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Scientific Reports Nov 2022Deciphering the relationship between molecules, olfactory receptors (ORs) and corresponding odors remains a challenging task. It requires a comprehensive identification...
Deciphering the relationship between molecules, olfactory receptors (ORs) and corresponding odors remains a challenging task. It requires a comprehensive identification of ORs responding to a given odorant. With the recent advances in artificial intelligence and the growing research in decoding the human olfactory perception from chemical features of odorant molecules, the applications of advanced machine learning have been revived. In this study, Convolutional Neural Network (CNN) and Graphical Convolutional Network (GCN) models have been developed on odorant molecules-odors and odorant molecules-olfactory receptors using a large set of 5955 molecules, 160 odors and 106 olfactory receptors. The performance of such models is promising with a Precision/Recall Area Under Curve of 0.66 for the odorant-odor and 0.91 for the odorant-olfactory receptor GCN models respectively. Furthermore, based on the correspondence of odors and ORs associated for a set of 389 compounds, an odor-olfactory receptor pairwise score was computed for each odor-OR combination allowing to suggest a combinatorial relationship between olfactory receptors and odors. Overall, this analysis demonstrate that artificial intelligence may pave the way in the identification of the smell perception and the full repertoire of receptors for a given odorant molecule.
Topics: Humans; Artificial Intelligence; Odorants; Olfactory Perception; Olfactory Receptor Neurons; Receptors, Odorant; Smell
PubMed: 36335231
DOI: 10.1038/s41598-022-23176-y -
Frontiers in Neural Circuits 2024In the mouse olfactory system, odor information is converted to a topographic map of activated glomeruli in the olfactory bulb (OB). Although the arrangement of... (Review)
Review
In the mouse olfactory system, odor information is converted to a topographic map of activated glomeruli in the olfactory bulb (OB). Although the arrangement of glomeruli is genetically determined, the glomerular structure is plastic and can be modified by environmental stimuli. If the pups are exposed to a particular odorant, responding glomeruli become larger recruiting the dendrites of connecting projection neurons and interneurons. This imprinting not only increases the sensitivity to the exposed odor, but also imposes the positive quality on imprinted memory. External odor information represented as an odor map in the OB is transmitted to the olfactory cortex (OC) and amygdala for decision making to elicit emotional and behavioral outputs using two distinct neural pathways, innate and learned. Innate olfactory circuits start to work right after birth, whereas learned circuits become functional later on. In this paper, the recent progress will be summarized in the study of olfactory circuit formation and odor perception in mice. We will also propose new hypotheses on the timing and gating of olfactory circuit activity in relation to the respiration cycle.
Topics: Animals; Mice; Sensation; Smell; Odorants; Amygdala; Perception
PubMed: 38434487
DOI: 10.3389/fncir.2024.1342576 -
Journal of Wound Care Oct 2017Malodorous wounds can be distressing for patients and their families, negatively impacting on quality-of-life outcomes. For health professionals malodorous wounds can... (Review)
Review
Malodorous wounds can be distressing for patients and their families, negatively impacting on quality-of-life outcomes. For health professionals malodorous wounds can also cause distress manifesting in feelings of disgust when faced with a wound emitting an unpleasant or repulsive odour. There has been investigation into the management of controlling odour particularly in relation to fungating wounds. However, there is limited research that explores techniques for early identification and recognition of wound odours that may be indicative of infection. Electronic nose technology has received some attention, but to date has not been integrated into either diagnostics of infection in wounds or education of health professionals to prepare them for the realities of clinical practice.
Topics: Early Diagnosis; Electronic Nose; Humans; Odorants; Wound Infection
PubMed: 28976829
DOI: 10.12968/jowc.2017.26.10.577 -
Journal of Hazardous Materials Oct 2022The simultaneous treatment of HS and NH typical odours by plasma was investigated and the co-treatment of both was found to have a facilitating effect the conversion....
The simultaneous treatment of HS and NH typical odours by plasma was investigated and the co-treatment of both was found to have a facilitating effect the conversion. The degradation efficiency and by-product emissions of single plasma technology and plasma co-catalytic two-stage technology were compared and the degradation mechanism was further analyzed. The results show that in the single plasma technology conversion experiment, the conversion rate of the treated odours mixture is higher than that of the treated single odours, and the by-product emissions of SO and NO are also reduced due to the reaction of intermediate products and by-products during the reaction process. The absolute removal of the odours mixture is optimal when treating at a gas flow rate of 6 L/min, a voltage of 16 kV and a frequency of 200 Hz. The M(Ce,Cu)-Mn/13X loaded catalyst was synthesized by co-precipitation method. Under the conditions of gas flow rate of 3-7 L/min, the efficiency of HS and NH removal and the reduction of by-product emission were ranked as: uncatalyzed > Cu-Mn/13X > Ce-Mn/13X, which proved that Ce-Mn/13X showed better catalytic activity and application value.
Topics: Catalysis; Gases; Odorants; Oxidation-Reduction
PubMed: 36007372
DOI: 10.1016/j.jhazmat.2022.129751 -
International Journal of Environmental... Jan 2022People living on both sides of the German-Czech border are subject to episodes of odor air pollution. A joint German-Czech air sampling and risk assessment project was...
People living on both sides of the German-Czech border are subject to episodes of odor air pollution. A joint German-Czech air sampling and risk assessment project was established to identify the substances responsible and their sources. Twenty-four volunteer study participants, 14 from the NW Czech Republic and 10 from Germany (Saxony) reported odors and collected canister samples during sampling periods in winter 2017 and 2018 and autumn 2018. Canister samples and passive samplers were analyzed for volatile organic compounds (VOCs) and passive samplers were analyzed for VOCs and carbonyls. OAVs (Odor Activity Values) and back trajectories were calculated with the aim of identifying the odor sources. Calculated OAVs were in excellent agreement with perceived smells close to an oil processing plant. Odorants identified in fifty canister samples during odor episodes and carbonyl measurements close to the edible oil processing plant were used for health evaluation. Odors reported by participants in Saxony frequently differed from those reported by participants in the Czech Republic. This suggests that certain sources of odor lying on either side of the border only affect that side and not the other with similar considerations regarding health effects. VOCs, including carbonyls, were also sampled at two relatively remote locations during winters of 2017 and 2018; two main sources of odorous compounds were identified at these sites. Analysis of samples taken at sampling sites shows that VOC air pollution and, to a lesser extent carbonyl pollution, originate from both industrial and local sources. Even though levels of sampled substances were not associated with acute effects at any site, long-term exposures to selected compounds could be cause for concern for carcinogenicity at some sites. Odors in Seiffen were associated with carcinogenic compounds in can samples. Although not necessarily representative of long-term exposures to the compounds studied, results such as these suggest that further study is needed to better quantify long-term exposure to potentially harmful compounds, and to either confirm or deny the existence of substantive health risk.
Topics: Air Pollutants; Czech Republic; Environmental Monitoring; Humans; Odorants; Risk Assessment; Social Participation; Volatile Organic Compounds
PubMed: 35162316
DOI: 10.3390/ijerph19031296 -
Biology Open Apr 2022Chemical communication plays a major role in social interactions. Cancer, by inducing changes in body odours, may alter interactions between individuals. In the...
Chemical communication plays a major role in social interactions. Cancer, by inducing changes in body odours, may alter interactions between individuals. In the framework of research targeting non-invasive methods to detect early stages of cancer development, this study asked whether untrained mice could detect odour changes in cancerous congeners. If yes, were they able to detect cancer at an early developmental stage? Did it influence female preference? Did variations in volatile organic components of the odour source paralleled mice behavioural responses? We used transgenic mice strains developing or not lung cancer upon antibiotic ingestion. We sampled soiled bedding of cancerous mice (CC) and not cancerous mice (NC), at three experimental conditions: before (T0), early stage (T2) and late stage (T12) of cancer development. Habituation/generalisation and two-way preference tests were performed where soiled beddings of CC and NC mice were presented to wild-derived mice. The composition and relative concentration of volatile organic components (VOC) in the two stimuli types were analysed. Females did not show directional preference at any of the experimental conditions, suggesting that cancer did not influence their choice behaviour. Males did not discriminate between CC and NC stimuli at T0 but did so at T2 and T12, indicating that wild-derived mice could detect cancer at an early stage of development. Finally, although the VOC bouquet differed between CC and NC it did not seem to parallel the observed behavioural response suggesting that other types of odorant components might be involved in behavioural discrimination between CC and NC mice.
Topics: Animals; Female; Male; Mice; Neoplasms; Odorants; Volatile Organic Compounds
PubMed: 35403195
DOI: 10.1242/bio.059208 -
Current Biology : CB Apr 2021The ability to group sensory stimuli into categories is crucial for efficient interaction with a rich and ever-changing environment. In olfaction, basic features of...
The ability to group sensory stimuli into categories is crucial for efficient interaction with a rich and ever-changing environment. In olfaction, basic features of categorical representation of odors were observed as early as in the olfactory bulb (OB). Categorical representation was described in mitral cells (MCs) as sudden transitions in responses to odors that were morphed along a continuum. However, it remains unclear to what extent such response dynamics actually reflect perceptual categories and decisions therein. Here, we tested the role of learning on category formation in the mouse OB, using in vivo two-photon calcium imaging and behavior. We imaged MC responses in naive mice and in awake behaving mice as they learned two tasks with different classification logic. In one task, a one-decision-boundary task, animals learned to classify odor mixtures based on the dominant compound in the mixtures. As expected, categorical representation of odors, which was evident already in naive animals, further increased following learning. In a second task, a multi-decision-boundary task, animals learned to classify odors independent of their chemical similarity. Here, odor discrimination was based on the meaning ascribed to them (either rewarding or not). Following the multi-decision-boundary task, odor representations by MCs reorganized according to the odor value in the new category. This functional reorganization was also reflected as a shift from predominantly excitatory odor responses to predominantly inhibitory odor responses. Our data show that odor representations by MCs are flexible, are shaped by task demands, and carry category-related information.
Topics: Animals; Learning; Mice; Odorants; Olfactory Bulb; Olfactory Perception; Reward; Smell
PubMed: 33571434
DOI: 10.1016/j.cub.2021.01.063 -
Animal Health Research Reviews Jun 2021Odors may be pleasant or unpleasant and in practice, pleasant odors are attractive while unpleasant odors are repellent. However, an odor that is noxious to one species... (Review)
Review
Odors may be pleasant or unpleasant and in practice, pleasant odors are attractive while unpleasant odors are repellent. However, an odor that is noxious to one species may be attractive to another. Plants, predators, and pathogens may enhance their transmission by manipulating these signals. This may be especially significant when odors attract arthropod disease vectors. Odor detection may also be important in small prey species for evasion of macropredators such as large carnivores. Conversely, pleasant odors may identify family members, parents, or sexual partners. They may also generate signals of good health or fitness and contribute to the process of mate selection. In this review, we seek to integrate these odor-driven processes into a coherent pattern of behaviors that serve to complement the innate and adaptive immune systems. It may be considered the 'behavioral immune system'.
Topics: Animals; Emotions; Immune System; Odorants; Smell
PubMed: 33926605
DOI: 10.1017/S1466252320000262 -
Scientific Reports Oct 2017Alexithymia is a psychological construct characterized by deficits in processing emotional stimuli. However, little is known about the processing of odours in...
Alexithymia is a psychological construct characterized by deficits in processing emotional stimuli. However, little is known about the processing of odours in alexithymia, even though there is extensive proof that emotion and olfaction are closely linked. The present study is aimed at investigating how alexithymic individuals process emotions conveyed by odors. Emotional responses to unpleasant, neutral odors and clean air were collected through self-report ratings and psychophysiological measures in a sample of 62 healthy participants with high (HA), medium (MA) and low (LA) levels of alexithymia. Moreover, participants performed tests on odors identification and threshold and completed questionnaires assessing olfactory imagery and awareness. Two main results have been found: first, HA and MA groups showed altered physiological responses to odors, compared to LA, while no differences among the groups were observed in odor ratings; and second, affective and cognitive alexithymia components were differently associated with the performance on olfactory tests, skin conductance response to odors, reaction times in the rating task, and scores on olfactory questionnaires. We conclude that alexithymia is characterized by altered physiological reactions to olfactory stimuli; moreover, we stress the importance of evaluating the different alexithymia components since they affect emotional stimuli processing in different ways.
Topics: Adult; Affective Symptoms; Case-Control Studies; Emotions; Female; Humans; Male; Odorants; Personality; Self Report
PubMed: 29074970
DOI: 10.1038/s41598-017-14404-x -
Chemosphere May 2021Odorant degrading carboxylesterases (CXEs) play key roles in the process of odor signal reception via degrading ester odorants. But the functional mechanisms of CXEs in...
Odorant degrading carboxylesterases (CXEs) play key roles in the process of odor signal reception via degrading ester odorants. But the functional mechanisms of CXEs in modulating insect behaviors are unclear. Herein, we studied the roles that CXEs played in mating, foraging, and signal receptions of sex pheromones and host volatiles in Grapholita molesta. As a result, 23 candidate CXEs were identified by transcriptome analysis of G. molesta. The GmolCXE1 and 5 highly expressed in the antennae of male moths and GmolCXE14 and 21 abundantly expressed in larval heads, were significantly upregulated after exposure with odors from female adults or fresh ripe fruits respectively. After knockdown of GmolCXE1 and 5, or GmolCXE14 and 21 by RNA interference, the behavioral responses of G. molesta to ester sex pheromones or host volatiles were decreased, by exhibiting an inhibited searching behavior of G. molesta for females or fruits, respectively. Then evidence form GC-MS analysis, showed that the protein GmolCXE1 and GmolCXE5 could metabolize the sex pheromone components (Z/E)-8-dodecenyl acetate to their metabolites products (Z/E)-8-dodecenol, and that GmolCXE14 and GmolCXE21 could metabolize ethyl butanoate and ethyl hexanoate of ripe pears. In addition, fluorescent binding assays verified that GmolCXEs could degrade the free ester odor molecules, but not degrade the odor molecules protected by odorant-binding proteins. Our study not only demonstrated CXEs modulated the mating and foraging behaviors of G. molesta through inactivation of ester sex pheromone and host volatiles, but also discovered great potential molecular targets to develop behavioral inhibitors for pest management.
Topics: Animals; Carboxylic Ester Hydrolases; Female; Insect Proteins; Larva; Male; Moths; Odorants
PubMed: 33757271
DOI: 10.1016/j.chemosphere.2020.128647