Electrochemical Modulation of Odorant Molecule: A Study of p-cresol

In color vision, the quantitative rules for mixing lights to make a target color are well understood. By contrast, the rules for mixing odorants to make a target odor remain elusive. A solution to this problem in vision relied on characterizing receptor responses to different wavelengths of light and subsequently relating these responses to perception. In olfaction, experimentally measuring receptor responses to a representative set of complex mixtures is intractable due to the vast number of possibilities. To meet this challenge, we develop a biophysical model that predicts mammalian receptor responses to complex mixtures using responses to single odorants. The dominant nonlinearity in our model is competitive binding (CB): Only one odorant molecule can attach to a receptor binding site at a time. This simple framework predicts receptor responses to mixtures of up to 12 monomolecular odorants to within 15% of experimental observations and provides a powerful method for leveraging limited experimental data. Simple extensions of our model describe phenomena such as synergy, overshadowing, and inhibition. We demonstrate that the presence of such interactions can be identified via systematic deviations from the competitive-binding model.

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Exploring the Mechanism of Olfactory Recognition at the Initial Stage by Modeling the Emission Spectrum of Electron Transfer

10.1101/641738 ◽

2019 ◽

Author(s):

Shu Liu ◽

Rao Fu ◽

Guangwu Li

Keyword(s):

Electron Transfer ◽

Emission Spectrum ◽

Active Sites ◽

Isotope Effects ◽

Emission Spectra ◽

Initial Stage ◽

Olfactory Sense ◽

Bitter Almond ◽

Deuterated Analogue ◽

Odorant Molecule

AbstractOlfactory sense remains elusive regarding the primary reception mechanism. Some studies suggest that olfaction is a spectral sense, the olfactory event is triggered by electron transfer (ET) across the odorants at the active sites of odorant receptors (ORs). Herein we present a Donor-Bridge-Acceptor model, proposing that the ET process can be viewed as an electron hopping from the donor molecule to the odorant molecule (Bridge), then hopping off to the acceptor molecule, making the electronic state of the odorant molecule change along with vibrations (vibronic transition). The odorant specific parameter, Huang–Rhys factor can be derived from ab initio calculations, which make the simulation of ET spectra achievable. In this study, we revealed that the emission spectra (after Gaussian convolution) can be acted as odor characteristic spectra. Using the emission spectrum of ET, we were able to reasonably interpret the similar bitter-almond odors among hydrogen cyanide, benzaldehyde and nitrobenzene. In terms of isotope effects, we succeeded in explaining why subjects can easily distinguish cyclopentadecanone from its fully deuterated analogue cyclopentadecanone-d28 but not distinguishing acetophenone from acetophenone-d8.

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Studies of the Impact of Hydrogen on the Stability of Gaseous Mixtures of THT

Energies ◽

10.3390/en13236441 ◽

2020 ◽

Vol 13 (23) ◽

pp. 6441

Author(s):

Anna Huszal ◽

Jacek Jaworski

Keyword(s):

Natural Gas ◽

Distribution Network ◽

Experimental Tests ◽

Gaseous Mixtures ◽

Odorant Molecule ◽

Measurement Devices ◽

The Stability ◽

The Impact ◽

Hydrogen Additive

One of the most important requirements concerning the quality of natural gases, guaranteeing their safe use, involves providing the proper level of their odorization. This allows for the detection of uncontrolled leakages of gases from gas networks, installations and devices. The concentration of an odorant should be adjusted in such a manner that the gas odor in a mixture with air would be noticeable by users (gas receivers). A permanent odor of gas is guaranteed by the stability of the odorant molecule and its resistance to changes in the composition of odorized gases. The article presents the results of experimental research on the impact of a hydrogen additive on the stability of tetrahydrothiophene (THT) mixtures in methane and in natural gas with a hydrogen additive. The objective of the work was to determine the readiness of measurement infrastructures routinely used in monitoring the process of odorizing natural gas for potential changes in its composition. One of the elements of this infrastructure includes the reference mixtures of THT, used to verify the correctness of the readings of measurement devices. The performed experimental tests address possible changes in the composition of gases supplied via a distribution network, resulting from the introduction of hydrogen. The lack of interaction between hydrogen and THT has been verified indirectly by assessing the stability of its mixtures with methane and natural gas containing hydrogen. The results of the presented tests permitted the identification of potential hazards for the safe use of gas from a distribution network, resulting from changes in its composition caused by the addition of hydrogen.

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Vibration-based biomimetic odor classification

Scientific Reports ◽

10.1038/s41598-021-90592-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nidhi Pandey ◽

Debasattam Pal ◽

Dipankar Saha ◽

Swaroop Ganguly

Keyword(s):

Spectral Clustering ◽

Atomistic Simulations ◽

Vibrational Modes ◽

Shape Theory ◽

Chemical Graph ◽

Chemical Graph Theory ◽

Eigen Value ◽

Odorant Molecule ◽

Physical Insight ◽

Odor Classification

AbstractOlfaction is not as well-understood as vision or audition, nor technologically addressed. Here, Chemical Graph Theory is shown to connect the vibrational spectrum of an odorant molecule, invoked in the Vibration Theory of Olfaction, to its structure, which is germane to the orthodox Shape Theory. Atomistic simulations yield the Eigen-VAlue (EVA) vibrational pseudo-spectra for 20 odorant molecules grouped into 6 different ‘perceptual’ classes by odour. The EVA is decomposed into peaks corresponding to different types of vibrational modes. A novel secondary pseudo-spectrum, informed by this physical insight—the Peak-Decomposed EVA (PD-EVA)—has been proposed here. Unsupervised Machine Learning (spectral clustering), applied to the PD-EVA, clusters the odours into different ‘physical’ (vibrational) classes that match the ‘perceptual’, and also reveal inherent perceptual subclasses. This establishes a physical basis for vibration-based odour classification, harmonizes the Shape and Vibration theories, and points to vibration-based sensing as a promising path towards a biomimetic electronic nose.

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Honeybees ( Apis mellifera ) learn to discriminate the smell of organic compounds from their respective deuterated isotopomers

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.3089 ◽

2014 ◽

Vol 281 (1778) ◽

pp. 20133089 ◽

Cited By ~ 13

Author(s):

Wulfila Gronenberg ◽

Ajay Raikhelkar ◽

Eric Abshire ◽

Jennifer Stevens ◽

Eric Epstein ◽

...

Keyword(s):

Apis Mellifera ◽

Receptor Protein ◽

Sensory Cells ◽

Molecular Vibrations ◽

Conditioning Paradigm ◽

Odour Discrimination ◽

Odorant Molecule ◽

Proboscis Extension ◽

Structural Aspects ◽

Primary Interaction

The understanding of physiological and molecular processes underlying the sense of smell has made considerable progress during the past three decades, revealing the cascade of molecular steps that lead to the activation of olfactory receptor (OR) neurons. However, the mode of primary interaction of odorant molecules with the OR proteins within the sensory cells is still enigmatic. Two different concepts try to explain these interactions: the ‘odotope hypothesis’ suggests that OR proteins recognize structural aspects of the odorant molecule, whereas the ‘vibration hypothesis’ proposes that intra-molecular vibrations are the basis for the recognition of the odorant by the receptor protein. The vibration hypothesis predicts that OR proteins should be able to discriminate compounds containing deuterium from their common counterparts which contain hydrogen instead of deuterium. This study tests this prediction in honeybees ( Apis mellifera ) using the proboscis extension reflex learning in a differential conditioning paradigm. Rewarding one odour (e.g. a deuterated compound) with sucrose and not rewarding the respective analogue (e.g. hydrogen-based odorant) shows that honeybees readily learn to discriminate hydrogen-based odorants from their deuterated counterparts and supports the idea that intra-molecular vibrations may contribute to odour discrimination.

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Comparison and Functional Analysis of Chemosensory Protein Genes From Eucryptorrhynchus scrobiculatus Motschulsky and Eucryptorrhynchus brandti Harold

Frontiers in Physiology ◽

10.3389/fphys.2021.661310 ◽

2021 ◽

Vol 12 ◽

Author(s):

Qian Wang ◽

Xiaojian Wen ◽

Yi Lu ◽

Junbao Wen

Keyword(s):

Host Plant ◽

Developmental Stages ◽

Niche Differentiation ◽

Binding Affinities ◽

Binding Model ◽

Chemosensory Protein ◽

Tree Of Heaven ◽

Alpha Pinene ◽

Odorant Molecule ◽

Chemosensory Systems

The tree-of-heaven root weevil (Eucryptorrhynchus scrobiculatus) and the tree-of-heaven trunk weevil (Eucryptorrhynchus brandti) are closely related species that monophagously feed on the same host plant, the Ailanthus altissima (Mill) Swingle, at different locations. However, the mechanisms of how they select different parts of the host tree are unclear. As chemosensory systems play important roles in host location and oviposition, we screened candidate chemosensory protein genes from the transcriptomes of the two weevils at different developmental stages. In this study, we identified 12 candidate chemosensory proteins (CSPs) of E. scrobiculatus and E. brandti, three EscrCSPs, and one EbraCSPs, respectively, were newly identified. The qRT-PCR results showed that EscrCSP7/8a/9 and EbraCSP7/8/9 were significantly expressed in adult antennae, while EscrCSP8a and EbraCSP8 shared low sequence identity, suggesting that they may respond to different odorant molecule binding. Additionally, EbraCSP6 and EscrCSP6 were mainly expressed in antennae and proboscises and likely participate in the process of chemoreception. The binding simulation of nine volatile compounds of the host plant to EscrCSP8a and EbraCSP8 indicated that (1R)-(+)-alpha-pinene, (–)-beta-caryophyllene, and beta-elemen have higher binding affinities with EscrCSP8a and lower affinities with EbraCSP8. In addition, there were seven, two, and one EbraCSPs mainly expressed in pupae, larvae, and eggs, respectively, indicating possible developmental-related roles in E. brandti. We screened out several olfactory-related possible CSP genes in E. brandti and E. scrobiculatus and simulated the binding model of CSPs with different compounds, providing a basis for explaining the niche differentiation of the two weevils.

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A competitive binding model predicts nonlinear responses of olfactory receptors to complex mixtures

10.1101/311514 ◽

2018 ◽

Cited By ~ 3

Author(s):

Vijay Singh ◽

Nicolle R. Murphy ◽

Vijay Balasubramanian ◽

Joel D. Mainland

Keyword(s):

Olfactory Receptors ◽

Competitive Binding ◽

Complex Mixtures ◽

Biophysical Model ◽

Target Color ◽

Receptor Binding Site ◽

Binding Model ◽

Vast Number ◽

Nonlinear Responses ◽

Odorant Molecule

In color vision, the quantitative rules for mixing lights to make a target color are well understood. By contrast, the rules for mixing odorants to make a target odor remain elusive. A solution to this problem in vision relied on characterizing receptor responses to different wavelengths of light and subsequently relating these responses to perception. In olfaction, experimentally measuring receptor responses to a representative set of complex mixtures is intractable due to the vast number of possibilities. To meet this challenge, we develop a biophysical model that predicts mammalian receptor responses to complex mixtures using responses to single odorants. The dominant nonlinearity in our model is competitive binding (CB): only one odorant molecule can attach to a receptor binding site at a time. This simple framework predicts receptor responses to mixtures of up to twelve monomolecular odorants to within 15% of experimental observations and provides a powerful method for leveraging limited experimental data. Simple extensions of our model describe phenomena such as synergy, overshadowing, and inhibition. We demonstrate that the presence of such interactions can be identified via systematic deviations from the competitive binding model.

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African Gene Flow Reduces Beta-Ionone Anosmia/Hyposmia Prevalence in Admixed Malagasy Populations

Brain Sciences ◽

10.3390/brainsci11111405 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1405

Author(s):

Harilanto Razafindrazaka ◽

Veronica Pereda-Loth ◽

Camille Ferdenzi ◽

Margit Heiske ◽

Omar Alva ◽

...

Keyword(s):

Gene Flow ◽

African Ancestry ◽

Sensory Perception ◽

Population Level ◽

P Value ◽

Individual Level ◽

Specific Anosmia ◽

Odorant Molecule ◽

The Individual ◽

The Impact

While recent advances in genetics make it possible to follow the genetic exchanges between populations and their phenotypic consequences, the impact of the genetic exchanges on the sensory perception of populations has yet to be explored. From this perspective, the present study investigated the consequences of African gene flow on odor perception in a Malagasy population with a predominantly East Asian genetic background. To this end, we combined psychophysical tests with genotype data of 235 individuals who were asked to smell the odorant molecule beta-ionone (βI). Results showed that in this population the ancestry of the OR5A1 gene significantly influences the ability to detect βI. At the individual level, African ancestry significantly protects against specific anosmia/hyposmia due to the higher frequency of the functional gene (OR ratios = 14, CI: 1.8–110, p-value = 0.012). At the population level, African introgression decreased the prevalence of specific anosmia/hyposmia to this odorous compound. Taken together, these findings validate the conjecture that in addition to cultural exchanges, genetic transfer may also influence the sensory perception of the population in contact.

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Linalool: a review on a key odorant molecule with valuable biological properties

Flavour and Fragrance Journal ◽

10.1002/ffj.3197 ◽

2014 ◽

Vol 29 (4) ◽

pp. 193-219 ◽

Cited By ~ 97

Author(s):

Ana Clara Aprotosoaie ◽

Monica Hăncianu ◽

Irina-Iuliana Costache ◽

Anca Miron

Keyword(s):

Biological Properties ◽

Odorant Molecule

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