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International Journal of Cosmetic... Aug 2011Body malodour, including foot odour, suppresses social interaction by diminishing self-confidence and accelerating damage to the wearer's clothes and shoes. Most... (Review)
Review
Body malodour, including foot odour, suppresses social interaction by diminishing self-confidence and accelerating damage to the wearer's clothes and shoes. Most treatment agents, including aluminium anti-perspirant salts, inhibit the growth of malodourous bacteria. These metallic salts also reduce sweat by blocking the excretory ducts of sweat glands, minimizing the water source that supports bacterial growth. However, there are some drawback effects that limit the use of aluminium anti-perspirant salts. In addition, over-the-counter anti-perspirant and deodourant products may not be sufficiently effective for heavy sweaters, and strong malodour producers. Body odour treatment agents are rarely mentioned in the literature compared with other cosmetic ingredients. This review briefly summarizes the relationship among sweat, skin bacteria, and body odour; describes how odourous acids, thiols, and steroids are formed; and discusses the active ingredients, including metallic salts and herbs, that are used to treat body odour. A new class of ingredients that function by regulating the release of malodourants will also be described. These ingredients do not alter the balance of the skin flora.
Topics: Acids; Administration, Topical; Antiperspirants; Cosmetics; Humans; Odorants; Steroids; Sulfhydryl Compounds; Sweat Glands
PubMed: 21401651
DOI: 10.1111/j.1468-2494.2011.00649.x -
Chemical Senses Mar 2017The vast number of detectable odors makes matching olfactory receptors (ORs) to their ligands a daunting task. Krautwurst and colleagues have hypothesized that this...
The vast number of detectable odors makes matching olfactory receptors (ORs) to their ligands a daunting task. Krautwurst and colleagues have hypothesized that this process can be simplified by focusing on those odorants that are perceptually relevant food odors. In this issue of Chemical Senses, they use this framework to identify highly sensitive receptors for 2 key food odorants found in red wine and onions, that activate broadly tuned OR1A1 and narrowly tuned OR2M3, respectively. This work provides further evidence for the advantage of screening receptors against ecologically relevant odors, and we discuss it in the context of current limitations in OR screening methods.
Topics: Food; Ligands; Odorants; Olfactory Receptor Neurons; Receptors, Odorant; Smell
PubMed: 28200040
DOI: 10.1093/chemse/bjx002 -
Philosophical Transactions of the Royal... Jun 2020Although anthropologists frequently report the centrality of odours in the daily lives and cultural beliefs of many small-scale communities, Western scholars have...
Although anthropologists frequently report the centrality of odours in the daily lives and cultural beliefs of many small-scale communities, Western scholars have historically considered the sense of smell as minimally involved in human communication. Here, we suggest that the origin and persistence of this latter view might be a consequence of the fact that most research is conducted on participants from Western societies who, collectively, were rather (adults), and (ODD) to various aspects of olfactory perception. The view is rapidly changing, however, and this themed issue provides a timely overview of the current state-of-the-art on human chemocommunication. Based on evolutionary models of communication, the papers cover both general mechanisms of odour production by 'senders' and odour perception by 'receivers'. Focus on specific functional contexts includes reciprocal impact of odours between infants and mothers, the role of odour in mate choice and how odours communicate emotion and disease. Finally, a position paper outlines pitfalls and opportunities for the future, against the context of the replication crisis in psychology. We believe a more nuanced view of human chemical communication is within our grasp if we can continue to develop inter-disciplinary insights and expand research activities beyond ODD people. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.
Topics: Humans; Nonverbal Communication; Odorants; Olfactory Perception
PubMed: 32306869
DOI: 10.1098/rstb.2019.0258 -
The Journal of Experimental Biology Nov 2023Motion plays an essential role in sensory acquisition. From changing the position in which information can be acquired to fine-scale probing and active sensing, animals...
Motion plays an essential role in sensory acquisition. From changing the position in which information can be acquired to fine-scale probing and active sensing, animals actively control the way they interact with the environment. In olfaction, movement impacts the time and location of odour sampling as well as the flow of odour molecules around the olfactory organs. Employing a detailed spatiotemporal analysis, we investigated how insect antennae interact with the olfactory environment in a species with a well-studied olfactory system - the American cockroach. Cockroaches were tested in a wind-tunnel setup during the presentation of odours with different attractivity levels: colony extract, butanol and linalool. Our analysis revealed significant changes in antennal kinematics when odours were presented, including a shift towards the stream position, an increase in vertical movement and high-frequency local oscillations. Nevertheless, the antennal shifting occurred predominantly in a single antenna while the overall range covered by both antennae was maintained throughout. These findings hold true for both static and moving stimuli and were more pronounced for attractive odours. Furthermore, we found that upon odour encounter, there was an increase in the occurrence of high-frequency antennal sweeps and vertical strokes, which were shown to impact the olfactory environment's statistics directly. Our study lays out a tractable system for exploring the tight coupling between sensing and movement, in which antennal sweeps, in parallel to mammalian sniffing, are actively involved in facilitating odour capture and transport, generating odour intermittency in environments with low air movement where cockroaches dwell.
Topics: Animals; Smell; Periplaneta; Odorants; Cockroaches; Sense Organs; Arthropod Antennae; Mammals
PubMed: 37750327
DOI: 10.1242/jeb.245337 -
Brain Research Feb 2020Most odors are not composed of a single volatile chemical species, but rather are mixtures of many different volatile molecules, the perception of which is dependent on...
Most odors are not composed of a single volatile chemical species, but rather are mixtures of many different volatile molecules, the perception of which is dependent on the identity and relative concentrations of the components. Changing either the identity or ratio of components can lead to shifts between configural and elemental perception of the mixture. For example, a 30/70 ratio of ethyl isobutyrate (odorant A, a strawberry scent) and ethyl maltol (odorant B, a caramel scent) is perceived as pineapple by humans - a configural percept distinct from the components. In contrast, a 68/32 ratio of the same odorants is perceived elementally, and is identified as the component odors. Here, we examined single-unit responses in the anterior and posterior piriform cortex (aPCX and pPCX) of mice to these A and B mixtures. We first demonstrate that mouse behavior is consistent with a configural/elemental perceptual shift as concentration ratio varies. We then compared responses to the configural mixture to those evoked by the elemental mixture, as well as to the individual components. Hierarchical cluster analyses suggest that in the mouse aPCX, the configural mixture was coded as distinct from both components, while the elemental mixture was coded as similar to the components. In contrast, mixture perception did not predict pPCX ensemble coding. Similar electrophysiological results were also observed in rats. The results suggest similar perceptual characteristics of the AB mixture across species, and a division in the roles of aPCX and pPCX in the coding of configural and elemental odor mixtures.
Topics: Animals; Female; Male; Mice; Odorants; Olfactory Perception; Piriform Cortex; Rats; Rats, Long-Evans
PubMed: 31866364
DOI: 10.1016/j.brainres.2019.146617 -
Current Biology : CB Jul 2021Odor perception in non-humans is poorly understood. Here, we generated the most comprehensive mouse olfactory ethological atlas to date, consisting of behavioral...
Odor perception in non-humans is poorly understood. Here, we generated the most comprehensive mouse olfactory ethological atlas to date, consisting of behavioral responses to a diverse panel of 73 odorants, including 12 at multiple concentrations. These data revealed that mouse behavior is incredibly diverse and changes in response to odorant identity and concentration. Using only behavioral responses observed in other mice, we could predict which of two odorants was presented to a held-out mouse 82% of the time. Considering all 73 possible odorants, we could uniquely identify the target odorant from behavior on the first try 20% of the time and 46% within five attempts. Although mouse behavior is difficult to predict from human perception, they share three fundamental properties: first, odor valence parameters explained the highest variance of olfactory perception. Second, physicochemical properties of odorants can be used to predict the olfactory percept. Third, odorant concentration quantitatively and qualitatively impacts olfactory perception. These results increase our understanding of mouse olfactory behavior and how it compares to human odor perception and provide a template for future comparative studies of olfactory percepts among species.
Topics: Animals; Ascomycota; Mice; Odorants; Olfactory Perception; Smell
PubMed: 33957076
DOI: 10.1016/j.cub.2021.04.020 -
BMC Microbiology Apr 2022Some people produce specific body odours that make them more attractive than others to mosquitoes, and consequently are at higher risk of contracting vector-borne...
BACKGROUND
Some people produce specific body odours that make them more attractive than others to mosquitoes, and consequently are at higher risk of contracting vector-borne diseases. The skin microbiome can break down carbohydrates, fatty acids and peptides on the skin into volatiles that mosquitoes can differentiate.
RESULTS
Here, we examined how skin microbiome composition of women differs in relation to level of attractiveness to Anopheles coluzzii mosquitoes, to identify volatiles in body odour and metabolic pathways associated with individuals that tend to be poorly-attractive to mosquitoes. We used behavioural assays to measure attractiveness of participants to An. coluzzii mosquitoes, 16S rRNA amplicon sequencing of the bacteria sampled from the skin and gas chromatography of volatiles in body odour. We found differences in skin microbiome composition between the poorly- and highly-attractive groups, particularly eight Amplicon Sequence Variants (ASVs) belonging to the Proteobacteria, Actinobacteria and Firmicutes phyla. Staphylococcus 2 ASVs are four times as abundant in the highly-attractive compared to poorly-attractive group. Associations were found between these ASVs and volatiles known to be attractive to Anopheles mosquitoes. Propanoic pathways are enriched in the poorly-attractive participants compared to those found to be highly-attractive.
CONCLUSIONS
Our findings suggest that variation in attractiveness of people to mosquitoes is related to the composition of the skin microbiota, knowledge that could improve odour-baited traps or other next generation vector control tools.
Topics: Animals; Anopheles; Bacteria; Female; Humans; Microbiota; Mosquito Vectors; Odorants; RNA, Ribosomal, 16S
PubMed: 35410125
DOI: 10.1186/s12866-022-02502-4 -
The Journal of Experimental Biology Mar 2022Animals, including humans, detect odours and use this information to behave efficiently in the environment. Frequently, odours consist of complex mixtures of odorants...
Animals, including humans, detect odours and use this information to behave efficiently in the environment. Frequently, odours consist of complex mixtures of odorants rather than single odorants, and mixtures are often perceived as configural wholes, i.e. as odour objects (e.g. food, partners). The biological rules governing this 'configural perception' (as opposed to the elemental perception of mixtures through their components) remain weakly understood. Here, we first review examples of configural mixture processing in diverse species involving species-specific biological signals. Then, we present the original hypothesis that at least certain mixtures can be processed configurally across species. Indeed, experiments conducted in human adults, newborn rabbits and, more recently, in rodents and honeybees show that these species process some mixtures in a remarkably similar fashion. Strikingly, a mixture AB (A, ethyl isobutyrate; B, ethyl maltol) induces configural processing in humans, who perceive a mixture odour quality (pineapple) distinct from the component qualities (A, strawberry; B, caramel). The same mixture is weakly configurally processed in rabbit neonates, which perceive a particular odour for the mixture in addition to the component odours. Mice and honeybees also perceive the AB mixture configurally, as they respond differently to the mixture compared with its components. Based on these results and others, including neurophysiological approaches, we propose that certain mixtures are convergently perceived across various species of vertebrates/invertebrates, possibly as a result of a similar anatomical organization of their olfactory systems and the common necessity to simplify the environment's chemical complexity in order to display adaptive behaviours.
Topics: Animals; Animals, Newborn; Mice; Odorants; Olfactory Perception; Rabbits; Rodentia; Smell; Species Specificity
PubMed: 35285471
DOI: 10.1242/jeb.242274 -
Scientific Reports Jan 2017Habituation is a filter that optimizes the processing of information by our brain in all sensory modalities. It results in an unconscious reduced responsiveness to...
Habituation is a filter that optimizes the processing of information by our brain in all sensory modalities. It results in an unconscious reduced responsiveness to continuous or repetitive stimulation. In olfaction, the main question is whether habituation works the same way for any odorant or whether we habituate differently to each odorant? In particular, whether chemical, physical or perceptual cues can limit or increase habituation. To test this, the odour intensity of 32 odorants differing in physicochemical characteristics was rated by 58 participants continuously during 120s. Each odorant was delivered at a constant concentration. Results showed odorants differed significantly in habituation, highlighting the multifactoriality of habituation. Additionally habituation was predicted from 15 physico-chemical and perceptual characteristics of the odorants. The analysis highlighted the importance of trigeminality which is highly correlated to intensity and pleasantness. The vapour pressure, the molecular weight, the Odor Activity Value (OAV) and the number of double bonds mostly contributed to the modulation of habituation. Moreover, length of the carbon chain, number of conformers and hydrophobicity contributed to a lesser extent to the modulation of habituation. These results highlight new principles involved in the fundamental process of habituation, notably trigeminality and the physicochemical characteristics associated.
Topics: Adult; Chemical Phenomena; Female; Habituation, Psychophysiologic; Humans; Male; Odorants; Smell; Young Adult
PubMed: 28120877
DOI: 10.1038/srep41047 -
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