Human Odor Research Articles

Human body odour as a biometric indicator for person identification

In biometric identification, various physiological and behavioral traits such as fingerprints, facial features, iris patterns, and voice have been extensively explored. This paper introduces human body odour as a biometric trait for person identification. Body odour, composed of volatile organic compounds unique to each individual, presents a challenge for biometric authentication. The study explores the scientific basis of human body odour, including its chemical composition and uniqueness. The paper presents the enrollment process for capturing and storing body odour data, emphasizing the potential of electronic nose (E-nose) devices for scent detection and pattern recognition. This paper discusses the advantages of body odour biometrics, including its resistance to masking by artificial scents and its potential to reduce password administration costs. The proposed odour biometric system offers a non-intrusive and reliable means of person identification, particularly in scenarios where traditional biometric modalities may be impractical or ineffective.

Genetic variation in the human olfactory receptor OR5AN1 associates with the perception of musks.

Humans have significant individual variations in odor perception, derived from their experience or sometimes from differences in the olfactory receptor (OR) gene repertoire. In several cases, the genetic variation of a single OR affects the perception of its cognate odor ligand. Musks are widely used for fragrance and are known to demonstrate specific anosmia. It, however, remains to be elucidated whether the OR polymorphism contributes to individual variations in musk odor perception. Previous studies reported that responses of the human musk receptor OR5AN1 to a variety of musks in vitro correlated well with perceptual sensitivity to those odors in humans and that the mouse ortholog, Olfr1440 (MOR215-1), plays a critical role in muscone perception. Here, we took advantage of genetic variation in OR5AN1 to examine how changes in receptor sensitivity are associated with human musk perception. We investigated the functional differences between OR5AN1 variants in an in vitro assay and measured both perceived intensity and detection threshold in human subjects with different OR5AN1 genotypes. Human subjects homozygous for the more sensitive L289F allele had a lower detection threshold for muscone and found macrocyclic musks to be more intense than subjects homozygous for the reference allele. These results demonstrate that the genetic variation in OR5AN1 contributes to perceptual differences for some musks. In addition, we found that the more functional variant of OR5A1, a receptor involved in β-ionone perception, is associated with the less functional variant of OR5AN1, suggesting that the perceived intensities of macrocyclic musks and β-ionone are inversely correlated.

A mobile APP-based, customizable automated device for self-administered olfactory testing and an implementation of smell identification test.

Olfactory tests are used for the evaluation of ability to detect and identify common odors in humans psychophysically. Olfactory tests are currently administered by professionals with a set of given odorants. Manual administration of such tests can be labor and cost intensive and data collected as such are confounded with experimental variables, which adds personnel costs and introduces potential errors and data variability. For large-scale and longitudinal studies, manually recorded data must be collected and compiled from multiple sites. It is difficult to standardize the way data are collected and recorded. There is a need for a computerized smell test system for psychophysical and clinical applications. A mobile digital olfactory testing system (DOTS) was developed, consisting of an odor delivery system (DOTS-ODD) and a mobile application program (DOTS-APP) connected wirelessly. The University of Pennsylvania Smell Identification Test was implemented in DOTS and compared to its commercial product on a cohort of 80 normosmic subjects and a clinical cohort of 12 Parkinson's disease patients. A test-retest was conducted on 29 subjects of the normal cohort. The smell identification scores obtained from the DOTS and standard UPSIT commercial test are highly correlated (r = 0.714, P < 0.001), and test-retest reliability coefficient was 0.807 (r = 0.807, P < 0.001). The DOTS is customizable and mobile compatible, which allows for the implementation of standardized olfactory tests and the customization of investigators' experimental paradigms. The DOTS-APP on mobile devices offers capabilities for a broad range of on-site, online, or remote clinical and scientific chemosensory applications.

Специфіка кінематографічного втілення мотиву фаустіанства за романом П. Зюскінда «Парфуми. Історія одного вбивці»

The purpose of the article is to determine the peculiarities of the implementation of the Faustian motif in the film version of P. Süskind's novel «Perfume: The Story of a Murderer» (2006) and the remake – the TV series «Perfume (Parfum)» (2018), both based on the novel by Süskind. The objective of the research is to compare the implementation of genre features, the image of the main character, and the motivation of his and other characters’ actions in the film and the TV series, to analyze the use of artistic techniques in the literary adaptation. The objectives of the research were achieved via the employment of comparative and analytical methods, which facilitated establishing the peculiarities of the intermedial transformation of P. Süskind’s novel and analysis of the metamodernist manifestations in the cinematic versions of the novel. In the context of Faustianism, the proposed study of the film adaptation of Süskind's novel is carried out for the first time. It has been established that Tom Tykwer's film is dominated by elements of the genres of romantic detective and thriller, while in the series the elements of detective and erotic thriller prevail. Elements of other genres can also be recognized in the film, except for philosophical and educational. It is established that the task of rendering the smell the creators of the film solve through the use of artistic means – the props, non-verbal signs, musical accompaniment, and visual effects. It is revealed that the main problem faced by the creators of the film was the creation of a positive image of the main character, a marginalized person rejected by society. Tom Tykwer's team created the image of an attractive criminal, a lone genius who invented the perfect perfume at the cost of crime. In the film, the main motif of Faustianism is successfully implemented – the desire for knowledge, as for the other Faustian motifs – the connection with mystical forces, and the desire for beauty – they are painted sporadically. The film also does not show the main character’s attitude to God, to the concepts of good and evil. The plot of the «Perfume» series (2018) is based on the murder of the red-haired singer Katharina Läufer; memories and experiences of her friends from the Catholic boarding school, who were once impressed by Patrick Süskind's novel «Perfume: The Story of a Murderer», which inspired them to experiment with human odors, searching for the perfect fragrance. The creators of the series raised the question to the audience: is it possible to manipulate people with the help of smells? At the center of the plot are six teenagers and then later five friends of the singer Katharina Läufer, and three detectives. Grenouille's image from the novel is split into several protagonists. The main motive that determines their actions is the desire for love. In the novel «Perfume: The Story of a Murderer» the author manages to maintain the attention of the readers through his virtuoso mastery of style, whereas in the film and TV series, the emphasis is on feelings. The language of sensuality, widely used in Tom Tykwer's film, is one of the hallmarks of metamodernism. The «Perfume» series (2018), where the characters are in constant search, they worry and strive to become better, we consider to be a typical cultural product of the metamodernism era. The audience's perception of the film and the series, in contrast to the unfavorable attitude of critics and journalists, indicates the birth of a new socio-cultural reality and its influence on the work of filmmakers and writers. Keywords: Faustian, motive, micro-image of the smell, postmodernism, metamodernism, Patrick Süskind, Tom Tykwer.

Structure modelling of odorant receptor from Aedes aegypti and identification of potential repellent molecules

Odorant receptors (ORs) are important class of proteins involved in olfactory behaviour of insects. These are GPCR-like heptahelical transmembrane proteins with inverted topology compared to GPCR and require a co-receptor (ORco) for their function. OR function can be modulated through small molecules and negative modulation can be beneficial in case of disease vectors like Aedes aegypti. OR4 of A. aegypti is implicated in host recognition through human odour. Aedes aegypti is a vector for viruses that spread diseases like dengue, Zika and Chikungunya. In this study, we have attempted to model the full-length structure of OR4 and the ORco of A. aegypti due to lack of experimental structure. Further, we have screened a library of natural compounds (>0.3 million) along with known repellent molecules against ORco and OR4. Many natural compounds, including those from plants like Ocimum tenuiflorum (Holy Basil) and Piper nigrum (Black pepper), were found to have better binding affinity towards ORco compared to known repellents like DEET providing an alternative to existing repellent molecules. For specific inhibitor of OR4, several natural compounds (including those from plant like Mulberry) were identified. Further, we have utilized multiple docking approaches and conservation analysis to understand the interaction between OR4 and ORco. It was observed that the residues from the seventh transmembrane helix of OR4 and pore forming helix of ORco could play an important role along with known intracellular loop 3 residues in mediating the heteromer formation of OR and ORco.

Cross-modal associations of human body odour attractiveness with facial and vocal attractiveness provide little support for the backup signals hypothesis: A systematic review and meta-analysis

Cross-modal associations of human body odour attractiveness with facial and vocal attractiveness provide little support for the backup signals hypothesis: A systematic review and meta-analysis

Evolution of a Mosquito's Hatching Behavior to Match Its Human-Provided Habitat.

AbstractA subspecies of the yellow fever mosquito, Aedes aegypti, has recently evolved to specialize in biting and living alongside humans. It prefers human odor over the odor of nonhuman animals and breeds in human-provided artificial containers rather than the forest tree holes of its ancestors. Here, we report one way this human specialist has adapted to the distinct ecology of human environments. While eggs of the ancestral subspecies rarely hatch in pure water, those of the derived human specialist do so readily. We trace this novel behavior to a shift in how eggs respond to dissolved oxygen, low levels of which may signal food abundance. Moreover, we show that while tree holes are consistently low in dissolved oxygen, artificial containers often have much higher levels. There is thus a concordance between the hatching behavior of each subspecies and the aquatic habitat it uses in the wild. We find this behavioral variation is heritable, with both maternal and zygotic effects. The zygotic effect depends on dissolved oxygen concentration (i.e., a genotype-environment interaction, or G×E), pointing to potential changes in oxygen-sensitive circuits. Together, our results suggest that a shift in hatching response contributed to the pernicious success of this human-specialist mosquito and illustrate how animals may rapidly adapt to human-driven changes in the environment.

Chemosensory detection of aversive concentrations of ammonia and basic volatile amines in insects

Basic volatiles like ammonia are found in insect environments, and at high concentrations cause an atypical action potential burst, followed by inhibition in multiple classes of olfactory receptor neurons (ORNs) in Drosophila melanogaster. During the period of inhibition, ORNs are unable to fire action potentials to their ligands but continue to display receptor potentials. An increase in calcium is also observed in antennal cells of Drosophila and Aedes aegypti. In the gustatory system, ammonia inhibits sugar and salt responses in a dose-dependent manner. Other amines show similar effects in both gustatory and olfactory neurons, correlated with basicity. The concentrations that inhibit neurons reduce proboscis extension to sucrose in Drosophila. In Aedes, a brief exposure to volatile ammonia abolishes attraction to human skin odor for several minutes. These findings reveal an effect that prevents detection of attractive ligands in the olfactory and gustatory systems and has potential in insect control.

Axillary fossaa microbial dysbiosis and its relationship with axillary osmidrosis patients

BackgroundSkin is one of the largest human bacterial reservoirs, especially the human axilla. The microbiota of the human axilla plays an important role in the creation of axillary smell. AimsTo explore the structure and composition of the axillary fossa microbiota between bromhidrosis patients and normal people, skin samples were collected from the armpits of 40 individuals, including 20 patients (10 males (aM), 10 females (aF), osmidrosis), and 20 healthy individuals (10 males (NM), 10 females (NF), control). MethodsHigh-throughput sequencing of the 16S rRNA gene was carried out on a Hiseq2500 platform with the V3+V4 regions. ResultsAccording to the bacterial Shannon diversity index and Simpson, we found that aF was significantly higher than the control but aM had no obvious distinction. Actinobacteria, Firmicutes, Proteobacteria and Deinococcus-Thermus were the dominant phyla in the four groups. Actinobacteria was distinctly higher in aM, while Firmicutes was significantly lower in aM. Furthermore, the aF displayed inverse results with aM. Corynebacterium-1 and Staphylococcus were the dominant genera in the four groups. Interestingly, Staphylococcus was the most abundant in aF, and Corynebacterium-1 was the dominant genus in aM and Corynebacterium-kroppenstedtii was significantly different in aM. Moreover, functional capacity analysis showed that genes associated with amino acid metabolism and lipid metabolism were higher in aM than in other groups, while pyruvate metabolism (carbohydrate metabolism) was obviously high in aF. ConclusionThere were clearly distinct of axillary microbiota undergoes changes between bromhidrosis patients and controls. Staphylococcus and Corynebacterium-1 in aF and aM, respectively, were detected with distinctly elevated proportions, which might be strongly related to human axilla odor.

Mosquito host-seeking diel rhythm and chemosensory gene expression is affected by age and Plasmodium stages

Malaria parasites can affect vector-related behaviours, increasing transmission success. Using Anopheles gambiae and Plasmodium falciparum, we consider the effect of interaction between infection stage and vector age on diel locomotion in response to human odour and the expression of antennal chemosensory genes. We identified age-dependent behavioural diel compartmentalisation by uninfected females post-blood meal. Infection disrupts overall and diel activity patterns compared with age-matched controls. In this study, mosquitoes carrying transmissible sporozoites were more active, shifting activity periods which corresponded with human host availability, in response to human odour. Older, uninfected, blood-fed females displayed reduced activity during their peak host-seeking period in response to human odour. Age- and infection stage-specific changes in odour-mediated locomotion coincide with altered transcript abundance of select chemosensory genes suggesting a possible molecular mechanism regulating the behaviour. We hypothesize that vector-related behaviours of female mosquitoes are altered by infection stage and further modulated by the age post-blood meal of the vector. Findings may have important implications for malaria transmission and disease dynamics.

Mosquito-borne pathogens hijack human body odors to promote transmission.

Mosquito-borne pathogens hijack human body odors to promote transmission.

L-lactic and 2-ketoglutaric Acids, Odors from Human Skin, Govern Attraction and Landing in Host-Seeking Female Aedes aegypti Mosquitoes

Aedes aegypti, presented with a source of L-lactic and 2-ketoglutaric acid in a wind-tunnel bioassay, takeoff, fly upwind, and land on the odorant substrate at rates comparable to those exhibited by mosquitoes presented with a skin-odor stimulus. Addition of carbon dioxide decreased takeoff latency but was not required to elicit upwind flight nor landings. Ketoglutaric acid, a recently identified component of human skin odor, combined with lactic acid elicits the full repertoire of mosquito host-seeking behaviors.

A new approach to signal filtering method using K-means clustering and distance-based Kalman filtering

Human axillary odours taken by an electronic nose (e-nose) device that uses a Metal Oxide Semiconductor (MOS) sensor not only contains a gas signal from the pure source of the axillary odour but also has the potential to contain other substances such as perfume and deodorant. This situation requires noise reduction so that dirty data can be cleaned and produce better predictions without wasting a lot of data. The approach taken in this study is to detect data clusters and data centroids from each reference data. Dimensional reduction using Linear Discriminant Analysis (LDA) on the reference data is carried out, then look for the centroid of each data using K-Means Clustering and use it to be a good signal estimate and process using Kalman Filtering so that it can be used to process axillary odour data containing deodorant. The proposed method was tested by a stacked Deep Neural Network (DNN) approach and can increase accuracy by 18.95% and balanced accuracy by 11.865% compared to original invalid data before filtering. The proposed method is also tested by other classification methods and able to produce the highest accuracy with 79.29% in Support Vector Classifier (SVC) and Multi-Layer Perception (MLP), while other filtering methods only get the highest accuracy with 69.03% also in SVC and MLP. We also analysed the execution time of each tested methods.

Sniff the urban park: Unveiling odor features and landscape effect on smellscape in Guangzhou, China

Smellscape, as the sense of smell cross space, has a huge impact on human behavior, attitudes and health. However, so far it has rarely been addressed and measured in both landscape practice and theories. The present case study refined the quantitative smellwalk method to examine the spatial and temporal features of urban park smellscape. The effects of landscape patterns on smellscape were further unraveled combining with remote sensing techniques and field surveys. The results indicated that: (i) human activities and nature odors dominated the urban park odor environments, (ii) the temporal variation of the urban park smellscape was mainly driven by human activities, (iii) the different site types of urban park exerted a significant impact on the composition of the smellscape, and (iv) the landscape pattern characteristics of forest, shrubs, grass, water, buildings and roads had significant effects on different types of odors. This study poses a first systematic exploration of various odors in urban green environments and offers novel insights into the design of smellscape via unveiling spatial-temporal odor distribution patterns.

Manipulation by Plasmodium Parasites of Anopheles Mosquito Behavior and Human Odors.

The phenomenon of parasites manipulating host phenotypes is well documented; the best-known examples are manipulations of host behavior. More recently, there has been interest in whether parasites can manipulate host odor phenotypes to enhance their attractiveness to vectors. We review here evidence that Plasmodium-infected mosquitoes have enhanced attraction to human hosts, especially when the parasite is sufficiently developed to be transmissible. We also review evidence suggesting that malaria-infected host odors elicit greater mosquito attraction compared to uninfected controls. We reviewed and summarized the relevant literature. Though evidence is mounting that supports both premises we reviewed, there are several confounds that complicate interpretation. These include differences in Plasmodium and mosquito species studied, stage of infection tested, age of human participants in trials, and methods used to quantify volatiles. In addition, a key requirement to support the hypothesis of manipulation by parasites is that costs of manipulation be identified, and ideally, quantified. Substantial progress has been made to unlock the importance of odor for enhancing transmission of Plasmodium. However, there needs to be more replication using similar methods to better define the odor parameters involved in this enhancement.

The human odorant receptor OR10A6 is tuned to the pheromone of the commensal fruit fly Drosophila melanogaster

SummaryAll living things speak chemistry. The challenge is to reveal the vocabulary, the odorants that enable communication across phylogenies and to translate them to physiological, behavioral, and ecological function. Olfactory receptors (ORs) interface animals with airborne odorants. Expression in heterologous cells makes it possible to interrogate single ORs and to identify cognate ligands. The cosmopolitan, anthropophilic strain of the vinegar fly Drosophila melanogaster depends on human resources and housing for survival. Curiously, humans sense the pheromone (Z)-4-undecenal (Z4-11Al) released by single fly females. A screening of all human ORs shows that the most highly expressed OR10A6 is tuned to Z4-11Al. Females of an ancestral African fly strain release a blend of Z4-11Al and Z4-9Al that produces a different aroma, which is how we distinguish these fly strains by nose. That flies and humans sense Z4-11Al via dedicated ORs shows how convergent evolution shapes communication channels between vertebrate and invertebrate animals.

Differential mosquito attraction to humans is associated with skin-derived carboxylic acid levels

Some people are more attractive to mosquitoes than others, but the mechanistic basis of this phenomenon is poorly understood. We tested mosquito attraction to human skin odor and identified people who are exceptionally attractive or unattractive to mosquitoes. These differences were stable over several years. Chemical analysis revealed that highly attractive people produce significantly more carboxylic acids in their skin emanations. Mutant mosquitoes lacking the chemosensory co-receptors Ir8a, Ir25a, or Ir76b were severely impaired in attraction to human scent, but retained the ability to differentiate highly and weakly attractive people. The link between elevated carboxylic acids in "mosquito-magnet" human skin odor and phenotypes of genetic mutations in carboxylic acid receptors suggests that such compounds contribute to differential mosquito attraction. Understanding why some humans are more attractive than others provides insights into what skin odorants are most important to the mosquito and could inform the development of more effective repellents.

Why are some people more attractive to mosquitoes than others?

Mosquitoes rely on their sense of smell to find humans to secure a blood meal, transmitting deadly diseases with their bite. In this issue of Cell, De Obaldía and colleagues examine why mosquitoes bite some people more than others and report an association with the level of carboxylic acids in the human skin odor.

Dogs can discriminate between human baseline and psychological stress condition odours.

Previous research suggests that dogs can detect when humans are experiencing stress. This study tested whether baseline and stress odours were distinguishable to dogs, using a double-blind, two-phase, three-alternative forced-choice procedure. Combined breath and sweat samples were obtained from participants at baseline, and after a stress-inducing (mental arithmetic) task. Participants’ stress was validated with self-report and physiological measures recorded via a Biopac MP150 system. Thirty-six participants’ samples were presented to four dogs across 36 sessions (16, 11, 7 and 2 sessions, respectively). Each session consisted of 10 Phase One training trials and 20 Phase Two discrimination trials. In Phase One, the dog was presented with a participant’s stress sample (taken immediately post-task) alongside two blanks (the sample materials without breath or sweat), and was required to identify the stress sample with an alert behaviour. In Phase Two, the dog was presented with the stress sample, the same participant’s baseline sample (taken pre-task), and a blank. Which sample (blank, baseline, or stress) the dog performed their alert behaviour on was measured. If dogs can correctly alert on the stress sample in Phase Two (when the baseline sample was present), it suggests that baseline and stress odours are distinguishable. Performance ranged from 90.00% to 96.88% accuracy with a combined accuracy of 93.75% (N trials = 720). A binomial test (where probability of success on a single trial was 0.33, and alpha was 0.05) showed that the proportion of correct trials was greater than that expected by chance (p < 0.001). Results indicate that the physiological processes associated with an acute psychological stress response produce changes in the volatile organic compounds emanating from breath and/or sweat that are detectable to dogs. These results add to our understanding of human-dog relationships and could have applications to Emotional Support and Post Traumatic Stress Disorder (PTSD) service dogs.

Compounds from human odor induce attraction and landing in female yellow fever mosquitoes (Aedes aegypti)

The female Aedes aegypti mosquito is a vector of many human diseases such as yellow fever, dengue, and Zika. Transmission of these viruses occurs when an infected female mosquito locates a suitable human host, alights, and blood feeds. Aedes aegypti use human-emitted odors, as well as heat and visual cues, for host location. However, none of the previously identified human-produced compounds induce significant orientation and landing on a human host. Here we show that female yellow fever mosquitoes orient to and land on a mixture of compounds identified from human skin rubbings. Using odor collection, extraction, a two-choice, bioassay-guided fractionation, and chemical analysis, we identified mixtures of 2-ketoglutaric acid and L-lactic acid as landing attractants for female Ae. aegypti. The mixture of pyruvic acid and L-lactic acid were also found to be weakly attractive. Using ratio-response assays, we found that the attraction and alighting behaviors of the mosquitoes were directly related to the ratio of these compounds presented on the surface of the glass assay beads, suggesting that these compounds could mediate landing on a human host even at sub-nanogram dosages. The newly identified compounds fill a gap in our knowledge of odor-mediated attraction of Ae. aegypti and may lead to the development of new attractant-based mosquito control tactics.