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Sample records for non-conventional olfactory receptor

  1. Expression and evolutionary divergence of the non-conventional olfactory receptor in four species of fig wasp associated with one species of fig

    PubMed Central

    Lu, Bin; Wang, Nina; Xiao, Jinhua; Xu, Yongyu; Murphy, Robert W; Huang, Dawei

    2009-01-01

    Background The interactions of fig wasps and their host figs provide a model for investigating co-evolution. Fig wasps have specialized morphological characters and lifestyles thought to be adaptations to living in the fig's syconium. Although these aspects of natural history are well documented, the genetic mechanism(s) underlying these changes remain(s) unknown. Fig wasp olfaction is the key to host-specificity. The Or83b gene class, an unusual member of olfactory receptor family, plays a critical role in enabling the function of conventional olfactory receptors. Four Or83b orthologous genes from one pollinator (PFW) (Ceratosolen solmsi) and three non-pollinator fig wasps (NPFWs) (Apocrypta bakeri, Philotrypesis pilosa and Philotrypesis sp.) associated with one species of fig (Ficus hispida) can be used to better understand the molecular mechanism underlying the fig wasp's adaptation to its host. We made a comparison of spatial tissue-specific expression patterns and substitution rates of one orthologous gene in these fig wasps and sought evidence for selection pressures. Results A newly identified Or83b orthologous gene was named Or2. Expressions of Or2 were restricted to the heads of all wingless male fig wasps, which usually live in the dark cavity of a fig throughout their life cycle. However, expressions were widely detected in the antennae, legs and abdomens of all female fig wasps that fly from one fig to another for oviposition, and secondarily pollination. Weak expression was also observed in the thorax of PFWs. Compared with NPFWs, the Or2 gene in C. solmsi had an elevated rate of substitutions and lower codon usage. Analyses using Tajima's D, Fu and Li's D* and F* tests indicated a non-neutral pattern of nucleotide variation in all fig wasps. Unlike in NPFWs, this non-neutral pattern was also observed for synonymous sites of Or2 within PFWs. Conclusion The sex- and species-specific expression patterns of Or2 genes detected beyond the known primary

  2. Ionotropic Crustacean Olfactory Receptors

    PubMed Central

    Corey, Elizabeth A.; Bobkov, Yuriy; Ukhanov, Kirill; Ache, Barry W.

    2013-01-01

    The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs), the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs), as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling. PMID:23573266

  3. Computational Biology of Olfactory Receptors

    PubMed Central

    Crasto, Chiquito J.

    2011-01-01

    Olfactory receptors, in addition to being involved in first step of the physiological processes that leads to olfaction, occupy an important place in mammalian genomes. ORs constitute super families in these genomes. Elucidating ol-factory receptor function at a molecular level can be aided by a computationally derived structure and an understanding of its interactions with odor molecules. Experimental functional analyses of olfactory receptors in conjunction with computational studies serve to validate findings and generate hypotheses. We present here a review of the research efforts in: creating computational models of olfactory receptors, identifying binding strategies for these receptors with odorant molecules, performing medium to long range simulation studies of odor ligands in the receptor binding region, and identifying amino acid positions within the receptor that are responsible for ligand-binding and olfactory receptor activation. Written as a primer and a teaching tool, this review will help researchers extend the methodologies described herein to other GPCRs. PMID:21984880

  4. Olfactory receptor signaling.

    PubMed

    Antunes, Gabriela; Simoes de Souza, Fabio Marques

    2016-01-01

    The guanine nucleotide protein (G protein)-coupled receptors (GPCRs) superfamily represents the largest class of membrane protein in the human genome. More than a half of all GPCRs are dedicated to interact with odorants and are termed odorant-receptors (ORs). Linda Buck and Richard Axel, the Nobel Prize laureates in physiology or medicine in 2004, first cloned and characterized the gene family that encode ORs, establishing the foundations to the understanding of the molecular basis for odor recognition. In the last decades, a lot of progress has been done to unravel the functioning of the sense of smell. This chapter gives a general overview of the topic of olfactory receptor signaling and reviews recent advances in this field. PMID:26928542

  5. Monoallelic Expression of Olfactory Receptors

    PubMed Central

    Monahan, Kevin; Lomvardas, Stavros

    2016-01-01

    The sense of smell collects vital information about the environment by detecting a multitude of chemical odorants. Breadth and sensitivity are provided by a huge number of chemosensory receptor proteins, including more than 1,400 olfactory receptors (ORs). Organizing the sensory information generated by these receptors so that it can be processed and evaluated by the central nervous system is a major challenge. This challenge is overcome by monogenic and monoallelic expression of OR genes. The single OR expressed by each olfactory sensory neuron determines the neuron’s odor sensitivity and the axonal connections it will make to downstream neurons in the olfactory bulb. The expression of a single OR per neuron is accomplished by coupling a slow chromatin-mediated activation process to a fast negative-feedback signal that prevents activation of additional ORs. Singular OR activation is likely orchestrated by a network of interchromosomal enhancer interactions and large-scale changes in nuclear architecture. PMID:26359778

  6. Evolution of insect olfactory receptors

    PubMed Central

    Missbach, Christine; Dweck, Hany KM; Vogel, Heiko; Vilcinskas, Andreas; Stensmyr, Marcus C; Hansson, Bill S; Grosse-Wilde, Ewald

    2014-01-01

    The olfactory sense detects a plethora of behaviorally relevant odor molecules; gene families involved in olfaction exhibit high diversity in different animal phyla. Insects detect volatile molecules using olfactory (OR) or ionotropic receptors (IR) and in some cases gustatory receptors (GRs). While IRs are expressed in olfactory organs across Protostomia, ORs have been hypothesized to be an adaptation to a terrestrial insect lifestyle. We investigated the olfactory system of the primary wingless bristletail Lepismachilis y-signata (Archaeognatha), the firebrat Thermobia domestica (Zygentoma) and the neopteran leaf insect Phyllium siccifolium (Phasmatodea). ORs and the olfactory coreceptor (Orco) are with very high probability lacking in Lepismachilis; in Thermobia we have identified three Orco candidates, and in Phyllium a fully developed OR/Orco-based system. We suggest that ORs did not arise as an adaptation to a terrestrial lifestyle, but evolved later in insect evolution, with Orco being present before the appearance of ORs. DOI: http://dx.doi.org/10.7554/eLife.02115.001 PMID:24670956

  7. Olfactory receptor neuron profiling using sandalwood odorants.

    PubMed

    Bieri, Stephan; Monastyrskaia, Katherine; Schilling, Boris

    2004-07-01

    The mammalian olfactory system can discriminate between volatile molecules with subtle differences in their molecular structures. Efforts in synthetic chemistry have delivered a myriad of smelling compounds of different qualities as well as many molecules with very similar olfactive properties. One important class of molecules in the fragrance industry are sandalwood odorants. Sandalwood oil and four synthetic sandalwood molecules were selected to study the activation profile of endogenous olfactory receptors when exposed to compounds from the same odorant family. Dissociated rat olfactory receptor neurons were exposed to the sandalwood molecules and the receptor activation studied by monitoring fluxes in the internal calcium concentration. Olfactory receptor neurons were identified that were specifically stimulated by sandalwood compounds. These neurons expressed olfactory receptors that can discriminate between sandalwood odorants with slight differences in their molecular structures. This is the first study in which an important class of perfume compounds was analyzed for its ability to activate endogenous olfactory receptors in olfactory receptor neurons.

  8. The human olfactory receptor repertoire

    PubMed Central

    Zozulya, Sergey; Echeverri, Fernando; Nguyen, Trieu

    2001-01-01

    Background The mammalian olfactory apparatus is able to recognize and distinguish thousands of structurally diverse volatile chemicals. This chemosensory function is mediated by a very large family of seven-transmembrane olfactory (odorant) receptors encoded by approximately 1,000 genes, the majority of which are believed to be pseudogenes in humans. Results The strategy of our sequence database mining for full-length, functional candidate odorant receptor genes was based on the high overall sequence similarity and presence of a number of conserved sequence motifs in all known mammalian odorant receptors as well as the absence of introns in their coding sequences. We report here the identification and physical cloning of 347 putative human full-length odorant receptor genes. Comparative sequence analysis of the predicted gene products allowed us to identify and define a number of consensus sequence motifs and structural features of this vast family of receptors. A new nomenclature for human odorant receptors based on their chromosomal localization and phylogenetic analysis is proposed. We believe that these sequences represent the essentially complete repertoire of functional human odorant receptors. Conclusions The identification and cloning of all functional human odorant receptor genes is an important initial step in understanding receptor-ligand specificity and combinatorial encoding of odorant stimuli in human olfaction. PMID:11423007

  9. Olfactory Receptor Patterning in a Higher Primate

    PubMed Central

    Horowitz, Lisa F.; Saraiva, Luis R.; Kuang, Donghui; Yoon, Kyoung-hye

    2014-01-01

    The mammalian olfactory system detects a plethora of environmental chemicals that are perceived as odors or stimulate instinctive behaviors. Studies using odorant receptor (OR) genes have provided insight into the molecular and organizational strategies underlying olfaction in mice. One important unanswered question, however, is whether these strategies are conserved in primates. To explore this question, we examined the macaque, a higher primate phylogenetically close to humans. Here we report that the organization of sensory inputs in the macaque nose resembles that in mouse in some respects, but not others. As in mouse, neurons with different ORs are interspersed in the macaque nose, and there are spatial zones that differ in their complement of ORs and extend axons to different domains in the olfactory bulb of the brain. However, whereas the mouse has multiple discrete band-like zones, the macaque appears to have only two broad zones. It is unclear whether the organization of OR inputs in a rodent/primate common ancestor degenerated in primates or, alternatively became more sophisticated in rodents. The mouse nose has an additional small family of chemosensory receptors, called trace amine-associated receptors (TAARs), which may detect social cues. Here we find that TAARs are also expressed in the macaque nose, suggesting that TAARs may also play a role in human olfactory perception. We further find that one human TAAR responds to rotten fish, suggesting a possible role as a sentinel to discourage ingestion of food harboring pathogenic microorganisms. PMID:25209267

  10. Olfactory receptors: G protein-coupled receptors and beyond.

    PubMed

    Spehr, Marc; Munger, Steven D

    2009-06-01

    Sensing the chemical environment is critical for all organisms. Diverse animals from insects to mammals utilize highly organized olfactory system to detect, encode, and process chemostimuli that may carry important information critical for health, survival, social interactions and reproduction. Therefore, for animals to properly interpret and react to their environment it is imperative that the olfactory system recognizes chemical stimuli with appropriate selectivity and sensitivity. Because olfactory receptor proteins play such an essential role in the specific recognition of diverse stimuli, understanding how they interact with and transduce their cognate ligands is a high priority. In the nearly two decades since the discovery that the mammalian odorant receptor gene family constitutes the largest group of G protein-coupled receptor (GPCR) genes, much attention has been focused on the roles of GPCRs in vertebrate and invertebrate olfaction. However, is has become clear that the 'family' of olfactory receptors is highly diverse, with roles for enzymes and ligand-gated ion channels as well as GPCRs in the primary detection of olfactory stimuli. PMID:19383089

  11. Functional architecture of olfactory ionotropic glutamate receptors

    PubMed Central

    Abuin, Liliane; Bargeton, Benoîte; Ulbrich, Maximilian H.; Isacoff, Ehud Y.; Kellenberger, Stephan; Benton, Richard

    2010-01-01

    Ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels that mediate chemical communication between neurons at synapses. A variant iGluR subfamily, the Ionotropic Receptors (IRs), was recently proposed to detect environmental volatile chemicals in olfactory cilia. Here we elucidate how these peripheral chemosensors have evolved mechanistically from their iGluR ancestors. Using a Drosophila model, we demonstrate that IRs act in combinations of up to three subunits, comprising individual odor-specific receptors and one or two broadly expressed co-receptors. Heteromeric IR complex formation is necessary and sufficient for trafficking to cilia and mediating odor-evoked electrophysiological responses in vivo and in vitro. IRs display heterogeneous ion conduction specificities related to their variable pore sequences, and divergent ligand-binding domains function in odor recognition and cilia localization. Our results provide insights into the conserved and distinct architecture of these olfactory and synaptic ion channels and offer perspectives into use of IRs as genetically encoded chemical sensors. PMID:21220098

  12. [Hypothesis on the function of olfactory receptor cells].

    PubMed

    Smirnov, A A

    1995-01-01

    The scientific studies of sensory systems (including olfactory organs) are carried out during a century. Usually a preliminary theory of object is suggested and detailed in accordance with the new data. However only the strong criticized theories of smell reception more than thirty) are now in the theoretical part of the olfactory organ physiology. The theory is necessary for planning the further investigations of olfactory organ; revealing the mystery of the biological sensors to improve the artificial ones; the improvement of the methods to obtain new biological active substances (perfume, drugs, insecticides). These circumstances justify the attempt to suggest the theory of the olfactory receptor cell functioning.

  13. Serotonin modulates outward potassium currents in mouse olfactory receptor neurons.

    PubMed

    Gao, S; Guo, X; Liu, T; Liu, J; Chen, W; Xia, Q; Chen, Y; Tang, Y

    2013-01-01

    Monoaminergic neurotransmitter 5-hydroxytryptamine (5-HT), also known as serotonin, plays important roles in modulating the function of the olfactory system. However, thus far, the knowledge about 5-HT and its receptors in olfactory receptor neurons (ORNs) and their physiological role have not been fully characterized. In the present study, reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed the presence of 5-HT(1A) and 5-HT(1B) receptor subtypes in mouse olfactory epithelium at the mRNA level. With subtype selective antibodies and standard immunohistochemical techniques, both receptor subtypes were found to be positively labeled. To further elucidate the molecular mechanisms of 5-HT act on the peripheral olfactory transduction, the whole-cell patch clamp techniques were used on freshly isolated ORNs. We found that 5-HT decreased the magnitude of outward K(+) current in a dose-dependent manner and these inhibitory effects were markedly attenuated by the 5-HT(1A) receptor blocker WAY-100635 and the 5-HT(1B) receptor antagonist GR55562. These data suggested that 5-HT may play a role in the modulation of peripheral olfactory signals by regulating outward potassium currents, both 5-HT(1A) and 5-HT(1B) receptors were involved in this regulation.

  14. Olfactory sensations produced by high-energy photon irradiation of the olfactory receptor mucosa in humans

    SciTech Connect

    Sagar, S.M.; Thomas, R.J.; Loverock, L.T.; Spittle, M.F. )

    1991-04-01

    During irradiation of volumes that incorporate the olfactory system, a proportion of patients have complained of a pungent smell. A retrospective study was carried out to determine the prevalence of this side-effect. A questionnaire was sent to 40 patients whose treatment volumes included the olfactory region and also to a control group treated away from this region. The irradiated tumor volumes included the frontal lobe, whole brain, nasopharynx, pituitary fossa, and maxillary antrum. Of the 25 patients who replied, 60% experienced odorous symptoms during irradiation. They described the odor as unpleasant and consistent with ozone. Stimulation of olfactory receptors is considered to be caused by the radiochemical formation of ozone and free radicals in the mucus overlying the olfactory mucosa.

  15. Deep Sequencing of the Murine Olfactory Receptor Neuron Transcriptome

    PubMed Central

    Kanageswaran, Ninthujah; Demond, Marilen; Nagel, Maximilian; Schreiner, Benjamin S. P.; Baumgart, Sabrina; Scholz, Paul; Altmüller, Janine; Becker, Christian; Doerner, Julia F.; Conrad, Heike; Oberland, Sonja; Wetzel, Christian H.; Neuhaus, Eva M.; Hatt, Hanns; Gisselmann, Günter

    2015-01-01

    The ability of animals to sense and differentiate among thousands of odorants relies on a large set of olfactory receptors (OR) and a multitude of accessory proteins within the olfactory epithelium (OE). ORs and related signaling mechanisms have been the subject of intensive studies over the past years, but our knowledge regarding olfactory processing remains limited. The recent development of next generation sequencing (NGS) techniques encouraged us to assess the transcriptome of the murine OE. We analyzed RNA from OEs of female and male adult mice and from fluorescence-activated cell sorting (FACS)-sorted olfactory receptor neurons (ORNs) obtained from transgenic OMP-GFP mice. The Illumina RNA-Seq protocol was utilized to generate up to 86 million reads per transcriptome. In OE samples, nearly all OR and trace amine-associated receptor (TAAR) genes involved in the perception of volatile amines were detectably expressed. Other genes known to participate in olfactory signaling pathways were among the 200 genes with the highest expression levels in the OE. To identify OE-specific genes, we compared olfactory neuron expression profiles with RNA-Seq transcriptome data from different murine tissues. By analyzing different transcript classes, we detected the expression of non-olfactory GPCRs in ORNs and established an expression ranking for GPCRs detected in the OE. We also identified other previously undescribed membrane proteins as potential new players in olfaction. The quantitative and comprehensive transcriptome data provide a virtually complete catalogue of genes expressed in the OE and present a useful tool to uncover candidate genes involved in, for example, olfactory signaling, OR trafficking and recycling, and proliferation. PMID:25590618

  16. Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila

    PubMed Central

    Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I.; Angel, Cristian; Campusano, Jorge M.

    2015-01-01

    The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila. PMID:26380118

  17. Phosphoinositide 3-kinase mediated signaling in lobster olfactory receptor neurons.

    PubMed

    Corey, Elizabeth A; Bobkov, Yuriy; Pezier, Adeline; Ache, Barry W

    2010-04-01

    In vertebrates and some invertebrates, odorant molecules bind to G protein-coupled receptors on olfactory receptor neurons (ORNs) to initiate signal transduction. Phosphoinositide 3-kinase (PI3K) activity has been implicated physiologically in olfactory signal transduction, suggesting a potential role for a G protein-coupled receptor-activated class I PI3K. Using isoform-specific antibodies, we identified a protein in the olfactory signal transduction compartment of lobster ORNs that is antigenically similar to mammalian PI3Kgamma and cloned a gene for a PI3K with amino acid homology with PI3Kbeta. The lobster olfactory PI3K co-immunoprecipitates with the G protein alpha and beta subunits, and an odorant-evoked increase in phosphatidylinositol (3,4,5)-trisphosphate can be detected in the signal transduction compartment of the ORNs. PI3Kgamma and beta isoform-specific inhibitors reduce the odorant-evoked output of lobster ORNs in vivo. Collectively, these findings provide evidence that PI3K is indeed activated by odorant receptors in lobster ORNs and further support the potential involvement of G protein activated PI3K signaling in olfactory transduction.

  18. Suppression of Odorant Responses by Odorants in Olfactory Receptor Cells

    NASA Astrophysics Data System (ADS)

    Kurahashi, Takashi; Lowe, Graeme; Gold, Geoffrey H.

    1994-07-01

    Odorants activate an inward current in vertebrate olfactory receptor cells. Here it is shown, in receptor cells from the newt, that odorants can also suppress this current, by a mechanism that is distinct from inhibition and adaptation. Suppression provides a simple explanation for two seemingly unrelated phenomena: the anomalously long latency of olfactory transduction and the existence of an "off response" at the end of a prolonged stimulus. Suppression may influence the perception of odorants by masking odorant responses and by sharpening the odorant specificities of single cells.

  19. Central loop of non-conventional toxin WTX from Naja kaouthia is important for interaction with nicotinic acetylcholine receptors.

    PubMed

    Lyukmanova, Ekaterina N; Shulepko, Mikhail A; Shenkarev, Zakhar O; Kasheverov, Igor E; Chugunov, Anton O; Kulbatskii, Dmitrii S; Myshkin, Mikhail Yu; Utkin, Yuri N; Efremov, Roman G; Tsetlin, Victor I; Arseniev, Alexander S; Kirpichnikov, Mikhail P; Dolgikh, Dmitry A

    2016-09-01

    'Three-finger' toxin WTX from Naja kaouthia interacts with nicotinic and muscarinic acetylcholine receptors (nAChRs and mAChRs). Mutagenesis and competition experiments with (125)I-α-bungarotoxin revealed that Arg31 and Arg32 residues from the WTX loop II are important for binding to Torpedo californica and human α7 nAChRs. Computer modeling suggested that loop II occupies the orthosteric binding site at α7 nAChR. The similar toxin interface was previously described as a major determinant of allosteric interactions with mAChRs. PMID:27343701

  20. Circadian Regulation of Olfactory Receptor Neurons in the Cockroach Antenna

    PubMed Central

    Saifullah, A.S.M.; Page, Terry L.

    2013-01-01

    In the cockroach, olfactory sensitivity as measured by the amplitude of the electroantennogram (EAG) is regulated by the circadian system. We wished to determine how this rhythm in antennal response was reflected in the activity of individual olfactory receptor neurons. The amplitude of the electroantennogram (EAG) and the activity of olfactory receptor neurons (ORNs) in single olfactory sensilla were recorded simultaneously for 3–5 days in constant darkness from an antenna of the cockroach Leucophaea maderae. Both EAG amplitude and the spike frequency of the ORNs exhibited circadian rhythms with peak amplitude/activity occurring in the subjective day. The phases of the rhythms were dependent on the phase of the prior light cycle and thus were entrainable by light. Ablation of the optic lobes abolished the rhythm in EAG amplitude as has been previously reported. In contrast, the rhythm in ORN response persisted following surgery. These results indicated that a circadian clock outside the optic lobes can regulate the responses of olfactory receptor neurons and further that this modulation of the ORN response is not dependent on the circadian rhythm in EAG amplitude. PMID:19346451

  1. Disruption of Olfactory Receptor Neuron Patterning in Scutoid mutant Drosophila

    PubMed Central

    Tom, W.; de Bruyne, M.; Haehnel, M.; Carlson, J. R.; Ray, A.

    2010-01-01

    Olfactory neurons show an extreme diversity of cell types with each cell usually expressing one member from a large family of 60 Odorant receptor (Or)genes in Drosophila. Little is known about the developmental processes and transcription factors that generate this stereotyped pattern of cellular diversity. Here we investigate the molecular and cellular basis of defects in olfactory system function in an unusual dominant mutant, Scutoid. We show that the defects map to olfactory neurons innervating a specific morphological class of sensilla on the antenna, large basiconics. Molecular analysis indicates defects in neurons expressing specific classes of receptor genes that map to large basiconic sensilla. Previous studies have shown that in Scutoid mutants the coding region of the transcriptional repressor snail is translocated near the no-ocelli promoter, leading to misexpression of snail in the developing eye-antenna disc. We show that ectopic expression of snail in developing olfactory neurons leads to severe defects in neurons of the antennal large basiconics supporting the model that the dominant olfactory phenotype in Scutoid is caused by misexpression of snail. PMID:20875862

  2. Chromatin Modulatory Proteins and Olfactory Receptor Signaling in the Refinement and Maintenance of Fruitless Expression in Olfactory Receptor Neurons

    PubMed Central

    Li, Qingyun; Okuwa, Sumie; Peng, Bo; Wu, Jianni; Volkan, Pelin Cayirlioglu

    2016-01-01

    During development, sensory neurons must choose identities that allow them to detect specific signals and connect with appropriate target neurons. Ultimately, these sensory neurons will successfully integrate into appropriate neural circuits to generate defined motor outputs, or behavior. This integration requires a developmental coordination between the identity of the neuron and the identity of the circuit. The mechanisms that underlie this coordination are currently unknown. Here, we describe two modes of regulation that coordinate the sensory identities of Drosophila melanogaster olfactory receptor neurons (ORNs) involved in sex-specific behaviors with the sex-specific behavioral circuit identity marker fruitless (fru). The first mode involves a developmental program that coordinately restricts to appropriate ORNs the expression of fru and two olfactory receptors (Or47b and Ir84a) involved in sex-specific behaviors. This regulation requires the chromatin modulatory protein Alhambra (Alh). The second mode relies on the signaling from the olfactory receptors through CamK and histone acetyl transferase p300/CBP to maintain ORN-specific fru expression. Our results highlight two feed-forward regulatory mechanisms with both developmentally hardwired and olfactory receptor activity-dependent components that establish and maintain fru expression in ORNs. Such a dual mechanism of fru regulation in ORNs might be a trait of neurons driving plastic aspects of sex-specific behaviors. PMID:27093619

  3. Early Expression of Odorant Receptors Distorts the Olfactory Circuitry

    PubMed Central

    Nguyen, Minh Q.; Marks, Carolyn A.; Belluscio, Leonardo; Ryba, Nicholas J. P.

    2010-01-01

    The odor response properties of a mammalian olfactory sensory neuron (OSN) are determined by the tightly regulated expression of a single member of a very large family of odorant receptors (ORs). The OR also plays an important role in focusing the central projections of all OSNs expressing that particular receptor to a pair of stereotypic locations (glomeruli) in each olfactory bulb (OB), thus creating a spatial map of odor responses in the brain. Here we show that when initiated late in neural development, transgenic expression of one OR in almost all OSNs has little influence on the architecture of the OB. In contrast, early OR-transgene expression (mediated by the Gγ8-promoter) in 50–70% of OSNs grossly distorts the morphology of glomeruli and alters the projection patterns of many residual OSNs not expressing the transgene. Interestingly, this disruption of targeting persists in adult animals despite down-regulation of Gγ8 and transgenic OR expression that occurs as olfactory neurogenesis declines. Indeed, functional imaging studies reveal a dramatic decrease in the complexity of responses to odorants in adult Gγ8-transgenic OR mice. Thus, we show that initiation of transgenic OR-expression early in the development of OSNs, rather than just the extent of transgene expression, determines its effectiveness at modifying OB anatomy and function. Taken together these data imply that OR-expression timing needs to be very tightly controlled to achieve the precise wiring and function of the mammalian olfactory system. PMID:20610762

  4. Genetic basis of olfactory cognition: extremely high level of DNA sequence polymorphism in promoter regions of the human olfactory receptor genes revealed using the 1000 Genomes Project dataset

    PubMed Central

    Ignatieva, Elena V.; Levitsky, Victor G.; Yudin, Nikolay S.; Moshkin, Mikhail P.; Kolchanov, Nikolay A.

    2014-01-01

    The molecular mechanism of olfactory cognition is very complicated. Olfactory cognition is initiated by olfactory receptor proteins (odorant receptors), which are activated by olfactory stimuli (ligands). Olfactory receptors are the initial player in the signal transduction cascade producing a nerve impulse, which is transmitted to the brain. The sensitivity to a particular ligand depends on the expression level of multiple proteins involved in the process of olfactory cognition: olfactory receptor proteins, proteins that participate in signal transduction cascade, etc. The expression level of each gene is controlled by its regulatory regions, and especially, by the promoter [a region of DNA about 100–1000 base pairs long located upstream of the transcription start site (TSS)]. We analyzed single nucleotide polymorphisms using human whole-genome data from the 1000 Genomes Project and revealed an extremely high level of single nucleotide polymorphisms in promoter regions of olfactory receptor genes and HLA genes. We hypothesized that the high level of polymorphisms in olfactory receptor promoters was responsible for the diversity in regulatory mechanisms controlling the expression levels of olfactory receptor proteins. Such diversity of regulatory mechanisms may cause the great variability of olfactory cognition of numerous environmental olfactory stimuli perceived by human beings (air pollutants, human body odors, odors in culinary etc.). In turn, this variability may provide a wide range of emotional and behavioral reactions related to the vast variety of olfactory stimuli. PMID:24715883

  5. Biomimetic chemical sensors using nanoelectronic readout of olfactory receptor proteins.

    PubMed

    Goldsmith, Brett R; Mitala, Joseph J; Josue, Jesusa; Castro, Ana; Lerner, Mitchell B; Bayburt, Timothy H; Khamis, Samuel M; Jones, Ryan A; Brand, Joseph G; Sligar, Stephen G; Luetje, Charles W; Gelperin, Alan; Rhodes, Paul A; Discher, Bohdana M; Johnson, A T Charlie

    2011-07-26

    We have designed and implemented a practical nanoelectronic interface to G-protein coupled receptors (GPCRs), a large family of membrane proteins whose roles in the detection of molecules outside eukaryotic cells make them important pharmaceutical targets. Specifically, we have coupled olfactory receptor proteins (ORs) with carbon nanotube transistors. The resulting devices transduce signals associated with odorant binding to ORs in the gas phase under ambient conditions and show responses that are in excellent agreement with results from established assays for OR-ligand binding. The work represents significant progress on a path toward a bioelectronic nose that can be directly compared to biological olfactory systems as well as a general method for the study of GPCR function in multiple domains using electronic readout.

  6. Biomimetic Chemical Sensors Using Nanoelectronic Readout of Olfactory Receptor Proteins

    PubMed Central

    Goldsmith, Brett R.; Mitala, Joseph J.; Josue, Jesusa; Castro, Ana; Lerner, Mitchell B.; Bayburt, Timothy H.; Khamis, Samuel M.; Jones, Ryan A.; Brand, Joseph G.; Sligar, Stephen G.; Luetje, Charles W.; Gelperin, Alan; Rhodes, Paul A.; Discher, Bohdana M.; Johnson, A. T. Charlie

    2014-01-01

    We have designed and implemented a practical nanoelectronic interface to G-protein coupled receptors (GPCRs), a large family of membrane proteins whose roles in the detection of molecules outside eukaryotic cells make them important pharmaceutical targets. Specifically, we have coupled olfactory receptor proteins (ORs) with carbon nanotube transistors. The resulting devices transduce signals associated with odorant binding to ORs in the gas phase under ambient conditions and show responses that are in excellent agreement with results from established assays for OR–ligand binding. The work represents significant progress on a path toward a bioelectronic nose that can be directly compared to biological olfactory systems as well as a general method for the study of GPCR function in multiple domains using electronic readout. PMID:21696137

  7. A Renal Olfactory Receptor Aids in Kidney Glucose Handling

    PubMed Central

    Shepard, Blythe D.; Cheval, Lydie; Peterlin, Zita; Firestein, Stuart; Koepsell, Hermann; Doucet, Alain; Pluznick, Jennifer L.

    2016-01-01

    Olfactory receptors (ORs) are G protein-coupled receptors which serve important sensory functions beyond their role as odorant detectors in the olfactory epithelium. Here we describe a novel role for one of these ORs, Olfr1393, as a regulator of renal glucose handling. Olfr1393 is specifically expressed in the kidney proximal tubule, which is the site of renal glucose reabsorption. Olfr1393 knockout mice exhibit urinary glucose wasting and improved glucose tolerance, despite euglycemia and normal insulin levels. Consistent with this phenotype, Olfr1393 knockout mice have a significant decrease in luminal expression of Sglt1, a key renal glucose transporter, uncovering a novel regulatory pathway involving Olfr1393 and Sglt1. In addition, by utilizing a large scale screen of over 1400 chemicals we reveal the ligand profile of Olfr1393 for the first time, offering new insight into potential pathways of physiological regulation for this novel signaling pathway. PMID:27739476

  8. Olfactory Receptor Subgenomes Linked with Broad Ecological Adaptations in Sauropsida.

    PubMed

    Khan, Imran; Yang, Zhikai; Maldonado, Emanuel; Li, Cai; Zhang, Guojie; Gilbert, M Thomas P; Jarvis, Erich D; O'Brien, Stephen J; Johnson, Warren E; Antunes, Agostinho

    2015-11-01

    Olfactory receptors (ORs) govern a prime sensory function. Extant birds have distinct olfactory abilities, but the molecular mechanisms underlining diversification and specialization remain mostly unknown. We explored OR diversity in 48 phylogenetic and ecologically diverse birds and 2 reptiles (alligator and green sea turtle). OR subgenomes showed species- and lineage-specific variation related with ecological requirements. Overall 1,953 OR genes were identified in reptiles and 16,503 in birds. The two reptiles had larger OR gene repertoires (989 and 964 genes, respectively) than birds (182-688 genes). Overall, birds had more pseudogenes (7,855) than intact genes (1,944). The alligator had significantly more functional genes than sea turtle, likely because of distinct foraging habits. We found rapid species-specific expansion and positive selection in OR14 (detects hydrophobic compounds) in birds and in OR51 and OR52 (detect hydrophilic compounds) in sea turtle, suggestive of terrestrial and aquatic adaptations, respectively. Ecological partitioning among birds of prey, water birds, land birds, and vocal learners showed that diverse ecological factors determined olfactory ability and influenced corresponding olfactory-receptor subgenome. OR5/8/9 was expanded in predatory birds and alligator, suggesting adaptive specialization for carnivory. OR families 2/13, 51, and 52 were correlated with aquatic adaptations (water birds), OR families 6 and 10 were more pronounced in vocal-learning birds, whereas most specialized land birds had an expanded OR family 14. Olfactory bulb ratio (OBR) and OR gene repertoire were correlated. Birds that forage for prey (carnivores/piscivores) had relatively complex OBR and OR gene repertoires compared with modern birds, including passerines, perhaps due to highly developed cognitive capacities facilitating foraging innovations. PMID:26219582

  9. Mimicking nature's noses: from receptor deorphaning to olfactory biosensing.

    PubMed

    Glatz, Richard; Bailey-Hill, Kelly

    2011-02-01

    The way in which organisms detect specific volatile compounds within their environment, and the associated neural processing which produces perception and subsequent behavioural responses, have been of interest to scientists for decades. Initially, most olfaction research was conducted using electrophysiological techniques on whole animals. However, the discovery of genes encoding the family of human olfactory receptors (ORs) paved the way for the development of a range of cellular assays, primarily used to deorphan ORs from mammals and insects. These assays have greatly advanced our knowledge of the molecular basis of olfaction, however, while there is currently good agreement on vertebrate and nematode olfactory signalling cascades, debate still surrounds the signalling mechanisms in insects. The inherent specificity and sensitivity of ORs makes them prime candidates as biological detectors of volatile ligands within biosensor devices, which have many potential applications. In the previous decade, researchers have investigated various technologies for transducing OR:ligand interactions into a readable format and thereby produce an olfactory biosensor (or bioelectronic nose) that maintains the discriminating power of the ORs in vivo. Here we review and compare the molecular mechanisms of olfaction in vertebrates and invertebrates, and also summarise the assay technologies utilising sub-tissue level sensing elements (cells and cell extracts), which have been applied to OR deorphanization and biosensor research. Although there are currently no commercial, "field-ready" olfactory biosensors of the kind discussed here, there have been several technological proof-of-concept studies suggesting that we will see their emergence within the next decade.

  10. Spontaneous olfactory receptor neuron activity determines follower cell response properties

    PubMed Central

    Joseph, Joby; Dunn, Felice A.; Stopfer, Mark

    2012-01-01

    Noisy or spontaneous activity is common in neural systems and poses a challenge to detecting and discriminating signals. Here we use the locust to answer fundamental questions about noise in the olfactory system: Where does spontaneous activity originate? How is this activity propagated or reduced throughout multiple stages of neural processing? What mechanisms favor the detection of signals despite the presence of spontaneous activity? We found that spontaneous activity long observed in the secondary projection neurons (PNs) originates almost entirely from the primary olfactory receptor neurons (ORNs) rather than from spontaneous circuit interactions in the antennal lobe, and that spontaneous activity in ORNs tonically depolarizes the resting membrane potentials of their target PNs and local neurons (LNs), and indirectly tonically depolarizes tertiary Kenyon cells (KCs). However, because these neurons have different response thresholds, in the absence of odor stimulation, ORNs and PNs display a high spontaneous firing rate but KCs are nearly silent. Finally, we used a simulation of the olfactory network to show that discrimination of signal and noise in the KCs is best when threshold levels are set so that baseline activity in PNs persists. Our results show how the olfactory system benefits from making a signal detection decision after a point of maximal information convergence, e.g., after KCs pool inputs from many PNs. PMID:22357872

  11. Penguins reduced olfactory receptor genes common to other waterbirds

    PubMed Central

    Lu, Qin; Wang, Kai; Lei, Fumin; Yu, Dan; Zhao, Huabin

    2016-01-01

    The sense of smell, or olfaction, is fundamental in the life of animals. However, penguins (Aves: Sphenisciformes) possess relatively small olfactory bulbs compared with most other waterbirds such as Procellariiformes and Gaviiformes. To test whether penguins have a reduced reliance on olfaction, we analyzed the draft genome sequences of the two penguins, which diverged at the origin of the order Sphenisciformes; we also examined six closely related species with available genomes, and identified 29 one-to-one orthologous olfactory receptor genes (i.e. ORs) that are putatively functionally conserved and important across the eight birds. To survey the 29 one-to-one orthologous ORs in penguins and their relatives, we newly generated 34 sequences that are missing from the draft genomes. Through the analysis of totaling 378 OR sequences, we found that, of these functionally important ORs common to other waterbirds, penguins have a significantly greater percentage of OR pseudogenes than other waterbirds, suggesting a reduction of olfactory capability. The penguin-specific reduction of olfactory capability arose in the common ancestor of penguins between 23 and 60 Ma, which may have resulted from the aquatic specializations for underwater vision. Our study provides genetic evidence for a possible reduction of reliance on olfaction in penguins. PMID:27527385

  12. Penguins reduced olfactory receptor genes common to other waterbirds.

    PubMed

    Lu, Qin; Wang, Kai; Lei, Fumin; Yu, Dan; Zhao, Huabin

    2016-08-16

    The sense of smell, or olfaction, is fundamental in the life of animals. However, penguins (Aves: Sphenisciformes) possess relatively small olfactory bulbs compared with most other waterbirds such as Procellariiformes and Gaviiformes. To test whether penguins have a reduced reliance on olfaction, we analyzed the draft genome sequences of the two penguins, which diverged at the origin of the order Sphenisciformes; we also examined six closely related species with available genomes, and identified 29 one-to-one orthologous olfactory receptor genes (i.e. ORs) that are putatively functionally conserved and important across the eight birds. To survey the 29 one-to-one orthologous ORs in penguins and their relatives, we newly generated 34 sequences that are missing from the draft genomes. Through the analysis of totaling 378 OR sequences, we found that, of these functionally important ORs common to other waterbirds, penguins have a significantly greater percentage of OR pseudogenes than other waterbirds, suggesting a reduction of olfactory capability. The penguin-specific reduction of olfactory capability arose in the common ancestor of penguins between 23 and 60 Ma, which may have resulted from the aquatic specializations for underwater vision. Our study provides genetic evidence for a possible reduction of reliance on olfaction in penguins.

  13. Penguins reduced olfactory receptor genes common to other waterbirds.

    PubMed

    Lu, Qin; Wang, Kai; Lei, Fumin; Yu, Dan; Zhao, Huabin

    2016-01-01

    The sense of smell, or olfaction, is fundamental in the life of animals. However, penguins (Aves: Sphenisciformes) possess relatively small olfactory bulbs compared with most other waterbirds such as Procellariiformes and Gaviiformes. To test whether penguins have a reduced reliance on olfaction, we analyzed the draft genome sequences of the two penguins, which diverged at the origin of the order Sphenisciformes; we also examined six closely related species with available genomes, and identified 29 one-to-one orthologous olfactory receptor genes (i.e. ORs) that are putatively functionally conserved and important across the eight birds. To survey the 29 one-to-one orthologous ORs in penguins and their relatives, we newly generated 34 sequences that are missing from the draft genomes. Through the analysis of totaling 378 OR sequences, we found that, of these functionally important ORs common to other waterbirds, penguins have a significantly greater percentage of OR pseudogenes than other waterbirds, suggesting a reduction of olfactory capability. The penguin-specific reduction of olfactory capability arose in the common ancestor of penguins between 23 and 60 Ma, which may have resulted from the aquatic specializations for underwater vision. Our study provides genetic evidence for a possible reduction of reliance on olfaction in penguins. PMID:27527385

  14. Anterograde fluorescent labeling of olfactory receptor neurons by Procion and Lucifer dyes.

    PubMed

    Suzuki, N

    1984-10-01

    The repetitive irrigation of lamprey and frog olfactory epithelia with the fluorescent dyes Procion yellow MX4R and Lucifer yellow VS, induced the uptake of these dyes by olfactory receptor neurons, resulting in selective staining of the latter. The stained receptors retained the dyes within their cytoplasm during cell dissociation procedures, which proved these fluorescent dyes to be useful cell markers for the identification of olfactory receptor neurons in dissociated cell mixtures.

  15. Molecular Characterization of the Aphis gossypii Olfactory Receptor Gene Families

    PubMed Central

    Walker, William B.; Li, Jianhong; Wang, Guirong

    2014-01-01

    The cotton aphid, Aphis gossypii Glover, is a polyphagous pest that inflicts great damage to cotton yields worldwide. Antennal olfaction, which is extremely important for insect survival, mediates key behaviors such as host preference, mate choice, and oviposition site selection. In insects, odor detection is mediated by odorant receptors (ORs) and ionotropic receptors (IRs), which ensure the specificity of the olfactory sensory neuron responses. In this study, our aim is to identify chemosensory receptors in the cotton aphid genome, as a means to uncover olfactory encoding of the polyphagous feeding habits as well as to aid the discovery of new targets for behavioral interference. We identified a total of 45 candidate ORs and 14 IRs in the cotton aphid genome. Among the candidate AgoORs, 9 are apparent pseudogenes, while 19 can be clustered with ORs from the pea aphid, forming 16 AgoOR/ApOR orthologous subgroups. Among the candidate IRs, we identified homologs of the two highly conserved co-receptors IR8a and IR25a; no AgoIR retain the complete glutamic acid binding domain, suggesting that putative AgoIRs bind different ligands. Our results provide the necessary information for functional characterization of the chemosensory receptors of A. gossypii, with potential for new or refined applications of semiochemicals-based control of this pest insect. PMID:24971460

  16. Molecular characterization of the Aphis gossypii olfactory receptor gene families.

    PubMed

    Cao, Depan; Liu, Yang; Walker, William B; Li, Jianhong; Wang, Guirong

    2014-01-01

    The cotton aphid, Aphis gossypii Glover, is a polyphagous pest that inflicts great damage to cotton yields worldwide. Antennal olfaction, which is extremely important for insect survival, mediates key behaviors such as host preference, mate choice, and oviposition site selection. In insects, odor detection is mediated by odorant receptors (ORs) and ionotropic receptors (IRs), which ensure the specificity of the olfactory sensory neuron responses. In this study, our aim is to identify chemosensory receptors in the cotton aphid genome, as a means to uncover olfactory encoding of the polyphagous feeding habits as well as to aid the discovery of new targets for behavioral interference. We identified a total of 45 candidate ORs and 14 IRs in the cotton aphid genome. Among the candidate AgoORs, 9 are apparent pseudogenes, while 19 can be clustered with ORs from the pea aphid, forming 16 AgoOR/ApOR orthologous subgroups. Among the candidate IRs, we identified homologs of the two highly conserved co-receptors IR8a and IR25a; no AgoIR retain the complete glutamic acid binding domain, suggesting that putative AgoIRs bind different ligands. Our results provide the necessary information for functional characterization of the chemosensory receptors of A. gossypii, with potential for new or refined applications of semiochemicals-based control of this pest insect. PMID:24971460

  17. Neuropeptide S facilitates mice olfactory function through activation of cognate receptor-expressing neurons in the olfactory cortex.

    PubMed

    Shao, Yu-Feng; Zhao, Peng; Dong, Chao-Yu; Li, Jing; Kong, Xiang-Pan; Wang, Hai-Liang; Dai, Li-Rong; Hou, Yi-Ping

    2013-01-01

    Neuropeptide S (NPS) is a newly identified neuromodulator located in the brainstem and regulates various biological functions by selectively activating the NPS receptors (NPSR). High level expression of NPSR mRNA in the olfactory cortex suggests that NPS-NPSR system might be involved in the regulation of olfactory function. The present study was undertaken to investigate the effects of intracerebroventricular (i.c.v.) injection of NPS or co-injection of NPSR antagonist on the olfactory behaviors, food intake, and c-Fos expression in olfactory cortex in mice. In addition, dual-immunofluorescence was employed to identify NPS-induced Fos immunereactive (-ir) neurons that also bear NPSR. NPS (0.1-1 nmol) i.c.v. injection significantly reduced the latency to find the buried food, and increased olfactory differentiation of different odors and the total sniffing time spent in olfactory habituation/dishabituation tasks. NPS facilitated olfactory ability most at the dose of 0.5 nmol, which could be blocked by co-injection of 40 nmol NPSR antagonist [D-Val(5)]NPS. NPS administration dose-dependently inhibited food intake in fasted mice. Ex-vivo c-Fos and NPSR immunohistochemistry in the olfactory cortex revealed that, as compared with vehicle-treated mice, NPS markedly enhanced c-Fos expression in the anterior olfactory nucleus (AON), piriform cortex (Pir), ventral tenia tecta (VTT), the anterior cortical amygdaloid nucleus (ACo) and lateral entorhinal cortex (LEnt). The percentage of Fos-ir neurons that also express NPSR were 88.5% and 98.1% in the AON and Pir, respectively. The present findings demonstrated that NPS, via selective activation of the neurons bearing NPSR in the olfactory cortex, facilitates olfactory function in mice.

  18. Temporal coding of odor mixtures in an olfactory receptor neuron

    PubMed Central

    Su, Chih-Ying; Martelli, Carlotta; Emonet, Thierry; Carlson, John R.

    2011-01-01

    Most natural odors are mixtures and often elicit percepts distinct from those elicited by their constituents. This emergence of a unique odor quality has long been attributed to central processing. Here we show that sophisticated integration of olfactory information begins in olfactory receptor neurons (ORNs) in Drosophila. Odor mixtures are encoded in the temporal dynamics as well as in the magnitudes of ORN responses. ORNs can respond to an inhibitory odorant with different durations depending on the level of background excitation. ORNs respond to mixtures with distinctive temporal dynamics that reflect the physicochemical properties of the constituent odorants. The insect repellent DEET (N,N-diethyl-m-toluamide), which attenuates odor responses of multiple ORNs, differs from an ORN-specific inhibitor in its effects on temporal dynamics. Our analysis reveals a means by which integration of information from odor mixtures begins in ORNs and provides insight into the contribution of inhibitory stimuli to sensory coding. PMID:21383179

  19. Beyond Modeling: All-Atom Olfactory Receptor Model Simulations

    PubMed Central

    Lai, Peter C.; Crasto, Chiquito J.

    2012-01-01

    Olfactory receptors (ORs) are a type of GTP-binding protein-coupled receptor (GPCR). These receptors are responsible for mediating the sense of smell through their interaction with odor ligands. OR-odorant interactions marks the first step in the process that leads to olfaction. Computational studies on model OR structures can generate focused and novel hypotheses for further bench investigation by providing a view of these interactions at the molecular level beyond inferences that are drawn merely from static docking. Here we have shown the specific advantages of simulating the dynamic environment associated with OR-odorant interactions. We present a rigorous protocol which ranges from the creation of a computationally derived model of an olfactory receptor to simulating the interactions between an OR and an odorant molecule. Given the ubiquitous occurrence of GPCRs in the membranes of cells, we anticipate that our OR-developed methodology will serve as a model for the computational structural biology of all GPCRs. PMID:22563330

  20. High potency olfactory receptor agonists discovered by virtual high-throughput screening: molecular probes for receptor structure and olfactory function

    PubMed Central

    Triballeau, Nicolas; Van Name, Eric; Laslier, Guillaume; Cai, Diana; Paillard, Guillaume; Sorensen, Peter W.; Hoffmann, Rémy; Bertrand, Hugues-Olivier; Ngai, John; Acher, Francine C.

    2008-01-01

    The detection and discrimination of diverse chemical structures by the vertebrate olfactory system is accomplished by the recognition of odorous ligands by their cognate receptors. In the present study we used a computational high-throughput screening strategy to discover novel high affinity agonists of an olfactory G protein-coupled receptor tuned to recognize amino acid ligands. Functional testing of the top candidates validated several agonists with potencies higher than any of the receptor’s known natural ligands. Computational modeling revealed molecular interactions involved in ligand recognition by this receptor, and further highlighted interactions that have been conserved in evolutionarily divergent amino acid receptors. Significantly, the top compounds display robust activities as odorants in vivo, and include a natural product that may be used to signal the presence of bacteria in the aquatic environment. Our virtual screening approach should be applicable to the identification of new bioactive molecules for probing the structure of chemosensory receptors and the function of chemosensory systems in vivo. PMID:19081373

  1. SNP genotypes of olfactory receptor genes associated with olfactory ability in German Shepherd dogs.

    PubMed

    Yang, M; Geng, G-J; Zhang, W; Cui, L; Zhang, H-X; Zheng, J-L

    2016-04-01

    To find out the relationship between SNP genotypes of canine olfactory receptor genes and olfactory ability, 28 males and 20 females from German Shepherd dogs in police service were scored by odor detection tests and analyzed using the Beckman GenomeLab SNPstream. The representative 22 SNP loci from the exonic regions of 12 olfactory receptor genes were investigated, and three kinds of odor (human, ice drug and trinitrotoluene) were detected. The results showed that the SNP genotypes at the OR10H1-like:c.632C>T, OR10H1-like:c.770A>T, OR2K2-like:c.518G>A, OR4C11-like:c.511T>G and OR4C11-like:c.692G>A loci had a statistically significant effect on the scenting abilities (P < 0.001). The kind of odor influenced the performances of the dogs (P < 0.001). In addition, there were interactions between genotype and the kind of odor at the following loci: OR10H1-like:c.632C>T, OR10H1-like:c.770A>T, OR4C11-like:c.511T>G and OR4C11-like:c.692G>A (P < 0.001). The dogs with genotype CC at the OR10H1-like:c.632C>T, genotype AA at the OR10H1-like:c.770A>T, genotype TT at the OR4C11-like:c.511T>G and genotype GG at the OR4C11-like:c.692G>A loci did better at detecting the ice drug. We concluded that there was linkage between certain SNP genotypes and the olfactory ability of dogs and that SNP genotypes might be useful in determining dogs' scenting potential.

  2. Molecular Cooperativity Governs Diverse and Monoallelic Olfactory Receptor Expression

    NASA Astrophysics Data System (ADS)

    Xing, Jianhua; Tian, Xiaojun; Zhang, Hang; Sannerud, Jens

    Multiple-objective optimization is common in biological systems. In the mammalian olfactory system, each sensory neuron stochastically expresses only one out of up to thousands of olfactory receptor (OR) gene alleles; at organism level the types of expressed ORs need to be maximized. The molecular mechanism of this Nobel-Prize winning puzzle remains unresolved after decades of extensive studies. Existing models focus only on monoallele activation, and cannot explain recent observations in mutants, especially the reduced global diversity of expressed ORs in G9a/GLP knockouts. In this work we integrated existing information on OR expression, and proposed an evolutionarily optimized three-layer regulation mechanism, which includes zonal segregation, epigenetic and enhancer competition coupled to a negative feedback loop. This model not only recapitulates monoallelic OR expression, but also elucidates how the olfactory system maximizes and maintains the diversity of OR expression. The model is validated by several experimental results, and particularly underscores cooperativity and synergy as a general design principle of multi-objective optimization in biology. The work is supported by the NIGMS/DMS Mathematical Biology program.

  3. Differential Contributions of Olfactory Receptor Neurons in a Drosophila Olfactory Circuit.

    PubMed

    Newquist, Gunnar; Novenschi, Alexandra; Kohler, Donovan; Mathew, Dennis

    2016-01-01

    The ability of an animal to detect, discriminate, and respond to odors depends on the functions of its olfactory receptor neurons (ORNs). The extent to which each ORN, upon activation, contributes to chemotaxis is not well understood. We hypothesized that strong activation of each ORN elicits a different behavioral response in the Drosophila melanogaster larva by differentially affecting the composition of its navigational behavior. To test this hypothesis, we exposed Drosophila larvae to specific odorants to analyze the effect of individual ORN activity on chemotaxis. We used two different behavioral paradigms to analyze the chemotaxis response of larvae to odorants. When tested with five different odorants that elicit strong physiological responses from single ORNs, larval behavioral responses toward each odorant differed in the strength of attraction as well as in the composition of discrete navigational elements, such as runs and turns. Further, behavioral responses to odorants did not correlate with either the strength of odor gradients tested or the sensitivity of each ORN to its cognate odorant. Finally, we provide evidence that wild-type larvae with all ORNs intact exhibit higher behavioral variance than mutant larvae that have only a single pair of functional ORNs. We conclude that individual ORNs contribute differently to the olfactory circuit that instructs chemotactic responses. Our results, along with recent studies from other groups, suggest that ORNs are functionally nonequivalent units. These results have implications for understanding peripheral odor coding. PMID:27570823

  4. Differential Contributions of Olfactory Receptor Neurons in a Drosophila Olfactory Circuit

    PubMed Central

    Newquist, Gunnar; Novenschi, Alexandra; Kohler, Donovan

    2016-01-01

    Abstract The ability of an animal to detect, discriminate, and respond to odors depends on the functions of its olfactory receptor neurons (ORNs). The extent to which each ORN, upon activation, contributes to chemotaxis is not well understood. We hypothesized that strong activation of each ORN elicits a different behavioral response in the Drosophila melanogaster larva by differentially affecting the composition of its navigational behavior. To test this hypothesis, we exposed Drosophila larvae to specific odorants to analyze the effect of individual ORN activity on chemotaxis. We used two different behavioral paradigms to analyze the chemotaxis response of larvae to odorants. When tested with five different odorants that elicit strong physiological responses from single ORNs, larval behavioral responses toward each odorant differed in the strength of attraction as well as in the composition of discrete navigational elements, such as runs and turns. Further, behavioral responses to odorants did not correlate with either the strength of odor gradients tested or the sensitivity of each ORN to its cognate odorant. Finally, we provide evidence that wild-type larvae with all ORNs intact exhibit higher behavioral variance than mutant larvae that have only a single pair of functional ORNs. We conclude that individual ORNs contribute differently to the olfactory circuit that instructs chemotactic responses. Our results, along with recent studies from other groups, suggest that ORNs are functionally nonequivalent units. These results have implications for understanding peripheral odor coding. PMID:27570823

  5. Loss of Olfactory Receptor Function in Hominin Evolution

    PubMed Central

    Hughes, Graham M.; Teeling, Emma C.; Higgins, Desmond G.

    2014-01-01

    The mammalian sense of smell is governed by the largest gene family, which encodes the olfactory receptors (ORs). The gain and loss of OR genes is typically correlated with adaptations to various ecological niches. Modern humans have 853 OR genes but 55% of these have lost their function. Here we show evidence of additional OR loss of function in the Neanderthal and Denisovan hominin genomes using comparative genomic methodologies. Ten Neanderthal and 8 Denisovan ORs show evidence of loss of function that differ from the reference modern human OR genome. Some of these losses are also present in a subset of modern humans, while some are unique to each lineage. Morphological changes in the cranium of Neanderthals suggest different sensory arrangements to that of modern humans. We identify differences in functional olfactory receptor genes among modern humans, Neanderthals and Denisovans, suggesting varied loss of function across all three taxa and we highlight the utility of using genomic information to elucidate the sensory niches of extinct species. PMID:24392153

  6. Loss of olfactory receptor function in hominin evolution.

    PubMed

    Hughes, Graham M; Teeling, Emma C; Higgins, Desmond G

    2014-01-01

    The mammalian sense of smell is governed by the largest gene family, which encodes the olfactory receptors (ORs). The gain and loss of OR genes is typically correlated with adaptations to various ecological niches. Modern humans have 853 OR genes but 55% of these have lost their function. Here we show evidence of additional OR loss of function in the Neanderthal and Denisovan hominin genomes using comparative genomic methodologies. Ten Neanderthal and 8 Denisovan ORs show evidence of loss of function that differ from the reference modern human OR genome. Some of these losses are also present in a subset of modern humans, while some are unique to each lineage. Morphological changes in the cranium of Neanderthals suggest different sensory arrangements to that of modern humans. We identify differences in functional olfactory receptor genes among modern humans, Neanderthals and Denisovans, suggesting varied loss of function across all three taxa and we highlight the utility of using genomic information to elucidate the sensory niches of extinct species.

  7. Monoterpene (-)-citronellal affects hepatocarcinoma cell signaling via an olfactory receptor.

    PubMed

    Maßberg, Désirée; Simon, Annika; Häussinger, Dieter; Keitel, Verena; Gisselmann, Günter; Conrad, Heike; Hatt, Hanns

    2015-01-15

    Terpenes are the major constituents of essential oils in plants. In recent years, terpenes have become of clinical relevance due to their ability to suppress cancer development. Their effect on cellular proliferation has made them promising agents in the prevention or treatment of many types of cancer. In the present study, a subset of different monoterpenes was investigated for their molecular effects on the hepatocellular carcinoma cell line Huh7. Using fluorometric calcium imaging, acyclic monoterpene (-)-citronellal was found to induce transient Ca(2+) signals in Huh7 cells by activating a cAMP-dependent signaling pathway. Moreover, we detected the (-)-citronellal-activated human olfactory receptor OR1A2 at the mRNA and protein levels and demonstrated its potential involvement in (-)-citronellal-induced calcium signaling in Huh7 cells. Furthermore, activation of OR1A2 results in phosphorylation of p38 MAPK and reduced cell proliferation, indicating an effect on hepatocellular carcinoma progression. Here, we provide for the first time data on the molecular mechanism evoked by (-)-citronellal in human hepatocellular carcinoma cells. The identified olfactory receptor could serve as a potential therapeutic target for cancer diagnosis and treatment.

  8. Specific repertoire of olfactory receptor genes in the male germ cells of several mammalian species

    SciTech Connect

    Vanderhaeghen, P.; Schurmans, S.; Vassart, G.; Parmentier, M.

    1997-02-01

    Olfactory receptors constitute the largest family among G protein-coupled receptors, with up to 1000 members expected. We have previously shown that genes belonging to this family were expressed in the male germ line from both dog and human. We have subsequently demonstrated the presence of one of the corresponding olfactory receptor proteins during dog spermatogenesis and in mature sperm cells. In this study, we investigated whether the unexpected pattern of expression of olfactory receptors in the male germ line was conserved in other mammalian species. Using reverse transcription-PCR with primers specific for the olfactory receptor gene family, about 20 olfactory receptor cDNA fragments were cloned from the testis of each mammalian species tested. As a whole, they displayed no sequence specificity compared to other olfactory receptors, but highly homologous, possibly orthologous, genes were amplified from different species. Finally, their pattern of expression, as determined by RNase protection assay, revealed that many but not all of these receptors were expressed predominantly in testis. The male germ line from each mammalian species tested is thus characterized by a specific repertoire of olfactory receptors, which display a pattern of expression suggestive of their potential implication in the control of sperm maturation, migration, or fertilization. 34 refs., 4 figs., 1 tab.

  9. Identification and functional analysis of olfactory receptor family reveal unusual characteristics of the olfactory system in the migratory locust.

    PubMed

    Wang, Zhifeng; Yang, Pengcheng; Chen, Dafeng; Jiang, Feng; Li, Yan; Wang, Xianhui; Kang, Le

    2015-11-01

    Locusts represent the excellent model of insect olfaction because the animals are equipped with an unusual olfactory system and display remarkable density-dependent olfactory plasticity. However, information regarding receptor molecules involved in the olfactory perception of locusts is very limited. On the basis of genome sequence and antennal transcriptome of the migratory locust, we conduct the identification and functional analysis of two olfactory receptor families: odorant receptors (ORs) and ionotropic receptors (IRs). In the migratory locust, there is an expansion of OR family (142 ORs) while distinctly lower number of IR genes (32 IRs) compared to the repertoires of other insects. The number of the locust OR genes is much less than that of glomeruli in antennal lobe, challenging the general principle of the "one glomerulus-one receptor" observed in other insects. Most OR genes are found in tandem arrays, forming two large lineage-specific subfamilies in the phylogenetic tree. The "divergent IR" subfamily displays a significant contraction, and most of the IRs belong to the "antennal IR" subfamily in the locust. Most ORs/IRs have olfactory-specific expression while some broadly- or internal-expressed members are also found. Differing from holometabolous insects, the migratory locust contains very similar expression profiles of ORs/IRs between nymph and adult stages. RNA interference and behavioral assays indicate that an OR-based signaling pathway, not IR-based, mediates the attraction of locusts to aggregation pheromones. These discoveries provide insights into the unusual olfactory system of locusts and enhance our understanding of the evolution of insect olfaction. PMID:26265180

  10. Identification and functional analysis of olfactory receptor family reveal unusual characteristics of the olfactory system in the migratory locust.

    PubMed

    Wang, Zhifeng; Yang, Pengcheng; Chen, Dafeng; Jiang, Feng; Li, Yan; Wang, Xianhui; Kang, Le

    2015-11-01

    Locusts represent the excellent model of insect olfaction because the animals are equipped with an unusual olfactory system and display remarkable density-dependent olfactory plasticity. However, information regarding receptor molecules involved in the olfactory perception of locusts is very limited. On the basis of genome sequence and antennal transcriptome of the migratory locust, we conduct the identification and functional analysis of two olfactory receptor families: odorant receptors (ORs) and ionotropic receptors (IRs). In the migratory locust, there is an expansion of OR family (142 ORs) while distinctly lower number of IR genes (32 IRs) compared to the repertoires of other insects. The number of the locust OR genes is much less than that of glomeruli in antennal lobe, challenging the general principle of the "one glomerulus-one receptor" observed in other insects. Most OR genes are found in tandem arrays, forming two large lineage-specific subfamilies in the phylogenetic tree. The "divergent IR" subfamily displays a significant contraction, and most of the IRs belong to the "antennal IR" subfamily in the locust. Most ORs/IRs have olfactory-specific expression while some broadly- or internal-expressed members are also found. Differing from holometabolous insects, the migratory locust contains very similar expression profiles of ORs/IRs between nymph and adult stages. RNA interference and behavioral assays indicate that an OR-based signaling pathway, not IR-based, mediates the attraction of locusts to aggregation pheromones. These discoveries provide insights into the unusual olfactory system of locusts and enhance our understanding of the evolution of insect olfaction.

  11. Inhibition of Olfactory Receptor Neuron Input to Olfactory Bulb Glomeruli Mediated by Suppression of Presynaptic Calcium Influx

    PubMed Central

    Wachowiak, Matt; McGann, John P.; Heyward, Philip M.; Shao, Zuoyi; Puche, Adam C.; Shipley, Michael T.

    2005-01-01

    We investigated the cellular mechanism underlying presynaptic regulation of olfactory receptor neuron (ORN) input to the mouse olfactory bulb using optical-imaging techniques that selectively report activity in the ORN pre-synaptic terminal. First, we loaded ORNs with calcium-sensitive dye and imaged stimulus-evoked calcium influx in a slice preparation. Single olfactory nerve shocks evoked rapid fluorescence increases that were largely blocked by the N-type calcium channel blocker ω-conotoxin GVIA. Paired shocks revealed a long-lasting suppression of calcium influx with ~40% suppression at 400-ms interstimulus intervals and a recovery time constant of ~450 ms. Blocking activation of postsynaptic olfactory bulb neurons with APV/CNQX reduced this suppression. The GABAB receptor agonist baclofen inhibited calcium influx, whereas GABAB antagonists reduced paired-pulse suppression without affecting the response to the conditioning pulse. We also imaged transmitter release directly using a mouse line that expresses synaptopHluorin selectively in ORNs. We found that the relationship between calcium influx and transmitter release was superlinear and that paired-pulse suppression of transmitter release was reduced, but not eliminated, by APV/CNQX and GABAB antagonists. These results demonstrate that primary olfactory input to the CNS can be presynaptically regulated by GABAergic interneurons and show that one major intracellular pathway for this regulation is via the suppression of calcium influx through N-type calcium channels in the pre-synaptic terminal. This mechanism is unique among primary sensory afferents. PMID:15917320

  12. Olfactory receptor for prostaglandin F2α mediates male fish courtship behavior.

    PubMed

    Yabuki, Yoichi; Koide, Tetsuya; Miyasaka, Nobuhiko; Wakisaka, Noriko; Masuda, Miwa; Ohkura, Masamichi; Nakai, Junichi; Tsuge, Kyoshiro; Tsuchiya, Soken; Sugimoto, Yukihiko; Yoshihara, Yoshihiro

    2016-07-01

    Pheromones play vital roles for survival and reproduction in various organisms. In many fishes, prostaglandin F2α acts not only as a female reproductive hormone, facilitating ovulation and spawning, but also as a sex pheromone inducing male reproductive behaviors. Here, we unravel the molecular and neural circuit mechanisms underlying the pheromonal action of prostaglandin F2α in zebrafish. Prostaglandin F2α specifically activates two olfactory receptors with different sensitivities and expression in distinct populations of ciliated olfactory sensory neurons. Pheromone information is then transmitted to two ventromedial glomeruli in the olfactory bulb and further to four regions in higher olfactory centers. Mutant male zebrafish deficient in the high-affinity receptor exhibit loss of attractive response to prostaglandin F2α and impairment of courtship behaviors toward female fish. These findings demonstrate the functional significance and activation of selective neural circuitry for the sex pheromone prostaglandin F2α and its cognate olfactory receptor in fish reproductive behavior. PMID:27239939

  13. Single-cell transcriptomics reveals receptor transformations during olfactory neurogenesis.

    PubMed

    Hanchate, Naresh K; Kondoh, Kunio; Lu, Zhonghua; Kuang, Donghui; Ye, Xiaolan; Qiu, Xiaojie; Pachter, Lior; Trapnell, Cole; Buck, Linda B

    2015-12-01

    The sense of smell allows chemicals to be perceived as diverse scents. We used single-neuron RNA sequencing to explore the developmental mechanisms that shape this ability as nasal olfactory neurons mature in mice. Most mature neurons expressed only one of the ~1000 odorant receptor genes (Olfrs) available, and at a high level. However, many immature neurons expressed low levels of multiple Olfrs. Coexpressed Olfrs localized to overlapping zones of the nasal epithelium, suggesting regional biases, but not to single genomic loci. A single immature neuron could express Olfrs from up to seven different chromosomes. The mature state in which expression of Olfr genes is restricted to one per neuron emerges over a developmental progression that appears to be independent of neuronal activity involving sensory transduction molecules.

  14. The number of functional olfactory receptor genes and the relative size of olfactory brain structures are poor predictors of olfactory discrimination performance with enantiomers.

    PubMed

    Laska, Matthias; Genzel, Daria; Wieser, Alexandra

    2005-02-01

    The ability of four squirrel monkeys and three pigtail macaques to distinguish between nine enantiomeric odor pairs sharing an isopropenyl group at the chiral center was investigated in terms of a conditioning paradigm. All animals from both species were able to discriminate between the optical isomers of limonene, carvone, dihydrocarvone, dihydrocarveole and dihydrocarvyl acetate, whereas they failed to distinguish between the (+)- and (-)-forms of perillaaldehyde and limonene oxide. The pigtail macaques, but not the squirrel monkeys, also discriminated between the antipodes of perillaalcohol and isopulegol. A comparison of the across-task patterns of discrimination performance shows a high degree of similarity among the two primate species and also between these nonhuman primates and human subjects tested in an earlier study on the same tasks. These findings suggest that between-species comparisons of the relative size of olfactory brain structures or of the number of functional olfactory receptor genes are poor predictors of olfactory discrimination performance with enantiomers. PMID:15703336

  15. Retrograde labeling and fine structure of olfactory receptor neurons in cat sharks.

    PubMed

    Niikura, Rieko; Nakatani, Kei

    2012-08-01

    Ciliated and microvillar olfactory receptor cells have been reported in many fish species, including teleosts and elasmobranchs. Morphological studies have suggested that microvillar cells are the only olfactory receptor cells in the elasmobranchs; however, there is no direct evidence for this hypothesis. Here we used a cat shark (Scyliorhinus torazame) to determine the cell type of the olfactory receptor cells in elasmobranchs. Retrograde labeling with a fluorescent dye, Dil, labeled only cells in the second layer from the surface of the olfactory epithelium, suggesting that ciliated cells located in the surface layer are not olfactory receptor cells. In addition, electron microscopic observation revealed that the labeled cells in the second layer have a thin dendritic knob extending from the cell body to the free surface of the epithelium. A part of the dendritic knob facing the mucous layer did not have ciliary structures. These results provide evidence that the aciliate cells are the only olfactory receptor cells in the cat shark olfactory organ. PMID:22873803

  16. Analysis of the goldfish Carassius auratus olfactory epithelium transcriptome reveals the presence of numerous non-olfactory GPCR and putative receptors for progestin pheromones

    PubMed Central

    Kolmakov, Nikolay N; Kube, Michael; Reinhardt, Richard; Canario, Adelino VM

    2008-01-01

    Background The goldfish (Carassius auratus) uses steroids and prostaglandins as pheromone cues at different stages of the reproductive cycle to facilitate spawning synchronization. Steroid progestin pheromone binding has been detected in goldfish olfactory membranes but the receptors responsible for this specific binding remain unknown. In order to shed some light on the olfactory epithelium transcriptome and search for possible receptor candidates a large set of EST from this tissue were analysed and compared to and combined with a similar zebrafish (Danio rerio) resource. Results We generated 4,797 high quality sequences from a normalized cDNA library of the goldfish olfactory epithelium, which were clustered in 3,879 unique sequences, grouped in 668 contigs and 3,211 singletons. BLASTX searches produced 3,243 significant (E-value < e-10) hits and Gene Ontology (GO) analysis annotated a further 1,223 of these genes (37.7%). Comparative analysis with zebrafish olfactory epithelium ESTs revealed 1,088 identical unigenes. The transcriptome size of both species was estimated at about 16,400 unigenes, based on the proportion of genes identified involved in Glucose Metabolic Process. Of 124 G-protein coupled receptors identified in the olfactory epithelium of both species, 56 were olfactory receptors. Beta and gamma membrane progestin receptors were also isolated by subcloning of RT-PCR products from both species and an olfactory epithelium specific splice form identified. Conclusion The high similarity between the goldfish and zebrafish olfactory systems allowed the creation of a 'cyprinid' olfactory epithelium library estimated to represent circa 70% of the transcriptome. These results are an important resource for the identification of components of signalling pathways involved in olfaction as well as putative targets for pharmacological and histochemical studies. The possible function of the receptors identified in the olfactory system is described. Moreover, the

  17. Olfactory receptor and neural pathway responsible for highly selective sensing of musk odors.

    PubMed

    Shirasu, Mika; Yoshikawa, Keiichi; Takai, Yoshiki; Nakashima, Ai; Takeuchi, Haruki; Sakano, Hitoshi; Touhara, Kazushige

    2014-01-01

    Musk odorants are used widely in cosmetic industries because of their fascinating animalic scent. However, how this aroma is perceived in the mammalian olfactory system remains a great mystery. Here, we show that muscone, one musk odor secreted by various animals from stink glands, activates a few glomeruli clustered in a neuroanatomically unique anteromedial olfactory bulb. The muscone-responsive glomeruli are highly specific to macrocyclic ketones; interestingly, other synthetic musk odorants with nitro or polycyclic moieties or ester bonds activate distinct but nearby glomeruli. Anterodorsal bulbar lesions cause muscone anosmia, suggesting that this region is involved in muscone perception. Finally, we identified the mouse olfactory receptor, MOR215-1, that was a specific muscone receptor expressed by neurons innervating the muscone-responsive anteromedial glomeruli and also the human muscone receptor, OR5AN1. The current study documents the olfactory neural pathway in mice that senses and transmits musk signals from receptor to brain.

  18. Computational Approaches for Decoding Select Odorant-Olfactory Receptor Interactions Using Mini-Virtual Screening.

    PubMed

    Harini, K; Sowdhamini, Ramanathan

    2015-01-01

    Olfactory receptors (ORs) belong to the class A G-Protein Coupled Receptor superfamily of proteins. Unlike G-Protein Coupled Receptors, ORs exhibit a combinatorial response to odors/ligands. ORs display an affinity towards a range of odor molecules rather than binding to a specific set of ligands and conversely a single odorant molecule may bind to a number of olfactory receptors with varying affinities. The diversity in odor recognition is linked to the highly variable transmembrane domains of these receptors. The purpose of this study is to decode the odor-olfactory receptor interactions using in silico docking studies. In this study, a ligand (odor molecules) dataset of 125 molecules was used to carry out in silico docking using the GLIDE docking tool (SCHRODINGER Inc Pvt LTD). Previous studies, with smaller datasets of ligands, have shown that orthologous olfactory receptors respond to similarly-tuned ligands, but are dramatically different in their efficacy and potency. Ligand docking results were applied on homologous pairs (with varying sequence identity) of ORs from human and mouse genomes and ligand binding residues and the ligand profile differed among such related olfactory receptor sequences. This study revealed that homologous sequences with high sequence identity need not bind to the same/ similar ligand with a given affinity. A ligand profile has been obtained for each of the 20 receptors in this analysis which will be useful for expression and mutation studies on these receptors.

  19. Computational Approaches for Decoding Select Odorant-Olfactory Receptor Interactions Using Mini-Virtual Screening

    PubMed Central

    Harini, K.; Sowdhamini, Ramanathan

    2015-01-01

    Olfactory receptors (ORs) belong to the class A G-Protein Coupled Receptor superfamily of proteins. Unlike G-Protein Coupled Receptors, ORs exhibit a combinatorial response to odors/ligands. ORs display an affinity towards a range of odor molecules rather than binding to a specific set of ligands and conversely a single odorant molecule may bind to a number of olfactory receptors with varying affinities. The diversity in odor recognition is linked to the highly variable transmembrane domains of these receptors. The purpose of this study is to decode the odor-olfactory receptor interactions using in silico docking studies. In this study, a ligand (odor molecules) dataset of 125 molecules was used to carry out in silico docking using the GLIDE docking tool (SCHRODINGER Inc Pvt LTD). Previous studies, with smaller datasets of ligands, have shown that orthologous olfactory receptors respond to similarly-tuned ligands, but are dramatically different in their efficacy and potency. Ligand docking results were applied on homologous pairs (with varying sequence identity) of ORs from human and mouse genomes and ligand binding residues and the ligand profile differed among such related olfactory receptor sequences. This study revealed that homologous sequences with high sequence identity need not bind to the same/ similar ligand with a given affinity. A ligand profile has been obtained for each of the 20 receptors in this analysis which will be useful for expression and mutation studies on these receptors. PMID:26221959

  20. Cloning and olfactory expression of progestin receptors in the Chinese black sleeper Bostrichthys sinensis.

    PubMed

    Zhang, Yu Ting; Liu, Dong Teng; Zhu, Yong; Chen, Shi Xi; Hong, Wan Shu

    2016-05-01

    Our previous studies suggested that 17α,20β-dihydroxy-4-pregnen-3-one (DHP), an oocyte maturation inducing progestin, also acts as a sex pheromone in Chinese black sleeper Bostrichthys sinensis, a fish species that inhabits intertidal zones and mates and spawns inside a muddy burrow. The electro-olfactogram response to DHP increased during the breeding season. In the present study, we cloned the cDNAs of the nine progestin receptors (pgr, paqr5, 6, 7(a, b), 8, 9, pgrmc1, 2) from B. sinensis, analyzed their tissue distribution, and determined the expression in the olfactory rosette during the reproductive cycle in female and male fish. The deduced amino acid sequences of the nine progestin receptors share high sequence identities with those of other fish species and relatively lower homology with their mammalian counterparts, and phylogenetic analyses classified the nine B. sinensis progestin receptors into their respective progestin receptor groups. Tissue distribution of B. sinensis progestin receptors showed differential expression patterns, but all these nine genes were expressed in the olfactory rosette. Interestingly, paqr5 mRNA was found in the intermediate and basal parts of the olfactory epithelium but not in the central core using in situ hybridization, and its expression level was the highest in the olfactory rosette among the tissues examined. These results suggested Paqr5 may have an important role for transmitting progestin signaling in the olfactory system. The expression levels of paqr7a and paqr7b, pgr and pgrmc2 mRNA peaked around the mid meiotic stage, and that of paqr8 peaked at late meiotic stage in the olfactory rosette in males, while the olfactory expression of paqr5 decreased gradually as spermatogenesis progressed. In contrast, the expression of the progestin receptors did not change significantly during the development of the ovary in the olfactory rosette in females, except that of pgr. Interestingly, the changes of paqr8 expression in

  1. Adult neurogenesis in the central olfactory pathway in the absence of receptor neuron turnover in Libinia emarginata

    PubMed Central

    Sullivan, Jeremy M.; Beltz, Barbara S.

    2009-01-01

    Life-long neurogenesis is a characteristic feature of the olfactory pathways of a phylogenetically diverse array of animals. In both vertebrates and invertebrates, the life-long addition of olfactory interneurons in the brain occurs in parallel with the continuous proliferation of olfactory receptor neurons in the olfactory organ. It has been proposed that these two processes are related functionally, with new olfactory interneurons being added to accommodate the new olfactory receptor neurons added in the periphery. While this has not been tested directly because the two processes are not readily separable, this question can be addressed in the olfactory pathway of the crab, Libinia emarginata. Unlike most decapod crustaceans, which moult and grow throughout life, L. emarginata has a terminal, maturational moult after which animals become anecdysic (stop moulting). Because the addition of new receptor neurons in crustaceans is associated with moulting, a comparison of neurogenesis in immature and mature L. emarginata provides an opportunity to examine the interdependence of central and peripheral neurogenesis in the olfactory pathway. This study demonstrates that the continuous addition of olfactory receptor neurons in L. emarginata ceases at the terminal moult but that proliferation and differentiation of olfactory interneurons in the brain continues in mature animals. Contrary to the general assumption, therefore, continuous neurogenesis in the central olfactory pathway of this species does not occur as part of a process involving the coregulation of central and peripheral neurogenesis. These findings suggest that peripheral neurogenesis is not a requirement for continuous neurogenesis in the central olfactory pathway. PMID:16307582

  2. Calcium permeable AMPA receptors and autoreceptors in external tufted cells of rat olfactory bulb

    PubMed Central

    Ma, Jie; Lowe, Graeme

    2007-01-01

    Glomeruli are functional units of the olfactory bulb responsible for early processing of odor information encoded by single olfactory receptor genes. Glomerular neural circuitry includes numerous external tufted (ET) cells whose rhythmic burst firing may mediate synchronization of bulbar activity with the inhalation cycle. Bursting is entrained by glutamatergic input from olfactory nerve terminals, so specific properties of ionotropic glutamate receptors on ET cells are likely to be important determinants of olfactory processing. Particularly intriguing is recent evidence that α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors of juxta-glomerular neurons may permeate calcium. This could provide a novel pathway for regulating ET cell signaling. We tested the hypothesis that ET cells express functional calcium-permeable AMPA receptors. In rat olfactory bulb slices, excitatory postsynaptic currents (EPSCs) in ET cells were evoked by olfactory nerve shock, and by uncaging glutamate. We found attenuation of AMPA/kainate EPSCs by 1-naphthyl acetyl-spermine (NAS), an open-channel blocker specific for calcium permeable AMPA receptors. Cyclothiazide strongly potentiated EPSCs, indicating a major contribution from AMPA receptors. The current-voltage (I-V) relation of uncaging EPSCs showed weak inward rectification which was lost after > ~ 10 min of whole-cell dialysis, and was absent in NAS. In kainate-stimulated slices, Co2+ ions permeated cells of the glomerular layer. Large AMPA EPSCs were accompanied by fluorescence signals in fluo-4 loaded cells, suggesting calcium permeation. Depolarizing pulses evoked slow tail currents with pharmacology consistent with involvement of calcium permeable AMPA autoreceptors. Tail currents were abolished by Cd2+ and NBQX, and were sensitive to NAS block. Glutamate autoreceptors were confirmed by uncaging intracellular calcium to evoke a large inward current. Our results provide evidence that calcium permeable AMPA

  3. Cloning and localization of two multigene receptor families in goldfish olfactory epithelium

    PubMed Central

    Cao, Yanxiang; Oh, Bryan C.; Stryer, Lubert

    1998-01-01

    Goldfish reproduction is coordinated by pheromones that are released by ovulating females and detected by males. Two highly potent pheromones, a dihydroxyprogesterone and a prostaglandin, previously have been identified, and their effects on goldfish behavior have been studied in depth. We have cloned goldfish olfactory epithelium cDNAs belonging to two multigene G-protein coupled receptor families as a step toward elucidating the molecular basis of pheromone recognition. One gene family (GFA) consists of homologs of putative odorant receptors (≈320 residues) found in the olfactory epithelium of other fish and mammals. The other family (GFB) consists of homologs of putative pheromone receptors found in the vomeronasal organ (VNO) of mammals and also in the nose of pufferfish. GFB receptors (≈840 residues) are akin to the V2R family of VNO receptors, which possess a large extracellular N-terminal domain and are homologs of calcium-sensing and metabotropic glutamate receptors. In situ hybridization showed that the two families of goldfish receptors are differentially expressed in the olfactory epithelium. GFB mRNA is abundant in rather compact cells whose nuclei are near the apical surface. In contrast, GFA mRNA is found in elongated cells whose nuclei are positioned deeper in the epithelium. Our findings support the hypothesis that the separate olfactory organ and VNO of terrestrial vertebrates arose in evolution by the segregation of distinct classes of neurons that were differentially positioned in the olfactory epithelium of a precursor aquatic vertebrate. PMID:9751777

  4. Characterization of the Olfactory Receptors Expressed in Human Spermatozoa

    PubMed Central

    Flegel, Caroline; Vogel, Felix; Hofreuter, Adrian; Schreiner, Benjamin S. P.; Osthold, Sandra; Veitinger, Sophie; Becker, Christian; Brockmeyer, Norbert H.; Muschol, Michael; Wennemuth, Gunther; Altmüller, Janine; Hatt, Hanns; Gisselmann, Günter

    2016-01-01

    The detection of external cues is fundamental for human spermatozoa to locate the oocyte in the female reproductive tract. This task requires a specific chemoreceptor repertoire that is expressed on the surface of human spermatozoa, which is not fully identified to date. Olfactory receptors (ORs) are candidate molecules and have been attributed to be involved in sperm chemotaxis and chemokinesis, indicating an important role in mammalian spermatozoa. An increasing importance has been suggested for spermatozoal RNA, which led us to investigate the expression of all 387 OR genes. This study provides the first comprehensive analysis of OR transcripts in human spermatozoa of several individuals by RNA-Seq. We detected 91 different transcripts in the spermatozoa samples that could be aligned to annotated OR genes. Using stranded mRNA-Seq, we detected a class of these putative OR transcripts in an antisense orientation, indicating a different function, rather than coding for a functional OR protein. Nevertheless, we were able to detect OR proteins in various compartments of human spermatozoa, indicating distinct functions in human sperm. A panel of various OR ligands induced Ca2+ signals in human spermatozoa, which could be inhibited by mibefradil. This study indicates that a variety of ORs are expressed at the mRNA and protein level in human spermatozoa. PMID:26779489

  5. Olfactory Processing and Behavior Downstream from Highly Selective Receptor Neurons

    PubMed Central

    Schlief, Michelle L.; Wilson, Rachel I.

    2010-01-01

    In either the vertebrate nose or the insect antenna, most olfactory receptor neurons (ORNs) respond to multiple odors. However, some ORNs respond to just a single odor, or at most to a few highly related odors. It has been hypothesized that narrowly-tuned ORNs project to narrowly-tuned neurons in the brain, and that these dedicated circuits mediate innate behavioral responses to a particular ligand. Here we have investigated neural activity and behavior downstream from two narrowly-tuned ORN types in Drosophila. We found that genetically ablating either of these ORN types impairs innate behavioral attraction to their cognate ligand. Neurons in the antennal lobe postsynaptic to one of these ORN types are, like their presynaptic ORNs, narrowly tuned to a pheromone. However, neurons postsynaptic to the second ORN type are broadly tuned. These results demonstrate that some narrowly-tuned ORNs project to dedicated central circuits, ensuring a tight connection between stimulus and behavior, whereas others project to central neurons which participate in the ensemble representations of many odors. PMID:17417635

  6. A Rapid Genotyping Assay for Segregating Human Olfactory Receptor Pseudogenes

    PubMed Central

    Hinkley, Craig S.; Ismaili, Lindita

    2012-01-01

    Variation in odor perception between individuals is initiated by binding of “odorant” molecules to olfactory receptors (ORs) located in the nasal cavity. To determine the mechanism for variation in odor perception, identification of specific ligands for a large number of ORs is required. However, it has been difficult to identify specific ligands, and ligands have been identified for only 2–3% of the hundreds of mammalian ORs. One way to increase the number of identified ligands is to take advantage of >60 human OR genes that are segregating as a result of a single nucleotide polymorphism, between a functional intact allele and a nonfunctional pseudogene allele. Potential ligands for these ORs can be identified by correlating odor perception of an individual with their genotype [intact/intact (I/I) vs. pseudogene/pseudogene (P/P)] for an OR gene. For this type of study, genotypes must be determined for a large number of individuals. We have developed a PCR-based assay to distinguish between the intact and pseudogene alleles of 49 segregating human OR genes and to determine an individual's genotype for these genes. To facilitate rapid determination of genotypes for a large number of individuals, the assay uses a small number of simple steps and equipment commonly found in most molecular biology and biochemistry laboratories. Although this assay was developed to distinguish between polymorphisms in OR genes, it can easily be adapted for use in distinguishing single nucleotide polymorphisms in any gene or chromosomal locus. PMID:23002384

  7. Detection of Volatile Indicators of Illicit Substances by the Olfactory Receptors of Drosophila melanogaster

    PubMed Central

    Marshall, Brenton; Warr, Coral G.

    2010-01-01

    Insects can detect a large range of odors with a numerically simple olfactory system that delivers high sensitivity and accurate discrimination. Therefore, insect olfactory receptors hold great promise as biosensors for detection of volatile organic chemicals in a range of applications. The array of olfactory receptor neurons of Drosophila melanogaster is rapidly becoming the best-characterized natural nose. We have investigated the suitability of Drosophila receptors as detectors for volatiles with applications in law enforcement, emergency response, and security. We first characterized responses of the majority of olfactory neuron types to a set of diagnostic odorants. Being thus able to correctly identify neurons, we then screened for responses from 38 different types of neurons to 35 agents. We identified 13 neuron types with responses to 13 agents. As individual Drosophila receptor genes have been mapped to neuron types, we can infer which genes confer responsiveness to the neurons. The responses were confirmed for one receptor by expressing it in a nonresponsive neuron. The fly olfactory system is mainly adapted to detect volatiles from fermenting fruits. However, our findings establish that volatiles associated with illicit substances, many of which are of nonnatural origin, are also detected by Drosophila receptors. PMID:20530374

  8. Efficient cell-free production of olfactory receptors: Detergent optimization, structure, and ligand binding analyses

    PubMed Central

    Kaiser, Liselotte; Graveland-Bikker, Johanna; Steuerwald, Dirk; Vanberghem, Mélanie; Herlihy, Kara; Zhang, Shuguang

    2008-01-01

    High-level production of membrane proteins, particularly of G protein-coupled receptors (GPCRs) in heterologous cell systems encounters a number of difficulties from their inherent hydrophobicity in their transmembrane domains, which frequently cause protein aggregation and cytotoxicity and thus reduce the protein yield. Recent advances in cell-free protein synthesis circumvent those problems to produce membrane proteins with a yield sometimes exceeding the cell-based approach. Here, we report cell-free production of a human olfactory receptor 17-4 (hOR17-4) using the wheat germ extract. Using the simple method, we also successful produced two additional olfactory receptors. To obtain soluble olfactory receptors and to increase yield, we directly added different detergents in varying concentrations to the cell-free reaction. To identify a purification buffer system that maintained the receptor in a nonaggregated form, we developed a method that uses small-volume size-exclusion column chromatography combined with rapid and sensitive dot-blot detection. Different buffer components including salt concentration, various detergents and detergent concentration, and reducing agent and its concentrations were evaluated for their ability to maintain the cell-free produced protein stable and nonaggregated. The purified olfactory receptor displays a typical a α-helical CD spectrum. Surface plasmon resonance measurements were used to show binding of a known ligand undecanal to hOR17-4. Our approach to produce a high yield of purified olfactory receptor is a milestone toward obtaining a large quantity of olfactory receptors for designing bionic sensors. Furthermore, this simple approach may be broadly useful not only for other classes of GPCRs but also for other membrane proteins. PMID:18840687

  9. Efficient cell-free production of olfactory receptors: detergent optimization, structure, and ligand binding analyses.

    PubMed

    Kaiser, Liselotte; Graveland-Bikker, Johanna; Steuerwald, Dirk; Vanberghem, Mélanie; Herlihy, Kara; Zhang, Shuguang

    2008-10-14

    High-level production of membrane proteins, particularly of G protein-coupled receptors (GPCRs) in heterologous cell systems encounters a number of difficulties from their inherent hydrophobicity in their transmembrane domains, which frequently cause protein aggregation and cytotoxicity and thus reduce the protein yield. Recent advances in cell-free protein synthesis circumvent those problems to produce membrane proteins with a yield sometimes exceeding the cell-based approach. Here, we report cell-free production of a human olfactory receptor 17-4 (hOR17-4) using the wheat germ extract. Using the simple method, we also successful produced two additional olfactory receptors. To obtain soluble olfactory receptors and to increase yield, we directly added different detergents in varying concentrations to the cell-free reaction. To identify a purification buffer system that maintained the receptor in a nonaggregated form, we developed a method that uses small-volume size-exclusion column chromatography combined with rapid and sensitive dot-blot detection. Different buffer components including salt concentration, various detergents and detergent concentration, and reducing agent and its concentrations were evaluated for their ability to maintain the cell-free produced protein stable and nonaggregated. The purified olfactory receptor displays a typical a alpha-helical CD spectrum. Surface plasmon resonance measurements were used to show binding of a known ligand undecanal to hOR17-4. Our approach to produce a high yield of purified olfactory receptor is a milestone toward obtaining a large quantity of olfactory receptors for designing bionic sensors. Furthermore, this simple approach may be broadly useful not only for other classes of GPCRs but also for other membrane proteins.

  10. High-affinity olfactory receptor for the death-associated odor cadaverine

    PubMed Central

    Hussain, Ashiq; Saraiva, Luis R.; Ferrero, David M.; Ahuja, Gaurav; Krishna, Venkatesh S.; Liberles, Stephen D.; Korsching, Sigrun I.

    2013-01-01

    Carrion smell is strongly repugnant to humans and triggers distinct innate behaviors in many other species. This smell is mainly carried by two small aliphatic diamines, putrescine and cadaverine, which are generated by bacterial decarboxylation of the basic amino acids ornithine and lysine. Depending on the species, these diamines may also serve as feeding attractants, oviposition attractants, or social cues. Behavioral responses to diamines have not been investigated in zebrafish, a powerful model system for studying vertebrate olfaction. Furthermore, olfactory receptors that detect cadaverine and putrescine have not been identified in any species so far. Here, we show robust olfactory-mediated avoidance behavior of zebrafish to cadaverine and related diamines, and concomitant activation of sparse olfactory sensory neurons by these diamines. The large majority of neurons activated by low concentrations of cadaverine expresses a particular olfactory receptor, trace amine-associated receptor 13c (TAAR13c). Structure-activity analysis indicates TAAR13c to be a general diamine sensor, with pronounced selectivity for odd chains of medium length. This receptor can also be activated by decaying fish extracts, a physiologically relevant source of diamines. The identification of a sensitive zebrafish olfactory receptor for these diamines provides a molecular basis for studying neural circuits connecting sensation, perception, and innate behavior. PMID:24218586

  11. Modulatory Effects of Sex Steroids Progesterone and Estradiol on Odorant Evoked Responses in Olfactory Receptor Neurons

    PubMed Central

    Scholz, Paul; Mohrhardt, Julia; Gisselmann, Günter; Hatt, Hanns

    2016-01-01

    The influence of the sex steroid hormones progesterone and estradiol on physiology and behavior during menstrual cycles and pregnancy is well known. Several studies indicate that olfactory performance changes with cyclically fluctuating steroid hormone levels in females. Knowledge of the exact mechanisms behind how female sex steroids modulate olfactory signaling is limited. A number of different known genomic and non-genomic actions that are mediated by progesterone and estradiol via interactions with different receptors may be responsible for this modulation. Next generation sequencing-based RNA-Seq transcriptome data from the murine olfactory epithelium (OE) and olfactory receptor neurons (ORNs) revealed the expression of several membrane progestin receptors and the estradiol receptor Gpr30. These receptors are known to mediate rapid non-genomic effects through interactions with G proteins. RT-PCR and immunohistochemical staining results provide evidence for progestin and estradiol receptors in the ORNs. These data support the hypothesis that steroid hormones are capable of modulating the odorant-evoked activity of ORNs. Here, we validated this hypothesis through the investigation of steroid hormone effects by submerged electro-olfactogram and whole cell patch-clamp recordings of ORNs. For the first time, we demonstrate that the sex steroid hormones progesterone and estradiol decrease odorant-evoked signals in the OE and ORNs of mice at low nanomolar concentrations. Thus, both of these sex steroids can rapidly modulate the odor responsiveness of ORNs through membrane progestin receptors and the estradiol receptor Gpr30. PMID:27494699

  12. The β2-adrenergic receptor as a surrogate odorant receptor in mouse olfactory sensory neurons

    PubMed Central

    Omura, Masayo; Grosmaitre, Xavier; Ma, Minghong; Mombaerts, Peter

    2015-01-01

    In the mouse, mature olfactory sensory neurons (OSNs) express one allele of one of the ~1200 odorant receptor (OR) genes, which encode G-protein coupled receptors (GPCRs). Axons of OSNs that express the same OR coalesce into homogeneous glomeruli at conserved positions in the olfactory bulb. ORs are involved in OR gene choice and OSN axonal wiring, but the mechanisms remain poorly understood. One approach is to substitute an OR genetically with another GPCR, and to determine in which aspects this GPCR can serve as a surrogate OR under experimental conditions. Here, we characterize a novel gene-targeted mouse strain in which the mouse β2-adrenergic receptor (β2AR) is coexpressed with tauGFP in OSNs that choose the OR locus M71 for expression (β2AR→M71-GFP). By crossing these mice with β2AR→M71-lacZ gene-targeted mice, we find that differentially tagged β2AR→M71 alleles are expressed monoallelically. The OR coding sequence is thus not required for monoallelic expression — the expression of one of the two alleles of a given OR gene in an OSN. We detect strong β2AR immunoreactivity in dendritic cilia of β2AR→M71-GFP OSNs. These OSNs respond to the β2AR agonist isoproterenol in a dose-dependent manner. Axons of β2AR→M71-GFP OSNs coalesce into homogeneous glomeruli, and β2AR immunoreactivity is detectable within these glomeruli. We do not find evidence for expression of endogenous β2AR in OSNs of wild-type mice, also not in M71-expressing OSNs, and we do not observe overt differences in the olfactory system of β2AR and β1AR knockout mice. Our findings corroborate the experimental value of the β2AR as a surrogate OR, including for the study of the mechanisms of monoallelic expression. PMID:24211702

  13. Drosophila olfactory receptors as classifiers for volatiles from disparate real world applications.

    PubMed

    Nowotny, Thomas; de Bruyne, Marien; Berna, Amalia Z; Warr, Coral G; Trowell, Stephen C

    2014-01-01

    Olfactory receptors evolved to provide animals with ecologically and behaviourally relevant information. The resulting extreme sensitivity and discrimination has proven useful to humans, who have therefore co-opted some animals' sense of smell. One aim of machine olfaction research is to replace the use of animal noses and one avenue of such research aims to incorporate olfactory receptors into artificial noses. Here, we investigate how well the olfactory receptors of the fruit fly, Drosophila melanogaster, perform in classifying volatile odourants that they would not normally encounter. We collected a large number of in vivo recordings from individual Drosophila olfactory receptor neurons in response to an ecologically relevant set of 36 chemicals related to wine ('wine set') and an ecologically irrelevant set of 35 chemicals related to chemical hazards ('industrial set'), each chemical at a single concentration. Resampled response sets were used to classify the chemicals against all others within each set, using a standard linear support vector machine classifier and a wrapper approach. Drosophila receptors appear highly capable of distinguishing chemicals that they have not evolved to process. In contrast to previous work with metal oxide sensors, Drosophila receptors achieved the best recognition accuracy if the outputs of all 20 receptor types were used. PMID:25313522

  14. Olfactory receptor cells respond to odors in a tissue and semiconductor hybrid neuron chip.

    PubMed

    Liu, Qingjun; Ye, Weiwei; Hu, Ning; Cai, Hua; Yu, Hui; Wang, Ping

    2010-12-15

    Olfactory systems of human beings and animals have the abilities to sense and distinguish varieties of odors. In this study, a bioelectronic nose was constructed by fixing biological tissues onto the surface of light-addressable potentiometric sensor (LAPS) to mimic human olfaction and realize odor differentiation. The odorant induced potentials on tissue-semiconductor interface was analyzed by sensory transduction theory and sheet conductor model. The extracellular potentials of the receptor cells in the olfactory epithelium were detected by LAPS. Being stimulated by different odorants, such as acetic acid and butanedione, olfactory epithelium activities were analyzed on basis of local field potentials and presented different firing modes. The signals fired in different odorants could be distinguished into different clusters by principal component analysis (PCA). Therefore, with cellular populations well preserved, the epithelium tissue and LAPS hybrid system will be a promising neuron chip of olfactory biosensors for odor detecting.

  15. Induction of an Olfactory Memory by the Activation of a Metabotropic Glutamate Receptor

    NASA Astrophysics Data System (ADS)

    Kaba, Hideto; Hayashi, Yasunori; Higuchi, Takashi; Nakanishi, Shigetada

    1994-07-01

    Female mice form an olfactory memory of male pheromones at mating; exposure to the pheromones of a strange male after that mating will block pregnancy. The formation of this memory is mediated by the accessory olfactory system, in which an increase in norepinephrine after mating reduces inhibitory transmission of γ-aminobutyric acid from the granule cells to the mitral cells. This study shows that the activation of mGluR2, a metabotropic glutamate receptor that suppresses the γ-aminobutyric acid inhibition of the mitral cells, permits the formation of a specific olfactory memory without the occurrence of mating by infusion of mGluR2 agonists into the female's accessory olfactory bulb. This memory faithfully reflects the memory formed at mating.

  16. Positive Darwinian selection and the birth of an olfactory receptor clade in teleosts

    PubMed Central

    Hussain, Ashiq; Saraiva, Luis R.; Korsching, Sigrun I.

    2009-01-01

    Trace amine-associated receptors (TAARs) in mammals recently have been shown to function as olfactory receptors. We have delineated the taar gene family in jawless, cartilaginous, and bony fish (zero, 2, and >100 genes, respectively). We conclude that taar genes are evolutionary much younger than the related OR and ORA/V1R olfactory receptor families, which are present already in lamprey, a jawless vertebrate. The 2 cartilaginous fish genes appear to be ancestral for 2 taar classes, each with mammalian and bony fish (teleost) representatives. Unexpectedly, a whole new clade, class III, of taar genes originated even later, within the teleost lineage. Taar genes from all 3 classes are expressed in subsets of zebrafish olfactory receptor neurons, supporting their function as olfactory receptors. The highly conserved TAAR1 (shark, mammalian, and teleost orthologs) is not expressed in the olfactory epithelium and may constitute the sole remnant of a primordial, nonolfactory function of this family. Class III comprises three-fourths of all teleost taar genes and is characterized by the complete loss of the aminergic ligand-binding motif, stringently conserved in the other 2 classes. Two independent intron gains in class III taar genes represent extraordinary evolutionary dynamics, considering the virtual absence of intron gains during vertebrate evolution. The dN/dS analysis suggests both minimal global negative selection and an unparalleled degree of local positive selection as another hallmark of class III genes. The accelerated evolution of class III teleost taar genes conceivably might mark the birth of another olfactory receptor gene family. PMID:19237578

  17. Epigenetic regulation of olfactory receptor gene expression by the Myb-MuvB/dREAM complex.

    PubMed

    Sim, Choon Kiat; Perry, Sarah; Tharadra, Sana Khalid; Lipsick, Joseph S; Ray, Anandasankar

    2012-11-15

    In both mammals and insects, an olfactory neuron will usually select a single olfactory receptor and repress remaining members of large receptor families. Here we show that a conserved multiprotein complex, Myb-MuvB (MMB)/dREAM, plays an important role in mediating neuron-specific expression of the carbon dioxide (CO(2)) receptor genes (Gr63a/Gr21a) in Drosophila. Activity of Myb in the complex is required for expression of Gr63a/Gr21a and acts in opposition to the histone methyltransferase Su(var)3-9. Consistent with this, we observed repressive dimethylated H3K9 modifications at the receptor gene loci, suggesting a mechanism for silencing receptor gene expression. Conversely, other complex members, Mip120 (Myb-interacting protein 120) and E2F2, are required for repression of Gr63a in inappropriate neurons. Misexpression in mutants is accompanied by an increase in the H3K4me3 mark of active chromatin at the receptor gene locus. Nuclei of CO(2) receptor-expressing neurons contain reduced levels of the repressive subunit Mip120 compared with surrounding neurons and increased levels of Myb, suggesting that activity of the complex can be regulated in a cell-specific manner. Our evidence suggests a model in which olfactory receptors are regulated epigenetically and the MMB/dREAM complex plays a critical role in specifying, maintaining, and modulating the receptor-to-neuron map.

  18. Awaken olfactory receptors of humans and experimental animals by coffee odourants to induce appetite.

    PubMed

    Dorri, Yaser; Sabeghi, Maryam; Kurien, Biji T

    2007-01-01

    Smell and its mechanism has been of interest to scientists for many years. Smell, not only provides a sensual pleasure of food and perfumes for humans but also reminds us of past memories, thoughts, locations and finally warns of dangers such as fire. One of the uses of coffee beans is on perfume counters, enabling people to distinguish between perfume fragrances. We hypothesize that coffee can be also used to refresh olfactory receptors after cooking, since people usually experience loss of appetite after cooking. We have experienced an increase in appetite, after cooking, by smelling coffee beans. This is probably due to the detachment of food odourants from olfactory receptors by the coffee odourant molecules. We also think that coffee smell could be used in animal research studies, to keep animals healthy by stimulating their appetite. In a recent study, 28 different odourants have been identified from coffee. One or more of these odourants may have strong binding affinity to olfactory receptors which results in detachment of other odourants from the receptors. The high vibration intensity from coffee odourant molecules may cause the detachment of food odourant from olfactory receptors. Another hypothesis might be the unique structure of these coffee odourants. Studies need to be done to investigate the effect of coffee smell on salivary flow and appetite in animals and humans.

  19. Distinct Roles of Bulbar Muscarinic and Nicotinic Receptors in Olfactory Discrimination Learning

    PubMed Central

    Devore, Sasha; de Almeida, Licurgo

    2014-01-01

    The olfactory bulb (OB) and piriform cortex receive dense cholinergic projections from the basal forebrain. Cholinergic modulation within the piriform cortex has long been proposed to serve important functions in olfactory learning and memory. We here investigate how olfactory discrimination learning is regulated by cholinergic modulation of the OB inputs to the piriform cortex. We examined rats' performance on a two-alternative choice odor discrimination task following local, bilateral blockade of cholinergic nicotinic and/or muscarinic receptors in the OB. Results demonstrate that acquisition, but not recall, of novel discrimination problems is impaired following blockade of OB cholinergic receptors, although the relative contribution of muscarinic and nicotinic receptors depends on task difficulty. Blocking muscarinic receptors impairs learning for nearly all odor sets, whereas blocking nicotinic receptors only affects performance for perceptually similar odors. This pattern of behavioral effects is consistent with predictions from a model of cholinergic modulation in the OB and piriform cortex (de Almeida et al., 2013). Model simulations suggest that muscarinic and nicotinic receptors may serve complementary roles in regulating coherence and sparseness of the OB network output, which in turn differentially regulate the strength and overlap in cortical odor representations. Overall, our results suggest that muscarinic receptor blockade results in a bona fide learning impairment that may arise because cortical neurons are activated less often. Behavioral impairment following nicotinic receptor blockade may not be due to the inability of the cortex to learn, but rather arises because the cortex is unable to resolve highly overlapping input patterns. PMID:25143606

  20. Transduction proteins of olfactory receptor cells: identification of guanine nucleotide binding proteins and protein kinase C

    SciTech Connect

    Anholt, R.R.H.; Mumby, S.M.; Stoffers, D.A.; Girard, P.R.; Kuo, J.F.; Snyder, S.H.

    1987-02-10

    The authors have analyzed guanine nucleotide binding proteins (G-proteins) in the olfactory epithelium of Rana catesbeiana using subunit-specific antisera. The olfactory epithelium contained the ..cap alpha.. subunits of three G-proteins, migrating on polyacrylamide gels in SDS with apparent molecular weights of 45,000, 42,000, and 40,000, corresponding to G/sub s/, G/sub i/, and G/sub o/, respectively. A single ..beta.. subunit with an apparent molecular weight of 36,000 was detected. An antiserum against the ..cap alpha.. subunit of retinal transducin failed to detect immunoreactive proteins in olfactory cilia detached from the epithelium. The olfactory cilia appeared to be enriched in immunoreactive G/sub s..cap alpha../ relative to G/sub ichemically bond/ and G/sub ochemically bond/ when compared to membranes prepared from the olfactory epithelium after detachment of the cilia. Bound antibody was detected by autoradiography after incubation with (/sup 125/I)protein. Immunohistochemical studies using an antiserum against the ..beta.. subunit of G-proteins revealed intense staining of the ciliary surface of the olfactory epithelium and of the axon bundles in the lamina propria. In contrast, an antiserum against a common sequence of the ..cap alpha.. subunits preferentially stained the cell membranes of the olfactory receptor cells and the acinar cells of Bowman's glands and the deep submucosal glands. In addition to G-proteins, they have identified protein kinase C in olfactory cilia via a protein kinase C specific antiserum and via phorbol ester binding. However, in contrast to the G-proteins, protein kinase C occurred also in cilia isolated from respiratory epithelium.

  1. Dialing Up an Embryo: Are Olfactory Receptors Digits in a Developmental Code?

    ERIC Educational Resources Information Center

    Travis, John

    1998-01-01

    Scientist William J. Dreyer has hypothesized that the cell surface proteins in the nose that detect odors also help assemble embryos. These olfactory receptors and related proteins act as identifiers, much like the last few digits of a telephone number, that help cells to find their intended neighbors in a developing embryo. Discusses the research…

  2. Positive selection moments identify potential functional residues in human olfactory receptors

    NASA Technical Reports Server (NTRS)

    Singer, M. S.; Weisinger-Lewin, Y.; Lancet, D.; Shepherd, G. M.

    1996-01-01

    Correlated mutation analysis and molecular models of olfactory receptors have provided evidence that residues in the transmembrane domains form a binding pocket for odor ligands. As an independent test of these results, we have calculated positive selection moments for the alpha-helical sixth transmembrane domain (TM6) of human olfactory receptors. The moments can be used to identify residues that have been preferentially affected by positive selection and are thus likely to interact with odor ligands. The results suggest that residue 622, which is commonly a serine or threonine, could form critical H-bonds. In some receptors a dual-serine subsite, formed by residues 622 and 625, could bind hydroxyl determinants on odor ligands. The potential importance of these residues is further supported by site-directed mutagenesis in the beta-adrenergic receptor. The findings should be of practical value for future physiological studies, binding assays, and site-directed mutagenesis.

  3. X-ray fluorescence microscopy of olfactory receptor neurons

    NASA Astrophysics Data System (ADS)

    Dučić, T.; Breunig, E.; Schild, D.; Herbst, J.; Nováková, E.; Susini, J.; Tucoulu, R.; Salditt, T.

    2009-09-01

    We report a x-ray fluorescence microscopy study of cells and tissues from the olfactory system of Xenopus laevis. In this experiment we focus on sample preparation and experimental issues, and present first results of fluorescence maps of the elemental distribution of Cl, K, Ca, P, S and Na both in individual isolated neural cells and in cross-sections of the same tissue.

  4. Primary culture of embryonic rat olfactory receptor neurons.

    PubMed

    Micholt, Evelien; Jans, Danny; Callewaert, Geert; Bartic, Carmen; Lammertyn, Jeroen; Nicolai, Bart

    2012-12-01

    Embryonic cells are very robust in surviving dissection and culturing protocols and easily adapt to their in vitro environment. Despite these advantages, research in the olfactory field on cultured embryonic olfactory neurons is sparse. In this study, two primary rat olfactory explant cultures of different embryonic d (E17 and E20) were established, comprising epithelium and bulb. The functionality of these neurons was tested by measuring intracellular calcium responses to cAMP-inducing agents forskolin (FSK) and 3-isobutyl-1-methylxanthine (IBMX) with fluorescence microscopy. For E17, the responsive cell fraction increased over time, from an initial 3% at the 1 d in vitro (DIV) to a maximum of 19% at 11 DIV. The response of E20 neurons fluctuated over time around a more or less stable 13%. A logistic regression analysis indicated a significant difference between both embryonic d in the response to FSK + IBMX. In addition, of these functional neurons, 23.3% of E17 and 54.3% of E20 cultures were responsive to the odorant isoamyl acetate. PMID:23150136

  5. Southern pine beetle: Olfactory receptor and behavior discrimination of enantiomers of the attractant pheromone frontalin

    SciTech Connect

    Payne, T.L.; Berisford, C.W.; Blum, M.S.; Dickens, J.C.; Hedden, R.L.; Mori, K.; Richerson, J.V.; Vite, J.P.; West, J.R.

    1982-05-01

    In a laboratory and field bioassays, the response of Dendroctonus frontalis was significantly greater to the mixture of (1S,55R)-(-)-frontalin and alpha-pinene than to (1R,5S)-(+)-frontalin and alpha-pinene. Electrophysiologrical studies revealed that antennal olfactory receptor cells were significantly more responsive to (1S,5R)-(-)-frontalin than to 1R,5S)-(+) -frontalin. Both enanitiomers stimulated the same olfactory cells which suggests that each cell possesses at least two types of enanitomer-specific acceptors.

  6. High-speed odor transduction and pulse tracking by insect olfactory receptor neurons

    PubMed Central

    Szyszka, Paul; Gerkin, Richard C.; Galizia, C. Giovanni; Smith, Brian H.

    2014-01-01

    Sensory systems encode both the static quality of a stimulus (e.g., color or shape) and its kinetics (e.g., speed and direction). The limits with which stimulus kinetics can be resolved are well understood in vision, audition, and somatosensation. However, the maximum temporal resolution of olfactory systems has not been accurately determined. Here, we probe the limits of temporal resolution in insect olfaction by delivering high frequency odor pulses and measuring sensory responses in the antennae. We show that transduction times and pulse tracking capabilities of olfactory receptor neurons are faster than previously reported. Once an odorant arrives at the boundary layer of the antenna, odor transduction can occur within less than 2 ms and fluctuating odor stimuli can be resolved at frequencies more than 100 Hz. Thus, insect olfactory receptor neurons can track stimuli of very short duration, as occur when their antennae encounter narrow filaments in an odor plume. These results provide a new upper bound to the kinetics of odor tracking in insect olfactory receptor neurons and to the latency of initial transduction events in olfaction. PMID:25385618

  7. The Membrane Proteome of Sensory Cilia to the Depth of Olfactory Receptors*

    PubMed Central

    Kuhlmann, Katja; Tschapek, Astrid; Wiese, Heike; Eisenacher, Martin; Meyer, Helmut E.; Hatt, Hanns H.; Oeljeklaus, Silke; Warscheid, Bettina

    2014-01-01

    In the nasal cavity, the nonmotile cilium of olfactory sensory neurons (OSNs) constitutes the chemosensory interface between the ambient environment and the brain. The unique sensory organelle facilitates odor detection for which it includes all necessary components of initial and downstream olfactory signal transduction. In addition to its function in olfaction, a more universal role in modulating different signaling pathways is implicated, for example, in neurogenesis, apoptosis, and neural regeneration. To further extend our knowledge about this multifunctional signaling organelle, it is of high importance to establish a most detailed proteome map of the ciliary membrane compartment down to the level of transmembrane receptors. We detached cilia from mouse olfactory epithelia via Ca2+/K+ shock followed by the enrichment of ciliary membrane proteins at alkaline pH, and we identified a total of 4,403 proteins by gel-based and gel-free methods in conjunction with high resolution LC/MS. This study is the first to report the detection of 62 native olfactory receptor proteins and to provide evidence for their heterogeneous expression at the protein level. Quantitative data evaluation revealed four ciliary membrane-associated candidate proteins (the annexins ANXA1, ANXA2, ANXA5, and S100A5) with a suggested function in the regulation of olfactory signal transduction, and their presence in ciliary structures was confirmed by immunohistochemistry. Moreover, we corroborated the ciliary localization of the potassium-dependent Na+/Ca2+ exchanger (NCKX) 4 and the plasma membrane Ca2+-ATPase 1 (PMCA1) involved in olfactory signal termination, and we detected for the first time NCKX2 in olfactory cilia. Through comparison with transcriptome data specific for mature, ciliated OSNs, we finally delineated the membrane ciliome of OSNs. The membrane proteome of olfactory cilia established here is the most complete today, thus allowing us to pave new avenues for the study of diverse

  8. DOR – a Database of Olfactory Receptors – Integrated Repository for Sequence and Secondary Structural Information of Olfactory Receptors in Selected Eukaryotic Genomes

    PubMed Central

    Nagarathnam, Balasubramanian; Karpe, Snehal D; Harini, Krishnan; Sankar, Kannan; Iftekhar, Mohammed; Rajesh, Durairaj; Giji, Sadasivam; Archunan, Govidaraju; Balakrishnan, Veluchamy; Gromiha, M Michael; Nemoto, Wataru; Fukui, Kazhuhiko; Sowdhamini, Ramanathan

    2014-01-01

    Olfaction is the response to odors and is mediated by a class of membrane-bound proteins called olfactory receptors (ORs). An understanding of these receptors serves as a good model for basic signal transduction mechanisms and also provides important clues for the strategies adopted by organisms for their ultimate survival using chemosensory perception in search of food or defense against predators. Prior research on cross-genome phylogenetic analyses from our group motivated the addressal of conserved evolutionary trends, clustering, and ortholog prediction of ORs. The database of olfactory receptors (DOR) is a repository that provides sequence and structural information on ORs of selected organisms (such as Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans, Mus musculus, and Homo sapiens). Users can download OR sequences, study predicted membrane topology, and obtain cross-genome sequence alignments and phylogeny, including three-dimensional (3D) structural models of 100 selected ORs and their predicted dimer interfaces. The database can be accessed from http://caps.ncbs.res.in/DOR. Such a database should be helpful in designing experiments on point mutations to probe into the possible dimerization modes of ORs and to even understand the evolutionary changes between different receptors. PMID:25002814

  9. Avian olfactory receptor gene repertoires: evidence for a well-developed sense of smell in birds?

    PubMed

    Steiger, Silke S; Fidler, Andrew E; Valcu, Mihai; Kempenaers, Bart

    2008-10-22

    Among vertebrates, the sense of smell is mediated by olfactory receptors (ORs) expressed in sensory neurons within the olfactory epithelium. Comparative genomic studies suggest that the olfactory acuity of mammalian species correlates positively with both the total number and the proportion of functional OR genes encoded in their genomes. In contrast to mammals, avian olfaction is poorly understood, with birds widely regarded as relying primarily on visual and auditory inputs. Here, we show that in nine bird species from seven orders (blue tit, Cyanistes caeruleus; black coucal, Centropus grillii; brown kiwi, Apteryx australis; canary, Serinus canaria; galah, Eolophus roseicapillus; red jungle fowl, Gallus gallus; kakapo, Strigops habroptilus; mallard, Anas platyrhynchos; snow petrel, Pagodroma nivea), the majority of amplified OR sequences are predicted to be from potentially functional genes. This finding is somewhat surprising as one previous report suggested that the majority of OR genes in an avian (red jungle fowl) genomic sequence are non-functional pseudogenes. We also show that it is not the estimated proportion of potentially functional OR genes, but rather the estimated total number of OR genes that correlates positively with relative olfactory bulb size, an anatomical correlate of olfactory capability. We further demonstrate that all the nine bird genomes examined encode OR genes belonging to a large gene clade, termed gamma-c, the expansion of which appears to be a shared characteristic of class Aves. In summary, our findings suggest that olfaction in birds may be a more important sense than generally believed. PMID:18628122

  10. Non-classical amine recognition evolved in a large clade of olfactory receptors

    PubMed Central

    Li, Qian; Tachie-Baffour, Yaw; Liu, Zhikai; Baldwin, Maude W; Kruse, Andrew C; Liberles, Stephen D

    2015-01-01

    Biogenic amines are important signaling molecules, and the structural basis for their recognition by G Protein-Coupled Receptors (GPCRs) is well understood. Amines are also potent odors, with some activating olfactory trace amine-associated receptors (TAARs). Here, we report that teleost TAARs evolved a new way to recognize amines in a non-classical orientation. Chemical screens de-orphaned eleven zebrafish TAARs, with agonists including serotonin, histamine, tryptamine, 2-phenylethylamine, putrescine, and agmatine. Receptors from different clades contact ligands through aspartates on transmembrane α-helices III (canonical Asp3.32) or V (non-canonical Asp5.42), and diamine receptors contain both aspartates. Non-classical monoamine recognition evolved in two steps: an ancestral TAAR acquired Asp5.42, gaining diamine sensitivity, and subsequently lost Asp3.32. Through this transformation, the fish olfactory system dramatically expanded its capacity to detect amines, ecologically significant aquatic odors. The evolution of a second, alternative solution for amine detection by olfactory receptors highlights the tremendous structural versatility intrinsic to GPCRs. DOI: http://dx.doi.org/10.7554/eLife.10441.001 PMID:26519734

  11. Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease.

    PubMed

    Ferrer, Isidro; Garcia-Esparcia, Paula; Carmona, Margarita; Carro, Eva; Aronica, Eleonora; Kovacs, Gabor G; Grison, Alice; Gustincich, Stefano

    2016-01-01

    Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein α subunit (Gαolf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs) are expressed in neurons of the human and murine central nervous system (CNS). In vitro studies have shown that these receptors react to external stimuli and therefore are equipped to be functional. However, ORs are not directly related to the detection of odors. Several molecules delivered from the blood, cerebrospinal fluid, neighboring local neurons and glial cells, distant cells through the extracellular space, and the cells' own self-regulating internal homeostasis can be postulated as possible ligands. Moreover, a single neuron outside the olfactory epithelium expresses more than one receptor, and the mechanism of transcriptional regulation may be different in olfactory epithelia and brain neurons. OR gene expression is altered in several neurodegenerative diseases including Parkinson's disease (PD), Alzheimer's disease (AD), progressive supranuclear palsy (PSP) and sporadic Creutzfeldt-Jakob disease (sCJD) subtypes MM1 and VV2 with disease-, region- and subtype-specific patterns. Altered gene expression is also observed in the prefrontal cortex in schizophrenia with a major but not total influence of chlorpromazine treatment. Preliminary parallel observations have also shown the presence of taste receptors (TASRs), mainly of the bitter taste family, in the mammalian brain, whose function is not related to taste. TASRs in brain are also abnormally regulated in neurodegenerative diseases. These seminal observations point to the need for further studies on ORs and TASRs chemoreceptors in the mammalian brain. PMID:27458372

  12. Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease

    PubMed Central

    Ferrer, Isidro; Garcia-Esparcia, Paula; Carmona, Margarita; Carro, Eva; Aronica, Eleonora; Kovacs, Gabor G.; Grison, Alice; Gustincich, Stefano

    2016-01-01

    Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein α subunit (Gαolf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs) are expressed in neurons of the human and murine central nervous system (CNS). In vitro studies have shown that these receptors react to external stimuli and therefore are equipped to be functional. However, ORs are not directly related to the detection of odors. Several molecules delivered from the blood, cerebrospinal fluid, neighboring local neurons and glial cells, distant cells through the extracellular space, and the cells’ own self-regulating internal homeostasis can be postulated as possible ligands. Moreover, a single neuron outside the olfactory epithelium expresses more than one receptor, and the mechanism of transcriptional regulation may be different in olfactory epithelia and brain neurons. OR gene expression is altered in several neurodegenerative diseases including Parkinson’s disease (PD), Alzheimer’s disease (AD), progressive supranuclear palsy (PSP) and sporadic Creutzfeldt-Jakob disease (sCJD) subtypes MM1 and VV2 with disease-, region- and subtype-specific patterns. Altered gene expression is also observed in the prefrontal cortex in schizophrenia with a major but not total influence of chlorpromazine treatment. Preliminary parallel observations have also shown the presence of taste receptors (TASRs), mainly of the bitter taste family, in the mammalian brain, whose function is not related to taste. TASRs in brain are also abnormally regulated in neurodegenerative diseases. These seminal observations point to the need for further studies on ORs and TASRs chemoreceptors in the mammalian brain. PMID:27458372

  13. High-throughput mapping of the promoters of the mouse olfactory receptor genes reveals a new type of mammalian promoter and provides insight into olfactory receptor gene regulation

    PubMed Central

    Clowney, E. Josephine; Magklara, Angeliki; Colquitt, Bradley M.; Pathak, Nidhi; Lane, Robert P.; Lomvardas, Stavros

    2011-01-01

    The olfactory receptor (OR) genes are the largest mammalian gene family and are expressed in a monogenic and monoallelic fashion in olfactory neurons. Using a high-throughput approach, we mapped the transcription start sites of 1085 of the 1400 murine OR genes and performed computational analysis that revealed potential transcription factor binding sites shared by the majority of these promoters. Our analysis produced a hierarchical model for OR promoter recognition in which unusually high AT content, a unique epigenetic signature, and a stereotypically positioned O/E site distinguish OR promoters from the rest of the murine promoters. Our computations revealed an intriguing correlation between promoter AT content and evolutionary plasticity, as the most AT-rich promoters regulate rapidly evolving gene families. Within the AT-rich promoter category the position of the TATA-box does not correlate with the transcription start site. Instead, a spike in GC composition might define the exact location of the TSS, introducing the concept of “genomic contrast” in transcriptional regulation. Finally, our experiments show that genomic neighborhood rather than promoter sequence correlates with the probability of different OR genes to be expressed in the same olfactory cell. PMID:21705439

  14. [The 2004 Nobel Prize for Physiology or Medicine for research into smell receptors and the organization of the olfactory system].

    PubMed

    Burbach, J P H

    2004-12-25

    The 2004 Nobel Prize for Physiology or Medicine has been awarded to Richard Axel and Linda B. Buck, for their discovery of smell receptors and the organisation of the olfactory system. Their original discovery concerned the identification of some 1000 genes that code for smell receptors in the olfactory epithelium of the rat. They also demonstrated that each receptor can only be activated by a limited number of odourants and that there is some overlap in specificity with other smell receptors. Odourants in inhaled air are specifically recognized and bound by the smell receptors on the olfactory neurones in the nasal epithelium. The activated neurones send an electrical signal to the mitral cells, the dendrites of which lie in the glomeruli of the olfactory bulb. In each olfactory neuron only one smell receptor gene is expressed. Neurones with the same type of receptor are spread throughout the epithelium but converge in the same glomerulus. An olfactory map is formed by means of mitral-cell projections which run to the cerebral cortex as well as to other parts of the brain. Possibly the information gained about odourants will be applied in the areas of physiology and pathophysiology; in the field of pharmacology for example where odourants may be used in the treatment of disorders of fertility, behaviour or mood.

  15. Achieving diverse and monoallelic olfactory receptor selection through dual-objective optimization design.

    PubMed

    Tian, Xiao-Jun; Zhang, Hang; Sannerud, Jens; Xing, Jianhua

    2016-05-24

    Multiple-objective optimization is common in biological systems. In the mammalian olfactory system, each sensory neuron stochastically expresses only one out of up to thousands of olfactory receptor (OR) gene alleles; at the organism level, the types of expressed ORs need to be maximized. Existing models focus only on monoallele activation, and cannot explain recent observations in mutants, especially the reduced global diversity of expressed ORs in G9a/GLP knockouts. In this work we integrated existing information on OR expression, and constructed a comprehensive model that has all its components based on physical interactions. Analyzing the model reveals an evolutionarily optimized three-layer regulation mechanism, which includes zonal segregation, epigenetic barrier crossing coupled to a negative feedback loop that mechanistically differs from previous theoretical proposals, and a previously unidentified enhancer competition step. This model not only recapitulates monoallelic OR expression, but also elucidates how the olfactory system maximizes and maintains the diversity of OR expression, and has multiple predictions validated by existing experimental results. Through making an analogy to a physical system with thermally activated barrier crossing and comparative reverse engineering analyses, the study reveals that the olfactory receptor selection system is optimally designed, and particularly underscores cooperativity and synergy as a general design principle for multiobjective optimization in biology.

  16. Endoplasmic reticulum degradation impedes olfactory G-protein coupled receptor functional expression

    PubMed Central

    Lu, Min; Staszewski, Lena; Echeverri, Fernando; Xu, Hong; Moyer, Bryan D

    2004-01-01

    Background Research on olfactory G-protein coupled receptors (GPCRs) has been severely impeded by poor functional expression in heterologous systems. Previously, we demonstrated that inefficient olfactory receptor (OR) expression at the plasma membrane is attributable, in part, to degradation of endoplasmic reticulum (ER)-retained ORs by the ubiquitin-proteasome system and sequestration of ORs in ER aggregates that are degraded by autophagy. Thus, experiments were performed to test the hypothesis that attenuation of ER degradation improves OR functional expression in heterologous cells. Results To develop means to increase the functional expression of ORs, we devised an approach to measure activation of the mOREG OR (Unigene # Mm.196680; Olfr73) through coupling to an olfactory cyclic nucleotide-gated cation channel (CNG). This system, which utilizes signal transduction machinery coupled to OR activation in native olfactory sensory neurons, was used to demonstrate that degradation, both by the ubiquitin-proteasome system and autophagy, limits mOREG functional expression. The stimulatory effects of proteasome and autophagy inhibitors on mOREG function required export from the ER and trafficking through the biosynthetic pathway. Conclusions These findings demonstrate that poor functional expression of mOREG in heterologous cells is improved by blocking proteolysis. Inhibition of ER degradation may improve the function of other ORs and assist future efforts to elucidate the molecular basis of odor discrimination. PMID:15369603

  17. Achieving diverse and monoallelic olfactory receptor selection through dual-objective optimization design.

    PubMed

    Tian, Xiao-Jun; Zhang, Hang; Sannerud, Jens; Xing, Jianhua

    2016-05-24

    Multiple-objective optimization is common in biological systems. In the mammalian olfactory system, each sensory neuron stochastically expresses only one out of up to thousands of olfactory receptor (OR) gene alleles; at the organism level, the types of expressed ORs need to be maximized. Existing models focus only on monoallele activation, and cannot explain recent observations in mutants, especially the reduced global diversity of expressed ORs in G9a/GLP knockouts. In this work we integrated existing information on OR expression, and constructed a comprehensive model that has all its components based on physical interactions. Analyzing the model reveals an evolutionarily optimized three-layer regulation mechanism, which includes zonal segregation, epigenetic barrier crossing coupled to a negative feedback loop that mechanistically differs from previous theoretical proposals, and a previously unidentified enhancer competition step. This model not only recapitulates monoallelic OR expression, but also elucidates how the olfactory system maximizes and maintains the diversity of OR expression, and has multiple predictions validated by existing experimental results. Through making an analogy to a physical system with thermally activated barrier crossing and comparative reverse engineering analyses, the study reveals that the olfactory receptor selection system is optimally designed, and particularly underscores cooperativity and synergy as a general design principle for multiobjective optimization in biology. PMID:27162367

  18. Elimination of a ligand gating site generates a supersensitive olfactory receptor

    PubMed Central

    Sharma, Kanika; Ahuja, Gaurav; Hussain, Ashiq; Balfanz, Sabine; Baumann, Arnd; Korsching, Sigrun I.

    2016-01-01

    Olfaction poses one of the most complex ligand-receptor matching problems in biology due to the unparalleled multitude of odor molecules facing a large number of cognate olfactory receptors. We have recently deorphanized an olfactory receptor, TAAR13c, as a specific receptor for the death-associated odor cadaverine. Here we have modeled the cadaverine/TAAR13c interaction, exchanged predicted binding residues by site-directed mutagenesis, and measured the activity of the mutant receptors. Unexpectedly we observed a binding site for cadaverine at the external surface of the receptor, in addition to an internal binding site, whose mutation resulted in complete loss of activity. In stark contrast, elimination of the external binding site generated supersensitive receptors. Modeling suggests this site to act as a gate, limiting access of the ligand to the internal binding site and thereby downregulating the affinity of the native receptor. This constitutes a novel mechanism to fine-tune physiological sensitivity to socially relevant odors. PMID:27323929

  19. Cannabinoid receptor signaling induces proliferation but not neurogenesis in the mouse olfactory epithelium.

    PubMed

    Hutch, Chelsea R; Hegg, Colleen C

    2016-01-01

    The olfactory epithelium actively generates neurons through adulthood, and this neurogenesis is tightly regulated by multiple factors that are not fully defined. Here, we examined the role of cannabinoids in the regulation of neurogenesis in the mouse olfactory epithelium. In vivo proliferation and cell lineage studies were performed in mice (C57BL/6 and cannabinoid type 1 and 2 receptor deficient strains) treated with cannabinoids directly (WIN 55,212-2 or 2-arachidonylglycerol ether) or indirectly via inhibition of cannabinoid hydrolytic enzymes. Cannabinoids increased proliferation in neonatal and adult mice, and had no effect on proliferation in cannabinoid type 1 and 2 receptor deficient adult mice. Pretreatment with the cannabinoid type1 receptor antagonist AM251 decreased cannabinoid-induced proliferation in adult mice. Despite a cannabinoid-induced increase in proliferation, there was no change in newly generated neurons or non-neuronal cells 16 d post-treatment. However, cannabinoid administration increased apoptotic cell death at 72 hours post-treatment and by 16 d the level of apoptosis dropped to control levels. Thus, cannabinoids induce proliferation, but do not induce neurogenesis nor non-neuronal cell generation. Cannabinoid receptor signaling may regulate the balance of progenitor cell survival and proliferation in adult mouse olfactory epithelium. PMID:27606334

  20. ORDB, HORDE, ODORactor and other on-line knowledge resources of olfactory receptor-odorant interactions

    PubMed Central

    Marenco, Luis; Wang, Rixin; McDougal, Robert; Olender, Tsviya; Twik, Michal; Bruford, Elspeth; Liu, Xinyi; Zhang, Jian; Lancet, Doron; Shepherd, Gordon; Crasto, Chiquito

    2016-01-01

    We present here an exploration of the evolution of three well-established, web-based resources dedicated to the dissemination of information related to olfactory receptors (ORs) and their functional ligands, odorants. These resources are: the Olfactory Receptor Database (ORDB), the Human Olfactory Data Explorer (HORDE) and ODORactor. ORDB is a repository of genomic and proteomic information related to ORs and other chemosensory receptors, such as taste and pheromone receptors. Three companion databases closely integrated with ORDB are OdorDB, ORModelDB and OdorMapDB; these resources are part of the SenseLab suite of databases (http://senselab.med.yale.edu). HORDE (http://genome.weizmann.ac.il/horde/) is a semi-automatically populated database of the OR repertoires of human and several mammals. ODORactor (http://mdl.shsmu.edu.cn/ODORactor/) provides information related to OR-odorant interactions from the perspective of the odorant. All three resources are connected to each other via web-links. Database URL: http://senselab.med.yale.edu; http://genome.weizmann.ac.il/horde/; http://mdl.shsmu.edu.cn/ODORactor/ PMID:27694208

  1. ORDB, HORDE, ODORactor and other on-line knowledge resources of olfactory receptor-odorant interactions

    PubMed Central

    Marenco, Luis; Wang, Rixin; McDougal, Robert; Olender, Tsviya; Twik, Michal; Bruford, Elspeth; Liu, Xinyi; Zhang, Jian; Lancet, Doron; Shepherd, Gordon; Crasto, Chiquito

    2016-01-01

    We present here an exploration of the evolution of three well-established, web-based resources dedicated to the dissemination of information related to olfactory receptors (ORs) and their functional ligands, odorants. These resources are: the Olfactory Receptor Database (ORDB), the Human Olfactory Data Explorer (HORDE) and ODORactor. ORDB is a repository of genomic and proteomic information related to ORs and other chemosensory receptors, such as taste and pheromone receptors. Three companion databases closely integrated with ORDB are OdorDB, ORModelDB and OdorMapDB; these resources are part of the SenseLab suite of databases (http://senselab.med.yale.edu). HORDE (http://genome.weizmann.ac.il/horde/) is a semi-automatically populated database of the OR repertoires of human and several mammals. ODORactor (http://mdl.shsmu.edu.cn/ODORactor/) provides information related to OR-odorant interactions from the perspective of the odorant. All three resources are connected to each other via web-links. Database URL: http://senselab.med.yale.edu; http://genome.weizmann.ac.il/horde/; http://mdl.shsmu.edu.cn/ODORactor/

  2. A inhibitor of Na+/Ca2+ exchange blocks activation of insect olfactory receptors

    PubMed Central

    Bobkov, Y; Corey, E; Ache, B

    2014-01-01

    Earlier we showed that the Na+/Ca2+ exchanger inhibitor, KB-R7943, potently blocks the odor-evoked activity of lobster olfactory receptor neurons. Here we extend that finding to recombinant mosquito olfactory receptors stably expressed in HEK cells. Using whole-cell and outside-out patch clamping and calcium imaging, we demonstrate that KB-R7943 blocks both the odorantgated current and the odorant-evoked calcium signal from two different OR complexes from the malaria vector mosquito, Anopheles gambiae, AgOr48 + AgOrco and AgOr65 + AgOrco. Both heteromeric and homomeric (Orco alone) OR complexes were susceptible to KB-R7943 blockade when activated by VUAA1, an agonist that targets the Orco channel subunit, suggesting the Orco subunit may be the target of the drug’s action. KB-R7943 represents a valuable tool to further investigate the functional properties of arthropod olfactory receptors and raises the interesting specter that activation of these ionotropic receptors is directly or indirectly linked to a Na+/Ca2+ exchanger, thereby providing a template for drug design potentially allowing improved control of insect pests and disease vectors. PMID:24996179

  3. An inhibitor of Na(+)/Ca(2+) exchange blocks activation of insect olfactory receptors.

    PubMed

    Bobkov, Y; Corey, E; Ache, B

    2014-07-25

    Earlier we showed that the Na(+)/Ca(2+) exchanger inhibitor, KB-R7943, potently blocks the odor-evoked activity of lobster olfactory receptor neurons. Here we extend that finding to recombinant mosquito olfactory receptors stably expressed in HEK cells. Using whole-cell and outside-out patch clamping and calcium imaging, we demonstrate that KB-R7943 blocks both the odorant-gated current and the odorant-evoked calcium signal from two different OR complexes from the malaria vector mosquito, Anopheles gambiae, AgOr48+AgOrco and AgOr65+AgOrco. Both heteromeric and homomeric (Orco alone) OR complexes were susceptible to KB-R7943 blockade when activated by VUAA1, an agonist that targets the Orco channel subunit, suggesting the Orco subunit may be the target of the drug's action. KB-R7943 represents a valuable tool to further investigate the functional properties of arthropod olfactory receptors and raises the interesting specter that activation of these ionotropic receptors is directly or indirectly linked to a Na(+)/Ca(2+) exchanger, thereby providing a template for drug design potentially allowing improved control of insect pests and disease vectors. PMID:24996179

  4. Temporal response dynamics of Drosophila olfactory sensory neurons depends on receptor type and response polarity

    PubMed Central

    Getahun, Merid N.; Wicher, Dieter; Hansson, Bill S.; Olsson, Shannon B.

    2012-01-01

    Insect olfactory sensory neurons (OSN) express a diverse array of receptors from different protein families, i.e. ionotropic receptors (IR), gustatory receptors (GR) and odorant receptors (OR). It is well known that insects are exposed to a plethora of odor molecules that vary widely in both space and time under turbulent natural conditions. In addition to divergent ligand specificities, these different receptors might also provide an increased range of temporal dynamics and sensitivities for the olfactory system. To test this, we challenged different Drosophila OSNs with both varying stimulus durations (10–2000 ms), and repeated stimulus pulses of key ligands at various frequencies (1–10 Hz). Our results show that OR-expressing OSNs responded faster and with higher sensitivity to short stimulations as compared to IR- and Gr21a-expressing OSNs. In addition, OR-expressing OSNs could respond to repeated stimulations of excitatory ligands up to 5 Hz, while IR-expressing OSNs required ~5x longer stimulations and/or higher concentrations to respond to similar stimulus durations and frequencies. Nevertheless, IR-expressing OSNs did not exhibit adaptation to longer stimulations, unlike OR- and Gr21a-OSNs. Both OR- and IR-expressing OSNs were also unable to resolve repeated pulses of inhibitory ligands as fast as excitatory ligands. These differences were independent of the peri-receptor environment in which the receptors were expressed and suggest that the receptor expressed by a given OSN affects both its sensitivity and its response to transient, intermittent chemical stimuli. OR-expressing OSNs are better at resolving low dose, intermittent stimuli, while IR-expressing OSNs respond more accurately to long-lasting odor pulses. This diversity increases the capacity of the insect olfactory system to respond to the diverse spatiotemporal signals in the natural environment. PMID:23162431

  5. Molecular profiling of activated olfactory neurons identifies odorant receptors for odors in vivo

    PubMed Central

    Jiang, Yue; Gong, Naihua Natalie; Hu, Xiaoyang Serene; Ni, Mengjue Jessica; Pasi, Radhika

    2015-01-01

    The mammalian olfactory system uses a large family of odorant receptors to detect and discriminate amongst a myriad of volatile odor molecules. Understanding odor coding requires comprehensive mapping between odorant receptors and corresponding odors. Here we present high–throughput in vivo identification of odorant receptor repertoires responding to odorants, using phosphorylated ribosome immunoprecipitation of mRNA from olfactory epithelium of odor–stimulated mice followed by RNA–Seq. This approach screens the endogenously expressed odorant receptors against an odor in one set of experiments, using awake and freely behaving mice. In combination with validations in a heterologous system, we identify sets of odorant receptors for two odorants, acetophenone and 2,5–dihydro–2,4,5–trimethylthiazoline (TMT), encompassing 69 odorant receptor–odorant pairs. We also identified shared amino acid residues specific to the acetophenone or TMT receptors, and developed models to predict receptor activation by acetophenone. This study provides a means to understand the combinatorial coding of odors in vivo. PMID:26322927

  6. Predictive Assessments of Non-conventional Pollutants

    EPA Science Inventory

    In some situations, ecoepidemiological methods are the reasonable choice for setting effect benchmarks (e.g., protective criteria), especially for non-conventional pollutants. Ecoepidemiological methods are becoming more common because of advances in computational power and data...

  7. Comparison of research methods for functional characterization of insect olfactory receptors

    PubMed Central

    Wang, Bing; Liu, Yang; He, Kang; Wang, Guirong

    2016-01-01

    Insect olfactory receptors (ORs) in the peripheral olfactory system play an important role detecting elements of information from the environment. At present, various approaches are used for deorphanizing of ORs in insect. In this study, we compared methods for functional analysis of ORs in vitro and in vivo taking the candidate pheromone receptor OR13 of Helicoverpa assulta (HassOR13) as the object of our experiments. We found that the natural system was more sensitive than those utilizing transgenic Drosophila. The two-electrode voltage-clamp recording is more suitable for functional screening of large numbers of ORs, while the in vivo transgenic Drosophila system could prove more accurate to further validate the function of a specific OR. We also found that, among the different solvents used to dissolve pheromones and odorants, hexane offered good reproducibility and high sensitivity. Finally, the function of ORs was indirectly confirmed in transgenic Drosophila, showing that odor-activation of ORs-expressing olfactory receptor neurons (ORNs) can mediate behavioral choices. In summary, our results compare advantages and drawbacks of different approaches, thus helping in the choice of the method most suitable, in each specific situation, for deorphanizing insect ORs. PMID:27633402

  8. Comparison of research methods for functional characterization of insect olfactory receptors.

    PubMed

    Wang, Bing; Liu, Yang; He, Kang; Wang, Guirong

    2016-01-01

    Insect olfactory receptors (ORs) in the peripheral olfactory system play an important role detecting elements of information from the environment. At present, various approaches are used for deorphanizing of ORs in insect. In this study, we compared methods for functional analysis of ORs in vitro and in vivo taking the candidate pheromone receptor OR13 of Helicoverpa assulta (HassOR13) as the object of our experiments. We found that the natural system was more sensitive than those utilizing transgenic Drosophila. The two-electrode voltage-clamp recording is more suitable for functional screening of large numbers of ORs, while the in vivo transgenic Drosophila system could prove more accurate to further validate the function of a specific OR. We also found that, among the different solvents used to dissolve pheromones and odorants, hexane offered good reproducibility and high sensitivity. Finally, the function of ORs was indirectly confirmed in transgenic Drosophila, showing that odor-activation of ORs-expressing olfactory receptor neurons (ORNs) can mediate behavioral choices. In summary, our results compare advantages and drawbacks of different approaches, thus helping in the choice of the method most suitable, in each specific situation, for deorphanizing insect ORs. PMID:27633402

  9. Y1 receptors are critical for the proliferation of adult mouse precursor cells in the olfactory neuroepithelium.

    PubMed

    Doyle, Kharen L; Karl, Tim; Hort, Yvonne; Duffy, Liesl; Shine, John; Herzog, Herbert

    2008-05-01

    While the regenerative capacity of the olfactory neuroepithelium has been well studied less is known about the molecular events controlling precursor cell activity. Neuropeptide Y (NPY) is expressed at high levels in the olfactory system, and NPY has been shown to play a role in neuroregeneration of the brain. In this study, we show that the numbers of olfactory neurospheres derived from NPY, NPY/peptide YY, and Y1 receptor knockout mice are decreased compared with wild type (WT) controls. Furthermore, flow cytometric analysis of isolated horizontal basal cells, globose basal cells, and glandular cells showed that only glandular cells derived from WT mice, but not from NPY and Y1 receptor knockout mice, formed secondary neurospheres suggesting a critical role for NPY signaling in this process. Interestingly, olfactory function tests revealed that olfaction in Y1 knockout mice is impaired compared with those of WT mice, probably because of the reduced number of olfactory neurons formed. Together these results indicate that NPY and the Y1 receptor are required for the normal proliferation of adult olfactory precursors and olfactory function.

  10. Expanding the olfactory code by in silico decoding of odor-receptor chemical space

    PubMed Central

    Boyle, Sean Michael; McInally, Shane; Ray, Anandasankar

    2013-01-01

    Coding of information in the peripheral olfactory system depends on two fundamental factors: interaction of individual odors with subsets of the odorant receptor repertoire and mode of signaling that an individual receptor-odor interaction elicits, activation or inhibition. We develop a cheminformatics pipeline that predicts receptor–odorant interactions from a large collection of chemical structures (>240,000) for receptors that have been tested to a smaller panel of odorants (∼100). Using a computational approach, we first identify shared structural features from known ligands of individual receptors. We then use these features to screen in silico new candidate ligands from >240,000 potential volatiles for several Odorant receptors (Ors) in the Drosophila antenna. Functional experiments from 9 Ors support a high success rate (∼71%) for the screen, resulting in identification of numerous new activators and inhibitors. Such computational prediction of receptor–odor interactions has the potential to enable systems level analysis of olfactory receptor repertoires in organisms. DOI: http://dx.doi.org/10.7554/eLife.01120.001 PMID:24137542

  11. Current relaxation of selection on the human genome: tolerance of deleterious mutations on olfactory receptors.

    PubMed

    Pierron, Denis; Cortés, Nicolás Gutiérrez; Letellier, Thierry; Grossman, Lawrence I

    2013-02-01

    Knowledge and understanding about the selective pressures that have shaped present human genetic diversity have dramatically increased in the last few years in parallel with the availability of large genomic datasets. The release of large datasets composed of millions of SNPs across hundreds of genomes by HAPMAP, the Human Genome Diversity Panel, and other projects has led to considerable effort to detect selection signals across the nuclear genome (Coop et al., 2009; Lopez Herraez et al., 2009; Sabeti et al., 2006, 2007; Voight et al., 2006). Most of the research has focused on positive selection forces although other selective forces, such as negative selection, may have played a substantive role on the shape of our genome. Here we studied the selective strengths acting presently on the genome by making computational predictions of the pathogenicity of nonsynonymous protein mutations and interpreting the distribution of scores in terms of selection. We could show that the genetic diversity for all the major pathways is still constrained by negative selection in all 11 human populations studied. In a single exception, we observed a relaxation of negative selection acting on olfactory receptors. Since a decreased number of functioning olfactory receptors in human compared with other primates had already been shown, this suggests that the role of olfactory receptors for survival and reproductive success has decreased during human evolution. By showing that negative selection is still relaxed, the present results imply that no plateau of minimal function has yet been reached in modern humans and therefore that olfactory capability might still be decreasing. This is a first clue to present human evolution. PMID:22906809

  12. Evolution of olfactory receptor in oriental fruit fly Dacus dorsalis

    PubMed Central

    Metcalf, Robert L.; Metcalf, Esther R.; Mitchell, W. C.; Lee, Lena W. Y.

    1979-01-01

    Male oriental fruit flies (Dacus dorsalis) from colonies in Taiwan and Hawaii were evaluated for limit of response to various analogues of methyl eugenol. The results are interpreted in terms of the geometry and allosteric requirements of the antennal receptor that triggers the characteristic methyl eugenol reflex. This receptor has evolved for complementarity to all portions of the methyl eugenol molecule and responds only to ortho-substituted benzenes with adjacent oxygen atoms or isoelectronic equivalents. Substantial differences in responses of Taiwan and Hawaiian D. dorsalis suggest that perceptible evolution of the receptor protein has occurred during the past 50 years. A plausible scheme for the coevolution of dacini flies with plants containing phenylpropionoid essential oils is outlined. Images PMID:16592640

  13. Interactions of odorants with olfactory receptors and other preprocessing mechanisms: how complex and difficult to predict?

    PubMed

    Rospars, Jean-Pierre

    2013-05-01

    In this issue of Chemical Senses, Münch et al. present a thorough analysis of how mixtures of odorants interact with olfactory receptors (ORs) borne by olfactory receptor neurons (ORNs). Using fruit fly ORNs expressing the receptor OR22a, they provide a clear example of mixture interaction and confirm that the response of an ORN to a binary mixture can be sometimes predicted quantitatively knowing the ORN responses to its components as shown previously in rat ORNs. The prediction is based on a nonlinear model that assumes a classical 2-step activation of the OR and competition of the 2 odorants in the mixture for the same binding site. Can this success be generalized to all odorant-receptor pairs? This would be an encouraging perspective, especially for the fragrance and flavor industries, as it would permit the prediction of all mixtures. To address this question, I outline its conceptual framework and discuss the variety of mixture interactions found so far. In accordance with the effects described in the study of other receptors, several kinds of mixture interactions have been found that are not easily predictable. The relative importance of the predictable and less predictable effects thus appears as a major issue for future developments.

  14. Short-term memory trace mediated by termination kinetics of olfactory receptor

    PubMed Central

    Boyle, Sean Michael; McInally, Shane; Tharadra, Sana; Ray, Anandasankar

    2016-01-01

    Odorants activate receptors in the peripheral olfactory neurons, which sends information to higher brain centers where behavioral valence is determined. Movement and airflow continuously change what odor plumes an animal encounters and little is known about the effect one plume has on the detection of another. Using the simple Drosophila melanogaster larval model to study this relationship we identify an unexpected phenomenon: response to an attractant can be selectively blocked by previous exposure to some odorants that activates the same receptor. At a mechanistic level, we find that exposure to this type of odorant causes prolonged tonic responses from a receptor (Or42b), which can block subsequent detection of a strong activator of that same receptor. We identify naturally occurring odorants with prolonged tonic responses for other odorant receptors (Ors) as well, suggesting that termination-kinetics is a factor for olfactory coding mechanisms. This mechanism has implications for odor-coding in any system and for designing applications to modify odor-driven behaviors. PMID:26830661

  15. Olfactory receptor genes cooperate with protocadherin genes in human extreme obesity.

    PubMed

    Mariman, Edwin C M; Szklarczyk, Radek; Bouwman, Freek G; Aller, Erik E J G; van Baak, Marleen A; Wang, Ping

    2015-07-01

    Worldwide, the incidence of obesity has increased dramatically over the past decades. More knowledge about the complex etiology of obesity is needed in order to find additional approaches for treatment and prevention. Investigating the exome sequencing data of 30 extremely obese subjects (BMI 45-65 kg/m(2)) shows that predicted damaging missense variants in olfactory receptor genes on chromosome 1q and rare predicted damaging variants in the protocadherin (PCDH) beta-cluster genes on chromosome 5q31, reported in our previous work, co-localize in subjects with extreme obesity. This implies a synergistic effect between genetic variation in these gene clusters in the predisposition to extreme obesity. Evidence for a general involvement of the olfactory transduction pathway on itself could not be found. Bioinformatic analysis indicates a specific involvement of the PCDH beta-cluster genes in controlling tissue development. Further mechanistic insight needs to await the identification of the ligands of the 1q olfactory receptors. Eventually, this may provide the possibility to manipulate food flavor in a way to reduce the risk of overeating and of extreme obesity in genetically predisposed subjects.

  16. Responsiveness of the olfactory receptor cells in dog to some odors.

    PubMed

    Tonosaki, K; Tucker, D

    1985-01-01

    A preparation has been developed in the dog which allows recording the electrical activity from an olfactory nerve twig containing the axons of a small group of olfactory receptor cells. The dog's response to n-pentyl acetate is vigorous and stable, like that of other air-breathing animals. The dog's response magnitude dependence on the nasal flow rate was noticeable for n-pentyl acetates, but not so great as for n-butyric acid. The response to n-butyric acid strongly depends on the nasal flow. The start of the nasal air flow caused an increase of neural activity, which is called flow response. The results show that the nasal flow rate is a very important factor which determines the response to odors. Methyl p-hydroxybenzoate is known as a dog's pheromone, however, this odor caused the feeble response in the electrical activity of the dog's olfactory receptor cells. The differences may be dependent on several factors. PMID:2859958

  17. Partitioning non-linearities in the response of honey bee olfactory receptor neurons to binary odors.

    PubMed

    Getz, W M; Akers, R P

    1995-01-01

    In many organisms, of which honey bees are one example, a general (i.e., non-pheromonal) olfactory receptor neuron may respond to some odorants by increasing its firing rate and to others by decreasing its firing rate. In the latter case, this decrease will be with respect to a background firing rate determined by intrinsic (internal noise) and extrinsic (background odors) factors. To analyse receptor neurons of this complexity, we extend Beidler's model of receptor protein activation dynamics to account for the competition between depolarizing and hyperpolarizing pathways and couple the model to a phenomenological description of the non-linear relationship between the proportion of activate membrane receptors and the receptor cell spike generation rates. We then examine the implications of this theory for predicting the response of receptor neurons to odor mixtures based on their response to pure odorants at concentrations matched to the mixture. We derive inequalities that must be satisfied under our normative model, and propose that deviations from the model be designated as synergisms and inhibitions, depending on the direction in which various equalities and inequalities are violated. We then apply our inequalities to identifying synergisms and inhibitions in data analysed in a different way elsewhere (Akers, R.P. and Getz, W.M. Response of olfactory receptor neurons in honey bees to odorants and their binary mixtures. J. Comp. Physiol. (in press)). In these data regarding the response of honey bee placode sensilla to a number of odorants and their binary combinations, we demonstrate the presence of synergisms and inhibitions--that is, elevated or repressed responses that are not due to competitive interactions of mixture component odorants for receptor sites or Beidler (Beidler, L.M., 1962. Taste receptor stimulation. Prog. Biophys. Biophys. Chem. 12, 107-151) saturation mechanisms. PMID:7727704

  18. Leptin and its receptors are present in the rat olfactory mucosa and modulated by the nutritional status.

    PubMed

    Baly, Christine; Aioun, Josiane; Badonnel, Karine; Lacroix, Marie-Christine; Durieux, Didier; Schlegel, Claire; Salesse, Roland; Caillol, Monique

    2007-01-19

    Leptin is an adipocyte-derived cytokine that regulates body weight mainly via the long form of the leptin receptor (Ob-Rb). Leptin and its receptors are expressed in several tissues, suggesting that leptin might also be effective peripherally. We hypothesized that, as shown in taste cells, leptin and its receptors isoforms (Ob-Rs) could be present in the rat olfactory mucosa (OM). Using RT-PCR, light and electron microscopy immunohistochemistry (ICC), we found that different isoforms of the receptor were expressed in OM and localized in sustentacular cells and in a subpopulation of maturating neurons; in addition, immunoreactivity was also present in differentiated neurons and enriched at the cilia membranes, where the odorants bind to their receptors. Moreover, using RT-PCR, ICC and RIA measurements, we showed that leptin is synthesized locally in the olfactory mucosa. In addition, we demonstrate that fasting causes a significant enhanced transcription of both leptin and Ob-Rs in rat OM by quantitative RT-PCR data. Altogether, these results strongly suggested that leptin, acting as an endocrine or a paracrine factor, could be an important regulator of olfactory function, as a neuromodulator of the olfactory message in cilia of mature olfactory receptors neurons (ORN), but also for the homeostasis of this complex tissue, acting on differentiating neurons and on sustentacular cells.

  19. Enhancer interaction networks as a means for singular olfactory receptor expression

    PubMed Central

    Markenscoff-Papadimitriou, Eirene; Allen, William E.; Colquitt, Bradley M.; Goh, Tracie; Murphy, Karl K.; Monahan, Kevin; Mosley, Colleen P.; Ahituv, Nadav; Lomvardas, Stavros

    2014-01-01

    Summary The transcriptional activation of one out of ~2800 olfactory receptor (OR) alleles is a poorly understood process. Here, we identify a plethora of putative OR enhancers and study their in vivo activity in olfactory neurons. Distinguished by an unusual epigenetic signature, candidate OR enhancers are characterized by extensive interchromosomal interactions associated with OR transcription and share the similar pattern of transcription factor footprints. In particular, we establish the role of the transcription factor Bptf as a facilitator of both enhancer interactions and OR transcription. Our observations agree with the model whereby OR transcription occurs in the context of multiple interacting enhancers. Disruption of these interchromosomal interactions results in weak and multigenic OR expression, suggesting that the rare coincidence of numerous enhancers over a stochastically chosen OR may account for the singularity and robustness in OR transcription. PMID:25417106

  20. Co-opting the unfolded protein response to elicit olfactory receptor feedback

    PubMed Central

    Dalton, Ryan P.; Lyons, David B.

    2013-01-01

    Summary Olfactory receptor (OR) expression requires the transcriptional activation of one out of thousands of OR alleles and a feedback signal that preserves this transcriptional choice. The mechanism by which olfactory sensory neurons (OSNs) detect ORs to signal to the nucleus remains elusive. Here, we show that OR proteins generate this feedback by activating the unfolded protein response (UPR). OR expression induces Perk-mediated phosphorylation of the translation initiation factor eif2α causing selective translation of Activating Transcription Factor 5 (ATF5). ATF5 induces the transcription of Adenylyl Cyclase 3 (Adcy3), which relieves the UPR. Our data provide a novel role for the UPR in defining neuronal identity and cell fate commitment and support a two-step model for the feedback signal: first OR protein, as a stress stimulus, alters the translational landscape of the OSN and induces Adcy3 expression; then, Adcy3 relieves that stress, restores global translation and makes OR choice permanent. PMID:24120133

  1. Evidence for adaptive evolution of olfactory receptor genes in 9 bird species.

    PubMed

    Steiger, Silke S; Fidler, Andrew E; Mueller, Jakob C; Kempenaers, Bart

    2010-01-01

    It has been suggested that positive selection, in particular selection favoring a change in the protein sequence, plays a role in the evolution of olfactory receptor (OR) gene repertoires in fish and mammals. ORs are 7-transmembrane domain (TM) proteins, members of the G-protein-coupled receptor superfamily in vertebrate genomes, and responsible for odorant binding and discrimination. OR gene repertoires in birds are surprisingly large and diverse, suggesting that birds have a keen olfactory sense. The aim of this study is to investigate signatures of positive selection in an expanded OR clade (group-gamma-c) that seems to be a characteristic of avian genomes. Using maximum-likelihood methods that estimate the d(N)/d(S) ratios and account for the effects of recombination, we show here that there is evidence for positive selection in group-gamma-c partial OR coding sequences of 9 bird species that are likely to have different olfactory abilities: the blue tit (Cyanistes caeruleus), the black coucal (Centropus grillii), the brown kiwi (Apteryx australis), the canary (Serinus canaria), the galah (Eolophus roseicapillus), the kakapo (Strigops habroptilus), the mallard (Anas platyrhynchos), the red jungle fowl (Gallus gallus), and the snow petrel (Pagodroma nivea). Positively selected codons were predominantly located in TMs, which in other vertebrates are involved in odorant binding. Our data suggest that 1) at least some avian OR genes have been subjected to adaptive evolution, 2) the extent of such adaptive evolution differs between bird species, and 3) positive selective pressures may have been stronger on the group-gamma-c OR genes of species that have well-developed olfactory abilities. PMID:19965911

  2. Modulation by cyclic GMP of the odour sensitivity of vertebrate olfactory receptor cells

    NASA Technical Reports Server (NTRS)

    Leinders-Zufall, T.; Shepherd, G. M.; Zufall, F.

    1996-01-01

    Recent evidence has indicated a significant role for the cGMP second messenger system in vertebrate olfactory transduction but no clear functions have been identified for cGMP so far. Here, we have examined the effects of 8-Br-cGMP and carbon monoxide (CO) on odour responses of salamander olfactory receptor neurons using perforated patch recordings. We report that 8-Br-cGMP strongly down-regulates the odour sensitivity of the cells, with a K1/2 of 460 nM. This adaptation-like effect can be mimicked by CO, an activator of soluble guanylyl cyclase, with a K1/2 of 1 microM. Sensitivity modulation is achieved through a regulatory chain of events in which cGMP stimulates a persistent background current due to the activation of cyclic nucleotide-gated channels. This in turn leads to sustained Ca2+ entry providing a negative feedback signal. One consequence of the Ca2+ entry is a shift to the right of the stimulus-response curve and a reduction in saturating odour currents. Together, these two effects can reduce the sensory generator current by up to twenty-fold. Thus, cGMP functions to control the gain of the G-protein coupled cAMP pathway. Another consequence of the action of cGMP is a marked prolongation of the odour response kinetics. The effects of CO/cGMP are long-lasting and can continue for minutes. Hence, we propose that cGMP helps to prevent saturation of the cell's response by adjusting the operational range of the cAMP cascade and contributes to olfactory adaptation by decreasing the sensitivity of olfactory receptor cells to repeated odour stimuli.

  3. Supersensitive detection and discrimination of enantiomers by dorsal olfactory receptors: evidence for hierarchical odour coding.

    PubMed

    Sato, Takaaki; Kobayakawa, Reiko; Kobayakawa, Ko; Emura, Makoto; Itohara, Shigeyoshi; Kizumi, Miwako; Hamana, Hiroshi; Tsuboi, Akio; Hirono, Junzo

    2015-09-11

    Enantiomeric pairs of mirror-image molecular structures are difficult to resolve by instrumental analyses. The human olfactory system, however, discriminates (-)-wine lactone from its (+)-form rapidly within seconds. To gain insight into receptor coding of enantiomers, we compared behavioural detection and discrimination thresholds of wild-type mice with those of ΔD mice in which all dorsal olfactory receptors are genetically ablated. Surprisingly, wild-type mice displayed an exquisite "supersensitivity" to enantiomeric pairs of wine lactones and carvones. They were capable of supersensitive discrimination of enantiomers, consistent with their high detection sensitivity. In contrast, ΔD mice showed selective major loss of sensitivity to the (+)-enantiomers. The resulting 10(8)-fold differential sensitivity of ΔD mice to (-)- vs. (+)-wine lactone matched that observed in humans. This suggests that humans lack highly sensitive orthologous dorsal receptors for the (+)-enantiomer, similarly to ΔD mice. Moreover, ΔD mice showed >10(10)-fold reductions in enantiomer discrimination sensitivity compared to wild-type mice. ΔD mice detected one or both of the (-)- and (+)-enantiomers over a wide concentration range, but were unable to discriminate them. This "enantiomer odour discrimination paradox" indicates that the most sensitive dorsal receptors play a critical role in hierarchical odour coding for enantiomer identification.

  4. Odorant-induced Responses Recorded from Olfactory Receptor Neurons using the Suction Pipette Technique

    PubMed Central

    Matthews, Hugh R.; Reisert, Johannes

    2012-01-01

    Animals sample the odorous environment around them through the chemosensory systems located in the nasal cavity. Chemosensory signals affect complex behaviors such as food choice, predator, conspecific and mate recognition and other socially relevant cues. Olfactory receptor neurons (ORNs) are located in the dorsal part of the nasal cavity embedded in the olfactory epithelium. These bipolar neurons send an axon to the olfactory bulb (see Fig. 1, Reisert & Zhao1, originally published in the Journal of General Physiology) and extend a single dendrite to the epithelial border from where cilia radiate into the mucus that covers the olfactory epithelium. The cilia contain the signal transduction machinery that ultimately leads to excitatory current influx through the ciliary transduction channels, a cyclic nucleotide-gated (CNG) channel and a Ca2+-activated Cl- channel (Fig. 1). The ensuing depolarization triggers action potential generation at the cell body2-4. In this video we describe the use of the "suction pipette technique" to record odorant-induced responses from ORNs. This method was originally developed to record from rod photoreceptors5 and a variant of this method can be found at jove.com modified to record from mouse cone photoreceptors6. The suction pipette technique was later adapted to also record from ORNs7,8. Briefly, following dissociation of the olfactory epithelium and cell isolation, the entire cell body of an ORN is sucked into the tip of a recording pipette. The dendrite and the cilia remain exposed to the bath solution and thus accessible to solution changes to enable e.g. odorant or pharmacological blocker application. In this configuration, no access to the intracellular environment is gained (no whole-cell voltage clamp) and the intracellular voltage remains free to vary. This allows the simultaneous recording of the slow receptor current that originates at the cilia and fast action potentials fired by the cell body9. The difference in

  5. Loss of olfactory receptor genes coincides with the acquisition of full trichromatic vision in primates.

    PubMed

    Gilad, Yoav; Wiebe, Victor; Przeworski, Molly; Lancet, Doron; Pääbo, Svante

    2004-01-01

    Olfactory receptor (OR) genes constitute the molecular basis for the sense of smell and are encoded by the largest gene family in mammalian genomes. Previous studies suggested that the proportion of pseudogenes in the OR gene family is significantly larger in humans than in other apes and significantly larger in apes than in the mouse. To investigate the process of degeneration of the olfactory repertoire in primates, we estimated the proportion of OR pseudogenes in 19 primate species by surveying randomly chosen subsets of 100 OR genes from each species. We find that apes, Old World monkeys and one New World monkey, the howler monkey, have a significantly higher proportion of OR pseudogenes than do other New World monkeys or the lemur (a prosimian). Strikingly, the howler monkey is also the only New World monkey to possess full trichromatic vision, along with Old World monkeys and apes. Our findings suggest that the deterioration of the olfactory repertoire occurred concomitant with the acquisition of full trichromatic color vision in primates. PMID:14737185

  6. Odorant receptors regulate the final glomerular coalescence of olfactory sensory neuron axons

    PubMed Central

    Rodriguez-Gil, Diego J.; Bartel, Dianna L.; Jaspers, Austin W.; Mobley, Arie S.; Imamura, Fumiaki; Greer, Charles A.

    2015-01-01

    Odorant receptors (OR) are strongly implicated in coalescence of olfactory sensory neuron (OSN) axons and the formation of olfactory bulb (OB) glomeruli. However, when ORs are first expressed relative to basal cell division and OSN axon extension is unknown. We developed an in vivo fate-mapping strategy that enabled us to follow OSN maturation and axon extension beginning at basal cell division. In parallel, we mapped the molecular development of OSNs beginning at basal cell division, including the onset of OR expression. Our data show that ORs are first expressed around 4 d following basal cell division, 24 h after OSN axons have reached the OB. Over the next 6+ days the OSN axons navigate the OB nerve layer and ultimately coalesce in glomeruli. These data provide a previously unidentified perspective on the role of ORs in homophilic OSN axon adhesion and lead us to propose a new model dividing axon extension into two phases. Phase I is OR-independent and accounts for up to 50% of the time during which axons approach the OB and begin navigating the olfactory nerve layer. Phase II is OR-dependent and concludes as OSN axons coalesce in glomeruli. PMID:25902488

  7. Odorant receptors regulate the final glomerular coalescence of olfactory sensory neuron axons.

    PubMed

    Rodriguez-Gil, Diego J; Bartel, Dianna L; Jaspers, Austin W; Mobley, Arie S; Imamura, Fumiaki; Greer, Charles A

    2015-05-01

    Odorant receptors (OR) are strongly implicated in coalescence of olfactory sensory neuron (OSN) axons and the formation of olfactory bulb (OB) glomeruli. However, when ORs are first expressed relative to basal cell division and OSN axon extension is unknown. We developed an in vivo fate-mapping strategy that enabled us to follow OSN maturation and axon extension beginning at basal cell division. In parallel, we mapped the molecular development of OSNs beginning at basal cell division, including the onset of OR expression. Our data show that ORs are first expressed around 4 d following basal cell division, 24 h after OSN axons have reached the OB. Over the next 6+ days the OSN axons navigate the OB nerve layer and ultimately coalesce in glomeruli. These data provide a previously unidentified perspective on the role of ORs in homophilic OSN axon adhesion and lead us to propose a new model dividing axon extension into two phases. Phase I is OR-independent and accounts for up to 50% of the time during which axons approach the OB and begin navigating the olfactory nerve layer. Phase II is OR-dependent and concludes as OSN axons coalesce in glomeruli.

  8. Transduction in Drosophila olfactory receptor neurons is invariant to air speed

    PubMed Central

    Zhou, Yi

    2012-01-01

    In the vertebrate nose, increasing air speed tends to increase the magnitude of odor-evoked activity in olfactory receptor neurons (ORNs), given constant odor concentration and duration. It is often assumed that the same is true of insect olfactory organs, but this has not been directly tested. In this study, we examined the effect of air speed on ORN responses in Drosophila melanogaster. We constructed an odor delivery device that allowed us to independently vary concentration and air speed, and we used a fast photoionization detector to precisely measure the actual odor concentration at the antenna while simultaneously recording spikes from ORNs in vivo. Our results demonstrate that Drosophila ORN odor responses are invariant to air speed, as long as odor concentration is kept constant. This finding was true across a >100-fold range of air speeds. Because odor hydrophobicity has been proposed to affect the air speed dependence of olfactory transduction, we tested a >1,000-fold range of hydrophobicity values and found that ORN responses are invariant to air speed across this full range. These results have implications for the mechanisms of odor delivery to Drosophila ORNs. Our findings are also significant because flies have a limited ability to control air flow across their antennae, unlike terrestrial vertebrates, which can control air flow within their nasal cavity. Thus, for the fly, invariance to air speed may be adaptive because it confers robustness to changing wind conditions. PMID:22815404

  9. Ca(2+)-BK channel clusters in olfactory receptor neurons and their role in odour coding.

    PubMed

    Bao, Guobin; de Jong, Daniëlle; Alevra, Mihai; Schild, Detlev

    2015-12-01

    Olfactory receptor neurons (ORNs) have high-voltage-gated Ca(2+) channels whose physiological impact has remained enigmatic since the voltage-gated conductances in this cell type were first described in the 1980s. Here we show that in ORN somata of Xenopus laevis tadpoles these channels are clustered and co-expressed with large-conductance potassium (BK) channels. We found approximately five clusters per ORN and twelve Ca(2+) channels per cluster. The action potential-triggered activation of BK channels accelerates the repolarization of action potentials and shortens interspike intervals during odour responses. This increases the sensitivity of individual ORNs to odorants. At the level of mitral cells of the olfactory bulb, odour qualities have been shown to be coded by first-spike-latency patterns. The system of Ca(2+) and BK channels in ORNs appears to be important for correct odour coding because the blockage of BK channels not only affects ORN spiking patterns but also changes the latency pattern representation of odours in the olfactory bulb.

  10. Chemosensory signals and their receptors in the olfactory neural system.

    PubMed

    Ihara, S; Yoshikawa, K; Touhara, K

    2013-12-19

    Chemical communication is widely used among various organisms to obtain essential information from their environment required for life. Although a large variety of molecules have been shown to act as chemical cues, the molecular and neural basis underlying the behaviors elicited by these molecules has been revealed for only a limited number of molecules. Here, we review the current knowledge regarding the signaling molecules whose flow from receptor to specific behavior has been characterized. Discussing the molecules utilized by mice, insects, and the worm, we focus on how each organism has optimized its reception system to suit its living style. We also highlight how the production of these signaling molecules is regulated, an area in which considerable progress has been recently made.

  11. Calcium-stores mediate adaptation in axon terminals of Olfactory Receptor Neurons in Drosophila

    PubMed Central

    2011-01-01

    Background In vertebrates and invertebrates, sensory neurons adapt to variable ambient conditions, such as the duration or repetition of a stimulus, a physiological mechanism considered as a simple form of non-associative learning and neuronal plasticity. Although various signaling pathways, as cAMP, cGMP, and the inositol 1,4,5-triphosphate receptor (InsP3R) play a role in adaptation, their precise mechanisms of action at the cellular level remain incompletely understood. Recently, in Drosophila, we reported that odor-induced Ca2+-response in axon terminals of olfactory receptor neurons (ORNs) is related to odor duration. In particular, a relatively long odor stimulus (such as 5 s) triggers the induction of a second component involving intracellular Ca2+-stores. Results We used a recently developed in-vivo bioluminescence imaging approach to quantify the odor-induced Ca2+-activity in the axon terminals of ORNs. Using either a genetic approach to target specific RNAs, or a pharmacological approach, we show that the second component, relying on the intracellular Ca2+-stores, is responsible for the adaptation to repetitive stimuli. In the antennal lobes (a region analogous to the vertebrate olfactory bulb) ORNs make synaptic contacts with second-order neurons, the projection neurons (PNs). These synapses are modulated by GABA, through either GABAergic local interneurons (LNs) and/or some GABAergic PNs. Application of GABAergic receptor antagonists, both GABAA or GABAB, abolishes the adaptation, while RNAi targeting the GABABR (a metabotropic receptor) within the ORNs, blocks the Ca2+-store dependent component, and consequently disrupts the adaptation. These results indicate that GABA exerts a feedback control. Finally, at the behavioral level, using an olfactory test, genetically impairing the GABABR or its signaling pathway specifically in the ORNs disrupts olfactory adapted behavior. Conclusion Taken together, our results indicate that a relatively long lasting

  12. Interactions of odorants with olfactory receptors and receptor neurons match the perceptual dynamics observed for woody and fruity odorant mixtures.

    PubMed

    Chaput, M A; El Mountassir, F; Atanasova, B; Thomas-Danguin, T; Le Bon, A M; Perrut, A; Ferry, B; Duchamp-Viret, P

    2012-02-01

    The present study aimed to create a direct bridge between observations on peripheral and central responses to odorant mixtures and their components. Three experiments were performed using mixtures of fruity (isoamyl acetate; ISO) and woody (whiskey lactone; WL) odorants known to contribute to some of the major notes in Burgundy red wine. These experiments consisted of (i) calcium imaging of human embryonic kidney cells (HEK293T) transfected with olfactory receptors (ORs); (ii) single-unit electrophysiological recordings from olfactory receptor neurons (ORNs) and analyses of electro-olfactogram (EOG) responses in the rat nose in vivo; and (iii) psychophysical measurements of the perceived intensity of the mixtures as rated by human subjects. The calcium imaging and electrophysiological results revealed that ISO and WL can act simultaneously on single ORs or ORNs and confirm that receptor responses to mixtures are not the result of a simple sum of the effects of the individual mixture compounds. The addition of WL to ISO principally suppressed the ORN activation induced by ISO alone and was found to enhance this activation in a subset of cases. In the human studies, the addition of high concentrations of WL to ISO decreased the perceived intensity of the ISO. In contrast, the addition of low concentrations of WL enhanced the perceived intensity of the fruity note (ISO) in this mixture, as it enhanced EOG responses in ORNs. Thus, both OR and ORN responses to ISO + WL mixtures faithfully reflected perceptual response changes, so the odour mixture information is set up after the peripheral stage of the olfactory system.

  13. Interactions of odorants with olfactory receptors and receptor neurons match the perceptual dynamics observed for woody and fruity odorant mixtures.

    PubMed

    Chaput, M A; El Mountassir, F; Atanasova, B; Thomas-Danguin, T; Le Bon, A M; Perrut, A; Ferry, B; Duchamp-Viret, P

    2012-02-01

    The present study aimed to create a direct bridge between observations on peripheral and central responses to odorant mixtures and their components. Three experiments were performed using mixtures of fruity (isoamyl acetate; ISO) and woody (whiskey lactone; WL) odorants known to contribute to some of the major notes in Burgundy red wine. These experiments consisted of (i) calcium imaging of human embryonic kidney cells (HEK293T) transfected with olfactory receptors (ORs); (ii) single-unit electrophysiological recordings from olfactory receptor neurons (ORNs) and analyses of electro-olfactogram (EOG) responses in the rat nose in vivo; and (iii) psychophysical measurements of the perceived intensity of the mixtures as rated by human subjects. The calcium imaging and electrophysiological results revealed that ISO and WL can act simultaneously on single ORs or ORNs and confirm that receptor responses to mixtures are not the result of a simple sum of the effects of the individual mixture compounds. The addition of WL to ISO principally suppressed the ORN activation induced by ISO alone and was found to enhance this activation in a subset of cases. In the human studies, the addition of high concentrations of WL to ISO decreased the perceived intensity of the ISO. In contrast, the addition of low concentrations of WL enhanced the perceived intensity of the fruity note (ISO) in this mixture, as it enhanced EOG responses in ORNs. Thus, both OR and ORN responses to ISO + WL mixtures faithfully reflected perceptual response changes, so the odour mixture information is set up after the peripheral stage of the olfactory system. PMID:22304504

  14. Study of a synthetic human olfactory receptor 17-4: expression and purification from an inducible mammalian cell line.

    PubMed

    Cook, Brian L; Ernberg, Karin E; Chung, Hyeyoun; Zhang, Shuguang

    2008-01-01

    In order to begin to study the structural and functional mechanisms of olfactory receptors, methods for milligram-scale purification are required. Here we demonstrate the production and expression of a synthetically engineered human olfactory receptor hOR17-4 gene in a stable tetracycline-inducible mammalian cell line (HEK293S). The olfactory receptor gene was fabricated from scratch using PCR-based gene-assembly, which facilitated codon optimization and attachment of a 9-residue bovine rhodopsin affinity tag for detection and purification. Induction of adherent cultures with tetracycline together with sodium butyrate led to hOR17-4 expression levels of approximately 30 microg per 150 mm tissue culture plate. Fos-choline-based detergents proved highly capable of extracting the receptors, and fos-choline-14 (N-tetradecylphosphocholine) was selected for optimal solubilization and subsequent purification. Analysis by SDS-PAGE revealed both monomeric and dimeric receptor forms, as well as higher MW oligomeric species. A two-step purification method of immunoaffinity and size exclusion chromatography was optimized which enabled 0.13 milligrams of hOR17-4 monomer to be obtained at >90% purity. This high purity of hOR17-4 is not only suitable for secondary structural and functional analyses but also for subsequent crystallization trials. Thus, this system demonstrates the feasibility of purifying milligram quantities of the GPCR membrane protein hOR17-4 for fabrication of olfactory receptor-based bionic sensing device.

  15. Non-conventional mesons at PANDA

    NASA Astrophysics Data System (ADS)

    Giacosa, Francesco

    2015-04-01

    Non-conventional mesons, such as glueballs and tetraquarks, will be in the focus of the PANDA experiment at the FAIR facility. In this lecture we recall the basic properties of QCD and describe some features of unconventional states. We focus on the search of the not-yet discovered glueballs and the use of the extended Linear Sigma Model for this purpose, and on the already discovered but not-yet understood X, Y, Z states.

  16. Underlying mathematics in diversification of human olfactory receptors in different loci.

    PubMed

    Hassan, Sk Sarif; Choudhury, Pabitra Pal; Goswami, Arunava

    2013-12-01

    As per conservative estimate, approximately 51-105 Olfactory Receptors (ORs) loci are present in human genome occurring in clusters. These clusters are apparently unevenly spread as mosaics over 21 pairs of human chromosomes. Olfactory Receptor (OR) gene families which are thought to have expanded for the need to provide recognition capability for a huge number of pure and complex odorants, form the largest known multigene family in the human genome. Recent studies have shown that 388 full length and 414 OR pseudo-genes are present in these OR genomic clusters. In this paper, the authors report a classification method for all human ORs based on their sequential quantitative information like presence of poly strings of nucleotides bases, long range correlation and so on. An L-System generated sequence has been taken as an input into a star-model of specific subfamily members and resultant sequence has been mapped to a specific OR based on the classification scheme using fractal parameters like Hurst exponent and fractal dimensions.

  17. Olfactory conditioning impairment following posttraining NMDA receptor blockade in neonatal rats.

    PubMed

    Weldon, D A; Fedorcik, G G; LoRusso, C M; Tiburzi, M J; Lenoci, J M

    1997-01-01

    Six-day-old Sprague-Dawley rat pups were exposed to peppermint odor paired with tactile stimulation (stroking the skin with a paint brush) for twenty 10-s conditioning trials, and their olfactory preference was tested the next day. In Experiment 1, pups that had received an injection of the noncompetitive N-methyl-D-aspartate receptor antagonist MK-801 (0.1 mg/kg, i.p.) either 30 min before or immediately after conditioning spent less time over the conditioned odor than saline-treated controls. In Experiment 2, pups received an injection of either MK-801 or saline 0, 30, or 60 min after the training period. There was a reduction in the preference for the conditioned odor in the animals receiving MK-801 immediately following training, but treatment with the drug at the other intervals did not produce a performance impairment. The impairment following immediate posttraining injection occurred with either 0.05 or 0.1, but not with 0.01 mg/kg of MK-801 (Experiment 3). Experiment 4 provided control data to confirm that pups that had experienced the procedures used in Experiments 1-3 showed greater preference for the conditioned odor than did naive pups or those receiving exposure to the odor without stroking. The data indicate that immediate posttraining activation of N-methyl-D-aspartate receptors is required for normal olfactory learning in neonatal rats. PMID:9013499

  18. G protein-coupled odorant receptors underlie mechanosensitivity in mammalian olfactory sensory neurons

    PubMed Central

    Connelly, Timothy; Yu, Yiqun; Grosmaitre, Xavier; Wang, Jue; Santarelli, Lindsey C.; Savigner, Agnes; Qiao, Xin; Wang, Zhenshan; Storm, Daniel R.; Ma, Minghong

    2015-01-01

    Mechanosensitive cells are essential for organisms to sense the external and internal environments, and a variety of molecules have been implicated as mechanical sensors. Here we report that odorant receptors (ORs), a large family of G protein-coupled receptors, underlie the responses to both chemical and mechanical stimuli in mouse olfactory sensory neurons (OSNs). Genetic ablation of key signaling proteins in odor transduction or disruption of OR–G protein coupling eliminates mechanical responses. Curiously, OSNs expressing different OR types display significantly different responses to mechanical stimuli. Genetic swap of putatively mechanosensitive ORs abolishes or reduces mechanical responses of OSNs. Furthermore, ectopic expression of an OR restores mechanosensitivity in loss-of-function OSNs. Lastly, heterologous expression of an OR confers mechanosensitivity to its host cells. These results indicate that certain ORs are both necessary and sufficient to cause mechanical responses, revealing a previously unidentified mechanism for mechanotransduction. PMID:25550517

  19. Haloferax volcanii, as a Novel Tool for Producing Mammalian Olfactory Receptors Embedded in Archaeal Lipid Bilayer

    PubMed Central

    Lobasso, Simona; Vitale, Rita; Lopalco, Patrizia; Corcelli, Angela

    2015-01-01

    The aim of this study was to explore the possibility of using an archaeal microorganism as a host system for expressing mammalian olfactory receptors (ORs). We have selected the archaeon Haloferax volcanii as a cell host system and one of the most extensively investigated OR, namely I7-OR, whose preferred ligands are short-chain aldehydes, such as octanal, heptanal, nonanal. A novel plasmid has been constructed to express the rat I7-OR, fused with a hexahistidine-tag for protein immunodetection. The presence of the recombinant receptor at a membrane level was demonstrated by immunoblot of the membranes isolated from the transgenic archaeal strain. In addition, the lipid composition of archaeonanosomes containing ORs has been characterized in detail by High-Performance Thin-Layer Chromatography (HPTLC) in combination with Matrix-Assisted Laser Desorption Ionization—Time-Of-Flight/Mass Spectrometry (MALDI-TOF/MS) analysis. PMID:25761264

  20. Deciphering activation of olfactory receptors using heterologous expression in Saccharomyces cerevisiae and bioluminescence resonance energy transfer.

    PubMed

    Sanz, Guenhaël; Pajot-Augy, Edith

    2013-01-01

    Hetero- and homo-oligomerization of G protein-coupled receptors (GPCRs) has been addressed in the past years using various approaches such as co-immunoprecipitation, fluorescence resonance energy transfer and bioluminescence resonance energy transfer (BRET). Here, we report the methodological details from a previously published study to investigate the relationships between oligomerization and activation states of olfactory receptors (ORs). This methodology combines heterologous expression of ORs in Saccharomyces cerevisiae and BRET assays on membrane fractions, in particular, upon odorant stimulation. We have demonstrated that ORs constitutively homodimerize at the plasma membrane and that high odorant concentrations promote a conformational change of the dimer, which becomes inactive. We proposed a model in which one odorant molecule binding the dimer would induce activation, while two odorant molecules, each binding one protomer of the dimer, would blunt signaling.

  1. Cyclic-nucleotide–gated cation current and Ca2+-activated Cl current elicited by odorant in vertebrate olfactory receptor neurons

    PubMed Central

    Li, Rong-Chang; Ben-Chaim, Yair; Yau, King-Wai; Lin, Chih-Chun

    2016-01-01

    Olfactory transduction in vertebrate olfactory receptor neurons (ORNs) involves primarily a cAMP-signaling cascade that leads to the opening of cyclic-nucleotide–gated (CNG), nonselective cation channels. The consequent Ca2+ influx triggers adaptation but also signal amplification, the latter by opening a Ca2+-activated Cl channel (ANO2) to elicit, unusually, an inward Cl current. Hence the olfactory response has inward CNG and Cl components that are in rapid succession and not easily separable. We report here success in quantitatively separating these two currents with respect to amplitude and time course over a broad range of odorant strengths. Importantly, we found that the Cl current is the predominant component throughout the olfactory dose–response relation, down to the threshold of signaling to the brain. This observation is very surprising given a recent report by others that the olfactory-signal amplification effected by the Ca2+-activated Cl current does not influence the behavioral olfactory threshold in mice. PMID:27647918

  2. Immunochemical strategy for quantification of G-coupled olfactory receptor proteins on natural nanovesicles.

    PubMed

    Sanmartí-Espinal, Marta; Galve, Roger; Iavicoli, Patrizia; Persuy, Marie-Annick; Pajot-Augy, Edith; Marco, M-Pilar; Samitier, Josep

    2016-03-01

    Cell membrane proteins are involved in a variety of biochemical pathways and therefore constitute important targets for therapy and development of new drugs. Bioanalytical platforms and binding assays using these membrane protein receptors for drug screening or diagnostic require the construction of well-characterized liposome and lipid bilayer arrays that act as support to prevent protein denaturation during biochip processing. Quantification of the protein receptors in the lipid membrane arrays is a key issue in order to produce reproducible and well-characterized chips. Herein, we report a novel immunochemical analytical approach for the quantification of membrane proteins (i.e., G-protein-coupled receptor, GPCR) in nanovesicles (NVs). The procedure allows direct determination of tagged receptors (i.e., c-myc tag) without any previous protein purification or extraction steps. The immunochemical method is based on a microplate ELISA format and quantifies this tag on proteins embedded in NVs with detectability in the picomolar range, using protein bioconjugates as reference standards. The applicability of the method is demonstrated through the quantification of the c-myc-olfactory receptor (OR, c-myc-OR1740) in the cell membrane NVs. The reported method opens the possibility to develop well-characterized drug-screening platforms based on G-coupled proteins embedded on membranes.

  3. Linear correlation between the number of olfactory sensory neurons expressing a given mouse odorant receptor gene and the total volume of the corresponding glomeruli in the olfactory bulb

    PubMed Central

    Bressel, Olaf Christian; Khan, Mona

    2015-01-01

    ABSTRACT Chemosensory specificity in the main olfactory system of the mouse relies on the expression of ∼1,100 odorant receptor (OR) genes across millions of olfactory sensory neurons (OSNs) in the main olfactory epithelium (MOE), and on the coalescence of OSN axons into ∼3,600 glomeruli in the olfactory bulb. A traditional approach for visualizing OSNs and their axons consists of tagging an OR gene genetically with an axonal marker that is cotranslated with the OR by virtue of an internal ribosome entry site (IRES). Here we report full cell counts for 15 gene‐targeted strains of the OR‐IRES‐marker design coexpressing a fluorescent protein. These strains represent 11 targeted OR genes, a 1% sample of the OR gene repertoire. We took an empirical, “count every cell” strategy: we counted all fluorescent cell profiles with a nuclear profile within the cytoplasm, on all serial coronal sections under a confocal microscope, a total of 685,673 cells in 56 mice at postnatal day 21. We then applied a strain‐specific Abercrombie correction to these OSN counts in order to obtain a closer approximation of the true OSN numbers. We found a 17‐fold range in the average (corrected) OSN number across these 11 OR genes. In the same series of coronal sections, we then determined the total volume of the glomeruli (TGV) formed by coalescence of the fluorescent axons. We found a strong linear correlation between OSN number and TGV, suggesting that TGV can be used as a surrogate measurement for estimating OSN numbers in these gene‐targeted strains. J. Comp. Neurol. 524:199–209, 2016. © 2015 Wiley Periodicals, Inc. PMID:26100963

  4. Identification of specific ligands for orphan olfactory receptors. G protein-dependent agonism and antagonism of odorants.

    PubMed

    Shirokova, Elena; Schmiedeberg, Kristin; Bedner, Peter; Niessen, Heiner; Willecke, Klaus; Raguse, Jan-Dirk; Meyerhof, Wolfgang; Krautwurst, Dietmar

    2005-03-25

    Olfactory receptors are the largest group of orphan G protein-coupled receptors with an infinitely small number of agonists identified out of thousands of odorants. The de-orphaning of olfactory receptor (OR) is complicated by its combinatorial odorant coding and thus requires large scale odorant and receptor screening and establishing receptor-specific odorant profiles. Here, we report on the stable reconstitution of OR-specific signaling in HeLa/Olf cells via G protein alphaolf and adenylyl cyclase type-III to the Ca2+ influx-mediating olfactory cyclic nucleotide-gated CNGA2 channel. We demonstrate the central role of Galphaolf in odorant-specific signaling out of OR. The employment of the non-typical G protein alpha15 dramatically altered the odorant specificities of 3 of 7 receptors that had been characterized previously by different groups. We further show for two OR that an odorant may be an agonist or antagonist, depending on the G protein used. HeLa/Olf cells proved suitable for high-throughput screening in fluorescence-imaging plate reader experiments, resulting in the de-orphaning of two new OR for the odorant (-)citronellal from an expression library of 93 receptors. To demonstrate the G protein dependence of its odorant response pattern, we screened the most sensitive (-)citronellal receptor Olfr43 versus 94 odorants simultaneously in the presence of Galpha15 or Galphaolf. We finally established an EC50-ranking odorant profile for Olfr43 in HeLa/Olf cells. In summary, we conclude that, in heterologous systems, odorants may function as agonists or antagonists, depending on the G protein used. HeLa/Olf cells provide an olfactory model system for functional expression and de-orphaning of OR.

  5. Olfactory discrimination of structurally related molecules: receptor cell responses to camphoraceous odorants.

    PubMed

    Sicard, G

    1985-02-11

    Electrophysiological investigations of the selective sensitivity of receptor cells have shown that odorants could be distributed into groups according to the profiles of responses that they elicited from a population of receptor cells. As the concept of odorant group plays an important role in the understanding of olfactory coding, an attempt was made to investigate in detail the group properties of a number of structurally and qualitatively related molecules: 1,8 cineole, DL-camphor, borneol, iso-borneol, adamantane, fenchone, fenchyl alcohol, 3,3,5-tri-methyl cyclohexanone, camphene, 1,1,2,2-tetra-bromoethane. These odorants, along with several other representatives of other odorant groups, were utilized to stimulate a set of 71 individually recorded receptor cells. Factor analysis of electrophysiological data demonstrated that the grouping of odorants with camphor could be predicted on the basis of the shape and size of the molecules. The analysis also showed that even a clearly defined odorant group such as the camphor group is not likely to be determined by a single type of receptor site.

  6. Functional genomics reveals dysregulation of cortical olfactory receptors in Parkinson disease: novel putative chemoreceptors in the human brain.

    PubMed

    Garcia-Esparcia, Paula; Schlüter, Agatha; Carmona, Margarita; Moreno, Jesús; Ansoleaga, Belen; Torrejón-Escribano, Benjamín; Gustincich, Stefano; Pujol, Aurora; Ferrer, Isidre

    2013-06-01

    Parkinson disease (PD) is no longer considered a complex motor disorder but rather a systemic disease with variable nonmotor deficits that may include impaired olfaction, depression, mood and sleep disorders, and altered cortical function. Increasing evidence indicates that multiple metabolic defects occur in regions outside the substantia nigra, including the cerebral cortex, even at premotor stages of the disease. We investigated changes in gene expression in the frontal cortex in PD patient brains using a transcriptomics approach. Functional genomics analysis indicated that cortical olfactory receptors (ORs) and taste receptors (TASRs) are altered in PD patients. Olfactory receptors OR2L13, OR1E1, OR2J3, OR52L1, and OR11H1 and taste receptors TAS2R5 and TAS2R50 were downregulated, but TAS2R10 and TAS2R13 were upregulated at premotor and parkinsonian stages in the frontal cortex area 8 in PD patient brains. Furthermore, we present novel evidence that, in addition to the ORs, obligate downstream components of OR function adenylyl cyclase 3 and olfactory G protein (Gαolf), OR transporters, receptor transporter proteins 1 and 2 and receptor expression enhancing protein 1, and OR xenobiotic removing UDP-glucuronosyltransferase 1 family polypeptide A6 are widely expressed in neurons of the cerebral cortex and other regions of the adult human brain. Together, these findings support the concept that ORs and TASRs in the cerebral cortex may have novel physiologic functions that are affected in PD patients.

  7. [The underwater EOG of the frog Rana temporaria to stimulation of the olfactory receptors with solutions of fragrances and amino acids].

    PubMed

    Kruzhalov, N B

    1991-01-01

    Studies have been made on the effectiveness of 16 amino acids and 9 odorants in olfactory perception of the frog Rana temporaria. It was shown that the effectiveness of amino acids is close to that of odorants. Basic amino acids and cysteine were more effective than other amino acids. Sensitivity of the olfactory receptors to amino acids in frogs is lower than in fishes.

  8. Quantitative assessment of olfactory receptors activity in immobilized nanosomes: a novel concept for bioelectronic nose.

    PubMed

    Vidic, Jasmina Minic; Grosclaude, Jeanne; Persuy, Marie-Annick; Aioun, Josiane; Salesse, Roland; Pajot-Augy, Edith

    2006-08-01

    We describe how mammalian olfactory receptors (ORs) could be used as sensing elements of highly specific and sensitive bioelectronic noses. An OR and an appropriate G(alpha) protein were co-expressed in Saccharomyces cerevisiae cells from which membrane nanosomes were prepared, and immobilized on a sensor chip. By Surface Plasmon Resonance, we were able to quantitatively evaluate OR stimulation by an odorant, and G protein activation. We demonstrate that ORs in nanosomes discriminate between odorant ligands and unrelated odorants, as in whole cells. This assay also provides the possibility for quantitative assessment of the coupling efficiency of the OR with different G(alpha) subunits, without the interference of the cellular transduction pathway. Our findings will be useful to develop a new generation of electronic noses for detection and discrimination of volatile compounds, particularly amenable to micro- and nano-sensor formats.

  9. Olfactory receptors in the melon fly Dacus cucurbitae and the oriental fruit fly Dacus dorsalis

    PubMed Central

    Metcalf, Robert L.; Mitchell, Wallace C.; Metcalf, Esther R.

    1983-01-01

    Male melon flies (Dacus cucurbitae) from a colony in Hawaii were evaluated for limit of response to the olfactory stimulant raspberry ketone and to more than 40 related molecules. The results were compared with the limits of response of oriental fruit flies (Dacus dorsalis) under identical conditions. The nature of the response of the two species to attractive compounds appeared to be identical with regard to orientation, searching, pulsating mouthparts, and compulsive feeding. However, there was very little overlap in the response of the two species to phenylpropanoid-type compounds. D. cucurbitae responded most strongly to p-hydroxyphenylpropanoids while D. dorsalis responded most strongly to 3,4-dimethoxyphenylpropanoids. The results are discussed in terms of antennal receptor site geometry and with regard to the coevolution of two major groups of Dacini with plant kairomones. Images PMID:16593321

  10. Association between olfactory receptor genes, eating behavior traits and adiposity: results from the Quebec Family Study.

    PubMed

    Choquette, Anne C; Bouchard, Luigi; Drapeau, Vicky; Lemieux, Simone; Tremblay, Angelo; Bouchard, Claude; Vohl, Marie-Claude; Pérusse, Louis

    2012-02-01

    Obesity is a major health problem that can be influenced by eating behaviors. Evidence suggests that the sensory properties of food influence eating behaviors and lead to overeating and overweight. A previous genome-wide linkage scan for eating behavior traits assessed with the Three-Factor Eating Questionnaire (cognitive dietary restraint, disinhibition and hunger) performed in the Quebec Family Study (QFS) revealed a quantitative trait locus for disinhibition on chromosome 19p13. This region encodes a cluster of seven olfactory receptor (OR) genes, including OR7D4, previously associated with odor perceptions. Direct sequencing of the OR7D4 gene revealed 16 sequence variants. Nine OR7D4 sequence variants with minor allele frequency (MAF)>1% as well as 100 SNPs spanning the cluster of OR genes on 19p13 were tested for association with age- and sex-adjusted eating behaviors as well as adiposity traits in 890 subjects. One OR7D4 sequence variant (rs2878329 G>A) showed evidence of association with reduced levels of adiposity (p=0.03), cognitive dietary restraint (p=0.05) and susceptibility to hunger (p=0.008). None of the OR7D4 SNPs was associated with disinhibition, but a SNP (rs2240927) in another OR gene (OR7E24) showed evidence of association (p=0.03). Another SNP in the OR7G3 gene (rs10414255) was also found to be associated with adiposity and eating behaviors. These results are the first to suggest that variations in human olfactory receptor genes can influence eating behaviors and adiposity. The associations reported in the present study should be interpreted with caution considering the number of tests performed and considered as potential new hypotheses about the effects OR polymorphisms on eating behaviors and obesity that need to be further explored in other populations.

  11. Olfactory sensitivity to steroid glucuronates in Mozambique tilapia suggests two distinct and specific receptors for pheromone detection.

    PubMed

    Keller-Costa, Tina; Canário, Adelino V M; Hubbard, Peter C

    2014-12-01

    Cichlids offer an exciting opportunity to understand vertebrate speciation; chemical communication could be one of the drivers of African cichlid radiation. Chemical signals mediate key aspects in the lives of vertebrates and often are species specific. Dominant male Mozambique tilapia [Oreochromis mossambicus (Peters 1852)] release a sex pheromone, 5β-pregnan-3α,17α,20β-triol 3-glucuronate and its 20α-epimer, via their urine. The objective of this study was to assess the sensitivity, specificity and versatility of the olfactory system of O. mossambicus to other steroids and their conjugates using the electro-olfactogram. Oreochromis mossambicus was sensitive to several 3-glucuronidated steroids, but did not respond to prostaglandins, unconjugated steroids or 17- or 20-conjugated steroids. Stimulation of the olfactory epithelium with increasing concentrations (1 pmol l(-1) to 10 μmol l(-1)) of 5β-pregnan-3α,17α,20β-triol 3-glucuronate, 5β-pregnan-3α,17α,20α-triol 3-glucuronate, 3α,17α-dihydroxy-5β-pregnan-20-one 3-glucuronate, etiocholanolone 3α-glucuronate and 17β-estradiol 3-glucuronate produced characteristic sigmoidal concentration-response curves. However, tilapia were most sensitive to 17β-estradiol-3-glucuronate, which also had the lowest apparent EC50 and maximal response amplitude. Cross-adaptation and binary mixture experiments suggested that 5β,3α-reduced pregnan- and androstan-3-glucuronates share (a) common olfactory receptor(s), whereas 17β-estradiol 3-glucuronate is detected via (a) distinct olfactory receptor(s). In conclusion, the Mozambique tilapia has evolved high olfactory sensitivity and specificity to 3-glucuronidated steroids through two distinct olfactory receptor types; one detecting a male sex pheromone and a second detecting 17β-estradiol 3-glucuronate, a putative female-derived signal. However, O. mossambicus differs markedly in its olfactory perception from the more recently derived East African cichlid

  12. Olfactory Perceptual Learning Requires Action of Noradrenaline in the Olfactory Bulb: Comparison with Olfactory Associative Learning

    ERIC Educational Resources Information Center

    Vinera, Jennifer; Kermen, Florence; Sacquet, Joëlle; Didier, Anne; Mandairon, Nathalie; Richard, Marion

    2015-01-01

    Noradrenaline contributes to olfactory-guided behaviors but its role in olfactory learning during adulthood is poorly documented. We investigated its implication in olfactory associative and perceptual learning using local infusion of mixed a1-ß adrenergic receptor antagonist (labetalol) in the adult mouse olfactory bulb. We reported that…

  13. Olfactory receptor responding to gut microbiota-derived signals plays a role in renin secretion and blood pressure regulation.

    PubMed

    Pluznick, Jennifer L; Protzko, Ryan J; Gevorgyan, Haykanush; Peterlin, Zita; Sipos, Arnold; Han, Jinah; Brunet, Isabelle; Wan, La-Xiang; Rey, Federico; Wang, Tong; Firestein, Stuart J; Yanagisawa, Masashi; Gordon, Jeffrey I; Eichmann, Anne; Peti-Peterdi, Janos; Caplan, Michael J

    2013-03-12

    Olfactory receptors are G protein-coupled receptors that mediate olfactory chemosensation and serve as chemosensors in other tissues. We find that Olfr78, an olfactory receptor expressed in the kidney, responds to short chain fatty acids (SCFAs). Olfr78 is expressed in the renal juxtaglomerular apparatus, where it mediates renin secretion in response to SCFAs. In addition, both Olfr78 and G protein-coupled receptor 41 (Gpr41), another SCFA receptor, are expressed in smooth muscle cells of small resistance vessels. Propionate, a SCFA shown to induce vasodilation ex vivo, produces an acute hypotensive response in wild-type mice. This effect is differentially modulated by disruption of Olfr78 and Gpr41 expression. SCFAs are end products of fermentation by the gut microbiota and are absorbed into the circulation. Antibiotic treatment reduces the biomass of the gut microbiota and elevates blood pressure in Olfr78 knockout mice. We conclude that SCFAs produced by the gut microbiota modulate blood pressure via Olfr78 and Gpr41. PMID:23401498

  14. Olfactory receptor responding to gut microbiota-derived signals plays a role in renin secretion and blood pressure regulation.

    PubMed

    Pluznick, Jennifer L; Protzko, Ryan J; Gevorgyan, Haykanush; Peterlin, Zita; Sipos, Arnold; Han, Jinah; Brunet, Isabelle; Wan, La-Xiang; Rey, Federico; Wang, Tong; Firestein, Stuart J; Yanagisawa, Masashi; Gordon, Jeffrey I; Eichmann, Anne; Peti-Peterdi, Janos; Caplan, Michael J

    2013-03-12

    Olfactory receptors are G protein-coupled receptors that mediate olfactory chemosensation and serve as chemosensors in other tissues. We find that Olfr78, an olfactory receptor expressed in the kidney, responds to short chain fatty acids (SCFAs). Olfr78 is expressed in the renal juxtaglomerular apparatus, where it mediates renin secretion in response to SCFAs. In addition, both Olfr78 and G protein-coupled receptor 41 (Gpr41), another SCFA receptor, are expressed in smooth muscle cells of small resistance vessels. Propionate, a SCFA shown to induce vasodilation ex vivo, produces an acute hypotensive response in wild-type mice. This effect is differentially modulated by disruption of Olfr78 and Gpr41 expression. SCFAs are end products of fermentation by the gut microbiota and are absorbed into the circulation. Antibiotic treatment reduces the biomass of the gut microbiota and elevates blood pressure in Olfr78 knockout mice. We conclude that SCFAs produced by the gut microbiota modulate blood pressure via Olfr78 and Gpr41.

  15. Structural determinants of odorant recognition by the human olfactory receptors OR1A1 and OR1A2.

    PubMed

    Schmiedeberg, Kristin; Shirokova, Elena; Weber, Hans-Peter; Schilling, Boris; Meyerhof, Wolfgang; Krautwurst, Dietmar

    2007-09-01

    An interaction of odorants with olfactory receptors is thought to be the initial step in odorant detection. However, ligands have been reported for only 6 out of 380 human olfactory receptors, with their structural determinants of odorant recognition just beginning to emerge. Guided by the notion that amino acid positions that interact with specific odorants would be conserved in orthologs, but variable in paralogs, and based on the prediction of a set of 22 of such amino acid positions, we have combined site-directed mutagenesis, rhodopsin-based homology modelling, and functional expression in HeLa/Olf cells of receptors OR1A1 and OR1A2. We found that (i) their odorant profiles are centred around citronellic terpenoid structures, (ii) two evolutionary conserved amino acid residues in transmembrane domain 3 are necessary for the responsiveness of OR1A1 and the mouse ortholog Olfr43 to (S)-(-)-citronellol, (iii) changes at these two positions are sufficient to account for the differential (S)-(-)-citronellol responsiveness of the paralogs OR1A1 and OR1A2, and (iv) the interaction sites for (S)-(-)-citronellal and (S)-(-)-citronellol differ in both human receptors. Our results show that the orientation of odorants within a homology modelling-derived binding pocket of olfactory receptor orthologs is defined by evolutionary conserved amino acid positions.

  16. Sex bias in copy number variation of olfactory receptor gene family depends on ethnicity.

    PubMed

    Shadravan, Farideh

    2013-01-01

    Gender plays a pivotal role in the human genetic identity and is also manifested in many genetic disorders particularly mental retardation. In this study its effect on copy number variation (CNV), known to cause genetic disorders was explored. As the olfactory receptor (OR) repertoire comprises the largest human gene family, it was selected for this study, which was carried out within and between three populations, derived from 150 individuals from the 1000 Genome Project. Analysis of 3872 CNVs detected among 791 OR loci, in which 307 loci showed CNV, revealed the following novel findings: Sex bias in CNV was significantly more prevalent in uncommon than common CNV variants of OR pseudogenes, in which the male genome showed more CNVs; and in one-copy number loss compared to complete deletion of OR pseudogenes; both findings implying a more recent evolutionary role for gender. Sex bias in copy number gain was also detected. Another novel finding was that the observed sex bias was largely dependent on ethnicity and was in general absent in East Asians. Using a CNV public database for sick children (International Standard Cytogenomic Array Consortium) the application of these findings for improving clinical molecular diagnostics is discussed by showing an example of sex bias in CNV among kids with autism. Additional clinical relevance is discussed, as the most polymorphic CNV-enriched OR cluster in the human genome, located on chr 15q11.2, is found near the Prader-Willi syndrome/Angelman syndrome bi-directionally imprinted region associated with two well-known mental retardation syndromes. As olfaction represents the primitive cognition in most mammals, arguably in competition with the development of a larger brain, the extensive retention of OR pseudogenes in females of this study, might point to a parent-of-origin indirect regulatory role for OR pseudogenes in the embryonic development of human brain. Thus any perturbation in the temporal regulation of olfactory

  17. Non-conventional therapeutics for oral infections.

    PubMed

    Allaker, Robert P; Ian Douglas, C W

    2015-01-01

    As our knowledge of host-microbial interactions within the oral cavity increases, future treatments are likely to be more targeted. For example, efforts to target a single species or key virulence factors that they produce, while maintaining the natural balance of the resident oral microbiota that acts to modulate the host immune response would be an advantage. Targeted approaches may be directed at the black-pigmented anaerobes, Porphyromonas gingivalis and Prevotella intermedia, associated with periodontitis. Such pigments provide an opportunity for targeted phototherapy with high-intensity monochromatic light. Functional inhibition approaches, including the use of enzyme inhibitors, are also being explored to control periodontitis. More general disruption of dental plaque through the use of enzymes and detergents, alone and in combination, shows much promise. The use of probiotics and prebiotics to improve gastrointestinal health has now led to an interest in using these approaches to control oral disease. More recently the potential of antimicrobial peptides and nanotechnology, through the application of nanoparticles with biocidal, anti-adhesive and delivery capabilities, has been explored. The aim of this review is to consider the current status as regards non-conventional treatment approaches for oral infections with particular emphasis on the plaque-related diseases. PMID:25668296

  18. Non-conventional therapeutics for oral infections

    PubMed Central

    Allaker, Robert P; Ian Douglas, CW

    2015-01-01

    As our knowledge of host-microbial interactions within the oral cavity increases, future treatments are likely to be more targeted. For example, efforts to target a single species or key virulence factors that they produce, while maintaining the natural balance of the resident oral microbiota that acts to modulate the host immune response would be an advantage. Targeted approaches may be directed at the black-pigmented anaerobes, Porphyromonas gingivalis and Prevotella intermedia, associated with periodontitis. Such pigments provide an opportunity for targeted phototherapy with high-intensity monochromatic light. Functional inhibition approaches, including the use of enzyme inhibitors, are also being explored to control periodontitis. More general disruption of dental plaque through the use of enzymes and detergents, alone and in combination, shows much promise. The use of probiotics and prebiotics to improve gastrointestinal health has now led to an interest in using these approaches to control oral disease. More recently the potential of antimicrobial peptides and nanotechnology, through the application of nanoparticles with biocidal, anti-adhesive and delivery capabilities, has been explored. The aim of this review is to consider the current status as regards non-conventional treatment approaches for oral infections with particular emphasis on the plaque-related diseases. PMID:25668296

  19. A gene recently inactivated in human defines a new olfactory receptor family in mammals.

    PubMed

    Rouquier, S; Friedman, C; Delettre, C; van den Engh, G; Blancher, A; Crouau-Roy, B; Trask, B J; Giorgi, D

    1998-09-01

    The olfactory receptor (OR) gene family constitutes one of the largest multigene families and is distributed among many chromosomal sites in the human genome. Four OR families have been defined in mammals. We previously demonstrated that a high fraction of human OR sequences have incurred deleterious mutations, thus reducing the repertoire of functional OR genes. In this study, we have characterized a new OR gene, 912-93, in primates. This gene is unique and it defines a new OR family. It localizes to human chromosome 11q11-12 and at syntenical sites in other hominoids. The sequence marks a previously unrecognized rearrangement of pericentromeric material from chromosome 11 to the centromeric region of gibbon chromosome 5. The human gene contains a nonsense point mutation in the region corresponding to the extracellular N-terminus of the receptor. This mutation is present in humans of various ethnic groups, but is absent in apes, suggesting that it probably appeared during the divergence of humans from other apes, <4 000 000-5 000 000 years ago. A second mutation, a frameshift at a different location, has occurred in the gorilla copy of this gene. These observations suggest that OR 912-93 has been recently silenced in human and gorilla, adding to a pool of OR pseudogenes whose growth may parallel a reduction in the sense of smell in primates.

  20. Identification and Knockdown of the Olfactory Receptor (OrCo) in Gypsy Moth, Lymantria dispar.

    PubMed

    Lin, Wei; Yu, Yanxue; Zhou, Ping; Zhang, Junhua; Dou, Liduo; Hao, Qin; Chen, Hongjun; Zhu, Shuifang

    2015-01-01

    The gypsy moth, Lymantria dispar, is an important economic pest that causes large-scale damage to forests worldwide. Because of its important role in initiating and controlling insect behavior, olfaction-and olfaction-based pest management-has drawn increasing attention from entomologists. In this study, we identified the gene that encodes the olfactory receptor co-receptor (OrCo). Through amino acid sequence alignment, we found that LdisOrCo shares high identity with other OrCo proteins from different insect orders. Next, we performed RNA-interference (RNAi) to assess the role of OrCo in olfaction. Electroantennographic assays showed that after RNAi, the average value of males' response to sex pheromones was 0.636 mV, significantly lower than that of the positive control (average = 1.472 mV). Females showed no response to sex pheromones before or after RNAi. Finally, quantitative PCR showed a strong decrease in the expression of OrCo after RNAi, by ~74% in males and by 23% in females relative to the positive controls. These results indicate that OrCo is not only critical to odor recognition, but it may also represent a new target for development of semiochemicals that can influence insect behavior. PMID:26078719

  1. Identification and Knockdown of the Olfactory Receptor (OrCo) in Gypsy Moth, Lymantria dispar.

    PubMed

    Lin, Wei; Yu, Yanxue; Zhou, Ping; Zhang, Junhua; Dou, Liduo; Hao, Qin; Chen, Hongjun; Zhu, Shuifang

    2015-01-01

    The gypsy moth, Lymantria dispar, is an important economic pest that causes large-scale damage to forests worldwide. Because of its important role in initiating and controlling insect behavior, olfaction-and olfaction-based pest management-has drawn increasing attention from entomologists. In this study, we identified the gene that encodes the olfactory receptor co-receptor (OrCo). Through amino acid sequence alignment, we found that LdisOrCo shares high identity with other OrCo proteins from different insect orders. Next, we performed RNA-interference (RNAi) to assess the role of OrCo in olfaction. Electroantennographic assays showed that after RNAi, the average value of males' response to sex pheromones was 0.636 mV, significantly lower than that of the positive control (average = 1.472 mV). Females showed no response to sex pheromones before or after RNAi. Finally, quantitative PCR showed a strong decrease in the expression of OrCo after RNAi, by ~74% in males and by 23% in females relative to the positive controls. These results indicate that OrCo is not only critical to odor recognition, but it may also represent a new target for development of semiochemicals that can influence insect behavior.

  2. Ligand-selective activation of heterologously-expressed mammalian olfactory receptor.

    PubMed

    Ukhanov, K; Bobkov, Y; Corey, E A; Ache, B W

    2014-10-01

    Mammalian olfactory receptors (ORs) appear to have the capacity to couple to multiple G protein-coupled signaling pathways in a ligand-dependent selective manner. To better understand the mechanisms and molecular range of such ligand selectivity, we expressed the mouse eugenol OR (mOR-EG) in HEK293T cells together with Gα15 to monitor activation of the phospholipase-C (PLC) signaling pathway and/or Gαolf to monitor activation of the adenylate cyclase (AC) signaling pathway, resulting in intracellular Ca(2+) release and/or Ca(2+) influx through a cyclic nucleotide-gated channel, respectively. PLC-dependent responses differed dynamically from AC-dependent responses, allowing them to be distinguished when Gα15 and Gαolf were co-expressed. The dynamic difference in readout was independent of the receptor, the heterologous expression system, and the ligand concentration. Of 17 reported mOR-EG ligands tested, including eugenol, its analogs, and structurally dissimilar compounds (mousse cristal, nootkatone, orivone), some equally activated both signaling pathways, some differentially activated both signaling pathways, and some had no noticeable effect even at 1-5mM. Our findings argue that mOR-EG, when heterologously expressed, can couple to two different signaling pathways in a ligand selective manner. The challenge now is to determine the potential of mOR-EG, and perhaps other ORs, to activate multiple signaling pathways in a ligand selective manner in native ORNs. PMID:25149566

  3. Ligand-selective activation of heterologously-expressed mammalian olfactory receptor

    PubMed Central

    Ukhanov, K.; Bobkov, Y.; Corey, E.A.; Ache, B.W.

    2014-01-01

    Mammalian olfactory receptors (ORs) appear to have the capacity to couple to multiple G protein-coupled signaling pathways in a ligand-dependent selective manner. To better understand the mechanisms and molecular range of such ligand selectivity, we expressed the mouse eugenol OR (mOR-EG) in HEK293T cells together with Gα15 to monitor activation of the phospholipase-C (PLC) signaling pathway and/or Gαolf to monitor activation of the adenylate cyclase (AC) signaling pathway, resulting in intracellular Ca2+ release and/or Ca2+ influx through a cyclic nucleotide-gated channel, respectively. PLC-dependent responses differed dynamically from AC-dependent responses, allowing them to be distinguished when Gα15 and Gαolf were co-expressed. The dynamic difference in readout was independent of the receptor, the heterologous expression system, and the ligand concentration. Of 17 reported mOR-EG ligands tested, including eugenol, its analogs, and structurally dissimilar compounds (mousse cristal, nootkatone, orivone), some equally activated both signaling pathways, some differentially activated both signaling pathways, and some had no noticeable effect even at 1-5 mM. Our findings argue that mOR-EG, when heterologously expressed, can couple to two different signaling pathways in a ligand selective manner. The challenge now is to determine the potential of mOR-EG, and perhaps other ORs, to activate multiple signaling pathways in a ligand selective manner in native ORNs. PMID:25149566

  4. Presynaptic GABA Receptors Mediate Temporal Contrast Enhancement in Drosophila Olfactory Sensory Neurons and Modulate Odor-Driven Behavioral Kinetics

    PubMed Central

    Demir, Mahmut; Gorur-Shandilya, Srinivas; Kunst, Michael; Nitabach, Michael N.

    2016-01-01

    Contrast enhancement mediated by lateral inhibition within the nervous system enhances the detection of salient features of visual and auditory stimuli, such as spatial and temporal edges. However, it remains unclear how mechanisms for temporal contrast enhancement in the olfactory system can enhance the detection of odor plume edges during navigation. To address this question, we delivered to Drosophila melanogaster flies pulses of high odor intensity that induce sustained peripheral responses in olfactory sensory neurons (OSNs). We use optical electrophysiology to directly measure electrical responses in presynaptic terminals and demonstrate that sustained peripheral responses are temporally sharpened by the combined activity of two types of inhibitory GABA receptors to generate contrast-enhanced voltage responses in central OSN axon terminals. Furthermore, we show how these GABA receptors modulate the time course of innate behavioral responses after odor pulse termination, demonstrating an important role for temporal contrast enhancement in odor-guided navigation. PMID:27588305

  5. Presynaptic GABA Receptors Mediate Temporal Contrast Enhancement in Drosophila Olfactory Sensory Neurons and Modulate Odor-Driven Behavioral Kinetics.

    PubMed

    Raccuglia, Davide; Yan McCurdy, Li; Demir, Mahmut; Gorur-Shandilya, Srinivas; Kunst, Michael; Emonet, Thierry; Nitabach, Michael N

    2016-01-01

    Contrast enhancement mediated by lateral inhibition within the nervous system enhances the detection of salient features of visual and auditory stimuli, such as spatial and temporal edges. However, it remains unclear how mechanisms for temporal contrast enhancement in the olfactory system can enhance the detection of odor plume edges during navigation. To address this question, we delivered to Drosophila melanogaster flies pulses of high odor intensity that induce sustained peripheral responses in olfactory sensory neurons (OSNs). We use optical electrophysiology to directly measure electrical responses in presynaptic terminals and demonstrate that sustained peripheral responses are temporally sharpened by the combined activity of two types of inhibitory GABA receptors to generate contrast-enhanced voltage responses in central OSN axon terminals. Furthermore, we show how these GABA receptors modulate the time course of innate behavioral responses after odor pulse termination, demonstrating an important role for temporal contrast enhancement in odor-guided navigation. PMID:27588305

  6. Integrated Approaches for Genome-wide Interrogation of the Druggable Non-olfactory G Protein-coupled Receptor Superfamily*

    PubMed Central

    Roth, Bryan L.; Kroeze, Wesley K.

    2015-01-01

    G-protein-coupled receptors (GPCRs) are frequent and fruitful targets for drug discovery and development, as well as being off-targets for the side effects of a variety of medications. Much of the druggable non-olfactory human GPCR-ome remains under-interrogated, and we present here various approaches that we and others have used to shine light into these previously dark corners of the human genome. PMID:26100629

  7. Insights into the olfactory system of the ectoparasite Caligus rogercresseyi: molecular characterization and gene transcription analysis of novel ionotropic receptors.

    PubMed

    Núñez-Acuña, Gustavo; Valenzuela-Muñoz, Valentina; Marambio, Jorge Pino; Wadsworth, Simon; Gallardo-Escárate, Cristian

    2014-10-01

    Although various elements of the olfactory system have been elucidated in insects, it remains practically unstudied in crustaceans at a molecular level. Among crustaceans, some species are classified as ectoparasites that impact the finfish aquaculture industry. Thus, there is an urgent need to identify and comprehend the signaling pathways used by these in host recognition. The present study, through RNA-seq and qPCR analyses, found novel transcripts involved in the olfactory system of Caligus rogercresseyi, in addition to the transcriptomic patterns expressed during different stages of salmon lice development. From a transcriptomic library generated by Illumina sequencing, contigs that annotated for ionotropic receptors and other genes implicated in the olfactory system were identified and extracted. Full length mRNA was obtained for the ionotropic glutamate receptor 25, which had 3923 bp, and for the glutamate receptor ionotropic kainate 2, which had 2737 bp. Furthermore, two other transcripts identified as glutamate receptor, ionotropic kainate 2-like were found. In silico analysis was performed for the transcription expression from different stages of development in C. rogercresseyi, and clusters according to RPKM values were constructed. Gene transcription data were validated through qPCR assays in ionotropic receptors, and showed an expression of glutamate receptor 25 associated with the copepodid stage whereas adults, especially male adults, were associated with the kainate 2 and kainate 2-like transcripts. Additionally, gene transcription analysis of the ionotropic receptors showed an overexpression in response to the presence of masking compounds and immunostimulant in salmon diets. This response correlated to a reduction in sea lice infection following in vivo challenge. Diets with masking compounds showed a decrease of lice infestation of up to 25%. This work contributes to the available knowledge on chemosensory systems in this ectoparasite, providing

  8. Toll receptors instruct axon and dendrite targeting and participate in synaptic partner matching in a Drosophila olfactory circuit.

    PubMed

    Ward, Alex; Hong, Weizhe; Favaloro, Vincenzo; Luo, Liqun

    2015-03-01

    Our understanding of the mechanisms that establish wiring specificity of complex neural circuits is far from complete. During Drosophila olfactory circuit assembly, axons of 50 olfactory receptor neuron (ORN) classes and dendrites of 50 projection neuron (PN) classes precisely target to 50 discrete glomeruli, forming parallel information-processing pathways. Here we show that Toll-6 and Toll-7, members of the Toll receptor family best known for functions in innate immunity and embryonic patterning, cell autonomously instruct the targeting of specific classes of PN dendrites and ORN axons, respectively. The canonical ligands and downstream partners of Toll receptors in embryonic patterning and innate immunity are not required for the function of Toll-6/Toll-7 in wiring specificity, nor are their cytoplasmic domains. Interestingly, both Toll-6 and Toll-7 participate in synaptic partner matching between ORN axons and PN dendrites. Our investigations reveal that olfactory circuit assembly involves dynamic and long-range interactions between PN dendrites and ORN axons.

  9. Pre- and Postsynaptic Role of Dopamine D2 Receptor DD2R in Drosophila Olfactory Associative Learning.

    PubMed

    Qi, Cheng; Lee, Daewoo

    2014-01-01

    Dopaminergic neurons in Drosophila play critical roles in diverse brain functions such as motor control, arousal, learning, and memory. Using genetic and behavioral approaches, it has been firmly established that proper dopamine signaling is required for olfactory classical conditioning (e.g., aversive and appetitive learning). Dopamine mediates its functions through interaction with its receptors. There are two different types of dopamine receptors in Drosophila: D1-like (dDA1, DAMB) and D2-like receptors (DD2R). Currently, no study has attempted to characterize the role of DD2R in Drosophila learning and memory. Using a DD2R-RNAi transgenic line, we have examined the role of DD2R, expressed in dopamine neurons (i.e., the presynaptic DD2R autoreceptor), in larval olfactory learning. The function of postsynaptic DD2R expressed in mushroom body (MB) was also studied as MB is the center for Drosophila learning, with a function analogous to that of the mammalian hippocampus. Our results showed that suppression of presynaptic DD2R autoreceptors impairs both appetitive and aversive learning. Similarly, postsynaptic DD2R in MB neurons appears to be involved in both appetitive and aversive learning. The data confirm, for the first time, that DD2R plays an important role in Drosophila olfactory learning. PMID:25422852

  10. Pre- and Postsynaptic Role of Dopamine D2 Receptor DD2R in Drosophila Olfactory Associative Learning

    PubMed Central

    Qi, Cheng; Lee, Daewoo

    2014-01-01

    Dopaminergic neurons in Drosophila play critical roles in diverse brain functions such as motor control, arousal, learning, and memory. Using genetic and behavioral approaches, it has been firmly established that proper dopamine signaling is required for olfactory classical conditioning (e.g., aversive and appetitive learning). Dopamine mediates its functions through interaction with its receptors. There are two different types of dopamine receptors in Drosophila: D1-like (dDA1, DAMB) and D2-like receptors (DD2R). Currently, no study has attempted to characterize the role of DD2R in Drosophila learning and memory. Using a DD2R-RNAi transgenic line, we have examined the role of DD2R, expressed in dopamine neurons (i.e., the presynaptic DD2R autoreceptor), in larval olfactory learning. The function of postsynaptic DD2R expressed in mushroom body (MB) was also studied as MB is the center for Drosophila learning, with a function analogous to that of the mammalian hippocampus. Our results showed that suppression of presynaptic DD2R autoreceptors impairs both appetitive and aversive learning. Similarly, postsynaptic DD2R in MB neurons appears to be involved in both appetitive and aversive learning. The data confirm, for the first time, that DD2R plays an important role in Drosophila olfactory learning. PMID:25422852

  11. An olfactory receptor for food-derived odours promotes male courtship in Drosophila.

    PubMed

    Grosjean, Yael; Rytz, Raphael; Farine, Jean-Pierre; Abuin, Liliane; Cortot, Jérôme; Jefferis, Gregory S X E; Benton, Richard

    2011-10-13

    Many animals attract mating partners through the release of volatile sex pheromones, which can convey information on the species, gender and receptivity of the sender to induce innate courtship and mating behaviours by the receiver. Male Drosophila melanogaster fruitflies display stereotyped reproductive behaviours towards females, and these behaviours are controlled by the neural circuitry expressing male-specific isoforms of the transcription factor Fruitless (FRU(M)). However, the volatile pheromone ligands, receptors and olfactory sensory neurons (OSNs) that promote male courtship have not been identified in this important model organism. Here we describe a novel courtship function of Ionotropic receptor 84a (IR84a), which is a member of the chemosensory ionotropic glutamate receptor family, in a previously uncharacterized population of FRU(M)-positive OSNs. IR84a-expressing neurons are activated not by fly-derived chemicals but by the aromatic odours phenylacetic acid and phenylacetaldehyde, which are widely found in fruit and other plant tissues that serve as food sources and oviposition sites for drosophilid flies. Mutation of Ir84a abolishes both odour-evoked and spontaneous electrophysiological activity in these neurons and markedly reduces male courtship behaviour. Conversely, male courtship is increased--in an IR84a-dependent manner--in the presence of phenylacetic acid but not in the presence of another fruit odour that does not activate IR84a. Interneurons downstream of IR84a-expressing OSNs innervate a pheromone-processing centre in the brain. Whereas IR84a orthologues and phenylacetic-acid-responsive neurons are present in diverse drosophilid species, IR84a is absent from insects that rely on long-range sex pheromones. Our results suggest a model in which IR84a couples food presence to the activation of the fru(M) courtship circuitry in fruitflies. These findings reveal an unusual but effective evolutionary solution to coordinate feeding and

  12. Intensity invariant dynamics and odor-specific latencies in olfactory receptor neuron response

    PubMed Central

    Martelli, Carlotta; Carlson, John R.; Emonet, Thierry

    2013-01-01

    Odors elicit spatio-temporal patterns of activity in the brain. Spatial patterns arise from the specificity of the interaction between odorants and odorant receptors expressed in different olfactory receptor neurons (ORNs). But the origin of temporal patterns of activity and their role in odor coding remain unclear. We investigate how physiological aspects of ORN response and physical aspects of odor stimuli give rise to diverse responses in Drosophila ORNs. We show that odor stimuli have intrinsic dynamics that depend on odor type and strongly affect ORN response. Using linear-nonlinear modeling to remove the contribution of the stimulus dynamics from the ORN dynamics we study the physiological properties of the response to different odorants and concentrations. For several odorants and receptor types the ORN response dynamics normalized by the peak response are independent of stimulus intensity for a large portion of the neuron’s dynamic range. Adaptation to a background odor changes the gain and dynamic range of the response but does not affect normalized response dynamics. Stimulating ORNs with various odorants reveals significant odor-dependent delays in the ORN response functions. These differences however can be dominated by differences in stimulus dynamics. In one case the response of one ORN to two odorants is predicted solely from measurements of the odor signals. Within a large portion of their dynamic range ORNs can capture information about stimulus dynamics independently from intensity while introducing odor-dependent delays. How insects might use odor-specific stimulus dynamics and ORN dynamics in discrimination and navigation tasks remains an open question. PMID:23575828

  13. A novel method to study insect olfactory receptor function using HEK293 cells.

    PubMed

    Corcoran, Jacob A; Jordan, Melissa D; Carraher, Colm; Newcomb, Richard D

    2014-11-01

    The development of rapid and reliable assays to characterize insect odorant receptors (ORs) and pheromone receptors (PRs) remains a challenge for the field. Typically ORs and PRs are functionally characterized either in vivo in transgenic Drosophila or in vitro through expression in Xenopus oocytes. While these approaches have succeeded, they are not well suited for high-throughput screening campaigns, primarily due to inherent characteristics that limit their ability to screen large quantities of compounds in a short period of time. The development of a practical, robust and consistent in vitro assay for functional studies on ORs and PRs would allow for high-throughput screening for ligands, as well as for compounds that could be used as novel olfactory-based pest management tools. Here we describe a novel method of utilizing human embryonic kidney cells (HEK293) transfected with inducible receptor constructs for the functional characterization of ORs in 96-well plates using a fluorescent spectrophotometer. Using EposOrco and EposOR3 from the pest moth, Epiphyas postvittana as an example, we generated HEK293 cell lines with robust and consistent responses to ligands in functional assays. Single-cell sorting of cell lines by FACS facilitated the selection of isogenic cell lines with maximal responses, and the addition of epitope tags on the N-termini allowed the detection of recombinant proteins in homogenates by western blot and in cells by immunocytochemistry. We thoroughly describe the methods used to generate these OR-expressing cell lines, demonstrating that they have all the necessary features required for use in high-throughput screening platforms.

  14. Differential expression of olfactory genes in the southern house mosquito and insights into unique odorant receptor gene isoforms

    PubMed Central

    Leal, Walter S.; Choo, Young-Moo; Xu, Pingxi; da Silva, Cherre S. B.; Ueira-Vieira, Carlos

    2013-01-01

    The southern house mosquito, Culex quinquefasciatus, has one of the most acute and eclectic olfactory systems of all mosquito species hitherto studied. Here, we used Illumina sequencing to identify olfactory genes expressed predominantly in antenna, mosquito’s main olfactory organ. Less than 50% of the trimmed reads generated by high-quality libraries aligned to a transcript, but approximately 70% of them aligned to the genome. Differential expression analysis, which was validated by quantitative real-time PCR on a subset of genes, showed that approximately half of the 48 odorant-binding protein genes were enriched in antennae, with the other half being predominantly expressed in legs. Similar patterns were observed with chemosensory proteins, “plus-C” odorant-binding proteins, and sensory neuron membrane proteins. Transcripts for as many as 43 ionotropic receptors were enriched in female antennae, thus making the ionotropic receptor family the largest of antennae-rich olfactory genes, second only to odorant receptor (OR) genes. As many as 177 OR genes have been identified, including 36 unique transcripts. The unique OR genes differed from previously annotated ORs in internal sequences, splice variants, and extended N or C terminus. One of the previously unknown transcripts was validated by cloning and functional expression. When challenged with a large panel of physiologically relevant compounds, CquiOR95b responded in a dose-dependent manner to ethyl 2-phenylacteate, which was demonstrated to repel Culex mosquitoes, and secondarily to citronellal, a known insect repellent. This transcriptome study led to identification of key molecular components and a repellent for the southern house mosquito. PMID:24167245

  15. Differential expression of olfactory genes in the southern house mosquito and insights into unique odorant receptor gene isoforms.

    PubMed

    Leal, Walter S; Choo, Young-Moo; Xu, Pingxi; da Silva, Cherre S B; Ueira-Vieira, Carlos

    2013-11-12

    The southern house mosquito, Culex quinquefasciatus, has one of the most acute and eclectic olfactory systems of all mosquito species hitherto studied. Here, we used Illumina sequencing to identify olfactory genes expressed predominantly in antenna, mosquito's main olfactory organ. Less than 50% of the trimmed reads generated by high-quality libraries aligned to a transcript, but approximately 70% of them aligned to the genome. Differential expression analysis, which was validated by quantitative real-time PCR on a subset of genes, showed that approximately half of the 48 odorant-binding protein genes were enriched in antennae, with the other half being predominantly expressed in legs. Similar patterns were observed with chemosensory proteins, "plus-C" odorant-binding proteins, and sensory neuron membrane proteins. Transcripts for as many as 43 ionotropic receptors were enriched in female antennae, thus making the ionotropic receptor family the largest of antennae-rich olfactory genes, second only to odorant receptor (OR) genes. As many as 177 OR genes have been identified, including 36 unique transcripts. The unique OR genes differed from previously annotated ORs in internal sequences, splice variants, and extended N or C terminus. One of the previously unknown transcripts was validated by cloning and functional expression. When challenged with a large panel of physiologically relevant compounds, CquiOR95b responded in a dose-dependent manner to ethyl 2-phenylacteate, which was demonstrated to repel Culex mosquitoes, and secondarily to citronellal, a known insect repellent. This transcriptome study led to identification of key molecular components and a repellent for the southern house mosquito.

  16. Functional characterization of the ectopically expressed olfactory receptor 2AT4 in human myelogenous leukemia.

    PubMed

    Manteniotis, S; Wojcik, S; Brauhoff, P; Möllmann, M; Petersen, L; Göthert, J R; Schmiegel, W; Dührsen, U; Gisselmann, G; Hatt, H

    2016-01-01

    The olfactory receptor (OR) family was found to be expressed mainly in the nasal epithelium. In the last two decades members of the OR family were detected to be functional expressed in different parts of the human body such as in liver, prostate or intestine cancer cells. Here, we detected the expression of several ORs in the human chronic myelogenous leukemia (CML) cell line K562 and in white blood cells of clinically diagnosed acute myeloid leukemia (AML) patients by RT-PCR and next-generation sequencing. With calcium-imaging, we characterized in greater detail the cell biological role of one OR (OR2AT4) in leukemia. In both cell systems, the OR2AT4 agonist Sandalore-evoked strong Ca(2+) influx via the adenylate cyclase-cAMP-mediated pathway. The OR2AT4 antagonist Phenirat prevented the Sandalore-induced intracellular Ca(2+) increase. Western blot and flow cytometric experiments revealed that stimulation of OR2AT4 reduced the proliferation by decreasing p38-MAPK phosphorylation and induced apoptosis via phosphorylation of p44/42-MAPK. Furthermore, Sandalore increased the number of hemoglobin-containing cells in culture. We described for the first time an OR-mediated pathway in CML and AML that can regulate proliferation, apoptosis and differentiation after activation. This mechanism offers novel therapeutic options for the treatment of AML. PMID:27551494

  17. Effect of non-selective dopaminergic receptor agonist on disrupted maternal behavior in olfactory bulbectomized mice.

    PubMed

    Sato, Atsushi; Nakagawasai, Osamu; Tan-No, Koichi; Onogi, Hiroshi; Niijima, Fukie; Tadano, Takeshi

    2010-07-11

    Olfactory bulbectomy (OBX) animals are considered a putative model of depression that produces behavioral, physiological, and neurochemical alterations resembling clinical depression. Depression is a critical cause of child abuse and neglect, and it has been reported that maternal behavior involves dopaminergic neurons of the mesolimbic pathway. In this study, we investigated the effect of apomorphine, a non-selective dopaminergic receptor agonist, on maternal behavior to examine the influence of activated brain dopaminergic function in OBX mice. In addition, we conducted the sucrose preference test to examine the reward system which has a critical relationship to mesolimbic dopaminergic function and maternal behavior. Maternal behavior was observed on postnatal day (PND) 0 and 4. OBX female mice showed a reduction in sucrose preference 2 weeks post surgery. OBX dams showed maternal behavior deficits on PND 0, and these deficits were ameliorated by administration of apomorphine. These results suggest that maternal behavior deficits in OBX dams may involve brain hypodopaminergic function in the central nervous system induced by OBX. PMID:20219556

  18. Oxygen control of breathing by an olfactory receptor activated by lactate

    PubMed Central

    Chang, Andy J.; Ortega, Fabian E.; Riegler, Johannes; Madison, Daniel V.; Krasnow, Mark A.

    2015-01-01

    Summary Animals have evolved homeostatic responses to changes in oxygen availability that act on different time scales. Although the hypoxia-inducible factor (HIF) transcriptional pathway that controls long term responses to low oxygen (hypoxia) has been established1, the pathway that mediates acute responses to hypoxia in mammals is not well understood. Here we show that the olfactory receptor Olfr78 is highly and selectively expressed in oxygen-sensitive glomus cells of the carotid body, a chemosensory organ at the carotid artery bifurcation that monitors blood oxygen and stimulates breathing within seconds when oxygen declines2. Olfr78 mutants fail to increase ventilation in hypoxia but respond normally to hypercapnia. Glomus cells are present in normal numbers and appear structurally intact, but hypoxia-induced carotid body activity is diminished. Lactate, a metabolite that rapidly accumulates in hypoxia and induces hyperventilation3–6, activates Olfr78 in heterologous expression experiments, induces calcium transients in glomus cells, and stimulates carotid sinus nerve activity through Olfr78. We propose that in addition to its role in olfaction, Olfr78 acts as a hypoxia sensor in the breathing circuit by sensing lactate produced when oxygen levels decline. PMID:26560302

  19. Olfactory Receptors Modulate Physiological Processes in Human Airway Smooth Muscle Cells

    PubMed Central

    Kalbe, Benjamin; Knobloch, Jürgen; Schulz, Viola M.; Wecker, Christine; Schlimm, Marian; Scholz, Paul; Jansen, Fabian; Stoelben, Erich; Philippou, Stathis; Hecker, Erich; Lübbert, Hermann; Koch, Andrea; Hatt, Hanns; Osterloh, Sabrina

    2016-01-01

    Pathophysiological mechanisms in human airway smooth muscle cells (HASMCs) significantly contribute to the progression of chronic inflammatory airway diseases with limited therapeutic options, such as severe asthma and COPD. These abnormalities include the contractility and hyperproduction of inflammatory proteins. To develop therapeutic strategies, key pathological mechanisms, and putative clinical targets need to be identified. In the present study, we demonstrated that the human olfactory receptors (ORs) OR1D2 and OR2AG1 are expressed at the RNA and protein levels in HASMCs. Using fluorometric calcium imaging, specific agonists for OR2AG1 and OR1D2 were identified to trigger transient Ca2+ increases in HASMCs via a cAMP-dependent signal transduction cascade. Furthermore, the activation of OR2AG1 via amyl butyrate inhibited the histamine-induced contraction of HASMCs, whereas the stimulation of OR1D2 with bourgeonal led to an increase in cell contractility. In addition, OR1D2 activation induced the secretion of IL-8 and GM-CSF. Both effects were inhibited by the specific OR1D2 antagonist undecanal. We herein provide the first evidence to show that ORs are functionally expressed in HASMCs and regulate pathophysiological processes. Therefore, ORs might be new therapeutic targets for these diseases, and blocking ORs could be an auspicious strategy for the treatment of early-stage chronic inflammatory lung diseases. PMID:27540365

  20. Orexin receptor activity in the basal forebrain alters performance on an olfactory discrimination task.

    PubMed

    Piantadosi, Patrick T; Holmes, Ashley; Roberts, Bradley M; Bailey, Aileen M

    2015-01-12

    Cholinergic innervation of the prefrontal cortex is critical for various forms of cognition, although the efferent modulators contributing to acetylcholine (ACh) release are not well understood. The main source of cortical ACh, the basal forebrain, receives projections from lateral and perifornical hypothalamic neurons releasing the peptides orexin (orexin A; OxA, and orexin B; OxB), of which OxA is hypothesized to play a role in various cognitive functions. We sought to assess one such function known to be susceptible to basal forebrain cholinergic manipulation, olfactory discrimination acquisition, and reversal learning, in rats following intra-basal forebrain infusion of OxA or the orexin 1 receptor (OxR1) antagonist SB-334867. OxA administration facilitated, while OxR1 antagonism impaired performance on both the acquisition and reversal portions of the task. These data suggest that orexin acting in the basal forebrain may be important for cortical-dependant executive functions, possibly through the stimulation of cortical ACh release.

  1. Functional characterization of the ectopically expressed olfactory receptor 2AT4 in human myelogenous leukemia

    PubMed Central

    Manteniotis, S; Wojcik, S; Brauhoff, P; Möllmann, M; Petersen, L; Göthert, JR; Schmiegel, W; Dührsen, U; Gisselmann, G; Hatt, H

    2016-01-01

    The olfactory receptor (OR) family was found to be expressed mainly in the nasal epithelium. In the last two decades members of the OR family were detected to be functional expressed in different parts of the human body such as in liver, prostate or intestine cancer cells. Here, we detected the expression of several ORs in the human chronic myelogenous leukemia (CML) cell line K562 and in white blood cells of clinically diagnosed acute myeloid leukemia (AML) patients by RT-PCR and next-generation sequencing. With calcium-imaging, we characterized in greater detail the cell biological role of one OR (OR2AT4) in leukemia. In both cell systems, the OR2AT4 agonist Sandalore-evoked strong Ca2+ influx via the adenylate cyclase-cAMP-mediated pathway. The OR2AT4 antagonist Phenirat prevented the Sandalore-induced intracellular Ca2+ increase. Western blot and flow cytometric experiments revealed that stimulation of OR2AT4 reduced the proliferation by decreasing p38-MAPK phosphorylation and induced apoptosis via phosphorylation of p44/42-MAPK. Furthermore, Sandalore increased the number of hemoglobin-containing cells in culture. We described for the first time an OR-mediated pathway in CML and AML that can regulate proliferation, apoptosis and differentiation after activation. This mechanism offers novel therapeutic options for the treatment of AML. PMID:27551494

  2. Phosphatidylinositol 4,5-bisphosphate-dependent regulation of the output in lobster olfactory receptor neurons.

    PubMed

    Bobkov, Yuriy V; Pezier, Adeline; Corey, Elizabeth A; Ache, Barry W

    2010-05-01

    Transient receptor potential (TRP) channels often play a role in sensory transduction, including chemosensory transduction. TRP channels, a common downstream target of phosphoinositide (PI) signaling, can be modulated by exogenous phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] and/or diacylglycerol (DAG). Lobster olfactory receptor neurons (ORNs) express a TRP-related, non-selective, calcium/magnesium-permeable, sodium/calcium-gated cation (SGC) channel. Here we report that PIs regulate the function of the calcium-activated form of the lobster channel. Sequestering of endogenous PI(4,5)P2, either with an anti-PI(4,5)P2 antibody or by electrostatic screening with polyvalent cations, blocks the channel. Exogenous PI(3,4,5)P3 activates the channel independently of intracellular sodium and/or calcium. Exogenous non-hydrolysable DAG analogs fail to change the gating parameters of the channel, suggesting the channel is insensitive to DAG. Electrophysiological recording from lobster ORNs in situ using a panel of pharmacological tools targeting the key components of both PI and DAG metabolism (phospholipase C, phosphoinositide 4-kinase and DAG kinase) extend these findings to the intact ORN. PI(4,5)P2 depletion suppresses both the odorant-evoked discharge and whole-cell current of the cells, and does so possibly independently of DAG production. Collectively, our results argue that PIs can regulate output in lobster ORNs, at least in part through their action on the lobster SGC channel.

  3. Regulation of cyclic nucleotide-gated channels and membrane excitability in olfactory receptor cells by carbon monoxide

    NASA Technical Reports Server (NTRS)

    Leinders-Zufall, T.; Shepherd, G. M.; Zufall, F.

    1995-01-01

    1. The effect of the putative neural messenger carbon monoxide (CO) and the role of the cGMP second-messenger system for olfactory signal generation was examined in isolated olfactory receptor neurons (ORNs) of the tiger salamander. 2. With the use of whole cell voltage-clamp recordings in combination with a series of ionic and pharmological tests, it is demonstrated that exogenously applied CO is a potent activator (K1/2 = 2.9 microM) of cyclic nucleotide-gated (CNG) channels previously described to mediate odor transduction. 3. Several lines of evidence suggest that CO mediates its effect through stimulation of a soluble guanylyl cyclase (sGC) leading to formation of the second-messenger cGMP. This conclusion is based on the findings that CO responses show an absolute requirement for guanosine 5'-triphosphate (GTP) in the internal solution, that no direct effect of CO on CNG currents in the absence of GTP is detectable, and that a blocker of sGC activation, LY85383 (10 microM), completely inhibits the CO response. 4. The dose-response curve for cGMP at CNG channels is used as a calibration to provide a quantitative estimate of the CO-stimulated cGMP formation. This analysis implies that CO is a potent activator of olfactory sGC. 5. Perforated patch recordings using amphotericin B demonstrate that low micromolar doses of CO effectively depolarize the membrane potential of ORNs through tonic activation of CNG channels. This effect in turn regulates excitable and adaptive properties of ORNs and modulates neuronal responsiveness. 6. These data argue for an important role of the cGMP pathway in olfactory signaling and support the idea that CO may function as a diffusible messenger in the olfactory system.

  4. Phenylthiophenecarboxamide antagonists of the olfactory receptor co-receptor subunit from a mosquito.

    PubMed

    Chen, Sisi; Luetje, Charles W

    2013-01-01

    Insects detect environmental chemicals using chemosensory receptors, such as the ORs, a family of odorant-gated ion channels. Insect ORs are multimeric complexes of unknown stoichiometry, formed by a common subunit (the odorant receptor co-receptor subunit, Orco) and one of many variable subunits that confer odorant specificity. The recent discovery of Orco directed ligands, including both agonists and antagonists, suggests Orco as a promising target for chemical control of insects. In addition to competitively inhibiting OR activation by Orco agonists, several Orco antagonists have been shown to act through a non-competitive mechanism to inhibit OR activation by odorants. We previously identified a series of Orco antagonists, including N-(4-ethylphenyl)-2-thiophenecarboxamide (OX1a, previously referred to as OLC20). Here, we explore the chemical space around the OX1a structure to identify more potent Orco antagonists. Cqui\\Orco+Cqui\\Or21, an OR from Culex quinquefasciatus (the Southern House Mosquito) that responds to 3-methylindole (skatole) and is thought to mediate oviposition behavior, was expressed in Xenopus oocytes and receptor function assayed by two-electrode voltage clamp electrophysiology. 22 structural analogs of OX1a were screened for antagonism of OR activation by an Orco agonist. By varying the moieties decorating the phenyl and thiophene rings, and altering the distance between the rings, we were able to identify antagonists with improved potency. Detailed examination of three of these compounds (N-mesityl-2-thiophenecarboxamide, N-(4-methylbenzyl)-2-thiophenecarboxamide and N-(2-ethylphenyl)-3-(2-thienyl)-2-propenamide) demonstrated competitive inhibition of receptor activation by an Orco agonist and non-competitive inhibition of receptor activation by an odorant. The ability to inhibit OR activation by odorants may be a general property of this class of Orco antagonist, suggesting that odorant mediated behaviors can be manipulated through Orco

  5. Phenylthiophenecarboxamide Antagonists of the Olfactory Receptor Co-Receptor Subunit from a Mosquito

    PubMed Central

    Chen, Sisi; Luetje, Charles W.

    2013-01-01

    Insects detect environmental chemicals using chemosensory receptors, such as the ORs, a family of odorant-gated ion channels. Insect ORs are multimeric complexes of unknown stoichiometry, formed by a common subunit (the odorant receptor co-receptor subunit, Orco) and one of many variable subunits that confer odorant specificity. The recent discovery of Orco directed ligands, including both agonists and antagonists, suggests Orco as a promising target for chemical control of insects. In addition to competitively inhibiting OR activation by Orco agonists, several Orco antagonists have been shown to act through a non-competitive mechanism to inhibit OR activation by odorants. We previously identified a series of Orco antagonists, including N-(4-ethylphenyl)-2-thiophenecarboxamide (OX1a, previously referred to as OLC20). Here, we explore the chemical space around the OX1a structure to identify more potent Orco antagonists. Cqui\\Orco+Cqui\\Or21, an OR from Culex quinquefasciatus (the Southern House Mosquito) that responds to 3-methylindole (skatole) and is thought to mediate oviposition behavior, was expressed in Xenopus oocytes and receptor function assayed by two-electrode voltage clamp electrophysiology. 22 structural analogs of OX1a were screened for antagonism of OR activation by an Orco agonist. By varying the moieties decorating the phenyl and thiophene rings, and altering the distance between the rings, we were able to identify antagonists with improved potency. Detailed examination of three of these compounds (N-mesityl-2-thiophenecarboxamide, N-(4-methylbenzyl)-2-thiophenecarboxamide and N-(2-ethylphenyl)-3-(2-thienyl)-2-propenamide) demonstrated competitive inhibition of receptor activation by an Orco agonist and non-competitive inhibition of receptor activation by an odorant. The ability to inhibit OR activation by odorants may be a general property of this class of Orco antagonist, suggesting that odorant mediated behaviors can be manipulated through Orco

  6. An olfactory receptor from Apolygus lucorum (Meyer-Dur) mainly tuned to volatiles from flowering host plants.

    PubMed

    Yan, Shu-Wei; Zhang, Jin; Liu, Yang; Li, Guo-Qing; Wang, Gui-Rong

    2015-08-01

    Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is one of the most serious agricultural pests, feeding on a wide range of cultivated plants, including cotton, cereals and vegetables in the north of China. This insect can frequently switch between habitats and host plants over seasons and prefer plants in bloom. A. lucorum relies heavily on olfaction to locate its host plants finely discriminating different plant volatiles in the environment. Despite its economical importance, research on the olfactory system of this species has been so far very limited. In this study, we have identified and characterized an olfactory receptor which is sensitively tuned to (Z)-3-Hexenyl acetate and several flowering compounds. Besides being present in the bouquet of some flowers, these compounds are produced by plants that have suffered attacks and are supposed to act as chemical messengers between plants. This OR may play an important role in the selection of host plants.

  7. An olfactory receptor from Apolygus lucorum (Meyer-Dur) mainly tuned to volatiles from flowering host plants.

    PubMed

    Yan, Shu-Wei; Zhang, Jin; Liu, Yang; Li, Guo-Qing; Wang, Gui-Rong

    2015-08-01

    Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is one of the most serious agricultural pests, feeding on a wide range of cultivated plants, including cotton, cereals and vegetables in the north of China. This insect can frequently switch between habitats and host plants over seasons and prefer plants in bloom. A. lucorum relies heavily on olfaction to locate its host plants finely discriminating different plant volatiles in the environment. Despite its economical importance, research on the olfactory system of this species has been so far very limited. In this study, we have identified and characterized an olfactory receptor which is sensitively tuned to (Z)-3-Hexenyl acetate and several flowering compounds. Besides being present in the bouquet of some flowers, these compounds are produced by plants that have suffered attacks and are supposed to act as chemical messengers between plants. This OR may play an important role in the selection of host plants. PMID:26050917

  8. NanoCAGE analysis of the mouse olfactory epithelium identifies the expression of vomeronasal receptors and of proximal LINE elements

    PubMed Central

    Pascarella, Giovanni; Lazarevic, Dejan; Plessy, Charles; Bertin, Nicolas; Akalin, Altuna; Vlachouli, Christina; Simone, Roberto; Faulkner, Geoffrey J.; Zucchelli, Silvia; Kawai, Jun; Daub, Carsten O.; Hayashizaki, Yoshihide; Lenhard, Boris; Carninci, Piero; Gustincich, Stefano

    2013-01-01

    By coupling laser capture microdissection to nanoCAGE technology and next-generation sequencing we have identified the genome-wide collection of active promoters in the mouse Main Olfactory Epithelium (MOE). Transcription start sites (TSSs) for the large majority of Olfactory Receptors (ORs) have been previously mapped increasing our understanding of their promoter architecture. Here we show that in our nanoCAGE libraries of the mouse MOE we detect a large number of tags mapped in loci hosting Type-1 and Type-2 Vomeronasal Receptors genes (V1Rs and V2Rs). These loci also show a massive expression of Long Interspersed Nuclear Elements (LINEs). We have validated the expression of selected receptors detected by nanoCAGE with in situ hybridization, RT-PCR and qRT-PCR. This work extends the repertory of receptors capable of sensing chemical signals in the MOE, suggesting intriguing interplays between MOE and VNO for pheromone processing and positioning transcribed LINEs as candidate regulatory RNAs for VRs expression. PMID:24600346

  9. Exchanging ligand-binding specificity between a pair of mouse olfactory receptor paralogs reveals odorant recognition principles.

    PubMed

    Baud, Olivia; Yuan, Shuguang; Veya, Luc; Filipek, Slawomir; Vogel, Horst; Pick, Horst

    2015-01-01

    A multi-gene family of ~1000 G protein-coupled olfactory receptors (ORs) constitutes the molecular basis of mammalian olfaction. Due to the lack of structural data its remarkable capacity to detect and discriminate thousands of odorants remains poorly understood on the structural level of the receptor. Using site-directed mutagenesis we transferred ligand specificity between two functionally related ORs and thereby revealed amino acid residues of central importance for odorant recognition and discrimination of the two receptors. By exchanging two of three residues, differing at equivalent positions of the putative odorant binding site between the mouse OR paralogs Olfr73 (mOR-EG) and Olfr74 (mOR-EV), we selectively changed ligand preference but remarkably also signaling activation strength in both ORs. Computer modeling proposed structural details at atomic resolution how the very same odorant molecule might interact with different contact residues to induce different functional responses in two related receptors. Our findings provide a mechanistic explanation of how the olfactory system distinguishes different molecular aspects of a given odorant molecule, and unravel important molecular details of the combinatorial encoding of odorant identity at the OR level.

  10. Exchanging ligand-binding specificity between a pair of mouse olfactory receptor paralogs reveals odorant recognition principles.

    PubMed

    Baud, Olivia; Yuan, Shuguang; Veya, Luc; Filipek, Slawomir; Vogel, Horst; Pick, Horst

    2015-01-01

    A multi-gene family of ~1000 G protein-coupled olfactory receptors (ORs) constitutes the molecular basis of mammalian olfaction. Due to the lack of structural data its remarkable capacity to detect and discriminate thousands of odorants remains poorly understood on the structural level of the receptor. Using site-directed mutagenesis we transferred ligand specificity between two functionally related ORs and thereby revealed amino acid residues of central importance for odorant recognition and discrimination of the two receptors. By exchanging two of three residues, differing at equivalent positions of the putative odorant binding site between the mouse OR paralogs Olfr73 (mOR-EG) and Olfr74 (mOR-EV), we selectively changed ligand preference but remarkably also signaling activation strength in both ORs. Computer modeling proposed structural details at atomic resolution how the very same odorant molecule might interact with different contact residues to induce different functional responses in two related receptors. Our findings provide a mechanistic explanation of how the olfactory system distinguishes different molecular aspects of a given odorant molecule, and unravel important molecular details of the combinatorial encoding of odorant identity at the OR level. PMID:26449412

  11. Exchanging ligand-binding specificity between a pair of mouse olfactory receptor paralogs reveals odorant recognition principles

    PubMed Central

    Baud, Olivia; Yuan, Shuguang; Veya, Luc; Filipek, Slawomir; Vogel, Horst; Pick, Horst

    2015-01-01

    A multi-gene family of ~1000 G protein-coupled olfactory receptors (ORs) constitutes the molecular basis of mammalian olfaction. Due to the lack of structural data its remarkable capacity to detect and discriminate thousands of odorants remains poorly understood on the structural level of the receptor. Using site-directed mutagenesis we transferred ligand specificity between two functionally related ORs and thereby revealed amino acid residues of central importance for odorant recognition and discrimination of the two receptors. By exchanging two of three residues, differing at equivalent positions of the putative odorant binding site between the mouse OR paralogs Olfr73 (mOR-EG) and Olfr74 (mOR-EV), we selectively changed ligand preference but remarkably also signaling activation strength in both ORs. Computer modeling proposed structural details at atomic resolution how the very same odorant molecule might interact with different contact residues to induce different functional responses in two related receptors. Our findings provide a mechanistic explanation of how the olfactory system distinguishes different molecular aspects of a given odorant molecule, and unravel important molecular details of the combinatorial encoding of odorant identity at the OR level. PMID:26449412

  12. Degeneration of olfactory receptor gene repertories in primates: no direct link to full trichromatic vision.

    PubMed

    Matsui, Atsushi; Go, Yasuhiro; Niimura, Yoshihito

    2010-05-01

    Odor molecules in the environment are detected by olfactory receptors (ORs), being encoded by a large multigene family in mammalian genomes. It is generally thought that primates are vision oriented and dependent weakly on olfaction. Previous studies suggested that Old World monkeys (OWMs) and hominoids lost many functional OR genes after the divergence from New World monkeys (NWMs) due to the acquisition of well-developed trichromatic vision. To examine this hypothesis, here we analyzed OR gene repertoires of five primate species including NWMs, OWMs, and hominoids for which high-coverage genome sequences are available, together with two prosimians and tree shrews with low-coverage genomes. The results showed no significant differences in the number of functional OR genes between NWMs (marmosets) and OWMs/hominoids. Two independent analyses, identification of orthologous genes among the five primates and estimation of the numbers of ancestral genes by the reconciled tree method, did not support a sudden loss of OR genes at the branch of the OWMs/hominoids ancestor but suggested a gradual loss in every lineage. Moreover, we found that humans retain larger numbers of ancestral OR genes that were in the common ancestor of NWMs/OWMs/hominoids than orangutans and macaques and that the OR gene repertoire in humans is more similar to that of marmosets than those of orangutans and macaques. These results suggest that the degeneration of OR genes in primates cannot simply be explained by the acquisition of trichromatic vision, and our sense of smell may not be inferior to other primate species. PMID:20061342

  13. Odorant-induced currents in intact patches from rat olfactory receptor neurons: theory and experiment.

    PubMed Central

    Chiu, P; Lynch, J W; Barry, P H

    1997-01-01

    Odorant-induced currents in mammalian olfactory receptor neurons have proved difficult to obtain reliably using conventional whole-cell recording. By using a mathematical model of the electrical circuit of the patch and rest-of-cell, we demonstrate how cell-attached patch measurements can be used to quantitatively analyze responses to odorants or a high (100 mM) K+ solution. High K+ induced an immediate current flux from cell to pipette, which was modeled as a depolarization of approximately 52 mV, close to that expected from the Nernst equation (56 mV), and no change in the patch conductance. By contrast, a cocktail of cAMP-stimulating odorants induced a current flux from pipette into cell following a significant (4-10 s) delay. This was modeled as an average patch conductance increase of 36 pS and a depolarization of 13 mV. Odorant-induced single channels had a conductance of 16 pS. In cells bathed with no Mg2+ and 0.25 mM Ca2+, odorants induced a current flow from cell to pipette, which was modeled as a patch conductance increase of approximately 115 pS and depolarization of approximately 32 mV. All these results are consistent with cAMP-gated cation channels dominating the odorant response. This approach, which provides useful estimates of odorant-induced voltage and conductance changes, is applicable to similar measurements in any small cells. Images FIGURE 1 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE A1 PMID:9138590

  14. Potential role of transient receptor potential channel M5 in sensing putative pheromones in mouse olfactory sensory neurons.

    PubMed

    Oshimoto, Arisa; Wakabayashi, Yoshihiro; Garske, Anna; Lopez, Roberto; Rolen, Shane; Flowers, Michael; Arevalo, Nicole; Restrepo, Diego

    2013-01-01

    Based on pharmacological studies of chemosensory transduction in transient receptor potential channel M5 (TRPM5) knockout mice it was hypothesized that this channel is involved in transduction for a subset of putative pheromones in mouse olfactory sensory neurons (OSNs). Yet, in the same study an electroolfactogram (EOG) in the mouse olfactory epithelium showed no significant difference in the responses to pheromones (and odors) between wild type and TRPM5 knockout mice. Here we show that the number of OSNs expressing TRPM5 is increased by unilateral naris occlusion. Importantly, EOG experiments show that mice lacking TRPM5 show a decreased response in the occluded epithelia to putative pheromones as opposed to wild type mice that show no change upon unilateral naris occlusion. This evidence indicates that under decreased olfactory sensory input TRPM5 plays a role in mediating putative pheromone transduction. Furthermore, we demonstrate that cyclic nucleotide gated channel A2 knockout (CNGA2-KO) mice that show substantially decreased or absent responses to odors and pheromones also have elevated levels of TRPM5 compared to wild type mice. Taken together, our evidence suggests that TRPM5 plays a role in mediating transduction for putative pheromones under conditions of reduced chemosensory input.

  15. Molecular characterization and expression profiles of olfactory receptor genes in the parasitic wasp, Microplitis mediator (Hymenoptera: Braconidae).

    PubMed

    Ma, Long; Gu, Shao-Hua; Liu, Ze-Wen; Wang, Shan-Ning; Guo, Yu-Yuan; Zhou, Jing-Jiang; Zhang, Yong-Jun

    2014-01-01

    Olfactory receptors (OR) are believed to fulfil an indispensable role in insects host-seeking, mating and ovipositing. We obtained 4785 high-quality expressed sequencing tags (EST) from the antennal cDNA library of the parasitic wasp Microplitis mediator, a natural enemy of crop pests. After assembling, 786 contigs and 2130 singletons were generated. Using BLAST searches, a number of olfactory-related genes were identified, including ESTs encoding for 25 ORs. 14 full-length OR genes were cloned and their expression profiles in the wasp olfactory organs were quantified by real-time qRT-PCR. The results indicated a diverse distribution between the tissues and genders, yet the majority of OR genes are highly expressed in antennae. Three OR genes (Or2, Or12 and Or13) are highly expressed in female antennae, eight OR genes (ORco, Or3, Or4, Or5, Or7, Or8, Or9 and Or11) are highly expressed in male antennae. This is the first report on tissue-specific expression of wasp OR genes. Our study provides a foundational knowledge to explore and understand the molecular basis of odorant reception in this parasitic wasp and for the study of trophic interactions of natural enemy. PMID:24291166

  16. Phylogeny of the vomeronasal system and of receptor cell types in the olfactory and vomeronasal epithelia of vertebrates.

    PubMed

    Eisthen, H L

    1992-10-01

    In this paper, the evolutionary origin of the vomeronasal system as a discrete sensory system separate from olfaction is examined. The presence of a discrete vomeronasal system appears to be a derived character in tetrapods, and its presence in larval amphibians indicates that the system did not arise as a terrestrial adaptation. The vomeronasal system has been lost independently in several taxa, including crocodilians, some bats, cetaceans, and some primates. The presence of microvillar receptor cells in the vomeronasal epithelium appears to be the ancestral condition for tetrapods, and alternative hypotheses concerning the ancestral condition for receptor cell types in the vertebrate olfactory epithelium are discussed. Finally, the possibility that the vomeronasal system is present in some fishes in a form that has not been recognized is discussed in relation to the phylogenetic distribution of receptor cell types in vertebrates. PMID:1392068

  17. Structure of the olfactory receptor organs, their GABAergic neural pathways, and modulation of mating behavior, in the giant freshwater prawn, Macrobrachium rosenbergii.

    PubMed

    Kruangkum, Thanapong; Chotwiwatthanakun, Charoonroj; Vanichviriyakit, Rapeepun; Tinikul, Yotsawan; Anuracpreeda, Panat; Wanichanon, Chaitip; Hanna, Peter J; Sobhon, Prasert

    2013-06-01

    In the giant male prawn, Macrobrachium rosenbergii, the olfactory system is thought to be the main pathway for modulating sexual behavior through pheromone perception. In this report, we first used gross anatomical, histological, and SEM methods to describe the structures of the olfactory receptors (sensilla setae), their neural pathways, and possible role in modulating mating behavior. On the surfaces of antennule and antenna filaments there are four types of sensory receptors, viz single spike-like setae, single flagellum-like setae, multiple flagella-like setae, and aesthetascs (ASs). The ASs, which had previously been proposed to be odor receptor setae, are found only on the short filament of lateral antennule (slAn). Each AS on the slAn connects with olfactory receptor neurons (ORNs), whose axons form an outer central antennule nerve (ocAnNv), which then connects with the olfactory neutrophil (ON) of the brain. Thus, the slAn is the major olfactory organ that conveys sensory inputs from each AS to the ON within the deutocerebrum. GABA immunoreactivity was present in ASs, neurons of ORNs, inner central antennular, lateral tegumentary nerve, ocAnNv and the ON, inferring that GABA is the likely neurotransmitter in modulating olfaction. Disruption of the slAn by ablation or covering with Vaseline, resulted in significant reduction of mating behavior, indicating that this organ is crucial for sex pheromone perception. Identification of the active pheromones and further bioassays are now being performed.

  18. Properties of transient K+ currents and underlying single K+ channels in rat olfactory receptor neurons

    PubMed Central

    1991-01-01

    The transient potassium current, IK(t), of enzymatically dissociated rat olfactory receptor neurons was studied using patch-clamp techniques. Upon depolarization from negative holding potentials, IK(t) activated rapidly and then inactivated with a time course described by the sum of two exponential components with time constants of 22.4 and 143 ms. Single-channel analysis revealed a further small component with a time constant of several seconds. Steady-state inactivation was complete at -20 mV and completely removed at -80 mV (midpoint -45 mV). Activation was significant at -40 mV and appeared to reach a maximum conductance at +40 mV (midpoint -13 mV). Deactivation was described by the sum of two voltage-dependent exponential components. Recovery from inactivation was extraordinarily slow (50 s at -100 mV) and the underlying processes appeared complex. IK(t) was reduced by 4- aminopyridine and tetraethylammonium applied externally. Increasing the external K+ concentration ([K+]o) from 5 to 25 mM partially removed IK(t) inactivation, usually without affecting activation kinetics. The elevated [K+]o also hyperpolarized the steady-state inactivation curve by 9 mV and significantly depolarized the voltage dependence of activation. Single transient K+ channels, with conductances of 17 and 26 pS, were observed in excised patches and often appeared to be localized into large clusters. These channels were similar to IK(t) in their kinetic, pharmacological, and voltage-dependent properties and their inactivation was also subject to modulation by [K+]o. The properties of IK(t) imply a role in action potential repolarization and suggest it may also be important in modulating spike parameters during neuronal burst firing. A simple method is also presented to correct for errors in the measurement of whole-cell resistance (Ro) that can result when patch-clamping very small cells. The analysis revealed a mean corrected Ro of 26 G omega for these cells. PMID:1865174

  19. Changes in Olfactory Receptor Expression Are Correlated With Odor Exposure During Early Development in the zebrafish (Danio rerio).

    PubMed

    Calfún, Cristian; Domínguez, Calixto; Pérez-Acle, Tomás; Whitlock, Kathleen E

    2016-05-01

    We have previously shown that exposure to phenyl ethyl alcohol (PEA) causes an increase in the expression of the transcription factor otx2 in the olfactory epithelium (OE) of juvenile zebrafish, and this change is correlated with the formation of an odor memory of PEA. Here, we show that the changes in otx2 expression are specific to βPEA: exposure to αPEA did not affect otx2 expression. We identified 34 olfactory receptors (ORs) representing 16 families on 4 different chromosomes as candidates for direct regulation of OR expression via Otx2. Subsequent in silico analysis uncovered Hnf3b binding sites closely associated with Otx2 binding sites in the regions flanking the ORs. Analysis by quantitative polymerase chain reaction and RNA-seq of OR expression in developing zebrafish exposed to different isoforms of PEA showed that a subset of ORs containing both Otx2/Hnf3b binding sites were downregulated only in βPEA-exposed juveniles and this change persisted through adult life. Localization of OR expression by in situ hybridization indicates the downregulation occurs at the level of RNA and not the number of cells expressing a given receptor. Finally, analysis of immediate early gene expression in the OE did not reveal changes in c-fos expression in response to either αPEA or βPEA. PMID:26892307

  20. Global Survey of Variation in a Human Olfactory Receptor Gene Reveals Signatures of Non-Neutral Evolution.

    PubMed

    Hoover, Kara C; Gokcumen, Omer; Qureshy, Zoya; Bruguera, Elise; Savangsuksa, Aulaphan; Cobb, Matthew; Matsunami, Hiroaki

    2015-09-01

    Allelic variation at 4 loci in the human olfactory receptor gene OR7D4 is associated with perceptual variation in the sex steroid-derived odorants, androstenone, and androstadienone. Androstadienone has been linked with chemosensory identification whereas androstenone makes pork from uncastrated pigs distasteful ("boar taint"). In a sample of 2224 individuals from 43 populations, we identified 45 OR7D4 single nucleotide polymorphisms. Coalescent modeling of frequency-site-spectrum-based statistics identified significant deviation from neutrality in human OR7D4; individual populations with statistically significant deviations from neutrality include Gujarati, Beijing Han, Great Britain, Iberia, and Puerto Rico. Analysis of molecular variation values indicated statistically significant population differentiation driven mainly by the 4 alleles associated with androstenone perception variation; however, fixation values were low suggesting that genetic structure may not have played a strong role in creating these group divisions. We also studied OR7D4 in the genomes of extinct members of the human lineage: Altai Neandertal and Denisovan. No variants were identified in Altai but 2 were in Denisova, one of which is shared by modern humans and one of which is novel. A functional test of modern human and a synthesized mutant Denisova OR7D4 indicated no statistically significant difference in responses to androstenone between the 2 species. Our results suggest non-neutral evolution for an olfactory receptor gene.

  1. Global Survey of Variation in a Human Olfactory Receptor Gene Reveals Signatures of Non-Neutral Evolution.

    PubMed

    Hoover, Kara C; Gokcumen, Omer; Qureshy, Zoya; Bruguera, Elise; Savangsuksa, Aulaphan; Cobb, Matthew; Matsunami, Hiroaki

    2015-09-01

    Allelic variation at 4 loci in the human olfactory receptor gene OR7D4 is associated with perceptual variation in the sex steroid-derived odorants, androstenone, and androstadienone. Androstadienone has been linked with chemosensory identification whereas androstenone makes pork from uncastrated pigs distasteful ("boar taint"). In a sample of 2224 individuals from 43 populations, we identified 45 OR7D4 single nucleotide polymorphisms. Coalescent modeling of frequency-site-spectrum-based statistics identified significant deviation from neutrality in human OR7D4; individual populations with statistically significant deviations from neutrality include Gujarati, Beijing Han, Great Britain, Iberia, and Puerto Rico. Analysis of molecular variation values indicated statistically significant population differentiation driven mainly by the 4 alleles associated with androstenone perception variation; however, fixation values were low suggesting that genetic structure may not have played a strong role in creating these group divisions. We also studied OR7D4 in the genomes of extinct members of the human lineage: Altai Neandertal and Denisovan. No variants were identified in Altai but 2 were in Denisova, one of which is shared by modern humans and one of which is novel. A functional test of modern human and a synthesized mutant Denisova OR7D4 indicated no statistically significant difference in responses to androstenone between the 2 species. Our results suggest non-neutral evolution for an olfactory receptor gene. PMID:26072518

  2. Global Survey of Variation in a Human Olfactory Receptor Gene Reveals Signatures of Non-Neutral Evolution

    PubMed Central

    Gokcumen, Omer; Qureshy, Zoya; Bruguera, Elise; Savangsuksa, Aulaphan; Cobb, Matthew; Matsunami, Hiroaki

    2015-01-01

    Allelic variation at 4 loci in the human olfactory receptor gene OR7D4 is associated with perceptual variation in the sex steroid-derived odorants, androstenone, and androstadienone. Androstadienone has been linked with chemosensory identification whereas androstenone makes pork from uncastrated pigs distasteful (“boar taint”). In a sample of 2224 individuals from 43 populations, we identified 45 OR7D4 single nucleotide polymorphisms. Coalescent modeling of frequency-site-spectrum-based statistics identified significant deviation from neutrality in human OR7D4; individual populations with statistically significant deviations from neutrality include Gujarati, Beijing Han, Great Britain, Iberia, and Puerto Rico. Analysis of molecular variation values indicated statistically significant population differentiation driven mainly by the 4 alleles associated with androstenone perception variation; however, fixation values were low suggesting that genetic structure may not have played a strong role in creating these group divisions. We also studied OR7D4 in the genomes of extinct members of the human lineage: Altai Neandertal and Denisovan. No variants were identified in Altai but 2 were in Denisova, one of which is shared by modern humans and one of which is novel. A functional test of modern human and a synthesized mutant Denisova OR7D4 indicated no statistically significant difference in responses to androstenone between the 2 species. Our results suggest non-neutral evolution for an olfactory receptor gene. PMID:26072518

  3. Functional promiscuity in a mammalian chemosensory system: extensive expression of vomeronasal receptors in the main olfactory epithelium of mouse lemurs

    PubMed Central

    Hohenbrink, Philipp; Dempewolf, Silke; Zimmermann, Elke; Mundy, Nicholas I.; Radespiel, Ute

    2014-01-01

    The vomeronasal organ (VNO) is functional in most terrestrial mammals, though progressively reduced in the primate lineage, and is used for intraspecific communication and predator recognition. Vomeronasal receptor (VR) genes comprise two families of chemosensory genes (V1R and V2R) that have been considered to be specific for the VNO. However, recently a large number of VRs were reported to be expressed in the main olfactory epithelium (MOE) of mice, but there is little knowledge of the expression of these genes outside of rodents. To explore the function of VR genes in mammalian evolution, we analyzed and compared the expression of 64 V1R and 2 V2R genes in the VNO and the MOE of the gray mouse lemur (Microcebus murinus), the primate with the largest known VR repertoire. We furthermore compared expression patterns in adults of both sexes and seasons, and in an infant. A large proportion (83–97%) of the VR loci was expressed in the VNO of all individuals. The repertoire in the infant was as rich as in adults, indicating reliance on olfactory communication from early postnatal development onwards. In concordance with mice, we also detected extensive expression of VRs in the MOE, with proportions of expressed loci in individuals ranging from 29 to 45%. TRPC2, which encodes a channel protein crucial for signal transduction via VRs, was co-expressed in the MOE in all individuals indicating likely functionality of expressed VR genes in the MOE. In summary, the large VR repertoire in mouse lemurs seems to be highly functional. Given the differences in the neural pathways of MOE and VNO signals, which project to higher cortical brain centers or the limbic system, respectively, this raises the intriguing possibility that the evolution of MOE-expression of VRs enabled mouse lemurs to adaptively diversify the processing of VR-encoded olfactory information. PMID:25309343

  4. The vestigial olfactory receptor subgenome of odontocete whales: phylogenetic congruence between gene-tree reconciliation and supermatrix methods.

    PubMed

    McGowen, Michael R; Clark, Clay; Gatesy, John

    2008-08-01

    The macroevolutionary transition of whales (cetaceans) from a terrestrial quadruped to an obligate aquatic form involved major changes in sensory abilities. Compared to terrestrial mammals, the olfactory system of baleen whales is dramatically reduced, and in toothed whales is completely absent. We sampled the olfactory receptor (OR) subgenomes of eight cetacean species from four families. A multigene tree of 115 newly characterized OR sequences from these eight species and published data for Bos taurus revealed a diverse array of class II OR paralogues in Cetacea. Evolution of the OR gene superfamily in toothed whales (Odontoceti) featured a multitude of independent pseudogenization events, supporting anatomical evidence that odontocetes have lost their olfactory sense. We explored the phylogenetic utility of OR pseudogenes in Cetacea, concentrating on delphinids (oceanic dolphins), the product of a rapid evolutionary radiation that has been difficult to resolve in previous studies of mitochondrial DNA sequences. Phylogenetic analyses of OR pseudogenes using both gene-tree reconciliation and supermatrix methods yielded fully resolved, consistently supported relationships among members of four delphinid subfamilies. Alternative minimizations of gene duplications, gene duplications plus gene losses, deep coalescence events, and nucleotide substitutions plus indels returned highly congruent phylogenetic hypotheses. Novel DNA sequence data for six single-copy nuclear loci and three mitochondrial genes (> 5000 aligned nucleotides) provided an independent test of the OR trees. Nucleotide substitutions and indels in OR pseudogenes showed a very low degree of homoplasy in comparison to mitochondrial DNA and, on average, provided more variation than single-copy nuclear DNA. Our results suggest that phylogenetic analysis of the large OR superfamily will be effective for resolving relationships within Cetacea whether supermatrix or gene-tree reconciliation procedures are

  5. Neonatal olfactory bulbectomy enhances locomotor activity, exploratory behavior and binding of NMDA receptors in pre-pubertal rats.

    PubMed

    Flores, G; Ibañez-Sandoval, O; Silva-Gómez, A B; Camacho-Abrego, I; Rodríguez-Moreno, A; Morales-Medina, J C

    2014-02-14

    In this study, we investigated the effect of neonatal olfactory bulbectomy (nOBX) on behavioral paradigms related to olfaction such as exploratory behavior, locomotor activity in a novel environment and social interaction. We also studied the effect of nOBX on the activity of the N-methyl-d-aspartate (NMDA) subtype of glutamate receptors during development. The behavioral effects of nOBX (postnatal day 7, PD7) were investigated in pre- (PD30) and post-pubertal (PD60) Wistar rats. NMDA receptor activity was measured with [(125)I]MK-801 in the brain regions associated with the olfactory circuitry. A significant increase in the novelty-induced locomotion was seen in the pre-pubertal nOBX rats. Although the locomotor effect was less marked than in pre-pubertal rats, the nOBX rats tested post-pubertally failed to habituate to the novel situation as quickly as the sham- and normal- controls. Pre-pubertally, the head-dipping behavior was enhanced in nOBX rats compared with sham-operated and normal controls, while normal exploratory behavior was observed between groups in adulthood. In contrast, social interaction was increased in post-pubertal animals that underwent nOBX. Both pre- and post-pubertal nOBX rats recovered olfaction. Interestingly, pre-pubertal rats showed a significant increase in the [(125)I]MK-801 binding in the piriform cortex, dorsal hippocampus, inner and outer layers of the frontal cortex and outer layer of the cingulate cortex. At post-pubertal age, no significant differences in [(125)I]MK-801 binding were observed between groups at any of the brain regions analyzed. These results suggest that nOBX produces pre-pubertal behavioral disturbances and NMDA receptor changes that are transitory with recovery of olfaction early in adulthood. PMID:24295633

  6. Neonatal olfactory bulbectomy enhances locomotor activity, exploratory behavior and binding of NMDA receptors in pre-pubertal rats.

    PubMed

    Flores, G; Ibañez-Sandoval, O; Silva-Gómez, A B; Camacho-Abrego, I; Rodríguez-Moreno, A; Morales-Medina, J C

    2014-02-14

    In this study, we investigated the effect of neonatal olfactory bulbectomy (nOBX) on behavioral paradigms related to olfaction such as exploratory behavior, locomotor activity in a novel environment and social interaction. We also studied the effect of nOBX on the activity of the N-methyl-d-aspartate (NMDA) subtype of glutamate receptors during development. The behavioral effects of nOBX (postnatal day 7, PD7) were investigated in pre- (PD30) and post-pubertal (PD60) Wistar rats. NMDA receptor activity was measured with [(125)I]MK-801 in the brain regions associated with the olfactory circuitry. A significant increase in the novelty-induced locomotion was seen in the pre-pubertal nOBX rats. Although the locomotor effect was less marked than in pre-pubertal rats, the nOBX rats tested post-pubertally failed to habituate to the novel situation as quickly as the sham- and normal- controls. Pre-pubertally, the head-dipping behavior was enhanced in nOBX rats compared with sham-operated and normal controls, while normal exploratory behavior was observed between groups in adulthood. In contrast, social interaction was increased in post-pubertal animals that underwent nOBX. Both pre- and post-pubertal nOBX rats recovered olfaction. Interestingly, pre-pubertal rats showed a significant increase in the [(125)I]MK-801 binding in the piriform cortex, dorsal hippocampus, inner and outer layers of the frontal cortex and outer layer of the cingulate cortex. At post-pubertal age, no significant differences in [(125)I]MK-801 binding were observed between groups at any of the brain regions analyzed. These results suggest that nOBX produces pre-pubertal behavioral disturbances and NMDA receptor changes that are transitory with recovery of olfaction early in adulthood.

  7. Reading Out Olfactory Receptors: Feedforward Circuits Detect Odors in Mixtures without Demixing.

    PubMed

    Mathis, Alexander; Rokni, Dan; Kapoor, Vikrant; Bethge, Matthias; Murthy, Venkatesh N

    2016-09-01

    The olfactory system, like other sensory systems, can detect specific stimuli of interest amidst complex, varying backgrounds. To gain insight into the neural mechanisms underlying this ability, we imaged responses of mouse olfactory bulb glomeruli to mixtures. We used this data to build a model of mixture responses that incorporated nonlinear interactions and trial-to-trial variability and explored potential decoding mechanisms that can mimic mouse performance when given glomerular responses as input. We find that a linear decoder with sparse weights could match mouse performance using just a small subset of the glomeruli (∼15). However, when such a decoder is trained only with single odors, it generalizes poorly to mixture stimuli due to nonlinear mixture responses. We show that mice similarly fail to generalize, suggesting that they learn this segregation task discriminatively by adjusting task-specific decision boundaries without taking advantage of a demixed representation of odors. PMID:27593177

  8. Differential Octopaminergic Modulation of Olfactory Receptor Neuron Responses to Sex Pheromones in Heliothis virescens

    PubMed Central

    Hillier, N. Kirk; Kavanagh, Rhys M. B.

    2015-01-01

    Octopamine is an important neuromodulator of neural function in invertebrates. Octopamine increases male moth sensitivity to female sex pheromones, however, relatively little is known as to the role of octopamine in the female olfactory system, nor its possible effects on the reception of non-pheromone odorants. The purpose of this study was to determine relative effects of octopamine on the sensitivity of the peripheral olfactory system in male and female Heliothis virescens. Single sensillum recording was conducted in both sexes following injection with octopamine or Ringer solution, and during odorant stimulation with conspecific female sex pheromone or host plant volatiles. Results indicate that octopamine plays a significant modulatory role in female sex pheromone detection in female moths; and that male and female pheromone detection neurons share distinct pharmacological and physiological similarities in H. virescens despite sexual dimorphism at the antennal level. PMID:26650832

  9. Specific mesenchymal/epithelial induction of olfactory receptor, vomeronasal, and gonadotropin-releasing hormone (GnRH) neurons

    PubMed Central

    Rawson, N.E; Lischka, F. W.; Yee, K.K.; Peters, A.Z.; Tucker, E.S.; Meechan, D.W.; Zirlinger, M.; Maynard, T.M.; Burd, G.B.; Dulac, C.; Pevny, L.; LaMantia, A-S.

    2013-01-01

    We asked whether specific mesenchymal/epithelial (M/E) induction generates olfactory receptor neurons (ORNs), vomeronasal neurons (VRNs) and gonadotropin releasing hormone (GnRH) neurons—the major neuron classes associated with the olfactory epithelium (OE). To assess specificity of M/E-mediated neurogenesis, we compared the influence of frontonasal mesenchyme on frontonasal epithelium, which becomes the OE, with that of the forelimb bud. Despite differences in position, morphogenetic and cytogenic capacity, both mesenchymal tissues support neurogenesis, expression of several signaling molecules and neurogenic transcription factors in the frontonasal epithelium. Only frontonasal mesenchyme, however, supports OE-specific patterning and activity of a subset of signals and factors associated with OE differentiation. Moreover, only appropriate pairing of frontonasal epithelial and mesenchymal partners yields ORNs, VRNs, and GnRH neurons. Accordingly, the position and molecular identity of specialized frontonasal epithelia and mesenchyme early in gestation and subsequent inductive interactions, specifies the genesis and differentiation of peripheral chemosensory and neuroendocrine neurons. PMID:20503368

  10. Sensillar expression and responses of olfactory receptors reveal different peripheral coding in two Helicoverpa species using the same pheromone components

    PubMed Central

    Chang, Hetan; Guo, Mengbo; Wang, Bing; Liu, Yang; Dong, Shuanglin; Wang, Guirong

    2016-01-01

    Male moths efficiently recognize conspecific sex pheromones thanks to their highly accurate and specific olfactory system. The Heliothis/Helicoverpa species are regarded as good models for studying the perception of sex pheromones. In this study, we performed a series of experiments to investigate the peripheral mechanisms of pheromone coding in two-closely related species, Helicoverpa armigera and H. assulta. The morphology and distribution patterns of sensilla trichoidea are similar between the two species when observed at the scanning electron microscope, but their performances are different. In H. armigera, three functional types of sensilla trichoidea (A, B and C) were found to respond to different pheromone components, while in H. assulta only two types of such sensilla (A and C) could be detected. The response profiles of all types of sensilla trichoidea in the two species well matched the specificities of the pheromone receptors (PRs) expressed in the same sensilla, as measured in voltage-clamp experiments. The expressions of PRs in neighboring olfactory sensory neurons (OSNs) within the same trichoid sensillum were further confirmed by in situ hybridization. Our results show how the same pheromone components can code for different messages at the periphery of two Helicoverpa species. PMID:26744070

  11. Neuropeptide S ameliorates olfactory spatial memory impairment induced by scopolamine and MK801 through activation of cognate receptor-expressing neurons in the subiculum complex.

    PubMed

    Shao, Yu-Feng; Wang, Can; Xie, Jun-Fan; Kong, Xiang-Pan; Xin, Le; Dong, Chao-Yu; Li, Jing; Ren, Wen-Ting; Hou, Yi-Ping

    2016-07-01

    Our previous studies have demonstrated that neuropeptide S (NPS), via selective activation of the neurons bearing NPS receptor (NPSR) in the olfactory cortex, facilitates olfactory function. High level expression of NPSR mRNA in the subiculum complex of hippocampal formation suggests that NPS-NPSR system might be involved in the regulation of olfactory spatial memory. The present study was undertaken to investigate effects of NPS on the scopolamine- or MK801-induced impairment of olfactory spatial memory using computer-assisted 4-hole-board spatial memory test, and by monitoring Fos expression in the subiculum complex in mice. In addition, dual-immunofluorescence microscopy was employed to identify NPS-induced Fos-immunereactive (-ir) neurons that also bear NPSR. Intracerebroventricular administration of NPS (0.5 nmol) significantly increased the number of visits to switched odorants in recall trial in mice suffering from odor-discriminating inability induced by scopolamine, a selective muscarinic cholinergic receptor antagonist, or MK801, a N-methyl-D-aspartate receptor antagonist, after training trials. The improvement of olfactory spatial memory by NPS was abolished by the NPSR antagonist [D-Val(5)]NPS (40 nmol). Ex vivo c-Fos and NPSR immunohistochemistry revealed that, as compared with vehicle-treated mice, NPS markedly enhanced Fos expression in the subiculum complex encompassing the subiculum (S), presubiculum (PrS) and parasubiculum (PaS). The percentages of Fos-ir neurons that also express NPSR were 91.3, 86.5 and 90.0 % in the S, PrS and PaS, respectively. The present findings demonstrate that NPS, via selective activation of the neurons bearing NPSR in the subiculum complex, ameliorates olfactory spatial memory impairment induced by scopolamine and MK801 in mice.

  12. Bioelectronic nose with high sensitivity and selectivity using chemically functionalized carbon nanotube combined with human olfactory receptor.

    PubMed

    Lee, Sang Hun; Jin, Hye Jun; Song, Hyun Seok; Hong, Seunghun; Park, Tai Hyun

    2012-02-20

    Single-walled carbon nanotubes (swCNTs) hold great promise for use as molecular wires because they exhibit high electrical conductivity and chemical stability. However, constructing swCNT-based transducer devices requires controlled strategies for assembling biomolecules on swCNTs. In this study, we proposed a chemically modified swCNT. The swCNT was functionalized with 1,5-diaminonaphthalene via π-stacking, for reliable attachment of the human olfactory receptor 2AG1 (hOR2AG1). The human olfactory receptor was then anchored. We investigated the use of this functionalized CNT in the fabrication of a highly sensitive and selective bioelectronic nose. For the bioelectronic nose, the swCNT-field effect transistor (FET) platform was composed of polyethylene glycol (PEG)-coated regions to prevent non-specific absorption and chemically modified swCNTs regions containing hOR2AG1, which can bind to the specific odorant. This approach allowed us to create well-defined micron-scale patterns of hOR2AG1 on the swCNTs. Our bioelectronic nose displayed ultrahigh sensitivity down to concentrations as low as 1fM due to the enhanced hOR2AG1-odorant interaction through the tight binding of hOR2AG1 on the chemically modified swCNTs. In addition, the approach described here may provide an alternative route for multiplexed detection of diverse odorants and to improve the sensitivity of sensor devices.

  13. Parametric Investigations of Non-Conventional Hall Thruster

    SciTech Connect

    Raitses, Y.; Fisch, N.J.

    2001-01-12

    Hall thrusters might better scale to low power with non-conventional geometry. A 9 cm cylindrical, ceramic-channel, Hall thruster with a cusp-type magnetic field distribution has been investigated. It exhibits discharge characteristics similar to conventional coaxial Hall thrusters, but does not expose as much channel surface. Significantly, its operation is not accompanied by large amplitude discharge low frequency oscillations.

  14. Electronic structures of topological insulators with non-conventional terminations

    NASA Astrophysics Data System (ADS)

    Zhu, Xiegang; Zhang, Yun; Feng, Wei; Yuan, Bingkai; Lai, Xinchun

    Until now, most works on topological insulators focus on the natural cleaving surfaces, i.e., conventional terminations. However, researches on the non-conventional surfaces of TIs are hindered due to the difficulties in preparation of those surfaces and the existence of large number of dangling bonds on those surfaces. What is more, due to the complications in the surface lattice structures, DFT calculations on the non-conventional surfaces are not favorable. In this work, by adopting the tight binding method based Green's Function, we systematically studied the surface states of non-conventional terminations of topological insulator Bi2Te3 and Bi2Se3. By using MBE, we manage to prepare topological insulator Bi2Te3 thin films with fractional quintuple layer (FQL) termination. Scanning tunneling microscopy (STM) reveals that the as-grown Bi2Te3 thin films may not necessarily terminate at the Van der Waals gap between two adjacent quintuple layers. The electronic structures of the FQL surfaces are studied in combination with quasi-particle interference (QPI) by scanning tunneling spectroscopy (STS). Our results suggest that the topological nature of SSs be preserved on non-conventional terminations. The robustness of the topological SSs is also demonstrated. Work supported by Grants from NSFC11404298, CAEP2014B0302045.

  15. Short-term effects of endothelins on tyrosine hydroxylase activity and expression in the olfactory bulb of normotensive rats.

    PubMed

    Nabhen, Sabrina L; Perfume, Guadalupe; Battistone, María A; Rossi, Andrés; Abramoff, Tamara; Bianciotti, Liliana G; Vatta, Marcelo S

    2009-05-01

    The olfactory system in rats is part of the limbic region with extensive afferent connections with brain areas involved in the regulation of behaviour and autonomic responses. The existence of the endothelin system and catecholaminergic neurons in the olfactory bulb suggests that endothelins may modulate noradrenergic transmission and diverse olfactory mediated processes. In the present work we studied the effect of endothelin-1 and -3 on neuronal norepinephrine release and the short-term regulation of tyrosine hydroxylase in the olfactory bulb. Results showed that both endothelins increased tyrosine hydroxylase activity through the activation of a non-conventional endothelin G-protein coupled receptor, coupled to the stimulation of protein kinase A and C, as well as Ca(2+)/calmodulin-dependent protein kinase II. On the other hand, neither endothelin-1 nor endothelin-3 modified tyrosine hydroxylase total protein levels, but both peptides increased the phosphorylation of serine residues of the enzyme at sites 19 and 40. Furthermore, endothelins enhanced norepinephrine release in olfactory neurons suggesting that this event may contribute to increased tyrosine hydroxylase activity by reducing the feedback inhibition. Taken together present findings show a clear interaction between the endothelin system, and the catecholaminergic transmission in the olfactory bulb. Additional studies are required to evaluate the physiological functions regulated by endothelins at this brain level.

  16. Deep sequencing of the olfactory epithelium reveals specific chemosensory receptors are expressed at sexual maturity in the European eel Anguilla anguilla.

    PubMed

    Churcher, Allison M; Hubbard, Peter C; Marques, João Pedro; Canário, Adelino V M; Huertas, Mar

    2015-02-01

    Vertebrate genomes encode a diversity of G protein-coupled receptor (GPCR) that belong to large gene families and are used by olfactory systems to detect chemical cues found in the environment. It is not clear however, if individual receptors from these large gene families have evolved roles that are specific to certain life stages. Here, we used deep sequencing to identify differentially expressed receptor transcripts in the olfactory epithelia (OE) of freshwater, seawater and sexually mature male eels (Anguilla anguilla). This species is particularly intriguing because of its complex life cycle, extreme long-distance migrations and early-branching position within the teleost phylogeny. In the A. anguillaOE, we identified full-length transcripts for 13, 112, 6 and 38 trace amine-associated receptors, odorant receptors (OR) and type I and type II vomeronasal receptors (V1R and V2R). Most of these receptors were expressed at similar levels at different life stages and a subset of OR and V2R-like transcripts was more abundant in sexually mature males suggesting that ORs and V2R-like genes are important for reproduction. We also identified a set of GPCR signal transduction genes that were differentially expressed indicating that eels make use of different GPCR signal transduction genes at different life stages. The finding that a diversity of chemosensory receptors is expressed in the olfactory epithelium and that a subset is differentially expressed suggests that most receptors belonging to large chemosensory gene families have functions that are important at multiple life stages, while a subset has evolved specific functions at different life stages.

  17. Molecular Characterization and Differential Expression of an Olfactory Receptor Gene Family in the White-Backed Planthopper Sogatella furcifera Based on Transcriptome Analysis

    PubMed Central

    He, Ming; Zhang, Ya-Nan; He, Peng

    2015-01-01

    The white-backed planthopper, Sogatella furcifera, a notorious rice pest in Asia, employs host plant volatiles as cues for host location. In insects, odor detection is mediated by two types of olfactory receptors: odorant receptors (ORs) and ionotropic receptors (IRs). In this study, we identified 63 SfurORs and 14 SfurIRs in S. furcifera based on sequences obtained from the head transcriptome and bioinformatics analysis. The motif-pattern of 130 hemiptera ORs indicated an apparent differentiation in this order. Phylogenetic trees of the ORs and IRs were constructed using neighbor-joining estimates. Most of the ORs had orthologous genes, but a specific OR clade was identified in S. furcifera, which suggests that these ORs may have specific olfactory functions in this species. Our results provide a basis for further investigations of how S. furcifera coordinates its olfactory receptor genes with its plant hosts, thereby providing a foundation for novel pest management approaches based on these genes. PMID:26540266

  18. Aversive odorant causing appetite decrease downregulates tyrosine decarboxylase gene expression in the olfactory receptor neuron of the blowfly, Phormia regina

    NASA Astrophysics Data System (ADS)

    Ishida, Yuko; Ozaki, Mamiko

    2012-01-01

    In the blowfly Phormia regina, exposure to d-limonene for 5 days during feeding inhibits proboscis extension reflex behavior due to decreasing tyramine (TA) titer in the brain. TA is synthesized by tyrosine decarboxylase (Tdc) and catalyzed into octopamine (OA) by TA ß-hydroxylase (Tbh). To address the mechanisms of TA titer regulation in the blowfly, we cloned Tdc and Tbh cDNAs from P. regina (PregTdc and PregTbh). The deduced amino acid sequences of both proteins showed high identity to those of the corresponding proteins from Drosophila melanogaster at the amino acid level. PregTdc was expressed in the antenna, labellum, and tarsus whereas PregTbh was expressed in the head, indicating that TA is mainly synthesized in the sensory organs whereas OA is primarily synthesized in the brain. d-Limonene exposure significantly decreased PregTdc expression in the antenna but not in the labellum and the tarsus, indicating that PregTdc expressed in the antenna is responsible for decreasing TA titer. PregTdc-like immunoreactive material was localized in the thin-walled sensillum. In contrast, the OA/TA receptor (PregOAR/TAR) was localized to the thick-walled sensillum. The results indicated that d-limonene inhibits PregTdc expression in the olfactory receptor neurons in the thin-walled sensilla, likely resulting in reduced TA levels in the receptor neurons in the antenna. TA may be transferred from the receptor neuron to the specific synaptic junction in the antennal lobe of the brain through the projection neurons and play a role in conveying the aversive odorant information to the projection and local neurons.

  19. Smoke, pheromone and kairomone olfactory receptor neurons in males and females of the pine sawyer Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae).

    PubMed

    Álvarez, Gonzalo; Ammagarahalli, Byrappa; Hall, David R; Pajares, Juan A; Gemeno, César

    2015-11-01

    The response of antennal olfactory receptor neurons (ORNs) of Monochamus galloprovincialis to several odourants was tested using single sensillum electrophysiology. Behaviourally active pheromone, and kairomone (host and sympatric bark beetle pheromone) odours were tested alongside smoke compounds released by burnt wood that are potentially attractive to the insect. The antennae bore several types of sensilla. Two plate areas in the proximal and distal ends of each antennal segment were covered with basiconic sensilla that responded to the odour stimuli. Sensilla basiconica contained one or two cells of different spike amplitude. The 32 male and 38 female ORNs tested responded with excitations or inhibitions to the different plant odours. In general the response of male and female receptors was very similar so they were pooled to perform a cluster analysis on ORN responses. Six ORNs were clearly specialised for pheromone reception. Responses to kairomone and smoke odours were less specific than those of pheromone, but a group of 9 cells was clearly excited by smoke compounds (mainly eugenol and 4-methyl 2-methoxyphenol), a group of 8 cells was very responsive to α-pinene, β-pinene and cis-verbenol, and a group of 14 cells responded to a wider range of compounds. The rest of the cells (47%) were either non-responsive or slightly inhibited by smoke compounds. Dose-response curves were obtained for several compounds. Different compounds induced significantly different latencies and these appeared to be unrelated to their boiling point. PMID:26296453

  20. The C. elegans D2-Like Dopamine Receptor DOP-3 Decreases Behavioral Sensitivity to the Olfactory Stimulus 1-Octanol

    PubMed Central

    Ezak, Meredith J.; Ferkey, Denise M.

    2010-01-01

    We previously found that dopamine signaling modulates the sensitivity of wild-type C. elegans to the aversive odorant 1-octanol. C. elegans lacking the CAT-2 tyrosine hydroxylase enzyme, which is required for dopamine biosynthesis, are hypersensitive in their behavioral avoidance of dilute concentrations of octanol. Dopamine can also modulate the context-dependent response of C. elegans lacking RGS-3 function, a negative regulator of Gα signaling. rgs-3 mutant animals are defective in their avoidance of 100% octanol when they are assayed in the absence of food (E. coli bacterial lawn), but their response is restored when they are assayed in the presence of food or exogenous dopamine. However, it is not known which receptor might be mediating dopamine's effects on octanol avoidance. Herein we describe a role for the C. elegans D2-like receptor DOP-3 in the regulation of olfactory sensitivity. We show that DOP-3 is required for the ability of food and exogenous dopamine to rescue the octanol avoidance defect of rgs-3 mutant animals. In addition, otherwise wild-type animals lacking DOP-3 function are hypersensitive to dilute octanol, reminiscent of cat-2 mutants. Furthermore, we demonstrate that DOP-3 function in the ASH sensory neurons is sufficient to rescue the hypersensitivity of dop-3 mutant animals, while dop-3 RNAi knockdown in ASH results in octanol hypersensitivity. Taken together, our data suggest that dopaminergic signaling through DOP-3 normally acts to dampen ASH signaling and behavioral sensitivity to octanol. PMID:20209143

  1. Smoke, pheromone and kairomone olfactory receptor neurons in males and females of the pine sawyer Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae).

    PubMed

    Álvarez, Gonzalo; Ammagarahalli, Byrappa; Hall, David R; Pajares, Juan A; Gemeno, César

    2015-11-01

    The response of antennal olfactory receptor neurons (ORNs) of Monochamus galloprovincialis to several odourants was tested using single sensillum electrophysiology. Behaviourally active pheromone, and kairomone (host and sympatric bark beetle pheromone) odours were tested alongside smoke compounds released by burnt wood that are potentially attractive to the insect. The antennae bore several types of sensilla. Two plate areas in the proximal and distal ends of each antennal segment were covered with basiconic sensilla that responded to the odour stimuli. Sensilla basiconica contained one or two cells of different spike amplitude. The 32 male and 38 female ORNs tested responded with excitations or inhibitions to the different plant odours. In general the response of male and female receptors was very similar so they were pooled to perform a cluster analysis on ORN responses. Six ORNs were clearly specialised for pheromone reception. Responses to kairomone and smoke odours were less specific than those of pheromone, but a group of 9 cells was clearly excited by smoke compounds (mainly eugenol and 4-methyl 2-methoxyphenol), a group of 8 cells was very responsive to α-pinene, β-pinene and cis-verbenol, and a group of 14 cells responded to a wider range of compounds. The rest of the cells (47%) were either non-responsive or slightly inhibited by smoke compounds. Dose-response curves were obtained for several compounds. Different compounds induced significantly different latencies and these appeared to be unrelated to their boiling point.

  2. Topological change and impedance spectrum of rat olfactory receptor I7: A comparative analysis with bovine rhodopsin and bacteriorhodopsin

    NASA Astrophysics Data System (ADS)

    Alfinito, Eleonora; Pennetta, Cecilia; Reggiani, Lino

    2009-04-01

    We present a theoretical investigation on possible selection of olfactory receptors (ORs) as sensing components of nanobiosensors. Accordingly, we generate the impedance spectra of the rat OR I7 in the native and activated states and analyze their differences. In this way, we connect the protein morphological transformation, caused by the sensing action, with its change in electrical impedance. The results are compared with those obtained by studying the best known protein of the G protein coupled receptor (GPCR) family: bovine rhodopsin. Our investigations indicate that a change in morphology goes with a change in impedance spectrum mostly associated with a decrease in the static impedance up to about 60% of the initial value, in qualitative agreement with existing experiments on rat OR I7. The predictiveness of the model is tested successfully for the case of recent experiments on bacteriorhodopsin. The present results point to a promising development of a new class of nanobiosensors based on the electrical properties of GPCR and other sensing proteins.

  3. Non-conventional hydrogen bonds: pterins-metal anions.

    PubMed

    Vargas, Rubicelia; Martínez, Ana

    2011-07-28

    In this paper, we present an analysis of the interaction of metal ions (Cu, Ag and Au) with three different pterins (pterin, isoxanthopterin and sepiapterin) to provide insights concerning the formation of conventional and non-conventional H bonds. Density functional theory calculations were performed in order to reveal the optimized structures of pterin molecules, dimers and tetramers compounds, both with and without metal anions (M). The interaction with small metal clusters (M(3)) is also considered. The formation of different systems is characterized in terms of the structural parameters and hydrogen binding energies (HBE). The HBE values for pterin-M systems presented in this study lie between 22 and 60 kcal mol(-1) and can therefore be classified as strong conventional and strong non-conventional hydrogen bonds. The HBE with small metal clusters (pterin-M(3)) are smaller than the HBE with metal atoms. Vertical electron detachment energies (VEDEs) are also reported in order to analyze the influence of the hydrogen bond on electronic properties. A direct correlation between VEDEs and HBE was found for pterin-M and pterin-M(3) complexes; i.e. as the VEDEs increase, the HBE also augment. The only exception is with Ag(3). The main conclusion derived from this study is that the strong non-conventional hydrogen bonds formed between pterins, dimers and tetramers do not affect the formation of conventional hydrogen bonds between pterins but they do influence the VEDEs. PMID:21695329

  4. Advances in Gene Expression in Non-Conventional Yeasts

    NASA Astrophysics Data System (ADS)

    Nel, Sanet; Labuschagne, Michel; Albertyn, Jacobus

    Yeast has been a favoured lower eukaryotic system for the expression and production of recombinant proteins for both basic research and practical applications, and the demand for foreign-gene expression systems is increasing rapidly. Despite the vast amount of information on the molecular biology and physiology of Saccharomyces cerevisiae, which has consequently been the first choice as host system for recombinant protein production in the past, several limitations have been identified in this expression system. These limitations have recently been relieved by the development of expression systems in other yeast species known as ‘ non-conventional yeasts’ or ‘non-Saccharomyces ’ yeasts. With the increasing interest in the biotechnological applications of these yeasts in applied and fundamental studies and processes, the term ‘ non-conventional ’ yeast may well soon become redundant. As there is no universal expression system for heterologous protein production, it is necessary to recognize the merits and demerits of each system in order to make a right choice. This chapter will evaluate the competitive environment of non-conventional expression platforms represented by some of the best-known alternative yeasts systems including Kluyveromyces lactis, Yarrowia lipolytica, Hansenula polymorpha, Pichia pastoris and more recently, Arxula adeninivorans.

  5. A characterization of the Manduca sexta serotonin receptors in the context of olfactory neuromodulation.

    PubMed

    Dacks, Andrew M; Reale, Vincenzina; Pi, Yeli; Zhang, Wujie; Dacks, Joel B; Nighorn, Alan J; Evans, Peter D

    2013-01-01

    Neuromodulation, the alteration of individual neuron response properties, has dramatic consequences for neural network function and is a phenomenon observed across all brain regions and taxa. However, the mechanisms underlying neuromodulation are made complex by the diversity of neuromodulatory receptors expressed within a neural network. In this study we begin to examine the receptor basis for serotonergic neuromodulation in the antennal lobe of Manduca sexta. To this end we cloned all four known insect serotonin receptor types from Manduca (the Ms5HTRs). We used phylogenetic analyses to classify the Ms5HTRs and to establish their relationships to other insect serotonin receptors, other insect amine receptors and the vertebrate serotonin receptors. Pharmacological assays demonstrated that each Ms5HTR was selective for serotonin over other endogenous amines and that serotonin had a similar potency at all four Ms5HTRs. The pharmacological assays also identified several agonists and antagonists of the different Ms5HTRs. Finally, we found that the Ms5HT1A receptor was expressed in a subpopulation of GABAergic local interneurons suggesting that the Ms5HTRs are likely expressed heterogeneously within the antennal lobe based on functional neuronal subtype. PMID:23922709

  6. Transient reversal of olfactory preference following castration in male rats: Implication for estrogen receptor involvement.

    PubMed

    Xiao, Kai; Chiba, Atsuhiko; Sakuma, Yasuo; Kondo, Yasuhiko

    2015-12-01

    We examined the effects of the sex steroid milieu on sexual odor preference of sexually-experienced male rats using an alternate choice paradigm after endocrine manipulations. Gonadally intact (GI) males showed a male typical preference, i.e. spent longer time sniffing estrous females than males or ovariectomized females. At 1-2 weeks after orchidectomy (ORx), the males exhibited a transient preference for sexually vigorous males, a female typical preference pattern, followed by a total loss of preference after 4 weeks. Subcutaneous implantation of a Silastic capsule containing formestane (4-OHA), an aromatase inhibitor, had no effect on the preference of gonadally intact rats, but successfully prevented the emergence of the female typical preference after ORx. Capsules containing testosterone (T), dihydrotestosterone (DHT), or estradiol benzoate (EB), but not those with cholesterol (CH), restored masculine typical preference in ORx males at 2 weeks after the placement. The feminine preference for males was observed at 2-3 weeks after removal of T or EB capsules, but not by the removal of DHT and CH capsules. The results suggest that either exogenous androgen or estrogen maintains the masculine typical odor preference. Estrogen itself or produced through aromatization of circulating T, induces a transient feminine typical preference at a certain decreased titer during its disappearance from the circulation. Estrogen at different titers might determine appearance of masculine or feminine typical olfactory preference in adult ORx rats.

  7. Potential ligand-binding residues in rat olfactory receptors identified by correlated mutation analysis

    NASA Technical Reports Server (NTRS)

    Singer, M. S.; Oliveira, L.; Vriend, G.; Shepherd, G. M.

    1995-01-01

    A family of G-protein-coupled receptors is believed to mediate the recognition of odor molecules. In order to identify potential ligand-binding residues, we have applied correlated mutation analysis to receptor sequences from the rat. This method identifies pairs of sequence positions where residues remain conserved or mutate in tandem, thereby suggesting structural or functional importance. The analysis supported molecular modeling studies in suggesting several residues in positions that were consistent with ligand-binding function. Two of these positions, dominated by histidine residues, may play important roles in ligand binding and could confer broad specificity to mammalian odor receptors. The presence of positive (overdominant) selection at some of the identified positions provides additional evidence for roles in ligand binding. Higher-order groups of correlated residues were also observed. Each group may interact with an individual ligand determinant, and combinations of these groups may provide a multi-dimensional mechanism for receptor diversity.

  8. Increased migration of olfactory ensheathing cells secreting the Nogo receptor ectodomain over inhibitory substrates and lesioned spinal cord.

    PubMed

    Reginensi, Diego; Carulla, Patricia; Nocentini, Sara; Seira, Oscar; Serra-Picamal, Xavier; Torres-Espín, Abel; Matamoros-Angles, Andreu; Gavín, Rosalina; Moreno-Flores, María Teresa; Wandosell, Francisco; Samitier, Josep; Trepat, Xavier; Navarro, Xavier; del Río, José Antonio

    2015-07-01

    Olfactory ensheathing cell (OEC) transplantation emerged some years ago as a promising therapeutic strategy to repair injured spinal cord. However, inhibitory molecules are present for long periods of time in lesioned spinal cord, inhibiting both OEC migration and axonal regrowth. Two families of these molecules, chondroitin sulphate proteoglycans (CSPG) and myelin-derived inhibitors (MAIs), are able to trigger inhibitory responses in lesioned axons. Mounting evidence suggests that OEC migration is inhibited by myelin. Here we demonstrate that OEC migration is largely inhibited by CSPGs and that inhibition can be overcome by the bacterial enzyme Chondroitinase ABC. In parallel, we have generated a stable OEC cell line overexpressing the Nogo receptor (NgR) ectodomain to reduce MAI-associated inhibition in vitro and in vivo. Results indicate that engineered cells migrate longer distances than unmodified OECs over myelin or oligodendrocyte-myelin glycoprotein (OMgp)-coated substrates. In addition, they also show improved migration in lesioned spinal cord. Our results provide new insights toward the improvement of the mechanisms of action and optimization of OEC-based cell therapy for spinal cord lesion.

  9. Unravelling the Complexity of Human Olfactory Receptor Repertoire by Copy Number Analysis across Population Using High Resolution Arrays

    PubMed Central

    Veerappa, Avinash M.; Vishweswaraiah, Sangeetha; Lingaiah, Kusuma; Murthy, Megha; Manjegowda, Dinesh S.; Nayaka, Radhika; Ramachandra, Nallur B.

    2013-01-01

    Olfactory receptors (OR), responsible for detection of odor molecules, belong to the largest family of genes and are highly polymorphic in nature having distinct polymorphisms associated with specific regions around the globe. Since there are no reports on the presence of copy number variations in OR repertoire of Indian population, the present investigation in 43 Indians along with 270 HapMap and 31 Tibetan samples was undertaken to study genome variability and evolution. Analysis was performed using Affymetrix Genome-Wide Human SNP Array 6.0 chip, Affymterix CytoScan® High-Density array, HD-CNV, and MAFFT program. We observed a total of 1527 OR genes in 503 CNV events from 81.3% of the study group, which includes 67.6% duplications and 32.4% deletions encompassing more of genes than pseudogenes. We report human genotypic variation in functional OR repertoire size across populations and it was found that the combinatorial effect of both “orthologous obtained from closely related species” and “paralogous derived sequences” provide the complexity to the continuously occurring OR CNVs. PMID:23843967

  10. The olfactory receptor gene repertoires in secondary-adapted marine vertebrates: evidence for reduction of the functional proportions in cetaceans.

    PubMed

    Kishida, Takushi; Kubota, Shin; Shirayama, Yoshihisa; Fukami, Hironobu

    2007-08-22

    An olfactory receptor (OR) multigene family is responsible for the well-developed sense of smell possessed by terrestrial tetrapods. Mammalian OR genes had diverged greatly in the terrestrial environment after the fish-tetrapod split, indicating their importance to land habitation. In this study, we analysed OR genes of marine tetrapods (minke whale Balaenoptera acutorostrata, dwarf sperm whale Kogia sima, Dall's porpoise Phocoenoides dalli, Steller's sea lion Eumetopias jubatus and loggerhead sea turtle Caretta caretta) and revealed that the pseudogene proportions of OR gene repertoires in whales were significantly higher than those in their terrestrial relative cattle and also in sea lion and sea turtle. On the other hand, the pseudogene proportion of OR sequences in sea lion was not significantly higher compared with that in their terrestrial relative (dog). It indicates that secondary perfectly adapted marine vertebrates (cetaceans) have lost large amount of their OR genes, whereas secondary-semi-adapted marine vertebrates (sea lions and sea turtles) still have maintained their OR genes, reflecting the importance of terrestrial environment for these animals. PMID:17535789

  11. Phosphoinositide-3-Kinase Is the Primary Mediator of Phosphoinositide-Dependent Inhibition in Mammalian Olfactory Receptor Neurons.

    PubMed

    Ukhanov, Kirill; Corey, Elizabeth; Ache, Barry W

    2016-01-01

    Odorants inhibit as well as excite primary olfactory receptor neurons (ORNs) in many animal species. Growing evidence suggests that inhibition of mammalian ORNs is mediated by phosphoinositide (PI) signaling through activation of phosphoinositide 3-kinase (PI3K), and that canonical adenylyl cyclase III signaling and PI3K signaling interact to provide the basis for ligand-induced selective signaling. As PI3K is known to act in concert with phospholipase C (PLC) in some cellular systems, the question arises as to whether they work together to mediate inhibitory transduction in mammalian ORNs. The present study is designed to test this hypothesis. While we establish that multiple PLC isoforms are expressed in the transduction zone of rat ORNs, that odorants can activate PLC in ORNs in situ, and that pharmacological blockade of PLC enhances the excitatory response to an odorant mixture in some ORNs in conjunction with PI3K blockade, we find that by itself PLC does not account for an inhibitory response. We conclude that PLC does not make a measurable independent contribution to odor-evoked inhibition, and that PI3K is the primary mediator of PI-dependent inhibition in mammalian ORNs.

  12. Phosphoinositide-3-Kinase Is the Primary Mediator of Phosphoinositide-Dependent Inhibition in Mammalian Olfactory Receptor Neurons

    PubMed Central

    Ukhanov, Kirill; Corey, Elizabeth; Ache, Barry W.

    2016-01-01

    Odorants inhibit as well as excite primary olfactory receptor neurons (ORNs) in many animal species. Growing evidence suggests that inhibition of mammalian ORNs is mediated by phosphoinositide (PI) signaling through activation of phosphoinositide 3-kinase (PI3K), and that canonical adenylyl cyclase III signaling and PI3K signaling interact to provide the basis for ligand-induced selective signaling. As PI3K is known to act in concert with phospholipase C (PLC) in some cellular systems, the question arises as to whether they work together to mediate inhibitory transduction in mammalian ORNs. The present study is designed to test this hypothesis. While we establish that multiple PLC isoforms are expressed in the transduction zone of rat ORNs, that odorants can activate PLC in ORNs in situ, and that pharmacological blockade of PLC enhances the excitatory response to an odorant mixture in some ORNs in conjunction with PI3K blockade, we find that by itself PLC does not account for an inhibitory response. We conclude that PLC does not make a measurable independent contribution to odor-evoked inhibition, and that PI3K is the primary mediator of PI-dependent inhibition in mammalian ORNs. PMID:27147969

  13. Phosphoinositide-3-Kinase Is the Primary Mediator of Phosphoinositide-Dependent Inhibition in Mammalian Olfactory Receptor Neurons.

    PubMed

    Ukhanov, Kirill; Corey, Elizabeth; Ache, Barry W

    2016-01-01

    Odorants inhibit as well as excite primary olfactory receptor neurons (ORNs) in many animal species. Growing evidence suggests that inhibition of mammalian ORNs is mediated by phosphoinositide (PI) signaling through activation of phosphoinositide 3-kinase (PI3K), and that canonical adenylyl cyclase III signaling and PI3K signaling interact to provide the basis for ligand-induced selective signaling. As PI3K is known to act in concert with phospholipase C (PLC) in some cellular systems, the question arises as to whether they work together to mediate inhibitory transduction in mammalian ORNs. The present study is designed to test this hypothesis. While we establish that multiple PLC isoforms are expressed in the transduction zone of rat ORNs, that odorants can activate PLC in ORNs in situ, and that pharmacological blockade of PLC enhances the excitatory response to an odorant mixture in some ORNs in conjunction with PI3K blockade, we find that by itself PLC does not account for an inhibitory response. We conclude that PLC does not make a measurable independent contribution to odor-evoked inhibition, and that PI3K is the primary mediator of PI-dependent inhibition in mammalian ORNs. PMID:27147969

  14. Phosphoinositide 3-kinase dependent inhibition as a broad basis for opponent coding in Mammalian olfactory receptor neurons.

    PubMed

    Ukhanov, Kirill; Corey, Elizabeth A; Ache, Barry W

    2013-01-01

    Phosphoinositide 3-kinase (PI3K) signaling has been implicated in mediating inhibitory odorant input to mammalian olfactory receptor neurons (ORNs). To better understand the breadth of such inhibition in odor coding, we screened a panel of odorants representing different chemical classes, as well as odorants known to occur in a natural odor object (tomato), for their ability to rapidly activate PI3K-dependent inhibitory signaling. Odorants were screened on dissociated native rat ORNs before and after pre-incubation with the PI3K-isoform specific blockers AS252424 and TGX221. Many different odorants increased their excitatory strength for particular ORNs following PI3K blockade in a manner consistent with activating PI3K-dependent inhibitory signaling in those cells. The PI3K-dependent inhibitory odorants overlapped with conventional excitatory odorants, but did not share the same bias, indicating partial partitioning of the odor space. Finding that PI3K-dependent inhibition can be activated by a wide range of otherwise conventional excitatory odorants strongly implies PI3K-dependent inhibition provides a broad basis for opponent coding in mammalian ORNs. PMID:23585911

  15. ORA1, a Zebrafish Olfactory Receptor Ancestral to All Mammalian V1R Genes, Recognizes 4-Hydroxyphenylacetic Acid, a Putative Reproductive Pheromone

    PubMed Central

    Behrens, Maik; Frank, Oliver; Rawel, Harshadrai; Ahuja, Gaurav; Potting, Christoph; Hofmann, Thomas; Meyerhof, Wolfgang; Korsching, Sigrun

    2014-01-01

    The teleost v1r-related ora genes are a small, highly conserved olfactory receptor gene family of only six genes, whose direct orthologues can be identified in lineages as far as that of cartilaginous fish. However, no ligands for fish olfactory receptor class A related genes (ORA) had been uncovered so far. Here we have deorphanized the ORA1 receptor using heterologous expression and calcium imaging. We report that zebrafish ORA1 recognizes with high specificity and sensitivity 4-hydroxyphenylacetic acid. The carboxyl group of this compound is required in a particular distance from the aromatic ring, whereas the hydroxyl group in the para-position is not essential, but strongly enhances the binding efficacy. Low concentrations of 4-hydroxyphenylacetic acid elicit increases in oviposition frequency in zebrafish mating pairs. This effect is abolished by naris closure. We hypothesize that 4-hydroxyphenylacetic acid might function as a pheromone for reproductive behavior in zebrafish. ORA1 is ancestral to mammalian V1Rs, and its putative function as pheromone receptor is reminiscent of the role of several mammalian V1Rs as pheromone receptors. PMID:24831010

  16. Velocity Map Imaging Studies of Non-Conventional Methanethiol Photochemistry

    NASA Astrophysics Data System (ADS)

    Toulson, Benjamin W.; Alaniz, Jonathan; Murray, Craig

    2014-06-01

    Velocity map imaging (VMI) in combination with state-selective resonance enhanced multiphoton ionization (REMPI) has been used to study the photodissociation dynamics of methanethiol following excitation to the first and second singlet electronically excited states. Formation of sulfur atoms, in both the singlet and triplet manifolds, is observed and can be attributed to primary dissociation of the parent molecule. We will report the nascent photofragment velocity distributions, and hence the internal energy of the methane co-fragment. Sulfur atom quantum yields are benchmarked against a known standard to evaluate the significance of this pathway. The role of non-conventional photochemical mechanisms such as roaming-mediated intersystem crossing, previously observed in methylamine photochemistry, will be discussed. James O. Thomas, Katherine E. Lower, and Craig Murray, The Journal of Physical Chemistry Letters, 2012, 3 (10), 1341-1345.

  17. A use-dependent sodium current modification induced by type I pyrethroid insecticides in honeybee antennal olfactory receptor neurons.

    PubMed

    Kadala, Aklesso; Charreton, Mercedes; Jakob, Ingrid; Le Conte, Yves; Collet, Claude

    2011-06-01

    We studied the mode of action of type I pyrethroids on the voltage-dependent sodium current from honeybee olfactory receptor neurons (ORNs), whose proper function in antenna is crucial for interindividual communication in this species. Under voltage-clamp, tetramethrin and permethrin induce a long lasting TTX-sensitive tail current upon repolarization, which is the hallmark of an abnormal prolongation of the open channel configuration. Permethrin and tetramethrin also slow down the sodium current fast inactivation. Tetramethrin and permethrin both bind to the closed state of the channel as suggested by the presence of an obvious tail current after the first single depolarization applied in the presence of either compounds. Moreover, at first sight, channel opening seems to promote tetramethrin and permethrin binding as evidenced by the progressive tail current summation along with trains of stimulations, tetramethrin being more potent at modifying channels than permethrin. However, a use-dependent increase in the sodium peak current along with stimulations suggests that the tail current accumulation could also be a consequence of progressively unmasked silent channels. Experiments with the sea anemone toxin ATX-II that suppresses sodium channels fast inactivation are consistent with the hypothesis that these silent channels are either in an inactivated state at rest, or that they normally inactivate before they open so that they do not participate to the control sodium current. In honeybee ORNs, three processes lead to a use-dependent pyrethroid-induced tail current accumulation: (i) a recruitment of silent channels that produces an increase in the peak sodium current, (ii) a slowing down of the sodium current inactivation produced by prolongation of channels opening and (iii) a typical deceleration in current deactivation. The use-dependent recruitment of silent sodium channels in honeybee ORNs makes pyrethroids more potent at modifying neuronal excitability.

  18. Immunization Against Specific Fragments of Neurotrophin p75 Receptor Protects Forebrain Cholinergic Neurons in the Olfactory Bulbectomized Mice

    PubMed Central

    Bobkova, Natalia; Vorobyov, Vasily; Medvinskaya, Natalia; Nesterova, Inna; Tatarnikova, Olga; Nekrasov, Pavel; Samokhin, Alexander; Deev, Alexander; Sengpiel, Frank; Koroev, Dmitry; Volpina, Olga

    2016-01-01

    Alzheimer’s disease (AD) is characterized by progressive cognitive impairment associated with marked cholinergic neuron loss and amyloid-β (Aβ) peptide accumulation in the brain. The cytotoxicity in AD is mediated, at least in part, by Aβ binding with the extracellular domain of the p75 neurotrophin receptor (p75NTR), localized predominantly in the membranes of acetylcholine-producing neurons in the basal forebrain. Hypothesizing that an open unstructured loop of p75NTR might be the effective site for Aβ binding, we have immunized both olfactory bulbectomized (OBX) and sham-operated (SO) mice (n = 82 and 49, respectively) with synthetic peptides, structurally similar to different parts of the loops, aiming to block them by specific antibodies. OBX-mice have been shown in previous studies, and confirmed in the present one, to be characterized by typical behavioral, morphological, and biochemical AD hallmarks, including cholinergic deficits in forebrain neurons. Immunization of OBX- or SO-mice with KLH conjugated fragments of p75NTR induced high titers of specific serum antibodies for each of nine chosen fragments. However, maximal protective effects on spatial memory, evaluated in a Morris water maze, and on activity of choline acetyltransferase in forebrain neurons, detected by immunoreactivity to specific antibodies, were revealed only for peptides with amino acid residue sequences of 155–164 and 167–176. We conclude that the approach based on immunological blockade of specific p75NTR sites, linked with the cytotoxicity, is a useful and effective tool for study of AD-associated mechanisms and for development of highly selective therapy of cholinergic malfunctioning in AD patients. PMID:27163825

  19. Deorphanization and characterization of the ectopically expressed olfactory receptor OR51B5 in myelogenous leukemia cells

    PubMed Central

    Manteniotis, S; Wojcik, S; Göthert, J R; Dürig, J; Dührsen, U; Gisselmann, G; Hatt, H

    2016-01-01

    The ectopic expression of olfactory receptors (ORs) in the human body has been of major interest in the past decade. Several studies have reported the expression of ORs not only in healthy tissues such as heart, sperm or skin cells, but also in cancerous tissues of the liver, prostate or intestine. In the present study, we detected the expression of OR51B5 in the chronic myelogenous leukemia (CML) cell line K562 and in white blood cell samples of clinically diagnosed acute myelogenous leukemia (AML) patients by reverse transcription-PCR and immunocytochemical staining. The known OR51B5 ligand isononyl alcohol increased the levels of intracellular Ca2+ in both AML patient blood cells and K562 cells. With calcium imaging experiments, we characterized in greater detail the OR51B5-mediated signaling pathway. Here, we observed an involvement of adenylate cyclase and the downstream L-type and T-type calcium channels. In addition, the activation of OR51B5 leads to an inhibition of cell proliferation in K562 cells. In western blot experiments, we found that incubation with isononyl alcohol led to a reduction in p38-MAPK (mitogen-activated protein kinase) phosphorylation that might be responsible for the decreased cell proliferation. In the present study, we characterized the OR51B5-mediated signaling pathway downstream of the activation with isononyl alcohol, which leads to reduced proliferation and therefore provide a novel pharmacological target for CML and AML, the latter of which remains difficult to treat. PMID:27551504

  20. Silencing the Olfactory Co-Receptor RferOrco Reduces the Response to Pheromones in the Red Palm Weevil, Rhynchophorus ferrugineus.

    PubMed

    Soffan, Alan; Antony, Binu; Abdelazim, Mahmoud; Shukla, Paraj; Witjaksono, Witjaksono; Aldosari, Saleh A; Aldawood, Abdulrahman S

    2016-01-01

    The red palm weevil (RPW, Rhynchophorus ferrugineus), one of the most widespread of all invasive insect pest species, is a major cause of severe damage to economically important palm trees. RPW exhibits behaviors very similar to those of its sympatric species, the Asian palm weevil (R. vulneratus), which is restricted geographically to the southern part of Southeast Asia. Although efficient and sustainable control of these pests remains challenging, olfactory-system disruption has been proposed as a promising approach for controlling palm weevils. Here, we report the cloning and sequencing of an olfactory co-receptor (Orco) from R. ferrugineus (RferOrco) and R. vulneratus (RvulOrco) and examine the effects of RferOrco silencing (RNAi) on odorant detection. RferOrco and RvulOrco encoding 482 amino acids showing 99.58% identity. The injection of double-stranded RNA (dsRNA) from RferOrco into R. ferrugineus pupae significantly reduced RferOrco gene expression and led to the failure of odor-stimulus detection, as confirmed through olfactometer and electroantennography (EAG) assays. These results suggest that olfactory-system disruption leading to reduced pheromone detection holds great potential for RPW pest-control strategies. PMID:27606688

  1. Silencing the Olfactory Co-Receptor RferOrco Reduces the Response to Pheromones in the Red Palm Weevil, Rhynchophorus ferrugineus

    PubMed Central

    Soffan, Alan; Abdelazim, Mahmoud; Shukla, Paraj; Witjaksono, Witjaksono; Aldosari, Saleh A.; Aldawood, Abdulrahman S.

    2016-01-01

    The red palm weevil (RPW, Rhynchophorus ferrugineus), one of the most widespread of all invasive insect pest species, is a major cause of severe damage to economically important palm trees. RPW exhibits behaviors very similar to those of its sympatric species, the Asian palm weevil (R. vulneratus), which is restricted geographically to the southern part of Southeast Asia. Although efficient and sustainable control of these pests remains challenging, olfactory-system disruption has been proposed as a promising approach for controlling palm weevils. Here, we report the cloning and sequencing of an olfactory co-receptor (Orco) from R. ferrugineus (RferOrco) and R. vulneratus (RvulOrco) and examine the effects of RferOrco silencing (RNAi) on odorant detection. RferOrco and RvulOrco encoding 482 amino acids showing 99.58% identity. The injection of double-stranded RNA (dsRNA) from RferOrco into R. ferrugineus pupae significantly reduced RferOrco gene expression and led to the failure of odor-stimulus detection, as confirmed through olfactometer and electroantennography (EAG) assays. These results suggest that olfactory-system disruption leading to reduced pheromone detection holds great potential for RPW pest-control strategies. PMID:27606688

  2. Olfactory receptors for a smell sensor: a comparative study of the electrical responses of rat I7 and human 17-40

    NASA Astrophysics Data System (ADS)

    Alfinito, E.; Millithaler, J.-F.; Reggiani, L.

    2011-12-01

    In this paper, we explore the relevant electrical properties of two olfactory receptors (ORs), one from rat, OR I7, and the other from human, OR 17-40, which are of interest for the realization of smell nanobiosensors. The investigation compares existing experiments, coming from electrochemical impedance spectroscopy, with the theoretical expectations obtained from an impedance network protein analogue, recently developed. The changes in the response due to the sensing action of the proteins are correlated with the conformational change undergone by the single protein. The satisfactory agreement between theory and experiments points to a promising development of a new class of nanobiosensors based on the electrical properties of sensing proteins.

  3. Histamine H₃ receptors modulate depolarization-evoked [³H]-noradrenaline release from rat olfactory bulb slices.

    PubMed

    Aquino-Miranda, Guillermo; Osorio-Espinoza, Angélica; Escamilla-Sánchez, Juan; González-Pantoja, Raúl; Ortiz, Jordi; Arias-Montaño, José-Antonio

    2012-02-01

    We have studied the effect of histamine H(3) receptor (H(3)R) activation on the depolarization-evoked release of labeled neurotransmitters from slices of the rat olfactory bulb (rOB). The presence of pre-synaptic H(3)Rs was evidenced by the specific binding of the H(3)R ligand N-α-[methyl-(3)H]histamine to membranes from rOB synaptosomes (maximum binding, B(max), 106 ± 19 fmol/mg protein; dissociation constant, K(d), 0.68 ± 0.11 nM) which was inhibited by selective H(3)R ligands (immepip, (R)(-)-α-methylhistamine (RAMH) and clobenpropit) with affinities similar to those previously reported for H(3)Rs expressed in other rat brain areas. Perfusion of rOB slices with the selective H(3)R agonist RAMH (0.1 and 1 μM) had no effect on the release of [(3)H]-γ-aminobutyric acid ([(3)H]-GABA), [(3)H]-d-aspartate, [(3)H]-dopamine or [(3)H]-5-hydroxytryptamine ([(3)H]-5-HT) evoked by depolarization with high K(+) (20 or 40 mM). [(3)H]-Noradrenaline release induced by 20 mM K(+) was reduced in a modest but significant manner by RAMH (94.9 ± 1.7% and 83.1 ± 2.1% of control release at 0.1 and 1 μM, respectively). The effect of 1 μM RAMH was blocked by the selective H(3)R antagonist/inverse agonist clobenpropit (5 μM). When tested alone clobenpropit and a second H(3)R antagonist/inverse agonist, ciproxifan (both at 1 μM) significantly increased K(+)-evoked [(3)H]-noradrenaline release to 119.4 ± 4.2% and 120.0 ± 3.7% of K(+) alone, respectively. Ciproxifan (1 μM) had no effect on the depolarization-evoked release of the other labeled neurotransmitters. These data indicate that H(3)Rs with constitutive activity modulate noradrenaline release in rOB, presumably through a pre-synaptic action. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

  4. The Olfactory Co-receptor Orco from the Migratory Locust (Locusta migratoria) and the Desert Locust (Schistocerca gregaria): Identification and Expression pattern

    PubMed Central

    Yang, Ying; Krieger, Jürgen; Zhang, Long; Breer, Heinz

    2012-01-01

    In locusts, olfaction plays a crucial role for initiating and controlling behaviours, including food seeking and aggregation with conspecifics, which underlie the agricultural pest capacity of the animals. In this context, the molecular basis of olfaction in these insects is of particular interest. Here, we have identified genes of two orthopteran species, Locusta migratoria and Schistocera gregaria, which encode the olfactory receptor co-receptor (Orco). It was found that the sequences of LmigOrco and SgreOrco share a high degree of identity to each other and also to Orco proteins from different insect orders. The Orco-expressing cells in the antenna of S. gregaria and L. migratoria were visualized by in situ hybridization. Orco expression could be assigned to clusters of cells in sensilla basiconica and few cells in sensilla trichodea, most likely representing olfactory sensory neurons. No Orco-positive cells were detected in sensilla coeloconica and sensilla chaetica. Orco expression was found already in all nymphal stages and was verified in some other tissues which are equipped with chemosensory hairs (mouthparts, tarsi, wings). Together, the results support the notion for a decisive role of Orco in locust olfaction. PMID:22211114

  5. Regenerative thermal oxidation for non-conventional applications

    SciTech Connect

    Gosselin, G.; Gravel, J.J.O.

    1999-07-01

    Regenerative Thermal Oxidation has been applied by Biothermica to treat non-conventional emissions. These emissions include pollutants as VOC, COC, TRS, PAH, PCB, HCl and odors. In the kraft pulping industry, environmental requirements for reduced emissions of total reduced sulfur (TRS) and volatile organic compounds (VOC) from pulping operations are leading to incinerators of high destruction efficiency and thermal performance. The first installation in Canada of a Regenerative Thermal Oxidation (RTO) was placed in service early in 1997 at a kraft pulp mill in the province of Quebec. Tests have shown a TRS reduction of 99.6% with a thermal efficiency of 88.5% in the RTO. It can be considered the best method to comply with the new norms for TRS atmospheric emissions in the pulp and paper industry. In the primary aluminum process, a marked improvement in anode properties can be gained by preparing the paste at high temperature, followed by cooling with a water addition in an intensive mixer. However, the addition of cooling water results in a large increase in the emissions of VOC and PAH which can prejudice the process. A number of emission control processes were evaluated. An improved Regenerative Thermal Oxidation (RTO) unit was installed in a modern aluminum plant in Canada. The emissions of VOCs and PAHs from an EIRICH intensive mixer-cooler were reduced by more than 99.9% while all troublesome deposits in the fumes collection system were eliminated. This enabled the plant to remain well within the emission levels allowed by the environmental authority while enjoying considerable benefits from improved anode qualities. In the asphalt roofing industry, RTO was applied to treat the VOC and COC emissions and several units have been in operation since 1990. In the United States two units were installed in asphalt shingle plants and new features in the process show a VOC and COC reduction of 99%.

  6. Expression of transient receptor potential channel vanilloid (TRPV) 1–4, melastin (TRPM) 5 and 8, and ankyrin (TRPA1) in the normal and methimazole-treated mouse olfactory epithelium

    PubMed Central

    Nakashimo, Yousuke; Takumida, Masaya; Fukuiri, Takashi; Anniko, Matti; Hirakawa, Katsuhiro

    2010-01-01

    Conclusion: It is suggested that TRPV1, 2, 3, and 4, TRPM5 and 8, and TRPA1 may play several roles in the olfactory epithelium (OE), contributing to olfactory chemosensation, olfactory adaptation, olfactory-trigeminal interaction, and OE fluid homeostasis. In patients with olfactory disturbance, TRPV1 and TRPM8 may be closely related to a high rate of recognition of curry and menthol odors, while TRPV2 may also play a crucial role in the regeneration of olfactory receptor neurons. Objective: Expression of TRPV1–4, TRPM5 and 8, and TRPA1 in the normal and methimazole-treated mouse OE was analyzed. Methods: The localization of TRPV1–4, TRPM5 and 8, and TRPA1 in the OE of normal and methimazole-treated CBA/J mice was investigated by immunohistochemistry. Results: Normal OE showed a positive immunofluorescent reaction to TRPV1–4, TRPM5 and 8, and TRPA1. In lamina propria, the nerve fibers displayed TRPV 1, 2, and 3, TRPM8 and TRPA1. In the pathological condition, the expression of TRPV3, TRPV4, TRPM5, and TRPA1 was markedly reduced and took a long time to recover. In contrast, expression of TRPM8 was scarcely affected, even in the pathological condition, while TRPV1 and TRPV2 showed early recovery following methimazole treatment. PMID:20586674

  7. Enhanced self-administration of the CB1 receptor agonist WIN55,212-2 in olfactory bulbectomized rats: evaluation of possible serotonergic and dopaminergic underlying mechanisms

    PubMed Central

    Amchova, Petra; Kucerova, Jana; Giugliano, Valentina; Babinska, Zuzana; Zanda, Mary T.; Scherma, Maria; Dusek, Ladislav; Fadda, Paola; Micale, Vincenzo; Sulcova, Alexandra; Fratta, Walter; Fattore, Liana

    2013-01-01

    Depression has been associated with drug consumption, including heavy or problematic cannabis use. According to an animal model of depression and substance use disorder comorbidity, we combined the olfactory bulbectomy (OBX) model of depression with intravenous drug self-administration procedure to verify whether depressive-like rats displayed altered voluntary intake of the CB1 receptor agonist WIN55,212-2 (WIN, 12.5 μg/kg/infusion). To this aim, olfactory-bulbectomized (OBX) and sham-operated (SHAM) Lister Hooded rats were allowed to self-administer WIN by lever-pressing under a continuous [fixed ratio 1 (FR-1)] schedule of reinforcement in 2 h daily sessions. Data showed that both OBX and SHAM rats developed stable WIN intake; yet, responses in OBX were constantly higher than in SHAM rats soon after the first week of training. In addition, OBX rats took significantly longer to extinguish the drug-seeking behavior after vehicle substitution. Acute pre-treatment with serotonin 5HT1B receptor agonist, CGS-12066B (2.5–10 mg/kg), did not significantly modify WIN intake in OBX and SHAM Lister Hooded rats. Furthermore, acute pre-treatment with CGS-12066B (10 and 15 mg/kg) did not alter responses in parallel groups of OBX and SHAM Sprague Dawley rats self-administering methamphetamine under higher (FR-2) reinforcement schedule with nose-poking as operandum. Finally, dopamine levels in the nucleus accumbens (NAc) of OBX rats did not increase in response to a WIN challenge, as in SHAM rats, indicating a dopaminergic dysfunction in bulbectomized rats. Altogether, our findings suggest that a depressive-like state may alter cannabinoid CB1 receptor agonist-induced brain reward function and that a dopaminergic rather than a 5-HT1B mechanism is likely to underlie enhanced WIN self-administration in OBX rats. PMID:24688470

  8. Variant Ionotropic Receptors Are Expressed in Olfactory Sensory Neurons of Coeloconic Sensilla on the Antenna of the Desert Locust (Schistocerca gregaria)

    PubMed Central

    Guo, Mei; Krieger, Jürgen; Große-Wilde, Ewald; Mißbach, Christine; Zhang, Long; Breer, Heinz

    2014-01-01

    The behaviour of the desert locust, Schistocera gregaria, is largely directed by volatile olfactory cues. The relevant odorants are detected by specialized antennal sensory neurons which project their sensory dendrites into hair-like structures, the sensilla. Generally, the responsiveness of the antennal chemosensory cells is determined by specific receptors which may be either odorant receptors (ORs) or variant ionotropic receptors (IRs). Previously, we demonstrated that in locust the co-receptor for ORs (ORco) is only expressed in cells of sensilla basiconica and sensilla trichodea, suggesting that cells in sensilla coeloconica may express different types of chemosensory receptors. In this study, we have identified the genes of S. gregaria which encode homologues of co-receptors for the variant ionotropic receptors, the subtypes IR8a and IR25a. It was found that both subtypes, SgreIR8a and SgreIR25a, are expressed in the antennae of all five nymphal stages and in adults. Attempts to assign the relevant cell types by means of in situ hybridization revealed that SgreIR8a and SgreIR25a are expressed in cells of sensilla coeloconica. Double fluorescence in situ hybridization experiments disclosed that the two IR-subtypes are co-expressed in some cells of this sensillum type. Expression of SgreIR25a was also found in some of the sensilla chaetica, however, neither SgreIR25a nor SgreIR8a was found to be expressed in sensilla basiconica and sensilla trichodea. This observation was substantiated by the results of double FISH experiments demonstrating that cells expressing SgreIR8a or SgreIR25a do not express ORco. These results support the notion that the antenna of the desert locust employs two different populations of OSNs to sense odors; cells which express IRs in sensilla coeloconica and cells which express ORs in sensilla basiconica and sensilla trichodea. PMID:24391446

  9. Involvement of glutamatergic N-methyl-d-aspartate receptors in the expression of increased head-dipping behaviors in the hole-board tests of olfactory bulbectomized mice.

    PubMed

    Hirose, Noritaka; Saitoh, Akiyoshi; Kamei, Junzo

    2016-10-01

    Olfactory bulbectomized (OB) mice produce agitated anxiety-like behaviors in the hole-board test, which was expressed by an increase in head-dipping counts and a decrease in head-dipping latencies. However, the associated mechanisms remain unclear. In the present study, MK-801 (10, 100μg/kg), a selective N-methyl-d-aspartate (NMDA) receptor antagonist, significantly and dose-dependently suppressed the increased head-dipping behaviors in OB mice, without affecting sham mice. Similar results were obtained with another selective NMDA receptor antagonist D-AP5 treatment in OB mice. On the other hand, muscimol, a selective aminobutyric acid type A (GABAA) receptor agonist produced no effects on these hyperemotional behaviors in OB mice at a dose (100μg/kg) that produced anxiolytic-like effects in sham mice. Interestingly, glutamine contents and glutamine/glutamate ratios were significantly increased in the amygdala and frontal cortex of OB mice compared to sham mice. Based on these results, we concluded that the glutamatergic NMDA receptors are involved in the expression of increased head-dipping behaviors in the hole-board tests of OB mice. Accordingly, the changes in glutamatergic transmission in frontal cortex and amygdala may play important roles in the expression of these abnormal behaviors in OB mice.

  10. Involvement of glutamatergic N-methyl-d-aspartate receptors in the expression of increased head-dipping behaviors in the hole-board tests of olfactory bulbectomized mice.

    PubMed

    Hirose, Noritaka; Saitoh, Akiyoshi; Kamei, Junzo

    2016-10-01

    Olfactory bulbectomized (OB) mice produce agitated anxiety-like behaviors in the hole-board test, which was expressed by an increase in head-dipping counts and a decrease in head-dipping latencies. However, the associated mechanisms remain unclear. In the present study, MK-801 (10, 100μg/kg), a selective N-methyl-d-aspartate (NMDA) receptor antagonist, significantly and dose-dependently suppressed the increased head-dipping behaviors in OB mice, without affecting sham mice. Similar results were obtained with another selective NMDA receptor antagonist D-AP5 treatment in OB mice. On the other hand, muscimol, a selective aminobutyric acid type A (GABAA) receptor agonist produced no effects on these hyperemotional behaviors in OB mice at a dose (100μg/kg) that produced anxiolytic-like effects in sham mice. Interestingly, glutamine contents and glutamine/glutamate ratios were significantly increased in the amygdala and frontal cortex of OB mice compared to sham mice. Based on these results, we concluded that the glutamatergic NMDA receptors are involved in the expression of increased head-dipping behaviors in the hole-board tests of OB mice. Accordingly, the changes in glutamatergic transmission in frontal cortex and amygdala may play important roles in the expression of these abnormal behaviors in OB mice. PMID:27353857

  11. Olfactory signaling in insects.

    PubMed

    Wicher, Dieter

    2015-01-01

    The detection of volatile chemical information in insects is performed by three types of olfactory receptors, odorant receptors (ORs), specific gustatory receptor (GR) proteins for carbon dioxide perception, and ionotropic receptors (IRs) which are related to ionotropic glutamate receptors. All receptors form heteromeric assemblies; an OR complex is composed of an odor-specific OrX protein and a coreceptor (Orco). ORs and GRs have a 7-transmembrane topology as for G protein-coupled receptors, but they are inversely inserted into the membrane. Ligand-gated ion channels (ionotropic receptors) and ORs operate as IRs activated by volatile chemical cues. ORs are evolutionarily young receptors, and they first appear in winged insects and seem to be evolved to allow an insect to follow sparse odor tracks during flight. In contrast to IRs, the ORs can be sensitized by repeated subthreshold odor stimulation. This process involves metabotropic signaling. Pheromone receptors are especially sensitive and require an accessory protein to detect the lipid-derived pheromone molecules. Signaling cascades involved in pheromone detection depend on intensity and duration of stimuli and underlie a circadian control. Taken together, detection and processing of volatile information in insects involve ionotropic as well as metabotropic mechanisms. Here, I review the cellular signaling events associated with detection of cognate ligands by the different types of odorant receptors.

  12. Individual olfactory perception reveals meaningful nonolfactory genetic information.

    PubMed

    Secundo, Lavi; Snitz, Kobi; Weissler, Kineret; Pinchover, Liron; Shoenfeld, Yehuda; Loewenthal, Ron; Agmon-Levin, Nancy; Frumin, Idan; Bar-Zvi, Dana; Shushan, Sagit; Sobel, Noam

    2015-07-14

    Each person expresses a potentially unique subset of ∼ 400 different olfactory receptor subtypes. Given that the receptors we express partially determine the odors we smell, it follows that each person may have a unique nose; to capture this, we devised a sensitive test of olfactory perception we termed the "olfactory fingerprint." Olfactory fingerprints relied on matrices of perceived odorant similarity derived from descriptors applied to the odorants. We initially fingerprinted 89 individuals using 28 odors and 54 descriptors. We found that each person had a unique olfactory fingerprint (P < 10(-10)), which was odor specific but descriptor independent. We could identify individuals from this pool using randomly selected sets of 7 odors and 11 descriptors alone. Extrapolating from this data, we determined that using 34 odors and 35 descriptors we could individually identify each of the 7 billion people on earth. Olfactory perception, however, fluctuates over time, calling into question our proposed perceptual readout of presumably stable genetic makeup. To test whether fingerprints remain informative despite this temporal fluctuation, building on the linkage between olfactory receptors and HLA, we hypothesized that olfactory perception may relate to HLA. We obtained olfactory fingerprints and HLA typing for 130 individuals, and found that olfactory fingerprint matching using only four odorants was significantly related to HLA matching (P < 10(-4)), such that olfactory fingerprints can save 32% of HLA tests in a population screen (P < 10(-6)). In conclusion, a precise measure of olfactory perception reveals meaningful nonolfactory genetic information.

  13. Cell-free expression, purification, and ligand-binding analysis of Drosophila melanogaster olfactory receptors DmOR67a, DmOR85b and DmORCO.

    PubMed

    Tegler, Lotta Tollstoy; Corin, Karolina; Hillger, Julia; Wassie, Brooke; Yu, Yanmei; Zhang, Shuguang

    2015-01-01

    Insects transmit numerous devastating diseases, including malaria, dengue fever, and sleeping sickness. Olfactory cues guide insects to their hosts, and are thus responsible for disease transmission. Understanding the molecular basis of insect olfaction could facilitate the development of interventions. The first step is to heterologously overexpress and purify insect olfactory receptors (ORs). This is challenging, as ORs are membrane proteins. Here, we show that insect ORs and their co-receptor can be expressed in an E. coli cell-free system. After immunoaffinity chromatography, the ORs are ~95% pure, and up to 1 mg/10 ml reaction is obtained. Circular dichroism together with microscale thermophoresis indicate that each receptor is properly folded, and can bind its respective ligand. This is the first time insect ORs have been expressed in an E. coli system. The methods described here could facilitate future structure-function studies, which may aid in developments to alleviate the suffering of millions caused by insect-transmitted diseases.

  14. Detection of explosives by olfactory sensory neurons.

    PubMed

    Corcelli, Angela; Lobasso, Simona; Lopalco, Patrizia; Dibattista, Michele; Araneda, Ricardo; Peterlin, Zita; Firestein, Stuart

    2010-03-15

    The response of olfactory sensory neurons to TNT and RDX as well as to some volatile organic compounds present in the vapors of antipersonnel landmines has been studied both in the pig and in the rat. GC/MS analyses of different plastic components of six different kinds of landmines were performed in order to identify the components of the "perfume" of mines. Studies on rat olfactory mucosa were carried out with electro-olfactogram and calcium imaging techniques, while changes in the cyclic adenosine monophosphate (cAMP) levels following exposure to odorants and explosives were used as a criterion to evaluate the interaction of TNT and RDX with olfactory receptors in a preparation of isolated pig olfactory cilia. These studies indicate that chemical compounds associated with explosives and explosive devices can activate mammalian olfactory receptors.

  15. Reduction in host-finding behaviour in fungus-infected mosquitoes is correlated with reduction in olfactory receptor neuron responsiveness

    PubMed Central

    2011-01-01

    Background Chemical insecticides against mosquitoes are a major component of malaria control worldwide. Fungal entomopathogens formulated as biopesticides and applied as insecticide residual sprays could augment current control strategies and mitigate the evolution of resistance to chemical-based insecticides. Methods Anopheles stephensi mosquitoes were exposed to Beauveria bassiana or Metarhizium acridum fungal spores and sub-lethal effects of exposure to fungal infection were studied, especially the potential for reductions in feeding and host location behaviours related to olfaction. Electrophysiological techniques, such as electroantennogram, electropalpogram and single sensillum recording techniques were then employed to investigate how fungal exposure affected the olfactory responses in mosquitoes. Results Exposure to B. bassiana caused significant mortality and reduced the propensity of mosquitoes to respond and fly to a feeding stimulus. Exposure to M. acridum spores induced a similar decline in feeding propensity, albeit more slowly than B. bassiana exposure. Reduced host-seeking responses following fungal exposure corresponded to reduced olfactory neuron responsiveness in both antennal electroantennogram and maxillary palp electropalpogram recordings. Single cell recordings from neurons on the palps confirmed that fungal-exposed behavioural non-responders exhibited significantly impaired responsiveness of neurons tuned specifically to 1-octen-3-ol and to a lesser degree, to CO2. Conclusions Fungal infection reduces the responsiveness of mosquitoes to host odour cues, both behaviourally and neuronally. These pre-lethal effects are likely to synergize with fungal-induced mortality to further reduce the capacity of mosquito populations exposed to fungal biopesticides to transmit malaria. PMID:21812944

  16. Biochemical Large-Scale Interaction Analysis of Murine Olfactory Receptors and Associated Signaling Proteins with Post-Synaptic Density 95, Drosophila Discs Large, Zona-Occludens 1 (PDZ) Domains*

    PubMed Central

    Jansen, Fabian; Kalbe, Benjamin; Scholz, Paul; Fränzel, Benjamin; Osterloh, Markus; Wolters, Dirk; Hatt, Hanns; Neuhaus, Eva Maria; Osterloh, Sabrina

    2015-01-01

    G protein-coupled receptors (GPCRs) constitute the largest family among mammalian membrane proteins and are capable of initiating numerous essential signaling cascades. Various GPCR-mediated pathways are organized into protein microdomains that can be orchestrated and regulated through scaffolding proteins, such as PSD-95/discs-large/ZO1 (PDZ) domain proteins. However, detailed binding characteristics of PDZ–GPCR interactions remain elusive because these interactions seem to be more complex than previously thought. To address this issue, we analyzed binding modalities using our established model system. This system includes the 13 individual PDZ domains of the multiple PDZ domain protein 1 (MUPP1; the largest PDZ protein), a broad range of murine olfactory receptors (a multifaceted gene cluster within the family of GPCRs), and associated olfactory signaling proteins. These proteins were analyzed in a large-scale peptide microarray approach and continuative interaction studies. As a result, we demonstrate that canonical binding motifs were not overrepresented among the interaction partners of MUPP1. Furthermore, C-terminal phosphorylation and distinct amino acid replacements abolished PDZ binding promiscuity. In addition to the described in vitro experiments, we identified new interaction partners within the murine olfactory epithelium using pull-down-based interactomics and could verify the partners through co-immunoprecipitation. In summary, the present study provides important insight into the complexity of the binding characteristics of PDZ–GPCR interactions based on olfactory signaling proteins, which could identify novel clinical targets for GPCR-associated diseases in the future. PMID:25979994

  17. Multiplex assessment of the positions of odorant receptor-specific glomeruli in the mouse olfactory bulb by serial two-photon tomography.

    PubMed

    Zapiec, Bolek; Mombaerts, Peter

    2015-10-27

    In the mouse, axons of olfactory sensory neurons (OSNs) that express the same odorant receptor (OR) gene coalesce into one or a few glomeruli in the olfactory bulb. The positions of OR-specific glomeruli are traditionally described as stereotyped. Here, we have assessed quantitatively the positions of OR-specific glomeruli using serial two-photon tomography, an automated method for whole-organ fluorescence imaging that integrates two-photon microscopy with serial microtome sectioning. Our strategy is multiplexed. By repeated crossing, we generated two strains of mice with gene-targeted mutations at four or five OR loci for a total of six ORs: MOR23 (Olfr16), mOR37A (Olfr155), M72 (Olfr160), P2 (Olfr17), MOR256-17 (Olfr15), and MOR28 (Olfr1507). Glomerular imaging relied on intrinsic fluorescence of GFP or DsRed, or on whole-mount immunofluorescence with antibodies against GFP, DsRed, or β-gal using the method of immunolabeling-enabled three-dimensional imaging of solvent-cleared organs (iDISCO). The high-resolution 3D-reconstructed datasets were segmented to identify the labeled glomeruli and to assess glomerular positional variability between the bulbs of one mouse (intraindividual) and among the bulbs of different mice (interindividual). In 26 mice aged 21 or 50 d or 10 wk, we made measurements of the positions of 352 glomeruli. We find that positional variability of glomeruli correlates with the OR: For instance, the medial MOR28 glomerular domain occupies a surface area that is an order of magnitude larger than the surface area of the medial MOR23 glomerular domain. Our results quantify the level of precision that is delivered by the mechanisms of OSN axon wiring, differentially for the various OSN populations expressing distinct OR genes. PMID:26450880

  18. Involvement of TRPV1 in the Olfactory Bulb in Rimonabant-Induced Olfactory Discrimination Deficit.

    PubMed

    Hu, Sherry Shu-Jung

    2016-02-29

    Rimonabant is well recognized as a cannabinoid CB₁ receptor antagonist/inverse agonist. Rimonabant not only antagonizes the effects induced by exogenous cannabinoids and endocannabinoids at CB₁ receptors, it also exerts several pharmacological and behavioral effects independent of CB₁ receptor inactivation. For example, rimonabant can function as a low-potency mixed agonist/antagonist of the transient receptor potential vanilloid receptor 1 (TRPV1). Hence, it is important to explain the underlying mechanisms of the diverse physiological effects induced by rimonabant with caution. Interestingly, CB₁ receptor has recently been suggested to play a role in olfactory functions. Olfaction not only is involved in food intake, visual perception and social interaction, but also is proposed as a putative marker for schizophrenia and autism. Therefore, the present study aimed to investigate whether CB₁ receptor and TRPV1 played a role in olfactory functions. We first used the genetic disruption approach to examine the role of CB₁ receptor in olfactory functions and found that CB₁ knockout mice exhibited olfactory discrimination deficit. However, it is important to point out that these CB₁ knockout mice, despite their normal locomotivity, displayed deficiencies in the olfactory foraging and novel object exploration tasks. These results imply that general exploratory behaviors toward odorant and odorless objects are compromised in CB₁ knockout mice. We next turned to the pharmacological approach to examine the role of CB₁ receptor and TRPV1 in olfactory functions. We found that the short-term administration of rimonabant, injected systemically or directly into the olfactory bulb (OB), impaired olfactory discrimination that was rescued by the TRPV1 antagonist capsazepine (CPZ), via the same route of rimonabant, in wild-type mice. These results suggest that TRPV1 in the OB is involved in rimonabant-induced olfactory discrimination deficit. However, the

  19. Mechanisms of permanent loss of olfactory receptor neurons induced by the herbicide 2,6-dichlorobenzonitrile: Effects on stem cells and noninvolvement of acute induction of the inflammatory cytokine IL-6

    SciTech Connect

    Xie, Fang; Fang, Cheng; Schnittke, Nikolai; Schwob, James E.; Ding, Xinxin

    2013-11-01

    We explored the mechanisms underlying the differential effects of two olfactory toxicants, the herbicide 2,6-dichlorobenzonitrile (DCBN) and the anti-thyroid drug methimazole (MMZ), on olfactory receptor neuron (ORN) regeneration in mouse olfactory epithelium (OE). DCBN, but not MMZ, induced inflammation-like pathological changes in OE, and DCBN increased interleukin IL-6 levels in nasal-wash fluid to much greater magnitude and duration than did MMZ. At 24 h after DCBN injection, the population of horizontal basal cells (HBCs; reserve, normally quiescent OE stem cells) lining the DMM became severely depleted as some of them detached from the basal lamina, and sloughed into the nasal cavity along with the globose basal cells (GBCs; heterogeneous population of stem and progenitor cells), neurons, and sustentacular cells of the neuroepithelium. In contrast, the layer of HBCs remained intact in MMZ-treated mice, as only the mature elements of the neuroepithelium were shed. Despite the respiratory metaplasia accompanying the greater severity of the DCBN lesion, residual HBCs that survived intoxication were activated by the injury and contributed to the metaplastic respiratory epithelium, as shown by tracing their descendants in a K5CreEr{sup T2}::fl(stop)TdTomato strain of mice in which recombination causes HBCs to express TdTomato in advance of the lesion. But, contrary to published observations with MMZ, the HBCs failed to form ORNs. A role for IL-6 in suppressing ORN regeneration in DCBN-treated mice was rejected by the failure of the anti-inflammatory drug dexamethasone to prevent the subsequent respiratory metaplasia in the DMM, suggesting that other factors lead to HBC neuro-incompetence. - Highlights: • The herbicide dichlobenil (DCBN) can damage olfactory epithelium stem cells. • Another olfactory toxicant, methimazole, leaves the olfactory stem cells intact. • DCBN, but not methimazole, induces a prolonged increase in nasal IL-6 levels. • Dexamethasone

  20. Aging in the olfactory system.

    PubMed

    Mobley, Arie S; Rodriguez-Gil, Diego J; Imamura, Fumiaki; Greer, Charles A

    2014-02-01

    With advancing age, the ability of humans to detect and discriminate odors declines. In light of the rapid progress in analyzing molecular and structural correlates of developing and adult olfactory systems, the paucity of information available on the aged olfactory system is startling. A rich literature documents the decline of olfactory acuity in aged humans, but the underlying cellular and molecular mechanisms are largely unknown. Using animal models, preliminary work is beginning to uncover differences between young and aged rodents that may help address the deficits seen in humans, but many questions remain unanswered. Recent studies of odorant receptor (OR) expression, synaptic organization, adult neurogenesis, and the contribution of cortical representation during aging suggest possible underlying mechanisms and new research directions.

  1. The Genetics of Non-conventional Wine Yeasts: Current Knowledge and Future Challenges

    PubMed Central

    Masneuf-Pomarede, Isabelle; Bely, Marina; Marullo, Philippe; Albertin, Warren

    2016-01-01

    Saccharomyces cerevisiae is by far the most widely used yeast in oenology. However, during the last decade, several other yeasts species has been purposed for winemaking as they could positively impact wine quality. Some of these non-conventional yeasts (Torulaspora delbrueckii, Metschnikowia pulcherrima, Pichia kluyveri, Lachancea thermotolerans, etc.) are now proposed as starters culture for winemakers in mixed fermentation with S. cerevisiae, and several others are the subject of various studies (Hanseniaspora uvarum, Starmerella bacillaris, etc.). Along with their biotechnological use, the knowledge of these non-conventional yeasts greatly increased these last 10 years. The aim of this review is to describe the last updates and the current state-of-art of the genetics of non-conventional yeasts (including S. uvarum, T. delbrueckii, S. bacillaris, etc.). We describe how genomics and genetics tools provide new data into the population structure and biodiversity of non-conventional yeasts in winemaking environments. Future challenges will lie on the development of selection programs and/or genetic improvement of these non-conventional species. We discuss how genetics, genomics and the advances in next-generation sequencing will help the wine industry to develop the biotechnological use of non-conventional yeasts to improve the quality and differentiation of wines. PMID:26793188

  2. Extreme expansion of the olfactory receptor gene repertoire in African elephants and evolutionary dynamics of orthologous gene groups in 13 placental mammals.

    PubMed

    Niimura, Yoshihito; Matsui, Atsushi; Touhara, Kazushige

    2014-09-01

    Olfactory receptors (ORs) detect odors in the environment, and OR genes constitute the largest multigene family in mammals. Numbers of OR genes vary greatly among species--reflecting the respective species' lifestyles--and this variation is caused by frequent gene gains and losses during evolution. However, whether the extent of gene gains/losses varies among individual gene lineages and what might generate such variation is unknown. To answer these questions, we used a newly developed phylogeny-based method to classify >10,000 intact OR genes from 13 placental mammal species into 781 orthologous gene groups (OGGs); we then compared the OGGs. Interestingly, African elephants had a surprisingly large repertoire (∼ 2000) of functional OR genes encoded in enlarged gene clusters. Additionally, OR gene lineages that experienced more gene duplication had weaker purifying selection, and Class II OR genes have evolved more dynamically than those in Class I. Some OGGs were highly expanded in a lineage-specific manner, while only three OGGs showed complete one-to-one orthology among the 13 species without any gene gains/losses. These three OGGs also exhibited highly conserved amino acid sequences; therefore, ORs in these OGGs may have physiologically important functions common to every placental mammal. This study provides a basis for inferring OR functions from evolutionary trajectory.

  3. Extreme expansion of the olfactory receptor gene repertoire in African elephants and evolutionary dynamics of orthologous gene groups in 13 placental mammals

    PubMed Central

    Matsui, Atsushi; Touhara, Kazushige

    2014-01-01

    Olfactory receptors (ORs) detect odors in the environment, and OR genes constitute the largest multigene family in mammals. Numbers of OR genes vary greatly among species—reflecting the respective species' lifestyles—and this variation is caused by frequent gene gains and losses during evolution. However, whether the extent of gene gains/losses varies among individual gene lineages and what might generate such variation is unknown. To answer these questions, we used a newly developed phylogeny-based method to classify >10,000 intact OR genes from 13 placental mammal species into 781 orthologous gene groups (OGGs); we then compared the OGGs. Interestingly, African elephants had a surprisingly large repertoire (∼2000) of functional OR genes encoded in enlarged gene clusters. Additionally, OR gene lineages that experienced more gene duplication had weaker purifying selection, and Class II OR genes have evolved more dynamically than those in Class I. Some OGGs were highly expanded in a lineage-specific manner, while only three OGGs showed complete one-to-one orthology among the 13 species without any gene gains/losses. These three OGGs also exhibited highly conserved amino acid sequences; therefore, ORs in these OGGs may have physiologically important functions common to every placental mammal. This study provides a basis for inferring OR functions from evolutionary trajectory. PMID:25053675

  4. Natural odor ligands for olfactory receptor neurons of the female mosquito Aedes aegypti: use of gas chromatography-linked single sensillum recordings.

    PubMed

    Ghaninia, Majid; Larsson, Mattias; Hansson, Bill S; Ignell, Rickard

    2008-09-01

    Female Aedes aegypti are vectors of dengue and yellow fever. Odor volatiles are the predominant cues that drive the host-seeking behavior of Ae. aegypti. Odorant molecules are detected and discriminated by olfactory receptor neurons (ORNs) housed in sensory hairs, sensilla, located on the antennae and maxillary palps. In a previous study, we used odor volatiles that are behaviorally and/or electrophysiologically active for Ae. aegypti and other mosquito species to show that antennal ORNs of female Ae. aegypti are divided into functionally different classes. In the present study, we have, for the first time, conducted gas chromatography-coupled single sensillum recordings (GC-SSR) from antennal trichoid and intermediate sensilla of female Ae. aegypti in order to screen for additional putative host attractants and repellents. We used headspace collections from biologically relevant sources, such as different human body parts (including feet, trunk regions and armpit), as well as a plant species used as a mosquito repellent, Nepeta faassenii. We found that a number of ORN types strongly responded to one or more of the biological extracts. GC-SSR recordings revealed several active components, which were subsequently identified through GC-linked mass spectrometry (GC-MS). Electrophysiologically active volatiles from human skin included heptanal, octanal, nonanal and decanal.

  5. Whole-cell recording from honeybee olfactory receptor neurons: ionic currents, membrane excitability and odourant response in developing workerbee and drone.

    PubMed

    Laurent, Stéphanie; Masson, Claudine; Jakob, Ingrid

    2002-04-01

    Whole-cell recording techniques were used to characterize ionic membrane currents and odourant responses in honeybee olfactory receptor neurons (ORNs) in primary cell culture. ORNs of workerbee (female) and drone (male) were isolated at an early stage of development before sensory axons connect to their target in the antennal lobe. The results collectively indicate that honeybee ORNs have electrical properties similar, but not necessarily identical to, those currently envisaged for ORNs of other species. Under voltage clamp at least four ionic currents could be distinguished. Inward currents were made of a fast transient, tetrodotoxin-sensitive sodium current. In some ORNs a cadmium-sensitive calcium current was detected. ORNs showed heterogeneity in their outward currents: either outward currents were made of a delayed rectifier type potassium current, which was partially blocked by tetraethyl ammonium or quinidine, or were composed of a delayed rectifier type and a transient calcium-dependent potassium current, which was cadmium-sensitive and abolished by removal of external calcium. The proportion of each of the two outward currents, however, was different within the ORNs of the two sexes suggesting a gender-specific functional heterogeneity. ORNs showed heterogeneity in action potential firing properties: depolarizing current steps elicited either one action potential or, as in most of the cells, it led to repetitive spiking. Action potentials were tetrodotoxin-sensitive suggesting they are carried by sodium. Odourant stimulation with different mixtures and pure substances evoked depolarizing receptor potentials with superimposed action potentials when spike threshold was reached. In summary, honeybee ORNs are remarkably mature at early stages in their development.

  6. Whole-cell recording from honeybee olfactory receptor neurons: ionic currents, membrane excitability and odourant response in developing workerbee and drone.

    PubMed

    Laurent, Stéphanie; Masson, Claudine; Jakob, Ingrid

    2002-04-01

    Whole-cell recording techniques were used to characterize ionic membrane currents and odourant responses in honeybee olfactory receptor neurons (ORNs) in primary cell culture. ORNs of workerbee (female) and drone (male) were isolated at an early stage of development before sensory axons connect to their target in the antennal lobe. The results collectively indicate that honeybee ORNs have electrical properties similar, but not necessarily identical to, those currently envisaged for ORNs of other species. Under voltage clamp at least four ionic currents could be distinguished. Inward currents were made of a fast transient, tetrodotoxin-sensitive sodium current. In some ORNs a cadmium-sensitive calcium current was detected. ORNs showed heterogeneity in their outward currents: either outward currents were made of a delayed rectifier type potassium current, which was partially blocked by tetraethyl ammonium or quinidine, or were composed of a delayed rectifier type and a transient calcium-dependent potassium current, which was cadmium-sensitive and abolished by removal of external calcium. The proportion of each of the two outward currents, however, was different within the ORNs of the two sexes suggesting a gender-specific functional heterogeneity. ORNs showed heterogeneity in action potential firing properties: depolarizing current steps elicited either one action potential or, as in most of the cells, it led to repetitive spiking. Action potentials were tetrodotoxin-sensitive suggesting they are carried by sodium. Odourant stimulation with different mixtures and pure substances evoked depolarizing receptor potentials with superimposed action potentials when spike threshold was reached. In summary, honeybee ORNs are remarkably mature at early stages in their development. PMID:11982625

  7. On the organization of olfactory and vomeronasal cortices.

    PubMed

    Martinez-Marcos, Alino

    2009-01-12

    Classically, the olfactory and vomeronasal pathways are thought to run in parallel non-overlapping axes in the forebrain subserving different functions. The olfactory and vomeronasal epithelia project to the main and accessory olfactory bulbs (primary projections), which in turn project to different areas of the telencephalon in a non-topographic fashion (secondary projections) and so on (tertiary projections). New data indicate that projections arising from the main and accessory olfactory bulbs converge widely in the rostral basal telencephalon. In contrast, in the vomeronasal system, cloning two classes of vomeronasal receptors (V1R and V2R) has led to the distinction of two anatomically and functionally independent pathways that reach some common, but also some different, targets in the amygdala. Tertiary projections from the olfactory and vomeronasal amygdalae are directed to the ventral striatum, which thus becomes a site for processing and potential convergence of chemosensory stimuli. Functional data indicate that the olfactory and vomeronasal systems are able to detect and process volatiles (presumptive olfactory cues) as well as pheromones in both epithelia and bulbs. Collectively, these data indicate that the anatomical and functional distinction between the olfactory and vomeronasal systems should be re-evaluated. Specifically, the recipient cortex should be reorganized to include olfactory, vomeronasal (convergent and V1R and V2R specific areas) and mixed (olfactory and vomeronasal) chemosensory cortices. This new perspective could help to unravel olfactory and vomeronasal interactions in behavioral paradigms.

  8. BE360, a new selective estrogen receptor modulator, produces antidepressant and antidementia effects through the enhancement of hippocampal cell proliferation in olfactory bulbectomized mice.

    PubMed

    Nakagawasai, Osamu; Nemoto, Wataru; Onogi, Hiroshi; Moriya, Takahiro; Lin, Jia-Rong; Odaira, Takayo; Yaoita, Fukie; Ogawa, Takumi; Ohta, Kiminori; Endo, Yasuyuki; Tan-No, Koichi

    2016-01-15

    We have reported that the carborane compound BE360 is a novel selective estrogen receptor modulator and new therapy option for osteoporosis. The aim of this study was to explore the effects and underlying mechanisms of BE360 on depressive-like behavior and memory impairment in the olfactory bulbectomized (OBX) mice, an experimental animal model of depression and dementia. BE360 was administered subcutaneously to mice using a mini-osmotic pump for 2 weeks. Depressive-like behavior was measured as the reduced intake of a sweet solution in the sucrose preference test. Short-term memory was assessed using the Y-maze test. Cell proliferation was assessed by the analysis of cells expressing 5-bromo-2'-deoxyuridine (BrdU) uptake. The expression of phosphorylated cyclic-AMP response element binding protein (pCREB) and brain-derived neurotrophic factor (BDNF) were measured by immunoblot. The depressive-like behavior and memory impairment in OBX mice were improved by the chronic treatment with BE360. Immunohistochemical analysis showed that the number of BrdU-positive cells in the dentate gyrus of the hippocampus significantly decreased in OBX mice whereas they increased after the chronic treatment with BE360. Immunoblotting studies revealed that pCREB and BDNF were significantly increased in the hippocampus of OBX mice treated with BE360. The present study has shown that BE360 has antidepressant and antidementia effects characterized by hippocampal cell proliferation potentially activated via CREB/BDNF signaling pathways. These results indicate that BE360 may have valuable therapeutic potential against depression and neurodegenerative diseases. PMID:26497104

  9. Paradoxical mineralocorticoid receptor-mediated effect in fear memory encoding and expression of rats submitted to an olfactory fear conditioning task.

    PubMed

    Souza, Rimenez R; Dal Bó, Silvia; de Kloet, E Ronald; Oitzl, Melly S; Carobrez, Antonio P

    2014-04-01

    There is general agreement that the substantial modification in memory and motivational states exerted by corticosteroids after a traumatic experience is mediated in complementary manner by the mineralocorticoid (MR) and glucocorticoid (GR) receptors. Here we tested the hypothesis that pharmacological manipulation of MR activity would affect behavioral strategy and information storage in an olfactory fear conditioning (OFC) task. Male Wistar rats were submitted to the OFC with different training intensities. We observed that following high intensity OFC acquisition, a set of defensive coping strategies, which includes avoidance and risk assessment behaviors, was elicited when subjects were exposed to the conditioned stimulus (CS) 48 h later. In addition, following either OFC acquisition or retrieval (CS-I test) a profound corticosterone secretion was also detected. Systemic administration of the MR antagonist spironolactone altered the behavioral coping style irrespective the antagonist was administered 60 min prior to the acquisition or before the retrieval session. Surprisingly, the MR agonist fludrocortisone given 60 min prior to acquisition or retrieval of OFC had similar effects as the antagonist. In addition, post-training administration of fludrocortisone, following a weak training procedure, facilitated the consolidation of OFC. Fludrocortisone rather than spironolactone reduced serum corticosterone levels, suggesting that, at least in part, the effects of the MR agonist may derive from additional GR-mediated HPA-axis suppression. In conclusion, the present study suggests the involvement of the MR in the fine-tuning of behavioral adaptation necessary for optimal information storage and expression, as revealed by the marked alterations in the risk assessment behavior.

  10. The sense of smell: multiple olfactory subsystems.

    PubMed

    Breer, H; Fleischer, J; Strotmann, J

    2006-07-01

    The mammalian olfactory system is not uniformly organized but consists of several subsystems each of which probably serves distinct functions. Not only are the two major nasal chemosensory systems, the vomeronasal organ and the main olfactory epithelium, structurally and functionally separate entities, but the latter is further subcompartimentalized into overlapping expression zones and projection-related subzones. Moreover, the populations of 'OR37' neurons not only express a unique type of olfactory receptors but also are segregated in a cluster-like manner and generally project to only one receptor-specific glomerulus. The septal organ is an island of sensory epithelium on the nasal septum positioned at the nasoplatine duct; it is considered as a 'mini-nose' with dual function. A specific chemosensory function of the most recently discovered subsystem, the so-called Grueneberg ganglion, is based on the expression of olfactory marker protein and the axonal projections to defined glomeruli within the olfactory bulb. This complexity of distinct olfactory subsystems may be one of the features determining the enormous chemosensory capacity of the sense of smell.

  11. Relation of the volume of the olfactory bulb to psychophysical measures of olfactory function.

    PubMed

    Mazal, Patricia Portillo; Haehner, Antje; Hummel, Thomas

    2016-01-01

    The aim of this review is to investigate whether changes in olfactory bulb volume relate to changes in specific olfactory functions. We studied currently available peer-reviewed articles on the volume of the human olfactory bulb that also included a psychophysical measure of olfactory function. In the present review, we observed a very clear and consistent correlation between general olfactory function and olfactory bulb (OB) volume. We were not able to find a clear relationship between a specific smell component and OB volume, even when analyzing pathologic conditions separately. In some cases, changes were observed for different subtests, but these changes did not significantly correlate with OB volume or had only a borderline correlation. In other cases, we found contradictory data. Several factors may contribute to the difficulties in finding correlations with the different components of smell: (1) the OB volume may be influenced by information from olfactory receptor neurons (bottom-up effect), information from central nervous system (top-down effect) and by direct damage; (2) most pathologic conditions affect more than one area of the olfactory pathway; (3) small sample sizes of hyposmic subjects were used. We believe that it is necessary to do further studies with larger numbers of subjects to answer the currently investigated question.

  12. Microbial Terroir in Chilean Valleys: Diversity of Non-conventional Yeast

    PubMed Central

    Jara, Carla; Laurie, V. Felipe; Mas, Albert; Romero, Jaime

    2016-01-01

    In this study, the presence of non-conventional yeast associated with vineyards located between latitudes 30°S and 36°S was examined, including the valleys of Limarí, Casablanca, Maipo, Colchagua, Maule, and Itata. The microbial fingerprinting in each valley was examined based on the specific quantification of yeast of enological interest. Grape–berries were sampled to evaluate the presence and load of non-conventional yeast with enological potential, such as Metschnikowia, Hanseniaspora, Torulaspora, Debaryomyces, Meyerozyma, and Rhodotorula. These yeasts were present in all vineyards studied but with varying loads depending on the valley sampled. No identical fingerprints were observed; however, similarities and differences could be observed among the microbial profiles of each valley. A co-variation in the loads of Metschnikowia and Hanseniaspora with latitude was observed, showing high loads in the Casablanca and Itata valleys, which was coincident with the higher relative humidity or rainfall of those areas. Non-conventional yeasts were also isolated and identified after sequencing molecular markers. Potentially good aromatic properties were also screened among the isolates, resulting in the selection of mostly Metschnikowia and Hanseniaspora isolates. Finally, our results suggest that microbial terroir might be affected by climatic conditions such as relative humidity and rainfall, especially impacting the load of non-conventional yeast. In this study, the microbial fingerprint for yeast in Chilean vineyards is reported for the first time revealing an opportunity to study the contribution of this assembly of microorganisms to the final product. PMID:27242693

  13. Advanced Techniques for Reservoir Simulation and Modeling of Non-Conventional Wells

    SciTech Connect

    Durlofsky, Louis J.

    2000-08-28

    This project targets the development of (1) advanced reservoir simulation techniques for modeling non-conventional wells; (2) improved techniques for computing well productivity (for use in reservoir engineering calculations) and well index (for use in simulation models), including the effects of wellbore flow; and (3) accurate approaches to account for heterogeneity in the near-well region.

  14. Achievement Evaluation within a Non-Conventional Framework: Some Experiences in Physics and Humour

    ERIC Educational Resources Information Center

    Worner, C. H.; Romero, A.; Bustamante, G.

    2010-01-01

    An achievement evaluation of a non-conventional physics course for liberal arts students is presented. The theoretical ground for this course focuses on the use of humour as a teaching tool. Preliminary evidence shows that a learning process is accomplished. (Contains 1 table and 3 figures.)

  15. Advanced Techniques for Reservoir Simulation and Modeling of Non-Conventional Wells

    SciTech Connect

    Durlofsky, Louis J.; Aziz, Khalid

    2001-08-23

    Research results for the second year of this project on the development of improved modeling techniques for non-conventional (e.g., horizontal, deviated or multilateral) wells were presented. The overall program entails the development of enhanced well modeling and general simulation capabilities. A general formulation for black-oil and compositional reservoir simulation was presented.

  16. Microbial Terroir in Chilean Valleys: Diversity of Non-conventional Yeast.

    PubMed

    Jara, Carla; Laurie, V Felipe; Mas, Albert; Romero, Jaime

    2016-01-01

    In this study, the presence of non-conventional yeast associated with vineyards located between latitudes 30°S and 36°S was examined, including the valleys of Limarí, Casablanca, Maipo, Colchagua, Maule, and Itata. The microbial fingerprinting in each valley was examined based on the specific quantification of yeast of enological interest. Grape-berries were sampled to evaluate the presence and load of non-conventional yeast with enological potential, such as Metschnikowia, Hanseniaspora, Torulaspora, Debaryomyces, Meyerozyma, and Rhodotorula. These yeasts were present in all vineyards studied but with varying loads depending on the valley sampled. No identical fingerprints were observed; however, similarities and differences could be observed among the microbial profiles of each valley. A co-variation in the loads of Metschnikowia and Hanseniaspora with latitude was observed, showing high loads in the Casablanca and Itata valleys, which was coincident with the higher relative humidity or rainfall of those areas. Non-conventional yeasts were also isolated and identified after sequencing molecular markers. Potentially good aromatic properties were also screened among the isolates, resulting in the selection of mostly Metschnikowia and Hanseniaspora isolates. Finally, our results suggest that microbial terroir might be affected by climatic conditions such as relative humidity and rainfall, especially impacting the load of non-conventional yeast. In this study, the microbial fingerprint for yeast in Chilean vineyards is reported for the first time revealing an opportunity to study the contribution of this assembly of microorganisms to the final product. PMID:27242693

  17. Achievement evaluation within a non-conventional framework: some experiences in physics and humour

    NASA Astrophysics Data System (ADS)

    Wörner, C. H.; Romero, A.; Bustamante, G.

    2010-09-01

    An achievement evaluation of a non-conventional physics course for liberal arts students is presented. The theoretical ground for this course focuses on the use of humour as a teaching tool. Preliminary evidence shows that a learning process is accomplished.

  18. Microbial Terroir in Chilean Valleys: Diversity of Non-conventional Yeast.

    PubMed

    Jara, Carla; Laurie, V Felipe; Mas, Albert; Romero, Jaime

    2016-01-01

    In this study, the presence of non-conventional yeast associated with vineyards located between latitudes 30°S and 36°S was examined, including the valleys of Limarí, Casablanca, Maipo, Colchagua, Maule, and Itata. The microbial fingerprinting in each valley was examined based on the specific quantification of yeast of enological interest. Grape-berries were sampled to evaluate the presence and load of non-conventional yeast with enological potential, such as Metschnikowia, Hanseniaspora, Torulaspora, Debaryomyces, Meyerozyma, and Rhodotorula. These yeasts were present in all vineyards studied but with varying loads depending on the valley sampled. No identical fingerprints were observed; however, similarities and differences could be observed among the microbial profiles of each valley. A co-variation in the loads of Metschnikowia and Hanseniaspora with latitude was observed, showing high loads in the Casablanca and Itata valleys, which was coincident with the higher relative humidity or rainfall of those areas. Non-conventional yeasts were also isolated and identified after sequencing molecular markers. Potentially good aromatic properties were also screened among the isolates, resulting in the selection of mostly Metschnikowia and Hanseniaspora isolates. Finally, our results suggest that microbial terroir might be affected by climatic conditions such as relative humidity and rainfall, especially impacting the load of non-conventional yeast. In this study, the microbial fingerprint for yeast in Chilean vineyards is reported for the first time revealing an opportunity to study the contribution of this assembly of microorganisms to the final product.

  19. The complete human olfactory subgenome.

    PubMed

    Glusman, G; Yanai, I; Rubin, I; Lancet, D

    2001-05-01

    Olfactory receptors likely constitute the largest gene superfamily in the vertebrate genome. Here we present the nearly complete human olfactory subgenome elucidated by mining the genome draft with gene discovery algorithms. Over 900 olfactory receptor genes and pseudogenes (ORs) were identified, two-thirds of which were not annotated previously. The number of extrapolated ORs is in good agreement with previous theoretical predictions. The sequence of at least 63% of the ORs is disrupted by what appears to be a random process of pseudogene formation. ORs constitute 17 gene families, 4 of which contain more than 100 members each. "Fish-like" Class I ORs, previously considered a relic in higher tetrapods, constitute as much as 10% of the human repertoire, all in one large cluster on chromosome 11. Their lower pseudogene fraction suggests a functional significance. ORs are disposed on all human chromosomes except 20 and Y, and nearly 80% are found in clusters of 6-138 genes. A novel comparative cluster analysis was used to trace the evolutionary path that may have led to OR proliferation and diversification throughout the genome. The results of this analysis suggest the following genome expansion history: first, the generation of a "tetrapod-specific" Class II OR cluster on chromosome 11 by local duplication, then a single-step duplication of this cluster to chromosome 1, and finally an avalanche of duplication events out of chromosome 1 to most other chromosomes. The results of the data mining and characterization of ORs can be accessed at the Human Olfactory Receptor Data Exploratorium Web site (http://bioinfo.weizmann.ac.il/HORDE). PMID:11337468

  20. The complete human olfactory subgenome.

    PubMed

    Glusman, G; Yanai, I; Rubin, I; Lancet, D

    2001-05-01

    Olfactory receptors likely constitute the largest gene superfamily in the vertebrate genome. Here we present the nearly complete human olfactory subgenome elucidated by mining the genome draft with gene discovery algorithms. Over 900 olfactory receptor genes and pseudogenes (ORs) were identified, two-thirds of which were not annotated previously. The number of extrapolated ORs is in good agreement with previous theoretical predictions. The sequence of at least 63% of the ORs is disrupted by what appears to be a random process of pseudogene formation. ORs constitute 17 gene families, 4 of which contain more than 100 members each. "Fish-like" Class I ORs, previously considered a relic in higher tetrapods, constitute as much as 10% of the human repertoire, all in one large cluster on chromosome 11. Their lower pseudogene fraction suggests a functional significance. ORs are disposed on all human chromosomes except 20 and Y, and nearly 80% are found in clusters of 6-138 genes. A novel comparative cluster analysis was used to trace the evolutionary path that may have led to OR proliferation and diversification throughout the genome. The results of this analysis suggest the following genome expansion history: first, the generation of a "tetrapod-specific" Class II OR cluster on chromosome 11 by local duplication, then a single-step duplication of this cluster to chromosome 1, and finally an avalanche of duplication events out of chromosome 1 to most other chromosomes. The results of the data mining and characterization of ORs can be accessed at the Human Olfactory Receptor Data Exploratorium Web site (http://bioinfo.weizmann.ac.il/HORDE).

  1. Calcium signals in olfactory neurons.

    PubMed

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness. PMID:7488645

  2. Calcium signals in olfactory neurons.

    PubMed

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  3. Olfactory system and demyelination.

    PubMed

    Garcia-Gonzalez, D; Murcia-Belmonte, V; Clemente, D; De Castro, F

    2013-09-01

    Within the central nervous system, the olfactory system represents one of the most exciting scenarios since it presents relevant examples of long-life sustained neurogenesis and continuous axonal outgrowth from the olfactory epithelium with the subsequent plasticity phenomena in the olfactory bulb. The olfactory nerve is composed of nonmyelinated axons with interesting ontogenetic interpretations. However, the centripetal projections from the olfactory bulb are myelinated axons which project to more caudal areas along the lateral olfactory tract. In consequence, demyelination has not been considered as a possible cause of the olfactory symptoms in those diseases in which this sense is impaired. One prototypical example of an olfactory disease is Kallmann syndrome, in which different mutations give rise to combined anosmia and hypogonadotropic hypogonadism, together with different satellite symptoms. Anosmin-1 is the extracellular matrix glycoprotein altered in the X-linked form of this disease, which participates in cell adhesion and migration, and axonal outgrowth in the olfactory system and in other regions of the central nervous system. Recently, we have described a new patho-physiological role of this protein in the absence of spontaneous remyelination in multiple sclerosis. In the present review, we hypothesize about how both main and satellite neurological symptoms of Kallmann syndrome may be explained by alterations in the myelination. We revisit the relationship between the olfactory system and myelin highlighting that minor histological changes should not be forgotten as putative causes of olfactory malfunction.

  4. Inhibition of Inflammation-Associated Olfactory Loss by Etanercept in an Inducible Olfactory Inflammation Mouse Model

    PubMed Central

    Jung, Yong Gi; Lane, Andrew P.

    2016-01-01

    Objective To determine the effect of a soluble human tumor necrosis factor alpha (TNF-α) receptor blocker (Etanercept) on an inducible olfactory inflammation (IOI) mouse model Study Design An in vivo study using a transgenic mouse model Setting Research laboratory Subjects and Methods To study the impact of chronic inflammation on the olfactory system, a transgenic mouse model of chronic rhinosinusitis (CRS)-associated olfactory loss was utilized (IOI mouse), expressing TNF-α in a temporally-controlled fashion specifically within the olfactory epithelium. In one group of mice (n=4), Etanercept was injected intraperitoneally (100 µg/dose, 3 times/week) concurrent with a 2-week period of TNF-α expression. A second group of mice (n=2) underwent induction of TNF-α expression for 8 weeks, with Etanercept treatment administered during the final 2 weeks of inflammation. Olfactory function was assayed by elecro-olfactogram (EOG), and olfactory tissue was processed for histology and immunohistochemical staining. Each group was compared with equal number of control group. Results Compared to non-treated IOI mice, Etanercept -treated IOI mice showed significantly improved EOG responses after 2 weeks (p<0.001). After 8 weeks of induced inflammation, there was massive loss of olfactory epithelium and no EOG response in non-treated IOI mice. However, in Etanercept - treated mice, regeneration of olfactory epithelium was observed. Conclusion Concomitant administration of Etanercept in IOI mice results in interruption of TNF-α-induced olfactory loss and induction of neuroepithelial regeneration. This demonstrates that Etanercept has potential utility as a tool for elucidating the role of TNF-α in other olfactory inflammation models. PMID:26932943

  5. The olfactory apparatus of the bandicoot (Isoodon macrourus): fine structure and presence of a septal olfactory organ.

    PubMed Central

    Kratzing, J E

    1978-01-01

    The structure and extent of olfactory epithelium in the bandicoot (Isoodon macrourus) were examined by light and electron microscopy. Sensory epithelium covers most of the dorsal conchae, though non-sensory epithelium lines ventrally facing scrolls. The middle conchae are partly covered by olfactory epithelium, the proportion of olfactory to ciliated respiratory epithelium increasing caudally. Ventral conchae are lined by non-sensory ciliated epithelium. The nasal septum ends short of the floor of the nasal cavity in its caudal two thirds. It is covered dorsally by olfactory epithelium. The ventral margin has rounded lateral extensions which carry the isolated strips of olfactory epithelium which form the septal olfactory organ. The fine structure of the olfactory epithelium is the same in all areas. Cell types include olfactory receptors, supporting cells, two types of basal cell and rarer pale and brush cells. There is considerable morphological variation in olfactory cells, and evidence suggestive of continuing turnover in the receptor cell population. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:640961

  6. Anatomical specializations for enhanced olfactory sensitivity in kiwi, Apteryx mantelli.

    PubMed

    Corfield, Jeremy R; Eisthen, Heather L; Iwaniuk, Andrew N; Parsons, Stuart

    2014-01-01

    The ability to function in a nocturnal and ground-dwelling niche requires a unique set of sensory specializations. The New Zealand kiwi has shifted away from vision, instead relying on auditory and tactile stimuli to function in its environment and locate prey. Behavioral evidence suggests that kiwi also rely on their sense of smell, using olfactory cues in foraging and possibly also in communication and social interactions. Anatomical studies appear to support these observations: the olfactory bulbs and tubercles have been suggested to be large in the kiwi relative to other birds, although the extent of this enlargement is poorly understood. In this study, we examine the size of the olfactory bulbs in kiwi and compare them with 55 other bird species, including emus, ostriches, rheas, tinamous, and 2 extinct species of moa (Dinornithiformes). We also examine the cytoarchitecture of the olfactory bulbs and olfactory epithelium to determine if any neural specializations beyond size are present that would increase olfactory acuity. Kiwi were a clear outlier in our analysis, with olfactory bulbs that are proportionately larger than those of any other bird in this study. Emus, close relatives of the kiwi, also had a relative enlargement of the olfactory bulbs, possibly supporting a phylogenetic link to well-developed olfaction. The olfactory bulbs in kiwi are almost in direct contact with the olfactory epithelium, which is indeed well developed and complex, with olfactory receptor cells occupying a large percentage of the epithelium. The anatomy of the kiwi olfactory system supports an enhancement for olfactory sensitivities, which is undoubtedly associated with their unique nocturnal niche. PMID:25376305

  7. Anatomical specializations for enhanced olfactory sensitivity in kiwi, Apteryx mantelli.

    PubMed

    Corfield, Jeremy R; Eisthen, Heather L; Iwaniuk, Andrew N; Parsons, Stuart

    2014-01-01

    The ability to function in a nocturnal and ground-dwelling niche requires a unique set of sensory specializations. The New Zealand kiwi has shifted away from vision, instead relying on auditory and tactile stimuli to function in its environment and locate prey. Behavioral evidence suggests that kiwi also rely on their sense of smell, using olfactory cues in foraging and possibly also in communication and social interactions. Anatomical studies appear to support these observations: the olfactory bulbs and tubercles have been suggested to be large in the kiwi relative to other birds, although the extent of this enlargement is poorly understood. In this study, we examine the size of the olfactory bulbs in kiwi and compare them with 55 other bird species, including emus, ostriches, rheas, tinamous, and 2 extinct species of moa (Dinornithiformes). We also examine the cytoarchitecture of the olfactory bulbs and olfactory epithelium to determine if any neural specializations beyond size are present that would increase olfactory acuity. Kiwi were a clear outlier in our analysis, with olfactory bulbs that are proportionately larger than those of any other bird in this study. Emus, close relatives of the kiwi, also had a relative enlargement of the olfactory bulbs, possibly supporting a phylogenetic link to well-developed olfaction. The olfactory bulbs in kiwi are almost in direct contact with the olfactory epithelium, which is indeed well developed and complex, with olfactory receptor cells occupying a large percentage of the epithelium. The anatomy of the kiwi olfactory system supports an enhancement for olfactory sensitivities, which is undoubtedly associated with their unique nocturnal niche.

  8. Olfactory Mucosa Tissue Based Biosensor for Bioelectronic Nose

    NASA Astrophysics Data System (ADS)

    Liu, Qingjun; Ye, Weiwei; Yu, Hui; Hu, Ning; Cai, Hua; Wang, Ping

    2009-05-01

    Biological olfactory system can distinguish thousands of odors. In order to realize the biomimetic design of electronic nose on the principle of mammalian olfactory system, we have reported bioelectronic nose based on cultured olfactory cells. In this study, the electrical property of the tissue-semiconductor interface was analyzed by the volume conductor theory and the sheet conductor model. Olfactory mucosa tissue of rat was isolated and fixed on the surface of the light-addressable potentiometric sensor (LAPS), with the natural stations of the neuronal populations and functional receptor unit of the cilia well reserved. By the extracellular potentials of the olfactory receptor cells of the mucosa tissue monitored, both the simulation and the experimental results suggested that this tissue-semiconductor hybrid system was sensitive to odorants stimulation.

  9. The Olfactory Receptor OR51E1 Is Present along the Gastrointestinal Tract of Pigs, Co-Localizes with Enteroendocrine Cells and Is Modulated by Intestinal Microbiota

    PubMed Central

    Priori, Davide; Colombo, Michela; Clavenzani, Paolo; Jansman, Alfons J. M.; Lallès, Jean-Paul; Trevisi, Paolo; Bosi, Paolo

    2015-01-01

    The relevance of the butyrate-sensing olfactory receptor OR51E1 for gastrointestinal (GIT) functioning has not been considered so far. We investigated in young pigs the distribution of OR51E1 along the GIT, its relation with some endocrine markers, its variation with age and after interventions affecting the gut environment and intestinal microbiota. Immuno-reactive cells for OR51E1 and chromogranin A (CgA) were counted in cardial (CA), fundic (FU), pyloric (PL) duodenal (DU), jejunal (JE), ileal (IL), cecal (CE), colonic (CO) and rectal (RE) mucosae. OR51E1 co-localization with serotonin (5HT) and peptide YY (PYY) were evaluated in PL and CO respectively. FU and PL tissues were also sampled from 84 piglets reared from sows receiving either or not oral antibiotics (amoxicillin) around parturition, and sacrificed at days 14, 21, 28 (weaning) and 42 of age. JE samples were also obtained from 12 caesarean-derived piglets that were orally associated with simple (SA) or complex (CA) microbiota in the postnatal phase, and of which on days 26–37 of age jejunal loops were perfused for 8 h with enterotoxigenic Escherichia coli F4 (ETEC), Lactobacillus amylovorus or saline (CTRL). Tissue densities of OR51E1+ cells were in decreasing order: PL=DU>FU=CA>JE=IL=CE=CO=RE. OR51E1+ cells showed an enteroendocrine nature containing gastrointestinal hormones such as PYY or 5HT. OR51E1 gene expression in PL and FU increased during and after the suckling period (p<0.05). It was marginally reduced in offspring from antibiotic-treated sows (tendency, p=0.073), vs. control. Jejunal OR51E1 gene expression was reduced in piglets early associated with SA, compared with CA, and in ETEC-perfused loops vs. CTRL (p<0.01). Our results indicate that OR51E1 is related to GIT enteroendocrine activity. Moreover age, pathogen challenge and dietary manipulations influencing the gastrointestinal luminal microenvironment significantly affect the OR51E1 gene expression in GIT tissues presumably in

  10. Awareness and Use of Non-conventional Tobacco Products Among U.S. Students, 2012

    PubMed Central

    Wang, Baoguang; King, Brian A.; Corey, Catherine G.; Arrazola, René A.; Johnson, Sarah E.

    2015-01-01

    Background Increasing diversity of the tobacco product landscape, including electronic cigarettes (e-cigarettes), hookah, snus, and dissolvable tobacco products (dissolvables), raises concerns about the public health impact of these non-conventional tobacco products among youth. Purpose This study assessed awareness, ever use, and current use of non-conventional tobacco products among U.S. students in 2012, overall and by demographic and tobacco use characteristics. Methods Data from the 2012 National Youth Tobacco Survey, a nationally representative survey of U.S. middle and high school students, were analyzed in 2013. Prevalence of awareness, ever use, and current use of e-cigarettes, hookah, snus, and dissolvables were calculated overall and by sex, school level, race/ethnicity, and conventional tobacco product use, including cigarettes, cigars, or smokeless tobacco (chewing tobacco, snuff, or dip). Results Overall, 50.3% of students were aware of e-cigarettes; prevalence of ever and current use of e-cigarettes was 6.8% and 2.1%, respectively. Awareness of hookah was 41.2% among all students, and that of ever and current use were 8.9% and 3.6%, respectively. Overall awareness; ever; and current use of snus (32%, 5.3%, 1.7%, respectively) and dissolvables (19.3%, 2.0%, 0.7%, respectively) were generally lower than those of e-cigarettes or hookah. Conventional tobacco product users were more likely to be aware of and to use non-conventional tobacco products. Conclusions Many U.S. students are aware of and use non-conventional tobacco products. Evidence-based interventions should be implemented to prevent and reduce all tobacco use among youth. PMID:25044194

  11. Non-Conventional Yeast Strains Increase the Aroma Complexity of Bread

    PubMed Central

    Rezaei, Mohammad Naser; Steensels, Jan; Courtin, Christophe M.; Verstrepen, Kevin J.

    2016-01-01

    Saccharomyces cerevisiae is routinely used yeast in food fermentations because it combines several key traits, including fermentation efficiency and production of desirable flavors. However, the dominance of S. cerevisiae in industrial fermentations limits the diversity in the aroma profiles of the end products. Hence, there is a growing interest in non-conventional yeast strains that can help generate the diversity and complexity desired in today’s diversified and consumer-driven markets. Here, we selected a set of non-conventional yeast strains to examine their potential for bread fermentation. Here, we tested ten non-conventional yeasts for bread fermentation, including two Saccharomyces species that are not currently used in bread making and 8 non-Saccharomyces strains. The results show that Torulaspora delbrueckii and Saccharomyces bayanus combine satisfactory dough fermentation with an interesting flavor profile. Sensory analysis and HS-SPME-GC-MS analysis confirmed that these strains produce aroma profiles that are very different from that produced by a commercial bakery strain. Moreover, bread produced with these yeasts was preferred by a majority of a trained sensory panel. These results demonstrate the potential of T. delbrueckii and S. bayanus as alternative yeasts for bread dough leavening, and provide a general experimental framework for the evaluation of more yeasts and bacteria. PMID:27776154

  12. [Olfactory sensory perception].

    PubMed

    Fuentes, Aler; Fresno, María Javiera; Santander, Hugo; Valenzuela, Saúl; Gutiérrez, Mario Felipe; Miralles, Rodolfo

    2011-03-01

    The five senses have had a fundamental importance for survival and socialization of human beings. From an evolutionary point of view the sense of smell is the oldest. This sense has a strong representation within the genome, allowing the existence of many types of receptors that allow us to capture multiple volatile odor producing molecules, sending electrical signals to higher centers to report the outside world. Several cortical areas are activated in the brain, which are interconnected to form an extensive and complex neural network, linking for example, areas involved with memory and emotions, thus giving this sense of perceptual richness. While the concept of flavor is largely related to the sense of taste, smell provides the necessary integration with the rest of the senses and higher functions. Fully understanding the sense of smell is relevant to health professionals. Knowing the characteristics of the receptors, the transduction processes and convergence of information in the higher centers involved, we can properly detect olfactory disorders in our patients. PMID:21879170

  13. [Olfactory sensory perception].

    PubMed

    Fuentes, Aler; Fresno, María Javiera; Santander, Hugo; Valenzuela, Saúl; Gutiérrez, Mario Felipe; Miralles, Rodolfo

    2011-03-01

    The five senses have had a fundamental importance for survival and socialization of human beings. From an evolutionary point of view the sense of smell is the oldest. This sense has a strong representation within the genome, allowing the existence of many types of receptors that allow us to capture multiple volatile odor producing molecules, sending electrical signals to higher centers to report the outside world. Several cortical areas are activated in the brain, which are interconnected to form an extensive and complex neural network, linking for example, areas involved with memory and emotions, thus giving this sense of perceptual richness. While the concept of flavor is largely related to the sense of taste, smell provides the necessary integration with the rest of the senses and higher functions. Fully understanding the sense of smell is relevant to health professionals. Knowing the characteristics of the receptors, the transduction processes and convergence of information in the higher centers involved, we can properly detect olfactory disorders in our patients.

  14. Protein kinase C sensitizes olfactory adenylate cyclase

    PubMed Central

    1993-01-01

    Effects of neurotransmitters on cAMP-mediated signal transduction in frog olfactory receptor cells (ORCs) were studied using in situ spike recordings and radioimmunoassays. Carbachol, applied to the mucosal side of olfactory epithelium, amplified the electrical response of ORCs to cAMP-generating odorants, but did not affect unstimulated cells. A similar augmentation of odorant response was observed in the presence of phorbol dibutyrate (PDBu), an activator of protein kinase C (PKC). The electrical response to forskolin, an activator of adenylate cyclase (AC), was also enhanced by PDBu, and it was attenuated by the PKC inhibitor Goe 6983. Forskolin-induced accumulation of cAMP in olfactory tissue was potentiated by carbachol, serotonin, and PDBu to a similar extent. Potentiation was completely suppressed by the PKC inhibitors Goe 6983, staurosporine, and polymyxin B, suggesting that the sensitivity of olfactory AC to stimulation by odorants and forskolin was increased by PKC. Experiments with deciliated olfactory tissue indicated that sensitization of AC was restricted to sensory cilia of ORCs. To study the effects of cell Ca2+ on these mechanisms, the intracellular Ca2+ concentration of olfactory tissue was either increased by ionomycin or decreased by BAPTA/AM. Increasing cell Ca2+ had two effects on cAMP production: (a) the basal cAMP production was enhanced by a mechanism sensitive to inhibitors of calmodulin; and (b) similar to phorbol ester, cell Ca2+ caused sensitization of AC to stimulation by forskolin, an effect sensitive to Goe 6983. Decreasing cell Ca2+ below basal levels rendered AC unresponsive to stimulation by forskolin. These data suggest that a crosstalk mechanism is functional in frog ORCs, linking the sensitivity of AC to the activity of PKC. At increased activity of PKC, olfactory AC becomes more responsive to stimulation by odorants, forskolin, and cell Ca2+. Neurotransmitters appear to use this crosstalk mechanism to regulate olfactory

  15. Glutamate Receptor Antagonist Infusions into the Basolateral and Medial Amygdala Reveal Differential Contributions to Olfactory vs. Context Fear Conditioning and Expression

    ERIC Educational Resources Information Center

    Walker, David L.; Paschall, Gayla Y.; Davis, Michael

    2005-01-01

    The basolateral amygdala's involvement in fear acquisition and expression to visual and auditory stimuli is well known. The involvement of the basolateral and other amygdala areas in fear acquisition and expression to stimuli of other modalities is less certain. We evaluated the contribution of the basolateral and medial amygdala to olfactory and…

  16. Identification of the western tarnished plant bug (lygus hesperus) olfactory co-receptor orco: expression profile and confirmation of atypical membrane topology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lygus hesperus (western tarnished plant bug) is an agronomically important pest species of numerous cropping systems. Similar to other insects, a critical component underlying behaviors is the perception and discrimination of olfactory cues. Consequently, the molecular basis of olfaction in this spe...

  17. Development of olfactory projection neuron dendrites that contribute to wiring specificity of the Drosophila olfactory circuit.

    PubMed

    Sakuma, Chisako; Anzo, Marie; Miura, Masayuki; Chihara, Takahiro

    2014-01-01

    The antennal lobe (AL) of Drosophila is the first olfactory processing center in which olfactory input and output are spatially organized into distinct channels via glomeruli to form a discrete neural map. In each glomerulus, the axons of a single type of olfactory receptor neurons (ORNs) synapse with the dendrites of a single type of projection neurons (PNs). The AL is an ideal place to study how the wiring specificity between specific types of ORNs and PNs is established during development. During the past two decades, the involvement of diverse molecules in the specification and patterning of ORNs and PNs has been reported. Furthermore, local interneurons-another component of glomeruli-have been recently catalogued and their functions have been gradually dissected. Although there is accumulating knowledge about the involvement of these three cell types in the wiring specificity of the olfactory system, in this review, we focus especially on the development of PN dendrites.

  18. Disruption of centrifugal inhibition to olfactory bulb granule cells impairs olfactory discrimination

    PubMed Central

    Nunez-Parra, Alexia; Maurer, Robert K.; Krahe, Krista; Smith, Richard S.; Araneda, Ricardo C.

    2013-01-01

    Granule cells (GCs) are the most abundant inhibitory neuronal type in the olfactory bulb and play a critical role in olfactory processing. GCs regulate the activity of principal neurons, the mitral cells, through dendrodendritic synapses, shaping the olfactory bulb output to other brain regions. GC excitability is regulated precisely by intrinsic and extrinsic inputs, and this regulation is fundamental for odor discrimination. Here, we used channelrhodopsin to stimulate GABAergic axons from the basal forebrain selectively and show that this stimulation generates reliable inhibitory responses in GCs. Furthermore, selective in vivo inhibition of GABAergic neurons in the basal forebrain by targeted expression of designer receptors exclusively activated by designer drugs produced a reversible impairment in the discrimination of structurally similar odors, indicating an important role of these inhibitory afferents in olfactory processing. PMID:23959889

  19. Structure and function of long-lived olfactory organotypic cultures from postnatal mice.

    PubMed

    Josephson, E M; Yilma, S; Vodyanoy, V; Morrison, E E

    2004-03-01

    The first synapse in the olfactory pathway mediates a significant transfer of information given the restricted association of specific olfactory receptor neurons with specific glomeruli in the olfactory bulb. To understand better how this connection is made and what the functional capacities of the participating cells are, we created a long-lived culture system composed of olfactory epithelium and olfactory bulb tissues. Using the roller tube method of culturing, we grew epithelium-bulb cocultures, explanted from 1-4-day-old Swiss Webster mice, on Aclar for periods ranging from 18 hr to 68 days. The explants flattened so that in some areas the culture was only a few cells thick, making individual cells distinguishable. From 107 cultures studied, we identified the following cell types by expression of specific markers (oldest culture expressing marker, days in vitro, DIV): olfactory receptor neurons (neural cell adhesion molecule, 42 DIV); mature receptor neurons (olfactory marker protein, 28 DIV); postmitotic olfactory receptor neurons and olfactory bulb neurons (beta-tubulin, 68 DIV); astrocytes (glial fibrillary acidic protein, glutamate/aspartate transporter, 68 DIV); olfactory horizontal basal cells (cytokeratin, 22 DIV). Neuronal processes formed glomeruli in 2-4-week-old cultures. We also recorded electro-olfactography responses to puffs of vapor collected over an odorant mixture containing ethyl butyrate, eugenol, (+) carvone, and (-) carvone from cultures as old as 21 DIV. These features of our olfactory culture system make this model useful for studying properties of immature and mature olfactory receptor neurons, pathfinding strategies of receptor axons, and mechanisms of information transfer in the olfactory glomerulus.

  20. A Screen for Genes Expressed in the Olfactory Organs of Drosophila melanogaster Identifies Genes Involved in Olfactory Behaviour

    PubMed Central

    Tunstall, Narelle E.; Herr, Anabel; de Bruyne, Marien; Warr, Coral G.

    2012-01-01

    Background For insects the sense of smell and associated olfactory-driven behaviours are essential for survival. Insects detect odorants with families of olfactory receptor proteins that are very different to those of mammals, and there are likely to be other unique genes and genetic pathways involved in the function and development of the insect olfactory system. Methodology/Principal Findings We have performed a genetic screen of a set of 505 Drosophila melanogaster gene trap insertion lines to identify novel genes expressed in the adult olfactory organs. We identified 16 lines with expression in the olfactory organs, many of which exhibited expression of the trapped genes in olfactory receptor neurons. Phenotypic analysis showed that six of the lines have decreased olfactory responses in a behavioural assay, and for one of these we showed that precise excision of the P element reverts the phenotype to wild type, confirming a role for the trapped gene in olfaction. To confirm the identity of the genes trapped in the lines we performed molecular analysis of some of the insertion sites. While for many lines the reported insertion sites were correct, we also demonstrated that for a number of lines the reported location of the element was incorrect, and in three lines there were in fact two pGT element insertions. Conclusions/Significance We identified 16 new genes expressed in the Drosophila olfactory organs, the majority in neurons, and for several of the gene trap lines demonstrated a defect in olfactory-driven behaviour. Further characterisation of these genes and their roles in olfactory system function and development will increase our understanding of how the insect olfactory system has evolved to perform the same essential function to that of mammals, but using very different molecular genetic mechanisms. PMID:22530061

  1. Organization of olfactory centres in the malaria mosquito Anopheles gambiae

    PubMed Central

    Riabinina, Olena; Task, Darya; Marr, Elizabeth; Lin, Chun-Chieh; Alford, Robert; O'Brochta, David A.; Potter, Christopher J.

    2016-01-01

    Mosquitoes are vectors for multiple infectious human diseases and use a variety of sensory cues (olfactory, temperature, humidity and visual) to locate a human host. A comprehensive understanding of the circuitry underlying sensory signalling in the mosquito brain is lacking. Here we used the Q-system of binary gene expression to develop transgenic lines of Anopheles gambiae in which olfactory receptor neurons expressing the odorant receptor co-receptor (Orco) gene are labelled with GFP. These neurons project from the antennae and maxillary palps to the antennal lobe (AL) and from the labella on the proboscis to the suboesophageal zone (SEZ), suggesting integration of olfactory and gustatory signals occurs in this brain region. We present detailed anatomical maps of olfactory innervations in the AL and the SEZ, identifying glomeruli that may respond to human body odours or carbon dioxide. Our results pave the way for anatomical and functional neurogenetic studies of sensory processing in mosquitoes. PMID:27694947

  2. Effects of disorder on properties of non-conventionally prepared barium titanate

    SciTech Connect

    Banerjee, A.; Sarkar, S.; Roychowdhury, A.; Das, D.

    2015-06-24

    Barium titanaten (BaTiO{sub 3}) nanoparticles were prepared by non-conventional as well as conventional solid state reaction. A better response about the grain size distribution was obtained in the former. The former was then milled to get grains of successive reduced sizes. The defects induced within the samples were studies by positron annihilation spectroscopy. The effect of defects on dielectric property of sample with finest grains was measured. Dielectric stability with temperature was increased with decreasing grain size and the peak was shifted towards the lower value due to the enhancement of grain boundary defects generated due to milling for long time.

  3. Olfactory dysfunction: its early temporal relationship and neural correlates in the pathogenesis of Alzheimer's disease.

    PubMed

    Daulatzai, Mak Adam

    2015-10-01

    We interact with the physical world through our senses, and these aid our behavioral performance and various activities of life. Sensory information is transmitted in neuronal networks, and the brain optimally interprets the external and internal milieu/environment. This paper delineates the framework in which the pathogenesis of memory and cognitive dysfunction is underpinned by sensory olfactory dysfunction. ERC is the gateway for olfactory input to the hippocampus, and there is seamless synchronization between sensory function and hippocampal activity. Transmission of olfactory information to the hippocampus is sequential-it is projected from the olfactory receptors to olfactory bulb to the primary olfactory cortex (comprised the anterior olfactory nucleus, the olfactory tubercle, and the piriform cortex) to the entorhinal cortex (ERC). Through perforant pathway ERC enables olfactory inputs to effectively excite hippocampal neurons. One of the earliest pathological changes in Alzheimer's disease (AD) include the olfactory dysfunction and the atrophy in ERC and hippocampus (rate in ERC is higher than in the hippocampus). Olfactory dysfunction negatively impacts the ERC and the deafferenting of the hippocampus from olfactory inputs upregulates memory decline. Olfactory dysfunction, therefore, is an important and early correlate of AD pathology. A number of factors described here may cause olfactory dysfunction; this may lead to hypoperfusion, hypometabolism, impaired synaptic transmission, and variable atrophy in olfaction-related regions. Improvement in olfactory function, therefore, is an important goal in order to attenuate cognitive neuropathology in aging and AD. This article seeks to provide a comprehensive and balanced overview of olfactory neuropathology in incipient AD, and suggests strategies to enhance olfactory function and ameliorate cognitive decline. PMID:25944089

  4. Evolving olfactory systems on the fly.

    PubMed

    Ramdya, Pavan; Benton, Richard

    2010-07-01

    The detection of odour stimuli in the environment is universally important for primal behaviours such as feeding, mating, kin interactions and escape responses. Given the ubiquity of many airborne chemical signals and the similar organisation of animal olfactory circuits, a fundamental question in our understanding of the sense of smell is how species-specific behavioural responses to odorants can evolve. Recent comparative genomic, developmental and physiological studies are shedding light on this problem by providing insights into the genetic mechanisms that underlie anatomical and functional evolution of the olfactory system. Here we synthesise these data, with a particular focus on insect olfaction, to address how new olfactory receptors and circuits might arise and diverge, offering glimpses into how odour-evoked behaviours could adapt to an ever-changing chemosensory world.

  5. Electronic structures of topological insulator Bi2Te3 surfaces with non-conventional terminations

    NASA Astrophysics Data System (ADS)

    Zhu, Xie-Gang; Zhang, Yun; Feng, Wei; Yuan, Bing-Kai; Liu, Qin; Qiu, Rui-Zhi; Xie, Dong-Hua; Tan, Shi-Yong; Duan, Yu; Fang, Yun; Zhang, Wen; Lai, Xin-Chun

    2016-09-01

    Topological insulators (TIs) are theoretically believed to possess robust surface states (SSs) for any surface terminations. In reality, for TIs with non-conventional terminations, the directly experimental demonstration of this argument is somehow hindered, due to the difficulties in sample preparation and lack of efficient electronic structure characterization method. Here, by using the state-of-the-art molecular beam epitaxy, we manage to prepare TI Bi2Te3 thin film with non-conventional fractional quintuple layer (FQL) termination. Scanning tunneling microscopy reveals that the as-grown Bi2Te3 thin film may not necessarily terminate at the van der Waals gap between two adjacent quintuple layers. The electronic structures of the FQL termination are studied in combination with quasi-particle interference pattern by scanning tunneling spectroscopy and SS calculations by tight binding method. Our results suggest that the topological nature of SSs be preserved on various terminations. Possible ways of achieving exotic topological SSs are also discussed.

  6. Thermal control of a lidar laser system using a non-conventional ram air heat exchanger

    NASA Technical Reports Server (NTRS)

    Killough, Brian D.; Alexander, William, Jr.; Swofford, Doyle P.

    1990-01-01

    This paper describes the analysis and performance testing of a uniquely designed external heat exchanger. The heat exchanger is attached externally to an aircraft and is used to cool a laser system within the fuselage. Estimates showed insufficient cooling capacity with a conventional staggered tube array in the limited space available. Thus, a non-conventional design wes developed with larger tube and fin area exposed to the ram air to increase the heat transfer performance. The basic design consists of 28 circular finned aluminum tubes arranged in two parallel banks. Wind tunnel tests were performed to simulate air and liquid flight conditions for the non-conventional parallel bank arrangement and the conventional staggered tube arrangement. Performance comparisons of each of the two designs are presented. Test results are used in a computer model of the heat exchanger to predict the operating performance for the entire flight profile. These analyses predict significantly improved performance over the conventional design and show adequate thermal control margins.

  7. Thermal control of a lidar laser system using a non-conventional ram air heat exchanger

    NASA Astrophysics Data System (ADS)

    Killough, Brian D.; Alexander, William, Jr.; Swofford, Doyle P.

    1990-10-01

    This paper describes the analysis and performance testing of a uniquely designed external heat exchanger. The heat exchanger is attached externally to an aircraft and is used to cool a laser system within the fuselage. Estimates showed insufficient cooling capacity with a conventional staggered tube array in the limited space available. Thus, a non-conventional design wes developed with larger tube and fin area exposed to the ram air to increase the heat transfer performance. The basic design consists of 28 circular finned aluminum tubes arranged in two parallel banks. Wind tunnel tests were performed to simulate air and liquid flight conditions for the non-conventional parallel bank arrangement and the conventional staggered tube arrangement. Performance comparisons of each of the two designs are presented. Test results are used in a computer model of the heat exchanger to predict the operating performance for the entire flight profile. These analyses predict significantly improved performance over the conventional design and show adequate thermal control margins.

  8. Carbohydrate and energy-yielding metabolism in non-conventional yeasts.

    PubMed

    Flores, C L; Rodríguez, C; Petit, T; Gancedo, C

    2000-10-01

    Sugars are excellent carbon sources for all yeasts. Since a vast amount of information is available on the components of the pathways of sugar utilization in Saccharomyces cerevisiae it has been tacitly assumed that other yeasts use sugars in the same way. However, although the pathways of sugar utilization follow the same theme in all yeasts, important biochemical and genetic variations on it exist. Basically, in most non-conventional yeasts, in contrast to S. cerevisiae, respiration in the presence of oxygen is prominent for the use of sugars. This review provides comparative information on the different steps of the fundamental pathways of sugar utilization in non-conventional yeasts: glycolysis, fermentation, tricarboxylic acid cycle, pentose phosphate pathway and respiration. We consider also gluconeogenesis and, briefly, catabolite repression. We have centered our attention in the genera Kluyveromyces, Candida, Pichia, Yarrowia and Schizosaccharomyces, although occasional reference to other genera is made. The review shows that basic knowledge is missing on many components of these pathways and also that studies on regulation of critical steps are scarce. Information on these points would be important to generate genetically engineered yeast strains for certain industrial uses.

  9. Unrest in Utopia: Israeli patients' dissatisfaction with non-conventional medicine.

    PubMed

    Fadlon, Judith

    2004-06-01

    In recent years, non-conventional medicine (NCM) has grown tremendously in popularity and economic importance. This paper explores a relatively unresearched phenomenon: patients' dissatisfaction with non-conventional medical treatment they have received. 16 out of 20 patients who had severed their contact with a large, hospital-adjacent multi-modality NCM clinic in Israel were interviewed. Two of these patients had severed their relationship with the clinic right after being referred to a certain practitioner and 18 did not keep their next appointment while in the process of treatment. The narratives through which participants understand and communicate their experience regarding dissatisfaction with NCM are organized around three main topics: independence versus paternalism, foreign versus familiar, and care versus cure. Findings illustrate the patients' views concerning the desirable doctor-patient relationship and their expectations of non-familiar treatments. Patients are characterized as "smart consumers" who place utmost importance on outcome and do not hesitate to discontinue treatment. Findings are further discussed in the context of domestication and the minimizing of cultural difference through the integration of NCM into a biomedical setting.

  10. Odorant concentration differentiator for intermittent olfactory signals.

    PubMed

    Fujiwara, Terufumi; Kazawa, Tomoki; Sakurai, Takeshi; Fukushima, Ryota; Uchino, Keiro; Yamagata, Tomoko; Namiki, Shigehiro; Haupt, Stephan Shuichi; Kanzaki, Ryohei

    2014-12-10

    Animals need to discriminate differences in spatiotemporally distributed sensory signals in terms of quality as well as quantity for generating adaptive behavior. Olfactory signals characterized by odor identity and concentration are intermittently distributed in the environment. From these intervals of stimulation, animals process odorant concentration to localize partners or food sources. Although concentration-response characteristics in olfactory neurons have traditionally been investigated using single stimulus pulses, their behavior under intermittent stimulus regimens remains largely elusive. Using the silkmoth (Bombyx mori) pheromone processing system, a simple and behaviorally well-defined model for olfaction, we investigated the neuronal representation of odorant concentration upon intermittent stimulation in the naturally occurring range. To the first stimulus in a series, the responses of antennal lobe (AL) projection neurons (PNs) showed a concentration dependence as previously shown in many olfactory systems. However, PN response amplitudes dynamically changed upon exposure to intermittent stimuli of the same odorant concentration and settled to a constant, largely concentration-independent level. As a result, PN responses emphasized odorant concentration changes rather than encoding absolute concentration in pulse trains of stimuli. Olfactory receptor neurons did not contribute to this response transformation which was due to long-lasting inhibition affecting PNs in the AL. Simulations confirmed that inhibition also provides advantages when stimuli have naturalistic properties. The primary olfactory center thus functions as an odorant concentration differentiator to efficiently detect concentration changes, thereby improving odorant source orientation over a wide concentration range.

  11. Olfactory signal coding in an odor background.

    PubMed

    Renou, Michel; Party, Virginie; Rouyar, Angéla; Anton, Sylvia

    2015-10-01

    Insects communicating with pheromones are confronted with an olfactory environment featuring a diversity of volatile organic compounds from plant origin. These volatiles constitute a rich and fluctuant background from which the information carried by the pheromone signal must be extracted. Thus, the pheromone receptor neurons must encode into spike trains the quality, intensity and temporal characteristics of the signal that are determinant to the recognition and localization of a conspecific female. We recorded and analyzed the responses of the pheromone olfactory receptor neurons of male moths to sex pheromone in different odor background conditions. We show that in spite of the narrow chemical tuning of the pheromone receptor neurons, the sensory input can be altered by odorant background. PMID:26116090

  12. Identification of G protein α subunits in the main olfactory system and vomeronasal system of the Japanese Striped snake, Elaphe quadrivirgata.

    PubMed

    Kondoh, Daisuke; Koshi, Katsuo; Ono, Hisaya K; Sasaki, Kuniaki; Nakamuta, Nobuaki; Taniguchi, Kazuyuki

    2013-01-01

    In the olfactory system, G proteins couple to the olfactory receptors, and G proteins expressed in the main olfactory system and vomeronasal system vary according to animal species. In this study, G protein α subunits expressed in the main olfactory system and vomeronasal system of the snake were identified by immunohistochemistry. In the olfactory epithelium, only anti-Gαolf/s antibody labeled the cilia of the receptor cells. In the vomeronasal epithelium, only anti-Gαo antibody labeled the microvilli of the receptor cells. In the accessory olfactory bulb, anti-Gαo antibody stained the whole glomerular layer. These results suggest that the main olfactory system and the vomeronasal system of the snake express Gαolf and Gαo as G proteins coupling to the olfactory receptors, respectively.

  13. CD36 is involved in oleic acid detection by the murine olfactory system.

    PubMed

    Oberland, Sonja; Ackels, Tobias; Gaab, Stefanie; Pelz, Thomas; Spehr, Jennifer; Spehr, Marc; Neuhaus, Eva M

    2015-01-01

    Olfactory signals influence food intake in a variety of species. To maximize the chances of finding a source of calories, an animal's preference for fatty foods and triglycerides already becomes apparent during olfactory food search behavior. However, the molecular identity of both receptors and ligands mediating olfactory-dependent fatty acid recognition are, so far, undescribed. We here describe that a subset of olfactory sensory neurons expresses the fatty acid receptor CD36 and demonstrate a receptor-like localization of CD36 in olfactory cilia by STED microscopy. CD36-positive olfactory neurons share olfaction-specific transduction elements and project to numerous glomeruli in the ventral olfactory bulb. In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca(2+) imaging experiments is drastically reduced in young CD36 knock-out mice. Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period. Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system. PMID:26441537

  14. CD36 is involved in oleic acid detection by the murine olfactory system

    PubMed Central

    Oberland, Sonja; Ackels, Tobias; Gaab, Stefanie; Pelz, Thomas; Spehr, Jennifer; Spehr, Marc; Neuhaus, Eva M.

    2015-01-01

    Olfactory signals influence food intake in a variety of species. To maximize the chances of finding a source of calories, an animal’s preference for fatty foods and triglycerides already becomes apparent during olfactory food search behavior. However, the molecular identity of both receptors and ligands mediating olfactory-dependent fatty acid recognition are, so far, undescribed. We here describe that a subset of olfactory sensory neurons expresses the fatty acid receptor CD36 and demonstrate a receptor-like localization of CD36 in olfactory cilia by STED microscopy. CD36-positive olfactory neurons share olfaction-specific transduction elements and project to numerous glomeruli in the ventral olfactory bulb. In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca2+ imaging experiments is drastically reduced in young CD36 knock-out mice. Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period. Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system. PMID:26441537

  15. Odorant metabolism catalyzed by olfactory mucosal enzymes influences peripheral olfactory responses in rats.

    PubMed

    Thiebaud, Nicolas; Veloso Da Silva, Stéphanie; Jakob, Ingrid; Sicard, Gilles; Chevalier, Joëlle; Ménétrier, Franck; Berdeaux, Olivier; Artur, Yves; Heydel, Jean-Marie; Le Bon, Anne-Marie

    2013-01-01

    A large set of xenobiotic-metabolizing enzymes (XMEs), such as the cytochrome P450 monooxygenases (CYPs), esterases and transferases, are highly expressed in mammalian olfactory mucosa (OM). These enzymes are known to catalyze the biotransformation of exogenous compounds to facilitate elimination. However, the functions of these enzymes in the olfactory epithelium are not clearly understood. In addition to protecting against inhaled toxic compounds, these enzymes could also metabolize odorant molecules, and thus modify their stimulating properties or inactivate them. In the present study, we investigated the in vitro biotransformation of odorant molecules in the rat OM and assessed the impact of this metabolism on peripheral olfactory responses. Rat OM was found to efficiently metabolize quinoline, coumarin and isoamyl acetate. Quinoline and coumarin are metabolized by CYPs whereas isoamyl acetate is hydrolyzed by carboxylesterases. Electro-olfactogram (EOG) recordings revealed that the hydroxylated metabolites derived from these odorants elicited lower olfactory response amplitudes than the parent molecules. We also observed that glucurono-conjugated derivatives induced no olfactory signal. Furthermore, we demonstrated that the local application of a CYP inhibitor on rat olfactory epithelium increased EOG responses elicited by quinoline and coumarin. Similarly, the application of a carboxylesterase inhibitor increased the EOG response elicited by isoamyl acetate. This increase in EOG amplitude provoked by XME inhibitors is likely due to enhanced olfactory sensory neuron activation in response to odorant accumulation. Taken together, these findings strongly suggest that biotransformation of odorant molecules by enzymes localized to the olfactory mucosa may change the odorant's stimulating properties and may facilitate the clearance of odorants to avoid receptor saturation. PMID:23555703

  16. Expression of Olfactory Signaling Genes in the Eye

    PubMed Central

    Velmeshev, Dmitry; Faghihi, Mohammad; Shestopalov, Valery I.; Slepak, Vladlen Z.

    2014-01-01

    Purpose To advance our understanding how the outer eye interacts with its environment, we asked which cellular receptors are expressed in the cornea, focusing on G protein-coupled receptors. Methods Total RNA from the mouse cornea was subjected to next-generation sequencing using the Illumina platform. The data was analyzed with TopHat and CuffLinks software packages. Expression of a representative group of genes detected by RNA-seq was further analyzed by RT-PCR and in situ hybridization using RNAscope technology and fluorescent microscopy. Results We generated more than 46 million pair-end reads from mouse corneal RNA. Bioinformatics analysis revealed that the mouse corneal transcriptome reconstructed from these reads represents over 10,000 gene transcripts. We identified 194 GPCR transcripts, of which 96 were putative olfactory receptors. RT-PCR analysis confirmed the presence of several olfactory receptors and related genes, including olfactory marker protein and the G protein associated with olfaction, Gαolf. In situ hybridization showed that mRNA for olfactory marker protein, Gαolf and possibly some olfactory receptors were found in the corneal epithelial cells. In addition to the corneal epithelium, Gαolf was present in the ganglionic and inner nuclear layers of the retina. One of the olfactory receptors, Olfr558, was present primarily in vessels of the eye co-stained with antibodies against alpha-smooth muscle actin, indicating expression in arterioles. Conclusions Several species of mRNA encoding putative olfactory receptors and related genes are expressed in the mouse cornea and other parts of the eye indicating they may play a role in sensing chemicals in the ocular environment. PMID:24789354

  17. Construction of odor representations by olfactory bulb microcircuits.

    PubMed

    Cleland, Thomas A

    2014-01-01

    Like other sensory systems, the olfactory system transduces specific features of the external environment and must construct an organized sensory representation from these highly fragmented inputs. As with these other systems, this representation is not accurate per se, but is constructed for utility, and emphasizes certain, presumably useful, features over others. I here describe the cellular and circuit mechanisms of the peripheral olfactory system that underlie this process of sensory construction, emphasizing the distinct architectures and properties of the two prominent computational layers in the olfactory bulb. Notably, while the olfactory system solves essentially similar conceptual problems to other sensory systems, such as contrast enhancement, activity normalization, and extending dynamic range, its peculiarities often require qualitatively different computational algorithms than are deployed in other sensory modalities. In particular, the olfactory modality is intrinsically high dimensional, and lacks a simple, externally defined basis analogous to wavelength or pitch on which elemental odor stimuli can be quantitatively compared. Accordingly, the quantitative similarities of the receptive fields of different odorant receptors (ORs) vary according to the statistics of the odor environment. To resolve these unusual challenges, the olfactory bulb appears to utilize unique nontopographical computations and intrinsic learning mechanisms to perform the necessary high-dimensional, similarity-dependent computations. In sum, the early olfactory system implements a coordinated set of early sensory transformations directly analogous to those in other sensory systems, but accomplishes these with unique circuit architectures adapted to the properties of the olfactory modality.

  18. Integrating temperature with odor processing in the olfactory bulb.

    PubMed

    Kludt, Eugen; Okom, Camille; Brinkmann, Alexander; Schild, Detlev

    2015-05-20

    Temperature perception has long been classified as a somesthetic function solely. However, in recent years several studies brought evidence that temperature perception also takes place in the olfactory system of rodents. Temperature has been described as an effective stimulus for sensory neurons of the Grueneberg ganglion located at the entrance of the nose. Here, we investigate whether a neuronal trace of temperature stimulation can be observed in the glomeruli and mitral cells of the olfactory bulb, using calcium imaging and fast line-scanning microscopy. We show in the Xenopus tadpole system that the γ-glomerulus, which receives input from olfactory neurons, is highly sensitive to temperature drops at the olfactory epithelium. We observed that thermo-induced activity in the γ-glomerulus is conveyed to the mitral cells innervating this specific neuropil. Surprisingly, a substantial number of thermosensitive mitral cells were also chemosensitive. Moreover, we report another unique feature of the γ-glomerulus: it receives ipsilateral and contralateral afferents. The latter fibers pass through the contralateral bulb, cross the anterior commissure, and then run to the ipsilateral olfactory bulb, where they target the γ-glomerulus. Temperature drops at the contralateral olfactory epithelium also induced responses in the γ-glomerulus and in mitral cells. Temperature thus appears to be a relevant physiological input to the Xenopus olfactory system. Each olfactory bulb integrates and codes temperature signals originating from receptor neurons of the ipsilateral and contralateral nasal cavities. Finally, temperature and chemical information is processed in shared cellular networks.

  19. Histological and lectin histochemical studies on the olfactory mucosae of the Korean roe deer, Capreolus pygargus.

    PubMed

    Park, Changnam; Ahn, Meejung; Kim, Jeongtae; Kim, Seungjoon; Moon, Changjong; Shin, Taekyun

    2015-04-01

    The morphological features of the olfactory mucosae of Korean roe deer, Capreolus pygargus, were histologically studied using the ethmoid turbinates containing the olfactory mucosae from six roe deer (male, 2-3 years old). The ethmoid turbinates were embedded in paraffin, and histochemically evaluated in terms of the mucosal characteristics. Lectin histochemistry was performed to investigate the carbohydrate-binding specificity on the olfactory mucosa. Lectins, including Triticum vulgaris wheat germ agglutinin (WGA), Ulex europaeus agglutinin I (UEA-I), and soybean agglutinin (SBA) were used for the N-acetylglucosamine, fucose and N-acetylgalactosamine carbohydrate groups, respectively. Histologically, the olfactory mucosa, positioned mainly in the caudal roof of the nasal cavity, consisted of the olfactory epithelium and the lamina propria. The olfactory epithelium consisted of protein gene product (PGP) 9.5-positive olfactory receptor cells, galectin-3-positive supporting cells and basal cells. Bowman's glands in the lamina propria were stained by both the periodic acid Schiff reagent and alcian blue (pH 2.5). Two types of lectin, WGA and SBA, were labeled in free border, receptor cells, supporting cells and Bowman's glands, with the exception of basal cells, while UEA-I was labeled in free border, supporting cells and Bowman's glands, but not in receptor cells and basal cells, suggesting that carbohydrate terminals on the olfactory mucosae of roe deer vary depending on cell type. This is the first morphological study of the olfactory mucosa of the Korean roe deer to evaluate carbohydrate terminals in the olfactory mucosae.

  20. Spatial variation in response to odorants on the rat olfactory epithelium.

    PubMed

    Edwards, D A; Mather, R A; Dodd, G H

    1988-03-15

    We have measured the electro-olfactogram produced by four odorants, nicotine, i-pentyl acetate, i-pentanoic acid and cineole from twelve positions on an in vitro preparation of rat olfactory tissue. Each odorant shows a different pattern of response over the twelve positions which can be explained by differences in olfactory receptor populations between regions of the rat olfactory epithelium. The result for nicotine is further evidence that there are olfactory receptors which are stimulated by nicotine when it is presented as a vapour. PMID:3350129

  1. Opportunities for utilization of non-conventional energy sources for biomass pretreatment.

    PubMed

    Singh, Rawel; Krishna, Bhavya B; Kumar, Jitendra; Bhaskar, Thallada

    2016-01-01

    The increasing concerns over the depletion of fossil resources and its associated geo-political issues have driven the entire world to move toward sustainable forms of energy. Pretreatment is the first step in any biochemical conversion process for the production of valuable fuels/chemicals from lignocellulosic biomass to eliminate the lignin and produce fermentable sugars by hydrolysis. Conventional techniques have several limitations which can be addressed by using them in tandem with non-conventional methods for biomass pretreatment. Electron beam and γ (gamma)-irradiation, microwave and ultrasound energies have certain advantages over conventional source of energy and there is an opportunity that these energies can be exploited for biomass pretreatment. PMID:26350883

  2. Opportunities for utilization of non-conventional energy sources for biomass pretreatment.

    PubMed

    Singh, Rawel; Krishna, Bhavya B; Kumar, Jitendra; Bhaskar, Thallada

    2016-01-01

    The increasing concerns over the depletion of fossil resources and its associated geo-political issues have driven the entire world to move toward sustainable forms of energy. Pretreatment is the first step in any biochemical conversion process for the production of valuable fuels/chemicals from lignocellulosic biomass to eliminate the lignin and produce fermentable sugars by hydrolysis. Conventional techniques have several limitations which can be addressed by using them in tandem with non-conventional methods for biomass pretreatment. Electron beam and γ (gamma)-irradiation, microwave and ultrasound energies have certain advantages over conventional source of energy and there is an opportunity that these energies can be exploited for biomass pretreatment.

  3. Non-Conventional Applications of Computerized Tomography: Analysis of Solid Dosage Forms Produced by Pharmaceutical Industry

    SciTech Connect

    Martins de Oliveira, Jose Jr.; Germano Martins, Antonio Cesar

    2010-05-21

    X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe a non-conventional application of computerized tomography: visualization and improvements in the understanding of some internal structural features of solid dosage forms. A micro-CT X-ray scanner, with a minimum resolution of 30 mum was used to characterize some pharmaceutical tablets, granules, controlled-release osmotic tablet and liquid-filled soft-gelatin capsules. The analysis presented in this work are essentially qualitative, but quantitative parameters, such as porosity, density distribution, tablets dimensions, etc. could also be obtained using the related CT techniques.

  4. Ratcheting Behavior of a Non-conventional Stainless Steel and Associated Microstructural Variations

    NASA Astrophysics Data System (ADS)

    Sahu, Lopamudra; Mishra, Awanish Kumar; Dutta, Krishna

    2014-11-01

    Ratcheting fatigue behavior of a non-conventional stainless steel X12CrMnNiN17-7-5 has been investigated with varying combinations of mean stress (σm) and stress amplitude (σa) at room temperature using a servo-hydraulic universal testing machine. X-ray diffraction profile analysis has been carried out for assessing possible martensitic phase transformation in the steel subjected to ratcheting deformation. The results indicate that ratcheting strain as well as volume fraction of martensite increases with increasing σm and/or σa; the phenomenon of strain accumulation is considered to be governed by the associated mechanics of cyclic loading, increased plastic damage as well as martensitic transformation. A correlation between strain produced by ratcheting deformation and martensitic transformation has been established.

  5. Ratcheting Behavior of a Non-conventional Stainless Steel and Associated Microstructural Variations

    NASA Astrophysics Data System (ADS)

    Sahu, Lopamudra; Mishra, Awanish Kumar; Dutta, Krishna

    2014-09-01

    Ratcheting fatigue behavior of a non-conventional stainless steel X12CrMnNiN17-7-5 has been investigated with varying combinations of mean stress (σm) and stress amplitude (σa) at room temperature using a servo-hydraulic universal testing machine. X-ray diffraction profile analysis has been carried out for assessing possible martensitic phase transformation in the steel subjected to ratcheting deformation. The results indicate that ratcheting strain as well as volume fraction of martensite increases with increasing σm and/or σa; the phenomenon of strain accumulation is considered to be governed by the associated mechanics of cyclic loading, increased plastic damage as well as martensitic transformation. A correlation between strain produced by ratcheting deformation and martensitic transformation has been established.

  6. Nutritional value of some non-conventional plant foods of India.

    PubMed

    Duhan, A; Chauhan, B M; Punia, D

    1992-07-01

    Thirteen non-conventional foods including fruits, leaves and grains consumed in various parts of the Indian subcontinent were analysed for their nutritional value. Khejri beans (Prsopsis cineria), Pinju (Capparis decidua) and Kachri (Cucumis species) contained considerable amounts of protein (15-18%). Kachri was rich in fat (13%). Bhakri (Tribulus terristris), Gullar (Ficus glomerata) and Peehl (Salvadora oleoides) were found to be rich sources of calcium; Gullar contained about 15 times the amount of calcium present in wheat. Phosphorus content of Santhi (Boernavia diffusa), Khejri beans, Bhakri, Pinju and Lehsora (Cordia dichotoma) were noticeable. Zinc was present in high amounts in Peepalbanti (Ficus religiosa) and Gullar; as was iron in Santhi and Bhakri and manganese in Santhi. Besides iron, zinc and calcium, Pinju contained appreciable amounts of beta-carotene and vitamin C. However, Santhi contained high amounts of oxalic acid.

  7. Synthetic biology and molecular genetics in non-conventional yeasts: Current tools and future advances.

    PubMed

    Wagner, James M; Alper, Hal S

    2016-04-01

    Coupling the tools of synthetic biology with traditional molecular genetic techniques can enable the rapid prototyping and optimization of yeast strains. While the era of yeast synthetic biology began in the well-characterized model organism Saccharomyces cerevisiae, it is swiftly expanding to include non-conventional yeast production systems such as Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. These yeasts already have roles in the manufacture of vaccines, therapeutic proteins, food additives, and biorenewable chemicals, but recent synthetic biology advances have the potential to greatly expand and diversify their impact on biotechnology. In this review, we summarize the development of synthetic biological tools (including promoters and terminators) and enabling molecular genetics approaches that have been applied in these four promising alternative biomanufacturing platforms. An emphasis is placed on synthetic parts and genome editing tools. Finally, we discuss examples of synthetic tools developed in other organisms that can be adapted or optimized for these hosts in the near future.

  8. Acid sensing by the Drosophila olfactory system.

    PubMed

    Ai, Minrong; Min, Soohong; Grosjean, Yael; Leblanc, Charlotte; Bell, Rati; Benton, Richard; Suh, Greg S B

    2010-12-01

    The odour of acids has a distinct quality that is perceived as sharp, pungent and often irritating. How acidity is sensed and translated into an appropriate behavioural response is poorly understood. Here we describe a functionally segregated population of olfactory sensory neurons in the fruitfly, Drosophila melanogaster, that are highly selective for acidity. These olfactory sensory neurons express IR64a, a member of the recently identified ionotropic receptor (IR) family of putative olfactory receptors. In vivo calcium imaging showed that IR64a+ neurons projecting to the DC4 glomerulus in the antennal lobe are specifically activated by acids. Flies in which the function of IR64a+ neurons or the IR64a gene is disrupted had defects in acid-evoked physiological and behavioural responses, but their responses to non-acidic odorants remained unaffected. Furthermore, artificial stimulation of IR64a+ neurons elicited avoidance responses. Taken together, these results identify cellular and molecular substrates for acid detection in the Drosophila olfactory system and support a labelled-line mode of acidity coding at the periphery. PMID:21085119

  9. miRepress: modelling gene expression regulation by microRNA with non-conventional binding sites

    PubMed Central

    Ghosal, Suman; Saha, Shekhar; Das, Shaoli; Sen, Rituparno; Goswami, Swagata; Jana, Siddhartha S.; Chakrabarti, Jayprokas

    2016-01-01

    Some earlier studies have reported an alternative mode of microRNA-target interaction. We detected target regions within mRNA transcripts from AGO PAR-CLIP that did not contain any conventional microRNA seed pairing but only had non-conventional binding sites with microRNA 3′ end. Our study from 7 set of data that measured global protein fold change after microRNA transfection pointed towards the association of target protein fold change with 6-mer and 7-mer target sites involving microRNA 3′ end. We developed a model to predict the degree of microRNA target regulation in terms of protein fold changes from the number of different conventional and non-conventional target sites present in the target, and found significant correlation of its output with protein expression changes. We validated the effect of non-conventional interactions with target by modulating the abundance of microRNA in a human breast cancer cell line MCF-7. The validation was done using luciferase assay and immunoblot analysis for our predicted non-conventional microRNA-target pair WNT1 (3′ UTR) and miR-367-5p and immunoblot analysis for another predicted non-conventional microRNA-target pair MYH10 (coding region) and miR-181a-5p. Both experiments showed inhibition of targets by transfection of microRNA mimics that were predicted to have only non-conventional sites. PMID:26923536

  10. The endocannabinoid system controls food intake via olfactory processes.

    PubMed

    Soria-Gómez, Edgar; Bellocchio, Luigi; Reguero, Leire; Lepousez, Gabriel; Martin, Claire; Bendahmane, Mounir; Ruehle, Sabine; Remmers, Floor; Desprez, Tifany; Matias, Isabelle; Wiesner, Theresa; Cannich, Astrid; Nissant, Antoine; Wadleigh, Aya; Pape, Hans-Christian; Chiarlone, Anna Paola; Quarta, Carmelo; Verrier, Daniéle; Vincent, Peggy; Massa, Federico; Lutz, Beat; Guzmán, Manuel; Gurden, Hirac; Ferreira, Guillaume; Lledo, Pierre-Marie; Grandes, Pedro; Marsicano, Giovanni

    2014-03-01

    Hunger arouses sensory perception, eventually leading to an increase in food intake, but the underlying mechanisms remain poorly understood. We found that cannabinoid type-1 (CB1) receptors promote food intake in fasted mice by increasing odor detection. CB1 receptors were abundantly expressed on axon terminals of centrifugal cortical glutamatergic neurons that project to inhibitory granule cells of the main olfactory bulb (MOB). Local pharmacological and genetic manipulations revealed that endocannabinoids and exogenous cannabinoids increased odor detection and food intake in fasted mice by decreasing excitatory drive from olfactory cortex areas to the MOB. Consistently, cannabinoid agonists dampened in vivo optogenetically stimulated excitatory transmission in the same circuit. Our data indicate that cortical feedback projections to the MOB crucially regulate food intake via CB1 receptor signaling, linking the feeling of hunger to stronger odor processing. Thus, CB1 receptor-dependent control of cortical feedback projections in olfactory circuits couples internal states to perception and behavior. PMID:24509429

  11. Concentration-invariant odor representation in the olfactory system by presynaptic inhibition.

    PubMed

    Zhang, Danke; Li, Yuanqing; Wu, Si

    2013-01-01

    The present study investigates a network model for implementing concentration-invariant representation for odors in the olfactory system. The network consists of olfactory receptor neurons, projection neurons, and inhibitory local neurons. Receptor neurons send excitatory inputs to projection neurons, which are modulated by the inhibitory inputs from local neurons. The modulation occurs at the presynaptic site from a receptor neuron to a projection one, leading to the operation of divisive normalization. The responses of local interneurons are determined by the total activities of olfactory receptor neurons. We find that with a proper parameter condition, the responses of projection neurons become effectively independent of the odor concentration. Simulation results confirm our theoretical analysis.

  12. Nasal toxicity, carcinogenicity, and olfactory uptake of metals.

    PubMed

    Sunderman, F W

    2001-01-01

    Occupational exposures to inhalation of certain metal dusts or aerosols can cause loss of olfactory acuity, atrophy of the nasal mucosa, mucosal ulcers, perforated nasal septum, or sinonasal cancer. Anosmia and hyposmia have been observed in workers exposed to Ni- or Cd-containing dusts in alkaline battery factories, nickel refineries, and cadmium industries. Ulcers of the nasal mucosa and perforated nasal septum have been reported in workers exposed to Cr(VI) in chromate production and chrome plating, or to As(III) in arsenic smelters. Atrophy of the olfactory epithelium has been observed in rodents following inhalation of NiSO4 or alphaNi3S2. Cancers of the nose and nasal sinuses have been reported in workers exposed to Ni compounds in nickel refining, cutlery factories, and alkaline battery manufacture, or to Cr(VI) in chromate production and chrome plating. In animals, several metals (eg, Al, Cd, Co, Hg, Mn, Ni, Zn) have been shown to pass via olfactory receptor neurons from the nasal lumen through the cribriform plate to the olfactory bulb. Some metals (eg, Mn, Ni, Zn) can cross synapses in the olfactory bulb and migrate via secondary olfactory neurons to distant nuclei of the brain. After nasal instillation of a metal-containing solution, transport of the metal via olfactory axons can occur rapidly, within hours or a few days (eg, Mn), or slowly over days or weeks (eg, Ni). The olfactory bulb tends to accumulate certain metals (eg, Al, Bi, Cu, Mn, Zn) with greater avidity than other regions of the brain. The molecular mechanisms responsible for metal translocation in olfactory neurons and deposition in the olfactory bulb are unclear, but complexation by metal-binding molecules such as carnosine (beta-alanyl-L-histidine) may be involved. PMID:11314863

  13. The olfactory bulb structure of African giant rat (Cricetomys gambianus, Waterhouse 1840) I: cytoarchitecture.

    PubMed

    Olude, M A; Ogunbunmi, T K; Olopade, J O; Ihunwo, A O

    2014-09-01

    The olfactory system typically consists of two parallel systems: the main olfactory system and the accessory olfactory system. The main olfactory bulb (MOB) acts as the initial processing site for volatile chemical stimuli and receives input from the olfactory receptor cells located in the olfactory epithelium. The African giant rat is reputed to have abilities to detect landmines and tuberculosis samples by sniffing. This study therefore is a preliminary study on the histological and immunohistochemical anatomy of the olfactory bulb of the African giant rat (Cricetomys gambianus, Waterhouse). Nissl and Klüver-Barrera histological staining of the olfactory bulb revealed a cytoarchitecture typical of most mammals with 6 cell layers, and 1-2-layered glomeruli measuring approximately 150 μm each in diameter. Immunohistochemical staining with glial fibrillary acidic protein (GFAP) and 2',3'-cyclic nucleotide 3-phosphodiesterase (CNPase) revealed cellular conformations relative to most mammals. GFAP immunohistochemistry also revealed cell bodies and processes within the periglomerular area which may potentiate signaling from the olfactory receptor cells, while CNPase largely showed soma and evidence of myelin sheath deposition, confirming myelination at different layers of the bulb. Neurogenesis was examined using the neurogenic markers doublecortin (DCX) and Ki-67. Migration of newly generated cells was observed in all layers of the MOB with DCX and in most layers with Ki-67. The anatomy of the olfactory bulb is described as relatively large in the African giant rat, having a neuroarchitecture similar to most rodents.

  14. Endocrine Modulation of Olfactory Responsiveness: Effects of the Orexigenic Hormone Ghrelin.

    PubMed

    Loch, Diana; Breer, Heinz; Strotmann, Jörg

    2015-09-01

    Finding food sources is a prerequisite for an acute food intake. This process is initiated by ghrelin released from X/A-like cells of the gastrointestinal tract. Because food finding often depends on olfaction, the question arises whether ghrelin may affect the responsiveness of the olfactory system. Monitoring odor-induced activation of the mouse olfactory epithelium via Egr1 expression revealed that after a nasal application of ghrelin, more sensory neurons responded upon odor exposure indicating an increased responsiveness. The higher reactivity of olfactory neurons was accompanied with an increased activity of receptor-specific glomeruli. In search for mechanisms underlying the ghrelin-mediated sensitization of olfactory neurons, it was shown that Ghsr1a, the ghrelin receptor gene, but not the hormone itself was expressed in the olfactory epithelium. Further analysis of isolated cells revealed that the receptor was in fact expressed in mature olfactory sensory neurons. Treatment with a ghrelin receptor antagonist abolished the ghrelin effect, strengthening the notion that ghrelin and its receptor are responsible for the enhanced neuronal responsiveness. In contrast to the effects of the "hunger" hormone ghrelin, the short-term "satiety" hormone PYY3-36 did not affect olfactory responsiveness. The results demonstrate that ghrelin, which signals acute hunger, renders the olfactory system more responsive to odors.

  15. Tract-tracing study of the extrabulbar olfactory projections in the brain of some teleosts.

    PubMed

    D'aniello, Biagio; Luongo, Luciano; Rastogi, Rakesh K; Di Meglio, Maria; Pinelli, Claudia

    2015-04-01

    The extrabulbar olfactory projections (EBOP) is a collection of nerve fibers that originate from primary olfactory receptor neurons. These fibers penetrate into the brain, bypassing the olfactory bulbs (OBs). While the presence of an EBOP has been well established in teleosts, here we morphologically characterize the EBOP structure in four species each with a different morphological relationship of OB with the ventral telencephalic area. Tract-tracing methods (carbocyanine DiI/DIA and biocytin) were used. FMRFamide immunoreactive nervus terminalis (NT) components were also visualized to define any neuroanatomical relationship between the NT and EBOP. Unilateral DiI/DiA application to the olfactory chamber stained the entire olfactory epithelium, olfactory nerve fibers, and ipsilateral olfactory bulb. Labeled primary olfactory fibers running ventromedially as extrabulbar primary olfactory projections reached various regions of the secondary prosencephalon. Only in Moenkhausia sanctaefilomenae (no olfactory peduncle) did lipophilic tracer-labeled fibers reach the ipsilateral mesencephalon. The combination of tracing techniques and FMRFamide immunohistochemistry revealed a substantial overlap of the label along the olfactory pathways as well as in the anterior secondary prosencephalon. However, FMRFamide immunoreactivity was never colocalized in the same cellular or fiber component as visualized using tracer molecules. Our results showed a certain uniformity in the neuroanatomy and extension of EBOP in all four species, independent of the pedunculate feature of the OBs. The present study also provided additional evidence to support the view that EBOP and FMRFamide immunoreactive components of the NT are separate anatomical entities. PMID:25663434

  16. Transcriptional biomarkers and mechanisms of copper-induced olfactory injury in zebrafish.

    PubMed Central

    Tilton, Fred; Tilton, Susan C.; Bammler, Theo K.; Beyer, Richard; Farin, Frederico; Stapleton, Patricia L.; Gallagher, Evan P.

    2012-01-01

    Metals such as copper disrupt olfactory function in fish. Unfortunately, little is understood of the molecular consequences of copper olfactory impairment, thus hindering the development of relevant diagnostic tools of olfactory injury. To address this critical data gap, we analyzed gene expression within olfactory tissues of adult zebrafish exposed to CuCl2 (6, 16, 40 ppb) for 24 hrs. Transcriptional markers of copper impairment within the entire olfactory system were identified and specific genes of interest (e.g. S100a, parvalbumin 8, olfactory marker protein, and calbindin 2-like protein) were confirmed with quantitative real-time PCR. In addition, we performed gene set analysis (GSA) using both a-priori and custom pathways of gene sets specifically targeting the olfactory signal transduction (OST) pathway. These analyses revealed down-regulated gene sets related to calcium channels and ion transport, g-proteins, and olfactory receptors. Collectively, these data demonstrate that copper causes a depression of transcription of key genes within the OST pathway and elsewhere within olfactory tissues, likely resulting in an olfactory system less responsive to odorants. Further, these data provide a mechanistic explanation in support of earlier studies of functional olfactory impairment in fish following copper exposure. PMID:19174923

  17. Oil shale, shale oil, shale gas and non-conventional hydrocarbons

    NASA Astrophysics Data System (ADS)

    Clerici, A.; Alimonti, G.

    2015-08-01

    In recent years there has been a world "revolution" in the field of unconventional hydrocarbon reserves, which goes by the name of "shale gas", gas contained inside clay sediments micropores. Shale gas finds particular development in the United States, which are now independent of imports and see a price reduction to less than one third of that in Europe. With the high oil prices, in addition to the non-conventional gas also "oil shales" (fine-grained sedimentary rocks that contain a large amount of organic material to be used both to be directly burned or to extract liquid fuels which go under the name of shale oil), extra heavy oils and bitumen are becoming an industrial reality. Both unconventional gas and oil reserves far exceed in the world the conventional oil and gas reserves, subverting the theory of fossil fuels scarcity. Values and location of these new fossil reserves in different countries and their production by comparison with conventional resources are presented. In view of the clear advantages of unconventional fossil resources, the potential environmental risks associated with their extraction and processing are also highlighted.

  18. Non-conventional Anderson localization in a matched quarter stack with metamaterials

    NASA Astrophysics Data System (ADS)

    Torres-Herrera, E. J.; Izrailev, F. M.; Makarov, N. M.

    2013-05-01

    We study the problem of non-conventional Anderson localization emerging in bilayer periodic-on-average structures with alternating layers of materials, with positive and negative refraction indices na and nb. Attention is paid to the model of the so-called quarter stack with perfectly matched layers (the same unperturbed by disorder impedances, Za = Zb, and optical path lengths, nada = |nb|db, with da and db being the thicknesses of basic layers). As was recently numerically discovered, in such structures with weak fluctuations of refractive indices (compositional disorder), the localization length Lloc is enormously large in comparison to the conventional localization occurring in the structures with positive refraction indices only. In this paper we develop a new approach, which allows us to derive the expression for Lloc for weak disorder and any wave frequency ω. In the limit ω → 0 one gets a quite specific dependence, L-1loc∝σ4ω8, which is obtained within the fourth order of perturbation theory. We also analyze the interplay between two types of disorder, when in addition to the fluctuations of na and nb, the thicknesses da and db slightly fluctuate as well (positional disorder). We show how conventional localization recovers with the addition of positional disorder.

  19. Application of anhydrobiosis and dehydration of yeasts for non-conventional biotechnological goals.

    PubMed

    Rapoport, Alexander; Turchetti, Benedetta; Buzzini, Pietro

    2016-06-01

    Dehydration of yeast cells causes them to enter a state of anhydrobiosis in which their metabolism is temporarily and reversibly suspended. This unique state among organisms is currently used in the production of active dry yeasts, mainly used in baking and winemaking. In recent decades non-conventional applications of yeast dehydration have been proposed for various modern biotechnologies. This mini-review briefly summarises current information on the application of dry yeasts in traditional and innovative fields. It has been shown that dry yeast preparations can be used for the efficient protection, purification and bioremediation of the environment from heavy metals. The high sorption activity of dehydrated yeasts can be used as an interesting tool in winemaking due to their effects on quality and taste. Dry yeasts are also used in agricultural animal feed. Another interesting application of yeast dehydration is as an additional stage in new methods for the stable immobilisation of microorganisms, especially in cases when biotechnologically important strains have no affinity with the carrier. Such immobilisation methods also provide a new approach for the successful conservation of yeast strains that are very sensitive to dehydration. In addition, the application of dehydration procedures opens up new possibilities for the use of yeast as a model system. Separate sections of this review also discuss possible uses of dry yeasts in biocontrol, bioprotection and biotransformations, in analytical methods as well as in some other areas. PMID:27116970

  20. Chemical composition and starch digestibility of tortillas prepared with non-conventional commercial nixtamalized maize flours.

    PubMed

    Hernández-Salazar, M; Agama-Acevedo, E; Sáyago-Ayerdi, S G; Tovar, J; Bello-Pérez, L A

    2006-01-01

    Non-conventional nixtamalized maize flours elaborated by a factory in Mexico were used for tortilla preparation. Tortillas were stored at 4 degrees C for up to 72 h and the total starch, available starch, resistant starch and retrograded resistant starch were assessed. The traditional white tortilla, used as a control, showed higher protein and fat contents than blue maize tortilla, whereas a maize-bean mixed tortilla had the highest protein, ash and fat contents. Lower total starch was obtained in the maize-bean tortilla than in white and blue maize tortillas. The available starch content in all tortillas decreased with the cold-storage, although the change was more marked for blue-maize tortillas. The maize-bean mixed tortillas exhibited the lowest in vitro digestibility, which is consistent with the relatively high resistant starch levels in the bean. Differences in resistant starch content were found between the two maize tortillas, which might be related to the softer texture of blue-maize tortilla. The starch digestibility features of these new types of nixtamalized maize flours open up the possibility of producing tortillas with variable nutritional properties.

  1. Effects of Yttrium-90 selective internal radiation therapy on non-conventional liver tumors.

    PubMed

    Kuei, Andrew; Saab, Sammy; Cho, Sung-Ki; Kee, Stephen T; Lee, Edward Wolfgang

    2015-07-21

    The liver is a common site of metastasis, with essentially all metastatic malignancies having been known to spread to the liver. Nearly half of all patients with extrahepatic primary cancer have hepatic metastases. The severe prognostic implications of hepatic metastases have made surgical resection an important first line treatment in management. However, limitations such as the presence of extrahepatic spread or poor functional hepatic reserve exclude the majority of patients as surgical candidates, leaving chemotherapy and locoregional therapies as next best options. Selective internal radiation therapy (SIRT) is a form of catheter-based locoregional cancer treatment modality for unresectable tumors, involving trans-arterial injection of microspheres embedded with a radio-isotope Yttrium-90. The therapeutic radiation dose is selectively delivered as the microspheres permanently embed themselves within the tumor vascular bed. Use of SIRT has been conventionally aimed at treating primary hepatic tumors (hepatocellular carcinoma) or colorectal and neuroendocrine metastases. Numerous reviews are available for these tumor types. However, little is known or reviewed on non-colorectal or non-neuroendocrine primaries. Therefore, the aim of this paper is to systematically review the current literature to evaluate the effects of Yttrium-90 radioembolization on non-conventional liver tumors including those secondary to breast cancer, cholangiocarcinoma, ocular and percutaneous melanoma, pancreatic cancer, renal cell carcinoma, and lung cancer.

  2. An endocannabinoid system is present in the mouse olfactory epithelium but does not modulate olfaction.

    PubMed

    Hutch, C R; Hillard, C J; Jia, C; Hegg, C C

    2015-08-01

    Endocannabinoids modulate a diverse array of functions including progenitor cell proliferation in the central nervous system, and odorant detection and food intake in the mammalian central olfactory system and larval Xenopus laevis peripheral olfactory system. However, the presence and role of endocannabinoids in the peripheral olfactory epithelium have not been examined in mammals. We found the presence of cannabinoid type 1 (CB1) and cannabinoid type 2 (CB2) receptor protein and mRNA in the olfactory epithelium. Using either immunohistochemistry or calcium imaging we localized CB1 receptors on neurons, glia-like sustentacular cells, microvillous cells and progenitor-like basal cells. To examine the role of endocannabinoids, CB1- and CB2- receptor-deficient (CB1(-/-)/CB2(-/-)) mice were used. The endocannabinoid 2-arachidonylglycerol (2-AG) was present at high levels in both C57BL/6 wildtype and CB1(-/-)/CB2(-/-) mice. 2-AG synthetic and degradative enzymes are expressed in wildtype mice. A small but significant decrease in basal cell and olfactory sensory neuron numbers was observed in CB1(-/-)/CB2(-/-) mice compared to wildtype mice. The decrease in olfactory sensory neurons did not translate to impairment in olfactory-mediated behaviors assessed by the buried food test and habituation/dishabituation test. Collectively, these data indicate the presence of an endocannabinoid system in the mouse olfactory epithelium. However, unlike in tadpoles, endocannabinoids do not modulate olfaction. Further investigation on the role of endocannabinoids in progenitor cell function in the olfactory epithelium is warranted. PMID:26037800

  3. An endocannabinoid system is present in the mouse olfactory epithelium but does not modulate olfaction.

    PubMed

    Hutch, C R; Hillard, C J; Jia, C; Hegg, C C

    2015-08-01

    Endocannabinoids modulate a diverse array of functions including progenitor cell proliferation in the central nervous system, and odorant detection and food intake in the mammalian central olfactory system and larval Xenopus laevis peripheral olfactory system. However, the presence and role of endocannabinoids in the peripheral olfactory epithelium have not been examined in mammals. We found the presence of cannabinoid type 1 (CB1) and cannabinoid type 2 (CB2) receptor protein and mRNA in the olfactory epithelium. Using either immunohistochemistry or calcium imaging we localized CB1 receptors on neurons, glia-like sustentacular cells, microvillous cells and progenitor-like basal cells. To examine the role of endocannabinoids, CB1- and CB2- receptor-deficient (CB1(-/-)/CB2(-/-)) mice were used. The endocannabinoid 2-arachidonylglycerol (2-AG) was present at high levels in both C57BL/6 wildtype and CB1(-/-)/CB2(-/-) mice. 2-AG synthetic and degradative enzymes are expressed in wildtype mice. A small but significant decrease in basal cell and olfactory sensory neuron numbers was observed in CB1(-/-)/CB2(-/-) mice compared to wildtype mice. The decrease in olfactory sensory neurons did not translate to impairment in olfactory-mediated behaviors assessed by the buried food test and habituation/dishabituation test. Collectively, these data indicate the presence of an endocannabinoid system in the mouse olfactory epithelium. However, unlike in tadpoles, endocannabinoids do not modulate olfaction. Further investigation on the role of endocannabinoids in progenitor cell function in the olfactory epithelium is warranted.

  4. Expression of corticosteroid binding globulin in the rat olfactory system.

    PubMed

    Dölz, Wilfried; Eitner, Annett; Caldwell, Jack D; Jirikowski, Gustav F

    2013-05-01

    Glucocorticoids are known to act on the olfactory system although their mode of action is still unclear since nuclear glucocorticoid receptors are mostly absent in the olfactory mucosa. In this study we used immunocytochemistry, in situ hybridization, and RT-PCR to study the expression and distribution of corticosteroid binding globulin (CBG) in the rat olfactory system. Mucosal goblet cells could be immunostained for CBG. Nasal secretion contained measurable amounts of CBG suggesting that CBG is liberated. CBG immunoreactivity was localized in many of the basal cells of the olfactory mucosa, while mature sensory cells contained CBG only in processes as determined by double immunostaining with the olfactory marker protein OMP. This staining was most pronounced in the vomeronasal organ (VNO). The appearance of CBG in the non-sensory and sensory parts of the VNO and in nerve terminals in the accessory bulb indicated axonal transport. Portions of the periglomerular cells, the mitral cells and the tufted cells were also CBG positive. CBG encoding transcripts were confirmed by RT-PCR in homogenates of the olfactory mucosa and VNO. Olfactory CBG may be significant for uptake, accumulation and transport of glucocorticoids, including aerosolic cortisol.

  5. Nitric oxide synthesis in locust olfactory interneurones

    PubMed

    Elphick; Rayne; Riveros-Moreno; Moncada; Shea

    1995-01-01

    The brain of the locust Schistocerca gregaria contains a nitric oxide synthase (NOS) that has similar properties to mammalian neuronal NOS. It catalyses the production of equimolar quantities of nitric oxide (NO) and citrulline from l-arginine in a Ca2+/calmodulin- and NADPH-dependent manner and is inhibited by the Nomega-nitro and Nomega-monomethyl analogues of l-arginine. In Western blots, an antiserum to the 160 kDa rat cerebellar NOS subunit recognises a locust brain protein with a molecular mass of approximately 135 kDa. NOS is located in several parts of the locust brain, including the mushroom bodies, but it is particularly abundant in the olfactory processing centres, the antennal lobes. Here it is present in two groups of local interneurones (a pair and a cluster of about 50) that project into the neuropile of the antennal lobes. The processes of these neurones terminate in numerous glomerulus-like structures where the synapses between primary olfactory receptor neurones and central interneurones are formed. NOS-containing local interneurones have also been identified in the mammalian olfactory bulb, suggesting that NO performs analogous functions in locust and mammalian olfactory systems. As yet, nothing is known about the role of NO in olfaction, but it seems likely that it is involved in the processing of chemosensory input to the brain. The locust antennal lobe may be an ideal 'simple' system in which this aspect of NO function can be examined.

  6. Olfactory Learning in Drosophila

    PubMed Central

    Busto, Germain U.; Cervantes-Sandoval, Isaac; Davis, Ronald L.

    2012-01-01

    Studies of olfactory learning in Drosophila have provided key insights into the brain mechanisms underlying learning and memory. One type of olfactory learning, olfactory classical conditioning, consists of learning the contingency between an odor with an aversive or appetitive stimulus. This conditioning requires the activity of molecules that can integrate the two types of sensory information, the odorant as the conditioned stimulus and the aversive or appetitive stimulus as the unconditioned stimulus, in brain regions where the neural pathways for the two stimuli intersect. Compelling data indicate that a particular form of adenylyl cyclase functions as a molecular integrator of the sensory information in the mushroom body neurons. The neuronal pathway carrying the olfactory information from the antennal lobes to the mushroom body is well described. Accumulating data now show that some dopaminergic neurons provide information about aversive stimuli and octopaminergic neurons about appetitive stimuli to the mushroom body neurons. Inhibitory inputs from the GABAergic system appear to gate olfactory information to the mushroom bodies and thus control the ability to learn about odors. Emerging data obtained by functional imaging procedures indicate that distinct memory traces form in different brain regions and correlate with different phases of memory. The results from these and other experiments also indicate that cross talk between mushroom bodies and several other brain regions is critical for memory formation. PMID:21186278

  7. Improving ITC studies of cyclodextrin inclusion compounds by global analysis of conventional and non-conventional experiments

    PubMed Central

    Bertaut, Eléonore

    2014-01-01

    Summary The study of 1:1 cyclodextrin inclusion compounds by isothermal titration calorimetry was explored in a theoretical and experimental point of view to compare the efficiency of conventional and non-conventional experiments. All direct and competitive protocols were described and evaluated in terms of accuracy on both binding constant and inclusion enthalpy. Significant improvement in the calorimetric characterization may be obtained by means of the global analysis of non-conventional experiments coupled to the standard titration protocol. While the titration-release approach proved to be the most accurate strategy for classical complexations, the valuable contribution of other non-conventional experiments was demonstrated for issues concerning weak stability, enthalpy, or solubility. PMID:25550724

  8. Genetic control of wiring specificity in the fly olfactory system.

    PubMed

    Hong, Weizhe; Luo, Liqun

    2014-01-01

    Precise connections established between pre- and postsynaptic partners during development are essential for the proper function of the nervous system. The olfactory system detects a wide variety of odorants and processes the information in a precisely connected neural circuit. A common feature of the olfactory systems from insects to mammals is that the olfactory receptor neurons (ORNs) expressing the same odorant receptor make one-to-one connections with a single class of second-order olfactory projection neurons (PNs). This represents one of the most striking examples of targeting specificity in developmental neurobiology. Recent studies have uncovered central roles of transmembrane and secreted proteins in organizing this one-to-one connection specificity in the olfactory system. Here, we review recent advances in the understanding of how this wiring specificity is genetically controlled and focus on the mechanisms by which transmembrane and secreted proteins regulate different stages of the Drosophila olfactory circuit assembly in a coordinated manner. We also discuss how combinatorial coding, redundancy, and error-correcting ability could contribute to constructing a complex neural circuit in general.

  9. Acetylcholine and Olfactory Perceptual Learning

    ERIC Educational Resources Information Center

    Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

    2004-01-01

    Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform…

  10. Effects of urea on the molecules involved in the olfactory signal transduction: a preliminary study on Danio rerio.

    PubMed

    Ferrando, Sara; Gallus, Lorenzo; Gambardella, Chiara; Marchesotti, Emiliano; Ravera, Silvia; Franceschini, Valeria; Masini, Maria Angela

    2014-12-01

    Among vertebrates, the physiologically uremic Chondrichthyes are the only class which are not presenting the ciliated olfactory receptor neurons in the olfactory neuroepithelium. The only sequenced genome for this class revealed only three olfactory receptor genes and the immunohistochemical detection of G protein alpha subunit typically coupled to the olfactory receptors (Gα(olf)) failed in different species. Chronic renal disease can represent a cause of olfactory impairment in human. In this context, our present study focused on investigating potential effects of high urea concentration on the olfactory epithelium of vertebrates. Larvae of the teleost fish Danio rerio were exposed to urea in order to assess the effects on the olfactory signal transduction; in particular on both the olfactory receptors and the Gα(olf). The endocytosis of neutral red dye in the olfactory mucosa was detected in control and urea-exposed larvae. The amount of neutral red dye uptake was used as a marker of binding and internalization of the Gα(olf). The neutral red dye endocytosis was not affected by urea exposure, hence suggesting that the presence of the Gα(olf) and their binding to the odorants are not affected by urea treatment, either. The presence and distribution of Gα(olf) were investigated in the olfactory epithelium of control and urea-exposed larvae, using a commercial antibody. The immunoreactivity was increased after urea treatment, suggesting an effect of urea on the expression or degradation of this G protein alpha subunit.

  11. Functional Evidence of Multidrug Resistance Transporters (MDR) in Rodent Olfactory Epithelium

    PubMed Central

    Molinas, Adrien; Sicard, Gilles; Jakob, Ingrid

    2012-01-01

    Background P-glycoprotein (Pgp) and multidrug resistance-associated protein (MRP1) are membrane transporter proteins which function as efflux pumps at cell membranes and are considered to exert a protective function against the entry of xenobiotics. While evidence for Pgp and MRP transporter activity is reported for olfactory tissue, their possible interaction and participation in the olfactory response has not been investigated. Principal Findings Functional activity of putative MDR transporters was assessed by means of the fluorometric calcein acetoxymethyl ester (calcein-AM) accumulation assay on acute rat and mouse olfactory tissue slices. Calcein-AM uptake was measured as fluorescence intensity changes in the presence of Pgp or MRP specific inhibitors. Epifluorescence microscopy measured time course analysis in the olfactory epithelium revealed significant inhibitor-dependent calcein uptake in the presence of each of the selected inhibitors. Furthermore, intracellular calcein accumulation in olfactory receptor neurons was also significantly increased in the presence of either one of the Pgp or MRP inhibitors. The presence of Pgp or MRP1 encoding genes in the olfactory mucosa of rat and mouse was confirmed by RT-PCR with appropriate pairs of species-specific primers. Both transporters were expressed in both newborn and adult olfactory mucosa of both species. To assess a possible involvement of MDR transporters in the olfactory response, we examined the electrophysiological response to odorants in the presence of the selected MDR inhibitors by recording electroolfactograms (EOG). In both animal species, MRPs inhibitors induced a marked reduction of the EOG magnitude, while Pgp inhibitors had only a minor or no measurable effect. Conclusions The findings suggest that both Pgp and MRP transporters are functional in the olfactory mucosa and in olfactory receptor neurons. Pgp and MRPs may be cellular constituents of olfactory receptor neurons and represent potential

  12. Unravelling the Olfactory Sense: From the Gene to Odor Perception.

    PubMed

    Silva Teixeira, Carla S; Cerqueira, Nuno M F S A; Silva Ferreira, António C

    2016-02-01

    Although neglected by science for a long time, the olfactory sense is now the focus of a panoply of studies that bring new insights and raises interesting questions regarding its functioning. The importance in the clarification of this process is of interest for science, but also motivated by the food and perfume industries boosted by a consumer society with increasingly demands for higher quality standards. In this review, a general overview of the state of art of science regarding the olfactory sense is presented with the main focus on the peripheral olfactory system. Special emphasis will be given to the deorphanization of the olfactory receptors (ORs), a critical issue because the specificity and functional properties of about 90% of human ORs remain unknown mainly due to the difficulties associated with the functional expression of ORs in high yields.

  13. Unravelling the Olfactory Sense: From the Gene to Odor Perception.

    PubMed

    Silva Teixeira, Carla S; Cerqueira, Nuno M F S A; Silva Ferreira, António C

    2016-02-01

    Although neglected by science for a long time, the olfactory sense is now the focus of a panoply of studies that bring new insights and raises interesting questions regarding its functioning. The importance in the clarification of this process is of interest for science, but also motivated by the food and perfume industries boosted by a consumer society with increasingly demands for higher quality standards. In this review, a general overview of the state of art of science regarding the olfactory sense is presented with the main focus on the peripheral olfactory system. Special emphasis will be given to the deorphanization of the olfactory receptors (ORs), a critical issue because the specificity and functional properties of about 90% of human ORs remain unknown mainly due to the difficulties associated with the functional expression of ORs in high yields. PMID:26688501

  14. Misexpression screen for genes altering the olfactory map in Drosophila.

    PubMed

    Zhang, Dongsheng; Zhou, Weiguang; Yin, Chong; Chen, Weitao; Ozawa, Rie; Ang, Lay-Hong; Anandan, Lavanya; Aigaki, Toshiro; Hing, Huey

    2006-04-01

    Despite the identification of a number of guidance molecules, a comprehensive picture has yet to emerge to explain the precise anatomy of the olfactory map. From a misexpression screen of 1,515 P{GS} lines, we identified 23 genes that, when forcibly expressed in the olfactory receptor neurons, disrupted the stereotyped anatomy of the Drosophila antennal lobes. These genes, which have not been shown previously to control olfactory map development, encode novel proteins as well as proteins with known roles in axonal outgrowth and cytoskeletal remodeling. We analyzed Akap200, which encodes a Protein Kinase A-binding protein. Overexpression of Akap200 resulted in fusion of the glomeruli, while its loss resulted in misshapen and ectopic glomeruli. The requirement of Akap200 validates our screen as an effective approach for recovering genes controlling glomerular map patterning. Our finding of diverse classes of genes reveals the complexity of the mechanisms that underlie olfactory map development.

  15. Increasing olfactory bulb volume due to treatment of chronic rhinosinusitis--a longitudinal study.

    PubMed

    Gudziol, V; Buschhüter, D; Abolmaali, N; Gerber, J; Rombaux, P; Hummel, T

    2009-11-01

    Differentiation of progenitor cells into neurons in the olfactory bulb depends on olfactory stimulation that can lead to an increase in olfactory bulb volume. In this study, we investigated whether the human olfactory bulb volume increases with increasing olfactory function due to treatment of chronic rhinosinusitis. Nineteen patients with chronic rhinosinusitis were investigated before and after treatment. For comparison, additional measurements were performed in 18 healthy volunteers. Volumetric measurements of the olfactory bulb were based on planimetric manual contouring of magnetic resonance scans. Olfactory function was evaluated separately for each nostril using tests for odour threshold, odour discrimination and odour identification. Measurements were performed on two occasions, 3 months apart. In healthy controls, the olfactory bulb volume did not change significantly between the two measurements. In contrast, the olfactory bulb volume in patients increased significantly from the initial 64.5 +/- 3.2 to 70.0 +/- 3.5 mm(3) on the left side (P = 0.02) and from 60.9 +/- 3.5 to 72.4 +/- 2.8 mm(3) on the right side (P < 0.001). The increase in olfactory bulb volume correlated significantly with an increase in odour thresholds (r = 0.60, P = 0.006, left side; r = 0.49, P = 0.03, right side), but not with changes in odour discrimination or odour identification. Results of this study support the idea that stimulation of olfactory receptor neurons impacts on the cell death in the olfactory bulb, not only in rodents but also in humans. To our knowledge, this is the first longitudinal study that describes an enlargement of the human olfactory bulb due to improvement of peripheral olfactory function. PMID:19773353

  16. Non-conventional Yeast Species for Lowering Ethanol Content of Wines

    PubMed Central

    Ciani, Maurizio; Morales, Pilar; Comitini, Francesca; Tronchoni, Jordi; Canonico, Laura; Curiel, José A.; Oro, Lucia; Rodrigues, Alda J.; Gonzalez, Ramon

    2016-01-01

    Rising sugar content in grape must, and the concomitant increase in alcohol levels in wine, are some of the main challenges affecting the winemaking industry nowadays. Among the several alternative solutions currently under study, the use of non-conventional yeasts during fermentation holds good promise for contributing to relieve this problem. Non-Saccharomyces wine yeast species comprise a high number or species, so encompassing a wider physiological diversity than Saccharomyces cerevisiae. Indeed, the current oenological interest of these microorganisms was initially triggered by their potential positive contribution to the sensorial complexity of quality wines, through the production of aroma and other sensory-active compounds. This diversity also involves ethanol yield on sugar, one of the most invariant metabolic traits of S. cerevisiae. This review gathers recent research on non-Saccharomyces yeasts, aiming to produce wines with lower alcohol content than those from pure Saccharomyces starters. Critical aspects discussed include the selection of suitable yeast strains (considering there is a noticeable intra-species diversity for ethanol yield, as shown for other fermentation traits), identification of key environmental parameters influencing ethanol yields (including the use of controlled oxygenation conditions), and managing mixed fermentations, by either the sequential or simultaneous inoculation of S. cerevisiae and non-Saccharomyces starter cultures. The feasibility, at the industrial level, of using non-Saccharomyces yeasts for reducing alcohol levels in wine will require an improved understanding of the metabolism of these alternative yeast species, as well as of the interactions between different yeast starters during the fermentation of grape must. PMID:27199967

  17. Metabolic engineering of the non-conventional yeast Pichia ciferrii for production of rare sphingoid bases.

    PubMed

    Börgel, Daniel; van den Berg, Marco; Hüller, Thomas; Andrea, Heiko; Liebisch, Gerhard; Boles, Eckhard; Schorsch, Christoph; van der Pol, Ruud; Arink, Anne; Boogers, Ilco; van der Hoeven, Rob; Korevaar, Kees; Farwick, Mike; Köhler, Tim; Schaffer, Steffen

    2012-07-01

    The study describes the identification of sphingolipid biosynthesis genes in the non-conventional yeast Pichia ciferrii, the development of tools for its genetic modification as well as their application for metabolic engineering of P. ciferrii with the goal to generate strains capable of producing the rare sphingoid bases sphinganine and sphingosine. Several canonical genes encoding ceramide synthase (encoded by PcLAG1 and PcLAF1), alkaline ceramidase (PcYXC1) and sphingolipid C-4-hydroxylase(PcSYR2), as well as structural genes for dihydroceramide Δ(4)-desaturase (PcDES1) and sphingolipid Δ(8)-desaturase (PcSLD1) were identified, indicating that P. ciferrii would be capable of synthesizing desaturated sphingoid bases, a property not ubiquitously found in yeasts. In order to convert the phytosphingosine-producing P. ciferrii wildtype into a strain capable of producing predominantly sphinganine, Syringomycin E-resistant mutants were isolated. A stable mutant almost exclusively producing high levels of acetylated sphinganine was obtained and used as the base strain for further metabolic engineering. A metabolic pathway required for the three-step conversion of sphinganine to sphingosine was implemented in the sphinganine producing P. ciferrii strain and subsequently enhanced by screening for the appropriate heterologous enzymes, improvement of gene expression and codon optimization. These combined efforts led to a strain capable of producing 240mgL(-1) triacetyl sphingosine in shake flask, with tri- and diacetyl sphinganine being the main by-products. Lab-scale fermentation of this strain resulted in production of up to 890mgkg(-1) triacetyl sphingosine. A third by-product was unequivocally identified as triacetyl sphingadienine. It could be shown that inactivation of the SLD1 gene in P. ciferrii efficiently suppresses triacetyl sphingadienine formation. Further improvement of the described P. ciferrii strains will enable a biotechnological route to produce

  18. Non-conventional Yeast Species for Lowering Ethanol Content of Wines.

    PubMed

    Ciani, Maurizio; Morales, Pilar; Comitini, Francesca; Tronchoni, Jordi; Canonico, Laura; Curiel, José A; Oro, Lucia; Rodrigues, Alda J; Gonzalez, Ramon

    2016-01-01

    Rising sugar content in grape must, and the concomitant increase in alcohol levels in wine, are some of the main challenges affecting the winemaking industry nowadays. Among the several alternative solutions currently under study, the use of non-conventional yeasts during fermentation holds good promise for contributing to relieve this problem. Non-Saccharomyces wine yeast species comprise a high number or species, so encompassing a wider physiological diversity than Saccharomyces cerevisiae. Indeed, the current oenological interest of these microorganisms was initially triggered by their potential positive contribution to the sensorial complexity of quality wines, through the production of aroma and other sensory-active compounds. This diversity also involves ethanol yield on sugar, one of the most invariant metabolic traits of S. cerevisiae. This review gathers recent research on non-Saccharomyces yeasts, aiming to produce wines with lower alcohol content than those from pure Saccharomyces starters. Critical aspects discussed include the selection of suitable yeast strains (considering there is a noticeable intra-species diversity for ethanol yield, as shown for other fermentation traits), identification of key environmental parameters influencing ethanol yields (including the use of controlled oxygenation conditions), and managing mixed fermentations, by either the sequential or simultaneous inoculation of S. cerevisiae and non-Saccharomyces starter cultures. The feasibility, at the industrial level, of using non-Saccharomyces yeasts for reducing alcohol levels in wine will require an improved understanding of the metabolism of these alternative yeast species, as well as of the interactions between different yeast starters during the fermentation of grape must. PMID:27199967

  19. Neuropeptide complexity in the crustacean central olfactory pathway: immunolocalization of A-type allatostatins and RFamide-like peptides in the brain of a terrestrial hermit crab

    PubMed Central

    2012-01-01

    Background In the olfactory system of malacostracan crustaceans, axonal input from olfactory receptor neurons associated with aesthetascs on the animal’s first pair of antennae target primary processing centers in the median brain, the olfactory lobes. The olfactory lobes are divided into cone-shaped synaptic areas, the olfactory glomeruli where afferents interact with local olfactory interneurons and olfactory projection neurons. The local olfactory interneurons display a large diversity of neurotransmitter phenotypes including biogenic amines and neuropeptides. Furthermore, the malacostracan olfactory glomeruli are regionalized into cap, subcap, and base regions and these compartments are defined by the projection patterns of the afferent olfactory receptor neurons, the local olfactory interneurons, and the olfactory projection neurons. We wanted to know how neurons expressing A-type allatostatins (A-ASTs; synonym dip-allatostatins) integrate into this system, a large family of neuropeptides that share the C-terminal motif –YXFGLamide. Results We used an antiserum that was raised against the A-type Diploptera punctata (Dip)-allatostatin I to analyse the distribution of this peptide in the brain of a terrestrial hermit crab, Coenobita clypeatus (Anomura, Coenobitidae). Allatostatin A-like immunoreactivity (ASTir) was widely distributed in the animal’s brain, including the visual system, central complex and olfactory system. We focussed our analysis on the central olfactory pathway in which ASTir was abundant in the primary processing centers, the olfactory lobes, and also in the secondary centers, the hemiellipsoid bodies. In the olfactory lobes, we further explored the spatial relationship of olfactory interneurons with ASTir to interneurons that synthesize RFamide-like peptides. We found that these two peptides are present in distinct populations of local olfactory interneurons and that their synaptic fields within the olfactory glomeruli are also mostly

  20. Dendritic Organization of Olfactory Inputs to Medial Amygdala Neurons.

    PubMed

    Keshavarzi, Sepideh; Power, John M; Albers, Eva H H; Sullivan, Robert K S; Sah, Pankaj

    2015-09-23

    The medial amygdala (MeA) is a central hub in the olfactory neural network. It receives vomeronasal information directly from the accessory olfactory bulb (AOB) and main olfactory information largely via odor-processing regions such as the olfactory cortical amygdala (CoA). How these inputs are processed by MeA neurons is poorly understood. Using the GAD67-GFP mouse, we show that MeA principal neurons receive convergent AOB and CoA inputs. Somatically recorded AOB synaptic inputs had slower kinetics than CoA inputs, suggesting that they are electrotonically more distant. Field potential recording, pharmacological manipulation, and Ca(2+) imaging revealed that AOB synapses are confined to distal dendrites and segregated from the proximally located CoA synapses. Moreover, unsynchronized AOB inputs had significantly broader temporal summation that was dependent on the activation of NMDA receptors. These findings show that MeA principal neurons process main and accessory olfactory inputs differentially in distinct dendritic compartments. Significance statement: In most vertebrates, olfactory cues are processed by two largely segregated neural pathways, the main and accessory olfactory systems, which are specialized to detect odors and nonvolatile chemosignals, respectively. Information from these two pathways ultimately converges at higher brain regions, one of the major hubs being the medial amygdala. Little is known about how olfactory inputs are processed by medial amygdala neurons. This study shows that individual principal neurons in this region receive input from both pathways and that these synapses are spatially segregated on their dendritic tree. We provide evidence suggesting that this dendritic segregation leads to distinct input integration and impact on neuronal output; hence, dendritic mechanisms control olfactory processing in the amygdala. PMID:26400933

  1. Direct transport of inhaled xylene and its metabolites from the olfactory mucosa to the glomeruli of the olfactory bulbs

    SciTech Connect

    Lewis, J.L.; Dahl, A.R.; Kracko, D.A.

    1994-11-01

    The olfactory epithelium is a unique tissue in that single receptor neurons have dendrites in contact with the external environment at the nasal airway, and axon terminals that penetrate the cribriform plate and synapse in the olfactory bulb. The Central Nervous System (CNS) is protected from systematically circulating toxicants by a blood-brain barrier primarily composed of tight junctions between endothelial cells in cerebral vessels and a high metabolic capacity within these cells. No such barrier has yet been defined to protect the CNS from inhaled toxicants. Because all inhalants do not seem to access the CNS directly, a nose-brain barrier seems plausible. The purpose of the work described here is to determine whether or not a nose-brain barrier exists and to define its components. Although such a barrier is likely to be multi-faceted, the present work focuses only on the importance of gross histologic and metabolic characteristics of the olfactory epithelium in olfactory transport.

  2. Peripheral olfactory signaling in insects

    PubMed Central

    Suh, Eunho; Bohbot, Jonathan; Zwiebel, Laurence J.

    2014-01-01

    Olfactory signaling is a crucial component in the life history of insects. The development of precise and parallel mechanisms to analyze the tremendous amount of chemical information from the environment and other sources has been essential to their evolutionary success. Considerable progress has been made in the study of insect olfaction fueled by bioinformatics- based utilization of genomics along with rapid advances in functional analyses. Here we review recent progress in our rapidly emerging understanding of insect peripheral sensory reception and signal transduction. These studies reveal that the nearly unlimited chemical space insects encounter is covered by distinct chemosensory receptor repertoires that are generally derived by species-specific, rapid gene gain and loss, reflecting the evolutionary consequences of adaptation to meet their specific biological needs. While diverse molecular mechanisms have been put forth, often in the context of controversial models, the characterization of the ubiquitous, highly conserved and insect-specific Orco odorant receptor co-receptor has opened the door to the design and development of novel insect control methods to target agricultural pests, disease vectors and even nuisance insects. PMID:25584200

  3. Olfactory dysfunction in Alzheimer's disease.

    PubMed

    Zou, Yong-Ming; Lu, Da; Liu, Li-Ping; Zhang, Hui-Hong; Zhou, Yu-Ying

    2016-01-01

    Alzheimer's disease (AD) is a common neurodegenerative disorder with the earliest clinical symptom of olfactory dysfunction, which is a potential clinical marker for AD severity and progression. However, many questions remain unanswered. This article reviews relevant research on olfactory dysfunction in AD and evaluates the predictive value of olfactory dysfunction for the epidemiological, pathophysiological, and clinical features of AD, as well as for the conversion of cognitive impairment to AD. We summarize problems of existing studies and provide a useful reference for further studies in AD olfactory dysfunction and for clinical applications of olfactory testing. PMID:27143888

  4. Olfactory sensitivity in mammalian species.

    PubMed

    Wackermannová, M; Pinc, L; Jebavý, L

    2016-07-18

    Olfaction enables most mammalian species to detect and discriminate vast numbers of chemical structures called odorants and pheromones. The perception of such chemical compounds is mediated via two major olfactory systems, the main olfactory system and the vomeronasal system, as well as minor systems, such as the septal organ and the Grueneberg ganglion. Distinct differences exist not only among species but also among individuals in terms of their olfactory sensitivity; however, little is known about the mechanisms that determine these differences. In research on the olfactory sensitivity of mammals, scientists thus depend in most cases on behavioral testing. In this article, we reviewed scientific studies performed on various mammalian species using different methodologies and target chemical substances. Human and non-human primates as well as rodents and dogs are the most frequently studied species. Olfactory threshold studies on other species do not exist with the exception of domestic pigs. Olfactory testing performed on seals, elephants, and bats focused more on discriminative abilities than on sensitivity. An overview of olfactory sensitivity studies as well as olfactory detection ability in most studied mammalian species is presented here, focusing on comparable olfactory detection thresholds. The basics of olfactory perception and olfactory sensitivity factors are also described. PMID:27070753

  5. The Seductive Power of an Innovation: Enrolling Non-Conventional Actors in a Drip Irrigation Community in Morocco

    ERIC Educational Resources Information Center

    Benouniche, Maya; Errahj, Mostafa; Kuper, Marcel

    2016-01-01

    Purpose: The aim of this study was to analyze the motivations of non-conventional innovation actors to engage in innovation processes, how their involvement changed the technology and their own social-professional status, and to analyze their role in the diffusion of the innovation. Design/methodology/approach: We studied the innovation process of…

  6. Brain-derived neurotrophic factor (BDNF) expression in normal and regenerating olfactory epithelium of Xenopus laevis.

    PubMed

    Frontera, Jimena Laura; Cervino, Ailen Soledad; Jungblut, Lucas David; Paz, Dante Agustín

    2015-03-01

    Olfactory epithelium has the capability to continuously regenerate olfactory receptor neurons throughout life. Adult neurogenesis results from proliferation and differentiation of neural stem cells, and consequently, olfactory neuroepithelium offers an excellent opportunity to study neural regeneration and the factors involved in the maintenance and regeneration of all their cell types. We analyzed the expression of BDNF in the olfactory system under normal physiological conditions as well as during a massive regeneration induced by chemical destruction of the olfactory epithelium in Xenopus laevis larvae. We described the expression and presence of BDNF in the olfactory epithelium and bulb. In normal physiological conditions, sustentacular (glial) cells and a few scattered basal (stem) cells express BDNF in the olfactory epithelium as well as the granular cells in the olfactory bulb. Moreover, during massive regeneration, we demonstrated a drastic increase in basal cells expressing BDNF as well as an increase in BDNF in the olfactory bulb and nerve. Together these results suggest an important role of BDNF in the maintenance and regeneration of the olfactory system.

  7. Olfactory cell-based biosensor: a first step towards a neurochip of bioelectronic nose.

    PubMed

    Liu, Qingjun; Cai, Hua; Xu, Ying; Li, Yan; Li, Rong; Wang, Ping

    2006-08-15

    Human olfactory system can distinguish thousands of odors. In order to realize the biomimetic design of electronic nose on the principle of mammalian olfactory system, this article reports an olfactory cell-based biosensor as a real bionic technique for odorants detection. Effective cultures of olfactory receptor neurons and olfactory bulb cells have been achieved on the semiconductor chip. Using light-addressable potentiometric sensor (LAPS) as sensing chip to monitor extracellular potential of the neurons, the response under stimulations of the odorants or neurotransmitters, such as acetic acid and glutamic acid, was tested. The results demonstrate that this kind of hybrid system of LAPS and olfactory neurons, which is sensitive to odorous changes, has great potential and is promising to be used as a novel neurochip of bioelectronic nose for detecting odors.

  8. OLFACTORY FUNCTIONS AT THE INTERSECTION BETWEEN ENVIRONMENTAL EXPOSURE TO MANGANESE AND PARKINSONISM

    PubMed Central

    Zoni, Silvia; Bonetti, Giulia; Lucchini, Roberto

    2012-01-01

    The olfactory function can be affected by occupational and environmental exposure to various neurotoxicants that can be transported through the olfactory pathway. Olfactory impairment is a highly recurrent non-motor dysfunction in Parkinson’s disease and is considered an early predictive sign of neurodegeneration. Changes in olfactory perception may be caused by a dopaminergic dysregulation, possibly related to changes at the level of dopamine receptors. Manganese is an essential element that can become neurotoxic in various conditions inducing an overload in the organism. Being actively transported through the olfactory tract, manganese can cause impairment of olfactory function and motor coordination in different age groups like children and elderly. Odor and motor changes are interrelated and may be caused by a Mn-induced dopaminergic dysregulation affecting both functions. Given these findings, further research is imperative on the possible role of manganese exposure as a pathogenetic factor for Parkinsonism. PMID:22664337

  9. Mechanisms of Regulation of Olfactory Transduction and Adaptation in the Olfactory Cilium

    PubMed Central

    Antunes, Gabriela; Sebastião, Ana Maria; Simoes de Souza, Fabio Marques

    2014-01-01

    Olfactory adaptation is a fundamental process for the functioning of the olfactory system, but the underlying mechanisms regulating its occurrence in intact olfactory sensory neurons (OSNs) are not fully understood. In this work, we have combined stochastic computational modeling and a systematic pharmacological study of different signaling pathways to investigate their impact during short-term adaptation (STA). We used odorant stimulation and electroolfactogram (EOG) recordings of the olfactory epithelium treated with pharmacological blockers to study the molecular mechanisms regulating the occurrence of adaptation in OSNs. EOG responses to paired-pulses of odorants showed that inhibition of phosphodiesterases (PDEs) and phosphatases enhanced the levels of STA in the olfactory epithelium, and this effect was mimicked by blocking vesicle exocytosis and reduced by blocking cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and vesicle endocytosis. These results suggest that G-coupled receptors (GPCRs) cycling is involved with the occurrence of STA. To gain insights on the dynamical aspects of this process, we developed a stochastic computational model. The model consists of the olfactory transduction currents mediated by the cyclic nucleotide gated (CNG) channels and calcium ion (Ca2+)-activated chloride (CAC) channels, and the dynamics of their respective ligands, cAMP and Ca2+, and it simulates the EOG results obtained under different experimental conditions through changes in the amplitude and duration of cAMP and Ca2+ response, two second messengers implicated with STA occurrence. The model reproduced the experimental data for each pharmacological treatment and provided a mechanistic explanation for the action of GPCR cycling in the levels of second messengers modulating the levels of STA. All together, these experimental and theoretical results indicate the existence of a mechanism of regulation of STA by signaling pathways that control GPCR

  10. Genomic sequence analysis of the 238-kb swine segment with a cluster of TRIM and olfactory receptor genes located, but with no class I genes, at the distal end of the SLA class I region.

    PubMed

    Ando, Asako; Shigenari, Atsuko; Kulski, Jerzy K; Renard, Christine; Chardon, Patrick; Shiina, Takashi; Inoko, Hidetoshi

    2005-12-01

    Continuous genomic sequence has been previously determined for the swine leukocyte antigen (SLA) class I region from the TNF gene cluster at the border between the major histocompatibility complex (MHC) class III and class I regions to the UBD gene at the telomeric end of the classical class I gene cluster (SLA-1 to SLA-5, SLA-9, SLA-11). To complete the genomic sequence of the entire SLA class I genomic region, we have analyzed the genomic sequences of two BAC clones carrying a continuous 237,633-bp-long segment spanning from the TRIM15 gene to the UBD gene located on the telomeric side of the classical SLA class I gene cluster. Fifteen non-class I genes, including the zinc finger and the tripartite motif (TRIM) ring-finger-related family genes and olfactory receptor genes, were identified in the 238-kilobase (kb) segment, and their location in the segment was similar to their apparent human homologs. In contrast, a human segment (alpha block) spanning about 375 kb from the gene ETF1P1 and from the HLA-J to HLA-F genes was absent from the 238-kb swine segment. We conclude that the gene organization of the MHC non-class I genes located in the telomeric side of the classical SLA class I gene cluster is remarkably similar between the swine and the human segments, although the swine lacks a 375-kb segment corresponding to the human alpha block.

  11. The olfactory nerve: a shortcut for influenza and other viral diseases into the central nervous system.

    PubMed

    van Riel, Debby; Verdijk, Rob; Kuiken, Thijs

    2015-01-01

    The olfactory nerve consists mainly of olfactory receptor neurons and directly connects the nasal cavity with the central nervous system (CNS). Each olfactory receptor neuron projects a dendrite into the nasal cavity on the apical side, and on the basal side extends its axon through the cribriform plate into the olfactory bulb of the brain. Viruses that can use the olfactory nerve as a shortcut into the CNS include influenza A virus, herpesviruses, poliovirus, paramyxoviruses, vesicular stomatitis virus, rabies virus, parainfluenza virus, adenoviruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, La Crosse virus, mouse hepatitis virus, and bunyaviruses. However, mechanisms of transport via the olfactory nerve and subsequent spread through the CNS are poorly understood. Proposed mechanisms are either infection of olfactory receptor neurons themselves or diffusion through channels formed by olfactory ensheathing cells. Subsequent virus spread through the CNS could occur by multiple mechanisms, including trans-synaptic transport and microfusion. Viral infection of the CNS can lead to damage from infection of nerve cells per se, from the immune response, or from a combination of both. Clinical consequences range from nervous dysfunction in the absence of histopathological changes to severe meningoencephalitis and neurodegenerative disease.

  12. Bimodal processing of olfactory information in an amphibian nose: odor responses segregate into a medial and a lateral stream.

    PubMed

    Gliem, Sebastian; Syed, Adnan S; Sansone, Alfredo; Kludt, Eugen; Tantalaki, Evangelia; Hassenklöver, Thomas; Korsching, Sigrun I; Manzini, Ivan

    2013-06-01

    In contrast to the single sensory surface present in teleost fishes, several spatially segregated subsystems with distinct molecular and functional characteristics define the mammalian olfactory system. However, the evolutionary steps of that transition remain unknown. Here we analyzed the olfactory system of an early diverging tetrapod, the amphibian Xenopus laevis, and report for the first time the existence of two odor-processing streams, sharply segregated in the main olfactory bulb and partially segregated in the olfactory epithelium of pre-metamorphic larvae. A lateral odor-processing stream is formed by microvillous receptor neurons and is characterized by amino acid responses and Gαo/Gαi as probable signal transducers, whereas a medial stream formed by ciliated receptor neurons is characterized by responses to alcohols, aldehydes, and ketones, and Gαolf/cAMP as probable signal transducers. To reveal candidates for the olfactory receptors underlying these two streams, the spatial distribution of 12 genes from four olfactory receptor gene families was determined. Several class II and some class I odorant receptors (ORs) mimic the spatial distribution observed for the medial stream, whereas a trace amine-associated receptor closely parallels the spatial pattern of the lateral odor-processing stream. Other olfactory receptors (some class I odorant receptors and vomeronasal type 1 receptors) and odor responses (to bile acids, amines) were not lateralized, the latter not even in the olfactory bulb, suggesting an incomplete segregation. Thus, the olfactory system of X. laevis exhibits an intermediate stage of segregation and as such appears well suited to investigate the molecular driving forces behind olfactory regionalization.

  13. Illuminating odors: when optogenetics brings to light unexpected olfactory abilities.

    PubMed

    Grimaud, Julien; Lledo, Pierre-Marie

    2016-06-01

    For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout.

  14. Illuminating odors: when optogenetics brings to light unexpected olfactory abilities

    PubMed Central

    Grimaud, Julien

    2016-01-01

    For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout. PMID:27194792

  15. Illuminating odors: when optogenetics brings to light unexpected olfactory abilities.

    PubMed

    Grimaud, Julien; Lledo, Pierre-Marie

    2016-06-01

    For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout. PMID:27194792

  16. Lectin histochemical studies on the olfactory epithelium and vomeronasal organ in the Japanese striped snake, Elaphe quadrivirgata.

    PubMed

    Kondoh, Daisuke; Yamamoto, Yoshio; Nakamuta, Nobuaki; Taniguchi, Kazumi; Taniguchi, Kazuyuki

    2010-10-01

    The olfactory epithelium and the vomeronasal organ of the Japanese striped snake were examined by lectin histochemistry. Of the 21 lectins used in the study, all lectins except succinylated-wheat germ agglutinin (s-WGA) showed similar binding patterns in the vomeronasal receptor cells and the olfactory receptor cells with varying intensities. The binding patterns of s-WGA varied among individuals in the vomeronasal and olfactory receptor cells, respectively. Four lectins, Bandeiraea simplicifolia lectin-II (BSL-II), Dolichos biflorus agglutinin (DBA), Sophora japonica agglutinin (SJA), and Erythrina cristagalli lectin (ECL) stained secretory granules and the organelles in the olfactory supporting cells and did not stain them in the vomeronasal supporting cells. These results suggest that the glycoconjugate moieties are similar in the vomeronasal and olfactory receptor cells of the Japanese striped snake. PMID:20597100

  17. Molecular and neuronal homology between the olfactory systems of zebrafish and mouse

    PubMed Central

    Saraiva, Luis R.; Ahuja, Gaurav; Ivandic, Ivan; Syed, Adnan S.; Marioni, John C.; Korsching, Sigrun I.; Logan, Darren W.

    2015-01-01

    Studies of the two major olfactory organs of rodents, the olfactory mucosa (OM) and the vomeronasal organ (VNO), unraveled the molecular basis of smell in vertebrates. However, some vertebrates lack a VNO. Here we generated and analyzed the olfactory transcriptome of the zebrafish and compared it to the olfactory transcriptomes of mouse to investigate the evolutionary and molecular relationship between single and dual olfactory systems. Our analyses revealed a high degree of molecular conservation, with orthologs of mouse olfactory cell-specific markers and all but one of their chemosensory receptor classes expressed in the single zebrafish olfactory organ. Zebrafish chemosensory receptor genes are expressed across a large dynamic range and their RNA abundance correlates positively with the number of neurons expressing that RNA. Thus we estimate the relative proportions of neuronal sub-types expressing different chemosensory receptors. Receptor repertoire size drives the absolute abundance of different classes of neurons, but we find similar underlying patterns in both species. Finally, we identified novel marker genes that characterize rare neuronal populations in both mouse and zebrafish. In sum, we find that the molecular and cellular mechanisms underpinning olfaction in teleosts and mammals are similar despite 430 million years of evolutionary divergence. PMID:26108469

  18. Attention and Olfactory Consciousness

    PubMed Central

    Keller, Andreas

    2011-01-01

    Understanding the relation between attention and consciousness is an important part of our understanding of consciousness. Attention, unlike consciousness, can be systematically manipulated in psychophysical experiments and a law-like relation between attention and consciousness is waiting to be discovered. Most attempts to discover the nature of this relation are focused on a special type of attention: spatial visual attention. In this review I want to introduce another type of attention to the discussion: attention to the olfactory modality. I will first clarify the position of attention to smells in a general taxonomy of attention. I will then review the mechanisms and neuroanatomy of attention and consciousness in the olfactory system before using the newly introduced system to provide evidence that attention is necessary for consciousness. PMID:22203813

  19. Recent Trend in Development of Olfactory Displays

    NASA Astrophysics Data System (ADS)

    Yanagida, Yasuyuki

    An olfactory display is a device that generates scented air with desired concentration of aroma, and delivers it to the user's olfactory organ. In this article, the nature of olfaction is briefly described from the view point of how to configure olfactory displays. Next, component technologies to compose olfactory displays, i.e., making scents and delivering scents, are categorized. Several existing olfactory display systems are introduced to show the current status of research and development of olfactory displays.

  20. Differential Muscarinic Modulation in the Olfactory Bulb

    PubMed Central

    Smith, Richard S.; Hu, Ruilong; DeSouza, Andre; Eberly, Christian L.; Krahe, Krista; Chan, Wilson

    2015-01-01

    Neuromodulation of olfactory circuits by acetylcholine (ACh) plays an important role in odor discrimination and learning. Early processing of chemosensory signals occurs in two functionally and anatomically distinct regions, the main and accessory olfactory bulbs (MOB and AOB), which receive extensive cholinergic input from the basal forebrain. Here, we explore the regulation of AOB and MOB circuits by ACh, and how cholinergic modulation influences olfactory-mediated behaviors in mice. Surprisingly, despite the presence of a conserved circuit, activation of muscarinic ACh receptors revealed marked differences in cholinergic modulation of output neurons: excitation in the AOB and inhibition in the MOB. Granule cells (GCs), the most abundant intrinsic neuron in the OB, also exhibited a complex muscarinic response. While GCs in the AOB were excited, MOB GCs exhibited a dual muscarinic action in the form of a hyperpolarization and an increase in excitability uncovered by cell depolarization. Furthermore, ACh influenced the input–output relationship of mitral cells in the AOB and MOB differently showing a net effect on gain in mitral cells of the MOB, but not in the AOB. Interestingly, despite the striking differences in neuromodulatory actions on output neurons, chemogenetic inhibition of cholinergic neurons produced similar perturbations in olfactory behaviors mediated by these two regions. Decreasing ACh in the OB disrupted the natural discrimination of molecularly related odors and the natural investigation of odors associated with social behaviors. Thus, the distinct neuromodulation by ACh in these circuits could underlie different solutions to the processing of general odors and semiochemicals, and the diverse olfactory behaviors they trigger. SIGNIFICANCE STATEMENT State-dependent cholinergic modulation of brain circuits is critical for several high-level cognitive functions, including attention and memory. Here, we provide new evidence that cholinergic

  1. Effects of cadmium on olfactory mediated behaviors and molecular biomarkers in coho salmon (Oncorhynchus kisutch).

    PubMed

    Williams, Chase R; Gallagher, Evan P

    2013-09-15

    The olfactory system of salmonids is sensitive to the adverse effects of metals such as copper and cadmium. In the current study, we analyzed olfactory-mediated alarm responses, epithelial injury and recovery, and a suite of olfactory molecular biomarkers encoding genes critical in maintaining olfactory function in juvenile coho salmon receiving acute exposures to cadmium (Cd). The molecular biomarkers analyzed included four G-protein coupled receptors (GPCRs) representing the two major classes of odorant receptors (salmon olfactory receptor sorb and vomeronasal receptors svra, svrb, and gpr27), as well as markers of neurite outgrowth (nrn1) and antioxidant responses to metals, including heme oxygenase 1 (hmox1), and peroxiredoxin 1 (prdx1). Coho received acute (8-168 h) exposures to 3.7 ppb and 347 ppb Cd, and a subset of fish was analyzed following a 16-day depuration. Coho exposed to 347 ppb Cd over 48 h exhibited a reduction in freeze responses, and an extensive loss of olfaction accompanied by histological injury to the olfactory epithelium. The olfactory injury in coho exposed to 347 ppb Cd was accompanied at the gene level by significant decreases in expression of the olfactory GPCRs and increased expression of hmox1. Persistent behavioral deficits, histological injury and altered expression of a subset of olfactory biomarkers were still evident in Cd-exposed coho following a 16-day depuration in clean water. Exposure to 3.7 ppb Cd also resulted in reduced freeze responses and histological changes to the olfactory epithelium within 48 h of Cd exposure, although the extent of olfactory injury was less severe than observed for fish in the high dose Cd group. Furthermore adverse behavioral effects were present in some coho receiving the low dose of Cd following a 16-day depuration. In summary, acute exposures to environmental levels of Cd can cause olfactory injury in coho salmon that may persist following depuration. Mechanism-based biomarkers of oxidative

  2. Effects of cadmium on olfactory mediated behaviors and molecular biomarkers in coho salmon (Oncorhynchus kisutch)

    PubMed Central

    Williams, Chase R.; Gallagher, Evan P.

    2013-01-01

    The olfactory system of salmonids is sensitive to the adverse effects of metals such as copper and cadmium. In the current study, we analyzed olfactory-mediated alarm responses, epithelial injury and recovery, and a suite of olfactory molecular biomarkers encoding genes critical in maintaining olfactory function in juvenile coho salmon receiving acute exposures to cadmium (Cd). The molecular biomarkers analyzed included four G-protein coupled receptors (GPCRs) representing the two major classes of odorant receptors (salmon olfactory receptor sorb and vomeronasal receptors svra, svrb, and gpr27), as well as markers of neurite outgrowth (nrn1) and antioxidant responses to metals, including heme oxygenase 1 (hmox1), and peroxiredoxin 1 (prdx1). Coho received acute (8–168 hr) exposures to 3.7 ppb and 347 ppb Cd, and a subset of fish was analyzed following a 16-day depuration. Coho exposed to 347 ppb Cd over 48 hrs exhibited a reduction in freeze responses, and an extensive loss of olfaction accompanied by histological injury to the olfactory epithelium. The olfactory injury in coho exposed to 347 ppb Cd was accompanied at the gene level by significant decreases in expression of the olfactory GPCRs and increased expression of hmox1. Persistent behavioral deficits, histological injury and altered expression of a subset of olfactory biomarkers were still evident in Cd-exposed coho following a 16-day depuration in clean water. Exposure to 3.7 ppb Cd also resulted in reduced freeze responses and histological changes to the olfactory epithelium within 48 hrs of Cd exposure, although the extent of olfactory injury was less severe than observed for fish in the high dose Cd group. Furthermore adverse behavioral effects were present in some coho receiving the low dose of Cd following a 16-day depuration. In summary, acute exposures to environmental levels of Cd can cause olfactory injury in coho salmon that may persist following depuration. Mechanism-based biomarkers of

  3. Identification and Comparison of Candidate Olfactory Genes in the Olfactory and Non-Olfactory Organs of Elm Pest Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) Based on Transcriptome Analysis

    PubMed Central

    Wang, Yinliang; Chen, Qi; Zhao, Hanbo; Ren, Bingzhong

    2016-01-01

    The leaf beetle Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) is a predominant forest pest that causes substantial damage to the lumber industry and city management. However, no effective and environmentally friendly chemical method has been discovered to control this pest. Until recently, the molecular basis of the olfactory system in A. quadriimpressum was completely unknown. In this study, antennae and leg transcriptomes were analyzed and compared using deep sequencing data to identify the olfactory genes in A. quadriimpressum. Moreover, the expression profiles of both male and female candidate olfactory genes were analyzed and validated by bioinformatics, motif analysis, homology analysis, semi-quantitative RT-PCR and RT-qPCR experiments in antennal and non-olfactory organs to explore the candidate olfactory genes that might play key roles in the life cycle of A. quadriimpressum. As a result, approximately 102.9 million and 97.3 million clean reads were obtained from the libraries created from the antennas and legs, respectively. Annotation led to 34344 Unigenes, which were matched to known proteins. Annotation data revealed that the number of genes in antenna with binding functions and receptor activity was greater than that of legs. Furthermore, many pathway genes were differentially expressed in the two organs. Sixteen candidate odorant binding proteins (OBPs), 10 chemosensory proteins (CSPs), 34 odorant receptors (ORs), 20 inotropic receptors [1] and 2 sensory neuron membrane proteins (SNMPs) and their isoforms were identified. Additionally, 15 OBPs, 9 CSPs, 18 ORs, 6 IRs and 2 SNMPs were predicted to be complete ORFs. Using RT-PCR, RT-qPCR and homology analysis, AquaOBP1/2/4/7/C1/C6, AquaCSP3/9, AquaOR8/9/10/14/15/18/20/26/29/33, AquaIR8a/13/25a showed olfactory-specific expression, indicating that these genes might play a key role in olfaction-related behaviors in A. quadriimpressum such as foraging and seeking. AquaOBP4/C5, AquaOBP4/C5, AquaCSP7

  4. Evolutionary Genomics of Genes Involved in Olfactory Behavior in the Drosophila melanogaster Species Group

    PubMed Central

    Lavagnino, Nicolás; Serra, François; Arbiza, Leonardo; Dopazo, Hernán; Hasson, Esteban

    2012-01-01

    Previous comparative genomic studies of genes involved in olfactory behavior in Drosophila focused only on particular gene families such as odorant receptor and/or odorant binding proteins. However, olfactory behavior has a complex genetic architecture that is orchestrated by many interacting genes. In this paper, we present a comparative genomic study of olfactory behavior in Drosophila including an extended set of genes known to affect olfactory behavior. We took advantage of the recent burst of whole genome sequences and the development of powerful statistical tools to analyze genomic data and test evolutionary and functional hypotheses of olfactory genes in the six species of the Drosophila melanogaster species group for which whole genome sequences are available. Our study reveals widespread purifying selection and limited incidence of positive selection on olfactory genes. We show that the pace of evolution of olfactory genes is mostly independent of the life cycle stage, and of the number of life cycle stages, in which they participate in olfaction. However, we detected a relationship between evolutionary rates and the position that the gene products occupy in the olfactory system, genes occupying central positions tend to be more constrained than peripheral genes. Finally, we demonstrate that specialization to one host does not seem to be associated with bursts of adaptive evolution in olfactory genes in D. sechellia and D. erecta, the two specialists species analyzed, but rather different lineages have idiosyncratic evolutionary histories in which both historical and ecological factors have been involved. PMID:22346339

  5. Light and transmission electron microscopy study of the peripheral olfactory organ of the guppy, Poecilia reticulata (Teleostei, Poecilidae).

    PubMed

    Lazzari, Maurizio; Bettini, Simone; Ciani, Franco; Franceschini, Valeria

    2007-09-01

    A study of the peripheral olfactory organ, with special attention to the olfactory epithelium, has been carried out in the guppy (Poecilia reticulata). Guppy is well known to have a vision-based sexual behavior. The olfactory chamber caudally opens directly in an accessory nasal sac, which is bent medially and gives rise to two recesses that can be considered secondary accessory nasal sacs, antero-medial and postero-medial, respectively. The sensory epithelium, which lines only the medial wall of the nasal cavity, is basically flat rising in a very low lamella only in the posterior part. The olfactory receptors are not evenly distributed in the olfactory mucosa, but aggregate in shallow folds separated by epithelial cells with evident microridges. Ciliated olfactory sensory neurons and microvillous olfactory sensory neurons are clearly identified by transmission electron microscopy (TEM). Scarce crypt olfactory neurons are found throughout the sensory folds. The nasal sacs indicates the capacity to regulate the flow of odorant molecules over the sensory epithelium, possibly through a pump-like mechanism associated with gill ventilation. The organization of the olfactory organ in guppy is simple and reminds what is found in early posthatching stages of fish which at the adult state have a well developed olfactory organ. This simple organization supports the idea that the guppy rely on olfaction less than other fish species provided with more extended olfactory receptorial surface.

  6. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium.

    PubMed

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-09-15

    When olfactory receptor neurons respond to odours, a depolarizing Cl(-) efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl(-) against an electrochemical gradient. In isolated olfactory receptor neurons, the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 is essential for Cl(-) accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl(-) efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl(-) accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl(-) transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl(-) transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl(-) transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl(-)/HCO(3)(-) exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na(+)-Cl(-) cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl(-)/HCO(3)(-) exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl(-) component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl(-) accumulation in olfactory receptor neurons.

  7. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium

    PubMed Central

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-01-01

    When olfactory receptor neurons respond to odours, a depolarizing Cl− efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl− against an electrochemical gradient. In isolated olfactory receptor neurons, the Na+–K+–2Cl− cotransporter NKCC1 is essential for Cl− accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl− efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl− accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl− transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl− transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl− transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl−/HCO3− exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na+–Cl− cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl−/HCO3− exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl− component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl− accumulation in olfactory receptor neurons. PMID:17656441

  8. Human male superiority in olfactory sensitivity to the sperm attractant odorant bourgeonal.

    PubMed

    Olsson, Peter; Laska, Matthias

    2010-06-01

    Recent studies have shown that sperm chemotaxis critically involves the human olfactory receptor OR1D2, which is activated by the aromatic aldehyde bourgeonal. Given that both natural and sexual selection may act upon the expression of receptors, we hypothesized that human males are more sensitive than human females for bourgeonal. Using a 3-alternative forced-choice test procedure, olfactory detection thresholds were determined for a total of 500 subjects, 250 males, and 250 females between 18 and 40 years of age. We found that male subjects detected bourgeonal at significantly lower concentrations (mean value: 13 ppb) compared with female subjects (mean value: 26 ppb), whereas no such gender difference in olfactory sensitivity was found with helional, a structural analog of bourgeonal, and with n-pentyl acetate, an aliphatic ester, which were tested in parallel. Males and females did not differ in their frequency of specific anosmia for any of the 3 odorants. The frequency distributions of olfactory detection thresholds were monomodal with all 3 odorants in both genders. Olfactory detection thresholds did not differ significantly between pre- and postovulatory females with any of the 3 odorants. To the best of our knowledge, this is the first study ever to find a human male superiority in olfactory sensitivity. Single nucleotide polymorphisms and/or copy number variations in genes coding for olfactory receptors may be the proximate cause for our finding, whereas a gender difference in the behavioral relevance of bourgeonal may be the ultimate cause. PMID:20378596

  9. [Eosinophilic colitis. A report of two cases with non conventional treatment].

    PubMed

    Rosas Vargas, Miguel A; Moncayo Coello, Vivian; García Cárdenas, Eustorgio; Valencia Mayoral, Pedro; Sienra Monge, Juan José Luis; del Río Navarro, Blanca E

    2004-01-01

    Eosinophilic colitis is a rare entity of unknown etiology characterized by diarrhea, abdominal pain, and gastrointestinal bleeding. Diagnosis includes histopathological infiltration of more than 20 eosinophils in colon. It is frequently associated with milk hypersensitivity and, less usual, with other foods and increased IgE. Histopthological appearance of eosinophil mediators has been observed in the gut. It is sometimes related to the degree of infiltration of eosinophils in the gut as well as to the disease severity. There is not an established treatment for this entity, although systemic steroids have been used with certain efficacy. However, there is a recurrence of the symptoms when the therapy stops, besides the well known side effects of the long-term use of steroids. Cromolyn inhibits mast cell degranulation and prevents liberation of mediators. It is successful in certain cases, specially the severe ones. However, it is not available for its use in our country. Ketotifen, as last resource in our patients with bad response to habitual treatment and restriction diet, was used. Although its use is controversial, we consider that stabilizing mast cell membrane with subsequent inhibition of degranulation and recruitment of eosinophils to sites of inflammation, would also restrain histamine liberation and blockage of H1 receptors, which would diminish local damage induced by eosinophils. Nonetheless ketotifen mechanism of action is unknown, our patients improved after treatment with this drug.

  10. Olfactory system oscillations across phyla

    PubMed Central

    Kay, Leslie M.

    2014-01-01

    Neural oscillations are ubiquitous in olfactory systems of mammals, insects and molluscs. Neurophysiological and computational investigations point to common mechanisms for gamma or odor associated oscillations across phyla (40–100 Hz in mammals, 20–30 Hz in insects, 0.5–1.5 Hz in molluscs), engaging the reciprocal dendrodendritic synapse between excitatory principle neurons and inhibitory interneurons in the olfactory bulb, antennal lobe, or procerebrum. Recent studies suggest important mechanisms that may modulate gamma oscillations, including neuromodulators and centrifugal input to the olfactory bulb and antennal lobe. Beta (20 Hz) and theta (2–12 Hz) oscillations coordinate activity within and across brain regions. Olfactory beta oscillations are associated with odor learning and depend on centrifugal olfactory bulb input, while theta oscillations are strongly associated with respiration. PMID:25460070

  11. Visual arrestins in olfactory pathways of Drosophila and the malaria vector mosquito Anopheles gambiae

    PubMed Central

    Merrill, C. E.; Riesgo-Escovar, J.; Pitts, R. J.; Kafatos, F. C.; Carlson, J. R.; Zwiebel, L. J.

    2002-01-01

    Arrestins are important components for desensitization of G protein-coupled receptor cascades that mediate neurotransmission as well as olfactory and visual sensory reception. We have isolated AgArr1, an arrestin-encoding cDNA from the malaria vector mosquito, Anopheles gambiae, where olfaction is critical for vectorial capacity. Analysis of AgArr1 expression revealed an overlap between chemosensory and photoreceptor neurons. Furthermore, an examination of previously identified arrestins from Drosophila melanogaster exposed similar bimodal expression, and Drosophila arrestin mutants demonstrate impaired electrophysiological responses to olfactory stimuli. Thus, we show that arrestins in Drosophila are required for normal olfactory physiology in addition to their previously described role in visual signaling. These findings suggest that individual arrestins function in both olfactory and visual pathways in Dipteran insects; these genes may prove useful in the design of control strategies that target olfactory-dependent behaviors of insect disease vectors. PMID:11792843

  12. Genetic architecture of olfactory behavior in Drosophila melanogaster: differences and similarities across development

    PubMed Central

    Lavagnino, N.J.; Arya, G.H.; Korovaichuk, A.; Fanara, J.J.

    2013-01-01

    In the holometabolous insect Drosophila melanogaster, genetic, physiological and anatomical aspects of olfaction are well known in the adult stage, while larval stages olfactory behavior has received some attention it has been less studied than its adult counterpart. Most of these studies focus on olfactory receptors (Or) genes that produce peripheral odor recognition. In this paper, through a loss-of-function screen using P-element inserted lines and also by means of expression analyses of larval olfaction candidate genes, we extended the uncovering of the genetic underpinnings of D. melanogaster larval olfactory behavior by demonstrating that larval olfactory behavior is, in addition to Or genes, orchestrated by numerous genes with diverse functions. Also, our results points out that the genetic architecture of olfactory behavior in D. melanogaster presents a dynamic and changing organization across environments and ontogeny. PMID:23563598

  13. DSL-Notch signaling in the Drosophila brain in response to olfactory stimulation.

    PubMed

    Lieber, Toby; Kidd, Simon; Struhl, Gary

    2011-02-10

    Delta/Serrate/Lag2 (DSL) ligands and their Notch family receptors have profound and pervasive roles in development. They are also expressed in adult tissues, notably in mature neurons and glia in the brain, where their roles are unknown. Here, focusing on the sense of smell in adult Drosophila, we show that Notch is activated in select olfactory receptor neurons (ORNs) in an odorant-specific fashion. This response requires olfactory receptor activity and the Notch ligand Delta. We present evidence that Notch activation depends on synaptic transmission by the ORNs in which the receptors are active and is modulated by the activity of local interneurons in the antennal lobe. It is also subject to regulatory inputs from olfactory receptor activity in other ORNs. These findings identify a correlate of stimulus-dependent brain activity and potentially new forms of neural integration and plasticity.

  14. Phylogenic studies on the olfactory system in vertebrates.

    PubMed

    Taniguchi, Kazuyuki; Taniguchi, Kazumi

    2014-06-01

    The olfactory receptor organs and their primary centers are classified into several types. The receptor organs are divided into fish-type olfactory epithelium (OE), mammal-type OE, middle chamber epithelium (MCE), lower chamber epithelium (LCE), recess epithelium, septal olfactory organ of Masera (SO), mammal-type vomeronasal organ (VNO) and snake-type VNO. The fish-type OE is observed in flatfish and lungfish, while the mammal-type OE is observed in amphibians, reptiles, birds and mammals. The MCE and LCE are unique to Xenopus and turtles, respectively. The recess epithelium is unique to lungfish. The SO is observed only in mammals. The mammal-type VNO is widely observed in amphibians, lizards and mammals, while the snake-type VNO is unique to snakes. The VNO itself is absent in turtles and birds. The mammal-type OE, MCE, LCE and recess epithelium seem to be descendants of the fish-type OE that is derived from the putative primitive OE. The VNO may be derived from the recess epithelium or fish-type OE and differentiate into the mammal-type VNO and snake-type VNO. The primary olfactory centers are divided into mammal-type main olfactory bulbs (MOB), fish-type MOB and mammal-type accessory olfactory bulbs (AOB). The mammal-type MOB first appears in amphibians and succeeds to reptiles, birds and mammals. The fish-type MOB, which is unique to fish, may be the ancestor of the mammal-type MOB. The mammal-type AOB is observed in amphibians, lizards, snakes and mammals and may be the remnant of the fish-type MOB.

  15. Phylogenic Studies on the Olfactory System in Vertebrates

    PubMed Central

    TANIGUCHI, Kazuyuki; TANIGUCHI, Kazumi

    2014-01-01

    ABSTRACT The olfactory receptor organs and their primary centers are classified into several types. The receptor organs are divided into fish-type olfactory epithelium (OE), mammal-type OE, middle chamber epithelium (MCE), lower chamber epithelium (LCE), recess epithelium, septal olfactory organ of Masera (SO), mammal-type vomeronasal organ (VNO) and snake-type VNO. The fish-type OE is observed in flatfish and lungfish, while the mammal-type OE is observed in amphibians, reptiles, birds and mammals. The MCE and LCE are unique to Xenopus and turtles, respectively. The recess epithelium is unique to lungfish. The SO is observed only in mammals. The mammal-type VNO is widely observed in amphibians, lizards and mammals, while the snake-type VNO is unique to snakes. The VNO itself is absent in turtles and birds. The mammal-type OE, MCE, LCE and recess epithelium seem to be descendants of the fish-type OE that is derived from the putative primitive OE. The VNO may be derived from the recess epithelium or fish-type OE and differentiate into the mammal-type VNO and snake-type VNO. The primary olfactory centers are divided into mammal-type main olfactory bulbs (MOB), fish-type MOB and mammal-type accessory olfactory bulbs (AOB). The mammal-type MOB first appears in amphibians and succeeds to reptiles, birds and mammals. The fish-type MOB, which is unique to fish, may be the ancestor of the mammal-type MOB. The mammal-type AOB is observed in amphibians, lizards, snakes and mammals and may be the remnant of the fish-type MOB. PMID:24531771

  16. Electrophysiological differentiation of new neurons in the olfactory bulb.

    PubMed

    Belluzzi, Ottorino; Benedusi, Mascia; Ackman, James; LoTurco, Joseph J

    2003-11-12

    The subventricular zone produces neuroblasts that migrate to the olfactory bulb (OB) and differentiate into interneurons throughout postnatal life (Altman and Das, 1966; Hinds, 1968; Altman, 1969; Kishi et al., 1990; Luskin, 1993; Lois and Alvarez-Buylla, 1994). Although such postnatally generated interneurons have been characterized morphologically, their physiological differentiation has not been thoroughly described. Combining retroviral-mediated labeling of newly generated neurons with patch-clamp electrophysiology, we demonstrated that soon after new cells enter the layers of the olfactory bulb, they display voltage-dependent currents typical of more mature neurons. We also show that these "newcomers" express functional GABA and glutamate receptor channels, respond synaptically to stimulation of the olfactory nerve, and may establish both axodendritic and dendrodendritic synaptic contacts within the olfactory bulb. These data provide a basic description of the physiology of newly generated cells in the OB and show that such new cells are functional neurons that synaptically integrate into olfactory bulb circuitry soon after their arrival.

  17. Glycosylation patterns are sexually dimorphic throughout development of the olfactory system in Manduca sexta.

    PubMed

    Gibson, Nicholas J; Hildebrand, John G; Tolbert, Leslie P

    2004-08-01

    In the moth Manduca sexta, development of the adult olfactory system depends on complex interactions between olfactory receptor neurons in the antenna, antennal-lobe neurons in the brain, and several classes of glial cells. As one approach to characterizing molecules that may play roles in these interactions, we used lectins to screen antennae and antennal lobes at different stages of adult development. We find that each of the major neural cell types has a distinct pattern of labeling by lectins. Effects of enzymatic and other treatments on lectin labeling lead us to conclude that the predominant lectin ligands are: glycosphingolipids and an O-linked, fucose-containing glycoprotein on axons of olfactory receptor neurons, O-linked glycoproteins on antennal-lobe neurons, and N-linked glycoproteins on all classes of glial cells in the primary olfactory pathway. Wheat germ agglutinin labels all olfactory axons uniformly during much of development, but labeling becomes restricted to the pheromone-responsive olfactory receptor neurons in the adult male. Succinylated WGA reveals differences in these axon classes earlier, as glomerului develop from protoglomeruli. The adult female displays a less pronounced difference in labeling of axons targeting ordinary and sexually dimorphic glomeruli. Differences in labeling of receptor axons targeted to ordinary and sexually dimorphic glomeruli may be correlated with differences in function or connectivity in different regions of the antennal lobe.

  18. Chronic restricted access to food leading to undernutrition affects rat neuroendocrine status and olfactory-driven behaviors.

    PubMed

    Badonnel, Karine; Lacroix, Marie-Christine; Monnerie, Régine; Durieux, Didier; Caillol, Monique; Baly, Christine

    2012-07-01

    Previous studies have demonstrated that olfactory-driven behaviors in rats are influenced by short-term caloric restriction, partly through the modulation of olfactory sensitivity by appetite-modulating hormones or peptides such as insulin and leptin. Here, we addressed the issue of a long-term modulation of their neuroendocrine status by evaluating the effect of chronic food restriction in rats following a limitation of the duration of daily food intake to 2 h (SF) instead of 8 h (LF) on the expression of insulin and leptin system in the olfactory mucosa and bulb and on olfactory behaviors. This restriction resulted in a one-third reduction in the daily food intake and a 25% reduction in the body weight of SF rats when compared to controls, and was accompanied by lower levels of triglycerides, glucose, insulin and leptin in SF rats. Under these conditions, we observed a modulation of olfactory-mediated behaviors regarding food odors. In addition, restriction had a differential effect on the expression of insulin receptors, but not that of leptin receptors, in the olfactory mucosa, whereas no transcriptional change was observed at the upper level of the olfactory bulb. Overall, these data demonstrated that long-term changes in nutritional status modulate olfactory-mediated behaviors. Modulation of insulin system expression in the olfactory mucosa of food restricted rats suggests that this hormone could be part of this process.

  19. An endocannabinoid system is present in the mouse olfactory epithelium but does not modulate olfaction

    PubMed Central

    Hutch, Chelsea; Hillard, Cecilia J.; Jia, Cuihong; Hegg, Colleen C.

    2015-01-01

    Endocannabinoids modulate a diverse array of functions including progenitor cell proliferation in the central nervous system, and odorant detection and food intake in the mammalian central olfactory system and larval Xenopus laevis peripheral olfactory system. However, the presence and role of endocannabinoids in the peripheral olfactory epithelium has not been examined in mammals. We found the presence of cannabinoid type 1 (CB1) and cannabinoid type 2 (CB2) receptor protein and mRNA in the olfactory epithelium. Using either immunohistochemistry or calcium imaging we localized CB1 receptors on neurons, glia like sustentacular cells, microvillous cells and progenitor-like basal cells. To examine the role of endocannabinoids, CB1 and CB2 receptor deficient (CB1−/−/CB2−/−) mice were used. The endocannabinoid 2-arachidonylglycerol (2-AG) was present at high levels in both C57BL/6 wildtype and CB1−/−/CB2−/− mice. 2-AG synthetic and degradative enzymes are expressed in wildtype mice. A small but significant decrease in basal cell and olfactory sensory neuron numbers was observed in CB1−/−/CB2−/− mice compared to wildtype mice. The decrease in olfactory sensory neurons did not translate to impairment in olfactory-mediated behaviors assessed by the buried food test and habituation/dishabituation test. Collectively, these data indicate the presence of an endocannabinoid system in the mouse olfactory epithelium. However, unlike in tadpoles, endocannabinoids do not modulate olfaction. Further investigation on the role of endocannabinoids in progenitor cell function in the olfactory epithelium is warranted. PMID:26037800

  20. Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size.

    PubMed

    Morrison, Filomene G; Dias, Brian G; Ressler, Kerry J

    2015-10-13

    Although much work has investigated the contribution of brain regions such as the amygdala, hippocampus, and prefrontal cortex to the processing of fear learning and memory, fewer studies have examined the role of sensory systems, in particular the olfactory system, in the detection and perception of cues involved in learning and memory. The primary sensory receptive field maps of the olfactory system are exquisitely organized and respond dynamically to cues in the environment, remaining plastic from development through adulthood. We have previously demonstrated that olfactory fear conditioning leads to increased odorant-specific receptor representation in the main olfactory epithelium and in glomeruli within the olfactory bulb. We now demonstrate that olfactory extinction training specific to the conditioned odor stimulus reverses the conditioning-associated freezing behavior and odor learning-induced structural changes in the olfactory epithelium and olfactory bulb in an odorant ligand-specific manner. These data suggest that learning-induced freezing behavior, structural alterations, and enhanced neural sensory representation can be reversed in adult mice following extinction training.

  1. Probing Formability Improvement of Ultra-thin Ferritic Stainless Steel Bipolar Plate of PEMFC in Non-conventional Forming Process

    NASA Astrophysics Data System (ADS)

    Bong, Hyuk Jong; Barlat, Frédéric; Lee, Myoung-Gyu

    2016-08-01

    Formability increase in non-conventional forming profiles programmed in the servo-press was investigated using finite element analysis. As an application, forming experiment on a 0.15-mm-thick ferritic stainless steel sheet for a bipolar plate, a primary component of a proton exchange membrane fuel cell, was conducted. Four different forming profiles were considered to investigate the effects of forming profiles on formability and shape accuracy. The four motions included conventional V motion, holding motion, W motion, and oscillating motion. Among the four motions, the holding motion, in which the slide was held for a certain period at the bottom dead point, led to the best formability. Finite element simulations were conducted to validate the experimental results and to probe the formability improvement in the non-conventional forming profiles. A creep model to address stress relaxation effect along with tool elastic recovery was implemented using a user-material subroutine, CREEP in ABAQUS finite element software. The stress relaxation and variable contact conditions during the holding and oscillating profiles were found to be the main mechanism of formability improvement.

  2. Neuropeptide feedback modifies odor-evoked dynamics in C. elegans olfactory neurons

    PubMed Central

    Chalasani, Sreekanth H.; Kato, Saul; Albrecht, Dirk R.; Nakagawa, Takao; Abbott, L. F.; Bargmann, Cornelia I.

    2010-01-01

    Many neurons release classical transmitters together with neuropeptide cotransmitters whose functions are incompletely understood. Here we define the relationship between two transmitters in the olfactory system of Caenorhabditis elegans, showing that a neuropeptide-to-neuropeptide feedback loop alters sensory dynamics in primary olfactory neurons. The AWC olfactory neuron is glutamatergic and also expresses the peptide NLP-1. nlp-1 mutants have increased AWC-dependent behaviors, suggesting that NLP-1 limits the normal response. The receptor for NLP-1 is the G protein-coupled receptor NPR-11, which acts in postsynaptic AIA interneurons. Feedback from AIA interneurons modulates odor-evoked calcium dynamics in AWC olfactory neurons and requires INS-1, a neuropeptide released from AIA. The neuropeptide feedback loop dampens behavioral responses to odors on short and long timescales. Our results point to neuronal dynamics as a site of behavioral regulation and reveal the ability of neuropeptide feedback to remodel sensory networks on multiple timescales. PMID:20364145

  3. Combinatorial Rules of Precursor Specification Underlying Olfactory Neuron Diversity

    PubMed Central

    Li, Qingyun; Ha, Tal Soo; Okuwa, Sumie; Wang, Yiping; Wang, Qian; Millard, S. Sean; Smith, Dean P.; Volkan, Pelin Cayirlioglu

    2015-01-01

    Summary Background Sensory neuron diversity ensures optimal detection of the external world and is a hallmark of sensory systems. An extreme example is the olfactory system, as individual olfactory receptor neurons (ORNs) adopt unique sensory identities by typically expressing a single receptor gene from a large genomic repertoire. In Drosophila, about 50 different ORN classes are generated from a field of precursor cells, giving rise to spatially restricted and distinct clusters of ORNs on the olfactory appendages. Developmental strategies spawning ORN diversity from an initially homogeneous population of precursors are largely unknown. Results Here we unravel the nested and binary logic of the combinatorial code that patterns the decision landscape of precursor states underlying ORN diversity in the Drosophila olfactory system. The transcription factor Rotund (Rn) is a critical component of this code that is expressed in a subset of ORN precursors. Addition of Rn to preexisting transcription factors that assign zonal identities to precursors on the antenna subdivides each zone and almost exponentially increases ORN diversity by branching off novel precursor fates from default ones within each zone. In rn mutants, rn-positive ORN classes are converted to rn-negative ones in a zone-specific manner. Conclusions We provide a model describing how nested and binary changes in combinations of transcription factors could coordinate and pattern a large number of distinct precursor identities within a population to modulate the level of ORN diversity during development and evolution. PMID:24268416

  4. Olfactory function in patients with olfactory groove meningioma

    PubMed Central

    Welge-Luessen, A; Temmel, A; Quint, C; Moll, B; Wolf, S; Hummel, T

    2001-01-01

    OBJECTIVES—Olfactory meningiomas are rare benign tumours and represent about 12% of all basal meningiomas. Anosmia is thought to be among the first symptoms, even though patients often present with headaches or visual problems. However, so far no detailed physophysical tests of olfactory function have been performed in a large number of those patients.
METHODS—Twelve patients (five men, seven women; mean age 52 years) with olfactory meningiomas were examined. In all patients extensive preoperative and postoperative lateralised olfactory testing was performed using the "Sniffin' Sticks" test battery, a psychometric testing tool. In eight cases the meningioma was lateralised (five left, three right), in four patients a bilateral meningioma was found. In addition to a detailed ear, nose, and throat examination MRI was performed in all patients.
RESULTS—In preoperative testing six patients were found to be anosmic on the side of the tumour, two were hyposmic. Four patients were normosmic. Postoperative investigations showed lateralised anosmia in four patients on the operated side, three were normosmic on the contralateral side and one hyposmic. The remaining eight patients were completely anosmic postoperatively.
CONCLUSIONS—(1) Contrary to expectations, olfactory testing seems to be of little help in detecting olfactory meningiomas. (2) The likelihood of normal postoperative olfactory function contralateral to the tumour was high when the tumour was less than 3 cm in diameter and preoperative normosmia had been established. (3) Preservation of olfactory function ipsilateral to the tumour seems to be extremely difficult, irrespective of tumour size or surgical approach.

 PMID:11160471

  5. Projections from the posterolateral olfactory amygdala to the ventral striatum: neural basis for reinforcing properties of chemical stimuli

    PubMed Central

    Ubeda-Bañon, Isabel; Novejarque, Amparo; Mohedano-Moriano, Alicia; Pro-Sistiaga, Palma; de la Rosa-Prieto, Carlos; Insausti, Ricardo; Martinez-Garcia, Fernando; Lanuza, Enrique; Martinez-Marcos, Alino

    2007-01-01

    Background Vertebrates sense chemical stimuli through the olfactory receptor neurons whose axons project to the main olfactory bulb. The main projections of the olfactory bulb are directed to the olfactory cortex and olfactory amygdala (the anterior and posterolateral cortical amygdalae). The posterolateral cortical amygdaloid nucleus mainly projects to other amygdaloid nuclei; other seemingly minor outputs are directed to the ventral striatum, in particular to the olfactory tubercle and the islands of Calleja. Results Although the olfactory projections have been previously described in the literature, injection of dextran-amines into the rat main olfactory bulb was performed with the aim of delimiting the olfactory tubercle and posterolateral cortical amygdaloid nucleus in our own material. Injection of dextran-amines into the posterolateral cortical amygdaloid nucleus of rats resulted in anterograde labeling in the ventral striatum, in particular in the core of the nucleus accumbens, and in the medial olfactory tubercle including some islands of Calleja and the cell bridges across the ventral pallidum. Injections of Fluoro-Gold into the ventral striatum were performed to allow retrograde confirmation of these projections. Conclusion The present results extend previous descriptions of the posterolateral cortical amygdaloid nucleus efferent projections, which are mainly directed to the core of the nucleus accumbens and the medial olfactory tubercle. Our data indicate that the projection to the core of the nucleus accumbens arises from layer III; the projection to the olfactory tubercle arises from layer II and is much more robust than previously thought. This latter projection is directed to the medial olfactory tubercle including the corresponding islands of Calleja, an area recently described as critical node for the neural circuit of addiction to some stimulant drugs of abuse. PMID:18047654

  6. Intermittency Coding in the Primary Olfactory System: A Neural Substrate for Olfactory Scene Analysis

    PubMed Central

    Park, Il Memming; Bobkov, Yuriy V.; Ache, Barry W.

    2014-01-01

    The spatial and temporal characteristics of the visual and acoustic sensory input are indispensable attributes for animals to perform scene analysis. In contrast, research in olfaction has focused almost exclusively on how the nervous system analyzes the quality and quantity of the sensory signal and largely ignored the spatiotemporal dimension especially in longer time scales. Yet, detailed analyses of the turbulent, intermittent structure of water- and air-borne odor plumes strongly suggest that spatio-temporal information in longer time scales can provide major cues for olfactory scene analysis for animals. We show that a bursting subset of primary olfactory receptor neurons (bORNs) in lobster has the unexpected capacity to encode the temporal properties of intermittent odor signals. Each bORN is tuned to a specific range of stimulus intervals, and collectively bORNs can instantaneously encode a wide spectrum of intermittencies. Our theory argues for the existence of a novel peripheral mechanism for encoding the temporal pattern of odor that potentially serves as a neural substrate for olfactory scene analysis. PMID:24431452

  7. Map Formation in the Olfactory Bulb by Axon Guidance of Olfactory Neurons

    PubMed Central

    Auffarth, Benjamin; Kaplan, Bernhard; Lansner, Anders

    2011-01-01

    The organization of representations in the brain has been observed to locally reflect subspaces of inputs that are relevant to behavioral or perceptual feature combinations, such as in areas receptive to lower and higher-order features in the visual system. The early olfactory system developed highly plastic mechanisms and convergent evidence indicates that projections from primary neurons converge onto the glomerular level of the olfactory bulb (OB) to form a code composed of continuous spatial zones that are differentially active for particular physico-chemical feature combinations, some of which are known to trigger behavioral responses. In a model study of the early human olfactory system, we derive a glomerular organization based on a set of real-world, biologically relevant stimuli, a distribution of receptors that respond each to a set of odorants of similar ranges of molecular properties, and a mechanism of axon guidance based on activity. Apart from demonstrating activity-dependent glomeruli formation and reproducing the relationship of glomerular recruitment with concentration, it is shown that glomerular responses reflect similarities of human odor category perceptions and that further, a spatial code provides a better correlation than a distributed population code. These results are consistent with evidence of functional compartmentalization in the OB and could suggest a function for the bulb in encoding of perceptual dimensions. PMID:22013417

  8. Intermittency coding in the primary olfactory system: a neural substrate for olfactory scene analysis.

    PubMed

    Park, Il Memming; Bobkov, Yuriy V; Ache, Barry W; Príncipe, José C

    2014-01-15

    The spatial and temporal characteristics of the visual and acoustic sensory input are indispensable attributes for animals to perform scene analysis. In contrast, research in olfaction has focused almost exclusively on how the nervous system analyzes the quality and quantity of the sensory signal and largely ignored the spatiotemporal dimension especially in longer time scales. Yet, detailed analyses of the turbulent, intermittent structure of water- and air-borne odor plumes strongly suggest that spatio-temporal information in longer time scales can provide major cues for olfactory scene analysis for animals. We show that a bursting subset of primary olfactory receptor neurons (bORNs) in lobster has the unexpected capacity to encode the temporal properties of intermittent odor signals. Each bORN is tuned to a specific range of stimulus intervals, and collectively bORNs can instantaneously encode a wide spectrum of intermittencies. Our theory argues for the existence of a novel peripheral mechanism for encoding the temporal pattern of odor that potentially serves as a neural substrate for olfactory scene analysis.

  9. Farnesol-Detecting Olfactory Neurons in Drosophila

    PubMed Central

    Ronderos, David S.; Lin, Chun-Chieh; Potter, Christopher J.

    2014-01-01

    We set out to deorphanize a subset of putative Drosophila odorant receptors expressed in trichoid sensilla using a transgenic in vivo misexpression approach. We identified farnesol as a potent and specific activator for the orphan odorant receptor Or83c. Farnesol is an intermediate in juvenile hormone biosynthesis, but is also produced by ripe citrus fruit peels. Here, we show that farnesol stimulates robust activation of Or83c-expressing olfactory neurons, even at high dilutions. The CD36 homolog Snmp1 is required for normal farnesol response kinetics. The neurons expressing Or83c are found in a subset of poorly characterized intermediate sensilla. We show that these neurons mediate attraction behavior to low concentrations of farnesol and that Or83c receptor mutants are defective for this behavior. Or83c neurons innervate the DC3 glomerulus in the antennal lobe and projection neurons relaying information from this glomerulus to higher brain centers target a region of the lateral horn previously implicated in pheromone perception. Our findings identify a sensitive, narrowly tuned receptor that mediates attraction behavior to farnesol and demonstrates an effective approach to deorphanizing odorant receptors expressed in neurons located in intermediate and trichoid sensilla that may not function in the classical “empty basiconic neuron” system. PMID:24623773

  10. Identification of Candidate Olfactory Genes in Chilo suppressalis by Antennal Transcriptome Analysis

    PubMed Central

    Cao, Depan; Liu, Yang; Wei, Jinjin; Liao, Xinyan; Walker, William B.; Li, Jianhong; Wang, Guirong

    2014-01-01

    Antennal olfaction, which is extremely important for insect survival, mediates key behaviors such as host preference, mate choice, and oviposition site selection. In insects, odor detection is mediated by multiple proteins in the antenna, especially the odorant receptors (ORs) and ionotropic receptors (IRs), which ensure the specificity of the olfactory sensory neuron responses. In this study, we identified the olfactory gene repertoire of the rice stem borer, Chilo suppressalis, an economically important agricultural pest, which inflicts great damage to the rice yield in south and east part of Asia, especially in Southern China. By Illumina sequencing of male and female antennal transcriptomes, we identified 47 odorant receptors, 20 ionotropic receptors, 26 odorant binding proteins, 21 chemosensory proteins and 2 sensory neuron membrane proteins. Our findings make it possible for future research of the olfactory system of C. suppressalis at the molecular level. PMID:25076861

  11. Identification of candidate olfactory genes in Chilo suppressalis by antennal transcriptome analysis.

    PubMed

    Cao, Depan; Liu, Yang; Wei, Jinjin; Liao, Xinyan; Walker, William B; Li, Jianhong; Wang, Guirong

    2014-01-01

    Antennal olfaction, which is extremely important for insect survival, mediates key behaviors such as host preference, mate choice, and oviposition site selection. In insects, odor detection is mediated by multiple proteins in the antenna, especially the odorant receptors (ORs) and ionotropic receptors (IRs), which ensure the specificity of the olfactory sensory neuron responses. In this study, we identified the olfactory gene repertoire of the rice stem borer, Chilo suppressalis, an economically important agricultural pest, which inflicts great damage to the rice yield in south and east part of Asia, especially in Southern China. By Illumina sequencing of male and female antennal transcriptomes, we identified 47 odorant receptors, 20 ionotropic receptors, 26 odorant binding proteins, 21 chemosensory proteins and 2 sensory neuron membrane proteins. Our findings make it possible for future research of the olfactory system of C. suppressalis at the molecular level. PMID:25076861

  12. PACAP protects against TNFα-induced cell death in olfactory epithelium and olfactory placodal cell lines

    PubMed Central

    Kanekar, Shami; Gandham, Mahendra; Lucero, Mary T

    2010-01-01

    In mouse olfactory epithelium (OE), pituitary adenylate cyclase activating peptide (PACAP) protects against axotomy-induced apoptosis. We used mouse OE to determine whether PACAP protects neurons during exposure to the inflammatory cytokine TNFα. Live slices of neonatal mouse OE were treated with 40 ng/ml TNFα ± 40 nM PACAP for 6 hours and dying cells were live-labeled with 0.5% propidium iodide. TNFα significantly increased the percentage of dying cells while co-incubation with PACAP prevented cell death. PACAP also prevented TNFα-mediated cell death in the olfactory placodal (OP) cell lines, OP6 and OP27. Although OP cell lines express all three PACAP receptors (PAC1, VPAC1,VPAC2), PACAP’s protection of these cells from TNFα was mimicked by the specific PAC1 receptor agonist maxadilan and abolished by the PAC1 antagonist PACAP6–38. Treatment of OP cell lines with blockers or activators of the PLC and AC/MAPKK pathways revealed that PACAP-mediated protection from TNFα involved both pathways. PACAP may therefore function through PAC1 receptors to protect neurons from cell death during inflammatory cytokine release in vivo as would occur upon viral infection or allergic rhinitis-associated injury. PMID:20654718

  13. Orientation in birds. Olfactory navigation.

    PubMed

    Papi, F

    1991-01-01

    Research work on the olfactory navigation of birds, which has only recently attracted attention, has shown that many wild species rely on an osmotactic mechanism to find food sources, even at a considerable distance. The homing pigeon, the only bird to have been thoroughly investigated with respect to olfactory navigation, has been found to rely on local odours for homeward orientation, and to integrate olfactory cues perceived during passive transportation with those picked up at the release site. It is possible to design experiments in which birds are given false olfactory information, and predictions about the effects of this can be made and tested. Pigeons are able to home from unfamiliar sites because they acquire an olfactory map extending beyond the area they have flown over. The olfactory map is built up by associating wind-borne odours with the direction from which they come; this was shown by experiments which aimed to prevent, limit or alter this association. One aim of the research work has been to test whether pigeons flying over unfamiliar areas also rely or can learn to rely on non-olfactory cues, depending on their local availability, and/or on the methods of rearing and training applied to them. Various evaluations have been made of the results; the most recent experiments, however, confirm that pigeons do derive directional information from atmospheric odours. A neurobiological approach is also in progress; its results show that some telencephalic areas are involved in orientation and olfactory navigation. The lack of any knowledge about the distribution and chemical nature of the odorants which allow pigeons to navigate hinders progress in this area of research.

  14. Evaluation of non-conventional polar modifiers on immobilized chiral stationary phases for improved resolution of enantiomers by supercritical fluid chromatography.

    PubMed

    DaSilva, Jimmy O; Coes, Brandyce; Frey, Lisa; Mergelsberg, Ingrid; McClain, Ray; Nogle, Lisa; Welch, Christopher J

    2014-02-01

    An evaluation of the use of non-conventional polar modifiers for the supercritical fluid chromatographic separation of enantiomers on immobilized chiral stationary phases is presented. The resolution of a group of nine commercially available racemates is studied on the Chiralpak IA, IB, IC, ID, IE, and IF chiral stationary phases using CO2-based eluents containing non-conventional polar modifiers such as dichloromethane, chloroform, tetrahydrofuran, 2-methyl tetrahydrofuran, methyl tert-butyl ether, cyclopentyl methyl ether, acetone, ethyl acetate, toluene, 2,2,2-trifluoroethanol, and N,N-dimethylformamide. Screening experiments and method development for the commercial racemates on the immobilized columns with the non-conventional solvents demonstrated an ability to adjust the retention and improve resolution. From these results we were able to assign a general eluotropic relationship between the non-conventional solvents and methanol. A general ability to selectively adjust chromatographic retention while improving analyte solubility can lead to improved preparative chromatographic performance. PMID:24456706

  15. Understanding smell--the olfactory stimulus problem.

    PubMed

    Auffarth, Benjamin

    2013-09-01

    The main problem with sensory processing is the difficulty in relating sensory input to physiological responses and perception. This is especially problematic at higher levels of processing, where complex cues elicit highly specific responses. In olfaction, this relationship is particularly obfuscated by the difficulty of characterizing stimulus statistics and perception. The core questions in olfaction are hence the so-called stimulus problem, which refers to the understanding of the stimulus, and the structure-activity and structure-odor relationships, which refer to the molecular basis of smell. It is widely accepted that the recognition of odorants by receptors is governed by the detection of physico-chemical properties and that the physical space is highly complex. Not surprisingly, ideas differ about how odor stimuli should be classified and about the very nature of information that the brain extracts from odors. Even though there are many measures for smell, there is none that accurately describes all aspects of it. Here, we summarize recent developments in the understanding of olfaction. We argue that an approach to olfactory function where information processing is emphasized could contribute to a high degree to our understanding of smell as a perceptual phenomenon emerging from neural computations. Further, we argue that combined analysis of the stimulus, biology, physiology, and behavior and perception can provide new insights into olfactory function. We hope that the reader can use this review as a competent guide and overview of research activities in olfactory physiology, psychophysics, computation, and psychology. We propose avenues for research, particularly in the systematic characterization of receptive fields and of perception.

  16. [Occupational olfactory changes: diagnostic trends].

    PubMed

    Chiappino, G; Broich, G; Mascagni, P; Picchi, O

    1998-01-01

    Olfactory testing has been of minor interest in Occupational Health due to the lack of testing methods able to detect malingering. On the other hand there is evidence that occupational exposure to several, mainly neurotoxic, substances may result in olfactory damage. We have combined three different testing methods in one package in order to assure a forensic-degree level of results. The package consists of: 1. primary neuron functionality testing with a single olfactory stimulant; 2. olfactory-trigeminal discrimination testing with regular sniff-test; 3. odor identification score by Doty's UPSIT test. Final judgement of a link between olfactory system impairment and occupational exposure to chemicals requires a good knowledge of the present and past occupational exposure and of the general conditions of the patient. It requires collaboration between the Occupational Health specialist and the expert in Olfactology and may be completed with endoscopy, radiography and other specific controls. We suggest that a more extensive use of appropriate olfactory testing should be established at least for special risk groups of workers. This will not only detect occupational health damage that would otherwise have remained unknown, but can also furnish new information on the neurotoxic effects of many inhalable chemicals. PMID:9847530

  17. Looking for a Person-Centered Medicine: Non Conventional Medicine in the Conventional European and Italian Setting

    PubMed Central

    Roberti di Sarsina, Paolo; Iseppato, Ilaria

    2011-01-01

    In Italy, the use of non conventional medicines (NCMs) is spreading among people as in the rest of Europe. Sales of alternative remedies are growing, and likewise the number of medical doctors (MDs) who practise NCM/complementary and alternative medicine (CAM). However, in Italy as in other countries of the European Union, at the present time the juridical/legal status of NCM/CAM is not well established, mainly due to the lack of any national law regulating NCM/CAM professional training, practice and public supply and the absence of government-promoted scientific research in this field. This is an obstacle to safeguarding the patient's interests and freedom of choice, especially now that dissatisfaction with biomedicine is inclining more and more people to look for a holistic and patient-centered form of medicine. PMID:19505973

  18. Electrophysiological properties of frog olfactory supporting cells.

    PubMed

    Trotier, D

    1998-06-01

    Cells, identified as supporting cells by Lucifer Yellow injection, were recorded from slices of frog olfactory epithelium using patch-clamp recordings. Cell-attached single-channel recordings indicated that the intracellular potential (IP) was -68 +/- 7 mV (n = 22) with 4 mM K+ in the bath ([K+]o). IP was -67 +/- 4 mV (n = 32) in whole-cell conditions with 100 mM KCl inside the cell, suggesting a low membrane permeability for Cl-. IP depended on [K+]o in a manner described by the Goldman-Hodgkin-Katz equation with a permeability ratio pk+:PNa+ of 40. The input resistance was 32 +/- 14 M omega (n = 15), indicating a high membrane conductance at rest. Odorant stimulations evoked passive membrane depolarizations, probably reflecting an increase in [K+]o due to the neuronal activation. Whole-cell recordings with 100 mM CsCl instead of KCl in the pipette, together with the block of gap-junctions with octanol, indicated the existence of an electrical coupling between supporting cells. The electrical coupling between these glial-like cells could facilitate the clearance of K+ ions released by olfactory receptor neurons during odorant stimulation.

  19. A presynaptic gain control mechanism fine-tunes olfactory behavior.

    PubMed

    Root, Cory M; Masuyama, Kaoru; Green, David S; Enell, Lina E; Nässel, Dick R; Lee, Chi-Hon; Wang, Jing W

    2008-07-31

    Early sensory processing can play a critical role in sensing environmental cues. We have investigated the physiological and behavioral function of gain control at the first synapse of olfactory processing in Drosophila. Olfactory receptor neurons (ORNs) express the GABA(B) receptor (GABA(B)R), and its expression expands the dynamic range of ORN synaptic transmission that is preserved in projection neuron responses. Strikingly, each ORN channel has a unique baseline level of GABA(B)R expression. ORNs that sense the aversive odorant CO(2) do not express GABA(B)Rs and do not have significant presynaptic inhibition. In contrast, pheromone-sensing ORNs express a high level of GABA(B)Rs and exhibit strong presynaptic inhibition. Furthermore, pheromone-dependent mate localization is impaired in flies that lack GABA(B)Rs in specific ORNs. These findings indicate that different olfactory receptor channels employ heterogeneous presynaptic gain control as a mechanism to allow an animal's innate behavioral responses to match its ecological needs.

  20. The cyclic nucleotide gated channel subunit CNG-1 instructs behavioral outputs in Caenorhabditis elegans by coincidence detection of nutritional status and olfactory input.

    PubMed

    He, Chao; Altshuler-Keylin, Svetlana; Daniel, David; L'Etoile, Noelle D; O'Halloran, Damien

    2016-10-01

    In mammals, olfactory subsystems have been shown to express seven-transmembrane G-protein-coupled receptors (GPCRs) in a one-receptor-one-neuron pattern, whereas in Caenorhabditis elegans, olfactory sensory neurons express multiple G-protein coupled odorant receptors per olfactory sensory neuron. In both mammalian and C. elegans olfactory sensory neurons (OSNs), the process of olfactory adaptation begins within the OSN; this process of negative feedback within the mammalian OSN has been well described in mammals and enables activated OSNs to desensitize their response cell autonomously while attending to odors detected by separate OSNs. However, the mechanism that enables C. elegans to adapt to one odor and attend to another odor sensed by the same olfactory sensory neuron remains unclear. We found that the cyclic nucleotide gated channel subunit CNG-1 is required to promote cross adaptation responses between distinct olfactory cues. This change in sensitivity to a pair of odorants after persistent stimulation by just one of these odors is modulated by the internal nutritional state of the animal, and we find that this response is maintained across a diverse range of food sources for C. elegans. We also reveal that CNG-1 integrates food related cues for exploratory motor output, revealing that CNG-1 functions in multiple capacities to link nutritional information with behavioral output. Our data describes a novel model whereby CNG channels can integrate the coincidence detection of appetitive and olfactory information to set olfactory preferences and instruct behavioral outputs.

  1. The activity-dependent histone variant H2BE modulates the life span of olfactory neurons

    PubMed Central

    Santoro, Stephen W; Dulac, Catherine

    2012-01-01

    We have identified a replication-independent histone variant, Hist2h2be (referred to herein as H2be), which is expressed exclusively by olfactory chemosensory neurons. Levels of H2BE are heterogeneous among olfactory neurons, but stereotyped according to the identity of the co-expressed olfactory receptor (OR). Gain- and loss-of-function experiments demonstrate that changes in H2be expression affect olfactory function and OR representation in the adult olfactory epithelium. We show that H2BE expression is reduced by sensory activity and that it promotes neuronal cell death, such that inactive olfactory neurons display higher levels of the variant and shorter life spans. Post-translational modifications (PTMs) of H2BE differ from those of the canonical H2B, consistent with a role for H2BE in altering transcription. We propose a physiological function for H2be in modulating olfactory neuron population dynamics to adapt the OR repertoire to the environment. DOI: http://dx.doi.org/10.7554/eLife.00070.001 PMID:23240083

  2. Extracellular potentials recording in intact olfactory epithelium by microelectrode array for a bioelectronic nose.

    PubMed

    Liu, Qingjun; Ye, Weiwei; Xiao, Lidan; Du, Liping; Hu, Ning; Wang, Ping

    2010-06-15

    Human beings and animals have sensitive olfactory systems that can sense and identify a variety of odors. The purpose of this study is to combine biological cells with micro-chips to establish a novel bioelectronic nose system for odor detection by electrophysiological sensing measurements of olfactory tissue. In our experiments, 36-channel microelectrode arrays (MEAs) with the diameter of 30 microm were fabricated on the glass substrate, and olfactory epithelium was stripped from rats and fixed on the surface of MEA. Electrophysiological activities of olfactory receptor neurons in intact epithelium were measured through the multi-channel recording system. The extracellular potentials of cell networks could be effectively analyzed by correlation analysis between different channels. After being stimulated by odorants, such as acetic acid and butanedione, the olfactory cells generate different firing modes. These firing characteristics can be derived by time-domain and frequency-domain analysis, and they were different from spontaneous potentials. The investigation of olfactory epithelium can provide more information of olfactory system for artificial olfaction biomimetic design.

  3. Multi-unit Recording Methods to Characterize Neural Activity in the Locust (Schistocerca Americana) Olfactory Circuits

    PubMed Central

    Saha, Debajit; Leong, Kevin; Katta, Nalin; Raman, Baranidharan

    2013-01-01

    Detection and interpretation of olfactory cues are critical for the survival of many organisms. Remarkably, species across phyla have strikingly similar olfactory systems suggesting that the biological approach to chemical sensing has been optimized over evolutionary time1. In the insect olfactory system, odorants are transduced by olfactory receptor neurons (ORN) in the antenna, which convert chemical stimuli into trains of action potentials. Sensory input from the ORNs is then relayed to the antennal lobe (AL; a structure analogous to the vertebrate olfactory bulb). In the AL, neural representations for odors take the form of spatiotemporal firing patterns distributed across ensembles of principal neurons (PNs; also referred to as projection neurons)2,3. The AL output is subsequently processed by Kenyon cells (KCs) in the downstream mushroom body (MB), a structure associated with olfactory memory and learning4,5. Here, we present electrophysiological recording techniques to monitor odor-evoked neural responses in these olfactory circuits. First, we present a single sensillum recording method to study odor-evoked responses at the level of populations of ORNs6,7. We discuss the use of saline filled sharpened glass pipettes as electrodes to extracellularly monitor ORN responses. Next, we present a method to extracellularly monitor PN responses using a commercial 16-channel electrode3. A similar approach using a custom-made 8-channel twisted wire tetrode is demonstrated for Kenyon cell recordings8. We provide details of our experimental setup and present representative recording traces for each of these techniques. PMID:23380828

  4. The Inositol 1,4,5-triphosphate kinase1 gene affects olfactory reception in Drosophila melanogaster.

    PubMed

    Gomez-Diaz, Carolina; Martin, Fernando; Alcorta, Esther

    2006-03-01

    The Inositol 1,4,5-triphosphate (IP3) route is one of the two main transduction cascades that mediate olfactory reception in Drosophila melanogaster. The activity of IP3 kinase1 reduces the levels of this substrate by phosphorylation into inositol 1,3,4,5-tetrakiphosphate (IP4). We show here that the gene is expressed in olfactory sensory organs as well as in the rest of the head. To evaluate in vivo the olfactory functional effects of up-regulating IP3K1, individuals with directed genetic changes at the reception level only were generated using the UAS/Gal4 method. In this report, we described the consequences in olfactory perception of overexpressing the IP3Kinase1 gene at eight different olfactory receptor-neuron subsets. Six out of the eight studied Gal-4/UAS-IP3K1 hybrids displayed abnormal behavioral responses to ethyl acetate, acetone, ethanol or propionaldehyde. Specific behavioral defects corresponded to the particular neuronal olfactory profile. These data confirm the role of the IP3kinase1 gene, and consequently the IP3 transduction cascade, in mediating olfactory information at the reception level.

  5. Parallel pathways convey olfactory information with opposite polarities in Drosophila.

    PubMed

    Wang, Kaiyu; Gong, Jiaxin; Wang, Qingxiu; Li, Hao; Cheng, Qi; Liu, Yafeng; Zeng, Shaoqun; Wang, Zuoren

    2014-02-25

    In insects, olfactory information received by peripheral olfactory receptor neurons (ORNs) is conveyed from the antennal lobes (ALs) to higher brain regions by olfactory projection neurons (PNs). Despite the knowledge that multiple types of PNs exist, little is known about how these different neuronal pathways work cooperatively. Here we studied the Drosophila GABAergic mediolateral antennocerebral tract PNs (mlPNs), which link ipsilateral AL and lateral horn (LH), in comparison with the cholinergic medial tract PNs (mPNs). We examined the connectivity of mlPNs in ALs and found that most mlPNs received inputs from both ORNs and mPNs and participated in AL network function by forming gap junctions with other AL neurons. Meanwhile, mlPNs might innervate LH neurons downstream of mPNs, exerting a feedforward inhibition. Using dual-color calcium imaging, which enables a simultaneous monitoring of neural activities in two groups of PNs, we found that mlPNs exhibited robust odor responses overlapping with, but broader than, those of mPNs. Moreover, preferentially down-regulation of GABA in most mlPNs caused abnormal courtship and aggressive behaviors in male flies. These findings demonstrate that in Drosophila, olfactory information in opposite polarities are carried coordinately by two parallel and interacted pathways, which could be essential for appropriate behaviors.

  6. Cell-based microfluidic platform for mimicking human olfactory system.

    PubMed

    Lee, Seung Hwan; Oh, Eun Hae; Park, Tai Hyun

    2015-12-15

    Various attempts have been made to mimic the human olfactory system using human olfactory receptors (hORs). In particular, OR-expressed cell-based odorant detection systems mimic the smell sensing mechanism of humans, as they exploit endogenous cellular signaling pathways. However, the majority of such cell-based studies have been performed in the liquid phase to maintain cell viability, and liquid odorants were used as detection targets. Here, we present a microfluidic device for the detection of gaseous odorants which more closely mimics the human olfactory system. Cells expressing hOR were cultured on a porous membrane. The membrane was then flipped over and placed between two compartments. The upper compartment is the gaseous part where gaseous odorants are supplied, while the lower compartment is the aqueous part where viable cells are maintained in the liquid medium. Using this simple microfluidic device, we were able to detect gaseous odorant molecules by a fluorescence signal. The fluorescence signal was generated by calcium influx resulting from the interaction between odorant molecules and the hOR. The system allowed detection of gaseous odorant molecules in real-time, and the findings showed that the fluorescence responses increased dose-dependently in the range of 0-2 ppm odorant. In addition, the system can discriminate among gaseous odorant molecules. This microfluidic system closely mimics the human olfactory system in the sense that the submerged cells detect gaseous odorants.

  7. Which solvent for olfactory testing?

    PubMed

    Philpott, C M; Goodenough, P C; Wolstenholme, C R; Murty, G E

    2004-12-01

    The physical properties of any carrier can deteriorate over time and thus alter the results in any olfactory test. The aim of this study was to evaluate clinically potential solvents as a clean odourless carrier for olfactory testing. Sweet almond oil, pure coconut oil, pure peach kernel oil, dipropylene glycol, monopropylene glycol, mineral oil and silicone oil were studied. The experimentation was conducted in two parts. First, an olfactory device was used to conduct air through the solvents on a weekly basis using a cohort of six volunteers to assess the perceived odour of each solvent at weekly intervals. Secondly a cross-reference test was performed using small bottled solutions of phenylethyl-alcohol and 1-butanol in 10-fold dilutions to compare any perceived difference in concentrations over a period of 8 weeks. We concluded that mineral oil is the most suitable carrier for the purpose of olfactory testing, possessing many desirable characteristics of an olfactory solvent, and that silicone oil may provide a suitable alternative for odorants with which it is miscible.

  8. Olfactory dysfunction in patients with multiple sclerosis.

    PubMed

    Li, Li-Min; Yang, Li-Na; Zhang, Lin-Jie; Fu, Ying; Li, Ting; Qi, Yuan; Wang, Jing; Zhang, Da-Qi; Zhang, Ningnannan; Liu, Jingchun; Yang, Li

    2016-06-15

    Association of changes in olfactory-related structures with olfactory function in patients with multiple sclerosis (MS) is not well understood. We used a T&T olfactometer test kit to evaluate olfactory function in 26 patients with MS and 26 age- and sex-matched healthy controls (HC). Then, Brain MRI were performed and olfactory-related structures were analyzed in these subjects. Olfactory detection and recognition threshold were significantly higher in the MS group, interestingly olfactory recognition threshold positively correlated with expanded disability status scale scores in these patients. Olfactory bulb (OB) volume reduced in patients with olfactory dysfunction (ODF). At the same time, reductions in gray matter (GM) volume were observed in the parahippocampal gyrus (PCG), amygdala, piriform cortex, and inferior frontal gyrus in patients with MS compared to HC. Atrophy of the PCG was more obvious in patients with ODF than patients without ODF and the PCG volume correlated with the olfactory recognition threshold, while no difference was found in fractional anisotropy values of tract-based spatial statistics analysis in the two groups. Olfactory function in patients with MS tends to become gradually more impaired with disability aggravation. Decreases in the volume of the OB and olfactory-related GM might provide valuable information about disease status in patients with MS with olfactory impairment. PMID:27206870

  9. Hebbian learning for olfactory sequences.

    PubMed

    Johnson, Andrew J; Cauchi, Laura; Miles, Christopher

    2013-06-01

    The present paper explores the generality of the Hebb repetition effect to the learning of olfactory sequences in order to assess commonality of memory functioning across sensory modalities. Participants completed a serial-order reconstruction task comprising sequences of four olfactory stimuli. Following presentation of each sequence, participants were re-presented with the odours and were required to reconstruct their order of presentation. Surreptitious re-presentation of the repeated sequence occurred on every third trial. This order reconstruction task produced a serial-position function comprising recency only for both the non-repeated and the repeated sequences. Importantly, serial-order reconstruction for the repeated odour sequence produced improved performance for that sequence compared to the non-repeated sequences. This observation of a Hebb repetition effect for olfactory sequences further supports the proposition that sequential learning can operate amodally.

  10. Olfactory dysfunction in Down's Syndrome.

    PubMed

    Murphy, C; Jinich, S

    1996-01-01

    Down's Syndrome subjects over 40 years old show neuropathology similar to that of Alzheimer's disease. The olfactory system is particularly vulnerable in Alzheimer's disease, both anatomically and functionally. Several measures of sensory and cognitive functioning were studied in the older Down's Syndrome patient, with the hypothesis of significant olfactory dysfunction. Participants were 23 Down's subjects, and 23 controls. The Dementia Rating Scale showed mean scores of 103 for Down's subjects and 141 for controls. Down's subjects showed significant deficits in odor detection threshold, odor identification, and odor recognition memory. Normal performance in a taste threshold task, similar to the olfactory threshold task in subject demands, suggested that the Down's syndrome subjects' poor performance was not due to task demands. Deficits in olfaction may provide a sensitive and early indicator of the deterioration and progression of the brain in older subjects with Down's Syndrome.

  11. Olfactory system oscillations across phyla.

    PubMed

    Kay, Leslie M

    2015-04-01

    Neural oscillations are ubiquitous in olfactory systems of mammals, insects and molluscs. Neurophysiological and computational investigations point to common mechanisms for gamma or odor associated oscillations across phyla (40-100Hz in mammals, 20-30Hz in insects, 0.5-1.5Hz in molluscs), engaging the reciprocal dendrodendritic synapse between excitatory principle neurons and inhibitory interneurons in the olfactory bulb (OB), antennal lobe (AL), or procerebrum (PrC). Recent studies suggest important mechanisms that may modulate gamma oscillations, including neuromodulators and centrifugal input to the OB and AL. Beta (20Hz) and theta (2-12Hz) oscillations coordinate activity within and across brain regions. Olfactory beta oscillations are associated with odor learning and depend on centrifugal OB input, while theta oscillations are strongly associated with respiration.

  12. Simple and sensitive detection of aflatoxin B1 within five minute using a non-conventional competitive immunosensing mode.

    PubMed

    Lin, Youxiu; Zhou, Qian; Lin, Yuping; Tang, Dianyong; Chen, Guonan; Tang, Dianping

    2015-12-15

    A novel competitive-type immunosensing strategy based on target-induced displacement reaction with antibody-functionalized mesoporous carbon (MSC) nanoparticles was designed for sensitive and rapid electrochemical detection of aflatoxin B1 (AFB1, used as a model) on the Nafion-functionalized sensing interface. Electroactive thionine molecules were initially decorated to the mesoporous carbon, and polyclonal anti-AFB1 antibody was then covalently conjugated to the nanostructures. The immunosensor was simply prepared via the electrostatic interaction between negatively charged Nafion film and positively charged anti-AFB1 antibody accompanying the nanostructures. The electrochemical signal originated from the carried thionine to mesoporous carbon. Upon target AFB1 introduction, the analyte reacted with the labeled anti-AFB1 antibody on the MSC based on specific antigen-antibody reaction and induced the dissociation of thionine-MSN nanostructures from the sensing interface, thus decreasing the cathodic current of the carried thionine molecules. Under optimal conditions, the immunosensor exhibited good electrochemical responses for determination of target AFB1 at a concentration as low as 3.0 pg mL(-1) (3.0 ppt). Importantly, the non-conventional sensing system provides a promising immunosensing strategy for rapid screening of small molecules because of its simplicity, low cost and sensitivity without the needs of sample separation and washing step.

  13. Defatted algal biomass as a non-conventional low-cost adsorbent: surface characterization and methylene blue adsorption characteristics.

    PubMed

    Sarat Chandra, T; Mudliar, S N; Vidyashankar, S; Mukherji, S; Sarada, R; Krishnamurthi, K; Chauhan, V S

    2015-05-01

    The present study investigates the use of defatted algal biomass (DAB) as a non-conventional low cost adsorbent. The maximum adsorption capacity of biomass (raw, defatted and sulfuric acid pretreated DAB) was determined by liquid phase adsorption studies in batch mode for the removal of methylene blue present at various concentrations (1, 2, 3, 4, and 5 mg L(-1)) from aqueous solutions. The data was well fitted with Langmuir and Freundlich isotherms. The maximum adsorption capacity for raw, defatted and sulfuric acid pretreated DAB was found to be 6.0, 7.73 and 7.80 mg g(-1), respectively. The specific surface area of raw, defatted and sulfuric acid pretreated DAB was estimated to be 14.70, 18.94, and 19.10 m(2) g(-1), respectively. To evaluate the kinetic mechanism that controls the adsorption process, pseudo-first order, pseudo-second order, intraparticle diffusion and particle diffusion has been tested. The data fitted quite well with pseudo-second order kinetic model.

  14. Looking beyond Saccharomyces: the potential of non-conventional yeast species for desirable traits in bioethanol fermentation.

    PubMed

    Radecka, Dorota; Mukherjee, Vaskar; Mateo, Raquel Quintilla; Stojiljkovic, Marija; Foulquié-Moreno, María R; Thevelein, Johan M

    2015-09-01

    Saccharomyces cerevisiae has been used for millennia in the production of food and beverages and is by far the most studied yeast species. Currently, it is also the most used microorganism in the production of first-generation bioethanol from sugar or starch crops. Second-generation bioethanol, on the other hand, is produced from lignocellulosic feedstocks that are pretreated and hydrolyzed to obtain monomeric sugars, mainly D-glucose, D-xylose and L-arabinose. Recently, S. cerevisiae recombinant strains capable of fermenting pentose sugars have been generated. However, the pretreatment of the biomass results in hydrolysates with high osmolarity and high concentrations of inhibitors. These compounds negatively influence the fermentation process. Therefore, robust strains with high stress tolerance are required. Up to now, more than 2000 yeast species have been described and some of these could provide a solution to these limitations because of their high tolerance to the most predominant stress conditions present in a second-generation bioethanol reactor. In this review, we will summarize what is known about the non-conventional yeast species showing unusual tolerance to these stresses, namely Zygosaccharomyces rouxii (osmotolerance), Kluyveromyces marxianus and Ogataea (Hansenula) polymorpha (thermotolerance), Dekkera bruxellensis (ethanol tolerance), Pichia kudriavzevii (furan derivatives tolerance) and Z. bailii (acetic acid tolerance). PMID:26126524

  15. Optimization of the magnetic horn for the nuSTORM non-conventional neutrino beam using the genetic algorithm

    DOE PAGES

    Liu, A.; Bross, A.; Neuffer, D.

    2015-05-28

    This paper describes the strategy for optimizing the magnetic horn for the neutrinos from STORed Muons (nuSTORM) facility. The nuSTORM magnetic horn is the primary collection device for the secondary particles generated by bombarding a solid target with 120 GeV protons. As a consequence of the non-conventional beamline designed for nuSTORM, the requirements on the horn are different from those for a conventional neutrino beamline. At nuSTORM, muons decay while circulating in the storage ring, and the detectors are placed downstream of the production straight so as to be exposed to the neutrinos from muon decay. nuSTORM aims at preciselymore » measuring the neutrino cross sections, and providing a definitive statement about the existence of sterile neutrinos. The nuSTORM horn aims at focusing the pions into a certain phase space so that more muons from pion decay can be accepted by the decay ring. The paper demonstrates a numerical method that was developed to optimize the horn design to gain higher neutrino flux from the circulating muons. A Genetic Algorithm (GA) was applied to the simultaneous optimization of the two objectives in this study. In conclusion, the application of the technique discussed in this paper is not limited to either the nuSTORM facility or muon based facilities, but can be used for other neutrino facilities that use magnetic horns as collection devices.« less

  16. Optimization of the magnetic horn for the nuSTORM non-conventional neutrino beam using the genetic algorithm

    SciTech Connect

    Liu, A.; Bross, A.; Neuffer, D.

    2015-05-28

    This paper describes the strategy for optimizing the magnetic horn for the neutrinos from STORed Muons (nuSTORM) facility. The nuSTORM magnetic horn is the primary collection device for the secondary particles generated by bombarding a solid target with 120 GeV protons. As a consequence of the non-conventional beamline designed for nuSTORM, the requirements on the horn are different from those for a conventional neutrino beamline. At nuSTORM, muons decay while circulating in the storage ring, and the detectors are placed downstream of the production straight so as to be exposed to the neutrinos from muon decay. nuSTORM aims at precisely measuring the neutrino cross sections, and providing a definitive statement about the existence of sterile neutrinos. The nuSTORM horn aims at focusing the pions into a certain phase space so that more muons from pion decay can be accepted by the decay ring. The paper demonstrates a numerical method that was developed to optimize the horn design to gain higher neutrino flux from the circulating muons. A Genetic Algorithm (GA) was applied to the simultaneous optimization of the two objectives in this study. In conclusion, the application of the technique discussed in this paper is not limited to either the nuSTORM facility or muon based facilities, but can be used for other neutrino facilities that use magnetic horns as collection devices.

  17. Looking beyond Saccharomyces: the potential of non-conventional yeast species for desirable traits in bioethanol fermentation.

    PubMed

    Radecka, Dorota; Mukherjee, Vaskar; Mateo, Raquel Quintilla; Stojiljkovic, Marija; Foulquié-Moreno, María R; Thevelein, Johan M

    2015-09-01

    Saccharomyces cerevisiae has been used for millennia in the production of food and beverages and is by far the most studied yeast species. Currently, it is also the most used microorganism in the production of first-generation bioethanol from sugar or starch crops. Second-generation bioethanol, on the other hand, is produced from lignocellulosic feedstocks that are pretreated and hydrolyzed to obtain monomeric sugars, mainly D-glucose, D-xylose and L-arabinose. Recently, S. cerevisiae recombinant strains capable of fermenting pentose sugars have been generated. However, the pretreatment of the biomass results in hydrolysates with high osmolarity and high concentrations of inhibitors. These compounds negatively influence the fermentation process. Therefore, robust strains with high stress tolerance are required. Up to now, more than 2000 yeast species have been described and some of these could provide a solution to these limitations because of their high tolerance to the most predominant stress conditions present in a second-generation bioethanol reactor. In this review, we will summarize what is known about the non-conventional yeast species showing unusual tolerance to these stresses, namely Zygosaccharomyces rouxii (osmotolerance), Kluyveromyces marxianus and Ogataea (Hansenula) polymorpha (thermotolerance), Dekkera bruxellensis (ethanol tolerance), Pichia kudriavzevii (furan derivatives tolerance) and Z. bailii (acetic acid tolerance).

  18. Immunocytochemical characterisation of ensheathing glia in the olfactory and vomeronasal systems of Ambystoma mexicanum (Caudata: Ambystomatidae).

    PubMed

    Lazzari, Maurizio; Bettini, Simone; Franceschini, Valeria

    2016-03-01

    The olfactory and vomeronasal systems of vertebrates are characterised by neurogenesis occurring throughout life. The regenerative ability of olfactory receptor neurons relies on specific glial cells, the olfactory and vomeronasal axon-surrounding cells. Numerous studies have examined mammalian olfactory ensheathing cells which are considered potential candidates for spinal cord injury repair using cell-based therapy. With regard to non-mammalian vertebrates, limited information is available on these glial cells in fish, and there is no information on them in terrestrial anamniotes, the amphibians. In the present research, we studied the immunocytochemical characteristics of axon-surrounding cells in Ambystoma mexicanum. Urodeles have relatively simple olfactory and vomeronasal systems, and represent a good model for studying ensheathing cells in extant representatives of basal tetrapods. Sections from the decalcified heads of A. mexicanum were immunocytochemically processed for the detection of proteins used in research on mammalian olfactory-ensheathing cells. S100, GFAP and NCAM were clearly observed. p75NTR, Gal-1 and PSA-NCAM showed weak staining. No vimentin immunopositivity was observed. The corresponding areas of the olfactory and vomeronasal pathways displayed the same staining characteristics, with the exception of Gal-1, p75NTR and PSA-NCAM in the mucosae. The degree of marker expression was not uniform throughout the sensory pathways. In contrast to fish, both olfactory and vomeronasal nerves displayed uniform staining intensity. This study showed that some markers for mammalian and fish-ensheathing glia are also applicable in urodeles. The olfactory systems of vertebrates show similarities, and also clear dissimilarities. Further investigations are required to ascertain the functional significance of these regional and interspecific differences.

  19. Immunocytochemical characterisation of ensheathing glia in the olfactory and vomeronasal systems of Ambystoma mexicanum (Caudata: Ambystomatidae).

    PubMed

    Lazzari, Maurizio; Bettini, Simone; Franceschini, Valeria

    2016-03-01

    The olfactory and vomeronasal systems of vertebrates are characterised by neurogenesis occurring throughout life. The regenerative ability of olfactory receptor neurons relies on specific glial cells, the olfactory and vomeronasal axon-surrounding cells. Numerous studies have examined mammalian olfactory ensheathing cells which are considered potential candidates for spinal cord injury repair using cell-based therapy. With regard to non-mammalian vertebrates, limited information is available on these glial cells in fish, and there is no information on them in terrestrial anamniotes, the amphibians. In the present research, we studied the immunocytochemical characteristics of axon-surrounding cells in Ambystoma mexicanum. Urodeles have relatively simple olfactory and vomeronasal systems, and represent a good model for studying ensheathing cells in extant representatives of basal tetrapods. Sections from the decalcified heads of A. mexicanum were immunocytochemically processed for the detection of proteins used in research on mammalian olfactory-ensheathing cells. S100, GFAP and NCAM were clearly observed. p75NTR, Gal-1 and PSA-NCAM showed weak staining. No vimentin immunopositivity was observed. The corresponding areas of the olfactory and vomeronasal pathways displayed the same staining characteristics, with the exception of Gal-1, p75NTR and PSA-NCAM in the mucosae. The degree of marker expression was not uniform throughout the sensory pathways. In contrast to fish, both olfactory and vomeronasal nerves displayed uniform staining intensity. This study showed that some markers for mammalian and fish-ensheathing glia are also applicable in urodeles. The olfactory systems of vertebrates show similarities, and also clear dissimilarities. Further investigations are required to ascertain the functional significance of these regional and interspecific differences. PMID:25433448

  20. Gene Expression Profiles of Main Olfactory Epithelium in Adenylyl Cyclase 3 Knockout Mice

    PubMed Central

    Wang, Zhenshan; Zhou, Yanfen; Luo, Yingtao; Zhang, Jing; Zhai, Yunpeng; Yang, Dong; Zhang, Zhe; Li, Yongchao; Storm, Daniel R.; Ma, Runlin Z.

    2015-01-01

    Adenylyl Cyclase 3 (AC3) plays an important role in the olfactory sensation-signaling pathway in mice. AC3 deficiency leads to defects in olfaction. However, it is still unknown whether AC3 deficiency affects gene expression or olfactory signal transduction pathways within the main olfactory epithelium (MOE). In this study, gene microarrays were used to screen differentially expressed genes in MOE from AC3 knockout (AC3−/−) and wild-type (AC3+/+) mice. The differentially expressed genes identified were subjected to bioinformatic analysis and verified by qRT-PCR. Gene expression in the MOE from AC3−/− mice was significantly altered, compared to AC3+/+ mice. Of the 41266 gene probes, 3379 had greater than 2-fold fold change in expression levels between AC3−/− and AC3+/+ mice, accounting for 8% of the total gene probes. Of these genes, 1391 were up regulated, and 1988 were down regulated, including 425 olfactory receptor genes, 99 genes that are specifically expressed in the immature olfactory neurons, 305 genes that are specifically expressed in the mature olfactory neurons, and 155 genes that are involved in epigenetic regulation. Quantitative RT-PCR verification of the differentially expressed epigenetic regulation related genes, olfactory receptors, ion transporter related genes, neuron development and differentiation related genes, lipid metabolism and membrane protein transport etc. related genes showed that P75NTR, Hinfp, Gadd45b, and Tet3 were significantly up-regulated, while Olfr370, Olfr1414, Olfr1208, Golf, Faim2, Tsg101, Mapk10, Actl6b, H2BE, ATF5, Kirrrel2, OMP, Drd2 etc. were significantly down-regulated. In summary, AC3 may play a role in proximal olfactory signaling and play a role in the regulation of differentially expressed genes in mouse MOE. PMID:26633363

  1. Gene Expression Profiles of Main Olfactory Epithelium in Adenylyl Cyclase 3 Knockout Mice.

    PubMed

    Wang, Zhenshan; Zhou, Yanfen; Luo, Yingtao; Zhang, Jing; Zhai, Yunpeng; Yang, Dong; Zhang, Zhe; Li, Yongchao; Storm, Daniel R; Ma, Runlin Z

    2015-11-30

    Adenylyl Cyclase 3 (AC3) plays an important role in the olfactory sensation-signaling pathway in mice. AC3 deficiency leads to defects in olfaction. However, it is still unknown whether AC3 deficiency affects gene expression or olfactory signal transduction pathways within the main olfactory epithelium (MOE). In this study, gene microarrays were used to screen differentially expressed genes in MOE from AC3 knockout (AC3(-/-)) and wild-type (AC3(+/+)) mice. The differentially expressed genes identified were subjected to bioinformatic analysis and verified by qRT-PCR. Gene expression in the MOE from AC3(-/-) mice was significantly altered, compared to AC3(+/+) mice. Of the 41266 gene probes, 3379 had greater than 2-fold fold change in expression levels between AC3(-/-) and AC3(+/+) mice, accounting for 8% of the total gene probes. Of these genes, 1391 were up regulated, and 1988 were down regulated, including 425 olfactory receptor genes, 99 genes that are specifically expressed in the immature olfactory neurons, 305 genes that are specifically expressed in the mature olfactory neurons, and 155 genes that are involved in epigenetic regulation. Quantitative RT-PCR verification of the differentially expressed epigenetic regulation related genes, olfactory receptors, ion transporter related genes, neuron development and differentiation related genes, lipid metabolism and membrane protein transport etc. related genes showed that P75NTR, Hinfp, Gadd45b, and Tet3 were significantly up-regulated, while Olfr370, Olfr1414, Olfr1208, Golf, Faim2, Tsg101, Mapk10, Actl6b, H2BE, ATF5, Kirrrel2, OMP, Drd2 etc. were significantly down-regulated. In summary, AC3 may play a role in proximal olfactory signaling and play a role in the regulation of differentially expressed genes in mouse MOE.

  2. Early survival factor deprivation in the olfactory epithelium enhances activity-driven survival

    PubMed Central

    François, Adrien; Laziz, Iman; Rimbaud, Stéphanie; Grebert, Denise; Durieux, Didier; Pajot-Augy, Edith; Meunier, Nicolas

    2013-01-01

    The neuronal olfactory epithelium undergoes permanent renewal because of environmental aggression. This renewal is partly regulated by factors modulating the level of neuronal apoptosis. Among them, we had previously characterized endothelin as neuroprotective. In this study, we explored the effect of cell survival factor deprivation in the olfactory epithelium by intranasal delivery of endothelin receptors antagonists to rat pups. This treatment induced an overall increase of apoptosis in the olfactory epithelium. The responses to odorants recorded by electroolfactogram were decreased in treated animal, a result consistent with a loss of olfactory sensory neurons (OSNs). However, the treated animal performed better in an olfactory orientation test based on maternal odor compared to non-treated littermates. This improved performance could be due to activity-dependent neuronal survival of OSNs in the context of increased apoptosis level. In order to demonstrate it, we odorized pups with octanal, a known ligand for the rI7 olfactory receptor (Olr226). We quantified the number of OSN expressing rI7 by RT-qPCR and whole mount in situ hybridization. While this number was reduced by the survival factor removal treatment, this reduction was abolished by the presence of its ligand. This improved survival was optimal for low concentration of odorant and was specific for rI7-expressing OSNs. Meanwhile, the number of rI7-expressing OSNs was not affected by the odorization in non-treated littermates; showing that the activity-dependant survival of OSNs did not affect the OSN population during the 10 days of odorization in control conditions. Overall, our study shows that when apoptosis is promoted in the olfactory mucosa, the activity-dependent neuronal plasticity allows faster tuning of the olfactory sensory neuron population toward detection of environmental odorants. PMID:24399931

  3. Subchronic inhalation exposure to 2-ethyl-1-hexanol impairs the mouse olfactory bulb via injury and subsequent repair of the nasal olfactory epithelium.

    PubMed

    Miyake, Mio; Ito, Yuki; Sawada, Masato; Sakai, Kiyoshi; Suzuki, Himiko; Sakamoto, Tatsuo; Sawamoto, Kazunobu; Kamijima, Michihiro

    2016-08-01

    The olfactory system can be a toxicological target of volatile organic compounds present in indoor air. Recently, 2-ethyl-1-hexanol (2E1H) emitted from adhesives and carpeting materials has been postulated to cause "sick building syndrome." Patients' symptoms are associated with an increased sense of smell. This investigation aimed to characterize the histopathological changes of the olfactory epithelium (OE) of the nasal cavity and the olfactory bulb (OB) in the brain, due to subchronic exposure to 2E1H. Male ICR mice were exposed to 0, 20, 60, or 150 ppm 2E1H for 8 h every day for 1 week, or 5 days per week for 1 or 3 months. After a 1-week exposure, the OE showed inflammation and degeneration, with a significant concentration-dependent reduction in the staining of olfactory receptor neurons and in the numbers of globose basal cells at ≥20 ppm. Regeneration occurred at 1 month along with an increase in the basal cells, but lymphocytic infiltration, expanded Bowman's glands, and a decrease in the olfactory receptor neurons were observed at 3 months. Intriguingly, the OB at 3 months showed a reduction in the diameters of the glomeruli and in the number of olfactory nerves and tyrosine hydroxylase-positive neurons, but an increased number of ionized calcium-binding adaptor molecule 1-positive microglia in glomeruli. Accordingly, 2E1H inhalation induced degeneration of the OE with the lowest-observed-adverse-effect level of 20 ppm. The altered number of functional cell components in the OB suggests that effects on olfactory sensation persist after subchronic exposure to 2E1H. PMID:27055686

  4. Olfactory dysfunction in Alzheimer’s disease

    PubMed Central

    Zou, Yong-ming; Lu, Da; Liu, Li-ping; Zhang, Hui-hong; Zhou, Yu-ying

    2016-01-01

    Alzheimer’s disease (AD) is a common neurodegenerative disorder with the earliest clinical symptom of olfactory dysfunction, which is a potential clinical marker for AD severity and progression. However, many questions remain unanswered. This article reviews relevant research on olfactory dysfunction in AD and evaluates the predictive value of olfactory dysfunction for the epidemiological, pathophysiological, and clinical features of AD, as well as for the conversion of cognitive impairment to AD. We summarize problems of existing studies and provide a useful reference for further studies in AD olfactory dysfunction and for clinical applications of olfactory testing. PMID:27143888

  5. Olfactory subsystems in the honeybee: sensory supply and sex specificity.

    PubMed

    Kropf, Jan; Kelber, Christina; Bieringer, Kathrin; Rössler, Wolfgang

    2014-09-01

    The antennae of honeybee (Apis mellifera) workers and drones differ in various aspects. One striking difference is the presence of Sensilla basiconica in (female) workers and their absence in (male) drones. We investigate the axonal projection patterns of olfactory receptor neurons (ORNs) housed in S. basiconica in honeybee workers by using selective anterograde labeling with fluorescent tracers and confocal-microscopy analysis of axonal projections in antennal lobe glomeruli. Axons of S. basiconica-associated ORNs preferentially projected into a specific glomerular cluster in the antennal lobe, namely the sensory input-tract three (T3) cluster. T3-associated glomeruli had previously been shown to be innervated by uniglomerular projection (output) neurons of the medial antennal lobe tract (mALT). As the number of T3 glomeruli is reduced in drones, we wished to determine whether this was associated with the reduction of glomeruli innervated by medial-tract projection neurons. We retrogradely traced mALT projection neurons in drones and counted the innervated glomeruli. The number of mALT-associated glomeruli was strongly reduced in drones compared with workers. The preferential projections of S. basiconica-associated ORNs in T3 glomeruli together with the reduction of mALT-associated glomeruli support the presence of a female (worker)-specific olfactory subsystem that is partly innervated by ORNs from S. basiconica and is associated with the T3 cluster of glomeruli and mALT projection neurons. We propose that this olfactory subsystem supports parallel olfactory processing related to worker-specific olfactory tasks such as the coding of colony odors, colony pheromones and/or odorants associated with foraging on floral resources.

  6. Olfactory subsystems in the honeybee: sensory supply and sex specificity.

    PubMed

    Kropf, Jan; Kelber, Christina; Bieringer, Kathrin; Rössler, Wolfgang

    2014-09-01

    The antennae of honeybee (Apis mellifera) workers and drones differ in various aspects. One striking difference is the presence of Sensilla basiconica in (female) workers and their absence in (male) drones. We investigate the axonal projection patterns of olfactory receptor neurons (ORNs) housed in S. basiconica in honeybee workers by using selective anterograde labeling with fluorescent tracers and confocal-microscopy analysis of axonal projections in antennal lobe glomeruli. Axons of S. basiconica-associated ORNs preferentially projected into a specific glomerular cluster in the antennal lobe, namely the sensory input-tract three (T3) cluster. T3-associated glomeruli had previously been shown to be innervated by uniglomerular projection (output) neurons of the medial antennal lobe tract (mALT). As the number of T3 glomeruli is reduced in drones, we wished to determine whether this was associated with the reduction of glomeruli innervated by medial-tract projection neurons. We retrogradely traced mALT projection neurons in drones and counted the innervated glomeruli. The number of mALT-associated glomeruli was strongly reduced in drones compared with workers. The preferential projections of S. basiconica-associated ORNs in T3 glomeruli together with the reduction of mALT-associated glomeruli support the presence of a female (worker)-specific olfactory subsystem that is partly innervated by ORNs from S. basiconica and is associated with the T3 cluster of glomeruli and mALT projection neurons. We propose that this olfactory subsystem supports parallel olfactory processing related to worker-specific olfactory tasks such as the coding of colony odors, colony pheromones and/or odorants associated with foraging on floral resources. PMID:24817103

  7. Olfactory Ensheathing Cells Express α7 Integrin to Mediate Their Migration on Laminin

    PubMed Central

    Ingram, Norianne T.; Khankan, Rana R.; Phelps, Patricia E.

    2016-01-01

    The unique glia located in the olfactory system, called olfactory ensheathing cells (OECs), are implicated as an attractive choice for transplantation therapy following spinal cord injury because of their pro-regenerative characteristics. Adult OECs are thought to improve functional recovery and regeneration after injury by secreting neurotrophic factors and making cell-to-cell contacts with regenerating processes, but the mechanisms are not well understood. We show first that α7 integrin, a laminin receptor, is highly expressed at the protein level by OECs throughout the olfactory system, i.e., in the olfactory mucosa, olfactory nerve, and olfactory nerve layer of the olfactory bulb. Then we asked if OECs use the α7 integrin receptor directly to promote neurite outgrowth on permissive and neutral substrates, in vitro. We co-cultured α7+/+ and α7lacZ/lacZ postnatal cerebral cortical neurons with α7+/+ or α7lacZ/lacZ OECs and found that genotype did not effect the ability of OECs to enhance neurite outgrowth by direct contact. Loss of α7 integrin did however significantly decrease the motility of adult OECs in transwell experiments. Twice as many α7+/+ OECs migrated through laminin-coated transwells compared to α7+/+ OECs on poly-L-lysine (PLL). This is in contrast to α7lacZ/lacZ OECs, which showed no migratory preference for laminin substrate over PLL. These results demonstrate that OECs express α7 integrin, and that laminin and its α7 integrin receptor contribute to adult OEC migration in vitro and perhaps also in vivo. PMID:27078717

  8. Formation of complexes between hematite nanoparticles and a non-conventional galactomannan gum. Toward a better understanding on interaction processes.

    PubMed

    Busch, Verónica M; Loosli, Fréderic; Santagapita, Patricio R; Buera, M Pilar; Stoll, Serge

    2015-11-01

    The physicochemical characteristics of hematite nanoparticles related to their size, surface area and reactivity make them useful for many applications, as well as suitable models to study aggregation kinetics. For several applications (such as remediation of contaminated groundwater) it is crucial to maintain the stability of hematite nanoparticle suspensions in order to assure their arrival to the target place. The use of biopolymers has been proposed as a suitable environmentally friendly option to avoid nanoparticle aggregation and assure their stability. The aim of the present work was to investigate the formation of complexes between hematite nanoparticles and a non-conventional galactomannan (vinal gum--VG) obtained from Prosopis ruscifolia in order to promote hematite nanoparticle coating with a green biopolymer. Zeta potential and size of hematite nanoparticles, VG dispersions and the stability of their mixtures were investigated, as well as the influence of the biopolymer concentration and preparation method. DLS and nanoparticle tracking analysis techniques were used for determining the size and the zeta-potential of the suspensions. VG showed a polydispersed size distribution (300-475 nm Z-average diameter, 0.65 Pdi) and a negative zeta potential (between -1 and -12 mV for pH2 and 12, respectively). The aggregation of hematite nanoparticles (3.3 mg/L) was induced by the addition of VG at lower concentrations than 2mg/L (pH5.5). On the other hand, hematite nanoparticles were stabilized at concentrations of VG higher than 2 mg/L. Several phenomena between hematite nanoparticles and VG were involved: steric effects, electrostatic interactions, charge neutralization, charge inversion and polymer bridging. The process of complexation between hematite nanoparticles and the biopolymer was strongly influenced by the preparation protocols. It was concluded that the aggregation, dispersion, and stability of hematite nanoparticles depended on biopolymer

  9. Hypothyroidism Affects Olfactory Evoked Potentials

    PubMed Central

    Świdziński, Teodor; Czerniejewska-Wolska, Hanna; Wiskirska-Woźnica, Bożena; Owecki, Maciej; Głowacka, Maria Danuta; Frankowska, Anna; Łącka, Katarzyna; Glapiński, Mariusz; Maciejewska-Szaniec, Zofia; Świdziński, Piotr

    2016-01-01

    Background. Objective electrophysiological methods for investigations of the organ of smell consist in recordings of olfactory cortex responses to specific, time restricted odor stimuli. In hypothyroidism have impaired sense of smell. Material and Methods. Two groups: control of 31 healthy subjects and study group of 21 with hypothyroidism. The inclusion criterion for the study group was the TSH range from 3.54 to 110 μIU/mL. Aim. Assessment of the latency time of evoked responses from the olfactory nerve N1 and the trigeminal nerve N5 using two smells of mint and anise in hypothyroidism. Results. The smell perception in subjective olfactory tests was normal in 85% of the hypothyroid group. Differences were noticed in the objective tests. The detailed intergroup analysis of latency times of recorded cortical responses PN5 and PN1 performed by means between the groups of patients with overt clinical hypothyroidism versus subclinical hypothyroidism demonstrated a significant difference (p < 0.05) whereas no such differences were found between the control group versus subclinical hypothyroidism group (p > 0.05). Conclusion. We can conclude that registration of cortex potentials at irritation of olfactory and trigeminal nerves offers possibilities for using this method as an objective indicator of hypothyroidism severity and prognostic process factor. PMID:27656655

  10. Hypothyroidism Affects Olfactory Evoked Potentials

    PubMed Central

    Świdziński, Teodor; Czerniejewska-Wolska, Hanna; Wiskirska-Woźnica, Bożena; Owecki, Maciej; Głowacka, Maria Danuta; Frankowska, Anna; Łącka, Katarzyna; Glapiński, Mariusz; Maciejewska-Szaniec, Zofia; Świdziński, Piotr

    2016-01-01

    Background. Objective electrophysiological methods for investigations of the organ of smell consist in recordings of olfactory cortex responses to specific, time restricted odor stimuli. In hypothyroidism have impaired sense of smell. Material and Methods. Two groups: control of 31 healthy subjects and study group of 21 with hypothyroidism. The inclusion criterion for the study group was the TSH range from 3.54 to 110 μIU/mL. Aim. Assessment of the latency time of evoked responses from the olfactory nerve N1 and the trigeminal nerve N5 using two smells of mint and anise in hypothyroidism. Results. The smell perception in subjective olfactory tests was normal in 85% of the hypothyroid group. Differences were noticed in the objective tests. The detailed intergroup analysis of latency times of recorded cortical responses PN5 and PN1 performed by means between the groups of patients with overt clinical hypothyroidism versus subclinical hypothyroidism demonstrated a significant difference (p < 0.05) whereas no such differences were found between the control group versus subclinical hypothyroidism group (p > 0.05). Conclusion. We can conclude that registration of cortex potentials at irritation of olfactory and trigeminal nerves offers possibilities for using this method as an objective indicator of hypothyroidism severity and prognostic process factor.

  11. Olfactory dysfunction in degenerative ataxias.

    PubMed

    Connelly, T; Farmer, J M; Lynch, D R; Doty, R L

    2003-10-01

    Several lines of evidence suggest that the cerebellum may play a role in higher-order olfactory processing. In this study, we administered the University of Pennsylvania Smell Identification Test (UPSIT), a standardised test of olfactory function, to patients with ataxias primarily due to cerebellar pathology (spinocerebellar ataxias and related disorders) and to patients with Friedreich ataxia, an ataxia associated mainly with loss of afferent cerebellar pathways. UPSIT scores were slightly lower in both patient groups than in the control subjects, but no differences were noted between the scores of the Friedreich and the other ataxia patients. Within the Friedreich ataxia group, the smell test scores did not correlate with the number of pathologic GAA repeats (a marker of genetic severity), disease duration, or categorical ambulatory ability. UPSIT scores did not correlate with disease duration, although they correlated marginally with ambulatory status in the patients with cerebellar pathology. This study suggests that olfactory dysfunction may be a subtle clinical component of degenerative ataxias, in concordance with the hypothesis that the cerebellum or its afferents plays some role in central olfactory processing.

  12. Segregated pathways to the vomeronasal amygdala: differential projections from the anterior and posterior divisions of the accessory olfactory bulb.

    PubMed

    Mohedano-Moriano, Alicia; Pro-Sistiaga, Palma; Ubeda-Bañón, Isabel; Crespo, Carlos; Insausti, Ricardo; Martinez-Marcos, Alino

    2007-04-01

    Apically and basally located receptor neurons in the vomeronasal sensory epithelium express G(i2 alpha)- and G(o alpha)-proteins, V1R and V2R vomeronasal receptors, project to the anterior and posterior accessory olfactory bulb and respond to different stimuli, respectively. The extent to which secondary projections from the two portions of the accessory olfactory bulb are convergent in the vomeronasal amygdala is controversial. This issue is addressed by using anterograde and retrograde tract-tracing methods in rats including electron microscopy. Injections of dextran-amines, Fluoro Gold, cholera toxin-B subunit and Fast Blue were delivered to the anterior and posterior accessory olfactory bulb, bed nucleus of the stria terminalis, dorsal anterior amygdala and bed nucleus of the accessory olfactory tract/anteroventral medial amygdaloid nucleus. We have demonstrated that, apart from common vomeronasal-recipient areas, only the anterior accessory olfactory bulb projects to the bed nucleus of the stria terminalis, medial division, posteromedial part, and only the posterior accessory olfactory bulb projects to the dorsal anterior amygdala and deep cell layers of the bed nucleus of the accessory olfactory tract and the anteroventral medial amygdaloid nucleus. These results provide evidence that, excluding areas of convergence, the V1R and V2R vomeronasal pathways project to specific areas of the amygdala. These two vomeronasal subsystems are therefore anatomically and functionally separated in the telencephalon.

  13. Experience-dependent modification of primary sensory synapses in the mammalian olfactory bulb.

    PubMed

    Tyler, William J; Petzold, Gabor C; Pal, Sumon K; Murthy, Venkatesh N

    2007-08-29

    Experience-dependent changes in neural circuits have traditionally been investigated several synapses downstream of sensory input. Whether experience can alter the strength of primary sensory synapses remains mostly unknown. To address this issue, we investigated the consequences of odor deprivation on synapses made by olfactory sensory axons in the olfactory bulb of rats. Odor deprivation triggered an increase in the probability of glutamate release from olfactory sensory neuron synapses. Deprivation also increased the amplitude of quantal synaptic currents mediated by AMPA- and NMDA-type glutamate receptors, as well as the abundance of these receptors in the glomerular region. Our results demonstrate that sensory experience is capable of modulating synaptic strength at the earliest stages of information transfer between the environment and an organism. Such compensatory experience-dependent changes may represent a mechanism of sensory gain control.

  14. Finding Multiple Internal Rates of Return for a Project with Non-Conventional Cash Flows: Utilizing Popular Financial/Graphing Calculators and Spreadsheet Software

    ERIC Educational Resources Information Center

    Chen, Jeng-Hong

    2008-01-01

    This study demonstrates that a popular graphing calculator among students, TI-83 Plus, has a powerful function to draw the NPV profile and find the accurate multiple IRRs for a project with non-conventional cash flows. However, finance textbooks or related supplementary materials do not provide students instructions for this part. The detailed…

  15. Centrifugal innervation of the mammalian olfactory bulb.

    PubMed

    Matsutani, Shinji; Yamamoto, Noboru

    2008-12-01

    Although it has been known for decades that the mammalian olfactory bulb receives a substantial number of centrifugal inputs from other regions of the brain, relatively few data have been available on the function of the centrifugal olfactory system. Knowing the role of the centrifugal projection and how it works is of critical importance to fully understanding olfaction. The centrifugal fibers can be classified into two groups, a group that release neuromodulators, such as noradrenaline, serotonin, or acetylcholine, and a group originating in the olfactory cortex. Accumulating evidence suggests that centrifugal neuromodulatory inputs are associated with acquisition of odor memory. Because the distribution of the terminals on these fibers is diffuse and widespread, the neuromodulatory inputs must affect diverse subsets of bulbar neurons at the same time. In contrast, knowledge of the role of centrifugal fibers from the olfactory cortical areas is limited. Judging from recent morphological evidence, these fibers may modify the activity of neurons located in sparse and discrete loci in the olfactory bulb. Given the modular organization of the olfactory bulb, centrifugal fibers from the olfactory cortex may help coordinate the activities of restricted subsets of neurons belonging to distinct functional modules in an odor-specific manner. Because the olfactory cortex receives inputs from limbic and neocortical areas in addition to inputs from the bulb, the centrifugal inputs from the cortex can modulate odor processing in the bulb in response to non-olfactory as well as olfactory cues.

  16. Histological and lectin histochemical studies on the olfactory and respiratory mucosae of the sheep.

    PubMed

    Ibrahim, Dalia; Nakamuta, Nobuaki; Taniguchi, Kazumi; Yamamoto, Yoshio; Taniguchi, Kazuyuki

    2014-03-01

    The olfactory and respiratory mucosae of the Corriedale sheep were examined using lectin histochemistry in order to clarify the histochemical and glycohistochemical differences between these two tissues. The olfactory epithelium was stained with 13 lectins out of 21 lectins examined, while the respiratory epithelium was positive to 16 lectins. The free border of both of the olfactory and respiratory epithelia was stained with 12 lectins: Wheat germ agglutinin (WGA), succinylated-wheat germ agglutinin (s-WGA), Lycopersicon esculentum lectin (LEL), Solanum tuberosum lectin (STL), Datura stramonium lectin (DSL), Soybean agglutinin (SBA), Bandeiraea simplicifolia lectin-I (BSL-I), Ricinus communis agglutinin-I (RCA-120), Erythrina cristagalli lectin (ECL), Concanavalin A (Con A), Phaseolus vulgaris agglutinin-E (PHA-E) and Phaseolus vulgaris agglutinin-L (PHA-L). The associated glands of the olfactory mucosa, Bowman's glands, were stained with 13 lectins. While both the goblet cells and mucous nasal glands were stained with 8 lectins; five of them (WGA, s-WGA, STL, Vicia villosa agglutinin (VVA) and ECL) were mutually positive among the Bowman's glands, mucous nasal glands and the goblet cells. These findings indicate that the glycohistochemical characteristics of the free borders of both olfactory and respiratory epithelia are similar to each other, suggesting that secretions from the Bowman's glands and those of the goblet cells and mucous nasal glands are partially exchanged between the surface of two epithelia to contribute the functions of the respiratory epithelium and the olfactory receptor cells, respectively. PMID:24200894

  17. Non-conventional humanitarian interventions on Ebola outbreak crisis in West Africa: health, ethics and legal implications.

    PubMed

    Tambo, Ernest

    2014-01-01

    Due to the lack of Ebola outbreak early warning alert, preparedness, surveillance and response systems, the most deadly, complex and largest ever seen Ebola war has been devastating West African communities. The unparalleled Ebola tsunami has prompted interrogations into, and uncertainties about, the effectiveness and efficiency of national, regional and international community's illed- responses using conventional humanitarian control and containment approaches and methods. The late humanitarian and local non-government organisations emergency responses and challenges to curb transmission dynamics and stop the ongoing spread in the Ebola outbreak in West Africa have led to an unprecedented toll of 14,413 reported Ebola cases in eight countries since the outbreak began, with 5,177 reported deaths including 571 health-care workers and 325 died as 14 November 2014. These indications the need of further evaluation of monitoring as substantial proportion of infections outside the context of Ebola epicentres, Ebola health centres treatment and care, infection prevention and control quality assurance checks in these countries. At the same time, exhaustive efforts should target ensuring an sufficient supply of optimal personal protective equipment (PPE) to all Ebola treatment facilities, along with the provision of training and relevant guidelines to limit to the minimum possible level of risk. The continent hosts a big proportion of the world's wealth, yet its people live in abject poverty, with governments unable to feed and govern them effectively, and who are condemned to endure even darker moments with the Ebola outbreak in West Africa. Institutionalisation of practical and operational non-conventional emergency response models efficient health systems, and tailored programmes can clearly support to prevent, control and eventually stamp out Ebola geo-distribution in addition to population mental health services that are requisite to address the massive range of the

  18. Non-conventional humanitarian interventions on Ebola outbreak crisis in West Africa: health, ethics and legal implications.

    PubMed

    Tambo, Ernest

    2014-01-01

    Due to the lack of Ebola outbreak early warning alert, preparedness, surveillance and response systems, the most deadly, complex and largest ever seen Ebola war has been devastating West African communities. The unparalleled Ebola tsunami has prompted interrogations into, and uncertainties about, the effectiveness and efficiency of national, regional and international community's illed- responses using conventional humanitarian control and containment approaches and methods. The late humanitarian and local non-government organisations emergency responses and challenges to curb transmission dynamics and stop the ongoing spread in the Ebola outbreak in West Africa have led to an unprecedented toll of 14,413 reported Ebola cases in eight countries since the outbreak began, with 5,177 reported deaths including 571 health-care workers and 325 died as 14 November 2014. These indications the need of further evaluation of monitoring as substantial proportion of infections outside the context of Ebola epicentres, Ebola health centres treatment and care, infection prevention and control quality assurance checks in these countries. At the same time, exhaustive efforts should target ensuring an sufficient supply of optimal personal protective equipment (PPE) to all Ebola treatment facilities, along with the provision of training and relevant guidelines to limit to the minimum possible level of risk. The continent hosts a big proportion of the world's wealth, yet its people live in abject poverty, with governments unable to feed and govern them effectively, and who are condemned to endure even darker moments with the Ebola outbreak in West Africa. Institutionalisation of practical and operational non-conventional emergency response models efficient health systems, and tailored programmes can clearly support to prevent, control and eventually stamp out Ebola geo-distribution in addition to population mental health services that are requisite to address the massive range of the

  19. Odor Preference Learning and Memory Modify GluA1 Phosphorylation and GluA1 Distribution in the Neonate Rat Olfactory Bulb: Testing the AMPA Receptor Hypothesis in an Appetitive Learning Model

    ERIC Educational Resources Information Center

    Cui, Wen; Darby-King, Andrea; Grimes, Matthew T.; Howland, John G.; Wang, Yu Tian; McLean, John H.; Harley, Carolyn W.

    2011-01-01

    An increase in synaptic AMPA receptors is hypothesized to mediate learning and memory. AMPA receptor increases have been reported in aversive learning models, although it is not clear if they are seen with memory maintenance. Here we examine AMPA receptor changes in a cAMP/PKA/CREB-dependent appetitive learning model: odor preference learning in…

  20. Olfactory dysfunction, olfactory bulb pathology and urban air pollution

    PubMed Central

    Calderón-Garcidueñas, Lilian; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Osnaya, Norma; González-Maciel, Angelica; Reynoso-Robles, Rafael; Villarreal-Calderon, Rafael; Herritt, Lou; Brooks, Diane; Keefe, Sheyla; Palacios-Moreno, Juan; Villarreal-Calderon, Rodolfo; Torres-Jardón, Ricardo; Medina-Cortina, Humberto; Delgado-Chávez, Ricardo; Aiello-Mora, Mario; Maronpot, Robert R.; Doty, Richard L

    2010-01-01

    Mexico City (MC) residents are exposed to severe air pollution and exhibit olfactory bulb inflammation. We compared the olfactory function of individuals living under conditions of extreme air pollution to that of controls from a relatively clean environment and explore associations between olfaction scores, apolipoprotein E (APOE) status, and pollution exposure. The olfactory bulbs (OBs) of 35 MC and 9 controls 20.8 ± 8.5 y were assessed by light and electron microscopy. The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 62 MC / 25 controls 21.2 ±2.7 y. MC subjects had significantly lower UPSIT scores: 34.24 ± 0.42 versus controls 35.76 ± 0.40, p=0.03. Olfaction deficits were present in 35.5% MC and 12% of controls. MC APOE ε 4 carriers failed 2.4 ± 0.54 items in the 10-item smell identification scale from the UPSIT related to Alzheimer's disease, while APOE 2/3 and 3/3 subjects failed 1.36 ± 0.16 items, p = 0.01. MC residents exhibited OB endothelial hyperplasia, neuronal accumulation of particles (2/35), and immunoreactivity to beta amyloid βA42 (29/35) and/or α-synuclein (4/35) in neurons, glial cells and/or blood vessels. Ultrafine particles were present in OBs endothelial cytoplasm and basement membranes. Control OBs were unremarkable. Air pollution exposure is associated with olfactory dysfunction and OB pathology, APOE 4 may confer greater susceptibility to such abnormalities, and ultrafine particles could play a key role in the OB pathology. This study contributes to our understanding of the influences of air pollution on olfaction and its potential contribution to neurodegeneration. PMID:19297138

  1. Critical role of GFRα1 in the development and function of the main olfactory system.

    PubMed

    Marks, Carolyn; Belluscio, Leonardo; Ibáñez, Carlos F

    2012-11-28

    Glial cell line-derived neurotrophic factor (GDNF) and its receptor GFRα1 are prominently expressed in the olfactory epithelium (OE) and olfactory bulb (OB), but their importance for olfactory system development is completely unknown. We have investigated the consequences of GFRα1 deficiency for mouse olfactory system development and function. In the OE, GFRα1 was expressed in basal precursors, immature olfactory sensory neurons (OSNs), and olfactory ensheathing cells (OECs), but was excluded from mature OSNs. The OE of newborn Gfra1 knock-out mice was thinner and contained fewer OSNs, but more dividing precursors, suggesting deficient neurogenesis. Immature OSN axon bundles were enlarged and associated OECs increased, indicating impaired migration of OECs and OSN axons. In the OB, GFRα1 was expressed in immature OSN axons and OECs of the nerve layer, as well as mitral and tufted cells, but was excluded from GABAergic interneurons. In newborn knock-outs, the nerve layer was dramatically reduced, exhibiting fewer axons and OECs. Bulbs were smaller and presented fewer and disorganized glomeruli and a significant reduction in mitral cells. Numbers of tyrosine hydroxylase-, calbindin-, and calretinin-expressing interneurons were also reduced in newborn mice lacking Gfra1. At birth, the OE and OB of Gdnf knock-out mice displayed comparable phenotypes. Similar deficits were also found in adult heterozygous Gfra1(+/-) mutants, which in addition displayed diminished responses in behavioral tests of olfactory function. We conclude that GFRα1 is critical for the development and function of the main olfactory system, contributing to the development and allocation of all major classes of neurons and glial cells.

  2. Notch1 activity in the olfactory bulb is odour-dependent and contributes to olfactory behaviour.

    PubMed

    Brai, Emanuele; Marathe, Swananda; Zentilin, Lorena; Giacca, Mauro; Nimpf, Johannes; Kretz, Robert; Scotti, Alessandra; Alberi, Lavinia

    2014-11-01

    Notch signalling plays an important role in synaptic plasticity, learning and memory functions in both Drosophila and rodents. In this paper, we report that this feature is not restricted to hippocampal networks but also involves the olfactory bulb (OB). Odour discrimination and olfactory learning in rodents are essential for survival. Notch1 expression is enriched in mitral cells of the mouse OB. These principal neurons are responsive to specific input odorants and relay the signal to the olfactory cortex. Olfactory stimulation activates a subset of mitral cells, which show an increase in Notch activity. In Notch1cKOKln mice, the loss of Notch1 in mitral cells affects the magnitude of the neuronal response to olfactory stimuli. In addition, Notch1cKOKln mice display reduced olfactory aversion to propionic acid as compared to wildtype controls. This indicates, for the first time, that Notch1 is involved in olfactory processing and may contribute to olfactory behaviour.

  3. Chinook salmon (Oncorhynchus tshawytscha) and rainbow trout (Oncorhynchus mykiss) exposed to copper: Neurophysiological and histological effects on the olfactory system

    SciTech Connect

    Hansen, J.A.; Rose, J.D.; Jenkins, R.A.; Gerow, K.G.; Bergman, H.L.

    1999-09-01

    Olfactory epithelial structure and olfactory bulb neurophysiological responses were measured in chinook salmon and rainbow trout in response to 25 to 300 {micro}g copper (Cu)/L. Using confocal laser scanning microscopy, the number of olfactory receptors was significantly reduced in chinook salmon exposed to {ge}50 {micro}g Cu/L and in rainbow trout exposed to {ge}200 {micro}g cu/L for 1 h. The number of receptors was significantly reduced in both species following exposure to 25 {micro}g Cu/L for 4 h. Transmission electron microscopy of olfactory epithelial tissue indicated that the loss of receptors was from cellular necrosis. Olfactory bulk electroencephalogram (EEG) responses to 10{sup {minus}3} M L-serine were initially reduced by all Cu concentrations but were virtually eliminated in chinook salmon exposed to {ge}50 {micro}g Cu/L and in rainbow trout exposed to {ge}200 {micro}g Cu/L within 1 h of exposure. Following Cu exposure, EEG response recovery rates were slower in fish exposed to higher Cu concentrations. The higher sensitivity of the chinook salmon olfactory system to Cu-induced histological damage and neurophysiological impairment parallels the relative species sensitivity observed in behavioral avoidance experiments. This difference in species sensitivity may reduce the survival and reproductive potential of chinook salmon compared with that of rainbow trout in Cu-contaminated waters.

  4. Postnatal odorant exposure induces peripheral olfactory plasticity at the cellular level.

    PubMed

    Cadiou, Hervé; Aoudé, Imad; Tazir, Bassim; Molinas, Adrien; Fenech, Claire; Meunier, Nicolas; Grosmaitre, Xavier

    2014-04-01

    Mammalian olfactory sensory neurons (OSNs) form the primary elements of the olfactory system. Inserted in the olfactory mucosa lining of the nasal cavity, they are exposed to the environment and their lifespan is brief. Several reports say that OSNs are regularly regenerated during the entire life and that odorant environment affects the olfactory epithelium. However, little is known about the impact of the odorant environment on OSNs at the cellular level and more precisely in the context of early postnatal olfactory exposure. Here we exposed MOR23-green fluorescent protein (GFP) and M71-GFP mice to lyral or acetophenone, ligands for MOR23 or M71, respectively. Daily postnatal exposure to lyral induces plasticity in the population of OSNs expressing MOR23. Their density decreases after odorant exposure, whereas the amount of MOR23 mRNA and protein remain stable in the whole epithelium. Meanwhile, quantitative PCR indicates that each MOR23 neuron has higher levels of olfactory receptor transcripts and also expresses more CNGA2 and phosphodiesterase 1C, fundamental olfactory transduction pathway proteins. Transcript levels return to baseline after 4 weeks recovery. Patch-clamp recordings reveal that exposed MOR23 neurons respond to lyral with higher sensitivity and broader dynamic range while the responses' kinetics were faster. These effects are specific to the odorant-receptor pair lyral-MOR23: there was no effect of acetophenone on MOR23 neurons and no effect of acetophenone and lyral on the M71 population. Together, our results clearly demonstrate that OSNs undergo specific anatomical, molecular, and functional adaptation when chronically exposed to odorants in the early stage of life.

  5. A novel olfactory pathway is essential for fast and efficient blood-feeding in mosquitoes.

    PubMed

    Jung, Je Won; Baeck, Seung-Jae; Perumalsamy, Haribalan; Hansson, Bill S; Ahn, Young-Joon; Kwon, Hyung Wook

    2015-08-26

    In mosquitoes, precise and efficient finding of a host animal is crucial for survival. One of the poorly understood aspects of mosquito blood-feeding behavior is how these insects target an optimal site in order to penetrate the skin and blood vessels without alerting the host animal. Here we provide new findings that a piercing structure of the mouthpart of the mosquitoes, the stylet, is an essential apparatus for the stage in blood feeding. Indeed, the stylet possesses a number of sensory hairs located at the tip of the stylet. These hairs house olfactory receptor neurons that express two conventional olfactory receptors of Aedes aegypti (AaOrs), AaOr8 and AaOr49, together with the odorant co-receptor (AaOrco). In vivo calcium imaging using transfected cell lines demonstrated that AaOr8 and AaOr49 were activated by volatile compounds present in blood. Inhibition of gene expression of these AaOrs delayed blood feeding behaviors of the mosquito. Taken together, we identified olfactory receptor neurons in the stylet involved in mosquito blood feeding behaviors, which in turn indicates that olfactory perception in the stylet is necessary and sufficient for mosquitoes to find host blood in order to rapidly acquire blood meals from a host animal.

  6. A novel olfactory pathway is essential for fast and efficient blood-feeding in mosquitoes

    PubMed Central

    Won Jung, Je; Baeck, Seung-Jae; Perumalsamy, Haribalan; Hansson, Bill S.; Ahn, Young-Joon; Kwon, Hyung Wook

    2015-01-01

    In mosquitoes, precise and efficient finding of a host animal is crucial for survival. One of the poorly understood aspects of mosquito blood-feeding behavior is how these insects target an optimal site in order to penetrate the skin and blood vessels without alerting the host animal. Here we provide new findings that a piercing structure of the mouthpart of the mosquitoes, the stylet, is an essential apparatus for the stage in blood feeding. Indeed, the stylet possesses a number of sensory hairs located at the tip of the stylet. These hairs house olfactory receptor neurons that express two conventional olfactory receptors of Aedes aegypti (AaOrs), AaOr8 and AaOr49, together with the odorant co-receptor (AaOrco). In vivo calcium imaging using transfected cell lines demonstrated that AaOr8 and AaOr49 were activated by volatile compounds present in blood. Inhibition of gene expression of these AaOrs delayed blood feeding behaviors of the mosquito. Taken together, we identified olfactory receptor neurons in the stylet involved in mosquito blood feeding behaviors, which in turn indicates that olfactory perception in the stylet is necessary and sufficient for mosquitoes to find host blood in order to rapidly acquire blood meals from a hos