Chemical Senses

Where to lay the eggs is a crucial decision for females as it influences the success of their offspring. Female flies prefer to lay eggs on food already occupied and consumed by larvae, which facilitates social feeding, but potentially could also lead to detrimental interactions between species. Whether females can modulate their attraction to cues associated with different species is unknown. Here we analyzed the chemical profiles of eggs and larvae of 16 Drosophila species, and tested whether Drosophila flies would be attracted to larvae treated food or food with eggs from 6 different Drosophila species...

The scent of musk plays a unique role in the history of perfumery. Musk odorants comprise six diverse chemical classes and perception difference in strength and quality among human panelists have long puzzled the field of olfaction research. Three odorant receptors (OR) had recently been described for musk odorants: OR5AN1, OR1N2 and OR5A2. High functional expression of the difficult-to-express human OR5A2 was achieved by a modification of the C-terminal domain and the link between sensory perception and receptor activation for the trilogy of these receptors and their key genetic variants was investigated: All three receptors detect only musky smelling compounds among 440 commercial fragrance compounds...

Astringency is an important mouthfeel attribute that influences the sensory experiences of many food and beverage products. While salivary lubricity loss and increased oral friction were previously believed to be the only astringency mechanisms, recent research has demonstrated that non-tactile oral receptors can trigger astringency by responding to astringents without mechanical stimulation. Various human factors have also been identified that affect individual responses to astringents. This article presents a critical review of the key research milestones contributing to the current understanding of astringency mechanisms and the instrumental approaches used to quantify perceived astringency intensity...

Oral tactile sensitivity underpins food texture perception, but few studies have investigated mechanoreception in oral tissues. During food consumption, oral tissues are exposed to a wide range of temperatures and chemical entities. The objective of the present study was to assess the influence of thermal sensations on lingual roughness sensitivity. Just-noticeable difference thresholds (JNDs) were determined using the staircase method for surface roughness from stainless steel coupons (Ra; 0.177-0.465 µm)...

The sense of smell allows for the assessment of the chemical composition of volatiles in our environment. Different factors are associated with reduced olfactory function, including age, sex, as well as health and lifestyle conditions. However, most studies that aimed at identifying the variables that drive olfactory function in the population suffered from methodological weaknesses differences in study designs and participant selection, such as the inclusion of convenience sample or only of certain age groups, or recruitment biases...

Different animals have distinctive anatomical and physiological properties to their chemical senses that enhance detection and discrimination of relevant chemical cues. Humans and other vertebrates are recognized as having two main chemical senses, olfaction and gustation, distinguished from each other by their evolutionarily conserved neuroanatomical organization. This distinction between olfaction and gustation in vertebrates is not based on the medium in which they live because the most ancestral and numerous vertebrates, the fishes, live in an aquatic habitat and thus both olfaction and gustation occur in water and both can be of high sensitivity...

Many common chemotherapeutics produce disruptions in the sense of taste which can lead to loss of appetite, nutritional imbalance, and reduced quality of life, especially if taste loss persists after treatment ends. Cyclophosphamide (CYP), an alkylating chemotherapeutic agent, affects taste sensitivity through its cytotoxic effects on mature taste receptor cells (TRCs) and on taste progenitor cell populations, retarding the capacity to replace TRCs. Mechanistic studies have focused primarily on taste cells, however, taste signaling requires communication between TRCs and the gustatory nerve fibers which innervate them...

Clinical assessment of an individual's sense of smell has gained prominence, but its resource-intensive nature necessitates the exploration of self-administered methods. In this study, a cohort of 68 patients with olfactory loss and 55 controls were assessed using a recently introduced olfactory test. This test involves sorting two odorants (eugenol, phenylethyl alcohol) in five dilutions according to odor intensity, with an average application time of 3.5 minutes. The sorting task score, calculated as the mean of Kendall's Tau between the assigned and true dilution orders and normalized to [0,1], identified a cutoff for anosmia at a score ≤ 0...

Many volatile organic compounds (VOCs) are used to produce various commercial products with aromas mimicking natural products. The VOCs responsible for aromas have been identified from many natural products. The current major strategy is to analyze chemical compositions and aroma qualities of individual VOCs using gas chromatography/mass spectrometry (GC/MS) and GC-olfactometry. However, such analyses cannot determine whether candidate VOCs contribute to the characteristic aroma in mixtures of many VOCs. In this study, we developed a GC/MS-based VOC collection/omission system that can modify VOC compositions of samples easily and rapidly...

No abstract text is available yet for this article.

Olfactory elements of the human environment are essential with respect to culture, society and heritage, and robust methodological approaches are necessary to identify and describe aspects of this sensory component. To accurately investigate and advance knowledge of olfactory composition of spaces and places, that is, a smellscape - an olfactory contextualized landscape - innovative methodologies such as smellwalks can be employed as part of the research approach. Despite the increasing use of smellwalks, there is no current standard methodology for this investigative method in practice...

Chemical information in canid urine has been implicated in territoriality and influences the spacing of individuals. We identified the key volatile organic compound (VOC) components in dingo (Canis lupus dingo) urine and investigated the potential role of scents in territorial spacing. VOC analysis, using headspace gas chromatography-mass spectrometry (GC-MS), demonstrated that the information in fresh urine from adult male dingoes was sufficient to allow statistical classification into age categories. Discriminant function analyses demonstrated that the relative amounts or combinations of key VOCs from pre-prime (3-4 years), prime (5-9 years), and post-prime (≥10 years) males varied between these age categories, and that scents exposed to the environment for 4 (but not 33) days could still be classified to age categories...

In this study, the transfer of odorants, namely vanilla, and garlic, into the amniotic fluid (AF) during the second trimester was investigated by examination of collected AF samples through healthy adults. Eleven AF samples were collected from pregnant women (aged 32,9±4.9 years, 16 to 25 weeks of gestation) undergoing diagnostic amniocentesis after eating garlic oil or vanilla powder in high-fat yogurt. The control group did not receive food before amniocentesis. Two vanilla, three garlic and six control samples were collected through amniocentesis 60 to 120 minutes after ingestion...

Terrestrial mammals identify conspecifics by body odor. Dogs can also identify humans by body odor, and in some instances, humans can identify other humans by body odor as well. Despite potential for a powerful biometric tool, smell has not been systematically used for this purpose. A question arising in the application of smell to biometrics is which bodily odor source should we measure. Breath is an obvious candidate, but the associated humidity can challenge many sensing devices. The armpit is also a candidate source, but it is often doused in cosmetics...

Evidence for parental environments profoundly influencing the physiology, biology and neurobiology of future generations has been accumulating in the literature. Recent efforts to understand this phenomenon and its underlying mechanisms have sought to use species like rodents and insects to model multi-generational legacies of parental experiences like stress and nutritional exposures. From these studies, we have come to appreciate that parental exposure to salient environmental experiences impact the cadence of brain development, hormonal responses to stress, and the expression of genes that govern cellular responses to stress, in offspring...

Loss of olfactory function is a typical acute COVID-19 symptom, at least in early variants of SARS-CoV2. The time that has elapsed since the emergence of COVID-19 now allows assessing the long-term prognosis of its olfactory impact. Participants (n = 722) of whom n = 464 reported having had COVID-19 dating back with a mode of 174 days) were approached in a museum as a relatively unbiased environment. Olfactory function was diagnosed by assessing odor threshold and odor identification performance. Subjects also rated their actual olfactory function on an 11-point numerical scale [0,…10]...

The savory or umami taste of the amino acid glutamate is synergistically enhanced by the addition of the purines inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP) disodium salt. We hypothesized that the addition of purinergic ribonucleotides, along with the pyrimidine ribonucleotides, would decrease the absolute detection threshold of (increase sensitivity to) L-glutamic acid potassium salt (MPG). To test this, we measured both the absolute detection threshold of MPG alone and with a background level (3 mM) of five different 5'-ribonucleotides...

The peripheral taste system is more complex than previously thought. The novel taste-signaling proteins TRPM4 and PLCβ3 appear to function in normal taste responding as part of Type II taste cell signaling or as part of a broadly responsive taste cell that can respond to some or all classes of tastants. This work begins to disentangle the roles of intracellular components found in Type II taste cells (TRPM5, TRPM4, IP3R3) or the broadly responsive taste cells (PLCβ3, TRPM4) in driving behavioral responses to various saccharides and other sweeteners in brief access taste tests...

Although studies have shown that olfaction may contribute to the perception of tastant, literature is scarce or circumstantial, especially in humans. This study aims to (a) explore whether humans can perceive solutions of basic prototypical tastants through orthonasal and retronasal olfaction, (b) and to examine what volatile odor compounds (VOCs) underlie this ability. Solutions of five basic tastants (sucrose, sodium chloride, citric acid, monosodium glutamate (MSG), quinine dissolved in water, and two fatty acids (oleic and linoleic acid dissolved in mineral oil were prepared...

No abstract text is available yet for this article.