed Central

Cholé, Hanna; Junca, Pierre

2015-01-01

In honeybees, two olfactory conditioning protocols allow the study of appetitive and aversive Pavlovian associations. Appetitive conditioning of the proboscis extension response (PER) involves associating an odor, the conditioned stimulus (CS) with a sucrose solution, the unconditioned stimulus (US). Conversely, aversive conditioning of the sting extension response (SER) involves associating the odor CS with an electric or thermal shock US. Each protocol is based on the measure of a different behavioral response (proboscis versus sting) and both only provide binary responses (extension or not of the proboscis or sting). These limitations render the measure of the acquired valence of an odor CS difficult without testing the animals in a freely moving situation. Here, we studied the effects of both olfactory conditioning protocols on the movements of the antennae, which are crucial sensory organs for bees. As bees’ antennae are highly mobile, we asked whether their movements in response to an odorant change following appetitive or aversive conditioning and if so, do odor-evoked antennal movements contain information about the acquired valence of the CS? We implemented a tracking system for harnessed bees’ antennal movements based on a motion capture principle at a high frequency rate. We observed that differential appetitive conditioning had a strong effect on antennal movements. Bees responded to the reinforced odorant with a marked forward motion of the antennae and a strong velocity increase. Conversely, differential aversive conditioning had no associative effect on antennal movements. Rather than revealing the acquired valence of an odorant, antennal movements may represent a novel conditioned response taking place during appetitive conditioning and may provide a possible advantage to bees when foraging in natural situations. PMID:26572651

Chemical and sensorial aroma characterization of freshly distilled Calvados. 1. Evaluation of quality and defects on the basis of key odorants by olfactometry and sensory analysis.

PubMed

Guichard, Hugues; Lemesle, Stéphane; Ledauphin, Jérôme; Barillier, Daniel; Picoche, Bernard

2003-01-15

Eight freshly distilled samples of Calvados, a fermented and distilled apple juice, were analyzed by sensory evaluation and direct injection GC to determine the composition of higher alcohols, esters, and aldehydes. The composition determined by direct injection was tentatively related to sensory descriptors. Esters have a probable maximum level around 500 g/hl of pure alcohol (PA). This level also corresponds to the threshold of the main ester constituent, ethyl acetate. A high ratio of esters to ethyl acetate seems to be of prime importance for good quality. Total aldehydes, with a maximum level between 8 and 11 g/hl of PA and mainly comprising acetal (maximum between 5 and 9 g/hl of PA), were related to a "green" descriptor. Higher alcohols do not have a direct impact on quality, but other volatile compounds with a positive impact on flavor should probably be present at a high level. As overall quality was not well related to sensory quality, it was necessary to perform more a precise analysis to determine the key odorants. The Calvados samples were thus extracted using pentane. Gas chromatography, employing both a flame ionization detector and an olfactometry port, was used to analyze the obtained extracts. Seventy-one odors were detected and distributed according to Calvados quality determined by sensory evaluation. Nineteen odors common to all Calvados samples constituted the "skeleton" of the aroma. Twenty-eight odors were specific to a quality class: 6 for good quality, 4 for neutral, and 18 for defective. Twenty-four other odors had either too low an odor impact or no evident specificity.

Comparison of glomerular activity patterns by fMRI and wide-field calcium imaging: implications for principles underlying odor mapping

PubMed Central

Sanganahalli, Basavaraju G.; Rebello, Michelle R.; Herman, Peter; Papademetris, Xenophon; Shepherd, Gordon M.; Verhagen, Justus V.; Hyder, Fahmeed

2015-01-01

Functional imaging signals arise from distinct metabolic and hemodynamic events at the neuropil, but how these processes are influenced by pre- and post-synaptic activities need to be understood for quantitative interpretation of stimulus-evoked mapping data. The olfactory bulb (OB) glomeruli, spherical neuropil regions with well-defined neuronal circuitry, can provide insights into this issue. Optical calcium-sensitive fluorescent dye imaging (OICa2+) reflects dynamics of pre-synaptic input to glomeruli, whereas high-resolution functional magnetic resonance imaging (fMRI) using deoxyhemoglobin contrast reveals neuropil function within the glomerular layer where both pre- and post-synaptic activities contribute. We imaged odor-specific activity patterns of the dorsal OB in the same anesthetized rats with fMRI and OICa2+ and then co-registered the respective maps to compare patterns in the same space. Maps by each modality were very reproducible as trial-to-trial patterns for a given odor, overlapping by ~80%. Maps evoked by ethyl butyrate and methyl valerate for a given modality overlapped by ~80%, suggesting activation of similar dorsal glomerular networks by these odors. Comparison of maps generated by both methods for a given odor showed ~70% overlap, indicating similar odor-specific maps by each method. These results suggest that odor-specific glomerular patterns by high-resolution fMRI primarily tracks pre-synaptic input to the OB. Thus combining OICa2+ and fMRI lays the framework for studies of OB processing over a range of spatiotemporal scales, where OICa2+ can feature the fast dynamics of dorsal glomerular clusters and fMRI can map the entire glomerular sheet in the OB. PMID:26631819

Sadness might isolate you in a non-smelling world: olfactory perception and depression

PubMed Central

Schablitzky, Sylvia; Pause, Bettina M.

2014-01-01

Major depressive disorder (MDD) occurs with a high prevalence among mental illnesses. MDD patients experience sadness and hopelessness, with blunted affective reactivity. However, such depressive episodes are also key symptoms in other depressive disorders, like Bipolar Disorder (BPD) or Seasonal Affective Disorder (SAD). Moreover, depressive symptoms can also be found in healthy individuals, but are experienced as less severe or for a shorter duration than in patients. Here, it is aimed to summarize studies investigating odor perception in depression, including depressive states in healthy individuals and patient populations. Odor perception in depression has been assessed with psychophysical methods (olfactory sensitivity, odor identification, and discrimination), and odor ratings (intensity, emotional valence, familiarity). In addition, some studies investigated affective reactions to odors, and physiological and anatomical correlates of odor perception in depression. The summary reveals that MDD is associated with reduced olfactory sensitivity. However, odor identification and discrimination scores seem to be unaffected by depression. The reduced olfactory sensitivity might be associated with a reduced ability to encode olfactory information and a reduced volume of the olfactory bulb. While similar processes seem to occur in healthy individuals experiencing depressive states, they have not been observed in BPD or SAD patients. However, in order to conclude that the reduced olfactory sensitivity is directly linked to depression, it is suggested that studies should implement control measures of cognitive performances or perceptual abilities in other stimulus modalities. It is concluded that the reduced olfactory performance in MDD patients seems to be disorder-, modality-, and test-specific, and that the application of an appropriate olfactory and cognitive test-battery might be highly useful in the differential diagnosis of MDD. PMID:24570666

Does Human Body Odor Represent a Significant and Rewarding Social Signal to Individuals High in Social Openness?

PubMed Central

Lübke, Katrin T.; Croy, Ilona; Hoenen, Matthias; Gerber, Johannes; Pause, Bettina M.; Hummel, Thomas

2014-01-01

Across a wide variety of domains, experts differ from novices in their response to stimuli linked to their respective field of expertise. It is currently unknown whether similar patterns can be observed with regard to social expertise. The current study therefore focuses on social openness, a central social skill necessary to initiate social contact. Human body odors were used as social cues, as they inherently signal the presence of another human being. Using functional MRI, hemodynamic brain responses to body odors of women reporting a high (n = 14) or a low (n = 12) level of social openness were compared. Greater activation within the inferior frontal gyrus and the caudate nucleus was observed in high socially open individuals compared to individuals low in social openness. With the inferior frontal gyrus being a crucial part of the human mirror neuron system, and the caudate nucleus being implicated in social reward, it is discussed whether human body odor might constitute more of a significant and rewarding social signal to individuals high in social openness compared to individuals low in social openness process. PMID:24718308

Development of Fabric-Based Chemical Gas Sensors for Use as Wearable Electronic Noses

PubMed Central

Seesaard, Thara; Lorwongtragool, Panida; Kerdcharoen, Teerakiat

2015-01-01

Novel gas sensors embroidered into fabric substrates based on polymers/ SWNT-COOH nanocomposites were proposed in this paper, aiming for their use as a wearable electronic nose (e-nose). The fabric-based chemical gas sensors were fabricated by two main processes: drop coating and embroidery. Four potential polymers (PVC, cumene-PSMA, PSE and PVP)/functionalized-SWCNT sensing materials were deposited onto interdigitated electrodes previously prepared by embroidering conductive thread on a fabric substrate to make an optimal set of sensors. After preliminary trials of the obtained sensors, it was found that the sensors yielded a electrical resistance in the region of a few kilo-Ohms. The sensors were tested with various volatile compounds such as ammonium hydroxide, ethanol, pyridine, triethylamine, methanol and acetone, which are commonly found in the wastes released from the human body. These sensors were used to detect and discriminate between the body odors of different regions and exist in various forms such as the urine, armpit and exhaled breath odor. Based on a simple pattern recognition technique, we have shown that the proposed fabric-based chemical gas sensors can discriminate the human body odor from two persons. PMID:25602265

Development of fabric-based chemical gas sensors for use as wearable electronic noses.

PubMed

Seesaard, Thara; Lorwongtragool, Panida; Kerdcharoen, Teerakiat

2015-01-16

Novel gas sensors embroidered into fabric substrates based on polymers/ SWNT-COOH nanocomposites were proposed in this paper, aiming for their use as a wearable electronic nose (e-nose). The fabric-based chemical gas sensors were fabricated by two main processes: drop coating and embroidery. Four potential polymers (PVC, cumene-PSMA, PSE and PVP)/functionalized-SWCNT sensing materials were deposited onto interdigitated electrodes previously prepared by embroidering conductive thread on a fabric substrate to make an optimal set of sensors. After preliminary trials of the obtained sensors, it was found that the sensors yielded a electrical resistance in the region of a few kilo-Ohms. The sensors were tested with various volatile compounds such as ammonium hydroxide, ethanol, pyridine, triethylamine, methanol and acetone, which are commonly found in the wastes released from the human body. These sensors were used to detect and discriminate between the body odors of different regions and exist in various forms such as the urine, armpit and exhaled breath odor. Based on a simple pattern recognition technique, we have shown that the proposed fabric-based chemical gas sensors can discriminate the human body odor from two persons.

Improved utilization of fish waste by anaerobic digestion following omega-3 fatty acids extraction.

PubMed

Nges, Ivo Achu; Mbatia, Betty; Björnsson, Lovisa

2012-11-15

Fish waste is a potentially valuable resource from which high-value products can be obtained. Anaerobic digestion of the original fish waste and the fish sludge remaining after enzymatic pre-treatment to extract fish oil and fish protein hydrolysate was evaluated regarding the potential for methane production. The results showed high biodegradability of both fish sludge and fish waste, giving specific methane yields of 742 and 828 m(3)CH(4)/tons VS added, respectively. However, chemical analysis showed high concentrations of light metals which, together with high fat and protein contents, could be inhibitory to methanogenic bacteria. The feasibility of co-digesting the fish sludge with a carbohydrate-rich residue from crop production was thus investigated, and a full-scale process outlined for converting odorous fish waste to useful products. Copyright © 2012 Elsevier Ltd. All rights reserved.

Aversive learning of odor-heat associations in ants.

PubMed

Desmedt, Lucie; Baracchi, David; Devaud, Jean-Marc; Giurfa, Martin; d'Ettorre, Patrizia

2017-12-15

Ants have recently emerged as useful models for the study of olfactory learning. In this framework, the development of a protocol for the appetitive conditioning of the maxilla-labium extension response (MaLER) provided the possibility of studying Pavlovian odor-food learning in a controlled environment. Here we extend these studies by introducing the first Pavlovian aversive learning protocol for harnessed ants in the laboratory. We worked with carpenter ants Camponotus aethiops and first determined the capacity of different temperatures applied to the body surface to elicit the typical aversive mandible opening response (MOR). We determined that 75°C is the optimal temperature to induce MOR and chose the hind legs as the stimulated body region because of their high sensitivity. We then studied the ability of ants to learn and remember odor-heat associations using 75°C as the unconditioned stimulus. We studied learning and short-term retention after absolute (one odor paired with heat) and differential conditioning (a punished odor versus an unpunished odor). Our results show that ants successfully learn the odor-heat association under a differential-conditioning regime and thus exhibit a conditioned MOR to the punished odor. Yet, their performance under an absolute-conditioning regime is poor. These results demonstrate that ants are capable of aversive learning and confirm previous findings about the different attentional resources solicited by differential and absolute conditioning in general. © 2017. Published by The Company of Biologists Ltd.

Olfactory discrimination largely persists in mice with defects in odorant receptor expression and axon guidance.

PubMed

Knott, Thomas K; Madany, Pasil A; Faden, Ashley A; Xu, Mei; Strotmann, Jörg; Henion, Timothy R; Schwarting, Gerald A

2012-07-04

The defining feature of the main olfactory system in mice is that each olfactory sensory neuron expresses only one of more than a thousand different odorant receptor genes. Axons expressing the same odorant receptor converge onto a small number of targets in the olfactory bulb such that each glomerulus is made up of axon terminals expressing just one odorant receptor. It is thought that this precision in axon targeting is required to maintain highly refined odor discrimination. We previously showed that β3GnT2(-/-) mice have severe developmental and axon guidance defects. The phenotype of these mice is similar to adenylyl cyclase 3 (AC3) knockout mice largely due to the significant down-regulation of AC3 activity in β3GnT2(-/-) neurons. Microarray analysis reveals that nearly one quarter of all odorant receptor genes are down regulated in β3GnT2(-/-) mice compared to controls. Analysis of OR expression by quantitative PCR and in situ hybridization demonstrates that the number of neurons expressing some odorant receptors, such as mOR256-17, is increased by nearly 60% whereas for others such as mOR28 the number of neurons is decreased by more than 75% in β3GnT2(-/-) olfactory epithelia. Analysis of axon trajectories confirms that many axons track to inappropriate targets in β3GnT2(-/-) mice, and some glomeruli are populated by axons expressing more than one odorant receptor. Results show that mutant mice perform nearly as well as control mice in an odor discrimination task. In addition, in situ hybridization studies indicate that the expression of several activity dependent genes is unaffected in β3GnT2(-/-) olfactory neurons. Results presented here show that many odorant receptors are under-expressed in β3GnT2(-/-) mice and further demonstrate that additional axon subsets grow into inappropriate targets or minimally innervate glomeruli in the olfactory bulb. Odor evoked gene expression is unchanged and β3GnT2(-/-) mice exhibit a relatively small deficit in their ability to discriminate divergent odors. Results suggest that despite the fact that β3GnT2(-/-) mice have decreased AC3 activity, decreased expression of many ORs, and display many axon growth and guidance errors, odor-evoked activity in cilia of mutant olfactory neurons remains largely intact.

Large-scale production and study of a synthetic G protein-coupled receptor: Human olfactory receptor 17-4

PubMed Central

Cook, Brian L.; Steuerwald, Dirk; Kaiser, Liselotte; Graveland-Bikker, Johanna; Vanberghem, Melanie; Berke, Allison P.; Herlihy, Kara; Pick, Horst; Vogel, Horst; Zhang, Shuguang

2009-01-01

Although understanding of the olfactory system has progressed at the level of downstream receptor signaling and the wiring of olfactory neurons, the system remains poorly understood at the molecular level of the receptors and their interaction with and recognition of odorant ligands. The structure and functional mechanisms of these receptors still remain a tantalizing enigma, because numerous previous attempts at the large-scale production of functional olfactory receptors (ORs) have not been successful to date. To investigate the elusive biochemistry and molecular mechanisms of olfaction, we have developed a mammalian expression system for the large-scale production and purification of a functional OR protein in milligram quantities. Here, we report the study of human OR17-4 (hOR17-4) purified from a HEK293S tetracycline-inducible system. Scale-up of production yield was achieved through suspension culture in a bioreactor, which enabled the preparation of >10 mg of monomeric hOR17-4 receptor after immunoaffinity and size exclusion chromatography, with expression yields reaching 3 mg/L of culture medium. Several key post-translational modifications were identified using MS, and CD spectroscopy showed the receptor to be ≈50% α-helix, similar to other recently determined G protein-coupled receptor structures. Detergent-solubilized hOR17-4 specifically bound its known activating odorants lilial and floralozone in vitro, as measured by surface plasmon resonance. The hOR17-4 also recognized specific odorants in heterologous cells as determined by calcium ion mobilization. Our system is feasible for the production of large quantities of OR necessary for structural and functional analyses and research into OR biosensor devices. PMID:19581598

Large-scale production and study of a synthetic G protein-coupled receptor: human olfactory receptor 17-4.

PubMed

Cook, Brian L; Steuerwald, Dirk; Kaiser, Liselotte; Graveland-Bikker, Johanna; Vanberghem, Melanie; Berke, Allison P; Herlihy, Kara; Pick, Horst; Vogel, Horst; Zhang, Shuguang

2009-07-21

Although understanding of the olfactory system has progressed at the level of downstream receptor signaling and the wiring of olfactory neurons, the system remains poorly understood at the molecular level of the receptors and their interaction with and recognition of odorant ligands. The structure and functional mechanisms of these receptors still remain a tantalizing enigma, because numerous previous attempts at the large-scale production of functional olfactory receptors (ORs) have not been successful to date. To investigate the elusive biochemistry and molecular mechanisms of olfaction, we have developed a mammalian expression system for the large-scale production and purification of a functional OR protein in milligram quantities. Here, we report the study of human OR17-4 (hOR17-4) purified from a HEK293S tetracycline-inducible system. Scale-up of production yield was achieved through suspension culture in a bioreactor, which enabled the preparation of >10 mg of monomeric hOR17-4 receptor after immunoaffinity and size exclusion chromatography, with expression yields reaching 3 mg/L of culture medium. Several key post-translational modifications were identified using MS, and CD spectroscopy showed the receptor to be approximately 50% alpha-helix, similar to other recently determined G protein-coupled receptor structures. Detergent-solubilized hOR17-4 specifically bound its known activating odorants lilial and floralozone in vitro, as measured by surface plasmon resonance. The hOR17-4 also recognized specific odorants in heterologous cells as determined by calcium ion mobilization. Our system is feasible for the production of large quantities of OR necessary for structural and functional analyses and research into OR biosensor devices.

History dependence in insect flight decisions during odor tracking.

PubMed

Pang, Rich; van Breugel, Floris; Dickinson, Michael; Riffell, Jeffrey A; Fairhall, Adrienne

2018-02-01

Natural decision-making often involves extended decision sequences in response to variable stimuli with complex structure. As an example, many animals follow odor plumes to locate food sources or mates, but turbulence breaks up the advected odor signal into intermittent filaments and puffs. This scenario provides an opportunity to ask how animals use sparse, instantaneous, and stochastic signal encounters to generate goal-oriented behavioral sequences. Here we examined the trajectories of flying fruit flies (Drosophila melanogaster) and mosquitoes (Aedes aegypti) navigating in controlled plumes of attractive odorants. While it is known that mean odor-triggered flight responses are dominated by upwind turns, individual responses are highly variable. We asked whether deviations from mean responses depended on specific features of odor encounters, and found that odor-triggered turns were slightly but significantly modulated by two features of odor encounters. First, encounters with higher concentrations triggered stronger upwind turns. Second, encounters occurring later in a sequence triggered weaker upwind turns. To contextualize the latter history dependence theoretically, we examined trajectories simulated from three normative tracking strategies. We found that neither a purely reactive strategy nor a strategy in which the tracker learned the plume centerline over time captured the observed history dependence. In contrast, "infotaxis", in which flight decisions maximized expected information gain about source location, exhibited a history dependence aligned in sign with the data, though much larger in magnitude. These findings suggest that while true plume tracking is dominated by a reactive odor response it might also involve a history-dependent modulation of responses consistent with the accumulation of information about a source over multi-encounter timescales. This suggests that short-term memory processes modulating decision sequences may play a role in natural plume tracking.

Using odor cues to elicit a behavioral and hormonal response in zoo-housed African wild dogs.

PubMed

Rafacz, Michelle L; Santymire, Rachel M

2014-01-01

Olfactory enrichment, like odor cues, can positively affect behavior, reproductive success, and stress physiology in zoo-housed species. Our goal was to determine if odor cues were enriching to the African wild dog (AWD; Lycaon pictus), a species with a complex social structure and a highly developed sense of smell. Our objectives were to: (1) examine changes in activity levels and stress hormone physiology in response to fecal odor cues from natural competitor and natural/unnatural prey species; and (2) determine whether these odor cues could function as effective enrichment for zoo-housed AWDs. Over a 6-month period, fecal samples were collected from two males (AWD 1: dominant, AWD 2: subordinate), fecal glucocorticoid metabolites (FGMs) were validated using an ACTH-challenge, and hormones were analyzed for FGMs by enzyme immunoassay. Behavioral observations were conducted using scan-sampling, and contact and proximity were recorded. AWDs were presented with three fecal odor cues: LION (competitor), CATTLE (unnatural prey), and GAZELLE (natural prey). Only the GAZELLE cue elicited an increase in activity (10.6%) in both individuals and increased positive social behaviors with higher frequencies of affiliative, submissive, and dominant behavior. AWD 1 demonstrated lower (P < 0.05) FGMs than AWD 2 both before and after all odor cues, and FGMs decreased (P = 0.08) in AWD 2 after all cues. We conclude that exposure to natural prey odor cues may be used as effective enrichment for AWDs, and that changes in stress hormone physiology in response to odor cues may be dependent on social rank in this species. © 2013 Wiley Periodicals, Inc.

History dependence in insect flight decisions during odor tracking

PubMed Central

van Breugel, Floris; Dickinson, Michael; Riffell, Jeffrey A.; Fairhall, Adrienne

2018-01-01

Natural decision-making often involves extended decision sequences in response to variable stimuli with complex structure. As an example, many animals follow odor plumes to locate food sources or mates, but turbulence breaks up the advected odor signal into intermittent filaments and puffs. This scenario provides an opportunity to ask how animals use sparse, instantaneous, and stochastic signal encounters to generate goal-oriented behavioral sequences. Here we examined the trajectories of flying fruit flies (Drosophila melanogaster) and mosquitoes (Aedes aegypti) navigating in controlled plumes of attractive odorants. While it is known that mean odor-triggered flight responses are dominated by upwind turns, individual responses are highly variable. We asked whether deviations from mean responses depended on specific features of odor encounters, and found that odor-triggered turns were slightly but significantly modulated by two features of odor encounters. First, encounters with higher concentrations triggered stronger upwind turns. Second, encounters occurring later in a sequence triggered weaker upwind turns. To contextualize the latter history dependence theoretically, we examined trajectories simulated from three normative tracking strategies. We found that neither a purely reactive strategy nor a strategy in which the tracker learned the plume centerline over time captured the observed history dependence. In contrast, “infotaxis”, in which flight decisions maximized expected information gain about source location, exhibited a history dependence aligned in sign with the data, though much larger in magnitude. These findings suggest that while true plume tracking is dominated by a reactive odor response it might also involve a history-dependent modulation of responses consistent with the accumulation of information about a source over multi-encounter timescales. This suggests that short-term memory processes modulating decision sequences may play a role in natural plume tracking. PMID:29432454

Smelling is Telling: Human Olfactory Cues Influence Social Judgments in Semi-Realistic Interactions.

PubMed

Gaby, Jessica M; Zayas, Vivian

2017-06-01

How does a person's smell affect others' impressions of them? Most body odor research asks perceivers to make social judgments based on armpit sweat without perfume or deodorant, presented on t-shirts. Yet, in real life, perceivers encounter fragranced body odor, on whole bodies. Our "raters" wore blindfolds and earplugs and repeatedly smelled same-sex "donors" in live interactions. In one condition, donors wore their normal deodorant and perfume ("diplomatic" odor) while in the other condition, donors were asked to avoid all outside fragrance influences ("natural" odor). We assessed the reliability of social judgments based on such live interactions, and the relationships between live judgments and traditional t-shirt based judgments, and between natural- and diplomatic odor-based judgments. Raters' repeated live social judgments (e.g., friendliness, likeability) were highly consistent for both diplomatic and natural odor, and converged with judgments based on t-shirts. However, social judgments based on natural odor did not consistently predict social judgments based on diplomatic odor, suggesting that natural and diplomatic body odor may convey different types of social information. Our results provide evidence that individuals can perceive reliable, meaningful social olfactory signals from whole bodies, at social distances, regardless of the presence or absence of perfume. Importantly, however, the social value of these signals is modified by the addition of exogenous fragrances. Further, our focus on judgments in same-sex dyads suggests that these olfactory cues hold social value in non-mating contexts. We suggest that future research employ more ecologically relevant methods. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Modeling of Spatial and Temporal Dynamics in Biological Olfactory Systems

DTIC Science & Technology

2007-09-21

odorants were anisole, camphor , isoamyle acetate, and ilmonene, denoted by ANI, CAM, ISO, and LIM, respectively. The curve fitting resulted in the...much less dimensional connections to the mitral The investigated odorants were anisole (ANI), camphor (CAM), cells. The glomeruli are also highly

Research on odor interaction between aldehyde compounds via a partial differential equation (PDE) model.

PubMed

Yan, Luchun; Liu, Jiemin; Qu, Chen; Gu, Xingye; Zhao, Xia

2015-01-28

In order to explore the odor interaction of binary odor mixtures, a series of odor intensity evaluation tests were performed using both individual components and binary mixtures of aldehydes. Based on the linear relation between the logarithm of odor activity value and odor intensity of individual substances, the relationship between concentrations of individual constituents and their joint odor intensity was investigated by employing a partial differential equation (PDE) model. The obtained results showed that the binary odor interaction was mainly influenced by the mixing ratio of two constituents, but not the concentration level of an odor sample. Besides, an extended PDE model was also proposed on the basis of the above experiments. Through a series of odor intensity matching tests for several different binary odor mixtures, the extended PDE model was proved effective at odor intensity prediction. Furthermore, odorants of the same chemical group and similar odor type exhibited similar characteristics in the binary odor interaction. The overall results suggested that the PDE model is a more interpretable way of demonstrating the odor interactions of binary odor mixtures.

The use of dispersion modeling to determine the feasibility of vegetative environmental buffers (VEBS) at controlling odor dispersion

NASA Astrophysics Data System (ADS)

Weber, Eric E.

Concentrated animal feeding operations (CAFOs) have been experiencing increased resistance from surrounding residents making construction of new facilities or expansion of existing ones increasingly limited (Jacobson et al., 2002). Such concerns often include the impact of nuisance odor on peoples’ lives and on the environment (Huang and Miller, 2006). Vegetative environmental buffers (VEBs) have been suggested as a possible odor control technology. They have been found to impact odor plume dispersion and have shown the possibility of being an effective tool for odor abatement when used alone or in combination with other technologies (Lin et al., 2006). The main objective of this study was to use Gaussian-type dispersion modeling to determine the feasibility of use and the effectiveness of a VEB at controlling the spread of odor from a swine feeding operation. First, wind tunnel NH3 dispersion trends were compared to model generated dispersion trends to determine the accuracy of the model at handling VEB dispersion. Next, facility-scale (northern Missouri specific) model simulations with and without a VEB were run to determine its viability as an option for dispersion reduction. Finally, dispersion forecasts that integrated numerical weather forecasts were developed and compared to collected concentration data to determine forecast accuracy. The results of this study found that dispersion models can be used to simulate dispersion around a VEB. AERMOD-generated dispersion trends were found to follow similar patterns of decreasing downwind concentration to those of both wind tunnel simulations and previous research. This shows that a VEB can be incorporated into AERMOD and that the model can be used to determine its effectiveness as an odor control option. The results of this study also showed that a VEB has an effect on odor dispersion by reducing downwind concentrations. This was confirmed by both wind tunnel and AERMOD simulations of dispersion displaying decreased downwind concentrations from a control scenario. This shows that VEBs have the potential to act as an odor control option for CAFOs. This study also found that a forecast method that integrated numerical weather prediction into dispersion models could be developed to forecast areas of high concentration. Model-forecasted dispersion trends had a high spatial correlation with collected concentrations for days when the facility was emitting. This shows that dispersion models can accurately predict high concentration areas using forecasted weather data. The information provided by this study may ultimately prove useful for this particular facility and others and may help to lower tensions with surrounding residents.

Simple circular odor chart for characterization of trace amounts of odorants discharged from thirteen odor sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoshika, Y.; Nihei, Y.; Muto, G.

1981-04-01

A simple circular odor chart is proposed for the explanation of the relationship between sensory responses (to odor quality and intensity) to odors and chemical analysis data of the odorants responsible for each odor discharged from thirteen odor sources. The odorants were classified into eight odorant groups and were analyzed by a systematic gas chromatographic (GC) technique. The characterization of the trace amounts of the odorants was carried out by using the values of a new proposed unit (pOU) based on the ratio of detected concentration to recognition threshold value. The calculated pOU values of the eight groups were plottedmore » in circular charts. It was found that the shape and size of each circular odor chart represent the quality and the intensity of each odor.« less

Odors: appetizing or satiating? Development of appetite during odor exposure over time.

PubMed

Ramaekers, M G; Boesveldt, S; Lakemond, C M M; van Boekel, M A J S; Luning, P A

2014-05-01

Exposure to palatable food odors influences appetite responses, either promoting or inhibiting food intake. Possibly, food odors are appetizing after a short exposure (of circa 1-3 min), but become satiating over time (circa 10-20 min). To investigate the effect of odor exposure on general appetite and sensory-specific appetite (SSA) over time. In a cross-over study, 21 unrestrained women (age: 18-45 years; BMI: 18.5-25 kg m(-2)) were exposed for 20 min to eight different odor types: five food odors, two nonfood odors and no-odor. All odors were distributed in a test room at suprathreshold levels. General appetite, SSA and salivation were measured over time. All food odors significantly increased general appetite and SSA, compared with the no-odor condition. The nonfood odors decreased general appetite. All effects did not change over time during odor exposure. Savory odors increased the appetite for savory foods, but decreased appetite for sweet foods, and vice versa after exposure to sweet odors. Neither food odors nor nonfood odors affected salivation. Palatable food odors were appetizing during and after odor exposure and did not become satiating over a 20-min period. Food odors had a large impact on SSA and a small impact on general appetite. Moreover, exposure to food odors increased the appetite for congruent foods, but decreased the appetite for incongruent foods. It may be hypothesized that, once the body is prepared for intake of a certain food with a particular macronutrient composition, it is unfavorable to consume foods that are very different from the cued food.

Intranasal Localizability of Odorants: Influence of Stimulus Volume

PubMed Central

Frasnelli, J.; Berg, J.; Huang, G.; Doty, R.L.

2011-01-01

When an odorant is presented to one side of the nose and air to the other, the ability to localize which side received the odorant depends upon trigeminal nerve stimulation. It has been shown that performance on this lateralization task increases as stimulus concentration increases. In this study, we determined the influences of stimulus volume and sex on the ability to localize each of 8 odorants presented at neat concentrations: anethole, geraniol, limonene, linalool, menthol, methyl salicyclate, phenyl ethanol, and vanillin. At a low stimulus volume (11 mL), only menthol was localized at an above-chance level. At a high stimulus volume (21 mL), above-chance localization occurred for all odorants except vanillin. Women were significantly better than men in localizing menthol. Stimuli rated as most intense were those that were most readily localized. The detection performance measures, as well as rated intensity values, significantly correlated with earlier findings of the trigeminal detectability of odorants presented to anosmic and normosmic subjects. This study suggests that differences in stimulus volume may explain some discrepant findings within the trigeminal chemosensory literature and supports the concept that vanillin may be a “relatively pure” olfactory stimulus. PMID:21310764

Intranasal localizability of odorants: influence of stimulus volume.

PubMed

Frasnelli, J; Hummel, T; Berg, J; Huang, G; Doty, R L

2011-05-01

When an odorant is presented to one side of the nose and air to the other, the ability to localize which side received the odorant depends upon trigeminal nerve stimulation. It has been shown that performance on this lateralization task increases as stimulus concentration increases. In this study, we determined the influences of stimulus volume and sex on the ability to localize each of 8 odorants presented at neat concentrations: anethole, geraniol, limonene, linalool, menthol, methyl salicylate, phenyl ethanol, and vanillin. At a low stimulus volume (11 mL), only menthol was localized at an above-chance level. At a high stimulus volume (21 mL), above-chance localization occurred for all odorants except vanillin. Women were significantly better than men in localizing menthol. Stimuli rated as most intense were those that were most readily localized. The detection performance measures, as well as rated intensity values, significantly correlated with earlier findings of the trigeminal detectability of odorants presented to anosmic and normosmic subjects. This study suggests that differences in stimulus volume may explain some discrepant findings within the trigeminal chemosensory literature and supports the concept that vanillin may be a "relatively pure" olfactory stimulus.

Identification of Hydrogen Disulfanes and Hydrogen Trisulfanes in H2S Bottle, in Flint, and in Dry Mineral White Wine.

PubMed

Starkenmann, Christian; Chappuis, Charles Jean-Francois; Niclass, Yvan; Deneulin, Pascale

2016-11-30

Through the accidental contamination of a gas cylinder of H 2 S, the importance of polysulfanes for flint, gun powder, and match odors was discovered. The hydrogen disulfane was prepared from disulfanediylbis[methyl(diphenyl)silane], and its odor descriptor was evaluated in the gas phase from a gas chromatograph coupled to an olfaction port. The occurrence of this compound in flint and pebbles was confirmed by analyses after derivatization with pentafluorobromobenzene. The occurrence of this sulfane was also confirmed in two dry white Swiss Chasselas wines, sorted by a large-scale sensory analysis from 80 bottles and evaluated by 62 wine professionals. The occurrence of disulfane was confirmed for the two wines described as the most mineral. Polysulfane comprises a class of compounds contributing to the flint odor and that may contribute to the wine mineral odor descriptor. Due to the high volatility and instability pure HSSH was not isolated but kept in solution and its odor profile was described by gas chromatography coupled to an olfaction port as flint, matches, and fireworks with a higher odor intensity compared to H 2 S.

Neuroendocrine changes upon exposure to predator odors.

PubMed

Hegab, Ibrahim M; Wei, Wanhong

2014-05-28

Predator odors are non-intrusive and naturalistic stressors of high ethological relevance in animals. Upon exposure to a predator or its associated cues, robust physiological and molecular anti-predator defensive strategies are elicited thereby allowing prey species to recognize, avoid and defend against a possible predation threat. In this review, we will discuss the nature of neuroendocrine stress responses upon exposure to predator odors. Predator odors can have a profound effect on the endocrine system, including activation of the hypothalamic-pituitary-adrenal axis, and induction of stress hormones such as corticosterone and adrenocorticotropic hormone. On a neural level, short-term exposure to predator odors leads to induction of the c-fos gene, while induction of ΔFosB in a different brain region is detected under chronic predation stress. Future research should aim to elucidate the relationships between neuroendocrine and behavioral outputs to gage the different levels of anti-predator responses in prey species. Copyright © 2014 Elsevier Inc. All rights reserved.

Odor Impression Prediction from Mass Spectra.

PubMed

Nozaki, Yuji; Nakamoto, Takamichi

2016-01-01

The sense of smell arises from the perception of odors from chemicals. However, the relationship between the impression of odor and the numerous physicochemical parameters has yet to be understood owing to its complexity. As such, there is no established general method for predicting the impression of odor of a chemical only from its physicochemical properties. In this study, we designed a novel predictive model based on an artificial neural network with a deep structure for predicting odor impression utilizing the mass spectra of chemicals, and we conducted a series of computational analyses to evaluate its performance. Feature vectors extracted from the original high-dimensional space using two autoencoders equipped with both input and output layers in the model are used to build a mapping function from the feature space of mass spectra to the feature space of sensory data. The results of predictions obtained by the proposed new method have notable accuracy (R≅0.76) in comparison with a conventional method (R≅0.61).

Olfactory receptor neurons use gain control and complementary kinetics to encode intermittent odorant stimuli

PubMed Central

Gorur-Shandilya, Srinivas; Demir, Mahmut; Long, Junjiajia; Clark, Damon A; Emonet, Thierry

2017-01-01

Insects find food and mates by navigating odorant plumes that can be highly intermittent, with intensities and durations that vary rapidly over orders of magnitude. Much is known about olfactory responses to pulses and steps, but it remains unclear how olfactory receptor neurons (ORNs) detect the intensity and timing of natural stimuli, where the absence of scale in the signal makes detection a formidable olfactory task. By stimulating Drosophila ORNs in vivo with naturalistic and Gaussian stimuli, we show that ORNs adapt to stimulus mean and variance, and that adaptation and saturation contribute to naturalistic sensing. Mean-dependent gain control followed the Weber-Fechner relation and occurred primarily at odor transduction, while variance-dependent gain control occurred at both transduction and spiking. Transduction and spike generation possessed complementary kinetic properties, that together preserved the timing of odorant encounters in ORN spiking, regardless of intensity. Such scale-invariance could be critical during odor plume navigation. DOI: http://dx.doi.org/10.7554/eLife.27670.001 PMID:28653907

Assessment of predation risk through conspecific alarm odors by spiny lobsters: How much is too much?

PubMed

Briones-Fourzán, Patricia

2009-07-01

Strong "alarm odors" emanating from lethally injured conspecifics may indicate an imminent risk of predation to spiny lobsters. In laboratory trials,1 strong conspecific alarm odors elicited avoidance in Panulirus argus, a highly gregarious species that displays collective defense behavior, but not in Panulirus guttatus, a species that tends to aggregate when reproductive activity is high (spring) but not when it is low (late summer) and does not display collective defensive behavior. To reduce predation risk, however, lobsters may autotomize limbs, thus sustaining nonlethal injuries. I tested the response of these lobsters to scents emanating from intact, lethally-injured and non-lethally injured conspecifics. In P. argus, these scents elicited, respectively, attraction, avoidance and a random response, suggesting that, in P. argus, avoidance of conspecific alarm odors depends on their strength. In contrast, P. guttatus lobsters responded at random to scents of lethally injured conspecifics and showed a similar response to scents of intact and non-lethally injured conspecifics in the spring (attraction) and in the summer (random), reflecting the more cryptic defensive behavior of this species. Therefore, both species use conspecific alarm odors for risk-assessment, but each responds to these cues in the most effective way to reduce its risk of predation.

Odor-color associations differ with verbal descriptors for odors: A comparison of three linguistically diverse groups.

PubMed

de Valk, Josje M; Wnuk, Ewelina; Huisman, John L A; Majid, Asifa

2017-08-01

People appear to have systematic associations between odors and colors. Previous research has emphasized the perceptual nature of these associations, but little attention has been paid to what role language might play. It is possible odor-color associations arise through a process of labeling; that is, participants select a descriptor for an odor and then choose a color accordingly (e.g., banana odor → "banana" label → yellow). If correct, this would predict odor-color associations would differ as odor descriptions differ. We compared speakers of Dutch (who overwhelmingly describe odors by referring to the source; e.g., smells like banana) with speakers of Maniq and Thai (who also describe odors with dedicated, abstract smell vocabulary; e.g., musty), and tested whether the type of descriptor mattered for odor-color associations. Participants were asked to select a color that they associated with an odor on two separate occasions (to test for consistency), and finally to label the odors. We found the hunter-gatherer Maniq showed few, if any, consistent or accurate odor-color associations. More importantly, we found the types of descriptors used to name the smells were related to the odor-color associations. When people used abstract smell terms to describe odors, they were less likely to choose a color match, but when they described an odor with a source-based term, their color choices more accurately reflected the odor source, particularly when the odor source was named correctly (e.g., banana odor → yellow). This suggests language is an important factor in odor-color cross-modal associations.

Discrimination of Swiss cheese from 5 different factories by high impact volatile organic compound profiles determined by odor activity value using selected ion flow tube mass spectrometry and odor threshold.

PubMed

Taylor, Kaitlyn; Wick, Cheryl; Castada, Hardy; Kent, Kyle; Harper, W James

2013-10-01

Swiss cheese contains more than 200 volatile organic compounds (VOCs). Gas chromatography-mass spectrometry has been utilized for the analysis of volatile compounds in food products; however, it is not sensitive enough to measure VOCs directly in the headspace of a food at low concentrations. Selected ion flow tube mass spectrometry (SIFT-MS) provides a basis for determining the concentrations of VOCs in the head space of the sample in real time at low concentration levels of parts per billion/trillion by volume. Of the Swiss cheese VOCs, relatively few have a major impact on flavor quality. VOCs with odor activity values (OAVs) (concentration/odor threshold) greater than one are considered high-impact flavor compounds. The objective of this study was to utilize SIFT-MS concentrations in conjunction with odor threshold values to determine OAVs thereby identifying high-impact VOCs to use for differentiating Swiss cheese from five factories and identify the factory variability. Seventeen high-impact VOCs were identified for Swiss cheese based on an OAV greater than one in at least 1 of the 5 Swiss cheese factories. Of these, 2,3-butanedione was the only compound with significantly different OAVs in all factories; however, cheese from any pair of factories had multiple statistically different compounds based on OAV. Principal component analysis using soft independent modeling of class analogy statistical differentiation plots, with all of the OAVs, showed differentiation between the 5 factories. Overall, Swiss cheese from different factories was determined to have different OAV profiles utilizing SIFT-MS to determine OAVs of high impact compounds. © 2013 Institute of Food Technologists®

Quality improvement by batch vacuum distillation and physicochemical characterization of clove leaf oil in Central Java, Indonesia

NASA Astrophysics Data System (ADS)

Alighiri, D.; Eden, W. T.; Cahyono, E.; Supardi, K. I.

2018-03-01

Clove leaf oil is one of the essential oils which have high economic value and produced in considerable amount in Indonesia. As many as 60% of clove oil produced by Indonesia has exported to many countries in the world. Musuk and Ringinlarik Village, Boyolali District, Central Java Province is one of the areas in Indonesia which became the primary supplier of Indonesian clove leaf oil. Although, the quality of the resulting yield is still low because it uses a simple distillation kettle in the form of the iron plate or used the drum. The clove leaf oil produced by steam distillation from the dry whole leaves of the clove tree. The color of the oil is brownish black and dirty with the odor are fresh distilled, spicy, warm, and terpenic. The specific gravity at 25 °C of 1.529, the refractive index at 20 °C of 1.030, and based on GC-MS analysis, eugenol levels only 68% and caryophyllene is too high, i.e., 20%. The quality of clove leaf oil produced does not meet the specifications of international market standards. This work aimed to improve the quality of Indonesian clove leaf oil. The purifications done in this research was used by batch vacuum distillation with mode operation at vacuum -76 cmHg and reflux ratios 5:1. Clove leaf oil produced by using this method has a better physicochemical characterization, i.e., the appearance that is yellow to pale color with the odor is spicy, woody, warm, and terpenic. The specific gravity at 25 °C of 1.533, the refractive index at 20 °C of 1.038, and eugenol and caryophyllene contents has yielded 80.58% and 10%, respectively. By The enhancement quality of clove leaf oil by batch vacuum distillation, these oil is already meet international standards and income of clove leaf oil grower in Musuk and Ringinlarik Village, Boyolali District, Central Java Province, Indonesia could be increased.

Removal of odor using biofilter from duck confinement buildings.

PubMed

Lau, Anthony; Cheng, Kimberly

2007-06-01

The poultry and waterfowl industry in the Fraser Valley of British Columbia needs to deal with odor emission problems. The objective of this study is to evaluate the performance of a pilot-scale biofiltration system for treating odors from the exhaust air streams of a commercial duck farm building before their release to the atmosphere. A pilot-scale biofiltration system with semi-enclosed wooden structure was designed, constructed and installed to treat the exhaust air from one of the 12 operating ventilation exhaust fans, having a ventilation rate of 2.36 m3/s. The empty bed residence time of the biofilter was 5-10 seconds at the design flow rate. The biofilter media comprised of 2 parts softwood chips and barks to 1 part finished compost. Fabric filters were used for pre-treatment to protect the biofilter from clogging by dust particles and feathers. Odor reduction was determined by measuring the concentration of the air entering and leaving the biofilter via olfactometry analysis. The odor concentration of untreated barn air was found to vary from 8553+/-1006 to 12171+/-1575 OU/m3; however, the odor concentration was substantially reduced to 420+/-195 OU/m(3) after the manure storage was cleaned out at the end of summer. The odor removal efficiency of the biofilter system averaged 95+/-3%. The high frequency of cleaning and replacement required of the fabric filters would considerably increase the operating cost. Alternative methods of dust and odor removal that are more cost-effective will need to be investigated in the future.

The differential mice response to cat and snake odor.

PubMed

de Oliveira Crisanto, Karen; de Andrade, Wylqui Mikael Gomes; de Azevedo Silva, Kayo Diogenes; Lima, Ramón Hypolito; de Oliveira Costa, Miriam Stela Maris; de Souza Cavalcante, Jeferson; de Lima, Ruthnaldo Rodrigues Melo; do Nascimento, Expedito Silva; Cavalcante, Judney Cley

2015-12-01

Studies from the last two decades have pointed to multiple mechanisms of fear. For responding to predators, there is a group of highly interconnected hypothalamic nuclei formed by the anterior hypothalamic nucleus, the ventromedial hypothalamic nucleus and the dorsal premammillary nucleus—the predator-responsive hypothalamic circuit. This circuit expresses Fos in response to predator presence or its odor. Lesion of any component of this system blocks or reduces the expression of fear and consequently defensive behavior when faced with a predator or its cue. However, most of the knowledge about that circuit has been obtained using the rat as a model of prey and the cat as a source of predator cues. In the present study, we exposed mice to strong cat or snake odors, two known mice predators, and then we used the rat exposure test (RET) to study their behavior when confronted with the same predator's odor. Our data point to a differential response of mice exposed to these odors. When Swiss mice were exposed to the cat odor, they show defensive behavior and the predator-responsive hypothalamic circuit expressed Fos. The opposite was seen when they faced snake's odor. The acute odor exposure was not sufficient to activate the mouse predator-responsive hypothalamic circuit and the mice acted like they were not in a stressful situation, showing almost no sign of fear or defensive posture. This leads us to the conclusion that not all the predator cues are sufficient to activate the predator-responsive hypothalamic circuit of mice and that their response depends on the danger that these predators represent in the natural history of the prey.

An assessment of the liquid-gas partitioning behavior of major wastewater odorants using two comparative experimental approaches: liquid sample-based vaporization vs. impinger-based dynamic headspace extraction into sorbent tubes.

PubMed

Iqbal, Mohammad Asif; Kim, Ki-Hyun; Szulejko, Jan E; Cho, Jinwoo

2014-01-01

The gas-liquid partitioning behavior of major odorants (acetic acid, propionic acid, isobutyric acid, n-butyric acid, i-valeric acid, n-valeric acid, hexanoic acid, phenol, p-cresol, indole, skatole, and toluene (as a reference)) commonly found in microbially digested wastewaters was investigated by two experimental approaches. Firstly, a simple vaporization method was applied to measure the target odorants dissolved in liquid samples with the aid of sorbent tube/thermal desorption/gas chromatography/mass spectrometry. As an alternative method, an impinger-based dynamic headspace sampling method was also explored to measure the partitioning of target odorants between the gas and liquid phases with the same detection system. The relative extraction efficiency (in percent) of the odorants by dynamic headspace sampling was estimated against the calibration results derived by the vaporization method. Finally, the concentrations of the major odorants in real digested wastewater samples were also analyzed using both analytical approaches. Through a parallel application of the two experimental methods, we intended to develop an experimental approach to be able to assess the liquid-to-gas phase partitioning behavior of major odorants in a complex wastewater system. The relative sensitivity of the two methods expressed in terms of response factor ratios (RFvap/RFimp) of liquid standard calibration between vaporization and impinger-based calibrations varied widely from 981 (skatole) to 6,022 (acetic acid). Comparison of this relative sensitivity thus highlights the rather low extraction efficiency of the highly soluble and more acidic odorants from wastewater samples in dynamic headspace sampling.

Characterizing odors from cattle feedlots with different odor techniques

USDA-ARS?s Scientific Manuscript database

Odors from cattle feedlots negatively affect local communities. The purpose of this study was to characterize odors and odorants using different odor sampling techniques. Odors were characterized with field olfactometers (Nasal Ranger®), sensory techniques (GC-O) and analytical techniques (sorbent t...

Walking patterns induced by learned odors in the honeybee, Apis mellifera L.

PubMed

Yamashita, Toshiya; Haupt, S Shuichi; Ikeno, Hidetoshi; Ai, Hiroyuki

2016-01-01

The odor localization strategy induced by odors learned via differential conditioning of the proboscis extension response was investigated in honeybees. In response to reward-associated but not non-reward-associated odors, learners walked longer paths than non-learners and control bees. When orange odor reward association was learned, the path length and the body turn angles were small during odor stimulation and greatly increased after stimulation ceased. In response to orange odor, bees walked locally with alternate left and right turns during odor stimulation to search for the reward-associated odor source. After odor stimulation, bees walked long paths with large turn angles to explore the odor plume. For clove odor, learning-related modulations of locomotion were less pronounced, presumably due to a spontaneous preference for orange in the tested population of bees. This study is the first to describe how an odor-reward association modulates odor-induced walking in bees. © 2016. Published by The Company of Biologists Ltd.

Effects of vomeronasal organ removal on individual odor discrimination, sex-odor preference, and scent marking by female hamsters.

PubMed

Petrulis, A; Peng, M; Johnston, R E

1999-03-01

Removal of the vomeronasal organ (VNX) did not eliminate the ability of female hamsters to discriminate between individual male's flank gland or urine odors in a habituation/discrimination task nor did it impair preference for male odors over female odors from a distance. Vomeronasal organ removal did reduce overall levels of investigation of flank gland odor in the habituation/discrimination task. Although VNX females did not show severe impairments in the frequency of either flank or vaginal marking in response to odors, they did show an abnormal pattern of marking. VNX females, unlike shams, did not flank mark more to female odors than to male odors, nor did they vaginal mark more to male odors than to female odors. Thus, the vomeronasal organ in female hamsters appears to be important for differences in scent marking toward male and female odors, but is not essential for discrimination of individual odors or for preferences for male over female odors.

Characterization of the key aroma compounds in pink guava (Psidium guajava L.) by means of aroma re-engineering experiments and omission tests.

PubMed

Steinhaus, Martin; Sinuco, Diana; Polster, Johannes; Osorio, Coralia; Schieberle, Peter

2009-04-08

Seventeen aroma-active volatiles, previously identified with high flavor dilution factors in fresh, pink Colombian guavas (Psidium guajava L.), were quantified by stable isotope dilution assays. On the basis of the quantitative data and odor thresholds in water, odor activity values (OAV; ratio of concentration to odor threshold) were calculated. High OAVs were determined for the green, grassy smelling (Z)-3-hexenal and the grapefruit-like smelling 3-sulfanyl-1-hexanol followed by 3-sulfanylhexyl acetate (black currant-like), hexanal (green, grassy), ethyl butanoate (fruity), acetaldehyde (fresh, pungent), trans-4,5-epoxy-(E)-2-decenal (metallic), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel, sweet), cinnamyl alcohol (floral), methyl (2S,3S)-2-hydroxy-3-methylpentanoate (fruity), cinnamyl acetate (floral), methional (cooked potato-like), and 3-hydroxy-4,5-dimethyl-2(5H)-furanone (seasoning-like). Studies on the time course of odorant formation in guava puree or cubes, respectively, showed that (Z)-3-hexenal was hardly present in the intact fruits, but was formed very quickly during crushing. The aroma of fresh guava fruit cubes, which showed a very balanced aroma profile, was successfully mimicked in a reconstitute consisting of 13 odorants in their naturally occurring concentrations. Omission tests, in which single odorants were omitted from the entire aroma reconstitute, revealed (Z)-3-hexenal, 3-sulfanyl-1-hexanol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-sulfanylhexyl acetate, hexanal, ethyl butanoate, cinnamyl acetate, and methional as the key aroma compounds of pink guavas.

The influence of oscillating dietary protein concentrations on finishing cattle. I. Feedlot performance and odorous compound production.

PubMed

Archibeque, S L; Miller, D N; Freetly, H C; Berry, E D; Ferrell, C L

2007-06-01

We hypothesized that oscillation of the dietary CP concentration, which may improve N retention of finishing beef steers, would reduce production of manure odor compounds and total N inputs while yielding comparable performance. Charolais-sired steers (n = 144; 303 +/- 5 kg of initial BW) were used in a completely randomized block design (6 pens/treatment). The steers were fed to 567 kg of BW on the following finishing diets, which were based on dry-rolled corn: 1) low (9.1% CP), 2) medium (11.8% CP), 3) high (14.9% CP), or 4) low and high oscillated on a 48-h interval for each feed (oscillating). Steers fed low tended (P = 0.08) to have less DMI (7.80 kg/d) than steers fed medium (8.60 kg/d) or oscillating (8.67 kg/d), but not less than steers fed high (8.12 kg/d). Daily N intake was greatest (P < 0.01) for steers fed high (189 g), intermediate for medium (160 g) and oscillating (164 g), and least for low (113 g). The ADG was lower (P < 0.01) for steers fed low (1.03 kg) than for those fed medium (1.45 kg), high (1.45 kg), or oscillating (1.43 kg). Similarly, steers fed low had a lower adjusted fat thickness (P < 0.01) and yield grade (P = 0.05) and tended (P = 0.10) to have less marbling than steers fed the other 3 diets. In slurries with feces, urine, soil, and water, incubated for 35 d, nonsoluble CP was similar among slurries from steers fed medium, high, or oscillating, but was less (P < 0.01) in slurries from steers fed low. However, throughout the incubation period, slurries from steers fed high or oscillating had greater (P < 0.01) concentrations of total aromatics and ammonia than those from steers fed low or medium. Also, the slurries from steers fed oscillating had greater (P < 0.01) concentrations of branched-chain VFA than manure slurries from steers fed any of the other diets. These data indicate that although there is no apparent alteration in the performance of finishing steers fed diets with oscillation of the dietary protein, there may be undesirable increases in the production of compounds associated with malodor.

Olfactory discrimination largely persists in mice with defects in odorant receptor expression and axon guidance

PubMed Central

2012-01-01

Background The defining feature of the main olfactory system in mice is that each olfactory sensory neuron expresses only one of more than a thousand different odorant receptor genes. Axons expressing the same odorant receptor converge onto a small number of targets in the olfactory bulb such that each glomerulus is made up of axon terminals expressing just one odorant receptor. It is thought that this precision in axon targeting is required to maintain highly refined odor discrimination. We previously showed that β3GnT2−/− mice have severe developmental and axon guidance defects. The phenotype of these mice is similar to adenylyl cyclase 3 (AC3) knockout mice largely due to the significant down-regulation of AC3 activity in β3GnT2−/− neurons. Results Microarray analysis reveals that nearly one quarter of all odorant receptor genes are down regulated in β3GnT2−/− mice compared to controls. Analysis of OR expression by quantitative PCR and in situ hybridization demonstrates that the number of neurons expressing some odorant receptors, such as mOR256-17, is increased by nearly 60% whereas for others such as mOR28 the number of neurons is decreased by more than 75% in β3GnT2−/− olfactory epithelia. Analysis of axon trajectories confirms that many axons track to inappropriate targets in β3GnT2−/− mice, and some glomeruli are populated by axons expressing more than one odorant receptor. Results show that mutant mice perform nearly as well as control mice in an odor discrimination task. In addition, in situ hybridization studies indicate that the expression of several activity dependent genes is unaffected in β3GnT2−/− olfactory neurons. Conclusions Results presented here show that many odorant receptors are under-expressed in β3GnT2−/− mice and further demonstrate that additional axon subsets grow into inappropriate targets or minimally innervate glomeruli in the olfactory bulb. Odor evoked gene expression is unchanged and β3GnT2−/− mice exhibit a relatively small deficit in their ability to discriminate divergent odors. Results suggest that despite the fact that β3GnT2−/− mice have decreased AC3 activity, decreased expression of many ORs, and display many axon growth and guidance errors, odor-evoked activity in cilia of mutant olfactory neurons remains largely intact. PMID:22559903

Pleasant and Unpleasant Odors Influence Hedonic Evaluations of Human Faces: An Event-Related Potential Study.

PubMed

Cook, Stephanie; Fallon, Nicholas; Wright, Hazel; Thomas, Anna; Giesbrecht, Timo; Field, Matt; Stancak, Andrej

2015-01-01

Odors can alter hedonic evaluations of human faces, but the neural mechanisms of such effects are poorly understood. The present study aimed to analyze the neural underpinning of odor-induced changes in evaluations of human faces in an odor-priming paradigm, using event-related potentials (ERPs). Healthy, young participants (N = 20) rated neutral faces presented after a 3 s pulse of a pleasant odor (jasmine), unpleasant odor (methylmercaptan), or no-odor control (clean air). Neutral faces presented in the pleasant odor condition were rated more pleasant than the same faces presented in the no-odor control condition, which in turn were rated more pleasant than faces in the unpleasant odor condition. Analysis of face-related potentials revealed four clusters of electrodes significantly affected by odor condition at specific time points during long-latency epochs (600-950 ms). In the 620-640 ms interval, two scalp-time clusters showed greater negative potential in the right parietal electrodes in response to faces in the pleasant odor condition, compared to those in the no-odor and unpleasant odor conditions. At 926 ms, face-related potentials showed greater positivity in response to faces in the pleasant and unpleasant odor conditions at the left and right lateral frontal-temporal electrodes, respectively. Our data shows that odor-induced shifts in evaluations of faces were associated with amplitude changes in the late (>600) and ultra-late (>900 ms) latency epochs. The observed amplitude changes during the ultra-late epoch are consistent with a left/right hemisphere bias towards pleasant/unpleasant odor effects. Odors alter evaluations of human faces, even when there is a temporal lag between presentation of odors and faces. Our results provide an initial understanding of the neural mechanisms underlying effects of odors on hedonic evaluations.

Pleasant and Unpleasant Odors Influence Hedonic Evaluations of Human Faces: An Event-Related Potential Study

PubMed Central

Cook, Stephanie; Fallon, Nicholas; Wright, Hazel; Thomas, Anna; Giesbrecht, Timo; Field, Matt; Stancak, Andrej

2015-01-01

Odors can alter hedonic evaluations of human faces, but the neural mechanisms of such effects are poorly understood. The present study aimed to analyze the neural underpinning of odor-induced changes in evaluations of human faces in an odor-priming paradigm, using event-related potentials (ERPs). Healthy, young participants (N = 20) rated neutral faces presented after a 3 s pulse of a pleasant odor (jasmine), unpleasant odor (methylmercaptan), or no-odor control (clean air). Neutral faces presented in the pleasant odor condition were rated more pleasant than the same faces presented in the no-odor control condition, which in turn were rated more pleasant than faces in the unpleasant odor condition. Analysis of face-related potentials revealed four clusters of electrodes significantly affected by odor condition at specific time points during long-latency epochs (600−950 ms). In the 620−640 ms interval, two scalp-time clusters showed greater negative potential in the right parietal electrodes in response to faces in the pleasant odor condition, compared to those in the no-odor and unpleasant odor conditions. At 926 ms, face-related potentials showed greater positivity in response to faces in the pleasant and unpleasant odor conditions at the left and right lateral frontal-temporal electrodes, respectively. Our data shows that odor-induced shifts in evaluations of faces were associated with amplitude changes in the late (>600) and ultra-late (>900 ms) latency epochs. The observed amplitude changes during the ultra-late epoch are consistent with a left/right hemisphere bias towards pleasant/unpleasant odor effects. Odors alter evaluations of human faces, even when there is a temporal lag between presentation of odors and faces. Our results provide an initial understanding of the neural mechanisms underlying effects of odors on hedonic evaluations. PMID:26733843

Effect of short chain inulin on the rheological and sensory characteristics of reduced fat set coconut milk yoghurt.

PubMed

Adegoke, Samuel Chetachukwu; Thongraung, Chakree; Yupanqui, Chutha Takahashi

2018-06-23

The effect of short-chain inulin on the rheological and sensory properties of reduced fat set coconut milk yoghurt was studied with whole fat coconut milk yoghurt as reference. The concentration of short-chain inulin was varied at 0, 5, 10, 15, and 20% w/v respectively. All the yoghurt samples displayed higher elastic modulus G' than viscous modulus G". However, 15% inulin yoghurt had the highest value for G' & G". The 15 and 20% inulin yoghurts displayed high yield stress (1036.7 ± 2.39 & 368.23 ± 0.30 Pa). Addition threshold of 15% was established, beyond this level there was a significant decrease in the yield stress, firmness, cohesiveness and consistency values of the reduced fat yoghurts. Using Pearson correlation analysis, no correlation was observed between firmness and yield stress, Similarly, there was significant correlation between the yield stress and instrumental viscosity r = 0.957; p < 0.01. Furthermore, all yoghurt samples displayed strain thinning behavior except whole fat yoghurt. Carbohydrate was affected by inulin incorporation. Addition of short chain inulin improved sensorial characteristics such as taste, and flavor, but did not display significant difference in color and odor of yoghurt samples. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

What's that smell? An ecological approach to understanding preferences for familiar odors.

PubMed

Schloss, Karen B; Goldberger, Carolyn S; Palmer, Stephen E; Levitan, Carmel A

2015-01-01

How do odor preferences arise? Following Palmer and Schloss's (2010, PNAS, 107, 8877-8882) ecological valence theory of color preferences, we propose that preference for an odor is determined by preferences for all objects and/or entities associated with that odor. The present results showed that preferences for familiar odors were strongly predicted by average preferences for all things associated with the odors (eg people liked the apple odor which was associated with mostly positive things, such as apples, soap, and candy, but disliked the fish odor, which was associated with mostly negative things, such as dead fish, trash, and vomit). The odor WAVEs (weighted affective valence estimates) performed significantly better than one based on preference for only the namesake object (eg predicting preference for the apple odor based on preference for apples). These results suggest that preferences for familiar odors are based on a summary statistic, coding the valence of previous odor-related experiences. We discuss how this account of odor preferences is consistent with the idea that odor preferences exist to guide organisms to approach beneficial objects and situations and avoid harmful ones.

Comparison of Breastmilk Odor and Vanilla Odor on Mitigating Premature Infants' Response to Pain During and After Venipuncture.

PubMed

Jebreili, Mahnaz; Neshat, Hanieh; Seyyedrasouli, Aleheh; Ghojazade, Morteza; Hosseini, Mohammad Bagher; Hamishehkar, Hamed

2015-09-01

The main purpose of this study was to investigate the calming effects of breastmilk odor and vanilla odor on preterm infants during and after venipuncture. One hundred thirty-five preterm infants were randomly selected and divided into three groups: control, vanilla odor, and breastmilk odor. Infants in the breastmilk group were exposed to breastmilk odor, and infants in the vanilla group were exposed to vanilla odor from 5 minutes before the start of sampling until 30 seconds after sampling. The Premature Infant Pain Profile was used for calculating quality of pain in infants during and after sampling. Statistical analyses showed that both vanilla and breastmilk odors had calming effects on premature infants during sampling, but just breastmilk odor had calming effects on infants after the end of sampling. Compared with vanilla odor, breastmilk odor has more calming effects on premature infants. Breastmilk odor can be used for calming premature infants during and after venipuncture.

Honey bee (Hymenoptera: Apidae) foraging in response to preconditioning with onion flower scent compounds.

PubMed

Silva, Erin M; Dean, Bill B; Hiller, Larry K

2003-10-01

Onion (Allium cepa L.) seed production has long been plagued with yield problems because of lack of pollination by the honey bee, Apis mellifera L. To attempt to attract more pollinators to the onion seed production field, honey bees were conditioned to associate onion floral odor components with a reward. Isolated nucleus hives of honey bees were fed 30% sucrose solutions scented with a 0.2% solution of onion floral odor compounds. After feeding on these solutions for 6 wk, bees were not found to prefer onion flowers to two competing food sources, carrot and alfalfa flowers, at the 5% significance level. However, there was an overall trend indicating a change in honey bee behavior, with fewer "trained" bees visiting alfalfa and carrot and more visiting onion. Thus, it may be possible to alter honey bee behavior with preconditioning but probably not to a degree that would be economically significant.

A "green process" for producing highly purified zein from commercial zein

USDA-ARS?s Scientific Manuscript database

Corn zein is the major protein component of ground corn, and co-products of the corn ethanol industry which includes corn gluten meal and distillers’ dried grains. Zein products generated from those co-products all possess yellow coloration and off-odor. Removal of yellow color and off-odor is essen...

The Regular Interaction Pattern among Odorants of the Same Type and Its Application in Odor Intensity Assessment.

PubMed

Yan, Luchun; Liu, Jiemin; Jiang, Shen; Wu, Chuandong; Gao, Kewei

2017-07-13

The olfactory evaluation function (e.g., odor intensity rating) of e-nose is always one of the most challenging issues in researches about odor pollution monitoring. But odor is normally produced by a set of stimuli, and odor interactions among constituents significantly influenced their mixture's odor intensity. This study investigated the odor interaction principle in odor mixtures of aldehydes and esters, respectively. Then, a modified vector model (MVM) was proposed and it successfully demonstrated the similarity of the odor interaction pattern among odorants of the same type. Based on the regular interaction pattern, unlike a determined empirical model only fit for a specific odor mixture in conventional approaches, the MVM distinctly simplified the odor intensity prediction of odor mixtures. Furthermore, the MVM also provided a way of directly converting constituents' chemical concentrations to their mixture's odor intensity. By combining the MVM with usual data-processing algorithm of e-nose, a new e-nose system was established for an odor intensity rating. Compared with instrumental analysis and human assessor, it exhibited accuracy well in both quantitative analysis (Pearson correlation coefficient was 0.999 for individual aldehydes ( n = 12), 0.996 for their binary mixtures ( n = 36) and 0.990 for their ternary mixtures ( n = 60)) and odor intensity assessment (Pearson correlation coefficient was 0.980 for individual aldehydes ( n = 15), 0.973 for their binary mixtures ( n = 24), and 0.888 for their ternary mixtures ( n = 25)). Thus, the observed regular interaction pattern is considered an important foundation for accelerating extensive application of olfactory evaluation in odor pollution monitoring.

Nested Expression Domains for Odorant Receptors in Zebrafish Olfactory Epithelium

NASA Astrophysics Data System (ADS)

Weth, Franco; Nadler, Walter; Korsching, Sigrun

1996-11-01

The mapping of high-dimensional olfactory stimuli onto the two-dimensional surface of the nasal sensory epithelium constitutes the first step in the neuronal encoding of olfactory input. We have used zebrafish as a model system to analyze the spatial distribution of odorant receptor molecules in the olfactory epithelium by quantitative in situ hybridization. To this end, we have cloned 10 very divergent zebrafish odorant receptor molecules by PCR. Individual genes are expressed in sparse olfactory receptor neurons. Analysis of the position of labeled cells in a simplified coordinate system revealed three concentric, albeit overlapping, expression domains for the four odorant receptors analyzed in detail. Such regionalized expression should result in a corresponding segregation of functional response properties. This might represent the first step of spatial encoding of olfactory input or be essential for the development of the olfactory system.

Characterization of odorants in inflatable aquatic toys and swimming learning devices-which substances are causative for the characteristic odor and potentially harmful?

PubMed

Wiedmer, Christoph; Velasco-Schön, Cristina; Buettner, Andrea

2017-06-01

Based on the observation of intense and offensive smells in the product group of aquatic toys, four representative products were exemplarily chosen and sensorially characterized by an expert panel. Panellists reported mostly almond- and rubber-like notes for three of the four samples, whereas the smell of the fourth sample was dominated by organic solvent-associated notes such as "nail polish-like." To elucidate the molecular reasons of these smells, we isolated the volatile fraction of the product by solvent extraction and high vacuum distillation, and identified the main odorants by aroma extract dilution analysis (AEDA), followed by one- and two-dimensional gas chromatography, with parallel mass spectrometric and olfactometric detection. Additionally, the materials of the samples were identified by means of differential scanning calorimetry (DSC), attenuated total reflectance spectroscopy (ATR-spectroscopy), and Beilstein halogen test. Between 32 and 46 odors could be detected in each sample by means of AEDA, whereby five to 13 of these compounds were detectable with by far the highest dilution factors, and were found to primarily correlate with the smells of the respective products. Focussing the subsequent identification on these causative substances led to the successful identification of the majority of these odorants. Among them were several mono- or di-unsaturated carbonyl compounds and their epoxidized derivatives, which are typical odorous artefacts from fatty acid oxidation, but also odor-active organic solvents such as cyclohexanone, isophorone, and phenol.

Association between major depressive disorder and odor identification impairment.

PubMed

Khil, Laura; Rahe, Corinna; Wellmann, Jürgen; Baune, Bernhard T; Wersching, Heike; Berger, Klaus

2016-10-01

There is evidence of olfactory deficits in patients with major depressive disorder (MDD) but causes and mechanisms are largely unknown. We compared 728 patients with current MDD and 555 non-depressed controls regarding odor identification impairment taking into account the severity of acute symptoms and of the disease course. We assessed current symptom severity with the Hamilton Depression Rating Scale, and disease course severity based on admission diagnosis (ICD-10, F32/F33) and self-reported hospitalization frequency, defined as infrequent (<2) and frequent (≥2) depression-related hospitalizations under constant disease duration. A score of <10 on the Sniffin' Sticks-Screen-12 test determined the presence of odor identification impairment. Compared to non-depressed controls patients with frequent (rapidly recurring) hospitalizations had an elevated chance of odor identification impairment, even after adjustment for smell-influencing factors, such as age and smoking, (OR=1.7; 95% CI 1.0-2.9). Patients with recurrent MDD (F33) also had an elevated odds of odor identification impairment compared to those with a first-time episode (F32, OR=1.5; 95% CI 1.0-2.4). In patients with a first-time episode the chance of odor identification impairment increased by 7% with each point increase in the Hamilton Score. Cross-sectional study. Variation in the use of psychotropic medication is a potential bias. Odor identification impairment was evident in MDD patients with first-time high symptom severity and in patients with a severe disease course. Whether odor identification impairment is a marker or mediator of structural and functional brain changes associated with acute or active MDD requires further investigations in longitudinal studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Food-related odor probes of brain reward circuits during hunger: a pilot FMRI study.

PubMed

Bragulat, Veronique; Dzemidzic, Mario; Bruno, Carolina; Cox, Cari A; Talavage, Thomas; Considine, Robert V; Kareken, David A

2010-08-01

Food aromas can be powerful appetitive cues in the natural environment. Although several studies have examined the cerebral responses to food images, none have used naturalistic food aromas to study obesity. Ten individuals (five normal-weight and five obese) were recruited to undergo 24 h of food deprivation. Subjects were then imaged on a 3T Siemens Trio-Tim scanner (Siemens, Erlangen, Germany) while smelling four food-related odors (FRO; two sweet odors and two fat-related) and four "nonappetitive odors" (NApO; e.g., Douglas fir). Before the imaging session, subjects rated their desire to eat each type of food to determine their most preferred (P-FRO). Across all 10 subjects, P-FRO elicited a greater blood oxygenation level dependent (BOLD) response than the NApO in limbic and reward-related areas, including the bilateral insula and opercular (gustatory) cortex, the anterior and posterior cingulate, and ventral striatum. Obese subjects showed greater activation in the bilateral hippocampus/parahippocampal gyrus, but lean controls showed more activation in the posterior insula. Brain areas activated by food odors are similar to those elicited by cues of addictive substances, such as alcohol. Food odors are highly naturalistic stimuli, and may be effective probes of reward-related networks in the context of hunger and obesity.

Development of an International Odor Identification Test for Children: The Universal Sniff Test.

PubMed

Schriever, Valentin A; Agosin, Eduardo; Altundag, Aytug; Avni, Hadas; Cao Van, Helene; Cornejo, Carlos; de Los Santos, Gonzalo; Fishman, Gad; Fragola, Claudio; Guarneros, Marco; Gupta, Neelima; Hudson, Robyn; Kamel, Reda; Knaapila, Antti; Konstantinidis, Iordanis; Landis, Basile N; Larsson, Maria; Lundström, Johan N; Macchi, Alberto; Mariño-Sánchez, Franklin; Martinec Nováková, Lenka; Mori, Eri; Mullol, Joaquim; Nord, Marie; Parma, Valentina; Philpott, Carl; Propst, Evan J; Rawan, Ahmed; Sandell, Mari; Sorokowska, Agnieszka; Sorokowski, Piotr; Sparing-Paschke, Lisa-Marie; Stetzler, Carolin; Valder, Claudia; Vodicka, Jan; Hummel, Thomas

2018-07-01

To assess olfactory function in children and to create and validate an odor identification test to diagnose olfactory dysfunction in children, which we called the Universal Sniff (U-Sniff) test. This is a multicenter study involving 19 countries. The U-Sniff test was developed in 3 phases including 1760 children age 5-7 years. Phase 1: identification of potentially recognizable odors; phase 2: selection of odorants for the odor identification test; and phase 3: evaluation of the test and acquisition of normative data. Test-retest reliability was evaluated in a subgroup of children (n = 27), and the test was validated using children with congenital anosmia (n = 14). Twelve odors were familiar to children and, therefore, included in the U-Sniff test. Children scored a mean ± SD of 9.88 ± 1.80 points out of 12. Normative data was obtained and reported for each country. The U-Sniff test demonstrated a high test-retest reliability (r 27  = 0.83, P < .001) and enabled discrimination between normosmia and children with congenital anosmia with a sensitivity of 100% and specificity of 86%. The U-Sniff is a valid and reliable method of testing olfaction in children and can be used internationally. Copyright © 2018 Elsevier Inc. All rights reserved.

Studies on vaginal malodor. I. Study in humans.

PubMed

Chvapil, M; Eskelson, C; Jacobs, S; Chvapil, T; Russell, D H

1978-07-01

Forty-two percent of collagen sponges tested as an intravaginal barrier contraceptive method developed malodor when retained for 5 days. Only 4% developed odor when the sponge was removed within 24 hours after intercourse, rinsed, and reinserted. While sexually active volunteers found odor in 37% of the sponges, odor formed only in 4% of the sponges worn by sexually inactive users. No difference in the rate of odor formation was found when neutral pH (7.0) and acid pH (3.4) collagen sponges were tested, although we believe that a pH 3.4 is too acid and promotes odor formation. The optimal pH of the sponge should be 4.5 to 5.5. Malodor was efficiently extracted from sponges by washing in acid milieu of tap water and vinegar or 0.1 M acetate buffer, pH 4.0. Alkali extraction procedures were ineffective, and lukewarm water was slightly less effective than acid extraction of odor. At the time of malodor development, the high content of polyamines (putrescine, spermine, spermidine) in the ejaculate decreased to undetectable values. We conclude that the ejaculate is the major source of malodor formation in intravaginally worn collagen sponges. Removal, rinsing optimally in vinegar solution, and reinsertion within 24 hours after intercourse reduces the chance of malodor formation.

Influence of Body Odors and Gender on Perceived Genital Arousal.

PubMed

Alves-Oliveira, Patrícia; Carvalho, Joana; Ferreira, Jacqueline; Alho, Laura; Nobre, Pedro; Olsson, Mats J; Soares, Sandra C

2018-04-01

Olfaction is often linked to mating behavior in nonhumans. Additionally, studies in mating behavior have shown that women seem to be more affected by odor cues than men. However, the relationship between odor cues and sexual response-specifically, sexual arousal-has not been studied yet. The aim of this study was to evaluate the impact of the exposure to human body odors (from individuals of the opposite gender) on perceived genital arousal, while these were presented concomitantly to sexually explicit video clips. Eighty university students (40 women) rated their perceived genital arousal (perceived degree of erection/genital lubrication) in response to an audiovisual sexual stimulus, while simultaneously exposed to a body odor from an opposite-gender donor or no odor. Participants also rated each odor sample's (body odor and no odor) perceived pleasantness, intensity, and familiarity. Findings indicated that odor condition had an effect on women's (but not men's) perceived genital arousal, with women showing higher levels of perceived genital arousal in the no odor condition. Also, results showed that women rated body odors as less pleasant than no odor. Notwithstanding, the odor ratings do not seem to explain the association between body odor and perceived genital arousal. The current results support the hypothesis that women, rather than men, are sensitive to odors in the context of sexual response. The findings of this study have relevance for the understanding of human sexuality with respect to chemosensory communication.

Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identified Odorant Receptor

PubMed Central

Jarriault, David; Grosmaitre, Xavier

2015-01-01

Analyzing the physiological responses of olfactory sensory neurons (OSN) when stimulated with specific ligands is critical to understand the basis of olfactory-driven behaviors and their modulation. These coding properties depend heavily on the initial interaction between odor molecules and the olfactory receptor (OR) expressed in the OSNs. The identity, specificity and ligand spectrum of the expressed OR are critical. The probability to find the ligand of the OR expressed in an OSN chosen randomly within the epithelium is very low. To address this challenge, this protocol uses genetically tagged mice expressing the fluorescent protein GFP under the control of the promoter of defined ORs. OSNs are located in a tight and organized epithelium lining the nasal cavity, with neighboring cells influencing their maturation and function. Here we describe a method to isolate an intact olfactory epithelium and record through patch-clamp recordings the properties of OSNs expressing defined odorant receptors. The protocol allows one to characterize OSN membrane properties while keeping the influence of the neighboring tissue. Analysis of patch-clamp results yields a precise quantification of ligand/OR interactions, transduction pathways and pharmacology, OSNs' coding properties and their modulation at the membrane level.  PMID:26275097

Morphology and physiology of the olfactory system of blood-feeding insects.

PubMed

Guidobaldi, F; May-Concha, I J; Guerenstein, P G

2014-01-01

Several blood-feeding (hematophagous) insects are vectors of a number of diseases including dengue, Chagas disease and leishmaniasis which persistently affect public health throughout Latin America. The vectors of those diseases include mosquitoes, triatomine bugs and sandflies. As vector control is an efficient way to prevent these illnesses it is important to understand the sensory biology of those harmful insects. We study the physiology of the olfactory system of those insects and apply that knowledge on the development of methods to manipulate their behavior. Here we review some of the latest information on insect olfaction with emphasis on hematophagous insects. The insect olfactory sensory neurons are housed inside hair-like organs called sensilla which are mainly distributed on the antenna and mouthparts. The identity of many of the odor compounds that those neurons detect are already known in hematophagous insects. They include several constituents of host (vertebrate) odor, sex, aggregation and alarm pheromones, and compounds related to egg-deposition behavior. Recent work has contributed significant knowledge on how odor information is processed in the insect first odor-processing center in the brain, the antennal lobe. The quality, quantity, and temporal features of the odor stimuli are encoded by the neural networks of the antennal lobe. Information regarding odor mixtures is also encoded. While natural mixtures evoke strong responses, synthetic mixtures that deviate from their natural counterparts in terms of key constituents or proportions of those constituents evoke weaker responses. The processing of olfactory information is largely unexplored in hematophagous insects. However, many aspects of their olfactory behavior are known. As in other insects, responses to relevant single odor compounds are weak while natural mixtures evoke strong responses. Future challenges include studying how information about odor mixtures is processed in their brain. This could help develop highly attractive synthetic odor blends to lure them into traps. Copyright © 2014 Elsevier Ltd. All rights reserved.

Functional transformations of odor inputs in the mouse olfactory bulb.

PubMed

Adam, Yoav; Livneh, Yoav; Miyamichi, Kazunari; Groysman, Maya; Luo, Liqun; Mizrahi, Adi

2014-01-01

Sensory inputs from the nasal epithelium to the olfactory bulb (OB) are organized as a discrete map in the glomerular layer (GL). This map is then modulated by distinct types of local neurons and transmitted to higher brain areas via mitral and tufted cells. Little is known about the functional organization of the circuits downstream of glomeruli. We used in vivo two-photon calcium imaging for large scale functional mapping of distinct neuronal populations in the mouse OB, at single cell resolution. Specifically, we imaged odor responses of mitral cells (MCs), tufted cells (TCs) and glomerular interneurons (GL-INs). Mitral cells population activity was heterogeneous and only mildly correlated with the olfactory receptor neuron (ORN) inputs, supporting the view that discrete input maps undergo significant transformations at the output level of the OB. In contrast, population activity profiles of TCs were dense, and highly correlated with the odor inputs in both space and time. Glomerular interneurons were also highly correlated with the ORN inputs, but showed higher activation thresholds suggesting that these neurons are driven by strongly activated glomeruli. Temporally, upon persistent odor exposure, TCs quickly adapted. In contrast, both MCs and GL-INs showed diverse temporal response patterns, suggesting that GL-INs could contribute to the transformations MCs undergo at slow time scales. Our data suggest that sensory odor maps are transformed by TCs and MCs in different ways forming two distinct and parallel information streams.

Carbon Dioxide and Fruit Odor Transduction in Drosophila Olfactory Neurons. What Controls their Dynamic Properties?

PubMed Central

French, Andrew S.; Meisner, Shannon; Su, Chih-Ying; Torkkeli, Päivi H.

2014-01-01

We measured frequency response functions between odorants and action potentials in two types of neurons in Drosophila antennal basiconic sensilla. CO2 was used to stimulate ab1C neurons, and the fruit odor ethyl butyrate was used to stimulate ab3A neurons. We also measured frequency response functions for light-induced action potential responses from transgenic flies expressing H134R-channelrhodopsin-2 (ChR2) in the ab1C and ab3A neurons. Frequency response functions for all stimulation methods were well-fitted by a band-pass filter function with two time constants that determined the lower and upper frequency limits of the response. Low frequency time constants were the same in each type of neuron, independent of stimulus method, but varied between neuron types. High frequency time constants were significantly slower with ethyl butyrate stimulation than light or CO2 stimulation. In spite of these quantitative differences, there were strong similarities in the form and frequency ranges of all responses. Since light-activated ChR2 depolarizes neurons directly, rather than through a chemoreceptor mechanism, these data suggest that low frequency dynamic properties of Drosophila olfactory sensilla are dominated by neuron-specific ionic processes during action potential production. In contrast, high frequency dynamics are limited by processes associated with earlier steps in odor transduction, and CO2 is detected more rapidly than fruit odor. PMID:24466044

Odor Aversion and Pathogen-Removal Efficiency in Grooming Behavior of the Termite Coptotermes formosanus

PubMed Central

Yanagawa, Aya; Fujiwara-Tsujii, Nao; Akino, Toshiharu; Yoshimura, Tsuyoshi; Yanagawa, Takashi; Shimizu, Susumu

2012-01-01

The results of biocontrol with entomopathogens in termites have been discouraging because of the strong social hygiene behavior for removing pathogens from termite colonies. However, the mechanism of pathogen detection is still unclear. For the successful application of biopesticides to termites in nature, it would be beneficial to identify substances that could disrupt the termite’s ability to perceive pathogens. We hypothesized that termites can perceive pathogens and this ability plays an important role in effective hygiene behavior. In this study, pathogen-detection in the subterranean termite Coptotermes formosanus was investigated. We performed quantitative assays on conidia removal by grooming behavior using epifluoresence microscopy and Y-maze tests to examine the perception of fungal odor by termites. Three species each of high- and low-virulence entomopathogenic fungi were used in each test. The results demonstrated that termites removed conidia more effectively from a nestmate’s cuticle if its odor elicited stronger aversion. Highly virulent pathogens showed higher attachment rates to termite surfaces and their odors were more strongly avoided than those of low-virulence isolates in the same species. Moreover, termites appeared to groom each other more persistently when they had more conidia on their bodies. In brief, insect perception of pathogen-related odor seems to play a role in the mechanism of their hygiene behavior. PMID:23077609

The relation between modeled odor exposure from livestock farming and odor annoyance among neighboring residents.

PubMed

Boers, D; Geelen, L; Erbrink, H; Smit, L A M; Heederik, D; Hooiveld, M; Yzermans, C J; Huijbregts, M; Wouters, I M

2016-04-01

Odor annoyance is an important environmental stressor for neighboring residents of livestock farms and may affect their quality of life and health. However, little is known about the relation between odor exposure due to livestock farming and odor annoyance. Even more, the relation between odor exposure and odor annoyance is rather complicated due to variable responses among individuals to comparable exposure levels and a large number of factors (such as age, gender, education) that may affect the relation. In this study, we (1) investigated the relation between modeled odor exposure and odor annoyance; (2) investigated whether other factors can affect this relation; and (3) compared our dose-response relation to a dose-response relation established in a previous study carried out in the Netherlands, more than 10 years ago, in order to investigate changes in odor perception and appreciation over time. We used data from 582 respondents who participated in a questionnaire survey among neighboring residents of livestock farms in the south of the Netherlands. Odor annoyance was established by two close-ended questions in a questionnaire; odor exposure was estimated using the Stacks dispersion model. The results of our study indicate a statistically significant and positive relation between modeled odor exposure and reported odor annoyance from livestock farming (OR 1.92; 95 % CI 1.53-2.41). Furthermore, age, asthma, education and perceived air pollution in the environment are all related to odor annoyance, although they hardly affect the relation between estimated livestock odor exposure and reported odor annoyance. We also found relatively more odor annoyance reported among neighboring residents than in a previous study conducted in the Netherlands. We found a strong relation between modeled odor exposure and odor annoyance. However, due to some uncertainties and small number of studies on this topic, further research and replication of results is recommended.

Development switch in neural circuitry underlying odor-malaise learning.

PubMed

Shionoya, Kiseko; Moriceau, Stephanie; Lunday, Lauren; Miner, Cathrine; Roth, Tania L; Sullivan, Regina M

2006-01-01

Fetal and infant rats can learn to avoid odors paired with illness before development of brain areas supporting this learning in adults, suggesting an alternate learning circuit. Here we begin to document the transition from the infant to adult neural circuit underlying odor-malaise avoidance learning using LiCl (0.3 M; 1% of body weight, ip) and a 30-min peppermint-odor exposure. Conditioning groups included: Paired odor-LiCl, Paired odor-LiCl-Nursing, LiCl, and odor-saline. Results showed that Paired LiCl-odor conditioning induced a learned odor aversion in postnatal day (PN) 7, 12, and 23 pups. Odor-LiCl Paired Nursing induced a learned odor preference in PN7 and PN12 pups but blocked learning in PN23 pups. 14C 2-deoxyglucose (2-DG) autoradiography indicated enhanced olfactory bulb activity in PN7 and PN12 pups with odor preference and avoidance learning. The odor aversion in weanling aged (PN23) pups resulted in enhanced amygdala activity in Paired odor-LiCl pups, but not if they were nursing. Thus, the neural circuit supporting malaise-induced aversions changes over development, indicating that similar infant and adult-learned behaviors may have distinct neural circuits.

Odorant-binding proteins from a primitive termite.

PubMed

Ishida, Yuko; Chiang, Vicky P; Haverty, Michael I; Leal, Walter S

2002-09-01

Hitherto, odorant-binding proteins (OBPs) have been identified from insects belonging to more highly evolved insect orders (Lepidoptera, Coleoptera, Diptera, Hymenoptera, and Hemiptera), whereas only chemosensory proteins have been identified from more primitive species, such as orthopteran and phasmid species. Here, we report for the first time the isolation and cloning of odorant-binding proteins from a primitive termite species, the dampwood termite. Zootermopsis nevadensis nevadensis (Isoptera: Termopsidae). A major antennae-specific protein was detected by native PAGE along with four other minor proteins, which were also absent in the extract from control tissues (hindlegs). Multiple cDNA cloning led to the full characterization of the major antennae-specific protein (ZnevOBP1) and to the identification of two other antennae-specific cDNAs, encoding putative odorant-binding proteins (ZnevOBP2 and ZnevOBP3). N-terminal amino acid sequencing of the minor antennal bands and cDNA cloning showed that olfaction in Z. n. nevadensis may involve multiple odorant-binding proteins. Database searches suggest that the OBPs from this primitive termite are homologues of the pheromone-binding proteins from scarab beetles and antennal-binding proteins from moths.

Positive relationship between odor identification and affective responses of negatively valenced odors

PubMed Central

Martinec Nováková, Lenka; Plotěná, Dagmar; Roberts, S. Craig; Havlíček, Jan

2015-01-01

Hedonic ratings of odors and olfactory preferences are influenced by a number of modulating factors, such as prior experience and knowledge about an odor’s identity. The present study addresses the relationship between knowledge about an odor’s identity due to prior experience, assessed by means of a test of cued odor identification, and odor pleasantness ratings in children who exhibit ongoing olfactory learning. Ninety-one children aged 8–11 years rated the pleasantness of odors in the Sniffin’ Sticks test and, subsequently, took the odor identification test. A positive association between odor identification and pleasantness was found for two unpleasant food odors (garlic and fish): higher pleasantness ratings were exhibited by those participants who correctly identified these odors compared to those who failed to correctly identify them. However, we did not find a similar effect for any of the more pleasant odors. The results of this study suggest that pleasantness ratings of some odors may be modulated by the knowledge of their identity due to prior experience and that this relationship might be more evident in unpleasant odors. PMID:26029143

Application of two-stage biofilter system for the removal of odorous compounds.

PubMed

Jeong, Gwi-Taek; Park, Don-Hee; Lee, Gwang-Yeon; Cha, Jin-Myeong

2006-01-01

Biofiltration is a biological process which is considered to be one of the more successful examples of biotechnological applications to environmental engineering, and is most commonly used in the removal of odoriferous compounds. In this study, we have attempted to assess the efficiency with which both single and complex odoriferous compounds could be removed, using one- or two-stage biofiltration systems. The tested single odor gases, limonene, alpha-pinene, and iso-butyl alcohol, were separately evaluated in the biofilters. Both limonene and alpha-pinene were removed by 90% or more EC (elimination capacity), 364 g/m3/h and 321 g/m3/h, respectively, at an input concentration of 50 ppm and a retention time of 30 s. The iso-butyl alcohol was maintained with an effective removal yield of more than 90% (EC 375 g/m3/h) at an input concentration of 100 ppm. The complex gas removal scheme was applied with a 200 ppm inlet concentration of ethanol, 70 ppm of acetaldehyde, and 70 ppm of toluene with residence time of 45 s in a one- or two-stage biofiltration system. The removal yield of toluene was determined to be lower than that of the other gases in the one-stage biofilter. Otherwise, the complex gases were sufficiently eliminated by the two-stage biofiltration system.

Chemical composition of scent-gland secretions in an old world monkey (Mandrillus sphinx): influence of sex, male status, and individual identity.

PubMed

Setchell, Joanna M; Vaglio, Stefano; Moggi-Cecchi, Jacopo; Boscaro, Francesca; Calamai, Luca; Knapp, Leslie A

2010-03-01

Primates are traditionally considered to be microsmatic, with decreased reliance on olfactory senses in comparison to other sensory modalities such as vision. This is particularly the case for Old World monkeys and apes (catarrhines). However, various lines of evidence suggest that chemical communication may be important in these species, including the presence of a sternal scent-gland in the mandrill. We investigated the volatile components of mandrill odor using gas chromatography-mass spectrometry. We identified a total of 97 volatile components in 88 swabs of the sternal gland secretion and 95 samples of sternal gland hair saturated with scent-gland secretion collected from 27 males and 18 females. We compared odor profiles with features of the signaler using principle components and discriminant function analyses and found that volatile profiles convey both variable (age, dominance rank in males) and fixed (sex, possibly individual identity) information about the signaler. The combination of an odor profile that signals sex, age, and rank with increased motivation to scent-mark and increased production of secretion in high-ranking males leads to a potent signal of the presence of a dominant, adult male with high testosterone levels. This may be particularly relevant in the dense Central African rain forest which mandrills inhabit. By contrast, we were unable to differentiate between either female cycle stage or female rank based on odor profiles, which accords with behavioral studies suggesting that odor signals are not as important in female mandrills as they are in males. The similarity of our findings to those for other mammals and in primates that are more distantly related to humans suggests a broader role for odor in primate communication than is currently recognized.

Lack of TRPM5-Expressing Microvillous Cells in Mouse Main Olfactory Epithelium Leads to Impaired Odor-Evoked Responses and Olfactory-Guided Behavior in a Challenging Chemical Environment

PubMed Central

Lemons, Kayla; Aoudé, Imad; Ogura, Tatsuya; Mbonu, Kenechukwu; Matsumoto, Ichiro; Arakawa, Hiroyuki

2017-01-01

The mammalian main olfactory epithelium (MOE) modifies its activities in response to changes in the chemical environment. This process is essential for maintaining the functions of the olfactory system and the upper airway. However, mechanisms involved in this functional maintenance, especially those occurring via paracrine regulatory pathways within the multicellular MOE, are poorly understood. Previously, a population of non-neuronal, transient receptor potential M5-expressing microvillous cells (TRPM5-MCs) was identified in the MOE, and the initial characterization of these cells showed that they are cholinergic and responsive to various xenobiotics including odorants at high concentrations. Here, we investigated the role of TRPM5-MCs in maintaining olfactory function using transcription factor Skn-1a knockout (Skn-1a-/-) mice, which lack TRPM5-MCs in the MOE. Under our standard housing conditions, Skn-1a-/- mice do not differ significantly from control mice in odor-evoked electro-olfactogram (EOG) responses and olfactory-guided behaviors, including finding buried food and preference reactions to socially and sexually relevant odors. However, after a 2-wk exposure to high-concentration odor chemicals and chitin powder, Skn-1a-/- mice exhibited a significant reduction in their odor and pheromone-evoked EOG responses. Consequently, their olfactory-guided behaviors were impaired compared with vehicle-exposed Skn-1a-/- mice. Conversely, the chemical exposure did not induce significant changes in the EOG responses and olfactory behaviors of control mice. Therefore, our physiological and behavioral results indicate that TRPM5-MCs play a protective role in maintaining the olfactory function of the MOE. PMID:28612045

Combinatorial effects of odorants on mouse behavior

PubMed Central

Saraiva, Luis R.; Kondoh, Kunio; Ye, Xiaolan; Yoon, Kyoung-hye; Hernandez, Marcus; Buck, Linda B.

2016-01-01

The mechanisms by which odors induce instinctive behaviors are largely unknown. Odor detection in the mouse nose is mediated by >1, 000 different odorant receptors (ORs) and trace amine-associated receptors (TAARs). Odor perceptions are encoded combinatorially by ORs and can be altered by slight changes in the combination of activated receptors. However, the stereotyped nature of instinctive odor responses suggests the involvement of specific receptors and genetically programmed neural circuits relatively immune to extraneous odor stimuli and receptor inputs. Here, we report that, contrary to expectation, innate odor-induced behaviors can be context-dependent. First, different ligands for a given TAAR can vary in behavioral effect. Second, when combined, some attractive and aversive odorants neutralize one another’s behavioral effects. Both a TAAR ligand and a common odorant block aversion to a predator odor, indicating that this ability is not unique to TAARs and can extend to an aversive response of potential importance to survival. In vitro testing of single receptors with binary odorant mixtures indicates that behavioral blocking can occur without receptor antagonism in the nose. Moreover, genetic ablation of a single receptor prevents its cognate ligand from blocking predator odor aversion, indicating that the blocking requires sensory input from the receptor. Together, these findings indicate that innate odor-induced behaviors can depend on context, that signals from a single receptor can block innate odor aversion, and that instinctive behavioral responses to odors can be modulated by interactions in the brain among signals derived from different receptors. PMID:27208093

Analgesia Is Enhanced by Providing Information regarding Good Outcomes Associated with an Odor: Placebo Effects in Aromatherapy?

PubMed Central

Masaoka, Yuri; Kawase, Akiko; Homma, Ikuo

2013-01-01

No previous report has described whether information regarding an odor used in aromatherapy has placebo effects. We investigated whether placebo analgesia was engendered by verbal information regarding the analgesic effects of an odor. Twelve of 24 subjects were provided with the information that a lavender odor would reduce pain (informed), whereas the other 12 subjects were not (not-informed). Concurrent with respiration recording, the subjects were administered a lavender-odor or no-odor treatment during application of painful stimulation to the forefinger. The subjects reported their experience of pain and its unpleasantness on a visual analogue scale after the painful stimulation. The lavender-odor treatment significantly alleviated pain and unpleasantness compared with the no-odor treatment in the informed (P < 0.01) and not-informed groups (P < 0.05). The no-odor treatment in the informed group significantly alleviated pain and unpleasantness compared with both the no-odor and lavender-odor treatments in the not-informed group (P < 0.05). Rapid and shallow breathing induced by the painful stimulation became slow and deep during the lavender-odor and no-odor treatments in both groups. Information regarding a lavender odor, the lavender odor itself, and slower breathing contributed to reduced perceptions of pain and unpleasantness during painful stimulation, suggesting that placebo effects significantly contribute to analgesia in aromatherapy. PMID:23840270

77 FR 22381 - Odorant Fade in Railroad Tank Cars

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-13

... can lead to the loss of odorant. 4. Facilities that load odorized LPG into tank cars take any other... diminished levels of odorant or no odorant present, represents significant safety risks. Absent sufficient... the LPG in the storage tanks at the construction site had virtually no odorant present, explaining why...

Odor and odorous chemical emissions from animal buildings: part 1 - project overview, collection methods, and quality control

USDA-ARS?s Scientific Manuscript database

Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include i...

Ontogeny of Odor-LiCl vs. Odor-Shock Learning: Similar Behaviors but Divergent Ages of Functional Amygdala Emergence

ERIC Educational Resources Information Center

Raineki, Charlis; Shionoya, Kiseko; Sander, Kristin; Sullivan, Regina M.

2009-01-01

Both odor-preference and odor-aversion learning occur in perinatal pups before the maturation of brain structures that support this learning in adults. To characterize the development of odor learning, we compared three learning paradigms: (1) odor-LiCl (0.3M; 1% body weight, ip) and (2) odor-1.2-mA shock (hindlimb, 1sec)--both of which…

Factors affecting the water odor caused by chloramines during drinking water disinfection.

PubMed

Wang, An-Qi; Lin, Yi-Li; Xu, Bin; Hu, Chen-Yan; Gao, Ze-Chen; Liu, Zhi; Cao, Tong-Cheng; Gao, Nai-Yun

2018-10-15

Chloramine disinfection is one of the most common disinfection methods in drinking water treatment. In this study, the temporal variability of water odors during monochloramine auto-decomposition was investigated to elucidate the characteristics of odor problems caused by adopting chloramine disinfection in tap water. Odor intensities and dominant odorant contributions were determined using the flavor profile analysis (FPA) and odor active value (OAV), respectively. During auto-decomposition of monochloramine, Cl 2 /N molar ratio, pH, temperature, and the presence of NOM all affected odor intensity and odor temporal variation in drinking water. In general, decreasing pH from 8.5 to 6.0 led to increasing perceived odor intensity due to the formation of dichloramine. The major odorants responsible for chlorinous odor under acidic and non-acidic conditions were dichloramine and monochloramine, respectively. Chloraminated water with a Cl 2 /N molar ratio of 0.6 or NOM concentration <2 mg-C L -1 inhibited odor intensity. Furthermore, the influence of rechlorination on chlorinous odor intensity for chloraminated water should not be neglected. The results of this study will be beneficial for the control of chlorinous odors caused by chloramine disinfection in drinking water. Copyright © 2018 Elsevier B.V. All rights reserved.

Olfactory experience and the development of odor preference and vaginal marking in female Syrian hamsters.

PubMed

Maras, Pamela M; Petrulis, Aras

2008-07-05

Rodent reproductive behavior relies heavily on odor processing, and evidence suggests that many odor-guided sexual behaviors are shaped by prior experience. We sought to determine if exposure to male odors during development is required for the adult expression of proceptive sexual behavior toward male odors in female Syrian hamsters. Exposure to male odors was restricted in naïve subjects by removing all male siblings from the litter at three to five days of age. Control litters were also culled, but included equal numbers of male and female pups. As adults, naïve females displayed investigatory preferences toward male odors in a Y-maze that were comparable to control females; this preference was observed whether contact with the odor stimuli was prevented of allowed. In contrast, naïve females vaginal scent-marked equally toward male and female volatile odors, suggesting an inability to target behavior toward sexually relevant odors. However, naïve females marked preferentially toward male odors when allowed to contact the odor stimuli. These results provide evidence for the experience-dependent development of vaginal marking behavior toward volatile components of sexual odors. Furthermore, they suggest that distinct mechanisms regulate the development of odor preferences and vaginal marking behavior in this species.

Individually identifiable body odors are produced by the gorilla and discriminated by humans.

PubMed

Hepper, Peter G; Wells, Deborah L

2010-05-01

Many species produce odor cues that enable them to be identified individually, as well as providing other socially relevant information. Study of the role of odor cues in the social behavior of great apes is noticeable by its absence. Olfaction has been viewed as having little role in guiding behavior in these species. This study examined whether Western lowland gorillas produce an individually identifiable odor. Odor samples were obtained by placing cloths in the gorilla's den. A delayed matching to sample task was used with human participants (n = 100) to see if they were able to correctly match a target odor sample to a choice of either: 2 odors (the target sample and another, Experiment 1) and 6 odors (the target sample and 5 others, Experiment 2). Participants were correctly able to identify the target odor when given either 2 or 6 matches. Subjects made fewest errors when matching the odor of the silverback, whereas matching the odors of the young gorillas produced most errors. The results indicate that gorillas do produce individually identifiable body odors and introduce the possibility that odor cues may play a role in gorilla social behavior.

Identification of Rotundone as a Potent Odor-Active Compound of Several Kinds of Fruits.

PubMed

Nakanishi, Akira; Fukushima, Yusuke; Miyazawa, Norio; Yoshikawa, Keisuke; Maeda, Tomoko; Kurobayashi, Yoshiko

2017-06-07

An investigation of the aromas of grapefruit, orange, apple, and mango revealed the presence of an odor-active compound that gave off a strong woody odor when assessed by gas chromatography-olfactometry. We isolated the compound from a high-boiling fraction of an orange essential oil, and subsequent nuclear magnetic resonance analyses of the isolated compound identified it as rotundone. Mass spectra and retention indices obtained from aroma concentrates of grapefruit, apple, and mango were identical to those of rotundone, which was therefore determined to be the common woody compound in these fruits. Sensory analyses were performed to assess the effects of rotundone on model beverages of the various fruits. It was revealed that rotundone added at even subthreshold levels to model beverages did not confer directly the woody odor, but had significant effects on the overall flavors of the beverages, helping them to better approximate the natural flavors of the fruits.

A comparison of methods for the assessment of odor impacts on air quality: Field inspection (VDI 3940) and the air dispersion model CALPUFF

NASA Astrophysics Data System (ADS)

Ranzato, Laura; Barausse, Alberto; Mantovani, Alice; Pittarello, Alberto; Benzo, Maurizio; Palmeri, Luca

2012-12-01

Unpleasant odors are a major cause of public complaints concerning air quality and represent a growing social problem in industrialized countries. However, the assessment of odor pollution is still regarded as a difficult task, because olfactory nuisance can be caused by many different chemical compounds, often found in hard-to-detect concentrations, and the perception of odors is influenced by subjective thresholds; moreover, the impact of odor sources on air quality is mediated by complex atmospheric dispersion processes. The development of standardized assessment approaches to odor pollution and proper international regulatory tools are urgently needed. In particular, comparisons of the methodologies commonly used nowadays to assess odor impacts on air quality are required. Here, we assess the olfactory nuisance caused by an anaerobic treatment plant for municipal solid waste by means of two alternative techniques: the field inspection procedure and the atmospheric dispersion model CALPUFF. Our goal was to compare rigorously their estimates of odor nuisance, both qualitatively (spatial extent of odor impact) and quantitatively (intensity of odor nuisance). To define the impact of odors, we referred to the German standards, based on the frequency of odor episodes in terms of odor hours. We report a satisfying, although not perfect agreement between the estimates provided by the two techniques. For example, they assessed similar spatial extents of odor pollution, but different frequencies of odor episodes in locations where the odor nuisance was highest. The comparison highlights strengths and weaknesses for both approaches. CALPUFF is a cheaper methodology which can be used predictively, but fugitive emissions are difficult to model reliably, because of uncertainty regarding timing, location and emission rate. Field inspection takes into account the role of human perception, but unlike the model it does not always characterize precisely the extent of the odor nuisance caused by a single source when other odors are present, because only the most unpleasant odor is reported. We conclude that these two assessment methods provide reasonable estimates of odor nuisance.

Odor and odorous chemical emissions from animal buildings: Part 3 - chemical emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). The objective of this study was to measure odor emissions and corresponding concentrations and emissions of target odorous gases. Odor and odorous gas measurements at four NAEMS sites (dairy barns in Wisconsin-WI5B...

Odor and odorous chemical emissions from animal buildings: Part 3. Chemical emissions

USDA-ARS?s Scientific Manuscript database

The objective of this study was to measure the long-term odor emissions and corresponding concentrations and emissions of 20 odorous volatile organic compounds (VOCs). This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). Odor and odorous gas measurements at four NAEM...

Odor and chemical emissions from dairy and swine facilities: Part 1 - project overview and collection methods

USDA-ARS?s Scientific Manuscript database

Livestock facilities have received numerous criticisms due to their emissions of odorous air and chemicals. Hence, there is a significant need for odor emission factors and identification of principle odorous chemicals. Odor emission factors are used as inputs to odor setback models, while chemica...

The effect of meat consumption on body odor attractiveness.

PubMed

Havlicek, Jan; Lenochova, Pavlina

2006-10-01

Axillary body odor is individually specific and potentially a rich source of information about its producer. Odor individuality partly results from genetic individuality, but the influence of ecological factors such as eating habits are another main source of odor variability. However, we know very little about how particular dietary components shape our body odor. Here we tested the effect of red meat consumption on body odor attractiveness. We used a balanced within-subject experimental design. Seventeen male odor donors were on "meat" or "nonmeat" diet for 2 weeks wearing axillary pads to collect body odor during the final 24 h of the diet. Fresh odor samples were assessed for their pleasantness, attractiveness, masculinity, and intensity by 30 women not using hormonal contraceptives. We repeated the same procedure a month later with the same odor donors, each on the opposite diet than before. Results of repeated measures analysis of variance showed that the odor of donors when on the nonmeat diet was judged as significantly more attractive, more pleasant, and less intense. This suggests that red meat consumption has a negative impact on perceived body odor hedonicity.

Adaptive regulation of sparseness by feedforward inhibition

PubMed Central

Assisi, Collins; Stopfer, Mark; Laurent, Gilles; Bazhenov, Maxim

2014-01-01

In the mushroom body of insects, odors are represented by very few spikes in a small number of neurons, a highly efficient strategy known as sparse coding. Physiological studies of these neurons have shown that sparseness is maintained across thousand-fold changes in odor concentration. Using a realistic computational model, we propose that sparseness in the olfactory system is regulated by adaptive feedforward inhibition. When odor concentration changes, feedforward inhibition modulates the duration of the temporal window over which the mushroom body neurons may integrate excitatory presynaptic input. This simple adaptive mechanism could maintain the sparseness of sensory representations across wide ranges of stimulus conditions. PMID:17660812

Functional identification and reconstitution of an odorant receptor in single olfactory neurons

PubMed Central

Touhara, Kazushige; Sengoku, Shintaro; Inaki, Koichiro; Tsuboi, Akio; Hirono, Junzo; Sato, Takaaki; Sakano, Hitoshi; Haga, Tatsuya

1999-01-01

The olfactory system is remarkable in its capacity to discriminate a wide range of odorants through a series of transduction events initiated in olfactory receptor neurons. Each olfactory neuron is expected to express only a single odorant receptor gene that belongs to the G protein coupled receptor family. The ligand–receptor interaction, however, has not been clearly characterized. This study demonstrates the functional identification of olfactory receptor(s) for specific odorant(s) from single olfactory neurons by a combination of Ca2+-imaging and reverse transcription–coupled PCR analysis. First, a candidate odorant receptor was cloned from a single tissue-printed olfactory neuron that displayed odorant-induced Ca2+ increase. Next, recombinant adenovirus-mediated expression of the isolated receptor gene was established in the olfactory epithelium by using green fluorescent protein as a marker. The infected neurons elicited external Ca2+ entry when exposed to the odorant that originally was used to identify the receptor gene. Experiments performed to determine ligand specificity revealed that the odorant receptor recognized specific structural motifs within odorant molecules. The odorant receptor-mediated signal transduction appears to be reconstituted by this two-step approach: the receptor screening for given odorant(s) from single neurons and the functional expression of the receptor via recombinant adenovirus. The present approach should enable us to examine not only ligand specificity of an odorant receptor but also receptor specificity and diversity for a particular odorant of interest. PMID:10097159

Earwigs ( Labidura riparia) mimic rotting-flesh odor to deceive vertebrate predators

NASA Astrophysics Data System (ADS)

Byers, John A.

2015-08-01

Many insects repel predators with caustic chemicals, while insects mimicking odors of wastes/dead insects to fool predators have not been documented. We found that the shore earwig, Labidura riparia (Dermaptera: Labiduridae) when bitten by anole lizards, Anolis carolinenesus, spits a rotting-flesh odor that deceives these insectivores into rejecting prey. Once a lizard attacked and rejected an earwig, the lizard did not attack another earwig during several weeks despite consuming other prey, indicating associative learning after one trial. The fetid odor was found in the head-prothorax containing salivary glands of both male and female earwigs and was comprised of ˜100 ng dimethyl disulfide and ˜600 ng dimethyl trisulfide. Nymphs had <5 ng of either compound. Adults also spit odorous sulfides after prolonged attacks by harvester ants, Pogonomyrmex rugosus, who were only deterred by the earwig's forceps. Sulfides released by the earwig are similar to odors of carrion/feces, which may be innately repulsive to some vertebrate predators. The mean initial discharge percentage (IDP) of sulfides from a cohort of earwigs was 62 %; however, IDPs of individuals were highly variable (3-99 %; mean 57 %). The discharge refill time (DRT) to refill 50 % of the earwig's allomone reservoir was estimated at 13 h. A positive relationship in sulfide amounts with body weight was found only in females in 2009, suggesting metabolic cost tradeoffs were revealed when sulfide content was half that in 2010. This is the first report of insects releasing sulfur-containing compounds that may mimic carrion-fecal odors as a deceptive defense against vertebrate predators.

Detection of pup odors by non-canonical adult vomeronasal neurons expressing an odorant receptor gene is influenced by sex and parenting status.

PubMed

Nakahara, Thiago S; Cardozo, Leonardo M; Ibarra-Soria, Ximena; Bard, Andrew D; Carvalho, Vinicius M A; Trintinalia, Guilherme Z; Logan, Darren W; Papes, Fabio

2016-02-15

Olfaction is a fundamental sense through which most animals perceive the external world. The olfactory system detects odors via specialized sensory organs such as the main olfactory epithelium and the vomeronasal organ. Sensory neurons in these organs use G-protein coupled receptors to detect chemosensory stimuli. The odorant receptor (OR) family is expressed in sensory neurons of the main olfactory epithelium, while the adult vomeronasal organ is thought to express other types of receptors. Here, we describe Olfr692, a member of the OR gene family identified by next-generation RNA sequencing, which is highly upregulated and non-canonically expressed in the vomeronasal organ. We show that neurons expressing this gene are activated by odors emanating from pups. Surprisingly, activity in Olfr692-positive cells is sexually dimorphic, being very low in females. Our results also show that juvenile odors activate a large number of Olfr692 vomeronasal neurons in virgin males, which is correlated with the display of infanticide behavior. . In contrast, activity substantially decreases in parenting males (fathers), where infanticidal aggressive behavior is not frequently observed. Our results describe, for the first time, a sensory neural population with a specific molecular identity involved in the detection of pup odors. Moreover, it is one of the first reports of a group of sensory neurons the activity of which is sexually dimorphic and depends on social status. Our data suggest that the Olfr692 population is involved in mediating pup-oriented behaviors in mice.

Behavioral responses to mammalian blood odor and a blood odor component in four species of large carnivores.

PubMed

Nilsson, Sara; Sjöberg, Johanna; Amundin, Mats; Hartmann, Constanze; Buettner, Andrea; Laska, Matthias

2014-01-01

Only little is known about whether single volatile compounds are as efficient in eliciting behavioral responses in animals as the whole complex mixture of a behaviorally relevant odor. Recent studies analysing the composition of volatiles in mammalian blood, an important prey-associated odor stimulus for predators, found the odorant trans-4,5-epoxy-(E)-2-decenal to evoke a typical "metallic, blood-like" odor quality in humans. We therefore assessed the behavior of captive Asian wild dogs (Cuon alpinus), African wild dogs (Lycaon pictus), South American bush dogs (Speothos venaticus), and Siberian tigers (Panthera tigris altaica) when presented with wooden logs that were impregnated either with mammalian blood or with the blood odor component trans-4,5-epoxy-(E)-2-decenal, and compared it to their behavior towards a fruity odor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate) as control. We found that all four species displayed significantly more interactions with the odorized wooden logs such as sniffing, licking, biting, pawing, and toying, when they were impregnated with the two prey-associated odors compared to the two non-prey-associated odors. Most importantly, no significant differences were found in the number of interactions with the wooden logs impregnated with mammalian blood and the blood odor component in any of the four species. Only one of the four species, the South American bush dogs, displayed a significant decrease in the number of interactions with the odorized logs across the five sessions performed per odor stimulus. Taken together, the results demonstrate that a single blood odor component can be as efficient in eliciting behavioral responses in large carnivores as the odor of real blood, suggesting that trans-4,5-epoxy-(E)-2-decenal may be perceived by predators as a "character impact compound" of mammalian blood odor. Further, the results suggest that odorized wooden logs are a suitable manner of environmental enrichment for captive carnivores.

Addition of Olfactory Stimuli to Virtual Reality Simulations for Medical Training Applications

DTIC Science & Technology

1996-11-01

surveyed and a working set of odorants were indentified or developed in sufficient quantities to support further testing. Extensive studies were performed...Olfactory Displays for HMD Systems 8 Ambulatory Olfactory HMD Display 11 Odor Display--Booth Environment 19 Odor Display in CAVE 20 Odor Survey and Odor...HMDs, it may be welcome in some scenarios such as those that might be used for training medics. Odorant Survey and Odor Development A second area of

Blocking adenylyl cyclase inhibits olfactory generator currents induced by "IP(3)-odors".

PubMed

Chen, S; Lane, A P; Bock, R; Leinders-Zufall, T; Zufall, F

2000-07-01

Vertebrate olfactory receptor neurons (ORNs) transduce odor stimuli into electrical signals by means of an adenylyl cyclase/cAMP second messenger cascade, but it remains widely debated whether this cAMP cascade mediates transduction for all odorants or only certain odor classes. To address this problem, we have analyzed the generator currents induced by odors that failed to produce cAMP in previous biochemical assays but instead produced IP(3) ("IP(3)-odors"). We show that in single salamander ORNs, sensory responses to "cAMP-odors" and IP(3)-odors are not mutually exclusive but coexist in the same cells. The currents induced by IP(3)-odors exhibit identical biophysical properties as those induced by cAMP odors or direct activation of the cAMP cascade. By disrupting adenylyl cyclase to block cAMP formation using two potent antagonists of adenylyl cyclase, SQ22536 and MDL12330A, we show that this molecular step is necessary for the transduction of both odor classes. To assess whether these results are also applicable to mammals, we examine the electrophysiological responses to IP(3)-odors in intact mouse main olfactory epithelium (MOE) by recording field potentials. The results show that inhibition of adenylyl cyclase prevents EOG responses to both odor classes in mouse MOE, even when "hot spots" with heightened sensitivity to IP(3)-odors are examined.

Odor and odorous chemical emissions from dairy and swine facilities: Part 5-Simultaneous chemical and sensory analysis with Gas Chromatography - Mass Spectrometry - Olfactometry

USDA-ARS?s Scientific Manuscript database

Simultaneous chemical and sensory analyses using gas chromatography-mass spectrometry-olfactometry (GC-MS-O) for air samples collected at barn exhaust fans were used for quantification and ranking of odor impact of target odorous gases. Fifteen target odorous VOCs (odorants) were selected. Air sampl...

Numerical Simulation of Airway Dimension Effects on Airflow Patterns and Odorant Deposition Patterns in the Rat Nasal Cavity

PubMed Central

Wei, Zehong; Xu, Zhixiang; Li, Bo; Xu, Fuqiang

2013-01-01

The sense of smell is largely dependent on the airflow and odorant transport in the nasal cavity, which in turn depends on the anatomical structure of the nose. In order to evaluate the effect of airway dimension on rat nasal airflow patterns and odorant deposition patterns, we constructed two 3-dimensional, anatomically accurate models of the left nasal cavity of a Sprague-Dawley rat: one was based on high-resolution MRI images with relatively narrow airways and the other was based on artificially-widening airways of the MRI images by referencing the section images with relatively wide airways. Airflow and odorant transport, in the two models, were determined using the method of computational fluid dynamics with finite volume method. The results demonstrated that an increase of 34 µm in nasal airway dimension significantly decreased the average velocity in the whole nasal cavity by about 10% and in the olfactory region by about 12% and increased the volumetric flow into the olfactory region by about 3%. Odorant deposition was affected to a larger extent, especially in the olfactory region, where the maximum odorant deposition difference reached one order of magnitude. The results suggest that a more accurate nasal cavity model is necessary in order to more precisely study the olfactory function of the nose when using the rat. PMID:24204875

[Odor sensing system and olfactory display].

PubMed

Nakamoto, Takamichi

2014-01-01

In this review, an odor sensing system and an olfactory display are introduced into people in pharmacy. An odor sensing system consists of an array of sensors with partially overlapping specificities and pattern recognition technique. One of examples of odor sensing systems is a halitosis sensor which quantifies the mixture composition of three volatile sulfide compounds. A halitosis sensor was realized using a preconcentrator to raise sensitivity and an electrochemical sensor array to suppress the influence of humidity. Partial least squares (PLS) method was used to quantify the mixture composition. The experiment reveals that the sufficient accuracy was obtained. Moreover, the olfactory display, which present scents to human noses, is explained. A multi-component olfactory display enables the presentation of a variety of smells. The two types of multi-component olfactory display are described. The first one uses many solenoid valves with high speed switching. The valve ON frequency determines the concentration of the corresponding odor component. The latter one consists of miniaturized liquid pumps and a surface acoustic wave (SAW) atomizer. It enables the wearable olfactory display without smell persistence. Finally, the application of the olfactory display is demonstrated. Virtual ice cream shop with scents was made as a content of interactive art. People can enjoy harmony among vision, audition and olfaction. In conclusion, both odor sensing system and olfactory display can contribute to the field of human health care.

Smelling chemosensory signals of males in anxious versus nonanxious condition increases state anxiety of female subjects.

PubMed

Albrecht, Jessica; Demmel, Maria; Schöpf, Veronika; Kleemann, Anna Maria; Kopietz, Rainer; May, Johanna; Schreder, Tatjana; Zernecke, Rebekka; Brückmann, Hartmut; Wiesmann, Martin

2011-01-01

The hypothesis of this experiment was that humans in an anxious state compared with a nonanxious state are able to increase anxiety levels in other humans via their body odors. Specifically, we hypothesized that male chemosensory anxiety signals compared with neutral chemosignals increase state anxiety of female subjects. Thirteen male subjects participated in 2 different sweat donation sessions: chemosignals were collected during participation in a high rope course (anxiety condition) and in an ergometer workout (neutral condition). State and trait anxiety were evaluated in 20 female odor recipients using Spielberger's state-trait anxiety inventory in a double-blind design. Comparison of state anxiety of odor donors between control and anxiety condition differed significantly indicating that our model of anxiety induction successfully led to the expected change in emotion. Comparison of state anxiety of odor recipients showed a trend toward higher state anxiety in the anxiety condition compared with the neutral condition after 5 min of odor exposure. After 20 min of odor exposure, state anxiety of female subjects was significantly higher during the perception of sweat collected during the anxiety condition in comparison with the perception of sweat collected during the neutral condition. This experiment gives evidence that male anxiety chemosignals compared with neutral chemosignals are capable of inducing an increased state anxiety in female subjects.

Distributions of four taste and odor compounds in the sediment and overlying water at different ecology environment in Taihu Lake.

PubMed

Huang, Heyong; Xu, Xiaoguang; Liu, Xiansheng; Han, Ruiming; Liu, Jine; Wang, Guoxiang

2018-04-18

Organic matter-induced black blooms, such as cyanobacterial and vegetation blooms, are a serious ecosystem disasters that have occurred in Taihu Lake. After large-scale outbreaks of blooms in eutrophic water, a large number of cyanobacterial and vegetation residue accumulate in the coastal areas, and rapidly fermented into odorous compounds. In this study, four taste and odor compounds have been analyzed in sediments and overlying water of different ecology environment in Taihu Lake. High concentrations of DMDS (up to 7165.25 ngg -1  dw -1 ), DMTS (up to 50.93 ngg -1  dw -1 ), β-cyclocitral (up to 5441.69 ngg -1  dw -1 ), β-ionone (up to 1669.37 ngg -1  dw -1 ) were detected in sediments. Also, the spatial distributions of DMDS, DMTS, β-cyclocitral and β-ionone in the sediments were investigated. As the depth of sediment increases, nutrients and odorous compounds are greatly reduced. The results showed that during the degradation of cyanobacterial and vegetation residues, DMDS, DMTS, β-cyclocitral, β-ionone and nutrients are gradually released. In addition, when assessing the source of odorous compounds in overlying water, it should also be considered that it may be released from the sediment. This study shows that odorous compounds are ubiquitous in near-shore zones Taihu Lake, and may take potential hazard to aquatic ecosystems.

Field Air Sampling and Simultaneous Chemical and Sensory Analysis of Livestock Odorants with Sorbent Tube GC-MS/Olfactometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Shicheng; Department of Environmental Science and Engineering, Fudan University, Shanghai 200433; Cai Lingshuang

2009-05-23

Characterization and quantification of livestock odorants is one of the most challenging analytical tasks because odor-causing gases are very reactive, polar and often present at very low concentrations in a complex matrix of less important or irrelevant gases. The objective of this research was to develop a novel analytical method for characterization of the livestock odorants including their odor character, odor intensity, and hedonic tone and to apply this method for quantitative analysis of the key odorants responsible for livestock odor. Sorbent tubes packed with Tenax TA were used for field sampling. The automated one-step thermal desorption module coupled withmore » multidimensional gas chromatography-mass spectrometry/olfactometry system was used for simultaneous chemical and odor analysis. Fifteen odorous VOCs and semi-VOCs identified from different livestock species operations were quantified. Method detection limits ranges from 40 pg for skatole to 3590 pg for acetic acid. In addition, odor character, odor intensity and hedonic tone associated with each of the target odorants are also analyzed simultaneously. We found that the mass of each VOCs in the sample correlates well with the log stimulus intensity. All of the correlation coefficients (R{sup 2}) are greater than 0.74, and the top 10 correlation coefficients were greater than 0.90.« less

Odor Sampling: Techniques and Strategies for the Estimation of Odor Emission Rates from Different Source Types

PubMed Central

Capelli, Laura; Sironi, Selena; Rosso, Renato Del

2013-01-01

Sampling is one of the main issues pertaining to odor characterization and measurement. The aim of sampling is to obtain representative information on the typical characteristics of an odor source by means of the collection of a suitable volume fraction of the effluent. The most important information about an emission source for odor impact assessment is the so-called Odor Emission Rate (OER), which represents the quantity of odor emitted per unit of time, and is expressed in odor units per second (ou·s−1). This paper reviews the different odor sampling strategies adopted depending on source type. The review includes an overview of odor sampling regulations and a detailed discussion of the equipment to be used as well as the mathematical considerations to be applied to obtain the OER in relation to the sampled source typology. PMID:23322098

[Perception of odor quality by Free Image-Association Test].

PubMed

Ueno, Y

1992-10-01

A method was devised for evaluating odor quality. Subjects were requested to freely describe the images elicited by smelling odors. This test was named the "Free Image-Association Test (FIT)". The test was applied for 20 flavors of various foods, five odors from the standards of T&T olfactometer (Japanese standard olfactory test), butter of yak milk, and incense from Lamaism temples. The words for expressing imagery were analyzed by multidimensional scaling and cluster analysis. Seven clusters of odors were obtained. The feature of these clusters were quite similar to that of primary odors which have been suggested by previous studies. However, the clustering of odors can not be explained on the basis of the primary-odor theory, but the information processing theory originally proposed by Miller (1956). These results support the usefulness of the Free Image-Association Test for investigating odor perception based on the images associated with odors.

Odor-evoked inhibition of olfactory sensory neurons drives olfactory perception in Drosophila.

PubMed

Cao, Li-Hui; Yang, Dong; Wu, Wei; Zeng, Xiankun; Jing, Bi-Yang; Li, Meng-Tong; Qin, Shanshan; Tang, Chao; Tu, Yuhai; Luo, Dong-Gen

2017-11-07

Inhibitory response occurs throughout the nervous system, including the peripheral olfactory system. While odor-evoked excitation in peripheral olfactory cells is known to encode odor information, the molecular mechanism and functional roles of odor-evoked inhibition remain largely unknown. Here, we examined Drosophila olfactory sensory neurons and found that inhibitory odors triggered outward receptor currents by reducing the constitutive activities of odorant receptors, inhibiting the basal spike firing in olfactory sensory neurons. Remarkably, this odor-evoked inhibition of olfactory sensory neurons elicited by itself a full range of olfactory behaviors from attraction to avoidance, as did odor-evoked olfactory sensory neuron excitation. These results indicated that peripheral inhibition is comparable to excitation in encoding sensory signals rather than merely regulating excitation. Furthermore, we demonstrated that a bidirectional code with both odor-evoked inhibition and excitation in single olfactory sensory neurons increases the odor-coding capacity, providing a means of efficient sensory encoding.

Odor sampling: techniques and strategies for the estimation of odor emission rates from different source types.

PubMed

Capelli, Laura; Sironi, Selena; Del Rosso, Renato

2013-01-15

Sampling is one of the main issues pertaining to odor characterization and measurement. The aim of sampling is to obtain representative information on the typical characteristics of an odor source by means of the collection of a suitable volume fraction of the effluent. The most important information about an emission source for odor impact assessment is the so-called Odor Emission Rate (OER), which represents the quantity of odor emitted per unit of time, and is expressed in odor units per second (ou∙s-1). This paper reviews the different odor sampling strategies adopted depending on source type. The review includes an overview of odor sampling regulations and a detailed discussion of the equipment to be used as well as the mathematical considerations to be applied to obtain the OER in relation to the sampled source typology.

Discriminating the stimulus elements during human odor-taste learning: a successful analytic stance does not eliminate learning.

PubMed

Stevenson, Richard J; Mahmut, Mehmet K

2011-10-01

Odor "sweetness" may arise from experiencing odors and tastes together, resulting in a flavor memory that is later reaccessed by the odor. Forming a flavor memory may be impaired if the taste and odor elements are apparent during exposure, suggesting that configural processing may underpin learning. Using a new procedure, participants made actual flavor discriminations for one odor-taste pair (e.g., Taste A vs. Odor X-Taste A) and mock discriminations for another (e.g., Odor Y-Taste B vs. Odor Y-Taste B). Participants, who were successful at detecting the actual flavor discriminations, demonstrated equal amounts of learning for both odor-taste pairings. These results suggest that although a capacity to discriminate flavor into its elements may be necessary to support learning, whether participants experience a configural or elemental flavor representation may not.

Order of exposure to pleasant and unpleasant odors affects autonomic nervous system response.

PubMed

Horii, Yuko; Nagai, Katsuya; Nakashima, Toshihiro

2013-04-15

When mammals are exposed to an odor, that odor is expected to elicit a physiological response in the autonomic nervous system. An unpleasant aversive odor causes non-invasive stress, while a pleasant odor promotes healing and relaxation in mammals. We hypothesized that pleasant odors might reduce a stress response previously induced by an aversive predator odor. Rats were thus exposed to pleasant and unpleasant odors in different orders to determine whether the order of odor exposure had an effect on the physiological response in the autonomic nervous system. The first trial examined autonomic nerve activity via sympathetic and parasympathetic nerve response while the second trial examined body temperature response. Initial exposure to a pleasant odor elicited a positive response and secondary exposure to an unpleasant odor elicited a negative response, as expected. However, we found that while initial exposure to an unpleasant odor elicited a negative stress response, subsequent secondary exposure to a pleasant odor not only did not alleviate that negative response, but actually amplified it. These findings were consistent for both the autonomic nerve activity response trial and the body temperature response trial. The trial results suggest that exposure to specific odors does not necessarily result in the expected physiological response and that the specific order of exposure plays an important role. Our study should provide new insights into our understanding of the physiological response in the autonomic nervous system related to odor memory and discrimination and point to areas that require further research. Copyright © 2013 Elsevier B.V. All rights reserved.

OdorMapComparer: an application for quantitative analyses and comparisons of fMRI brain odor maps.

PubMed

Liu, Nian; Xu, Fuqiang; Miller, Perry L; Shepherd, Gordon M

2007-01-01

Brain odor maps are reconstructed flat images that describe the spatial activity patterns in the glomerular layer of the olfactory bulbs in animals exposed to different odor stimuli. We have developed a software application, OdorMapComparer, to carry out quantitative analyses and comparisons of the fMRI odor maps. This application is an open-source window program that first loads two odor map images being compared. It allows image transformations including scaling, flipping, rotating, and warping so that the two images can be appropriately aligned to each other. It performs simple subtraction, addition, and average of signals in the two images. It also provides comparative statistics including the normalized correlation (NC) and spatial correlation coefficient. Experimental studies showed that the rodent fMRI odor maps for aliphatic aldehydes displayed spatial activity patterns that are similar in gross outlines but somewhat different in specific subregions. Analyses with OdorMapComparer indicate that the similarity between odor maps decreases with increasing difference in the length of carbon chains. For example, the map of butanal is more closely related to that of pentanal (with a NC = 0.617) than to that of octanal (NC = 0.082), which is consistent with animal behavioral studies. The study also indicates that fMRI odor maps are statistically odor-specific and repeatable across both the intra- and intersubject trials. OdorMapComparer thus provides a tool for quantitative, statistical analyses and comparisons of fMRI odor maps in a fashion that is integrated with the overall odor mapping techniques.

Emotional Responses to Odors in Children with High-Functioning Autism: Autonomic Arousal, Facial Behavior and Self-Report

ERIC Educational Resources Information Center

Legisa, Jasna; Messinger, Daniel S.; Kermol, Enzo; Marlier, Luc

2013-01-01

Although emotional functioning is impaired in children with autism, it is unclear if this impairment is due to difficulties with facial expression, autonomic responsiveness, or the verbal description of emotional states. To shed light on this issue, we examined responses to pleasant and unpleasant odors in eight children (8-14 years) with…

Evaluation of the Effectiveness of Five Odor Reducing Agents for Sewer System Odors Using an On-Line Total Reduced Sulfur Analyzer

PubMed Central

Choi, Il; Lee, Hyunjoo; Shin, Joungdu; Kim, Hyunook

2012-01-01

Sewer odors have been a concern to citizens of the Metropolitan Seoul region, which has installed combined sewer systems (CSSs) in 86% of its area. Although a variety of odorants are released from sewers, volatile sulfur compounds (VSCs) have been recognized as major ones. A number of technologies have been proposed to monitor or control odors from sewers. One of the most popular strategies adopted for the control of sewage odor is by applying a commercial odor-reducing agent into the sewer. In this study, the effectiveness of five different commercial odor-reducing agents (i.e., an odor masking agent, an alkaline solution, two microbial agents, and a chemical oxidant) was evaluated by continuously monitoring VSCs released from the sewer with an on-line total reduced sulfur (TRS) analyzer before and after each agent was sprayed into CSSs at five different locations of the city. In short, when the effectiveness of odor treatment was tested in the sewer system using five commercial odor reducing treatments, only the chemical oxidant was good enough to reduce the odor in terms of TRS levels measured before and after the application (p < 0.01). PMID:23223148

An odor interaction model of binary odorant mixtures by a partial differential equation method.

PubMed

Yan, Luchun; Liu, Jiemin; Wang, Guihua; Wu, Chuandong

2014-07-09

A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE) method. Based on the measurement method (tangent-intercept method) of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture's odor intensity to the individual odorant's relative odor activity value (OAV). Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors) also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.

Recruits of the stingless bee Scaptotrigona pectoralis learn food odors from the nest atmosphere.

PubMed

Reichle, Christian; Jarau, Stefan; Aguilar, Ingrid; Ayasse, Manfred

2010-05-01

The ability to learn food odors inside the nest and to associate them with food sources in the field is of essential importance for the recruitment of nestmates in social bees. We investigated odor learning by workers within the hive and the influence of these odors on their food choice in the field in the stingless bee Scaptotrigona pectoralis. During the experiments, recruited bees had to choose between two feeders, one with an odor that was present inside the nest during the recruitment process, and one with an unknown odor. In all experiments with different odor combinations (linalool/phenylacetaldehyde, geraniol/eugenol) a significant majority of bees visited the feeder with the odor they had experienced in their nest (chi (2)-tests; p < 0.05). By contrast, the bees showed no preference for one of two feeders when they were either baited with the same odor (linalool) or contained no odor. Our results clearly show that naïve workers of S. pectoralis can learn the odor of a food source during the recruitment process from the nest atmosphere and that their subsequent food search in the field is influenced by the learned odor.

Odor compounds in waste gas emissions from agricultural operations and food industries.

PubMed

Rappert, S; Müller, R

2005-01-01

In the last decades, large-scale agricultural operations and food industries have increased. These operations generate numerous types of odors. The reduction of land areas available for isolation of agricultural and food processing industrial operations from the public area and the increase in sensitivity and demand of the general public for a clean and pleasant environment have forced all of these industries to control odor emissions and toxic air pollutants. To develop environmentally sound, sustainable agricultural and food industrial operations, it is necessary to integrate research that focuses on modern analytical techniques and latest sensory technology of measurement and evaluation of odor and pollution, together with a fundamental knowledge of factors that are the basic units contributing to the production of odor and pollutants. Without a clear understanding of what odor is, how to measure it, and where it originates, it will be difficult to control the odor. The present paper reviews the available information regarding odor emissions from agricultural operations and food industries by giving an overview about odor problems, odor detection and quantification, and identifying the sources and the mechanisms that contribute to the odor emissions. Finally, ways of reducing or controlling the odor problem are discussed.

Recruits of the stingless bee Scaptotrigona pectoralis learn food odors from the nest atmosphere

NASA Astrophysics Data System (ADS)

Reichle, Christian; Jarau, Stefan; Aguilar, Ingrid; Ayasse, Manfred

2010-05-01

The ability to learn food odors inside the nest and to associate them with food sources in the field is of essential importance for the recruitment of nestmates in social bees. We investigated odor learning by workers within the hive and the influence of these odors on their food choice in the field in the stingless bee Scaptotrigona pectoralis. During the experiments, recruited bees had to choose between two feeders, one with an odor that was present inside the nest during the recruitment process, and one with an unknown odor. In all experiments with different odor combinations (linalool/phenylacetaldehyde, geraniol/eugenol) a significant majority of bees visited the feeder with the odor they had experienced in their nest ( χ 2-tests; p < 0.05). By contrast, the bees showed no preference for one of two feeders when they were either baited with the same odor (linalool) or contained no odor. Our results clearly show that naïve workers of S. pectoralis can learn the odor of a food source during the recruitment process from the nest atmosphere and that their subsequent food search in the field is influenced by the learned odor.

The effects of predator odors in mammalian prey species: a review of field and laboratory studies.

PubMed

Apfelbach, Raimund; Blanchard, Caroline D; Blanchard, Robert J; Hayes, R Andrew; McGregor, Iain S

2005-01-01

Prey species show specific adaptations that allow recognition, avoidance and defense against predators. For many mammalian species this includes sensitivity towards predator-derived odors. The typical sources of such odors include predator skin and fur, urine, feces and anal gland secretions. Avoidance of predator odors has been observed in many mammalian prey species including rats, mice, voles, deer, rabbits, gophers, hedgehogs, possums and sheep. Field and laboratory studies show that predator odors have distinctive behavioral effects which include (1) inhibition of activity, (2) suppression of non-defensive behaviors such as foraging, feeding and grooming, and (3) shifts to habitats or secure locations where such odors are not present. The repellent effect of predator odors in the field may sometimes be of practical use in the protection of crops and natural resources, although not all attempts at this have been successful. The failure of some studies to obtain repellent effects with predator odors may relate to (1) mismatches between the predator odors and prey species employed, (2) strain and individual differences in sensitivity to predator odors, and (3) the use of predator odors that have low efficacy. In this regard, a small number of recent studies have suggested that skin and fur-derived predator odors may have a more profound lasting effect on prey species than those derived from urine or feces. Predator odors can have powerful effects on the endocrine system including a suppression of testosterone and increased levels of stress hormones such as corticosterone and ACTH. Inhibitory effects of predator odors on reproductive behavior have been demonstrated, and these are particularly prevalent in female rodent species. Pregnant female rodents exposed to predator odors may give birth to smaller litters while exposure to predator odors during early life can hinder normal development. Recent research is starting to uncover the neural circuitry activated by predator odors, leading to hypotheses about how such activation leads to observable effects on reproduction, foraging and feeding.

Ventilation requirements in buildings—I. Control of occupancy odor and tobacco smoke odor

NASA Astrophysics Data System (ADS)

Cain, William S.; Leaderer, Brian P.; Isseroff, Ruth; Berglund, Larry G.; Huey, Raymond J.; Lipsitt, Eric D.; Perlman, Dan

Psychophysical measurements of odor, supplemented with certain physical measurements, were taken to examine ventilation requirements during smoking and nonsmoking occupancy in an environmental chamber. The facility provided the means to compare impressions of visitors (persons who inhaled air from the chamber only briefly) with impressions of occupants. For nonsmoking occupancy, 47 combinations of temperature, humidity, ventilation rate and occupancy density were examined. Odor level depended entirely on ventilation rate per person irrespective of the number of persons in the chamber. The ventilation necessary to satisfy 75 % of visitors equalled only about 4 ℓ s -1 per person. Occupants, however, were satisfied with far less. In an array of 38 conditions of smoking occupancy, the ventilation deemed necessary to satisfy 75 % of visitors under customary conditions of occupancy equalled 17.5 ℓ s -1 per person. For both smoking and nonsmoking conditions, a combination of high temperature (25.5°C) and humidity (r.h. > 70 %) exacerbated the odor problem. During smoking, carbon monoxide rarely reached dangerous levels, but suspended particulate matter often reached levels considered unacceptable outdoors. The results highlight the energy penalty incurred in ventilation for smoking occupancy.

Freshness assessments of Moroccan sardine (Sardina pilchardus): comparison of overall sensory changes to instrumentally determined volatiles.

PubMed

Triqui, Réda; Bouchriti, Nourredine

2003-12-17

Freshness of ice-stored sardine was assessed by two sensory methods, the quality index method (QIM) and the European Union freshness grading system, and by instrumental means using the method of aroma extract dilution analysis. Screening of sardine potent volatiles was carried out at three freshness stages. In the very fresh state, the plant-like fresh volatiles dominated the odor pattern, with the exception of methional. Overall odor changes in sardine throughout storage correlated with changes in the concentration of some potent volatiles: after 2 days of ice storage, (Z)-4-heptenal, (Z)-1,5-octadien-3-one, and methional imparted an overall "fishy" odor character to sardine, whereas at a lower sensory grade (B), the compounds (E)-2-nonenal and (E,Z)-2,6-nonadienal could be, in part, associated with the slightly rancid aroma top notes. Trimethylamine was detected as a highly volatile odorant using solid-phase microextraction (SPME) headspace analysis of refrigerator-stored sardine. Intensity and sensory characteristics of some SPME determined volatiles, for example, 3-methylnonane-2,4-dione, were closely related to overall odor changes. SPME headspace analysis may be useful in the characterization of off-flavors in fish.

Transfer behavior of odorous pollutants in wastewater sludge system under typical chemical conditioning processes for dewaterability enhancement.

PubMed

Gao, Hongyu; Zhang, Weijun; Song, Zhenzhen; Yang, Xiaofang; Yang, Lian; Cao, Mengdi; Wang, Dongsheng; Liao, Guiying

2017-06-13

Chemical conditioning has been used for enhancing wastewater sludge dewaterability for many years, but the characteristics of odorous pollutants emission in sludge conditioning were still unclear. In this work, the transfer behavior of different odorous pollutants between air, liquid and solid phases under typical chemical conditioning processes for high-pressure dewatering was systematically investigated. The results indicated that that besides hydrogen sulfide (H 2 S) and ammonia (NH 3 ), 21 kinds of volatile organic contaminants (VOCs) were identified and quantified by gas chromatography-mass spectrometry (GC-MS), while the concentrations and composition of odorous pollutants varied greatly for different conditioning processes. VOCs were composed by three main constituents including benzenes, halogeno benzene and hydrocarbons. According to mass balance analysis, about 50% of VOCs adsorbed within sludge extracellular polymeric substances (EPS) fraction. Since EPS was damaged and/or flocculation in different chemical conditioning processes, VOCs distributed in solid phase transformed into liquid phase and then released into air. The discrepancies in mass of odorous pollutants before and after chemical conditioning were likely to be related to chemical conversion under acidification, oxidation and precipitation in the presence of ferric ions.

Characterization of odor-active volatiles in apples: influence of cultivars and maturity stage.

PubMed

Mehinagic, Emira; Royer, Gaëlle; Symoneaux, Ronan; Jourjon, Frédérique; Prost, Carole

2006-04-05

The aroma and texture of three different apple cultivars, harvested at three maturity stages, were analyzed by sensory and instrumental analysis. The emphasis was on the identification of the most potent odorant volatiles, and the challenge was to separate the few most important flavor compounds, which may be trace chemicals, from the vast number of nonodorant compounds present in apple aroma extracts. Thirty-six odorant compounds were detected, 24 of which were common to all extracts. A significant correlation coefficient was found between the aroma intensity scores and overall quantity of the odorant volatiles, which shows that the development of sensory aroma is similar to that of odorant volatiles. This study also showed that the parameters measured by penetrometry and compression were highly correlated with sensory textural attributes. The determination of the optimal maturity stage for different apple cultivars by the usual parameters, such as color, diameter, total soluble solids, and titrable acidity, may not be sufficient to determine the optimal sensory quality for consumers. Moreover, the sensory quality of fruits changes during maturation in a different way from one cultivar to another, and this should be taken into account.

Characterization and quantification of odor-active compounds in unsaturated fatty acid/conjugated linoleic acid (UFA/CLA)-enriched butter and in conventional butter during storage and induced oxidation.

PubMed

Mallia, Silvia; Escher, Felix; Dubois, Sébastien; Schieberle, Peter; Schlichtherle-Cerny, Hedwig

2009-08-26

Dairy products enriched in unsaturated fatty acids (UFA) and conjugated linoleic acids (CLA) have a higher nutritional value and are suggested to have beneficial health effects. However, such acids are susceptible to oxidation, and off-flavors may be formed during storage. This study was aimed to compare the most important odorants in UFA/CLA-enriched butter to that of conventional butter during storage and induced oxidation. Volatiles were isolated by solvent-assisted flavor evaporation and identified by gas chromatography-olfactometry and mass spectrometry. Aroma extract dilution analysis revealed 18 odorants that were quantified by stable isotope dilution analysis. Another important odorant, 3-methyl-1H-indole (mothball-like odor), was quantified by high-performance liquid chromatography. After storage, UFA/CLA-enriched butter showed higher concentrations of pentanal (fatty), heptanal (green), butanoic acid (cheesy), and delta-decalactone (peach-like). Photo-oxidation of butter samples induced increases in heptanal, (E)-2-octenal, and trans-4,5-epoxy-(E)-2-decenal, especially in conventional butter. The higher vitamin content in UFA/CLA samples may protect this butter from oxidation.

Basic emotions induced by odorants: a new approach based on autonomic pattern results.

PubMed

Vernet-Maury, E; Alaoui-Ismaïli, O; Dittmar, A; Delhomme, G; Chanel, J

1999-02-15

The aim of this study was to link the effects of odorants with the emotional process, through autonomic nervous system (ANS) responses. Taking Ekman's data and our previous results into account, we tried to verify a possible evocation by odorants of some basic emotions, i.e. anger, fear, sadness, surprise, disgust and happiness. The question investigated was: would it be possible to associate any of these emotions with a pattern of autonomic responses? A total of 15 subjects inhaled five odorants: lavender, ethyl aceto acetate, camphor, acetic acid and butyric acid acting as olfactory stimuli. After inhaling the odorant, subjects were requested to fill out an 11-point hedonic scale to rate its 'pleasantness' vs. 'unpleasantness'. ANS parameters monitored were skin potential and resistance, skin blood flow and temperature, instantaneous respiratory frequency and instantaneous heart rate. Simultaneous recording of these six autonomic parameters permitted the analysis of phasic responses through specific ANS patterns. An analysis of variance made it possible to differentiate among the five odorants. Two-by-two odorant comparisons for autonomic responses using Tukey's HSD multiple comparison test only permitted differentiation between 'pleasant' and 'unpleasant' odors. Camphor was differentiated from both types. For instance, long duration responses were associated with 'unpleasant' odors whereas camphor elicited intermediate responses. Taking into account each subject's preferential channel, it was possible to associate each ANS pattern with a basic emotion by means of a decision tree. The computation of subjects' responses made it possible to associate an odorant with a basic emotion, over the whole group: lavender elicited mostly 'happiness', as did, to a lesser degree ethyl aceto acetate; camphor induced either 'happiness', 'surprise' or 'sadness' according to subjects' past histories; butyric and acetic acids mainly induced negative emotions: 'anger' and 'disgust'. A high correlation was evidenced between subjects' hedonic evaluation and autonomic estimation of basic emotions. These results obtained from 15 subjects were compared to those observed in two similar experiments. These approaches showed comparable results. Thus, more than 60 subjects showed similar autonomic responses which can be transcribed into basic emotions. Thus, a multiparametric autonomic analysis allows the identification of the quality of the response, i.e. the type of basic emotion in addition to the intensity.

Inhalation Frequency Controls Reformatting of Mitral/Tufted Cell Odor Representations in the Olfactory Bulb.

PubMed

Díaz-Quesada, Marta; Youngstrom, Isaac A; Tsuno, Yusuke; Hansen, Kyle R; Economo, Michael N; Wachowiak, Matt

2018-02-28

In mammals, olfactory sensation depends on inhalation, which controls activation of sensory neurons and temporal patterning of central activity. Odor representations by mitral and tufted (MT) cells, the main output from the olfactory bulb (OB), reflect sensory input as well as excitation and inhibition from OB circuits, which may change as sniff frequency increases. To test the impact of sampling frequency on MT cell odor responses, we obtained whole-cell recordings from MT cells in anesthetized male and female mice while varying inhalation frequency via tracheotomy, allowing comparison of inhalation-linked responses across cells. We characterized frequency effects on MT cell responses during inhalation of air and odorants using inhalation pulses and also "playback" of sniffing recorded from awake mice. Inhalation-linked changes in membrane potential were well predicted across frequency from linear convolution of 1 Hz responses; and, as frequency increased, near-identical temporal responses could emerge from depolarizing, hyperpolarizing, or multiphasic MT responses. However, net excitation was not well predicted from 1 Hz responses and varied substantially across MT cells, with some cells increasing and others decreasing in spike rate. As a result, sustained odorant sampling at higher frequencies led to increasing decorrelation of the MT cell population response pattern over time. Bulk activation of sensory inputs by optogenetic stimulation affected MT cells more uniformly across frequency, suggesting that frequency-dependent decorrelation emerges from odor-specific patterns of activity in the OB network. These results suggest that sampling behavior alone can reformat early sensory representations, possibly to optimize sensory perception during repeated sampling. SIGNIFICANCE STATEMENT Olfactory sensation in mammals depends on inhalation, which increases in frequency during active sampling of olfactory stimuli. We asked how inhalation frequency can shape the neural coding of odor information by recording from projection neurons of the olfactory bulb while artificially varying odor sampling frequency in the anesthetized mouse. We found that sampling an odor at higher frequencies led to diverse changes in net responsiveness, as measured by action potential output, that were not predicted from low-frequency responses. These changes led to a reorganization of the pattern of neural activity evoked by a given odorant that occurred preferentially during sustained, high-frequency inhalation. These results point to a novel mechanism for modulating early sensory representations solely as a function of sampling behavior. Copyright © 2018 the authors 0270-6474/18/382189-18$15.00/0.

Biofiltration of Asphalt Emissions: Full-scale Operation Treating Off-gases from Polymer-modified Asphalt Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Lawrence Leslie; Apel, William Arnold; Gostomski, P. A.

2004-04-01

In response to complaints from nearby residents, a biofilter was designed, installed, and tested for treating odors in one of three odorous emission streams from an asphalt plant producing polymer-modified asphalt. Hydrogen sulfide (H2S) was determined to be the most prevalent gaseous reduced sulfur compound and was detected in the emission stream only when polymer material was being added to raw asphalt. Emission stream H2S concentrations we requite variable, ranging from 16 to approximately 30,000 ppm (v/v) and considered the likely compound contributing most to the plant's odor complaints. The biofilter was effective in controlling odor from the production processmore » and removed an overall average of 65% of the H2S during polymer addition, and for H2S concentrations less than 400 ppmv, re m oval averaged 98%. These removal efficiencies reflect data from the biofilter operating at 2.5-minute empty bed residence time in 1996 and a 6.1-minute empty bed residence time in 1997. The biofilter's bed became increasingly acidified during the plant's 1997 operating season producing a pH gradient through the bed ranging from a high of 6.6 to a low of 3.1. The bed medium moisture content remained constant at about 60% (wet weight basis), but changes were observed in the water potential: no correlation to performance was determined. Changes in the microbial community reflected the bed acidification trend, with acidophiles becoming gene rally more numerous in the bed's deeper portions and in the mid to late season when the bed was most acidified. Bed acidification did not impact the biofilter's H2S removal efficiency. Nearby residents we resurveyed and roughly half of the respondents indicated that the odor conditions had improved, one-third felt odor conditions were unchanged and the remaining 15% felt odor conditions were worse despite the fact that only one of three of the plant's odorous emission streams were treated by the biofilter. Plans are to implement biofiltration for odor control at all of the facility's emission points.« less

Identity-Specific Reward Representations in Orbitofrontal Cortex Are Modulated by Selective Devaluation

PubMed Central

Howard, James D.

2017-01-01

Goal-directed behavior is sensitive to the current value of expected outcomes. This requires independent representations of specific rewards, which have been linked to orbitofrontal cortex (OFC) function. However, the mechanisms by which the human brain updates specific goals on the fly, and translates those updates into choices, have remained unknown. Here we implemented selective devaluation of appetizing food odors in combination with pattern-based neuroimaging and a decision-making task. We found that in a hungry state, participants chose to smell high-intensity versions of two value-matched food odor rewards. After eating a meal corresponding to one of the two odors, participants switched choices toward the low intensity of the sated odor but continued to choose the high intensity of the nonsated odor. This sensory-specific behavioral effect was mirrored by pattern-based changes in fMRI signal in lateral posterior OFC, where specific reward identity representations were altered after the meal for the sated food odor but retained for the nonsated counterpart. In addition, changes in functional connectivity between the OFC and general value coding in ventromedial prefrontal cortex (vmPFC) predicted individual differences in satiety-related choice behavior. These findings demonstrate how flexible representations of specific rewards in the OFC are updated by devaluation, and how functional connections to vmPFC reflect the current value of outcomes and guide goal-directed behavior. SIGNIFICANCE STATEMENT The orbitofrontal cortex (OFC) is critical for goal-directed behavior. A recent proposal is that OFC fulfills this function by representing a variety of state and task variables (“cognitive maps”), including a conjunction of expected reward identity and value. Here we tested how identity-specific representations of food odor reward are updated by satiety. We found that fMRI pattern-based signatures of reward identity in lateral posterior OFC were modulated after selective devaluation, and that connectivity between this region and general value coding ventromedial prefrontal cortex (vmPFC) predicted choice behavior. These results provide evidence for a mechanism by which devaluation modulates a cognitive map of expected reward in OFC and thereby alters general value signals in vmPFC to guide goal-directed behavior. PMID:28159906

Prenatal and Early Postnatal Odorant Exposure Heightens Odor-Evoked Mitral Cell Responses in the Mouse Olfactory Bulb

PubMed Central

2017-01-01

Abstract Early sensory experience shapes the anatomy and function of sensory circuits. In the mouse olfactory bulb (OB), prenatal and early postnatal odorant exposure through odorized food (food/odorant pairing) not only increases the volume of activated glomeruli but also increases the number of mitral and tufted cells (M/TCs) connected to activated glomeruli. Given the importance of M/TCs in OB output and in mediating lateral inhibitory networks, increasing the number of M/TCs connected to a single glomerulus may significantly change odorant representation by increasing the total output of that glomerulus and/or by increasing the strength of lateral inhibition mediated by cells connected to the affected glomerulus. Here, we seek to understand the functional impact of this long-term odorant exposure paradigm on the population activity of mitral cells (MCs). We use viral expression of GCaMP6s to examine odor-evoked responses of MCs following prenatal and early postnatal odorant exposure to two dissimilar odorants, methyl salicylate (MS) and hexanal, which are both strong activators of glomeruli on the dorsal OB surface. Previous work suggests that odor familiarity may decrease odor-evoked MC response in rodents. However, we find that early food-based odorant exposure significantly changes MC responses in an unexpected way, resulting in broad increases in the amplitude, number, and reliability of excitatory MC responses across the dorsal OB. PMID:28955723

Natural gas odor level testing: Instruments and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberson, E.H.

1995-12-01

An odor in natural and LP gases is necessary. The statistics are overwhelming; when gas customers can smell a leak before the percentage of gas in air reaches a combustible mixture, the chances of an accident are greatly reduced. How do gas companies determine if there is sufficient odor reaching every gas customers home? Injection equipment is important. The rate and quality of odorant is important. Nevertheless, precision odorization alone does not guarantee that customers` homes always have gas with a readily detectable odor. To secure that goal, odor monitoring instruments are necessary.

Differential processing of social chemosignals obtained from potential partners in regards to gender and sexual orientation.

PubMed

Lübke, Katrin T; Hoenen, Matthias; Pause, Bettina M

2012-03-17

On an individual level, human body odors carry information about whether a person is an eligible mate. The current studies investigate if body odors also transmit information about individuals being potential partners in more general terms, namely in regards to gender and sexual orientation. In study 1, 14 gay and 14 heterosexual men were presented with body odors obtained from potential partners (gay male and heterosexual female body odors, respectively) and heterosexual male body odor as a control. In study 2, 14 lesbian and 14 heterosexual women were presented with lesbian female and heterosexual male body odors representing body odors of potential partners, and heterosexual female body odor as a control. Central nervous processing was analyzed using chemosensory event-related potentials and current source density analysis (64-channel EEG recording). Gay and heterosexual men responded with shorter P2 latencies to the body odors of their preferred sexual partners, and lesbian women responded with shorter P2 latencies to body odors of their preferred gender. In response to heterosexual male body odors, lesbian women displayed the most pronounced P3 amplitude, and distinct neuronal activation in medial frontal and parietal neocortical areas. A similar pattern of neuronal activation was observed in gay men when presented with heterosexual male body odor. Both the early processing advantage (P2) for desirable partners' body odors as well as the enhanced evaluative processing (P3, CSD) of undesirable partners' body odors suggest that human body odors indeed carry information about individuals being potential partners in terms of gender and sexual orientation. Copyright © 2011 Elsevier B.V. All rights reserved.

Descriptive epidemiology of indoor odor complaints at a large teaching institution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boswell, R.T.; DiBerardinis, L.; Ducatman, A.

1994-04-01

Investigation of indoor odor complaints consumes a substantial portion of the time and resources of many industrial hygiene offices, yet very little information has been published on the subject. We examined 3 years of data on indoor odor complaints at the Massachusetts Institute of Technology in Cambridge, Massachusetts in order to identify factors that may trigger complaints of odors. Plumbing and maintenance accounted for the majority of activities responsible for the identified sources (35% of calls), while research and teaching activities accounted for only 11 percent of calls. A larger number of calls were received during the winter months whenmore » windows are closed and school is in session. There was generally good correlation between the description of an odor by a complainant and the actual source. Offices/secretarial areas/office support rooms accounted for almost half of the calls, while laboratory facilities accounted for 19 percent of the calls. Despite the fact that the chemistry department was responsible for the most number of calls, the odor sources from these complaints were related primarily to plumbing (dried sink and floor drains) and not the chemicals used for research and teaching. Four types of abatement measures were used when odor sources could be identified: natural dissipation of the odor (23%), advice for prevention of future odors (11%), controlling an odor source (16%), and correction of the odor source (33%). We conclude that the majority of sources of indoor odors which trigger complaints are related to the maintenance of the physical plant, and that complaints are likely to be generated by unfamiliarity with certain odors. Recommendations are given to help reduce indoor odors and the time-consuming investigations into complaints from these odors. 10 refs., 4 figs.« less

Effect of fragrance use on discrimination of individual body odor.

PubMed

Allen, Caroline; Havlíček, Jan; Roberts, S Craig

2015-01-01

Previous research suggests that artificial fragrances may be chosen to complement or enhance an individual's body odor, rather than simply masking it, and that this may create an odor blend with an emergent quality that is perceptually distinguishable from body odor or fragrance alone. From this, it can be predicted that a new emergent odor might be more easily identified than an individual's body odor in isolation. We used a triangle test paradigm to assess whether fragrance affects people's ability to distinguish between individual odors. Six male and six female donors provided axillary odor samples in three conditions (without fragrance, wearing their own fragrance, and wearing an assigned fragrance). In total, 296 female and 131 male participants selected the odd one from three odor samples (two from one donor, one from another; both of the same sex). We found that participants could discriminate between the odors at above chance levels in all three odor conditions. Olfactory identification ability (measured using Sniffin' Sticks) positively predicted discrimination performance, and sex differences in performance were also observed, with female raters being correct more often than men. Success rates were also higher for odors of male donors. Additionally, while performance was above chance in all conditions, individual odor discrimination varied across the three conditions. Discrimination rate was significantly higher in the "no fragrance" condition than either of the fragranced conditions. Importantly, however, discrimination rate was also significantly higher in the "own fragrance" condition than the "assigned fragrance" condition, suggesting that naturally occurring variance in body odor is more preserved when blended with fragrances that people choose for themselves, compared with other fragrances. Our data are consistent with the idea that fragrance choices are influenced by fragrance interactions with an individual's own body odor.

Effect of fragrance use on discrimination of individual body odor

PubMed Central

Allen, Caroline; Havlíček, Jan; Roberts, S. Craig

2015-01-01

Previous research suggests that artificial fragrances may be chosen to complement or enhance an individual’s body odor, rather than simply masking it, and that this may create an odor blend with an emergent quality that is perceptually distinguishable from body odor or fragrance alone. From this, it can be predicted that a new emergent odor might be more easily identified than an individual’s body odor in isolation. We used a triangle test paradigm to assess whether fragrance affects people’s ability to distinguish between individual odors. Six male and six female donors provided axillary odor samples in three conditions (without fragrance, wearing their own fragrance, and wearing an assigned fragrance). In total, 296 female and 131 male participants selected the odd one from three odor samples (two from one donor, one from another; both of the same sex). We found that participants could discriminate between the odors at above chance levels in all three odor conditions. Olfactory identification ability (measured using Sniffin’ Sticks) positively predicted discrimination performance, and sex differences in performance were also observed, with female raters being correct more often than men. Success rates were also higher for odors of male donors. Additionally, while performance was above chance in all conditions, individual odor discrimination varied across the three conditions. Discrimination rate was significantly higher in the “no fragrance” condition than either of the fragranced conditions. Importantly, however, discrimination rate was also significantly higher in the “own fragrance” condition than the “assigned fragrance” condition, suggesting that naturally occurring variance in body odor is more preserved when blended with fragrances that people choose for themselves, compared with other fragrances. Our data are consistent with the idea that fragrance choices are influenced by fragrance interactions with an individual’s own body odor. PMID:26300812

Restrained eaters show altered brain response to food odor.

PubMed

Kemmotsu, Nobuko; Murphy, Claire

2006-02-28

Do restrained and unrestrained eaters differ in their brain response to food odor? We addressed this question by examining restrained eaters' brain response to food (chocolate) and non-food (geraniol, floral) odors, both when odor was attended to and when ignored. Using olfactory event-related potentials (OERPs), we found that restrained eaters and controls responded similarly to the non-food odor; however, unlike controls, restrained eaters showed no increase in brain response to the food odor when they focused attention on it. Rather, restrained eaters showed attenuated OERP amplitudes to the food odor in both attended and ignored conditions, suggesting that the brain's response to attended food odor was abnormally suppressed.

Cognitive Facilitation Following Intentional Odor Exposure

PubMed Central

Johnson, Andrew J.

2011-01-01

This paper reviews evidence that, in addition to incidental olfactory pollutants, intentional odor delivery can impact cognitive operations both positively and negatively. Evidence for cognitive facilitation/interference is reviewed alongside four potential explanations for odor-induced effects. It is concluded that the pharmacological properties of odors can induce changes in cognition. However, these effects can be accentuated/attenuated by the shift in mood following odor exposure, expectancy of cognitive effects, and cues to behavior via the contextual association with the odor. It is proposed that greater consideration is required in the intentional utilization of odors within both industrial and private locations, since differential effects are observed for odors with positive hedonic qualities. PMID:22163909

Robust and Rapid Air-Borne Odor Tracking without Casting1,2,3

PubMed Central

Bhattacharyya, Urvashi

2015-01-01

Abstract Casting behavior (zigzagging across an odor stream) is common in air/liquid-borne odor tracking in open fields; however, terrestrial odor localization often involves path selection in a familiar environment. To study this, we trained rats to run toward an odor source in a multi-choice olfactory arena with near-laminar airflow. We find that rather than casting, rats run directly toward an odor port, and if this is incorrect, they serially sample other sources. This behavior is consistent and accurate in the presence of perturbations, such as novel odors, background odor, unilateral nostril stitching, and turbulence. We developed a model that predicts that this run-and-scan tracking of air-borne odors is faster than casting, provided there are a small number of targets at known locations. Thus, the combination of best-guess target selection with fallback serial sampling provides a rapid and robust strategy for finding odor sources in familiar surroundings. PMID:26665165

Olfactory receptor antagonism between odorants

PubMed Central

Oka, Yuki; Omura, Masayo; Kataoka, Hiroshi; Touhara, Kazushige

2004-01-01

The detection of thousands of volatile odorants is mediated by several hundreds of different G protein-coupled olfactory receptors (ORs). The main strategy in encoding odorant identities is a combinatorial receptor code scheme in that different odorants are recognized by different sets of ORs. Despite increasing information on agonist–OR combinations, little is known about the antagonism of ORs in the mammalian olfactory system. Here we show that odorants inhibit odorant responses of OR(s), evidence of antagonism between odorants at the receptor level. The antagonism was demonstrated in a heterologous OR-expression system and in single olfactory neurons that expressed a given OR, and was also visualized at the level of the olfactory epithelium. Dual functions of odorants as an agonist and an antagonist to ORs indicate a new aspect in the receptor code determination for odorant mixtures that often give rise to novel perceptual qualities that are not present in each component. The current study also provides insight into strategies to modulate perceived odorant quality. PMID:14685265

Odor tracking in sharks is reduced under future ocean acidification conditions.

PubMed

Dixson, Danielle L; Jennings, Ashley R; Atema, Jelle; Munday, Philip L

2015-04-01

Recent studies show that ocean acidification impairs sensory functions and alters the behavior of teleost fishes. If sharks and other elasmobranchs are similarly affected, this could have significant consequences for marine ecosystems globally. Here, we show that projected future CO2 levels impair odor tracking behavior of the smooth dogfish (Mustelus canis). Adult M. canis were held for 5 days in a current-day control (405 ± 26 μatm) and mid (741 ± 22 μatm) or high CO2 (1064 ± 17 μatm) treatments consistent with the projections for the year 2100 on a 'business as usual' scenario. Both control and mid CO2 -treated individuals maintained normal odor tracking behavior, whereas high CO2 -treated sharks significantly avoided the odor cues indicative of food. Control sharks spent >60% of their time in the water stream containing the food stimulus, but this value fell below 15% in high CO2 -treated sharks. In addition, sharks treated under mid and high CO2 conditions reduced attack behavior compared to the control individuals. Our findings show that shark feeding could be affected by changes in seawater chemistry projected for the end of this century. Understanding the effects of ocean acidification on critical behaviors, such as prey tracking in large predators, can help determine the potential impacts of future ocean acidification on ecosystem function. © 2014 John Wiley & Sons Ltd.

Hot and Cold Smells: Odor-Temperature Associations across Cultures

PubMed Central

Wnuk, Ewelina; de Valk, Josje M.; Huisman, John L. A.; Majid, Asifa

2017-01-01

It is often assumed odors are associated with hot and cold temperature, since odor processing may trigger thermal sensations, such as coolness in the case of mint. It is unknown, however, whether people make consistent temperature associations for a variety of everyday odors, and, if so, what determines them. Previous work investigating the bases of cross-modal associations suggests a number of possibilities, including universal forces (e.g., perception), as well as culture-specific forces (e.g., language and cultural beliefs). In this study, we examined odor-temperature associations in three cultures—Maniq (N = 11), Thai (N = 24), and Dutch (N = 24)—who differ with respect to their cultural preoccupation with odors, their odor lexicons, and their beliefs about the relationship of odors (and odor objects) to temperature. Participants matched 15 odors to temperature by touching cups filled with hot or cold water, and described the odors in their native language. The results showed no consistent associations among the Maniq, and only a handful of consistent associations between odor and temperature among the Thai and Dutch. The consistent associations differed across the two groups, arguing against their universality. Further analysis revealed cross-modal associations could not be explained by language, but could be the result of cultural beliefs. PMID:28848482

Ventilation/odor study, field study. Final report, Volume I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duffee, R.A.; Jann, P.

1981-04-01

The results are presented of field investigations in schools, hospitals, and an office building on the relation between ventilation rate and odor within the buildings. The primary objective of the study was to determine: the reduction in ventilation rates that could be achieved in public buildings without causing adverse effects on odor; the sources of odor in public buildings; and the identity of the odorants. The variables of particular interest include: type of odor, occupant density, odorant identity and concentration, differences in impressions between occupants adapted to prevailing conditions and visitors, and the influence of temperature and humidity on bothmore » the generation and perception of common contaminants. Sensory odor measurements, chemical measurements, fresh air ventilation measurements, and acceptability evaluations via questionnaires were made. Sensory odor levels were found to be quite low in most buildings tested. A three-to-five-fold reduction in the fresh air ventilation in schools, hospitals, and office buildings can be achieved without significantly affecting perceived odor intensities or detectability. Tobacco smoking was found to be the most significant, pervasive contributor to interior odor level. Total hydrocarbon content of indoor air varies directly with ventilation rates; odor, however, does not. The complete set of reduced data are contained in Volume II. (LEW)« less

The impact of odor–reward memory on chemotaxis in larval Drosophila

PubMed Central

Schleyer, Michael; Reid, Samuel F.; Pamir, Evren; Saumweber, Timo; Paisios, Emmanouil; Davies, Alexander

2015-01-01

How do animals adaptively integrate innate with learned behavioral tendencies? We tackle this question using chemotaxis as a paradigm. Chemotaxis in the Drosophila larva largely results from a sequence of runs and oriented turns. Thus, the larvae minimally need to determine (i) how fast to run, (ii) when to initiate a turn, and (iii) where to direct a turn. We first report how odor-source intensities modulate these decisions to bring about higher levels of chemotactic performance for higher odor-source intensities during innate chemotaxis. We then examine whether the same modulations are responsible for alterations of chemotactic performance by learned odor “valence” (understood throughout as level of attractiveness). We find that run speed (i) is neither modulated by the innate nor by the learned valence of an odor. Turn rate (ii), however, is modulated by both: the higher the innate or learned valence of the odor, the less often larvae turn whenever heading toward the odor source, and the more often they turn when heading away. Likewise, turning direction (iii) is modulated concordantly by innate and learned valence: turning is biased more strongly toward the odor source when either innate or learned valence is high. Using numerical simulations, we show that a modulation of both turn rate and of turning direction is sufficient to account for the empirically found differences in preference scores across experimental conditions. Our results suggest that innate and learned valence organize adaptive olfactory search behavior by their summed effects on turn rate and turning direction, but not on run speed. This work should aid studies into the neural mechanisms by which memory impacts specific aspects of behavior. PMID:25887280

NREM2 and Sleep Spindles Are Instrumental to the Consolidation of Motor Sequence Memories

PubMed Central

Laventure, Samuel; Fogel, Stuart; Lungu, Ovidiu; Albouy, Geneviève; Sévigny-Dupont, Pénélope; Vien, Catherine; Sayour, Chadi; Carrier, Julie; Benali, Habib; Doyon, Julien

2016-01-01

Although numerous studies have convincingly demonstrated that sleep plays a critical role in motor sequence learning (MSL) consolidation, the specific contribution of the different sleep stages in this type of memory consolidation is still contentious. To probe the role of stage 2 non-REM sleep (NREM2) in this process, we used a conditioning protocol in three different groups of participants who either received an odor during initial training on a motor sequence learning task and were re-exposed to this odor during different sleep stages of the post-training night (i.e., NREM2 sleep [Cond-NREM2], REM sleep [Cond-REM], or were not conditioned during learning but exposed to the odor during NREM2 [NoCond]). Results show that the Cond-NREM2 group had significantly higher gains in performance at retest than both the Cond-REM and NoCond groups. Also, only the Cond-NREM2 group yielded significant changes in sleep spindle characteristics during cueing. Finally, we found that a change in frequency of sleep spindles during cued-memory reactivation mediated the relationship between the experimental groups and gains in performance the next day. These findings strongly suggest that cued-memory reactivation during NREM2 sleep triggers an increase in sleep spindle activity that is then related to the consolidation of motor sequence memories. PMID:27032084

Removal of target odorous molecules on to activated carbon cloths.

PubMed

Le Leuch, L M; Subrenat, A; Le Cloirec, P

2004-01-01

Activated carbon materials are adsorbents whose physico-chemical properties are interesting for the treatment of odorous compounds like hydrogen sulfide. Indeed, their structural parameters (pore structure) and surface chemistry (presence of heteroatoms such as oxygen, hydrogen, nitrogen, sulfur, phosphorus) play an important role in H2S removal. The cloth texture of these adsorbents (activated carbon cloths) is particularly adapted for dealing with high flows, often found in the treatment of odor emissions. Thus, this paper first presents the influence of these parameters through adsorption isothermal curves performed on several materials. Secondly, tests in a dynamic system are described. They highlight the low critical thickness of the fabric compared to granular activated carbon.

Elaborated Odor Test for Extended Exposure

NASA Technical Reports Server (NTRS)

Buchanan, Vanessa D.; Henry, Emily J.; Mast, Dion J.; Harper, Susana A.; Beeson, Harold D.; Tapia, Alma S.

2016-01-01

Concerns were raised when incidental exposure to a proprietary bonding material revealed the material had an irritating odor. The NASA-STD-6001B document describes a supplemental test method option for programs to evaluate materials with odor concerns (Test 6, Odor Assessment). In addition to the supplemental standard odor assessment with less than 10 seconds of exposure, the NASA White Sands Test Facility (WSTF) Materials Flight Acceptance Testing section was requested to perform an odor test with an extended duration to evaluate effects of an extended exposure and to more closely simulate realistic exposure scenarios. With approval from the NASA Johnson Space Center Industrial Hygienist, WSTF developed a 15-minute odor test method. WSTF performed this extended-duration odor test to evaluate the odor and physical effects of the bonding material configured between two aluminum plates, after the safety of the gas was verified via toxicity analysis per NASA-STD-6001B Test 7, Determination of Offgassed Products. During extended-duration testing, odor panel members were arranged near the test material in a small room with the air handlers and doors closed to minimize dilution. The odor panel members wafted gas toward themselves and recorded their individual assessments of odor and physical effects at various intervals during the 15-minute exposure and posttest. A posttest interview was conducted to obtain further information. Testing was effective in providing data for comparison and selection of an optimal offgassing and odor containment configuration. The developed test method for extended exposure is proposed as a useful tool for further evaluating materials with identified odors of concern if continued use of the material is anticipated.

Body Odor Based Personality Judgments: The Effect of Fragranced Cosmetics

PubMed Central

Sorokowska, Agnieszka; Sorokowski, Piotr; Havlíček, Jan

2016-01-01

People can accurately assess various personality traits of others based on body odor (BO) alone. Previous studies have shown that correlations between odor ratings and self-assessed personality dimensions are evident for assessments of neuroticism and dominance. Here, we tested differences between assessments based on natural body odor alone, without the use of cosmetics and assessments based on the body odor of people who were allowed to use cosmetics following their daily routine. Sixty-seven observers assessed samples of odors from 113 odor donors (each odor donor provided two samples – one with and one without cosmetic use); the donors provided their personality ratings, and the raters judged personality characteristics of the donors based on the provided odor samples. Correlations between observers’ ratings and self-rated neuroticism were stronger when raters assessed body odor in the natural body odor condition (natural BO condition; rs = 0.20) than in the cosmetics use condition (BO+cosmetics condition; rs = 0.15). Ratings of dominance significantly predicted self-assessed dominance in both conditions (rs = 0.34 for natural BO and rs = 0.21 for BO+cosmetics), whereas ratings of extraversion did not predict self-assessed extraversion in either condition. In addition, ratings of body odor attractiveness and pleasantness were significantly lower in natural BO condition than in BO+cosmetics condition, although the intensity of donors’ body odors was similar under both conditions. Our findings suggest that although olfaction seems to contribute to accurate first impression judgments of certain personality traits, cosmetic use can affect assessments of others based on body odor. PMID:27148138

Olfactory cortical adaptation facilitates detection of odors against background.

PubMed

Kadohisa, Mikiko; Wilson, Donald A

2006-03-01

Detection and discrimination of odors generally, if not always, occurs against an odorous background. On any given inhalation, olfactory receptor neurons will be activated by features of both the target odorant and features of background stimuli. To identify a target odorant against a background therefore, the olfactory system must be capable of grouping a subset of features into an odor object distinct from the background. Our previous work has suggested that rapid homosynaptic depression of afferents to the anterior piriform cortex (aPCX) contributes to both cortical odor adaptation to prolonged stimulation and habituation of simple odor-evoked behaviors. We hypothesize here that this process may also contribute to figure-ground separation of a target odorant from background stimulation. Single-unit recordings were made from both mitral/tufted cells and aPCX neurons in urethan-anesthetized rats and mice. Single-unit responses to odorant stimuli and their binary mixtures were determined. One of the odorants was randomly selected as the background and presented for 50 s. Forty seconds after the onset of the background stimulus, the second target odorant was presented, producing a binary mixture. The results suggest that mitral/tufted cells continue to respond to the background odorant and, when the target odorant is presented, had response magnitudes similar to that evoked by the binary mixture. In contrast, aPCX neurons filter out the background stimulus while maintaining responses to the target stimulus. Thus the aPCX acts as a filter driven most strongly by changing stimuli, providing a potential mechanism for olfactory figure-ground separation and selective reading of olfactory bulb output.

The medial preoptic area is necessary for sexual odor preference, but not sexual solicitation, in female Syrian hamsters

PubMed Central

Martinez, Luis A.; Petrulis, Aras

2013-01-01

Precopulatory behaviors that are preferentially directed towards opposite-sex conspecifics are critical for successful reproduction, particularly in species wherein the sexes live in isolation, such as Syrian hamsters (Mesocricetus auratus). In females, these behaviors include sexual odor preference and vaginal scent marking. The neural regulation of precopulatory behaviors is thought to involve a network of forebrain areas that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). Although MA and BNST are necessary for sexual odor preference and preferential vaginal marking to male odors, respectively, the role of MPOA in odor-guided female precopulatory behaviors is not well understood. To address this issue, female Syrian hamsters with bilateral, excitotoxic lesions of MPOA (MPOA-X) or sham lesions (SHAM) were tested for sexual odor investigation, scent marking, and lordosis. MPOA-X females did not investigate male odors more than female odors in an odor preference test, indicating that MPOA may be necessary for normal sexual odor preference in female hamsters. This loss of preference cannot be attributed to a sensory deficit, since MPOA-X females successfully discriminated male odors from female odors during an odor discrimination test. Surprisingly, no deficits in vaginal scent marking were observed in MPOA-X females, although these females did exhibit decreased overall levels of flank marking compared to SHAM females. Finally, all MPOA-X females exhibited lordosis appropriately. These results suggest that MPOA plays a critical role in the neural regulation of certain aspects of odor-guided precopulatory behaviors in female Syrian hamsters. PMID:23415835

Good morning creativity: task reactivation during sleep enhances beneficial effect of sleep on creative performance.

PubMed

Ritter, Simone M; Strick, Madelijn; Bos, Maarten W; van Baaren, Rick B; Dijksterhuis, Ap

2012-12-01

Both scientists and artists have suggested that sleep facilitates creativity, and this idea has received substantial empirical support. In the current study, we investigate whether one can actively enhance the beneficial effect of sleep on creativity by covertly reactivating the creativity task during sleep. Individuals' creative performance was compared after three different conditions: sleep-with-conditioned-odor; sleep-with-control-odor; or sleep-with-no-odor. In the evening prior to sleep, all participants were presented with a problem that required a creative solution. In the two odor conditions, a hidden scent-diffuser spread an odor while the problem was presented. In the sleep-with-conditioned-odor condition, task reactivation during sleep was induced by means of the odor that was also presented while participants were informed about the problem. In the sleep-with-control-odor condition, participants were exposed to a different odor during sleep than the one diffused during problem presentation. In the no odor condition, no odor was presented. After a night of sleep with the conditioned odor, participants were found to be: (i) more creative; and (ii) better able to select their most creative idea than participants who had been exposed to a control odor or no odor while sleeping. These findings suggest that we do not have to passively wait until we are hit by our creative muse while sleeping. Task reactivation during sleep can actively trigger creativity-related processes during sleep and thereby boost the beneficial effect of sleep on creativity. © 2012 European Sleep Research Society.

Can honey bees discriminate between floral-fragrance isomers?

PubMed

Aguiar, João Marcelo Robazzi Bignelli Valente; Roselino, Ana Carolina; Sazima, Marlies; Giurfa, Martin

2018-05-24

Many flowering plants present variable complex fragrances, which usually include different isomers of the same molecule. As fragrance is an essential cue for flower recognition by pollinators, we ask if honey bees discriminate between floral-fragrance isomers in an appetitive context. We used the olfactory conditioning of the proboscis extension response (PER), which allows training a restrained bee to an odor paired with sucrose solution. Bees were trained under an absolute (a single odorant rewarded) or a differential conditioning regime (a rewarded vs. a non-rewarded odorant) using four different pairs of isomers. One hour after training, discrimination and generalization between pairs of isomers were tested. Bees trained under absolute conditioning exhibited high generalization between isomers and discriminated only one out of four isomer pairs; after differential conditioning, they learned to differentiate between two out of four pairs of isomers but in all cases generalization responses to the non-rewarding isomer remained high. Adding an aversive taste to the non-rewarded isomer facilitated discrimination of isomers that otherwise seemed non-discriminable, but generalization remained high. Although honey bees discriminated isomers under certain conditions, they achieved the task with difficulty and tended to generalize between them, thus showing that these molecules were perceptually similar to them. We conclude that the presence of isomers within floral fragrances might not necessarily contribute to a dramatic extent to floral odor diversity. © 2018. Published by The Company of Biologists Ltd.

Influence of genotype and diet on steer performance, manure odor, and carriage of pathogenic and other fecal bacteria. III. Odorous compound production.

PubMed

Miller, D N; Berry, E D; Wells, J E; Ferrell, C L; Archibeque, S L; Freetly, H C

2006-09-01

Three beef cattle diets were assessed for their potential to produce odorous compounds from cattle feces excreted during the growing and finishing periods. Eight pens containing 51 steers of varying proportions of Brahman and MARC III genotypes were fed either a chopped bromegrass hay diet or a corn silage diet for a 119-d growing period. After the growing period, all steers were switched to the same high-corn finishing diet (high corn) and fed to a target weight of 560 kg (finishing period). Fecal slurries were prepared from a composite of fresh fecal pats collected in each pen during both periods and incubated anaerobically. In additional flasks, starch, protein, or cellulose was added to the composite fecal subsamples to determine the preferred substrates for fermentation and odorous compound production. The content and composition of the fermentation products varied both initially and during the incubation, depending on the diet fed to the steers. The corn silage and high corn feces had the greater initial content of VFA (381.0 and 524.4 micromol/g of DM, respectively) compared with the bromegrass feces (139.3 micromol/g of DM) and accumulated more VFA than the bromegrass feces during the incubation. l-Lactic acid and VFA accumulation in the high corn and corn silage feces was at the expense of starch, based on starch loss and the production of straight-chain VFA. In the bromegrass feces, accumulation of branched-chain VFA and aromatic compounds and the low starch availability indicated that the protein in the feces was the primary source for odorous compound production. Substrate additions confirmed these conclusions. We conclude that starch availability was the primary factor determining accumulation and composition of malodorous fermentation products, and when starch was unavailable, fecal microorganisms utilized protein.

Brief Report: Significant Differences in Perceived Odor Pleasantness Found in Children with ASD

ERIC Educational Resources Information Center

Hrdlicka, Michal; Vodicka, Jan; Havlovicova, Marketa; Urbanek, Tomas; Blatny, Marek; Dudova, Iva

2011-01-01

The aim of our study was to explore possible differences in estimation of odor pleasantness in children with autism spectrum disorders (ASD) compared to controls. Thirty-five patients with Asperger's syndrome and high functioning autism (mean age 10.8 [plus or minus] 3.6 years; 31 boys) were compared with 35 healthy control subjects (mean age 10.4…

Odor and odorous chemical emissions from animal buildings: Part 2. Odor emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions considering variations in seasons, animal types and olfactometry laboratories. Odor emissions from four of 14 NEAMS sites with nine barns/rooms (two dair...

Odor and odorous chemical emissions from animal buildings: Part 6.Odor activity value

USDA-ARS?s Scientific Manuscript database

There is a growing concern with air and odor emissions from agricultural facilities. A supplementary research project was conducted to complement the U.S. National Air Emissions Monitoring Study (NAEMS). The overall goal of the project was to establish odor and chemical emission factors for animal...

Necrotic enteritis challenge and high dietary sodium level affect odorant composition or emission from broilers.

PubMed

Sharma, Nishchal K; Choct, Mingan; Wu, Shu-Biao; Swick, Robert A

2018-01-01

Necrotic enteritis (NE) challenge and high dietary sodium (from sodium chloride) level on odor flux from broiler litter was investigated using 160 day-old Ross 308 male chicks randomly assigned to 4 dietary treatments with 4 replicates of 10 birds each. A 2 × 2 factorial arrangement of treatments was employed. Factors were: presence or absence of NE challenge and normal (1.6 g/kg) or high (4.0 g/kg) dietary sodium (Na) level. On d 20, odorants were collected from litter headspace with a flux hood and measured using selected ion flow tube mass spectrometry (SIFT-MS). On d 33, while challenge did not lead to higher mortality, it reduced feed intake by 5.48% (P < 0.05) and body weight gain by 9.02% (P < 0.01) and worsened FCR by 5 points (P < 0.01), indicating subclinical necrotic enteritis occurred in challenged birds. Challenge increased (P < 0.01) litter moisture and litter headspace concentrations of dimethyl sulfide (P < 0.05), propyl mercaptan (P < 0.05), total butanols (P < 0.05), acetoin (P < 0.01), skatole (P = 0.05), butyric acid (P < 0.05), and methyl amine (P < 0.05) and tended to increase concentrations of ethyl mercaptan (P = 0.07), carbon disulfide (P = 0.09), indole (P = 0.10), and formic acid (P = 0.10) compared to the unchallenged group. The birds fed a high Na diet produced higher litter moisture (P < 0.01) and higher litter headspace concentration of sulfur compounds and phenol (P < 0.01) compared to those fed a normal Na diet. In the birds fed a high Na diet, challenge increased the litter flux of some additional odorants, which included 2,3-butanedione (P < 0.05), acetic acid (P < 0.01), propionic acid (P < 0.01), isobutyric acid (P < 0.01), isovaleric acid (P < 0.01), pentanoic acid (P < 0.05), 2-butanone (P < 0.05), and 3-methyl-1-butanol (P < 0.05). These findings suggest that both a high Na diet and sub-clinical NE increase the odor nuisance potential of broiler farms. © 2017 Poultry Science Association Inc.

[Odor pollution from landfill sites and its control: a review].

PubMed

Hu, Bin; Ding, Ying; Wu, Wei-Xiang; Hu, Bei-Gang; Chen, Ying-Xu

2010-03-01

Landfill sites are the major sources of offensive odor in urban public facilities. With the progress of urbanization and the residents' demands for a higher living environment quality, the odor emission from landfill sites has become a severe pollution problem, and the odor control at landfill sites has been one of the research hotspots. This paper summarized the main components and their concentrations of the odor from landfill sites, and expatiated on the research progress in the in-situ control of the odor. The further research directions in in-situ control of the odor from landfill sites were prospected.

Subliminal smells can guide social preferences.

PubMed

Li, Wen; Moallem, Isabel; Paller, Ken A; Gottfried, Jay A

2007-12-01

It is widely accepted that unconscious processes can modulate judgments and behavior, but do such influences affect one's daily interactions with other people? Given that olfactory information has relatively direct access to cortical and subcortical emotional circuits, we tested whether the affective content of subliminal odors alters social preferences. Participants rated the likeability of neutral faces after smelling pleasant, neutral, or unpleasant odors delivered below detection thresholds. Odor affect significantly shifted likeability ratings only for those participants lacking conscious awareness of the smells, as verified by chance-level trial-by-trial performance on an odor-detection task. Across participants, the magnitude of this priming effect decreased as sensitivity for odor detection increased. In contrast, heart rate responses tracked odor valence independently of odor awareness. These results indicate that social preferences are subject to influences from odors that escape awareness, whereas the availability of conscious odor information may disrupt such effects.

Maternal prefrontal cortex activation by newborn infant odors.

PubMed

Nishitani, Shota; Kuwamoto, Saori; Takahira, Asuka; Miyamura, Tsunetake; Shinohara, Kazuyuki

2014-03-01

Mothers are attracted by infant cues of a variety of different modalities. To clarify the possible neural mechanisms underlying maternal attraction to infant odor cues, we used near-infrared spectroscopy to examine prefrontal cortex (PFC) activity during odor detection tasks in which 19 mothers and 19 nulliparous females (nonmothers) were presented with infant or adult male odors. They were instructed to make a judgment about whether they smelled an odor during each task. We estimated the PFC activity by measuring the relative oxyhemoglobin (oxyHb) concentrations. The results showed that while detecting the infant odors, bilateral PFC activities were increased in mothers but not in nonmothers. In contrast, adult male odors activated the PFC similarly in mothers and nonmothers. These findings suggest that maternal activation of the PFC in response to infant odors explains a part of the neural mechanisms for maternal attraction to infant odors.

Recollective experience in odor recognition: influences of adult age and familiarity.

PubMed

Larsson, Maria; Oberg, Christina; Bäckman, Lars

2006-01-01

We examined recollective experience in odor memory as a function of age, intention to learn, and familiarity. Young and older adults studied a set of familiar and unfamiliar odors with incidental or intentional encoding instructions. At recognition, participants indicated whether their response was based on explicit recollection (remembering), a feeling of familiarity (knowing), or guessing. The results indicated no age-related differences in the distribution of experiential responses for unfamiliar odors. By contrast, for familiar odors the young demonstrated more explicit recollection than the older adults, who produced more "know" and "guess" responses. Intention to learn was unrelated to recollective experience. In addition, the observed age differences in "remember" responses for familiar odors were eliminated when odor naming was statistically controlled. This suggests that age-related deficits in activating specific odor knowledge (i.e., odor names) play an important role for age differences in recollective experience of olfactory information.

Multi-Sensor Integration to Map Odor Distribution for the Detection of Chemical Sources.

PubMed

Gao, Xiang; Acar, Levent

2016-07-04

This paper addresses the problem of mapping odor distribution derived from a chemical source using multi-sensor integration and reasoning system design. Odor localization is the problem of finding the source of an odor or other volatile chemical. Most localization methods require a mobile vehicle to follow an odor plume along its entire path, which is time consuming and may be especially difficult in a cluttered environment. To solve both of the above challenges, this paper proposes a novel algorithm that combines data from odor and anemometer sensors, and combine sensors' data at different positions. Initially, a multi-sensor integration method, together with the path of airflow was used to map the pattern of odor particle movement. Then, more sensors are introduced at specific regions to determine the probable location of the odor source. Finally, the results of odor source location simulation and a real experiment are presented.

Human Odorant Reception in the Common Bed Bug, Cimex lectularius.

PubMed

Liu, Feng; Liu, Nannan

2015-11-02

The common bed bug Cimex lectularius is a temporary ectoparasite on humans and currently resurgent in many developed countries. The ability of bed bugs to detect human odorants in the environment is critical for their host-seeking behavior. This study deciphered the chemical basis of host detection by investigating the neuronal response of olfactory sensilla to 104 human odorants using single sensillum recording and characterized the electro-physiological responses of bed bug odorant receptors to human odorants with the Xenopus expression system. The results showed that the D type of olfactory sensilla play a predominant role in detecting the human odorants tested. Different human odorants elicited different neuronal responses with different firing frequencies and temporal dynamics. Particularly, aldehydes and alcohols are the most effective stimuli in triggering strong response while none of the carboxylic acids showed a strong stimulation. Functional characterization of two bed bug odorant receptors and co-receptors in response to human odorants revealed their specific responses to the aldehyde human odorants. Taken together, the findings of this study not only provide exciting new insights into the human odorant detection of bed bugs, but also offer valuable information for developing new reagents (attractants or repellents) for the bed bug control.

Molecular Basis of Olfactory Chemoreception in the Common Bed Bug, Cimex lectularius.

PubMed

Liu, Feng; Chen, Zhou; Liu, Nannan

2017-04-06

As one of the most notorious ectoparasites, bed bugs rely heavily on human or animal blood sources for survival, mating and reproduction. Chemoreception, mediated by the odorant receptors on the membrane of olfactory sensory neurons, plays a vital role in their host seeking and risk aversion processes. We investigated the responses of odorant receptors to a large spectrum of semiochemicals, including human odorants and plant-released volatiles and found that strong responses were sparse; aldehydes/ketones were the most efficient stimuli, while carboxylic acids and aliphatics/aromatics were comparatively less effective in eliciting responses from bed bug odorant receptors. In bed bugs, both the odorant identity and concentrations play important roles in determining the strength of these responses. The odor space constructed based on the responses from all the odorant receptors tested revealed that odorants within the same chemical group are widely dispersed while odorants from different groups are intermingled, suggesting the complexity of odorant encoding in the bed bug odorant receptors. This study provides a comprehensive picture of the olfactory coding mechanisms of bed bugs that will ultimately contribute to the design and development of novel olfactory-based strategies to reduce both the biting nuisance and disease transmission from bed bugs.

Peripheral and Central Olfactory Tuning in a Moth

PubMed Central

Ong, Rose C.

2012-01-01

Animals can be innately attracted to certain odorants. Because these attractants are particularly salient, they might be expected to induce relatively strong responses throughout the olfactory pathway, helping animals detect the most relevant odors but limiting flexibility to respond to other odors. Alternatively, specific neural wiring might link innately preferred odors to appropriate behaviors without a need for intensity biases. How nonpheromonal attractants are processed by the general olfactory system remains largely unknown. In the moth Manduca sexta, we studied this with a set of innately preferred host plant odors and other, neutral odors. Electroantennogram recordings showed that, as a population, olfactory receptor neurons (ORNs) did not respond with greater intensity to host plant odors, and further local field potential recordings showed that no specific amplification of signals induced by host plant odors occurred between the first olfactory center and the second. Moreover, when odorants were mutually diluted to elicit equally intense output from the ORNs, moths were able to learn to associate all tested odorants equally well with food reward. Together, these results suggest that, although nonpheromonal host plant odors activate broadly distributed responses, they may be linked to attractive behaviors mainly through specific wiring in the brain. PMID:22362866

Human Odorant Reception in the Common Bed Bug, Cimex lectularius

PubMed Central

Liu, Feng; Liu, Nannan

2015-01-01

The common bed bug Cimex lectularius is a temporary ectoparasite on humans and currently resurgent in many developed countries. The ability of bed bugs to detect human odorants in the environment is critical for their host-seeking behavior. This study deciphered the chemical basis of host detection by investigating the neuronal response of olfactory sensilla to 104 human odorants using single sensillum recording and characterized the electro-physiological responses of bed bug odorant receptors to human odorants with the Xenopus expression system. The results showed that the D type of olfactory sensilla play a predominant role in detecting the human odorants tested. Different human odorants elicited different neuronal responses with different firing frequencies and temporal dynamics. Particularly, aldehydes and alcohols are the most effective stimuli in triggering strong response while none of the carboxylic acids showed a strong stimulation. Functional characterization of two bed bug odorant receptors and co-receptors in response to human odorants revealed their specific responses to the aldehyde human odorants. Taken together, the findings of this study not only provide exciting new insights into the human odorant detection of bed bugs, but also offer valuable information for developing new reagents (attractants or repellents) for the bed bug control. PMID:26522967

A review on the neural bases of episodic odor memory: from laboratory-based to autobiographical approaches

PubMed Central

Saive, Anne-Lise; Royet, Jean-Pierre; Plailly, Jane

2014-01-01

Odors are powerful cues that trigger episodic memories. However, in light of the amount of behavioral data describing the characteristics of episodic odor memory, the paucity of information available on the neural substrates of this function is startling. Furthermore, the diversity of experimental paradigms complicates the identification of a generic episodic odor memory network. We conduct a systematic review of the literature depicting the current state of the neural correlates of episodic odor memory in healthy humans by placing a focus on the experimental approaches. Functional neuroimaging data are introduced by a brief characterization of the memory processes investigated. We present and discuss laboratory-based approaches, such as odor recognition and odor associative memory, and autobiographical approaches, such as the evaluation of odor familiarity and odor-evoked autobiographical memory. We then suggest the development of new laboratory-ecological approaches allowing for the controlled encoding and retrieval of specific multidimensional events that could open up new prospects for the comprehension of episodic odor memory and its neural underpinnings. While large conceptual differences distinguish experimental approaches, the overview of the functional neuroimaging findings suggests relatively stable neural correlates of episodic odor memory. PMID:25071494

Odor Perception by Dogs: Evaluating Two Training Approaches for Odor Learning of Sniffer Dogs.

PubMed

Fischer-Tenhagen, Carola; Johnen, Dorothea; Heuwieser, Wolfgang; Becker, Roland; Schallschmidt, Kristin; Nehls, Irene

2017-06-01

In this study, a standardized experimental set-up with various combinations of herbs as odor sources was designed. Two training approaches for sniffer dogs were compared; first, training with a pure reference odor, and second, training with a variety of odor mixtures with the target odor as a common denominator. The ability of the dogs to identify the target odor in a new context was tested. Six different herbs (basil, St. John's wort, dandelion, marjoram, parsley, ribwort) were chosen to produce reference materials in various mixtures with (positive) and without (negative) chamomile as the target odor source. The dogs were trained to show 1 of 2 different behaviors, 1 for the positive, and 1 for the negative sample as a yes/no task. Tests were double blind with one sample presented at a time. In both training approaches, dogs were able to detect chamomile as the target odor in any presented mixture with an average sensitivity of 72% and a specificity of 84%. Dogs trained with odor mixture containing the target odor had more correct indications in the transfer task. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Structure-odor relationships of linalool, linalyl acetate and their corresponding oxygenated derivatives

NASA Astrophysics Data System (ADS)

Elsharif, Shaimaa; Banerjee, Ashutosh; Buettner, Andrea

2015-10-01

Linalool 1 is an odorant that is commonly perceived as having a pleasant odor, but is also known to elicit physiological effects such as inducing calmness and enhancing sleep. However, no comprehensive studies are at hand to show which structural features are responsible for these prominent effects. Therefore, a total of six oxygenated derivatives were synthesized from both 1 and linalyl acetate 2, and were tested for their odor qualities and relative odor thresholds (OTs) in air. Linalool was found to be the most potent odorant among the investigated compounds, with an average OT of 3.2 ng/L, while the 8-hydroxylinalool derivative was the least odorous compound with an OT of 160 ng/L; 8-carboxylinalool was found to be odorless. The odorant 8-oxolinalyl acetate, which has very similar odor properties to linalool, was the most potent odorant besides linalool, exhibiting an OT of 5.9 ng/L. By comparison, 8-carboxylinalyl acetate had a similar OT (6.1 ng/L) as its corresponding 8-oxo derivative but exhibited divergent odor properties (fatty, greasy, musty). Overall, oxygenation on carbon 8 had a substantial effect on the aroma profiles of structural derivatives of linalool and linalyl acetate.

Identification of pleasant, neutral, and unpleasant odors in schizophrenia

PubMed Central

Kamath, Vidyulata; Turetsky, Bruce I.; Moberg, Paul J.

2010-01-01

Recent work on odor hedonics in schizophrenia has indicated that patients display abnormalities in hedonic judgments of odors in comparison to healthy comparison participants. In the current study, identification accuracy for pleasant, neutral, and unpleasant odors in individuals with schizophrenia and healthy controls was examined. Thirty-three schizophrenia patients (63% male) and thirty-one healthy volunteers (65% male) were recruited. The groups were well matched on age, sex, and smoking status. Participants were administered the University of Pennsylvania Smell Identification Test, which was subsequently divided into 16 pleasant, 15 neutral, and 9 unpleasant items. Analysis of identification z-scores for pleasant, neutral, and unpleasant odors revealed a significant diagnosis by valence interaction. Post-hoc analysis revealed that schizophrenia participants made more identification errors on pleasant and neutral odors compared to healthy controls, with no differences observed for unpleasant odors. No effect was seen for sex. The findings from the current investigation suggest that odor identification accuracy in patients is influenced by odor valence. This pattern of results parallels a growing body of literature indicating that patients display aberrant pleasantness ratings for pleasant odors and highlights the need for additional research on the influence of odor valence on olfactory identification performance in individuals with schizophrenia. PMID:21239063

A Mathematical Model of the Olfactory Bulb for the Selective Adaptation Mechanism in the Rodent Olfactory System.

PubMed

Soh, Zu; Nishikawa, Shinya; Kurita, Yuichi; Takiguchi, Noboru; Tsuji, Toshio

2016-01-01

To predict the odor quality of an odorant mixture, the interaction between odorants must be taken into account. Previously, an experiment in which mice discriminated between odorant mixtures identified a selective adaptation mechanism in the olfactory system. This paper proposes an olfactory model for odorant mixtures that can account for selective adaptation in terms of neural activity. The proposed model uses the spatial activity pattern of the mitral layer obtained from model simulations to predict the perceptual similarity between odors. Measured glomerular activity patterns are used as input to the model. The neural interaction between mitral cells and granular cells is then simulated, and a dissimilarity index between odors is defined using the activity patterns of the mitral layer. An odor set composed of three odorants is used to test the ability of the model. Simulations are performed based on the odor discrimination experiment on mice. As a result, we observe that part of the neural activity in the glomerular layer is enhanced in the mitral layer, whereas another part is suppressed. We find that the dissimilarity index strongly correlates with the odor discrimination rate of mice: r = 0.88 (p = 0.019). We conclude that our model has the ability to predict the perceptual similarity of odorant mixtures. In addition, the model also accounts for selective adaptation via the odor discrimination rate, and the enhancement and inhibition in the mitral layer may be related to this selective adaptation.

Sensitivity of Physiological Emotional Measures to Odors Depends on the Product and the Pleasantness Ranges Used

PubMed Central

Pichon, Aline M.; Coppin, Géraldine; Cayeux, Isabelle; Porcherot, Christelle; Sander, David; Delplanque, Sylvain

2015-01-01

Emotions are characterized by synchronized changes in several components of an organism. Among them, physiological variations provide energy support for the expression of approach/avoid action tendencies induced by relevant stimuli, while self-reported subjective pleasantness feelings integrate all other emotional components and are plastic. Consequently, emotional responses evoked by odors should be highly differentiated when they are linked to different functions of olfaction (e.g., avoiding environmental hazards). As this differentiation has been observed for contrasted odors (very pleasant or unpleasant), we questioned whether subjective and physiological emotional response indicators could still disentangle subtle affective variations when no clear functional distinction is made (mildly pleasant or unpleasant fragrances). Here, we compared the sensitivity of behavioral and physiological [respiration, skin conductance, facial electromyography (EMG), and heart rate] indicators in differentiating odor-elicited emotions in two situations: when a wide range of odor families was presented (e.g., fruity, animal), covering different functional meanings; or in response to a restricted range of products in one particular family (fragrances). Results show clear differences in physiological indicators to odors that display a wide range of reported pleasantness, but these differences almost entirely vanish when fragrances are used even though their subjective pleasantness still differed. Taken together, these results provide valuable information concerning the ability of classic verbal and psychophysiological measures to investigate subtle differences in emotional reactions to a restricted range of similar olfactory stimuli. PMID:26648888

Presence of Ca2+-dependent K+ channels in chemosensory cilia support a role in odor transduction.

PubMed

Delgado, Ricardo; Saavedra, M Veronica; Schmachtenberg, Oliver; Sierralta, Jimena; Bacigalupo, Juan

2003-09-01

Olfactory receptor neurons (ORNs) respond to odorants with changes in the action potential firing rate. Excitatory responses, consisting of firing increases, are mediated by a cyclic AMP cascade that leads to the activation of cationic nonselective cyclic nucleotide-gated (CNG) channels and Ca2+-dependent Cl- (ClCa) channels. This process takes place in the olfactory cilia, where all protein components of this cascade are confined. ORNs from various vertebrate species have also been shown to generate inhibitory odor responses, expressed as decreases in action potential discharges. Odor inhibition appears to rely on Ca2+-dependent K+ (KCa) channels, but the underlying transduction mechanism remains unknown. If these channels are involved in odor transduction, they are expected to be present in the olfactory cilia. We found that a specific antibody against a large conductance KCa recognized a protein of approximately 116 kDa in Western blots of purified rat olfactory ciliary membranes. Moreover, the antibody labeled ORN cilia in isolated ORNs from rat and toad (Caudiverbera caudiverbera). In addition, single-channel recordings from inside-out membrane patches excised from toad chemosensory cilia showed the presence of 4 different types of KCa channels, with unitary conductances of 210, 60, 12, and 29 and 60 pS, high K+-selectivity, and Ca2+ sensitivities in the low micromolar range. Our work demonstrates the presence of K+ channels in the ORN cilia and supports their participation in odor transduction.

The banana code-natural blend processing in the olfactory circuitry of Drosophila melanogaster.

PubMed

Schubert, Marco; Hansson, Bill S; Sachse, Silke

2014-01-01

Odor information is predominantly perceived as complex odor blends. For Drosophila melanogaster one of the most attractive blends is emitted by an over-ripe banana. To analyze how the fly's olfactory system processes natural blends we combined the experimental advantages of gas chromatography and functional imaging (GC-I). In this way, natural banana compounds were presented successively to the fly antenna in close to natural occurring concentrations. This technique allowed us to identify the active odor components, use these compounds as stimuli and measure odor-induced Ca(2+) signals in input and output neurons of the Drosophila antennal lobe (AL), the first olfactory neuropil. We demonstrate that mixture interactions of a natural blend are very rare and occur only at the AL output level resulting in a surprisingly linear blend representation. However, the information regarding single components is strongly modulated by the olfactory circuitry within the AL leading to a higher similarity between the representation of individual components and the banana blend. This observed modulation might tune the olfactory system in a way to distinctively categorize odor components and improve the detection of suitable food sources. Functional GC-I thus enables analysis of virtually any unknown natural odorant blend and its components in their relative occurring concentrations and allows characterization of neuronal responses of complete neural assemblies. This technique can be seen as a valuable complementary method to classical GC/electrophysiology techniques, and will be a highly useful tool in future investigations of insect-insect and insect-plant chemical interactions.

Olfactory cues associated with the major histocompatibility complex.

PubMed

Eggert, F; Müller-Ruchholtz, W; Ferstl, R

Besides its immunological function of self/non-self discrimination the major histocompatibility complex (MHC) has been recognized as a possible source of individual specific body odors. Dating back to speculations on the role of the extraordinary polymorphism of the MHC as background of an individual chemosensory identity and to early observations of MHC-dependent mate choice in inbred strains of mice, systematic experimental studies revealed a first evidence for H-2 related body odors in this species. Meanwhile a large number of animal studies with rodents and a series of field studies and experiments with humans have extended our knowledge of MHC-related odor signals and substantiated the hypothesis of immunogenetic associated odor types. These results suggest that the most prominent feature of the MHC, its extraordinary genetic diversity, seems in part to be selectively maintained by behavioral mechanisms which operate in contemporary natural populations. The high degree of heterozygosity found in natural populations of most species seems to be promoted by non-disease-based selection such as mating preferences and selective block of pregnancy.

Olfactory Mechanisms for Discovery of Odorants to Reduce Insect-Host Contact

PubMed Central

Clark, Jonathan T.; Ray, Anandasankar

2016-01-01

Insects have developed highly sophisticated and sensitive olfactory systems to find animal or plant hosts for feeding. Some insects vector pathogens that cause diseases in hundreds of millions of people and destroy billions of dollars of food products every year. There is great interest, therefore, in understanding how the insect olfactory system can be manipulated to reduce their contact with hosts. Here, we review recent advances in our understanding of insect olfactory detection mechanisms, which may serve as a foundation for designing insect control programs based on manipulation of their behaviors by using odorants. Because every insect species has a unique set of olfactory receptors and olfactory-mediated behaviors, we focus primarily on general principles of odor detection that potentially apply to most insects. While these mechanisms have emerged from studies on model systems for study of insect olfaction, such as Drosophila melanogaster, they provide a foundation for discovery of odorants to repel insects or reduce host-seeking behavior. PMID:27628342

Odor-context effects in free recall after a short retention interval: a new methodology for controlling adaptation.

PubMed

Isarida, Takeo; Sakai, Tetsuya; Kubota, Takayuki; Koga, Miho; Katayama, Yu; Isarida, Toshiko K

2014-04-01

The present study investigated context effects of incidental odors in free recall after a short retention interval (5 min). With a short retention interval, the results are not confounded by extraneous odors or encounters with the experimental odor and possible rehearsal during a long retention interval. A short study time condition (4 s per item), predicted not to be affected by adaptation to the odor, and a long study time condition (8 s per item) were used. Additionally, we introduced a new method for recovery from adaptation, where a dissimilar odor was briefly presented at the beginning of the retention interval, and we demonstrated the effectiveness of this technique. An incidental learning paradigm was used to prevent overshadowing from confounding the results. In three experiments, undergraduates (N = 200) incidentally studied words presented one-by-one and received a free recall test. Two pairs of odors and a third odor having different semantic-differential characteristics were selected from 14 familiar odors. One of the odors was presented during encoding, and during the test, the same odor (same-context condition) or the other odor within the pair (different-context condition) was presented. Without using a recovery-from-adaptation method, a significant odor-context effect appeared in the 4-s/item condition, but not in the 8-s/item condition. Using the recovery-from-adaptation method, context effects were found for both the 8- and the 4-s/item conditions. The size of the recovered odor-context effect did not change with study time. There were no serial position effects. Implications of the present findings are discussed.

The medial preoptic area is necessary for sexual odor preference, but not sexual solicitation, in female Syrian hamsters.

PubMed

Martinez, Luis A; Petrulis, Aras

2013-04-01

Precopulatory behaviors that are preferentially directed towards opposite-sex conspecifics are critical for successful reproduction, particularly in species wherein the sexes live in isolation, such as Syrian hamsters (Mesocricetus auratus). In females, these behaviors include sexual odor preference and vaginal scent marking. The neural regulation of precopulatory behaviors is thought to involve a network of forebrain areas that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). Although MA and BNST are necessary for sexual odor preference and preferential vaginal marking to male odors, respectively, the role of MPOA in odor-guided female precopulatory behaviors is not well understood. To address this issue, female Syrian hamsters with bilateral, excitotoxic lesions of MPOA (MPOA-X) or sham lesions (SHAM) were tested for sexual odor investigation, scent marking, and lordosis. MPOA-X females did not investigate male odors more than female odors in an odor preference test, indicating that MPOA may be necessary for normal sexual odor preference in female hamsters. This loss of preference cannot be attributed to a sensory deficit, since MPOA-X females successfully discriminated male odors from female odors during an odor discrimination test. Surprisingly, no deficits in vaginal scent marking were observed in MPOA-X females, although these females did exhibit decreased overall levels of flank marking compared to SHAM females. Finally, all MPOA-X females exhibited lordosis appropriately. These results suggest that MPOA plays a critical role in the neural regulation of certain aspects of odor-guided precopulatory behaviors in female Syrian hamsters. Copyright © 2013 Elsevier Inc. All rights reserved.

The Effects of Soil Texture on the Ability of Human Remains Detection Dogs to Detect Buried Human Remains.

PubMed

Alexander, Michael B; Hodges, Theresa K; Wescott, Daniel J; Aitkenhead-Peterson, Jacqueline A

2016-05-01

Despite technological advances, human remains detection (HRD) dogs still remain one of the best tools for locating clandestine graves. However, soil texture may affect the escape of decomposition gases and therefore the effectiveness of HDR dogs. Six nationally credentialed HRD dogs (three HRD only and three cross-trained) were evaluated on novel buried human remains in contrasting soils, a clayey and a sandy soil. Search time and accuracy were compared for the clayey soil and sandy soil to assess odor location difficulty. Sandy soil (p < 0.001) yielded significantly faster trained response times, but no significant differences were found in performance accuracy between soil textures or training method. Results indicate soil texture may be significant factor in odor detection difficulty. Prior knowledge of soil texture and moisture may be useful for search management and planning. Appropriate adjustments to search segment sizes, sweep widths and search time allotment depending on soil texture may optimize successful detection. © 2016 American Academy of Forensic Sciences.

Effect of Food Waste Co-Digestion on Digestion, Dewatering, and Cake Quality.

PubMed

Higgins, Matthew; Rajagopalan, Ganesh; Miller, Andre; Brown, Jeffrey; Beightol, Steven

2017-01-01

  The objective of this study was to evaluate the effect of food waste addition on anaerobic digestion performance as well as downstream parameters including dewatering, cake quality, and filtrate quality. Laboratory-scale digesters were fed processed food waste at rates of 25%, 45%, and 65% increased chemical oxygen demand (COD) loading rates compared to a control fed only primary and secondary solids. The specific methane yield increased from 370 L CH4/kg VSadded for the control to 410, 440, and 470 L CH4/kg VSadded for the 25, 45, and 65% food waste addition, respectively. The cake solids after dewatering were all higher for the food waste digesters compared to the control, with the highest cake solids being measured for the 45% food-waste loading. Compared to the control digester, the biosolids odorant concentration increased for the lowest dose of food waste. Odorant concentrations were below detection for the highest food waste loading.

The smell of age: perception and discrimination of body odors of different ages.

PubMed

Mitro, Susanna; Gordon, Amy R; Olsson, Mats J; Lundström, Johan N

2012-01-01

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20-30 years old), Middle-age (45-55), and Old-age (75-95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age.

The Smell of Age: Perception and Discrimination of Body Odors of Different Ages

PubMed Central

Mitro, Susanna; Gordon, Amy R.; Olsson, Mats J.; Lundström, Johan N.

2012-01-01

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20–30 years old), Middle-age (45–55), and Old-age (75–95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age. PMID:22666457

Odor and odorous chemical emissions from animal buildings: Part 2 - odor emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions. Odor emissions from two animal species (dairy and swine) from four sites with nine barns/rooms (two dairy barns in Wisconsin, two dairy barns and two sw...

Insights into structural features determining odorant affinities to honey bee odorant binding protein 14.

PubMed

Schwaighofer, Andreas; Pechlaner, Maria; Oostenbrink, Chris; Kotlowski, Caroline; Araman, Can; Mastrogiacomo, Rosa; Pelosi, Paolo; Knoll, Wolfgang; Nowak, Christoph; Larisika, Melanie

2014-04-18

Molecular interactions between odorants and odorant binding proteins (OBPs) are of major importance for understanding the principles of selectivity of OBPs towards the wide range of semiochemicals. It is largely unknown on a structural basis, how an OBP binds and discriminates between odorant molecules. Here we examine this aspect in greater detail by comparing the C-minus OBP14 of the honey bee (Apis mellifera L.) to a mutant form of the protein that comprises the third disulfide bond lacking in C-minus OBPs. Affinities of structurally analogous odorants featuring an aromatic phenol group with different side chains were assessed based on changes of the thermal stability of the protein upon odorant binding monitored by circular dichroism spectroscopy. Our results indicate a tendency that odorants show higher affinity to the wild-type OBP suggesting that the introduced rigidity in the mutant protein has a negative effect on odorant binding. Furthermore, we show that OBP14 stability is very sensitive to the position and type of functional groups in the odorant. Copyright © 2014 Elsevier Inc. All rights reserved.

Sequence Comparisons of Odorant Receptors among Tortricid Moths Reveal Different Rates of Molecular Evolution among Family Members

PubMed Central

Carraher, Colm; Authier, Astrid; Steinwender, Bernd; Newcomb, Richard D.

2012-01-01

In insects, odorant receptors detect volatile cues involved in behaviours such as mate recognition, food location and oviposition. We have investigated the evolution of three odorant receptors from five species within the moth genera Ctenopseustis and Planotrotrix, family Tortricidae, which fall into distinct clades within the odorant receptor multigene family. One receptor is the orthologue of the co-receptor Or83b, now known as Orco (OR2), and encodes the obligate ion channel subunit of the receptor complex. In comparison, the other two receptors, OR1 and OR3, are ligand-binding receptor subunits, activated by volatile compounds produced by plants - methyl salicylate and citral, respectively. Rates of sequence evolution at non-synonymous sites were significantly higher in OR1 compared with OR2 and OR3. Within the dataset OR1 contains 109 variable amino acid positions that are distributed evenly across the entire protein including transmembrane helices, loop regions and termini, while OR2 and OR3 contain 18 and 16 variable sites, respectively. OR2 shows a high level of amino acid conservation as expected due to its essential role in odour detection; however we found unexpected differences in the rate of evolution between two ligand-binding odorant receptors, OR1 and OR3. OR3 shows high sequence conservation suggestive of a conserved role in odour reception, whereas the higher rate of evolution observed in OR1, particularly at non-synonymous sites, may be suggestive of relaxed constraint, perhaps associated with the loss of an ancestral role in sex pheromone reception. PMID:22701634

Olfactory bulb gamma oscillations are enhanced with task demands.

PubMed

Beshel, Jennifer; Kopell, Nancy; Kay, Leslie M

2007-08-01

Fast oscillations in neural assemblies have been proposed as a mechanism to facilitate stimulus representation in a variety of sensory systems across animal species. In the olfactory system, intervention studies suggest that oscillations in the gamma frequency range play a role in fine odor discrimination. However, there is still no direct evidence that such oscillations are intrinsically altered in intact systems to aid in stimulus disambiguation. Here we show that gamma oscillatory power in the rat olfactory bulb during a two-alternative choice task is modulated in the intact system according to task demands with dramatic increases in gamma power during discrimination of molecularly similar odorants in contrast to dissimilar odorants. This elevation in power evolves over the course of criterion performance, is specific to the gamma frequency band (65-85 Hz), and is independent of changes in the theta or beta frequency band range. Furthermore, these high amplitude gamma oscillations are restricted to the olfactory bulb, such that concurrent piriform cortex recordings show no evidence of enhanced gamma power during these high-amplitude events. Our results display no modulation in the power of beta oscillations (15-28 Hz) shown previously to increase with odor learning in a Go/No-go task, and we suggest that the oscillatory profile of the olfactory system may be influenced by both odor discrimination demands and task type. The results reported here indicate that enhancement of local gamma power may reflect a switch in the dynamics of the system to a strategy that optimizes stimulus resolution when input signals are ambiguous.

Effect of experience with pine (Pituophis melanoleucus) and king (Lampropeltis getulus) snake odors on Y-maze behavior of pine snake hatchlings.

PubMed

Burger, J; Boarman, W; Kurzava, L; Gochfeld, M

1991-01-01

The abilities of hatchling pine snakes (Pituophis melanoleucus) and king snakes (Lampropeltis getulus) to discriminate the chemical trails of pine and king snakes was investigated inY-maze experiments. Pine snakes were housed for 17 days either with shavings impregnated with pine snake odor, king snake odor, or no odor to test for the effect of experience on choice. Both pine and king snake hatchlings entered the arm with the pine snake odor and did not enter the arm with the king snake odor. The data support the hypothesis that hatchlings of both species can distinguish conspecific odors from other odors and that our manipulation of previous experience was without effect for pine snake hatchlings.

Predicting the response of olfactory sensory neurons to odor mixtures from single odor response

NASA Astrophysics Data System (ADS)

Marasco, Addolorata; de Paris, Alessandro; Migliore, Michele

2016-04-01

The response of olfactory receptor neurons to odor mixtures is not well understood. Here, using experimental constraints, we investigate the mathematical structure of the odor response space and its consequences. The analysis suggests that the odor response space is 3-dimensional, and predicts that the dose-response curve of an odor receptor can be obtained, in most cases, from three primary components with specific properties. This opens the way to an objective procedure to obtain specific olfactory receptor responses by manipulating mixtures in a mathematically predictable manner. This result is general and applies, independently of the number of odor components, to any olfactory sensory neuron type with a response curve that can be represented as a sigmoidal function of the odor concentration.

Structure-Odor Correlations in Homologous Series of Mercapto Furans and Mercapto Thiophenes Synthesized by Changing the Structural Motifs of the Key Coffee Odorant Furan-2-ylmethanethiol.

PubMed

Schoenauer, Sebastian; Schieberle, Peter

2018-04-25

Furan-2-ylmethanethiol (2-furfurylthiol; 2-FFT, 1) is long-known as a key odorant in roast and ground coffee and was also previously identified in a wide range of thermally treated foods such as meat, bread, and roasted sesame seeds. Its unique coffee-like odor quality elicited at very low concentrations, and the fact that only a very few compounds showing a similar structure have previously been described in foods make 1 a suitable candidate for structure-odor activity studies. To gain insight into the structural features needed to evoke a coffee-like odor at low concentrations, 46 heterocyclic mercaptans and thio ethers were synthesized, 32 of them for the first time, and their odor qualities and odor thresholds were determined. A movement of the mercapto group to the 3-position kept the coffee-like aroma but led to an increase in odor threshold. A separation of the thiol group from the furan ring by an elongation of the carbon side chain caused a loss of the coffee-like odor and also led to an increase in odor thresholds, especially for ω-(furan-2-yl)alkane-1-thiols with six or seven carbon atoms in the side chain. A displacement of the furan ring by a thiophene ring had no significant influence on the odor properties of most of the compounds studied, but the newly synthesized longer-chain 1-(furan-2-yl)- and 1-(thiophene-2-yl)alkane-1-thiols elicited interesting passion fruit-like scents. In total, only 4 out of the 46 compounds also showed a coffee-like odor quality like 1, but none showed a lower odor threshold. Besides the odor attributes, also retention indices, mass spectra, and NMR data of the synthesized compounds were elaborated, which are helpful in possible future identification of these compounds in trace levels in foods or other materials.

Keeping their distance? Odor response patterns along the concentration range

PubMed Central

Strauch, Martin; Ditzen, Mathias; Galizia, C. Giovanni

2012-01-01

We investigate the interplay of odor identity and concentration coding in the antennal lobe (AL) of the honeybee Apis mellifera. In this primary olfactory center of the honeybee brain, odors are encoded by the spatio-temporal response patterns of olfactory glomeruli. With rising odor concentration, further glomerular responses are recruited into the patterns, which affects distances between the patterns. Based on calcium-imaging recordings, we found that such pattern broadening renders distances between glomerular response patterns closer to chemical distances between the corresponding odor molecules. Our results offer an explanation for the honeybee's improved odor discrimination performance at higher odor concentrations. PMID:23087621

Sensory Characterization of Odors in Used Disposable Absorbent Incontinence Products

PubMed Central

Widén, Heléne; Forsgren-Brusk, Ulla; Hall, Gunnar

2017-01-01

PURPOSE: The objectives of this study were to characterize the odors of used incontinence products by descriptive analysis and to define attributes to be used in the analysis. A further objective was to investigate to what extent the odor profiles of used incontinence products differed from each other and, if possible, to group these profiles into classes. SUBJECTS AND SETTING: Used incontinence products were collected from 14 residents with urinary incontinence living in geriatric nursing homes in the Gothenburg area, Sweden. METHODS: Pieces were cut from the wet area of used incontinence products. They were placed in glass bottles and kept frozen until odor analysis was completed. A trained panel consisting of 8 judges experienced in this area of investigation defined terminology for odor attributes. The intensities of these attributes in the used products were determined by descriptive odor analysis. Data were analyzed both by analysis of variance (ANOVA) followed by the Tukey post hoc test and by principal component analysis and cluster analysis. RESULTS: An odor wheel, with 10 descriptive attributes, was developed. The total odor intensity, and the intensities of the attributes, varied considerably between different, used incontinence products. The typical odors varied from “sweetish” to “urinal,” “ammonia,” and “smoked.” Cluster analysis showed that the used products, based on the quantitative odor data, could be divided into 5 odor classes with different profiles. CONCLUSIONS: The used products varied considerably in odor character and intensity. Findings suggest that odors in used absorptive products are caused by different types of compounds that may vary in concentration. PMID:28328646

The spatial and temporal patterns of odors sampled by lobsters and crabs in a turbulent plume.

PubMed

Reidenbach, Matthew A; Koehl, M A R

2011-09-15

Odors are dispersed across aquatic habitats by turbulent water flow as filamentous, intermittent plumes. Many crustaceans sniff (take discrete samples of ambient water and the odors it carries) by flicking their olfactory antennules. We used planar laser-induced fluorescence to investigate how flicking antennules of different morphologies (long antennules of spiny lobsters, Panulirus argus; short antennules of blue crabs, Callinectes sapidus) sample fluctuating odor signals at different positions in a turbulent odor plume in a flume to determine whether the patterns of concentrations captured can provide information about an animal's position relative to the odor source. Lobster antennules intercept odors during a greater percentage of flicks and encounter higher peak concentrations than do crab antennules, but because crabs flick at higher frequency, the duration of odor-free gaps between encountered odor pulses is similar. For flicking antennules there were longer time gaps between odor encounters as the downstream distance to the odor source decreases, but shorter gaps along the plume centerline than near the edge. In contrast to the case for antennule flicking, almost all odor-free gaps were <500 ms at all positions in the plume if concentration was measured continuously at the same height as the antennules. Variance in concentration is lower and mean concentration is greater near the substratum, where leg chemosensors continuously sample the plume, than in the water where antennules sniff. Concentrations sampled by legs increase as an animal nears an odor source, but decrease for antennules. Both legs and antennules encounter higher concentrations near the centerline than at the edge of the plume.

Pleasantness, familiarity, and identification of spice odors are interrelated and enhanced by consumption of herbs and food neophilia.

PubMed

Knaapila, Antti; Laaksonen, Oskar; Virtanen, Markus; Yang, Baoru; Lagström, Hanna; Sandell, Mari

2017-02-01

The primary dimension of odor is pleasantness, which is associated with a multitude of factors. We investigated how the pleasantness, familiarity, and identification of spice odors were associated with each other and with the use of the respective spice, overall use of herbs, and level of food neophobia. A total of 126 adults (93 women, 33 men; age 25-61 years, mean 39 years) rated the odors from 12 spices (oregano, anise, rosemary, mint, caraway, sage, thyme, cinnamon, fennel, marjoram, garlic, and clove) for pleasantness and familiarity, and completed a multiple-choice odor identification. Data on the use of specific spices, overall use of herbs, and Food Neophobia Scale score were collected using an online questionnaire. Familiar odors were mostly rated as pleasant (except garlic), whereas unfamiliar odors were rated as neutral (r = 0.63). We observed consistent and often significant trends that suggested the odor pleasantness and familiarity were positively associated with the correct odor identification, consumption of the respective spice, overall use of herbs, and food neophilia. Our results suggest that knowledge acquisition through repetitive exposure to spice odor with active attention may gradually increase the odor pleasantness within the framework set by the chemical characteristics of the aroma compound. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of pleasant, neutral, and unpleasant odors in schizophrenia.

PubMed

Kamath, Vidyulata; Turetsky, Bruce I; Moberg, Paul J

2011-05-15

Recent work on odor hedonics in schizophrenia has indicated that patients display abnormalities in hedonic judgments of odors in comparison to healthy comparison participants. In the current study, identification accuracy for pleasant, neutral, and unpleasant odors in individuals with schizophrenia and healthy controls was examined. Thirty-three schizophrenia patients (63% male) and thirty-one healthy volunteers (65% male) were recruited. The groups were well matched on age, sex, and smoking status. Participants were administered the University of Pennsylvania Smell Identification Test, which was subsequently divided into 16 pleasant, 15 neutral, and 9 unpleasant items. Analysis of identification z-scores for pleasant, neutral, and unpleasant odors revealed a significant diagnosis by valence interaction. Post-hoc analysis revealed that schizophrenia participants made more identification errors on pleasant and neutral odors compared to healthy controls, with no differences observed for unpleasant odors. No effect was seen for sex. The findings from the current investigation suggest that odor identification accuracy in patients is influenced by odor valence. This pattern of results parallels a growing body of literature indicating that patients display aberrant pleasantness ratings for pleasant odors and highlights the need for additional research on the influence of odor valence on olfactory identification performance in individuals with schizophrenia. Copyright © 2010 Elsevier Ltd. All rights reserved.

Red junglefowl have individual body odors.

PubMed

Karlsson, Anna-Carin; Jensen, Per; Elgland, Mathias; Laur, Katriann; Fyrner, Timmy; Konradsson, Peter; Laska, Matthias

2010-05-01

Olfaction may play an important role in regulating bird behavior, and has been suggested to be involved in feather-pecking. We investigated possible differences in the body odors of red junglefowl females by using an automated olfactometer which assessed the ability of trained mice to discriminate between the odors of uropygial gland secretions (the main carrier of potential individual odors in chickens) of six feather-pecked and six non-pecked birds. All mice were clearly able to discriminate between all individual red junglefowl odors, showing that each bird has an individual body odor. We analyzed whether it was more difficult to discriminate between the odors of two feather-pecked, or two non-pecked birds, than it was to discriminate between the odors of two randomly selected birds. This was not the case, suggesting that feather-pecked birds did not share a common odor signature. Analyses using gas chromatography and mass spectrometry showed that the composition of aliphatic carboxylic acids in uropygial gland secretions differed consistently between individuals. However, chemical composition did not vary according to feather-pecking status. We conclude that red junglefowl have individual body odors which appear to be largely based on differences in the relative abundance of aliphatic carboxylic acids, but there is no evidence of systematic differences between the body odors of pecked and non-pecked birds.

Molecular Basis of Olfactory Chemoreception in the Common Bed Bug, Cimex lectularius

PubMed Central

Liu, Feng; Chen, Zhou; Liu, Nannan

2017-01-01

As one of the most notorious ectoparasites, bed bugs rely heavily on human or animal blood sources for survival, mating and reproduction. Chemoreception, mediated by the odorant receptors on the membrane of olfactory sensory neurons, plays a vital role in their host seeking and risk aversion processes. We investigated the responses of odorant receptors to a large spectrum of semiochemicals, including human odorants and plant-released volatiles and found that strong responses were sparse; aldehydes/ketones were the most efficient stimuli, while carboxylic acids and aliphatics/aromatics were comparatively less effective in eliciting responses from bed bug odorant receptors. In bed bugs, both the odorant identity and concentrations play important roles in determining the strength of these responses. The odor space constructed based on the responses from all the odorant receptors tested revealed that odorants within the same chemical group are widely dispersed while odorants from different groups are intermingled, suggesting the complexity of odorant encoding in the bed bug odorant receptors. This study provides a comprehensive picture of the olfactory coding mechanisms of bed bugs that will ultimately contribute to the design and development of novel olfactory-based strategies to reduce both the biting nuisance and disease transmission from bed bugs. PMID:28383033

Health effects of indoor odorants.

PubMed Central

Cone, J E; Shusterman, D

1991-01-01

People assess the quality of the air indoors primarily on the basis of its odors and on their perception of associated health risk. The major current contributors to indoor odorants are human occupant odors (body odor), environmental tobacco smoke, volatile building materials, bio-odorants (particularly mold and animal-derived materials), air fresheners, deodorants, and perfumes. These are most often present as complex mixtures, making measurement of the total odorant problem difficult. There is no current method of measuring human body odor, other than by human panel studies of expert judges of air quality. Human body odors have been quantitated in terms of the "olf" which is the amount of air pollution produced by the average person. Another quantitative unit of odorants is the "decipol," which is the perceived level of pollution produced by the average human ventilated by 10 L/sec of unpolluted air or its equivalent level of dissatisfaction from nonhuman air pollutants. The standard regulatory approach, focusing on individual constituents or chemicals, is not likely to be successful in adequately controlling odorants in indoor air. Besides the current approach of setting minimum ventilation standards to prevent health effects due to indoor air pollution, a standard based on the olf or decipol unit might be more efficacious as well as simpler to measure. PMID:1821378

Glomerular Activity Patterns Evoked by Natural Odor Objects in the Rat Olfactory Bulb Are Related to Patterns Evoked by Major Odorant Components

PubMed Central

Johnson, Brett A.; Ong, Joan; Leon, Michael

2014-01-01

To determine how responses evoked by natural odorant mixtures compare to responses evoked by individual odorant chemicals, we mapped 2-deoxyglucose uptake during exposures to vapors arising from a variety of odor objects that may be important to rodents in the wild. We studied 21 distinct natural odor stimuli ranging from possible food sources such as fruits, vegetables, and meats to environmental odor objects such as grass, herbs, and tree leaves. The natural odor objects evoked robust and surprisingly focal patterns of 2-deoxyglucose uptake involving clusters of neighboring glomeruli, thereby resembling patterns evoked by pure chemicals. Overall, the patterns were significantly related to patterns evoked by monomolecular odorant components that had been studied previously. Object patterns also were significantly related to the molecular features present in the mixture components. Despite these overall relationships, there were individual examples of object patterns that were simpler than might have been predicted given the multiplicity of components present in the vapors. In these cases, the object patterns lacked certain responses evoked by their major odorant mixture components. These data suggest the possibility of mixture response interactions and provide a foundation for understanding the neural coding of natural odor stimuli. PMID:20187145

Age-Related Changes in Children's Hedonic Response to Male Body Odor.

ERIC Educational Resources Information Center

Stevenson, Richard J.; Repacholi, Betty M.

2003-01-01

Examined children's and adolescents' ability to identify male sweat and other odors and their rating of odors for liking. Found that only female adolescents could identify and disliked male sweat. When cued about odor identity, both male and female adolescents disliked male sweat more than children. Concluded that dislike for male sweat odor may…

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

Odor and odorous chemical emissions from animal buildings: Part 5 - Correlations between odor intensities and chemical concentrations (GC-MS/O)

USDA-ARS?s Scientific Manuscript database

Simultaneous chemical and sensory analysis based on gas chromatography-mass spectrometry-olfactometry (GC-MS-O) of air samples from livestock operations is a very useful approach for quantification of target odorous gases and also for ranking of odorous compounds. This information can help link spec...

Assessment of predation risk through conspecific alarm odors by spiny lobsters

PubMed Central

2009-01-01

Strong “alarm odors” emanating from lethally injured conspecifics may indicate an imminent risk of predation to spiny lobsters. In laboratory trials,1 strong conspecific alarm odors elicited avoidance in Panulirus argus, a highly gregarious species that displays collective defense behavior, but not in Panulirus guttatus, a species that tends to aggregate when reproductive activity is high (spring) but not when it is low (late summer) and does not display collective defensive behavior. To reduce predation risk, however, lobsters may autotomize limbs, thus sustaining nonlethal injuries. I tested the response of these lobsters to scents emanating from intact, lethally-injured and non-lethally injured conspecifics. In P. argus, these scents elicited, respectively, attraction, avoidance and a random response, suggesting that, in P. argus, avoidance of conspecific alarm odors depends on their strength. In contrast, P. guttatus lobsters responded at random to scents of lethally injured conspecifics and showed a similar response to scents of intact and non-lethally injured conspecifics in the spring (attraction) and in the summer (random), reflecting the more cryptic defensive behavior of this species. Therefore, both species use conspecific alarm odors for risk-assessment, but each responds to these cues in the most effective way to reduce its risk of predation. PMID:19721871

Extended version of the "Sniffin' Sticks" identification test: test-retest reliability and validity.

PubMed

Sorokowska, A; Albrecht, E; Haehner, A; Hummel, T

2015-03-30

The extended, 32-item version of the Sniffin' Sticks identification test was developed in order to create a precise tool enabling repeated, longitudinal testing of individual olfactory subfunctions. Odors of the previous test version had to be changed for technical reasons, and the odor identification test needed re-investigation in terms of reliability, validity, and normative values. In our study we investigated olfactory abilities of a group of 100 patients with olfactory dysfunction and 100 controls. We reconfirmed the high test-retest reliability of the extended version of the Sniffin' Sticks identification test and high correlations between the new and the original part of this tool. In addition, we confirmed the validity of the test as it discriminated clearly between controls and patients with olfactory loss. The additional set of 16 odor identification sticks can be either included in the current olfactory test, thus creating a more detailed diagnosis tool, or it can be used separately, enabling to follow olfactory function over time. Additionally, the normative values presented in our paper might provide useful guidelines for interpretation of the extended identification test results. The revised version of the Sniffin' Sticks 32-item odor identification test is a reliable and valid tool for the assessment of olfactory function. Copyright © 2015 Elsevier B.V. All rights reserved.

Different thresholds for detection and discrimination of odors in the honey bee (Apis mellifera).

PubMed

Wright, Geraldine A; Smith, Brian H

2004-02-01

Naturally occurring odors used by animals for mate recognition, food identification and other purposes must be detected at concentrations that vary across several orders of magnitude. Olfactory systems must therefore have the capacity to represent odors over a large range of concentrations regardless of dramatic changes in the salience, or perceived intensity, of a stimulus. The stability of the representation of an odor relative to other odors across concentration has not been extensively evaluated. We tested the ability of honey bees to discriminate pure odorants across a range of concentrations at and above their detection threshold. Our study showed that pure odorant compounds became progressively easier for honey bees to discriminate with increasing concentration. Discrimination is, therefore, a function of odorant concentration. We hypothesize that the recruitment of sensory cell populations across a range of concentrations may be important for odor coding, perhaps by changing its perceptual qualities or by increasing its salience against background stimuli, and that this mechanism is a general property of olfactory systems.

Sparse, decorrelated odor coding in the mushroom body enhances learned odor discrimination.

PubMed

Lin, Andrew C; Bygrave, Alexei M; de Calignon, Alix; Lee, Tzumin; Miesenböck, Gero

2014-04-01

Sparse coding may be a general strategy of neural systems for augmenting memory capacity. In Drosophila melanogaster, sparse odor coding by the Kenyon cells of the mushroom body is thought to generate a large number of precisely addressable locations for the storage of odor-specific memories. However, it remains untested how sparse coding relates to behavioral performance. Here we demonstrate that sparseness is controlled by a negative feedback circuit between Kenyon cells and the GABAergic anterior paired lateral (APL) neuron. Systematic activation and blockade of each leg of this feedback circuit showed that Kenyon cells activated APL and APL inhibited Kenyon cells. Disrupting the Kenyon cell-APL feedback loop decreased the sparseness of Kenyon cell odor responses, increased inter-odor correlations and prevented flies from learning to discriminate similar, but not dissimilar, odors. These results suggest that feedback inhibition suppresses Kenyon cell activity to maintain sparse, decorrelated odor coding and thus the odor specificity of memories.

Functional Neuronal Processing of Human Body Odors

PubMed Central

Lundström, Johan N.; Olsson, Mats J.

2013-01-01

Body odors carry informational cues of great importance for individuals across a wide range of species, and signals hidden within the body odor cocktail are known to regulate several key behaviors in animals. For a long time, the notion that humans may be among these species has been dismissed. We now know, however, that each human has a unique odor signature that carries information related to his or her genetic makeup, as well as information about personal environmental variables, such as diet and hygiene. Although a substantial number of studies have investigated the behavioral effects of body odors, only a handful have studied central processing. Recent studies have, however, demonstrated that the human brain responds to fear signals hidden within the body odor cocktail, is able to extract kin specific signals, and processes body odors differently than other perceptually similar odors. In this chapter, we provide an overview of the current knowledge of how the human brain processes body odors and the potential importance these signals have for us in everyday life. PMID:20831940

Do trained dogs discriminate individual body odors of women better than those of men?

PubMed

Jezierski, Tadeusz; Sobczyńska, Magdalena; Walczak, Marta; Gorecka-Bruzda, Aleksandra; Ensminger, John

2012-05-01

Scent identification lineups using dogs are a potentially valuable forensic tool, but have been dismissed by some critics because of cases where a false identification was shown to have occurred. It is not known, however, why dogs appear to make more false indications to the odors of some persons than of others. In this study, human genders were compared as to the degree their individual odors are distinguishable or "attractive" to dogs. Six dogs were trained to smell an individual's hand odor sample and then find the matching hand odor sample in a lineup of five odors. Using one-gender lineups and two-gender lineups with different gender ratios, it was found that dogs trained for the study identified individual women's hand odors more accurately than those of men. It is hypothesized that this is either because of differences in chemical compounds making discrimination of women's odors easier, or because of greater "odor attractiveness" of women's scents to dogs. © 2012 American Academy of Forensic Sciences.

Influence of the chemical structure on odor qualities and odor thresholds of halogenated guaiacol-derived odorants

NASA Astrophysics Data System (ADS)

Juhlke, Florian; Lorber, Katja; Wagenstaller, Maria; Buettner, Andrea

2017-12-01

Chlorinated guaiacol derivatives are found in waste water of pulp mills using chlorine in the bleaching process of wood pulp. They can also be detected in fish tissue, possibly causing off-odors. To date, there is no systematic investigation on the odor properties of halogenated guaiacol derivatives. To close this gap, odor thresholds in air and odor qualities of 14 compounds were determined by gas chromatography-olfactometry. Overall, the investigated compounds elicited smells that are characteristic for guaiacol, namely smoky, sweet, vanilla-like, but also medicinal and plaster-like. Their odor thresholds in air were, however, very low, ranging from 0.00072 to 23 ng/Lair. The lowest thresholds were found for 5-chloro- and 5-bromoguaiacol, followed by 4,5-dichloro- and 6-chloroguaiacol. Moreover, some inter-individual differences in odor threshold values could be observed, with the highest variations having been recorded for the individual values of 5-iodo- and 4-bromoguaiacol.

Odor-identity dependent motor programs underlie behavioral responses to odors

PubMed Central

Jung, Seung-Hye; Hueston, Catherine; Bhandawat, Vikas

2015-01-01

All animals use olfactory information to perform tasks essential to their survival. Odors typically activate multiple olfactory receptor neuron (ORN) classes and are therefore represented by the patterns of active ORNs. How the patterns of active ORN classes are decoded to drive behavior is under intense investigation. In this study, using Drosophila as a model system, we investigate the logic by which odors modulate locomotion. We designed a novel behavioral arena in which we could examine a fly’s locomotion under precisely controlled stimulus condition. In this arena, in response to similarly attractive odors, flies modulate their locomotion differently implying that odors have a more diverse effect on locomotion than was anticipated. Three features underlie odor-guided locomotion: First, in response to odors, flies modulate a surprisingly large number of motor parameters. Second, similarly attractive odors elicit changes in different motor programs. Third, different ORN classes modulate different subset of motor parameters. DOI: http://dx.doi.org/10.7554/eLife.11092.001 PMID:26439011

Olfactory reference syndrome: demographic and clinical features of imagined body odor.

PubMed

Phillips, Katharine A; Menard, William

2011-01-01

Olfactory reference syndrome (ORS) - preoccupation with a false belief that one emits a foul or offensive body odor - has been described around the world for more than a century. However, only a few small studies have systematically assessed ORS's clinical features. Twenty patients with ORS were systematically assessed using semistructured measures. Subjects' mean age was 33.4±14.1; 60% were female. Preoccupation most often focused on the mouth (75%), armpits (60%) and genitals (35%). Bad breath (75%) and sweat (65%) were the most common odor descriptions. Currently, 85% of subjects had delusional ORS beliefs, 77% had referential thinking and 85% reported actually smelling the odor. Ninety-five percent of subjects reported performing one or more ORS-related repetitive behaviors (e.g., excessive showering). Forty percent had been housebound for at least 1 week because of ORS symptoms, 68% had a history of suicidal ideation, 32% had attempted suicide and 53% had been psychiatrically hospitalized. Forty-four percent of subjects had sought nonpsychiatric medical, surgical or dental treatment for the perceived odor, and one third had received such treatment, which was ineffective in all cases. ORS appears to be characterized by high morbidity and seeking of nonpsychiatric treatment. Copyright © 2011 Elsevier Inc. All rights reserved.

Resolving the smell of wood - identification of odour-active compounds in Scots pine (Pinus sylvestris L.).

PubMed

Schreiner, Linda; Bauer, Patrick; Buettner, Andrea

2018-05-29

Being one of the most common trees in forests, Pinus sylvestris L. is a frequently used raw material for wood products. Its specific odour is, however, mostly unresolved to date. Accordingly, we investigated Scots pine wood samples grown in Germany for their main odorant composition. We employed dedicated odorant analysis techniques such as gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA) and successfully detected 44 odour-active compounds; of these, 39 substances were successfully identified by gas chromatography-mass spectrometry/olfactometry (GC-MS/O) and two-dimensional gas chromatography-mass spectrometry/olfactometry (2D-GC-MS/O). Among the main odorants found were (E,E)-nona-2,4-dienal, vanillin, phenylacetic acid, 3-phenylpropanoic acid, δ-octalactone and α-pinene, all of them having been detected with high flavour dilution factors during GC-O analyses. The majority of the identified odorants were fatty acid degradation products, plus some terpenoic substances and odorous substances resulting from the degradation of lignin. Although some of the detected substances have previously been reported as constituents of wood, 11 substances are reported here for the first time as odour-active compounds in wood, amongst them heptanoic acid, γ-octalactone, δ-nonalactone and (E,Z,Z)-trideca-2,4,7-trienal.

VLSI implementation of a bio-inspired olfactory spiking neural network.

PubMed

Hsieh, Hung-Yi; Tang, Kea-Tiong

2012-07-01

This paper presents a low-power, neuromorphic spiking neural network (SNN) chip that can be integrated in an electronic nose system to classify odor. The proposed SNN takes advantage of sub-threshold oscillation and onset-latency representation to reduce power consumption and chip area, providing a more distinct output for each odor input. The synaptic weights between the mitral and cortical cells are modified according to an spike-timing-dependent plasticity learning rule. During the experiment, the odor data are sampled by a commercial electronic nose (Cyranose 320) and are normalized before training and testing to ensure that the classification result is only caused by learning. Measurement results show that the circuit only consumed an average power of approximately 3.6 μW with a 1-V power supply to discriminate odor data. The SNN has either a high or low output response for a given input odor, making it easy to determine whether the circuit has made the correct decision. The measurement result of the SNN chip and some well-known algorithms (support vector machine and the K-nearest neighbor program) is compared to demonstrate the classification performance of the proposed SNN chip.The mean testing accuracy is 87.59% for the data used in this paper.

Molecular characterization and immunolocalization of the olfactory co-recepter Orco from two blood-feeding muscid flies, the stable fly (Stomoxys calcitrans, L.) and the horn fly (Haematobia irritans irritans, L.)

PubMed Central

Olafson, Pia Untalan

2012-01-01

Biting flies are economically important, blood-feeding pests of medical and veterinary significance. Chemosensory-based biting fly behaviors, such as host/nutrient source localization and ovipositional site selection, are intriguing targets for the development of supplemental control strategies. In an effort to expand our understanding of biting fly chemosensory pathways, transcripts encoding the highly conserved insect odorant co-receptor (Orco) were isolated from two representative biting fly species, the stable fly (Scal\\Orco) and the horn fly (Hirr\\Orco). Orco forms a complex with an odor-specific odorant receptor to form an odor-gated ion channel. The biting fly transcripts were predicted to encode proteins with 87% – 94% amino acid similarity to published insect Orco sequences and were detected in various immature stages as well as in adult structures associated with olfaction, i.e. antennae and maxillary palps, and gustation, i.e. proboscis. Further, the relevant proteins were immunolocalized to specific antennal sensilla using anti-serum raised against a peptide sequence conserved between the two fly species. Results from this study provide a basis for functional evaluation of repellent/attractant effects on as yet uncharacterized stable fly and horn fly conventional odorant receptors. PMID:23278866

Characterization of the Key Aroma Compounds in Proso Millet Wine Using Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry.

PubMed

Liu, Jingke; Zhao, Wei; Li, Shaohui; Zhang, Aixia; Zhang, Yuzong; Liu, Songyan

2018-02-20

The volatile compounds in proso millet wine were extracted by headspace solid-phase microextraction (85 μm polyacrylate (PA), 100 μm polydimethylsiloxane (PDMS), 75 μm Carboxen (CAR)/PDMS, and 50/30 μm divinylbenzene (DVB)/CAR/PDMS fibers), and analyzed using gas chromatography-mass spectrometry; the odor characteristics and intensities were analyzed by the odor activity value (OAV). Different sample preparation factors were used to optimize this method: sample amount, extraction time, extraction temperature, and content of NaCl. A total of 64 volatile compounds were identified from the wine sample, including 14 esters, seven alcohols, five aldehydes, five ketones, 12 benzene derivatives, 12 hydrocarbons, two terpenes, three phenols, two acids, and two heterocycles. Ethyl benzeneacetate, phenylethyl alcohol, and benzaldehyde were the main volatile compounds found in the samples. According to their OAVs, 14 volatile compounds were determined to be odor-active compounds (OAV > 1), and benzaldehyde, benzeneacetaldehyde, 1-methyl-naphthalene, 2-methyl-naphthalene, and biphenyl were the prominent odor-active compounds (OAV > 50), having a high OAV. Principal component analysis (PCA) showed the difference of distribution of the 64 volatile compounds and 14 odor-active compounds with four solid-phase microextraction (SPME) fibers.

Bio-Benchmarking of Electronic Nose Sensors

PubMed Central

Berna, Amalia Z.; Anderson, Alisha R.; Trowell, Stephen C.

2009-01-01

Background Electronic noses, E-Noses, are instruments designed to reproduce the performance of animal noses or antennae but generally they cannot match the discriminating power of the biological original and have, therefore, been of limited utility. The manner in which odorant space is sampled is a critical factor in the performance of all noses but so far it has been described in detail only for the fly antenna. Methodology Here we describe how a set of metal oxide (MOx) E-Nose sensors, which is the most commonly used type, samples odorant space and compare it with what is known about fly odorant receptors (ORs). Principal Findings Compared with a fly's odorant receptors, MOx sensors from an electronic nose are on average more narrowly tuned but much more highly correlated with each other. A set of insect ORs can therefore sample broader regions of odorant space independently and redundantly than an equivalent number of MOx sensors. The comparison also highlights some important questions about the molecular nature of fly ORs. Conclusions The comparative approach generates practical learnings that may be taken up by solid-state physicists or engineers in designing new solid-state electronic nose sensors. It also potentially deepens our understanding of the performance of the biological system. PMID:19641604

Weaker Ligands Can Dominate an Odor Blend due to Syntopic Interactions

PubMed Central

2013-01-01

Most odors in natural environments are mixtures of several compounds. Perceptually, these can blend into a new “perfume,” or some components may dominate as elements of the mixture. In order to understand such mixture interactions, it is necessary to study the events at the olfactory periphery, down to the level of single-odorant receptor cells. Does a strong ligand present at a low concentration outweigh the effect of weak ligands present at high concentrations? We used the fruit fly receptor dOr22a and a banana-like odor mixture as a model system. We show that an intermediate ligand at an intermediate concentration alone elicits the neuron’s blend response, despite the presence of both weaker ligands at higher concentration, and of better ligands at lower concentration in the mixture. Because all of these components, when given alone, elicited significant responses, this reveals specific mixture processing already at the periphery. By measuring complete dose–response curves we show that these mixture effects can be fully explained by a model of syntopic interaction at a single-receptor binding site. Our data have important implications for how odor mixtures are processed in general, and what preprocessing occurs before the information reaches the brain. PMID:23315042

Olfaction and Hearing Based Mobile Robot Navigation for Odor/Sound Source Search

PubMed Central

Song, Kai; Liu, Qi; Wang, Qi

2011-01-01

Bionic technology provides a new elicitation for mobile robot navigation since it explores the way to imitate biological senses. In the present study, the challenging problem was how to fuse different biological senses and guide distributed robots to cooperate with each other for target searching. This paper integrates smell, hearing and touch to design an odor/sound tracking multi-robot system. The olfactory robot tracks the chemical odor plume step by step through information fusion from gas sensors and airflow sensors, while two hearing robots localize the sound source by time delay estimation (TDE) and the geometrical position of microphone array. Furthermore, this paper presents a heading direction based mobile robot navigation algorithm, by which the robot can automatically and stably adjust its velocity and direction according to the deviation between the current heading direction measured by magnetoresistive sensor and the expected heading direction acquired through the odor/sound localization strategies. Simultaneously, one robot can communicate with the other robots via a wireless sensor network (WSN). Experimental results show that the olfactory robot can pinpoint the odor source within the distance of 2 m, while two hearing robots can quickly localize and track the olfactory robot in 2 min. The devised multi-robot system can achieve target search with a considerable success ratio and high stability. PMID:22319401

Trimethylamine: the substance mainly responsible for the fishy odor often associated with bacterial vaginosis.

PubMed

Brand, J M; Galask, R P

1986-11-01

The vaginal discharge of women with bacterial vaginosis often has a prominent fishy odor. Intensification of this fishy odor by the addition of strong base to the vaginal discharge suggests that it could be due to trimethylamine, the substance responsible for the characteristic odor of spoiling fish. Samples were collected from 11 women with a vaginal discharge having a fishy odor and from 10 women with no detectable odor. Gas chromatographic analysis of headspace samples of alkalinized vaginal discharges indicated the presence of trimethylamine in all 11 samples with the fishy odor but not in the other samples. The chemical identity of trimethylamine was confirmed by gas chromatography-mass spectrometry of headspace samples from two vaginal discharge samples. It is concluded that trimethylamine is the primary cause of the fishy odor associated with bacterial vaginosis.

Central insulin administration improves odor-cued reactivation of spatial memory in young men.

PubMed

Brünner, Yvonne F; Kofoet, Anja; Benedict, Christian; Freiherr, Jessica

2015-01-01

Insulin receptors are ubiquitously found in the human brain, comprising the olfactory bulb, essential for odor processing, and the hippocampus, important for spatial memory processing. The present study aimed at examining if intranasal insulin, which is known to transiently increase brain insulin levels in humans, would improve odor-cued reactivation of spatial memory in young men. We applied a double-blind, placebo-controlled, counterbalanced within-subject design. The study was conducted at the research unit of a university hospital. Interventions/Participants/Main Outcome Measures: Following intranasal administration of either insulin (40 I.U.) or placebo, male subjects (n = 18) were exposed to eight odors. During each odor exposure, a green-colored field was presented on a 17-in. computer screen. During immediate recall (comprising 3 runs), the participants were re-exposed to each odor cue, and were asked to select the corresponding field (with visual feedback after each response). The delayed recall was scheduled ∼10 min later (without feedback). To test if insulin's putative effect on odor-place memory would be domain-specific, participants also performed a separate place and odor recognition task. Intranasal insulin improved the delayed but not immediate odor-cued recall of spatial memory. This effect was independent of odor type and in the absence of systemic side effects (eg, fasting plasma glucose levels remained unaltered). Place and odor recognition were unaffected by the insulin treatment. These findings suggest that acute intranasal insulin improves odor-cued reactivation of spatial memory in young men.

Do Valenced Odors and Trait Body Odor Disgust Affect Evaluation of Emotion in Dynamic Faces?

PubMed

Syrjänen, Elmeri; Liuzza, Marco Tullio; Fischer, Håkan; Olofsson, Jonas K

2017-12-01

Disgust is a core emotion evolved to detect and avoid the ingestion of poisonous food as well as the contact with pathogens and other harmful agents. Previous research has shown that multisensory presentation of olfactory and visual information may strengthen the processing of disgust-relevant information. However, it is not known whether these findings extend to dynamic facial stimuli that changes from neutral to emotionally expressive, or if individual differences in trait body odor disgust may influence the processing of disgust-related information. In this preregistered study, we tested whether a classification of dynamic facial expressions as happy or disgusted, and an emotional evaluation of these facial expressions, would be affected by individual differences in body odor disgust sensitivity, and by exposure to a sweat-like, negatively valenced odor (valeric acid), as compared with a soap-like, positively valenced odor (lilac essence) or a no-odor control. Using Bayesian hypothesis testing, we found evidence that odors do not affect recognition of emotion in dynamic faces even when body odor disgust sensitivity was used as moderator. However, an exploratory analysis suggested that an unpleasant odor context may cause faster RTs for faces, independent of their emotional expression. Our results further our understanding of the scope and limits of odor effects on facial perception affect and suggest further studies should focus on reproducibility, specifying experimental circumstances where odor effects on facial expressions may be present versus absent.

Immunization alters body odor.

PubMed

Kimball, Bruce A; Opiekun, Maryanne; Yamazaki, Kunio; Beauchamp, Gary K

2014-04-10

Infections have been shown to alter body odor. Because immune activation accompanies both infection and immunization, we tested the hypothesis that classical immunization might similarly result in the alteration of body odors detectable by trained biosensor mice. Using a Y-maze, we trained biosensor mice to distinguish between urine odors from rabies-vaccinated (RV) and unvaccinated control mice. RV-trained mice generalized this training to mice immunized with the equine West Nile virus (WNV) vaccine compared with urine of corresponding controls. These results suggest that there are similarities between body odors of mice immunized with these two vaccines. This conclusion was reinforced when mice could not be trained to directly discriminate between urine odors of RV- versus WNV-treated mice. Next, we trained biosensor mice to discriminate the urine odors of mice treated with lipopolysaccharide (LPS; a general elicitor of innate immunological responses) from the urine of control mice. These LPS-trained biosensors could distinguish between the odors of LPS-treated mouse urine and RV-treated mouse urine. Finally, biosensor mice trained to distinguish between the odors of RV-treated mouse urine and control mouse urine did not generalize this training to discriminate between the odors of LPS-treated mouse urine and control mouse urine. From these experiments, we conclude that: (1) immunization alters urine odor in similar ways for RV and WNV immunizations; and (2) immune activation with LPS also alters urine odor but in ways different from those of RV and WNV. Published by Elsevier Inc.

Semantic networks for odors and colors in Alzheimer's disease.

PubMed

Razani, Jill; Chan, Agnes; Nordin, Steven; Murphy, Claire

2010-05-01

Impairment in odor-naming ability and in verbal and visual semantic networks raised the hypothesis of a breakdown in the semantic network for odors in Alzheimer's disease (AD). The current study addressed this hypothesis. Twenty-four individuals, half patients with probable AD and half control participants, performed triadic-similarity judgments for odors and colors, separately, which, utilizing the multidimensional scaling (MDS) technique of individual difference scaling analysis (INDSCAL), generated two-dimensional configurations of similarity. The abilities to match odors and colors with written name labels were assessed to investigate disease-related differences in ability to identify and conceptualize the stimuli. In addition, responses on attribute-sorting tasks, requiring the odor and color perceptions to be categorized as one polarity of a certain dimension, were obtained to allow for objective interpretation of the MDS spatial maps. Whereas comparison subjects generated spatial maps based predominantly on relatively abstract characteristics, patients with AD classified odors on perceptual characteristics. The maps for patients with AD also showed disorganized groupings and loose associations between odors. Their normal configurations for colors imply that the patients were able to comprehend the task per se. The data for label matching and for attribute sorting provide further evidence for a disturbance in semantic odor memory in AD. The patients performed poorer than controls on both these odor tasks, implying that the ability to identify and/or conceptualize odors is impaired in AD. The results provide clear evidence for deterioration of the structure of semantic knowledge for odors in AD.

Sensory evaluation of the synergism among odorants present in concentrations below their odor threshold in a Chinese jasmine green tea infusion.

PubMed

Ito, Yuriko; Kubota, Kikue

2005-01-01

The mechanism for the contribution of subthreshold aroma constituents to the overall jasmine tea odor impression was studied on the basis of a sensory evaluation. Binary model aqueous solutions containing the authentic odorants of a jasmine tea infusion, (E)-2-hexenyl hexanoate (I), (Z)-3-hexenol (II), and indole (III), were each prepared in a concentration below the odor threshold. Each solution had no aroma, but when 4-hexanolide replaced only 5% of each odorant, the odor intensity of each model solution was significantly strengthened. An astringent note and heavy note were recognized for each solution as the commonly perceived characteristics from the sensory evaluation. The concentration of 4-hexanolide added was also at the subthreshold level. The results suggest mutual interaction between odorants I, II, or III and 4-hexanolide. The effect on the overall odor sensation of a jasmine tea infusion by adding 4-hexanolide at a concentration below its odor threshold was also studied. In this case, the intensity of both the sweet and astringent notes was significantly strengthened in comparison with the odor impression of the original jasmine tea infusion. This phenomenon is considered to have been a synergistic effect between subthreshold odor compounds in the jasmine tea infusion. The results of this study clarify for the first time that the subthreshold aroma constituents play an important role in the characteristic flavor of a jasmine tea infusion.

Odor modeling methodology for determining the odor buffer distance for sanitary landfills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Dukman.

1991-01-01

The objective of this study is to create a methodology whereby reductions in off-site odor migrations resulting from operational and design changes in new or expanded sanitary landfills can be evaluated. The Ann Arbor Sanitary Landfill was chosen as a prototype landfill to test a hypothesis for this study. This study is a unique approach to odor prediction at sanitary landfills using surface flux measurements, odor threshold panel measurements, and dispersion modeling. Flux measurements were made at open tipping face, temporary cover, final cover, vents, and composting zones of the Ann Arbor Sanitary Landfill. Surface gas velocities and in-ground concentrationsmore » were determined to allow a quantification of the total and methane gas flow rate. Odor threshold panel measurements were performed to determine the odor intensity in odor units at the corresponding sites. The used the flux and odor panel measurements in the Industrial Source Complex Terrain Model to determine the hourly averaged highest and second highest odor levels at 175 receptors placed at the property boundary and 25 nearby residential locations. Using measured values for velocity, subsurface CH{sub 4} concentration and odor intensity, it was determined that the proposed 1990 operations with a buffer distance of 600 feet provided at least a factor of five protection below 1 o.u. of the odor threshold for all receptors, and dilution protection equal to the historic 1984 operations with a 1,200 feet isolation distance.« less

Quantitative method to determine the regional drinking water odorant regulation goals based on odor sensitivity distribution: illustrated using 2-MIB.

PubMed

Yu, Jianwei; An, Wei; Cao, Nan; Yang, Min; Gu, Junong; Zhang, Dong; Lu, Ning

2014-07-01

Taste and odor (T/O) in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward T/O. This study proposed a method to determine the regional drinking water odorant regulation goals (ORGs) based on the odor sensitivity distribution of the local population. The distribution of odor sensitivity to 2-methylisoborneol (2-MIB) by the local population in Beijing, China was revealed by using a normal distribution function/model to describe the odor complaint response to a 2-MIB episode in 2005, and a 2-MIB concentration of 12.9 ng/L and FPA (flavor profile analysis) intensity of 2.5 was found to be the critical point to cause odor complaints. Thus the Beijing ORG for 2-MIB was determined to be 12.9 ng/L. Based on the assumption that the local FPA panel can represent the local population in terms of sensitivity to odor, and that the critical FPA intensity causing odor complaints was 2.5, this study tried to determine the ORGs for seven other cities of China by performing FPA tests using an FPA panel from the corresponding city. ORG values between 12.9 and 31.6 ng/L were determined, showing that a unified ORG may not be suitable for drinking water odor regulations. This study presents a novel approach for setting drinking water odor regulations. Copyright © 2014. Published by Elsevier B.V.

Complex Odor from Plants under Attack: Herbivore's Enemies React to the Whole, Not Its Parts

PubMed Central

van Wijk, Michiel; de Bruijn, Paulien J. A.; Sabelis, Maurice W.

2011-01-01

Background Insect herbivory induces plant odors that attract herbivores' natural enemies. Assuming this attraction emerges from individual compounds, genetic control over odor emission of crops may provide a rationale for manipulating the distribution of predators used for pest control. However, studies on odor perception in vertebrates and invertebrates suggest that olfactory information processing of mixtures results in odor percepts that are a synthetic whole and not a set of components that could function as recognizable individual attractants. Here, we ask if predators respond to herbivore-induced attractants in odor mixtures or to odor mixture as a whole. Methodology/Principal Findings We studied a system consisting of Lima bean, the herbivorous mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. We found that four herbivore-induced bean volatiles are not attractive in pure form while a fifth, methyl salicylate (MeSA), is. Several reduced mixtures deficient in one component compared to the full spider-mite induced blend were not attractive despite the presence of MeSA indicating that the predators cannot detect this component in these odor mixtures. A mixture of all five HIPV is most attractive, when offered together with the non-induced odor of Lima bean. Odors that elicit no response in their pure form were essential components of the attractive mixture. Conclusions/Significance We conclude that the predatory mites perceive odors as a synthetic whole and that the hypothesis that predatory mites recognize attractive HIPV in odor mixtures is unsupported. PMID:21765908

Epac Activation Initiates Associative Odor Preference Memories in the Rat Pup

ERIC Educational Resources Information Center

Grimes, Matthew T.; Powell, Maria; Gutierrez, Sandra Mohammed; Darby-King, Andrea; Harley, Carolyn W.; McLean, John H.

2015-01-01

Here we examine the role of the exchange protein directly activated by cAMP (Epac) in ß-adrenergic-dependent associative odor preference learning in rat pups. Bulbar Epac agonist (8-pCPT-2-O-Me-cAMP, or 8-pCPT) infusions, paired with odor, initiated preference learning, which was selective for the paired odor. Interestingly, pairing odor with Epac…

[Specific odor component produced by Mycobacterium lepraemurium on Ogawa yolk medium].

PubMed

Mori, T; Aishima, T

1992-11-01

When Mycobacterium lepraemurium is grown on the 1% Ogawa yolk medium, it produces a specific odor. This odor was not observed in other easily cultivable acid-fast bacilli. Therefore, identification of the components responsible for the specific odor produced by M. lepraemurium was attempted. The odor components were extracted for overnight with sterilized and distilled water from the Ogawa yolk medium on which M. lepraemurium had been cultivated for two months. The odor components in the extract was adsorbed on refined charcoal. After washing with distilled water for three times, the charcoal was dried. Then the odor components were eluted from the charcoal with ethanol and the eluate was condensed under nitrogen gas flow at 40 degrees C. The condensate was analyzed by Gas-Chromatography-Mass-Spectrum (GC-MS). Phenylethanol and phenylacetic acid were identified as major odor components. A mixture of authentic phenylacetic acid, its methyl and ethyl esters, smelled similar to the odor of cultivated medium of M. lepraemurium. Thus, phenylacetic acid was identified as the key odor component produced by M. lepraemurium. When initial isolation culture of M. lepraemurium from murine leproma was cultivated on the Ogawa yolk medium by adding phenylacetic acid, growth inhibition was brought by the compound.

Food odors trigger an endocrine response that affects food ingestion and metabolism.

PubMed

Lushchak, Oleh V; Carlsson, Mikael A; Nässel, Dick R

2015-08-01

Food odors stimulate appetite and innate food-seeking behavior in hungry animals. The smell of food also induces salivation and release of gastric acid and insulin. Conversely, sustained odor exposure may induce satiation. We demonstrate novel effects of food odors on food ingestion, metabolism and endocrine signaling in Drosophila melanogaster. Acute exposure to attractive vinegar odor triggers a rapid and transient increase in circulating glucose, and a rapid upregulation of genes encoding the glucagon-like hormone adipokinetic hormone (AKH), four insulin-like peptides (DILPs) and some target genes in peripheral tissues. Sustained exposure to food odors, however, decreases food intake. Hunger-induced strengthening of synaptic signaling from olfactory sensory neurons (OSNs) to brain neurons increases food-seeking behavior, and conversely fed flies display reduced food odor sensitivity and feeding. We show that increasing the strength of OSN signaling chronically by genetic manipulation of local peptide neuromodulation reduces feeding, elevates carbohydrates and diminishes lipids. Furthermore, constitutively strengthened odor sensitivity altered gene transcripts for AKH, DILPs and some of their targets. Thus, we show that food odor can induce a transient anticipatory endocrine response, and that boosted sensitivity to this odor affects food intake, as well as metabolism and hormonal signaling.

A Sensory 3D Map of the Odor Description Space Derived from a Comparison of Numeric Odor Profile Databases.

PubMed

Zarzo, Manuel

2015-06-01

Many authors have proposed different schemes of odor classification, which are useful to aid the complex task of describing smells. However, reaching a consensus on a particular classification seems difficult because our psychophysical space of odor description is a continuum and is not clustered into well-defined categories. An alternative approach is to describe the perceptual space of odors as a low-dimensional coordinate system. This idea was first proposed by Crocker and Henderson in 1927, who suggested using numeric profiles based on 4 dimensions: "fragrant," "acid," "burnt," and "caprylic." In the present work, the odor profiles of 144 aroma chemicals were compared by means of statistical regression with comparable numeric odor profiles obtained from 2 databases, enabling a plausible interpretation of the 4 dimensions. Based on the results and taking into account comparable 2D sensory maps of odor descriptors from the literature, a 3D sensory map (odor cube) has been drawn up to improve understanding of the similarities and dissimilarities of the odor descriptors most frequently used in fragrance chemistry. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of Breast Milk and Vanilla Odors on Premature Neonate's Heart Rate and Blood Oxygen Saturation During and After Venipuncture.

PubMed

Neshat, Hanieh; Jebreili, Mahnaz; Seyyedrasouli, Aleheh; Ghojazade, Morteza; Hosseini, Mohammad Bagher; Hamishehkar, Hamed

2016-06-01

Different studies have shown that the use of olfactory stimuli during painful medical procedures reduces infants' response to pain. The main purpose of the current study was to investigate the effect of breast milk odor and vanilla odor on premature infants' vital signs including heart rate and blood oxygen saturation during and after venipuncture. A total of 135 preterm infants were randomly selected and divided into three groups of control, vanilla odor, and breast milk odor. Infants in the breast milk group and the vanilla group were exposed to breast milk odor and vanilla odor from 5 minutes prior to sampling until 30 seconds after sampling. The results showed that breast milk odor has a significant effect on the changes of neonatal heart rate and blood oxygen saturation during and after venipuncture and decreased the variability of premature infants' heart rate and blood oxygen saturation. Vanilla odor has no significant effect on premature infants' heart rate and blood oxygen saturation. Breast milk odor can decrease the variability of premature infants' heart rate and blood oxygen saturation during and after venipuncture. Copyright © 2015. Published by Elsevier B.V.

Left Posterior Orbitofrontal Cortex Is Associated With Odor-Induced Autobiographical Memory: An fMRI Study.

PubMed

Watanabe, Keiko; Masaoka, Yuri; Kawamura, Mitsuru; Yoshida, Masaki; Koiwa, Nobuyoshi; Yoshikawa, Akira; Kubota, Satomi; Ida, Masahiro; Ono, Kenjiro; Izumizaki, Masahiko

2018-01-01

Autobiographical odor memory (AM-odor) accompanied by a sense of realism of a specific memory elicits strong emotions. AM-odor differs from memory triggered by other sensory modalities, possibly because olfaction involves a unique sensory process. Here, we examined the orbitofrontal cortex (OFC), using functional magnetic resonance imaging (fMRI) to determine which OFC subregions are related to AM-odor. Both AM-odor and a control odor successively increased subjective ratings of comfortableness and pleasantness. Importantly, AM-odor also increased arousal levels and the vividness of memories, and was associated with a deep and slow breathing pattern. fMRI analysis indicated robust activation in the left posterior OFC (L-POFC). Connectivity between the POFC and whole brain regions was estimated using psychophysiological interaction analysis (PPI). We detected several trends in connectivity between L-POFC and bilateral precuneus, bilateral rostral dorsal anterior cingulate cortex (rdACC), and left parahippocampus, which will be useful for targeting our hypotheses for future investigations. The slow breathing observed in AM-odor was correlated with rdACC activation. Odor associated with emotionally significant autobiographical memories was accompanied by slow and deep breathing, possibly involving rdACC processing.

Direct nuclear magnetic resonance observation of odorant binding to mouse odorant receptor MOR244-3.

PubMed

Burger, Jessica L; Jeerage, Kavita M; Bruno, Thomas J

2016-06-01

Mammals are able to perceive and differentiate a great number of structurally diverse odorants through the odorant's interaction with odorant receptors (ORs), proteins found within the cell membrane of olfactory sensory neurons. The natural gas industry has used human olfactory sensitivity to sulfur compounds (thiols, sulfides, etc.) to increase the safety of fuel gas transport, storage, and use through the odorization of this product. In the United States, mixtures of sulfur compounds are used, but the major constituent of odorant packages is 2-methylpropane-2-thiol, also known as tert-butyl mercaptan. It has been fundamentally challenging to understand olfaction and odorization due to the low affinity of odorous ligands to the ORs and the difficulty in expressing a sufficient number of OR proteins. Here, we directly observed the binding of tert-butyl mercaptan and another odiferous compound, cis-cyclooctene, to mouse OR MOR244-3 on living cells by saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy. This effort lays the groundwork for resolving molecular mechanisms responsible for ligand binding and resulting signaling, which in turn will lead to a clearer understanding of odorant recognition and competition. Published by Elsevier Inc.

Molecular receptive range variation among mouse odorant receptors for aliphatic carboxylic acids

PubMed Central

Repicky, Sarah E.; Luetje, Charles W.

2009-01-01

The ability of mammals to identify and distinguish among many thousands of different odorants suggests a combinatorial use of odorant receptors, with each receptor detecting multiple odorants and each odorant interacting with multiple receptors. Numerous receptors may be devoted to the sampling of particularly important regions of odor space. Here we explore the similarities and differences in the molecular receptive ranges of four mouse odorant receptors (MOR23-1, MOR31-4, MOR32-11 and MOR40-4), which have previously been identified as receptors for aliphatic carboxylic acids. Each receptor was expressed in Xenopus oocytes, along with Gαolf and the cystic fibrosis transmembrane regulator to allow electrophysiological assay of receptor responses. We find that even though these receptors are relatively unrelated, there is extensive overlap among their receptive ranges. That is, these receptors sample a similar region of odor space. However, the receptive range of each receptor is unique. Thus, these receptors contribute to the depth of coverage of this small region of odor space. Such a group of receptors with overlapping, but distinct receptive ranges, may participate in making fine distinctions among complex mixtures of closely related odorant compounds. PMID:19166503

Olfactory systems and neural circuits that modulate predator odor fear

PubMed Central

Takahashi, Lorey K.

2014-01-01

When prey animals detect the odor of a predator a constellation of fear-related autonomic, endocrine, and behavioral responses rapidly occur to facilitate survival. How olfactory sensory systems process predator odor and channel that information to specific brain circuits is a fundamental issue that is not clearly understood. However, research in the last 15 years has begun to identify some of the essential features of the sensory detection systems and brain structures that underlie predator odor fear. For instance, the main (MOS) and accessory olfactory systems (AOS) detect predator odors and different types of predator odors are sensed by specific receptors located in either the MOS or AOS. However, complex predator chemosignals may be processed by both the MOS and AOS, which complicate our understanding of the specific neural circuits connected directly and indirectly from the MOS and AOS to activate the physiological and behavioral components of unconditioned and conditioned fear. Studies indicate that brain structures including the dorsal periaqueductal gray (DPAG), paraventricular nucleus (PVN) of the hypothalamus, and the medial amygdala (MeA) appear to be broadly involved in predator odor induced autonomic activity and hypothalamic-pituitary-adrenal (HPA) stress hormone secretion. The MeA also plays a key role in predator odor unconditioned fear behavior and retrieval of contextual fear memory associated with prior predator odor experiences. Other neural structures including the bed nucleus of the stria terminalis and the ventral hippocampus (VHC) appear prominently involved in predator odor fear behavior. The basolateral amygdala (BLA), medial hypothalamic nuclei, and medial prefrontal cortex (mPFC) are also activated by some but not all predator odors. Future research that characterizes how distinct predator odors are uniquely processed in olfactory systems and neural circuits will provide significant insights into the differences of how diverse predator odors activate fear. PMID:24653685

Olfactory systems and neural circuits that modulate predator odor fear.

PubMed

Takahashi, Lorey K

2014-01-01

When prey animals detect the odor of a predator a constellation of fear-related autonomic, endocrine, and behavioral responses rapidly occur to facilitate survival. How olfactory sensory systems process predator odor and channel that information to specific brain circuits is a fundamental issue that is not clearly understood. However, research in the last 15 years has begun to identify some of the essential features of the sensory detection systems and brain structures that underlie predator odor fear. For instance, the main (MOS) and accessory olfactory systems (AOS) detect predator odors and different types of predator odors are sensed by specific receptors located in either the MOS or AOS. However, complex predator chemosignals may be processed by both the MOS and AOS, which complicate our understanding of the specific neural circuits connected directly and indirectly from the MOS and AOS to activate the physiological and behavioral components of unconditioned and conditioned fear. Studies indicate that brain structures including the dorsal periaqueductal gray (DPAG), paraventricular nucleus (PVN) of the hypothalamus, and the medial amygdala (MeA) appear to be broadly involved in predator odor induced autonomic activity and hypothalamic-pituitary-adrenal (HPA) stress hormone secretion. The MeA also plays a key role in predator odor unconditioned fear behavior and retrieval of contextual fear memory associated with prior predator odor experiences. Other neural structures including the bed nucleus of the stria terminalis and the ventral hippocampus (VHC) appear prominently involved in predator odor fear behavior. The basolateral amygdala (BLA), medial hypothalamic nuclei, and medial prefrontal cortex (mPFC) are also activated by some but not all predator odors. Future research that characterizes how distinct predator odors are uniquely processed in olfactory systems and neural circuits will provide significant insights into the differences of how diverse predator odors activate fear.

Preliminary analysis of odor legal solutions and study on their implementation possibilities in Poland

NASA Astrophysics Data System (ADS)

Sówka, Izabela; Karski, Leszek

2018-01-01

The problem of odor nuisance requires undertaking legal means that aim towards implementation of regulations in order to improve the odor-related quality of air in selected areas in Poland. So far the works carried out in the country were concluded by drawing up `The guidelines for the bill on counteracting the odor nuisance'. However, as a result of completed social consultations in Poland, the Ministry of Environment, in 2015, resigned from implementing of so called anti-odor act. Currently, the legislature is taking steps which aim at undertaking specific actions in order to introduce solutions, which would directly regulate the issues of odors and the odor nuisance, to the national system. In the countries of the European Union, the issues related to odors are solved in diversified ways and the system still lacks of a uniform proposition, among others related to odor standards. In connection with the above, actions that are taken on a national level should fundamentally aim at developing national odor standards which would take into account the type / the kind of economic activity being a source of odor emission (e.g. clearly separated for existing objects and planned investments), at establishing a procedure and also legal and operational requirements related to determination and the types of zones with defined values of acceptable concentration and determination of reference methodology in monitoring, and modeling the dispersion of odors e.g. including strictly defined frequency of necessary tests. In addition, the process should be accompanied by a creation of financial mechanisms and streams in range of investments related to the development of technology and methods used to limit emission of odors.

The bed nucleus of the stria terminalis is critical for sexual solicitation, but not for opposite-sex odor preference, in female Syrian hamsters.

PubMed

Martinez, Luis A; Petrulis, Aras

2011-11-01

Successful reproduction in vertebrates depends critically upon a suite of precopulatory behaviors that occur prior to mating. In Syrian hamsters (Mesocricetus auratus), these behaviors include vaginal scent marking and preferential investigation of male odors. The neural regulation of vaginal marking and opposite-sex odor preference likely involves an interconnected set of steroid-sensitive nuclei that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). For example, lesions of MA eliminate opposite-sex odor preference and reduce overall levels of vaginal marking, whereas lesions of MPOA decrease vaginal marking in response to male odors. Although BNST is densely interconnected with both MA and MPOA, little is known about the role of BNST in female precopulatory behaviors. To address this question, females received either bilateral, excitotoxic lesions of BNST (BNST-X) or sham lesions (SHAM), and were tested for scent marking and for investigatory responses to male and female odors. Whereas SHAM females vaginal marked more to male odors than female odors on two days of the estrous cycle, BNST-X females marked at equivalent levels to both odors. This deficit is not due to alterations in social odor investigation, as both BNST-X and SHAM females investigated male odors more than female odors. Finally, BNST lesions did not generally disrupt the cyclic changes in reproductive behaviors that occur across the estrous cycle. Taken together, these results demonstrate that BNST is critical for the normal expression of solicitational behaviors by females in response to male odor stimuli. Copyright © 2011 Elsevier Inc. All rights reserved.

The bed nucleus of the stria terminalis is critical for sexual solicitation, but not for opposite-sex odor preference, in female Syrian hamsters

PubMed Central

Martinez, Luis A.; Petrulis, Aras

2011-01-01

Successful reproduction in vertebrates depends critically upon a suite of precopulatory behaviors that occur prior to mating. In Syrian hamsters (Mesocricetus auratus), these behaviors include vaginal scent marking and preferential investigation of male odors. The neural regulation of vaginal marking and opposite-sex odor preference likely involves an interconnected set of steroid-sensitive nuclei that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). For example, lesions of MA eliminate opposite-sex odor preference and reduce overall levels of vaginal marking, whereas lesions of MPOA decrease vaginal marking in response to male odors. Although BNST is densely interconnected with both MA and MPOA, little is known about the role of BNST in female precopulatory behaviors. To address this question, females received either bilateral, excitotoxic lesions of BNST (BNST-X) or sham lesions (SHAM), and were tested for scent marking and for investigatory responses to male and female odors. Whereas SHAM females vaginal marked more to male odors than female odors on two days of the estrous cycle, BNST-X females marked at equivalent levels to both odors. This deficit is not due to alterations in social odor investigation, as both BNST-X and SHAM females investigated male odors more than female odors. Finally, BNST lesions did not generally disrupt the cyclic changes in reproductive behaviors that occur across the estrous cycle. Taken together, these results demonstrate that BNST is critical for the normal expression of solicitational behaviors by females in response to male odor stimuli. PMID:21925504

Altered olfactory processing of stress-related body odors and artificial odors in patients with panic disorder.

PubMed

Wintermann, Gloria-Beatrice; Donix, Markus; Joraschky, Peter; Gerber, Johannes; Petrowski, Katja

2013-01-01

Patients with Panic Disorder (PD) direct their attention towards potential threat, followed by panic attacks, and increased sweat production. Onés own anxiety sweat odor influences the attentional focus, and discrimination of threat or non-threat. Since olfactory projection areas overlap with neuronal areas of a panic-specific fear network, the present study investigated the neuronal processing of odors in general and of stress-related sweat odors in particular in patients with PD. A sample of 13 patients with PD with/ without agoraphobia and 13 age- and gender-matched healthy controls underwent an fMRI investigation during olfactory stimulation with their stress-related sweat odors (TSST, ergometry) as well as artificial odors (peach, artificial sweat) as non-fearful non-body odors. The two groups did not differ with respect to their olfactory identification ability. Independent of the kind of odor, the patients with PD showed activations in fronto-cortical areas in contrast to the healthy controls who showed activations in olfaction-related areas such as the amygdalae and the hippocampus. For artificial odors, the patients with PD showed a decreased neuronal activation of the thalamus, the posterior cingulate cortex and the anterior cingulate cortex. Under the presentation of sweat odor caused by ergometric exercise, the patients with PD showed an increased activation in the superior temporal gyrus, the supramarginal gyrus, and the cingulate cortex which was positively correlated with the severity of the psychopathology. For the sweat odor from the anxiety condition, the patients with PD showed an increased activation in the gyrus frontalis inferior, which was positively correlated with the severity of the psychopathology. The results suggest altered neuronal processing of olfactory stimuli in PD. Both artificial odors and stress-related body odors activate specific parts of a fear-network which is associated with an increased severity of the psychopathology.

Effects of historically familiar and novel predator odors on the physiology of an introduced prey

PubMed Central

Mella, Valentina S. A.; Cooper, Christine E.; Davies, Stephen J. J. F.

2016-01-01

Abstract Predator odors can elicit fear responses in prey and predator odor recognition is generally associated with physiological responses. Prey species are often more likely to respond to the odor of familiar rather than alien predators. However, predator naïvety in an introduced prey species has rarely been investigated. We examined the physiological response, as shown by changes in ventilatory variables, of an introduced terrestrial herbivore, the European rabbit Oryctolagus cuniculus, in Australia, to the odor of potential predators and to control odors (distilled water and horse), to explore if responses were limited to historical (cat and fox) predators, or extended to historically novel predators (snake and quoll). All odors except distilled water elicited a response, with rabbits showing long-term higher respiratory frequencies and lower tidal volumes after introduction of the odors, indicating an increase in alertness. However, the intensity of the rabbits’ reaction could not be directly linked to any pattern of response with respect to the history of predator–prey relationships. Rabbits exhibited significantly stronger reactions in response to both cat and quoll odors than they did to distilled water, but responses to horse, fox, and snake odor were similar to that of water. Our results show that the introduced rabbit can respond to both historical and novel predators in Australia, and suggest that shared evolutionary history is not necessarily a prerequisite to predator odor recognition. PMID:29491891

Effects of historically familiar and novel predator odors on the physiology of an introduced prey.

PubMed

Mella, Valentina S A; Cooper, Christine E; Davies, Stephen J J F

2016-02-01

Predator odors can elicit fear responses in prey and predator odor recognition is generally associated with physiological responses. Prey species are often more likely to respond to the odor of familiar rather than alien predators. However, predator naïvety in an introduced prey species has rarely been investigated. We examined the physiological response, as shown by changes in ventilatory variables, of an introduced terrestrial herbivore, the European rabbit Oryctolagus cuniculus , in Australia, to the odor of potential predators and to control odors (distilled water and horse), to explore if responses were limited to historical (cat and fox) predators, or extended to historically novel predators (snake and quoll). All odors except distilled water elicited a response, with rabbits showing long-term higher respiratory frequencies and lower tidal volumes after introduction of the odors, indicating an increase in alertness. However, the intensity of the rabbits' reaction could not be directly linked to any pattern of response with respect to the history of predator-prey relationships. Rabbits exhibited significantly stronger reactions in response to both cat and quoll odors than they did to distilled water, but responses to horse, fox, and snake odor were similar to that of water. Our results show that the introduced rabbit can respond to both historical and novel predators in Australia, and suggest that shared evolutionary history is not necessarily a prerequisite to predator odor recognition.

Recognition of Bread Key Odorants by Using Polymer Coated QCMs

NASA Astrophysics Data System (ADS)

Nakai, Takashi; Kouno, Shinji; Hiruma, Naoya; Shuzo, Masaki; Delaunay, Jean-Jacques; Yamada, Ichiro

Polyisobutylene (PIB) polymer and methylphenylsiloxane (25%) diphenylsiloxane (75%) copolymer (OV25) were coated on Quartz Crystal Microbalance (QCM) sensors and used in recognition of bread key odorants. Representative compounds of key roasty odorants of bread were taken as 3-acetylpyridine and benzaldehyde, and representative key fatty odorants were hexanal and (E)-2-nonenal. Both OV25- and PIB-coated QCM fabricated sensors could detect concentration as low as 0.9 ppm of 3-acetylpyridine and 1.2 ppm of (E)-2-nonenal. The sensitivity to 3-acetylpyridine of the OV25-coated QCM was about 1000 times higher than that of ethanol, the major interference compound in bread key odorant analysis. Further, the OV25-coated QCM response was 5-6 times and 2-3 times larger than that of the PIB-coated QCM when exposed to roasty odorants and to fatty odorants, respectively. The difference in sensitivity of the OV25- and PIB-coated QCMs we fabricated made possible to discriminate roasty from fatty odorants as was evidenced by the odor recognition map representing the frequency shifts of the OV25-coated QCM against the frequency shift of the PIB-coated QCM. In conclusion, we found that the combination of an OV25-coated QCM and a PIB-coated QCM was successful in discriminating roasty odorants from fatty odorants at the ppm level.

Case study of odor and indoor air quality assessment in the dewatering building at the Stickney Water Reclamation Plant.

PubMed

Sharma, Manju; O'Connell, Susan; Garelli, Brett; Sattayatewa, Chakkrid; Moschandreas, Demetrios; Pagilla, Krishna

2012-01-01

Indoor air quality (IAQ) and odors were determined using sampling/monitoring, measurement, and modeling methods in a large dewatering building at a very large water reclamation plant. The ultimate goal was to determine control strategies to reduce the sensory impacts on the workforce and achieve odor reduction within the building. Study approaches included: (1) investigation of air mixing by using CO(2) as an indicator, (2) measurement of airflow capacity of ventilation fans, (3) measurement of odors and odorants, (4) development of statistical and IAQ models, and (5) recommendation of control strategies. The results showed that air quality in the building complies with occupational safety and health guidelines; however, nuisance odors that can increase stress and productivity loss still persist. Excess roof fan capacity induced odor dispersion to the upper levels. Lack of a local air exhaust system of sufficient capacity and optimum design was found to be the contributor to occasional less than adequate indoor air quality and odors. Overall, air ventilation rate in the building has less effect on persistence of odors in the building. Odor/odorant emission rates from centrifuge drops were approximately 100 times higher than those from the open conveyors. Based on measurements and modeling, the key control strategies recommended include increasing local air exhaust system capacity and relocation of exhaust hoods closer to the centrifuge drops.

An olfactory cocktail party: figure-ground segregation of odorants in rodents.

PubMed

Rokni, Dan; Hemmelder, Vivian; Kapoor, Vikrant; Murthy, Venkatesh N

2014-09-01

In odorant-rich environments, animals must be able to detect specific odorants of interest against variable backgrounds. However, studies have found that both humans and rodents are poor at analyzing the components of odorant mixtures, suggesting that olfaction is a synthetic sense in which mixtures are perceived holistically. We found that mice could be easily trained to detect target odorants embedded in unpredictable and variable mixtures. To relate the behavioral performance to neural representation, we imaged the responses of olfactory bulb glomeruli to individual odors in mice expressing the Ca(2+) indicator GCaMP3 in olfactory receptor neurons. The difficulty of segregating the target from the background depended strongly on the extent of overlap between the glomerular responses to target and background odors. Our study indicates that the olfactory system has powerful analytic abilities that are constrained by the limits of combinatorial neural representation of odorants at the level of the olfactory receptors.

Effects of extraneous odors on canine detection

NASA Astrophysics Data System (ADS)

Waggoner, L. Paul; Jones, Meredith H.; Williams, Marc; Johnston, J. M.; Edge, Cindy C.; Petrousky, James A.

1998-12-01

Dogs are often required to detect target substances under challenging conditions. One of these challenges is to detect contraband in the presence of extraneous odors, whether they are part of the ambient environment or placed there for the purpose of evading detection. This paper presents the results of two studies evaluating the ability of dogs to detect target substances in the presence of varying concentrations of extraneous odors. The studies were conducted under behavioral laboratory conditions, providing good control over vapor sources and a clear basis for evaluation of detection responses. Dogs were trained to sample an air stream consisting of the extraneous odor only or the extraneous odor plus the target odor and then press the appropriate lever to earn food. The results are described in terns of the ability of dogs to detect target odors in the presence of a wide range of concentrations of the extraneous odors.

Design and analysis of a pilot scale biofiltration system for odorous air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Classen, J.J.; Young, J.S.; Bottcher, R.W.

2000-02-01

Three pilot-scale biofilters and necessary peripheral equipment were built to clean odorous air from the pit of a swine gestation building at North Carolina State University. A computer measured temperatures, flow rates, and pressure drops. It also controlled and measured the moisture content of a biofilter medium comprised of a 3:1 mixture of yard waste compost to wood chips mixture (by volume). The system was evaluated to ensure that the biofilters would be useful for performing scientific experiments concerning the reduction of swine odor on future research projects. The capability of the biofilters to remove odor was measured using amore » cotton swatch absorption method and an odor panel. The average odor reductions measured by odor intensity, irritation intensity, and unpleasantness for five tests were 61%, 58%, and 84%, respectively. No significant differences in odor reduction performance were found between the biofilters.« less

The effects of passive smoking on olfaction in children.

PubMed

Nageris, B; Hadar, T; Hansen, M C

2002-01-01

The effect of passive smoking on odor identification was studied in 10 children exposed to passive smoke at home. All had at least one parent who smoked at least one pack of cigarettes a day. The control group consisted of 10 children of nonsmoking parents. Ten odorants were tested: vinegar, ammonia, peppermint, roses, bleach, vanilla, cough drops, turpentine, licorice and mothballs. Each child was presented with five test trays containing all 10 odorants in random order. Of the total of 500 odors presented, the control group correctly identified 396 (79%) and the study group, 356 (71%) (p < 0.005). This work demonstrates that children exposed to passive smoke have difficulty identifying odors in comparison to children raised in relatively smoke-free environments. Since the study group tend to misidentify four of the 10 odorants tested--vanilla, roses, mothballs and cough drops--we suggest that these four odorants should suffice in testing odor identification in children.

Odors as cues for orientation to mothers by weanling Virginia opossums

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, D.J.

1992-12-01

Three experiments were conducted to investigate whether whole-body and pouch odors facilitate social cohesion between young Virginia opossums and their mothers just prior to weaning. In experiment 1, young oriented toward plastic buckets containing their mothers, directing significantly higher levels of investigative behavior and more distress vocalizations toward them than toward buckets containing unrelated lactating females. In experiment 2, young oriented toward and investigated empty buckets containing whole-body odors of their mothers more than empty buckets containing odors of other females. Similarly, more investigative behavior was directed toward plastic bucket lids containing pouch odors from subjects mothers than toward pouchmore » odors from unrelated females in experiment 3. These results suggest that social odors help young didelphid marsupials maintain contact with their mothers, as in other mammals, and that whole-body and pouch gland odors are important chemical signals in this nongregarious species.« less

Application of a putative alarm cue hastens the arrival of invasive sea lamprey (Petromyzon marinus) at a trapping location

USGS Publications Warehouse

Hume, John B.; Meckley, Trevor D.; Johnson, Nicholas; Luhring, Thomas M; Siefkes, Michael J; Wagner, C. Michael

2015-01-01

The sea lamprey Petromyzon marinus is an invasive pest in the Laurentian Great Lakes basin, threatening the persistence of important commercial and recreational fisheries. There is substantial interest in developing effective trapping practices via the application of behavior-modifying semiochemicals (odors). Here we report on the effectiveness of utilizing repellent and attractant odors in a push–pull configuration, commonly employed to tackle invertebrate pests, to improve trapping efficacy at permanent barriers to sea lamprey migration. When a half-stream channel was activated by a naturally derived repellent odor (a putative alarm cue), we found that sea lamprey located a trap entrance significantly faster than when no odor was present as a result of their redistribution within the stream. The presence of a partial sex pheromone, acting as an attractant within the trap, was not found to further decrease the time to when sea lamprey located a trap entrance relative to when the alarm cue alone was applied. Neither the application of alarm cue singly nor alarm cue and partial sex pheromone in combination was found to improve the numbers of sea lamprey captured in the trap versus when no odor was present — likely because nominal capture rate during control trials was unusually high during the study period. Behavioural guidance using these odors has the potential to both improve control of invasive non-native sea lamprey in the Great Lakes as well as improving the efficiency of fish passage devices used in the restoration of threatened lamprey species elsewhere.

Transcriptomes of Mouse Olfactory Epithelium Reveal Sexual Differences in Odorant Detection

PubMed Central

Shiao, Meng-Shin; Chang, Andrew Ying-Fei; Liao, Ben-Yang; Ching, Yung-Hao; Lu, Mei-Yeh Jade; Chen, Stella Maris; Li, Wen-Hsiung

2012-01-01

To sense numerous odorants and chemicals, animals have evolved a large number of olfactory receptor genes (Olfrs) in their genome. In particular, the house mouse has ∼1,100 genes in the Olfr gene family. This makes the mouse a good model organism to study Olfr genes and olfaction-related genes. To date, whether male and female mice possess the same ability in detecting environmental odorants is still unknown. Using the next generation sequencing technology (paired-end mRNA-seq), we detected 1,088 expressed Olfr genes in both male and female olfactory epithelium. We found that not only Olfr genes but also odorant-binding protein (Obp) genes have evolved rapidly in the mouse lineage. Interestingly, Olfr genes tend to express at a higher level in males than in females, whereas the Obp genes clustered on the X chromosome show the opposite trend. These observations may imply a more efficient odorant-transporting system in females, whereas a more active Olfr gene expressing system in males. In addition, we detected the expression of two genes encoding major urinary proteins, which have been proposed to bind and transport pheromones or act as pheromones in mouse urine. This observation suggests a role of main olfactory system (MOS) in pheromone detection, contrary to the view that only accessory olfactory system (AOS) is involved in pheromone detection. This study suggests the sexual differences in detecting environmental odorants in MOS and demonstrates that mRNA-seq provides a powerful tool for detecting genes with low expression levels and with high sequence similarities. PMID:22511034

Assessment of the aroma impact of major odor-active thiols in pan-roasted white sesame seeds by calculation of odor activity values.

PubMed

Tamura, Hitoshi; Fujita, Akira; Steinhaus, Martin; Takahisa, Eisuke; Watanabe, Hiroyuki; Schieberle, Peter

2011-09-28

Eleven odor-active thiols, namely, 2-methyl-1-propene-1-thiol, (Z)-3-methyl-1-butene-1-thiol, (E)-3-methyl-1-butene-1-thiol, (Z)-2-methyl-1-butene-1-thiol, (E)-2-methyl-1-butene-1-thiol, 2-methyl-3-furanthiol, 3-mercapto-2-pentanone, 2-mercapto-3-pentanone, 4-mercapto-3-hexanone, 3-mercapto-3-methylbutyl formate, and 2-methyl-3-thiophenethiol, recently identified in an extract prepared from white sesame seeds, were quantitated in sesame using stable isotope dilution analyses. For that purpose, the following deuterium-labeled compounds were synthesized and used as internal standards in the quantitation assays: [2H6]-2-methyl-1-propene-1-thiol, [2H3]-(E)- and [2H3]-(Z)-2-methyl-1-butene-1-thiol, [2H3]-2-methyl-3-furanthiol, [2H2]-3-mercapto-2-pentanone, [2H3]-4-mercapto-3-hexanone, [2H6]-3-mercapto-3-methylbutyl formate, and [2H3]-2-methyl-3-thiophenethiol. On the basis of the results obtained, odor activity values (OAVs) were calculated as ratio of the concentration and odor threshold of the individual compounds in cooking oil. According to their high OAVs, particularly the 3-methyl-1-butene-1-thiols (OAV: 2400) and the 2-methyl-1-butene-1-thiols (OAV: 960) were identified as the most odor-active compounds in pan-roasted white sesame seeds. These compounds were therefore suggested to be mainly responsible for the characteristic but rather unstable sulfury aroma of freshly pan-roasted white sesame seeds.

The banana code—natural blend processing in the olfactory circuitry of Drosophila melanogaster

PubMed Central

Schubert, Marco; Hansson, Bill S.; Sachse, Silke

2014-01-01

Odor information is predominantly perceived as complex odor blends. For Drosophila melanogaster one of the most attractive blends is emitted by an over-ripe banana. To analyze how the fly's olfactory system processes natural blends we combined the experimental advantages of gas chromatography and functional imaging (GC-I). In this way, natural banana compounds were presented successively to the fly antenna in close to natural occurring concentrations. This technique allowed us to identify the active odor components, use these compounds as stimuli and measure odor-induced Ca2+ signals in input and output neurons of the Drosophila antennal lobe (AL), the first olfactory neuropil. We demonstrate that mixture interactions of a natural blend are very rare and occur only at the AL output level resulting in a surprisingly linear blend representation. However, the information regarding single components is strongly modulated by the olfactory circuitry within the AL leading to a higher similarity between the representation of individual components and the banana blend. This observed modulation might tune the olfactory system in a way to distinctively categorize odor components and improve the detection of suitable food sources. Functional GC-I thus enables analysis of virtually any unknown natural odorant blend and its components in their relative occurring concentrations and allows characterization of neuronal responses of complete neural assemblies. This technique can be seen as a valuable complementary method to classical GC/electrophysiology techniques, and will be a highly useful tool in future investigations of insect-insect and insect-plant chemical interactions. PMID:24600405

Apolipoprotein e4 Is Associated with More Rapid Decline in Odor Identification than in Odor Threshold or Dementia Rating Scale Scores

ERIC Educational Resources Information Center

Calhoun-Haney, R.; Murphy, C.

2005-01-01

Individuals with the apolipoprotein E e4 genetic risk factor for Alzheimer's disease (AD) show deficits in olfactory function. The purpose of the present study was to examine longitudinally odor identification (odor ID), odor threshold, picture identification, and global cognitive status in allele positive (e4+) and negative (e4-) persons.…

Differential Odor Sensitivity in PTSD: Implications for Treatment and Future Research

PubMed Central

Cortese, Bernadette M.; Leslie, Kimberly; Uhde, Thomas W.

2015-01-01

Background Given that odors enhance the retrieval of autobiographical memories, induce physiological arousal, and trigger trauma-related flashbacks, it is reasonable to hypothesize that odors play a significant role in the pathophysiology of posttraumatic stress disorder (PTSD). For these reasons, this preliminary study sought to examine self-reported, odor-elicited distress in PTSD. Methods Combat veterans with (N=30) and without (N=22) PTSD and healthy controls (HC: N=21), completed an olfactory questionnaire that provided information on the hedonic valence of odors as well as their ability to elicit distress or relaxation. Results Two main findings were revealed: Compared to HC, CV+PTSD, but not CV-PTSD, reported a higher prevalence of distress to a limited number of select odors that included fuel (p=.004), blood (p=.02), gunpowder (p=.03), and burning hair (p=.02). In contrast to this increased sensitivity, a blunting effect was reported by both groups of veterans compared to HC that revealed lower rates of distress and relaxation in response to negative hedonic odors (p=.03) and positive hedonic odors (p<.001), respectively. Limitations The study is limited by its use of retrospective survey methods, whereas future investigations would benefit from laboratory measures taken prior, during, and after deployment. Conclusion The present findings suggest a complex role of olfaction in the biological functions of threat detection. Several theoretical models are discussed. One possible explanation for increased sensitivity to select odors with decreased sensitivity to other odors is the co-occurrence of attentional bias toward threat odors with selective ignoring of distractor odors. Working together, these processes may optimize survival. PMID:25845746

Levels-of-processing effects on a task of olfactory naming.

PubMed

Royet, Jean-Pierre; Koenig, Olivier; Paugam-Moisy, Helene; Puzenat, Didier; Chasse, Jean-Luc

2004-02-01

The effects of odor processing were investigated at various analytical levels, from simple sensory analysis to deep or semantic analysis, on a subsequent task of odor naming. Students (106 women, 23.6 +/- 5.5 yr. old; 65 men, 25.1 +/- 7.1 yr. old) were tested. The experimental procedure included two successive sessions, a first session to characterize a set of 30 odors with criteria that used various depths of processing and a second session to name the odors as quickly as possible. Four processing conditions rated the odors using descriptors before naming the odor. The control condition did not rate the odors before naming. The processing conditions were based on lower-level olfactory judgments (superficial processing), higher-level olfactory-gustatory-somesthetic judgments (deep processing), and higher-level nonolfactory judgments (Deep-Control processing, with subjects rating odors with auditory and visual descriptors). One experimental condition successively grouped lower- and higher-level olfactory judgments (Superficial-Deep processing). A naming index which depended on response accuracy and the subjects' response time were calculated. Odor naming was modified for 18 out of 30 odorants as a function of the level of processing required. For 94.5% of significant variations, the scores for odor naming were higher following those tasks for which it was hypothesized that the necessary olfactory processing was carried out at a deeper level. Performance in the naming task was progressively improved as follows: no rating of odors, then superficial, deep-control, deep, and superficial-deep processings. These data show that the deepest olfactory encoding was later associated with progressively higher performance in naming.

Identity-Specific Reward Representations in Orbitofrontal Cortex Are Modulated by Selective Devaluation.

PubMed

Howard, James D; Kahnt, Thorsten

2017-03-08

Goal-directed behavior is sensitive to the current value of expected outcomes. This requires independent representations of specific rewards, which have been linked to orbitofrontal cortex (OFC) function. However, the mechanisms by which the human brain updates specific goals on the fly, and translates those updates into choices, have remained unknown. Here we implemented selective devaluation of appetizing food odors in combination with pattern-based neuroimaging and a decision-making task. We found that in a hungry state, participants chose to smell high-intensity versions of two value-matched food odor rewards. After eating a meal corresponding to one of the two odors, participants switched choices toward the low intensity of the sated odor but continued to choose the high intensity of the nonsated odor. This sensory-specific behavioral effect was mirrored by pattern-based changes in fMRI signal in lateral posterior OFC, where specific reward identity representations were altered after the meal for the sated food odor but retained for the nonsated counterpart. In addition, changes in functional connectivity between the OFC and general value coding in ventromedial prefrontal cortex (vmPFC) predicted individual differences in satiety-related choice behavior. These findings demonstrate how flexible representations of specific rewards in the OFC are updated by devaluation, and how functional connections to vmPFC reflect the current value of outcomes and guide goal-directed behavior. SIGNIFICANCE STATEMENT The orbitofrontal cortex (OFC) is critical for goal-directed behavior. A recent proposal is that OFC fulfills this function by representing a variety of state and task variables ("cognitive maps"), including a conjunction of expected reward identity and value. Here we tested how identity-specific representations of food odor reward are updated by satiety. We found that fMRI pattern-based signatures of reward identity in lateral posterior OFC were modulated after selective devaluation, and that connectivity between this region and general value coding ventromedial prefrontal cortex (vmPFC) predicted choice behavior. These results provide evidence for a mechanism by which devaluation modulates a cognitive map of expected reward in OFC and thereby alters general value signals in vmPFC to guide goal-directed behavior. Copyright © 2017 the authors 0270-6474/17/372627-12$15.00/0.

Seeing odors in color: Cross-modal associations in children and adults from two cultural environments.

PubMed

Goubet, Nathalie; Durand, Karine; Schaal, Benoist; McCall, Daniel D

2018-02-01

We investigated the occurrence and underlying processes of odor-color associations in French and American 6- to 10-year-old children (n = 386) and adults (n = 137). Nine odorants were chosen according to their familiarity to either cultural group. Participants matched each odor with a color, gave hedonic and familiarity judgments, and identified each odor. By 6 years of age, children displayed culture-specific odor-color associations, but age differences were noted in the type of associations. Children and adults in both cultural groups shared common associations and formed associations that were unique to their environment, underscoring the importance of exposure learning in odor-color associations. Copyright © 2017 Elsevier Inc. All rights reserved.

IDENTIFICATION OF ODOR SUBSTANCES IN YAMABUSHITAKE MUSHROOM (Hericium erinaceum) CULTURE MEDIA CONTAINING 'SHOCHU' LEES AND STARCH WASTES, AND BASIC STUDIES ON THEIR DISAPPEARANCE

NASA Astrophysics Data System (ADS)

Yamauchi, Masahito; Matsumoto, Hirotaka; Yamada, Masayoshi; Yagi, Fumio; Murayama, Ryou; Yamaguchi, Yoshinori; Yamaguchi, Takashi

In this study, odor substances from mushroom culture media containing 'shochu' lees and starch wastes were identified and determined. It was apparent that in the media, acetoin, butyric acid and diacetyl were found as main odor substances, and mixed with some other ordor substances to produce unpleasant odor. The main substances disappeared with growth of mycelia. It was not likely that these ordor substances were degraded by extracellular enzymes but suggested that they were degraded by mycelia. Further it was found with the growth of mycelia that odor quality changed from rancid ordor (unpleasant ordor) to mushroom smell (pleasant odor) and the odor index was decreasing.

Differential Dynamics of Amino Acid Release in the Amygdala and Olfactory Cortex during Odor Fear Acquisition as Revealed with Simultaneous High Temporal Resolution Microdialysis

ERIC Educational Resources Information Center

Hegoburu, Chloe; Sevelinges, Yannick; Thevenet, Marc; Gervais, Remi; Parrot, Sandrine; Mouly, Anne-Marie

2009-01-01

Although the amygdala seems to be essential to the formation and storage of fear memories, it might store only some aspects of the aversive event and facilitate the storage of more specific sensory aspects in cortical areas. We addressed the time course of amygdala and cortical activation in the context of odor fear conditioning in rats. Using…

Selecting odorant compounds to enhance sweet flavor perception by gas chromatography/olfactometry-associated taste (GC/O-AT).

PubMed

Barba, Carmen; Beno, Noelle; Guichard, Elisabeth; Thomas-Danguin, Thierry

2018-08-15

Gas chromatography/olfactometry-associated taste (GC/O-AT) analysis combined with mass spectrometry allowed identification of odorant compounds associated with taste attributes (sweet, salty, bitter and sour) in a multi-fruit juice. Nine compounds were selected for their odor-associated sweetness enhancement in a multi-fruit juice odor context using Olfactoscan and for their odor-induced sweet taste enhancement in sucrose solution and sugar-reduced fruit juice through sensory tests. Sweetness of the fruit juice odor was significantly enhanced by methyl 2-methylbutanoate, ethyl butanoate, ethyl 2-methylbutanoate and linalool; sweet perception was significantly enhanced in 7% sucrose solution by ethyl 2-methylbutanoate, furaneol and γ-decalactone, and in 32% sugar-reduced fruit juice by ethyl 2-methylbutanoate. GC/O-AT analysis is a novel, efficient approach to select odorants associated with a given taste. The further screening of taste-associated odorants by Olfactoscan helps to identify the most efficient odorants to enhance a target taste perception and may be used to find new ways to modulate taste perception in foods and beverages. Copyright © 2018 Elsevier Ltd. All rights reserved.

Identification of Odorant-Receptor Interactions by Global Mapping of the Human Odorome

PubMed Central

Audouze, Karine; Tromelin, Anne; Le Bon, Anne Marie; Belloir, Christine; Petersen, Rasmus Koefoed; Kristiansen, Karsten; Brunak, Søren; Taboureau, Olivier

2014-01-01

The human olfactory system recognizes a broad spectrum of odorants using approximately 400 different olfactory receptors (hORs). Although significant improvements of heterologous expression systems used to study interactions between ORs and odorant molecules have been made, screening the olfactory repertoire of hORs remains a tremendous challenge. We therefore developed a chemical systems level approach based on protein-protein association network to investigate novel hOR-odorant relationships. Using this new approach, we proposed and validated new bioactivities for odorant molecules and OR2W1, OR51E1 and OR5P3. As it remains largely unknown how human perception of odorants influence or prevent diseases, we also developed an odorant-protein matrix to explore global relationships between chemicals, biological targets and disease susceptibilities. We successfully experimentally demonstrated interactions between odorants and the cannabinoid receptor 1 (CB1) and the peroxisome proliferator-activated receptor gamma (PPARγ). Overall, these results illustrate the potential of integrative systems chemical biology to explore the impact of odorant molecules on human health, i.e. human odorome. PMID:24695519

Functional neuronal processing of human body odors.

PubMed

Lundström, Johan N; Olsson, Mats J

2010-01-01

Body odors carry informational cues of great importance for individuals across a wide range of species, and signals hidden within the body odor cocktail are known to regulate several key behaviors in animals. For a long time, the notion that humans may be among these species has been dismissed. We now know, however, that each human has a unique odor signature that carries information related to his or her genetic makeup, as well as information about personal environmental variables, such as diet and hygiene. Although a substantial number of studies have investigated the behavioral effects of body odors, only a handful have studied central processing. Recent studies have, however, demonstrated that the human brain responds to fear signals hidden within the body odor cocktail, is able to extract kin specific signals, and processes body odors differently than other perceptually similar odors. In this chapter, we provide an overview of the current knowledge of how the human brain processes body odors and the potential importance these signals have for us in everyday life. Copyright © 2010 Elsevier Inc. All rights reserved.

Odors and incontinence: What does the nose know?

PubMed

Dalton, Pamela; Maute, Christopher

2018-06-01

The fear of producing malodors that can be detected by others is a daily cause of anxiety for millions of people with incontinence. For many, the risk-whether real or imagined-that leaked waste products will be detectable by odor is sufficiently concerning to result in limitations on many types of activities. However, worry about personal odors can sensitize our olfactory system and cause us to be more aware of odors that may otherwise not be perceptible. In addition, heightened olfactory attention can often lead to odor misattributions, such as when we erroneously identify our body as the source of an odor that may simply be present in the environment. Odors produced by our bodies (endogenous odors) do enjoy a greater access to emotional brain centers and are processed faster than general odors. Here we provide examples from both everyday life and laboratory studies to explain how and why the olfactory system is unique among our sensory systems and how this knowledge can provide insights to our concerns about smell and incontinence and inform the development of products and solutions for incontinence.

Odors as cues for the recall of words unrelated to odor.

PubMed

Morgan, C L

1996-12-01

The effectiveness of an ambient odor as a retrieval cue for words unrelated to odor was investigated. After incidental learning of 40 adjectives, 40 participants were tested for recall during three unannounced recall phases (15 min., 48 hr., and 5 days). Participants in two control conditions learned with no odor present and either had no odor present during any recall phase or only during recall after 5 days. Participants in two conditions learned with an odor present and either had the odor present during recall only after 5 days or during recall both after 15 min. and after 5 days. Analyses indicated that, while participants in the control conditions recalled significantly less during each succeeding recall phase, recall by participants in the two experimental conditions did not decrease significantly. Recall by participants in the two experimental conditions was significantly higher during recall after 5 days (when the odor was reintroduced) than either control group. The addition of a salient cue during learning and retrieval facilitated recall more than the presence of constant environmental cues.

Odor from a chemical perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wray, T.K.

1995-06-01

Early odor-detection measurements categorized chemicals according to odor quality. Recent methods focus on the odor threshold, or the quantitative amount of a chemical in air that can be detected by the human sense of smell. Researchers characterize and quantify odor using an array of sensory and analytical procedures. Humans possess one of the dullest mammalian senses of smell; however, they can recognize about 10,000 distinct odors at concentrations ranging from less than 1 part per billion to several hundred thousand parts per million. Each time humans inhale, they chemically analyze microscopic pieces of the environment that make physical contact withmore » the nerves in their noses. Individual molecules travel up the nose to a sheet of moist, mucus-bathed tissue that consists of about 5 million smell-sensing, olfactory neurons. After dissolving in the mucus, odor molecules ``float`` into appropriately shaped receptor pockets. A series of cellular reactions then transmit impulses to the limbic system, hippocampus and, finally, the neocortex. Odor detection is an important defense mechanism. The author presents the odor thresholds for selected organic compounds, and other hazardous chemicals.« less

THE EFFECTS OF HIGH VOLTAGE CATHODE RAY IONIZING RADIATION ON SOME OF THE PHYSICAL AND CHEMICAL PROPERTIES OF WHEAT FLOUR PROTEIN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alsup, E.B.

1959-01-01

The effect of irradiation on some of the physical and chemical properties of wheat flour protein was determined. A study of the baking quality and palatability of an irradiated flour product, yields of crude gluten from irradiated flour, and electrophoretic analyses of some of the protein fractions of irradiated flour were studied. Triangle taste tests indicated that 50000 rep was the dosage level at which the irradiation treatment of flour could be detected in baking powder biscuits. Taste panel scores for color, odor, and baking characteristics of biscuits made with flour treated with 100000 rep or less of ionizing radiation,more » however, were not significantly different from the scores for the control biscuits. An off-odor and darkening in color of the biscuits were readily apparent at a dosage of 500000 rep. The weight of crude gluten extracted from flour was greater from flour exposed to dosages of 1000000 rep or less than from the control flour, but no differences were found in the volumes of the baked balls of crude gluten. This indicates a greater water retention with the irradiated flour. Very small yields of crude gluten at dosages of 3000000 rep or more indicated that definite changes had occurred in the protein structure. Electrophoretic analyses by the moving boundary method were performed on acetic acid extracts of whole flour in a citric acid-disodium phos, phate buffer pH 2.2, ionic strength 0.024. Electrophoretic patterns obtained from the non-irradiated flour indicated that there were at least six separate protein components present, including one which was fast-moving and high in relative concentration, one which was slow-moving and medium high in relative concentration, and four relatively small components. Irradiation of the flour with 300000 rep produced no apparent changes in the electrophoretic patterns obtained, but it 1000000 rep or more, the relative concentrations of the two largest components were changed (the slow-moving one becoming larger and the fastermoving one smaller with each increase in dosage). Also with increased radiation dosages, the peaks of the smaller components became less distinct until only the two main peaks were distinguishable at 10000000 rep. (Dissertition Abstr., 23: No. 4, 1962)« less

Marked dissociation between hypothalamic-pituitary-adrenal activation and long-term behavioral effects in rats exposed to immobilization or cat odor.

PubMed

Muñoz-Abellán, C; Andero, R; Nadal, R; Armario, A

2008-09-01

Exposure of rodents to cats or certain cat odors results in long-term behavioral effects reminiscent of enhanced anxiety that have been considered to model post-traumatic stress disorder. However, other severe stressors such as tail-shock or immobilization in wooden boards (IMO) appear to induce shorter lasting changes in anxiety. In addition, there are controversial results regarding the effects of urine/feces odors. In the present work, we studied in two experiments the relationship between the degree of stress experienced by the animals during exposure to IMO, urine odors or fur odors (as assessed by hypothalamic-pituitary-adrenal activation and plasma glucose) and the short- and long-term behavioral consequences. In the first experiment, rats were individually exposed for 15 min to a novel environment (white large cages) containing either clean cat litter (controls) or litter soiled by cats (urine odors). Half of the rats in each condition were left to freely explore the environment whereas the others were subjected to immobilization (IMO) within the cages. Although ACTH, corticosterone and glucose responses to IMO were much stronger than those to the white cages with clean litter or urine odors (which did not differ from each other), no effect of treatments on anxiety-like behavior in the elevated plus-maze (EPM) were found one week later. However, previous IMO exposure did cause sensitization of the ACTH response to the EPM. In the second experiment, the response to white large cages containing either no odor (controls), litter soiled by cats (urine odor) or a cloth impregnated with cat odor (fur odor) was compared. Urine and fur odors elicited similar ACTH and corticosterone responses that were higher than those of controls, but plasma glucose levels were slightly higher in rats exposed to fur odor. When compared to controls, activity was only diminished in the novel cages containing fur odor. Similarly, fur odor-exposed rats, but not those exposed to urine odor, showed signs of enhanced anxiety in the EPM seven days later, although the ACTH response to the EPM was similar in the three groups. The present data demonstrate: (a) a marked dissociation between the degree of ACTH, corticosterone and glucose responses to stressors and their long-term anxiety-like effects; (b) that the type of cat odor is critical in determining the short-term and long-term physiological and behavioral consequences of exposure; and (c) that plasma ACTH released during brief exposure to the EPM does not appear to reflect anxiety-like behavior.

Combining Ordinary Kriging with wind directions to identify sources of industrial odors in Portland, Oregon.

PubMed

Eckmann, Ted C; Wright, Samantha G; Simpson, Logan K; Walker, Joe L; Kolmes, Steven A; Houck, James E; Velasquez, Sandra C

2018-01-01

This study combines Ordinary Kriging, odor monitoring, and wind direction data to demonstrate how these elements can be applied to identify the source of an industrial odor. The specific case study used as an example of how to address this issue was the University Park neighborhood of Portland, Oregon (USA) where residents frequently complain about industrial odors, and suspect the main source to be a nearby Daimler Trucks North America LLC manufacturing plant. We collected 19,665 odor observations plus 105,120 wind measurements, using an automated weather station to measure winds in the area at five-minute intervals, logging continuously from December 2014 through November 2015, while we also measured odors at 19 locations, three times per day, using methods from the American Society of the International Association for Testing and Materials. Our results quantify how winds vary with season and time of day when industrial odors were observed versus when they were not observed, while also mapping spatiotemporal patterns in these odors using Ordinary Kriging. Our analyses show that industrial odors were detected most frequently to the northwest of the Daimler plant, mostly when winds blew from the southeast, suggesting Daimler's facility is a likely source for much of this odor.

The olfactory hole-board test in rats: a new paradigm to study aversion and preferences to odors

PubMed Central

Wernecke, Kerstin E. A.; Fendt, Markus

2015-01-01

Odors of biological relevance (e.g., predator odors, sex odors) are known to effectively influence basic survival needs of rodents such as anti-predatory defensiveness and mating behaviors. Research focused on the effects of these odors on rats’ behavior mostly includes multi-trial paradigms where animals experience single odor exposures in subsequent, separated experimental sessions. In the present study, we introduce a modification of the olfactory hole-board test that allows studying the effects of different odors on rats’ behavior within single trials. First, we demonstrated that the corner holes of the hole-board were preferentially visited by rats. The placement of different odors under the corner holes changed this hole preference. We showed that holes with carnivore urine samples were avoided, while corner holes with female rat urine samples were preferred. Furthermore, corner holes with urine samples from a carnivore, herbivore, and omnivore were differentially visited indicating that rats can discriminate these odors. To test whether anxiolytic treatment specifically modulates the avoidance of carnivore urine holes, we treated rats with buspirone. Buspirone treatment completely abolished the avoidance of carnivore urine holes. Taken together, our findings indicate that the olfactory hole-board test is a valuable tool for measuring avoidance and preference responses to biologically relevant odors. PMID:26379516

Composition of key offensive odorants released from fresh food materials

NASA Astrophysics Data System (ADS)

Kim, Ki-Hyun; Kim, Yong-Hyun

2014-06-01

A refrigerator loaded with a variety of foods without sealed packaging can create quite an olfactory nuisance, and it may come as a surprise that fresh foods emit unpleasant odorants just as those that are decaying. To learn more about nuisance sources in our daily lives, we measured a list of 22 compounds designated as the key offensive odorants (e.g., reduced sulfur, nitrogenous, volatile fatty acid (VFA), and carbonyls) from nine types of common food items consumed in S. Korea: raw beef, raw fish, spam, yolks and albumin of boiled eggs (analyzed separately), milk, cheese, onions, and strawberries. The odor intensity (OI) of each food item was computed initially with the aid of previously used empirical equations. This indicates that the malodor properties of target foods tend to be governed by a few key odorants such as VFA, S, and N compounds. The extent of odorant mixing of a given food was then evaluated by exploring the correlation between the human olfaction (e.g., dilution-to-threshold (D/T) ratio) and the odor potential determined indirectly (instrumentally) such as odor activity value (OAV) or sum of odor intensity (SOI). The overall results of our study confirm the existence of malodorant compounds released from common food items and their contribution to their odor characteristics to a certain degree.

Family scents: developmental changes in the perception of kin body odor?

PubMed

Ferdenzi, Camille; Schaal, Benoist; Roberts, S Craig

2010-08-01

There is increasing evidence that human body odors are involved in adaptive behaviors, such as parental attachment in infants or partner choice in adults. The aim of the present study was to investigate changes in body-odor perception around puberty, a period largely ignored for odor-mediated behavioral changes, despite major changes in social needs and in odor emission and perception. Nine families with two children (8 pre-pubertal, aged 7-10, and 10 pubertal, aged 11-18) evaluated body odors of family members and unfamiliar individuals for pleasantness, intensity, and masculinity, and performed a recognition task. The hypothesized emergence of a parent-child mutual aversion for the odor of opposite-sex family members at puberty was not found, contradicting one of the few studies on the topic (Weisfeld et al., J. Exp. Child Psychol. 85:279-295, 2003). However, some developmental changes were observed, including reduced aversion for odor of the same-sex parent, and increased ability of adults, compared to children, to recognize odor of family members. Sex and personality (depressive and aggressive traits) also significantly influenced odor judgments. Further research with larger samples is needed to investigate the poorly explored issue of how olfactory perception of self and family members develops, and how it could correlate with normal reorganizations in social interactions at adolescence.

Behavioral responses to odors from other species: introducing a complementary model of allelochemics involving vertebrates

PubMed Central

Nielsen, Birte L.; Rampin, Olivier; Meunier, Nicolas; Bombail, Vincent

2015-01-01

It has long been known that the behavior of an animal can be affected by odors from another species. Such interspecific effects of odorous compounds (allelochemics) are usually characterized according to who benefits (emitter, receiver, or both) and the odors categorized accordingly (allomones, kairomones, and synomones, respectively), which has its origin in the definition of pheromones, i.e., intraspecific communication via volatile compounds. When considering vertebrates, however, interspecific odor-based effects exist which do not fit well in this paradigm. Three aspects in particular do not encompass all interspecific semiochemical effects: one relates to the innateness of the behavioral response, another to the origin of the odor, and the third to the intent of the message. In this review we focus on vertebrates, and present examples of behavioral responses of animals to odors from other species with specific reference to these three aspects. Searching for a more useful classification of allelochemical effects we examine the relationship between the valence of odors (attractive through to aversive), and the relative contributions of learned and unconditioned (innate) behavioral responses to odors from other species. We propose that these two factors (odor valence and learning) may offer an alternative way to describe the nature of interspecific olfactory effects involving vertebrates compared to the current focus on who benefits. PMID:26161069

Combining Ordinary Kriging with wind directions to identify sources of industrial odors in Portland, Oregon

PubMed Central

Kolmes, Steven A.; Houck, James E.; Velasquez, Sandra C.

2018-01-01

This study combines Ordinary Kriging, odor monitoring, and wind direction data to demonstrate how these elements can be applied to identify the source of an industrial odor. The specific case study used as an example of how to address this issue was the University Park neighborhood of Portland, Oregon (USA) where residents frequently complain about industrial odors, and suspect the main source to be a nearby Daimler Trucks North America LLC manufacturing plant. We collected 19,665 odor observations plus 105,120 wind measurements, using an automated weather station to measure winds in the area at five-minute intervals, logging continuously from December 2014 through November 2015, while we also measured odors at 19 locations, three times per day, using methods from the American Society of the International Association for Testing and Materials. Our results quantify how winds vary with season and time of day when industrial odors were observed versus when they were not observed, while also mapping spatiotemporal patterns in these odors using Ordinary Kriging. Our analyses show that industrial odors were detected most frequently to the northwest of the Daimler plant, mostly when winds blew from the southeast, suggesting Daimler’s facility is a likely source for much of this odor. PMID:29385136

Cross-Cultural Color-Odor Associations

PubMed Central

Levitan, Carmel A.; Ren, Jiana; Woods, Andy T.; Boesveldt, Sanne; Chan, Jason S.; McKenzie, Kirsten J.; Dodson, Michael; Levin, Jai A.; Leong, Christine X. R.; van den Bosch, Jasper J. F.

2014-01-01

Colors and odors are associated; for instance, people typically match the smell of strawberries to the color pink or red. These associations are forms of crossmodal correspondences. Recently, there has been discussion about the extent to which these correspondences arise for structural reasons (i.e., an inherent mapping between color and odor), statistical reasons (i.e., covariance in experience), and/or semantically-mediated reasons (i.e., stemming from language). The present study probed this question by testing color-odor correspondences in 6 different cultural groups (Dutch, Netherlands-residing-Chinese, German, Malay, Malaysian-Chinese, and US residents), using the same set of 14 odors and asking participants to make congruent and incongruent color choices for each odor. We found consistent patterns in color choices for each odor within each culture, showing that participants were making non-random color-odor matches. We used representational dissimilarity analysis to probe for variations in the patterns of color-odor associations across cultures; we found that US and German participants had the most similar patterns of associations, followed by German and Malay participants. The largest group differences were between Malay and Netherlands-resident Chinese participants and between Dutch and Malaysian-Chinese participants. We conclude that culture plays a role in color-odor crossmodal associations, which likely arise, at least in part, through experience. PMID:25007343

From Nose to Memory: The Involuntary Nature of Odor-evoked Autobiographical Memories in Alzheimer's Disease.

PubMed

El Haj, Mohamad; Gandolphe, Marie Charlotte; Gallouj, Karim; Kapogiannis, Dimitrios; Antoine, Pascal

2017-12-25

Research suggests that odors may serve as a potent cue for autobiographical retrieval. We tested this hypothesis in Alzheimer's disease (AD) and investigated whether odor-evoked autobiographical memory is an involuntary process that shares similarities with music-evoked autobiographical memory. Participants with mild AD and controls were asked to retrieve 2 personal memories after odor exposure, after music exposure, and in an odor-and music-free condition. AD participants showed better specificity, emotional experience, mental time travel, and retrieval time after odor and music exposure than in the control condition. Similar beneficial effects of odor and music exposure were observed for autobiographical characteristics (i.e., specificity, emotional experience, and mental time travel), except for retrieval time which was more improved after odor than after music exposure. Interestingly, regression analyses suggested executive involvement in memories evoked in the control condition but not in those evoked after music or odor exposure. These findings suggest the involuntary nature of odor-evoked autobiographical memory in AD. They also suggest that olfactory cuing could serve as a useful and ecologically valid tool to stimulate autobiographical memory, at least in the mild stage of the disease. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Odorants selectively activate distinct G protein subtypes in olfactory cilia.

PubMed

Schandar, M; Laugwitz, K L; Boekhoff, I; Kroner, C; Gudermann, T; Schultz, G; Breer, H

1998-07-03

Chemoelectrical signal transduction in olfactory neurons appears to involve intracellular reaction cascades mediated by heterotrimeric GTP-binding proteins. In this study attempts were made to identify the G protein subtype(s) in olfactory cilia that are activated by the primary (odorant) signal. Antibodies directed against the alpha subunits of distinct G protein subtypes interfered specifically with second messenger reponses elicited by defined subsets of odorants; odor-induced cAMP-formation was attenuated by Galphas antibodies, whereas Galphao antibodies blocked odor-induced inositol 1,4, 5-trisphosphate (IP3) formation. Activation-dependent photolabeling of Galpha subunits with [alpha-32P]GTP azidoanilide followed by immunoprecipitation using subtype-specific antibodies enabled identification of particular individual G protein subtypes that were activated upon stimulation of isolated olfactory cilia by chemically distinct odorants. For example odorants that elicited a cAMP response resulted in labeling of a Galphas-like protein, whereas odorants that elicited an IP3 response led to the labeling of a Galphao-like protein. Since odorant-induced IP3 formation was also blocked by Gbeta antibodies, activation of olfactory phospholipase C might be mediated by betagamma subunits of a Go-like G protein. These results indicate that different subsets of odorants selectively trigger distinct reaction cascades and provide evidence for dual transduction pathways in olfactory signaling.

Characterisation of odorants in roasted stem tea using gas chromatography-mass spectrometry and gas chromatography-olfactometry analysis.

PubMed

Sasaki, Tetsuya; Koshi, Erina; Take, Harumi; Michihata, Toshihide; Maruya, Masachika; Enomoto, Toshiki

2017-04-01

Roasted stem tea has a characteristic flavour, which is obtained by roasting tea stems, by-product of green tea production. This research aims to understand the characteristic odorants in roasted stem tea by comparing it to roasted leaf tea. We revealed potent odorants in commercial roasted stem tea using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry with aroma extract dilution analysis (AEDA). The difference between roasted stem and leaf tea derived from the same tea plants were investigated using GC-MS. Pyrazine compounds exhibited a roasted odour and high flavour dilution (FD) factors, as determined via AEDA. Roasted stem tea was richer in these pyrazines than roasted leaf tea. Geraniol and linalool exhibited high FD factors and a floral odour, and roasted stem tea was richer in these compounds than roasted leaf tea. These results may have a positive impact on the development of tea products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Moraxella species are primarily responsible for generating malodor in laundry.

PubMed

Kubota, Hiromi; Mitani, Asako; Niwano, Yu; Takeuchi, Kohei; Tanaka, Atsushi; Yamaguchi, Noriko; Kawamura, Yoshiaki; Hitomi, Jun

2012-05-01

Many people in Japan often detect an unpleasant odor generated from laundry that is hung to dry indoors or when using their already-dried laundry. Such an odor is often described as a "wet-and-dirty-dustcloth-like malodor" or an "acidic or sweaty odor." In this study, we isolated the major microorganisms associated with such a malodor, the major component of which has been identified as 4-methyl-3-hexenoic acid (4M3H). The isolates were identified as Moraxella osloensis by morphological observation and biochemical and phylogenetic tree analyses. M. osloensis has the potential to generate 4M3H in laundry. The bacterium is known to cause opportunistic infections but has never been known to generate a malodor in clothes. We found that M. osloensis exists at a high frequency in various living environments, particularly in laundry in Japan. The bacterium showed a high tolerance to desiccation and UV light irradiation, providing one of the possible reasons why they survive in laundry during and even after drying.

Potential for reduction of odorous compounds in swine manure through diet modification.

PubMed

Sutton, A L; Kephart, K B; Verstegen, M W; Canh, T T; Hobbs, P J

1999-02-01

Recent public concern about air pollution from pork production units has prompted more research to develop methods to reduce and control odors. Masking agents, enzymes and bacterial preparations, feed additives, chemicals, oxidation processes, air scrubbers, biofilters, and new ventilation systems have been studied. Research relating the effects of the swine diet on manure odors has been scarce. Introducing feed additives to bind ammonia, change digesta pH, affect specific enzyme activity, and mask odors has been either costly or not consistently successful. Recent research emphasis has focused on manipulating the diet 1) to increase the nutrient utilization of the diet to reduce excretion products, 2) to enhance microbial metabolism in the lower digestive tract to reduce excretion of odor-causing compounds, and 3) to change the physical characteristics of urine and feces to reduce odor emissions. Primary odor-causing compounds evolve from excess degradable proteins and lack of specific fermentable carbohydrates during microbial fermentation. Reductions in ammonia emissions by 28 to 79% through diet modifications have been reported. Limited research on reduction of other odorous volatile organic compounds through diet modifications is promising. Use of synthetic amino acids with reduced intact protein levels in diets significantly reduces nitrogen excretions and odor production. Addition of nonstarch polysaccharides and specific oligosaccharides further alters the pathway of nitrogen excretion and reduces odor emission. Continued nutritional and microbial research to incorporate protein degradation products, especially sulfur-containing organics, with fermentable carbohydrates in the lower gastrointestinal tract of pigs will further control odors from manure.

Pavlovian conditioning enhances resistance to disruption of dogs performing an odor discrimination.

PubMed

Hall, Nathaniel J; Smith, David W; Wynne, Clive D L

2015-05-01

Domestic dogs are used to aid in the detection of a variety of substances such as narcotics and explosives. Under real-world detection situations there are many variables that may disrupt the dog's performance. Prior research on behavioral momentum theory suggests that higher rates of reinforcement produce greater resistance to disruption, and that this is heavily influenced by the stimulus-reinforcer relationship. The present study tests the Pavlovian interpretation of resistance to change using dogs engaged in an odor discrimination task. Dogs were trained on two odor discriminations that alternated every six trials akin to a multiple schedule in which the reinforcement probability for a correct response was always 1. Dogs then received several sessions of either odor Pavlovian conditioning to the S+ of one odor discrimination (Pavlovian group) or explicitly unpaired exposure to the S+ of one odor discrimination (Unpaired group). The remaining odor discrimination pair for each dog always remained an unexposed control. Resistance to disruption was assessed under presession feeding, a food-odor disruptor condition, and extinction, with baseline sessions intervening between disruption conditions. Equivalent baseline detection rates were observed across experimental groups and odorant pairs. Under disruption conditions, Pavlovian conditioning led to enhanced resistance to disruption of detection performance compared to the unexposed control odor discrimination. Unpaired odor conditioning did not influence resistance to disruption. These results suggest that changes in Pavlovian contingencies are sufficient to influence resistance to change. © Society for the Experimental Analysis of Behavior.

Functional magnetic resonance imaging in awake transgenic fragile X rats: evidence of dysregulation in reward processing in the mesolimbic/habenular neural circuit.

PubMed

Kenkel, W M; Yee, J R; Moore, K; Madularu, D; Kulkarni, P; Gamber, K; Nedelman, M; Ferris, C F

2016-03-22

Anxiety and social deficits, often involving communication impairment, are fundamental clinical features of fragile X syndrome. There is growing evidence that dysregulation in reward processing is a contributing factor to the social deficits observed in many psychiatric disorders. Hence, we hypothesized that transgenic fragile X mental retardation 1 gene (fmr1) KO (FX) rats would display alterations in reward processing. To this end, awake control and FX rats were imaged for changes in blood oxygen level dependent (BOLD) signal intensity in response to the odor of almond, a stimulus to elicit the innate reward response. Subjects were 'odor naive' to this evolutionarily conserved stimulus. The resulting changes in brain activity were registered to a three-dimensional segmented, annotated rat atlas delineating 171 brain regions. Both wild-type (WT) and FX rats showed robust brain activation to a rewarding almond odor, though FX rats showed an altered temporal pattern and tended to have a higher number of voxels with negative BOLD signal change from baseline. This pattern of greater negative BOLD was especially apparent in the Papez circuit, critical to emotional processing and the mesolimbic/habenular reward circuit. WT rats showed greater positive BOLD response in the supramammillary area, whereas FX rats showed greater positive BOLD response in the dorsal lateral striatum, and greater negative BOLD response in the retrosplenial cortices, the core of the accumbens and the lateral preoptic area. When tested in a freely behaving odor-investigation paradigm, FX rats failed to show the preference for almond odor which typifies WT rats. However, FX rats showed investigation profiles similar to WT when presented with social odors. These data speak to an altered processing of this highly salient novel odor in the FX phenotype and lend further support to the notion that altered reward systems in the brain may contribute to fragile X syndrome symptomology.

Odorous House Ants (Tapinoma sessile) as Back-Seat Drivers of Localized Ant Decline in Urban Habitats

PubMed Central

Salyer, Adam; Bennett, Gary W.; Buczkowski, Grzegorz A.

2014-01-01

Invasive species and habitat disturbance threaten biodiversity worldwide by modifying ecosystem performance and displacing native organisms. Similar homogenization impacts manifest locally when urbanization forces native species to relocate or reinvade perpetually altered habitat. This study investigated correlations between ant richness and abundance in response to urbanization and the nearby presence of invasive ant species, odorous house ants (Tapinoma sessile), within its native region. Surveying localized ant composition within natural, semi-natural, and urban habitat supported efforts to determine whether T. sessile appear to be primary (drivers) threats as instigators or secondary (passengers) threats as inheritors of indigenous ant decline. Sampling 180 sites, evenly split between all habitats with and without T. sessile present, yielded 45 total species. Although urbanization and T. sessile presence factors were significantly linked to ant decline, their interaction correlated to the greatest reduction of total ant richness (74%) and abundance (81%). Total richness appeared to decrease from 27 species to 18 when natural habitat is urbanized and from 18 species to 7 with T. sessile present in urban plots. Odorous house ant presence minimally influenced ant communities within natural and semi-natural habitat, highlighting the importance of habitat alteration and T. sessile presence interactions. Results suggest urbanization releases T. sessile from unknown constraints by decreasing ant richness and competition. Within urban environment, T. sessile are pre-adapted to quickly exploit new resources and grow to supercolony strength wherein T. sessile drive adjacent biodiversity loss. Odorous house ants act as passengers and drivers of ecological change throughout different phases of urban ‘invasion’. This progression through surviving habitat alteration, exploiting new resources, thriving, and further reducing interspecific competition supports a “back-seat driver” role and affects pest management strategies. As demonstrated by T. sessile, this article concludes native species can become back-seat drivers of biodiversity loss and potentially thrive as “metro-invasive” species. PMID:25551819

Children's hedonic judgments of cigarette smoke odor: effects of parental smoking and maternal mood.

PubMed

Forestell, Catherine A; Mennella, Julie A

2005-12-01

Age-appropriate tasks were used to assess 3- to 8-year-old children's liking, identification, and preference for a variety of odors, including that of exhaled cigarette smoke. Children whose parents smoke took longer to decide whether they liked the cigarette odor and were significantly more likely to prefer the odor of cigarette to the neutral and unfamiliar odor of green tea compared with children of nonsmokers. Among children of smokers, relative preferences for the cigarette odor were related to maternal mood disturbance and depression scores. These findings suggest that some early learning about cigarette smoke odor is based on sensory experiences at home and anchors it to the emotional context in which their mothers smoke. ((c) 2005 APA, all rights reserved).

An odor flux model for cattle feedlots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ormerod, R.J.

1994-12-31

Odor nuisance associated with cattle feedlots has been an issue of major interest and concern to regulators, rural communities and the beef industry in Australia over the past decade. Methods of assessing the likely impacts of new feedlots on community odor exposure are still being developed, but in the past few years much has been learnt about the processes of odor generation, flux and dispersion as well as the acceptability of feedlot odor to exposed communities. This paper outlines a model which simulates the complex physical and chemical processes leading to odor emissions in a simple and practical framework. Themore » model, named BULSMEL, has been developed as a response to regulatory requirements for quantitative assessments of odor impact. It will continue to be refined as more data are gathered.« less

Odor detection of mixtures of homologous carboxylic acids and coffee aroma compounds by humans.

PubMed

Miyazawa, Toshio; Gallagher, Michele; Preti, George; Wise, Paul M

2009-11-11

Mixture summation among homologous carboxylic acids, that is, the relationship between detection probabilities for mixtures and detection probabilities for their unmixed components, varies with similarity in carbon-chain length. The current study examined detection of acetic, butyric, hexanoic, and octanoic acids mixed with three other model odorants that differ greatly from the acids in both structure and odor character, namely, 2-hydroxy-3-methylcyclopent-2-en-1-one, furan-2-ylmethanethiol, and (3-methyl-3-sulfanylbutyl) acetate. Psychometric functions were measured for both single compounds and binary mixtures (2 of 5, forced-choice method). An air dilution olfactometer delivered stimuli, with vapor-phase calibration using gas chromatography-mass spectrometry. Across the three odorants that differed from the acids, acetic and butyric acid showed approximately additive (or perhaps even supra-additive) summation at low perithreshold concentrations, but subadditive interactions at high perithreshold concentrations. In contrast, the medium-chain acids showed subadditive interactions across a wide range of concentrations. Thus, carbon-chain length appears to influence not only summation with other carboxylic acids but also summation with at least some unrelated compounds.

Characterization of gaseous odorous emissions from a rendering plant by GC/MS and treatment by biofiltration.

PubMed

Anet, Benoît; Lemasle, Marguerite; Couriol, Catherine; Lendormi, Thomas; Amrane, Abdeltif; Le Cloirec, Pierre; Cogny, Gilles; Fillières, Romain

2013-10-15

This research focuses on the identification and quantification of odorous components in rendering plant emissions by GC/MS and other analytical methods, as well as the description of phenomena occurring in biofilter in order to improve the removal efficiency of industrial biofilters. Among the 36 compounds quantified in the process air stream, methanethiol, isopentanal and hydrogen sulfide, presented the major odorous contributions according to their high concentrations, generally higher than 10 mg m(-3), and their low odorous detection thresholds. The elimination of such component mixtures by biofiltration (Peat packing material, EBRT: 113 s) was investigated and revealed that more than 83% of hydrogen sulfide and isopentanal were removed by biofilter. Nevertheless, the incomplete degradation of such easily degradable pollutants suggested inappropriate conditions as lack of nutrients and acidic pH. These inadequate conditions could explain the lack of performance, especially observed on methanethiol (53% of RE) and the production of oxygenated and sulfur by-products by the biofilter itself. Copyright © 2013. Published by Elsevier Ltd.

Mexico City air pollution adversely affects olfactory function and intranasal trigeminal sensitivity.

PubMed

Guarneros, Marco; Hummel, Thomas; Martínez-Gómez, Margaríta; Hudson, Robyn

2009-11-01

Surprisingly little is known about the effects of big-city air pollution on olfactory function and even less about its effects on the intranasal trigeminal system, which elicits sensations like burning, stinging, pungent, or fresh and contributes to the overall chemosensory experience. Using the Sniffin' Sticks olfactory test battery and an established test for intranasal trigeminal perception, we compared the olfactory performance and trigeminal sensitivity of residents of Mexico City, a region with high air pollution, with the performance of a control population from the Mexican state of Tlaxcala, a geographically comparable but less polluted region. We compared the ability of 30 young adults from each location to detect a rose-like odor (2-phenyl ethanol), to discriminate between different odorants, and to identify several other common odorants. The control subjects from Tlaxcala detected 2-phenyl ethanol at significantly lower concentrations than the Mexico City subjects, they could discriminate between odorants significantly better, and they performed significantly better in the test of trigeminal sensitivity. We conclude that Mexico City air pollution impairs olfactory function and intranasal trigeminal sensitivity, even in otherwise healthy young adults.

Individual Differences in Verbal and Non-Verbal Affective Responses to Smells: Influence of Odor Label Across Cultures.

PubMed

Ferdenzi, Camille; Joussain, Pauline; Digard, Bérengère; Luneau, Lucie; Djordjevic, Jelena; Bensafi, Moustafa

2017-01-01

Olfactory perception is highly variable from one person to another, as a function of individual and contextual factors. Here, we investigated the influence of 2 important factors of variation: culture and semantic information. More specifically, we tested whether cultural-specific knowledge and presence versus absence of odor names modulate odor perception, by measuring these effects in 2 populations differing in cultural background but not in language. Participants from France and Quebec, Canada, smelled 4 culture-specific and 2 non-specific odorants in 2 conditions: first without label, then with label. Their ratings of pleasantness, familiarity, edibility, and intensity were collected as well as their psychophysiological and olfactomotor responses. The results revealed significant effects of culture and semantic information, both at the verbal and non-verbal level. They also provided evidence that availability of semantic information reduced cultural differences. Semantic information had a unifying action on olfactory perception that overrode the influence of cultural background. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Characterization of volatiles and identification of odor-active compounds of rocket leaves.

PubMed

Raffo, Antonio; Masci, Maurizio; Moneta, Elisabetta; Nicoli, Stefano; Sánchez Del Pulgar, José; Paoletti, Flavio

2018-02-01

The volatile profile of crushed rocket leaves (Eruca sativa and Diplotaxis tenuifolia) was investigated by applying Headspace Solid-Phase MicroExtraction (HS-SPME), combined with GC-MS, to an aqueous extract obtained by homogenization of rocket leaves, and stabilized by addition of CaCl 2 . A detailed picture of volatile products of the lipoxygenase pathway (mainly C6-aldehydes) and of glucosinolate hydrolysis (mainly isothiocyanates), and their dynamics of formation after tissue disruption was given. Odor-active compounds of leaves were characterized by GC-Olfactometry (GC-O) and Aroma Extract Dilution Analysis (AEDA): volatile isolates obtained by HS-SPME from an aqueous extract and by Stir-Bar Sorptive Extraction (SBSE) from an ethanolic extract were analyzed. The most potent odor-active compounds fully or tentatively identified were (Z)- and (E)-3-hexenal, (Z)-1,5-octadien-3-one, responsible for green olfactory notes, along with 4-mercaptobutyl and 4-(methylthio)butyl isothiocyanate, associated with typical rocket and radish aroma. Relatively high odor potency was observed for 1-octen-3-one, (E)-2-octenal and 1-penten-3-one. Copyright © 2017 Elsevier Ltd. All rights reserved.

Olfactory Sensitivity for Six Predator Odorants in CD-1 Mice, Human Subjects, and Spider Monkeys

PubMed Central

Sarrafchi, Amir; Odhammer, Anna M. E.; Hernandez Salazar, Laura Teresa; Laska, Matthias

2013-01-01

Using a conditioning paradigm, we assessed the olfactory sensitivity of six CD-1 mice (Mus musculus) for six sulfur-containing odorants known to be components of the odors of natural predators of the mouse. With all six odorants, the mice discriminated concentrations <0.1 ppm (parts per million) from the solvent, and with five of the six odorants the best-scoring animals were even able to detect concentrations <1 ppt (parts per trillion). Four female spider monkeys (Ateles geoffroyi) and twelve human subjects (Homo sapiens) tested in parallel were found to detect the same six odorants at concentrations <0.01 ppm, and with four of the six odorants the best-scoring animals and subjects even detected concentrations <10 ppt. With all three species, the threshold values obtained here are generally lower than (or in the lower range of) those reported for other chemical classes tested previously, suggesting that sulfur-containing odorants may play a special role in olfaction. Across-species comparisons showed that the mice were significantly more sensitive than the human subjects and the spider monkeys with four of the six predator odorants. However, the human subjects were significantly more sensitive than the mice with the remaining two odorants. Human subjects and spider monkeys significantly differed in their sensitivity with only two of the six odorants. These comparisons lend further support to the notion that the number of functional olfactory receptor genes or the relative or absolute size of the olfactory bulbs are poor predictors of a species’ olfactory sensitivity. Analysis of odor structure–activity relationships showed that in both mice and human subjects the type of alkyl rest attached to a thietane and the type of oxygen moiety attached to a thiol significantly affected olfactory sensitivity. PMID:24278296

Odor impact assessment of trace sulfur compounds from working faces of landfills in Beijing, China.

PubMed

Liu, Yanjun; Lu, Wenjing; Wang, Hongtao; Huang, Qifei; Gao, Xingbao

2018-08-15

Odor pollution from landfills is causing a growing number of public complaints and concerns. Compared with hydrogen sulfide (H 2 S) and ammonia (NH 3 ), odor impacts of trace sulfur compounds (TSCs) are arousing concerns due to their low odor threshold values (OTVs). Working face on landfill sites has been claimed as major source of odor impacts. This study estimated the odor impacts of fugitive TSCs from the working face of a large typical municipal solid waste (MSW) landfill in Beijing, China. A modified wind tunnel system was introduced to estimate emission rates of TSCs, which is a basic requirement for odor impact assessment. The odor activity value (OAV) method was introduced for odor evaluation. Fieldwork in the selected landfill was conducted from 2014 to 2015. Methyl mercaptan (CH 3 SH), dimethyl sulfide, dimethyl disulfide (DMDS), and carbon disulfide (CS 2 ) were the TSCs studied in this work. The spatial concentration distributions of the TSCs were calculated on the basis of the Gaussian dispersion model in a "normal case" scenario and a "worst case" scenario. DMDS showed the highest emission rate (7.18 μg m -2  s -1 ), and CH 3 SH was the dominant odorous compound with an average emission rate of 4.58 μg m -2  s -1 . The dispersion modeling indicated that the odor impact distances of the TSCs in the studied landfill for the normal case and worst case scenarios were 495 ± 96 m and 9230 m at the downwind regions, respectively. Results of this study can benefit the formulation of strategies for odor control and abatement in landfill sites. Copyright © 2018 Elsevier Ltd. All rights reserved.

Odors and Sensations of Humidity and Dryness in Relation to Sick Building Syndrome and Home Environment in Chongqing, China

PubMed Central

Wang, Juan; Li, Baizhan; Yang, Qin; Yu, Wei; Wang, Han; Norback, Dan; Sundell, Jan

2013-01-01

The prevalence of perceptions of odors and sensations of air humidity and sick building syndrome symptoms in domestic environments were studied using responses to a questionnaire on the home environment. Parents of 4530 1–8 year old children from randomly selected kindergartens in Chongqing, China participated. Stuffy odor, unpleasant odor, pungent odor, mold odor, tobacco smoke odor, humid air and dry air in the last three month (weekly or sometimes) was reported by 31.4%, 26.5%, 16.1%, 10.6%, 33.0%, 32.1% and 37.2% of the parents, respectively. The prevalence of parents’ SBS symptoms (weekly or sometimes) were: 78.7% for general symptoms, 74.3% for mucosal symptoms and 47.5% for skin symptoms. Multi-nominal regression analyses for associations between odors/sensations of air humidity and SBS symptoms showed that the odds ratio for “weekly” SBS symptoms were consistently higher than for “sometimes” SBS symptoms. Living near a main road or highway, redecoration, and new furniture were risk factors for perceptions of odors and sensations of humid air and dry air. Dampness related problems (mold spots, damp stains, water damage and condensation) were all risk factors for perceptions of odors and sensations of humid air and dry air, as was the presence of cockroaches, rats, and mosquitoes/flies, use of mosquito-repellent incense and incense. Protective factors included cleaning the child’s bedroom every day and frequently exposing bedding to sunshine. In conclusion, adults’ perceptions of odors and sensations of humid air and dry air are related to factors of the home environment and SBS symptoms are related to odor perceptions. PMID:23991107

Diagnostic Value of the Impairment of Olfaction in Parkinson's Disease

PubMed Central

Casjens, Swaantje; Eckert, Angelika; Woitalla, Dirk; Ellrichmann, Gisa; Turewicz, Michael; Stephan, Christian; Eisenacher, Martin; May, Caroline; Meyer, Helmut E.; Brüning, Thomas; Pesch, Beate

2013-01-01

Background Olfactory impairment is increasingly recognized as an early symptom in the development of Parkinson's disease. Testing olfactory function is a non-invasive method but can be time-consuming which restricts its application in clinical settings and epidemiological studies. Here, we investigate odor identification as a supportive diagnostic tool for Parkinson's disease and estimate the performance of odor subsets to allow a more rapid testing of olfactory impairment. Methodology/Principal Findings Odor identification was assessed with 16 Sniffin' sticks in 148 Parkinson patients and 148 healthy controls. Risks of olfactory impairment were estimated with proportional odds models. Random forests were applied to classify Parkinson and non-Parkinson patients. Parkinson patients were rarely normosmic (identification of more than 12 odors; 16.8%) and identified on average seven odors whereas the reference group identified 12 odors and showed a higher prevalence of normosmy (31.1%). Parkinson patients with rigidity dominance had a twofold greater prevalence of olfactory impairment. Disease severity was associated with impairment of odor identification (per score point of the Hoehn and Yahr rating OR 1.87, 95% CI 1.26–2.77). Age-related impairment of olfaction showed a steeper gradient in Parkinson patients. Coffee, peppermint, and anise showed the largest difference in odor identification between Parkinson patients and controls. Random forests estimated a misclassification rate of 22.4% when comparing Parkinson patients with healthy controls using all 16 odors. A similar rate (23.8%) was observed when only the three aforementioned odors were applied. Conclusions/Significance Our findings indicate that testing odor identification can be a supportive diagnostic tool for Parkinson's disease. The application of only three odors performed well in discriminating Parkinson patients from controls, which can facilitate a wider application of this method as a point-of-care test. PMID:23696904

Default Mode Network (DMN) Deactivation during Odor-Visual Association

PubMed Central

Karunanayaka, Prasanna R.; Wilson, Donald A.; Tobia, Michael J.; Martinez, Brittany; Meadowcroft, Mark; Eslinger, Paul J.; Yang, Qing X.

2017-01-01

Default mode network (DMN) deactivation has been shown to be functionally relevant for goal-directed cognition. In this study, we investigated the DMN’s role during olfactory processing using two complementary functional magnetic resonance imaging (fMRI) paradigms with identical timing, visual-cue stimulation and response monitoring protocols. Twenty-nine healthy, non-smoking, right-handed adults (mean age = 26±4 yrs., 16 females) completed an odor-visual association fMRI paradigm that had two alternating odor+visual and visual-only trial conditions. During odor+visual trials, a visual cue was presented simultaneously with an odor, while during visual-only trial conditions the same visual cue was presented alone. Eighteen of the 29 participants (mean age = 27.0 ± 6.0 yrs.,11 females) also took part in a control no-odor fMRI paradigm that consisted of visual-only trial conditions which were identical to the visual-only trials in the odor-visual association paradigm. We used Independent Component Analysis (ICA), extended unified structural equation modeling (euSEM), and psychophysiological interaction (PPI) to investigate the interplay between the DMN and olfactory network. In the odor-visual association paradigm, DMN deactivation was evoked by both the odor+visual and visual-only trial conditions. In contrast, the visual-only trials in the no-odor paradigm did not evoke consistent DMN deactivation. In the odor-visual association paradigm, the euSEM and PPI analyses identified a directed connectivity between the DMN and olfactory network which was significantly different between odor+visual and visual-only trial conditions. The results support a strong interaction between the DMN and olfactory network and highlights DMN’s role in task-evoked brain activity and behavioral responses during olfactory processing. PMID:27785847

Basic emotions evoked by eugenol odor differ according to the dental experience. A neurovegetative analysis.

PubMed

Robin, O; Alaoui-Ismaïli, O; Dittmar, A; Vernet-Maury, E

1999-06-01

Subjective individual experiences seem to indicate that odors may form strong connections with memories, especially those charged with emotional significance. In the dental field, this could be the case with the odorant eugenol, responsible for the typical clinging odor impregnating the dental office. The odor of eugenol could evoke memories of unpleasant dental experiences and, therefore, negative feelings such as anxiety and fear, since eugenates (cements containing eugenol) are used in potentially painful restorative dentistry. This hypothesis was tested by evaluating the emotional impact of the odor of eugenol through autonomic nervous system (ANS) analysis. The simultaneous variations of six ANS parameters (two electrodermal, two thermovascular and two cardiorespiratory), induced by the inhalation of this odorant, were recorded on volunteer subjects. Vanillin (a pleasant odorant) and propionic acid (an unpleasant one) served as controls. After the experiment, subjects were asked to rate the pleasantness versus unpleasantness of each odorant on an 11-point hedonic scale. The patterns of autonomic responses, obtained for each odorant and each subject, were transcribed into one of the six basic emotions defined by Ekman et al. (happiness, surprise, sadness, fear, anger and disgust). Results were compared between two groups of subjects divided according to their dental experience (fearful and non-fearful dental care subjects) and showed significant differences only for eugenol. This odorant was rated as pleasant by non-fearful dental subjects but unpleasant by fearful dental subjects. The evoked autonomic responses were mainly associated with positive basic emotions (happiness and surprise) in non-fearful dental subjects and with negative basic emotions (fear, anger, disgust) in fearful dental subjects. These results suggest that eugenol can be responsible for different emotional states depending on the subjects' dental experience, which seems to confirm the potential role of odors as elicitors of emotional memories. This study also supports the possible influence of the ambient odor impregnating the dental office, strengthening a negative conditioning toward dental care in some anxious patients.

Neural correlates of social odor recognition and the representation of individual distinctive social odors within entorhinal cortex and ventral subiculum.

PubMed

Petrulis, A; Alvarez, P; Eichenbaum, H

2005-01-01

Recognition of individual conspecifics is important for social behavior and requires the formation of memories for individually distinctive social signals. Individual recognition is often mediated by olfactory cues in mammals, especially nocturnal rodents such as golden hamsters. In hamsters, this form of recognition requires main olfactory system input to the lateral entorhinal cortex (LEnt). Here, we tested whether neurons in LEnt and the nearby ventral subiculum (VS) would show cellular correlates of this natural form of recognition memory. Two hundred ninety single neurons were recorded from both superficial (SE) and deep layers of LEnt (DE) and VS while male hamsters investigated volatile odorants from female vaginal secretions. Many neurons encoded differences between female's odors with many discriminating between odors from different individual females but not between different odor samples from the same female. Other neurons discriminated between odor samples from one female and generalized across collections from other females. LEnt and VS neurons showed enhanced or suppressed cellular activity during investigation of previously presented odors and in response to novel odors. A majority of SE neurons decreased firing to odor repetition and increased activity to novel odors. In contrast, DE neurons often showed suppressed activity in response to novel odors. Thus, neurons in LEnt and VS of male hamsters encode information that is critical for the identification and recognition of individual females by odor cues. This study reveals cellular mechanisms in LEnt and VS that may mediate a natural form of recognition memory in hamsters. These neuronal responses were similar to those observed in rats and monkeys during performance in standard recognition memory tasks. Consequently, the present data extend our understanding of the cellular basis for recognition memory and suggest that individual recognition requires similar neural mechanisms as those employed in laboratory tests of recognition memory.

CONTROLLING ODOROUS EMISSIONS FROM IRON FOUNDRIES

EPA Science Inventory

The report discusses the control of odorous emissions from iron foundries. he main process sources of odors in iron foundries are mold and core making, casting, and sand shakeout. he odors are usually caused by chemicals, which may be present as binders and other additives to the...

Predator odor avoidance as a rodent model of anxiety: learning-mediated consequences beyond the initial exposure.

PubMed

Staples, Lauren G

2010-11-01

Prey animals such as rats display innate defensive responses when exposed to the odor of a predator, providing a valuable means of studying the neurobiology of anxiety. While the unconditioned behavioral and neural responses to a single predator odor exposure have been well documented, the paradigm can also be used to study learning-dependent adaptations that occur following repeated exposure to a stressor or associated stimuli. In developing preclinical models for human anxiety disorders this is advantageous, as anxiety disorders seldom involve a single acute experience of anxiety, but rather are chronic and/or recurring illnesses. Part 1 of this review summarizes current research on the three most commonly used predator-related odors: cat odor, ferret odor, and trimethylthiazoline (a component of fox odor). Part 2 reviews the learning-based behavioral and neural adaptations that underlie predator odor-induced context conditioning, one-trial tolerance, sensitization, habituation and dishabituation. Copyright © 2010 Elsevier Inc. All rights reserved.

Olfactometric determination of the most potent odor-active compounds in salmon muscle (Salmo salar) smoked by using four smoke generation techniques.

PubMed

Varlet, Vincent; Serot, Thierry; Cardinal, Mireille; Knockaert, Camille; Prost, Carole

2007-05-30

The volatile compounds of salmon fillets smoked according to four smoked generation techniques (smoldering, thermostated plates, friction, and liquid smoke) were investigated. The main odor-active compounds were identified by gas chromatography coupled with olfactometry and mass spectrometry. Only the odorant volatile compounds detected by at least six judges (out of eight) were identified as potent odorants. Phenolic compounds and guaiacol derivatives were the most detected compounds in the olfactometric profile whatever the smoking process and could constitute the smoky odorant skeleton of these products. They were recovered in the aromatic extracts of salmon smoked by smoldering and by friction, which were characterized by 18 and 25 odor-active compounds, respectively. Furannic compounds were more detected in products smoked with thermostated plates characterized by 26 odorants compounds. Finally, the 27 odorants of products treated with liquid smoke were significantly different from the three others techniques applying wood pyrolysis because pyridine derivatives and lipid oxidation products were perceived in the aroma profile.

Controlling VOCs and odor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zmuda, J.

1994-07-01

Few environmental issues attract more attention than odor emissions. The odor source can quickly be identified, coming under immediate public scrutiny. Often, odor is not merely a public nuisance problem but can be indicative of volatile organic compound (VOC) control needs at the facility. In some cases, odor-producing compounds are VOCs regulated under different sections of federal, state or local law. Specific requirements for VOC or odor control depend on many factors, including the source and nature of the emissions, the quantity of emissions and the location of the facility. Many states impose specific odor-control requirements, in addition to themore » regulations of the Clean Air Act Amendments of 1990 (CAAA), under which odor-causing emissions may be regulated under Titles 1 and/or 3. Under Title 1, the non-attainment title, facilities located in major metropolitan areas not in attainment of the National Ambient Air Quality Standards (NAAQS) for ozone likely will be required to reduce emissions of VOCs.« less

Odor intensity and characterization of jet exhaust and chemical analytical measurements

NASA Technical Reports Server (NTRS)

Kendall, D. A.; Levins, P. L.

1973-01-01

Odor and chemical analyses were carried out on the exhaust samples from a J-57 combustor can operated over a range of inlet conditions, and with several fuel types and nozzle modifications. The odor characteristics and total intensity of odor for each exhaust were determined over a range of dilutions to allow for a least squares determination of the intensity at 1,000 to 1 dilutions. Analytical measures included the concentration of total hydrocarbons and the concentrations of aromatic organic species and oxygenated organic species from collected samples which were taken concurrently. A correlation was found between the concentration of the odorous oxygenated fraction and the total intensity of aroma. Inlet operating conditions and nozzle modifications which increase the efficiency of combustion as measured by exhaust gas analyses reduce the odor intensity and the quantity of oxygenates in the exhaust. The type of fuel burned altered the intensity of odor in relation to the quantity of oxygenates produced and, in some instances, changed the odor character.

Odor-active constituents in fresh pineapple (Ananas comosus [L.] Merr.) by quantitative and sensory evaluation.

PubMed

Tokitomo, Yukiko; Steinhaus, Martin; Büttner, Andrea; Schieberle, Peter

2005-07-01

By application of aroma extract dilution analysis (AEDA) to an aroma distillate prepared from fresh pineapple using solvent-assisted flavor evaporation (SAFE), 29 odor-active compounds were detected in the flavor dilution (FD) factor range of 2 to 4,096. Quantitative measurements performed by stable isotope dilution assays (SIDA) and a calculation of odor activity values (OAVs) of 12 selected odorants revealed the following compounds as key odorants in fresh pineapple flavor: 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDF; sweet, pineapple-like, caramel-like), ethyl 2-methylpropanoate (fruity), ethyl 2-methylbutanoate (fruity) followed by methyl 2-methylbutanoate (fruity, apple-like) and 1-(E,Z)-3,5-undecatriene (fresh, pineapple-like). A mixture of these 12 odorants in concentrations equal to those in the fresh pineapple resulted in an odor profile similar to that of the fresh juice. Furthermore, the results of omission tests using the model mixture showed that HDF and ethyl 2-methylbutanoate are character impact odorants in fresh pineapple.

Identification and characterization of odorous gas emission from a full-scale food waste anaerobic digestion plant in China.

PubMed

Kong, Xin; Liu, Jianguo; Ren, Lianhai; Song, Minying; Wang, Xiaowei; Ni, Zhe; Nie, Xiaoqin

2015-10-01

Odorous gas emission characteristic along with the successive processes of a typical full-scale food waste (FW) anaerobic digestion plant in China was investigated in September and January. Seasonal variations in pollutant concentration and principal component analysis (PCA) showed markedly different characteristics between the two months. However, the main reason for the seasonal difference at the sorting process differed from the reason for the seasonal difference at other treatment units. Most odorous volatile organic compound (VOC) concentrations tested near an anaerobic digestion tank were similar and low in both months. Odor indices, including odor contribution (OC) and odor activity value (OAV) of various odorants, were further calculated to evaluate the malodor degree and contribution to the nuisance smell of any odorant. Brought about by people's different dietary habits, H2S and sulfocompounds were found to be dominant contributors to the large total OVA in the January test. By contrast, oxygenated organic compounds played an important role on the sum of OVA in September.

Odor identity coding by distributed ensembles of neurons in the mouse olfactory cortex

PubMed Central

Roland, Benjamin; Deneux, Thomas; Franks, Kevin M; Bathellier, Brice; Fleischmann, Alexander

2017-01-01

Olfactory perception and behaviors critically depend on the ability to identify an odor across a wide range of concentrations. Here, we use calcium imaging to determine how odor identity is encoded in olfactory cortex. We find that, despite considerable trial-to-trial variability, odor identity can accurately be decoded from ensembles of co-active neurons that are distributed across piriform cortex without any apparent spatial organization. However, piriform response patterns change substantially over a 100-fold change in odor concentration, apparently degrading the population representation of odor identity. We show that this problem can be resolved by decoding odor identity from a subpopulation of concentration-invariant piriform neurons. These concentration-invariant neurons are overrepresented in piriform cortex but not in olfactory bulb mitral and tufted cells. We therefore propose that distinct perceptual features of odors are encoded in independent subnetworks of neurons in the olfactory cortex. DOI: http://dx.doi.org/10.7554/eLife.26337.001 PMID:28489003

Chemosensory Dysfunction in Alcohol-Related Disorders: A Joint Exploration of Olfaction and Taste.

PubMed

Brion, Mélanie; de Timary, Philippe; Vander Stappen, Caroline; Guettat, Lamia; Lecomte, Benoît; Rombaux, Philippe; Maurage, Pierre

2015-11-01

Chemosensory (olfaction-taste) dysfunctions are considered as reliable biomarkers in many neurological and psychiatric states. However, experimental measures of chemosensory abilities are lacking in alcohol-dependence (AD) and Korsakoff Syndrome (KS, a neurological complication of AD), despite the role played by alcohol-related odors and taste in the emergence and maintenance of AD. This study thus investigated chemosensory impairments in AD and KS. Olfactory-gustatory measures were taken among 20 KS, 20 AD, and 20 control participants. Olfaction (odor detection-discrimination-identification) was assessed using the "Sniffin Sticks" battery and taste was measured using the "Taste Strips" task. Impairments were found for high-level olfaction in AD (odor discrimination) and KS (odor discrimination-identification), even after controlling for psychopathological comorbidities. Gustatory deficits were also observed in both groups, indexing a global deficit for chemosensory perception. Finally, the gradient of impairment between the successive disease stages for odor identification suggests that the hypothesis of a continuum between AD and KS regarding cognitive deficits can be generalized to chemosensory perception. AD and KS are thus characterized by deficits in chemosensory abilities, which could constitute a marker of the AD-KS transition. In view of its deleterious influence on everyday life, chemosensory dysfunction should also be taken into account in clinical settings. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Smelling Anxiety Chemosignals Impairs Clinical Performance of Dental Students.

PubMed

Singh, Preet Bano; Young, Alix; Lind, Synnøve; Leegaard, Marie Cathinka; Capuozzo, Alessandra; Parma, Valentina

2018-05-15

Despite the fact that human body odors can transfer anxiety-related signals, the impact of such signals in real-life situations is scant. In this study, the effects of anxiety chemosignals on the performance of dental students operating on simulation units, wearing t-shirts imbued with human sweat and masked with eugenol were tested. Twenty-four 4th year dental students (17F) donated their body odors in two sessions (Anxiety and Rest). Twenty-four normosmic, sex- and age-matched test subjects who were3rd year dental students performed three dental procedures while smelling masked anxiety body odors, masked rest body odors or masker alone. The intensity and pleasantness ratings showed that the test subjects could not report perceptual differences between the odor conditions. When exposed to masked anxiety body odors the test subject's dental performance was significantly worse than when they were exposed to masked rest body odors and masker alone, indicating that their performance was modulated by exposure to the emotional tone of the odor. These findings call for a careful evaluation of the anxiety-inducing effects of body odors in performance-related tasks and provide the first ecological evaluation of human anxiety chemosignal communication.

Habitat odor can alleviate innate stress responses in mice.

PubMed

Matsukawa, Mutsumi; Imada, Masato; Aizawa, Shin; Sato, Takaaki

2016-01-15

Predatory odors, which can induce innate fear and stress responses in prey species, are frequently used in the development of animal models for several psychiatric diseases including post-traumatic stress disorder (PTSD) following a life-threatening event. We have previously shown that odors can be divided into at least three types; odors that act as (1) innate stressors, (2) as innate relaxants, or (3) have no innate effects on stress responses. Here, we attempted to verify whether an artificial odor, which had no innate effect on predatory odor-induced stress, could alleviate stress if experienced in early life as a habitat odor. In the current study, we demonstrated that the innate responses were changed to counteract stress following a postnatal experience. Moreover, we suggest that inhibitory circuits involved in stress-related neuronal networks and the concentrations of norepinephrine in the hippocampus may be crucial in alleviating stress induced by the predatory odor. Overall, these findings may be important for understanding the mechanisms involved in differential odor responses and also for the development of pharmacotherapeutic interventions that can alleviate stress in illnesses like PTSD. Copyright © 2015 Elsevier B.V. All rights reserved.

Gas Chromatography Analysis with Olfactometric Detection (GC-O) as a Useful Methodology for Chemical Characterization of Odorous Compounds

PubMed Central

Brattoli, Magda; Cisternino, Ezia; Dambruoso, Paolo Rosario; de Gennaro, Gianluigi; Giungato, Pasquale; Mazzone, Antonio; Palmisani, Jolanda; Tutino, Maria

2013-01-01

The gas chromatography-olfactometry (GC-O) technique couples traditional gas chromatographic analysis with sensory detection in order to study complex mixtures of odorous substances and to identify odor active compounds. The GC-O technique is already widely used for the evaluation of food aromas and its application in environmental fields is increasing, thus moving the odor emission assessment from the solely olfactometric evaluations to the characterization of the volatile components responsible for odor nuisance. The aim of this paper is to describe the state of the art of gas chromatography-olfactometry methodology, considering the different approaches regarding the operational conditions and the different methods for evaluating the olfactometric detection of odor compounds. The potentials of GC-O are described highlighting the improvements in this methodology relative to other conventional approaches used for odor detection, such as sensoristic, sensorial and the traditional gas chromatographic methods. The paper also provides an examination of the different fields of application of the GC-O, principally related to fragrances and food aromas, odor nuisance produced by anthropic activities and odorous compounds emitted by materials and medical applications. PMID:24316571

Dine or dash? Turbulence inhibits blue crab navigation in attractive-aversive odor plumes by altering signal structure encoded by the olfactory pathway.

PubMed

Weissburg, Marc; Atkins, Lorin; Berkenkamp, Kimberly; Mankin, Danielle

2012-12-01

Blue crabs can distinguish and navigate to attractive (food) odors even when aversive odors (injured crab metabolites) are released nearby. Blue crabs in these conditions detect the aversive odor and avoid it, but find the attractive source with nearly the same success rate as when the attractive source is presented alone. Spatially and temporally distinct odor filaments appear to signal to foragers that the two odor sources are not co-located, and hence navigating to the attractive odor entails an acceptable risk of predation. However, environmentally produced turbulence suppresses tracking by homogenizing the two odors; blue crabs fail to track to the attractive source when the aversive source is present, even though turbulence does not substantially inhibit tracking to the attractive source alone. Removal of sensory input from aesthetascs on the antennules, but not chemosensors on the legs, rescues navigation to attractive-aversive dual plumes in turbulent conditions. These results suggest that mixing in the natural environment may amplify the effects of predators by suppressing tracking to food odors when aversive cues are present, and that the olfactory pathway mediates the response.

Identification and characterization of volatile components causing the characteristic flavor in miso (Japanese fermented soybean paste) and heat-processed miso products.

PubMed

Kumazawa, Kenji; Kaneko, Shu; Nishimura, Osamu

2013-12-11

The aroma concentrates of two types of raw miso (traditional Japanese fermented soybean paste) were prepared by combining solid phase extraction (SPE) and solvent-assisted flavor evaporation (SAFE) techniques. The aroma extract dilution analysis (AEDA) applied to the volatile fraction revealed 39 odor-active peaks with FD factors between 4(1) and 4(8). Among the perceived odorants, 32 odorants were identified or tentatively identified from the 39 odor-active peaks, and the newly identified odorants for the miso were half of them. Furthermore, by comparison of the FD factors between the raw miso and heat-processed miso, it was found that one increasing odorant (methional) and three decreasing odorants (1-octen-3-one, (Z)-1,5-octadien-3-one, and trans-4,5-epoxy-(E)-2-decenal) contributed to the flavor change during the heat processing. This finding suggested that the flavor change in the raw miso during heat processing is attributed to relatively few odorant changes. In addition, it was assumed that the amino acids included in the miso have a significant influence on the remarkable disappearance of the three decreasing odorants.

No oral-cavity-only discrimination of purely olfactory odorants.

PubMed

Stephenson, Dejaimenay; Halpern, Bruce P

2009-02-01

The purely olfactory odorants coumarin, octanoic acid, phenylethyl alcohol, and vanillin had been found to be consistently identified when presented retronasally but could not be identified when presented oral-cavity only (OCO). However, OCO discrimination of these odorants was not tested. Consequently, it remained possible that the oral cavity trigeminal system might provide sufficient information to differentiate these purely olfactory odorants. To evaluate this, 20 participants attempted to discriminate vapor-phase coumarin, octanoic acid, phenylethyl alcohol, and vanillin and, as a control, the trigeminal stimulus peppermint extract, from their glycerin solvent, all presented OCO. None of the purely olfactory odorants could be discriminated OCO, but, as expected, peppermint extract was consistently discriminated. This inability to discriminate clarifies and expands the previous report of lack of OCO identification of purely olfactory odorants. Taken together with prior data, these results suggest that the oral cavity trigeminal system is fully unresponsive to these odorants in vapor phase and that coumarin, octanoic acid, phenylethyl alcohol, and vanillin are indeed purely olfactory stimuli. The OCO discrimination of peppermint extract demonstrated that the absence of discrimination for the purely olfactory odorants was odorant dependent and confirmed that the oral cavity trigeminal system will provide differential response information to some vapor-phase stimuli.

Body odor aldehyde reduction by acetic acid bacterial extract including enzymes: alcohol dehydrogenase and aldehyde dehydrogenase.

PubMed

Yoshioka, N; Kurata, K; Takahashi, T; Ariizumi, M; Mori, T; Fujisawa, H; Kameyama, N; Okuyama, Y

2018-06-13

Body odor is mainly caused by secreted sweat. Although sweat is almost odorless immediately after secretion, decomposition or denaturation of components contained in sweat by bacteria on the skin surface contributes to unpleasant body odor. Body odor is due to various substances and aldehydes are primarily detected in body odor [1-4]. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Male hamster preference for odors of female hamster vaginal discharges: studies of experiential and hormonal determinants.

PubMed

Gregory, E; Engel, K; Pfaff, D

1975-07-01

Male hamsters approach sources of odors from female hamster vaginal discharges and spend significantly more time around these odor sources than around control locations in the test box. This preference for female hamster vaginal odors appears in sexually inexperienced as well as experienced males, even in individuals isolated from females since the time of weaning. Castration significantly reduces the sex odor preference, and treatment with testosterone propionate partially restores it.

Alliesthesia is greater for odors of fatty foods than of non-fat foods.

PubMed

Plailly, Jane; Luangraj, Ninhda; Nicklaus, Sophie; Issanchou, Sylvie; Royet, Jean-Pierre; Sulmont-Rossé, Claire

2011-12-01

Alliesthesia is the modulation of the rewarding value of a stimulus according to the internal state (hungry or satiated). This study aimed to evaluate this phenomenon as a function of the nature of the stimulus (odors evoking edible and non-edible items, and the food odors evoking fatty and non-fat foods) and to compare the effectiveness of two reward evaluations (measures of pleasantness and appetence) to reveal alliesthesia. The results showed that both fatty and non-fat food odors were judged as less pleasant and less appetent when the subjects were satiated than when they were hungry, whereas no such difference was observed for non-food odors. There was a greater decrease in appetence than there was in pleasantness. Moreover, the decrease in appetence was greater for fatty than for non-fat food odors, whereas the decrease in pleasantness was similar for both fatty and non-fat food odors. Our study allows for the definition of a more comprehensive pattern of alliesthesia based on odor category. It demonstrates that alliesthesia is specific to food odors and that it is more pronounced when odors are associated with fatty rather than non-fat foods. It also reveals that an appetence measure is more sensitive than a pleasantness measure for describing an acute reward modulation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Enhancement of Retronasal Odors by Taste

PubMed Central

Nachtigal, Danielle; Hammond, Samuel; Lim, Juyun

2012-01-01

Psychophysical studies of interactions between retronasal olfaction and taste have focused most often on the enhancement of tastes by odors, which has been attributed primarily to a response bias (i.e., halo dumping). Based upon preliminary evidence that retronasal odors could also be enhanced by taste, the present study measured both forms of enhancement using appropriate response categories. In the first experiment, subjects rated taste (“sweet,” “sour,” “salty,” and “bitter”) and odor (“other”) intensity for aqueous samples of 3 tastants (sucrose, NaCl, and citric acid) and 3 odorants (vanillin, citral, and furaneol), both alone and in taste–odor mixtures. The results showed that sucrose, but not the other taste stimuli, significantly increased the perceived intensity of all 3 odors. Enhancement of tastes by odors was inconsistent and generally weaker than enhancement of odors by sucrose. A second experiment used a flavored beverage and a custard dessert to test whether the findings from the first experiment would hold for the perception of actual foods. Adding sucrose significantly enhanced the intensity of “cherry” and “vanilla” flavors, whereas adding vanillin did not significantly enhance the intensity of sweetness. It is proposed that enhancement of retronasal odors by a sweet stimulus results from an adaptive sensory mechanism that serves to increase the salience of the flavor of nutritive foods. PMID:21798851

The impact of expertise in olfaction

PubMed Central

Royet, Jean-Pierre; Plailly, Jane; Saive, Anne-Lise; Veyrac, Alexandra; Delon-Martin, Chantal

2013-01-01

Olfactory expertise remains poorly understood, most likely because experts in odor, such as perfumers, sommeliers, and oenologists, are much rarer than experts in other modalities, such as musicians or sportsmen. In this review, we address the specificities of odor expertise in both odor experts and in a priori untrained individuals who have undergone specific olfactory training in the frame of an experiment, such as repeated exposure to odors or associative learning. Until the 21st century, only the behavioral effects of olfactory training of untrained control individuals had been reported, revealing an improvement of olfactory performance in terms of sensitivity, discrimination, memory, and identification. Behavioral studies of odor experts have been scarce, with inconsistent or inconclusive results. Recently, the development of cerebral imaging techniques has enabled the identification of brain areas and neural networks involved in odor processing, revealing functional and structural modifications as a function of experience. The behavioral approach to odor expertise has also evolved. Researchers have particularly focused on odor mental imagery, which is characteristic of odor experts, because this ability is absent in the average person but is part of a perfumer’s professional practice. This review summarizes behavioral, functional, and structural findings on odor expertise. These data are compared with those obtained using animals subjected to prolonged olfactory exposure or to olfactory-enriched environments and are discussed in the context of functional and structural plasticity. PMID:24379793

Post-eclosion odor experience modifies olfactory receptor neuron coding in Drosophila

PubMed Central

Iyengar, Atulya; Chakraborty, Tuhin Subhra; Goswami, Sarit Pati; Wu, Chun-Fang; Siddiqi, Obaid

2010-01-01

Olfactory responses of Drosophila undergo pronounced changes after eclosion. The flies develop attraction to odors to which they are exposed and aversion to other odors. Behavioral adaptation is correlated with changes in the firing pattern of olfactory receptor neurons (ORNs). In this article, we present an information-theoretic analysis of the firing pattern of ORNs. Flies reared in a synthetic odorless medium were transferred after eclosion to three different media: (i) a synthetic medium relatively devoid of odor cues, (ii) synthetic medium infused with a single odorant, and (iii) complex cornmeal medium rich in odors. Recordings were made from an identified sensillum (type II), and the Jensen–Shannon divergence (DJS) was used to assess quantitatively the differences between ensemble spike responses to different odors. Analysis shows that prolonged exposure to ethyl acetate and several related esters increases sensitivity to these esters but does not improve the ability of the fly to distinguish between them. Flies exposed to cornmeal display varied sensitivity to these odorants and at the same time develop greater capacity to distinguish between odors. Deprivation of odor experience on an odorless synthetic medium leads to a loss of both sensitivity and acuity. Rich olfactory experience thus helps to shape the ORNs response and enhances its discriminative power. The experiments presented here demonstrate an experience-dependent adaptation at the level of the receptor neuron. PMID:20448199

Post-eclosion odor experience modifies olfactory receptor neuron coding in Drosophila.

PubMed

Iyengar, Atulya; Chakraborty, Tuhin Subhra; Goswami, Sarit Pati; Wu, Chun-Fang; Siddiqi, Obaid

2010-05-25

Olfactory responses of Drosophila undergo pronounced changes after eclosion. The flies develop attraction to odors to which they are exposed and aversion to other odors. Behavioral adaptation is correlated with changes in the firing pattern of olfactory receptor neurons (ORNs). In this article, we present an information-theoretic analysis of the firing pattern of ORNs. Flies reared in a synthetic odorless medium were transferred after eclosion to three different media: (i) a synthetic medium relatively devoid of odor cues, (ii) synthetic medium infused with a single odorant, and (iii) complex cornmeal medium rich in odors. Recordings were made from an identified sensillum (type II), and the Jensen-Shannon divergence (D(JS)) was used to assess quantitatively the differences between ensemble spike responses to different odors. Analysis shows that prolonged exposure to ethyl acetate and several related esters increases sensitivity to these esters but does not improve the ability of the fly to distinguish between them. Flies exposed to cornmeal display varied sensitivity to these odorants and at the same time develop greater capacity to distinguish between odors. Deprivation of odor experience on an odorless synthetic medium leads to a loss of both sensitivity and acuity. Rich olfactory experience thus helps to shape the ORNs response and enhances its discriminative power. The experiments presented here demonstrate an experience-dependent adaptation at the level of the receptor neuron.

Recognition of the Component Odors in Mixtures

PubMed Central

Fletcher, Dane B; Hettinger, Thomas P

2017-01-01

Abstract Natural olfactory stimuli are volatile-chemical mixtures in which relative perceptual saliencies determine which odor-components are identified. Odor identification also depends on rapid selective adaptation, as shown for 4 odor stimuli in an earlier experimental simulation of natural conditions. Adapt-test pairs of mixtures of water-soluble, distinct odor stimuli with chemical features in common were studied. Identification decreased for adapted components but increased for unadapted mixture-suppressed components, showing compound identities were retained, not degraded to individual molecular features. Four additional odor stimuli, 1 with 2 perceptible odor notes, and an added “water-adapted” control tested whether this finding would generalize to other 4-compound sets. Selective adaptation of mixtures of the compounds (odors): 3 mM benzaldehyde (cherry), 5 mM maltol (caramel), 1 mM guaiacol (smoke), and 4 mM methyl anthranilate (grape-smoke) again reciprocally unmasked odors of mixture-suppressed components in 2-, 3-, and 4-component mixtures with 2 exceptions. The cherry note of “benzaldehyde” (itself) and the shared note of “methyl anthranilate and guaiacol” (together) were more readily identified. The pervasive mixture-component dominance and dynamic perceptual salience may be mediated through peripheral adaptation and central mutual inhibition of neural responses. Originating in individual olfactory receptor variants, it limits odor identification and provides analytic properties for momentary recognition of a few remaining mixture-components. PMID:28641388

Changes in Men's Salivary Testosterone and Cortisol Levels, and in Sexual Desire after Smelling Female Axillary and Vulvar Scents.

PubMed

Cerda-Molina, Ana Lilia; Hernández-López, Leonor; de la O, Claudio E; Chavira-Ramírez, Roberto; Mondragón-Ceballos, Ricardo

2013-01-01

Several studies have shown that a woman's vaginal or axillary odors convey information on her attractivity. Yet, whether such scents induce psychoneuroendocrinological changes in perceivers is still controversial. We studied if smelling axillary and vulvar odors collected in the periovulatory and late luteal phases of young women modify salivary testosterone and cortisol levels, as well as sexual desire in men. Forty-five women and 115 men, all of them college students and unacquainted with each other, participated in the study. Female odors were collected on pads affixed to the axilla and on panty protectors both worn the entire night before experiments. Men provided five saliva samples, a basal one before the smelling procedure, and four more 15, 30, 60, and 75 min after exposure to odors. Immediately after smelling the odor source, men answered a questionnaire rating hedonic qualities of scents, and after providing the last saliva sample they answered questionnaire on sexual desire. We found that periovulatory axillary and vulvar odors increased testosterone and cortisol levels, with vulvar scents producing a more prolonged effect. Luteal axilla odors decreased testosterone and cortisol levels, while luteal vulva odors increased cortisol. Periovulatory axilla and vulva scents accounted for a general increase of interest in sex. These odors were also rated as more pleasant and familiar, while luteal vulvar odors were perceived as intense and unpleasant.

Changes in Men’s Salivary Testosterone and Cortisol Levels, and in Sexual Desire after Smelling Female Axillary and Vulvar Scents

PubMed Central

Cerda-Molina, Ana Lilia; Hernández-López, Leonor; de la O, Claudio E.; Chavira-Ramírez, Roberto; Mondragón-Ceballos, Ricardo

2013-01-01

Several studies have shown that a woman’s vaginal or axillary odors convey information on her attractivity. Yet, whether such scents induce psychoneuroendocrinological changes in perceivers is still controversial. We studied if smelling axillary and vulvar odors collected in the periovulatory and late luteal phases of young women modify salivary testosterone and cortisol levels, as well as sexual desire in men. Forty-five women and 115 men, all of them college students and unacquainted with each other, participated in the study. Female odors were collected on pads affixed to the axilla and on panty protectors both worn the entire night before experiments. Men provided five saliva samples, a basal one before the smelling procedure, and four more 15, 30, 60, and 75 min after exposure to odors. Immediately after smelling the odor source, men answered a questionnaire rating hedonic qualities of scents, and after providing the last saliva sample they answered questionnaire on sexual desire. We found that periovulatory axillary and vulvar odors increased testosterone and cortisol levels, with vulvar scents producing a more prolonged effect. Luteal axilla odors decreased testosterone and cortisol levels, while luteal vulva odors increased cortisol. Periovulatory axilla and vulva scents accounted for a general increase of interest in sex. These odors were also rated as more pleasant and familiar, while luteal vulvar odors were perceived as intense and unpleasant. PMID:24194730

Mice with a "monoclonal nose": perturbations in an olfactory map impair odor discrimination.

PubMed

Fleischmann, Alexander; Shykind, Benjamin M; Sosulski, Dara L; Franks, Kevin M; Glinka, Meredith E; Mei, Dan Feng; Sun, Yonghua; Kirkland, Jennifer; Mendelsohn, Monica; Albers, Mark W; Axel, Richard

2008-12-26

We have altered the neural representation of odors in the brain by generating a mouse with a "monoclonal nose" in which greater than 95% of the sensory neurons express a single odorant receptor, M71. As a consequence, the frequency of sensory neurons expressing endogenous receptor genes is reduced 20-fold. We observe that these mice can smell, but odor discrimination and performance in associative olfactory learning tasks are impaired. However, these mice cannot detect the M71 ligand acetophenone despite the observation that virtually all sensory neurons and glomeruli are activated by this odor. The M71 transgenic mice readily detect other odors in the presence of acetophenone. These observations have implications for how receptor activation in the periphery is represented in the brain and how these representations encode odors.

Blue petrels recognize the odor of their egg.

PubMed

Leclaire, Sarah; Bourret, Vincent; Bonadonna, Francesco

2017-09-01

Most studies on avian olfactory communication have focused on mate choice, and the importance of olfaction in subsequent nesting stages has been poorly explored. In particular, the role of olfactory cues in egg recognition has received little attention, despite eggs potentially being spread with parental odorous secretions known to elicit individual discrimination. Here, we used behavioral choice tests to determine whether female blue petrels ( Halobaena caerulea ) can discriminate the odor of their own egg from the odor of a conspecific egg. Females preferentially approached the odor of their own egg, suggesting that blue petrels can recognize their own egg using odor cues. This finding raises the question of the adaptive value of this mechanism, and may inspire further research on odor-based egg discrimination in species suffering brood parasitism. © 2017. Published by The Company of Biologists Ltd.

Emotion experienced during encoding enhances odor retrieval cue effectiveness.

PubMed

Herz, R S

1997-01-01

Emotional potentiation may be a key variable in the formation of odor-associated memory. Two experiments were conducted in which a distinctive ambient odor was present or absent during encoding and retrieval sessions and subjects were in an anxious or neutral mood during encoding. Subjects' mood at retrieval was not manipulated. The laboratory mood induction used in Experiment 1 suggested that anxiety might increase the effectiveness of an odor retrieval cue. This trend was confirmed in Experiment 2 by capturing a naturally stressful situation. Subjects who had an ambient odor cue available and were in a preexam state during encoding recalled more words than subjects in any other group. These data are evidence that heightened emotion experienced during encoding with an ambient odor can enhance the effectiveness of an odor as a cue to memory.

Body odors promote automatic imitation in autism.

PubMed

Parma, Valentina; Bulgheroni, Maria; Tirindelli, Roberto; Castiello, Umberto

2013-08-01

Autism spectrum disorders comprise a range of neurodevelopmental pathologies characterized, among other symptoms, by impaired social interactions. Individuals with this diagnosis are reported to often identify people by repetitively sniffing pieces of clothing or the body odor of family members. Since body odors are known to initiate and mediate many different social behaviors, smelling the body odor of a family member might constitute a sensory-based action promoting social contact. In light of this, we hypothesized that the body odor of a family member would facilitate the appearance of automatic imitation, an essential social skill known to be impaired in autism. We recruited 20 autistic and 20 typically developing children. Body odors were collected from the children's mothers' axillae. A child observed a model (their mother or a stranger mother) execute (or not) a reach-to-grasp action toward an object. Subsequently, she performed the same action. The object was imbued with the child's mother's odor, a stranger mother's odor, or no odor. The actions were videotaped, and movement time was calculated post hoc via a digitalization technique. Automatic imitation effects-expressed in terms of total movement time reduction-appear in autistic children only when exposed to objects paired with their own mother's odor. The maternal odor, which conveys a social message otherwise neglected, helps autistic children to covertly imitate the actions of others. Our results represent a starting point holding theoretical and practical relevance for the development of new strategies to enhance communication and social behavior among autistic individuals. Copyright © 2013 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

The Odor Context Facilitates the Perception of Low-Intensity Facial Expressions of Emotion

PubMed Central

Leleu, Arnaud; Demily, Caroline; Franck, Nicolas; Durand, Karine; Schaal, Benoist; Baudouin, Jean-Yves

2015-01-01

It has been established that the recognition of facial expressions integrates contextual information. In this study, we aimed to clarify the influence of contextual odors. The participants were asked to match a target face varying in expression intensity with non-ambiguous expressive faces. Intensity variations in the target faces were designed by morphing expressive faces with neutral faces. In addition, the influence of verbal information was assessed by providing half the participants with the emotion names. Odor cues were manipulated by placing participants in a pleasant (strawberry), aversive (butyric acid), or no-odor control context. The results showed two main effects of the odor context. First, the minimum amount of visual information required to perceive an expression was lowered when the odor context was emotionally congruent: happiness was correctly perceived at lower intensities in the faces displayed in the pleasant odor context, and the same phenomenon occurred for disgust and anger in the aversive odor context. Second, the odor context influenced the false perception of expressions that were not used in target faces, with distinct patterns according to the presence of emotion names. When emotion names were provided, the aversive odor context decreased intrusions for disgust ambiguous faces but increased them for anger. When the emotion names were not provided, this effect did not occur and the pleasant odor context elicited an overall increase in intrusions for negative expressions. We conclude that olfaction plays a role in the way facial expressions are perceived in interaction with other contextual influences such as verbal information. PMID:26390036

DESIGN MANUAL: ODOR AND CORROSION CONTROL IN SANITARY SEWERAGE SYSTEMS AND TREATMENT PLANTS

EPA Science Inventory

Wastewater is known to the public for its potential to create odor nuisance. Sometimes it is the odors escaping from sewer manholes that cause complaints; more commonly, the odor source is a wastewater treatment facility. Yet there are wastewater treatment facilities that are fr...

Recovery of agricultural odors and odorous compounds from polyvinyl fluoride film bags

USDA-ARS?s Scientific Manuscript database

Accurate sampling methods are necessary when quantifying odor and volatile organic compound emissions at agricultural facilities. The commonly accepted methodology in the U.S. has been to collect odor samples in polyvinyl fluoride bags (PVF, brand name Tedlar®) and, subsequently, analyze with human ...

The Enantioselectivity of Odor Sensation: Some Examples for Undergraduate Chemistry Courses

ERIC Educational Resources Information Center

Kraft, Philip; Mannschreck, Albrecht

2010-01-01

This article discusses seven chiral odorants that demonstrate the enantioselectivity of odor sensation: carvone, Celery Ketone, camphor, Florhydral, 3-methyl-3-sulfanylhexan-1-ol, muscone, and methyl jasmonate. After a general introduction of the odorant-receptor interaction and the combinatorial code of olfaction, the olfactory properties of the…

Advances in artificial olfaction: sensors and applications.

PubMed

Gutiérrez, J; Horrillo, M C

2014-06-01

The artificial olfaction, based on electronic systems (electronic noses), includes three basic functions that operate on an odorant: a sample handler, an array of gas sensors, and a signal-processing method. The response of these artificial systems can be the identity of the odorant, an estimate concentration of the odorant, or characteristic properties of the odour as might be perceived by a human. These electronic noses are bio inspired instruments that mimic the sense of smell. The complexity of most odorants makes characterisation difficult with conventional analysis techniques, such as gas chromatography. Sensory analysis by a panel of experts is a costly process since it requires trained people who can work for only relatively short periods of time. The electronic noses are easy to build, provide short analysis times, in real time and on-line, and show high sensitivity and selectivity to the tested odorants. These systems are non-destructive techniques used to characterise odorants in diverse applications linked with the quality of life such as: control of foods, environmental quality, citizen security or clinical diagnostics. However, there is much research still to be done especially with regard to new materials and sensors technology, data processing, interpretation and validation of results. This work examines the main features of modern electronic noses and their most important applications in the environmental, and security fields. The above mentioned main components of an electronic nose (sample handling system, more advanced materials and methods for sensing, and data processing system) are described. Finally, some interesting remarks concerning the strengths and weaknesses of electronic noses in the different applications are also mentioned. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecular Basis of N,N-Diethyl-3-Methylbenzamide (DEET) in Repelling the Common Bed Bug, Cimex lectularius.

PubMed

Liu, Feng; Xia, Xiaoming; Liu, Nannan

2017-01-01

As the most extensively used chemical repellent, N,N-diethyl-3-methylbenzamide (DEET) displayed repellency to a wide range of insects, including the common bed bug, Cimex lectularius . While the neuronal or molecular basis involved in DEET's repellency have been majorly focused on mosquitos and fruit flies, DEET's repellency to the common bed bug is largely unreached. To gain new insights into the cellular and molecular mechanisms in DEET's repellency to the common bed bug, we characterized the neuronal response of bed bugs to DEET, identified the olfactory receptors targeted by DEET and demonstrated the interfering effect of DEET on bed bug's responses to human odorants. High doses of DEET were required for activating the olfactory receptor neurons in the sensilla of bed bugs and at least three DEET-sensitive receptors were functionally deciphered. These DEET-sensitive receptors presented even more sensitive to certain botanical terpenes/terpenoids which also displayed repellency at varying levels for bed bugs. In addition, DEET produced a blocking effect on the neuronal responses of bed bugs to specific human odors and showed inhibitory effect on the function of odorant receptors in responding to certain human odors. Taken together, our results indicate that DEET may function as a stimulus that triggers avoidance behaviors and a molecular "confusant" for interrupting the host odor recognition in the odorant receptors of bed bugs. The receptors that coincidently responded to both synthetic DEET and botanical terpenes/terpenoids suggested that DEET probably target on receptors that originally responded to terpenes/terpenoids. This study gave novel insight into the mechanisms of DEET's repellency to bed bugs and also provided valuable information for developing new reagents for bed bug control.

Blunted Hypothalamo-pituitary Adrenal Axis Response to Predator Odor Predicts High Stress Reactivity

PubMed Central

Whitaker, Annie M.; Gilpin, Nicholas W.

2015-01-01

Individuals with trauma- and stress-related disorders exhibit increases in avoidance of trauma-related stimuli, heightened anxiety and altered neuroendocrine stress responses. Our laboratory uses a rodent model of stress that mimics the avoidance symptom cluster associated with stress-related disorders. Animals are classified as ‘Avoiders’ or Non-Avoiders' post-stress based on avoidance of predator-odor paired context. Utilizing this model, we are able to examine subpopulation differences in stress reactivity. Here, we used this predator odor model of stress to examine differences in anxiety-like behavior and hypothalamo-pituitary adrenal (HPA) axis function in animals that avoid a predator-paired context relative to those that do not. Rats were exposed to predator odor stress paired with a context and tested for avoidance (24 hours and 11 days), anxiety-like behavior (48 hours and 5 days) and HPA activation following stress. Control animals were exposed to room air. Predator odor stress produced avoidance in approximately 65% of the animals at 24 hours that persisted 11 days post-stress. Both Avoiders and Non-Avoiders exhibited heightened anxiety-like behavior at 48 hours and 5 days post-stress when compared to unstressed Controls. Non-Avoiders exhibited significant increases in circulating adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations immediately following predator odor stress compared to Controls and this response was significantly attenuated in Avoiders. There was an inverse correlation between circulating ACTH/CORT concentrations and avoidance, indicating that lower levels of ACTH/CORT predicted higher levels of avoidance. These results suggest that stress effects on HPA stress axis activation predict long-term avoidance of stress-paired stimuli, and builds on previous data showing the utility of this model for exploring the neurobiological mechanisms of trauma- and stress-related disorders. PMID:25824191

Molecular Basis of N,N-Diethyl-3-Methylbenzamide (DEET) in Repelling the Common Bed Bug, Cimex lectularius

PubMed Central

Liu, Feng; Xia, Xiaoming; Liu, Nannan

2017-01-01

As the most extensively used chemical repellent, N,N-diethyl-3-methylbenzamide (DEET) displayed repellency to a wide range of insects, including the common bed bug, Cimex lectularius. While the neuronal or molecular basis involved in DEET's repellency have been majorly focused on mosquitos and fruit flies, DEET's repellency to the common bed bug is largely unreached. To gain new insights into the cellular and molecular mechanisms in DEET's repellency to the common bed bug, we characterized the neuronal response of bed bugs to DEET, identified the olfactory receptors targeted by DEET and demonstrated the interfering effect of DEET on bed bug's responses to human odorants. High doses of DEET were required for activating the olfactory receptor neurons in the sensilla of bed bugs and at least three DEET-sensitive receptors were functionally deciphered. These DEET-sensitive receptors presented even more sensitive to certain botanical terpenes/terpenoids which also displayed repellency at varying levels for bed bugs. In addition, DEET produced a blocking effect on the neuronal responses of bed bugs to specific human odors and showed inhibitory effect on the function of odorant receptors in responding to certain human odors. Taken together, our results indicate that DEET may function as a stimulus that triggers avoidance behaviors and a molecular “confusant” for interrupting the host odor recognition in the odorant receptors of bed bugs. The receptors that coincidently responded to both synthetic DEET and botanical terpenes/terpenoids suggested that DEET probably target on receptors that originally responded to terpenes/terpenoids. This study gave novel insight into the mechanisms of DEET's repellency to bed bugs and also provided valuable information for developing new reagents for bed bug control. PMID:28676765

Identification of Odor-Processing Genes in the Emerald Ash Borer, Agrilus planipennis

PubMed Central

Mamidala, Praveen; Wijeratne, Asela J.; Wijeratne, Saranga; Poland, Therese; Qazi, Sohail S.; Doucet, Daniel; Cusson, Michel; Beliveau, Catherine; Mittapalli, Omprakash

2013-01-01

Background Insects rely on olfaction to locate food, mates, and suitable oviposition sites for successful completion of their life cycle. Agrilus planipennis Fairmaire (emerald ash borer) is a serious invasive insect pest that has killed tens of millions of North American ash (Fraxinus spp) trees and threatens the very existence of the genus Fraxinus. Adult A. planipennis are attracted to host volatiles and conspecifics; however, to date no molecular knowledge exists on olfaction in A. planipennis. Hence, we undertook an antennae-specific transcriptomic study to identify the repertoire of odor processing genes involved in A. planipennis olfaction. Methodology and Principal Findings We acquired 139,085 Roche/454 GS FLX transcriptomic reads that were assembled into 30,615 high quality expressed sequence tags (ESTs), including 3,249 isotigs and 27,366 non-isotigs (contigs and singletons). Intriguingly, the majority of the A. planipennis antennal transcripts (59.72%) did not show similarity with sequences deposited in the non-redundant database of GenBank, potentially representing novel genes. Functional annotation and KEGG analysis revealed pathways associated with signaling and detoxification. Several odor processing genes (9 odorant binding proteins, 2 odorant receptors, 1 sensory neuron membrane protein and 134 odorant/xenobiotic degradation enzymes, including cytochrome P450s, glutathione-S-transferases; esterases, etc.) putatively involved in olfaction processes were identified. Quantitative PCR of candidate genes in male and female A. planipennis in different developmental stages revealed developmental- and sex-biased expression patterns. Conclusions and Significance The antennal ESTs derived from A. planipennis constitute a rich molecular resource for the identification of genes potentially involved in the olfaction process of A. planipennis. These findings should help in understanding the processing of antennally-active compounds (e.g. 7-epi-sesquithujene) previously identified in this serious invasive pest. PMID:23424668

Characterization of the Key Aroma Volatile Compounds in Cranberry (Vaccinium macrocarpon Ait.) Using Gas Chromatography-Olfactometry (GC-O) and Odor Activity Value (OAV).

PubMed

Zhu, JianCai; Chen, Feng; Wang, LingYing; Niu, YunWei; Chen, HeXing; Wang, HongLin; Xiao, ZuoBing

2016-06-22

The volatile compounds of cranberries obtained from four cultivars (Early Black, Y1; Howes, Y2; Searles, Y3; and McFarlin, Y4) were analyzed by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and GC-flame photometric detection (FPD). The result presented that a total of thirty-three, thirty-four, thirty-four, and thirty-six odor-active compounds were identified by GC-O in the Y1, Y2, Y3, and Y4, respectively. In addition, twenty-two, twenty-two, thirty, and twenty-seven quantified compounds were demonstrated as important odorants according to odor activity values (OAVs > 1). Among these compounds, hexanal (OAV: 27-60), pentanal (OAV: 31-51), (E)-2-heptenal (OAV: 17-66), (E)-2-hexenal (OAV: 18-63), (E)-2-octenal (OAV: 10-28), (E)-2-nonenal (OAV: 8-77), ethyl 2-methylbutyrate (OAV: 10-33), β-ionone (OAV: 8-73), 2-methylbutyric acid (OAV: 18-37), and octanal (OAV: 4-24) contributed greatly to the aroma of cranberry. Partial least-squares regression (PLSR) was used to process the mean data accumulated from sensory evaluation by the panelists, odor-active aroma compounds (OAVs > 1), and samples. Sample Y3 was highly correlated with the sensory descriptors "floral" and "fruity". Sample Y4 was greatly related to the sensory descriptors "mellow" and "green and grass". Finally, an aroma reconstitution (Model A) was prepared by mixing the odor-active aroma compounds (OAVs > 1) based on their measured concentrations in the Y1 sample, indicating that the aroma profile of the reconstitution was pretty similar to that of the original sample.

Identification of odor-processing genes in the emerald ash borer, Agrilus planipennis.

PubMed

Mamidala, Praveen; Wijeratne, Asela J; Wijeratne, Saranga; Poland, Therese; Qazi, Sohail S; Doucet, Daniel; Cusson, Michel; Beliveau, Catherine; Mittapalli, Omprakash

2013-01-01

Insects rely on olfaction to locate food, mates, and suitable oviposition sites for successful completion of their life cycle. Agrilus planipennis Fairmaire (emerald ash borer) is a serious invasive insect pest that has killed tens of millions of North American ash (Fraxinus spp) trees and threatens the very existence of the genus Fraxinus. Adult A. planipennis are attracted to host volatiles and conspecifics; however, to date no molecular knowledge exists on olfaction in A. planipennis. Hence, we undertook an antennae-specific transcriptomic study to identify the repertoire of odor processing genes involved in A. planipennis olfaction. We acquired 139,085 Roche/454 GS FLX transcriptomic reads that were assembled into 30,615 high quality expressed sequence tags (ESTs), including 3,249 isotigs and 27,366 non-isotigs (contigs and singletons). Intriguingly, the majority of the A. planipennis antennal transcripts (59.72%) did not show similarity with sequences deposited in the non-redundant database of GenBank, potentially representing novel genes. Functional annotation and KEGG analysis revealed pathways associated with signaling and detoxification. Several odor processing genes (9 odorant binding proteins, 2 odorant receptors, 1 sensory neuron membrane protein and 134 odorant/xenobiotic degradation enzymes, including cytochrome P450s, glutathione-S-transferases; esterases, etc.) putatively involved in olfaction processes were identified. Quantitative PCR of candidate genes in male and female A. planipennis in different developmental stages revealed developmental- and sex-biased expression patterns. The antennal ESTs derived from A. planipennis constitute a rich molecular resource for the identification of genes potentially involved in the olfaction process of A. planipennis. These findings should help in understanding the processing of antennally-active compounds (e.g. 7-epi-sesquithujene) previously identified in this serious invasive pest.

Blunted hypothalamo-pituitary adrenal axis response to predator odor predicts high stress reactivity.

PubMed

Whitaker, Annie M; Gilpin, Nicholas W

2015-08-01

Individuals with trauma- and stress-related disorders exhibit increases in avoidance of trauma-related stimuli, heightened anxiety and altered neuroendocrine stress responses. Our laboratory uses a rodent model of stress that mimics the avoidance symptom cluster associated with stress-related disorders. Animals are classified as 'Avoiders' or 'Non-Avoiders' post-stress based on avoidance of predator-odor paired context. Utilizing this model, we are able to examine subpopulation differences in stress reactivity. Here, we used this predator odor model of stress to examine differences in anxiety-like behavior and hypothalamo-pituitary adrenal (HPA) axis function in animals that avoid a predator-paired context relative to those that do not. Rats were exposed to predator odor stress paired with a context and tested for avoidance (24h and 11days), anxiety-like behavior (48h and 5days) and HPA activation following stress. Control animals were exposed to room air. Predator odor stress produced avoidance in approximately 65% of the animals at 24h that persisted 11days post-stress. Both Avoiders and Non-Avoiders exhibited a heightened anxiety-like behavior at 48h and 5days post-stress when compared to unstressed Controls. Non-Avoiders exhibited significant increases in circulating adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations immediately following predator odor stress compared to Controls and this response was significantly attenuated in Avoiders. There was an inverse correlation between circulating ACTH/CORT concentrations and avoidance, indicating that lower levels of ACTH/CORT predicted higher levels of avoidance. These results suggest that stress effects on HPA stress axis activation predict long-term avoidance of stress-paired stimuli, and build on previous data showing the utility of this model for exploring the neurobiological mechanisms of trauma- and stress-related disorders. Copyright © 2015. Published by Elsevier Inc.

Freezing to the predator odor 2,4,5 dihydro 2,5 trimethylthiazoline (TMT) is disrupted by olfactory bulb removal but not trigeminal deafferentation.

PubMed

Ayers, Luke W; Asok, Arun; Heyward, Frankie D; Rosen, Jeffrey B

2013-09-15

2,4,5 dihydro 2,5 trimethylthiazoline (TMT) is a synthesized component of red fox anal secretions that reliably elicits defensive behaviors in rats and mice. TMT differs from other predator odors because it is a single molecule, it can be synthesized in large quantities, and the dose for exposure is highly controllable in an experimental setting. TMT has become a popular tool for studying the brain mechanisms that mediate innate fear behavior to olfactory stimuli. However, this view of TMT as a biologically relevant olfactory stimulus has been challenged by suggestions that the odor elicits fear behavior due to its irritating properties, presumably working through a nociceptive mechanism. To address this criticism our lab measured freezing behavior in rats during exposures to 2 odors (TMT and butyric acid) and H2O (no odor control) following either surgical transection of the trigeminal nerves or ablation of the olfactory bulbs. Our findings (Experiment 1) indicate that freezing behavior to TMT requires an intact olfactory system, as indicated by the loss of freezing following olfactory bulb removal. Experiment 2 revealed that rats with trigeminal nerve transection freeze normally to TMT, suggesting the olfactory system mediates this behavior to TMT. A replication of Experiment 1 that included contextual fear conditioning revealed that the decreased freezing behavior was not due to an inability of olfactory bulb ablated rats to freeze (Experiment 3). Taken together, these findings support TMT's role as an ecologically relevant predator odor useful in experiments of unconditioned fear that is mediated via olfaction and not nociception. Copyright © 2013 Elsevier B.V. All rights reserved.

The pollution characteristics of odor, volatile organochlorinated compounds and polycyclic aromatic hydrocarbons emitted from plastic waste recycling plants.

PubMed

Tsai, Chung-Jung; Chen, Mei-Lien; Chang, Keng-Fu; Chang, Fu-Kuei; Mao, I-Fang

2009-02-01

Plastic waste treatment trends toward recycling in many countries; however, the melting process in the facilities which adopt material recycling method for treating plastic waste may emit toxicants and cause sensory annoyance. The objectives of this study were to analyze the pollution characteristics of the emissions from the plastic waste recycling plants, particularly in harmful volatile organochlorinated compounds, polycyclic aromatic hydrocarbons (PAHs), odor levels and critical odorants. Ten large recycling plants were selected for analysis of odor concentration (OC), volatile organic compounds (VOCs) and PAHs inside and outside the plants using olfactometry, gas chromatography-mass spectrometry and high performance liquid chromatography-fluorescence detector, respectively. The olfactometric results showed that the melting processes used for treating polyethylene/polypropylene (PE/PP) and polyvinyl chloride (PVC) plastic waste significantly produced malodor, and the odor levels at downwind boundaries were 100-229 OC, which all exceeded Taiwan's EPA standard of 50 OC. Toluene, ethylbenzene, 4-methyl-2-pentanone, methyl methacrylate and acrolein accounted for most odors compared to numerous VOCs. Sixteen organochlorinated compounds were measured in the ambient air emitted from the PVC plastic waste recycling plant and total concentrations were 245-553 microg m(-3); most were vinyl chloride, chloroform and trichloroethylene. Concentrations of PAHs inside the PE/PP plant were 8.97-252.16 ng m(-3), in which the maximum level were 20-fold higher than the levels detected from boundaries. Most of these recycling plants simply used filter to treat the melting fumes, and this could not efficiently eliminate the gaseous compounds and malodor. Improved exhaust air pollution control were strongly recommended in these industries.

Circuit oscillations in odor perception and memory.

PubMed

Kay, Leslie M

2014-01-01

Olfactory system neural oscillations as seen in the local field potential have been studied for many decades. Recent research has shown that there is a functional role for the most studied gamma oscillations (40-100Hz in rats and mice, and 20Hz in insects), without which fine odor discrimination is poor. When these oscillations are increased artificially, fine discrimination is increased, and when rats learn difficult and highly overlapping odor discriminations, gamma is increased in power. Because of the depth of study on this oscillation, it is possible to point to specific changes in neural firing patterns as represented by the increase in gamma oscillation amplitude. However, we know far less about the mechanisms governing beta oscillations (15-30Hz in rats and mice), which are best associated with associative learning of responses to odor stimuli. These oscillations engage every part of the olfactory system that has so far been tested, plus the hippocampus, and the beta oscillation frequency band is the one that is most reliably coherent with other regions during odor processing. Respiratory oscillations overlapping with the theta frequency band (2-12Hz) are associated with odor sniffing and normal breathing in rats. They also show coupling in some circumstances between olfactory areas and rare coupling between the hippocampus and olfactory bulb. The latter occur in specific learning conditions in which coherence strength is negatively or positively correlated with performance, depending on the task. There is still much to learn about the role of neural oscillations in learning and memory, but techniques that have been brought to bear on gamma oscillations (current source density, computational modeling, slice physiology, behavioral studies) should deliver much needed knowledge of these events. © 2014 Elsevier B.V. All rights reserved.

Principal Factors for High Performance of Odor and Methane degrading Biocover using Network Analysis

NASA Astrophysics Data System (ADS)

Jung, H.; Yun, J.; O, G. C.; Ryu, H. W.; Jeon, J. M.; Cho, K. S.

2016-12-01

Methane is 25 times more powerful greenhouse gas than carbon dioxide and plays an important role in global warming. Landfills are one of the biggest methane sources and have emitted 37% of anthropogenic methane in Korea. Applying biocovers in landfills is known to be efficient for the simultaneous mitigation of methane as well as odor which occurs severe civil claims. In this study, three pilot-scale biocovers (2.5mx5mx1m) were constructed in a sanitary landfill at Gwangyang, Korea to establish the optimal operational conditions of biocover. All biocovers are filled with soil, EG microbial agent, food waste compost, and perlite with different combination. Pilot-scale biocovers have been operated since January in this year for simultaneous removal of odor and methane. The concentrations of methane and odors such as ammonia, H2S, methyl mercaptane, methylsulfide, dimetyl disulfide, i-valeraldehyde, and styrene were measured at the inlet and outlet of biocovers each month using GC and HPLC for removal performance evaluation. The biocover with highest removal efficiency eliminated 98.4% of odor and 100.0% of methane. All removal efficiencies of odor measured during experiment are in 81.1 98.4% range, and those of methane are in 3.6 100.0%. Three months later after biocover construction, all biocovers with mixed packing material showed better methane degradation performance than the biocovers packed only with soil. The packing materials of biocovers were sampled during winter (January), spring (April) and summer (July), and their microbial communities were examined based on 16S rDNA using 454 pyrosequencing to detect microbial factors that affects the removal efficiency. Methanotrophs which are known as methane-degradable bacteria take 10 25% of microbial community in biocovers, and most of those found in biocovers are type methanothrophs. Network analysis is performed and principal factors for performance improvement of biocovers are derived. Based on this study, well-designed biocovers will be newly set up in the operational landfill with the consideration of derived principal factors for high efficiency. This research was supported by the Korea Ministry of Environment as a "Converging Technology Project (2015001640003)".

In vivo bioelectronic nose using transgenic mice for specific odor detection.

PubMed

Gao, Keqiang; Li, Songmin; Zhuang, Liujing; Qin, Zhen; Zhang, Bin; Huang, Liquan; Wang, Ping

2018-04-15

The olfactory system is a natural biosensor since its peripheral olfactory sensory neurons (OSNs) respond to the external stimuli and transmit the signals to the olfactory bulb (OB) where they are integrated and processed. The axonal connections from the OSNs expressing about 1000 different types of odorant receptors are precisely organized and sorted out onto 1800 glomeruli in the OB, from which the olfactory information is delivered to and perceived by the central nervous system. This process is carried out with particularly high sensitivity, specificity and rapidity, which can be used for explosive detection. Biomimetic olfactory biosensors use various biological components from the olfactory system as sensing elements, possessing great commercial prospects. In this study, we utilized the genetically labeled murine M72 olfactory sensory neurons with the green fluorescent protein (GFP) as sensing components and obtained long-term in vivo electrophysiological recordings from the M72 OSNs by implanting the microelectrode arrays (MEAs) into the behaving mouse's OB. The electrophysiological responses showed high reliability, reproducibility and specificity for odor detection, and particularly, the high sensitivity for the detection of odorants that contain benzene rings. Furthermore, our results indicated that it can detect trinitrotoluene (TNT) in liquid at a concentration as low as 10 -5 M and can distinguish TNT from other chemicals with a similar structure. Thus our study demonstrated that the in vivo biomimetic olfactory system could provide novel approaches to enhancing the specificity and increasing working lifespan of olfactory biosensors capable of detecting explosives. Copyright © 2017 Elsevier B.V. All rights reserved.

Preference for human body odors is influenced by gender and sexual orientation.

PubMed

Martins, Yolanda; Preti, George; Crabtree, Christina R; Runyan, Tamar; Vainius, Aldona A; Wysocki, Charles J

2005-09-01

Human body odor may contribute to selection of partners. If so, sexual orientation may influence preference for and perhaps production of human body odors. In a test of these hypotheses, heterosexual and homosexual males and females made two-alternative forced-choice preference judgments for body odors obtained from other heterosexual and homosexual males and females. Subjects chose between odors from (a) heterosexual males and gay males, (b) heterosexual males and heterosexual females, (c) heterosexual females and lesbians, and (d) gay males and lesbians. Results indicate that differences in body odor are detected and responded to on the basis of, in part, an individual's gender and sexual orientation. Possible mechanisms underlying these findings are discussed.

Improved low-cost, MR-compatible olfactometer to deliver tobacco smoke odor

PubMed Central

Lowen, Steven B.; Farmer, Stacey L.; Lukas, Scott E.

2016-01-01

We describe a low-cost, MRI-compatible olfactometer that delivers fresh cigarette smoke odor, a challenging odorant to present, as well as other odorants. This new olfactometer retains all of the advantages of an earlier design that was capable of only delivering volatile odors (Lowen & Lukas, 2006). The new system incorporates a novel switching mechanism that allows it to deliver fresh smoke generated from a burning cigarette during a stimulus presentation paradigm that might be employed in a cue-reactivity experiment. An evaluation study established that the olfactometer reliably delivered smoke to the participants and that tobacco smoke was discriminated from other odorants; there were no adverse reactions to the device. PMID:26896241

Study of odor recorder using Mass Spectrometry

NASA Astrophysics Data System (ADS)

Miura, Tomohiro; Nakamoto, Takamichi; Moriizumi, Toyosaka

It is necessary to determine the recipe of a target odor with sufficient accuracy to realize an odor recorder for recording and reproducing it. We studied the recipe measurement method of a target odor using a mass spectrometry. It was confirmed that the linear superposition was valid when the binary mixture of the apple-flavor components such as isobutyric acid and ethyl valerate was measured. The superposition of a mass spectrum pattern may enable the recipe determination of a multi-component odor easily. In this research, we succeeded in the recipe determinations of orange flavor made up of 14 component odors when its typical recipe, the equalized, the citral-enhanced and the citronellol-enhanced ones were measured.

The Chilean Recluse Spider (Araneae: Sicariidae) Displays Behavioral Responses to Conspecific Odors, but Not to Several General Odorants.

PubMed

Calbiague, Victor Manuel; Olivares, Jesus; Olivares, Erick; Schmachtenberg, Oliver

2017-09-01

Spiders of the family Sicariidae pose a serious threat to affected populations, and Loxosceles laeta (Nicolet) is considered the most venomous species. Development of nontoxic olfaction-based spider repellents or traps is hindered by a current lack of knowledge regarding olfactory system function in arachnids. In the present study, general plant odorants and conspecific odors were tested for behavioral responses in L. laeta. Although general odorants triggered neither attraction nor aversion, conspecific odor of the opposite sex caused aversion in females, and attraction in males. These results support the presence of a specific olfactory system for the detection of conspecifics in L. laeta, but suggest the absence of a broadly tuned system for general odorant detection in this species. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Corticosterone rapidly reduces male odor preferences in female mice.

PubMed

Kavaliers, M; Ossenkopp, K P

2001-09-17

There is accumulating evidence for rapid, non-genomic behavioral effects of various steroids including that of the glucocorticoid, corticosterone. Using an odor preference test, the responses of which are indicative of mate preferences and sexual interest, we examined the effects of acute corticosterone on the responses of oestrous female mice to male odors. Control female mice displayed an overwhelming preference for the odors of male mice. Peripheral administration of corticosterone elicited a significant dose-related (1.0-5.0 mg/kg) decrease in female preference for male odors at 10 min, but not at 60 min, after administration. These inhibitory effects of corticosterone on odor preferences were significantly reduced by the competitive NMDA antagonist, NPC 12626, and enhanced by the GABA antagonist bicuculline. This indicates that corticosterone has rapid inhibitory effects on olfactory mediated female mate preferences and responses to male odor that in part involve interactions with NMDA and GABA receptor mechanisms.

Receptor arrays optimized for natural odor statistics.

PubMed

Zwicker, David; Murugan, Arvind; Brenner, Michael P

2016-05-17

Natural odors typically consist of many molecules at different concentrations. It is unclear how the numerous odorant molecules and their possible mixtures are discriminated by relatively few olfactory receptors. Using an information theoretic model, we show that a receptor array is optimal for this task if it achieves two possibly conflicting goals: (i) Each receptor should respond to half of all odors and (ii) the response of different receptors should be uncorrelated when averaged over odors presented with natural statistics. We use these design principles to predict statistics of the affinities between receptors and odorant molecules for a broad class of odor statistics. We also show that optimal receptor arrays can be tuned to either resolve concentrations well or distinguish mixtures reliably. Finally, we use our results to predict properties of experimentally measured receptor arrays. Our work can thus be used to better understand natural olfaction, and it also suggests ways to improve artificial sensor arrays.

Identification and Quantitation of Potent Odorants in Spearmint Oils.

PubMed

Kelley, Lauren E; Cadwallader, Keith R

2018-03-14

Potent odorants in Native spearmint, Scotch spearmint, and Macho mint oils were determined by the combined use of gas chromatography-olfactometry (GCO), gas chromatography-mass spectrometry (GC-MS), and aroma extract dilution analysis (AEDA). Of the 85 odorants detected, ( R)-(-)-carvone was the most potent odorant in all three spearmint oils. Additional predominant odorants in all spearmint oils included eugenol, ethyl ( S)-(+)-2-methylbutanoate, ( E)-β-damascenone, and (3 E,5 Z)-1,3,5-undecatriene. Forty-six compounds were quantitated using various methods, including 19 by gas chromatography with flame ionization detection (GC-FID), 20 by stable isotope dilution analysis (SIDA), and 14 by GCO dilution analysis. Concentrations were used to calculate the odor activity values (OAVs) for predominant odorants in the oils. Among the compounds quantitated, those with the highest OAVs were ( R)-(-)-carvone, 1,8-cineole, ( E, Z)-2,6-nonadienal, ( E)-β-damascenone, and (3 E,5 Z)-1,3,5-undecatriene.

9 CFR 311.37 - Odors, foreign and urine.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Odors, foreign and urine. 311.37..., foreign and urine. (a) Carcasses which give off a pronounced odor of medicinal, chemical, or other foreign substance shall be condemned. (b) Carcasses which give off a pronounced urine odor shall be condemned. (c...

9 CFR 311.37 - Odors, foreign and urine.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Odors, foreign and urine. 311.37..., foreign and urine. (a) Carcasses which give off a pronounced odor of medicinal, chemical, or other foreign substance shall be condemned. (b) Carcasses which give off a pronounced urine odor shall be condemned. (c...

9 CFR 311.37 - Odors, foreign and urine.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Odors, foreign and urine. 311.37..., foreign and urine. (a) Carcasses which give off a pronounced odor of medicinal, chemical, or other foreign substance shall be condemned. (b) Carcasses which give off a pronounced urine odor shall be condemned. (c...

9 CFR 311.37 - Odors, foreign and urine.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Odors, foreign and urine. 311.37..., foreign and urine. (a) Carcasses which give off a pronounced odor of medicinal, chemical, or other foreign substance shall be condemned. (b) Carcasses which give off a pronounced urine odor shall be condemned. (c...

Episodic Memory: Manipulation and Replay of Episodic Memories by Rats.

PubMed

Wright, Anthony A

2018-06-04

Rats exposed to variable-length, unique-odor lists were tested in distinctive contexts for odors second or forth from list-end. Accurate ability to recall odors backwards from the end of lists points to their ability to manipulate and replay odor-list episodic memories. Copyright © 2018 Elsevier Ltd. All rights reserved.

Women's hedonic ratings of body odor of heterosexual and homosexual men.

PubMed

Sergeant, Mark J T; Dickins, Thomas E; Davies, Mark N O; Griffiths, Mark D

2007-06-01

Men's body odor influences women's mate choice and individual variation among traits affects hedonic perceptions of this odor (e.g., immune system characteristics). Previous research by Sergeant (2002) indicated that one such characteristic is sexual orientation: body odor from homosexual men was perceived by heterosexual women as more hedonically pleasing than that of heterosexual men. The current study re-examined the influence of men's sexual orientation on women's perceptions of body odor. Homosexual (n=10) and heterosexual (n=9) men produced samples of body odor using T-shirts under equivalent environmental conditions. Heterosexual women (n=35) rated these samples, and a set of unused T-shirts, using a series of hedonic scales. Women rated the body odor of homosexual men as being comparatively more pleasant, sexier, and more preferable than that of heterosexual men but not significantly different from the unused T-shirts. This finding was consistent with contemporary research demonstrating that an individual's sexual orientation significantly impacts their olfactory function, both in terms of body odor production and olfactory perceptions of certain compounds.

TRANSITIVITY OF ODOR PREFERENCES: CONSTANT AND PARTICULARITIES IN HEDONIC PERCEPTION

PubMed Central

Brand, Gérard; Haaz, Virginie; Jacquot, Laurence

2012-01-01

Transitivity of preferences has been investigated for a long time in decision-making. In the field of perception, the pleasantness of odors raises several questions related to individual versus cultural or universal preferences and the existence of a classification in a delimited hedonic space. The aim of this study was to test transitivity in olfactory hedonicity using a first panel of 10 mixed odors and a second panel of 10 odors from a delimited floral category. Data were collected by paired comparisons in a two-alternative forced choice. Results in both panels showed a strong transitivity for each participant leading to a linear range of 10 odors classified by preference. However, ranges varied from one participant to another and the mean preferences of the group did not allow one to infer individual's hedonic classification of odors. Moreover, the individual classification appeared stable over time and undisturbed by odorant distractors. These findings suggest that humans have considerable ability to classify odors hedonically as a model of individual preferences in a sensory space usually considered to be more involved in affective/emotional states than in cognitive performances. PMID:23008522

Regulatory Features for Odorant Receptor Genes in the Mouse Genome.

PubMed

Degl'Innocenti, Andrea; D'Errico, Anna

2017-01-01

The odorant receptor genes, seven transmembrane receptor genes constituting the vastest mammalian gene multifamily, are expressed monogenically and monoallelicaly in each sensory neuron in the olfactory epithelium. This characteristic, often referred to as the one neuron-one receptor rule, is driven by mostly uncharacterized molecular dynamics, generally named odorant receptor gene choice . Much attention has been paid by the scientific community to the identification of sequences regulating the expression of odorant receptor genes within their loci , where related genes are usually arranged in genomic clusters. A number of studies identified transcription factor binding sites on odorant receptor promoter sequences. Similar binding sites were also found on a number of enhancers that regulate in cis their transcription, but have been proposed to form interchromosomal networks. Odorant receptor gene choice seems to occur via the local removal of strongly repressive epigenetic markings, put in place during the maturation of the sensory neuron on each odorant receptor locus . Here we review the fast-changing state of art for the study of regulatory features for odorant receptor genes.

Spoilage bacteria of fresh broiler chicken carcasses.

PubMed

Russell, S M; Fletcher, D L; Cox, N A

1995-12-01

Studies were conducted to identify the bacteria responsible for spoilage of fresh broiler chicken carcasses and to characterize the off-odors these bacteria produce. Broiler carcasses were collected from processing plants in the northeast Georgia area, the southeastern U.S., Arkansas, California, and North Carolina. The carcasses were allowed to spoil under controlled conditions at 3 C and spoilage bacteria were isolated. Each spoilage bacterium was separately inoculated into a sterile chicken skin medium, incubated at 25 C for 48 h, and subjectively evaluated for odor. The bacteria isolated from spoiled carcasses that consistently produced off-odors in the chicken skin medium, regardless of the geographical location from which the chickens were obtained, were Shewanella putrefaciens A, B, and D, Pseudomonas fluorescens A, B, and D, and Pseudomonas fragi. These bacteria produced off-odors that resembled "sulfur", "dishrag", "ammonia", "wet dog", "skunk", "dirty socks", "rancid fish", "unspecified bad odor", or a sweet smell resembling "canned corn". Odors produced by the spoilage bacteria were varied; however, odors most associated with spoiled poultry, such as "dishraggy" odors, were produced by the bacteria that were most consistently isolated, such as S. putrefaciens and the pseudomonads.

Effects of diversity in olfactory environment on children's sense of smell.

PubMed

Martinec Nováková, Lenka; Fialová, Jitka; Havlíček, Jan

2018-02-13

Diversity in children's everyday olfactory environment may affect the development of their olfactory abilities and odor awareness. To test this, we collected data on olfactory abilities using the Sniffin' Sticks and odor awareness with Children's Olfactory Behaviors in Everyday Life Questionnaire in 153 preschool children and retested them one and a half year later. Parents completed an inventory on children's exposure to a variety of odors and on their own odor awareness using the Odor Awareness Scale. We controlled for the effects of age and verbal fluency on the children's performance. We found that the children's odor identification and discrimination scores differed as a function of parental odor awareness. Although these effects were rather small, they were commensurate in size with those of gender and age. To the best of our knowledge, this study is the first to present evidence that diversity in children's olfactory environment affects variation in their olfactory abilities and odor awareness. We suggest that future studies consider the long-term impact of perceptual learning out of the laboratory and its consequences for olfactory development.

Odor Memory and Discrimination Covary as a Function of Delay between Encoding and Recall in Rats.

PubMed

Hackett, Chelsea; Choi, Christina; O'Brien, Brenna; Shin, Philip; Linster, Christiane

2015-06-01

Nonassociative odor learning paradigms are often used to assess memory, social recognition and neuromodulation of olfactory pathways. We here use a modified object recognition paradigm to investigate how an important task parameter, delay between encoding and recall trials, affects the properties of this memory. We show that both memory for a previously investigated odorant and discrimination of a novel odorant decay with delay time and that rats can remember an odorant for up to 45min after a single trial encoding event. The number of odorants that can be encoded, as well as the specificity of the encoded memory, decrease with increased delay and also depend on stimulus concentration. Memory for an odorant and discrimination of a novel odorant decay at approximately the same rate, whereas the specificity of the formed memory decays faster than the memory itself. These results have important implications for the interpretation of behavioral data obtained with this paradigm. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Odor Emotional Quality Predicts Odor Identification.

PubMed

Bestgen, Anne-Kathrin; Schulze, Patrick; Kuchinke, Lars

2015-09-01

It is commonly agreed upon a strong link between emotion and olfaction. Odor-evoked memories are experienced as more emotional compared with verbal, visual, and tactile stimuli. Moreover, the emotional quality of odor cues increases memory performance, but contrary to this, odors are poor retrieval cues for verbal labels. To examine the relation between the emotional quality of an odor and its likelihood of identification, this study evaluates how normative emotion ratings based on the 3-dimensional affective space model (that includes valence, arousal, and dominance), using the Self-Assessment Manikin by Bradley and Lang (Bradley MM, Lang PJ. 1994. Measuring emotion: the Self-Assessment Manikin and the Semantic Differential. J Behav Ther Exp Psychiatry. 25(1):49-59.) and the Positive and Negative Affect Schedule (Watson D, Clark LA, Tellegen A. 1988. Development and validation of brief measures of positive and negative affect: the PANAS scales. J Pers Soc Psychol. 54(6):1063-1070.) predict the identification of odors in a multiple choice condition. The best fitting logistic regression model includes squared valence and dominance and thus, points to a significant role of specific emotional features of odors as a main clue for odor identification. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Do Masculine Men Smell Better? An Association Between Skin Color Masculinity and Female Preferences for Body Odor.

PubMed

Carrito, Mariana L; Santos, Isabel M; Alho, Laura; Ferreira, Jacqueline; Soares, Sandra C; Bem-Haja, Pedro; Silva, Carlos F; Perrett, David I

2017-03-01

A recent study claimed face skin color as a sexually dimorphic variable that influences attractiveness preferences in mate choice. Thereby, skin color may assume the role of a mate quality signal influencing attractiveness preferences. As body odor is linked to attractiveness, this study aimed to explore whether the odors of men with more masculine facial skin color would be evaluated more positively than odors from less masculine men. Female raters were presented with body odors of 18 men and were asked to rate them in various characteristics. Multilevel modeling revealed that the odors of the donors with more masculine color were rated not only as more attractive, more pleasant, and sexier, but also healthier. This indicates that odor associated with men with more masculine skin color is attractive, just as other sexually dimorphic traits. Furthermore, we found a negative relation between skin color masculinity and perceived odor maleness. Regarding this last finding, a new discussion is introduced with respect to the influence of cognitive stereotypes in odor judgments. Altogether, the study supports the possibility that chemosensory signals may be communicating signs of mate quality associated with masculinity. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Odorant-stimulated phosphoinositide signaling in mammalian olfactory receptor neurons

PubMed Central

Klasen, K.; Corey, E.A.; Kuck, F.; Wetzel, C.H.; Hatt, H.; Ache, B.W.

2009-01-01

Recent evidence has revived interest in the idea that phosphoinositides (PIs) may play a role in signal transduction in mammalian olfactory receptor neurons (ORNs). To provide direct evidence that odorants indeed activate PI signaling in ORNs, we used adenoviral vectors carrying two different fluorescently tagged probes, the pleckstrin homology (PH) domains of phospholipase Cδ1 (PLCδ1) and the general receptor of phosphoinositides (GRP1), to monitor PI activity in the dendritic knobs of ORNs in vivo. Odorants mobilized PI(4,5)P2/IP3 and PI(3,4,5)P3, the substrates and products of PLC and PI3K. We then measured odorant activation of PLC and PI3K in olfactory ciliary-enriched membranes in vitro using a phospholipid overlay assay and ELISAs. Odorants activated both PLC and PI3K in the olfactory cilia within 2 sec of odorant stimulation. Odorant-dependent activation of PLC and PI3K in the olfactory epithelium could be blocked by enzyme-specific inhibitors. Odorants activated PLC and PI3K with partially overlapping specificity. These results provide direct evidence that odorants indeed activate PI signaling in mammalian ORNs in a manner that is consistent with the idea that PI signaling plays a role in olfactory transduction. PMID:19781634

Odors enhance slow-wave activity in non-rapid eye movement sleep

PubMed Central

Perl, Ofer; Arzi, Anat; Sela, Lee; Secundo, Lavi; Holtzman, Yael; Samnon, Perry; Oksenberg, Arie; Sobel, Noam

2016-01-01

Most forms of suprathreshold sensory stimulation perturb sleep. In contrast, presentation of pure olfactory or mild trigeminal odorants does not lead to behavioral or physiological arousal. In fact, some odors promote objective and subjective measures of sleep quality in humans and rodents. The brain mechanisms underlying these sleep-protective properties of olfaction remain unclear. Slow oscillations in the electroencephalogram (EEG) are a marker of deep sleep, and K complexes (KCs) are an EEG marker of cortical response to sensory interference. We therefore hypothesized that odorants presented during sleep will increase power in slow EEG oscillations. Moreover, given that odorants do not drive sleep interruption, we hypothesized that unlike other sensory stimuli odorants would not drive KCs. To test these hypotheses we used polysomnography to measure sleep in 34 healthy subjects (19 women, 15 men; mean age 26.5 ± 2.5 yr) who were repeatedly presented with odor stimuli via a computer-controlled air-dilution olfactometer over the course of a single night. Each participant was exposed to one of four odorants, lavender oil (n = 13), vetiver oil (n = 5), vanillin (n = 12), or ammonium sulfide (n = 4), for durations of 5, 10, and 20 s every 9–15 min. Consistent with our hypotheses, we found that odor presentation during sleep enhanced the power of delta (0.5–4 Hz) and slow spindle (9–12 Hz) frequencies during non-rapid eye movement sleep. The increase was proportionate to odor duration. In addition, odor presentation did not modulate the occurrence of KCs. These findings imply a sleep-promoting olfactory mechanism that may deepen sleep through driving increased slow-frequency oscillations. PMID:26888107

Serial position effects in recognition memory for odors: a reexamination.

PubMed

Miles, Christopher; Hodder, Kathryn

2005-10-01

Seven experiments examined recognition memory for sequentially presented odors. Following Reed (2000), participants were presented with a sequence of odors and then required to identify an odor from the sequence in a test probe comprising 2 odors. The pattern of results obtained by Reed (2000, although statistically marginal) demonstrated enhanced recognition for odors presented at the start (primacy) and end (recency) of the sequence: a result that we failed to replicate in any of the experiments reported here. Experiments 1 and 3 were designed to replicate Reed (2000), employing five-item and seven-item sequences, respectively, and each demonstrated significant recency, with evidence of primacy in Experiment 3 only. Experiment 2 replicated Experiment 1, with reduced interstimulus intervals, and produced a null effect of serial position. The ease with which the odors could be verbally labeled was manipulated in Experiments 4 and 5. Nameable odors produced a null effect of serial position (Experiment 4), and hard-to-name odors produced a pronounced recency effect (Experiment 5); nevertheless, overall rates of recognition were remarkably similar for the two experiments at around 70%. Articulatory suppression reduced recognition accuracy (Experiment 6), but recency was again present in the absence of primacy. Odor recognition performance was immune to the effects of an interleaved odor (Experiment 7), and, again, both primacy and recency effects were absent. There was no evidence of olfactory fatigue: Recognition accuracy improved across trials (Experiment 1). It is argued that the results of the experiments reported here are generally consistent with that body of work employing hard-to-name visual stimuli, where recency is obtained in the absence of primacy when the retention interval is short.

Norepinephrine and Learning-Induced Plasticity in Infant Rat Olfactory System

PubMed Central

Sullivan, Regina M.; Wilson, Donald A.; Leon, Michael

2007-01-01

Postnatal olfactory learning produces both a conditioned behavioral response and a modified olfactory bulb neural response to the learned odor. The present report describes the role of norepinephrine (NE) on both of these learned responses in neonatal rat pups. Pups received olfactory classical conditioning training from postnatal days (PN) 1-18. Training consisted of 18 trials with an intertrial interval of 24 hr. For the experimental group, a trial consisted of a pairing of unconditioned stimulus (UCS, stroking/tactile stimulation) and the conditioned stimulus (CS, odor). Control groups received either only the CS (Odor only) or only the UCS (Stroke only). Within each training condition, pups were injected with either the NE β-receptor agonist isoproterenol (1, 20, or 4 mg/kg), the NE β-receptor antagonist propranolol (10, 20, 40 mg/kg), or saline 30 min prior to training. On day 20, pups received one of the following tests: (1) behavioral conditioned responding, (2) injection with 14C-2-deoxyglucase (2-DG) and exposed to the CS odor, or (3) tested for olfactory bulb mitral/tufted cell single-unit responses to the CS odor. The results indicated that training with either: (1) Odor-Stroke-Saline, (2) Odor-Stroke-lsoproterenol-Propranolol, or (3) Odor only-lsoproterenol (2 mg/kg) was sufficient to produce a learned behavioral odor preference, enhanced uptake of 14C-2-DG in the odor-specific foci within the bulb, and a modified output signal from the bulb as measured by single-cell recordings of mitral/tufted cells. Moreover, propranolol injected prior to Odor-Stroke training blocked the acquisition of both the learned behavior and olfactory bulb responses. PMID:2585063

Learning about natural variation of odor mixtures enhances categorization in early olfactory processing.

PubMed

Locatelli, Fernando F; Fernandez, Patricia C; Smith, Brian H

2016-09-01

Natural odors are typically mixtures of several chemical components. Mixtures vary in composition among odor objects that have the same meaning. Therefore a central 'categorization' problem for an animal as it makes decisions about odors in natural contexts is to correctly identify odor variants that have the same meaning and avoid variants that have a different meaning. We propose that identified mechanisms of associative and non-associative plasticity in early sensory processing in the insect antennal lobe and mammalian olfactory bulb are central to solving this problem. Accordingly, this plasticity should work to improve categorization of odors that have the opposite meanings in relation to important events. Using synthetic mixtures designed to mimic natural odor variation among flowers, we studied how honey bees learn about and generalize among floral odors associated with food. We behaviorally conditioned honey bees on a difficult odor discrimination problem using synthetic mixtures that mimic natural variation among snapdragon flowers. We then used calcium imaging to measure responses of projection neurons of the antennal lobe, which is the first synaptic relay of olfactory sensory information in the brain, to study how ensembles of projection neurons change as a result of behavioral conditioning. We show how these ensembles become 'tuned' through plasticity to improve categorization of odors that have the different meanings. We argue that this tuning allows more efficient use of the immense coding space of the antennal lobe and olfactory bulb to solve the categorization problem. Our data point to the need for a better understanding of the 'statistics' of the odor space. © 2016. Published by The Company of Biologists Ltd.

One antenna, two antennae, big antennae, small: total antennae length, not bilateral symmetry, predicts odor-tracking performance in the American cockroach Periplaneta americana.

PubMed

Lockey, Jacob K; Willis, Mark A

2015-07-01

Determining the location of a particular stimulus is often crucial to an animal's survival. One way to determine the local distribution of an odor is to make simultaneous comparisons across multiple sensors. If the sensors detect differences in the distribution of an odor in space, the animal can then steer toward the source. American cockroaches, Periplaneta americana, have 4 cm long antennae and are thought to track odor plumes using a spatial sampling strategy, comparing the amount of odor detected between these bilateral sensors. However, it is not uncommon for cockroaches to lose parts of their antennae and still track a wind-borne odor to its source. We examined whether bilateral odor input is necessary to locate an odor source in a wind-driven environment and how the loss of increasing lengths of the antennae affects odor tracking. The tracking performances of individuals with two bilaterally symmetrical antennae of decreasing length were compared with antennal length-matched individuals with one antenna. Cockroaches with one antenna were generally able to track an odor plume to its source. In fact, the performances of unilaterally antennectomized individuals were statistically identical to those of their bilaterally symmetrical counterparts when the combined length of both antennae equaled the length of the single antenna of the antennectomized individuals. This suggests that the total length of available antennae influences odor tracking performance more than any specific piece of antenna, and that they may be doing something more complex than a simple bilateral comparison between their antennae. The possibility of an antenna-topic map is discussed. © 2015. Published by The Company of Biologists Ltd.

A “Misfit” Theory of Spontaneous Conscious Odor Perception (MITSCOP): reflections on the role and function of odor memory in everyday life

PubMed Central

Köster, Egon P.; Møller, Per; Mojet, Jozina

2014-01-01

Our senses have developed as an answer to the world we live in (Gibson, 1966) and so have the forms of memory that accompany them. All senses serve different purposes and do so in different ways. In vision, where orientation and object recognition are important, memory is strongly linked to identification. In olfaction, the guardian of vital functions such as breathing and food ingestion, perhaps the most important (and least noticed and researched) role of odor memory is to help us not to notice the well-known odors or flavors in our everyday surroundings, but to react immediately to the unexpected ones. At the same time it provides us with a feeling of safety when our expectancies are met. All this happens without any smelling intention or conscious knowledge of our expectations. Identification by odor naming is not involved in this and people are notoriously bad at it. Odors are usually best identified via the episodic memory of the situation in which they once occurred. Spontaneous conscious odor perception normally only occurs in situations where attention is demanded, either because the inhaled air or the food smell is particularly good or particularly bad and people search for its source or because people want to actively enjoy the healthiness and pleasantness of their surroundings or food. Odor memory is concerned with novelty detection rather than with recollection of odors. In this paper, these points are illustrated with experimental results and their consequences for doing ecologically valid odor memory research are drawn. Furthermore, suggestions for ecologically valid research on everyday odor memory and some illustrative examples are given. PMID:24575059

Perceived annoyance from environmental odors and association with atmospheric ammonia levels in non-urban residential communities: a cross-sectional study

PubMed Central

2012-01-01

Objective Odor exposure is an environmental stressor that is responsible of many citizens complains about air pollution in non-urban areas. However, information about the exposure-response relation is scarce. One of the main challenges is to identify a measurable compound that can be related with odor annoyance responses. We investigated the association between regional and temporal variation of ammonia (NH3) concentrations in five Danish non-urban regions and environmental odor annoyance as perceived by the local residents. Methods A cross-sectional study where NH3 concentration was obtained from the national air quality monitoring program and from emission-dispersion modelling, and odor pollution perception from questionnaires. The exposure-response model was a sigmoid model. Linear regression analyses were used to estimate the model constants after equation transformations. The model was validated using leave-one-out cross validation (LOOCV) statistical method. Results About 45% of the respondents were annoyed by odor pollution at their residential areas. The perceived odor was characterized by all respondents as animal waste odor. The exposure-annoyance sigmoid model showed that the prevalence of odor annoyance was significantly associated with NH3 concentrations (measured and estimated) at the local air quality monitoring stations (p < 0.01,R2 = 0.99; and p < 0.05,R2 = 0.93; respectively). Prediction errors were below 5.1% and 20% respectively. The seasonal pattern of odor perception was associated with the seasonal variation in NH3 concentrations (p < 0.001, adjusted R2 = 0.68). Conclusion The results suggest that atmospheric NH3 levels at local air quality stations could be used as indicators of prevalence of odor annoyance in non-urban residential communities. PMID:22513250

Odors enhance slow-wave activity in non-rapid eye movement sleep.

PubMed

Perl, Ofer; Arzi, Anat; Sela, Lee; Secundo, Lavi; Holtzman, Yael; Samnon, Perry; Oksenberg, Arie; Sobel, Noam; Hairston, Ilana S

2016-05-01

Most forms of suprathreshold sensory stimulation perturb sleep. In contrast, presentation of pure olfactory or mild trigeminal odorants does not lead to behavioral or physiological arousal. In fact, some odors promote objective and subjective measures of sleep quality in humans and rodents. The brain mechanisms underlying these sleep-protective properties of olfaction remain unclear. Slow oscillations in the electroencephalogram (EEG) are a marker of deep sleep, and K complexes (KCs) are an EEG marker of cortical response to sensory interference. We therefore hypothesized that odorants presented during sleep will increase power in slow EEG oscillations. Moreover, given that odorants do not drive sleep interruption, we hypothesized that unlike other sensory stimuli odorants would not drive KCs. To test these hypotheses we used polysomnography to measure sleep in 34 healthy subjects (19 women, 15 men; mean age 26.5 ± 2.5 yr) who were repeatedly presented with odor stimuli via a computer-controlled air-dilution olfactometer over the course of a single night. Each participant was exposed to one of four odorants, lavender oil (n = 13), vetiver oil (n = 5), vanillin (n = 12), or ammonium sulfide (n = 4), for durations of 5, 10, and 20 s every 9-15 min. Consistent with our hypotheses, we found that odor presentation during sleep enhanced the power of delta (0.5-4 Hz) and slow spindle (9-12 Hz) frequencies during non-rapid eye movement sleep. The increase was proportionate to odor duration. In addition, odor presentation did not modulate the occurrence of KCs. These findings imply a sleep-promoting olfactory mechanism that may deepen sleep through driving increased slow-frequency oscillations. Copyright © 2016 the American Physiological Society.

Paradoxical Neurobehavioral Rescue by Memories of Early-Life Abuse: The Safety Signal Value of Odors Learned during Abusive Attachment

PubMed Central

Raineki, Charlis; Sarro, Emma; Rincón-Cortés, Millie; Perry, Rosemarie; Boggs, Joy; Holman, Colin J; Wilson, Donald A; Sullivan, Regina M

2015-01-01

Caregiver-associated cues, including those learned in abusive attachment, provide a sense of safety and security to the child. Here, we explore how cues associated with abusive attachment, such as maternal odor, can modify the enduring neurobehavioral effects of early-life abuse. Two early-life abuse models were used: a naturalistic paradigm, where rat pups were reared by an abusive mother; and a more controlled paradigm, where pups underwent peppermint odor-shock conditioning that produces an artificial maternal odor through engagement of the attachment circuit. Animals were tested for maternal odor preference in infancy, forced swim test (FST), social behavior, and sexual motivation in adulthood—in the presence or absence of maternal odors (natural or peppermint). Amygdala odor-evoked local field potentials (LFPs) via wireless electrodes were also examined in response to the maternal odors in adulthood. Both early-life abuse models induced preference for the maternal odors in infancy. In adulthood, these early-life abuse models produced FST deficits and decreased social behavior, but did not change sexual motivation. Presentation of the maternal odors rescued FST and social behavior deficits induced by early-life abuse and enhanced sexual motivation in all animals. In addition, amygdala LFPs from both abuse animal models showed unique activation within the gamma frequency (70–90 Hz) bands in response to the specific maternal odor present during early-life abuse. These results suggest that attachment-related cues learned during infancy have a profound ability to rescue neurobehavioral dysregulation caused by early-life abuse. Paradoxically, abuse-associated cues seem to acquire powerful and enduring antidepressive properties and alter amygdala modulation. PMID:25284320

Paradoxical neurobehavioral rescue by memories of early-life abuse: the safety signal value of odors learned during abusive attachment.

PubMed

Raineki, Charlis; Sarro, Emma; Rincón-Cortés, Millie; Perry, Rosemarie; Boggs, Joy; Holman, Colin J; Wilson, Donald A; Sullivan, Regina M

2015-03-01

Caregiver-associated cues, including those learned in abusive attachment, provide a sense of safety and security to the child. Here, we explore how cues associated with abusive attachment, such as maternal odor, can modify the enduring neurobehavioral effects of early-life abuse. Two early-life abuse models were used: a naturalistic paradigm, where rat pups were reared by an abusive mother; and a more controlled paradigm, where pups underwent peppermint odor-shock conditioning that produces an artificial maternal odor through engagement of the attachment circuit. Animals were tested for maternal odor preference in infancy, forced swim test (FST), social behavior, and sexual motivation in adulthood-in the presence or absence of maternal odors (natural or peppermint). Amygdala odor-evoked local field potentials (LFPs) via wireless electrodes were also examined in response to the maternal odors in adulthood. Both early-life abuse models induced preference for the maternal odors in infancy. In adulthood, these early-life abuse models produced FST deficits and decreased social behavior, but did not change sexual motivation. Presentation of the maternal odors rescued FST and social behavior deficits induced by early-life abuse and enhanced sexual motivation in all animals. In addition, amygdala LFPs from both abuse animal models showed unique activation within the gamma frequency (70-90 Hz) bands in response to the specific maternal odor present during early-life abuse. These results suggest that attachment-related cues learned during infancy have a profound ability to rescue neurobehavioral dysregulation caused by early-life abuse. Paradoxically, abuse-associated cues seem to acquire powerful and enduring antidepressive properties and alter amygdala modulation.

The human brain representation of odor identification.

PubMed

Kjelvik, Grete; Evensmoen, Hallvard R; Brezova, Veronika; Håberg, Asta K

2012-07-01

Odor identification (OI) tests are increasingly used clinically as biomarkers for Alzheimer's disease and schizophrenia. The aim of this study was to directly compare the neuronal correlates to identified odors vs. nonidentified odors. Seventeen females with normal olfactory function underwent a functional magnetic resonance imaging (fMRI) experiment with postscanning assessment of spontaneous uncued OI. An event-related analysis was performed to compare within-subject activity to spontaneously identified vs. nonidentified odors at the whole brain level, and in anatomic and functional regions of interest (ROIs) in the medial temporal lobe (MTL). Parameter estimate values and blood oxygenated level-dependent (BOLD) signal curves for correctly identified and nonidentified odors were derived from functional ROIs in hippocampus, entorhinal, piriform, and orbitofrontal cortices. Number of activated voxels and max parameter estimate values were obtained from anatomic ROIs in the hippocampus and the entorhinal cortex. At the whole brain level the correct OI gave rise to increased activity in the left entorhinal cortex and secondary olfactory structures, including the orbitofrontal cortex. Increased activation was also observed in fusiform, primary visual, and auditory cortices, inferior frontal plus inferior temporal gyri. The anatomic MTL ROI analysis showed increased activation in the left entorhinal cortex, right hippocampus, and posterior parahippocampal gyri in correct OI. In the entorhinal cortex and hippocampus the BOLD signal increased specifically in response to identified odors and decreased for nonidentified odors. In orbitofrontal and piriform cortices both identified and nonidentified odors gave rise to an increased BOLD signal, but the response to identified odors was significantly greater than that for nonidentified odors. These results support a specific role for entorhinal cortex and hippocampus in OI, whereas piriform and orbitofrontal cortices are active in both smelling and OI. Moreover, episodic as well as semantic memory systems appeared to support OI.

Mere odor exposure learning in the rat neonate immediately after birth and one day later

PubMed Central

Miller, Stacie S.; Spear, Norman E.

2011-01-01

Rat pups are more resistant to retroactive associative interference 3 hrs after birth than 24 hours later (Cheslock, Sanders, & Spear, 2004). The present experiments tested the effect of age, retention interval and dam presence during the retention interval on odor-induced motor activity subsequent to mere odor exposure. Rats were exposed to an hour of odor immediately after birth or approximately one day later and tested after a given retention interval (3 hrs or 27 hrs [Exp 1]; 0, 30, 75, or 180 min [Exp. 2]). They spent the retention interval either in the presence or absence of a foster dam (Exp. 1 and 3). After the retention interval, pups were tested in a four-minute activity test including a two-minute baseline period and two minutes of odor exposure. Overall activity was scored during tape-playback. Odor-exposed pups were more active than non-exposed pups during reexposure to the odor during testing, but this was true only for P0 pups. In contrast, P1 pups without prior odor exposure were active during testing and behaviorally quieted in the presence of the odor they were previously exposed to. Though one day apart, newborn rats just hours old lack many of the experiences that a one day old has had including nursing, huddling, and being groomed. These experiences are associated with, among other stimuli, a barrage of olfactory cues (e.g., colostrum, saliva, dander, feces, and urine). P0 and P1 pups also differ in their proximity from the birthing experience and associated neurochemical changes. The age-related pattern of responding to odors based on previous odor exposure was discussed in relation to these and other possibilities. PMID:20411590

Mere odor exposure learning in the rat neonate immediately after birth and 1 day later.

PubMed

Miller, Stacie S; Spear, Norman E

2010-05-01

Rat pups are more resistant to retroactive associative interference 3 hr after birth than 24 hr later [Cheslock et al. [2004] Developmental Science, 7, 581-598]. The present experiments tested the effect of age, retention interval and dam presence during the retention interval on odor-induced motor activity subsequent to mere odor exposure. Rats were exposed to an hour of odor immediately after birth or approximately 1 day later and tested after a given retention interval (3 or 27 hr [Exp 1]; 0, 30, 75, or 180 min [Exp. 2]). They spent the retention interval either in the presence or absence of a foster dam (Exp. 1 and 3). After the retention interval, pups were tested in a 4-min activity test including a 2-min baseline period and 2 min of odor exposure. Overall activity was scored during tape-playback. Odor-exposed pups were more active than nonexposed pups during reexposure to the odor during testing, but this was true only for P0 pups. In contrast, P1 pups without prior odor exposure were active during testing and behaviorally quieted in the presence of the odor they were previously exposed to. Though 1 day apart, newborn rats just hours old lack many of the experiences that a 1-day-old has had including nursing, huddling, and being groomed. These experiences are associated with, among other stimuli, a barrage of olfactory cues (e.g., colostrum, saliva, dander, feces, and urine). P0 and P1 pups also differ in their proximity from the birthing experience and associated neurochemical changes. The age-related pattern of responding to odors based on previous odor exposure was discussed in relation to these and other possibilities.

The Accessory Olfactory System Facilitates the Recovery of the Attraction to Familiar Volatile Female Odors in Male Mice.

PubMed

Muroi, Yoshikage; Nishimura, Masakazu; Ishii, Toshiaki

2017-10-31

Odors in female mice induce sexual arousal in male mice. Repeated exposure to female odors attenuates male attraction, which recovers when the odors are removed. The neuronal mechanisms for the recovery of male attraction have not been clarified. In this study, we examined how olfactory systems are involved in the recovery of male attraction to female odors following habituation in mice. Presentation with volatile female odors for 5 min induced habituation in males. To evaluate male attraction to familiar volatile female odors, we measured the duration for investigating volatile female odors from the same female mouse, which was presented twice for 5 min with 1-, 3-, or 5-min interval. Intranasal irrigation with ZnSO4 solution almost completely suppressed investigating behavior, indicating that the main olfactory system is indispensable for inducing the attraction to volatile female odors. In contrast, removal of the vomeronasal organ, bilateral lesions of the accessory olfactory bulb (AOB), or pharmacological blockage of neurotransmission in the AOB did not affect the investigation time at the first odor presentation. However, each one of the treatments decreased the investigation time in the second presentation, compared to that in the first presentation, at longer intervals than control treatment, indicating that the disturbance of neurotransmission in the accessory olfactory system delayed the recovery of the attraction attenuated by the first presentation. These results suggest that the accessory olfactory system facilitates the recovery of the attraction to familiar volatile female odors in male mice. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A Beta Oscillation Network in the Rat Olfactory System During a 2-Alternative Choice Odor Discrimination Task

PubMed Central

Beshel, Jennifer

2010-01-01

We previously showed that in a two-alternative choice (2AC) task, olfactory bulb (OB) gamma oscillations (∼70 Hz in rats) were enhanced during discrimination of structurally similar odorants (fine discrimination) versus discrimination of dissimilar odorants (coarse discrimination). In other studies (mostly employing go/no-go tasks) in multiple labs, beta oscillations (15–35 Hz) dominate the local field potential (LFP) signal in olfactory areas during odor sampling. Here we analyzed the beta frequency band power and pairwise coherence in the 2AC task. We show that in a task dominated by gamma in the OB, beta oscillations are also present in three interconnected olfactory areas (OB and anterior and posterior pyriform cortex). Only the beta band showed consistently elevated coherence during odor sniffing across all odor pairs, classes (alcohols and ketones), and discrimination types (fine and coarse), with stronger effects in first than in final criterion sessions (>70% correct). In the first sessions for fine discrimination odor pairs, beta power for incorrect trials was the same as that for correct trials for the other odor in the pair. This pattern was not repeated in coarse discrimination, in which beta power was elevated for correct relative to incorrect trials. This difference between fine and coarse odor discriminations may relate to different behavioral strategies for learning to differentiate similar versus dissimilar odors. Phase analysis showed that the OB led both pyriform areas in the beta frequency band during odor sniffing. We conclude that the beta band may be the means by which information is transmitted from the OB to higher order areas, even though task specifics modify dominance of one frequency band over another within the OB. PMID:20538778

Predicting human olfactory perception from chemical features of odor molecules.

PubMed

Keller, Andreas; Gerkin, Richard C; Guan, Yuanfang; Dhurandhar, Amit; Turu, Gabor; Szalai, Bence; Mainland, Joel D; Ihara, Yusuke; Yu, Chung Wen; Wolfinger, Russ; Vens, Celine; Schietgat, Leander; De Grave, Kurt; Norel, Raquel; Stolovitzky, Gustavo; Cecchi, Guillermo A; Vosshall, Leslie B; Meyer, Pablo

2017-02-24

It is still not possible to predict whether a given molecule will have a perceived odor or what olfactory percept it will produce. We therefore organized the crowd-sourced DREAM Olfaction Prediction Challenge. Using a large olfactory psychophysical data set, teams developed machine-learning algorithms to predict sensory attributes of molecules based on their chemoinformatic features. The resulting models accurately predicted odor intensity and pleasantness and also successfully predicted 8 among 19 rated semantic descriptors ("garlic," "fish," "sweet," "fruit," "burnt," "spices," "flower," and "sour"). Regularized linear models performed nearly as well as random forest-based ones, with a predictive accuracy that closely approaches a key theoretical limit. These models help to predict the perceptual qualities of virtually any molecule with high accuracy and also reverse-engineer the smell of a molecule. Copyright © 2017, American Association for the Advancement of Science.

Fabrication of Activated Rice Husk Charcoal by Slip Casting as a Hybrid Material for Water Filter Aid

NASA Astrophysics Data System (ADS)

Tuaprakone, T.; Wongphaet, N.; Wasanapiarnpong, T.

2011-04-01

Activated charcoal has been widely used as an odor absorbent in household and water purification industry. Filtration equipment for drinking water generally consists of four parts, which are microporous membrane (porous alumina ceramic or diatomite, or porous polymer), odor absorbent (activated carbon), hard water treatment (ion exchange resin), and UV irradiation. Ceramic filter aid is usually prepared by slip casting of alumina or diatomite. The membrane offers high flux, high porosity and maximum pore size does not exceed 0.3 μm. This study investigated the fabrication of hybrid activated charcoal tube for water filtration and odor absorption by slip casting. The suitable rice husk charcoal and water ratio was 48 to 52 wt% by weight with 1.5wt% (by dry basis) of CMC binder. The green rice husk charcoal bodies were dried and fired between 700-900 °C in reduction atmosphere. The resulting prepared slip in high speed porcelain pot for 60 min and sintered at 700 °C for 1 h showed the highest specific surface area as 174.95 m2/g. The characterizations of microstructure and pore size distribution as a function of particle size were investigated.

Rabbit Neonates and Human Adults Perceive a Blending 6-Component Odor Mixture in a Comparable Manner

PubMed Central

Sinding, Charlotte; Thomas-Danguin, Thierry; Chambault, Adeline; Béno, Noelle; Dosne, Thibaut; Chabanet, Claire; Schaal, Benoist; Coureaud, Gérard

2013-01-01

Young and adult mammals are constantly exposed to chemically complex stimuli. The olfactory system allows for a dual processing of relevant information from the environment either as single odorants in mixtures (elemental perception) or as mixtures of odorants as a whole (configural perception). However, it seems that human adults have certain limits in elemental perception of odor mixtures, as suggested by their inability to identify each odorant in mixtures of more than 4 components. Here, we explored some of these limits by evaluating the perception of three 6-odorant mixtures in human adults and newborn rabbits. Using free-sorting tasks in humans, we investigated the configural or elemental perception of these mixtures, or of 5-component sub-mixtures, or of the 6-odorant mixtures with modified odorants' proportion. In rabbit pups, the perception of the same mixtures was evaluated by measuring the orocephalic sucking response to the mixtures or their components after conditioning to one of these stimuli. The results revealed that one mixture, previously shown to carry the specific odor of red cordial in humans, was indeed configurally processed in humans and in rabbits while the two other 6-component mixtures were not. Moreover, in both species, such configural perception was specific not only to the 6 odorants included in the mixture but also to their respective proportion. Interestingly, rabbit neonates also responded to each odorant after conditioning to the red cordial mixture, which demonstrates their ability to perceive elements in addition to configuration in this complex mixture. Taken together, the results provide new insights related to the processing of relatively complex odor mixtures in mammals and the inter-species conservation of certain perceptual mechanisms; the results also revealed some differences in the expression of these capacities between species putatively linked to developmental and ecological constraints. PMID:23341948

Detection of smoldering combustion of coal with an odor meter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, J.C.

1995-05-01

A commercially available odor meter was evaluated as a detector of smoldering coal combustion, and compared with incipient carbon monoxide (CO) and hydrogen sulfide (H{sub 2}S) detection and a commercially available ionization-type smoke detector. Ten smoldering coal combustion experiments were conducted. For eight of the experiments, Pittsburgh seam coal with an average particle diameter of approximately 5 cm was heated by embedded electrical strip heaters. For two of the experiments mine size Pittsburgh seam coal was heated. Heating rates of 0.5, 0.8, and 1.1. kw were selected to provide experimental conditions characteristic of very slow and moderately fast heating formore » coal sample mass between 3 and 10 kg. It was found that the odor meter and smoke detector alarm had a good correlation, with the odor meter alarm occurring prior to the smoke alarm in four of the ten experiments. The odor meter gave an increase in its output signal above ambient equivalent to detecting 1 ppm of H{sub 2}S (ten times the odor threshold of H{sub 2}S) as an alarm value. This observed odor meter response occurred prior to the electrochemical detection of H{sub 2}S for five of the six experiments for which it was evaluated. In all six experiments for which the smoke optical density was evaluated, it was less than 0.023 m{sup -1} prior to the odor meter reaching alarm. In each of the eight experiments with 5 cm diameter coal particles the CO exceeded 5 ppm at odor meter alarm, while for the two experiments with mine size coal the CO was less than 3 ppm at odor meter alarm. The odor meter, as tested, is not a significant improvement over smoke and CO detectors. Because the odor meter responds to a variety of chemical compounds, with suitable modification and increased sensitivity it may be useful for detection of mine fires and thereby enhance mine safety.« less

Lesions that functionally disconnect the anterior and posterodorsal sub-regions of the medial amygdala eliminate opposite-sex odor preference in male Syrian hamsters (Mesocricetus auratus)

PubMed Central

Maras, Pamela M.; Petrulis, Aras

2009-01-01

In many rodent species, such as Syrian hamsters, reproductive behavior requires neural integration of chemosensory information and steroid hormone cues. The medial amygdala processes both of these signals through anatomically distinct sub-regions; the anterior region (MeA) receives substantial chemosensory input, but contains few steroid receptor-labeled neurons, whereas the posterodorsal region (MePD) receives less chemosensory input, but contains a dense population of steroid receptors. Importantly, these sub-regions have considerable reciprocal connections, and the goal of this experiment was therefore to determine whether interactions between MeA and MePD are required for male hamsters’ preference to investigate female over male odors. To functionally disconnect MeA and MePD, males received unilateral lesions of MeA and MePD within opposite brain hemispheres. Control males received either unilateral lesions of MeA and MePD within the same hemisphere or sham surgery. Odor preferences were measured using a 3-choice apparatus, which simultaneously presented female, male and clean odor stimuli; all tests were done under conditions that either prevented or allowed contact with the odor sources. Under non-contact conditions, males with asymmetrical lesions investigated female and male odors equally, whereas males in both control groups preferred to investigate female odors. Under contact conditions, all groups investigated female odors longer than male odors, although males with asymmetrical lesions displayed decreased investigation of female odors compared to sham males. These data suggest that MeA-MePD interactions are critical for processing primarily the volatile components of social odors and highlight the importance of input from the main olfactory system to these nuclei in the regulation of reproductive behavior. More broadly, these results support the role of the medial amygdala in integrating chemosensory and hormone information, a process that may underlie social odor processing in a variety of behavioral contexts. PMID:19931356

Attraction thresholds and sex discrimination of urinary odorants in male and female aromatase knockout (ArKO) mice.

PubMed

Pierman, Sylvie; Douhard, Quentin; Balthazart, Jacques; Baum, Michael J; Bakker, Julie

2006-01-01

We previously found that both male and female aromatase knockout (ArKO) mice, which cannot synthesize estrogens due to a targeted mutation of the aromatase gene, showed less investigation of volatile body odors from anesthetized conspecifics of both sexes in Y-maze tests. We now ask whether ArKO mice are in fact capable of discriminating between and/or responding to volatile odors. Using habituation/dishabituation tests, we found that gonadectomized ArKO and wild-type (WT) mice of both sexes, which were tested without any sex hormone replacement, reliably distinguished between undiluted volatile urinary odors of either adult males or estrous females versus deionized water as well as between these two urinary odors themselves. However, ArKO mice of both sexes were less motivated than WT controls to investigate same-sex odors when they were presented last in the sequence of stimuli. In a second experiment, we compared the ability of ArKO and WT mice to respond to decreasing concentrations of either male or female urinary odors. We found a clear-cut sex difference in urinary odor attraction thresholds among WT mice: WT males failed to respond to urine dilutions higher than 1:20 by volume, whereas WT females continued to respond to urine dilutions up to 1:80. Male ArKO mice resembled WT females in their ability to respond to lower concentrations of urinary odors, raising the possibility that the observed sex difference among WT mice in urine attraction thresholds results from the perinatal actions of estrogen in the male nervous system. Female ArKO mice failed to show significant dishabituation responses to two (1:20 and 1:80) dilutions of female urine, perhaps, again, because of a reduced motivation to investigate less salient, same-sex urinary odors. Previously observed deficits in the preference of ArKO male and female mice to approach volatile body odors from conspecifics of either sex cannot be attributed to an inability of ArKO subjects to discriminate these odors according to sex but instead may reflect a deficient motivation to approach same-sex odors, especially when their concentration is low.

Advanced waste management technology evaluation

NASA Technical Reports Server (NTRS)

Couch, H.; Birbara, P.

1996-01-01

The purpose of this program is to evaluate the feasibility of steam reforming spacecraft wastes into simple recyclable inorganic salts, carbon dioxide and water. Model waste compounds included cellulose, urea, methionine, Igapon TC-42, and high density polyethylenes. These are compounds found in urine, feces, hygiene water, etc. The gasification and steam reforming process used the addition of heat and low quantities of oxygen to oxidize and reduce the model compounds.The studied reactions were aimed at recovery of inorganic residues that can be recycled into a closed biologic system. Results indicate that even at very low concentrations of oxygen (less than 3%) the formation of a carbonaceous residue was suppressed. The use of a nickel/cobalt reforming catalyst at reaction temperature of 1600 degrees yielded an efficient destruction of the organic effluents, including methane and ammonia. Additionally, the reforming process with nickel/cobalt catalyst diminished the noxious odors associated with butyric acid, methionine and plastics.

Bioconversion of L-phenylalanine to 2-phenylethanol by the novel stress-tolerant yeast Candida glycerinogenes WL2002-5

PubMed Central

Lu, Xinyao; Wang, Yuqin; Zong, Hong; Ji, Hao; Zhuge, Bin; Dong, Zhuoli

2016-01-01

ABSTRACT 2-Phenylethanol (2-PE) is a high value aromatic alcohol with a rose-like odor that is utilized in the cosmetics and other industries. Although the chemical routes of 2-PE production have been altered by some microbial transformation processes, the poor tolerance to organic solvents of these microorganisms has limited the 2-PE yield. In this study, the stress-tolerant yeast Candida glycerinogenes WL2002-5 showed a 2-PE tolerance to 4 g/l, which is the highest reported to date. Moreover, the 2-PE titer in a batch fermentation from L-phenylalanine reached 5g/l, which is the highest level achieved by fermentation without in situ product recovery. These results suggest C. glycerinogenes WL2002-5 is a robust strain for the bioproduction of 2-PE with potential for commercial exploitation. PMID:27435817