Chemosensory Properties Research Articles

Exposure to maternal odor enhances intake of a taste that mimicks the sensory attributes of ethanol.

Early exposure to ethanol increases subsequent acceptance of this drug. Little attention, however, has been devoted to the interaction of the taste of the drug with other, familiar or non-familiar, odors contingent with ethanol access, particularly early in ontogeny. This study assessed the influence of exposure to maternal odor on intake and grasp responses to an artificial nipple providing a solution (a sucrose-quinine mix) that emulates the taste of alcohol, in 4-day-old rat pups. The results showed that the mother's odor enhanced intake from and seeking responses to an artificial nipple that provided the solution that mimicked the taste of alcohol (Experiment 1). This pattern of results was not evoked by the odor of an unrelated dam (Experiment 2), nor was it observed when the nipple delivered water. The main new finding of the present study is that 4-day-old rats tested in the presence of the mother (and hence exposed to her odor cues) exhibited enhanced seeking and intake of a solution that mimics the chemosensory properties of ethanol.

Intensity-related distribution of sweet and bitter taste fMRI responses in the insular cortex.

The human gustatory cortex analyzes the chemosensory properties of tastants, particularly the quality, intensity, and affective valence, to determine whether a perceived substance should be ingested or rejected. Among previous studies, the spatial distribution of taste intensity-related activations within the human insula has been scarcely addressed. To spatially characterize a specialized or distributed nature of the cortical responses to taste intensities, a functional magnetic resonance imaging study was performed at 3 T in 44 healthy subjects where sweet and bitter tastants were administered at five increasing concentrations and cortex-based factorial and parametric analyses were performed. Two clusters in the right middle-posterior and left middle insula were found specialized for taste intensity processing, exhibiting a highly nonlinear profile across concentrations. Multiple clusters were found activated by sweet and bitter taste stimuli at most concentrations, in the anterior, middle-posterior, and inferior portion of the bilateral insula. Across these clusters, respectively, for the right and left insula, a superior-to-inferior and an anterior-to-posterior spatial gradient for high-to-low concentrations were observed for the most responsive intensity of both tastes. These findings may gather new insights regarding how the gustatory cortex is spatially organized during the perceptual processing of taste intensity for two basic tastants.

Magic darts and messenger molecules: Toward a phytoethnography of indigenous Amazonia

Recent scientific findings on plant intelligence are forcing anthropologists to reconsider indigenous theories of plant vitality. In this article, the authors compare original ethnographic and ethnobotanical research among two different peoples from opposite extremes of lowland South America – the Makushi of Guyana and the Matsigenka of southern Peru – and explore how somatic experiences and the chemosensory properties of plants permeate indigenous understandings of the aetiology of illness and medical efficacy in both the cosmological and microbiological domains. The authors synthesize emerging theory in ecosemiotics, embodiment, plant personhood and plant intelligence with the concept of ‘sensory ecology’ to recast multispecies ethnography as a phytochemical as well as a philosophical endeavour.

Plant RuBisCo: An Underutilized Protein for Food Applications

AbstractMalnutrition is a public health concern and chronic protein malnutrition is prevalent in early childhood in many developing countries. Plant proteins are good candidates for meeting the growing protein needs. RuBisCo (ribulose‐1,5‐bisphosphate carboxylase/oxygenase) is a photosynthetic enzyme that exists in 4 forms (I, II, III, and IV), with form I being characteristic of higher plants. Form I RuBisCo represents 50% of leaf proteins, and is, therefore, important as a source of protein for nutrition and as a functional ingredient, although the laborious extraction process for plant proteins can limit their use in food products. Column chromatography is the most effective RuBisCo purification step for laboratory research, while ultrafiltration has shown prospects for large‐scale applications. RuBisCo has excellent solubility in alkaline pH and at low denaturation temperatures. Thus, RuBisCo can form brittle gels at low concentrations, which can influence the chemosensory properties of products containing the proteins. Foaming of RuBisCo occurs around its isoelectric point, while emulsifying capacity proportionally increases with pH. Heating prior to emulsification increased the strength and stability of emulsion formed with RuBisCo. The protein is also attractive due to its high nutritional values and in vitro digestibility. Furthermore, RuBisCo is a competitive source of bioactive peptides with opioid‐like, memory‐enhancing, appetite‐stimulating, antioxidative, and antihypertensive properties, demonstrating the wide range of food applications where RuBisCo can be utilized.

Novel alanines bearing a heteroaromatic side chain: synthesis and studies on fluorescent chemosensing of metal cations with biological relevance.

A family of novel thienylbenzoxazol-5-yl-L-alanines, consisting of an alanine core bearing a benzoxazole at the side chain with a thiophene ring at position 2, substituted with different (hetero)aryl substituents, was synthesised to study the tuning of the photophysical and chemosensory properties of the resulting compounds. These novel heterocyclic alanines 3a-f and a series of structurally related bis-thienylbenzoxazolyl-alanines 3g-j were evaluated for the first time in the recognition of selected metal cations with environmental, medicinal and analytical interest such as Co2+, Cu2+, Zn2+ and Ni2+, in acetonitrile solution, with the heterocycles at the side chain acting simultaneously as the coordinating and reporting units, via fluorescence changes. This behaviour can be explained by the involvement of the electron donor heteroatoms in the recognition event, through complexation of the metal cations. The spectrofluorimetric titrations showed that thienylbenzoxazolyl-alanines 3a-j and 4a,b were non-selective fluorimetric chemosensors for the above-mentioned cations, with the best results being obtained for the interaction of Cu2+ with bis-alanine 3j and deprotected alanines 4a,b. The encouraging photophysical and metal ion sensing properties of these thienylbenzoxazolyl-alanines suggest that they can be used to obtain bioinspired fluorescent reporters for metal ion such as peptides/proteins with chemosensory/probing ability.

Metabolic Changes during Storage of Brassica napus Seeds under Moist Conditions and the Consequences for the Sensory Quality of the Resulting Virgin Oil

Virgin rapeseed (Brassica napus) oil is a valuable niche product, if delivered with a high quality. In this study, the effects of moist storage of B. napus seeds for 1 to 4 days on the seed metabolome and the chemo-sensory properties of the produced oils were determined. The concentrations of several primary metabolites, including monosaccharides and amino acids, rapidly increased in the seeds, probably indicating the breakdown of storage compounds to support seed germination. Seed concentrations of indole glucosinolates increased with a slight time offset suggesting that amino acids may be used to modify secondary metabolism. The volatile profiles of the oils were pronouncedly influenced by moist seed storage, with the sensory quality of the oils decreasing. This study provides a direct time-resolved link between seed metabolism under moist conditions and the quality of the resulting oils, thereby emphasizing the crucial role of dry seed storage in ensuring high oil quality.

Synthesis, Chemosensory Properties, and Self-Assembly of Terpyridine-Containing Conjugated Polycarbazole through RAFT Polymerization and Heck Coupling Reaction.

We report the responsive fluorescence chemosensory phenomena of a carbazole-functionalized crosslinked polymer (PCaT) with pendent terpyridine (tpy) groups as receptors of metal ions. The polymer was synthesized using Heck polymerization between 3,6-dibromide groups in a carbazole-based polymer (PC2Br) and divinyl tpy monomer. The effects of the polymeric structure on the optical and chemosensory properties of the PCaT were compared with those of a carbazole-tpy alternating conjugated polymer (PCT). Photoluminescence titrations demonstrated that the PCaT and PCT had the high sensing ability toward Fe3+ ions, with Stern–Volmer constants of 8.10 × 104 and 6.68 × 104 M−1, respectively. The limit of detection (LOD) toward Fe3+ of the PCaT and PCT was estimated to be 1.31 × 10−6 and 1.81 × 10−6 M, respectively, and the superior LOD of the PCaT was ascribed to its lowly crosslinked structure. The fluorescence of the solutions of these polymers that were quenched by Fe3+ ions recovered when trace CN− anions were added because of the high stability constant of the CN−–Fe3+ complex. Micellar aggregates with a mean diameter of approximately 239.5 nm were formed by dissolving the PCaT in tetrahydrofuran (THF) solution. Our results suggest that the PCaT is a promising material for chemosensory applications.

Brush cells, the newly identified gatekeepers of the urinary tract.

A specialized epithelial cell with chemosensory properties of taste cells known from the mouth has been newly identified in the urethra and linked to pathogen recognition. We here describe its properties and its link to defence mechanisms, showing parallels to similar sentinel cells in the respiratory and gastrointestinal tract. In the urethra, slender epithelial cells with apical microvilli ('brush cells') express bitter and umami taste receptors and the downstream signalling cascade known from oropharyngeal gustation, utilizing it to monitor for bacterial products and bacterial growth facilitating conditions. Upon stimulation, they release acetylcholine, and their sensitivity is subjected to cholinergic feedback. They are approached by cholinoceptive sensory nerve fibres, and intraurethral bitter application evokes reflex detrusor activity. Similar cells in the respiratory and gastrointestinal mucosa additionally regulate immune function through local neurogenic inflammation and cytokine release, triggered by bacterial products and parasites. This cell is interpreted to serve as chemosensory sentinel for potential hazardous compounds in the urethral lumen, triggering a protective mechanism (flushing through micturition) against further ascent. Dysfunction may be related to higher risk of infection or inadequate detrusor activity, pharmacological intervention may be considered to combat infection or detrusor overactivity.

Pharmacology of Drosophila Melanogaster TRPA1 Isoforms

The TRPA1 cation channel functions as a broadly-tuned chemonociceptor in many species. Recent studies identified several splice variants of Drosophila TRPA1 (from dTRPA1(A) to (D)). These were reported to display distinct chemical and thermal sensitivities and distinct expression patterns. Some differences in the chemical sensitivities between insect and mammalian orthologues have also been reported. Given the usefulness of Drosophila as animal model for studying TRPA1 chemosensation in vivo, we re-evaluated the effects of three mammalian TRPA1 modulators (nicotine, citronellal and menthol) on dTRPA1 splice variants in HEK293T cells. Using intracellular Ca2+ fluorimetry and whole-cell patch-clamp, we confirmed that the electrophilic agonist allyl isothiocyanate activates all splice variants, whereas nicotine activates all variants except dTRPA1(B). Citronellal robustly activated all splice variants. The activation by nicotine and citronellal could be inhibited by the TRPA1 antagonist HC030031. On the other hand, menthol did not activate any dTRPA1 isoform. Our results demonstrate that the mammalian heterologous expression system HEK293T can be used for functional studies on insect TRPA1 channels, and that the chemosensory properties of these channels may strongly differ from those of the mammalian homologues. Our findings serve as starting point for further structure-function studies for the determination of the structural bases of chemical sensitivity in TRPA1 channels.

The taste of heat: How humoral qualities act as a cultural filter for chemosensory properties guiding herbal medicine

Ethnopharmacological relevanceOrganoleptic properties, and more specifically chemosensory cues, have been shown to guide therapeutic applications of medicinal plants. Humoral qualities, on the other hand, are widely believed to be an abstract concept, mainly applied post hoc to validate therapy. However, the nexus between humoral qualities, chemosensory properties, and medicinal plant uses has never been systematically assessed. Aim of the studyTo systematically analyse the correlations between chemosensory properties, humoral qualities, and medicinal uses of selected botanical drugs. MethodsThe issue was approached experimentally via an organoleptic testing panel, consisting of Zoque healers in Chiapas, Mexico. The healers smelled and tasted 71 selected herbal drugs and subsequently commented on their humoral qualities and therapeutic uses. The resulting dataset is analysed for correlations between these variables using Bayesian statistics. Qualitative data on the characteristics and role of the hot-cold dichotomy complement the quantitative analysis, facilitating meaningful interpretation. Results and discussionThe results reproduce and extend the findings of previous studies, which established specific correlations between chemosensory cues and nosological units. The key predictors of drugs’ therapeutic uses, however, are their humoral qualities, which are themselves conditioned by taste and smell. These findings appear to be valid for drug samples known to the participants as well as for unfamiliar samples. Thus, this study establishes the role of the hot-cold dichotomy as an important cultural filter connecting organoleptic properties and therapeutic uses of herbal drugs. ConclusionsThere is considerable cross-cultural consensus in Mesoamerica for the specific correlations described in this study. Given the continued pervasiveness of the hot-cold dichotomy, humoral qualities and the underlying organoleptic properties ought to be increasingly considered in the design of pharmaceutical products as well as public health strategies. Such culturally appropriate adjustments may considerably improve the perceived quality and effectiveness of healthcare.

Polyoxy-Derivatized Perylenediimide as Selective Fluorescent Ag (I) Chemosensor.

Recent investigations indicated that same concentrations of the ionic silver have harmful effects on aquatic life, bacteria and human cells. Herein we report chemosensory properties of N,N ' -Bis(4-{2-[2-(2-methoxyethoxy)ethoxy] eth- oxy}phenyl) -3,4:9,10-perylene tetracarboxydiimide (PERKAT) towards ionic silver. The dye doped sensing agents were prepared utilizing ethyl cellulose (EC) and poly (methylmethacrylate) (PMMA) and then forwarded to electrospinning to prepare sensing fibers or mats. The PERKAT exhibited bright emission in embedded forms in EC or in the solvents of N,N-Dimethylformamide (DMF), Dichloromethane (DCM), Tetrahydrofurane (THF) and in the mixture of DCM/ethanol. The PERKAT exhibited selective and linear response for ionic silver in the concentration range of 10-10 - 10-5M Ag (I) at pH5.5. Detection limits were found to be 2.6×10-10 and 4.3×10-11M, in solution phase studies and PERKAT doped sensing films, respectively. Cross sensitivity of the PERKAT towards pH and some metal ions was also studied. There were no response for the Li+, Na+, K+, Ca2+, Ba2+, Mg2+, NH4+, Ni2+, Co2+, Cu2+,Pb2+, Al3+, Cr3+,Mn2+, Sn2+, Hg+, Hg2+, Fe2+ and Fe3+ in buffered solutions. To the best of our knowledge, this is the first study investigating silver sensing abilities of the PERKAT.

Market share for flavour capsule cigarettes is quickly growing, especially in Latin America

Flavour capsules in cigarette filters are a product design innovation that allows consumers to crush a liquid-filled capsule that flavours the cigarette smoke. Most capsules include menthol flavourings, with chemosensory...

Glia, sympathetic activity and cardiovascular disease.

New Findings What is the topic of this review? In this review, we discuss recent findings that provide a novel insight into the mechanisms that link glial cell function with the pathogenesis of cardiovascular disease, including systemic arterial hypertension and chronic heart failure. What advances does it highlight? We discuss how glial cells may influence central presympathetic circuits, leading to maladaptive and detrimental increases in sympathetic activity and contributing to the development and progression of cardiovascular disease. Increased activity of the sympathetic nervous system is associated with the development of cardiovascular disease and may contribute to its progression. Vasomotor and cardiac sympathetic activities are generated by the neuronal circuits located in the hypothalamus and the brainstem. These neuronal networks receive multiple inputs from the periphery and other parts of the CNS and, at a local level, may be influenced by their non‐neuronal neighbours, in particular glial cells. In this review, we discuss recent experimental evidence suggesting that astrocytes and microglial cells are able to modulate the activity of sympathoexcitatory neural networks in disparate physiological and pathophysiological conditions. We focus on the chemosensory properties of astrocytes residing in the rostral ventrolateral medulla oblongata and discuss signalling mechanisms leading to glial activation during brain hypoxia and inflammation. Alterations in these mechanisms may lead to heightened activity of sympathoexcitatory CNS circuits and contribute to maladaptive and detrimental increases in sympathetic tone associated with systemic arterial hypertension and chronic heart failure.

Broad Sensitivity of Drosophila Melanogaster TRPA1 to Noxious Chemicals

The TRPA1 ion channel functions as a broadly-tuned chemonociceptor in many species. In the fruit fly, Drosophila melanogaster, dTRPA1(A) is known to contribute to chemosensation for its expression in a subset of gustatory receptor neurons in the labral sense organ and in the labellum. These neurons also express a gustatory receptor Gr66a and mediate the avoidance of non-volatile compounds that are recognized by mammalian bitter taste receptors. In this study we aimed to further characterize the chemosensory properties of dTRPA1(A). This channel was reported to mediate the aversion towards citronellal, but to be activated indirectly through a G protein/PLC signalling cascade. We expressed the TRPA1(A) in a mammalian heterologous expression system. By use of the whole cell patch clamp technique, we were able to show that Citronellal activates TRPA1(A) in HEK293T cells. It has been recently shown that TRPA1 plays a role in the acute mammalian nocifensive responses to bacterial lipopolysaccharides (LPS). We hypothesized that dTRPA1 endows Drosophila fruit flies with the ability to detect LPS and to adopt avoiding behaviours towards this compound. Behavioural experiments showed that D. melanogaster flies avoid laying eggs on food contaminated with bacteria through mechanisms that are partly dependent on dTRPA1 activation. By use of the whole cell patch clamp technique we could illustrate the activation of dTRPA1(A) currents in HEK293T cells. Altogether, these experiments indicate for a direct role of TRPA1 in the detection and avoidance of a wide variety of noxious chemicals in D. melanogaster.

Synthesis and chemosensory properties of two-arm truxene-functionalized conjugated polyfluorene containing terpyridine moiety

We report the responsive fluorescence chemosensory phenomena of a truxene-functionalized conjugated polymer (P1) with pendant terminal terpyridine (tpy) groups as receptors for metal ions synthesized via a Suzuki polymerization reaction.

Chemosensory Properties of Pungent Spices: Their Role in Altering Nutrient Intake

The general population is not compliant with national dietary recommendations for promoting health and reducing chronic disease risk. While rising obesity rates suggest that the majority of the population is overconsuming, many individuals affected with either acute or chronic diseases struggle to maintain adequate dietary intake and are at high nutritional risk. Flavor is the primary driver of food intake; however, disliked flavors are a major barrier to consumer adherence with dietary recommendations for both groups. Spices that contribute to chemical burn—such as black pepper, garlic, ginger, mustard, oregano, red pepper, and wasabi—alter food flavors. This paper explores the role of these pungent spices in altering nutrient intake across the lifespan. The role of chemical burn in manipulating dietary intake in both diseased and healthy populations is discussed. Implications for using pungent spices to enhance compliance with dietary manipulations are described. Proposed functions of pungent spices are maintaining, preserving, and enhancing flavor to offset the reductions in liking and palatability that are associated with dietary modifications and disease status.

Synthesis and chemosensory properties of terpyridine-containing diblock polycarbazole through RAFT polymerization

This paper describes the synthesis of a terpyridine-containing diblock copolymer, poly(N-vinylcarbazole)-block-poly[4′-((4-vinylphenyl) phenyl)-2,2′:6′,2″- terpyridine] (poly(VK15-b-TPY4)), using the macro-chain transfer agent VK macro-CTA, and employing two-step reverse addition-fragmentation transfer (RAFT) polymerization. We examined the effect of terpyridine units on sensory characteristics of fluorescent chemosensors. VK macro-CTA and diblock copolymer poly(VK15-b-TPY4) both exhibited moderate thermal stability, with thermal decomposition temperatures of 5% weight losses at approximately 307°C and 378°C, respectively, suggesting that the enhancement of thermal stability was attributed to the incorporation of terpyridine segments into the block copolymer. Poly(VK15-b-TPY4) exhibited higher sensitivities to Ni2+ and Mn2+ ions, with Stern–Volmer constants (Ksv) of 2.58×105M−1 and 2.57×105M−1, respectively. Adding a Zn2+ ion not only caused partial fluorescence enhancement (3.2-fold quantum efficiency) but also induced a bathochromic shift of emission peak by approximately 56nm (from 429nm to 485nm), indicating that the Zn2+-terpyridine complex reduced the twist and vibration of the C–C polymer backbone and enhanced the charge transfer from donors to acceptors because of the more planar and rigid structure. Our results suggest that poly(VK15-b-TPY4) is a promising material for chemosensory applications.

Chemical coding and chemosensory properties of cholinergic brush cells in the mouse gastrointestinal and biliary tract.

The mouse gastro-intestinal and biliary tract mucosal epithelia harbor choline acetyltransferase (ChAT)-positive brush cells with taste cell-like traits. With the aid of two transgenic mouse lines that express green fluorescent protein (EGFP) under the control of the ChAT promoter (EGFPChAT) and by using in situ hybridization and immunohistochemistry we found that EGFPChAT cells were clustered in the epithelium lining the gastric groove. EGFPChAT cells were numerous in the gall bladder and bile duct, and found scattered as solitary cells along the small and large intestine. While all EGFPChAT cells were also ChAT-positive, expression of the high-affinity choline transporter (ChT1) was never detected. Except for the proximal colon, EGFPChAT cells also lacked detectable expression of the vesicular acetylcholine transporter (VAChT). EGFPChAT cells were found to be separate from enteroendocrine cells, however they were all immunoreactive for cytokeratin 18 (CK18), transient receptor potential melastatin-like subtype 5 channel (TRPM5), and for cyclooxygenases 1 (COX1) and 2 (COX2). The ex vivo stimulation of colonic EGFPChAT cells with the bitter substance denatonium resulted in a strong increase in intracellular calcium, while in other epithelial cells such an increase was significantly weaker and also timely delayed. Subsequent stimulation with cycloheximide was ineffective in both cell populations. Given their chemical coding and chemosensory properties, EGFPChAT brush cells thus may have integrative functions and participate in induction of protective reflexes and inflammatory events by utilizing ACh and prostaglandins for paracrine signaling.

Prenatal alcohol exposure selectively enhances young adult perceived pleasantness of alcohol odors

Prenatal alcohol exposure (PAE) can lead to life-long neurobehavioral and social problems that can include a greater likelihood of early use and/or abuse of alcohol compared to older teens and young adults without PAE. Basic research in animals demonstrates that PAE influences later postnatal responses to chemosensory cues (i.e., odor & taste) associated with alcohol. We hypothesized that PAE would be related to poorer abilities to identify odors of alcohol-containing beverages, and would alter perceived alcohol odor intensity and pleasantness. To address this hypothesis we examined responses to alcohol and other odors in a small sample of young adults with detailed prenatal histories of exposure to alcohol and other drugs. The key finding from our controlled analyses is that higher levels of PAE were related to higher relative ratings of pleasantness for alcohol odors. As far as we are aware, this is the first published study to report the influence of PAE on responses to alcohol beverage odors in young adults. These findings are consistent with the hypothesis that positive associations (i.e., “pleasantness”) to the chemosensory properties of alcohol (i.e., odor) are acquired prenatally and are retained for many years despite myriad interceding postnatal experiences. Alternate hypotheses may also be supported by the results. There are potential implications of altered alcohol odor responses for understanding individual differences in initiation of drinking, and alcohol seeking and high-risk alcohol-related behaviors in young adults.

Cooling Down TRP Channel: Cold and Chemo-Sensitivity of the Human TRPA1

Transient receptor potential (TRP) channels are an important class of receptors found widely distributed throughout the mammalian central and peripheral nervous systems. They have been shown to be activated and regulated by a variety of stimuli including temperature, mechano-stimulation and different kinds of molecules, which mediate the sensation of taste, as well as divalent cations and pH. Dysfunction of TRP channel can cause various pathological conditions, including an inherited pain syndrome, multiple kidney diseases and skeletal disorders. Hence, TRP channel become potential targets for the treatment of such disorders.Patch clamp electrophysiology remains the gold standard for studying ion channels. We have employed a planar patch clamp technology to study the purified human TRPA1 channel (hTRPA1). Solvent-free planar lipid bilayers can be formed in an automated fashion by positioning and subsequent bursting of giant unilamellar lipid vesicles containing ion channels, here hTRPA1, on the Port-a-Patch micron-sized apertures borosilicate glass substrate.In this study, the human TRPA1 was purified and reconstituted into lipid bilayers and single channel currents were recorded to understand the thermo- and chemosensory properties of the channel together with the role of the N-terminal ankyrin repeat domain (ARD). We report that hTRPA1with and without its N-terminal ARD is intrinsically cold-sensitive, and thus cold sensing properties of hTRPA1 reside outside the N-terminal ARD.Furthermore, hTRPA1 is activated by a range of environmental irritants, pungent compounds found in foods such as garlic, mustard and cinnamon, as well as metabolites produced during oxidative stress. Data will be presented showing activation and inhibition of the hTRPA1 channel reconstituted in bilayers as well as hTRPA1 expressed in HEK cells (Millipore), using the SyncroPatch 384PE planar patch clamp platform, by a variety of agonists and antagonists.