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Sample records for insect olfactory environment

  1. Physical Processes and Real-Time Chemical Measurement of the Insect Olfactory Environment

    PubMed Central

    Abrell, Leif; Hildebrand, John G.

    2009-01-01

    Odor-mediated insect navigation in airborne chemical plumes is vital to many ecological interactions, including mate finding, flower nectaring, and host locating (where disease transmission or herbivory may begin). After emission, volatile chemicals become rapidly mixed and diluted through physical processes that create a dynamic olfactory environment. This review examines those physical processes and some of the analytical technologies available to characterize those behavior-inducing chemical signals at temporal scales equivalent to the olfactory processing in insects. In particular, we focus on two areas of research that together may further our understanding of olfactory signal dynamics and its processing and perception by insects. First, measurement of physical atmospheric processes in the field can provide insight into the spatiotemporal dynamics of the odor signal available to insects. Field measurements in turn permit aspects of the physical environment to be simulated in the laboratory, thereby allowing careful investigation into the links between odor signal dynamics and insect behavior. Second, emerging analytical technologies with high recording frequencies and field-friendly inlet systems may offer new opportunities to characterize natural odors at spatiotemporal scales relevant to insect perception and behavior. Characterization of the chemical signal environment allows the determination of when and where olfactory-mediated behaviors may control ecological interactions. Finally, we argue that coupling of these two research areas will foster increased understanding of the physicochemical environment and enable researchers to determine how olfactory environments shape insect behaviors and sensory systems. PMID:18548311

  2. 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

  3. Antennal olfactory sensilla responses to insect chemical repellents in the common bed bug, Cimex lectularius.

    PubMed

    Liu, Feng; Haynes, Kenneth F; Appel, Arthur G; Liu, Nannan

    2014-06-01

    Populations of the common bed bug Cimex lectularius (Hemiptera; Cimicidae), a temporary ectoparasite on both humans and animals, have surged in many developed countries. Similar to other haematophagous arthropods, C. lectularius relies on its olfactory system to detect semiochemicals in the environment, including both attractants and repellents. To elucidate the olfactory responses of the common bed bug to commonly used insect chemical repellents, particularly haematophagous repellents, we investigated the neuronal responses of individual olfactory sensilla in C. lectularius' antennae to 52 insect chemical repellents, both synthetic and botanic. Different types of sensilla displayed highly distinctive response profiles. While C sensilla did not respond to any of the insect chemical repellents, Dγ sensilla proved to be the most sensitive in response to terpene-derived insect chemical repellents. Different chemical repellents elicited neuronal responses with differing temporal characteristics, and the responses of the olfactory sensilla to the insect chemical repellents were dose-dependent, with an olfactory response to the terpene-derived chemical repellent, but not to the non-terpene-derived chemical repellents. Overall, this study furnishes a comprehensive map of the olfactory response of bed bugs to commonly used insect chemical repellents, providing useful information for those developing new agents (attractants or repellents) for bed bug control.

  4. Insect olfactory receptors: contributions of molecular biology to chemical ecology.

    PubMed

    Jacquin-Joly, Emmanuelle; Merlin, Christine

    2004-12-01

    Our understanding of the molecular basis of chemical signal recognition in insects has been greatly expanded by the recent discovery of olfactory receptors (Ors). Since the discovery of the complete repertoire of Drosophila melanogaster Ors, candidate Ors have been identified from at least 12 insect species from four orders (Coleoptera, Lepidoptera, Diptera, and Hymenoptera), including species of economic or medical importance. Although all Ors share the same G-protein coupled receptor structure with seven transmembrane domains, they present poor sequence homologies within and between species, and have been identified mainly through genomic data analyses. To date, D. melanogaster remains the only insect species where Ors have been extensively studied, from expression pattern establishment to functional investigations. These studies have confirmed several observations made in vertebrates: one Or type is selectively expressed in a subtype of olfactory receptor neurons, and one olfactory neuron expresses only one type of Or. In addition, all olfactory neurons expressing one Or type converge to the same glomerulus in the antennal lobe. The olfactory mechanism, thus, appears to be conserved between insects and vertebrates. Although Or functional studies are in their initial stages in insects (mainly Drosophila), insects appear to be good models to establish fundamental concepts of olfaction with the development of powerful genetic, imaging, and behavioral tools. This new field of study will greatly contribute to the understanding of insect chemical communication mechanisms, particularly with agricultural pests and disease vectors, and could result in future strategies to reduce their negative effects.

  5. Using Insect Electroantennogram Sensors on Autonomous Robots for Olfactory Searches

    PubMed Central

    Martinez, Dominique; Arhidi, Lotfi; Demondion, Elodie; Masson, Jean-Baptiste; Lucas, Philippe

    2014-01-01

    Robots designed to track chemical leaks in hazardous industrial facilities1 or explosive traces in landmine fields2 face the same problem as insects foraging for food or searching for mates3: the olfactory search is constrained by the physics of turbulent transport4. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity5-6, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones7 but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells8 or toxic and illicit substances9-11. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors12. The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies13. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration14 or using nanostructured gas sensors that mimic insect antennae15

  6. Using insect electroantennogram sensors on autonomous robots for olfactory searches.

    PubMed

    Martinez, Dominique; Arhidi, Lotfi; Demondion, Elodie; Masson, Jean-Baptiste; Lucas, Philippe

    2014-08-04

    Robots designed to track chemical leaks in hazardous industrial facilities or explosive traces in landmine fields face the same problem as insects foraging for food or searching for mates: the olfactory search is constrained by the physics of turbulent transport. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells or toxic and illicit substances. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors. The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration or using nanostructured gas sensors that mimic insect antennae.

  7. Olfactory Mechanisms for Discovery of Odorants to Reduce Insect-Host Contact

    PubMed Central

    Clark, Jonathan T.; Ray, Anandasankar

    2016-01-01

    Insects have developed highly sophisticated and sensitive olfactory systems to find animal or plant hosts for feeding. Some insects vector pathogens that cause diseases in hundreds of millions of people and destroy billions of dollars of food products every year. There is great interest, therefore, in understanding how the insect olfactory system can be manipulated to reduce their contact with hosts. Here, we review recent advances in our understanding of insect olfactory detection mechanisms, which may serve as a foundation for designing insect control programs based on manipulation of their behaviors by using odorants. Because every insect species has a unique set of olfactory receptors and olfactory-mediated behaviors, we focus primarily on general principles of odor detection that potentially apply to most insects. While these mechanisms have emerged from studies on model systems for study of insect olfaction, such as Drosophila melanogaster, they provide a foundation for discovery of odorants to repel insects or reduce host-seeking behavior. PMID:27628342

  8. Early olfactory experience induces structural changes in the primary olfactory center of an insect brain.

    PubMed

    Arenas, A; Giurfa, M; Sandoz, J C; Hourcade, B; Devaud, J M; Farina, W M

    2012-03-01

    The antennal lobe (AL) is the first olfactory center of the insect brain and is constituted of different functional units, the glomeruli. In the AL, odors are coded as spatiotemporal patterns of glomerular activity. In honeybees, olfactory learning during early adulthood modifies neural activity in the AL on a long-term scale and also enhances later memory retention. By means of behavioral experiments, we first verified that olfactory learning between the fifth and eighth day of adulthood induces better retention performances at a late adult stage than the same experience acquired before or after this period. We checked that the specificity of memory for the odorants used was improved. We then studied whether such early olfactory learning also induces long-term structural changes in the AL consistent with the formation of long-term olfactory memories. We also measured the volume of 15 identified glomeruli in the ALs of 17-day-old honeybees that either experienced an odor associated with sucrose solution between the fifth and eighth day of adulthood or were left untreated. We found that early olfactory experience induces glomerulus-selective increases in volume that were specific to the learned odor. By comparing our volumetric measures with calcium-imaging recordings from a previous study, performed in 17-day-old bees subjected to the same treatment and experimental conditions, we found that glomeruli that showed structural changes after early learning were those that exhibited a significant increase in neural activity. Our results make evident a correlation between structural and functional changes in the AL following early olfactory learning.

  9. Neuroethology of Olfactory-Guided Behavior and Its Potential Application in the Control of Harmful Insects

    PubMed Central

    Reisenman, Carolina E.; Lei, Hong; Guerenstein, Pablo G.

    2016-01-01

    Harmful insects include pests of crops and storage goods, and vectors of human and animal diseases. Throughout their history, humans have been fighting them using diverse methods. The fairly recent development of synthetic chemical insecticides promised efficient crop and health protection at a relatively low cost. However, the negative effects of those insecticides on human health and the environment, as well as the development of insect resistance, have been fueling the search for alternative control tools. New and promising alternative methods to fight harmful insects include the manipulation of their behavior using synthetic versions of “semiochemicals”, which are natural volatile and non-volatile substances involved in the intra- and/or inter-specific communication between organisms. Synthetic semiochemicals can be used as trap baits to monitor the presence of insects, so that insecticide spraying can be planned rationally (i.e., only when and where insects are actually present). Other methods that use semiochemicals include insect annihilation by mass trapping, attract-and- kill techniques, behavioral disruption, and the use of repellents. In the last decades many investigations focused on the neural bases of insect's responses to semiochemicals. Those studies help understand how the olfactory system detects and processes information about odors, which could lead to the design of efficient control tools, including odor baits, repellents or ways to confound insects. Here we review our current knowledge about the neural mechanisms controlling olfactory responses to semiochemicals in harmful insects. We also discuss how this neuroethology approach can be used to design or improve pest/vector management strategies. PMID:27445858

  10. Neuroethology of Olfactory-Guided Behavior and Its Potential Application in the Control of Harmful Insects.

    PubMed

    Reisenman, Carolina E; Lei, Hong; Guerenstein, Pablo G

    2016-01-01

    Harmful insects include pests of crops and storage goods, and vectors of human and animal diseases. Throughout their history, humans have been fighting them using diverse methods. The fairly recent development of synthetic chemical insecticides promised efficient crop and health protection at a relatively low cost. However, the negative effects of those insecticides on human health and the environment, as well as the development of insect resistance, have been fueling the search for alternative control tools. New and promising alternative methods to fight harmful insects include the manipulation of their behavior using synthetic versions of "semiochemicals", which are natural volatile and non-volatile substances involved in the intra- and/or inter-specific communication between organisms. Synthetic semiochemicals can be used as trap baits to monitor the presence of insects, so that insecticide spraying can be planned rationally (i.e., only when and where insects are actually present). Other methods that use semiochemicals include insect annihilation by mass trapping, attract-and- kill techniques, behavioral disruption, and the use of repellents. In the last decades many investigations focused on the neural bases of insect's responses to semiochemicals. Those studies help understand how the olfactory system detects and processes information about odors, which could lead to the design of efficient control tools, including odor baits, repellents or ways to confound insects. Here we review our current knowledge about the neural mechanisms controlling olfactory responses to semiochemicals in harmful insects. We also discuss how this neuroethology approach can be used to design or improve pest/vector management strategies.

  11. 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

  12. Olfactory Environment Design for Human Spaceflight

    NASA Astrophysics Data System (ADS)

    Welch, C. S.; Holland, F. J.

    2002-01-01

    Smell is usually deemed the least important of the five senses. To contradict this assertion, however, there is no shortage of scientific literature which concludes that olfaction is of very great significance to humans. Odours have been shown to have a variety of effects on humans, and are capable of changing both behaviour and cognitive processing in ways that we are frequently completely unconscious of. Examples of this include alertness, alteration of mood, capacity for ideation and intellectual performance. To date, the design of human spacecraft has concentrated on making their olfactory environments, where possible, `odour neutral' - that is ensuring that all unpleasant and/or offensive odours are removed. Here it suggested that spacecraft (and other extraterrestrial facilities for human inhabitation) might benefit from having their olfactory environments designed to be `odour positive', that is to use odours and olfaction for the positive benefit of their residents. This paper presents a summary of current olfactory research and considers both its positive and negative implications for humans in space. It then discusses `odour positive' design of spacecraft olfactory environments and the possible benefits accruing from this approach before examining its implications for the architecture of spacecraft environmental control systems.

  13. An overview of odorant-binding protein functions in insect peripheral olfactory reception.

    PubMed

    Fan, J; Francis, F; Liu, Y; Chen, J L; Cheng, D F

    2011-12-08

    Insect olfactory perception involves many aspects of insect life, and can directly or indirectly evoke either individual or group behaviors. Insect olfactory receptors and odorant-binding proteins (OBPs) are considered to be crucial to insect-specific and -sensitive olfaction. Although the mechanisms of interaction between OBPs or OBP/ligand complex with olfactory receptors are still not well understood, it has been shown that many OBPs contribute to insect olfactory perception at various levels. Some of these are numerous and divergent members in OBP family; expression in the olfactory organ at high concentration; a variety of combinational patterns between different OBPs and ligands, but exclusive affinity for one OBP to specific binding ligands; complicated interactions between OBP/ligand complex and transmembrane proteins (olfactory receptors or sensory neuron membrane proteins). First, we review OBPs' ligand-binding property based on OBP structural research and ligand-binding test; then, we review current progress around the points cited above to show the role of such proteins in insect olfactory signal transmission; finally, we discuss applications based on insect OBP research.

  14. Insects groom their antennae to enhance olfactory acuity

    PubMed Central

    Böröczky, Katalin; Wada-Katsumata, Ayako; Batchelor, Dale; Zhukovskaya, Marianna; Schal, Coby

    2013-01-01

    Grooming, a common behavior in animals, serves the important function of removing foreign materials from body surfaces. When antennal grooming was prevented in the American cockroach, Periplaneta americana, field emission gun scanning electron microscopy images revealed that an unstructured substance accumulated on nongroomed antennae, covering sensillar pores, but not on groomed antennae of the same individuals. Gas chromatography analysis of antennal extracts showed that over a 24-h period nongroomed antennae accumulated three to four times more cuticular hydrocarbons than groomed antennae. Moreover, nongroomed antennae accumulated significantly more environmental contaminants from surfaces (stearic acid) and from air (geranyl acetate) than groomed antennae. We hypothesized that the accumulation of excess native cuticular hydrocarbons on the antennae would impair olfactory reception. Electroantennogram experiments and single-sensillum recordings supported this hypothesis: antennae that were prevented from being groomed were significantly less responsive than groomed antennae to the sex pheromone component periplanone-B, as well as to the general odorants geranyl acetate and hexanol. We therefore conclude that antennal grooming removes excess native cuticular lipids and foreign chemicals that physically and/or chemically interfere with olfaction, and thus maintains the olfactory acuity of the antennae. Similar experimental manipulations of the German cockroach (Blattella germanica), carpenter ant (Camponotus pennsylvanicus), and the housefly (Musca domestica), which use different modes of antennal grooming, support the hypothesis that antennal grooming serves a similar function in a wide range of insect taxa. PMID:23382193

  15. Olfactory Mechanisms for Discovery of Odorants to Reduce Insect-Host Contact.

    PubMed

    Clark, Jonathan T; Ray, Anandasankar

    2016-09-01

    Insects have developed highly sophisticated and sensitive olfactory systems to find animal or plant hosts for feeding. Some insects vector pathogens that cause diseases in hundreds of millions of people and destroy billions of dollars of food products every year. There is great interest, therefore, in understanding how the insect olfactory system can be manipulated to reduce their contact with hosts. Here, we review recent advances in our understanding of insect olfactory detection mechanisms, which may serve as a foundation for designing insect control programs based on manipulation of their behaviors by using odorants. Because every insect species has a unique set of olfactory receptors and olfactory-mediated behaviors, we focus primarily on general principles of odor detection that potentially apply to most insects. While these mechanisms have emerged from studies on model systems for study of insect olfaction, such as Drosophila melanogaster, they provide a foundation for discovery of odorants to repel vector insects or reduce their host-seeking behavior.

  16. Olfactory Stimuli Increase Presence in Virtual Environments

    PubMed Central

    Munyan, Benson G.; Neer, Sandra M.; Beidel, Deborah C.; Jentsch, Florian

    2016-01-01

    Background Exposure therapy (EXP) is the most empirically supported treatment for anxiety and trauma-related disorders. EXP consists of repeated exposure to a feared object or situation in the absence of the feared outcome in order to extinguish associated anxiety. Key to the success of EXP is the need to present the feared object/event/situation in as much detail and utilizing as many sensory modalities as possible, in order to augment the sense of presence during exposure sessions. Various technologies used to augment the exposure therapy process by presenting multi-sensory cues (e.g., sights, smells, sounds). Studies have shown that scents can elicit emotionally charged memories, but no prior research has examined the effect of olfactory stimuli upon the patient’s sense of presence during simulated exposure tasks. Methods 60 adult participants navigated a mildly anxiety-producing virtual environment (VE) similar to those used in the treatment of anxiety disorders. Participants had no autobiographical memory associated with the VE. State anxiety, Presence ratings, and electrodermal (EDA) activity were collected throughout the experiment. Results Utilizing a Bonferroni corrected Linear Mixed Model, our results showed statistically significant relationships between olfactory stimuli and presence as assessed by both the Igroup Presence Questionnaire (IPQ: R2 = 0.85, (F(3,52) = 6.625, p = 0.0007) and a single item visual-analogue scale (R2 = 0.85, (F(3,52) = 5.382, p = 0.0027). State anxiety was unaffected by the presence or absence of olfactory cues. EDA was unaffected by experimental condition. Conclusion Olfactory stimuli increase presence in virtual environments that approximate those typical in exposure therapy, but did not increase EDA. Additionally, once administered, the removal of scents resulted in a disproportionate decrease in presence. Implications for incorporating the use of scents to increase the efficacy of exposure therapy is discussed. PMID

  17. Olfactory coding in the insect brain: data and conjectures

    PubMed Central

    Galizia, C Giovanni

    2014-01-01

    Much progress has been made recently in understanding how olfactory coding works in insect brains. Here, I propose a wiring diagram for the major steps from the first processing network (the antennal lobe) to behavioral readout. I argue that the sequence of lateral inhibition in the antennal lobe, non-linear synapses, threshold-regulating gated spring network, selective lateral inhibitory networks across glomeruli, and feedforward inhibition to the lateral protocerebrum cover most of the experimental results from different research groups and model species. I propose that the main difference between mushroom bodies and the lateral protocerebrum is not about learned vs. innate behavior. Rather, mushroom bodies perform odor identification, whereas the lateral protocerebrum performs odor evaluation (both learned and innate). I discuss the concepts of labeled line and combinatorial coding and postulate that, under restrictive experimental conditions, these networks lead to an apparent existence of ‘labeled line’ coding for special odors. Modulatory networks are proposed as switches between different evaluating systems in the lateral protocerebrum. A review of experimental data and theoretical conjectures both contribute to this synthesis, creating new hypotheses for future research. PMID:24698302

  18. Morphology and physiology of the olfactory system of blood-feeding insects.

    PubMed

    Guidobaldi, F; May-Concha, I J; Guerenstein, P G

    2014-01-01

    Several blood-feeding (hematophagous) insects are vectors of a number of diseases including dengue, Chagas disease and leishmaniasis which persistently affect public health throughout Latin America. The vectors of those diseases include mosquitoes, triatomine bugs and sandflies. As vector control is an efficient way to prevent these illnesses it is important to understand the sensory biology of those harmful insects. We study the physiology of the olfactory system of those insects and apply that knowledge on the development of methods to manipulate their behavior. Here we review some of the latest information on insect olfaction with emphasis on hematophagous insects. The insect olfactory sensory neurons are housed inside hair-like organs called sensilla which are mainly distributed on the antenna and mouthparts. The identity of many of the odor compounds that those neurons detect are already known in hematophagous insects. They include several constituents of host (vertebrate) odor, sex, aggregation and alarm pheromones, and compounds related to egg-deposition behavior. Recent work has contributed significant knowledge on how odor information is processed in the insect first odor-processing center in the brain, the antennal lobe. The quality, quantity, and temporal features of the odor stimuli are encoded by the neural networks of the antennal lobe. Information regarding odor mixtures is also encoded. While natural mixtures evoke strong responses, synthetic mixtures that deviate from their natural counterparts in terms of key constituents or proportions of those constituents evoke weaker responses. The processing of olfactory information is largely unexplored in hematophagous insects. However, many aspects of their olfactory behavior are known. As in other insects, responses to relevant single odor compounds are weak while natural mixtures evoke strong responses. Future challenges include studying how information about odor mixtures is processed in their brain

  19. 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

  20. Olfactory disruption: towards controlling important insect vectors of disease

    USDA-ARS?s Scientific Manuscript database

    Chemical repellents are used to decrease contacts between insect disease vectors and their hosts, thus reducing the probability of disease transmission. The molecular mechanisms by which repellents have their effects are poorly understood and remain a controversial topic. Here we present recent re...

  1. Positive Allosteric Modulation of Insect Olfactory Receptor Function by ORco Agonists

    PubMed Central

    Tsitoura, Panagiota; Iatrou, Kostas

    2016-01-01

    Insect olfactory receptors (ORs) are heteromeric ligand-gated cation channels composed of a common olfactory receptor subunit (ORco) and a variable subunit (ORx) of as yet unknown structures and undetermined stoichiometries. In this study, we examined the allosteric modulation exerted on Anopheles gambiae heteromeric ORx/ORco olfactory receptors in vitro by a specific class of ORco agonists (OAs) comprising ORcoRAM2 and VUAA1. High OA concentrations produced stronger functional responses in cells expressing heteromeric receptor channels relative to cells expressing ORco alone. These OA-induced responses of ORx/ORco channels were also notably much stronger than those obtained upon administration of ORx-specific ligands to the same receptors. Most importantly, small concentrations of OAs were found to act as strong potentiators of ORx/ORco function, increasing dramatically both the efficacy and potency of ORx-specific odorants. These results suggest that insect heteromeric ORs are highly dynamic complexes adopting different conformations that change in a concerted fashion as a result of the interplay between the subunits of the oligomeric assemblies, and that allosteric modulation may constitute an important element in the modulation and fining tuning of olfactory reception function. PMID:28018173

  2. Olfactory disruption: toward controlling important insect vectors of disease.

    PubMed

    Sparks, Jackson T; Bohbot, Jonathan D; Dickens, Joseph C

    2015-01-01

    Chemical repellents are used to decrease contacts between insect disease vectors and their hosts, thus reducing the probability of disease transmission. The molecular mechanisms by which repellents have their effects are poorly understood and remain a controversial topic. Here, we present recent results of studies aimed at a more thorough understanding of the mode of action of repellents and discuss the implications of these findings for future research and development of novel or improved repellents. © 2015 Elsevier Inc. All rights reserved.

  3. Insects in a changing environment

    SciTech Connect

    Harrington, R.; Stork, N.

    1995-12-31

    This book, from a 1993 symposium, focuses on current, anthropogenic changes in insect populations using five major sections: introduction; changes in climate; changes in gas/pollutant levels; changes in land use; and a section of shorter papers. The effects of climate change on insects are assessed using techniques ranging from fossil evidence to simulation models to remote sensing. The section on changes in gas levels addresses a series of individually studies of insect responses to atmospheric gases and other pollutants. The section focusing on the effects of environmental change on insects is well documented.

  4. Early Olfactory Environment Influences Social Behaviour in Adult Octodon degus

    PubMed Central

    Márquez, Natalia; Martínez-Harms, Jaime; Vásquez, Rodrigo A.; Mpodozis, Jorge

    2015-01-01

    We evaluated the extent to which manipulation of early olfactory environment can influence social behaviours in the South American Hystricognath rodent Octodon degus. The early olfactory environment of newborn degus was manipulated by scenting all litter members with eucalyptol during the first month of life. The social behaviour of sexually mature animals (5–7 months old) towards conspecifics was then assessed using a y-maze to compare the response of control (naïve) and treated animals to two different olfactory configurations (experiment 1): (i) a non-familiarized conspecific impregnated with eucalyptol (eucalyptol arm) presented against (ii) a non-familiarized unscented conspecific (control arm). In addition, in dyadic encounters, we assessed the behaviour of control and eucalyptol treated animals towards a non-familiarized conspecific scented with eucalyptol (experiment 2). We found that control subjects explored and spent significantly less time in the eucalyptol arm, indicating neophobic behaviours towards the artificially scented conspecific. Treated subjects explored and spent similar time in both arms of the maze, showing the same interest for both olfactory stimuli presented. During dyadic encounters in experiment 2, an interaction effect between early experience and sex was observed. Control males escaped and avoided their scented partner more frequently than eucalyptol treated male subjects and than females. Both groups did not differ in the exploration of their scented partners, suggesting that avoidance within agonistic context does not relate to neophobic behaviours. Our results suggest that the exposure to eucalyptol during early ontogeny decreases evasive behaviours within an agonistic context as a result of olfactory learning. Altogether, these results indicate that olfactory cues learned in early ontogeny can influence olfactory-guided behaviours in adult degus. PMID:25671542

  5. Advances in the identification and characterization of olfactory receptors in insects.

    PubMed

    Montagné, Nicolas; de Fouchier, Arthur; Newcomb, Richard D; Jacquin-Joly, Emmanuelle

    2015-01-01

    Olfactory receptors (ORs) are the key elements of the molecular machinery responsible for the detection of odors in insects. Since their initial discovery in Drosophila melanogaster at the beginning of the twenty-first century, insect ORs have been the focus of intense research, both for fundamental knowledge of sensory systems and for their potential as novel targets for the development of products that could impact harmful behaviors of crop pests and disease vectors. In recent years, studies on insect ORs have entered the genomic era, with an ever-increasing number of OR genes being characterized every year through the sequencing of genomes and transcriptomes. With the upcoming release of genomic sequences from hundreds of insect species, the insect OR family could very well become the largest multigene family known. This extremely rapid identification of ORs in many insects is driving the necessity for the development of high-throughput technologies that will allow the identification of ligands for this unprecedented number of receptors. Moreover, such technologies will also be important for the development of agonists or antagonists that could be used in the fight against pest insects. © 2015 Elsevier Inc. All rights reserved.

  6. Unexpected effects of sublethal doses of insecticide on the peripheral olfactory response and sexual behavior in a pest insect.

    PubMed

    Lalouette, Lisa; Pottier, Marie-Anne; Wycke, Marie-Anne; Boitard, Constance; Bozzolan, Françoise; Maria, Annick; Demondion, Elodie; Chertemps, Thomas; Lucas, Philippe; Renault, David; Maibeche, Martine; Siaussat, David

    2016-02-01

    Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive--also called hermetic--effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure.

  7. Olfactory Carbon Dioxide Detection by Insects and Other Animals

    PubMed Central

    Jones, Walton

    2013-01-01

    Carbon dioxide is a small, relatively inert, but highly volatile gas that not only gives beer its bubbles, but that also acts as one of the primary driving forces of anthropogenic climate change. While beer brewers experiment with the effects of CO2 on flavor and climate scientists are concerned with global changes to ambient CO2 levels that take place over the course of decades, many animal species are keenly aware of changes in CO2 concentration that occur much more rapidly and on a much more local scale. Although imperceptible to us, these small changes in CO2 concentration can indicate imminent danger, signal overcrowding, and point the way to food. Here I review several of these CO2-evoked behaviors and compare the systems insects, nematodes, and vertebrates use to detect environmental CO2. PMID:23456329

  8. Insect-like olfactory adaptations in the terrestrial giant robber crab.

    PubMed

    Stensmyr, Marcus C; Erland, Susanne; Hallberg, Eric; Wallén, Rita; Greenaway, Peter; Hansson, Bill S

    2005-01-26

    The robber crab (Birgus latro), also known as the coconut crab, is the world's largest land-living arthropod, with a weight reaching 4 kg and a length of over half a meter. Apart from the marine larval stage, this crab is fully terrestrial, and will actually drown if submerged in water. A transition from sea to land raises dramatically new demands on the sensory equipment of an animal. In olfaction, the stimulus changes from hydrophilic molecules in aqueous solution to mainly hydrophobic in the gaseous phase. The olfactory system of land crabs thus represents an excellent opportunity for investigating the effects of the transition from sea to land. Have land crabs come to the same solutions as other terrestrial animals, or is their olfactory sense characterized by unique innovations? Here, we show that the robber crab has evolved an olfactory sense with a high degree of resemblance to the insect system. The similarities extend to physiological, behavioral, and morphological characters. The insect nose of the robber crab is a striking example of convergent evolution and nicely illustrates how similar selection pressures result in similar adaptation.

  9. Pest Insect Olfaction in an Insecticide-Contaminated Environment: Info-Disruption or Hormesis Effect

    PubMed Central

    Tricoire-Leignel, Hélène; Thany, Steeve Hervé; Gadenne, Christophe; Anton, Sylvia

    2012-01-01

    Most animals, including pest insects, live in an “odor world” and depend strongly on chemical stimuli to get information on their biotic and abiotic environment. Although integrated pest management strategies including the use of insect growth regulators (IGRs) are increasingly developed, most insect pest treatments rely on neurotoxic chemicals. These molecules are known to disrupt synaptic transmission, affecting therefore sensory systems. The wide-spread use of neurotoxic insecticides and the growing use of IGRs result in residual accumulation of low concentrations in the environment. These insecticide residues could act as an “info-disruptor” by modifying the chemical communication system, and therefore decrease chances of reproduction in target insects. However, residues can also induce a non-expected hormesis effect by enhancing reproduction abilities. Low insecticide doses might thus induce adaptive processes in the olfactory pathway of target insects, favoring the development of resistance. The effect of sublethal doses of insecticides has mainly been studied in beneficial insects such as honeybees. We review here what is known on the effects of sublethal doses of insecticides on the olfactory system of insect pests. PMID:22457653

  10. Low doses of a neonicotinoid insecticide modify pheromone response thresholds of central but not peripheral olfactory neurons in a pest insect

    PubMed Central

    Rabhi, Kaouther K.; Deisig, Nina; Demondion, Elodie; Le Corre, Julie; Robert, Guillaume; Tricoire-Leignel, Hélène; Lucas, Philippe; Gadenne, Christophe; Anton, Sylvia

    2016-01-01

    Insect pest management relies mainly on neurotoxic insecticides, including neonicotinoids, leaving residues in the environment. There is now evidence that low doses of insecticides can have positive effects on pest insects by enhancing various life traits. Because pest insects often rely on sex pheromones for reproduction, and olfactory synaptic transmission is cholinergic, neonicotinoid residues could modify chemical communication. We recently showed that treatments with different sublethal doses of clothianidin could either enhance or decrease behavioural sex pheromone responses in the male moth, Agrotis ipsilon. We investigated now effects of the behaviourally active clothianidin doses on the sensitivity of the peripheral and central olfactory system. We show with extracellular recordings that both tested clothianidin doses do not influence pheromone responses in olfactory receptor neurons. Similarly, in vivo optical imaging does not reveal any changes in glomerular response intensities to the sex pheromone after clothianidin treatments. The sensitivity of intracellularly recorded antennal lobe output neurons, however, is upregulated by a lethal dose 20 times and downregulated by a dose 10 times lower than the lethal dose 0. This correlates with the changes of behavioural responses after clothianidin treatment and suggests the antennal lobe as neural substrate involved in clothianidin-induced behavioural changes. PMID:26842577

  11. 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

  12. Olfactory biosensor for insect semiochemicals analysis by impedance sensing of odorant-binding proteins on interdigitated electrodes.

    PubMed

    Lu, Yanli; Yao, Yao; Zhang, Qian; Zhang, Diming; Zhuang, Shulin; Li, Hongliang; Liu, Qingjun

    2015-05-15

    Insects can sensitively and selectively detect thousands of semiochemicals at very low concentrations by their remarkable olfactory systems. As one of the most important olfactory proteins, odorant-binding proteins (OBPs) from insects are the most promising candidates for fabricating biosensors to detect biochemical molecules in the chemical ecology as well as for other biotechnological applications. In this study, we designed an olfactory biosensor by immobilizing OBPs from oriental fruit fly on interdigitated electrodes to detect semiochemicals. After successfully separated and purified, OBPs were immobilized by the special designed polyethylene glycol (PEG), SH-PEG-COOH, to produce a robust sensing membrane. Based on electrochemical sensing, interactions between OBPs and different semiochemicals emitted from host plants of the insect, such as the isoamyl acetate, β-ionone, and benzaldehyde, could be sensitively detected. With related amino acid residues in the hydrophobic cavities distinguished, the interaction forces between semiochemicals and OBPs were analyzed by molecular docking. Integrated biological olfaction proteins of insects, OBPs based biosensors could not only advance the progress in the understanding of chemical communication systems of insects, but also show promising potentials for biosensing applications in many fields. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Early olfactory experience modifies neural activity in the antennal lobe of a social insect at the adult stage.

    PubMed

    Arenas, A; Giurfa, M; Farina, W M; Sandoz, J C

    2009-10-01

    In the antennal lobe (AL), the first olfactory centre of the insect brain, odorants are represented as spatiotemporal patterns of glomerular activity. Whether and how such patterns are modified in the long term after precocious olfactory experiences (i.e. in the first days of adulthood) remains unknown. To address this question, we used in vivo optical imaging of calcium activity in the antennal lobe of 17-day-old honeybees which either experienced an odorant associated with sucrose solution 5-8 days after emergence or were left untreated. In both cases, we imaged neural responses to the learned odor and to three novel odors varying in functional group and carbon-chain length. Two different odor concentrations were used. We also measured behavioral responses of 17-day-old honeybees, treated and untreated, to these stimuli. We show that precocious olfactory experience increased general odor-induced activity and the number of activated glomeruli in the adult AL, but also affected qualitative odor representations, which appeared shifted in the neural space of treated animals relative to control animals. Such effects were not limited to the experienced odor, but were generalized to other perceptually similar odors. A similar trend was found in behavioral experiments, in which increased responses to the learned odor extended to perceptually similar odors in treated bees. Our results show that early olfactory experiences have long-lasting effects, reflected in behavioral responses to odorants and concomitant neural activity in the adult olfactory system.

  14. Using an Insect Mushroom Body Circuit to Encode Route Memory in Complex Natural Environments

    PubMed Central

    Mangan, Michael; Lagogiannis, Konstantinos; Webb, Barbara

    2016-01-01

    Ants, like many other animals, use visual memory to follow extended routes through complex environments, but it is unknown how their small brains implement this capability. The mushroom body neuropils have been identified as a crucial memory circuit in the insect brain, but their function has mostly been explored for simple olfactory association tasks. We show that a spiking neural model of this circuit originally developed to describe fruitfly (Drosophila melanogaster) olfactory association, can also account for the ability of desert ants (Cataglyphis velox) to rapidly learn visual routes through complex natural environments. We further demonstrate that abstracting the key computational principles of this circuit, which include one-shot learning of sparse codes, enables the theoretical storage capacity of the ant mushroom body to be estimated at hundreds of independent images. PMID:26866692

  15. Using an Insect Mushroom Body Circuit to Encode Route Memory in Complex Natural Environments.

    PubMed

    Ardin, Paul; Peng, Fei; Mangan, Michael; Lagogiannis, Konstantinos; Webb, Barbara

    2016-02-01

    Ants, like many other animals, use visual memory to follow extended routes through complex environments, but it is unknown how their small brains implement this capability. The mushroom body neuropils have been identified as a crucial memory circuit in the insect brain, but their function has mostly been explored for simple olfactory association tasks. We show that a spiking neural model of this circuit originally developed to describe fruitfly (Drosophila melanogaster) olfactory association, can also account for the ability of desert ants (Cataglyphis velox) to rapidly learn visual routes through complex natural environments. We further demonstrate that abstracting the key computational principles of this circuit, which include one-shot learning of sparse codes, enables the theoretical storage capacity of the ant mushroom body to be estimated at hundreds of independent images.

  16. Synaptic inhibition controls transient oscillatory synchronization in a model of the insect olfactory system

    PubMed Central

    Assisi, Collins; Bazhenov, Maxim

    2011-01-01

    In a variety of neuronal systems it has been hypothesized that inhibitory interneurons corral principal neurons into synchronously firing groups that encode sensory information and sub-serve behavior (Buzsáki and Chrobak, 1995; Buzsáki, 2008). This mechanism is particularly relevant to the olfactory system where spatiotemporal patterns of projection neuron (PN) activity act as robust markers of odor attributes (Laurent et al., 1996; Wehr and Laurent, 1996). In the insect antennal lobe (AL), a network of local inhibitory interneurons arborizes extensively throughout the AL (Leitch and Laurent, 1996) providing inhibitory input to the cholinergic PNs. Our theoretical work has attempted to elaborate the exact role of inhibition in the generation of odor specific PN responses (Bazhenov et al., 2001a,b; Assisi et al., 2011). In large-scale AL network models we characterized the inhibitory sub-network by its coloring (Assisi et al., 2011) and showed that it can entrain excitatory PNs to the odor specific patterns of transient synchronization. In this focused review, we further examine the dynamics of entrainment in more detail by simulating simple model networks in various parameter regimes. Our simulations in conjunction with earlier studies point to the key role played by lateral (between inhibitory interneurons) and feedback (from inhibitory interneurons to principal cells) inhibition in the generation of experimentally observed patterns of transient synchrony. PMID:22529800

  17. How Do Insects Help the Environment?

    ERIC Educational Resources Information Center

    Hevel, Gary

    2005-01-01

    There are some 5 to 30 million insect species estimated in the world--and the majority of these have yet to be collected or named by science! Of course, the most well known insects are those that cause disease or compete for human agricultural products, but these insects represent only a small fraction of the world's insect population. In reality,…

  18. Olfactory Cues Used for Wayfinding in Urban Environments by Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Koutsoklenis, Athanasios; Papadopoulos, Konstantinos

    2011-01-01

    This study examined which olfactory cues individuals with visual impairments use most often and determined which of these cues these individuals deemed to be the most important for wayfinding in urban environments. It also investigated the ways in which the individuals use these olfactory cues. (Contains 3 tables.)

  19. Human olfactory receptors: recombinant expression in the baculovirus/Sf9 insect cell system, functional characterization, and odorant identification.

    PubMed

    Matarazzo, Valéry; Ronin, Catherine

    2013-01-01

    Cell surface expression of recombinant olfactory receptors (ORs) is a major limitation in characterizing their functional nature. We have shown that the recombinant expression of a human OR, OR 17-210, in the baculovirus/Sf9 insect cell system allows this protein to be expressed at the cell surface. We used Ca(2+) imaging to demonstrate that recombinant OR 17-210 produces cellular activities upon odorant stimulation with ketones. Furthermore, this expression and functional system has been used to show that the preincubation of Human Odorant Binding Protein 2A decrease the calcium response of OR 17-210 following stimulation by acetophenone and beta ionone.

  20. Evolutionary dynamics of olfactory receptor genes in chordates: interaction between environments and genomic contents

    PubMed Central

    2009-01-01

    Olfaction is essential for the survival of animals. Versatile odour molecules in the environment are received by olfactory receptors (ORs), which form the largest multigene family in vertebrates. Identification of the entire repertories of OR genes using bioinformatics methods from the whole-genome sequences of diverse organisms revealed that the numbers of OR genes vary enormously, ranging from ~1,200 in rats and ~400 in humans to ~150 in zebrafish and ~15 in pufferfish. Most species have a considerable fraction of pseudogenes. Extensive phylogenetic analyses have suggested that the numbers of gene gains and losses are extremely large in the OR gene family, which is a striking example of the birth-and-death evolution. It appears that OR gene repertoires change dynamically, depending on each organism's living environment. For example, higher primates equipped with a well-developed vision system have lost a large number of OR genes. Moreover, two groups of OR genes for detecting airborne odorants greatly expanded after the time of terrestrial adaption in the tetrapod lineage, whereas fishes retain diverse repertoires of genes that were present in aquatic ancestral species. The origin of vertebrate OR genes can be traced back to the common ancestor of all chordate species, but insects, nematodes and echinoderms utilise distinctive families of chemoreceptors, suggesting that chemoreceptor genes have evolved many times independently in animal evolution. PMID:20038498

  1. Insect Development in Altered Gravitational Environment

    NASA Technical Reports Server (NTRS)

    Tischler, Marc E.

    1996-01-01

    When tobacco hornworm (Manduca sexta) larvae burrow underground (25-30 cm) to pupate, they reorient themselves to a relatively horizontal position indicating an ability to sense gravity. To evaluate their sensitivity to gravitational environment during metamorphosis, Manduca (pharate adults) were placed in a vertical (head-up) position. Distinct morphological changes, each one reflecting ensuing phases, were used to follow adult development. Five days after pupation, the vertical group showed accelerated (P less than 0.05) development and were nearly 4 phases ahead (P less than 0.0001) after 10 days. Differences in development in the vertical group were characterized further by increased (7-48%) hemolymph concentrations of 13 amino acids, but a decrease in cys and pro and no change in arg, his, met and val (trp, undetectable). Decreased (36%) turnover of injected H-3 - phenylalanine suggested slower utilization of amino acids contributed, at least partly, to the increased concentrations. Vertically-oriented Manduca also exhibited a greater (20 %, P less than 0.001) protein content in their flight muscles near the end of development. Analysis of hemolymph sugar levels showed a redistribution of sugars from the monosaccharide glucose to the disaccharide trehalose. Since injection of 20-hydroxyecdysone decreased (49%) turnover of H-3- phenylalanine in pharate adults and since ecdysteroids are known to increase flight muscle size and control adult development, these results are consistent with our measuring a greater (+80%, P less than 0.05) ecdysteroid titer in the vertically-oriented insects. These results suggest that gravity environment influences ecdysone output by the pharate adult. When we evaluated hemolymph flow in the head-up and control positions, we found that injected C-14-inulin was distributed somewhat more rapidly in the head-up group irrespective of the sight of injection (head or abdomen) likely because in the head-up position flow of the hemolymph is

  2. A modular, computer-controlled system for olfactory stimulation in the MRI environment.

    PubMed

    Andrieu, Patrice; Bonnans, Vincent; Meneses, Jaime; Millot, Jean-Louis; Moulin, Thierry; Gharbi, Tijani

    2014-03-01

    Although the cerebral networks involved in sensory perception are of general interest in neuroscience, registration of the effects of olfactory stimulation, especially in a magnetic resonance imaging (MRI) environment, presents particular problems and constraints. This article presents details of a reliable and portable system for olfactory stimulation that is modular in design and based on microcontroller technology. It has the following characteristics: (1) It is under software control; (2) the presentation of olfactory stimulation can be synchronized with respiration; (3) it can be manually controlled; and (4) it is fully compatible with an MRI environment. The principle underlying this system is to direct an odor to the subject's nostrils by switching airflow to different odor diffusers. The characteristics of this system were established using (1) ultraviolet (UV) spectroscopy, to measure its response time, and (2) gas chromatography, to measure the repeatability of odor presentation in terms of gas concentration. A response time of 200 ± 25 ms was obtained for the system, and the standard deviations of the gas concentration delivered during stimulation ranged from 1.5% to 22%, depending on the odor, the airflow, and the dilution of the odor used. Since it is portable, controlled by software, and reliable, on the basis of the results we obtained, this system will lend itself to a wide range of applications in olfactory neuroscience.

  3. Long-term memory shapes the primary olfactory center of an insect brain.

    PubMed

    Hourcade, Benoît; Perisse, Emmanuel; Devaud, Jean-Marc; Sandoz, Jean-Christophe

    2009-10-01

    The storage of stable memories is generally considered to rely on changes in the functional properties and/or the synaptic connectivity of neural networks. However, these changes are not easily tractable given the complexity of the learning procedures and brain circuits studied. Such a search can be narrowed down by studying memories of specific stimuli in a given sensory modality and by working on networks with a modular and relatively simple organization. We have therefore focused on associative memories of individual odors and the possible related changes in the honeybee primary olfactory center, the antennal lobe (AL). As this brain structure is organized in well-identified morpho-functional units, the glomeruli, we looked for evidence of structural and functional plasticity in these units in relation with the bees' ability to store long-term memories (LTMs) of specific odors. Restrained bees were trained to form an odor-specific LTM in an appetitive Pavlovian conditioning protocol. The stability and specificity of this memory was tested behaviorally 3 d after conditioning. At that time, we performed both a structural and a functional analysis on a subset of 17 identified glomeruli by measuring glomerular volume under confocal microscopy, and odor-evoked activity, using in vivo calcium imaging. We show that long-term olfactory memory for a given odor is associated with volume increases in a subset of glomeruli. Independent of these structural changes, odor-evoked activity was not modified. Lastly, we show that structural glomerular plasticity can be predicted based on a putative model of interglomerular connections.

  4. Evolving a Neural Olfactorimotor System in Virtual and Real Olfactory Environments

    PubMed Central

    Rhodes, Paul A.; Anderson, Todd O.

    2012-01-01

    To provide a platform to enable the study of simulated olfactory circuitry in context, we have integrated a simulated neural olfactorimotor system with a virtual world which simulates both computational fluid dynamics as well as a robotic agent capable of exploring the simulated plumes. A number of the elements which we developed for this purpose have not, to our knowledge, been previously assembled into an integrated system, including: control of a simulated agent by a neural olfactorimotor system; continuous interaction between the simulated robot and the virtual plume; the inclusion of multiple distinct odorant plumes and background odor; the systematic use of artificial evolution driven by olfactorimotor performance (e.g., time to locate a plume source) to specify parameter values; the incorporation of the realities of an imperfect physical robot using a hybrid model where a physical robot encounters a simulated plume. We close by describing ongoing work toward engineering a high dimensional, reversible, low power electronic olfactory sensor which will allow olfactorimotor neural circuitry evolved in the virtual world to control an autonomous olfactory robot in the physical world. The platform described here is intended to better test theories of olfactory circuit function, as well as provide robust odor source localization in realistic environments. PMID:23112772

  5. Effects of hydroxyurea parallel the effects of radiation in developing olfactory glomeruli in insects

    SciTech Connect

    Oland, L.A.; Tolbert, L.P.

    1988-12-15

    Previous observations have provided evidence that the afferent-axon-induced development of synaptic glomeruli in the antennal lobe of the moth Manduca sexta depends upon an interaction between ingrowing sensory axons and the glial cells of the antennal lobe. In order to differentiate between the roles of glial cells and of afferent axons on the partitioning of the lobe into glomeruli, we have used the antimitotic agent hydroxyurea to produce lobes deficient in glial cells but retaining sensory input. The resulting lobes were analyzed in the light and electron microscopes, and the integrity of their antennal input was evaluated by examining the gross and microscopic structure of the antennae, the number of antennal afferent axons, and electroantennogram responses to odors. Our results with hydroxyurea show that in treated animals with adequate antennal input the degree to which the antennal-lobe neuropil becomes glomerular varies with the number of glial cells remaining in the lobe; when less than approximately one-quarter of the normal glial complement is present, glomeruli do not develop at all. These experiments complement and extend previous experiments in which the number of glial cells was reduced with radiation. The fact that the present results mimic the previous results with radiation strongly suggest that glial cells do mediate the afferent-axon-induced formation of olfactory glomeruli in the moth.

  6. Using multilayer perceptron computation to discover ideal insect olfactory receptor combinations in the mosquito and fruit fly for an efficient electronic nose.

    PubMed

    Bachtiar, Luqman R; Unsworth, Charles P; Newcomb, Richard D

    2015-01-01

    The model organism, Drosophila melanogaster, and the mosquito Anopheles gambiae use 60 and 79 odorant receptors, respectively, to sense their olfactory world. However, a commercial "electronic nose" in the form of an insect olfactory biosensor demands very low numbers of receptors at its front end of detection due to the difficulties of receptor/sensor integration and functionalization. In this letter, we demonstrate how computation via artificial neural networks (ANNs), in the form of multilayer perceptrons (MLPs), can be successfully incorporated as the signal processing back end of the biosensor to drastically reduce the number of receptors to three while still retaining 100% performance of odorant detection to that of a full complement of receptors. In addition, we provide a detailed performance comparison between D. melanogaster and A. gambiae odorant receptors and demonstrate that A. gambiae receptors provide superior olfaction detection performance over D. melanogaster for very low receptor numbers. The results from this study present the possibility of using the computation of MLPs to discover ideal biological olfactory receptors for an olfactory biosensor device to provide maximum classification performance of unknown odorants.

  7. A thousand bites - Insect introductions and late Holocene environments

    NASA Astrophysics Data System (ADS)

    Panagiotakopulu, Eva; Buckland, Paul C.

    2017-01-01

    The impact of insect species directly associated with man-made habitats and human dispersal has been, and remains globally significant. Their early expansion from their original niches into Europe is intrinsically related to discussions of climate change, origins of domesticated plants and animals, the spread of agriculture and infectious diseases. The Holocene fossil records of the dispersal of three storage pest species, Sitophilus granarius, Oryzaephilus surinamensis, and Tribolium castaneum, the housefly, Musca domestica, and the human flea, Pulex irritans from 221 sites have been mapped ranging from the Near East to Europe and from the Neolithic to the post medieval period. The importance of human induced change as a driver for the spread of synanthropic faunas and the potential for the spread of disease during this process are discussed. The results show links between mobility of farming groups and distribution of synanthropic insect species and produce a roadmap for the different cultural periods of the Late Holocene based on dispersal of these synanthropic insects. During the Neolithic, the first wave of insect introductions shows the northern European frontiers of storage of cereals, introduction of domestic animals and pastoralism and exchange. Pest introductions, linked with the itinerary of the Roman army, reached the most northerly parts of the Empire. During the medieval period, the insect records indicate further expansion and changes which parallel the spread of epidemic diseases like Plague. Understanding the timing and the rates of change of synanthropic insects provides key information about the development of the homogenised and highly anthropogenic environments in which we live today.

  8. Decomposition and insect succession on cadavers inside a vehicle environment.

    PubMed

    Voss, Sasha C; Forbes, Shari L; Dadour, Ian R

    2008-01-01

    This study presents differences in rate of decomposition and insect succession between exposed carcasses on the soil surface and those enclosed within a vehicle following carbon monoxide (CO) poisoning. Nine 45-kg pigs were used as models for human decomposition. Six animals were sacrificed by CO gas, half of which were placed within the driver's side of separate enclosed vehicles and half were placed under scavenger-proof cages on the soil surface. A further three animals were sacrificed by captive headbolt and placed under scavenger proof cages on the soil surface. The pattern of insect succession and rate of decomposition were similar between surface carcasses within trials regardless of the mode of death. Progression through the physical stages of decomposition was 3-4 days faster in the enclosed vehicle due to higher temperatures there compared to external ambient temperatures. Patterns of insect succession also differed between the vehicle and surface treatments. Carcass attendance by representatives of the Calliphoridae was delayed within the vehicle environment by 16-18 h, while oviposition was not observed until 24-28 h following death. In contrast, attendance by Calliphoridae at surface carcasses occurred within 1 h of death, and oviposition occurred within 6-8 h of death. Typical patterns of insect succession on the carcasses were also altered. Carcass attendance by representatives of the Coleoptera occurred during the bloat stage of decomposition at surface carcasses but was delayed until the onset of wet decomposition (as defined by carcass deflation and breakage of the skin) within the vehicle environment. This study provides baseline data outlining the decomposition patterns of a carcass enclosed within a vehicle following CO poisoning in Western Australia. Understanding how variations in decomposition situations impact on the rate of decomposition and patterns of insect succession is essential to obtaining an accurate estimate of minimum post

  9. Oscillation and coding in a formal neural network considered as a guide for plausible simulations of the insect olfactory system.

    PubMed

    Horcholle-Bossavit, Ginette; Quenet, Brigitte; Foucart, Olivier

    2007-01-01

    For the analysis of coding mechanisms in the insect olfactory system, a fully connected network of synchronously updated McCulloch and Pitts neurons (MC-P type) was developed [Quenet, B., Horn, D., 2003. The dynamic neural filter: a binary model of spatio-temporal coding. Neural Comput. 15 (2), 309-329]. Considering the update time as an intrinsic clock, this "Dynamic Neural Filter" (DNF), which maps regions of input space into spatio-temporal sequences of neuronal activity, is able to produce exact binary codes extracted from the synchronized activities recorded at the level of projection neurons (PN) in the locust antennal lobe (AL) in response to different odors [Wehr, M., Laurent, G., 1996. Odor encoding by temporal sequences of firing in oscillating neural assemblies. Nature 384, 162-166]. Here, in a first step, we separate the populations of PN and local inhibitory neurons (LN) and use the DNF as a guide for simulations based on biological plausible neurons (Hodgkin-Huxley: H-H type). We show that a parsimonious network of 10 H-H neurons generates action potentials whose timing represents the required codes. In a second step, we construct a new type of DNF in order to study the population dynamics when different delays are taken into account. We find synaptic matrices which lead to both the emergence of robust oscillations and spatio-temporal patterns, using a formal criterion, based on a Normalized Euclidian Distance (NED), in order to measure the use of the temporal dimension as a coding dimension by the DNF. Similarly to biological PN, the activity of excitatory neurons in the model can be both phase-locked to different cycles of oscillations which remind local field potential (LFP), and nevertheless exhibit dynamic behavior complex enough to be the basis of spatio-temporal codes.

  10. Learning the way to blood: first evidence of dual olfactory conditioning in a blood-sucking insect, Rhodnius prolixus. I. Appetitive learning.

    PubMed

    Vinauger, Clément; Buratti, Laura; Lazzari, Claudio R

    2011-09-15

    It has been largely assumed that the individual experience of insects that are disease vectors might not only contribute to animal fitness, but also have an important influence on parasite transmission. Nevertheless, despite the invested efforts in testing the capacity to learn and remember information in blood-sucking insects, only little conclusive information has been obtained to date. Adapting a classical conditioning approach to our haematophagous model, we trained larvae of Rhodnius prolixus to associate L-lactic-acid, an odour perceived by these bugs but behaviourally neutral when presented alone, with food (i.e. positive reinforcement). Naive bugs--those exposed either to a conditioned stimulus (CS, L-lactic acid), unconditioned stimulus (US, heat) and reward (blood) alone or CS, US and reward in the absence of contingency--remained indifferent to the presence of an air stream loaded with L-lactic acid when tested in an olfactometer (random orientation), whereas the groups previously exposed to the contingency CS-US-reward (blood) were significantly attracted by L-lactic-acid. In a companion paper, the opposite, i.e. repellence, was induced in bugs exposed to the contingency of the same odour with a negative reinforcement. This constitutes the first evidence of olfactory conditioning in triatomine bugs, vectors of Chagas disease, and one of the few substantiations available to date of olfactory conditioning in haematophagous insects.

  11. Evolutionary analysis of herbivorous insects in natural and agricultural environments.

    PubMed

    Gassmann, Aaron J; Onstad, David W; Pittendrigh, Barry R

    2009-11-01

    Herbivorous insects offer a remarkable example of the biological diversity that formed the foundation for Darwin's theory of evolution by natural selection. The ability of insects to evolve resistance rapidly to insecticides and host-plant resistance present a continual challenge for pest management. This paper considers the manner in which genetic constraints, host-plant availability and trade-offs affect the evolution of herbivorous insects in natural and agricultural environments, and the extent to which lessons learned from studying natural systems may be applied to improve insect resistance management in agricultural systems. Studies on the genetic architecture of adaptation by herbivores to host plants and to insecticides are reviewed. The genetic basis of resistance is an important component of simulation models that predict the evolution of resistance. These models often assume monogenic resistance, but available data suggest that this assumption may be overly narrow and that modeling of resistance as oligogenic or polygenic may be more appropriate. As omics (e.g. genomics and proteomics) technologies become more accessible, a better understanding of the genetic basis of resistance will be possible. Trade-offs often accompany adaptations by herbivores. Trade-offs arise when the benefit of a trait, such as the ability to feed on a novel host plant or to survive in the presence of an insecticide, is counterbalanced by fitness costs that decrease fitness in the absence of the selective agent. For resistance to insecticides, and resistance to insecticidal transgenic crops in particular, fitness costs may act as an evolutionary constraint and delay or prevent the evolution of resistance. An important observation is that certain ecological factors such as host plants and entomopathogens can magnify fitness costs, which is termed ecological negative cross-resistance. The application of omics technologies may allow for more efficient identification of factors that

  12. Using Single Sensillum Recording to Detect Olfactory Neuron Responses of Bed Bugs to Semiochemicals.

    PubMed

    Liu, Feng; Liu, Nannan

    2016-01-18

    The insect olfactory system plays an important role in detecting semiochemicals in the environment. In particular, the antennal sensilla which house single or multiple neurons inside, are considered to make the major contribution in responding to the chemical stimuli. By directly recording action potential in the olfactory sensillum after exposure to stimuli, single sensillum recording (SSR) technique provides a powerful approach for investigating the neural responses of insects to chemical stimuli. For the bed bug, which is a notorious human parasite, multiple types of olfactory sensillum have been characterized. In this study, we demonstrated neural responses of bed bug olfactory sensilla to two chemical stimuli and the dose-dependent responses to one of them using the SSR method. This approach enables researchers to conduct early screening for individual chemical stimuli on the bed bug olfactory sensilla, which would provide valuable information for the development of new bed bug attractants or repellents and benefits the bed bug control efforts.

  13. Molecular basis of odor detection in insects.

    PubMed

    Benton, Richard

    2009-07-01

    Olfactory systems are evolutionarily ancient, underlying the common requirement for all animals to sense and respond to diverse volatile chemical signals in their environment. Odor detection is mediated by odorant receptors (ORs) that, in most olfactory systems, comprise large families of divergent G protein-coupled receptors. Here, I discuss our and others' recent investigations of ORs in the fruit fly, Drosophila melanogaster, which have revealed insights into the distinct evolutionary origin and molecular function of insect ORs. I also describe a bioinformatics strategy that we developed to identify molecules that function with these insect-specific receptors in odor detection.

  14. Classifying continuous, real-time e-nose sensor data using a bio-inspired spiking network modelled on the insect olfactory system.

    PubMed

    Diamond, A; Schmuker, M; Berna, A Z; Trowell, S; Nowotny, Thomas

    2016-02-18

    In many application domains, conventional e-noses are frequently outperformed in both speed and accuracy by their biological counterparts. Exploring potential bio-inspired improvements, we note a number of neuronal network models have demonstrated some success in classifying static datasets by abstracting the insect olfactory system. However, these designs remain largely unproven in practical settings, where sensor data is real-time, continuous, potentially noisy, lacks a precise onset signal and accurate classification requires the inclusion of temporal aspects into the feature set. This investigation therefore seeks to inform and develop the potential and suitability of biomimetic classifiers for use with typical real-world sensor data. Taking a generic classifier design inspired by the inhibition and competition in the insect antennal lobe, we apply it to identifying 20 individual chemical odours from the timeseries of responses of metal oxide sensors. We show that four out of twelve available sensors and the first 30 s (10%) of the sensors' continuous response are sufficient to deliver 92% accurate classification without access to an odour onset signal. In contrast to previous approaches, once training is complete, sensor signals can be fed continuously into the classifier without requiring discretization. We conclude that for continuous data there may be a conceptual advantage in using spiking networks, in particular where time is an essential component of computation. Classification was achieved in real time using a GPU-accelerated spiking neural network simulator developed in our group.

  15. Learning the way to blood: first evidence of dual olfactory conditioning in a blood-sucking insect, Rhodnius prolixus. II. Aversive learning.

    PubMed

    Vinauger, Clément; Buratti, Laura; Lazzari, Claudio R

    2011-09-15

    After having demonstrated that blood-sucking bugs are able to associate a behaviourally neutral odour (L-lactic acid) with positive reinforcement (i.e. appetitive conditioning) in the first part of this study, we tested whether these insects were also able to associate the same odour with a negative reinforcement (i.e. aversive conditioning). Learned aversion to host odours has been repeatedly suggested as a determinant for the distribution of disease vectors among host populations. Nevertheless, no experimental evidence has been obtained so far. Adapting a classical conditioning approach to our haematophagous model, we trained larvae of Rhodnius prolixus to associate L-lactic acid, an odour perceived by bugs but behaviourally neutral when presented alone, with a mechanical perturbation (i.e. negative reinforcement). Naive bugs and bugs exposed to CS, punishment, or CS and punishment without contingency remained indifferent to the presence of an air stream loaded with L-lactic acid (random orientation on a locomotion compensator), whereas the groups previously exposed to the contingency CS-punishment were significantly repelled by L-lactic acid. In a companion paper, the opposite, i.e. attraction, was induced in bugs exposed to the contingency of the same odour with a positive reinforcement. These constitute the first pieces of evidence of olfactory conditioning in triatomine bugs and the first demonstration that the same host odour can be used by insects that are disease vectors to learn to recognize either a host to feed on or a potentially defensive one. The orientation mechanism during repulsion is also discussed in light of our results.

  16. Reductive Evolution of Bacterial Genome in Insect Gut Environment

    PubMed Central

    Nikoh, Naruo; Hosokawa, Takahiro; Oshima, Kenshiro; Hattori, Masahira; Fukatsu, Takema

    2011-01-01

    Obligate endocellular symbiotic bacteria of insects and other organisms generally exhibit drastic genome reduction. Recently, it was shown that symbiotic gut bacteria of some stinkbugs also have remarkably reduced genomes. Here, we report the complete genome sequence of such a gut bacterium Ishikawaella capsulata of the plataspid stinkbug Megacopta punctatissima. Gene repertoire and evolutionary patterns, including AT richness and elevated evolutionary rate, of the 745,590 bp genome were strikingly similar to those of obligate γ-proteobacterial endocellular insect symbionts like Buchnera in aphids and Wigglesworthia in tsetse flies. Ishikawaella was suggested to supply essential amino acids for the plant-sucking stinkbug as Buchnera does for the host aphid. Although Buchnera is phylogenetically closer to Wigglesworthia than to Ishikawaella, in terms of gene repertoire Buchnera was similar to Ishikawaella rather than to Wigglesworthia, providing a possible case of genome-level convergence of gene content. Meanwhile, several notable differences were identified between the genomes of Ishikawaella and Buchnera, including retention of TCA cycle genes and lack of flagellum-related genes in Ishikawaella, which may reflect their adaptation to distinct symbiotic habitats. Unexpectedly, Ishikawaella retained fewer genes related to cell wall synthesis and lipid metabolism than many endocellular insect symbionts. The plasmid of Ishikawaella encoded genes for arginine metabolism and oxalate detoxification, suggesting the possibility of additional Ishikawaella roles similar to those of human gut bacteria. Our data highlight strikingly similar evolutionary patterns that are shared between the extracellular and endocellular insect symbiont genomes. PMID:21737395

  17. 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

  18. Lack of TRPM5-Expressing Microvillous Cells in Mouse Main Olfactory Epithelium Leads to Impaired Odor-Evoked Responses and Olfactory-Guided Behavior in a Challenging Chemical Environment

    PubMed Central

    Lemons, Kayla; Aoudé, Imad; Ogura, Tatsuya; Mbonu, Kenechukwu; Matsumoto, Ichiro; Arakawa, Hiroyuki

    2017-01-01

    The mammalian main olfactory epithelium (MOE) modifies its activities in response to changes in the chemical environment. This process is essential for maintaining the functions of the olfactory system and the upper airway. However, mechanisms involved in this functional maintenance, especially those occurring via paracrine regulatory pathways within the multicellular MOE, are poorly understood. Previously, a population of non-neuronal, transient receptor potential M5-expressing microvillous cells (TRPM5-MCs) was identified in the MOE, and the initial characterization of these cells showed that they are cholinergic and responsive to various xenobiotics including odorants at high concentrations. Here, we investigated the role of TRPM5-MCs in maintaining olfactory function using transcription factor Skn-1a knockout (Skn-1a-/-) mice, which lack TRPM5-MCs in the MOE. Under our standard housing conditions, Skn-1a-/- mice do not differ significantly from control mice in odor-evoked electro-olfactogram (EOG) responses and olfactory-guided behaviors, including finding buried food and preference reactions to socially and sexually relevant odors. However, after a 2-wk exposure to high-concentration odor chemicals and chitin powder, Skn-1a-/- mice exhibited a significant reduction in their odor and pheromone-evoked EOG responses. Consequently, their olfactory-guided behaviors were impaired compared with vehicle-exposed Skn-1a-/- mice. Conversely, the chemical exposure did not induce significant changes in the EOG responses and olfactory behaviors of control mice. Therefore, our physiological and behavioral results indicate that TRPM5-MCs play a protective role in maintaining the olfactory function of the MOE. PMID:28612045

  19. 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

  20. Preliminary data on carrion insects in urban (indoor and outdoor) and periurban environments in central Spain.

    PubMed

    Baz, Arturo; Botías, Cristina; Martín-Vega, Daniel; Cifrián, Blanca; Díaz-Aranda, Luisa M

    2015-03-01

    Although most cases involving entomological evidence occur in urban environments and under indoor conditions, there is a lack of studies determining the insect fauna of forensic importance in those environments. In the current paper we provide the first data on the composition of the forensically important insect species occurring in periurban and both indoor and outdoor urban environments in central Spain. Insects were collected fortnightly by means of carrion-baited traps, uninterruptedly during one year. Most species and individuals were collected in the periurban site, whereas the indoor urban site showed the lowest number of species and captures. Moreover, the composition of species differed among environments and seasons. A few species occurred under both indoor and outdoor conditions, including the blowfly Calliphora vicina and some Sarcophagidae species. These preliminary results suggest interesting differences in the insect composition between environments and conditions which may be of forensic importance, and represent a first step to further research into the application of insects to forensic investigations in urban environments of central Spain.

  1. Dimorphic olfactory lobes in the arthropoda.

    PubMed

    Strausfeld, Nicholas; Reisenman, Carolina E

    2009-07-01

    Specialized olfactory lobe glomeruli relating to sexual or caste differences have been observed in at least five orders of insects, suggesting an early appearance of this trait in insect evolution. Dimorphism is not limited to nocturnal species, but occurs even in insects that are known to use vision for courtship. Other than a single description, there is no evidence for similar structures occurring in the Crustacea, suggesting that the evolution of dimorphic olfactory systems may typify terrestrial arthropods.

  2. Plasticity in Insect Olfaction: To Smell or Not to Smell?

    PubMed

    Gadenne, Christophe; Barrozo, Romina B; Anton, Sylvia

    2016-01-01

    In insects, olfaction plays a crucial role in many behavioral contexts, such as locating food, sexual partners, and oviposition sites. To successfully perform such behaviors, insects must respond to chemical stimuli at the right moment. Insects modulate their olfactory system according to their physiological state upon interaction with their environment. Here, we review the plasticity of behavioral responses to different odor types according to age, feeding state, circadian rhythm, and mating status. We also summarize what is known about the underlying neural and endocrinological mechanisms, from peripheral detection to central nervous integration, and cover neuromodulation from the molecular to the behavioral level. We describe forms of olfactory plasticity that have contributed to the evolutionary success of insects and have provided them with remarkable tools to adapt to their ever-changing environment.

  3. Reduced odor responses from antennal neurons of G(q)alpha, phospholipase Cbeta, and rdgA mutants in Drosophila support a role for a phospholipid intermediate in insect olfactory transduction.

    PubMed

    Kain, Pinky; Chakraborty, Tuhin Subra; Sundaram, Susinder; Siddiqi, Obaid; Rodrigues, Veronica; Hasan, Gaiti

    2008-04-30

    Mechanisms by which G-protein-coupled odorant receptors transduce information in insects still need elucidation. We show that mutations in the Drosophila gene for G(q)alpha (dgq) significantly reduce both the amplitude of the field potentials recorded from the whole antenna in responses to odorants as well as the frequency of evoked responses of individual sensory neurons. This requirement for G(q)alpha is for adult function and not during antennal development. Conversely, brief expression of a dominant-active form of G(q)alpha in adults leads to enhanced odor responses. To understand signaling downstream of G(q)alpha in olfactory sensory neurons, genetic interactions of dgq were tested with mutants in genes known to affect phospholipid signaling. dgq mutant phenotypes were further enhanced by mutants in a PLCbeta (phospholipase Cbeta) gene, plc21C. Interestingly although, the olfactory phenotype of mutant alleles of diacylglycerol kinase (rdgA) was rescued by dgq mutant alleles. Our results suggest that G(q)alpha-mediated olfactory transduction in Drosophila requires a phospholipid second messenger the levels of which are regulated by a cycle of phosphatidylinositol 1,4-bisphosphate breakdown and regeneration.

  4. Insects Represent a Link between Food Animal Farms and the Urban Environment for Antibiotic Resistance Traits

    PubMed Central

    Ghosh, Anuradha

    2014-01-01

    Antibiotic-resistant bacterial infections result in higher patient mortality rates, prolonged hospitalizations, and increased health care costs. Extensive use of antibiotics as growth promoters in the animal industry represents great pressure for evolution and selection of antibiotic-resistant bacteria on farms. Despite growing evidence showing that antibiotic use and bacterial resistance in food animals correlate with resistance in human pathogens, the proof for direct transmission of antibiotic resistance is difficult to provide. In this review, we make a case that insects commonly associated with food animals likely represent a direct and important link between animal farms and urban communities for antibiotic resistance traits. Houseflies and cockroaches have been shown to carry multidrug-resistant clonal lineages of bacteria identical to those found in animal manure. Furthermore, several studies have demonstrated proliferation of bacteria and horizontal transfer of resistance genes in the insect digestive tract as well as transmission of resistant bacteria by insects to new substrates. We propose that insect management should be an integral part of pre- and postharvest food safety strategies to minimize spread of zoonotic pathogens and antibiotic resistance traits from animal farms. Furthermore, the insect link between the agricultural and urban environment presents an additional argument for adopting prudent use of antibiotics in the food animal industry. PMID:24705326

  5. Insects represent a link between food animal farms and the urban environment for antibiotic resistance traits.

    PubMed

    Zurek, Ludek; Ghosh, Anuradha

    2014-06-01

    Antibiotic-resistant bacterial infections result in higher patient mortality rates, prolonged hospitalizations, and increased health care costs. Extensive use of antibiotics as growth promoters in the animal industry represents great pressure for evolution and selection of antibiotic-resistant bacteria on farms. Despite growing evidence showing that antibiotic use and bacterial resistance in food animals correlate with resistance in human pathogens, the proof for direct transmission of antibiotic resistance is difficult to provide. In this review, we make a case that insects commonly associated with food animals likely represent a direct and important link between animal farms and urban communities for antibiotic resistance traits. Houseflies and cockroaches have been shown to carry multidrug-resistant clonal lineages of bacteria identical to those found in animal manure. Furthermore, several studies have demonstrated proliferation of bacteria and horizontal transfer of resistance genes in the insect digestive tract as well as transmission of resistant bacteria by insects to new substrates. We propose that insect management should be an integral part of pre- and postharvest food safety strategies to minimize spread of zoonotic pathogens and antibiotic resistance traits from animal farms. Furthermore, the insect link between the agricultural and urban environment presents an additional argument for adopting prudent use of antibiotics in the food animal industry.

  6. The complete swine olfactory subgenome: expansion of the olfactory gene repertoire in the pig genome.

    PubMed

    Nguyen, Dinh Truong; Lee, Kyooyeol; Choi, Hojun; Choi, Min-kyeung; Le, Minh Thong; Song, Ning; Kim, Jin-Hoi; Seo, Han Geuk; Oh, Jae-Wook; Lee, Kyungtae; Kim, Tae-Hun; Park, Chankyu

    2012-11-15

    Insects and animals can recognize surrounding environments by detecting thousands of chemical odorants. Olfaction is a complicated process that begins in the olfactory epithelium with the specific binding of volatile odorant molecules to dedicated olfactory receptors (ORs). OR proteins are encoded by the largest gene superfamily in the mammalian genome. We report here the whole genome analysis of the olfactory receptor genes of S. scrofa using conserved OR gene specific motifs and known OR protein sequences from diverse species. We identified 1,301 OR related sequences from the S. scrofa genome assembly, Sscrofa10.2, including 1,113 functional OR genes and 188 pseudogenes. OR genes were located in 46 different regions on 16 pig chromosomes. We classified the ORs into 17 families, three Class I and 14 Class II families, and further grouped them into 349 subfamilies. We also identified inter- and intra-chromosomal duplications of OR genes residing on 11 chromosomes. A significant number of pig OR genes (n = 212) showed less than 60% amino acid sequence similarity to known OR genes of other species. As the genome assembly Sscrofa10.2 covers 99.9% of the pig genome, our analysis represents an almost complete OR gene repertoire from an individual pig genome. We show that S. scrofa has one of the largest OR repertoires, suggesting an expansion of OR genes in the swine genome. A significant number of unique OR genes in the pig genome may suggest the presence of swine specific olfactory stimulation.

  7. Parallel processing in the honeybee olfactory pathway: structure, function, and evolution.

    PubMed

    Rössler, Wolfgang; Brill, Martin F

    2013-11-01

    Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to "what-" and "where" subsystems in visual pathways, this suggests two parallel olfactory subsystems providing "what-" (quality) and "when" (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.

  8. Host plant resistance to insects: an eco-friendly approach for pest management and environment conservation.

    PubMed

    Sharma, H C; Ortiz, Rodomiro

    2002-04-01

    Host plant resistance (HPR) to insects is an effective, economical, and environment friendly method of pest control. The most attractive feature of HPR is that farmers virtually do not need any skill in application techniques, and there is no cash investment by the resource poor farmers. Considerable progress has been made in identification and development of crop cultivars with resistance to the major pests in different crops. There is a need to transfer resistance genes into high-yielding cultivars with adaptation to different agro-ecosystems. Resistance to insects should form one of the criteria to release varieties and hybrids for cultivation by the farmers. Genes from the wild relatives of crops, and novel genes, such as those from Bacillus thuringiensis can also be deployed in different crops to make HPR an effective weapon to minimize the losses due to insect pests. HPR will not only cause a major reduction in pesticide use and slowdown the rate of development of resistance to insecticides in insect populations, but also lead to increased activity of beneficial organisms and reduction in pesticide residues in food and food products.

  9. Bacillus thuringiensis (Bt) transgenic crop: an environment friendly insect-pest management strategy.

    PubMed

    Kumar, Suresh; Chandra, Amaresh; Pandey, K C

    2008-09-01

    Introduction of DDT (dichloro-diphenyl-trichloroethane) and following move towards indiscriminate use of synthetic chemical insecticides led to the contamination of water and food sources, poisoning of non-target beneficial insects and development of insect-pests resistant to the chemical insecticides. Increased public concems about the adverse environmental effects of indiscriminate use of chemical insecticides prompted search of altemative methods for insect-pest control. One of the promising alternatives has been the use of biological control agents. There is well-documented history of safe application of Bt (B. thuringiensis, a gram positive soil bacterium) as effective biopesticides and a number of reports of expression of delta-endotoxin gene(s) in crop plants are available. Only a few insecticidal sprays are required on Bt transgenic crops, which not only save cost and time, but also reduce health risks. Insects exhibit remarkable ability to develop resistance to different insecticidal compounds, which raises concern about the unsystematic use of Bt transgenic technology also. Though resistance to Bt products among insect species under field conditions has been rare, laboratory studies show that insects are capable of developing high levels of resistance to one ormore Cry proteins. Now it is generally agreed that 'high-dose/refuge strategy' is the most promising and practical approach to prolong the effectiveness of Bt toxins. Although manybiosafety concerns, ethical and moral issues exist, area under Bt transgenic crops is rapidly increasing and they are cultivated on more than 32 million hectares world over Even after reservation of European Union (EU) for acceptance of geneticaly modified (GM) crops, 6 out of 25 countries have already adopted Bt crops and many otherindustrial countries will adopt Bt transgenic crops in near future. While the modem biotechnology has been recognized to have a great potential for the promotion of human well-being, adoption

  10. Signal interactions and interference in insect choruses: singing and listening in the social environment.

    PubMed

    Greenfield, Michael D

    2015-01-01

    Acoustic insects usually sing amidst conspecifics, thereby creating a social environment-the chorus-in which individuals communicate, find mates, and avoid predation. A temporal structure may arise in a chorus because of competitive and cooperative factors that favor certain signal interactions between neighbors. This temporal structure can generate significant acoustic interference among singers that pose problems for communication, mate finding, and predator detection. Acoustic insects can reduce interference by means of selective attention to only their nearest neighbors and by alternating calls with neighbors. Alternatively, they may synchronize, allowing them to preserve call rhythm and also to listen for predators during the silent intervals between calls. Moreover, males singing in choruses may benefit from reduced per capita predation risk as well as enhanced vigilance. They may also enjoy greater per capita attractiveness to females, particularly in the case of synchronous choruses. In many cases, however, the overall temporal structure of the chorus is only an emergent property of simple, pairwise interactions between neighbors. Nonetheless, the chorus that emerges can impose significant selection pressure on the singing of those individual males. Thus, feedback loops may occur and potentially influence traits at both individual and group levels in a chorus.

  11. Neuromodulation of olfactory sensitivity in the peripheral olfactory organs of the American cockroach, Periplaneta americana.

    PubMed

    Jung, Je Won; Kim, Jin-Hee; Pfeiffer, Rita; Ahn, Young-Joon; Page, Terry L; Kwon, Hyung Wook

    2013-01-01

    Olfactory sensitivity exhibits daily fluctuations. Several studies have suggested that the olfactory system in insects is modulated by both biogenic amines and neuropeptides. However, molecular and neural mechanisms underlying olfactory modulation in the periphery remain unclear since neuronal circuits regulating olfactory sensitivity have not been identified. Here, we investigated the structure and function of these signaling pathways in the peripheral olfactory system of the American cockroach, Periplaneta americana, utilizing in situ hybridization, qRT-PCR, and electrophysiological approaches. We showed that tachykinin was co-localized with the octopamine receptor in antennal neurons located near the antennal nerves. In addition, the tachykinin receptor was found to be expressed in most of the olfactory receptor neurons in antennae. Functionally, the effects of direct injection of tachykinin peptides, dsRNAs of tachykinin, tachykinin receptors, and octopamine receptors provided further support for the view that both octopamine and tachykinin modulate olfactory sensitivity. Taken together, these findings demonstrated that octopamine and tachykinin in antennal neurons are olfactory regulators in the periphery. We propose here the hypothesis that octopamine released from neurons in the brain regulates the release of tachykinin from the octopamine receptor neurons in antennae, which in turn modulates the olfactory sensitivity of olfactory receptor neurons, which house tachykinin receptors.

  12. An autonomous robot inspired by insect neurophysiology pursues moving features in natural environments

    NASA Astrophysics Data System (ADS)

    Bagheri, Zahra M.; Cazzolato, Benjamin S.; Grainger, Steven; O'Carroll, David C.; Wiederman, Steven D.

    2017-08-01

    Objective. Many computer vision and robotic applications require the implementation of robust and efficient target-tracking algorithms on a moving platform. However, deployment of a real-time system is challenging, even with the computational power of modern hardware. Lightweight and low-powered flying insects, such as dragonflies, track prey or conspecifics within cluttered natural environments, illustrating an efficient biological solution to the target-tracking problem. Approach. We used our recent recordings from ‘small target motion detector’ neurons in the dragonfly brain to inspire the development of a closed-loop target detection and tracking algorithm. This model exploits facilitation, a slow build-up of response to targets which move along long, continuous trajectories, as seen in our electrophysiological data. To test performance in real-world conditions, we implemented this model on a robotic platform that uses active pursuit strategies based on insect behaviour. Main results. Our robot performs robustly in closed-loop pursuit of targets, despite a range of challenging conditions used in our experiments; low contrast targets, heavily cluttered environments and the presence of distracters. We show that the facilitation stage boosts responses to targets moving along continuous trajectories, improving contrast sensitivity and detection of small moving targets against textured backgrounds. Moreover, the temporal properties of facilitation play a useful role in handling vibration of the robotic platform. We also show that the adoption of feed-forward models which predict the sensory consequences of self-movement can significantly improve target detection during saccadic movements. Significance. Our results provide insight into the neuronal mechanisms that underlie biological target detection and selection (from a moving platform), as well as highlight the effectiveness of our bio-inspired algorithm in an artificial visual system.

  13. Incredible Insects.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1989-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. Contents are organized into the following sections: (1) "What Makes an Insect an Insect?,"…

  14. Insect Development, Thermal Plasticity and Fitness Implications in Changing, Seasonal Environments.

    PubMed

    Buckley, Lauren B; Arakaki, Andrew J; Cannistra, Anthony F; Kharouba, Heather M; Kingsolver, Joel G

    2017-06-28

    Historical data show that recent climate change has caused advances in seasonal timing (phenology) in many animals and plants, particularly in temperate and higher latitude regions. The population and fitness consequences of these phenological shifts for insects and other ectotherms have been heterogeneous: warming can increase development rates and the number of generations per year (increasing fitness), but can also lead to seasonal mismatches between animals and their resources and increase exposure to environmental variability (decreasing fitness). Insect populations exhibit local adaptation in their developmental responses to temperature, including lower developmental thresholds and the thermal requirements to complete development, but climate change can potentially disrupt seasonal timing of juvenile and adult stages and alter population fitness. We investigate these issues using a global dataset describing how insect developmental responds to temperature via two traits: lower temperature thresholds for development (T0) and the cumulative degree-days required to complete development (G). As suggested by previous analyses, T0 decreases and G increases with increasing (absolute) latitude; however, these traits and the relationship between G and latitude varies significantly among taxonomic orders. The mean number of generations per year (a metric of fitness) increases with both decreasing T0 and G, but the effects of these traits on fitness vary strongly with latitude, with stronger selection on both traits at higher (absolute) latitudes. We then use the traits to predict developmental timing and temperatures for multiple generations within seasons and across years (1970-2010). Seasonality drives developmental temperatures to peak mid-season and for generation lengths to decline across seasons, particularly in temperate regions. We predict that climate warming has advanced phenology and increased the number of generations, particularly at high latitudes. The

  15. Environment and Spatial Influences on Aquatic Insect Communities in Cerrado Streams: the Relative Importance of Conductivity, Altitude, and Conservation Areas.

    PubMed

    Godoy, B S; Queiroz, L L; Lodi, S; Oliveira, L G

    2017-04-01

    The aquatic insect community is an important element for stream functionality and diversity, but the effects of altitude and conservation areas on the aquatic insect community have been poorly explored in neotropical ecozone. The lack of studies about the relative importance of space and environment on community structure is another obstacle within aquatic insect ecology, which precludes the inclusion of these studies in more current frameworks, like the metacommunity dynamics. We evaluated the relationship between the aquatic insect community structure at 19 streams in the Brazilian Cerrado and spatial and environmental variables, namely geographical distance among sites, stream altitude, chemical variables, and environmental protection areas. We partitioned the variance explained by spatial and environmental components using a partial redundancy analysis. The environment exhibited a strong spatial structure for abundance and number of genera, increasing these community parameters with elevated water conductivity. Only community composition had a large unexplained portion of variance, with a small portion constrained by environmental (altitude and conductivity) and spatial factors. A relevant point in the result was the streams with high conductivity were located outside of the conservation areas. These results suggest that the relationship between number of genera and abundance with environmental conditions is always associated with spatial configuration of streams. Our study shows that altitude is an important determinant of community structure, as it exerts indirect influences, and electrical conductivity directly determines community composition, and that some national parks may be inefficient in maintaining the diversity of aquatic insects in the Cerrado region.

  16. Autonomous Visual Navigation of an Indoor Environment Using a Parsimonious, Insect Inspired Familiarity Algorithm.

    PubMed

    Gaffin, Douglas D; Brayfield, Brad P

    2016-01-01

    The navigation of bees and ants from hive to food and back has captivated people for more than a century. Recently, the Navigation by Scene Familiarity Hypothesis (NSFH) has been proposed as a parsimonious approach that is congruent with the limited neural elements of these insects' brains. In the NSFH approach, an agent completes an initial training excursion, storing images along the way. To retrace the path, the agent scans the area and compares the current scenes to those previously experienced. By turning and moving to minimize the pixel-by-pixel differences between encountered and stored scenes, the agent is guided along the path without having memorized the sequence. An important premise of the NSFH is that the visual information of the environment is adequate to guide navigation without aliasing. Here we demonstrate that an image landscape of an indoor setting possesses ample navigational information. We produced a visual landscape of our laboratory and part of the adjoining corridor consisting of 2816 panoramic snapshots arranged in a grid at 12.7-cm centers. We show that pixel-by-pixel comparisons of these images yield robust translational and rotational visual information. We also produced a simple algorithm that tracks previously experienced routes within our lab based on an insect-inspired scene familiarity approach and demonstrate that adequate visual information exists for an agent to retrace complex training routes, including those where the path's end is not visible from its origin. We used this landscape to systematically test the interplay of sensor morphology, angles of inspection, and similarity threshold with the recapitulation performance of the agent. Finally, we compared the relative information content and chance of aliasing within our visually rich laboratory landscape to scenes acquired from indoor corridors with more repetitive scenery.

  17. Aquatic insects in a multistress environment: cross-tolerance to salinity and desiccation.

    PubMed

    Pallarés, Susana; Botella-Cruz, María; Arribas, Paula; Millán, Andrés; Velasco, Josefa

    2017-04-01

    Exposing organisms to a particular stressor may enhance tolerance to a subsequent stress, when protective mechanisms against the two stressors are shared. Such cross-tolerance is a common adaptive response in dynamic multivariate environments and often indicates potential co-evolution of stress traits. Many aquatic insects in inland saline waters from Mediterranean-climate regions are sequentially challenged with salinity and desiccation stress. Thus, cross-tolerance to these physiologically similar stressors could have been positively selected in insects of these regions. We used adults of the saline water beetles Enochrus jesusarribasi (Hydrophilidae) and Nebrioporus baeticus (Dytiscidae) to test cross-tolerance responses to desiccation and salinity. In independent laboratory experiments, we evaluated the effects of (i) salinity stress on the subsequent resistance to desiccation and (ii) desiccation stress (rapid and slow dehydration) on the subsequent tolerance to salinity. Survival, water loss and haemolymph osmolality were measured. Exposure to stressful salinity improved water control under subsequent desiccation stress in both species, with a clear cross-tolerance (enhanced performance) in N. baeticus In contrast, general negative effects on performance were found under the inverse stress sequence. The rapid and slow dehydration produced different water loss and haemolymph osmolality dynamics that were reflected in different survival patterns. Our finding of cross-tolerance to salinity and desiccation in ecologically similar species from distant lineages, together with parallel responses between salinity and thermal stress previously found in several aquatic taxa, highlights the central role of adaption to salinity and co-occurring stressors in arid inland waters, having important implications for the species' persistence under climate change.

  18. Living with genome instability: the adaptation of phytoplasmas todiverse environments of their insect and plant hosts

    SciTech Connect

    Bai, Xiaodong; Zhang, Jianhua; Ewing, Adam; Miller, Sally A.; Radek, Agnes; Shevchenko, Dimitriy; Tsukerman, Kiryl; Walunas, Theresa; Lapidus, Alla; Campbell, John W.; Hogenhout Saskia A.

    2006-02-17

    Phytoplasmas (Candidatus Phytoplasma, Class Mollicutes) cause disease in hundreds of economically important plants, and are obligately transmitted by sap-feeding insects of the order Hemiptera, mainly leafhoppers and psyllids. The 706,569-bp chromosome and four plasmids of aster yellows phytoplasma strain witches broom (AY-WB) were sequenced and compared to the onion yellows phytoplasma strain M (OY-M) genome. The phytoplasmas have small repeat-rich genomes. The repeated DNAs are organized into large clusters, potential mobile units (PMUs), which contain tra5 insertion sequences (ISs), and specialized sigma factors and membrane proteins. So far, PMUs are unique to phytoplasmas. Compared to mycoplasmas, phytoplasmas lack several recombination and DNA modification functions, and therefore phytoplasmas probably use different mechanisms of recombination, likely involving PMUs, for the creation of variability, allowing phytoplasmas to adjust to the diverse environments of plants and insects. The irregular GC skews and presence of ISs and large repeated sequences in the AY-WB and OY-M genomes are indicative of high genomic plasticity. Nevertheless, segments of {approx}250 kb, located between genes lplA and glnQ are syntenic between the two phytoplasmas, contain the majority of the metabolic genes and no ISs. AY-WB is further along in the reductive evolution process than OY-M. The AY-WB genome is {approx}154 kb smaller than the OY-M genome, primarily as a result of fewer multicopy sequences, including PMUs. Further, AY-WB lacks genes that are truncated and are part of incomplete pathways in OY-M. This is the first comparative phytoplasma genome analysis and report of the existence of PMUs in phytoplasma genomes.

  19. Innate olfactory preferences in dung beetles.

    PubMed

    Dormont, Laurent; Jay-Robert, Pierre; Bessière, Jean-Marie; Rapior, Sylvie; Lumaret, Jean-Pierre

    2010-09-15

    The effects of insect larval diet on adult olfactory responses to host-plant or food volatiles are still debated. The induction of adult host preferences has been studied in insects with diverse ecologies, including parasitoids, flower-visitors and phytophagous species. We investigated this question for the first time in a coprophagous insect species. Larvae of the French scarab dung beetle Agrilinus constans were reared on four different artificial substrates containing dung from cattle, horse, sheep or wild boar, and responses of imagos to dung volatiles were then behaviourally tested in an olfactometer. We also reported the first analysis of the composition of different mammal dung volatiles. We showed that adult beetles were more attracted to cattle and sheep dung odours, and that larval feeding experience had no effect on the adult olfactory responses to dung volatiles. A second experiment showed that the presence of other insects inside the dung resource affects the process of dung selection by adults. We identified 64 chemical compounds from dung emissions, and showed that dung volatiles clearly differed among different mammal species, allowing olfactory discrimination by dung beetles. Our results suggest that resource selection in coprophagous insects may be based on innate olfactory preferences. Further experiments should examine whether Agrilinus adults can learn new dung odours, and whether larval diet may influence the behaviour of adults in other coprophagous species.

  20. Ability of essential oil candles to repel biting insects in high and low biting pressure environments.

    PubMed

    Müller, Günter C; Junnila, Amy; Kravchenko, Vasiliy D; Revay, Edita E; Butler, Jerry; Orlova, Olga B; Weiss, Robert W; Schlein, Yosef

    2008-03-01

    The first goal of this study was to compare the degree of personal protection against biting insects provided by geraniol, linalool, and citronella candle (5%) vapors outdoors, where such products are commonly used. At a distance of 1.0 m, citronella candles reduced the number of female mosquitoes caught in Centers for Disease Control and Prevention traps by 35.4% and sand flies by 15.4%, linalool candles reduced female mosquitoes by 64.9% and sand flies by 48.5%, while geraniol candles reduced female mosquitoes by 81.5% and sand flies by 69.8%. By increasing the distance to 2 m and 3 m, the repellency dropped significantly. The second goal was to compare the degree of personal protection provided by the best performing candle, geraniol, under conditions of high and low biting pressure. The introduction of geraniol candles to protect volunteers in a high biting pressure environment reduced the mosquito pressure by an average of 56% and the sand fly pressure by 62% over a distance of 1.0 m. In the low biting pressure environment, geraniol reduced the mosquito pressure by an average of 62%. No sand flies were present at this site.

  1. 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

  2. Olfactory coding in the honeybee lateral horn.

    PubMed

    Roussel, Edith; Carcaud, Julie; Combe, Maud; Giurfa, Martin; Sandoz, Jean-Christophe

    2014-03-03

    Olfactory systems dynamically encode odor information in the nervous system. Insects constitute a well-established model for the study of the neural processes underlying olfactory perception. In insects, odors are detected by sensory neurons located in the antennae, whose axons project to a primary processing center, the antennal lobe. There, the olfactory message is reshaped and further conveyed to higher-order centers, the mushroom bodies and the lateral horn. Previous work has intensively analyzed the principles of olfactory processing in the antennal lobe and in the mushroom bodies. However, how the lateral horn participates in olfactory coding remains comparatively more enigmatic. We studied odor representation at the input to the lateral horn of the honeybee, a social insect that relies on both floral odors for foraging and pheromones for social communication. Using in vivo calcium imaging, we show consistent neural activity in the honeybee lateral horn upon stimulation with both floral volatiles and social pheromones. Recordings reveal odor-specific maps in this brain region as stimulations with the same odorant elicit more similar spatial activity patterns than stimulations with different odorants. Odor-similarity relationships are mostly conserved between antennal lobe and lateral horn, so that odor maps recorded in the lateral horn allow predicting bees' behavioral responses to floral odorants. In addition, a clear segregation of odorants based on pheromone type is found in both structures. The lateral horn thus contains an odor-specific map with distinct representations for the different bee pheromones, a prerequisite for eliciting specific behaviors.

  3. Patch-clamping arthropod olfactory receptor neurons to study mechanisms of olfactory transduction.

    PubMed

    Hatt, H; Ache, B W

    1996-10-21

    The olfactory organ of arthropods such as lobsters and insects consists of an array of hair-like sensilla located on the antenna. Each sensillum contains from two to several hundred primary olfactory receptor neurons. The receptor neurons can be patch-clamped in three different types of preparations: intact cells in situ, cultured cells and outer dendrites. These preparations permit using a wide range of experimental strategies to study mechanisms of olfactory transduction. The ability to integrate data from three complementary preparations is a particular advantage of using arthropod models to understand how odor information is encoded by the primary receptor cell in olfaction.

  4. A Review of Chemosensation and Related Behavior in Aquatic Insects

    PubMed Central

    Crespo, José G.

    2011-01-01

    Insects that are secondarily adapted to aquatic environments are able to sense odors from a diverse array of sources. The antenna of these insects, as in all insects, is the main chemosensory structure and its input to the brain allows for integration of sensory information that ultimately ends in behavioral responses. Only a fraction of the aquatic insect orders have been studied with respect to their sensory biology and most of the work has centered either on the description of the different types of sensilla, or on the behavior of the insect as a whole. In this paper, the literature is exhaustively reviewed and ways in which antennal morphology, brain structure, and associated behavior can advance better understanding of the neurobiology involved in processing of chemosensory information are discussed. Moreover, the importance of studying such group of insects is stated, and at the same time it is shown that many interesting questions regarding olfactory processing can be addressed by looking into the changes that aquatic insects undergo when leaving their aquatic environment. PMID:21864156

  5. A review of chemosensation and related behavior in aquatic insects.

    PubMed

    Crespo, José G

    2011-01-01

    Insects that are secondarily adapted to aquatic environments are able to sense odors from a diverse array of sources. The antenna of these insects, as in all insects, is the main chemosensory structure and its input to the brain allows for integration of sensory information that ultimately ends in behavioral responses. Only a fraction of the aquatic insect orders have been studied with respect to their sensory biology and most of the work has centered either on the description of the different types of sensilla, or on the behavior of the insect as a whole. In this paper, the literature is exhaustively reviewed and ways in which antennal morphology, brain structure, and associated behavior can advance better understanding of the neurobiology involved in processing of chemosensory information are discussed. Moreover, the importance of studying such group of insects is stated, and at the same time it is shown that many interesting questions regarding olfactory processing can be addressed by looking into the changes that aquatic insects undergo when leaving their aquatic environment.

  6. Selectivity of odorant receptors in insects

    USDA-ARS?s Scientific Manuscript database

    Insect olfactory receptors (ORs) detect chemical signals, shape neuronal physiology and regulate behavior. Although ORs have been categorized as generalists and specialists based on their ligand spectrum, both electrophysiological studies and recent pharmacological investigations show that ORs spec...

  7. Olfactory neuroblastoma

    SciTech Connect

    O'Connor, T.A.; McLean, P.; Juillard, G.J.; Parker, R.G.

    1989-06-15

    Fifteen patients with olfactory neuroblastoma were treated during the 17-year period of 1969 to 1986. Data was analyzed with respect to age at presentation, sex, presenting signs and symptoms, stage, and results of treatment. Age ranged from 4 to 67 years with the median age being 27 years. Median follow-up was 8 years. Local control was achieved in nine of nine patients or 100% with successful surgical resection, i.e., minimal residual disease, followed by postoperative radiation therapy (45 to 65 Gy) was employed. There were no distant failures when the primary site was controlled. Regional lymph node metastases were infrequent: only 13% (two of 15 patients) presented with positive nodes. Three of four patients treated initially with surgery alone had a local recurrence, two of which were successfully salvaged by combined therapy. There were four patients treated with radiation therapy alone: three had persistent disease after radiation therapy, and one patient was controlled with 65 Gy. Olfactory neuroblastoma has a propensity to recur locally when treated with surgery alone. The authors' experience suggests excellent local control can be achieved with surgery immediately followed by radiation therapy. Thus the authors recommend planned combined treatment for all resectable lesions.

  8. Autonomous Visual Navigation of an Indoor Environment Using a Parsimonious, Insect Inspired Familiarity Algorithm

    PubMed Central

    Brayfield, Brad P.

    2016-01-01

    The navigation of bees and ants from hive to food and back has captivated people for more than a century. Recently, the Navigation by Scene Familiarity Hypothesis (NSFH) has been proposed as a parsimonious approach that is congruent with the limited neural elements of these insects’ brains. In the NSFH approach, an agent completes an initial training excursion, storing images along the way. To retrace the path, the agent scans the area and compares the current scenes to those previously experienced. By turning and moving to minimize the pixel-by-pixel differences between encountered and stored scenes, the agent is guided along the path without having memorized the sequence. An important premise of the NSFH is that the visual information of the environment is adequate to guide navigation without aliasing. Here we demonstrate that an image landscape of an indoor setting possesses ample navigational information. We produced a visual landscape of our laboratory and part of the adjoining corridor consisting of 2816 panoramic snapshots arranged in a grid at 12.7-cm centers. We show that pixel-by-pixel comparisons of these images yield robust translational and rotational visual information. We also produced a simple algorithm that tracks previously experienced routes within our lab based on an insect-inspired scene familiarity approach and demonstrate that adequate visual information exists for an agent to retrace complex training routes, including those where the path’s end is not visible from its origin. We used this landscape to systematically test the interplay of sensor morphology, angles of inspection, and similarity threshold with the recapitulation performance of the agent. Finally, we compared the relative information content and chance of aliasing within our visually rich laboratory landscape to scenes acquired from indoor corridors with more repetitive scenery. PMID:27119720

  9. Pathogen Persistence in the Environment and Insect-Baculovirus Interactions: Disease-Density Thresholds, Epidemic Burnout and Insect Outbreaks

    PubMed Central

    Fuller, Emma; Elderd, Bret D.

    2013-01-01

    Classical epidemic theory focuses on directly transmitted pathogens, but many pathogens are instead transmitted when hosts encounter infectious particles. Theory has shown that for such diseases pathogen persistence time in the environment can strongly affect disease dynamics, but estimates of persistence time, and consequently tests of the theory, are extremely rare. We consider the consequences of persistence time for the dynamics of the gypsy moth baculovirus, a pathogen transmitted when larvae consume foliage contaminated with particles released from infectious cadavers. Using field-transmission experiments, we are able to estimate persistence time under natural conditions, and inserting our estimates into a standard epidemic model suggests that epidemics are often terminated by a combination of pupation and burnout, rather than by burnout alone as predicted by theory. Extending our models to allow for multiple generations, and including environmental transmission over the winter, suggests that the virus may survive over the long term even in the absence of complex persistence mechanisms, such as environmental reservoirs or covert infections. Our work suggests that estimates of persistence times can lead to a deeper understanding of environmentally transmitted pathogens, and illustrates the usefulness of experiments that are closely tied to mathematical models. PMID:22322229

  10. Insects from the grazing food web favoured the evolutionary habitat shift to bright environments in araneoid spiders.

    PubMed

    Miyashita, Tadashi; Shimazaki, Aya

    2006-12-22

    The Araneoidea comprises a diverse group of web-building spiders, and part of this diversity is believed attributable to habitat expansion to bright environments. We clarified the fitness-related advantages of living in such environments by examining prey availability and the growth rates of 10 species in three families inhabiting grassland (bright) and forest understory (dim) habitats. Spiders in the grassland habitat captured more prey, derived mainly from the grazing food web, than those in the forest-floor environment, and this difference was manifested in their growth rate. Independent contrasts indicated that increased utilization of insects from the grazing food web led to an evolutionary increase in adult body size. These results suggest that the shift to bright environments enabled araneoid spiders to evolve diverse life-history traits, including rapid growth and large size, which were not possible in dim environments.

  11. Insects associated with hospital environment in Egypt with special reference to the medically important species.

    PubMed

    Kenawy, Mohamed A; Amer, Hanan S; Lotfy, Nadia M; Khamis, Nagwa; Abdel-Hamid, Yousrya M

    2014-12-01

    A study was planned to examine the insect fauna associated with two hospitals: urban (A) in Cairo and rural (B) in Banha, Egypt with varying hygienic levels and their adjacent residential areas (AC) and (BC), respectively and to investigate the effect of hygienic level on species composition and relative abundance. A total of 22 species belonging to 7 orders and 15 families were reported in the four study areas of which, Dipterous flies were the most common (8/22, 36.36% species). A total of 5257 adults were collected of which Dipterous flies were the abundant (3800, 72.28% insect) and Musca domestica was the most abundant species (3535, 67.24% insect) which was present in all areas where it was more common / predominant species (21.94%-90.91% insect). Moreover, higher densities of M domestica were in (B) and BC than in (A) or (AC). The heavily infested area was AC (54.55% species) followed by (A), (BC) and (B) however, the total number of the collected insects was higher in (BC) and (B) than in (AC) and (A). This was confirmed by finding maximum diversity indices in (AC) and minimum ones in B. In all areas, means of M domestica was more common during summer/autumn and spring than in the winter. Periplaneta americana collected oily during autumn in AC and was more common in autumn in (BC) while Blatella germanica collected only during summer in (AC) and was more common in autumn in (B). The prevalence and higher abundance of the medically important species mainly M domestica, P. americana and B. germanica in rural hospital than in urban one attribute mainly to the lower hygienic level of rural hospital This require a control program based mainly on sanitation supplemented by other measures to overcome the risk of disease transmission by such insects

  12. The effect of spaceflight on mouse olfactory bulb volume, neurogenesis, and cell death indicates the protective effect of novel environment

    PubMed Central

    Latchney, Sarah E.; Rivera, Phillip D.; Mao, Xiao W.; Ferguson, Virginia L.; Bateman, Ted A.; Stodieck, Louis S.; Nelson, Gregory A.

    2014-01-01

    Space missions necessitate physiological and psychological adaptations to environmental factors not present on Earth, some of which present significant risks for the central nervous system (CNS) of crewmembers. One CNS region of interest is the adult olfactory bulb (OB), as OB structure and function are sensitive to environmental- and experience-induced regulation. It is currently unknown how the OB is altered by spaceflight. In this study, we evaluated OB volume and neurogenesis in mice shortly after a 13-day flight on Space Shuttle Atlantis [Space Transport System (STS)-135] relative to two groups of control mice maintained on Earth. Mice housed on Earth in animal enclosure modules that mimicked the conditions onboard STS-135 (AEM-Ground mice) had greater OB volume relative to mice maintained in standard housing on Earth (Vivarium mice), particularly in the granule (GCL) and glomerular (GL) cell layers. AEM-Ground mice also had more OB neuroblasts and fewer apoptotic cells relative to Vivarium mice. However, the AEM-induced increase in OB volume and neurogenesis was not seen in STS-135 mice (AEM-Flight mice), suggesting that spaceflight may have negated the positive effects of the AEM. In fact, when OB volume of AEM-Flight mice was considered, there was a greater density of apoptotic cells relative to AEM-Ground mice. Our findings suggest that factors present during spaceflight have opposing effects on OB size and neurogenesis, and provide insight into potential strategies to preserve OB structure and function during future space missions. PMID:24744382

  13. Innate and Learned Olfactory Responses in a Wild Population of the Egg Parasitoid Trichogramma (Hymenoptera: Trichogrammatidae)

    PubMed Central

    Wilson, J. Keaton; Woods, H. Arthur

    2016-01-01

    Parasitoid insects face the fundamental problem of finding a suitable host in environments filled with competing stimuli. Many are deft sensors of olfactory cues emitted by other insects and the plants they live on, and use these cues to find hosts. Using olfactory cues from host-plants is effective because plants release volatile organic compounds (VOCs), in response to herbivory or oviposition, that contain information about the presence of hosts. However, plant-produced cues can also be misleading because they are influenced by a variety of stimuli (abiotic variation, infection and multiple sources of induction via herbivory or oviposition). Flexible behavior is one strategy that parasitoids may use to cope with variation in olfactory cues. We examine the innate and learned responses of a natural population of wasp egg parasitoids (Trichogramma deion and Trichogramma sathon) using a series of laboratory and field Y-olfactometer experiments. Wasps typically attack eggs of the hawkmoth Manduca sexta and Manduca quinquemaculata on native Datura wrightii plants in the southwestern United States. We show that Trichogramma wasps responded innately to VOCs produced by D. wrightii and could distinguish plants recently attacked by M. sexta from non-attacked plants. Furthermore, adult Trichogramma wasps were able to learn components of the VOC blend given off by D. wrightii, though they did not learn during exposure as pupae. By further exploring the behavioral ecology of a natural population of Trichogramma, we gain greater insight into how egg parasitoids function in tri-trophic systems. PMID:27965403

  14. Odorant and pheromone receptors in insects.

    PubMed

    Ha, Tal Soo; Smith, Dean P

    2009-01-01

    Since the emergence of the first living cells, survival has hinged on the ability to detect and localize chemicals in the environment. Modern animal species ranging from insects to mammals express large odorant receptor repertoires to detect the structurally diverse array of volatile molecules important for survival. Despite the essential nature of chemical detection, there is surprising diversity in the signaling mechanisms that different species use for odorant detection. In vertebrates, odorant receptors are classical G-protein coupled, seven transmembrane receptors that activate downstream effector enzymes that, in turn, produce second messengers that open ion channels. However, recent work reveals that insects have adopted different strategies to detect volatile chemicals. In Drosophila, the odorant receptors, predicted to have seven transmembrane domains, have reversed membrane topology compared to classical G-protein coupled receptors. Furthermore, insect odorant receptors appear to form odorant-gated ion channels. Pheromone detection in insects is even more unusual, utilizing soluble, extracellular receptors that undergo conformational activation. These alternate olfactory signaling strategies are discussed in terms of receptor design principles.

  15. Insect Resistance

    USDA-ARS?s Scientific Manuscript database

    Insect pests exhibit a diverse array of genetic-based responses when interacting with crop systems; these changes can be in response to pathogens, symbiotic microbes, host plants, chemicals, and the environment. Agricultural research has for decades focused on gathering crucial information on the bi...

  16. Olfactory memory formation in Drosophila: from molecular to systems neuroscience.

    PubMed

    Davis, Ronald L

    2005-01-01

    The olfactory nervous system of insects and mammals exhibits many similarities, which suggests that the mechanisms for olfactory learning may be shared. Molecular genetic investigations of Drosophila learning have uncovered numerous genes whose gene products are essential for olfactory memory formation. Recent studies of the products of these genes have continued to expand the range of molecular processes known to underlie memory formation. Recent research has also broadened the neuroanatomical areas thought to mediate olfactory learning to include the antennal lobes in addition to a previously accepted and central role for the mushroom bodies. The roles for neurons extrinsic to the mushroom body neurons are becoming better defined. Finally, the genes identified to participate in Drosophila olfactory learning have conserved roles in mammalian organisms, highlighting the value of Drosophila for gene discovery.

  17. Functional Sub-Circuits of the Olfactory System Viewed from the Olfactory Bulb and the Olfactory Tubercle.

    PubMed

    Yamaguchi, Masahiro

    2017-01-01

    Understanding of the olfactory neural circuits has progressed beyond analysis of how odor information from the external environment is processed in the brain. While spatially-organized sub-circuits were found to exist up to the olfactory bulb (OB), the arrangement in the olfactory cortex (OC), especially in its representative piriform cortex (PC), appears diffuse and dispersed. An emerging view is that the activity of OC neurons may not simply encode odor identity but rather encode plastic odor information such as odor value. Although many studies support this notion, odor value can be either positive or negative, and the existence of sub-circuits corresponding to individual value types is not well explored. To address this question, I introduce here two olfactory areas other than the PC, OB and olfactory tubercle (OT) whose analysis may facilitate understanding of functional sub-circuits related to different odor values. Peripheral and centrifugal inputs to the OB are considered to relate to odor identity and odor value, respectively and centrifugal inputs to the OB potentially represent different odor values during different behavioral periods. The OT has spatially-segregated functional domains related to distinct motivated and hedonic behaviors. Thus, the OT provides a good starting point from which functional sub-circuits across various olfactory regions can be traced. Further analysis across wide areas of the olfactory system will likely reveal the functional sub-circuits that link odor identity with distinct odor values and direct distinct odor-induced motivated and hedonic behaviors.

  18. Impact of environmental olfactory cues on hand hygiene behaviour in a simulated hospital environment: a randomized study.

    PubMed

    Birnbach, D J; King, D; Vlaev, I; Rosen, L F; Harvey, P D

    2013-09-01

    This study investigated the impact of a fresh scent on the rate of hand hygiene compliance (HHC) among novice healthcare providers. In all, 165 participants examined a standardized patient with one sample exposed to fresh scent (N = 79) and the other exposed to the standard environment (N = 86). Hand hygiene behaviours were tracked before patient contact using video surveillance. The standard environment group had an HHC rate of 51% whereas participants in the fresh scent group had a higher HHC rate of 80% (P < 0.001). These data demonstrate that hand hygiene behaviour may be subconsciously influenced by cues in the environment. © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  19. Olfactory imprinting is correlated with changes in gene expression in the olfactory epithelia of the zebrafish.

    PubMed

    Harden, Maegan V; Newton, Lucy A; Lloyd, Russell C; Whitlock, Kathleen E

    2006-11-01

    Odors experienced as juveniles can have significant effects on the behavior of mature organisms. A dramatic example of this occurs in salmon, where the odors experienced by developing fish determine the river to which they return as adults. Further examples of olfactory memories are found in many animals including vertebrates and invertebrates. Yet, the cellular and molecular bases underlying the formation of olfactory memory are poorly understood. We have devised a series of experiments to determine whether zebrafish can form olfactory memories much like those observed in salmonids. Here we show for the first time that zebrafish form and retain olfactory memories of an artificial odorant, phenylethyl alcohol (PEA), experienced as juveniles. Furthermore, we demonstrate that exposure to PEA results in changes in gene expression within the olfactory sensory system. These changes are evident by in situ hybridization in the olfactory epithelium of the developing zebrafish. Strikingly, our analysis by in situ hybridization demonstrates that the transcription factor, otx2, is up regulated in the olfactory sensory epithelia in response to PEA. This increase is evident at 2-3 days postfertilization and is maintained in the adult animals. We propose that the changes in otx2 gene expression are manifest as an increase in the number of neuronal precursors in the cells olfactory epithelium of the odor-exposed fish. Thus, our results reveal a role for the environment in controlling gene expression in the developing peripheral nervous system.

  20. Olfactory specialization for perfume collection in male orchid bees.

    PubMed

    Mitko, Lukasz; Weber, Marjorie G; Ramirez, Santiago R; Hedenström, Erik; Wcislo, William T; Eltz, Thomas

    2016-05-15

    Insects rely on the olfactory system to detect a vast diversity of airborne molecules in their environment. Highly sensitive olfactory tuning is expected to evolve when detection of a particular chemical with great precision is required in the context of foraging and/or finding mates. Male neotropical orchid bees (Euglossini) collect odoriferous substances from multiple sources, store them in specialized tibial pouches and later expose them at display sites, presumably as mating signals to females. Previous analysis of tibial compounds among sympatric species revealed substantial chemical disparity in chemical composition among lineages with outstanding divergence between closely related species. Here, we tested whether specific perfume phenotypes coevolve with matching olfactory adaptations in male orchid bees to facilitate the location and harvest of species-specific perfume compounds. We conducted electroantennographic (EAG) measurements on males of 15 sympatric species in the genus Euglossa that were stimulated with 18 compounds present in variable proportions in male hind tibiae. Antennal response profiles were species-specific across all 15 species, but there was no conspicuous differentiation between closely related species. Instead, we found that the observed variation in EAG activity follows a Brownian motion model of trait evolution, where the probability of differentiation increases proportionally with lineage divergence time. However, we identified strong antennal responses for some chemicals that are present as major compounds in the perfume of the same species, thus suggesting that sensory specialization has occurred within multiple lineages. This sensory specialization was particularly apparent for semi-volatile molecules ('base note' compounds), thus supporting the idea that such compounds play an important role in chemical signaling of euglossine bees. Overall, our study found no close correspondence between antennal responses and behavioral

  1. 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.

  2. Depth information in natural environments derived from optic flow by insect motion detection system: a model analysis.

    PubMed

    Schwegmann, Alexander; Lindemann, Jens P; Egelhaaf, Martin

    2014-01-01

    Knowing the depth structure of the environment is crucial for moving animals in many behavioral contexts, such as collision avoidance, targeting objects, or spatial navigation. An important source of depth information is motion parallax. This powerful cue is generated on the eyes during translatory self-motion with the retinal images of nearby objects moving faster than those of distant ones. To investigate how the visual motion pathway represents motion-based depth information we analyzed its responses to image sequences recorded in natural cluttered environments with a wide range of depth structures. The analysis was done on the basis of an experimentally validated model of the visual motion pathway of insects, with its core elements being correlation-type elementary motion detectors (EMDs). It is the key result of our analysis that the absolute EMD responses, i.e., the motion energy profile, represent the contrast-weighted nearness of environmental structures during translatory self-motion at a roughly constant velocity. In other words, the output of the EMD array highlights contours of nearby objects. This conclusion is largely independent of the scale over which EMDs are spatially pooled and was corroborated by scrutinizing the motion energy profile after eliminating the depth structure from the natural image sequences. Hence, the well-established dependence of correlation-type EMDs on both velocity and textural properties of motion stimuli appears to be advantageous for representing behaviorally relevant information about the environment in a computationally parsimonious way.

  3. Depth information in natural environments derived from optic flow by insect motion detection system: a model analysis

    PubMed Central

    Schwegmann, Alexander; Lindemann, Jens P.; Egelhaaf, Martin

    2014-01-01

    Knowing the depth structure of the environment is crucial for moving animals in many behavioral contexts, such as collision avoidance, targeting objects, or spatial navigation. An important source of depth information is motion parallax. This powerful cue is generated on the eyes during translatory self-motion with the retinal images of nearby objects moving faster than those of distant ones. To investigate how the visual motion pathway represents motion-based depth information we analyzed its responses to image sequences recorded in natural cluttered environments with a wide range of depth structures. The analysis was done on the basis of an experimentally validated model of the visual motion pathway of insects, with its core elements being correlation-type elementary motion detectors (EMDs). It is the key result of our analysis that the absolute EMD responses, i.e., the motion energy profile, represent the contrast-weighted nearness of environmental structures during translatory self-motion at a roughly constant velocity. In other words, the output of the EMD array highlights contours of nearby objects. This conclusion is largely independent of the scale over which EMDs are spatially pooled and was corroborated by scrutinizing the motion energy profile after eliminating the depth structure from the natural image sequences. Hence, the well-established dependence of correlation-type EMDs on both velocity and textural properties of motion stimuli appears to be advantageous for representing behaviorally relevant information about the environment in a computationally parsimonious way. PMID:25136314

  4. 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.

  5. A method for recording behavior and multineuronal CNS activity from tethered insects flying in virtual space.

    PubMed

    Gray, John R; Pawlowski, Vincent; Willis, Mark A

    2002-10-30

    We describe a low cost, novel virtual reality-based insect flight simulator that combines visual, olfactory and mechanosensory stimuli with multichannel neurophysiological recording techniques. Three-dimensional visual environments were created using customized modifications of a first person flight simulator computer game. Experiments could be performed in open-loop, where the flying insect's movement through the environment is 'driven' by the human operator, or in closed-loop where the movement of the environment is controlled by optically sensed movements of the insect's abdomen. During flight, we recorded multineuronal activity from the ventral nerve cord between the brain and thoracic ganglia. Results show that in open-loop conditions, induced turns of the environment evoked characteristic compensatory optomotor responses. Coordination of wing and body kinematics was similar to that observed in free flight. In closed-loop conditions, the insect was able to navigate through the simulated environment and produce flight tracks in response to presentation of pheromone that resemble those observed in free flight. We discuss the effectiveness of this preparation and its utility for addressing specific questions of insect flight as well as general questions in neuroethology. Copyright 2002 Elsevier Science B.V.

  6. Cladistic Analysis of Olfactory and Vomeronasal Systems

    PubMed Central

    Ubeda-Bañon, Isabel; Pro-Sistiaga, Palma; Mohedano-Moriano, Alicia; Saiz-Sanchez, Daniel; de la Rosa-Prieto, Carlos; Gutierrez-Castellanos, Nicolás; Lanuza, Enrique; Martinez-Garcia, Fernando; Martinez-Marcos, Alino

    2010-01-01

    Most tetrapods possess two nasal organs for detecting chemicals in their environment, which are the sensory detectors of the olfactory and vomeronasal systems. The seventies’ view that the olfactory system was only devoted to sense volatiles, whereas the vomeronasal system was exclusively specialized for pheromone detection was challenged by accumulating data showing deep anatomical and functional interrelationships between both systems. In addition, the assumption that the vomeronasal system appeared as an adaptation to terrestrial life is being questioned as well. The aim of the present work is to use a comparative strategy to gain insight in our understanding of the evolution of chemical “cortex.” We have analyzed the organization of the olfactory and vomeronasal cortices of reptiles, marsupials, and placental mammals and we have compared our findings with data from other taxa in order to better understand the evolutionary history of the nasal sensory systems in vertebrates. The olfactory and vomeronsasal cortices have been re-investigated in garter snakes (Thamnophis sirtalis), short-tailed opossums (Monodelphis domestica), and rats (Rattus norvegicus) by tracing the efferents of the main and accessory olfactory bulbs using injections of neuroanatomical anterograde tracers (dextran-amines). In snakes, the medial olfactory tract is quite evident, whereas the main vomeronasal-recipient structure, the nucleus sphaericus is a folded cortical-like structure, located at the caudal edge of the amygdala. In marsupials, which are acallosal mammals, the rhinal fissure is relatively dorsal and the olfactory and vomeronasal cortices relatively expanded. Placental mammals, like marsupials, show partially overlapping olfactory and vomeronasal projections in the rostral basal telencephalon. These data raise the interesting question of how the telencephalon has been re-organized in different groups according to the biological relevance of chemical senses. PMID:21290004

  7. Cladistic analysis of olfactory and vomeronasal systems.

    PubMed

    Ubeda-Bañon, Isabel; Pro-Sistiaga, Palma; Mohedano-Moriano, Alicia; Saiz-Sanchez, Daniel; de la Rosa-Prieto, Carlos; Gutierrez-Castellanos, Nicolás; Lanuza, Enrique; Martinez-Garcia, Fernando; Martinez-Marcos, Alino

    2011-01-01

    Most tetrapods possess two nasal organs for detecting chemicals in their environment, which are the sensory detectors of the olfactory and vomeronasal systems. The seventies' view that the olfactory system was only devoted to sense volatiles, whereas the vomeronasal system was exclusively specialized for pheromone detection was challenged by accumulating data showing deep anatomical and functional interrelationships between both systems. In addition, the assumption that the vomeronasal system appeared as an adaptation to terrestrial life is being questioned as well. The aim of the present work is to use a comparative strategy to gain insight in our understanding of the evolution of chemical "cortex." We have analyzed the organization of the olfactory and vomeronasal cortices of reptiles, marsupials, and placental mammals and we have compared our findings with data from other taxa in order to better understand the evolutionary history of the nasal sensory systems in vertebrates. The olfactory and vomeronsasal cortices have been re-investigated in garter snakes (Thamnophis sirtalis), short-tailed opossums (Monodelphis domestica), and rats (Rattus norvegicus) by tracing the efferents of the main and accessory olfactory bulbs using injections of neuroanatomical anterograde tracers (dextran-amines). In snakes, the medial olfactory tract is quite evident, whereas the main vomeronasal-recipient structure, the nucleus sphaericus is a folded cortical-like structure, located at the caudal edge of the amygdala. In marsupials, which are acallosal mammals, the rhinal fissure is relatively dorsal and the olfactory and vomeronasal cortices relatively expanded. Placental mammals, like marsupials, show partially overlapping olfactory and vomeronasal projections in the rostral basal telencephalon. These data raise the interesting question of how the telencephalon has been re-organized in different groups according to the biological relevance of chemical senses.

  8. Forward and Back: Motifs of Inhibition in Olfactory Processing

    PubMed Central

    Bazhenov, Maxim; Stopfer, Mark

    2016-01-01

    The remarkable performance of the olfactory system in classifying and categorizing the complex olfactory environment is built upon several basic neural circuit motifs. These include forms of inhibition that may play comparable roles in widely divergent species. In this issue of Neuron, a new study by Stokes and Isaacson sheds light on how elementary types of inhibition dynamically interact. PMID:20696373

  9. 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

  10. Olfactory Learning in Individually Assayed Drosophila Larvae

    PubMed Central

    Scherer, Sabine; Stocker, Reinhard F.; Gerber, Bertram

    2003-01-01

    Insect and mammalian olfactory systems are strikingly similar. Therefore, Drosophila can be used as a simple model for olfaction and olfactory learning. The brain of adult Drosophila, however, is still complex. We therefore chose to work on the larva with its yet simpler but adult-like olfactory system and provide evidence for olfactory learning in individually assayed Drosophila larvae. We developed a differential conditioning paradigm in which odorants are paired with positive (“+” fructose) or negative (“-” quinine or sodium chloride) gustatory reinforcers. Test performance of individuals from two treatment conditions is compared—one received odorant A with the positive reinforcer and odorant B with a negative reinforcer (A+/B-); animals from the other treatment condition were trained reciprocally (A-/B+). During test, differences in choice between A and B of individuals having undergone either A+/B- or A-/B+ training therefore indicate associative learning. We provide such evidence for both combinations of reinforcers; this was replicable across repetitions, laboratories, and experimenters. We further show that breaks improve performance, in accord with basic principles of associative learning. The present individual assay will facilitate electrophysiological studies, which necessarily use individuals. As such approaches are established for the larval neuromuscular synapse, but not in adults, an individual larval learning paradigm will serve to link behavioral levels of analysis to synaptic physiology. PMID:12773586

  11. A computational model of conditioning inspired by Drosophila olfactory system.

    PubMed

    Faghihi, Faramarz; Moustafa, Ahmed A; Heinrich, Ralf; Wörgötter, Florentin

    2017-03-01

    Recent studies have demonstrated that Drosophila melanogaster (briefly Drosophila) can successfully perform higher cognitive processes including second order olfactory conditioning. Understanding the neural mechanism of this behavior can help neuroscientists to unravel the principles of information processing in complex neural systems (e.g. the human brain) and to create efficient and robust robotic systems. In this work, we have developed a biologically-inspired spiking neural network which is able to execute both first and second order conditioning. Experimental studies demonstrated that volume signaling (e.g. by the gaseous transmitter nitric oxide) contributes to memory formation in vertebrates and invertebrates including insects. Based on the existing knowledge of odor encoding in Drosophila, the role of retrograde signaling in memory function, and the integration of synaptic and non-synaptic neural signaling, a neural system is implemented as Simulated fly. Simulated fly navigates in a two-dimensional environment in which it receives odors and electric shocks as sensory stimuli. The model suggests some experimental research on retrograde signaling to investigate neural mechanisms of conditioning in insects and other animals. Moreover, it illustrates a simple strategy to implement higher cognitive capabilities in machines including robots.

  12. Anhydrobiotic insect Polypedilum vanderplanki: molecular mechanisms of DNA and protein protection against extreme environments.

    NASA Astrophysics Data System (ADS)

    Gusev, Oleg; Nakahara, Yuichi; Kikawada, Takahiro; Levinskikh, Margarita; Sychev, Vladimir; Okuda, Takashi

    Some organisms showing no sign of living due to complete desiccation are nevertheless able to resume active life after rehydration. This peculiar biological state is referred to as "anhydrobiosis". Larvae of the sleeping chironomid, P. vanderplanki living in temporary pools in semi-arid areas on the African continent become completely desiccated upon drought, but can revive after water becomes available upon the next rain. The dried larvae can stand other extreme conditions, such as exposure to 100˚C, -270˚C, 100We have adopted several methods to evaluated DNA damage in cells of P. vanderplanki and cloned and analyzed expression of the main agent of genetic stress response showing that the larvae possess highly developed anti-stress genetic system, involving anti-oxidative stress genes, hsp and DNA reparation enzymes acting together to provide stability of proteins and DNA in the absence of water. From 2005, dried larvae were included in a number of research programs, including exposition to space environments onboard ISS and long-term exposure to outer space environment outside of ISS ("Expose-R" and"Biorisk" projects) and now are being considered for including into the Phobos-Grunt mission as a testing organism to analyze capability of resting stages of multicellular organism to interplanetary flights.

  13. 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…

  14. 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…

  15. Gene discovery and pre-breeding in cereals for broad resistance against insects adaptable to variable environments

    USDA-ARS?s Scientific Manuscript database

    Climate change is expected to cause drastic changes in the incidence of disease and pests throughout the world, also leading to the occurrence of highly variable insect pests. One approach to minimize the losses in crop yields due to highly variable insects is the introgression of multiple resistan...

  16. Posttraumatic olfactory dysfunction.

    PubMed

    Coelho, Daniel H; Costanzo, Richard M

    2016-04-01

    Impairment of smell may occur following injury to any portion of the olfactory tract, from nasal cavity to brain. A thorough understanding of the anatomy and pathophysiology combined with comprehensively obtained history, physical exam, olfactory testing, and neuroimaging may help to identify the mechanism of dysfunction and suggest possible treatments. Although most olfactory deficits are neuronal mediated and therefore currently unable to be corrected, promising technology may provide novel treatment options for those most affected. Until that day, patient counseling with compensatory strategies and reassurance is essential for the maintenance of safety and QoL in this unique and challenging patient population.

  17. Genetic architecture of metabolic rate: environment specific epistasis between mitochondrial and nuclear genes in an insect.

    PubMed

    Arnqvist, Göran; Dowling, Damian K; Eady, Paul; Gay, Laurene; Tregenza, Tom; Tuda, Midori; Hosken, David J

    2010-12-01

    The extent to which mitochondrial DNA (mtDNA) variation is involved in adaptive evolutionary change is currently being reevaluated. In particular, emerging evidence suggests that mtDNA genes coevolve with the nuclear genes with which they interact to form the energy producing enzyme complexes in the mitochondria. This suggests that intergenomic epistasis between mitochondrial and nuclear genes may affect whole-organism metabolic phenotypes. Here, we use crossed combinations of mitochondrial and nuclear lineages of the seed beetle Callosobruchus maculatus and assay metabolic rate under two different temperature regimes. Metabolic rate was affected by an interaction between the mitochondrial and nuclear lineages and the temperature regime. Sequence data suggests that mitochondrial genetic variation has a role in determining the outcome of this interaction. Our genetic dissection of metabolic rate reveals a high level of complexity, encompassing genetic interactions over two genomes, and genotype × genotype × environment interactions. The evolutionary implications of these results are twofold. First, because metabolic rate is at the root of life histories, our results provide insights into the complexity of life-history evolution in general, and thermal adaptation in particular. Second, our results suggest a mechanism that could contribute to the maintenance of nonneutral mtDNA polymorphism. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

  18. Innate and Learned Olfactory Responses in a Wild Population of the Egg Parasitoid Trichogramma (Hymenoptera: Trichogrammatidae).

    PubMed

    Wilson, J Keaton; Woods, H Arthur

    2016-01-01

    Parasitoid insects face the fundamental problem of finding a suitable host in environments filled with competing stimuli. Many are deft sensors of olfactory cues emitted by other insects and the plants they live on, and use these cues to find hosts. Using olfactory cues from host-plants is effective because plants release volatile organic compounds (VOCs), in response to herbivory or oviposition, that contain information about the presence of hosts. However, plant-produced cues can also be misleading because they are influenced by a variety of stimuli (abiotic variation, infection and multiple sources of induction via herbivory or oviposition). Flexible behavior is one strategy that parasitoids may use to cope with variation in olfactory cues. We examine the innate and learned responses of a natural population of wasp egg parasitoids (Trichogramma deion and Trichogramma sathon) using a series of laboratory and field Y-olfactometer experiments. Wasps typically attack eggs of the hawkmoth Manduca sexta and Manduca quinquemaculata on native Datura wrightii plants in the southwestern United States. We show that Trichogramma wasps responded innately to VOCs produced by D. wrightii and could distinguish plants recently attacked by M. sexta from non-attacked plants. Furthermore, adult Trichogramma wasps were able to learn components of the VOC blend given off by D. wrightii, though they did not learn during exposure as pupae. By further exploring the behavioral ecology of a natural population of Trichogramma, we gain greater insight into how egg parasitoids function in tri-trophic systems. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

  19. Multiple activities of insect repellents on odorant receptors in mosquitoes

    USDA-ARS?s Scientific Manuscript database

    Several lines of evidence suggest that insect repellent molecules reduce mosquito-host contacts by interacting with odorants and odorant receptors (ORs) ultimately affecting olfactory-driven behaviors. We describe the molecular effects of ten insect repellents and a pyrethroid insecticide with known...

  20. Changes in Olfactory Sensory Neuron Physiology and Olfactory Perceptual Learning After Odorant Exposure in Adult Mice

    PubMed Central

    Kass, Marley D.; Guang, Stephanie A.; Moberly, Andrew H.

    2016-01-01

    The adult olfactory system undergoes experience-dependent plasticity to adapt to the olfactory environment. This plasticity may be accompanied by perceptual changes, including improved olfactory discrimination. Here, we assessed experience-dependent changes in the perception of a homologous aldehyde pair by testing mice in a cross-habituation/dishabituation behavioral paradigm before and after a week-long ester-odorant exposure protocol. In a parallel experiment, we used optical neurophysiology to observe neurotransmitter release from olfactory sensory neuron (OSN) terminals in vivo, and thus compared primary sensory representations of the aldehydes before and after the week-long ester-odorant exposure in individual animals. Mice could not discriminate between the aldehydes during pre-exposure testing, but ester-exposed subjects spontaneously discriminated between the homologous pair after exposure, whereas home cage control mice cross-habituated. Ester exposure did not alter the spatial pattern, peak magnitude, or odorant-selectivity of aldehyde-evoked OSN input to olfactory bulb glomeruli, but did alter the temporal dynamics of that input to make the time course of OSN input more dissimilar between odorants. Together, these findings demonstrate that odor exposure can induce both physiological and perceptual changes in odor processing, and suggest that changes in the temporal patterns of OSN input to olfactory bulb glomeruli could induce differences in odor quality. PMID:26514410

  1. Functional Specialization of Olfactory Glomeruli in a Moth

    NASA Astrophysics Data System (ADS)

    Hansson, Bill S.; Ljungberg, Hakan; Hallberg, Eric; Lofstedt, Christer

    1992-05-01

    The specific function of the glomerular structures present in the antennal lobes or olfactory bulbs of organisms ranging from insects to humans has been obscure because of limitations in neuronal marking methods. By tracing individual neurons in the moth Agrotis segetum, it was determined that physiologically distinct types of pheromone receptor neurons project axons to different regions of the macroglomerular complex (MGC). Each glomerulus making up the MGC has a specific functional identity, initially processing information about one specific pheromone component. This indicates that, at least through the first stage of synapses, olfactory information moves through labeled lines.

  2. Dual olfactory pathway in Hymenoptera: evolutionary insights from comparative studies.

    PubMed

    Rössler, Wolfgang; Zube, Christina

    2011-07-01

    In the honeybee (Apis mellifera) and carpenter ant (Camponotus floridanus) the antennal lobe output is connected to higher brain centers by a dual olfactory pathway. Two major sets of uniglomerular projection neurons innervate glomeruli from two antennal-lobe hemispheres and project via a medial and a lateral antennal-lobe protocerebral tract in opposite sequence to the mushroom bodies and lateral horn. Comparison across insects suggests that the lateral projection neuron tract represents a special feature of Hymenoptera. We hypothesize that this promotes advanced olfactory processing associated with chemical communication, orientation and social interactions. To test whether a dual olfactory pathway is restricted to social Hymenoptera, we labeled the antennal lobe output tracts in selected species using fluorescent tracing and confocal imaging. Our results show that a dual pathway from the antennal lobe to the mushroom bodies is present in social bees, basal and advanced ants, solitary wasps, and in one of two investigated species of sawflies. This indicates that a dual olfactory pathway is not restricted to social species and may have evolved in basal Hymenoptera. We suggest that associated advances in olfactory processing represent a preadaptation for life styles with high demands on olfactory discrimination like parasitoism, central place foraging, and sociality.

  3. Unexpected Effects of Low Doses of a Neonicotinoid Insecticide on Behavioral Responses to Sex Pheromone in a Pest Insect

    PubMed Central

    Rabhi, Kaouther K.; Esancy, Kali; Voisin, Anouk; Crespin, Lucille; Le Corre, Julie; Tricoire-Leignel, Hélène; Anton, Sylvia; Gadenne, Christophe

    2014-01-01

    In moths, which include many agricultural pest species, males are attracted by female-emitted sex pheromones. Although integrated pest management strategies are increasingly developed, most insect pest treatments rely on widespread use of neurotoxic chemicals, including neonicotinoid insecticides. Residual accumulation of low concentrations of these insecticides in the environment is known to be harmful to beneficial insects such as honey bees. This environmental stress probably acts as an “info-disruptor” by modifying the chemical communication system, and therefore decreases chances of reproduction in target insects that largely rely on olfactory communication. However, low doses of pollutants could on the contrary induce adaptive processes in the olfactory pathway, thus enhancing reproduction. Here we tested the effects of acute oral treatments with different low doses of the neonicotinoid clothianidin on the behavioral responses to sex pheromone in the moth Agrotis ipsilon using wind tunnel experiments. We show that low doses of clothianidin induce a biphasic effect on pheromone-guided behavior. Surprisingly, we found a hormetic-like effect, improving orientation behavior at the LD20 dose corresponding to 10 ng clothianidin. On the contrary, a negative effect, disturbing orientation behavior, was elicited by a treatment with a dose below the LD0 dose corresponding to 0.25 ng clothianidin. No clothianidin effect was observed on behavioral responses to plant odor. Our results indicate that risk assessment has to include unexpected effects of residues on the life history traits of pest insects, which could then lead to their adaptation to environmental stress. PMID:25517118

  4. Expression and function of the empty spiracles gene in olfactory sense organ development of Drosophila melanogaster.

    PubMed

    Sen, Sonia; Hartmann, Beate; Reichert, Heinrich; Rodrigues, Veronica

    2010-11-01

    In Drosophila, the cephalic gap gene empty spiracles plays key roles in embryonic patterning of the peripheral and central nervous system. During postembryonic development, it is involved in the development of central olfactory circuitry in the antennal lobe of the adult. However, its possible role in the postembryonic development of peripheral olfactory sense organs has not been investigated. Here, we show that empty spiracles acts in a subset of precursors that generate the olfactory sense organs of the adult antenna. All empty spiracles-expressing precursor cells co-express the proneural gene amos and the early patterning gene lozenge. Moreover, the expression of empty spiracles in these precursor cells is dependent on both amos and lozenge. Functional analysis reveals two distinct roles of empty spiracles in the development of olfactory sense organs. Genetic interaction studies in a lozenge-sensitized background uncover a requirement of empty spiracles in the formation of trichoid and basiconic olfactory sensilla. MARCM-based clonal mutant analysis reveals an additional role during axonal targeting of olfactory sensory neurons to glomeruli within the antennal lobe. Our findings on empty spiracles action in olfactory sense organ development complement previous studies that demonstrate its requirement in olfactory interneurons and, taken together with studies on the murine homologs of empty spiracles, suggest that conserved molecular genetic programs might be responsible for the formation of both peripheral and central olfactory circuitry in insects and mammals.

  5. 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…

  6. 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…

  7. Modulation of early olfactory processing by an octopaminergic reinforcement pathway in the honeybee.

    PubMed

    Farooqui, Tahira; Robinson, Kellie; Vaessin, Harald; Smith, Brian H

    2003-06-15

    Processing of olfactory information in the antennal lobes of insects and olfactory bulbs of vertebrates is modulated by centrifugal inputs that represent reinforcing events. Octopamine release by one such pathway in the honeybee antennal lobe modulates olfactory processing in relation to nectar (sucrose) reinforcement. To test more specifically what role octopamine plays in the antennal lobe, we used two treatments to disrupt an octopamine receptor from Apis mellifera brain (AmOAR) function: (1) an OAR antagonist, mianserin, was used to block receptor function, and (2) AmOAR double-stranded RNA was used to silence receptor expression. Both treatments inhibited olfactory acquisition and recall, but they did not disrupt odor discrimination. These results suggest that octopamine mediates consolidation of a component of olfactory memory at this early processing stage in the antennal lobe. Furthermore, after consolidation, octopamine release becomes essential for recall, which suggests that the modulatory circuits become incorporated as essential components of neural representations that activate odor memory.

  8. The olfactory bulb and the number of its glomeruli in the common marmoset (Callithrix jacchus).

    PubMed

    Moriya-Ito, Keiko; Tanaka, Ikuko; Umitsu, Yoshitomo; Ichikawa, Masumi; Tokuno, Hironobu

    2015-04-01

    The olfactory system has been well studied in mammals such as mice and rats. However, few studies have focused on characterizing this system in diurnal primates that rely on their sense of smell to a lesser extent due to their ecological environment. In the present study, we determined the histological organization of the olfactory bulb in the common marmoset (Callithrix jacchus). We then constructed 3-dimensional models of the glomeruli of the olfactory bulb, and estimated the number of glomeruli. Olfactory glomeruli are the functional units of olfactory processing, and have been investigated in detail using mice. There are approximately 1800 glomeruli in a mouse hemibulb, and olfactory sensory neurons expressing one selected olfactory receptor converge onto one or two glomeruli. Because mice have about 1000 olfactory receptor genes, it is proposed that the number of glomeruli in mammals is nearly double that of olfactory receptor genes. The common marmoset carries only about 400 intact olfactory receptor genes. The present study revealed that the number of glomeruli in a marmoset hemibulb was approximately 1500-1800. This result suggests that the number of glomeruli is not positively correlated with the number of intact olfactory receptor genes in mammals.

  9. Oviposition pheromones in haematophagous insects.

    PubMed

    Seenivasagan, T; Vijayaraghavan, R

    2010-01-01

    Pheromones influencing oviposition behavior in females of haematophagous insects have been the interest of recent past by many group of scientists working on oviposition pheromones. Finding and choosing a good site for oviposition is a challenging task for females of haematophagous insects, especially in those insects which does not have the parental care. Their decisions have far-reaching and profound consequences for the life history of the offspring. In such blood feeding insects, the choice of oviposition site is affected by pheromones, which may function either as deterrents or stimulants in short range, while they may also act as repellents or attractants in long range perception. During the location of a suitable oviposition site for egg laying or a potential host for blood feeding, haematophagous insects mainly use olfactory and visual cues. These pheromones are produced by the ovipositing female or by conspecific larvae co-occurring with gravid females. Adult females detect oviposition pheromones by odor receptors on the antennae, as well as by contact chemoreceptors on tarsi, mouthparts and antennae. Different cues exploited by gravid females from a diversified arena include egg, larva, habitat, microbes, infusions and plant produced volatiles influence the oviposition behavior. Traps baited with pheromones, infusions, and insecticides shall be promising tools for monitoring and control of target insect using integrated vector management strategies. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. Adrenergic modulation of olfactory bulb circuitry affects odor discrimination.

    PubMed

    Doucette, Wilder; Milder, Julie; Restrepo, Diego

    2007-08-01

    A rodent's survival depends upon its ability to perceive odor cues necessary to guide mate selection, sexual behavior, foraging, territorial formation, and predator avoidance. Arguably, the need to discriminate odor cues in a complex olfactory environment requires a highly adaptable olfactory system. Indeed, it has been proposed that context-dependent modulation of the initial sensory relay could alter olfactory perception. Interestingly, 40% of the adrenergic innervation from the locus coeruleus, fibers that are activated by contextual cues, innervates the first relay station in the olfactory system (the main olfactory bulb). Here we utilize restricted pharmacological inhibition of olfactory bulb noradrenergic receptors in awake-behaving animals. We show that combined blockade of alpha and beta adrenergic receptors does not impair two-odor discrimination behavior per se but does impair the ability to discriminate perceptually similar odors. Thus, contextual cues conveyed by noradrenergic fibers alter processing before the second synapse in the olfactory cortex, resulting in tuning of the ability to discriminate between similar odors.

  11. Vision in flying insects.

    PubMed

    Egelhaaf, Martin; Kern, Roland

    2002-12-01

    Vision guides flight behaviour in numerous insects. Despite their small brain, insects easily outperform current man-made autonomous vehicles in many respects. Examples are the virtuosic chasing manoeuvres male flies perform as part of their mating behaviour and the ability of bees to assess, on the basis of visual motion cues, the distance travelled in a novel environment. Analyses at both the behavioural and neuronal levels are beginning to unveil reasons for such extraordinary capabilities of insects. One recipe for their success is the adaptation of visual information processing to the specific requirements of the behavioural tasks and to the specific spatiotemporal properties of the natural input.

  12. Elements of olfactory reception in adult Drosophila melanogaster.

    PubMed

    Martin, Fernando; Boto, Tamara; Gomez-Diaz, Carolina; Alcorta, Esther

    2013-09-01

    The olfactory system of Drosophila has become an attractive and simple model to investigate olfaction because it follows the same organizational principles of vertebrates, and the results can be directly applied to other insects with economic and sanitary relevance. Here, we review the structural elements of the Drosophila olfactory reception organs at the level of the cells and molecules involved. This article is intended to reflect the structural basis underlying the functional variability of the detection of an olfactory universe composed of thousands of odors. At the genetic level, we further detail the genes and transcription factors (TF) that determine the structural variability. The fly's olfactory receptor organs are the third antennal segments and the maxillary palps, which are covered with sensory hairs called sensilla. These sensilla house the odorant receptor neurons (ORNs) that express one or few odorant receptors in a stereotyped pattern regulated by combinations of TF. Also, perireceptor events, such as odor molecules transport to their receptors, are carried out by odorant binding proteins. In addition, the rapid odorant inactivation to preclude saturation of the system occurs by biotransformation and detoxification enzymes. These additional events take place in the lymph that surrounds the ORNs. We include some data on ionotropic and metabotropic olfactory transduction, although this issue is still under debate in Drosophila.

  13. Olfactory Ionotropic Receptors in Mosquito Aedes albopictus (Diptera: Culicidae).

    PubMed

    Chen, Qian; Man, Yahui; Li, Jianyong; Pei, Di; Wu, Wenjian

    2017-03-28

    Ionotropic glutamate receptors (iGluRs) are a conserved family of ligand-gated ion channels that primarily function to mediate neuronal communication at synapses. A variant subfamily of iGluRs, the ionotropic receptors (IRs), was recently identified in insects and proved with the function in odorant recognition. Ionotropic receptors participate in a distinct olfactory signaling pathway that is independent of olfactory receptors activity. In the present study, we identify 102 putative IR genes, dubbed as AalbIr genes, in mosquito Aedes albopictus (Skuse) by in silico comparative sequence analysis. Among AalbIr genes, 19 show expression in the female antenna by RT-PCR. These putative olfactory AalbIRs share four conservative hydrophobic domains of amino acids, similar to the transmembrane and ion channel pore regions found in conventional iGluRs. To determine the potential function of these olfactory AalbIRs in host-seeking, we compared their transcript expression levels in the antennae of blood-fed females with that of non-blood-fed females by quantitative real-time RT-PCR. Three AalbIr genes showed downregulation when the mosquito finished a bloodmeal. These results may help to improve our understanding of the IR-mediated olfactory signaling in mosquitoes.

  14. Correlation of cell surface proteins of distinct Beauveria bassiana cell types and adaption to varied environment and interaction with the host insect.

    PubMed

    Yang, Zhi; Jiang, Hongyan; Zhao, Xin; Lu, Zhuoyue; Luo, Zhibing; Li, Xuebing; Zhao, Jing; Zhang, Yongjun

    2017-02-01

    The insect fungal pathogen Beauveria bassiana produces a number of distinct cell types that include aerial conidia, blastospores and haemolymph-derived cells, termed hyphal bodies, to adapt varied environment niches and within the host insect. These cells display distinct biochemical properties and surface structures, and a highly ordered outermost brush-like structure uniquely present on hyphal bodies, but not on any in vitro cells. Here, we found that the outermost structure on the hyphal bodies mainly consisted of proteins associated to structural wall components in that most of it could be removed by dithiothreitol (DTT) or proteinase K. DTT-treatment also caused delayed germination, decreased tolerance to ultraviolet irradiation and virulence of conidia or blastospores, with decreased adherence and alternated carbohydrate epitopes, suggesting involvement in fungal development, stress responses and virulence. To characterize these cell surface molecules, proteins were released from the living cells using DTT, and identified and quantitated using label-free quantitative mass spectrometry. Thereafter, a series of bioinformatics programs were used to predict cell surface-associated proteins (CSAPs), and 96, 166 and 54 CSAPs were predicted from the identified protein pools of conidia, blastospores and hyphal bodies, respectively, which were involved in utilization of carbohydrate, nitrogen, and lipid, detoxification, pathogen-host interaction, and likely other cellular processes. Thirteen, sixty-nine and six CSAPs were exclusive in conidia, blastospores and hyphal bodies, respectively, which were verified by eGFP-tagged proteins at their N-terminus. Our data provide a crucial cue to understand mechanism of B. bassiana to adapt to varied environment and interaction with insect host.

  15. Identification and comparison of candidate odorant receptor genes in the olfactory and non-olfactory organs of Holotrichia oblita Faldermann by transcriptome analysis.

    PubMed

    Li, Kebin; Wei, Hongshuang; Shu, Changlong; Zhang, Shuai; Cao, Yazhong; Luo, Chen; Yin, Jiao

    2017-07-24

    A sophisticated olfactory system is part of the explanation for the prominence of insects among animals because of the essential roles of the olfactory system in foraging, host seeking, mating, ovipositing and avoiding toxic substances. In this study, we sequenced and analysed the transcriptomes of olfactory tissue (antennae) and non-olfactory tissue (legs) of the scarab beetle, Holotrichia oblita Faldermann, which is a serious underground pest in China. We obtained approximately 80.2 million 150bp reads that were assembled into 61,038 unigenes with an average length of 890bp. Among the transcripts, 70% of the unigenes were annotated. A total of 44 odorant receptors (ORs) and 9 ionotropic receptors (IRs) were identified based on homology searches. Then, quantitative real-time PCR experiments were performed to investigate the expression patterns of 32 putative chemosensory genes. The results showed that these genes were highly expressed in olfactory organs (antennae) and might play a key role in the olfaction-related behaviours in H. oblita. Based on the results of our phylogenetic analysis and the detailed tissue and sex-biased expression characteristics, the different roles of the receptor proteins in the olfactory system were also indicated. The results of this study will provide the foundation for further understanding of the olfactory odorant receptors of H. oblita at the molecular level and ultimately help to develop novel targets for manipulating this pest. Copyright © 2017. Published by Elsevier Inc.

  16. Olfactory toxicity in fishes.

    PubMed

    Tierney, Keith B; Baldwin, David H; Hara, Toshiaki J; Ross, Peter S; Scholz, Nathaniel L; Kennedy, Christopher J

    2010-01-21

    Olfaction conveys critical environmental information to fishes, enabling activities such as mating, locating food, discriminating kin, avoiding predators and homing. All of these behaviors can be impaired or lost as a result of exposure to toxic contaminants in surface waters. Historically, teleost olfaction studies have focused on behavioral responses to anthropogenic contaminants (e.g., avoidance). More recently, there has been a shift towards understanding the underlying mechanisms and functional significance of contaminant-mediated changes in fish olfaction. This includes a consideration of how contaminants affect the olfactory nervous system and, by extension, the downstream physiological and behavioral processes that together comprise a normal response to naturally occurring stimuli (e.g., reproductive priming or releasing pheromones). Numerous studies spanning several species have shown that ecologically relevant exposures to common pollutants such as metals and pesticides can interfere with fish olfaction and disrupt life history processes that determine individual survival and reproductive success. This represents one of the pathways by which toxic chemicals in aquatic habitats may increasingly contribute to the decline and at-risk status of many commercially and ecologically important fish stocks. Despite our emerging understanding of the threats that pollution poses for chemical communication in aquatic communities, many research challenges remain. These include: (1) the determination of specific mechanisms of toxicity in the fish olfactory sensory epithelium; (2) an understanding of the impacts of complex chemical mixtures; (3) the capacity to assess olfactory toxicity in fish in situ; (4) the impacts of toxins on olfactory-mediated behaviors that are still poorly understood for many fish species; and (5) the connections between sublethal effects on individual fish and the long-term viability of wild populations. This review summarizes and integrates

  17. Primary Events in Olfactory Reception

    DTIC Science & Technology

    1993-01-08

    sustentacular cells and Bowman’s glands and that it is deposited in the lower mucus layer of olfactory neuroepithelium. Next, we extracted mRNA from...protrude from the dendritic tips of olfactory receptor neurons. These cilia are surrounded by a layer of mucus that lines the olfactory...neuroepithelium. Odorants that enter the nasal cavity with the inspired air partition into and diffuse through this aqueous mucus layer on their way to odorant

  18. Insect Allergy.

    PubMed

    Lee, Hobart; Halverson, Sara; Mackey, Regina

    2016-09-01

    Insect bites and stings are common. Risk factors are mostly associated with environmental exposure. Most insect bites and stings result in mild, local, allergic reactions. Large local reactions and systemic reactions like anaphylaxis are possible. Common insects that bite or sting include mosquitoes, ticks, flies, fleas, biting midges, bees, and wasps. The diagnosis is made clinically. Identification of the insect should occur when possible. Management is usually supportive. For anaphylaxis, patients should be given epinephrine and transported to the emergency department for further evaluation. Venom immunotherapy (VIT) has several different protocols. VIT is highly effective in reducing systemic reactions and anaphylaxis.

  19. Do Native Insects and Associated Fungi Limit Non-Native Woodwasp, Sirex noctilio, Survival in a Newly Invaded Environment?

    PubMed Central

    Haavik, Laurel J.; Dodds, Kevin J.; Allison, Jeremy D.

    2015-01-01

    Sirex noctilio F. (Hymenoptera: Siricidae) is an introduced pest of pines (Pinus spp.) in several countries in the Southern Hemisphere. Although S. noctilio is established in North America (first discovered in 2004), it has not been a destructive pest there so far, where forest communities more closely resemble those in its native Eurasian range—where it is not a pest. To investigate the influence of the existing community of associated insects (competitors + natural enemies) and fungi (vectored by insects) on S. noctilio survival in North America, we examined stage-specific mortality factors and their relative importance, generating life tables drawn from experimentally-manipulated and natural cohorts of Sirex spp. (mostly S. noctilio, but some native S. nigricornis F.). For both natural and experimentally-manipulated cohorts, factors which acted during the earliest Sirex life stages, most likely tree resistance and/or competition among fungal associates, were paramount in dictating woodwasp survival. Experimentally-manipulated life tables revealed that protection from the community of associates resulted in a significantly, and substantially larger (>15x) S. noctilio F1 generation than exposure to it. Seventy percent of generation mortality in the exposed cohort was due to tree resistance or unknown causes early in larval development, which could have included competition among other bark- or wood-inhabiting insects and/or their fungal associates. Only 46% of generation mortality in the protected cohort was due to tree resistance and/or unknown causes. Parasitoids, particularly endoparasitoids (Ibalia spp.), showed limited ability to control S. noctilio, and reduced the experimentally-established cohort by only 11%, and natural cohorts an average of 3.4%. The relative importance of tree resistance vs. competition with bark- and wood-borers in reducing S. noctilio survival remains unclear. Tree resistance and/or competition likely contribute more than natural

  20. Do Native Insects and Associated Fungi Limit Non-Native Woodwasp, Sirex noctilio, Survival in a Newly Invaded Environment?

    PubMed

    Haavik, Laurel J; Dodds, Kevin J; Allison, Jeremy D

    2015-01-01

    Sirex noctilio F. (Hymenoptera: Siricidae) is an introduced pest of pines (Pinus spp.) in several countries in the Southern Hemisphere. Although S. noctilio is established in North America (first discovered in 2004), it has not been a destructive pest there so far, where forest communities more closely resemble those in its native Eurasian range—where it is not a pest. To investigate the influence of the existing community of associated insects (competitors + natural enemies) and fungi (vectored by insects) on S. noctilio survival in North America, we examined stage-specific mortality factors and their relative importance, generating life tables drawn from experimentally-manipulated and natural cohorts of Sirex spp. (mostly S. noctilio, but some native S. nigricornis F.). For both natural and experimentally-manipulated cohorts, factors which acted during the earliest Sirex life stages, most likely tree resistance and/or competition among fungal associates, were paramount in dictating woodwasp survival. Experimentally-manipulated life tables revealed that protection from the community of associates resulted in a significantly, and substantially larger (>15x) S. noctilio F1 generation than exposure to it. Seventy percent of generation mortality in the exposed cohort was due to tree resistance or unknown causes early in larval development, which could have included competition among other bark- or wood-inhabiting insects and/or their fungal associates. Only 46% of generation mortality in the protected cohort was due to tree resistance and/or unknown causes. Parasitoids, particularly endoparasitoids (Ibalia spp.), showed limited ability to control S. noctilio, and reduced the experimentally-established cohort by only 11%, and natural cohorts an average of 3.4%. The relative importance of tree resistance vs. competition with bark- and wood-borers in reducing S. noctilio survival remains unclear. Tree resistance and/or competition likely contribute more than natural

  1. Sildenafil affects olfactory function.

    PubMed

    Gudziol, V; Mück-Weymann, M; Seizinger, O; Rauh, R; Siffert, W; Hummel, T

    2007-01-01

    Sildenafil is the first member of a new class of oral drugs effective for erectile dysfunction. However, approximately 20% of patients complain about nasal congestion after sildenafil administration. Because nasal airflow and olfaction are closely linked, the sense of smell was evaluated in 20 young, healthy volunteers after the administration of 50 and 100 mg sildenafil, and placebo in a double-blinded, crossover study. Olfactory function was evaluated using a standardized and validated test (Sniffin' Sticks). To investigate a possible impact of G-protein beta3 subunit C825T polymorphism on the effect of sildenafil on olfaction the genotype of all subjects was determined. The effect of sildenafil on olfaction was only present at a dose of 100 mg but not at a dose of 50 mg sildenafil. The genotypes TT, CC and TC of the G-protein beta3 C825T polymorphism had no impact on the change in olfactory function. Higher sildenafil doses may produce decreased olfactory sensitivity.

  2. 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.

  3. 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.

  4. [Olfactory receptors and odour coding].

    PubMed

    Pernollet, Jean-Claude; Sanz, Guenhaël; Briand, Loïc

    2006-09-01

    The first step of olfactory detection involves interactions between odorant molecules and neuronal protein receptors. Odour coding results from the combinatory activation of a set of receptors and rests on their clonal expression and olfactory neurone connexion, which lead to formation of a specific sensory map in the cortex. This system, sufficient to discriminate myriads of odorants with a mere 350 different receptors, allows humans to smell molecules that are not natural (new cooking flavours, synthetic chemicals...). The extreme olfactory genome diversity explains the absence of odour semantics. Olfactory receptors are also involved in cellular chemotaxis.

  5. Evaluating insect-microbiomes at the plant-insect interface.

    PubMed

    Casteel, Clare L; Hansen, Allison K

    2014-07-01

    Plants recognize biotic challengers and respond with the appropriate defense by utilizing phytohormone signaling and crosstalk. Despite this, microbes and insects have evolved mechanisms that compromise the plant surveillance system and specific defenses, thus ensuring successful colonization. In nature, plants do not experience insect herbivores and microbes in isolation, but in combination. Over time, relationships have developed between insects and microbes, varying on a continuum from no-relationship to obligate relationships that are required for both organisms to survive. While many reviews have examined plant-insect and plant-microbe interactions and the mechanisms of plant defense, few have considered the interface where microbes and insects may overlap, and synergies may develop. In this review, we critically evaluate the requirements for insect-associated microbes to develop synergistic relationships with their hosts, and we mechanistically discuss how some of these insect-associated microbes can target or modify host plant defenses. Finally, by using bioinformatics and the recent literature, we review evidence for synergies in insect-microbe relationships at the interface of plant-insect defenses. Insect-associated microbes can influence host-plant detection and/or signaling through phytohormone synthesis, conserved microbial patterns, and effectors, however, microbes associated with insects must be maintained in the environment and located in opportunistic positions.

  6. An insect gut environment reveals the induction of a new sugar-phosphate sensor system in Bacillus cereus

    PubMed Central

    Song, Fuping; Peng, Qi; Brillard, Julien; Lereclus, Didier; Nielsen-LeRoux, Christina

    2014-01-01

    Bacteria survive under various conditions by sensing stimuli triggering specific adaptive physiological responses, which are often based on membrane-integrated sensors connected to a cytoplasmic regulator. Recent studies reveal that mucus glycans may act as signal molecules for two-component systems involved in intestinal colonization. Bacillus cereus, a human and insect opportunistic pathogen was used to identify bacterial factors expressed in an insect gut infection model. The screen revealed a promoter involved in the expression of a gene with so far unknown functions. A search for gut-related compounds, inducing its transcription, identified glucose-6-phosphate as an activation signal. The gene is part of a five-gene cluster, including a two-component system. Interestingly such five gene loci are conserved in the pathogenic Bacillus group as well as in various Clostridia bacteria and are with analogy to other multi-component sensor systems in enteropathogenic bacteria, such as E. coli. Thus our results provide insights into the function of two-component and auxiliary sensor systems in host-microbe interactions and opens up possible investigations of such systems in other gut associated bacteria. PMID:24256737

  7. An insect gut environment reveals the induction of a new sugar-phosphate sensor system in Bacillus cereus.

    PubMed

    Song, Fuping; Peng, Qi; Brillard, Julien; Lereclus, Didier; Nielsen-LeRoux, Christina

    2014-01-01

    Bacteria survive under various conditions by sensing stimuli triggering specific adaptive physiological responses, which are often based on membrane-integrated sensors connected to a cytoplasmic regulator. Recent studies reveal that mucus glycans may act as signal molecules for two-component systems involved in intestinal colonization. Bacillus cereus, a human and insect opportunistic pathogen was used to identify bacterial factors expressed in an insect gut infection model. The screen revealed a promoter involved in the expression of a gene with so far unknown functions. A search for gut-related compounds, inducing its transcription, identified glucose-6-phosphate as an activation signal. The gene is part of a five-gene cluster, including a two-component system. Interestingly such five gene loci are conserved in the pathogenic Bacillus group as well as in various Clostridia bacteria and are with analogy to other multi-component sensor systems in enteropathogenic bacteria, such as E. coli. Thus our results provide insights into the function of two-component and auxiliary sensor systems in host-microbe interactions and opens up possible investigations of such systems in other gut associated bacteria.

  8. Recovery of olfactory function after bilateral bulbectomy.

    PubMed

    Wright, J W; Harding, J W

    1982-04-16

    Mice were trained to discriminate between scented and unscented air. After olfactory bulbs were removed, discrimination was lost, but returned with the formation of synaptic connections between regenerated primary olfactory neurons and the cortex of the forebrain. The acquisition of a second olfactory-mediated task by long-term bulbectomized mice and controls was indistinguishable. The results emphasize the plasticity of the nervous system, correlate the presence of neural connections between olfactory mucosa and forebrain with the recovery of olfactory function, suggest that olfactory-mediated memory resides at least in part outside the olfactory bulbs, and demonstrate that the bulbs are not required for the acquisition of olfactory tasks.

  9. Innovations: applications of insect transgenesis.

    PubMed

    Wimmer, Ernst A

    2003-03-01

    The recent establishment of broadly applicable genetic transformation systems will allow the analysis of gene function in diverse insect species. This will increase our understanding of developmental and evolutionary biology. Furthermore, insect transgenesis will provide new strategies for insect pest management and methods to impair the transmission of pathogens by human disease vectors. However, these powerful techniques must be applied with great care to avoid harm to our environment.

  10. Insect Keepers

    ERIC Educational Resources Information Center

    Moore, Virginia J.; Chessin, Debby A.; Theobald, Becky

    2010-01-01

    Insects are fascinating creatures--especially when you and your students get up close and personal with them! To that end, the authors facilitated an inquiry-based investigation with an emphasis on identification of the different types of insects found in the school yard, their characteristics, their habitat, and what they eat, while engaging the…

  11. III. Insects

    Treesearch

    Jose F. Negron

    2011-01-01

    RMRS research on insect pests focuses mostly on conifer pests. There is a long history of invasive insects causing significant impacts, mortality, and changes in forest ecosystem structure in North America. Perhaps the most evident example is the introduction of the gypsy moth, Lymantria dispar, into eastern North America in the 1860s (Forbush and Frenald 1896)....

  12. Insect Keepers

    ERIC Educational Resources Information Center

    Moore, Virginia J.; Chessin, Debby A.; Theobald, Becky

    2010-01-01

    Insects are fascinating creatures--especially when you and your students get up close and personal with them! To that end, the authors facilitated an inquiry-based investigation with an emphasis on identification of the different types of insects found in the school yard, their characteristics, their habitat, and what they eat, while engaging the…

  13. Insect phylogenomics.

    PubMed

    Behura, S K

    2015-08-01

    Phylogenomics, the integration of phylogenetics with genome data, has emerged as a powerful approach to study the evolution and systematics of species. Recently, several studies employing phylogenomic tools have provided better insights into insect evolution. Next-generation sequencing methods are now increasingly used by entomologists to generate genomic and transcript sequences of various insect species and strains. These data provide opportunities for comparative genomics and large-scale multigene phylogenies of diverse lineages of insects. Phy-logenomic investigations help us to better understand systematic and evolutionary relationships of insect species that play important roles as herbivores, predators, detritivores, pollinators and disease vectors. It is important that we critically assess the prospects and limitations of phylogenomic methods. In this review, I describe the current status, outline the major challenges and remark on potential future applications of phylogenomic tools in studying insect systematics and evolution. © 2015 The Royal Entomological Society.

  14. Selectivity of odorant receptors in insects

    PubMed Central

    Bohbot, Jonathan D.; Dickens, Joseph C.

    2012-01-01

    Insect olfactory receptors (ORs) detect chemicals, shape neuronal physiology, and regulate behavior. Although ORs have been categorized as “generalists” and “specialists” based on their ligand spectrum, both electrophysiological studies and recent pharmacological investigations show that ORs specifically recognize non-pheromonal compounds, and that our understanding of odorant-selectivity mirrors our knowledge of insect chemical ecology. As we are progressively becoming aware that ORs are activated through a variety of mechanisms, the molecular basis of odorant-selectivity and the corollary notion of broad-tuning need to be re-examined from a pharmacological and evolutionary perspective. PMID:22811659

  15. Olfactory dysfunction and daily life.

    PubMed

    Frasnelli, Johannes; Hummel, Thomas

    2005-03-01

    The objective of the present study was to investigate the hypothesis that subjects with parosmia suffer more in their daily life than patients who experience only quantitative olfactory loss. Two hundred five outpatients of the Smell and Taste Clinic and 25 healthy controls were included. The newly developed Questionnaire of Olfactory Disorders (QOD) was administered in combination with other psychometric tests (Beck Depression Inventory, "Befindlichkeitsskala" and the Short Form-36 Health Survey) along with an olfactory test ("Sniffin' Sticks"). Results of the QOD were found to be an appropriate and valid measure of the impact of olfactory dysfunction on daily life. Patients with parosmia and quantitative olfactory dysfunction show higher rates of daily life complaints when compared to patients suffering from quantitative olfactory impairment only (QOD-PS: P=0.005). In addition, hyposmic and anosmic patients indicated significantly more complaints compared to patients with normosmia. Further, female patients seemed to suffer more from olfactory dysfunction than male patients. In conclusion, the assessment of the degree of qualitative olfactory dysfunction may be possible by the use of instruments based on questionnaires regarding daily life problems.

  16. Determinants of human olfactory performance: a cross-cultural study.

    PubMed

    Sorokowska, Agnieszka; Sorokowski, Piotr; Frackowiak, Tomasz

    2015-02-15

    Olfaction allows us to detect subtle changes in our environment, but sensitivity of the sense of smell varies among individuals. Although a significant number of research papers discuss the relationship between olfactory abilities and environmental factors, most studies have been conducted on Western populations or in developed Asian societies. The potential environmental and cultural determinants of olfactory acuity warrant further exploration. In the current study, we compared previously published data on olfaction in an industrialized, modern society (i.e., Europeans) and an indigenous society living in unpolluted, natural environmental conditions (i.e., Tsimane'), with novel data on the olfactory acuity of inhabitants of the Cook Islands. Like the European population (and contrary to the Tsimane'), the Cook Islands people form a modern society, and like the Tsimane' population (and contrary to the Europeans), they live in an unpolluted region. Thus, these comparisons enabled us to independently assess the importance of both air pollution and changes in lifestyle for olfactory abilities in modern societies. Our results indicate that people from the Cook Islands had significantly higher olfactory acuity (i.e., lower thresholds of odor detection) than did Europeans and Tsimane' people. Interestingly, the olfactory sensitivity of Europeans was significantly lower than the olfactory sensitivity of the remaining two groups. Our data suggest that air pollution is an important factor in the deterioration of the sense of smell. However, it is also possible that factors such as agricultural and/or cooking practices, alcohol consumption, and access to medical service may also influence olfactory acuity. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Invertebrate learning and memory: Fifty years of olfactory conditioning of the proboscis extension response in honeybees.

    PubMed

    Giurfa, Martin; Sandoz, Jean-Christophe

    2012-02-01

    The honeybee Apis mellifera has emerged as a robust and influential model for the study of classical conditioning, thanks to the existence of a powerful Pavlovian conditioning protocol, the olfactory conditioning of the proboscis extension response (PER). In 2011, the olfactory PER conditioning protocol celebrates 50 years since it was first introduced by Kimihisa Takeda in 1961. Here, we review its origins, developments, and perspectives in order to define future research avenues and necessary methodological and conceptual evolutions. We show that olfactory PER conditioning has become a versatile tool for the study of questions in extremely diverse fields in addition to the study of learning and memory and that it has allowed behavioral characterizations, not only of honeybees, but also of other insect species, for which the protocol was adapted. We celebrate, therefore, Takeda's original work and prompt colleagues to conceive and establish further robust behavioral tools for an accurate characterization of insect learning and memory at multiple levels of analysis.

  18. 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.

  19. Olfactory illusions: where are they?

    PubMed

    Stevenson, Richard J

    2011-12-01

    It has been suggested that there maybe no olfactory illusions. This manuscript examines this claim and argues that it arises because olfactory illusions are not typically accompanied by an awareness of their illusory nature. To demonstrate that olfactory illusions do occur, the relevant empirical literature is reviewed, by examining instances of where the same stimulus results in different percepts, and of where different stimuli result in the same percept. The final part of the manuscript evaluates the evidence favoring the existence of olfactory illusions, and then examines why they may not typically be accompanied by awareness. Three contributory mechanisms are discussed, relating to difficulty of verification and paucity of olfactory knowledge, the role of change blindness, and restricted access consciousness in this sense.

  20. Effects of Caffeine on Olfactory Learning in Crickets.

    PubMed

    Sugimachi, Seigo; Matsumoto, Yukihisa; Mizunami, Makoto; Okada, Jiro

    2016-10-01

    Caffeine is a plant-derived alkaloid that is generally known as a central nervous system (CNS) stimulant. In order to examine the effects of caffeine on higher CNS functions in insects, we used an appetitive olfactory learning paradigm for the cricket Gryllus bimaculatus. Crickets can form significant long-term memories (LTMs) after repetitive training sessions, during which they associate a conditioned stimulus (CS: odor) with an unconditioned stimulus (US: reward). Administration of hemolymphal injections of caffeine established LTM after only single-trial conditioning over a wide range of caffeine dosages (1.6 µµg/kg to 39 mg/kg). We investigated the physiological mechanisms underlying this enhancement of olfactory learning performance pharmacologically, focusing on three major physiological roles of caffeine: 1) inhibition of phosphodiesterase (PDE), 2) agonism of ryanodine receptors, and 3) antagonism of adenosine receptors. Application of drugs relevant to these actions resulted in significant effects on LTM formation. These results suggest that externally applied caffeine enhances LTM formation in insect olfactory learning via multiple cellular mechanisms.

  1. Neurophysiological and behavioral responses of gypsy moth larvae to insect repellents

    USDA-ARS?s Scientific Manuscript database

    The interactions between insect repellents and the olfactory system have been widely studied, however relatively little is known about the effects of repellents on the gustatory system of insects. In this study, we show that the gustatory receptor neuron (GRN) located in the medial styloconic sensi...

  2. A Robust Feedforward Model of the Olfactory System

    PubMed Central

    Zhang, Yilun; Sharpee, Tatyana O.

    2016-01-01

    Most natural odors have sparse molecular composition. This makes the principles of compressed sensing potentially relevant to the structure of the olfactory code. Yet, the largely feedforward organization of the olfactory system precludes reconstruction using standard compressed sensing algorithms. To resolve this problem, recent theoretical work has shown that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. However, the dynamical aspects of optimization slowed down odor recognition and were also found to be susceptible to noise. Here we describe a feedforward model of the olfactory system that achieves both strong compression and fast reconstruction that is also robust to noise. A key feature of the proposed model is a specific relationship between how odors are represented at the glomeruli stage, which corresponds to a compression, and the connections from glomeruli to third-order neurons (neurons in the olfactory cortex of vertebrates or Kenyon cells in the mushroom body of insects), which in the model corresponds to reconstruction. We show that should this specific relationship hold true, the reconstruction will be both fast and robust to noise, and in particular to the false activation of glomeruli. The predicted connectivity rate from glomeruli to third-order neurons can be tested experimentally. PMID:27065441

  3. Neurally Encoding Time for Olfactory Navigation

    PubMed Central

    Park, In Jun; Hein, Andrew M.; Bobkov, Yuriy V.; Reidenbach, Matthew A.; Ache, Barry W.; Principe, Jose C.

    2016-01-01

    Accurately encoding time is one of the fundamental challenges faced by the nervous system in mediating behavior. We recently reported that some animals have a specialized population of rhythmically active neurons in their olfactory organs with the potential to peripherally encode temporal information about odor encounters. If these neurons do indeed encode the timing of odor arrivals, it should be possible to demonstrate that this capacity has some functional significance. Here we show how this sensory input can profoundly influence an animal’s ability to locate the source of odor cues in realistic turbulent environments—a common task faced by species that rely on olfactory cues for navigation. Using detailed data from a turbulent plume created in the laboratory, we reconstruct the spatiotemporal behavior of a real odor field. We use recurrence theory to show that information about position relative to the source of the odor plume is embedded in the timing between odor pulses. Then, using a parameterized computational model, we show how an animal can use populations of rhythmically active neurons to capture and encode this temporal information in real time, and use it to efficiently navigate to an odor source. Our results demonstrate that the capacity to accurately encode temporal information about sensory cues may be crucial for efficient olfactory navigation. More generally, our results suggest a mechanism for extracting and encoding temporal information from the sensory environment that could have broad utility for neural information processing. PMID:26730727

  4. Is there a risk associated with the insect repellent DEET (N,N-diethyl-m-toluamide) commonly found in aquatic environments?

    USGS Publications Warehouse

    Costanzo, S.D.; Watkinson, A.J.; Murby, E.J.; Kolpin, D.W.; Sandstrom, M.W.

    2007-01-01

    DEET (N,N-diethyl-m-toluamide) is the active ingredient of most commercial insect repellents. This compound has commonly been detected in aquatic water samples from around the world indicating that DEET is both mobile and persistent, despite earlier assumptions that DEET was unlikely to enter aquatic ecosystems. DEET's registration category does not require an ecological risk assessment, thus information on the ecological toxicity of DEET is sparse. This paper reviews the presence of DEET in aqueous samples from around the world (e.g. drinking water, streams, open seawater, groundwater and treated effluent) with reported DEET concentrations ranging from 40–3000 ng L− 1. In addition, new DEET data collected from 36 sites in coastal waterways from eastern Australia (detections ranging from 8 to 1500 ng L− 1) are examined. A summary of new and existing toxicity data are discussed with an emphasis on preparing a preliminary risk assessment for DEET in the aquatic environment. Collated information on DEET in the aquatic environment suggests risk to aquatic biota at observed environmental concentrations is minimal. However, the information available was not sufficient to conduct a full risk assessment due to data deficiencies in source characterisation, transport mechanisms, fate, and ecotoxicity studies. These risks warrant further investigation due to the high frequency that this organic contaminant is detected in aquatic environments around the world.

  5. Detection and discrimination of mixed odor strands in overlapping plumes using an insect-antenna-based chemosensor system.

    PubMed

    Myrick, Andrew J; Park, Kye Chung; Hetling, John R; Baker, Thomas C

    2009-01-01

    Olfactory signals, a major means of communication in insects, travel in the form of turbulent odor plumes. In terrestrial environments, an odor blend emitted from a single point source exists in every strand of the plume, whereas, in confluent plumes from two different odor sources, the strands have some chance of being coincident and comprising a new third odor in those strands. Insects have the ability to detect and interpret necessary olfactory information from individual filamentous odor strands in complex multifilament odor plumes. However, behaviorists have had no way to measure the stimulus situations they are presenting to their temporally acute insect subjects when performing Y-tube olfactometer or confluent pheromone plume wind tunnel assays. We have successfully measured the degree of plume-strand mixing in confluent plumes in a wind tunnel by using a multichannel insect-antenna-based chemosensor. A PC-based computer algorithm to analyze antennal signals from the probe portion of the system performed real-time signal processing and, following a short training session, classified individual odorant/mixture strands at sub-second temporal resolution and a few tens of millimeters of spatial resolution. In our studies, the chemosensor classified a higher frequency of strands of two different odorants emitted from two closely spaced filter papers as being "mixed" when the sources were located only 1 or 2 cm apart than when the sources were 5 or 10 cm apart. These experiments demonstrate the chemosensor's potential to be used for measuring odor stimulus situations in more complex multiple-plume environments.

  6. Effects of starvation on the olfactory responses of the blood-sucking bug Rhodnius prolixus.

    PubMed

    Reisenman, Carolina E; Lee, Yan; Gregory, Teresa; Guerenstein, Pablo G

    2013-07-01

    Blood-sucking insects use olfactory cues in a variety of behavioral contexts, including host-seeking and aggregation. In triatomines, which are obligated blood-feeders, it has been shown that the response to CO2, a host-associated olfactory cue used almost universally by blood-sucking insects, is modulated by hunger. Host-finding is a particularly dangerous task for these insects, as their hosts are also their potential predators. Here we investigated whether olfactory responses to host-derived volatiles other than CO2 (nonanal, α-pinene and (-)-limonene), attractive odorant mixtures (yeast volatiles), and aggregation pheromones (present in feces) are also modulated by starvation in the blood-sucking bug Rhodnius prolixus. For this, the responses of both non-starved and starved insects were individually tested at the beginning of the scotophase using a dual-choice "T-shaped" olfactometer, in which one of its arms presented odor-laden air and the other arm presented odorless air. We found that the response of non-starved insects toward host-odorants and odorant mixtures was odor-dependent: insects preferred the odor-laden arm of the maze when tested with α-pinene, the odorless arm of the maze when tested with (-)-limonene, and distributed at random when tested with yeast volatiles or nonanal. In contrast, starved insects significantly preferred the odor-laden arm of the maze when tested with host-odorants or yeast volatiles. When tested with aggregation be, while starved insects preferred the odorless arm of the maze; insects that were even more starved (8-9 weeks post-ecdysis) significantly preferred the odor-laden arm of the maze. We postulate that this odor- and starvation-dependent modulation of sensory responses has a high adaptive value, as it minimizes the costs and risks associated with the associated behaviors. The possible physiological mechanisms underlying these modulatory effects are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Organization of the olfactory system of nymphalidae butterflies.

    PubMed

    Carlsson, Mikael A; Schäpers, Alexander; Nässel, Dick R; Janz, Niklas

    2013-05-01

    Olfaction is in many species the most important sense, essential for food search, mate finding, and predator avoidance. Butterflies have been considered a microsmatic group of insects that mainly rely on vision due to their diurnal lifestyle. However, an emerging number of studies indicate that butterflies indeed use the sense of smell for locating food and oviposition sites. To unravel the neural substrates for olfaction, we performed an anatomical study of 2 related butterfly species that differ in food and host plant preference. We found many of the anatomical structures and pathways, as well as distribution of neuroactive substances, to resemble that of their nocturnal relatives among the Lepidoptera. The 2 species differed in the number of one type of olfactory sensilla, thus indicating a difference in sensitivity to certain compounds. Otherwise no differences could be observed. Our findings suggest that the olfactory system in Lepidoptera is well conserved despite the long evolutionary time since butterflies and moths diverged from a common ancestor.

  8. Insect Repellents: Reducing Insect Bites

    MedlinePlus

    ... What is an insect repellent? Disease risk from mosquito and tick bites Ingredients in skin-applied repellents ... and Blogs Using Repellent Products to Protect against Mosquito-Borne Illnesses Federal Trade Commission Action on Deceptive ...

  9. Odor-Specific, Olfactory Marker Protein-Mediated Sparsening of Primary Olfactory Input to the Brain after Odor Exposure

    PubMed Central

    Kass, Marley D.; Moberly, Andrew H.; Rosenthal, Michelle C.; Guang, Stephanie A.

    2013-01-01

    Long-term plasticity in sensory systems is usually conceptualized as changing the interpretation of the brain of sensory information, not an alteration of how the sensor itself responds to external stimuli. However, here we demonstrate that, in the adult mouse olfactory system, a 1-week-long exposure to an artificially odorized environment narrows the range of odorants that can induce neurotransmitter release from olfactory sensory neurons (OSNs) and reduces the total transmitter release from responsive neurons. In animals heterozygous for the olfactory marker protein (OMP), this adaptive plasticity was strongest in the populations of OSNs that originally responded to the exposure odorant (an ester) and also observed in the responses to a similar odorant (another ester) but had no effect on the responses to odorants dissimilar to the exposure odorant (a ketone and an aldehyde). In contrast, in OMP knock-out mice, odorant exposure reduced the number and amplitude of OSN responses evoked by all four types of odorants equally. The effect of this plasticity is to preferentially sparsen the primary neural representations of common olfactory stimuli, which has the computational benefit of increasing the number of distinct sensory patterns that could be represented in the circuit and might thus underlie the improvements in olfactory discrimination often observed after odorant exposure (Mandairon et al., 2006a). The absence of odorant specificity in this adaptive plasticity in OMP knock-out mice suggests a potential role for this protein in adaptively reshaping OSN responses to function in different environments. PMID:23575856

  10. 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.

  11. Olfactory receptor gene expression in tiger salamander olfactory epithelium.

    PubMed

    Marchand, James E; Yang, Xinhai; Chikaraishi, Dona; Krieger, Jurgen; Breer, Heinz; Kauer, John S

    2004-06-28

    Physiological studies of odor-elicited responses from the olfactory epithelium and bulb in the tiger salamander, Ambystoma tigrinum, have elucidated a number of features of olfactory coding that appear to be conserved across several vertebrate species. This animal model has provided an accessible in vivo system for observing individual and ensemble olfactory responses to odorant stimulation using biochemical, neurophysiological, and behavioral assays. In this paper we have complemented these studies by characterizing 35 candidate odorant receptor genes. These receptor sequences are similar to those of the large families of olfactory receptors found in mammals and fish. In situ hybridization, using RNA probes to 20 of these sequences, demonstrates differential distributions of labeled cells across the extent and within the depth of the olfactory epithelium. The distributions of cells labeled with probes to different receptors show spatially restricted patterns that are generally localized to different degrees in medial-lateral and anterior-posterior directions. The patterns of receptor expression in the ventral olfactory epithelium (OE) are mirrored in the dorsal OE. We present a hypothesis as to how the sensory neuron populations expressing different receptor types responding to a particular odorant may relate to the distribution patterns of epithelial and bulbar responses previously characterized using single-unit and voltage-sensitive dye recording methods. Copyright 2004 Wiley-Liss, Inc.

  12. Insect Phylogenomics

    PubMed Central

    Behura, Susanta K.

    2015-01-01

    With the advent of next-generation sequencing methods, phylogenetics has taken a new turn in the recent years. Phylogenomics, the integration of phylogenetics with genome data, has emerged as a powerful approach to study systematics and evolution of species. Recently, breakthrough researches employing phylogenomic tools have provided better insights into the timing and pattern of insect evolution. The next-generation sequencing methods are now increasingly used by entomologists to generate genomic and transcript sequences of various insect species and strains. These data provide opportunities for comparative genomics and large-scale multigene phylogenies of diverse lineages of insects. Phylogenomic investigations help us better understand systematic and evolutionary relationships of insect species that play important roles as herbivores, predators, detritivores, pollinators, or disease vectors. It is important that we critically assess the prospects and limitations of phylogenomic methods. In this review, I describe the current status, outline the major challenges, and remark on potential future applications of phylogenomic tools in studying insect systematics and evolution. PMID:25963452

  13. Inhibition among olfactory receptor neurons

    PubMed Central

    Van der Goes van Naters, Wynand

    2013-01-01

    Often assumed to be epiphenomena of a cell’s activity, extracellular currents and resulting potential changes are increasingly recognized to influence the function of other cells in the vicinity. Experimental evidence shows that even small electric fields can modulate spike timing in neurons. Moreover, when neurons are brought close together experimentally or in pathological conditions, activity in one neuron can excite its neighbors. Inhibitory ephaptic mechanisms, however, may depend on more specialized coupling among cells. Recent studies in the Drosophila olfactory system have shown that excitation of a sensory neuron can inhibit its neighbor, and it was speculated that this interaction was ephaptic. Here we give an overview of ephaptic interactions that effect changes in spike timing, excitation or inhibition in diverse systems with potential relevance to human neuroscience. We examine the mechanism of the inhibitory interaction in the Drosophila system and that of the well-studied ephaptic inhibition of the Mauthner cell in more detail. We note that both current towards and current away from the local extracellular environment of a neuron can inhibit it, but the mechanism depends on the specific architecture of each system. PMID:24167484

  14. 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

  15. Brain organization and the origin of insects: an assessment

    PubMed Central

    Strausfeld, Nicholas James

    2009-01-01

    Within the Arthropoda, morphologies of neurons, the organization of neurons within neuropils and the occurrence of neuropils can be highly conserved and provide robust characters for phylogenetic analyses. The present paper reviews some features of insect and crustacean brains that speak against an entomostracan origin of the insects, contrary to received opinion. Neural organization in brain centres, comprising olfactory pathways, optic lobes and a central neuropil that is thought to play a cardinal role in multi-joint movement, support affinities between insects and malacostracan crustaceans. PMID:19324805

  16. Context-Dependent Olfactory Learning in an Insect

    ERIC Educational Resources Information Center

    Matsumoto, Yukihisa; Mizunami, Makoto

    2004-01-01

    We studied the capability of the cricket "Gryllus bimaculatus" to select one of a pair of odors and to avoid the other in one context and to do the opposite in another context. One group of crickets was trained to associate one of a pair of odors (conditioned stimulus, CS1) with water reward (appetitive unconditioned stimulus, US+) and another…

  17. Context-Dependent Olfactory Learning in an Insect

    ERIC Educational Resources Information Center

    Matsumoto, Yukihisa; Mizunami, Makoto

    2004-01-01

    We studied the capability of the cricket "Gryllus bimaculatus" to select one of a pair of odors and to avoid the other in one context and to do the opposite in another context. One group of crickets was trained to associate one of a pair of odors (conditioned stimulus, CS1) with water reward (appetitive unconditioned stimulus, US+) and another…

  18. Functional conservation of an insect odorant receptor gene across 250 million years of evolution.

    PubMed

    Jones, Walton D; Nguyen, Thuy-Ai T; Kloss, Brian; Lee, Kevin J; Vosshall, Leslie B

    2005-02-22

    Pest insects have a profound negative impact on agriculture and human health. Significant global losses of crops, stored agricultural products, timber and livestock can be attributed to damage and destruction by insects . Blood-feeding insects such as mosquitoes, flies and ticks transmit many of humanity's most devastating infectious diseases. Insect-borne diseases account for more than one million annual fatalities, and insect-associated illnesses surpass 300 million annual reported cases . The medical and economic impact of these animals can be ascribed in part to the sensitivity and selectivity of their olfactory systems, essential for location of their preferred plant and animal hosts.

  19. Antennal lobe representations are optimized when olfactory stimuli are periodically structured to simulate natural wing beat effects

    PubMed Central

    Houot, Benjamin; Burkland, Rex; Tripathy, Shreejoy; Daly, Kevin C.

    2014-01-01

    Animals use behaviors to actively sample the environment across a broad spectrum of sensory domains. These behaviors discretize the sensory experience into unique spatiotemporal moments, minimize sensory adaptation, and enhance perception. In olfaction, behaviors such as sniffing, antennal flicking, and wing beating all act to periodically expose olfactory epithelium. In mammals, it is thought that sniffing enhances neural representations; however, the effects of insect wing beating on representations remain unknown. To determine how well the antennal lobe (AL) produces odor dependent representations when wing beating effects are simulated, we used extracellular methods to record neural units and local field potentials (LFPs) from moth AL. We recorded responses to odors presented as prolonged continuous stimuli or periodically as 20 and 25 Hz pulse trains designed to simulate the oscillating effects of wing beating around the antennae during odor guided flight. Using spectral analyses, we show that ~25% of all recorded units were able to entrain to “pulsed stimuli”; this includes pulsed blanks, which elicited the strongest overall entrainment. The strength of entrainment to pulse train stimuli was dependent on molecular features of the odorants, odor concentration, and pulse train duration. Moreover, units showing pulse tracking responses were highly phase locked to LFPs during odor stimulation, indicating that unit-LFP phase relationships are stimulus-driven. Finally, a Euclidean distance-based population vector analysis established that AL odor representations are more robust, peak more quickly, and do not show adaptation when odors were presented at the natural wing beat frequency as opposed to prolonged continuous stimulation. These results suggest a general strategy for optimizing olfactory representations, which exploits the natural rhythmicity of wing beating by integrating mechanosensory and olfactory cues at the level of the AL. PMID:24971052

  20. Olfactory dysfunction in Parkinson's disease.

    PubMed

    Hawkes, C H; Shephard, B C; Daniel, S E

    1997-05-01

    To evaluate olfactory function in Parkinson's disease. A standardised odour identification test was used, together with an evoked potential assessment with hydrogen sulphide. In addition, histological analysis was performed on the olfactory bulbs of cadavers who died from Parkinson's disease. Over 70% of patients studied (71 of 96) were outside the 95% limit of normal on the identification test in an age matched sample and there was an unusual pattern of selective loss to certain odours, not hitherto described. The evoked potentials were significantly delayed but of comparable amplitude to a control matched population. Of the 73 patients studied only 37 had a technically satisfactory record containing a clear response to both gases and of these, 12 were delayed. For H2S there was more delay on stimulating the right nostril than the left. Some patients with normal smell identification test scores had delayed evoked potentials. In the pathological examination of olfactory bulbs from eight brains, changes characteristic of Parkinson's disease (Lewy bodies) were seen in every olfactory bulb, particularly in the anterior olfactory nucleus, and were sufficiently distinct to allow a presumptive diagnosis of Parkinson's disease. Olfactory damage in Parkinson's disease is consistent and severe and may provide an important clue to the aetiology of the disease.

  1. Olfactory dysfunction in Parkinson's disease.

    PubMed Central

    Hawkes, C H; Shephard, B C; Daniel, S E

    1997-01-01

    OBJECTIVE: To evaluate olfactory function in Parkinson's disease. METHODS: A standardised odour identification test was used, together with an evoked potential assessment with hydrogen sulphide. In addition, histological analysis was performed on the olfactory bulbs of cadavers who died from Parkinson's disease. RESULTS: Over 70% of patients studied (71 of 96) were outside the 95% limit of normal on the identification test in an age matched sample and there was an unusual pattern of selective loss to certain odours, not hitherto described. The evoked potentials were significantly delayed but of comparable amplitude to a control matched population. Of the 73 patients studied only 37 had a technically satisfactory record containing a clear response to both gases and of these, 12 were delayed. For H2S there was more delay on stimulating the right nostril than the left. Some patients with normal smell identification test scores had delayed evoked potentials. In the pathological examination of olfactory bulbs from eight brains, changes characteristic of Parkinson's disease (Lewy bodies) were seen in every olfactory bulb, particularly in the anterior olfactory nucleus, and were sufficiently distinct to allow a presumptive diagnosis of Parkinson's disease. CONCLUSIONS: Olfactory damage in Parkinson's disease is consistent and severe and may provide an important clue to the aetiology of the disease. Images PMID:9153598

  2. Nutrient Sensing: Another Chemosensitivity of the Olfactory System

    PubMed Central

    Julliard, A-Karyn; Al Koborssy, Dolly; Fadool, Debra A.; Palouzier-Paulignan, Brigitte

    2017-01-01

    Olfaction is a major sensory modality involved in real time perception of the chemical composition of the external environment. Olfaction favors anticipation and rapid adaptation of behavioral responses necessary for animal survival. Furthermore, recent studies have demonstrated that there is a direct action of metabolic peptides on the olfactory network. Orexigenic peptides such as ghrelin and orexin increase olfactory sensitivity, which in turn, is decreased by anorexigenic hormones such as insulin and leptin. In addition to peptides, nutrients can play a key role on neuronal activity. Very little is known about nutrient sensing in olfactory areas. Nutrients, such as carbohydrates, amino acids, and lipids, could play a key role in modulating olfactory sensitivity to adjust feeding behavior according to metabolic need. Here we summarize recent findings on nutrient-sensing neurons in olfactory areas and delineate the limits of our knowledge on this topic. The present review opens new lines of investigations on the relationship between olfaction and food intake, which could contribute to determining the etiology of metabolic disorders. PMID:28747887

  3. Disruption of Aedes aegypti Olfactory System Development through Chitosan/siRNA Nanoparticle Targeting of semaphorin-1a

    PubMed Central

    Mysore, Keshava; Flannery, Ellen M.; Tomchaney, Michael; Severson, David W.; Duman-Scheel, Molly

    2013-01-01

    Despite the devastating impact of mosquito-borne illnesses on human health, surprisingly little is known about mosquito developmental biology, including development of the olfactory system, a tissue of vector importance. Analysis of mosquito olfactory developmental genetics has been hindered by a lack of means to target specific genes during the development of this sensory system. In this investigation, chitosan/siRNA nanoparticles were used to target semaphorin-1a (sema1a) during olfactory system development in the dengue and yellow fever vector mosquito Aedes aegypti. Immunohistochemical analyses and anterograde tracing of antennal sensory neurons, which were used to track the progression of olfactory development in this species, revealed antennal lobe defects in sema1a knockdown fourth instar larvae. These findings, which correlated with a larval odorant tracking behavioral phenotype, identified previously unreported roles for Sema1a in the developing insect larval olfactory system. Analysis of sema1a knockdown pupae also revealed a number of olfactory phenotypes, including olfactory receptor neuron targeting and projection neuron defects coincident with a collapse in the structure and shape of the antennal lobe and individual glomeruli. This study, which is to our knowledge the first functional genetic analysis of insect olfactory development outside of D. melanogaster, identified critical roles for Sema1a during Ae. aegypti larval and pupal olfactory development and advocates the use of chitosan/siRNA nanoparticles as an effective means of targeting genes during post-embryonic Ae. aegypti development. Use of siRNA nanoparticle methodology to understand sensory developmental genetics in mosquitoes will provide insight into the evolutionary conservation and divergence of key developmental genes which could be exploited in the development of both common and species-specific means for intervention. PMID:23696908

  4. Pre-birth sense of smell in the wild boar: the ontogeny of the olfactory mucosa.

    PubMed

    Fulgione, Domenico; Trapanese, Martina; Buglione, Maria; Rippa, Daniela; Polese, Gianluca; Maresca, Viviana; Maselli, Valeria

    2017-08-01

    Animals recognize their surrounding environments through the sense of smell by detecting thousands of chemical odorants. Wild boars (Sus scrofa) completely depend on their ability to recognize chemical odorants: to detect food, during scavenging and searching partners, during breeding periods and to avoid potential predators. Wild piglets must be prepared for the chemical universe that they will enter after birth, and they show intense neuronal activity in the olfactory mucosa. With this in mind, we investigated the morpho-functional embryonic development of the olfactory mucosa in the wild boar (in five stages before birth). Using mRNA expression analysis of olfactory marker protein and neuropeptide Y, involved in the function of olfactory sensory neurons, we show early activation of the appropriate genes in the wild boar. We hypothesize olfactory pre-birth development in wild boar is highly adaptive. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. Cortico-subcortical metabolic correlates of olfactory processing in healthy resting subjects

    PubMed Central

    Alessandrini, Marco; Micarelli, Alessandro; Chiaravalloti, Agostino; Candidi, Matteo; Bruno, Ernesto; Di Pietro, Barbara; Schillaci, Orazio; Pagani, Marco

    2014-01-01

    A wide network of interconnected areas was previously found in neuroimaging studies involving normal as well as pathological subjects; however literature seems to suffer from a lack of investigation in glucose metabolism behaviour under olfactory condition. Thus, the present work describe for the first time a pure olfactory related brain response of metabolism by using 18F-fluorodeoxyglucose-Positron Emission Tomography/Computer Tomography in eleven resting subjects undergoing a neutral and a pure olfactory condition. By contrasting these experimental phases, it was possible to depict a re-organization pattern of default mode network structures in a relatively ecological environment. Moreover, by correlating such pattern with a battery of validated olfactory and neuropsychological tests, our work allowed in showing peculiar correlation data that could cluster the subjects sample in a certain range of normality. We believe the present study could integrate the current knowledge in olfactory research and could be a start-up for future contributions. PMID:24888510

  6. Multiorganismal insects: diversity and function of resident microorganisms.

    PubMed

    Douglas, Angela E

    2015-01-07

    All insects are colonized by microorganisms on the insect exoskeleton, in the gut and hemocoel, and within insect cells. The insect microbiota is generally different from microorganisms in the external environment, including ingested food. Specifically, certain microbial taxa are favored by the conditions and resources in the insect habitat, by their tolerance of insect immunity, and by specific mechanisms for their transmission. The resident microorganisms can promote insect fitness by contributing to nutrition, especially by providing essential amino acids, B vitamins, and, for fungal partners, sterols. Some microorganisms protect their insect hosts against pathogens, parasitoids, and other parasites by synthesizing specific toxins or modifying the insect immune system. Priorities for future research include elucidation of microbial contributions to detoxification, especially of plant allelochemicals in phytophagous insects, and resistance to pathogens; as well as their role in among-insect communication; and the potential value of manipulation of the microbiota to control insect pests.

  7. Multiorganismal Insects: Diversity and Function of Resident Microorganisms

    PubMed Central

    Douglas, Angela E.

    2015-01-01

    All insects are colonized by microorganisms on the insect exoskeleton, in the gut and hemocoel, and within insect cells. The insect microbiota is generally different from microorganisms in the external environment, including ingested food. Specifically, certain microbial taxa are favored by the conditions and resources in the insect habitat, by their tolerance of insect immunity, and by specific mechanisms for their transmission. The resident microorganisms can promote insect fitness by contributing to nutrition, especially by providing essential amino acids, B vitamins, and, for fungal partners, sterols. Some microorganisms protect their insect hosts against pathogens, parasitoids, and other parasites by synthesizing specific toxins or modifying the insect immune system. Priorities for future research include elucidation of microbial contributions to detoxification, especially of plant allelochemicals in phytophagous insects, and resistance to pathogens; as well as their role in among-insect communication; and the potential value of manipulation of the microbiota to control insect pests. PMID:25341109

  8. Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size

    PubMed Central

    Morrison, Filomene G.; Dias, Brian G.; Ressler, Kerry J.

    2015-01-01

    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. PMID:26420875

  9. Insects as a Nitrogen Source for Plants.

    PubMed

    Behie, Scott W; Bidochka, Michael J

    2013-07-31

    Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively) are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF) provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates.

  10. Insects as a Nitrogen Source for Plants

    PubMed Central

    Behie, Scott W.; Bidochka, Michael J.

    2013-01-01

    Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively) are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF) provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates. PMID:26462427

  11. [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.

  12. Insects: A nutritional alternative

    NASA Technical Reports Server (NTRS)

    Dufour, P. A.

    1981-01-01

    Insects are considered as potential food sources in space. Types of insects consumed are discussed. Hazards of insect ingestion are considered. Insect reproduction, requirements, and raw materials conversion are discussed. Nutrition properties and composition of insects are considered. Preparation of insects as human food is discussed.

  13. Behavioral and Neurophysiological Study of Olfactory Perception and Learning in Honeybees

    PubMed Central

    Sandoz, Jean Christophe

    2011-01-01

    The honeybee Apis mellifera has been a central insect model in the study of olfactory perception and learning for more than a century, starting with pioneer work by Karl von Frisch. Research on olfaction in honeybees has greatly benefited from the advent of a range of behavioral and neurophysiological paradigms in the Lab. Here I review major findings about how the honeybee brain detects, processes, and learns odors, based on behavioral, neuroanatomical, and neurophysiological approaches. I first address the behavioral study of olfactory learning, from experiments on free-flying workers visiting artificial flowers to laboratory-based conditioning protocols on restrained individuals. I explain how the study of olfactory learning has allowed understanding the discrimination and generalization ability of the honeybee olfactory system, its capacity to grant special properties to olfactory mixtures as well as to retain individual component information. Next, based on the impressive amount of anatomical and immunochemical studies of the bee brain, I detail our knowledge of olfactory pathways. I then show how functional recordings of odor-evoked activity in the brain allow following the transformation of the olfactory message from the periphery until higher-order central structures. Data from extra- and intracellular electrophysiological approaches as well as from the most recent optical imaging developments are described. Lastly, I discuss results addressing how odor representation changes as a result of experience. This impressive ensemble of behavioral, neuroanatomical, and neurophysiological data available in the bee make it an attractive model for future research aiming to understand olfactory perception and learning in an integrative fashion. PMID:22163215

  14. Behavioral and neurophysiological study of olfactory perception and learning in honeybees.

    PubMed

    Sandoz, Jean Christophe

    2011-01-01

    The honeybee Apis mellifera has been a central insect model in the study of olfactory perception and learning for more than a century, starting with pioneer work by Karl von Frisch. Research on olfaction in honeybees has greatly benefited from the advent of a range of behavioral and neurophysiological paradigms in the Lab. Here I review major findings about how the honeybee brain detects, processes, and learns odors, based on behavioral, neuroanatomical, and neurophysiological approaches. I first address the behavioral study of olfactory learning, from experiments on free-flying workers visiting artificial flowers to laboratory-based conditioning protocols on restrained individuals. I explain how the study of olfactory learning has allowed understanding the discrimination and generalization ability of the honeybee olfactory system, its capacity to grant special properties to olfactory mixtures as well as to retain individual component information. Next, based on the impressive amount of anatomical and immunochemical studies of the bee brain, I detail our knowledge of olfactory pathways. I then show how functional recordings of odor-evoked activity in the brain allow following the transformation of the olfactory message from the periphery until higher-order central structures. Data from extra- and intracellular electrophysiological approaches as well as from the most recent optical imaging developments are described. Lastly, I discuss results addressing how odor representation changes as a result of experience. This impressive ensemble of behavioral, neuroanatomical, and neurophysiological data available in the bee make it an attractive model for future research aiming to understand olfactory perception and learning in an integrative fashion.

  15. Evidence for partial overlap of male olfactory cues in lampreys

    USGS Publications Warehouse

    Buchinger, Tyler J.; Li, Ke; Huertas, Mar; Baker, Cindy F.; Jia, Liang; Hayes, Michael C.; Li, Weiming; Johnson, Nicholas S.

    2016-01-01

    Animals rely on a mosaic of complex information to find and evaluate mates. Pheromones, often comprised of multiple components, are considered to be particularly important for species-recognition in many species. While the evolution of species-specific pheromone blends is well-described in many insects, very few vertebrate pheromones have been studied in a macro-evolutionary context. Here, we report a phylogenetic comparison of multi-component male odours that guide reproduction in lampreys. Chemical profiling of sexually mature males from eleven species of lamprey, representing six of ten genera and two of three families, indicated the chemical profiles of sexually mature male odours are partially shared among species. Behavioural assays conducted with four species sympatric in the Laurentian Great Lakes indicated asymmetric female responses to heterospecific odours, where Petromyzon marinus were attracted to male odour collected from all species tested but other species generally preferred only the odour of conspecifics. Electro-olfactogram recordings from P. marinusindicated that although P. marinus exhibited behavioural responses to odours from males of all species, at least some of the compounds that elicited olfactory responses were different in conspecific male odours compared to heterospecific male odours. We conclude that some of the compounds released by sexually mature males are shared among species and elicit olfactory and behavioural responses in P. marinus, and suggest that our results provide evidence for partial overlap of male olfactory cues among lampreys. Further characterization of the chemical identities of odour components is needed to confirm shared pheromones among species.

  16. Olfactory modulation by dopamine in the context of aversive learning

    PubMed Central

    Riffell, Jeffrey A.; Martin, Joshua P.; Gage, Stephanie L.; Nighorn, Alan J.

    2012-01-01

    The need to detect and process sensory cues varies in different behavioral contexts. Plasticity in sensory coding can be achieved by the context-specific release of neuromodulators in restricted brain areas. The context of aversion triggers the release of dopamine in the insect brain, yet the effects of dopamine on sensory coding are unknown. In this study, we characterize the morphology of dopaminergic neurons that innervate each of the antennal lobes (ALs; the first synaptic neuropils of the olfactory system) of the moth Manduca sexta and demonstrate with electrophysiology that dopamine enhances odor-evoked responses of the majority of AL neurons while reducing the responses of a small minority. Because dopamine release in higher brain areas mediates aversive learning we developed a naturalistic, ecologically inspired aversive learning paradigm in which an innately appetitive host plant floral odor is paired with a mimic of the aversive nectar of herbivorized host plants. This pairing resulted in a decrease in feeding behavior that was blocked when dopamine receptor antagonists were injected directly into the ALs. These results suggest that a transient dopaminergic enhancement of sensory output from the AL contributes to the formation of aversive memories. We propose a model of olfactory modulation in which specific contexts trigger the release of different neuromodulators in the AL to increase olfactory output to downstream areas of processing. PMID:22552185

  17. Insect evolution.

    PubMed

    Engel, Michael S

    2015-10-05

    It goes without saying that insects epitomize diversity, and with over a million documented species they stand out as one of the most remarkable lineages in the 3.5-billion-year history of life on earth (Figure 1). This reality is passé to even the layperson and is taken for granted in the same way none of us think much of our breathing as we go about our day, and yet insects are just as vital to our existence. Insects are simultaneously familiar and foreign to us, and while a small fraction are beloved or reviled, most are simply ignored. These inexorable evolutionary overachievers outnumber us all, their segmented body plan is remarkably labile, they combine a capacity for high rates of speciation with low levels of natural extinction, and their history of successes eclipses those of the more familiar ages of dinosaurs and mammals alike. It is their evolution - persisting over vast expanses of geological time and inextricably implicated in the diversification of other lineages - that stands as one of the most expansive subjects in biology.

  18. Olfactory receptor cells on the cockroach antennae: responses to the direction and rate of change in food odour concentration.

    PubMed

    Hinterwirth, Armin; Zeiner, Reinhard; Tichy, Harald

    2004-06-01

    In insects, information about food odour is encoded by olfactory receptor cells with characteristic response spectra, located in several types of cuticular sensilla. Within short, hair-like sensilla on the cockroach's antenna, antagonistic pairs of olfactory receptor cells shape information inflow to the CNS by providing excitatory responses for both increases and decreases in food odour concentration. The segregation of food odour information into parallel ON and OFF responses suggests that temporal concentration changes become enhanced in the sensory output. When food odour concentration changes slowly and continuously up and down with smooth transition from one direction to another, the ON and OFF olfactory cells not only signal a succession of odour concentrations but also the rate with which odour concentration happens to be changing. Access to the values of such cues is of great use to an insect orientating to an odour source. With them they may extract concentration gradients from odour plumes.

  19. Paraneoplastic syndromes in olfactory neuroblastoma

    PubMed Central

    Gabrych, Anna; Czapiewski, Piotr; Sworczak, Krzysztof

    2015-01-01

    Olfactory neuroblastoma (ONB) is a rare malignant neoplasm of sinonasal tract, derived from olfactory epithelium. Unilateral nasal obstruction, epistaxis, sinusitis, and headaches are common symptoms. Olfactory neuroblastoma shows neuroendocrine differentiation and similarly to other neuroendocrine tumors can produce several types of peptic substances and hormones. Excess production of these substances can be responsible for different types of endocrinological paraneoplastic syndromes (PNS). Moreover, besides endocrinological, in ONB may also occur neurological PNS, caused by immune cross-reactivity between tumor and normal host tissues in the nervous system. Paraneoplastic syndromes in ONB include: syndrome of inappropriate ADH secretion (SIADH), ectopic ACTH syndrome (EAS), humoral hypercalcemia of malignancy (HHM), hypertension due to catecholamine secretion by tumor, opsoclonus-myoclonus-ataxia (OMA) and paraneoplastic cerebellar degeneration. Paraneoplastic syndromes in ONB tend to have atypical features, therefore diagnosis may be difficult. In this review, we described initial symptoms, patterns of presentation, treatment and outcome of paraneoplastic syndromes in ONB, reported in the literature. PMID:26199564

  20. Cadmium-induced olfactory dysfunction in rainbow trout: Effects of binary and quaternary metal mixtures.

    PubMed

    Dew, William A; Veldhoen, Nik; Carew, Amanda C; Helbing, Caren C; Pyle, Greg G

    2016-03-01

    A functioning olfactory response is essential for fish to be able to undertake essential behaviors. The majority of work investigating the effects of metals on the olfactory response of fish has focused on single-metal exposures. In this study we exposed rainbow trout to cadmium, copper, nickel, zinc, or a mixture of these four metals at or below the current Canadian Council of Ministers of the Environment guidelines for the protection of aquatic life. Measurement of olfactory acuity using an electro-olfactogram demonstrated that cadmium causes significant impairment of the entire olfactory system, while the other three metals or the mixture of all four metals did not. Binary mixtures with cadmium and each of the other metals demonstrated that nickel and zinc, but not copper, protect against cadmium-induced olfactory dysfunction. Testing was done to determine if the protection from cadmium-induced olfactory dysfunction could be explained by binding competition between cadmium and the other metals at the cell surface, or if the protection could be explained by an up-regulation of an intracellular detoxification pathway, namely metallothionein. This study is the first to measure the effects of binary and quaternary metal mixtures on the olfactory response of fish, something that will aid in future assessments of the effects of metals on the environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Edible Insects in China: Utilization and Prospects.

    PubMed

    Feng, Ying; Chen, Xiao-Ming; Zhao, Min; He, Zhao; Sun, Long; Wang, Cheng-Ye; Ding, Wei-Feng

    2017-02-22

    reared completely in captivity or are partially raised in captivity, and the insect habitat is manipulated to increase production. Depending on the type of relationship the insect has with humans, plants, and the environment, different farming strategies are used. The social and scientific communities must work together to promote the use of insects as food and feed. This article is protected by copyright. All rights reserved.

  2. Olfactory epithelium in the olfactory recess: a case study in new world leaf-nosed bats.

    PubMed

    Eiting, Thomas P; Smith, Timothy D; Dumont, Elizabeth R

    2014-11-01

    The olfactory recess (OR) is a restricted space at the back of the nasal fossa in many mammals that is thought to improve olfactory function. Mammals that have an olfactory recess are usually described as keen-scented, while those that do not are typically thought of as less reliant on olfaction. However, the presence of an olfactory recess is not a binary trait. Many mammal families have members that vary substantially in the size and complexity of the olfactory recess. There is also variation in the amount of olfactory epithelium (OE) that is housed in the olfactory recess. Among New World leaf-nosed bats (family Phyllostomidae), species vary by over an order of magnitude in how much of their total OE lies within the OR. Does this variation relate to previously documented neuroanatomical proxies for olfactory reliance? Using data from 12 species of phyllostomid bats, we addressed the hypothesis that the amount of OE within the OR relates to a species' dependence on olfaction, as measured by two commonly used neuroanatomical metrics, the size of the olfactory bulb, and the number of glomeruli in the olfactory bulb, which are the first processing units within the olfactory signal cascade. We found that the percentage of OE within the OR does not relate to either measure of olfactory "ability." This suggests that olfactory reliance is not reflected in the size of the olfactory recess. We explore other roles that the olfactory recess may play. © 2014 Wiley Periodicals, Inc.

  3. Olfactory experience modifies semiochemical responses in a bark beetle predator.

    PubMed

    Costa, Arnaud; Reeve, John D

    2011-11-01

    A typical feature of forest insect pests is their tendency to undergo large fluctuations in abundance, which can jeopardize the persistence of their predaceous natural enemies. One strategy that these predators may adopt to cope with these fluctuations would be to respond to sensory cues for multiple prey species. Another possible adaptation to temporal variation in the prey community could involve the learning of prey cues and switching behavior. We conducted three experiments to investigate the ability of the generalist bark beetle predator Thanasimus dubius (F.) (Coleoptera: Cleridae) to respond to different prey signals and to investigate the effect of olfactory experience. We first conducted a field choice test and a wind tunnel experiment to examine the kairomonal response of individual predators toward prey pheromone components (frontalin, ipsenol, ipsdienol, sulcatol) along with the pine monoterpene α-pinene, which is a volatile compound from the host of the prey. We also presented semiochemically naive predators with two prey pheromone components, frontalin and ipsenol, alone or associated with a reward. Our results showed that T. dubius populations are composed of generalists that can respond to a broad range of kairomonal signals. Naive T. dubius also were more attracted to ipsenol following its association with a reward. This work constitutes the first evidence that the behavior of a predatory insect involved in bark beetle population dynamics is influenced by previous olfactory experience, and provides a potential explanation for the pattern of prey switching observed in field studies.

  4. The sox gene Dichaete is expressed in local interneurons and functions in development of the Drosophila adult olfactory circuit.

    PubMed

    Melnattur, Krishna V; Berdnik, Daniela; Rusan, Zeid; Ferreira, Christopher J; Nambu, John R

    2013-02-01

    In insects, the primary sites of integration for olfactory sensory input are the glomeruli in the antennal lobes. Here, axons of olfactory receptor neurons synapse with dendrites of the projection neurons that relay olfactory input to higher brain centers, such as the mushroom bodies and lateral horn. Interactions between olfactory receptor neurons and projection neurons are modulated by excitatory and inhibitory input from a group of local interneurons. While significant insight has been gleaned into the differentiation of olfactory receptor and projection neurons, much less is known about the development and function of the local interneurons. We have found that Dichaete, a conserved Sox HMG box gene, is strongly expressed in a cluster of LAAL cells located adjacent to each antennal lobe in the adult brain. Within these clusters, Dichaete protein expression is detected in both cholinergic and GABAergic local interneurons. In contrast, Dichaete expression is not detected in mature or developing projection neurons, or developing olfactory receptor neurons. Analysis of novel viable Dichaete mutant alleles revealed misrouting of specific projection neuron dendrites and axons, and alterations in glomeruli organization. These results suggest noncell autonomous functions of Dichaete in projection neuron differentiation as well as a potential role for Dichaete-expressing local interneurons in development of the adult olfactory circuitry.

  5. Topological and Functional Characterization of an Insect Gustatory Receptor

    PubMed Central

    Zhang, Hui-Jie; Anderson, Alisha R.; Trowell, Stephen C.; Luo, A-Rong; Xiang, Zhong-Huai; Xia, Qing-You

    2011-01-01

    Insect gustatory receptors are predicted to have a seven-transmembrane structure and are distantly related to insect olfactory receptors, which have an inverted topology compared with G-protein coupled receptors, including mammalian olfactory receptors. In contrast, the topology of insect gustatory receptors remains unknown. Except for a few examples from Drosophila, the specificity of individual insect gustatory receptors is also unknown. In this study, the total number of identified gustatory receptors in Bombyx mori was expanded from 65 to 69. BmGr8, a silkmoth gustatory receptor from the sugar receptor subfamily, was expressed in insect cells. Membrane topology studies on BmGr8 indicate that, like insect olfactory receptors, it has an inverted topology relative to G protein-coupled receptors. An orphan GR from the bitter receptor family, BmGr53, yielded similar results. We infer, from the finding that two distantly related BmGrs have an intracellular N-terminus and an odd number of transmembrane spans, that this is likely to be a general topology for all insect gustatory receptors. We also show that BmGr8 functions independently in Sf9 cells and responds in a concentration-dependent manner to the polyalcohols myo-inositol and epi-inositol but not to a range of mono- and di-saccharides. BmGr8 is the first chemoreceptor shown to respond specifically to inositol, an important or essential nutrient for some Lepidoptera. The selectivity of BmGr8 responses is consistent with the known responses of one of the gustatory receptor neurons in the lateral styloconic sensilla of B. mori, which responds to myo-inositol and epi-inositol but not to allo-inositol. PMID:21912618

  6. Topological and functional characterization of an insect gustatory receptor.

    PubMed

    Zhang, Hui-Jie; Anderson, Alisha R; Trowell, Stephen C; Luo, A-Rong; Xiang, Zhong-Huai; Xia, Qing-You

    2011-01-01

    Insect gustatory receptors are predicted to have a seven-transmembrane structure and are distantly related to insect olfactory receptors, which have an inverted topology compared with G-protein coupled receptors, including mammalian olfactory receptors. In contrast, the topology of insect gustatory receptors remains unknown. Except for a few examples from Drosophila, the specificity of individual insect gustatory receptors is also unknown. In this study, the total number of identified gustatory receptors in Bombyx mori was expanded from 65 to 69. BmGr8, a silkmoth gustatory receptor from the sugar receptor subfamily, was expressed in insect cells. Membrane topology studies on BmGr8 indicate that, like insect olfactory receptors, it has an inverted topology relative to G protein-coupled receptors. An orphan GR from the bitter receptor family, BmGr53, yielded similar results. We infer, from the finding that two distantly related BmGrs have an intracellular N-terminus and an odd number of transmembrane spans, that this is likely to be a general topology for all insect gustatory receptors. We also show that BmGr8 functions independently in Sf9 cells and responds in a concentration-dependent manner to the polyalcohols myo-inositol and epi-inositol but not to a range of mono- and di-saccharides. BmGr8 is the first chemoreceptor shown to respond specifically to inositol, an important or essential nutrient for some Lepidoptera. The selectivity of BmGr8 responses is consistent with the known responses of one of the gustatory receptor neurons in the lateral styloconic sensilla of B. mori, which responds to myo-inositol and epi-inositol but not to allo-inositol.

  7. Insect abatement system

    NASA Technical Reports Server (NTRS)

    Spiro, Clifford Lawrence (Inventor); Burnell, Timothy Brydon (Inventor); Wengrovius, Jeffrey Hayward (Inventor)

    1997-01-01

    An insect abatement system prevents adhesion of insect debris to surfaces which must be kept substantially free of insect debris. An article is coated with an insect abatement coating comprising polyorganosiloxane with a Shore A hardness of less than 50 and a tensile strength of less than 4 MPa. A method for preventing the adhesion of insect debris to surfaces includes the step of applying an insect abatement coating to a surface which must be kept substantially free of insect debris.

  8. Insect inspiration

    NASA Astrophysics Data System (ADS)

    McIntosh, Andy; Beheshti, Novid

    2008-04-01

    The innocuous looking bombardier beetle is one of the most remarkable creatures around. This tiny insect is endowed with a defence mechanism that would be the envy of any comic-strip superhero - it can fight off any spider, frog, ant or bird that comes too close by blasting the attacker with a powerful jet of hot, toxic fluid. Furthermore, the beetle can aim its weapon in any direction (even over its head) with pinpoint accuracy, and can reach distances of up to 20 cm with its spray.

  9. Physiological and morphological characterization of honeybee olfactory neurons combining electrophysiology, calcium imaging and confocal microscopy.

    PubMed

    Galizia, C G; Kimmerle, B

    2004-01-01

    The insect antennal lobe is the first brain structure to process olfactory information. Like the vertebrate olfactory bulb the antennal lobe is substructured in olfactory glomeruli. In insects, glomeruli can be morphologically identified, and have characteristic olfactory response profiles. Local neurons interconnect glomeruli, and output (projection) neurons project to higher-order brain centres. The relationship between their elaborate morphology and their physiology is not understood. We recorded electrophysiologically from antennal lobe neurons, and iontophoretically injected a calcium-sensitive dye. We then measured their spatio-temporal calcium responses to a variety of odours. Finally, we confocally reconstructed the neurons, and identified the innervated glomeruli. An increase or decrease in spiking frequency corresponded to an intracellular calcium increase or decrease in the cell. While intracellular recordings generally lasted between 10 and 30 min, calcium imaging was stable for up to 2 h, allowing a more detailed physiological analysis. The responses indicate that heterogeneous local neurons get input in the glomerulus in which they branch most strongly. In many cases, the physiological response properties of the cells corresponded to the known response profile of the innervated glomerulus. In other words, the large variety of response profiles generally found when comparing antennal lobe neurons is reduced to a more predictable response profile when the innervated glomerulus is known.

  10. Identification and expression pattern of candidate olfactory genes in Chrysoperla sinica by antennal transcriptome analysis.

    PubMed

    Li, Zhao-Qun; Zhang, Shuai; Luo, Jun-Yu; Wang, Si-Bao; Wang, Chun-Yi; Lv, Li-Min; Dong, Shuang-Lin; Cui, Jin-Jie

    2015-09-01

    Chrysoperla sinica is one of the most prominent natural enemies of many agricultural pests. Host seeking in insects is strongly mediated by olfaction. Understanding the sophisticated olfactory system of insect antennae is crucial for studying the physiological bases of olfaction and could also help enhance the effectiveness of C. sinica in biological control. Obtaining olfactory genes is a research priority for investigating the olfactory system in this species. However, no olfaction sequence information is available for C. sinica. Consequently, we sequenced female- and male-antennae transcriptome of C. sinica. Many candidate chemosensory genes were identified, including 12 odorant-binding proteins (OBPs), 19 chemosensory proteins (CSPs), 37 odorant receptors (ORs), and 64 ionotropic receptors from C. sinica. The expression patterns of 12 OBPs, 19 CSPs and 37 ORs were determined by RT-PCR, and demonstrated antennae-dominantly expression of most OBP and OR genes. Our finding provided large scale genes for further investigation on the olfactory system of C. sinica at the molecular level.

  11. 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

  12. Hypothyroidism Affects Olfactory Evoked Potentials.

    PubMed

    Świdziński, Teodor; Linkowska-Świdzińska, Kamila; Czerniejewska-Wolska, Hanna; Wiskirska-Woźnica, Bożena; Owecki, Maciej; Głowacka, Maria Danuta; Frankowska, Anna; Łącka, Katarzyna; Glapiński, Mariusz; Maciejewska-Szaniec, Zofia; Świdziński, Piotr

    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.

  13. Strong single-fiber sensory inputs to olfactory cortex: implications for olfactory coding.

    PubMed

    Franks, Kevin M; Isaacson, Jeffry S

    2006-02-02

    Olfactory information is first encoded in a combinatorial fashion by olfactory bulb glomeruli, which individually represent distinct chemical features of odors. This information is then transmitted to piriform (olfactory) cortex, via axons of olfactory bulb mitral and tufted (M/T) cells, where it is presumed to form the odor percept. However, mechanisms governing the integration of sensory information in mammalian olfactory cortex are unclear. Here we show that single M/T cells can make powerful connections with cortical pyramidal cells, and coincident input from few M/T cells is sufficient to elicit spike output. These findings suggest that odor coding is broad and distributed in olfactory cortex.

  14. 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

  15. Antennal uridine diphosphate (UDP)-glycosyltransferases in a pest insect: diversity and putative function in odorant and xenobiotics clearance.

    PubMed

    Bozzolan, F; Siaussat, D; Maria, A; Durand, N; Pottier, M-A; Chertemps, T; Maïbèche-Coisne, M

    2014-10-01

    Uridine diphosphate UDP-glycosyltransferases (UGTs) are detoxification enzymes widely distributed within living organisms. They are involved in the biotransformation of various lipophilic endogenous compounds and xenobiotics, including odorants. Several UGTs have been reported in the olfactory organs of mammals and involved in olfactory processing and detoxification within the olfactory mucosa but, in insects, this enzyme family is still poorly studied. Despite recent transcriptomic analyses, the diversity of antennal UGTs in insects has not been investigated. To date, only three UGT cDNAs have been shown to be expressed in insect olfactory organs. In the present study, we report the identification of eleven putative UGTs expressed in the antennae of the model pest insect Spodoptera littoralis. Phylogenetic analysis revealed that these UGTs belong to five different families, highlighting their structural diversity. In addition, two genes, UGT40R3 and UGT46A6, were either specifically expressed or overexpressed in the antennae, suggesting specific roles in this sensory organ. Exposure of male moths to the sex pheromone and to a plant odorant differentially downregulated the transcription levels of these two genes, revealing for the first time the regulation of insect UGTs by odorant exposure. Moreover, the specific antennal gene UGT46A6 was upregulated by insecticide topical application on antennae, suggesting its role in the protection of the olfactory organ towards xenobiotics. This work highlights the structural and functional diversity of UGTs within this highly specialized tissue. © 2014 The Royal Entomological Society.

  16. Simple and Computer-assisted Olfactory Testing for Mice.

    PubMed

    Brai, Emanuele; Alberi, Lavinia

    2015-06-15

    Olfaction is highly conserved among species and is required for reproduction and survival. In humans, olfaction is also one of the senses that is affected with aging and is a strong predictor of neurodegenerative diseases. Thus, olfaction testing is used as a non-invasive diagnostic method to detect neurological deficits early on. In order to understand the mechanisms underlying olfactory network susceptibility, olfactory research in rodents has gained momentum in the past decade. Here, we present a very simple, time efficient and reproducible olfactory testing method of innate odor perception and sensitivity in mice without the need of any prior food or water restriction. The tests are performed in a familiar environment to the mice, require only the scents and a 2 min session of odorant exposure. The analysis is performed, post-hoc, using computer-assisted commands on ImageJ and can be, therefore, carried out from start to end by one researcher. This protocol does not require any special hardware or setup and is indicated for any laboratory interested in testing olfactory perception and sensitivity.

  17. Simple and Computer-assisted Olfactory Testing for Mice

    PubMed Central

    Brai, Emanuele; Alberi, Lavinia

    2015-01-01

    Olfaction is highly conserved among species and is required for reproduction and survival. In humans, olfaction is also one of the senses that is affected with aging and is a strong predictor of neurodegenerative diseases. Thus, olfaction testing is used as a non-invasive diagnostic method to detect neurological deficits early on. In order to understand the mechanisms underlying olfactory network susceptibility, olfactory research in rodents has gained momentum in the past decade. Here, we present a very simple, time efficient and reproducible olfactory testing method of innate odor perception and sensitivity in mice without the need of any prior food or water restriction. The tests are performed in a familiar environment to the mice, require only the scents and a 2 min session of odorant exposure. The analysis is performed, post-hoc, using computer-assisted commands on ImageJ and can be, therefore, carried out from start to end by one researcher. This protocol does not require any special hardware or setup and is indicated for any laboratory interested in testing olfactory perception and sensitivity. PMID:26131595

  18. Partial unilateral lesions of the mushroom bodies affect olfactory learning in honeybees Apis mellifera L.

    PubMed

    Komischke, Bernhard; Sandoz, Jean-Christophe; Malun, Dagmar; Giurfa, Martin

    2005-01-01

    The mushroom bodies (MBs) are central structures in the insect brain that have been associated with olfactory learning and memory. Here we used hydroxyurea (HU) to treat honeybee larvae and induce partial MB ablations at the adult stage. We studied olfactory learning in honeybees with unilateral loss of the median calyces of their MBs and compared their ability to solve different forms of olfactory discrimination. When odorants were delivered in a side-specific manner, ablated bees could not solve either discrimination of the unambiguous problem (Paradigm 1: A+, B- on one antenna, C+, D- on the other; A+B-/C+D-) whereas they could solve at least one of both discriminations of the ambiguous problem (Paradigm 2: A+B-/A-B+), namely that proposed to their intact brain side. Non-ablated bees could learn side-specific discriminations on both brain sides. When odorants were delivered simultaneously to both antennae (Paradigm 3: A+B-C+D-), HU-ablated bees learned slower than HU-normal bees. Thus, in all three paradigms, the unilateral loss of a median calyx affected olfactory learning. We propose that the MBs are required for solving elemental olfactory tasks whose complexity is increased by the number of stimuli involved and that MB ablations could have an effect on the inhibition of information exchange between brain hemispheres.

  19. Geographical matching of volatile signals and pollinator olfactory responses in a cycad brood-site mutualism

    PubMed Central

    Suinyuy, Terence N.; Donaldson, John S.; Johnson, Steven D.

    2015-01-01

    Brood-site mutualisms represent extreme levels of reciprocal specialization between plants and insect pollinators, raising questions about whether these mutualisms are mediated by volatile signals and whether these signals and insect responses to them covary geographically in a manner expected from coevolution. Cycads are an ancient plant lineage in which almost all extant species are pollinated through brood-site mutualisms with insects. We investigated whether volatile emissions and insect olfactory responses are matched across the distribution range of the African cycad Encephalartos villosus. This cycad species is pollinated by the same beetle species across its distribution, but cone volatile emissions are dominated by alkenes in northern populations, and by monoterpenes and a pyrazine compound in southern populations. In reciprocal choice experiments, insects chose the scent of cones from the local region over that of cones from the other region. Antennae of beetles from northern populations responded mainly to alkenes, while those of beetles from southern populations responded mainly to pyrazine. In bioassay experiments, beetles were most strongly attracted to alkenes in northern populations and to the pyrazine compound in southern populations. Geographical matching of cone volatiles and pollinator olfactory preference is consistent with coevolution in this specialized mutualism. PMID:26446814

  20. Geographical matching of volatile signals and pollinator olfactory responses in a cycad brood-site mutualism.

    PubMed

    Suinyuy, Terence N; Donaldson, John S; Johnson, Steven D

    2015-10-07

    Brood-site mutualisms represent extreme levels of reciprocal specialization between plants and insect pollinators, raising questions about whether these mutualisms are mediated by volatile signals and whether these signals and insect responses to them covary geographically in a manner expected from coevolution. Cycads are an ancient plant lineage in which almost all extant species are pollinated through brood-site mutualisms with insects. We investigated whether volatile emissions and insect olfactory responses are matched across the distribution range of the African cycad Encephalartos villosus. This cycad species is pollinated by the same beetle species across its distribution, but cone volatile emissions are dominated by alkenes in northern populations, and by monoterpenes and a pyrazine compound in southern populations. In reciprocal choice experiments, insects chose the scent of cones from the local region over that of cones from the other region. Antennae of beetles from northern populations responded mainly to alkenes, while those of beetles from southern populations responded mainly to pyrazine. In bioassay experiments, beetles were most strongly attracted to alkenes in northern populations and to the pyrazine compound in southern populations. Geographical matching of cone volatiles and pollinator olfactory preference is consistent with coevolution in this specialized mutualism.

  1. Integration of Visual and Olfactory Cues in Host Plant Identification by the Asian Longhorned Beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae)

    PubMed Central

    L.Yv, Fei; Hai, Xiaoxia; Wang, Zhigang; Yan, Aihua; Liu, Bingxiang; Bi, Yongguo

    2015-01-01

    Some insects use host and mate cues, including odor, color, and shape, to locate and recognize their preferred hosts and mates. Previous research has shown that the Asian longicorn beetle, Anoplophora glabripennis (Motschulsky), uses olfactory cues to locate host plants and differentiate them from non-host plants. However, whether A. glabripennis adults use visual cues or a combination of visual and olfactory cues remains unclear. In this study, we tested the host location and recognition behavior in A. glabripennis, which infests a number of hardwood species and causes considerable economic losses in North America, Europe and Asia. We determined the relative importance of visual and olfactory cues from Acer negundo in host plant location and recognition, as well as in the discrimination of non-host plants (Sabina chinensis and Pinus bungeana), by female and male A. glabripennis. Visual and olfactory cues from the host plants (A. negundo), alone and combined, attracted significantly more females and males than equivalent cues from non-host plants (S. chinensis and P. bungeana). Furthermore, the combination of visual and olfactory cues of host plants attracted more adults than either cue alone, and visual cues alone attracted significantly more adults than olfactory cues alone. This finding suggests that adult A. glabripennis has an innate preference for the visual and/or olfactory cues of its host plants (A. negundo) over those of the non-host plant and visual cues are initially more important than olfactory cues for orientation; furthermore, this finding also suggests that adults integrate visual and olfactory cues to find their host plants. Our results indicate that different modalities of host plant cues should be considered together to understand fully the communication between host plants and Asian longhorned beetles. PMID:26556100

  2. Polyphenism in insects.

    PubMed

    Simpson, Stephen J; Sword, Gregory A; Lo, Nathan

    2011-09-27

    Polyphenism is the phenomenon where two or more distinct phenotypes are produced by the same genotype. Examples of polyphenism provide some of the most compelling systems for the study of epigenetics. Polyphenisms are a major reason for the success of the insects, allowing them to partition life history stages (with larvae dedicated to feeding and growth, and adults dedicated to reproduction and dispersal), to adopt different phenotypes that best suit predictable environmental changes (seasonal morphs), to cope with temporally heterogeneous environments (dispersal morphs), and to partition labour within social groups (the castes of eusocial insects). We survey the status of research on some of the best known examples of insect polyphenism, in each case considering the environmental cues that trigger shifts in phenotype, the neurochemical and hormonal pathways that mediate the transformation, the molecular genetic and epigenetic mechanisms involved in initiating and maintaining the polyphenism, and the adaptive and life-history significance of the phenomenon. We conclude by highlighting some of the common features of these examples and consider future avenues for research on polyphenism.

  3. Molecular determinants of odorant receptor function in insects.

    PubMed

    Ray, Anandasankar; van Naters, Wynand Goes; Carlson, John R

    2014-09-01

    The olfactory system of Drosophila melanogaster provides a powerful model to study molecular and cellular mechanisms underlying function of a sensory system. In the 1970s Siddiqi and colleagues pioneered the application of genetics to olfactory research and isolated several mutant Drosophila with odorant-specific defects in olfactory behaviour, suggesting that odorants are detected differentially by the olfactory system. Since then basic principles of olfactory system function and development have emerged using Drosophila as a model. Nearly four decades later we can add computational methods to further our understanding of how specific odorants are detected by receptors. Using a comparative approach we identify two categories of short amino acid sequence motifs: ones that are conserved family-wide predominantly in the C-terminal half of most receptors, and ones that are present in receptors that detect a specific odorant, 4-methylphenol, found predominantly in the N-terminal half. The odorant-specific sequence motifs are predictors of phenol detection in Anopheles gambiae and other insects, suggesting they are likely to participate in odorant binding. Conversely, the family-wide motifs are expected to participate in shared functions across all receptors and a mutation in the most conserved motif leads to a reduction in odor response. These findings lay a foundation for investigating functional domains within odorant receptors that can lead to a molecular understanding of odor detection.

  4. What Makes an Insect an Insect?

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides background information on characteristics common to all insects, activities, and student materials (ready-to-copy games, puzzles, coloring pages, worksheets, and/or mazes) which describe: how insects are classified; how they are different from other animals; and the main insect characteristics. Activities include recommended age levels,…

  5. Antennal transcriptome and differential expression of olfactory genes in the yellow peach moth, Conogethes punctiferalis (Lepidoptera: Crambidae)

    PubMed Central

    Jia, Xiao-Jian; Wang, Hai-Xiang; Yan, Zeng-Guang; Zhang, Min-Zhao; Wei, Chun-Hua; Qin, Xiao-Chun; Ji, Wei-Rong; Falabella, Patrizia; Du, Yan-Li

    2016-01-01

    The yellow peach moth (YPM), Conogethes punctiferalis (Guenée), is a multivoltine insect pest of crops and fruits. Antennal-expressed receptors are important for insects to detect olfactory cues for host finding, mate attraction and oviposition site selection. However, few olfactory related genes were reported in YPM until now. In the present study, we sequenced and characterized the antennal transcriptomes of male and female YPM. In total, 15 putative odorant binding proteins (OBPs), 46 putative odorant receptors (ORs) and 7 putative ionotropic receptors (IRs) were annotated and identified as olfactory-related genes of C. punctiferalis. Further analysis of RT-qPCR revealed that all these olfactory genes are primarily or uniquely expressed in male and female antennae. Among which, 3 OBPs (OBP4, OBP8 and PBP2) and 4 ORs (OR22, OR26, OR44 and OR46) were specially expressed in male antennae, whereas 4 ORs (OR5, OR16, OR25 and OR42) were primarily expressed in female antennae. The predicted protein sequences were compared with homologs in other lepidopteran species and model insects, which showed high sequence homologies between C. punctiferalis and O. furnacalis. Our work allows for further functional studies of pheromone and general odorant detection genes, which might be meaningful targets for pest management. PMID:27364081

  6. Human olfactory neurons respond to odor stimuli with an increase in cytoplasmic Ca2+.

    PubMed Central

    Restrepo, D; Okada, Y; Teeter, J H; Lowry, L D; Cowart, B; Brand, J G

    1993-01-01

    The sense of smell allows terrestrial animals to collect information about the chemical nature of their environment through the detection of airborne molecules. In humans smell is believed to play an important role in protecting the organism from environmental hazards such as fire, gas leaks and spoiled food, in determining the flavor of foods, and perhaps in infant-parent bonding. In addition, the study of human olfaction is relevant to a number of medical problems that result in olfactory dysfunction, which can affect nutritional state, and to the study of the etiology of neurodegenerative diseases which manifest themselves in the olfactory epithelium. Although much is known about behavioral aspects of human olfaction, little is understood about the underlying cellular mechanisms in humans. Here we report that viable human olfactory neurons (HON) can be isolated from olfactory tissue biopsies, and we find that HON respond to odorants with an increase in intracellular calcium concentration ([Cai]). Images FIGURE 2 PMID:8369416

  7. Field Survey Measures of Olfaction: The Olfactory Function Field Exam (OFFE)

    PubMed Central

    Kern, David W.; Wroblewski, Kristen E.; Schumm, L. Philip; Pinto, Jayant M.; McClintock, Martha K.

    2016-01-01

    Population-based field research on human olfaction has been limited by a lack of feasible assessment tools. Previous olfactory survey research has measured only odor identification, with no research being done on odor detection (i.e., a person's sensitivity to detect a particular odor). Laboratory studies suggest that deficits in both aspects of olfactory function may be related to physical health, mental health and cognition, social function, including overall quality of life, and even mortality. However, field studies are needed to validate and extend these findings in large representative samples. Here we describe the olfactory function field exam, an instrument that can be deployed in field environments by lay interviewers to evaluate both odor identification and odor detection rapidly, practically, and accurately. Use of this new survey tool in future field-based population health studies will elucidate the impact of olfactory function on a myriad of health and social conditions. PMID:27226782

  8. Temporal Processing in the Olfactory System: Can We See a Smell?

    PubMed Central

    Gire, David H.; Restrepo, Diego; Sejnowski, Terrence J.; Greer, Charles; De Carlos, Juan A.; Lopez-Mascaraque, Laura

    2013-01-01

    Sensory processing circuits in the visual and olfactory systems receive input from complex, rapidly changing environments. Although patterns of light and plumes of odor create different distributions of activity in the retina and olfactory bulb, both structures use what appears on the surface similar temporal coding strategies to convey information to higher areas in the brain. We compare temporal coding in the early stages of the olfactory and visual systems, highlighting recent progress in understanding the role of time in olfactory coding during active sensing by behaving animals. We also examine studies that address the divergent circuit mechanisms that generate temporal codes in the two systems, and find that they provide physiological information directly related to functional questions raised by neuroanatomical studies of Ramon y Cajal over a century ago. Consideration of differences in neural activity in sensory systems contributes to generating new approaches to understand signal processing. PMID:23664611

  9. The importance of the olfactory sense in the human behavior and evolution

    PubMed Central

    Mella, C; Georgescu, M; Perederco, C

    2009-01-01

    Not long ago it was believed that the human olfactory sense had a low importance, a vision which turned into the exploration of the environment. Recent studies have shown that, despite the weak representation of the olfactory receptor common in other species too, the cortical areas of integration of the olfactory sensations are very large and have important interconnections with memory, language, and neuro–vegetative areas. In humans, olfaction has a small contribution in identifying objects or other people, but plays an important social and emotional part. People learn to love or to hate certain foods or objects only by appreciating their odor and this proved to be a very important economic factor. The most significant role of olfactory signals in humans appears to be the modulation of their behavior and interpersonal relationships, of their affiliation to certain groups or social classes, having a major influence in their tastes and personality. PMID:20108540

  10. An olfactory cocktail party: figure-ground segregation of odorants in rodents.

    PubMed

    Rokni, Dan; Hemmelder, Vivian; Kapoor, Vikrant; Murthy, Venkatesh N

    2014-09-01

    In odorant-rich environments, animals must be able to detect specific odorants of interest against variable backgrounds. However, studies have found that both humans and rodents are poor at analyzing the components of odorant mixtures, suggesting that olfaction is a synthetic sense in which mixtures are perceived holistically. We found that mice could be easily trained to detect target odorants embedded in unpredictable and variable mixtures. To relate the behavioral performance to neural representation, we imaged the responses of olfactory bulb glomeruli to individual odors in mice expressing the Ca(2+) indicator GCaMP3 in olfactory receptor neurons. The difficulty of segregating the target from the background depended strongly on the extent of overlap between the glomerular responses to target and background odors. Our study indicates that the olfactory system has powerful analytic abilities that are constrained by the limits of combinatorial neural representation of odorants at the level of the olfactory receptors.

  11. Does iron deficiency anemia affect olfactory function?

    PubMed

    Dinc, Mehmet Emre; Dalgic, Abdullah; Ulusoy, Seckin; Dizdar, Denizhan; Develioglu, Omer; Topak, Murat

    2016-07-01

    Conclusion This study found a negative effect of IDA on olfactory function. IDA leads to a reduction in olfactory function, and decreases in hemoglobin levels result in further reduction in olfactory function. Objective This study examined the effects of iron-deficiency anemia (IDA) on olfactory function. Method The study enrolled 50 IDA patients and 50 healthy subjects. Olfactory function was evaluated using the Sniffin' Sticks olfactory test. The diagnosis of IDA was made according to World Health Organization (WHO) criteria. Results Patients with IDA had a significantly lower threshold, discrimination, and identification (TDI) value, and a lower threshold compared with the control group. However, there were no significant differences between the groups in terms of smell selectivity values.

  12. Profiling of Olfactory Receptor Gene Expression in Whole Human Olfactory Mucosa

    PubMed Central

    Tarabichi, Maxime; Gregoire, Françoise; Dumont, Jacques E.; Chatelain, Pierre

    2014-01-01

    Olfactory perception is mediated by a large array of olfactory receptor genes. The human genome contains 851 olfactory receptor gene loci. More than 50% of the loci are annotated as nonfunctional due to frame-disrupting mutations. Furthermore haplotypic missense alleles can be nonfunctional resulting from substitution of key amino acids governing protein folding or interactions with signal transduction components. Beyond their role in odor recognition, functional olfactory receptors are also required for a proper targeting of olfactory neuron axons to their corresponding glomeruli in the olfactory bulb. Therefore, we anticipate that profiling of olfactory receptor gene expression in whole human olfactory mucosa and analysis in the human population of their expression should provide an opportunity to select the frequently expressed and potentially functional olfactory receptors in view of a systematic deorphanization. To address this issue, we designed a TaqMan Low Density Array (Applied Biosystems), containing probes for 356 predicted human olfactory receptor loci to investigate their expression in whole human olfactory mucosa tissues from 26 individuals (13 women, 13 men; aged from 39 to 81 years, with an average of 67±11 years for women and 63±12 years for men). Total RNA isolation, DNase treatment, RNA integrity evaluation and reverse transcription were performed for these 26 samples. Then 384 targeted genes (including endogenous control genes and reference genes specifically expressed in olfactory epithelium for normalization purpose) were analyzed using the same real-time reverse transcription PCR platform. On average, the expression of 273 human olfactory receptor genes was observed in the 26 selected whole human olfactory mucosa analyzed, of which 90 were expressed in all 26 individuals. Most of the olfactory receptors deorphanized to date on the basis of sensitivity to known odorant molecules, which are described in the literature, were found in the

  13. Olfactory neuroblastoma: A case report

    PubMed Central

    USLU, GONCA HANEDAN; CANYILMAZ, EMINE; ZENGIN, AHMET YASAR; MUNGAN, SEVDEGUL; YONEY, ADNAN; BAHADIR, OSMAN; GOCMEZ, HUSEYIN

    2015-01-01

    Olfactory neuroblastoma (ON) is a rare type of malignant neoplasm originating from the olfactory neuroepithelial cells of the nasal cavity. ON is also known as esthesioneuroblastoma or neuroendocrine carcinoma. The malignancy accounts for <3% of tumors originating in the nasal cavity. Through the nasal cavity, ON may infiltrate the sinuses, the orbit and the cranium. The tumor is characterized by a pattern of slow growth and local recurrences. Treatment options are surgical excision or surgery combined with a radiotherapy (RT) and/or chemotherapy combination treatment. The present study reports the case of a 69-year-old patient with a mass in the nasal cavity who was treated by combined surgical excision and RT. The literature for ON and the treatment of the tumor are also discussed. PMID:26788185

  14. Linking local circuit inhibition to olfactory behavior: a critical role for granule cells in olfactory discrimination.

    PubMed

    Strowbridge, Ben W

    2010-02-11

    In this issue of Neuron, Abraham et al. report a direct connection between inhibitory function and olfactory behavior. Using molecular methods to alter glutamate receptor subunit composition in olfactory bulb granule cells, the authors found a selective modulation in the time required for difficult, but not simple, olfactory discrimination tasks.

  15. Role of Centrifugal Projections to the Olfactory Bulb in Olfactory Processing

    ERIC Educational Resources Information Center

    Kiselycznyk, Carly L.; Zhang, Steven; Linster, Christine

    2006-01-01

    While there is evidence that feedback projections from cortical and neuromodulatory structures to the olfactory bulb are crucial for maintaining the oscillatory dynamics of olfactory bulb processing, it is not clear how changes in dynamics are related to odor perception. Using electrical lesions of the olfactory peduncle, sparing output from the…

  16. Role of Centrifugal Projections to the Olfactory Bulb in Olfactory Processing

    ERIC Educational Resources Information Center

    Kiselycznyk, Carly L.; Zhang, Steven; Linster, Christine

    2006-01-01

    While there is evidence that feedback projections from cortical and neuromodulatory structures to the olfactory bulb are crucial for maintaining the oscillatory dynamics of olfactory bulb processing, it is not clear how changes in dynamics are related to odor perception. Using electrical lesions of the olfactory peduncle, sparing output from the…

  17. Morphological and molecular features of the mammalian olfactory sensory neuron axons: What makes these axons so special?

    PubMed

    Nedelec, Stéphane; Dubacq, Caroline; Trembleau, Alain

    2005-03-01

    The main organization and gross morphology of the mammalian olfactory primary pathway, from the olfactory epithelium to the olfactory bulb, has been initially characterized using classical anatomical and ultrastructural approaches. During the last fifteen years, essentially thanks to the cloning of the odorant receptor genes, and to the characterization of a number of molecules expressed by the olfactory sensory neuron axons and their environment, significant new insights have been gained into the understanding of the development and adult functioning of this system. In the course of these genetic, biochemical and neuroanatomical studies, however, several molecular and structural features were uncovered that appear somehow to be unique to these axons. For example, these axons express odorant receptors in their terminal segment, and transport several mRNA species and at least two transcription factors. In the present paper, we review these unusual structural and molecular features and speculate about their possible functions in the development and maintenance of the olfactory system.

  18. Insect density-plant density relationships: a modified view of insect responses to resource concentrations.

    PubMed

    Andersson, Petter; Löfstedt, Christer; Hambäck, Peter A

    2013-12-01

    Habitat area is an important predictor of spatial variation in animal densities. However, the area often correlates with the quantity of resources within habitats, complicating our understanding of the factors shaping animal distributions. We addressed this problem by investigating densities of insect herbivores in habitat patches with a constant area but varying numbers of plants. Using a mathematical model, predictions of scale-dependent immigration and emigration rates for insects into patches with different densities of host plants were derived. Moreover, a field experiment was conducted where the scaling properties of odour-mediated attraction in relation to the number of odour sources were estimated, in order to derive a prediction of immigration rates of olfactory searchers. The theoretical model predicted that we should expect immigration rates of contact and visual searchers to be determined by patch area, with a steep scaling coefficient, μ = -1. The field experiment suggested that olfactory searchers should show a less steep scaling coefficient, with μ ≈ -0.5. A parameter estimation and analysis of published data revealed a correspondence between observations and predictions, and density-variation among groups could largely be explained by search behaviour. Aphids showed scaling coefficients corresponding to the prediction for contact/visual searchers, whereas moths, flies and beetles corresponded to the prediction for olfactory searchers. As density responses varied considerably among groups, and variation could be explained by a certain trait, we conclude that a general theory of insect responses to habitat heterogeneity should be based on shared traits, rather than a general prediction for all species.

  19. Human olfactory receptor responses to odorants

    PubMed Central

    Mainland, Joel D; Li, Yun R; Zhou, Ting; Liu, Wen Ling L; Matsunami, Hiroaki

    2015-01-01

    Although the human olfactory system is capable of discriminating a vast number of odors, we do not currently understand what chemical features are encoded by olfactory receptors. In large part this is due to a paucity of data in a search space covering the interactions of hundreds of receptors with billions of odorous molecules. Of the approximately 400 intact human odorant receptors, only 10% have a published ligand. Here we used a heterologous luciferase assay to screen 73 odorants against a clone library of 511 human olfactory receptors. This dataset will allow other researchers to interrogate the combinatorial nature of olfactory coding. PMID:25977809

  20. An argument for an olfactory thalamus.

    PubMed

    Kay, Leslie M; Sherman, S Murray

    2007-02-01

    The mammalian olfactory system is unique in that sensory receptors synapse directly into the olfactory bulb of the forebrain without the thalamic relay that is common to all other sensory pathways. We argue that the olfactory bulb has an equivalent role to the thalamus, because the two regions have very similar structures and functions. Both the thalamus and the olfactory bulb are the final stage in sensory processing before reaching target cortical regions, at which there is a massive increase in neuron and synapse numbers. Thus, both structures act as a bottleneck that is a target for various modulatory inputs, and this arrangement enables efficient control of information flow before cortical processing occurs.

  1. A natural polymorphism alters odour and DEET sensitivity in an insect odorant receptor.

    PubMed

    Pellegrino, Maurizio; Steinbach, Nicole; Stensmyr, Marcus C; Hansson, Bill S; Vosshall, Leslie B

    2011-09-21

    Blood-feeding insects such as mosquitoes are efficient vectors of human infectious diseases because they are strongly attracted by body heat, carbon dioxide and odours produced by their vertebrate hosts. Insect repellents containing DEET (N,N-diethyl-meta-toluamide) are highly effective, but the mechanism by which this chemical wards off biting insects remains controversial despite decades of investigation. DEET seems to act both at close range as a contact chemorepellent, by affecting insect gustatory receptors, and at long range, by affecting the olfactory system. Two opposing mechanisms for the observed behavioural effects of DEET in the gas phase have been proposed: that DEET interferes with the olfactory system to block host odour recognition and that DEET actively repels insects by activating olfactory neurons that elicit avoidance behaviour. Here we show that DEET functions as a modulator of the odour-gated ion channel formed by the insect odorant receptor complex. The functional insect odorant receptor complex consists of a common co-receptor, ORCO (ref. 15) (formerly called OR83B; ref. 16), and one or more variable odorant receptor subunits that confer odour selectivity. DEET acts on this complex to potentiate or inhibit odour-evoked activity or to inhibit odour-evoked suppression of spontaneous activity. This modulation depends on the specific odorant receptor and the concentration and identity of the odour ligand. We identify a single amino-acid polymorphism in the second transmembrane domain of receptor OR59B in a Drosophila melanogaster strain from Brazil that renders OR59B insensitive to inhibition by the odour ligand and modulation by DEET. Our data indicate that natural variation can modify the sensitivity of an odour-specific insect odorant receptor to odour ligands and DEET. Furthermore, they support the hypothesis that DEET acts as a molecular 'confusant' that scrambles the insect odour code, and provide a compelling explanation for the broad

  2. Insect-ual Pursuits.

    ERIC Educational Resources Information Center

    Mallow, David

    1991-01-01

    Explains how insects can be used to stimulate student writing. Describes how students can create their own systems to classify and differentiate insects. Discusses insect morphology and includes three detailed diagrams. The author provides an extension activity where students hypothesize about the niche of an insect based on its anatomy. (PR)

  3. Insect-ual Pursuits.

    ERIC Educational Resources Information Center

    Mallow, David

    1991-01-01

    Explains how insects can be used to stimulate student writing. Describes how students can create their own systems to classify and differentiate insects. Discusses insect morphology and includes three detailed diagrams. The author provides an extension activity where students hypothesize about the niche of an insect based on its anatomy. (PR)

  4. Book Review: Insect Virology

    USDA-ARS?s Scientific Manuscript database

    Viruses that infect insects have long been of interest both as a means for controlling insect pest populations in an environmentally safe manner, and also as significant threats to beneficial insects of great value, such as honey bees and silkworms. Insect viruses also have been of intrinsic intere...

  5. Morphological and behavioural changes occur following the X-ray irradiation of the adult mouse olfactory neuroepithelium

    PubMed Central

    2012-01-01

    Background The olfactory neuroepithelium lines the upper nasal cavity and is in direct contact with the external environment and the olfactory bulbs. The ability to self-renew throughout life and the reproducible recovery after injury, make it a model tissue to study mechanisms underlying neurogenesis. In this study, X-rays were used to disrupt proliferating olfactory stem cell populations and to assess their role in the cellular and morphological changes involved in olfactory neurogenic processes. Results We have analysed the histological and functional effects of a sub-lethal dose of X-rays on the adult mouse olfactory neuroepithelium at 2 hours, 24 hours, 1 week, 2 weeks and 5 weeks. We have shown an immediate cessation of proliferating olfactory stem cells as shown by BrdU, Ki67 and pH3 expression. At 24 hours there was an increase in the neural transcription factors Mash1 and Pax6 expression, and a disruption of the basal lamina and increase in glandular cell marker expression at 1 week post-irradiation. Coincident with these changes was an impairment of the olfactory function in vivo. Conclusions We have shown significant changes in basal cell proliferation as well as morphological changes in the olfactory neuroepithelium following X-ray irradiation. There is involvement of the basal lamina as well as a clear role for glandular and sustentacular cells. PMID:23113950

  6. Molecule capture by olfactory antennules: mantis shrimp.

    PubMed

    Stacey, Mark T; Mead, Kristina S; Koehl, Mimi A R

    2002-01-01

    A critical step in the process of olfaction is the movement of odorant molecules from the environment to the surface of a chemosensory structure. Many marine crustaceans capture odorant molecules with arrays of chemosensory sensilla (aesthetascs) on antennules that they flick through the water. We developed a model to calculate molecule flux to the surfaces of aesthetascs in order to study how the size, aesthetasc spacing, and flick kinematics of olfactory antennules affect their performance in capturing molecules from the surrounding water. Since the three-dimensional geometry of an aesthetasc-bearing antennule is complex, dynamically-scaled physical models can often provide an efficient method of determining the fluid velocity field through the array. Here we present a method to optimize the incorporation of such measured velocity vector fields into a numerical simulation of the advection and diffusion of odorants to aesthetasc surfaces. Furthermore, unlike earlier models of odorant interception by antennae, our model incorporates odorant concentration distributions that have been measured in turbulent ambient flows. By applying our model to the example of the olfactory antennules of mantis shrimp, we learned that flicking velocity can have profound effects on odorant flux to the aesthetascs if they operate in the speed range in which the leakiness of the gaps between the aesthetascs to fluid movement is sensitive to velocity. This sensitivity creates an asymmetry in molecule fluxes between outstroke and return stroke, which results in an antennule taking discrete samples in space and time, i.e. "sniffing". As stomatopods grow and their aesthetasc Reynolds number increases, the aesthetasc arrangement on the antennule changes in a way that maintains these asymmetries in leakiness and molecule flux between the outstroke and return stroke, allowing the individual to continue to take discrete samples as it develops.

  7. Appetitive associative olfactory learning in Drosophila larvae.

    PubMed

    Apostolopoulou, Anthi A; Widmann, Annekathrin; Rohwedder, Astrid; Pfitzenmaier, Johanna E; Thum, Andreas S

    2013-02-18

    In the following we describe the methodological details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with genetic interference, provides a handle to analyze the neuronal and molecular fundamentals of specifically associative learning in a simple larval brain. Organisms can use past experience to adjust present behavior. Such acquisition of behavioral potential can be defined as learning, and the physical bases of these potentials as memory traces. Neuroscientists try to understand how these processes are organized in terms of molecular and neuronal changes in the brain by using a variety of methods in model organisms ranging from insects to vertebrates. For such endeavors it is helpful to use model systems that are simple and experimentally accessible. The Drosophila larva has turned out to satisfy these demands based on the availability of robust behavioral assays, the existence of a variety of transgenic techniques and the elementary organization of the nervous system comprising only about 10,000 neurons (albeit with some concessions: cognitive limitations, few behavioral options, and richness of experience questionable). Drosophila larvae can form associations between odors and appetitive gustatory reinforcement like sugar. In a standard assay, established in the lab of B. Gerber, animals receive a two-odor reciprocal training: A first group of larvae is exposed to an odor A together with a gustatory reinforcer (sugar reward) and is subsequently exposed to an odor B without reinforcement. Meanwhile a second group of larvae receives reciprocal training while experiencing odor A without reinforcement and subsequently being exposed to odor B with reinforcement (sugar reward). In the following both groups are tested for their preference between the two odors. Relatively higher preferences for the rewarded odor reflect associative learning--presented as a performance index (PI). The conclusion regarding the associative

  8. Evidence for partial overlap of male olfactory cues in lampreys.

    PubMed

    Buchinger, Tyler J; Li, Ke; Huertas, Mar; Baker, Cindy F; Jia, Liang; Hayes, Michael C; Li, Weiming; Johnson, Nicholas S

    2017-02-01

    Animals rely on a mosaic of complex information to find and evaluate mates. Pheromones, often consisting of multiple components, are considered to be particularly important for species-recognition in many species. Although the evolution of species-specific pheromone blends is well described in many insects, very few vertebrate pheromones have been studied in a macro-evolutionary context. Here, we report a phylogenetic comparison of multi-component male odours that guide reproduction in lampreys. Chemical profiling of sexually mature males from eleven species of lamprey, representing six of ten genera and two of three families, indicated that the chemical profiles of sexually mature male odours are partially shared among species. Behavioural assays conducted with four species sympatric in the Laurentian Great Lakes indicated asymmetric female responses to heterospecific odours, where Petromyzon marinus were attracted to male odour collected from all species tested, but other species generally preferred only the odour of conspecifics. Electro-olfactogram recordings from P. marinus indicated that although P. marinus exhibited behavioural responses to odours from males of all species, at least some of the compounds that elicited olfactory responses were different in conspecific male odours compared with heterospecific male odours. We conclude that some of the compounds released by sexually mature males are shared among species and elicit olfactory and behavioural responses in P. marinus, and suggest that our results provide evidence for partial overlap of male olfactory cues among lampreys. Further characterization of the chemical identities of odour components is needed to confirm shared pheromones among species. © 2017. Published by The Company of Biologists Ltd.

  9. On the Origin and Evolution of Vertebrate Olfactory Receptor Genes: Comparative Genome Analysis Among 23 Chordate Species

    PubMed Central

    2009-01-01

    Olfaction is a primitive sense in organisms. Both vertebrates and insects have receptors for detecting odor molecules in the environment, but the evolutionary origins of these genes are different. Among studied vertebrates, mammals have ∼1,000 olfactory receptor (OR) genes, whereas teleost fishes have much smaller (∼100) numbers of OR genes. To investigate the origin and evolution of vertebrate OR genes, I attempted to determine near-complete OR gene repertoires by searching whole-genome sequences of 14 nonmammalian chordates, including cephalochordates (amphioxus), urochordates (ascidian and larvacean), and vertebrates (sea lamprey, elephant shark, five teleost fishes, frog, lizard, and chicken), followed by a large-scale phylogenetic analysis in conjunction with mammalian OR genes identified from nine species. This analysis showed that the amphioxus has >30 vertebrate-type OR genes though it lacks distinctive olfactory organs, whereas all OR genes appear to have been lost in the urochordate lineage. Some groups of genes (θ, κ, and λ) that are phylogenetically nested within vertebrate OR genes showed few gene gains and losses, which is in sharp contrast to the evolutionary pattern of OR genes, suggesting that they are actually non-OR genes. Moreover, the analysis demonstrated a great difference in OR gene repertoires between aquatic and terrestrial vertebrates, reflecting the necessity for the detection of water-soluble and airborne odorants, respectively. However, a minor group (β) of genes that are atypically present in both aquatic and terrestrial vertebrates was also found. These findings should provide a critical foundation for further physiological, behavioral, and evolutionary studies of olfaction in various organisms. PMID:20333175

  10. Introducing Computational Fluid Dynamics Simulation into Olfactory Display

    NASA Astrophysics Data System (ADS)

    Ishida, Hiroshi; Yoshida, Hitoshi; Nakamoto, Takamichi

    An olfactory display is a device that delivers various odors to the user's nose. It can be used to add special effects to movies and games by releasing odors relevant to the scenes shown on the screen. In order to provide high-presence olfactory stimuli to the users, the display must be able to generate realistic odors with appropriate concentrations in a timely manner together with visual and audio playbacks. In this paper, we propose to use computational fluid dynamics (CFD) simulations in conjunction with the olfactory display. Odor molecules released from their source are transported mainly by turbulent flow, and their behavior can be extremely complicated even in a simple indoor environment. In the proposed system, a CFD solver is employed to calculate the airflow field and the odor dispersal in the given environment. An odor blender is used to generate the odor with the concentration determined based on the calculated odor distribution. Experimental results on presenting odor stimuli synchronously with movie clips show the effectiveness of the proposed system.

  11. Sensational placodes: Neurogenesis in the otic and olfactory systems

    PubMed Central

    Maier, Esther C.; Saxena, Ankur; Alsina, Berta; Bronner, Marianne E.; Whitfield, Tanya T.

    2014-01-01

    For both the intricate morphogenetic layout of the sensory cells in the ear and the elegantly radial arrangement of the sensory neurons in the nose, numerous signaling molecules and genetic determinants are required in concert to generate these specialized neuronal populations that help connect us to our environment. In this review, we outline many of the proteins and pathways that play essential roles in the differentiation of otic and olfactory neurons and their integration into their non-neuronal support structures. In both cases, well-known signaling pathways together with region-specific factors transform thickened ectodermal placodes into complex sense organs containing numerous, diverse neuronal subtypes. Olfactory and otic placodes, in combination with migratory neural crest stem cells, generate highly specialized subtypes of neuronal cells that sense sound, position and movement in space, odors and pheromones throughout our lives. PMID:24508480

  12. Beyond modeling: all-atom olfactory receptor model simulations.

    PubMed

    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.

  13. Induction of Associative Olfactory Memory by Targeted Activation of Single Olfactory Neurons in Drosophila Larvae

    PubMed Central

    Honda, Takato; Lee, Chi-Yu; Yoshida-Kasikawa, Maki; Honjo, Ken; Furukubo-Tokunaga, Katsuo

    2014-01-01

    It has been postulated that associative memory is formed by at least two sets of external stimuli, CS and US, that are transmitted to the memory centers by distinctive conversing pathways. However, whether associative memory can be induced by the activation of only the olfactory CS and a biogenic amine-mediated US pathways remains to be elucidated. In this study, we substituted the reward signals with dTrpA1-mediated thermogenetic activation of octopaminergic neurons and the odor signals by ChR2-mediated optical activation of a specific class of olfactory neurons. We show that targeted activation of the olfactory receptor and the octopaminergic neurons is indeed sufficient for the formation of associative olfactory memory in the larval brain. We also show that targeted stimulation of only a single type of olfactory receptor neurons is sufficient to induce olfactory memory that is indistinguishable from natural memory induced by the activation of multiple olfactory receptor neurons. PMID:24762789

  14. [Olfactory functional magnetic resonance imaging with modified OEP-98C olfactometer and event-related design].

    PubMed

    You, Hui; Wang, Jian; Liu, Jian-Feng; Feng, Feng; Ni, Dao-Feng; Jin, Zheng-Yu

    2009-04-01

    To explore the feasibility of functional magnetic resonance imaging (fMRI) in analysis of olfaction function with modified OEP-98C olfactometer and event-related design. Six young right-handed men underwent olfactory fMRI with event-related design. OEP-98C olfactometer was modified to accommodate MR environment. There were 2 types of tasks in the experiment. In one task, only isoamyl acetate was used as odorant. In the other task, to avoid possible decreased olfactory attention, vanillin was given before each presentation of isoamyl acetate. In both tasks, uniform activation in piriform cortex and secondary olfactory cortexes was determined. The activation of piriform cortex was not significantly different between the two tasks (P > 0.01). With isoamyl acetate as odorant, modified OEP-98C olfactometer, and event-related design, olfaction fMRI can depict cortex activation at primary and secondary olfactory cortex. Applying other odorant with similar quality to avoid olfactory attention decrease can not promote depiction of activation in primary olfactory cortex.

  15. Olfactory epithelium changes in germfree mice

    PubMed Central

    François, Adrien; Grebert, Denise; Rhimi, Moez; Mariadassou, Mahendra; Naudon, Laurent; Rabot, Sylvie; Meunier, Nicolas

    2016-01-01

    Intestinal epithelium development is dramatically impaired in germfree rodents, but the consequences of the absence of microbiota have been overlooked in other epithelia. In the present study, we present the first description of the bacterial communities associated with the olfactory epithelium and explored differences in olfactory epithelium characteristics between germfree and conventional, specific pathogen-free, mice. While the anatomy of the olfactory epithelium was not significantly different, we observed a thinner olfactory cilia layer along with a decreased cellular turn-over in germfree mice. Using electro-olfactogram, we recorded the responses of olfactory sensitive neuronal populations to various odorant stimulations. We observed a global increase in the amplitude of responses to odorants in germfree mice as well as altered responses kinetics. These changes were associated with a decreased transcription of most olfactory transduction actors and of olfactory xenobiotic metabolising enzymes. Overall, we present here the first evidence that the microbiota modulates the physiology of olfactory epithelium. As olfaction is a major sensory modality for most animal species, the microbiota may have an important impact on animal physiology and behaviour through olfaction alteration. PMID:27089944

  16. Microvasculature of the Olfactory Organ in the Japanese Monkey (Macaca fuscata fuscata)

    NASA Astrophysics Data System (ADS)

    Okada, Shigenori; Schraufnagel, Dean E.

    2002-06-01

    Olfaction is an important and primitive sense. As its importance has changed with evolution, anatomic adjustments have occurred in its structure and vasculature. Primates are a family of vertebrates that have had to develop their visual system to adapt to the arboreal environment and have evolved from a macrosmatic to a microsmatic species as the optic system has enlarged. This has resulted in anatomic changes of a small but critical area at the base of the brain. This paper describes the three-dimensional vascular anatomy of the olfactory organ of the Japanese monkey (Macaca fuscata fuscata). This is best understood by dividing the organ into three parts: the olfactory tract, olfactory bulb, and olfactory nerves in the nasal mucosa. The bulb can be partitioned into an outer or cortical part and inner or medullary part. The vasculature and tissue were examined grossly and with light microscopy and scanning electron microscopy of vascular corrosion casts. The olfactory tract and bulb were supplied by an arteriole from the anterior cerebral artery on each side. The tract was supplied by capillaries running spirally with a coarse network. At the olfactory bulb, the arteriole ramified into the intracortical and medullary branches that formed capillary networks. The bulbar intracortical capillaries were divided into two layers with different densities and vascular patterns. The capillaries of the superficial layer had a ladder-like pattern. The branches that ran into the medulla of the olfactory bulb were more widely spaced. Twigs from the posterior ethmoidal artery ran along the nerve fiber and formed intra- and extrafascicular networks. Each region of the olfactory organ had characteristic three-dimensional vascular patterns that were related to their cellular architecture.

  17. Nasal gel and olfactory cleft.

    PubMed

    Herranz González-Botas, Jesús; Padín Seara, Anselmo

    2012-01-01

    To evaluate whether a nasal gel, administrated using a radial-hole inhaler, reaches the olfactory cleft and if a different administration method influences distribution. Sixteen healthy volunteers underwent a nasal endoscopy at 1 and 7minutes after the administration of a intranasal gel, with a different method in each fossa. No dye deposition was identified at the olfactory cleft, middle turbinate or middle meatus. In all cases the gel was identified at the nasal vestibule. On the right side, the second most frequent dye identification area was the inferior turbinate, with a rate of 87% at the first minute and 75% at 7 minutes. It was followed by the septum (75 and 62%) and the inferior meatus (6.2 and 12.5%). On the left side, the second most frequent stained area was the septum (18.7 and 13.5%), followed by the inferior meatus (6.5 and 65%). No inferior turbinate staining was found in the left side. There was a significant difference in the deposition rate at the septum (P<.01) and inferior turbinate (P<.001), when both administration methods were compared. No nasal gel, administrated using a radial-hole inhaler, was found at the olfactory cleft, middle turbinate or middle meatus. Gel distribution was located at the anterior and inferior portion of the nose, independent of the administration method used. Significantly different gel distribution rates were found at the septum and inferior turbinate when the 2 administration methods were compared. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  18. Differential response of olfactory sensory neuron populations to copper ion exposure in zebrafish.

    PubMed

    Lazzari, Maurizio; Bettini, Simone; Milani, Liliana; Maurizii, Maria Gabriella; Franceschini, Valeria

    2017-02-01

    The peripheral olfactory system of fish is in direct contact with the external aqueous environment, so dissolved contaminants can easily impair sensory functions and cause neurobehavioral injuries. The olfactory epithelium of fish is arranged in lamellae forming a rosette in the olfactory cavity and contains three main types of olfactory sensory neurons (OSNs): ciliated (cOSNs) and microvillous olfactory sensory neurons (mOSNs), common to all vertebrates, and a third minor group of olfactory neurons, crypt cells, absent in tetrapods. Since copper is a ubiquitously diffusing olfactory toxicant and a spreading contaminant in urban runoff, we investigated the effect of low copper concentration on the three different OSNs in the olfactory epithelium of zebrafish, a model system widely used in biological research. Image analysis was applied for morphometry and quantification of immunohistochemically detected OSNs. Copper exposure resulted in an evident decrease in olfactory epithelium thickness. Moreover, after exposure, the lamellae of the dorsal and ventral halves of the olfactory rosettes showed a different increase in their sensory areas, suggesting a lateral migration of new cells into non-sensory regions. The results of the present study provide clear evidence of a differential response of the three neural cell populations of zebrafish olfactory mucosa after 96h of exposure to copper ions at the sublethal concentration of 30μgL(-1). Densitometric values of cONS, immunostained with anti-G αolf, decreased of about 60% compared to the control. When the fish were transferred to water without copper addition and examined after 3, 10 and 30days, we observed a partial restoration of anti-G αolf staining intensity to normal condition. The recovery of cOSNs appeared sustained by neuronal proliferation, quantified with anti-PCNA immunostaining, in particular in the early days after exposure. The densitometric analysis applied to mOSNs, immunostained with anti-TRPC2

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

    USDA-ARS?s Scientific Manuscript database

    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...

  20. Male- and female-biased gene expression of olfactory-related genes in the antennae of Asian corn borer, Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae)

    USDA-ARS?s Scientific Manuscript database

    The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), is a destructive pest insect of cultivated corn crops, for which antennal-expressed receptors are important to detect olfactory cues for mate attraction and oviposition. Non-normalized male and female O. furnacalis antennal cDNA libraries we...

  1. Calcium signals in olfactory neurons.

    PubMed

    Tareilus, E; Noé, J; Breer, H

    1995-11-09

    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.

  2. Drosophila's view on insect vision.

    PubMed

    Borst, Alexander

    2009-01-13

    Within the last 400 million years, insects have radiated into at least a million species, accounting for more than half of all known living organisms: they are the most successful group in the animal kingdom, found in almost all environments of the planet, ranging in body size from a mere 0.1 mm up to half a meter. Their eyes, together with the respective parts of the nervous system dedicated to the processing of visual information, have long been the subject of intense investigation but, with the exception of some very basic reflexes, it is still not possible to link an insect's visual input to its behavioral output. Fortunately for the field, the fruit fly Drosophila is an insect, too. This genetic workhorse holds great promise for the insect vision field, offering the possibility of recording, suppressing or stimulating any single neuron in its nervous system. Here, I shall give a brief synopsis of what we currently know about insect vision, describe the genetic toolset available in Drosophila and give some recent examples of how the application of these tools have furthered our understanding of color and motion vision in Drosophila.

  3. Odourant dominance in olfactory mixture processing: what makes a strong odourant?

    PubMed

    Schubert, Marco; Sandoz, Jean-Christophe; Galizia, Giovanni; Giurfa, Martin

    2015-03-07

    The question of how animals process stimulus mixtures remains controversial as opposing views propose that mixtures are processed analytically, as the sum of their elements, or holistically, as unique entities different from their elements. Overshadowing is a widespread phenomenon that can help decide between these alternatives. In overshadowing, an individual trained with a binary mixture learns one element better at the expense of the other. Although element salience (learning success) has been suggested as a main explanation for overshadowing, the mechanisms underlying this phenomenon remain unclear. We studied olfactory overshadowing in honeybees to uncover the mechanisms underlying olfactory-mixture processing. We provide, to our knowledge, the most comprehensive dataset on overshadowing to date based on 90 experimental groups involving more than 2700 bees trained either with six odourants or with their resulting 15 binary mixtures. We found that bees process olfactory mixtures analytically and that salience alone cannot predict overshadowing. After normalizing learning success, we found that an unexpected feature, the generalization profile of an odourant, was determinant for overshadowing. Odourants that induced less generalization enhanced their distinctiveness and became dominant in the mixture. Our study thus uncovers features that determine odourant dominance within olfactory mixtures and allows the referring of this phenomenon to differences in neural activity both at the receptor and the central level in the insect nervous system.

  4. The short neuropeptide F modulates olfactory sensitivity of Bactrocera dorsalis upon starvation.

    PubMed

    Jiang, Hong-Bo; Gui, Shun-Hua; Xu, Li; Pei, Yu-Xia; Smagghe, Guy; Wang, Jin-Jun

    2017-05-01

    The insect short neuropeptide F (sNPF) family has been shown to modulate diverse physiological processes, such as feeding, appetitive olfactory behavior, locomotion, sleep homeostasis and hormone release. In this study, we identified the sNPF (BdsNPF) and its receptor (BdsNPFR) in an important agricultural pest, the oriental fruit fly Bactrocera dorsalis (Hendel). Afterwards, the receptor cDNA was functionally expressed in Chinese hamster ovary cell lines. Activation of BdsNPFR by sNPF peptides caused an increase in intracellular calcium ions, with a 50% effective concentration values at the nanomolar level. As indicated by qPCR, the BdsNPF and BdsNPFR transcripts were mainly detected in the central nervous system and antennae, and they showed significantly starvation-induced expression patterns. Furthermore, we found that the starved flies had an increased electroantennogram response compared to the normally fed flies. However, this enhanced olfactory sensitivity was reversed when we decreased the expression of BdsNPF by double-stranded RNA injection in adults. We concluded that sNPF plays an important role in modulating the olfactory sensitivity of B. dorsalis upon starvation. Our results will facilitate the understanding of the regulation of early olfactory processing in B. dorsalis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. 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 host animal. PMID:26306800

  6. Olfactory experience shapes the evaluation of odour similarity in ants: a behavioural and computational analysis

    PubMed Central

    Perez, Margot; Nowotny, Thomas; d'Ettorre, Patrizia

    2016-01-01

    Perceptual similarity between stimuli is often assessed via generalization, the response to stimuli that are similar to the one which was previously conditioned. Although conditioning procedures are variable, studies on how this variation may affect perceptual similarity remain scarce. Here, we use a combination of behavioural and computational analyses to investigate the influence of olfactory conditioning procedures on odour generalization in ants. Insects were trained following either absolute conditioning, in which a single odour (an aldehyde) was rewarded with sucrose, or differential conditioning, in which one odour (the same aldehyde) was similarly rewarded and another odour (an aldehyde differing in carbon-chain length) was punished with quinine. The response to the trained odours and generalization to other aldehydes were assessed. We show that olfactory similarity, rather than being immutable, varies with the conditioning procedure. Compared with absolute conditioning, differential conditioning enhances olfactory discrimination. This improvement is best described by a multiplicative interaction between two independent processes, the excitatory and inhibitory generalization gradients induced by the rewarded and the punished odour, respectively. We show that olfactory similarity is dramatically shaped by an individual's perceptual experience and suggest a new hypothesis for the nature of stimulus interactions underlying experience-dependent changes in perceptual similarity. PMID:27581883

  7. 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.

  8. Ground plan of the insect mushroom body: functional and evolutionary implications

    PubMed Central

    Sinakevitch, Irina; Brown, Sheena M.

    2014-01-01

    In most insects with olfactory glomeruli, each side of the brain possesses a mushroom body equipped with calyces supplied by olfactory projection neurons. Kenyon cells providing dendrites to the calyces supply a pedunculus and lobes divided into subdivisions supplying outputs to other brain areas. It is with reference to these components that most functional studies are interpreted. However, mushroom body structures are diverse, adapted to different ecologies and likely to serve various functions. In insects whose derived life styles preclude the detection of airborne odorants there is a loss of the antennal lobes and attenuation or loss of the calyces. Such taxa retain mushroom body lobes that as elaborate as those of mushroom bodies equipped with calyces. Antennal lobe loss and calycal regression also typifies taxa with short non-feeding adults where olfaction is redundant. Examples are cicadas and mayflies, the latter representing the most basal lineage of winged insects. Mushroom bodies of another basal taxon, the Odonata, possess a remnant calyx that may reflect the visual ecology of this group. That mushroom bodies persist in brains of secondarily anosmic insects suggests that they play roles in higher functions other than olfaction. Mushroom bodies are not ubiquitous: the most basal living insects, the wingless Archaeognatha, possess glomerular antennal lobes but lack mushroom bodies, suggesting that the ability to process airborne odorants preceded the acquisition of mushroom bodies. Archaeognathan brains are like those of higher malacostracans, which lack mushroom bodies but have elaborate olfactory centers laterally in the brain. PMID:19152379

  9. Intravenous olfactory test latency correlates with improvement in post-infectious olfactory dysfunction.

    PubMed

    Horikiri, Kyohei; Kikuta, Shu; Kanaya, Kaori; Shimizu, Yuya; Nishijima, Hironobu; Yamasoba, Tatsuya; Kondo, Kenji

    2017-10-01

    This cohort study showed that onset latency in the intravenous olfactory test (IVO) may help predict when olfaction in patients with post-infectious olfactory dysfunction (PIOD) improves. To identify factors that predict the olfactory improvement period in patients with PIOD. All consecutive patients presenting with PIOD in 1994-2014 who were followed up for 2 years were identified retrospectively. The ability of demographic/clinical factors (age, sex, body mass index, presence/absence of allergic rhinitis, treatment/non-treatment with herbal medicines, patient dependence on herbal medicine treatment, presence/absence of diabetes mellitus, and smoking status) and olfactory test factors (response/no response and onset latency and duration in the IVO test, and detection and recognition scores on the T&T olfactory test) to predict the olfactory improvement period (defined respectively as the time from PIOD onset or olfactory testing to the first self-report of olfaction improvement) was analyzed by univariate and multivariate regression. Of the 187 PIOD patients, the prognostic ability of demographic/clinical factors was analyzed in 65. None predicted the olfactory improvement period. Of the 65 patients, 20 did not respond in the IVO test. In the remaining 45 patients, onset latency (but not the other olfactory test factors) was a significant prognosticator of olfactory improvement period (R(2)=0.24, p = 0.003).

  10. A Closer Look at Acid-Base Olfactory Titrations

    ERIC Educational Resources Information Center

    Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

    2005-01-01

    Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

  11. A Closer Look at Acid-Base Olfactory Titrations

    ERIC Educational Resources Information Center

    Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

    2005-01-01

    Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

  12. 21 CFR 874.1600 - Olfactory test device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1600 Olfactory test device. (a) Identification. An olfactory test device is used to determine whether an olfactory loss is present. The device... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Olfactory test device. 874.1600 Section...

  13. 21 CFR 874.1600 - Olfactory test device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1600 Olfactory test device. (a) Identification. An olfactory test device is used to determine whether an olfactory loss is present. The device... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Olfactory test device. 874.1600 Section...

  14. Detection of Olfactory Dysfunction Using Olfactory Event Related Potentials in Young Patients with Multiple Sclerosis

    PubMed Central

    Caminiti, Fabrizia; De Salvo, Simona; De Cola, Maria Cristina; Russo, Margherita; Bramanti, Placido; Marino, Silvia; Ciurleo, Rosella

    2014-01-01

    Background Several studies reported olfactory dysfunction in patients with multiple sclerosis. The estimate of the incidence of olfactory deficits in multiple sclerosis is uncertain; this may arise from different testing methods that may be influenced by patients' response bias and clinical, demographic and cognitive features. Aims To evaluate objectively the olfactory function using Olfactory Event Related Potentials. Materials and Methods We tested the olfactory function of 30 patients with relapsing remitting multiple sclerosis (mean age of 36.03±6.96 years) and of 30 age, sex and smoking–habit matched healthy controls by using olfactory potentials. A selective and controlled stimulation of the olfactory system to elicit the olfactory event related potentials was achieved by a computer-controlled olfactometer linked directly with electroencephalograph. Relationships between olfactory potential results and patients' clinical characteristics, such as gender, disability status score, disease-modifying therapy, and disease duration, were evaluated. Results Seven of 30 patients did not show olfactory event related potentials. Sixteen of remaining 23 patients had a mean value of amplitude significantly lower than control group (p<0.01). The presence/absence of olfactory event related potentials was associated with dichotomous expanded disability status scale (p = 0.0433), as well as inversely correlated with the disease duration (r = −0.3641, p = 0.0479). Conclusion Unbiased olfactory dysfunction of different severity found in multiple sclerosis patients suggests an organic impairment which could be related to neuroinflammatory and/or neurodegenerative processes of olfactory networks, supporting the recent findings on neurophysiopathology of disease. PMID:25047369

  15. Plants and insect eggs: how do they affect each other?

    PubMed

    Hilker, Monika; Meiners, Torsten

    2011-09-01

    Plant-insect interactions are not just influenced by interactions between plants and the actively feeding stages, but also by the close relationships between plants and insect eggs. Here, we review both effects of plants on insect eggs and, vice versa, effects of eggs on plants. We consider the influence of plants on the production of insect eggs and address the role of phytochemicals for the biosynthesis and release of insect sex pheromones, as well as for insect fecundity. Effects of plants on insect oviposition by contact and olfactory plant cues are summarised. In addition, we consider how the leaf boundary layer influences both insect egg deposition behaviour and development of the embryo inside the egg. The effects of eggs on plants involve egg-induced changes of photosynthetic activity and of the plant's secondary metabolism. Except for gall-inducing insects, egg-induced changes of phytochemistry were so far found to be detrimental to the eggs. Egg deposition can induce hypersensitive-like plant response, formation of neoplasms or production of ovicidal plant substances; these plant responses directly harm the eggs. In addition, egg deposition can induce a change of the plant's odour and leaf surface chemistry which serve indirect plant defence with the help of antagonists of the insect eggs. These egg-induced changes lead to attraction of egg parasitoids and their arrestance on a leaf, respectively. Finally, we summarise knowledge of the elicitors of egg-induced plant changes and address egg-induced effects on the plant's transcriptional pattern. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Caffeine and the olfactory bulb.

    PubMed

    Hadfield, M G

    1997-08-01

    Caffeine, a popular CNS stimulant, is the most widely used neuroactive drug. Present in coffee, tea, chocolate, and soft drinks as well as over-the-counter and prescription medications, it influences millions of users. This agent has achieved recent notoriety because its dependency consequences and addictive potential have been re-examined and emphasized. Caffeine's central actions are thought to be mediated through adenosine (A) receptors and monoamine neurotransmitters. The present article suggests that the olfactory bulb (OB) may be an important site in the brain that is responsible for caffeine's central actions in several species. This conclusion is based on the extraordinarily robust and selective effects of caffeine on norepinephrine (NE), dopamine (DA), and particularly serotonin (5HT) utilization in the OB of mice. We believe that these phenomena should be given appropriate consideration as a basis for caffeine's central actions, even in primates. Concurrently, we review a rich rodent literature concerned with A, 5HT, NE, and DA receptors in the OB and related structures along with other monoamine parameters. We also review a more limited literature concerned with the primate OB. Finally, we cite the literature that treats the dependency and addictive effects of caffeine in humans, and relate the findings to possible olfactory mechanisms.

  17. Retronasal odor representations in the dorsal olfactory bulb of rats

    PubMed Central

    Gautam, Shree Hari; Verhagen, Justus V.

    2012-01-01

    Animals perceive their olfactory environment not only from odors originating in the external world (orthonasal route) but also from odors released in the oral cavity while eating food (retronasal route). Retronasal olfaction is crucial for the perception of food flavor in humans. However, little is known about the retronasal stimulus coding in the brain. The most basic question is if and how route affects the odor representations at the level of the olfactory bulb (OB), where odor quality codes originate. We used optical calcium imaging of presynaptic dorsal OB responses to odorants in anesthetized rats to ask whether the rat OB could be activated retronasally, and how these responses compare to orthonasal responses under similar conditions. We further investigated the effects of specific odorant properties on orthoversus retronasal response patterns. We found that at a physiologically relevant flow rate retronasal odorants can effectively reach the olfactory receptor neurons, eliciting glomerular response patterns that grossly overlap with those of orthonasal responses, but differ from the orthonasal patterns in the response amplitude and temporal dynamics. Interestingly, such differences correlated well with specific odorant properties. Less volatile odorants yielded relatively smaller responses retronasally, but volatility did not affect relative temporal profiles. More polar odorants responded with relatively longer onset latency and time to peak retronasally, but polarity did not affect relative response magnitudes. These data provide insight into the early stages of retronasal stimulus coding and establish relationships between ortho- and retronasal odor representations in the rat OB. PMID:22674270

  18. San Francisco/Oakland Bay Bridge Welder Study: olfactory function.

    PubMed

    Antunes, Marcelo B; Bowler, Rosemarie; Doty, Richard L

    2007-09-18

    The sense of smell can be damaged by airborne xenobiotics, including aerosolized heavy metals, reflecting the direct exposure of its receptors to the outside environment. To determine whether professional welders working in confined spaces exhibit olfactory dysfunction. To determine whether such dysfunction, if present, is related to indices of metal exposure associated with welding, as well as measures of neurologic and neuropsychological function. The University of Pennsylvania Smell Identification Test (UPSIT) and a battery of neurologic and neuropsychological tests were administered to 43 welders who worked for 1 to 2 years on the San Francisco/Oakland Bay Bridge. Blood levels of Mn, Fe, Cu, and Pb were obtained. Relative to matched controls, the welders had significantly lower UPSIT scores, with a mean (SEM) of 29.51 (0.90) for welders and 36.55 (0.88) for controls. Eighty-eight percent scored below their individually matched controls. As in idiopathic Parkinson disease, the welders' olfactory test scores were unrelated to a broad spectrum of neurologic and neuropsychological test measures, as determined by principal components analysis. Although blood levels of Mn were associated with the time spent working on the bridge, workers with the highest Mn blood levels exhibited better olfactory function than those with the lowest Mn blood levels. The basis of this paradox, which has been observed previously, is unknown. Professional welders may be at risk for loss of smell function, although such loss seems to be unrelated to neurologic and neuropsychological test performance.

  19. Retronasal odor representations in the dorsal olfactory bulb of rats.

    PubMed

    Gautam, Shree Hari; Verhagen, Justus V

    2012-06-06

    Animals perceive their olfactory environment not only from odors originating in the external world (orthonasal route) but also from odors released in the oral cavity while eating food (retronasal route). Retronasal olfaction is crucial for the perception of food flavor in humans. However, little is known about the retronasal stimulus coding in the brain. The most basic questions are if and how route affects the odor representations at the level of the olfactory bulb (OB), where odor quality codes originate. We used optical calcium imaging of presynaptic dorsal OB responses to odorants in anesthetized rats to ask whether the rat OB could be activated retronasally, and how these responses compare to orthonasal responses under similar conditions. We further investigated the effects of specific odorant properties on orthonasal versus retronasal response patterns. We found that at a physiologically relevant flow rate, retronasal odorants can effectively reach the olfactory receptor neurons, eliciting glomerular response patterns that grossly overlap with those of orthonasal responses, but differ from the orthonasal patterns in the response amplitude and temporal dynamics. Interestingly, such differences correlated well with specific odorant properties. Less volatile odorants yielded relatively smaller responses retronasally, but volatility did not affect relative temporal profiles. More polar odorants responded with relatively longer onset latency and time to peak retronasally, but polarity did not affect relative response magnitudes. These data provide insight into the early stages of retronasal stimulus coding and establish relationships between orthonasal and retronasal odor representations in the rat OB.

  20. Preliminary Modeling and Simulation Study on Olfactory Cell Sensation

    SciTech Connect

    Zhou Jun; Chen Peihua; Liu Qingjun; Wang Ping; Yang Wei

    2009-05-23

    This paper introduced olfactory sensory neuron's whole-cell model with a concrete voltage-gated ionic channels and simulation. Though there are many models in olfactory sensory neuron and olfactory bulb, it remains uncertain how they express the logic of olfactory information processing. In this article, the olfactory neural network model is also introduced. This model specifies the connections among neural ensembles of the olfactory system. The simulation results of the neural network model are consistent with the observed olfactory biological characteristics such as 1/f-type power spectrum and oscillations.

  1. Insect olfaction from model systems to disease control

    PubMed Central

    Carey, Allison F.; Carlson, John R.

    2011-01-01

    Great progress has been made in the field of insect olfaction in recent years. Receptors, neurons, and circuits have been defined in considerable detail, and the mechanisms by which they detect, encode, and process sensory stimuli are being unraveled. We provide a guide to recent progress in the field, with special attention to advances made in the genetic model organism Drosophila. We highlight key questions that merit additional investigation. We then present our view of how recent advances may be applied to the control of disease-carrying insects such as mosquitoes, which transmit disease to hundreds of millions of people each year. We suggest how progress in defining the basic mechanisms of insect olfaction may lead to means of disrupting host-seeking and other olfactory behaviors, thereby reducing the transmission of deadly diseases. PMID:21746926

  2. Insects and Scorpions

    MedlinePlus

    ... Workplace Safety and Health Topics Insects & Scorpions Bees, Wasps, and Hornets Fire Ants Scorpions Additional Resources Hazards ... outdoor workers. Stinging or biting insects include bees, wasps, hornets, and fire ants. The health effects of ...

  3. Hearing in Insects.

    PubMed

    Göpfert, Martin C; Hennig, R Matthias

    2016-01-01

    Insect hearing has independently evolved multiple times in the context of intraspecific communication and predator detection by transforming proprioceptive organs into ears. Research over the past decade, ranging from the biophysics of sound reception to molecular aspects of auditory transduction to the neuronal mechanisms of auditory signal processing, has greatly advanced our understanding of how insects hear. Apart from evolutionary innovations that seem unique to insect hearing, parallels between insect and vertebrate auditory systems have been uncovered, and the auditory sensory cells of insects and vertebrates turned out to be evolutionarily related. This review summarizes our current understanding of insect hearing. It also discusses recent advances in insect auditory research, which have put forward insect auditory systems for studying biological aspects that extend beyond hearing, such as cilium function, neuronal signal computation, and sensory system evolution.

  4. Respiration in Aquatic Insects.

    ERIC Educational Resources Information Center

    MacFarland, John

    1985-01-01

    This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

  5. Insects: An Interdisciplinary Unit

    ERIC Educational Resources Information Center

    Leger, Heather

    2007-01-01

    The author talks about an interdisciplinary unit on insects, and presents activities that can help students practice communication skills (interpersonal, interpretive, and presentational) and learn about insects with hands-on activities.

  6. Ecophysiology and insect herbivory

    SciTech Connect

    Clancy, K.M.; Wagner, M.R.; Reich, P.B.

    1995-07-01

    The relationship of insect herbivory to conifer physiology is examined. Aspects of nutrient assimilation, nutrient distribution, water stress, and climatic change are correlated to defoliation by insects. Other factors examined include plant age, density, structure, soils, and plant genotype.

  7. Respiration in Aquatic Insects.

    ERIC Educational Resources Information Center

    MacFarland, John

    1985-01-01

    This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

  8. Molecular Characterization and Differential Expression of Olfactory Genes in the Antennae of the Black Cutworm Moth Agrotis ipsilon

    PubMed Central

    Gu, Shao-Hua; Sun, Liang; Yang, Ruo-Nan; Wu, Kong-Ming; Guo, Yu-Yuan; Li, Xian-Chun; Zhou, Jing-Jiang; Zhang, Yong-Jun

    2014-01-01

    Insects use their sensitive and selective olfactory system to detect outside chemical odorants, such as female sex pheromones and host plant volatiles. Several groups of olfactory proteins participate in the odorant detection process, including odorant binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs), ionotropic receptors (IRs) and sensory neuron membrane proteins (SNMPs). The identification and functional characterization of these olfactory proteins will enhance our knowledge of the molecular basis of insect chemoreception. In this study, we report the identification and differential expression profiles of these olfactory genes in the black cutworm moth Agrotis ipsilon. In total, 33 OBPs, 12 CSPs, 42 ORs, 24 IRs, 2 SNMPs and 1 gustatory receptor (GR) were annotated from the A. ipsilon antennal transcriptomes, and further RT-PCR and RT-qPCR revealed that 22 OBPs, 3 CSPs, 35 ORs, 14 IRs and the 2 SNMPs are uniquely or primarily expressed in the male and female antennae. Furthermore, one OBP (AipsOBP6) and one CSP (AipsCSP2) were exclusively expressed in the female sex pheromone gland. These antennae-enriched OBPs, CSPs, ORs, IRs and SNMPs were suggested to be responsible for pheromone and general odorant detection and thus could be meaningful target genes for us to study their biological functions in vivo and in vitro. PMID:25083706

  9. [Odor sensing system and olfactory display].

    PubMed

    Nakamoto, Takamichi

    2014-01-01

    In this review, an odor sensing system and an olfactory display are introduced into people in pharmacy. An odor sensing system consists of an array of sensors with partially overlapping specificities and pattern recognition technique. One of examples of odor sensing systems is a halitosis sensor which quantifies the mixture composition of three volatile sulfide compounds. A halitosis sensor was realized using a preconcentrator to raise sensitivity and an electrochemical sensor array to suppress the influence of humidity. Partial least squares (PLS) method was used to quantify the mixture composition. The experiment reveals that the sufficient accuracy was obtained. Moreover, the olfactory display, which present scents to human noses, is explained. A multi-component olfactory display enables the presentation of a variety of smells. The two types of multi-component olfactory display are described. The first one uses many solenoid valves with high speed switching. The valve ON frequency determines the concentration of the corresponding odor component. The latter one consists of miniaturized liquid pumps and a surface acoustic wave (SAW) atomizer. It enables the wearable olfactory display without smell persistence. Finally, the application of the olfactory display is demonstrated. Virtual ice cream shop with scents was made as a content of interactive art. People can enjoy harmony among vision, audition and olfaction. In conclusion, both odor sensing system and olfactory display can contribute to the field of human health care.

  10. Information processing in the mammalian olfactory system.

    PubMed

    Lledo, Pierre-Marie; Gheusi, Gilles; Vincent, Jean-Didier

    2005-01-01

    Recently, modern neuroscience has made considerable progress in understanding how the brain perceives, discriminates, and recognizes odorant molecules. This growing knowledge took over when the sense of smell was no longer considered only as a matter for poetry or the perfume industry. Over the last decades, chemical senses captured the attention of scientists who started to investigate the different stages of olfactory pathways. Distinct fields such as genetic, biochemistry, cellular biology, neurophysiology, and behavior have contributed to provide a picture of how odor information is processed in the olfactory system as it moves from the periphery to higher areas of the brain. So far, the combination of these approaches has been most effective at the cellular level, but there are already signs, and even greater hope, that the same is gradually happening at the systems level. This review summarizes the current ideas concerning the cellular mechanisms and organizational strategies used by the olfactory system to process olfactory information. We present findings that exemplified the high degree of olfactory plasticity, with special emphasis on the first central relay of the olfactory system. Recent observations supporting the necessity of such plasticity for adult brain functions are also discussed. Due to space constraints, this review focuses mainly on the olfactory systems of vertebrates, and primarily those of mammals.

  11. Olfactory Behavioral Testing in the Adult Mouse

    PubMed Central

    M. Witt, Rochelle; M. Galligan, Meghan; R. Despinoy, Jennifer; Segal, Rosalind

    2009-01-01

    The rodent olfactory system is of increasing interest to scientists, studied, in part, in systems biology because of its stereotyped, yet accessible circuitry. In addition, this area's unique ability to generate new neurons throughout an organism's lifetime makes it an attractive system for developmental and regenerative biologists alike. Such interest necessitates a means for a quick, yet reliable assessment of olfactory function. Many tests of olfactory ability are complex, variable or not specifically designed for mice. Also, some tests are sensitive to memory deficits as well as defects in olfactory abilities, confounding obtained results. Here, we describe a simple battery of tests designed to identify defects in olfactory sensitivity and preference. First, an initial general health assessment allows for the identification of animals suitable for further testing. Second, mice are exposed to various dilutions of scents to ascertain whether there is a threshold difference. Third, mice are presented with various scents, both attractive and aversive, that allow for the assessment of olfactory preference. These simple studies should make the initial characterization of olfactory behavior accessible for labs of varied resources and expertise. PMID:19229182

  12. Olfactory behavioral testing in the adult mouse.

    PubMed

    Witt, Rochelle M; Galligan, Meghan M; Despinoy, Jennifer R; Segal, Rosalind

    2009-01-28

    The rodent olfactory system is of increasing interest to scientists, studied, in part, in systems biology because of its stereotyped, yet accessible circuitry. In addition, this area's unique ability to generate new neurons throughout an organism's lifetime makes it an attractive system for developmental and regenerative biologists alike. Such interest necessitates a means for a quick, yet reliable assessment of olfactory function. Many tests of olfactory ability are complex, variable or not specifically designed for mice. Also, some tests are sensitive to memory deficits as well as defects in olfactory abilities, confounding obtained results. Here, we describe a simple battery of tests designed to identify defects in olfactory sensitivity and preference. First, an initial general health assessment allows for the identification of animals suitable for further testing. Second, mice are exposed to various dilutions of scents to ascertain whether there is a threshold difference. Third, mice are presented with various scents, both attractive and aversive, that allow for the assessment of olfactory preference. These simple studies should make the initial characterization of olfactory behavior accessible for labs of varied resources and expertise.

  13. Degeneration patterns of the olfactory receptor genes in sea snakes.

    PubMed

    Kishida, T; Hikida, T

    2010-02-01

    The sense of smell relies on the diversity of olfactory receptor (OR) repertoires in vertebrates. It has been hypothesized that different types of ORs are required in terrestrial and marine environments. Here we show that viviparous sea snakes, which do not rely on a terrestrial environment, have significantly lost ORs compared with their terrestrial relatives, supporting the hypothesis. On the other hand, oviparous sea snakes, which rely on a terrestrial environment for laying eggs, still maintain their ORs, reflecting the importance of the terrestrial environment for them. Furthermore, we found one Colubroidea snake (including sea snakes and their terrestrial relatives)-specific OR subfamily which had diverged widely during snake evolution after the blind snake-Colubroidea snake split. Interestingly, no pseudogenes are included in this subfamily in sea snakes, and this subfamily seems to have been expanding rapidly even in an underwater environment. These findings suggest that the Colubroidea-specific ORs detect nonvolatile odorants.

  14. Olfactory deposition of inhaled nanoparticles in humans

    PubMed Central

    Garcia, Guilherme J. M.; Schroeter, Jeffry D.; Kimbell, Julia S.

    2016-01-01

    Context Inhaled nanoparticles can migrate to the brain via the olfactory bulb, as demonstrated in experiments in several animal species. This route of exposure may be the mechanism behind the correlation between air pollution and human neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Objectives This manuscript aims to (1) estimate the dose of inhaled nanoparticles that deposit in the human olfactory epithelium during nasal breathing at rest and (2) compare the olfactory dose in humans with our earlier dose estimates for rats. Materials and methods An anatomically-accurate model of the human nasal cavity was developed based on computed tomography scans. The deposition of 1–100 nm particles in the whole nasal cavity and its olfactory region were estimated via computational fluid dynamics (CFD) simulations. Our CFD methods were validated by comparing our numerical predictions for whole-nose deposition with experimental data and previous CFD studies in the literature. Results In humans, olfactory dose of inhaled nanoparticles is highest for 1–2 nm particles with approximately 1% of inhaled particles depositing in the olfactory region. As particle size grows to 100 nm, olfactory deposition decreases to 0.01% of inhaled particles. Discussion and conclusion Our results suggest that the percentage of inhaled particles that deposit in the olfactory region is lower in humans than in rats. However, olfactory dose per unit surface area is estimated to be higher in humans due to their larger minute volume. These dose estimates are important for risk assessment and dose-response studies investigating the neurotoxicity of inhaled nanoparticles. PMID:26194036

  15. Olfactory deposition of inhaled nanoparticles in humans.

    PubMed

    Garcia, Guilherme J M; Schroeter, Jeffry D; Kimbell, Julia S

    2015-01-01

    Inhaled nanoparticles can migrate to the brain via the olfactory bulb, as demonstrated in experiments in several animal species. This route of exposure may be the mechanism behind the correlation between air pollution and human neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. This article aims to (i) estimate the dose of inhaled nanoparticles that deposit in the human olfactory epithelium during nasal breathing at rest and (ii) compare the olfactory dose in humans with our earlier dose estimates for rats. An anatomically-accurate model of the human nasal cavity was developed based on computed tomography scans. The deposition of 1-100 nm particles in the whole nasal cavity and its olfactory region were estimated via computational fluid dynamics (CFD) simulations. Our CFD methods were validated by comparing our numerical predictions for whole-nose deposition with experimental data and previous CFD studies in the literature. In humans, olfactory dose of inhaled nanoparticles is highest for 1-2 nm particles with ∼1% of inhaled particles depositing in the olfactory region. As particle size grows to 100 nm, olfactory deposition decreases to 0.01% of inhaled particles. Our results suggest that the percentage of inhaled particles that deposit in the olfactory region is lower in humans than in rats. However, olfactory dose per unit surface area is estimated to be higher in humans in the 1--7 nm size range due to the larger inhalation rate in humans. These dose estimates are important for risk assessment and dose-response studies investigating the neurotoxicity of inhaled nanoparticles.

  16. Stomatin-related olfactory protein, SRO, specifically expressed in the murine olfactory sensory neurons.

    PubMed

    Kobayakawa, Ko; Hayashi, Reiko; Morita, Kenji; Miyamichi, Kazunari; Oka, Yuichiro; Tsuboi, Akio; Sakano, Hitoshi

    2002-07-15

    We identified a stomatin-related olfactory protein (SRO) that is specifically expressed in olfactory sensory neurons (OSNs). The mouse sro gene encodes a polypeptide of 287 amino acids with a calculated molecular weight of 32 kDa. SRO shares 82% sequence similarity with the murine stomatin, 78% with Caenorhabditis elegans MEC-2, and 77% with C. elegans UNC-1. Unlike other stomatin-family genes, the sro transcript was present only in OSNs of the main olfactory epithelium. No sro expression was seen in vomeronasal neurons. SRO was abundant in most apical dendrites of OSNs, including olfactory cilia. Immunoprecipitation revealed that SRO associates with adenylyl cyclase type III and caveolin-1 in the low-density membrane fraction of olfactory cilia. Furthermore, anti-SRO antibodies stimulated cAMP production in fractionated cilia membrane. SRO may play a crucial role in modulating odorant signals in the lipid rafts of olfactory cilia.

  17. The Olfactory Mosaic: Bringing an Olfactory Network Together for Odor Perception.

    PubMed

    Courtiol, Emmanuelle; Wilson, Donald A

    2017-01-01

    Olfactory perception and its underlying neural mechanisms are not fixed, but rather vary over time, dependent on various parameters such as state, task, or learning experience. In olfaction, one of the primary sensory areas beyond the olfactory bulb is the piriform cortex. Due to an increasing number of functions attributed to the piriform cortex, it has been argued to be an associative cortex rather than a simple primary sensory cortex. In fact, the piriform cortex plays a key role in creating olfactory percepts, helping to form configural odor objects from the molecular features extracted in the nose. Moreover, its dynamic interactions with other olfactory and nonolfactory areas are also critical in shaping the olfactory percept and resulting behavioral responses. In this brief review, we will describe the key role of the piriform cortex in the larger olfactory perceptual network, some of the many actors of this network, and the importance of the dynamic interactions among the piriform-trans-thalamic and limbic pathways.

  18. Olfactory sensitivity to the pheromone, androstenone, is sexually dimorphic in the pig.

    PubMed

    Dorries, K M; Adkins-Regan, E; Halpern, B P

    1995-02-01

    Sexually dimorphic pheromone pathways have been used successfully to study insect olfactory coding. As one of the few mammalian species with an identified sex pheromone, the domestic pig (Sus scrofa) may be an ideal vertebrate species in which to examine sex differences in olfactory processing of a specific stimulus. In this experiment, androstenone and control odor detection thresholds were measured in adult male, female, and castrated male pigs. In an operant task, pigs were tested with descending concentration series of both androstenone and geraniol. All groups were equally sensitive to geraniol, but there was a sex difference in sensitivity to the odor of androstenone. Female pigs' detection threshold was a dilution fivefold lower than the threshold for intact males. Castrated males did not differ significantly from either males or females. This is the first example of a sexual dimorphism in sensitivity to a mammalian pheromone.

  19. Evidence for inhibition of cholinesterases in insect and mammalian nervous systems by the insect repellent deet

    PubMed Central

    Corbel, Vincent; Stankiewicz, Maria; Pennetier, Cédric; Fournier, Didier; Stojan, Jure; Girard, Emmanuelle; Dimitrov, Mitko; Molgó, Jordi; Hougard, Jean-Marc; Lapied, Bruno

    2009-01-01

    Background N,N-Diethyl-3-methylbenzamide (deet) remains the gold standard for insect repellents. About 200 million people use it every year and over 8 billion doses have been applied over the past 50 years. Despite the widespread and increased interest in the use of deet in public health programmes, controversies remain concerning both the identification of its target sites at the olfactory system and its mechanism of toxicity in insects, mammals and humans. Here, we investigated the molecular target site for deet and the consequences of its interactions with carbamate insecticides on the cholinergic system. Results By using toxicological, biochemical and electrophysiological techniques, we show that deet is not simply a behaviour-modifying chemical but that it also inhibits cholinesterase activity, in both insect and mammalian neuronal preparations. Deet is commonly used in combination with insecticides and we show that deet has the capacity to strengthen the toxicity of carbamates, a class of insecticides known to block acetylcholinesterase. Conclusion These findings question the safety of deet, particularly in combination with other chemicals, and they highlight the importance of a multidisciplinary approach to the development of safer insect repellents for use in public health. PMID:19656357

  20. Exploring Sound with Insects

    ERIC Educational Resources Information Center

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  1. Sunflower insect pests

    USDA-ARS?s Scientific Manuscript database

    Like other annual crops, sunflowers are fed upon by a variety of insect pests capable of reducing yields. Though there are a few insects which are considered consistent or severe (e.g., sunflower moth, banded sunflower moth, red sunflower seed weevil), many more insects are capable of causing proble...

  2. Insects and Spiders.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

    This set of teaching aids consists of nine Audubon Nature Bulletins, providing teachers and students with informational reading on insects and spiders. The bulletins have these titles: What Good Are Insects, How Insects Benefit Man, Life of the Honey Bee, Ants and Their Fascinating Ways, Mosquitoes and Other Flies, Caterpillars, Spiders and Silk,…

  3. Insect phermones: diet related?

    PubMed

    Hendry, L B

    1976-04-09

    The question of the origin of insect pheromones is discussed in the light of new published information on the communication system of the oak leaf roller. It is concluded that compounds found in diets may be partially responsible for insect sexual behavior and that substructuring of insect populations in ecological and evolutionary time through dietary chemicals remains a hypothesis worthy of further testing.

  4. Exploring Sound with Insects

    ERIC Educational Resources Information Center

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  5. Acoustic Monitoring of Insects

    USDA-ARS?s Scientific Manuscript database

    Farmers, grain elevator managers, and food processors often sample grain for insect damaged kernels and numbers of live adult insects but these easily obtained measurements of insect levels do not provide reliable estimates of the typically much larger populations of internally feeding immature inse...

  6. Insects and Spiders.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

    This set of teaching aids consists of nine Audubon Nature Bulletins, providing teachers and students with informational reading on insects and spiders. The bulletins have these titles: What Good Are Insects, How Insects Benefit Man, Life of the Honey Bee, Ants and Their Fascinating Ways, Mosquitoes and Other Flies, Caterpillars, Spiders and Silk,…

  7. Insects and Others.

    ERIC Educational Resources Information Center

    Mills, Richard

    1984-01-01

    Several ideas for observing insects and soil animals in the classroom are provided. Also provided are: (1) procedures for making insect cages with milk cartons; (2) suggestions for collecting and feeding insects; and (3) techniques for collecting and identifying soil animals. (BC)

  8. Unraveling Cajal's view of the olfactory system

    PubMed Central

    Figueres-Oñate, María; Gutiérrez, Yolanda; López-Mascaraque, Laura

    2014-01-01

    The olfactory system has a highly regular organization of interconnected synaptic circuits from the periphery. It is therefore an excellent model for understanding general principles about how the brain processes information. Cajal revealed the basic cell types and their interconnections at the end of the XIX century. Since his original descriptions, the observation and analysis of the olfactory system and its components represents a major topic in neuroscience studies, providing important insights into the neural mechanisms. In this review, we will highlight the importance of Cajal contributions and his legacy to the actual knowledge of the olfactory system. PMID:25071462

  9. InsectBase: a resource for insect genomes and transcriptomes.

    PubMed

    Yin, Chuanlin; Shen, Gengyu; Guo, Dianhao; Wang, Shuping; Ma, Xingzhou; Xiao, Huamei; Liu, Jinding; Zhang, Zan; Liu, Ying; Zhang, Yiqun; Yu, Kaixiang; Huang, Shuiqing; Li, Fei

    2016-01-04

    The genomes and transcriptomes of hundreds of insects have been sequenced. However, insect community lacks an integrated, up-to-date collection of insect gene data. Here, we introduce the first release of InsectBase, available online at http://www.insect-genome.com. The database encompasses 138 insect genomes, 116 insect transcriptomes, 61 insect gene sets, 36 gene families of 60 insects, 7544 miRNAs of 69 insects, 96,925 piRNAs of Drosophila melanogaster and Chilo suppressalis, 2439 lncRNA of Nilaparvata lugens, 22,536 pathways of 78 insects, 678,881 untranslated regions (UTR) of 84 insects and 160,905 coding sequences (CDS) of 70 insects. This release contains over 12 million sequences and provides search functionality, a BLAST server, GBrowse, insect pathway construction, a Facebook-like network for the insect community (iFacebook), and phylogenetic analysis of selected genes.

  10. InsectBase: a resource for insect genomes and transcriptomes

    PubMed Central

    Yin, Chuanlin; Shen, Gengyu; Guo, Dianhao; Wang, Shuping; Ma, Xingzhou; Xiao, Huamei; Liu, Jinding; Zhang, Zan; Liu, Ying; Zhang, Yiqun; Yu, Kaixiang; Huang, Shuiqing; Li, Fei

    2016-01-01

    The genomes and transcriptomes of hundreds of insects have been sequenced. However, insect community lacks an integrated, up-to-date collection of insect gene data. Here, we introduce the first release of InsectBase, available online at http://www.insect-genome.com. The database encompasses 138 insect genomes, 116 insect transcriptomes, 61 insect gene sets, 36 gene families of 60 insects, 7544 miRNAs of 69 insects, 96 925 piRNAs of Drosophila melanogaster and Chilo suppressalis, 2439 lncRNA of Nilaparvata lugens, 22 536 pathways of 78 insects, 678 881 untranslated regions (UTR) of 84 insects and 160 905 coding sequences (CDS) of 70 insects. This release contains over 12 million sequences and provides search functionality, a BLAST server, GBrowse, insect pathway construction, a Facebook-like network for the insect community (iFacebook), and phylogenetic analysis of selected genes. PMID:26578584

  11. Exotic models may offer unique opportunities to decipher specific scientific question: the case of Xenopus olfactory system.

    PubMed

    Gascuel, Jean; Amano, Tosikazu

    2013-09-01

    The fact that olfactory systems are highly conserved in all animal species from insects to mammals allow the generalization of findings from one species to another. Most of our knowledge about the anatomy and physiology of the olfactory system comes from data obtained in a very limited number of biological models such as rodents, Zebrafish, Drosophila, and a worm, Caenorhabditis elegans. These models have proved useful to answer most questions in the field of olfaction, and thus concentrating on these few models appear to be a pragmatic strategy. However, the diversity of the organization and physiology of the olfactory system amongst phyla appear to be greater than generally assumed and the four models alone may not be sufficient to address all the questions arising from the study of olfaction. In this article, we will illustrate the idea that we should take advantage of biological diversity to address specific scientific questions and will show that the Xenopus olfactory system is a very good model to investigate: first, olfaction in aerial versus aquatic conditions and second, mechanisms underlying postnatal reorganization of the olfactory system especially those controlled by tyroxine hormone. Copyright © 2013 Wiley Periodicals, Inc.

  12. Identification of Putative Olfactory Genes from the Oriental Fruit Moth Grapholita molesta via an Antennal Transcriptome Analysis

    PubMed Central

    Li, Yiping; Wu, Junxiang

    2015-01-01

    Background The oriental fruit moth, Grapholita molesta, is an extremely important oligophagous pest species of stone and pome fruits throughout the world. As a host-switching species, adult moths, especially females, depend on olfactory cues to a large extent in locating host plants, finding mates, and selecting oviposition sites. The identification of olfactory genes can facilitate investigation on mechanisms for chemical communications. Methodology/Principal Finding We generated transcriptome of female antennae of G.molesta using the next-generation sequencing technique, and assembled transcripts from RNA-seq reads using Trinity, SOAPdenovo-trans and Abyss-trans assemblers. We identified 124 putative olfactory genes. Among the identified olfactory genes, 118 were novel to this species, including 28 transcripts encoding for odorant binding proteins, 17 chemosensory proteins, 48 odorant receptors, four gustatory receptors, 24 ionotropic receptors, two sensory neuron membrane proteins, and one odor degrading enzyme. The identified genes were further confirmed through semi-quantitative reverse transcription PCR for transcripts coding for 26 OBPs and 17 CSPs. OBP transcripts showed an obvious antenna bias, whereas CSP transcripts were detected in different tissues. Conclusion Antennal transcriptome data derived from the oriental fruit moth constituted an abundant molecular resource for the identification of genes potentially involved in the olfaction process of the species. This study provides a foundation for future research on the molecules involved in olfactory recognition of this insect pest, and in particular, the feasibility of using semiochemicals to control this pest. PMID:26540284

  13. Rapid and slow chemical synaptic interactions of cholinergic projection neurons and GABAergic local interneurons in the insect antennal lobe.

    PubMed

    Warren, Ben; Kloppenburg, Peter

    2014-09-24

    The antennal lobe (AL) of insects constitutes the first synaptic relay and processing center of olfactory information, received from olfactory sensory neurons located on the antennae. Complex synaptic connectivity between olfactory neurons of the AL ultimately determines the spatial and temporal tuning profile of (output) projection neurons to odors. Here we used paired whole-cell patch-clamp recordings in the cockroach Periplaneta americana to characterize synaptic interactions between cholinergic uniglomerular projection neurons (uPNs) and GABAergic local interneurons (LNs), both of which are key components of the insect olfactory system. We found rapid, strong excitatory synaptic connections between uPNs and LNs. This rapid excitatory transmission was blocked by the nicotinic acetylcholine receptor blocker mecamylamine. IPSPs, elicited by synaptic input from a presynaptic LN, were recorded in both uPNs and LNs. IPSPs were composed of both slow, sustained components and fast, transient components which were coincident with presynaptic action potentials. The fast IPSPs were blocked by the GABAA receptor chloride channel blocker picrotoxin, whereas the slow sustained IPSPs were blocked by the GABAB receptor blocker CGP-54626. This is the first study to directly show the predicted dual fast- and slow-inhibitory action of LNs, which was predicted to be key in shaping complex odor responses in the AL of insects. We also provide the first direct characterization of rapid postsynaptic potentials coincident with presynaptic spikes between olfactory processing neurons in the AL.

  14. Expression of ionotropic receptors in terrestrial hermit crab's olfactory sensory neurons.

    PubMed

    Groh-Lunow, Katrin C; Getahun, Merid N; Grosse-Wilde, Ewald; Hansson, Bill S

    2014-01-01

    Coenobitidae are one out of at least five crustacean lineages which independently succeeded in the transition from water to land. This change in lifestyle required adaptation of the peripheral olfactory organs, the antennules, in order to sense chemical cues in the new terrestrial habitat. Hermit crab olfactory aesthetascs are arranged in a field on the distal segment of the antennular flagellum. Aesthetascs house approximately 300 dendrites with their cell bodies arranged in spindle-like complexes of ca. 150 cell bodies each. While the aesthetascs of aquatic crustaceans have been shown to be the place of odor uptake and previous studies identified ionotropic receptors (IRs) as the putative chemosensory receptors expressed in decapod antennules, the expression of IRs besides the IR co-receptors IR25a and IR93a in olfactory sensory neurons (OSNs) has not been documented yet. Our goal was to reveal the expression and distribution pattern of non-co-receptor IRs in OSNs of Coenobita clypeatus, a terrestrial hermit crab, with RNA in situ hybridization. We expanded our previously published RNAseq dataset, and revealed 22 novel IR candidates in the Coenobita antennules. We then used RNA probes directed against three different IRs to visualize their expression within the OSN cell body complexes. Furthermore we aimed to characterize ligand spectra of single aesthetascs by recording local field potentials and responses from individual dendrites. This also allowed comparison to functional data from insect OSNs expressing antennal IRs. We show that this orphan receptor subgroup with presumably non-olfactory function in insects is likely the basis of olfaction in terrestrial hermit crabs.

  15. Expression of ionotropic receptors in terrestrial hermit crab's olfactory sensory neurons

    PubMed Central

    Groh-Lunow, Katrin C.; Getahun, Merid N.; Grosse-Wilde, Ewald; Hansson, Bill S.

    2015-01-01

    Coenobitidae are one out of at least five crustacean lineages which independently succeeded in the transition from water to land. This change in lifestyle required adaptation of the peripheral olfactory organs, the antennules, in order to sense chemical cues in the new terrestrial habitat. Hermit crab olfactory aesthetascs are arranged in a field on the distal segment of the antennular flagellum. Aesthetascs house approximately 300 dendrites with their cell bodies arranged in spindle-like complexes of ca. 150 cell bodies each. While the aesthetascs of aquatic crustaceans have been shown to be the place of odor uptake and previous studies identified ionotropic receptors (IRs) as the putative chemosensory receptors expressed in decapod antennules, the expression of IRs besides the IR co-receptors IR25a and IR93a in olfactory sensory neurons (OSNs) has not been documented yet. Our goal was to reveal the expression and distribution pattern of non-co-receptor IRs in OSNs of Coenobita clypeatus, a terrestrial hermit crab, with RNA in situ hybridization. We expanded our previously published RNAseq dataset, and revealed 22 novel IR candidates in the Coenobita antennules. We then used RNA probes directed against three different IRs to visualize their expression within the OSN cell body complexes. Furthermore we aimed to characterize ligand spectra of single aesthetascs by recording local field potentials and responses from individual dendrites. This also allowed comparison to functional data from insect OSNs expressing antennal IRs. We show that this orphan receptor subgroup with presumably non-olfactory function in insects is likely the basis of olfaction in terrestrial hermit crabs. PMID:25698921

  16. Repeated formaldehyde inhalation impaired olfactory function and changed SNAP25 proteins in olfactory bulb.

    PubMed

    Zhang, Qi; Yan, Weiqun; Bai, Yang; Zhu, Yingqiao; Ma, Jie

    2014-10-01

    Formaldehyde inhalation exposure, which can occur through occupational exposure, can lead to sensory irritation, neurotoxicity, mood disorders, and learning and memory impairment. However, its influence on olfactory function is unclear. To investigate the mechanism and the effect of repeated formaldehyde inhalation exposure on olfactory function. Rats were treated with formaldehyde inhalation (13·5±1·5 ppm, twice 30 minutes/day) for 14 days. Buried food pellet and locomotive activity tests were used to detect olfactory function and locomotion. Western blots were used to evaluate synaptosomal-associated protein 25 (SNAP25) protein levels in the olfactory bulb (OB) lysate and synaptosome, as well as mature and immature olfactory sensory neuron markers, olfactory marker protein (OMP), and Tuj-1. Real-time polymerase chain reaction (PCR) was used to detect SNAP25 mRNA amounts. Repeated formaldehyde inhalation exposure impaired olfactory function, whereas locomotive activities were unaffected. SNAP25 protein decreased significantly in the OB, but not in the occipital lobe. SNAP25 also decreased in the OB synaptosome when synaptophysin did not change after formaldehyde treatment. mRNA levels of SNAP25A and SNAP25B were unaffected. Mature and immature olfactory sensory neuron marker, OMP, and Tuj-1, did not change after formaldehyde treatment. Repeated formaldehyde exposure impaired olfactory function by disturbing SNAP25 protein in the OB.

  17. A deceptive pollination system targeting drosophilids through olfactory mimicry of yeast.

    PubMed

    Stökl, Johannes; Strutz, Antonia; Dafni, Amots; Svatos, Ales; Doubsky, Jan; Knaden, Markus; Sachse, Silke; Hansson, Bill S; Stensmyr, Marcus C

    2010-10-26

    In deceptive pollination, insects are bamboozled into performing nonrewarded pollination. A prerequisite for the evolutionary stability in such systems is that the plants manage to generate a perfect sensory impression of a desirable object in the insect nervous system [1]. The study of these plants can provide important insights into sensory preference of their visiting insects. Here, we present the first description of a deceptive pollination system that specifically targets drosophilid flies. We show that the examined plant (Arum palaestinum) accomplishes its deception through olfactory mimicry of fermentation, a strategy that represents a novel pollination syndrome. The lily odor is composed of volatiles characteristic of yeast, and produces in Drosophila melanogaster an antennal detection pattern similar to that elicited by a range of fermentation products. By functional imaging, we show that the lily odors target a specific subset of odorant receptors (ORs), which include the most conserved OR genes in the drosophilid olfactome. Furthermore, seven of eight visiting drosophilid species show a congruent olfactory response pattern to the lily, in spite of comprising species pairs separated by ∼40 million years [2], showing that the lily targets a basal function of the fly nose, shared by species with similar ecological preference.

  18. Parallel Olfactory Processing in the Honey Bee Brain: Odor Learning and Generalization under Selective Lesion of a Projection Neuron Tract.

    PubMed

    Carcaud, Julie; Giurfa, Martin; Sandoz, Jean Christophe

    2015-01-01

    The function of parallel neural processing is a fundamental problem in Neuroscience, as it is found across sensory modalities and evolutionary lineages, from insects to humans. Recently, parallel processing has attracted increased attention in the olfactory domain, with the demonstration in both insects and mammals that different populations of second-order neurons encode and/or process odorant information differently. Among insects, Hymenoptera present a striking olfactory system with a clear neural dichotomy from the periphery to higher-order centers, based on two main tracts of second-order (projection) neurons: the medial and lateral antennal lobe tracts (m-ALT and l-ALT). To unravel the functional role of these two pathways, we combined specific lesions of the m-ALT tract with behavioral experiments, using the classical conditioning of the proboscis extension response (PER conditioning). Lesioned and intact bees had to learn to associate an odorant (1-nonanol) with sucrose. Then the bees were subjected to a generalization procedure with a range of odorants differing in terms of their carbon chain length or functional group. We show that m-ALT lesion strongly affects acquisition of an odor-sucrose association. However, lesioned bees that still learned the association showed a normal gradient of decreasing generalization responses to increasingly dissimilar odorants. Generalization responses could be predicted to some extent by in vivo calcium imaging recordings of l-ALT neurons. The m-ALT pathway therefore seems necessary for normal classical olfactory conditioning performance.

  19. Parallel Olfactory Processing in the Honey Bee Brain: Odor Learning and Generalization under Selective Lesion of a Projection Neuron Tract

    PubMed Central

    Carcaud, Julie; Giurfa, Martin; Sandoz, Jean Christophe

    2016-01-01

    The function of parallel neural processing is a fundamental problem in Neuroscience, as it is found across sensory modalities and evolutionary lineages, from insects to humans. Recently, parallel processing has attracted increased attention in the olfactory domain, with the demonstration in both insects and mammals that different populations of second-order neurons encode and/or process odorant information differently. Among insects, Hymenoptera present a striking olfactory system with a clear neural dichotomy from the periphery to higher-order centers, based on two main tracts of second-order (projection) neurons: the medial and lateral antennal lobe tracts (m-ALT and l-ALT). To unravel the functional role of these two pathways, we combined specific lesions of the m-ALT tract with behavioral experiments, using the classical conditioning of the proboscis extension response (PER conditioning). Lesioned and intact bees had to learn to associate an odorant (1-nonanol) with sucrose. Then the bees were subjected to a generalization procedure with a range of odorants differing in terms of their carbon chain length or functional group. We show that m-ALT lesion strongly affects acquisition of an odor-sucrose association. However, lesioned bees that still learned the association showed a normal gradient of decreasing generalization responses to increasingly dissimilar odorants. Generalization responses could be predicted to some extent by in vivo calcium imaging recordings of l-ALT neurons. The m-ALT pathway therefore seems necessary for normal classical olfactory conditioning performance. PMID:26834589

  20. Expression and modulation of neuroligin and neurexin in the olfactory organ of the cotton leaf worm Spodoptera littoralis.

    PubMed

    Durand, Nicolas; Chertemps, Thomas; Bozzolan, Françoise; Maïbèche, Martine

    2017-04-01

    Carboxylesterases are enzymes widely distributed within living organisms. In insects, they have been mainly involved in dietary metabolism and detoxification function. Interestingly, several members of this family called carboxylesterase-like adhesion molecules (CLAMs) have lost their catalytic properties and are mainly involved in neuro/developmental functions. CLAMs include gliotactins, neurotactins, glutactins, and neuroligins. The latter have for binding partner the neurexin. In insects, the function of these proteins has been mainly studied in Drosophila central nervous system or neuromuscular junction. Some studies suggested a role of neuroligins and neurexin in sensory processing but CLAM expression within sensory systems has not been investigated. Here, we reported the identification of 5 putative CLAMs expressed in the olfactory system of the model pest insect Spodoptera littoralis. One neuroligin, Slnlg4-yll and its putative binding partner neurexin SlnrxI were the most expressed in the antennae and were surprisingly associated with olfactory sensilla. In addition, both transcripts were upregulated in male antennae after mating, known to modulate the sensitivity of the peripheral olfactory system in S. littoralis, suggesting that these molecules could be involved in sensory plasticity.

  1. Pharmacology of mammalian olfactory receptors.

    PubMed

    Smith, Richard S; Peterlin, Zita; Araneda, Ricardo C

    2013-01-01

    Mammalian species have evolved a large and diverse number of odorant receptors (ORs). These proteins comprise the largest family of G-protein-coupled receptors (GPCRs) known, amounting to ~1,000-different receptors in the rodent. From the perspective of olfactory coding, the availability of such a vast number of chemosensory receptors poses several fascinating questions; in addition, such a large repertoire provides an attractive biological model to study ligand-receptor interactions. The limited functional expression of these receptors in heterologous systems, however, has greatly hampered attempts to deorphanize them. We have employed a successful approach that combines electrophysiological and imaging techniques to analyze the response profiles of single sensory neurons. Our approach has enabled us to characterize the "odor space" of a population of native aldehyde receptors and the molecular range of a genetically engineered receptor, OR-I7.

  2. Correlation between olfactory severity ratings based on olfactory function test scores and self-reported severity rating of olfactory loss.

    PubMed

    Seok, Jungirl; Shim, Ye Ji; Rhee, Chae-Seo; Kim, Jeong-Whun

    2017-07-01

    Olfactory test scores are significantly correlated with self-rated severity scales. However, the statistical rating based on olfactory tests did not strongly agree with the self-reported severity rating. This suggests that there is a discrepancy between olfactory test results and the severity described by patients themselves. This study aimed to identify the correlation between statistical ratings based on test scores and self-rating of the severity of olfactory loss. A total of 1555 subjects were asked to rate olfactory loss severity by one of five scales. Olfactory tests consist of the butanol threshold test (BTT) and cross-cultural smell identification test (CCSIT). There were significant correlations between BTT scores and self-rated severity scales (r = 0.619, p < 0.001) and between CCSIT scores and self-rated severity scales (r = 0.597, p < 0.001) after adjustment for age, sex, and medical conditions. Using discriminant analysis for both BTT and CCSIT, scores 0-4 could be statistically rated as anosmia, scores 5 and 6 as severe hyposmia, scores 7 and 8 as moderate hyposmia, and scores 9-12 as normosmia (Wilks's lambda = 0.605, p < 0.001 for BTT and Wilks's lambda = 0.597, p < 0.001 for CCSIT).

  3. A Novel Application for Cognitive Evaluation in Mountain Ultramarathons: Olfactory Assessment.

    PubMed

    Tonacci, Alessandro; Billeci, Lucia; Tartarisco, Gennaro; Mastorci, Francesca; Borghini, Andrea; Mrakic-Sposta, Simona; Moretti, Sarah; Vezzoli, Alessandra; Faraguna, Ugo; Pioggia, Giovanni; Guido, Giardini; Pratali, Lorenza

    2016-03-01

    Olfactory function, a cognitive impairment biomarker, was evaluated in mountain ultramarathon (MUM) runners during the Tor des Géants race (332.5 km with an overall altitude gain of 24,000 m; altitude range 330-3296 m above the sea). An Odor Identification Test was administered before (T0; n = 53), at 148.7 kms (T1; n = 32) and after the race (T2; n = 28). The effect of dehydration and sleep deprivation on olfactory function was assessed. Olfactory function was also assessed in non-MUM athletes and sedentary controls (C) at rest. A majority of the athletes completed the olfactory test at all time intervals. Olfactory function decreased throughout the race (T0: 13.8 ± 1.9, T1: 13.7 ± 1.6, T2: 13.1 ± 1.8; T0 vs T2 P = .01). There was no relationship with race time or sleep deprivation on the sense of smell throughout the competition. However, there was a combined effect with decreased olfaction during the second half of the race, while a poor relationship was seen between olfaction and total body water at midterm (T1: rs = -0.427; P = .019), but not at baseline or after the race. MUM athletes had similar olfactory scores to C (13.8 ± 1.9 vs 13.7 ± 1.4) and non-MUM (13.8 ± 1.9 vs 13.9 ± 1.6) athletes. This pilot study showed the feasibility of olfactory evaluation as a minimally invasive cognitive impairment assessment. The test can be used in logistically difficult environments, adding scientific value to this promising method. Although olfaction decreased after prolonged physical activity, further studies are warranted to make the relationship between cognition and external factors (eg, sleep deprivation, dehydration) more clear. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  4. Insect barcode information system.

    PubMed

    Pratheepa, Maria; Jalali, Sushil Kumar; Arokiaraj, Robinson Silvester; Venkatesan, Thiruvengadam; Nagesh, Mandadi; Panda, Madhusmita; Pattar, Sharath

    2014-01-01

    Insect Barcode Information System called as Insect Barcode Informática (IBIn) is an online database resource developed by the National Bureau of Agriculturally Important Insects, Bangalore. This database provides acquisition, storage, analysis and publication of DNA barcode records of agriculturally important insects, for researchers specifically in India and other countries. It bridges a gap in bioinformatics by integrating molecular, morphological and distribution details of agriculturally important insects. IBIn was developed using PHP/My SQL by using relational database management concept. This database is based on the client- server architecture, where many clients can access data simultaneously. IBIn is freely available on-line and is user-friendly. IBIn allows the registered users to input new information, search and view information related to DNA barcode of agriculturally important insects.This paper provides a current status of insect barcode in India and brief introduction about the database IBIn. http://www.nabg-nbaii.res.in/barcode.

  5. Olfactory assessment using the NIH Toolbox

    PubMed Central

    Doty, Richard L.; Murphy, Claire; Frank, Robert; Hoffman, Howard J.; Maute, Christopher; Kallen, Michael A.; Slotkin, Jerry

    2013-01-01

    The human olfactory system provides us with information about our environment that is critical to our physical and psychological well-being. Individuals can vary widely in their ability to detect, recognize, and identify odors, but still be within the range of normal function. Although several standardized tests of odor identification are available, few specifically address the issues in testing very young children, most of whom are likely to be unfamiliar with many of the odor stimuli used in adult tests and have limited ability to read and identify labels to select among choices. Based on the format of the San Diego Odor Identification Test and the delivery system of the University of Pennsylvania Smell Identification Test, we developed 2 versions of an odor identification test using standardized odor stimuli in a scratch-and-sniff format in which participants match 5 (children) or 9 (adults) odors to pictures representing the odor source. Results from normative testing and validation showed that for most participants, the test could be completed in 5 minutes or less and that the poorer performance among the youngest children and the elderly was consistent with data from tests with larger numbers of items. Expanding on the pediatric version of the test with adult-specific and public health–relevant odors increased the ecological validity of the test and facilitated comparisons of intraindividual performance across developmental stages. PMID:23479541

  6. Modeling Olfactory Bulb Evolution through Primate Phylogeny

    PubMed Central

    Heritage, Steven

    2014-01-01

    Adaptive characterizations of primates have usually included a reduction in olfactory sensitivity. However, this inference of derivation and directionality assumes an ancestral state of olfaction, usually by comparison to a group of extant non-primate mammals. Thus, the accuracy of the inference depends on the assumed ancestral state. Here I present a phylogenetic model of continuous trait evolution that reconstructs olfactory bulb volumes for ancestral nodes of primates and mammal outgroups. Parent-daughter comparisons suggest that, relative to the ancestral euarchontan, the crown-primate node is plesiomorphic and that derived reduction in olfactory sensitivity is an attribute of the haplorhine lineage. The model also suggests a derived increase in olfactory sensitivity at the strepsirrhine node. This oppositional diversification of the strepsirrhine and haplorhine lineages from an intermediate and non-derived ancestor is inconsistent with a characterization of graded reduction through primate evolution. PMID:25426851

  7. The Pig Olfactory Brain: A Primer

    PubMed Central

    Feldman, Sanford; Osterberg, Stephen K.

    2016-01-01

    Despite the fact that pigs are reputed to have excellent olfactory abilities, few studies have examined regions of the pig brain involved in the sense of smell. The present study provides an overview of the olfactory bulb, anterior olfactory nucleus, and piriform cortex of adult pigs using several approaches. Nissl, myelin, and Golgi stains were used to produce a general overview of the organization of the regions and confocal microscopy was employed to examine 1) projection neurons, 2) GABAergic local circuit neurons that express somatostatin, parvalbumin, vasoactive intestinal polypeptide, or calretinin, 3) neuromodulatory fibers (cholinergic and serotonergic), and 4) glia (astrocytes and microglia). The findings revealed that pig olfactory structures are quite large, highly organized and follow the general patterns observed in mammals. PMID:26936231

  8. Methods to measure olfactory behavior in mice

    PubMed Central

    Zou, Junhui; Wang, Wenbin; Pan, Yung-Wei; Lu, Song; Xia, Zhengui

    2015-01-01

    Mice rely on the sense of olfaction to detect food sources, recognize social and mating partners, and avoid predators. Many behaviors of mice including learning and memory, social interaction, fear, and anxiety are closely associated with their function of olfaction, and behavior tasks designed to evaluate those brain functions may use odors as cues. Accurate assessment of olfaction is not only essential for the study of olfactory system but also critical for proper interpretation of various mouse behaviors especially learning and memory, emotionality and affect, and sociality. Here we describe a series of behavior experiments that offer multidimensional and quantitative assessments for mouse’s olfactory function, including olfactory habituation, discrimination, odor preference, odor detection sensitivity, and olfactory memory, to both social and nonsocial odors. PMID:25645244

  9. A multisensory network for olfactory processing

    PubMed Central

    Maier, Joost X.; Blankenship, Meredith L.; Li, Jennifer X.; Katz, Donald B.

    2015-01-01

    Summary Primary gustatory cortex (GC) is connected (both mono- and poly-synaptically) to primary olfactory (piriform) cortex (PC)—connections that might be hypothesized to underlie the construction of a “flavor” percept when both gustatory and olfactory stimuli are present. Here, we use multi-site electrophysiology and optical inhibition of GC neurons (GCx, produced via infection with ArchT) to demonstrate that, indeed, during gustatory stimulation, taste-selective information is transmitted from GC to PC. We go on to show that these connections impact olfactory processing even in the absence of gustatory stimulation: GCx alters PC responses to olfactory stimuli presented alone, enhancing some and eliminating others, despite leaving the path from nasal epithelium to PC intact. Finally, we show the functional importance of this latter phenomenon, demonstrating that GCx renders rats unable to properly recognize odor stimuli. This sequence of findings suggests that sensory processing may be more intrinsically integrative than previously thought. PMID:26441351

  10. Long-term olfactory memories are stabilised via protein synthesis in Camponotus fellah ants.

    PubMed

    Guerrieri, Fernando J; d'Ettorre, Patrizia; Devaud, Jean-Marc; Giurfa, Martin

    2011-10-01

    Ants exhibit impressive olfactory learning abilities. Operant protocols in which ants freely choose between rewarded and non-rewarded odours have been used to characterise associative olfactory learning and memory. Yet, this approach precludes the use of invasive methods allowing the dissection of molecular bases of learning and memory. An open question is whether the memories formed upon olfactory learning that are retrievable several days after training are indeed based on de novo protein synthesis. Here, we addressed this question in the ant Camponotus fellah using a conditioning protocol in which individually harnessed ants learn an association between odour and reward. When the antennae of an ant are stimulated with sucrose solution, the insect extends its maxilla-labium to absorb the solution (maxilla-labium extension response). We differentially conditioned ants to discriminate between two long-chain hydrocarbons, one paired with sucrose and the other with quinine solution. Differential conditioning leads to the formation of a long-term memory retrievable at least 72 h after training. Long-term memory consolidation was impaired by the ingestion of cycloheximide, a protein synthesis blocker, prior to conditioning. Cycloheximide did not impair acquisition of either short-term memory (10 min) or early and late mid-term memories (1 or 12 h). These results show that, upon olfactory learning, ants form different memories with variable molecular bases. While short- and mid-term memories do not require protein synthesis, long-term memories are stabilised via protein synthesis. Our behavioural protocol opens interesting research avenues to explore the cellular and molecular bases of olfactory learning and memory in ants.

  11. Neurophysiological and behavioral responses of gypsy moth larvae to insect repellents: DEET, IR3535, and picaridin.

    PubMed

    Sanford, Jillian L; Barski, Sharon A; Seen, Christina M; Dickens, Joseph C; Shields, Vonnie D C

    2014-01-01

    The interactions between insect repellents and the olfactory system have been widely studied, however relatively little is known about the effects of repellents on the gustatory system of insects. In this study, we show that the gustatory receptor neuron (GRN) located in the medial styloconic sensilla on the maxillary palps of gypsy moth larvae, and known to be sensitive to feeding deterrents, also responds to the insect repellents DEET, IR3535, and picaridin. These repellents did not elicit responses in the lateral styloconic sensilla. Moreover, behavioral studies demonstrated that each repellent deterred feeding. This is the first study to show perception of insect repellents by the gustatory system of a lepidopteran larva and suggests that detection of a range of bitter or aversive compounds may be a broadly conserved feature among insects.

  12. Avoiding DEET through insect gustatory receptors.

    PubMed

    Lee, Youngseok; Kim, Sang Hoon; Montell, Craig

    2010-08-26

    DEET is the most widely used insect repellent worldwide. In Drosophila olfactory receptor neurons (ORNs), DEET is detected through a mechanism employing the olfactory receptor, OR83b. However, it is controversial as to whether ORNs respond directly to DEET or whether DEET blocks the response to attractive odors. Here, we showed that DEET suppressed feeding behavior in Drosophila, and this effect was mediated by gustatory receptor neurons (GRNs). DEET was potent in suppressing feeding as <0.1% DEET elicited aversive behavior. Inhibition of feeding required multiple gustatory receptors (GRs) expressed in inhibitory GRNs. DEET stimulated action potentials in GRNs that respond to aversive compounds, and this response was lost in the Gr32a, Gr33a, and Gr66a mutants. Since 0.02% DEET elicited action potentials, we conclude that DEET directly activates of GRNs. We suggest that the effectiveness of DEET in pest control owes to its dual action in inducing avoidance simultaneously via GRNs and ORNs. 2010 Elsevier Inc. All rights reserved.

  13. Olfactory learning and memory in the disease vector mosquito Aedes aegypti

    PubMed Central

    Vinauger, Clément; Lutz, Eleanor K.; Riffell, Jeffrey A.

    2014-01-01

    Olfactory learning in blood-feeding insects, such as mosquitoes, could play an important role in host preference and disease transmission. However, standardised protocols allowing testing of their learning abilities are currently lacking, and how different olfactory stimuli are learned by these insects remains unknown. Using a Pavlovian conditioning paradigm, we trained individuals and groups of Aedes aegypti mosquitoes to associate an odorant conditioned stimulus (CS) with a blood-reinforced thermal stimulus (unconditioned stimulus; US). Results showed, first, that mosquitoes could learn the association between L-lactic acid and the US, and retained the association for at least 24 h. Second, the success of olfactory conditioning was dependent upon the CS – some odorants that elicited indifferent responses in naïve mosquitoes, such as L-lactic acid and 1-octen-3-ol, were readily learned, whereas others went from aversive to attractive after training (Z-3-hexen-1-ol) or were untrainable (β-myrcene and benzyl alcohol). Third, we examined whether mosquitoes' ability to learn could interfere with the action of the insect repellent DEET. Results demonstrated that pre-exposure and the presence of DEET in the CS reduced the aversive effects of DEET. Last, the nature of the formed memories was explored. Experiments using cold-shock treatments within the first 6 h post-training (for testing anaesthesia-resistant memory) and a protein synthesis inhibitor (cycloheximide; to disrupt the formation of long-term memory) both affected mosquitoes' performances. Together, these results show that learning is a crucial component in odour responses in A. aegypti, and provide the first evidence for the functional role of different memory traces in these responses. PMID:24737761

  14. GABAB Receptors Tune Cortical Feedback to the Olfactory Bulb.

    PubMed

    Mazo, Camille; Lepousez, Gabriel; Nissant, Antoine; Valley, Matthew T; Lledo, Pierre-Marie

    2016-08-10

    Sensory perception emerges from the confluence of sensory inputs that encode the composition of external environment and top-down feedback that conveys information from higher brain centers. In olfaction, sensory input activity is initially processed in the olfactory bulb (OB), serving as the first central relay before being transferred to the olfactory cortex. In addition, the OB receives dense connectivity from feedback projections, so the OB has the capacity to implement a wide array of sensory neuronal computation. However, little is known about the impact and the regulation of this cortical feedback. Here, we describe a novel mechanism to gate glutamatergic feedback selectively from the anterior olfactory cortex (AOC) to the OB. Combining in vitro and in vivo electrophysiological recordings, optogenetics, and fiber-photometry-based calcium imaging applied to wild-type and conditional transgenic mice, we explore the functional consequences of circuit-specific GABA type-B receptor (GABABR) manipulation. We found that activation of presynaptic GABABRs specifically depresses synaptic transmission from the AOC to OB inhibitory interneurons, but spares direct excitation to principal neurons. As a consequence, feedforward inhibition of spontaneous and odor-evoked activity of principal neurons is diminished. We also show that tunable cortico-bulbar feedback is critical for generating beta, but not gamma, OB oscillations. Together, these results show that GABABRs on cortico-bulbar afferents gate excitatory transmission in a target-specific manner and thus shape how the OB integrates sensory inputs and top-down information. The olfactory bulb (OB) receives top-down inputs from the olfactory cortex that produce direct excitation and feedforward inhibition onto mitral and tufted cells, the principal neurons. The functional role of this feedback and the mechanisms regulating the balance of feedback excitation and inhibition remain unknown. We found that GABAB receptors are

  15. Cortical Feedback Control of Olfactory Bulb Circuits

    PubMed Central

    Boyd, Alison M.; Sturgill, James F.; Poo, Cindy; Isaacson, Jeffry S.

    2013-01-01

    SUMMARY Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition. PMID:23259951

  16. A new dopaminergic nigro-olfactory projection.

    PubMed

    Höglinger, Günter U; Alvarez-Fischer, Daniel; Arias-Carrión, Oscar; Djufri, Miriam; Windolph, Andrea; Keber, Ursula; Borta, Andreas; Ries, Vincent; Schwarting, Rainer K W; Scheller, Dieter; Oertel, Wolfgang H

    2015-09-01

    Parkinson disease (PD) is a neurodegenerative disorder characterized by massive loss of midbrain dopaminergic neurons. Whereas onset of motor impairments reflects a rather advanced stage of the disorder, hyposmia often marks the beginning of the disease. Little is known about the role of the nigro-striatal system in olfaction under physiological conditions and the anatomical basis of hyposmia in PD. Yet, the early occurrence of olfactory dysfunction implies that pathogens such as environmental toxins could incite the disease via the olfactory system. In the present study, we demonstrate a dopaminergic innervation from neurons in the substantia nigra to the olfactory bulb by axonal tracing studies. Injection of two dopaminergic neurotoxins-1-methyl-4-phenylpyridinium and 6-hydroxydopamine-into the olfactory bulb induced a decrease in the number of dopaminergic neurons in the substantia nigra. In turn, ablation of the nigral projection led to impaired olfactory perception. Hyposmia following dopaminergic deafferentation was reversed by treatment with the D1/D2/D3 dopamine receptor agonist rotigotine. Hence, we demonstrate for the first time the existence of a direct dopaminergic projection into the olfactory bulb and identify its origin in the substantia nigra in rats. These observations may provide a neuroanatomical basis for invasion of environmental toxins into the basal ganglia and for hyposmia as frequent symptom in PD.

  17. Olfactory processing in a changing brain.

    PubMed

    Lledo, Pierre-Marie; Gheusi, Gilles

    2003-09-15

    The perception of odorant molecules provides the essential information that allows animals to explore their surrounding. We describe here how the external world of scents may sculpt the activity of the first central relay of the olfactory system, i.e., the olfactory bulb. This structure is one of the few brain areas to continuously replace one of its neuronal populations: the local GABAergic interneurons. How the newly generated neurons integrate into a pre-existing neural network and how basic olfactory functions are maintained when a large percentage of neurons are subjected to continuous renewal, are important questions that have recently received new insights. Furthermore, we shall see how the adult neurogenesis is specifically subjected to experience-dependent modulation. In particular, we shall describe the sensitivity of the bulbar neurogenesis to the activity level of sensory inputs from the olfactory epithelium and, in turn, how this neurogenesis may adjust the neural network functioning to optimize odor information processing. Finally, we shall discuss the behavioral consequences of the bulbar neurogenesis and how it may be appropriate for the sense of smell. By maintaining a constitutive turnover of bulbar interneurons subjected to modulation by environmental cues, we propose that adult ongoing neurogenesis in the olfactory bulb is associated with improved olfactory memory. These recent findings not only provide new fuel for the molecular and cellular bases of sensory perception but should also shed light onto cellular bases of learning and memory.

  18. Olfactory ensheathing glia: their contribution to primary olfactory nervous system regeneration and their regenerative potential following transplantation into the injured spinal cord.

    PubMed

    Franssen, Elske H P; de Bree, Freddy M; Verhaagen, Joost

    2007-11-01

    Olfactory ensheathing glia (OEG) are a specialized type of glia that guide primary olfactory axons from the neuroepithelium in the nasal cavity to the brain. The primary olfactory system is able to regenerate after a lesion and OEG contribute to this process by providing a growth-supportive environment for newly formed axons. In the spinal cord, axons are not able to restore connections after an injury. The effects of OEG transplants on the regeneration of the injured spinal cord have been studied for over a decade. To date, of all the studies using only OEG as a transplant, 41 showed positive effects, while 13 studies showed limited or no effects. There are several contradictory reports on the migratory and axon growth-supporting properties of transplanted OEG. Hence, the regenerative potential of OEG has become the subject of intense discussion. In this review, we first provide an overview of the molecular and cellular characteristics of OEG in their natural environment, the primary olfactory nervous system. Second, their potential to stimulate regeneration in the injured spinal cord is discussed. OEG influence scar formation by their ability to interact with astrocytes, they are able to remyelinate axons and promote angiogenesis. The ability of OEG to interact with scar tissue cells is an important difference with Schwann cells and may be a unique characteristic of OEG. Because of these effects after transplantation and because of their role in primary olfactory system regeneration, the OEG can be considered as a source of neuroregeneration-promoting molecules. To identify these molecules, more insight into the molecular biology of OEG is required. We believe that genome-wide gene expression studies of OEG in their native environment, in culture and after transplantation will ultimately reveal unique combinations of molecules involved in the regeneration-promoting potential of OEG.

  19. Transition from sea to land: olfactory function and constraints in the terrestrial hermit crab Coenobita clypeatus.

    PubMed

    Krång, Anna-Sara; Knaden, Markus; Steck, Kathrin; Hansson, Bill S

    2012-09-07

    The ability to identify chemical cues in the environment is essential to most animals. Apart from marine larval stages, anomuran land hermit crabs (Coenobita) have evolved different degrees of terrestriality, and thus represent an excellent opportunity to investigate adaptations of the olfactory system needed for a successful transition from aquatic to terrestrial life. Although superb processing capacities of the central olfactory system have been indicated in Coenobita and their olfactory system evidently is functional on land, virtually nothing was known about what type of odourants are detected. Here, we used electroantennogram (EAG) recordings in Coenobita clypeatus and established the olfactory response spectrum. Interestingly, different chemical groups elicited EAG responses of opposite polarity, which also appeared for Coenobita compressus and the closely related marine hermit crab Pagurus bernhardus. Furthermore, in a two-choice bioassay with C. clypeatus, we found that water vapour was critical for natural and synthetic odourants to induce attraction or repulsion. Strikingly, also the physiological response was found much greater at higher humidity in C. clypeatus, whereas no such effect appeared in the terrestrial vinegar fly Drosophila melanogaster. In conclusion, our results reveal that the Coenobita olfactory system is restricted to a limited number of water-soluble odourants, and that high humidity is most critical for its function.

  20. Imaging evolutionarily conserved neural networks: preferential activation of the olfactory system by food-related odor.

    PubMed

    Kulkarni, Praveen; Stolberg, Tara; Sullivanjr, J M; Ferris, Craig F

    2012-04-21

    Rodents routinely forge and rely on hippocampal-dependent spatial memory to guide them to sources of caloric rich food in their environment. Has evolution affected the olfactory system and its connections to the hippocampus and limbic cortex, so rodents have an innate sensitivity to energy rich food and their location? To test this notion, we used functional magnetic resonance imaging in awake rats to observe changes in brain activity in response to four odors: benzaldehyde (almond odor), isoamyl acetate (banana odor), methyl benzoate (rosy odor), and limonene (citrus odor). We chose the almond odor because nuts are high in calories and would be expected to convey greater valance as compared to the other odors. Moreover, the standard food chow is devoid of nuts, so laboratory bred rats would not have any previous exposure to this food. Activation maps derived from computational analysis using a 3D segmented rat MRI atlas were dramatically different between odors. Animals exposed to banana, rosy and citrus odors showed modest activation of the primary olfactory system, hippocampus and limbic cortex. However, animals exposed to almond showed a robust increase in brain activity in the primary olfactory system particularly the main olfactory bulb, anterior olfactory nucleus and tenia tecta. The most significant difference in brain activation between odors was observed in the hippocampus and limbic cortex. These findings show that fMRI can be used to identify neural circuits that have an innate sensitivity to environmental stimuli that may help in an animal's survival.

  1. An olfactory cocktail party: figure-ground segregation of odorants in rodents

    PubMed Central

    Rokni, Dan; Hemmelder, Vivian; Kapoor, Vikrant; Murthy, Venkatesh N.

    2014-01-01

    In odorant-rich environments, animals must be able to detect specific odorants of interest against variable backgrounds. However, several studies have suggested that both humans and rodents are very poor at analyzing the components of odorant mixtures, leading to the idea that olfaction is a synthetic sense in which mixtures are perceived holistically. We have developed a behavioral task to directly measure the ability of mice to perceive mixture components and found that mice can be easily trained to detect target odorants embedded in unpredictable and variable mixtures. We imaged the responses of olfactory bulb glomeruli to the individual odors used in the task in mice expressing the Ca++ indicator GCaMP3 in olfactory receptor neurons. By relating behavioral performance to the glomerular response patterns, we found that the difficulty of segregating the target from the background was strongly dependent on the extent of overlap between the representations of the target and the background odors by olfactory receptors. Our study indicates that the olfactory system has powerful analytic abilities that are constrained by the limits of combinatorial neural representation of odorants at the level of the olfactory receptors. PMID:25086608

  2. Transition from sea to land: olfactory function and constraints in the terrestrial hermit crab Coenobita clypeatus

    PubMed Central

    Krång, Anna-Sara; Knaden, Markus; Steck, Kathrin; Hansson, Bill S.

    2012-01-01

    The ability to identify chemical cues in the environment is essential to most animals. Apart from marine larval stages, anomuran land hermit crabs (Coenobita) have evolved different degrees of terrestriality, and thus represent an excellent opportunity to investigate adaptations of the olfactory system needed for a successful transition from aquatic to terrestrial life. Although superb processing capacities of the central olfactory system have been indicated in Coenobita and their olfactory system evidently is functional on land, virtually nothing was known about what type of odourants are detected. Here, we used electroantennogram (EAG) recordings in Coenobita clypeatus and established the olfactory response spectrum. Interestingly, different chemical groups elicited EAG responses of opposite polarity, which also appeared for Coenobita compressus and the closely related marine hermit crab Pagurus bernhardus. Furthermore, in a two-choice bioassay with C. clypeatus, we found that water vapour was critical for natural and synthetic odourants to induce attraction or repulsion. Strikingly, also the physiological response was found much greater at higher humidity in C. clypeatus, whereas no such effect appeared in the terrestrial vinegar fly Drosophila melanogaster. In conclusion, our results reveal that the Coenobita olfactory system is restricted to a limited number of water-soluble odourants, and that high humidity is most critical for its function. PMID:22673356

  3. Divergence in Olfactory Host Plant Preference in D. mojavensis in Response to Cactus Host Use

    PubMed Central

    Stensmyr, Marcus C.; Shann, Jodi; Hansson, Bill S.; Rollmann, Stephanie M.

    2013-01-01

    Divergence in host adaptive traits has been well studied from an ecological and evolutionary perspective, but identification of the proximate mechanisms underlying such divergence is less well understood. Behavioral preferences for host plants are often mediated by olfaction and shifts in preference may be accompanied by changes in the olfactory system. In this study, we examine the evolution of host plant preferences in cactophilic Drosophila mojavensis that feeds and breeds on different cacti throughout its range. We show divergence in electrophysiological responses and olfactory behavior among populations with host plant shifts. Specifically, significant divergence was observed in the Mojave Desert population that specializes on barrel cactus. Differences were observed in electrophysiological responses of the olfactory organs and in behavioral responses to barrel cactus volatiles. Together our results suggest that the peripheral nervous system has changed in response to different ecological environments and that these changes likely contribute to divergence among D. mojavensis populations. PMID:23936137

  4. Divergence in olfactory host plant preference in D. mojavensis in response to cactus host use.

    PubMed

    Date, Priya; Dweck, Hany K M; Stensmyr, Marcus C; Shann, Jodi; Hansson, Bill S; Rollmann, Stephanie M

    2013-01-01

    Divergence in host adaptive traits has been well studied from an ecological and evolutionary perspective, but identification of the proximate mechanisms underlying such divergence is less well understood. Behavioral preferences for host plants are often mediated by olfaction and shifts in preference may be accompanied by changes in the olfactory system. In this study, we examine the evolution of host plant preferences in cactophilic Drosophila mojavensis that feeds and breeds on different cacti throughout its range. We show divergence in electrophysiological responses and olfactory behavior among populations with host plant shifts. Specifically, significant divergence was observed in the Mojave Desert population that specializes on barrel cactus. Differences were observed in electrophysiological responses of the olfactory organs and in behavioral responses to barrel cactus volatiles. Together our results suggest that the peripheral nervous system has changed in response to different ecological environments and that these changes likely contribute to divergence among D. mojavensis populations.

  5. Lectin binding to olfactory system in a shark, Scyliorhinus canicula.

    PubMed

    Franceschini, V; Ciani, F

    1993-01-01

    Lectin histochemical studies were performed on the olfactory system of Scyliorhinus canicula to identify specific glycoconjugates on the cell surface of primary olfactory neurons. The olfactory receptor cells, the olfactory nerve fibers and their terminals in the bulbs were labelled with SBA, BSA-I and BSA-I-B4. The lectin staining patterns indicate that the membranes of small-spotted catshark olfactory neurons had glycoproteins with alpha-galactose residues. This carbohydrate moiety could be related to modulation of the cell-cell interactions in the olfactory system.

  6. Damage to Olfactory Progenitor Cells Is Involved in Cigarette Smoke-Induced Olfactory Dysfunction in Mice.

    PubMed

    Ueha, Rumi; Ueha, Satoshi; Kondo, Kenji; Sakamoto, Takashi; Kikuta, Shu; Kanaya, Kaori; Nishijima, Hironobu; Matsushima, Kouji; Yamasoba, Tatsuya

    2016-03-01

    Exposure to cigarette smoke is a major cause of olfactory dysfunction. However, the underlying mechanisms by which cigarette smoke interferes with the highly regenerative olfactory nerve system remain unclear. To investigate whether cigarette smoke induces olfactory dysfunction by disrupting cell proliferation and cell survival in the olfactory epithelium (OE), we developed a mouse model of smoking that involved intranasal administration of a cigarette smoke solution (CSS). Immunohistological analyses and behavioral testing showed that CSS administration during a period of 24 days reduced the number of olfactory marker protein-positive mature olfactory receptor neurons (ORNs) in the OE and induced olfactory dysfunction. These changes coincided with a reduction in the number of SOX2(+) ORN progenitors and Ki-67(+) proliferating cells in the basal layer of the OE, an increase in the number of caspase-3(+) apoptotic cells, and an increase in the expression of mRNA for the inflammatory cytokines IL-1β and IL-6. Notably, the proliferating ORN progenitor population recovered after cessation of treatment with CSS, resulting in the subsequent restoration of mature ORN numbers and olfaction. These results suggest that SOX2(+) ORN progenitors are targets of CSS-induced impairment of the OE, and that by damaging the ORN progenitor population and increasing ORN death, CSS exposure eventually overwhelms the regenerative capacity of the epithelium, resulting in reduced numbers of mature ORNs and olfactory dysfunction.

  7. Olfactory Fear Conditioning Induces Field Potential Potentiation in Rat Olfactory Cortex and Amygdala

    ERIC Educational Resources Information Center

    Messaoudi, Belkacem; Granjon, Lionel; Mouly, Anne-Marie; Sevelinges, Yannick; Gervais, Remi

    2004-01-01

    The widely used Pavlovian fear-conditioning paradigms used for studying the neurobiology of learning and memory have mainly used auditory cues as conditioned stimuli (CS). The present work assessed the neural network involved in olfactory fear conditioning, using olfactory bulb stimulation-induced field potential signal (EFP) as a marker of…

  8. The location of olfactory receptors within olfactory epithelium is independent of odorant volatility and solubility

    PubMed Central

    2011-01-01

    Background Our objective was to study the pattern of olfactory receptor expression within the dorsal and ventral regions of the mouse olfactory epithelium. We hypothesized that olfactory receptors were distributed based on the chemical properties of their ligands: e.g. receptors for polar, hydrophilic and weakly volatile odorants would be present in the dorsal region of olfactory epithelium; while receptors for non-polar, more volatile odorants would be distributed to the ventral region. To test our hypothesis, we used micro-transplantation of cilia-enriched plasma membranes derived from dorsal or ventral regions of the olfactory epithelium into Xenopus oocytes for electrophysiological characterization against a panel of 100 odorants. Findings Odorants detected by ORs from the dorsal and ventral regions showed overlap in volatility and water solubility. We did not find evidence for a correlation between the solubility and volatility of odorants and the functional expression of olfactory receptors in the dorsal or ventral region of the olfactory epithelia. Conclusions No simple clustering or relationship between chemical properties of odorants could be associated with the different regions of the olfactory epithelium. These results suggest that the location of ORs within the epithelium is not organized based on the physico-chemical properties of their ligands. PMID:21548958

  9. 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. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  10. 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.

  11. Olfactory Fear Conditioning Induces Field Potential Potentiation in Rat Olfactory Cortex and Amygdala

    ERIC Educational Resources Information Center

    Messaoudi, Belkacem; Granjon, Lionel; Mouly, Anne-Marie; Sevelinges, Yannick; Gervais, Remi

    2004-01-01

    The widely used Pavlovian fear-conditioning paradigms used for studying the neurobiology of learning and memory have mainly used auditory cues as conditioned stimuli (CS). The present work assessed the neural network involved in olfactory fear conditioning, using olfactory bulb stimulation-induced field potential signal (EFP) as a marker of…

  12. Recovery of glomerular morphology in the olfactory bulb of young mice after disruption caused by continuous odorant exposure.

    PubMed

    Monjaraz-Fuentes, Fernanda; Millán-Adalco, Diana; Palomero-Rivero, Marcela; Hudson, Robyn; Drucker-Colín, René

    2017-09-01

    Olfactory glomeruli are the first synaptic site of the olfactory system and are formed by the convergence of axons of the same type of sensory neurons onto the olfactory bulbs of the brain. Although the anatomical organization of glomeruli is conserved across species, their particular role in olfactory processing remains uncertain. We studied the composition and maintenance of glomeruli by means of a genetic model, mI7-IRES-tauGFP knock-in young mice, where the cytoskeleton of sensory neurons expressing the mI7 olfactory receptor is tagged with green fluorescent protein. Animals were continuously exposed to heptaldehyde, a cognate ligand of the mI7 receptor, from postnatal days 5-10. We hypothesized that continuous odorant exposure will induce changes in glomerular morphology, and that this can be recovered if the normal odorant environment is reestablished within the early postnatal period. We assessed changes in the distribution of mI7 axons in glomerular morphology, as well as possible changes in the number of the mI7 olfactory sensory neurons. Following odorant exposure the well-defined convergence of mI7 fibers into a single glomerulus was disrupted, producing numerous neighboring glomeruli partially innervated by mI7 fibers. After the normal odor environment was reestablished the number of glomeruli partially innervated by mI7 fibers decreased significantly. Moreover, we found that multiple supernumerary mI7 glomeruli were formed. Our results confirm the significant role of sensory input in glomerular formation and maintenance. Additionally, we show that the developing olfactory system actively maintains glomerular morphology, suggesting the importance of this for olfactory processing. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Differential interactions of sex pheromone and plant odour in the olfactory pathway of a male moth.

    PubMed

    Deisig, Nina; Kropf, Jan; Vitecek, Simon; Pevergne, Delphine; Rouyar, Angela; Sandoz, Jean-Christophe; Lucas, Philippe; Gadenne, Christophe; Anton, Sylvia; Barrozo, Romina

    2012-01-01

    Most animals rely on olfaction to find sexual partners, food or a habitat. The olfactory system faces the challenge of extracting meaningful information from a noisy odorous environment. In most moth species, males respond to sex pheromone emitted by females in an environment with abundant plant volatiles. Plant odours could either facilitate the localization of females (females calling on host plants), mask the female pheromone or they could be neutral without any effect on the pheromone. Here we studied how mixtures of a behaviourally-attractive floral odour, heptanal, and the sex pheromone are encoded at different levels of the olfactory pathway in males of the noctuid moth Agrotis ipsilon. In addition, we asked how interactions between the two odorants change as a function of the males' mating status. We investigated mixture detection in both the pheromone-specific and in the general odorant pathway. We used a) recordings from individual sensilla to study responses of olfactory receptor neurons, b) in vivo calcium imaging with a bath-applied dye to characterize the global input response in the primary olfactory centre, the antennal lobe and c) intracellular recordings of antennal lobe output neurons, projection neurons, in virgin and newly-mated males. Our results show that heptanal reduces pheromone sensitivity at the peripheral and central olfactory level independently of the mating status. Contrarily, heptanal-responding olfactory receptor neurons are not influenced by pheromone in a mixture, although some post-mating modulation occurs at the input of the sexually isomorphic ordinary glomeruli, where general odours are processed within the antennal lobe. The results are discussed in the context of mate localization.

  14. Differential Interactions of Sex Pheromone and Plant Odour in the Olfactory Pathway of a Male Moth

    PubMed Central

    Deisig, Nina; Kropf, Jan; Vitecek, Simon; Pevergne, Delphine; Rouyar, Angela; Sandoz, Jean-Christophe; Lucas, Philippe; Gadenne, Christophe

    2012-01-01

    Most animals rely on olfaction to find sexual partners, food or a habitat. The olfactory system faces the challenge of extracting meaningful information from a noisy odorous environment. In most moth species, males respond to sex pheromone emitted by females in an environment with abundant plant volatiles. Plant odours could either facilitate the localization of females (females calling on host plants), mask the female pheromone or they could be neutral without any effect on the pheromone. Here we studied how mixtures of a behaviourally-attractive floral odour, heptanal, and the sex pheromone are encoded at different levels of the olfactory pathway in males of the noctuid moth Agrotis ipsilon. In addition, we asked how interactions between the two odorants change as a function of the males' mating status. We investigated mixture detection in both the pheromone-specific and in the general odorant pathway. We used a) recordings from individual sensilla to study responses of olfactory receptor neurons, b) in vivo calcium imaging with a bath-applied dye to characterize the global input response in the primary olfactory centre, the antennal lobe and c) intracellular recordings of antennal lobe output neurons, projection neurons, in virgin and newly-mated males. Our results show that heptanal reduces pheromone sensitivity at the peripheral and central olfactory level independently of the mating status. Contrarily, heptanal-responding olfactory receptor neurons are not influenced by pheromone in a mixture, although some post-mating modulation occurs at the input of the sexually isomorphic ordinary glomeruli, where general odours are processed within the antennal lobe. The results are discussed in the context of mate localization. PMID:22427979

  15. Insect enemies of birch

    Treesearch

    James G. Conklin

    1969-01-01

    Native birches are subject to attack by insects at all stages of growth from the germinating seedling to the mature tree. All parts of the tree—roots, stem, branches, foliage, and even the developing seed—may be utilized as feeding sites by insects of one kind or another. An enumeration of the many insects recorded in the literature as feeders on...

  16. Insect transferrins: multifunctional proteins.

    PubMed

    Geiser, Dawn L; Winzerling, Joy J

    2012-03-01

    Many studies have been done evaluating transferrin in insects. Genomic analyses indicate that insects could have more than one transferrin. However, the most commonly studied insect transferrin, Tsf1, shows greatest homology to mammalian blood transferrin. Aspects of insect transferrin structure compared to mammalian transferrin and the roles transferrin serves in insects are discussed in this review. Insect transferrin can have one or two lobes, and can bind iron in one or both. The iron binding ligands identified for the lobes of mammalian blood transferrin are generally conserved in the lobes of insect transferrins that have an iron binding site. Available information supports that the form of dietary iron consumed influences the regulation of insect transferrin. Although message is expressed in several tissues in many insects, fat body is the likely source of hemolymph transferrin. Insect transferrin is a vitellogenic protein that is down-regulated by Juvenile Hormone. It serves a role in transporting iron to eggs in some insects, and transferrin found in eggs appears to be endowed from the female. In addition to the roles of transferrin in iron delivery, this protein also functions to reduce oxidative stress and to enhance survival of infection. Future studies in Tsf1 as well as the other insect transferrins that bind iron are warranted because of the roles of transferrin in preventing oxidative stress, enhancing survival to infections and delivering iron to eggs for development. This article is part of a Special Issue entitled Transferrins: Molecular mechanisms of iron transport and disorders. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Evaluation of long-term occupational exposure to styrene vapor on olfactory function.

    PubMed

    Dalton, Pamela; Lees, Peter S J; Gould, Michele; Dilks, Daniel; Stefaniak, Aleksandr; Bader, Michael; Ihrig, Andreas; Triebig, Gerhard

    2007-10-01

    The primary sensory neurons of the olfactory system are chronically exposed to the ambient environment and may therefore be susceptible to damage from occupational exposure to many volatile chemicals. To investigate whether occupational exposure to styrene was associated with olfactory impairment, we examined olfactory function in 2 groups: workers in a German reinforced-plastics boat-manufacturing facility having a minimum of 2 years of styrene exposure (15-25 ppm as calculated from urinary metabolite concentrations, with historical exposures up to 85 ppm) and a group of age-matched workers from the same facility with lower styrene exposures. The results were also compared with normative data previously collected from healthy, unexposed individuals. Multiple measures of olfactory function were evaluated using a standardized battery of clinical assessments from the Monell-Jefferson Chemosensory Clinical Research Center that included tests of threshold sensitivity for phenylethyl alcohol (PEA) and odor identification ability. Thresholds for styrene were also obtained as a measure of occupational olfactory adaptation. Styrene exposure history was calculated through the use of past biological monitoring results for urinary metabolites of styrene (mandelic acid [MA], phenylglyoxylic acid [PGA]); current exposure was determined for each individual using passive air sampling for styrene and biological monitoring for styrene urinary metabolites. Current mean effective styrene exposure during the day of olfactory testing for the group of workers who worked directly with styrene resins was 18 ppm styrene (standard deviation [SD] = 14), 371 g/g creatinine MA + PGA (SD = 289) and that of the group of workers with lower exposures was 4.8 ppm (SD = 5.2), 93 g/g creatinine MA+PGA (SD = 100). Historic annual average exposures for all workers were greater by a factor of up to 6x. No differences unequivocally attributable to exposure status were observed between the Exposed and

  18. 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

  19. Microanatomy and surgical relevance of the olfactory cistern.

    PubMed

    Wang, Shou-Sen; Zheng, He-Ping; Zhang, Xiang; Zhang, Fa-Hui; Jing, Jun-Jie; Wang, Ru-Mi

    2008-01-01

    All surgical approaches to the anterior skull base involve the olfactory cistern and have the risk of damaging the olfactory nerve. The purpose of this study was to describe the microanatomical features of the olfactory cistern and discuss its surgical relevance. In this study, the olfactory cisterns of 15 formalin-fixed adult cadaveric heads were dissected using a surgical microscope. The results showed that the olfactory cistern was situated in the superficial part of the olfactory sulcus, which separated the gyrus retus from the orbital gyrus. In coronal section, the cistern was triangular in shape; its anterior part enveloped the olfactory bulbs and was high and broad; its posterior part was medial-superior to internal carotid artery and was also much broader. There were one or several openings in the inferior wall of the posterior part in 53.4% of the cisterns. The olfactory cistern communicated with the surrounding subarachnoind cisterns through these openings. The middle part of the olfactory cistern gradually narrowed down posteriorly. Most cisterns were spacious with a few fibrous trabeculas and bands between the olfactory nerves and cistern walls. However 23% of the cisterns were narrow with the cistern walls tightly encasing the olfactory nerve. There were two or three of arterial loops in each olfactory sulcus, from which long, fine olfactory arteries originated. The olfactory arteries coursed along the olfactory nerve and gave off many terminal branches to provide the main blood supply to the olfactory nerve in most cisterns, but the blood supply was in segmental style in a few cisterns. Moreover, the veins of the cistern appeared to be more segmental than the olfactory arteries in most cisterns. These results suggested that most olfactory cisterns are spacious with relatively independent blood supply, and it is reasonable to separate the olfactory tract with its independent blood supply from the frontal lobe by 1-2 cm in the subfrontal approach, the

  20. Deletion of the Bombyx mori odorant receptor co-receptor (BmOrco) impairs olfactory sensitivity in silkworms.

    PubMed

    Liu, Qun; Liu, Wei; Zeng, Baosheng; Wang, Guirong; Hao, Dejun; Huang, Yongping

    2017-07-01

    Olfaction plays an essential role in many important insect behaviors such as feeding and reproduction. To detect olfactory stimuli, an odorant receptor co-receptor (Orco) is required. In this study, we deleted the Orco gene in the Lepidopteran model insect, Bombyx mori, using a binary transgene-based clustered regulatory interspaced short palindromic repeats (CRISPR)/Cas9 system. We initially generated somatic mutations in two targeted sites, from which we obtained homozygous mutants with deletion of a 866 base pair sequence. Because of the flight inability of B. mori, we developed a novel method to examine the adult mating behavior. Considering the specialization in larval feeding, we examined food selection behavior in Orco somatic mutants by the walking trail analysis of silkworm position over time. Single sensillum recordings indicated that the antenna of the homozygous mutant was unable to respond to either of the two sex pheromones, bombykol or bombykal. An adult mating behavior assay revealed that the Orco mutant displayed a significantly impaired mating selection behavior in response to natural pheromone released by a wild-type female moth as well as an 11:1 mixture of bombykol/bombykal. The mutants also exhibited a decreased response to bombykol and, similar to wild-type moths, they displayed no response to bombykal. A larval feeding behavior assay revealed that the Orco mutant displayed defective selection for mulberry leaves and different concentrations of the volatile compound cis-jasmone found in mulberry leaves. Deletion of BmOrco severely disrupts the olfactory system, suggesting that BmOrco is indispensable in the olfactory pathway. The approach used for generating somatic and homozygous mutations also highlights a novel method for mutagenesis. This study on BmOrco function provides insights into the insect olfactory system and also provides a paradigm for agroforestry pest control. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Olfactory cues modulate facial attractiveness.

    PubMed

    Demattè, M Luisa; Osterbauer, Robert; Spence, Charles

    2007-07-01

    We report an experiment designed to investigate whether olfactory cues can influence people's judgments of facial attractiveness. Sixteen female participants judged the attractiveness of a series of male faces presented briefly on a computer monitor using a 9-point visual rating scale. While viewing each face, the participants were simultaneously presented with either clean air or else with 1 of 4 odorants (the odor was varied on a trial-by-trial basis) from a custom-built olfactometer. We included 2 pleasant odors (geranium and a male fragrance) and 2 unpleasant odors (rubber and body odor) as confirmed by pilot testing. The results showed that the participants rated the male faces as being significantly less attractive in the presence of an unpleasant odor than when the faces were presented together with a pleasant odor or with clean air (these conditions did not differ significantly). These results demonstrate the cross-modal influence that unpleasant odors can have on people's judgments of facial attractiveness. Interestingly, this pattern of results was unaffected by whether the odors were body relevant (the body odor and the male fragrance) or not (the rubber and geranium odors).

  2. Compensatory plasticity in the olfactory epithelium: age, timing, and reversibility

    PubMed Central

    Barber, Casey N.

    2015-01-01

    Like other biological systems, olfaction responds “homeostatically” to enduring change in the stimulus environment. This adaptive mechanism, referred to as compensatory plasticity, has been studied almost exclusively in developing animals. Thus it is unknown if this phenomenon is limited to ontogenesis and irreversible, characteristics common to some other forms of plasticity. Here we explore the effects of odor deprivation on the adult mouse olfactory epithelium (OE) using nasal plugs to eliminate nasal airflow unilaterally. Plugs were in place for 2–6 wk after which electroolfactograms (EOGs) were recorded from the occluded and open sides of the nasal cavity. Mean EOG amplitudes were significantly greater on the occluded than on the open side. The duration of plugging did not affect the results, suggesting that maximal compensation occurs within 2 wk or less. The magnitude of the EOG difference between the open and occluded side in plugged mice was comparable to adults that had undergone surgical naris occlusion as neonates. When plugs were removed after 4 wk followed by 2 wk of recovery, mean EOG amplitudes were not significantly different between the always-open and previously plugged sides of the nasal cavity suggesting that this form of plasticity is reversible. Taken together, these results suggest that compensatory plasticity is a constitutive mechanism of olfactory receptor neurons that allows these cells to recalibrate their stimulus-response relationship to fit the statistics of their current odor environment. PMID:26269548

  3. Zincergic innervation from the anterior olfactory nucleus to the olfactory bulb displays plastic responses after mitral cell loss.

    PubMed

    Airado, Carmen; Gómez, Carmela; Recio, Javier S; Baltanás, Fernando C; Weruaga, Eduardo; Alonso, José R

    2008-12-01

    Zinc ions are selectively accumulated in certain neurons (zinc-enriched neurons). The mouse olfactory bulb is richly innervated by zinc-enriched terminals. Here, the plasticity of the zincergic system was studied in the olfactory bulb of the Purkinje Cell Degeneration mutant mouse, an animal with specific postnatal neurodegeneration of the main projection neurons of the olfactory bulb. The analysis focused particularly on the anterior olfactory nucleus since most centrifugal afferents coming to the olfactory bulb arise from this structure. Zinc-enriched terminals in the olfactory bulb and zinc-enriched somata in the anterior olfactory nucleus were visualized after selenite injections. Immunohistochemistry against the vesicular zinc transporter was also carried out to confirm the distribution pattern of zinc-enriched terminals in the olfactory bulb. The mutant mice showed a clear reorganization of zincergic centrifugal projections from the anterior olfactory nucleus to the olfactory bulb. First, all zincergic contralateral neurons projecting to the olfactory bulb were absent in the mutant mice. Second, a significant increase in the number of stained somata was detected in the ipsilateral anterior olfactory nucleus. Since no noticeable changes were observed in the zinc-enriched terminals in the olfactory bulb, it is conceivable that mitral cell loss could induce a reorganization of zinc-enriched projections coming from the anterior olfactory nucleus, probably directed at balancing the global zincergic centrifugal modulation. These results show that zincergic anterior olfactory nucleus cells projecting to the olfactory bulb undergo plastic changes to adapt to the loss of mitral cells in the olfactory bulb of Purkinje Cell Degeneration mutant mice.

  4. An Olfactory Indicator for Acid-Base Titrations.

    ERIC Educational Resources Information Center

    Flair, Mark N.; Setzer, William N.

    1990-01-01

    The use of an olfactory acid-base indicator in titrations for visually impaired students is discussed. Potential olfactory indicators include eugenol, thymol, vanillin, and thiophenol. Titrations performed with each indicator with eugenol proved to be successful. (KR)

  5. Innate responses to putative ancestral hosts: is the attraction of Western flower thrips to pine pollen a result of relict olfactory receptors?

    PubMed

    Abdullah, Zayed S; Ficken, Katherine J; Greenfield, Bethany P J; Butt, Tariq M

    2014-06-01

    Pollinophagy is widely documented in the order Thysanoptera, with representative individuals from six of the nine divergent families known to feed on pollen. Various pollens of the genus Pinus increase the development time, fecundity, longevity, and settling preference of Western Flower Thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Certain species of flower thrips discriminate among pollen types, but no studies have elucidated the olfactory cues that play a role in their pollen preferences. In this study, the volatile organic compounds emitted by pollens of the genus Pinus were elucidated. Various chemicals from pollen headspace elicited electrophysiological responses from WFT antennae. The compound (S)-(-)-verbenone, identified in pollen headspace, attracted WFT in a 4-arm olfactometer. This compound has potential for use in integrated pest management programs against the pest. We present the hypothesis that this polyphagous insect may have retained ancestral 'relict' olfactory receptors through the course of evolution, to explain this attraction to pine pollen. This attraction has allowed the insect to find and exploit an unusual nutrient source that significantly increases its fitness. The study demonstrates how fossil record analysis and subsequent evolutionary knowledge can aid in explaining possibilities as to why some insects sense and respond to chemicals that would otherwise seem peculiar to their ecology, allowing insight into the evolutionary forces that may shape insect olfactory systems over time.

  6. Learning in Insect Pollinators and Herbivores.

    PubMed

    Jones, Patricia L; Agrawal, Anurag A

    2017-01-31

    The relationship between plants and insects is influenced by insects' behavioral decisions during foraging and oviposition. In mutualistic pollinators and antagonistic herbivores, past experience (learning) affects such decisions, which ultimately can impact plant fitness. The higher levels of dietary generalism in pollinators than in herbivores may be an explanation for the differences in learning seen between these two groups. Generalist pollinators experience a high level of environmental variation, which we suggest favors associative learning. Larval herbivores employ habituation and sensitization-strategies useful in their less variable environments. Exceptions to these patterns based on habitats, mobility, and life history provide critical tests of current theory. Relevant plant traits should be under selection to be easily learned and remembered in pollinators and difficult to learn in herbivores. Insect learning thereby has the potential to have an important, yet largely unexplored, role in plant-insect coevolution.

  7. Ecology and evolution of gall-forming insects. Forest Service general technical report

    SciTech Connect

    Price, P.W.; Mattson, W.J.; Baranchikov, Y.N.

    1994-09-21

    ;Partial Contents: Ecology and Population Dynamics; Effects of the Physical Environment on the Ecology of Gall Insects; Biodiversity and Distribution; Genetic Variation in Host Plant Resistance; Evolutionary Perspectives on Gall Insects.

  8. Physical Variables in the Olfactory Stimulation Process

    PubMed Central

    Tucker, Don

    1963-01-01

    Electrical recording from small twigs of nerve in a tortoise showed that olfactory, vomeronasal, and trigeminal receptors in the nose are responsive to various odorants. No one kind of receptor was most sensitive to all odorants. For controlled stimulation, odorant was caused to appear in a stream of gas already flowing through the nose. Of the parameters definable at the naris, temperature, relative humidity, and nature of inert gas had little effect on olfactory responses to amyl acetate, whereas odorant species, odorant concentration, and volume flow rate effectively determined the responses of all nasal chemoreceptors. An intrinsic variable of accessibility to the receptors, particularly olfactory, was demonstrated. Flow dependence of chemoreceptor responses is thought to reflect the necessity for delivery of odorant molecules to receptor sites. Since the olfactory receptors are relatively exposed, plateauing of the response with flow rate for slightly soluble odorants suggests an approach to concentration equilibrium in the overlying mucus with that in the air entering the naris. Accordingly, data for responses to amyl acetate were fitted with Beidler's (1954) taste equation for two kinds of sites being active. The requirement for finite aqueous solubility, if true, suggests substitution of aqueous solutions for gaseous solutions. A suitable medium was found and results conformed to expectations. Olfactory receptors were insensitive to variation of ionic strength, pH, and osmotic pressure. PMID:13994681

  9. Perceptual and Neural Olfactory Similarity in Honeybees

    PubMed Central

    Sandoz, Jean-Christophe

    2005-01-01

    The question of whether or not neural activity patterns recorded in the olfactory centres of the brain correspond to olfactory perceptual measures remains unanswered. To address this question, we studied olfaction in honeybees Apis mellifera using the olfactory conditioning of the proboscis extension response. We conditioned bees to odours and tested generalisation responses to different odours. Sixteen odours were used, which varied both in their functional group (primary and secondary alcohols, aldehydes and ketones) and in their carbon-chain length (from six to nine carbons).The results obtained by presentation of a total of 16 × 16 odour pairs show that (i) all odorants presented could be learned, although acquisition was lower for short-chain ketones; (ii) generalisation varied depending both on the functional group and the carbon-chain length of odours trained; higher generalisation was found between long-chain than between short-chain molecules and between groups such as primary and secondary alcohols; (iii) for some odour pairs, cross-generalisation between odorants was asymmetric; (iv) a putative olfactory space could be defined for the honeybee with functional group and carbon-chain length as inner dimensions; (v) perceptual distances in such a space correlate well with physiological distances determined from optophysiological recordings of antennal lobe activity. We conclude that functional group and carbon-chain length are inner dimensions of the honeybee olfactory space and that neural activity in the antennal lobe reflects the perceptual quality of odours. PMID:15736975

  10. Olfactory phenotypic expression unveils human aging

    PubMed Central

    Mazzatenta, Andrea; Cellerino, Alessandro; Origlia, Nicola; Barloscio, Davide; Sartucci, Ferdinando; Giulio, Camillo Di; Domenici, Luciano

    2016-01-01

    The mechanism of the natural aging of olfaction and its declinein the absence of any overt disease conditions remains unclear. Here, we investigated this mechanism through measurement of one of the parameters of olfactory function, the absolute threshold, in a healthy population from childhood to old age. The absolute olfactory threshold data were collected from an Italian observational study with 622 participants aged 5-105 years. A subjective testing procedure of constant stimuli was used, which was also compared to the ‘staircase’ method, with the calculation of the reliability. The n-butanol stimulus was used as an ascending series of nine molar concentrations that were monitored using an electronic nose. The data were analyzed using nonparametric statistics because of the multimodal distribution. We show that the age-related variations in the absolute olfactory threshold are not continuous; instead, there are multiple olfactory phenotypes. Three distinct age-related phenotypes were defined, termed as ‘juvenile’, ‘mature’ and ‘elder’. The frequency of these three phenotypes depends on age. Our data suggest that the sense of smell does not decrease linearly with aging. Our findings provide the basis for further understanding of olfactory loss as an anticipatory sign of aging and neurodegenerative processes. PMID:27027240

  11. Olfactory and Gustatory Function After Bariatric Surgery.

    PubMed

    Holinski, Franca; Menenakos, Charalambos; Haber, Georg; Olze, Heidi; Ordemann, Juergen

    2015-12-01

    Neither hormone levels nor malabsorption alone fully explains the distinct weight loss after bariatric surgery in morbidly obese patients. Postoperatively, patients regularly report a change in the sense of taste and the development of food aversions. Hedonic and sensory components like olfactory and gustatory stimuli significantly affect appetite and flavour. We prospectively analysed the orthonasal olfactory and gustatory function with psychophysical testing in 44 patients undergoing laparoscopic Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG) or adjustable gastric banding (AGB) and in 23 healthy controls. About 22.7 % of morbidly obese patients were hyposmic, showing significantly lower threshold-discrimination-identification (TDI) scores (p = 0.009) with decreased discrimination and identification ability. In addition, 22.7 % of patients were tested to be limited in gustatory function, with significantly lower taste strip test (TST) scores (p = 0.003). Six months after surgery, olfactory and gustatory function was not different when compared to healthy controls. Due to obesity, patients frequently show impaired olfactory and gustatory function. Six months after laparoscopic bariatric surgery, both chemosensory functions improve. The TDI test is an appropriate tool to measure olfactory function in obese patients.

  12. Receptor guanylyl cyclases in mammalian olfactory function

    PubMed Central

    Zufall, Frank; Munger, Steven D.

    2009-01-01

    The contributions of guanylyl cyclases to sensory signaling in the olfactory system have been unclear. Recently, studies of a specialized subpopulation of olfactory sensory neurons (OSNs) located in the main olfactory epithelium have provided important insights into the neuronal function of one receptor guanylyl cyclase, GC-D. Mice expressing reporters such as β-galactosidase and green fluorescent protein in OSNs that normally express GC-D have allowed investigators to identify these neurons in situ, facilitating anatomical and physiological studies of this sparse neuronal population. The specific perturbation of GC-D function in vivo has helped to resolve the role of this guanylyl cyclase in the transduction of olfactory stimuli. Similar approaches could be useful for the study of the orphan receptor GC-G, which is expressed in another distinct subpopulation of sensory neurons located in the Grueneberg ganglion. In this review, we discuss key findings that have reinvigorated the study of guanylyl cyclase function in the olfactory system. PMID:19941039

  13. Chemical olfactory signals and parenthood in mammals.

    PubMed

    Corona, Rebeca; Lévy, Frédéric

    2015-02-01

    This article is part of a Special Issue "Chemosignals and Reproduction". In mammalian species, odor cues emitted by the newborn are essential to establish maternal behavior at parturition and coordinate early mother-infant interactions. Offspring odors become potent attractive stimuli at parturition promoting the contact with the young to ensure that normal maternal care develops. In some species odors provide a basis for individual recognition of the offspring and highly specialized neural mechanisms for learning the infant signals have evolved. Both the main and the accessory olfactory systems are involved in the onset of maternal care, but only the former contributes to individual odor discrimination of the young. Electrophysiological and neurochemical changes occur in the main olfactory bulb leading to a coding of the olfactory signature of the familiar young. Olfactory neurogenesis could also contribute to motherhood and associated learning. Parturition and interactions with the young influence neurogenesis and some evidence indicates a functional link between olfactory neurogenesis and maternal behavior. Although a simple compound has been found which regulates anogenital licking in the rat, studies identifying the chemical nature of these odors are lacking. Neonatal body odors seem to be particularly salient to human mothers who are able to identify their infant's odors. Recent studies have revealed some neural processing of these cues confirming the importance of mother-young chemical communication in our own species.

  14. Olfactory pathway of the hornet Vespa velutina: New insights into the evolution of the hymenopteran antennal lobe.

    PubMed

    Couto, Antoine; Lapeyre, Benoit; Thiéry, Denis; Sandoz, Jean-Christophe

    2016-08-01

    In the course of evolution, eusociality has appeared several times independently in Hymenoptera, within different families such as Apidae (bees), Formicidae (ants), and Vespidae (wasps and hornets), among others. The complex social organization of eusocial Hymenoptera relies on sophisticated olfactory communication systems. Whereas the olfactory systems of several bee and ant species have been well characterized, very little information is as yet available in Vespidae, although this family represents a highly successful insect group, displaying a wide range of life styles from solitary to eusocial. Using fluorescent labeling, confocal microscopy, and 3D reconstructions, we investigated the organization of the olfactory pathway in queens, workers, and males of the eusocial hornet Vespa velutina. First, we found that caste and sex dimorphism is weakly pronounced in hornets, with regard to both whole-brain morphology and antennal lobe organization, although several male-specific macroglomeruli are present. The V. velutina antennal lobe contains approximately 265 glomeruli (in females), grouped in nine conspicuous clusters formed by afferent tract subdivisions. As in bees and ants, hornets display a dual olfactory pathway, with two major efferent tracts, the medial and the lateral antennal lobe tracts (m- and l-ALT), separately arborizing two antennal lobe hemilobes and projecting to partially different regions of higher order olfactory centers. Finally, we found remarkable anatomical similarities in the glomerular cluster organizations among hornets, ants, and bees, suggesting the possible existence of homologies in the olfactory pathways of these eusocial Hymenoptera. We propose a common framework for describing AL compartmentalization across Hymenoptera and discuss possible evolutionary scenarios. J. Comp. Neurol. 524:2335-2359, 2016. © 2016 Wiley Periodicals, Inc.

  15. Olfactory region schwannoma: Excision with preservation of olfaction.

    PubMed

    Salunke, Pravin; Patra, Devi Prasad; Futane, Sameer; Nada, Ritambhara

    2014-07-01

    Olfactory region schwannomas are rare, but when they occur, they commonly arise from the meningeal branches of the trigeminal nerve and may present without involvement of the olfaction. A 24 year old lady presented with hemifacial paraesthesias. Radiology revealed a large olfactory region enhancing lesion. She was operated through a transbasal with olfactory preserving approach. This manuscript highlights the importance of olfactory preservation in such lesions.

  16. Comparative study of chemical neuroanatomy of the olfactory neuropil in mouse, honey bee, and human.

    PubMed

    Sinakevitch, Irina; Bjorklund, George R; Newbern, Jason M; Gerkin, Richard C; Smith, Brian H

    2017-08-29

    Despite divergent evolutionary origins, the organization of olfactory systems is remarkably similar across phyla. In both insects and mammals, sensory input from receptor cells is initially processed in synaptically dense regions of neuropil called glomeruli, where neural activity is shaped by local inhibition and centrifugal neuromodulation prior to being sent to higher-order brain areas by projection neurons. Here we review both similarities and several key differences in the neuroanatomy of the olfactory system in honey bees, mice, and humans, using a combination of literature review and new primary data. We have focused on the chemical identity and the innervation patterns of neuromodulatory inputs in the primary olfactory system. Our findings show that serotonergic fibers are similarly distributed across glomeruli in all three species. Octopaminergic/tyraminergic fibers in the honey bee also have a similar distribution, and possibly a similar function, to noradrenergic fibers in the mammalian OBs. However, preliminary evidence suggests that human OB may be relatively less organized than its counterparts in honey bee and mouse.

  17. 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

  18. Serotonin is critical for rewarded olfactory short-term memory in Drosophila.

    PubMed

    Sitaraman, Divya; LaFerriere, Holly; Birman, Serge; Zars, Troy

    2012-06-01

    The biogenic amines dopamine, octopamine, and serotonin are critical in establishing normal memories. A common view for the amines in insect memory performance has emerged in which dopamine and octopamine are largely responsible for aversive and appetitive memories. Examination of the function of serotonin begins to challenge the notion of one amine type per memory because altering serotonin function also reduces aversive olfactory memory and place memory levels. Could the function of serotonin be restricted to the aversive domain, suggesting a more specific dopamine/serotonin system interaction? The function of the serotonergic system in appetitive olfactory memory was examined. By targeting the tetanus toxin light chain (TNT) and the human inwardly rectifying potassium channel (Kir2.1) to the serotonin neurons with two different GAL4 driver combinations, the serotonergic system was inhibited. Additional use of the GAL80(ts1) system to control expression of transgenes to the adult stage of the life cycle addressed a potential developmental role of serotonin in appetitive memory. Reduction in appetitive olfactory memory performance in flies with these transgenic manipulations, without altering control behaviors, showed that the serotonergic system is also required for normal appetitive memory. Thus, serotonin appears to have a more general role in Drosophila memory, and implies an interaction with both the dopaminergic and octopaminergic systems.

  19. Epigenetic regulation of olfactory receptor gene expression by the Myb–MuvB/dREAM complex

    PubMed Central

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

    2012-01-01

    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 (CO2) 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 CO2 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. PMID:23105004

  20. Modulation by octopamine of olfactory responses to nonpheromone odorants in the cockroach, Periplaneta americana L.

    PubMed

    Zhukovskaya, Marianna I

    2012-06-01

    Olfactory receptor cells in insects are modulated by neurohormones. Recordings from cockroach olfactory sensilla showed that a subset of sensory neurons increase their responses to selected nonpheromone odorants after octopamine application. With octopamine application, recordings demonstrated increased firing rates by the short but not the long alcohol-sensitive sensilla to the nonpheromone volatile, hexan-1-ol. Within the same sensillum, individual receptor cells are shown to be modulated independently from each other, indicating that the octopamine receptors reside in the receptor not in the accessory cells. A uniform decrease in the amplitude of electroantennogram, which is odorant independent, is suggested to reflect the rise in octopamine concentration in the antennal hemolymph. Perception of general odorants measured as behavioral responses changed qualitatively under octopamine treatment: namely, repulsive hexan-1-ol became neutral, whereas neutral eucalyptol became attractive. Octopamine induced a change in male behavioral responses to general odors that were essentially the same as in the state of sexual arousal. Our findings suggest that sensitivity to odors having different biological significances is modulated selectively at the peripheral as well as other levels of olfactory processing.

  1. Olfactory receptor neurons use gain control and complementary kinetics to encode intermittent odorant stimuli

    PubMed Central

    Gorur-Shandilya, Srinivas; Demir, Mahmut; Long, Junjiajia; Clark, Damon A; Emonet, Thierry

    2017-01-01

    Insects find food and mates by navigating odorant plumes that can be highly intermittent, with intensities and durations that vary rapidly over orders of magnitude. Much is known about olfactory responses to pulses and steps, but it remains unclear how olfactory receptor neurons (ORNs) detect the intensity and timing of natural stimuli, where the absence of scale in the signal makes detection a formidable olfactory task. By stimulating Drosophila ORNs in vivo with naturalistic and Gaussian stimuli, we show that ORNs adapt to stimulus mean and variance, and that adaptation and saturation contribute to naturalistic sensing. Mean-dependent gain control followed the Weber-Fechner relation and occurred primarily at odor transduction, while variance-dependent gain control occurred at both transduction and spiking. Transduction and spike generation possessed complementary kinetic properties, that together preserved the timing of odorant encounters in ORN spiking, regardless of intensity. Such scale-invariance could be critical during odor plume navigation. DOI: http://dx.doi.org/10.7554/eLife.27670.001 PMID:28653907

  2. 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.

  3. Olfactory system gamma oscillations: the physiological dissection of a cognitive neural system

    PubMed Central

    Rojas-Líbano, Daniel

    2008-01-01

    Oscillatory phenomena have been a focus of dynamical systems research since the time of the classical studies on the pendulum by Galileo. Fast cortical oscillations also have a long and storied history in neurophysiology, and olfactory oscillations have led the way with a depth of explanation not present in the literature of most other cortical systems. From the earliest studies of odor-evoked oscillations by Adrian, many reports have focused on mechanisms and functional associations of these oscillations, in particular for the so-called gamma oscillations. As a result, much information is now available regarding the biophysical mechanisms that underlie the oscillations in the mammalian olfactory system. Recent studies have expanded on these and addressed functionality directly in mammals and in the analogous insect system. Sub-bands within the rodent gamma oscillatory band associated with specific behavioral and cognitive states have also been identified. All this makes oscillatory neuronal networks a unique interdisciplinary platform from which to study neurocognitive and dynamical phenomena in intact, freely behaving animals. We present here a summary of what has been learned about the functional role and mechanisms of gamma oscillations in the olfactory system as a guide for similar studies in other cortical systems. PMID:19003484

  4. Changes in the neural representation of odorants after olfactory deprivation in the adult mouse olfactory bulb.

    PubMed

    Kass, Marley D; Pottackal, Joseph; Turkel, Daniel J; McGann, John P

    2013-01-01

    Olfactory sensory deprivation during development has been shown to induce significant alterations in the neurophysiology of olfactory receptor neurons (ORNs), the primary sensory inputs to the brain's olfactory bulb. Deprivation has also been shown to alter the neurochemistry of the adult olfactory system, but the physiological consequences of these changes are poorly understood. Here we used in vivo synaptopHluorin (spH) imaging to visualize odorant-evoked neurotransmitter release from ORNs in adult transgenic mice that underwent 4 weeks of unilateral olfactory deprivation. Deprivation reduced odorant-evoked spH signals compared with sham-occluded mice. Unexpectedly, this reduction was equivalent between ORNs on the open and plugged sides. Changes in odorant selectivity of glomerular subpopulations of ORNs were also observed, but only in ORNs on the open side of deprived mice. These results suggest that naris occlusion in adult mice produces substantial changes in primary olfactory processing which may reflect not only the decrease in olfactory stimulation on the occluded side but also the alteration of response properties on the intact side. We also observed a modest effect of true sham occlusions that included noseplug insertion and removal, suggesting that conventional noseplug techniques may have physiological effects independent of deprivation per se and thus require more careful controls than has been previously appreciated.

  5. The projection from the olfactory epithelium to the olfactory bulb in the salamander, Ambystoma tigrinum.

    PubMed

    Mackay-Sim, A; Nathan, M H

    1984-01-01

    Odor quality may be represented as a "topographic" code of responses of receptor cells throughout the olfactory epithelium, with this code conveyed to the central nervous system by a topographic projection from the olfactory epithelium to the olfactory bulb. There is good evidence for topographic differences in odor-induced receptor cell activity in the tiger salamander but there is no evidence for a topographic epithelium-to-bulb projection in this species. In the present study 3H-leucine autoradiography was used to trace the projections of olfactory receptor neurons in the tiger salamander. Thirteen animals received small injections of tritiated leucine into different regions of the dorsal or the ventral olfactory epithelium, or into the ventrolateral, "vomeronasal organ". The results show that the anterior-to-posterior axes in the dorsal and ventral epithelia are represented along the ventral-to-dorsal axis in the rostral end of the olfactory bulb. The "vomeronasal organ" projects to the caudal end of the bulb. We conclude that the central projection of the olfactory epithelium in the tiger salamander is topographically organised only along the antero-posterior axis and not the medio-lateral axis. Thus epithelial receptor cell activity along the anteroposterior axis would be represented in the glomerular layer of the bulb by activity along its ventro-dorsal axis.

  6. Application of artificial neural networks on mosquito Olfactory Receptor Neurons for an olfactory biosensor.

    PubMed

    Bachtiar, Luqman R; Unsworth, Charles P; Newcomb, Richard D

    2013-01-01

    Various odorants such as carbon dioxide (CO2) and 1-octen-3-ol, underlie the host-seeking behaviors of the major malaria vector Anopheles Gambiae. Highlighted by the olfactory processing strength of the mosquito, such a powerful olfactory sense could serve as the sensors of an artificial olfactory biosensor. In this work, we use the firing rates of the A. Gambiae mosquito Olfactory Receptor Neurons (ORNs), to train an Artificial Neural Network (ANN) for the classification of volatile odorants into their known chemical classes and assess their suitability for an olfactory biosensor. With the implementation of bootstrapping, a more representative result was obtained wherein we demonstrate the training of a hybrid ANN consisting of an array of Multi-Layer Perceptrons (MLPs) with optimal number of hidden neurons. The ANN system was able to correctly class 90.1% of the previously unseen odorants, thus demonstrating very strong evidence for the use of A. Gambiae olfactory receptors coupled with an ANN as an olfactory biosensor.

  7. Expression of olfactory receptors in different life stages and life histories of wild Atlantic salmon (Salmo salar).

    PubMed

    Johnstone, K A; Lubieniecki, K P; Koop, B F; Davidson, W S

    2011-10-01

    It has been hypothesized that salmonids use olfactory cues to return to their natal rivers and streams. However, the key components of the molecular pathway involved in imprinting and homing are still unknown. If odorants are involved in salmon homing migration, then olfactory receptors should play a critical role in the dissipation of information from the environment to the fish. Therefore, we examined the expression profiles of a suite of genes encoding olfactory receptors and other olfactory-related genes in the olfactory rosettes of different life stages in two anadromous and one non-anadromous wild Atlantic salmon populations from Newfoundland, Canada. We identified seven differentially expressed OlfC genes in juvenile anadromous salmon compared to returning adults in both populations of anadromous Atlantic salmon. The salmon from the Campbellton River had an additional 10 genes that were differentially expressed in juveniles compared to returning adults. There was no statistically significant difference in gene expression of any of the genes in the non-anadromous population (P < 0.01). The function of the OlfC gene products is not clear, but they are predicted to be amino acid receptors. Other studies have suggested that salmon use amino acids for imprinting and homing. This study, the first to examine the expression of olfactory-related genes in wild North American Atlantic salmon, has identified seven OlfC genes that may be involved in the imprinting and homeward migration of anadromous Atlantic salmon.

  8. Insects: Bugged Out!

    ERIC Educational Resources Information Center

    Piehl, Kathy

    2011-01-01

    Insects really need no introduction. They have lived on earth much longer than humans and vastly outnumber people and all other animal species combined. People encounter them daily in their houses and yards. Yet, when children want to investigate insects, books can help them start their explorations. "Paleo Bugs" carries readers back to the time…

  9. Insects and Bugs

    ERIC Educational Resources Information Center

    Sutherland, Karen

    2009-01-01

    They have been around for centuries. They sting, they bite. They cause intense itching or painful sores. They even cause allergic reactions and sometimes death. There are two types of insects that are pests to humans--those that sting and those that bite. The insects that bite do so with their mouths and include mosquitoes, chiggers, and ticks.…

  10. Magnetic compasses in insects

    USDA-ARS?s Scientific Manuscript database

    The use of magnetic information for orientation and navigation is a widespread phenomenon in animals. In contrast to navigational systems in vertebrates, our understanding of the mechanisms underlying the insect magnetic perception and use of the information is at an early stage. Some insects use ma...

  11. Great Basin insect outbreaks

    Treesearch

    Barbara Bentz; Diane Alston; Ted Evans

    2008-01-01

    Outbreaks of native and exotic insects are important drivers of ecosystem dynamics in the Great Basin. The following provides an overview of range, forest, ornamental, and agricultural insect outbreaks occurring in the Great Basin and the associated management issues and research needs.

  12. Insects: Bugged Out!

    ERIC Educational Resources Information Center

    Piehl, Kathy

    2011-01-01

    Insects really need no introduction. They have lived on earth much longer than humans and vastly outnumber people and all other animal species combined. People encounter them daily in their houses and yards. Yet, when children want to investigate insects, books can help them start their explorations. "Paleo Bugs" carries readers back to the time…

  13. Insects and Bugs

    ERIC Educational Resources Information Center

    Sutherland, Karen

    2009-01-01

    They have been around for centuries. They sting, they bite. They cause intense itching or painful sores. They even cause allergic reactions and sometimes death. There are two types of insects that are pests to humans--those that sting and those that bite. The insects that bite do so with their mouths and include mosquitoes, chiggers, and ticks.…

  14. Sugarcane insect update

    USDA-ARS?s Scientific Manuscript database

    Insect are an important group of pests affecting sugarcane production. Agricultural consultants play an important role is assisting sugarcane farmers to choose the most appropriated means of managing damaging infestations of insects in their crop. In this presentation, information will be presented ...

  15. Sterile Insect Quality

    USDA-ARS?s Scientific Manuscript database

    This chapter discusses the history of the development of quality control tchnology, the principles and philosophy of assessing insect quality, and the relative importance of the various parameters used to assess insect quality in the context of mass-rearing for the SIT. Quality control is most devel...

  16. Evidence for olfactory search in wandering albatross, Diomedea exulans.

    PubMed

    Nevitt, Gabrielle A; Losekoot, Marcel; Weimerskirch, Henri

    2008-03-25

    Wandering albatrosses (Diomedea exulans) forage over thousands of square kilometers of open ocean for patchily distributed live prey and carrion. These birds have large olfactory bulbs and respond to fishy-scented odors in at-sea trials, suggesting that olfaction plays a role in natural foraging behavior. With the advent of new, fine-scale tracking technologies, we are beginning to explore how birds track prey in the pelagic environment, and we relate these observations to models of odor transport in natural situations. These models suggest that odors emanating from prey will tend to disperse laterally and downwind of the odor source and acquire an irregular and patchy concentration distribution due to turbulent transport. For a seabird foraging over the ocean, this scenario suggests that olfactory search would be facilitated by crosswind flight to optimize the probability of encountering a plume emanating from a prey item, followed by upwind, zigzag flight to localize the prey. By contrast, birds approaching prey by sight would be expected to fly directly to a prey item, irrespective of wind direction. Using high-precision global positioning system (GPS) loggers in conjunction with stomach temperature recorders to simultaneously monitor feeding events, we confirm these predictions in freely ranging wandering albatrosses. We found that initial olfactory detection was implicated in nearly half (46.8%) of all flown approaches preceding prey-capture events, accounting for 45.5% of total prey mass captured by in-flight foraging. These results offer insights into the sensory basis for area-restricted search at the large spatial scales of the open ocean.

  17. Evidence for olfactory search in wandering albatross, Diomedea exulans

    PubMed Central

    Nevitt, Gabrielle A.; Losekoot, Marcel; Weimerskirch, Henri

    2008-01-01

    Wandering albatrosses (Diomedea exulans) forage over thousands of square kilometers of open ocean for patchily distributed live prey and carrion. These birds have large olfactory bulbs and respond to fishy-scented odors in at-sea trials, suggesting that olfaction plays a role in natural foraging behavior. With the advent of new, fine-scale tracking technologies, we are beginning to explore how birds track prey in the pelagic environment, and we relate these observations to models of odor transport in natural situations. These models suggest that odors emanating from prey will tend to disperse laterally and downwind of the odor source and acquire an irregular and patchy concentration distribution due to turbulent transport. For a seabird foraging over the ocean, this scenario suggests that olfactory search would be facilitated by crosswind flight to optimize the probability of encountering a plume emanating from a prey item, followed by upwind, zigzag flight to localize the prey. By contrast, birds approaching prey by sight would be expected to fly directly to a prey item, irrespective of wind direction. Using high-precision global positioning system (GPS) loggers in conjunction with stomach temperature recorders to simultaneously monitor feeding events, we confirm these predictions in freely ranging wandering albatrosses. We found that initial olfactory detection was implicated in nearly half (46.8%) of all flown approaches preceding prey-capture events, accounting for 45.5% of total prey mass captured by in-flight foraging. These results offer insights into the sensory basis for area-restricted search at the large spatial scales of the open ocean. PMID:18326025

  18. Taxis assays measure directional movement of mosquitoes to olfactory cues

    PubMed Central

    2013-01-01

    Background Malaria control methods targeting indoor-biting mosquitoes have limited impact on vectors that feed and rest outdoors. Exploiting mosquito olfactory behaviour to reduce blood-feeding outdoors might be a sustainable approach to complement existing control strategies. Methodologies that can objectively quantify responses to odour under realistic field conditions and allow high-throughput screening of many compounds are required for development of effective odour-based control strategies. Methods The olfactory responses of laboratory-reared Anopheles gambiae in a semi-field tunnel and A. arabiensis females in an outdoor field setting to three stimuli, namely whole human odour, a synthetic blend of carboxylic acids plus carbon dioxide and CO2 alone at four distances up to 100 metres were measured in two experiments using three-chambered taxis boxes that allow mosquito responses to natural or experimentally-introduced odour cues to be quantified. Results Taxis box assays could detect both activation of flight and directional mosquito movement. Significantly more (6-18%) A. arabiensis mosquitoes were attracted to natural human odour in the field up to 30 metres compared to controls, and blended synthetic human odours attracted 20% more A. gambiae in the semi-field tunnel up to 70 metres. Whereas CO2 elicited no response in A. arabiensis in the open field, it was attractive to A. gambiae up to 50 metres (65% attraction compared to 36% in controls). Conclusions We have developed a simple reproducible system to allow for the comparison of compounds that are active over medium- to long-ranges in semi-field or full-field environments. Knowing the natural range of attraction of anopheline mosquitoes to potential blood sources has substantial implications for the design of malaria control strategies, and adds to the understanding of olfactory behaviour in mosquitoes. This experimental strategy could also be extended from malaria vectors to other motile arthropods of

  19. Taxis assays measure directional movement of mosquitoes to olfactory cues.

    PubMed

    Lorenz, Lena M; Keane, Aidan; Moore, Jason D; Munk, Cristina J; Seeholzer, Laura; Mseka, Antony; Simfukwe, Emmanuel; Ligamba, Joseph; Turner, Elizabeth L; Biswaro, Lubandwa R; Okumu, Fredros O; Killeen, Gerry F; Mukabana, Wolfgang R; Moore, Sarah J

    2013-05-03

    Malaria control methods targeting indoor-biting mosquitoes have limited impact on vectors that feed and rest outdoors. Exploiting mosquito olfactory behaviour to reduce blood-feeding outdoors might be a sustainable approach to complement existing control strategies. Methodologies that can objectively quantify responses to odour under realistic field conditions and allow high-throughput screening of many compounds are required for development of effective odour-based control strategies. The olfactory responses of laboratory-reared Anopheles gambiae in a semi-field tunnel and A. arabiensis females in an outdoor field setting to three stimuli, namely whole human odour, a synthetic blend of carboxylic acids plus carbon dioxide and CO(2) alone at four distances up to 100 metres were measured in two experiments using three-chambered taxis boxes that allow mosquito responses to natural or experimentally-introduced odour cues to be quantified. Taxis box assays could detect both activation of flight and directional mosquito movement. Significantly more (6-18%) A. arabiensis mosquitoes were attracted to natural human odour in the field up to 30 metres compared to controls, and blended synthetic human odours attracted 20% more A. gambiae in the semi-field tunnel up to 70 metres. Whereas CO(2) elicited no response in A. arabiensis in the open field, it was attractive to A. gambiae up to 50 metres (65% attraction compared to 36% in controls). We have developed a simple reproducible system to allow for the comparison of compounds that are active over medium- to long-ranges in semi-field or full-field environments. Knowing the natural range of attraction of anopheline mosquitoes to potential blood sources has substantial implications for the design of malaria control strategies, and adds to the understanding of olfactory behaviour in mosquitoes. This experimental strategy could also be extended from malaria vectors to other motile arthropods of medical, veterinary and

  20. [Olfactory dysfunction: correlation of olfactory bulb volume on MRI and objective olfactometry].

    PubMed

    Bauknecht, H-C; Jach, C; Fleiner, F; Sedlmaier, B; Göktas, O

    2010-02-01

    To define the role of olfactory bulb volume measurement by magnetic resonance imaging (MRI) for detecting olfactory dysfunction in comparison with objective olfactometry. Thirty patients with suspected olfactory dysfunction (16 women, 14 men; mean age 52 years, range 20 - 79 years) were examined by MRI and objective olfactometry between January 2006 and January 2009. Olfactory bulb volumes were measured by two neuroradiologists using 3D MR data sets. The olfactory function was categorized as normosmia, hyposmia, and anosmia on the basis of objective olfactometry. Pearson correlation coefficients were calculated for objective olfactometry and olfactory bulb volumes on MRI. ROC analysis was performed to determine whether MRI bulb volumes can serve to predict anosmia or hyposmia. The bulb volumes measured by MRI ranged from 0 to 135.9 mm (3). Based on olfactometry, anosmia was present in 11 patients (total bulb volume of 15.7 +/- 23.3 mm (3)), hyposmia in 9 patients (total bulb volume of 50.0 +/- 25.5 mm (3)), and normosmia in 10 patients (total bulb volume of 110.7 +/- 21.5 mm (3)). There was good correlation (r > 0.9) between objective olfactometry and olfactory bulb volume on MRI. ROC analysis yielded a cut-off value of 32 mm (3) for anosmia, which had a sensitivity of 0.91 and specificity of 0.947. The cut-off value for olfactory dysfunction was 80.7 mm (3) (sensitivity 0.95; specificity of 0.9). The olfactory bulb volume determined by MRI is a suitable parameter for diagnosing complete or partial loss of the sense of smell.

  1. Does post-infectious olfactory loss affect mood more severely than chronic sinusitis with olfactory loss?

    PubMed

    Jung, Yong G; Lee, Jun-Seok; Park, Gi C

    2014-11-01

    Olfactory deficits that develop after viral upper respiratory infection (URI) may have different effects on patient depression index compared to chronic sinusitis with olfactory loss. However, there have been no controlled trials to evaluate the different effects of chronic sinusitis and URI on depression index. Prospective study of 25 subjects in two groups. This study enrolled 25 participants who were diagnosed with post-URI olfactory loss as the study group and 25 patients with chronic sinusitis and olfactory loss as a control group. Control group participants were matched for age, sex, and degree of olfactory loss (threshold, discrimination, and identification [TDI]). We compared the Beck Depression Inventory (BDI) scores of each group and analyzed the correlation between TDI and BDI. The mean BDI score of the post-URI group was significantly higher than that of the control group (14.52 ± 6.59 vs. 9.32 ± 5.23; P=.002). Age, sex, and TDI score did not affect BDI score in the post-URI olfactory loss group. However, BDI score in the sinusitis group was inversely correlated with TDI score (R=-0.423; P=.035), and the BDI score of female subjects (11.00 ± 5.13) was significantly higher than that of male subjects (5.00 ± 2.16; P = .047). Post-URI olfactory loss affected patient mood more severely than chronic sinusitis with a similar degree of olfactory loss. This influence was not affected by sex, age, or TDI score in the post-URI olfactory loss group. 3b. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  2. Neural Correlates of Olfactory Learning: Critical Role of Centrifugal Neuromodulation

    ERIC Educational Resources Information Center

    Fletcher, Max L.; Chen, Wei R.

    2010-01-01

    The mammalian olfactory system is well established for its remarkable capability of undergoing experience-dependent plasticity. Although this process involves changes at multiple stages throughout the central olfactory pathway, even the early stages of processing, such as the olfactory bulb and piriform cortex, can display a high degree of…

  3. Individual olfactory perception reveals meaningful nonolfactory genetic information

    PubMed Central

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

    2015-01-01

    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. PMID:26100865

  4. Neural Correlates of Olfactory Learning: Critical Role of Centrifugal Neuromodulation

    ERIC Educational Resources Information Center

    Fletcher, Max L.; Chen, Wei R.

    2010-01-01

    The mammalian olfactory system is well established for its remarkable capability of undergoing experience-dependent plasticity. Although this process involves changes at multiple stages throughout the central olfactory pathway, even the early stages of processing, such as the olfactory bulb and piriform cortex, can display a high degree of…

  5. 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.

  6. Integration of Insect Infestations into Dynamic Global Vegetation Models Using Insect Functional Types

    NASA Astrophysics Data System (ADS)

    Kim, J. B.; Smith, E.

    2011-12-01

    Many have explored the impact of climate change on insects and explored predictions under future scenarios. But the converse has been limited: no DGVM simulates insect infestation. We are assessing the potential impact of simulating insect infestation processes on DGVMs, and creating a framework for development of insect functional types (IFTs) for integration with DGVMs. Some work have been done devising IFTs for conservation and resource management, but results are limited to qualitative groupings of insect taxa based on resource usage and response to environment. The integration of IFTs into DGVMs would enable exploration of interaction between climate change and vegetation dynamics at the global scale. IFTs have the potential to significantly impact global carbon balance and vegetation distributions, and interaction with other disturbance regimes already modeled in DGVMs (e.g., fire, drought, herbivory). We identify relevant features of existing DGVMs, including spatial and temporal scales, extents, and focuses; how other disturbances are modeled; and model areas where IFTs would link to DGVMs. We identify relevant features of insect models, including hazard and risk models; spatial and temporal resolutions and extents; spatial processes; and commonly used variables. We outline the key considerations, including tradeoffs between accuracy of representation and the breadth of applicability; morphology, physiology, biochemistry, reproductive and demographic characteristics; functional effects vs. functional responses; major axes of specialization that are consistent across environments, biogeographic regions, and major insect taxa; and whether IFTs can be empirically evaluated. We propose major axes to define IFTs, and present a sample IFT, the westwide pine beetle.

  7. Principal Areas of Insect Research

    ERIC Educational Resources Information Center

    Williams, Carroll M.

    1973-01-01

    Research for insect control has been quite complex. However, recent knowledge of using insect hormones against them has opened new vistas for producing insecticides which may be harmless to human population. Current areas of insect research are outlined. (PS)

  8. Insect and arachnid hypersensitivity.

    PubMed

    Bevier, D E

    1999-11-01

    Insect hypersensitivity reactions can have a large number of clinical presentations. The majority of reactions are pruritic and involve the short- or sparsely haired areas of the body. Most are associated with eosinophilic infiltration into the skin, often in a perivascular pattern. The diagnosis may be based on compatible clinical signs and improvement with aggressive insect control and, in some cases, confirmation via provocative exposure. Intradermal, prick, or serum testing for allergen-specific IgE can be used to document the presence of reaginic antibodies against insect allergens. Treatments include avoidance, aggressive insect control, and symptomatic support; in some cases, immunotherapy may be useful in decreasing the severity of clinical reactions to insects.

  9. Reading cinnamon activates olfactory brain regions.

    PubMed

    González, Julio; Barros-Loscertales, Alfonso; Pulvermüller, Friedemann; Meseguer, Vanessa; Sanjuán, Ana; Belloch, Vicente; Avila, César

    2006-08-15

    Some words immediately and automatically remind us of odours, smells and scents, whereas other language items do not evoke such associations. This study investigated, for the first time, the abstract linking of linguistic and odour information using modern neuroimaging techniques (functional MRI). Subjects passively read odour-related words ('garlic', 'cinnamon', 'jasmine') and neutral language items. The odour-related terms elicited activation in the primary olfactory cortex, which include the piriform cortex and the amygdala. Our results suggest the activation of widely distributed cortical cell assemblies in the processing of olfactory words. These distributed neuron populations extend into language areas but also reach some parts of the olfactory system. These distributed neural systems may be the basis of the processing of language elements, their related conceptual and semantic information and the associated sensory information.

  10. Effect of air pollution on olfactory function in residents of Mexico City.

    PubMed

    Hudson, Robyn; Arriola, Aline; Martínez-Gómez, Margarita; Distel, Hans

    2006-01-01

    To our knowledge there has been no study of the effect of everyday air pollution on olfactory function. It was therefore the aim of this study to compare the olfactory performance of long-term residents of Mexico City, an environment with high air pollution, with the olfactory performance of residents of the Mexican state of Tlaxcala, a region geographically similar to Mexico City but with low air pollution. Healthy volunteers [82 Mexico City subjects (MEX), 86 Tlaxcala subjects (TLX)] 20-63 years of age and balanced for age and gender between the two localities were tested for the perception of the odors of everyday beverages presented in squeeze bottles. When tested with ascending concentrations of stimuli in a three-way oddball paradigm, residents of Tlaxcala detected the odors of instant coffee and of an orange drink at significantly lower concentrations than residents of Mexico City. They also performed significantly better in discriminating between the two similar-smelling Mexican beverages horchata and atole in an oddball test. Significant differences between the two populations in overall olfactory performance were apparent in three of the four age classes (20- to 29-, 30- to 39-, and 40- to 49-year-old subjects) but not in the 50-63 years age class. About 10% of MEX subjects compared to about 2% of TLX subjects were judged to have poor olfactory function; all were from the older age classes (mean age: 48.6 years). Thus, air pollution in Mexico City appears to have a substantial impact on olfactory function even in young and middle-aged residents.

  11. Not all sharks are "swimming noses": variation in olfactory bulb size in cartilaginous fishes.

    PubMed

    Yopak, Kara E; Lisney, Thomas J; Collin, Shaun P

    2015-03-01

    Olfaction is a universal modality by which all animals sample chemical stimuli from their environment. In cartilaginous fishes, olfaction is critical for various survival tasks including localizing prey, avoiding predators, and chemosensory communication with conspecifics. Little is known, however, about interspecific variation in olfactory capability in these fishes, or whether the relative importance of olfaction in relation to other sensory systems varies with regard to ecological factors, such as habitat and lifestyle. In this study, we have addressed these questions by directly examining interspecific variation in the size of the olfactory bulbs (OB), the region of the brain that receives the primary sensory projections from the olfactory nerve, in 58 species of cartilaginous fishes. Relative OB size was compared among species occupying different ecological niches. Our results show that the OBs maintain a substantial level of allometric independence from the rest of the brain across cartilaginous fishes and that OB size is highly variable among species. These findings are supported by phylogenetic generalized least-squares models, which show that this variability is correlated with ecological niche, particularly habitat. The relatively largest OBs were found in pelagic-coastal/oceanic sharks, especially migratory species such as Carcharodon carcharias and Galeocerdo cuvier. Deep-sea species also possess large OBs, suggesting a greater reliance on olfaction in habitats where vision may be compromised. In contrast, the smallest OBs were found in the majority of reef-associated species, including sharks from the families Carcharhinidae and Hemiscyllidae and dasyatid batoids. These results suggest that there is great variability in the degree to which these fishes rely on olfactory cues. The OBs have been widely used as a neuroanatomical proxy for olfactory capability in vertebrates, and we speculate that differences in olfactory capabilities may be the result of

  12. Laminar disorganisation of mitral cells in the olfactory bulb does not affect topographic targeting of primary olfactory axons.

    PubMed

    Royal, S J; Gambello, M J; Wynshaw-Boris, A; Key, B; Clarris, H J

    2002-04-05

    Primary olfactory neurons expressing the same odorant receptor protein typically project to topographically fixed olfactory bulb sites. While cell adhesion molecules and odorant receptors have been implicated in guidance of primary olfactory axons, the postsynaptic mitral cells may also have a role in final target selection. We have examined the effect of disorganisation of the mitral cell soma layer in mutant mice heterozygous for the beta-subunit of platelet activating factor acetylhydrolase (Lis1(-/+)) on the targeting of primary olfactory axons. Lis1(-/+) mice display abnormal lamination of neurons in the olfactory bulb. Lis1(-/+) mice were crossed with the P2-IRES-tau:LacZ line of transgenic mice that selectively expresses beta-galactosidase in primary olfactory neurons expressing the P2 odorant receptor. LacZ histochemistry revealed blue-stained P2 axons that targeted topographically fixed glomeruli in these mice in a manner similar to that observed in the parent P2-IRES-tau:LacZ line. Thus, despite the aberrant organisation of postsynaptic mitral cells in Lis1(-/+) mice, primary olfactory axons continued to converge and form glomeruli at correct sites in the olfactory bulb. Next we examined whether challenging primary olfactory axons in adult Lis(-/+) mice with regeneration would affect their ability to converge and form glomeruli. Following partial chemical ablation of the olfactory neuroepithelium with dichlobenil, primary olfactory neurons die and are replaced by newly differentiating neurons that project axons to the olfactory bulb where they converge and form glomeruli. Despite the aberrant mitral cell layer in Lis(-/+) mice, primary olfactory axons continued to converge and form glomeruli during regeneration. Together these results demonstrate that the convergence of primary olfactory axons during development and regeneration is not affected by gross perturbations to the lamination of the mitral cell layer. Thus, these results support evidence from

  13. Scientific Encounters of the Insect World. Reading Activities That Explore Nature's Fascinating Insects. A Good Apple Science Activity Book for Grades 4-7.

    ERIC Educational Resources Information Center

    Embry, Lynn

    Insects comprise the largest group of animals in the world and newly discovered ones are being added to the list every year. The habits of even the most common insects are interesting to observe. This book introduces insects that many children will be able to observe in their environments. Interesting information is presented to help children…

  14. Scientific Encounters of the Insect World. Reading Activities That Explore Nature's Fascinating Insects. A Good Apple Science Activity Book for Grades 4-7.

    ERIC Educational Resources Information Center

    Embry, Lynn

    Insects comprise the largest group of animals in the world and newly discovered ones are being added to the list every year. The habits of even the most common insects are interesting to observe. This book introduces insects that many children will be able to observe in their environments. Interesting information is presented to help children…

  15. Context-dependent olfactory learning monitored by activities of salivary neurons in cockroaches.

    PubMed

    Matsumoto, Chihiro Sato; Matsumoto, Yukihisa; Watanabe, Hidehiro; Nishino, Hiroshi; Mizunami, Makoto

    2012-01-01

    Context-dependent discrimination learning, a sophisticated form of nonelemental associative learning, has been found in many animals, including insects. The major purpose of this research is to establish a method for monitoring this form of nonelemental learning in rigidly restrained insects for investigation of underlying neural mechanisms. We report context-dependent olfactory learning (occasion-setting problem solving) of salivation, which can be monitored as activity changes of salivary neurons in immobilized cockroaches, Periplaneta americana. A group of cockroaches was trained to associate peppermint odor (conditioned stimulus, CS) with sucrose solution reward (unconditioned stimulus, US) while vanilla odor was presented alone without pairing with the US under a flickering light condition (1.0 Hz) and also trained to associate vanilla odor with sucrose reward while peppermint odor was presented alone under a steady light condition. After training, the responses of salivary neurons to the rewarded peppermint odor were significantly greater than those to the unrewarded vanilla odor under steady illumination and those to the rewarded vanilla odor was significantly greater than those to the unrewarded peppermint odor in the presence of flickering light. Similar context-dependent responses were observed in another group of cockroaches trained with the opposite stimulus arrangement. This study demonstrates context-dependent olfactory learning of salivation for the first time in any vertebrate and invertebrate species, which can be monitored by activity changes of salivary neurons in restrained cockroaches.

  16. Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

    PubMed Central

    2012-01-01

    Background Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes. Methods A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambiae, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding. Results Under such experimental conditions An. gambiae females learned very rapidly to associate visual (chequered and white patterns) and olfactory cues (presence and absence of cheese or Citronella smell) with the reinforcing stimuli (bloodmeal quality) and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood) was associated with an innately preferred cue (such as a darker visual pattern). However, the use of too attractive a cue (e.g. Shropshire cheese smell) was counter-productive and decreased learning success. Conclusions The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for An. gambiae's host finding and blood-feeding behaviour with important potential implications for vector control. PMID:22284012

  17. Measuring Olfactory Processes in Mus musculus.

    PubMed

    Schellinck, Heather

    2017-09-04

    This paper briefly reviews the literature that describes olfactory acuity and odor discrimination learning. The results of current studies that examined the role of neurotransmitters in odor discrimination learning are discussed as are those that investigated pattern recognition and models of human disease. The methodology associated with such work is also described and its role in creating disparate results assessed. Recommendations for increasing the reliability and validity of experiments so as to further our understanding of olfactory processes in both healthy mice and those modelling human disease are made throughout the paper. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Olfactory regulation of mosquito–host interactions

    PubMed Central

    Zwiebel, L.J.; Takken, W.

    2011-01-01

    Mosquitoes that act as disease vectors rely upon olfactory cues to direct several important behaviors that are fundamentally involved in establishing their overall vectorial capacity. Of these, the propensity to select humans for blood feeding is arguably the most important of these olfactory driven behaviors in so far as it significantly contributes to the ability of these mosquitoes to transmit pathogens that cause diseases such as dengue, yellow fever and most significantly human malaria. Here, we review significant advances in behavioral, physiological and molecular investigations into mosquito host preference, with a particular emphasis on studies that have emerged in the post-genomic era that seek to combine these approaches. PMID:15242705

  19. Concurrent modulation of neuronal and behavioural olfactory responses to sex and host plant cues in a male moth

    PubMed Central

    Kromann, Sophie H.; Saveer, Ahmed M.; Binyameen, Muhammad; Bengtsson, Marie; Birgersson, Göran; Hansson, Bill S.; Schlyter, Fredrik; Witzgall, Peter; Ignell, Rickard; Becher, Paul G.

    2015-01-01

    Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological condition of the male insect. Unmated males are attracted by upwind flight to sex pheromone released by calling females, as well as to volatiles of lilac flowers and green leaves of the host plant cotton, signalling adult food and mating sites, respectively. Mating temporarily abolishes male attraction to females and host plant odour, but does not diminish attraction to flowers. This behavioural modulation is correlated with a response modulation in the olfactory system, as shown by electro-physiological recordings from antennae and by functional imaging of the antennal lobe, using natural odours and synthetic compounds. An effect of mating on the olfactory responses to pheromone and cotton plant volatiles but not to lilac flowers indicates the presence of functionally independent neural circuits within the olfactory system. Our results indicate that these circuits interconnect and weigh perception of social and habitat odour signals to generate appropriate behavioural responses according to mating state. PMID:25621329

  20. An Insecticide Further Enhances Experience-Dependent Increased Behavioural Responses to Sex Pheromone in a Pest Insect.

    PubMed

    Abrieux, Antoine; Mhamdi, Amel; Rabhi, Kaouther K; Egon, Julie; Debernard, Stéphane; Duportets, Line; Tricoire-Leignel, Hélène; Anton, Sylvia; Gadenne, Christophe

    2016-01-01

    Neonicotinoid insecticides are widely used to protect plants against pest insects, and insecticide residues remaining in the environment affect both target and non-target organisms. Whereas low doses of neonicotinoids have been shown to disturb the behaviour of pollinating insects, recent studies have revealed that a low dose of the neonicotinoid clothianidin can improve behavioural and neuronal sex pheromone responses in a pest insect, the male moth Agrotis ipsilon, and thus potentially improve reproduction. As male moth behaviour depends also on its physiological state and previous experience with sensory signals, we wondered if insecticide effects would be dependent on plasticity of olfactory-guided behaviour. We investigated, using wind tunnel experiments, whether a brief pre-exposure to the sex pheromone could enhance the behavioural response to this important signal in the moth A. ipsilon at different ages (sexually immature and mature males) and after different delays (2 h and 24 h), and if the insecticide clothianidin would interfere with age effects or the potential pre-exposure-effects. Brief pre-exposure to the pheromone induced an age-independent significant increase of sex pheromone responses 24 h later, whereas sex pheromone responses did not increase significantly 2 h after exposure. However, response delays were significantly shorter compared to naïve males already two hours after exposure. Oral treatment with clothianidin increased sex pheromone responses in sexually mature males, confirming previous results, but did not influence responses in young immature males. Males treated with clothianidin after pre-exposure at day 4 responded significantly more to the sex pheromone at day 5 than males treated with clothianidin only and than males pre-exposed only, revealing an additive effect of experience and the insecticide. Plasticity of sensory systems has thus to be taken into account when investigating the effects of sublethal doses of insecticides

  1. An Insecticide Further Enhances Experience-Dependent Increased Behavioural Responses to Sex Pheromone in a Pest Insect

    PubMed Central

    Abrieux, Antoine; Mhamdi, Amel; Rabhi, Kaouther K.; Egon, Julie; Debernard, Stéphane; Duportets, Line; Tricoire-Leignel, Hélène; Anton, Sylvia; Gadenne, Christophe

    2016-01-01

    Neonicotinoid insecticides are widely used to protect plants against pest insects, and insecticide residues remaining in the environment affect both target and non-target organisms. Whereas low doses of neonicotinoids have been shown to disturb the behaviour of pollinating insects, recent studies have revealed that a low dose of the neonicotinoid clothianidin can improve behavioural and neuronal sex pheromone responses in a pest insect, the male moth Agrotis ipsilon, and thus potentially improve reproduction. As male moth behaviour depends also on its physiological state and previous experience with sensory signals, we wondered if insecticide effects would be dependent on plasticity of olfactory-guided behaviour. We investigated, using wind tunnel experiments, whether a brief pre-exposure to the sex pheromone could enhance the behavioural response to this important signal in the moth A. ipsilon at different ages (sexually immature and mature males) and after different delays (2 h and 24 h), and if the insecticide clothianidin would interfere with age effects or the potential pre-exposure-effects. Brief pre-exposure to the pheromone induced an age-independent significant increase of sex pheromone responses 24 h later, whereas sex pheromone responses did not increase significantly 2 h after exposure. However, response delays were significantly shorter compared to naïve males already two hours after exposure. Oral treatment with clothianidin increased sex pheromone responses in sexually mature males, confirming previous results, but did not influence responses in young immature males. Males treated with clothianidin after pre-exposure at day 4 responded significantly more to the sex pheromone at day 5 than males treated with clothianidin only and than males pre-exposed only, revealing an additive effect of experience and the insecticide. Plasticity of sensory systems has thus to be taken into account when investigating the effects of sublethal doses of insecticides

  2. Olfactory Cues Are Subordinate to Visual Stimuli in a Neotropical Generalist Weevil

    PubMed Central

    Otálora-Luna, Fernando; Lapointe, Stephen L.; Dickens, Joseph C.

    2013-01-01

    The tropical root weevil Diaprepes abbreviatus is a major pest of multiple crops in the Caribbean Islands and has become a serious constraint to citrus production in the United States. Recent work has identified host and conspecific volatiles that mediate host- and mate-finding by D. abbreviatus. The interaction of light, color, and odors has not been studied in this species. The responses of male and female D. abbreviatus to narrow bandwidths of visible light emitted by LEDs offered alone and in combination with olfactory stimuli were studied in a specially-designed multiple choice arena combined with a locomotion compensator. Weevils were more attracted to wavelengths close to green and yellow compared with blue or ultraviolet, but preferred red and darkness over green. Additionally, dim green light was preferred over brighter green. Adult weevils were also attracted to the odor of its citrus host + conspecifics. However, the attractiveness of citrus + conspecific odors disappeared in the presence of a green light. Photic stimulation induced males but not females to increase their speed. In the presence of light emitted by LEDs, turning speed decreased and path straightness increased, indicating that weevils tended to walk less tortuously. Diaprepes abbreviatus showed a hierarchy between chemo- and photo-taxis in the series of experiments presented herein, where the presence of the green light abolished upwind anemotaxis elicited by the pheromone + host plant odor. Insight into the strong responses to visual stimuli of chemically stimulated insects may be provided when the amount of information supplied by vision and olfaction is compared, as the information transmission capacity of compound eyes is estimated to be several orders of magnitude higher compared with the olfactory system. Subordination of olfactory responses by photic stimuli should be considered in the design of strategies aimed at management of such insects. PMID:23341926

  3. Plasticity-driven individualization of olfactory coding in mushroom body output neurons

    PubMed Central

    Hige, Toshihide; Aso, Yoshinori; Rubin, Gerald M.; Turner, Glenn C.

    2015-01-01

    Although all sensory circuits ascend to higher brain areas where stimuli are represented in sparse, stimulus-specific activity patterns, relatively little is known about sensory coding on the descending side of neural circuits, as a network converges. In insects, mushroom bodies (MBs) have been an important model system for studying sparse coding in the olfactory system1–3, where this format is important for accurate memory formation4–6. In Drosophila, it has recently been shown that the 2000 Kenyon cells (KCs) of the MB converge onto a population of only 35 MB output neurons (MBONs), that fall into 22 anatomically distinct cell types7,8. Here we provide the first comprehensive view of olfactory representations at the fourth layer of the circuit, where we find a clear transition in the principles of sensory coding. We show that MBON tuning curves are highly correlated with one another. This is in sharp contrast to the process of progressive decorrelation of tuning in the earlier layers of the circuit2,9. Instead, at the population level, odor representations are reformatted so that positive and negative correlations arise between representations of different odors. At the single-cell level, we show that uniquely identifiable MBONs display profoundly different tuning across different animals, but tuning of the same neuron across the two hemispheres of an individual fly was nearly identical. Thus, individualized coordination of tuning arises at this level of the olfactory circuit. Furthermore, we find that this individualization is an active process that requires a learning-related gene, rutabaga. Ultimately, neural circuits have to flexibly map highly stimulus-specific information in sparse layers onto a limited number of different motor outputs. The reformatting of sensory representations we observe here may mark the beginning of this sensory-motor transition in the olfactory system. PMID:26416731

  4. Same same but different: the case of olfactory imagery

    PubMed Central

    Arshamian, Artin; Larsson, Maria

    2014-01-01

    In the present work we present an overview of experimental findings corroborating olfactory imagery observations with the visual and auditory modalities. Overall, the results indicate that imagery of olfactory information share many features with those observed in the primary senses although some major differences are evident. One such difference pertains to the considerable individual differences observed, with the majority being unable to reproduce olfactory information in their mind. Here, we highlight factors that are positively related to an olfactory imagery capacity, such as semantic knowledge, perceptual experience, and olfactory interest that may serve as potential moderators of the large individual variation. PMID:24550862

  5. Accessory Olfactory Bulb Function is Modulated by Input from the Main Olfactory Epithelium

    PubMed Central

    Slotnick, Burton; Restrepo, Diego; Schellinck, Heather; Archbold, Georgina; Price, Stephen; Lin, Weihong

    2013-01-01

    While it is now established that sensory neurons in both the main olfactory epithelium and the vomeronasal organ may be activated by both general and pheromonal odorants, it remains unclear what initiates sampling by the VNO. Anterograde transport of wheat germ agglutinin-horseradish peroxidase was used to determine that adequate intranasal syringing with zinc sulfate interrupted all inputs to the main olfactory bulb but left intact those to the accessory olfactory bulb. Adult male treated mice were frankly anosmic when tested with pheromonal and non-pheromonal odors and failed to engage in aggressive behavior. Treated juvenile females failed to show puberty acceleration subsequent to exposure to bedding from adult males. Activation of the immediate early gene c-Fos and electro-vomeronasogram recording confirmed the integrity of the vomeronasal system in zinc sulfate treated mice. These results support the hypothesis that odor detection by the main olfactory epithelium is required to initiate sampling by the vomeronasal system. PMID:20377623

  6. 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.

  7. Accessory olfactory bulb function is modulated by input from the main olfactory epithelium.

    PubMed

    Slotnick, Burton; Restrepo, Diego; Schellinck, Heather; Archbold, Georgina; Price, Stephen; Lin, Weihong

    2010-03-01

    Although it is now established that sensory neurons in both the main olfactory epithelium and the vomeronasal organ may be activated by both general and pheromonal odorants, it remains unclear what initiates sampling by the vomeronasal organ. Anterograde transport of wheat germ agglutinin-horseradish peroxidase was used to determine that adequate intranasal syringing with zinc sulfate interrupted all inputs to the main olfactory bulb but left intact those to the accessory olfactory bulb. Adult male treated mice were frankly anosmic when tested with pheromonal and non-pheromonal odors and failed to engage in aggressive behavior. Treated juvenile females failed to show puberty acceleration subsequent to exposure to bedding from adult males. Activation of the immediate early gene c-Fos and electrovomeronasogram recording confirmed the integrity of the vomeronasal system in zinc sulfate-treated mice. These results support the hypothesis that odor detection by the main olfactory epithelium is required to initiate sampling by the vomeronasal system.

  8. Linking energetics and overwintering in temperate insects.

    PubMed

    Sinclair, Brent J

    2015-12-01

    Overwintering insects cannot feed, and energy they take into winter must therefore fuel energy demands during autumn, overwintering, warm periods prior to resumption of development in spring, and subsequent activity. Insects primarily consume lipids during winter, but may also use carbohydrate and proteins as fuel. Because they are ectotherms, the metabolic rate of insects is temperature-dependent, and the curvilinear nature of the metabolic rate-temperature relationship means that warm temperatures are disproportionately important to overwinter energy use. This energy use may be reduced physiologically, by reducing the slope or elevation of the metabolic rate-temperature relationship, or because of threshold changes, such as metabolic suppression upon freezing. Insects may also choose microhabitats or life history stages that reduce the impact of overwinter energy drain. There is considerable capacity for overwinter energy drain to affect insect survival and performance both directly (via starvation) or indirectly (for example, through a trade-off with cryoprotection), but this has not been well-explored. Likewise, the impact of overwinter energy drain on growing-season performance is not well understood. I conclude that overwinter energetics provides a useful lens through which to link physiology and ecology and winter and summer in studies of insect responses to their environment.

  9. 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

  10. Corridors and olfactory predator cues affect small mammal behavior.

    SciTech Connect

    Brinkerhoff, Robert Jory; Haddad, Nick M.; Orrock, John L.

    2005-03-30

    Abstract The behavior of prey individuals is influenced by a variety of factors including, but not limited to, habitat configuration, risk of predation, and availability of resources, and these habitat-dependent factors may have interactive effects. We studied the responses of mice to an increase in perceived predation risk in a patchy environment to understand how habitat corridors might affect interactions among species in a fragmented landscape. We used a replicated experiment to investigate corridor-mediated prey responses to predator cues in a network of open habitat patches surrounded by a matrix of planted pine forest. Some of the patches were connected by corridors. We used mark–recapture techniques and foraging trays to monitor the movement, behavior, and abundance of small mammals. Predation threat was manipulated in one-half of the replicates by applying an olfactory predator cue. Corridors synchronized small mammal foraging activity among connected patches. Foraging also was inhibited in the presence of an olfactory predator cue but apparently increased in adjacent connected patches. Small mammal abundance did not change as a result of the predator manipulation and was not influenced by the presence of corridors. This study is among the 1st to indicate combined effects of landscape configuration and predation risk on prey behavior. These changes in prey behavior may, in turn, have cascading effects on community dynamics where corridors and differential predation risk influence movement and patch use.

  11. 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.

  12. Shh-proteoglycan interactions regulate maturation of olfactory glomerular circuitry.

    PubMed

    Persson, Laura; Witt, Rochelle M; Galligan, Meghan; Greer, Paul L; Eisner, Adriana; Pazyra-Murphy, Maria F; Datta, Sandeep R; Segal, Rosalind A

    2014-12-01

    The olfactory system relies on precise circuitry connecting olfactory sensory neurons (OSNs) and appropriate relay and processing neurons of the olfactory bulb (OB). In mammals, the exact correspondence between specific olfactory receptor types and individual glomeruli enables a spatially precise map of glomerular activation that corresponds to distinct odors. However, the mechanisms that govern the establishment and maintenance of the glomerular circuitry are largely unknown. Here we show that high levels of Sonic Hedgehog (Shh) signaling at multiple sites enable refinement and maintenance of olfactory glomerular circuitry. Mice expressing a mutant version of Shh (Shh(Ala/Ala)), with impaired binding to proteoglycan co-receptors, exhibit disproportionately small olfactory bulbs containing fewer glomeruli. Notably, in mutant animals the correspondence between individual glomeruli and specific olfactory receptors is lost, as olfactory sensory neurons expressing different olfactory receptors converge on the same glomeruli. These deficits arise at late stages in post-natal development and continue into adulthood, indicating impaired pruning of erroneous connections within the olfactory bulb. In addition, mature Shh(Ala/Ala) mice exhibit decreased proliferation in the subventricular zone (SVZ), with particular reduction in neurogenesis of calbindin-expressing periglomerular cells. Thus, Shh interactions with proteoglycan co-receptors function at multiple locations to regulate neurogenesis and precise olfactory connectivity, thereby promoting functional neuronal circuitry.

  13. Shh-Proteoglycan Interactions Regulate Maturation of Olfactory Glomerular Circuitry

    PubMed Central

    Persson, Laura; Witt, Rochelle M.; Galligan, Meghan; Greer, Paul L.; Eisner, Adriana; Pazyra-Murphy, Maria F.; Datta, Sandeep R.; Segal, Rosalind A.

    2014-01-01

    The olfactory system relies on precise circuitry connecting olfactory sensory neurons (OSNs) and appropriate relay and processing neurons of the olfactory bulb (OB). In mammals, the exact correspondence between specific olfactory receptor types and individual glomeruli enables a spatially precise map of glomerular activation that corresponds to distinct odors. However, the mechanisms that govern the establishment and maintenance of the glomerular circuitry are largely unknown. Here we show that high levels of Sonic Hedgehog (Shh) signaling at multiple sites enable refinement and maintenance of olfactory glomerular circuitry. Mice expressing a mutant version of Shh (ShhAla/Ala), with impaired binding to proteoglycan co-receptors, exhibit disproportionately small olfactory bulbs containing fewer glomeruli. Notably, in mutant animals the correspondence between individual glomeruli and specific olfactory receptors is lost, as olfactory sensory neurons expressing different olfactory receptors converge on the same glomeruli. These deficits arise at late stages in post-natal development and continue into adulthood, indicating impaired pruning of erroneous connections within the olfactory bulb. In addition, mature ShhAla/Ala mice exhibit decreased proliferation in the subventricular zone (SVZ), with particular reduction in neurogenesis of calbindin-expressing periglomerular cells. Thus, Shh interactions with proteoglycan co-receptors function at multiple locations to regulate neurogenesis and precise olfactory connectivity, thereby promoting functional neuronal circuitry. PMID:24913191

  14. 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

  15. Beneficial Insects and Insect Pollinators on Milkweed in South Georgia

    USDA-ARS?s Scientific Manuscript database

    Insect pollinators are essential for the reproduction of more than two-thirds of the world’s crops, and beneficial insects play an important role in managing pest insects in agricultural farmscapes. These insects depend on nectar for their survival in these farmscapes. The flowers of tropical milkwe...

  16. Olfactory ensheathing cells: biology in neural development and regeneration.

    PubMed

    Su, Zhida; He, Cheng

    2010-12-01

    Olfactory ensheathing cells (OECs) constitute a unique population of glia that accompany and ensheath the primary olfactory axons. They are thought to be critical for spontaneous growth of olfactory axons within the developing and adult olfactory nervous system, and have recently emerged as potential candidates for cell-mediated repair of neural injuries. Here, based on the current research, we give an overview of the biology of OECs in neural development and regeneration. This review starts with a detailed description of the cellular and molecular biological properties of OECs. Their functions in olfactory neurogenesis, olfactory axonal growth and olfactory bulb formation are sequently discussed. We also describe therapeutic applications of OECs for the treatment of a variety of neural lesions, including spinal cord injury, stroke, degenerative diseases, and PNS injuries. Finally, we address issues that may foster a better understanding of OECs in neural development and regeneration. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Sphenoid esthesioneuroblastoma arising from the hindmost olfactory filament.

    PubMed

    Matsunaga, Mami; Nakagawa, Takayuki; Sakamoto, Tatsunori; Ito, Juichi

    2015-04-01

    Esthesioneuroblastoma (ENB), or olfactory neuroblastoma, is a rare malignant neoplasm arising from the olfactory neuroepithelium. Typically, ENBs are found in the olfactory cleft with extension to the ethmoid sinuses or anterior skull base. Here we report a case of ENB located in the sphenoid sinus, which had been considered as an ectopic ENB. However, endoscopic resection revealed the continuity of the tumor with the hindmost olfactory filament. The present case suggests that an ENB in the sphenoid sinus was not ectopic, but arose from the normal olfactory neuroepithelium. This continuity of the ENB with this filament indicated that the tumor was not ectopic, and that there was possible tumor invasion into the olfactory neuroepithelium in the cribriform niche. Therefore, pathological examination of the olfactory neuroepithelium in the cribriform niche may be necessary in case of sphenoid ENBs.

  18. Olfactory perception, communication, and the nose-to-brain pathway.

    PubMed

    Stockhorst, Ursula; Pietrowsky, Reinhard

    2004-10-30

    The present paper's aim is of to give an overview about the basic knowledge as well as actual topics of olfaction--with a special regard on behavior. We summarize different functions of the nose and the olfactory system in human physiology and psychology. We will first describe the functional anatomy of the olfactory system in man. Afterwards, the function of the olfactory system will be viewed from an evolutionary and phylogenetic perspective. We will further outline the main features of olfactory perception, and will show how olfactory perception is influenced by learning. Olfactory signals are relevant stimuli that affect communication. Consequently, the role of the olfactory system in social interaction and mood will be described and gender differences will be addressed. Finally, the function of the nose as an interface to the brain, including implications for pharmacology, will be discussed.

  19. Insect Repellents: Modulators of Mosquito Odorant Receptor Activity

    PubMed Central

    Bohbot, Jonathan D.; Dickens, Joseph C.

    2010-01-01

    Background DEET, 2-undecanone (2-U), IR3535 and Picaridin are widely used as insect repellents to prevent interactions between humans and many arthropods including mosquitoes. Their molecular action has only recently been studied, yielding seemingly contradictory theories including odorant-dependent inhibitory and odorant-independent excitatory activities on insect olfactory sensory neurons (OSNs) and odorant receptor proteins (ORs). Methodology/Principal Findings Here we characterize the action of these repellents on two Aedes aegypti ORs, AaOR2 and AaOR8, individually co-expressed with the common co-receptor AaOR7 in Xenopus oocytes; these ORs are respectively activated by the odors indole (AaOR2) and (R)-(−)-1-octen3-ol (AaOR8), odorants used to locate oviposition sites and host animals. In the absence of odorants, DEET activates AaOR2 but not AaOR8, while 2-U activates AaOR8 but not AaOR2; IR3535 and Picaridin do not activate these ORs. In the presence of odors, DEET strongly inhibits AaOR8 but not AaOR2, while 2-U strongly inhibits AaOR2 but not AaOR8; IR3535 and Picaridin strongly inhibit both ORs. Conclusions/Significance These data demonstrate that repellents can act as olfactory agonists or antagonists, thus modulating OR activity, bringing concordance to conflicting models. PMID:20725637

  20. The diversified function and potential therapy of ectopic olfactory receptors in non-olfactory tissues.

    PubMed

    Chen, Zhe; Zhao, Hong; Fu, Nian; Chen, Linxi

    2017-03-24

    Olfactory receptors (ORs) are mainly distributed in olfactory neurons and play a key role in detecting volatile odorants, eventually resulting in the production of smell perception. Recently, it is also reported that ORs are expressed in non-olfactory tissues including heart, lung, sperm, skin, and cancerous tissues. Interestingly, ectopic ORs are associated with the development of diseases in non-olfactory tissues. For instance, ectopic ORs initiate the hypoxic ventilatory responses and maintain the oxygen homeostasis of breathing in the carotid body when oxygen levels decline. Ectopic ORs induce glucose homeostasis in diabetes. Ectopic ORs regulate systemic blood pressure by increasing renin secretion and vasodilation. Ectopic ORs participate in the process of tumor cell proliferation, apoptosis, metastasis, and invasiveness. Ectopic ORs accelerate the occurrence of obesity, angiogenesis and wound-healing processes. Ectopic ORs affect fetal hemoglobin levels in sickle cell anemia and thalassemia. Finally, we also elaborate some ligands targeting for ORs. Obviously, the diversified function and related signal pathway of ectopic ORs may play a potential therapeutic target in non-olfactory tissues. Thus, this review focuses on the latest research results about the diversified function and therapeutic potential of ectopic ORs in non-olfactory tissues. © 2017 Wiley Periodicals, Inc.

  1. Encoding olfactory signals via multiple chemosensory systems.

    PubMed

    Ma, Minghong

    2007-01-01

    Most animals have evolved multiple olfactory systems to detect general odors as well as social cues. The sophistication and interaction of these systems permit precise detection of food, danger, and mates, all crucial elements for survival. In most mammals, the nose contains two well described chemosensory apparatuses (the main olfactory epithelium and the vomeronasal organ), each of which comprises several subtypes of sensory neurons expressing distinct receptors and signal transduction machineries. In many species (e.g., rodents), the nasal cavity also includes two spatially segregated clusters of neurons forming the septal organ of Masera and the Grueneberg ganglion. Results of recent studies suggest that these chemosensory systems perceive diverse but overlapping olfactory cues and that some neurons may even detect the pressure changes carried by the airflow. This review provides an update on how chemosensory neurons transduce chemical (and possibly mechanical) stimuli into electrical signals, and what information each system brings into the brain. Future investigation will focus on the specific ligands that each system detects with a behavioral context and the processing networks that each system involves in the brain. Such studies will lead to a better understanding of how the multiple olfactory systems, acting in concert, offer a complete representation of the chemical world.

  2. Functional Neuroanatomy of "Drosophila" Olfactory Memory Formation

    ERIC Educational Resources Information Center

    Guven-Ozkan, Tugba; Davis, Ronald L.

    2014-01-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying "Drosophila" learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive…

  3. Acid sensing by the Drosophila olfactory system.

    PubMed

    Ai, Minrong; Min, Soohong; Grosjean, Yael; Leblanc, Charlotte; Bell, Rati; Benton, Richard; Suh, Greg S B

    2010-12-02

    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.

  4. Propagation of olfactory information in Drosophila.

    PubMed

    Root, Cory M; Semmelhack, Julia L; Wong, Allan M; Flores, Jorge; Wang, Jing W

    2007-07-10

    Investigating how information propagates between layers in the olfactory system is an important step toward understanding the olfactory code. Each glomerular output projection neuron (PN) receives two sources of input: the olfactory receptor neurons (ORNs) of the same glomerulus and interneurons that innervate many glomeruli. We therefore asked how these inputs interact to produce PN output. We used receptor gene mutations to silence all of the ORNs innervating a specific glomerulus and recorded PN activity with two-photon calcium imaging and electrophysiology. We found evidence for balanced excitatory and inhibitory synaptic inputs but saw little or no response in the absence of direct ORN input. We next asked whether any transformation of activity occurs at successive layers of the antennal lobe. We found a strong link between PN firing and dendritic calcium elevation, the latter of which is tightly correlated with calcium activity in ORN axons, supporting the idea of glomerular propagation of olfactory information. Finally, we showed that odors are represented by a sparse population of PNs. Together, these results are consistent with the idea that direct receptor input provides the main excitatory drive to PNs, whereas interneurons modulate PN output. Balanced excitatory and inhibitory interneuron input may provide a mechanism to adjust PN sensitivity.

  5. Adult Neurogenesis and the Olfactory System

    PubMed Central

    Whitman, Mary C.; Greer, Charles A.

    2009-01-01

    Though initially described in the early 1960s, it is only within the past decade that the concept of continuing adult neurogenesis has gained widespread acceptance. Neuroblasts from the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) into the olfactory bulb, where they differentiate into interneurons. Neuroblasts from the subgranular zone (SGZ) of the hippocampal formation show relatively little migratory behavior, and differentiate into dentate gyrus granule cells. In sharp contrast to embryonic and perinatal development, these newly differentiated neurons must integrate into a fully functional circuit, without disrupting ongoing performance. Here, after a brief historical overview and introduction to olfactory circuitry, we review recent advances in the biology of neural stem cells, mechanisms of migration in the RMS and olfactory bulb, differentiation and survival of new neurons, and finally mechanisms of synaptic integration. Our primary focus is on the olfactory system, but we also contrast the events occurring there with those in the hippocampal formation. Although both SVZ and SGZ neurogenesis are involved in some types of learning, their full functional significance remains unclear. Since both systems offer models of integration of new neuroblasts, there is immense interest in using neural stem cells to replace neurons lost in injury or disease. Though many questions remain unanswered, new insights appear daily about adult neurogenesis, regulatory mechanisms, and the fates of the progeny. We discuss here some of the central features of these advances, as well as speculate on future research directions. PMID:19615423

  6. Functional Neuroanatomy of "Drosophila" Olfactory Memory Formation

    ERIC Educational Resources Information Center

    Guven-Ozkan, Tugba; Davis, Ronald L.

    2014-01-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying "Drosophila" learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive…

  7. Sex differences in the human olfactory system.

    PubMed

    Garcia-Falgueras, Alicia; Junque, Carme; Giménez, Mónica; Caldú, Xavier; Segovia, Santiago; Guillamon, Antonio

    2006-10-20

    The olfactory system (accessory) implicated in reproductive physiology and behavior in mammals is sexually dimorphic. These brain sex differences present two main characteristics: they are seen in neural circuits related to sexual behavior and sexual physiology and they take one of two opposite morphological patterns (male>female or female>male). The present work reports sex differences in the olfactory system in a large homogeneous sample of men (40) and women (51) using of voxel-based morphology. Gray matter concentration showed sexual dimorphism in several olfactory regions. Women have a higher concentration in the orbitofrontal cortex involving Brodmann's areas 10, 11 and 25 and temporomedial cortex (bilateral hippocampus and right amygdala), as well as their left basal insular cortex. In contrast, men show a higher gray matter concentration in the left entorhinal cortex (Brodmann's area 28), right ventral pallidum, dorsal left insular cortex and a region of the orbitofrontal cortex (Brodmann's area 25). This study supports the hypothesis that the mammalian olfactory system is a sexually dimorphic network and provides a theoretical framework for the morphofunctional approach to sex differences in the human brain.

  8. Immunocytochemical characterisation of olfactory ensheathing cells of zebrafish

    PubMed Central

    Lazzari, Maurizio; Bettini, Simone; Franceschini, Valeria

    2014-01-01

    Continuous lifelong neurogenesis is typical of the vertebrate olfactory system. The regenerative ability of olfactory receptor neurons is dependent on the glial cell type specific to the olfactory pathway, designated ‘olfactory ensheathing cells'. Several studies to date have focused on mammalian olfactory ensheathing cells, owing to their potential roles in cell-based therapy for spinal cord injury repair. However, limited information is available regarding this glial cell type in non-mammalian vertebrates, particularly anamniotes. In the current immunocytochemical study, we analysed the features of olfactory ensheathing cells in the zebrafish, Danio rerio. Fish provide a good model for studying glial cells associated with the olfactory pathway of non-mammalian vertebrates. In particular, zebrafish has numerous valuable features that enable its use as a prime model organism for genetic, neurobiological and developmental studies, as well as toxicology and genomics research. Paraffin sections from decalcified heads of zebrafish were processed immunocytochemically to detect proteins used in the research on mammalian olfactory ensheathing cells, including glial fibrillary acid protein (GFAP), S100, neural cell adhesion molecule (NCAM), polysialylated NCAM (PSA-NCAM), vimentin (VIM), p75NTR and galactin (Gal)-1. Notably, GFAP, S100, NCAM and Gal-1 were clearly observed, whereas no vimentin staining was detected. Weak immunostaining for PSA-NCAM and p75NTR was evident. Moreover the degree of marker expression was not uniform in various tracts of the zebrafish olfactory pathway. The immunostaining patterns of the zebrafish olfactory system are distinct from those of other fish to some extent, suggesting interspecific differences. We also showed that the olfactory pathway of zebrafish expresses markers of mammalian olfactory ensheathing cells. The olfactory systems of vertebrates have similarities but there are also marked variations between them. The issue of whether

  9. Allergic risks of consuming edible insects: A systematic review.

    PubMed

    Ribeiro, José Carlos; Cunha, Luís Miguel; Sousa-Pinto, Bernardo; Fonseca, João

    2017-06-27

    The expected future demand for food and animal-derived protein will require environment-friendly novel food sources with high nutritional value. Insects may be one of such novel food sources. However, there needs to be an assessment of the risks associated with their consumption, including allergic risks. Therefore, we performed a systematic review aiming to analyse current data available regarding the allergic risks of consuming insects. We reviewed all reported cases of food allergy to insects, and studied the possibility of cross-reactivity and co-sensitisation between edible insects, crustaceans and house dust mites. We analysed a total of 25 articles - eight assessing the cross-reactivity/co-sensitisation between edible insects, crustaceans and house dust mites; three characterizing allergens in edible insects and 14 case reports, describing case series or prevalence studies of food allergy caused by insects. Cross-reactivity/co-sensitisation between edible insects and crustaceans seems to be clinically relevant, while it is still unknown if co-sensitisation between house dust mites and edible insects can lead to a food allergy. Additionally, more information is also needed about the molecular mechanisms underlying food allergy to insects, although current data suggest that an important role is played by arthropod pan-allergens such as tropomyosin or arginine kinase. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Nonlinear flight dynamics and stability of hovering model insects

    PubMed Central

    Liang, Bin; Sun, Mao

    2013-01-01

    Current analyses on insect dynamic flight stability are based on linear theory and limited to small disturbance motions. However, insects' aerial environment is filled with swirling eddies and wind gusts, and large disturbances are common. Here, we numerically solve the equations of motion coupled with the Navier–Stokes equations to simulate the large disturbance motions and analyse the nonlinear flight dynamics of hovering model insects. We consider two representative model insects, a model hawkmoth (large size, low wingbeat frequency) and a model dronefly (small size, high wingbeat frequency). For small and large initial disturbances, the disturbance motion grows with time, and the insects tumble and never return to the equilibrium state; the hovering flight is inherently (passively) unstable. The instability is caused by a pitch moment produced by forward/backward motion and/or a roll moment produced by side motion of the insect. PMID:23697714

  11. Feeding the insect industry

    USDA-ARS?s Scientific Manuscript database

    This article reports the use of insect colloidal artificial diets suitable for the rearing of economically important arthropods, such as Lygus lineolaris, Lygus hesperus, Coleomegilla maculata, and Phytoseiulus persimilis The different diets contain key nutrients such as proteins, carbohydrates, vit...

  12. Insect Bites and Stings

    MedlinePlus

    ... they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito and ... have severe allergic reactions to insect bites and stings (such as anaphylaxis), carry an emergency epinephrine kit

  13. [Comparison of therapeutic effects of olfactory ensheathing cells derived from olfactory mucosa or olfactory bulb on spinal cord injury mouse models].

    PubMed

    Wang, Libin; Yang, Ping; Liang, Xueyun; Ma, Lijun; Wei, Jun

    2014-04-01

    To isolate and culture olfactory ensheathing cells from different origins, compare their different biological characteristics, and evaluate their therapeutic effect on spinal cord injury mouse models. The olfactory ensheathing cells from olfactory mucosa or olfactory bulb were isolated and cultured by differential adhesion method. The expressions of S100 and P75 proteins were examined by immunofluorescence staining; their growth curves were drawn by MTT colorimetric assay; the secretion of neurotrophic factors, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and neurotrophin-3 (NT-3) was measured by ELISA; the gene expressions of BDNF, NGF, NT-3, neurotrophin-4 (NT-4), growth-associated protein 43 (GAP-43), and microtubule-associated protein (MAP-2) were quantified by real-time PCR; the therapeutic effect on spinal cord injury mouse models was evaluated by Basso, Beattie and Bresnahan (BBB) locomotor rating scale, which had been carried out daily for 8 weeks after the olfactory ensheathing cells of the two different origins were respectively grafted to the mouse models. The two types of olfactory ensheathing cells showed bipolar or tripolar shape; both of them were S100 and P75 protein positive; both of them expressing the gene of BDNF, NGF, NT-3, and NT-4; the olfactory bulb-derived cells did not express MAP-2, but it highly expressed GAP-43 gene; the olfactory mucosa-derived cells displayed a low expression of MAP-2 and GAP-43; the growth speed of olfactory bulb-derived cells was faster than that of the olfactory mucosa-derived cells. Both of them could secrete BDNF, NGF, and NT-3, but the neurotrophic factor levels secreted in the olfactory mucosa-derived cells were higher. The daily neurological BBB scoring showed that the therapeutic effect of olfactory mucosa-derived cells on spinal cord injury mouse models was better than that of the olfactory bulb-derived cells. There exist biological differences between the olfactory mucosa

  14. Evolution of the Insects

    NASA Astrophysics Data System (ADS)

    Grimaldi, David; Engel, Michael S.

    2005-05-01

    This book chronicles the complete evolutionary history of insects--their living diversity and relationships as well as 400 million years of fossils. Introductory sections cover the living species diversity of insects, methods of reconstructing evolutionary relationships, basic insect structure, and the diverse modes of insect fossilization and major fossil deposits. Major sections then explore the relationships and evolution of each order of hexapods. The volume also chronicles major episodes in the evolutionary history of insects from their modest beginnings in the Devonian and the origin of wings hundreds of millions of years before pterosaurs and birds to the impact of mass extinctions and the explosive radiation of angiosperms on insects, and how they evolved into the most complex societies in nature. Whereas other volumes focus on either living species or fossils, this is the first comprehensive synthesis of all aspects of insect evolution. Illustrated with 955 photo- and electron- micrographs, drawings, diagrams, and field photos, many in full color and virtually all of them original, this reference will appeal to anyone engaged with insect diversity--professional entomologists and students, insect and fossil collectors, and naturalists. David Grimaldi and Michael S. Engel have collectively published over 200 scientific articles and monographs on the relationships and fossil record of insects, including 10 articles in the journals Science, Nature, and Proceedings of the National Academy of Sciences. David Grimaldi is curator in the Division of Invertebrate Zoology, American Museum of Natural History and adjunct professor at Cornell University, Columbia University, and the City University of New York. David Grimaldi has traveled in 40 countries on 6 continents, collecting and studying recent species of insects and conducting fossil excavations. He is the author of Amber: Window to the Past (Abrams, 2003). Michael S. Engel is an assistant professor in the

  15. Important Insect Pests of Fruit - Important Insect Pests of Nuts - Field Crop Insect Pests - Insect Pests of Vegetable Crops.

    ERIC Educational Resources Information Center

    Gesell, Stanley G.; And Others

    This document consists of four agriculture extension service publications from Pennsylvania State University. The titles are: (1) Important Insect Pests of Fruit; (2) Important Insect Pests of Nuts; (3) Field Crop Insect Pests; and (4) Insect Pests of Vegetable Crops. The first publication gives the hosts, injury, and description of 22 insect…

  16. Important Insect Pests of Fruit - Important Insect Pests of Nuts - Field Crop Insect Pests - Insect Pests of Vegetable Crops.

    ERIC Educational Resources Information Center

    Gesell, Stanley G.; And Others

    This document consists of four agriculture extension service publications from Pennsylvania State University. The titles are: (1) Important Insect Pests of Fruit; (2) Important Insect Pests of Nuts; (3) Field Crop Insect Pests; and (4) Insect Pests of Vegetable Crops. The first publication gives the hosts, injury, and description of 22 insect…

  17. Insects and other invertebrates

    Treesearch

    John R. Jones; Norbert V. DeByle; Diane M. Bowers

    1985-01-01

    Quaking aspen throughout its range appears to be host to several insect and other invertebrate pests (fig. 1). It is a short-lived species that is palatable to a large variety of animals. Furniss and Carolin (1977) listed 33 insect species that use aspen as a food source. Some are quite damaging and may kill otherwise healthy stands of aspen; others feed on weakened or...

  18. Exploring Insect Vision

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2005-01-01

    A fly is buzzing around in the kitchen. You sneak up on it with a flyswatter, but just as you get close to it, it flies away. What makes flies and other insects so good at escaping from danger? The fact that insects have eyesight that can easily detect moving objects is one of the things that help them survive. In this month's Science Shorts,…

  19. Exploring Insect Vision

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2005-01-01

    A fly is buzzing around in the kitchen. You sneak up on it with a flyswatter, but just as you get close to it, it flies away. What makes flies and other insects so good at escaping from danger? The fact that insects have eyesight that can easily detect moving objects is one of the things that help them survive. In this month's Science Shorts,…

  20. Corazonin in insects.

    PubMed

    Predel, Reinhard; Neupert, Susanne; Russell, William K; Scheibner, Olaf; Nachman, Ronald J

    2007-01-01

    Corazonin is a peptidergic neurohormone of insects that is expressed in neurosecretory neurons of the pars lateralis of the protocerebrum and transported via nervi corporis cardiaci to the storage lobes of the corpora cardiaca. This peptide occurs with a single isoform in all insects studied so far, with the exception of the Coleoptera in which no corazonin form could be detected. Very few modifications of [Arg(7)]-corazonin, originally isolated from cockroaches, are known, namely [His(7)]-corazonin which is expressed in certain locusts and the stick insect Carausius morosus, and [Thr(4), His(7)]-corazonin recently described from the honey bee Apis mellifera. In this study, we performed a comprehensive screening for corazonin in the different insect groups after detecting of a fourth isoform in a crane fly, Tipula sp. ([Gln(10)]-corazonin). [Arg(7)]-corazonin is distributed in most major lineages of insects, and is thus the ancient form which was present at the time the phylum Insecta evolved. The replacement of Arg with His at position 7 from the N-terminus occurred several times in the evolution of insects. The third isoform, [Thr(4), His(7)]-corazonin, seems to be restricted to bees (Apidae); whereas wasps (Vespidae) and a bumble bee (Apidae) express other corazonins, specifically [His(7)]-corazonin and [Tyr(3), Gln(7), Gln(10)]-corazonin, respectively. A novel corazonin form, [His(4), Gln(7)]-corazonin, was also detected in all South African members of the newly described insect order Mantophasmatodea. The [His(4), Gln(7)]-corazonin separates these species from the Namibian Mantophasmatodea which express [Arg(7)]-corazonin and can be used as a distinct character to distinguish these morphologically similar insects.

  1. Olfactory perception, cognition, and dysfunction in humans.

    PubMed

    Stevenson, Richard J

    2013-05-01

    The main functions of olfaction relate to finding food, avoiding predators and disease, and social communication. Its role in detecting food has resulted in a unique dual mode sensory system. Environmental odorants are 'smelled' via the external nostrils, while volatile chemicals in food-detected by the same receptors-arrive via the nasopharynx, contributing to flavor. This arrangement allows the brain to link the consequences of eating with a food's odor, and then later to use this information in the search for food. Recognizing an odorant-a food, mate, or predator-requires the detection of complex chemical blends against a noisy chemical background. The brain solves this problem in two ways. First, by rapid adaptation to background odorants so that new odorants stand out. Second, by pattern matching the neural representation of an odorant to prior olfactory experiences. This account is consistent with olfactory sensory physiology, anatomy, and psychology. Odor perception, and its products, may be subject to further processing-olfactory cognition. While olfactory cognition has features in common with visual or auditory cognition, several aspects are unique, and even those that are common may be instantiated in different ways. These differences can be productively used to evaluate the generality of models of cognition and consciousness. Finally, the olfactory system can breakdown, and this may be predictive of the onset of neurodegenerative conditions such as Alzheimer's, as well as having prognostic value in other disorders such as schizophrenia. WIREs Cogn Sci 2013, 4:273-284. doi: 10.1002/wcs.1224 For further resources related to this article, please visit the WIREs website. Copyright © 2013 John Wiley & Sons, Ltd.

  2. Paced-Mating Increases the Number of Adult New Born Cells in the Internal Cellular (Granular) Layer of the Accessory Olfactory Bulb

    PubMed Central

    Corona, Rebeca; Larriva-Sahd, Jorge; Paredes, Raúl G.

    2011-01-01

    The continuous production and addition of new neurons during life in the olfactory bulb is well accepted and has been extensively studied in rodents. This process could allow the animals to adapt to a changing environment. Olfactory neurogenesis begins in the subventricular zone where stem cells proliferate and give rise to young undifferentiated neuroblasts that migrate along the rostral migratory stream to the olfactory bulb (OB). Olfaction is crucial for the expression of sexual behavior in rodents. In female rats, the ability to control the rate of sexual interactions (pacing) has important physiological and behavioral consequences. In the present experiment we evaluated if pacing behavior modifies the rate of new cells that reach the main and accessory olfactory bulb. The BrdU marker was injected before and after different behavioral tests which included: females placed in a mating cage (control), females allowed to pace the sexual interaction, females that mated but were not able to control the rate of the sexual interaction and females exposed to a sexually active male. Subjects were sacrificed fifteen days after the behavioral test. We observed a significant increase in the density of BrdU positive cells in the internal cellular layer of the accessory olfactory bulb when females paced the sexual interaction in comparison to the other 3 groups. No differences in the cell density in the main olfactory bulb were found. These results suggest that pacing behavior promotes an increase in density of the new cells in the accessory olfactory bulb. PMID:21637743

  3. Insect--plant adaptations.

    PubMed

    Southwood, T R

    1984-01-01

    The adaptation of insects to plants probably commenced in the early Permian period, though most current associations will be more recent. A major burst of adaptation must have followed the rise of the Angiosperms in the Cretaceous period, though some particular associations are as recent as this century. Living plants form a large proportion of the potential food in most habitats, though insects have had to overcome certain general hurdles to live and feed on them. Insects affect the reproduction and survival of plants, and thus the diversity of plant secondary chemicals may have evolved as a response. Where an insect species has a significant effect on a plant species that is its only host, coevolution may be envisaged. A spectacular example is provided by Heliconius butterflies and passion flower vines, studied by L.E. Gilbert and others. But such cases may be likened to 'vortices in the evolutionary stream': most plant species are influenced by a range of phytophagous insects so that selection will be for general defences--a situation termed diffuse coevolution. Evidence is presented on recent host-plant shifts to illustrate both the restrictions and the flexibility in current insect-plant associations.

  4. Insect immunology and hematopoiesis.

    PubMed

    Hillyer, Julián F

    2016-05-01

    Insects combat infection by mounting powerful immune responses that are mediated by hemocytes, the fat body, the midgut, the salivary glands and other tissues. Foreign organisms that have entered the body of an insect are recognized by the immune system when pathogen-associated molecular patterns bind host-derived pattern recognition receptors. This, in turn, activates immune signaling pathways that amplify the immune response, induce the production of factors with antimicrobial activity, and activate effector pathways. Among the immune signaling pathways are the Toll, Imd, Jak/Stat, JNK, and insulin pathways. Activation of these and other pathways leads to pathogen killing via phagocytosis, melanization, cellular encapsulation, nodulation, lysis, RNAi-mediated virus destruction, autophagy and apoptosis. This review details these and other aspects of immunity in insects, and discusses how the immune and circulatory systems have co-adapted to combat infection, how hemocyte replication and differentiation takes place (hematopoiesis), how an infection prepares an insect for a subsequent infection (immune priming), how environmental factors such as temperature and the age of the insect impact the immune response, and how social immunity protects entire groups. Finally, this review highlights some underexplored areas in the field of insect immunobiology.

  5. Neuropeptide F neurons modulate sugar reward during associative olfactory learning of Drosophila larvae.

    PubMed

    Rohwedder, Astrid; Selcho, Mareike; Chassot, Bérénice; Thum, Andreas S

    2015-12-15

    All organisms continuously have to adapt their behavior according to changes in the environment in order to survive. Experience-driven changes in behavior are usually mediated and maintained by modifications in signaling within defined brain circuits. Given the simplicity of the larval brain of Drosophila and its experimental accessibility on the genetic and behavioral level, we analyzed if Drosophila neuropeptide F (dNPF) neurons are involved in classical olfactory conditioning. dNPF is an ortholog of the mammalian neuropeptide Y, a highly conserved neuromodulator that stimulates food-seeking behavior. We provide a comprehensive anatomical analysis of the dNPF neurons on the single-cell level. We demonstrate that artificial activation of dNPF neurons inhibits appetitive olfactory learning by modulating the sugar reward signal during acquisition. No effect is detectable for the retrieval of an established appetitive olfactory memory. The modulatory effect is based on the joint action of three distinct cell types that, if tested on the single-cell level, inhibit and invert the conditioned behavior. Taken together, our work describes anatomically and functionally a new part of the sugar reinforcement signaling pathway for classical olfactory conditioning in Drosophila larvae. © 2015 Wiley Periodicals, Inc.

  6. Odor-evoked gene regulation and visualization in olfactory receptor neurons

    PubMed Central

    Bennett, Mosi K.; Kulaga, Heather M.; Reed, Randall R.

    2010-01-01

    Odorant-evoked activity contributes to olfactory epithelium organization and axon targeting. We examined the consequences on gene expression of a genetic disruption of the channel responsible for olfactory transduction. Genes encoding calcium-binding EF-hand motifs, were among the most highly regulated transcripts consistent with the central role of Ca2+ influx in neuronal depolarization. Several genes encoding integral membrane proteins are also highly regulated. One gene, Lrrc3b, was regulated more than 10-fold by odorant activity. Changes in expression occur within thirty minutes and are maintained for several hours. In genetic disruptions of Lrrc3b, a Lrrc3b-promoter-driven reporter adopts the activity-regulated expression of the endogenous gene. Individual olfactory glomeruli have a wide spectrum of activity levels that can be modulated by altering odor exposure. The Lrrc3b reporter mouse permits direct assessment of activity in identified glomeruli. In stable odorant environments, activity-regulated proteins provide a characteristic signature that is correlated with the olfactory receptor they express. PMID:20080187

  7. Response of the hammerhead shark olfactory epithelium to amino acid stimuli.

    PubMed

    Tricas, Timothy C; Kajiura, Stephen M; Summers, Adam P

    2009-10-01

    Sharks and rays are highly sensitive to chemical stimuli in their natural environment but several hypotheses predict that hammerhead sharks, with their expanded head and enlarged olfactory epithelium, have particularly acute olfactory systems. We used the electro-olfactogram (EOG) technique to compare the relative response of the scalloped hammerhead shark (Sphyrna lewini) olfactory epithelium to 20 proteinogenic amino acids and determine the sensitivity for 6 amino acids. At micromolar concentrations, cysteine evoked the greatest EOG response which was approximately twice as large as that of alanine. The weakest response was obtained for proline followed by aspartic acid and isoleucine. The olfactory epithelium showed adaptation to sequential stimulation, and recovery was related to the inter-stimulus time period. Estimated EOG response thresholds were in the sub-nanomolar range for both alanine (9.2 x 10(-11) M) and cysteine (8.4 x 10(-10) M) and in the micromolar range for proline and serine. These thresholds from 10(-10) to 10(-6) M for the scalloped hammerhead shark are comparable or lower than those reported for other teleost and elasmobranch species. Future work should focus on binary and more complex compounds to test for competition and cross-adaptation for different classes of peripheral receptors, and their responses to molecules found in biologically relevant stimuli.

  8. Lessons from Studying Insect Symbioses

    PubMed Central

    Douglas, Angela E.

    2011-01-01

    As for mammals, insect health is strongly influenced by the composition and activities of resident microorganisms. However, the microbiota of insects is generally less diverse than that of mammals, allowing microbial function in insects to be coupled to individual, identified microbial species. This trait of insect symbioses facilitates our understanding of the mechanisms that promote insect-microbial coexistence and the processes by which the microbiota affect insect wellbeing. As a result, insects are potentially ideal models to study various aspects of interactions between the host and its resident microorganisms that are impractical or unfeasible in mammals and to generate hypotheses for subsequent testing in mammalian models. PMID:22018236

  9. Visual inputs to the mushroom body calyces of the whirligig beetle Dineutus sublineatus: modality switching in an insect.

    PubMed

    Lin, Chan; Strausfeld, Nicholas J

    2012-08-15

    The mushroom bodies are prominent lobed centers in the forebrain, or protocerebrum, of most insects. Previous studies on mushroom bodies have focused on higher olfactory processing, including olfactory-based learning and memory. Anatomical studies provide strong support that in terrestrial insects with mushroom bodies, the primary input region, or calyces, are predominantly supplied by olfactory projection neurons from the antennal lobe glomeruli. In aquatic species that generally lack antennal lobes, the calyces are vestigial or absent. Here we report an exception to this in the whirligig beetle Dineutus sublineatus (Coleoptera: Gyrinidae). This aquatic species lives on water and is equipped with two separate pairs of compound eyes, one pair viewing above and one viewing below the water surface. As in other aquatic insects, the whirligig beetle lacks antennal lobes, but unlike other aquatic insects its mushroom bodies possess robust calyces. Golgi impregnations and fluorescent tracer injections revealed that the calyces are exclusively supplied by visual neurons from the medulla of the dorsal eye optic lobes. No other sensory inputs reach the calyces, thereby showing a complete switch of calyx modality from olfaction to vision. Potential functions of the mushroom bodies of D. sublineatus are discussed in the context of the behavioral ecology of whirligig beetles. Copyright © 2012 Wiley Periodicals, Inc.

  10. Differential combinatorial coding of pheromones in two olfactory subsystems of the honey bee brain.

    PubMed

    Carcaud, Julie; Giurfa, Martin; Sandoz, Jean-Christophe

    2015-03-11

    Neural coding of pheromones has been intensively studied in insects with a particular focus on sex pheromones. These studies favored the view that pheromone compounds are processed within specific antennal lobe glomeruli following a specialized labeled-line system. However, pheromones play crucial roles in an insect's life beyond sexual attraction, and some species use many different pheromones making such a labeled-line organization unrealistic. A combinatorial coding scheme, in which each component activates a set of broadly tuned units, appears more adapted in this case. However, this idea has not been tested thoroughly. We focused here on the honey bee Apis mellifera, a social insect that relies on a wide range of pheromones to ensure colony cohesion. Interestingly, the honey bee olfactory system harbors two central parallel pathways, whose functions remain largely unknown. Using optophysiological recordings of projection neurons, we compared the responses of these two pathways to 27 known honey bee pheromonal compounds emitted by the brood, the workers, and the queen. We show that while queen mandibular pheromone is processed by l-ALT (lateral antennal lobe tract) neurons and brood pheromone is mainly processed by m-ALT (median antennal lobe tract) neurons, worker pheromones induce redundant activity in both pathways. Moreover, all tested pheromonal compounds induce combinatorial activity from several AL glomeruli. These findings support the combinatorial coding scheme and suggest that higher-order brain centers reading out these combinatorial activity patterns may eventually classify olfactory signals according to their biological meaning. Copyright © 2015 the authors 0270-6474/15/354157-11$15.00/0.

  11. Visual and olfactory input segregation in the mushroom body calyces in a basal neopteran, the American cockroach.

    PubMed

    Nishino, Hiroshi; Iwasaki, Masazumi; Yasuyama, Kouji; Hongo, Hidenori; Watanabe, Hidehiro; Mizunami, Makoto

    2012-01-01

    The cockroach Periplaneta americana is an evolutionary basal neopteran insect, equipped with one of the largest and most elaborate mushroom bodies among insects. Using intracellular recording and staining in the protocerebrum, we discovered two new types of neurons that receive direct input from the optic lobe in addition to the neuron previously reported. These neurons have dendritic processes in the optic lobe, projection sites in the optic tracts, and send axonal terminals almost exclusively to the innermost layer of the MB calyces (input site of MB). Their responses were excitatory to visual but inhibitory to olfactory stimuli, and weak excitation occurred in response to mechanosensory stimuli to cerci. In contrast, interneurons with dendrites mainly in the antennal lobe projection sites send axon terminals to the middle to outer layers of the calyces. These were excited by various olfactory stimuli and mechanosensory stimuli to the antenna. These results suggest that there is general modality-specific terminal segregation in the MB calyces and that this is an early event in insect evolution. Possible postsynaptic and presynaptic elements of these neurons are discussed.

  12. 40 CFR 180.1064 - Tomato pinworm insect pheromone; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... RESIDUES IN FOOD Exemptions From Tolerances § 180.1064 Tomato pinworm insect pheromone; exemption from the... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Tomato pinworm insect pheromone... residues of both components of the tomato pinworm insect pheromone (E)-4-tridecen-1-yl acetate and (Z)-4...

  13. 40 CFR 180.1064 - Tomato pinworm insect pheromone; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Tomato pinworm insect pheromone... RESIDUES IN FOOD Exemptions From Tolerances § 180.1064 Tomato pinworm insect pheromone; exemption from the... residues of both components of the tomato pinworm insect pheromone (E)-4-tridecen-1-yl acetate and...

  14. 40 CFR 180.1064 - Tomato pinworm insect pheromone; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Tomato pinworm insect pheromone... RESIDUES IN FOOD Exemptions From Tolerances § 180.1064 Tomato pinworm insect pheromone; exemption from the... residues of both components of the tomato pinworm insect pheromone (E)-4-tridecen-1-yl acetate and...

  15. 40 CFR 180.1064 - Tomato pinworm insect pheromone; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Tomato pinworm insect pheromone... RESIDUES IN FOOD Exemptions From Tolerances § 180.1064 Tomato pinworm insect pheromone; exemption from the... residues of both components of the tomato pinworm insect pheromone (E)-4-tridecen-1-yl acetate and...

  16. Ecological Considerations in Producing and Formulating Fungal Entomopathogens for Use in Insect Biocontrol

    USDA-ARS?s Scientific Manuscript database

    Insect pests persist in a wide variety of agricultural, arboreal, and urban environments. Effective control with fungal entomopathogens using inundation biocontrol requires an understanding of the ecology of the target insect, fungal pathogen, and the insect-pathogen interaction. Historically, the...

  17. Ecological Considerations in Producing and Formulating Fungal Entomopathogens for Use in Insect Biocontrol

    USDA-ARS?s Scientific Manuscript database

    Insect pests persist in a wide-variety of agricultural, arboreal, and urban environments. Effective control with fungal entomopathogens using inundation biocontrol requires an understanding of the ecology of the target insect, fungal pathogen, and the insect-pathogen interaction. Historically, the d...

  18. 40 CFR 180.1064 - Tomato pinworm insect pheromone; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Tomato pinworm insect pheromone... RESIDUES IN FOOD Exemptions From Tolerances § 180.1064 Tomato pinworm insect pheromone; exemption from the... residues of both components of the tomato pinworm insect pheromone (E)-4-tridecen-1-yl acetate and (Z)-4...

  19. Trace amines inhibit insect odorant receptor function through antagonism of the co-receptor subunit

    PubMed Central

    Chen, Sisi; Luetje, Charles W.

    2014-01-01

    Many insect behaviors are driven by olfaction, making insect olfactory receptors (ORs) appealing targets for insect control.  Insect ORs are odorant-gated ion channels, with each receptor thought to be composed of a representative from a large, variable family of odorant binding subunits and a highly conserved co-receptor subunit (Orco), assembled in an unknown stoichiometry.  Synthetic Orco directed agonists and antagonists have recently been identified.  Several Orco antagonists have been shown to act via an allosteric mechanism to inhibit OR activation by odorants.  The high degree of conservation of Orco across insect species results in Orco antagonists having broad activity at ORs from a variety of insect species and suggests that the binding site for Orco ligands may serve as a modulatory site for compounds endogenous to insects or may be a target of exogenous compounds, such as those produced by plants.  To test this idea, we screened a series of biogenic and trace amines, identifying several as Orco antagonists.  Of particular interest were tryptamine, a plant-produced amine, and tyramine, an amine endogenous to the insect nervous system.  Tryptamine was found to be a potent antagonist of Orco, able to block Orco activation by an Orco agonist and to allosterically inhibit activation of ORs by odorants.  Tyramine had effects similar to those of tryptamine, but was less potent.  Importantly, both tryptamine and tyramine displayed broad activity, inhibiting odorant activation of ORs of species from three different insect orders (Diptera, Lepidoptera and Coleoptera), as well as odorant activation of six diverse ORs from a single species (the human malaria vector mosquito, Anopheles gambiae).  Our results suggest that endogenous and exogenous natural compounds serve as Orco ligands modulating insect olfaction and that Orco can be an important target for the development of novel insect repellants. PMID:25075297

  20. The olfactory sense: a developmental and lifespan perspective.

    PubMed

    Wittmann-Price, Ruth A

    2012-09-01

    The objective of this literature review is to discuss human olfactory development, function and assessment through the lifespan. This article will highlight the importance of accurate olfactory function assessment. Olfactory function in humans is an understudied sense and may contribute significantly to patient safety and quality of life. Studies related to olfactory function are presented for different life stages. Olfactory development is reviewed as is terminology used to describe functionality. This article highlights the need for nursing assessment of olfactory function to develop holistic nursing interventions since there are implications for patient safety, quality of life issues related to respiratory function, bonding and nutrition. Literature review. Articles were searched in CINAHL, PsychInfo and PubMed limited to those published in English to 2010 with the key terms 'olfactory and nursing'. The search yielded 47 articles that were clinically based on patient care. Those articles that dealt specifically with traumatic brain syndrome were excluded. However, peer reviewed and research article were both specified. There is evidence that olfactory assessment should be completed by nurses on high risk populations to ensure patent safety and enhance quality of life. More studies are needed to improve clinical knowledge about the role of olfactory function. Nurses are in a prime position to assess olfactory function for patients at high risk for deficits to provide holistic nursing care. © 2012 Blackwell Publishing Ltd.

  1. Gyrodactylus salmonis infection impairs the olfactory system of rainbow trout.

    PubMed

    Lari, E; Pyle, G G

    2017-01-20

    Monogenean worms are ectoparasites that are known to be infectious to a wide variety of fish. Few species of monogenean parasites have been reported in the olfactory chamber of fish in current peer-reviewed literature. However, the impacts of these parasites on the olfactory system are not well understood. In this study, the effects of Gyrodactylus salmonis on the olfactory system structure and performance were investigated in rainbow trout (Oncorhynchus mykiss). The olfactory performance of the infected fish was examined using an electro-olfactography (EOG) technique, while the ultrastructure of the olfactory rosette was studied using scanning electron microscopy (SEM) and light microscopy (LM). The infected rainbow trout displayed reduced responses to two standard olfactory cues (L-alanine and TCA). The SEM micrographs revealed that many regions of the olfactory epithelium in the infected fish were heavily pitted and the LM examination of the olfactory epithelium showed local proliferation of mucous cells in the sensory regions as compared to the control group. The results of this study demonstrated that G. salmonis causes physical damage to the olfactory system of fish that lead to olfactory impairment.

  2. Olfactory Cleft Endoscopy Scale correlates with olfactory metrics in patients with chronic rhinosinusitis

    PubMed Central

    Soler, Zachary M.; Hyer, J. Madison; Karnezis, Tom T.; Schlosser, Rodney J.

    2015-01-01

    Introduction Olfactory loss affects a majority of patients with chronic rhinosinusitis (CRS). Traditional objective measures of disease severity, including endoscopy scales, focus upon the paranasal sinuses and often have weak correlation to olfaction. Methods Adults with CRS were prospectively evaluated by blinded reviewers with a novel Olfactory Cleft Endoscopy Scale (OCES) that evaluated discharge, polyps, edema, crusting and scarring of the olfactory cleft. Objective olfactory function was assessed using “Sniffin’ Sticks testing, including composite threshold-discrimination-identification (TDI) scores. Olfactory-specific quality-of-life was evaluated using the short modified version of the Questionnaire of Olfactory Disorders (QOD-NS). Inter- and intra-rater reliability was assessed among 3 reviewers for OCES grading. Multivariate linear regression was then used to test associations between OCES scores and measures of olfaction, controlling for potential confounding factors. Results The OCES score was evaluated in 38 patients and had a high overall reliability (ICC=0.92; 95% CI: 0.91–0.96). The OCES significantly correlated with objective olfaction as measured by TDI score (p<0.001), with TDI score falling by 1.13 points for every 1 point increase in OCES score. Similar significant associations were found for threshold, discrimination, and identification scores (p<0.003 for all) after controlling for age, gender, race, and reviewer/review. The OCES was also highly associated with patient-reported QOD-NS scores (p=0.009). Conclusion A novel olfactory cleft endoscopy scale shows high reliability and correlates with both objective and patient-reported olfaction in patients with CRS. Further studies to determine prognostic value and responsiveness to change are warranted. PMID:26718315

  3. Local neurons play key roles in the mammalian olfactory bulb.

    PubMed

    Saghatelyan, Armen; Carleton, Alan; Lagier, Samuel; de Chevigny, Antoine; Lledo, Pierre-Marie

    2003-01-01

    Over the past few decades, research exploring how the brain perceives, discriminates, and recognizes odorant molecules has received a growing interest. Today, olfaction is no longer considered a matter of poetry. Chemical senses entered the biological era when an increasing number of scientists started to elucidate the early stages of the olfactory pathway. A combination of genetic, biochemical, cellular, electrophysiological and behavioral methods has provided a picture of how odor information is processed in the olfactory system as it moves from the periphery to higher areas of the brain. Our group is exploring the physiology of the main olfactory bulb, the first processing relay in the mammalian brain. From different electrophysiological approaches, we are attempting to understand the cellular rules that contribute to the synaptic transmission and plasticity at this central relay. How olfactory sensory inputs, originating from the olfactory epithelium located in the nasal cavity, are encoded in the main olfactory bulb remains a crucial question for understanding odor processing. More importantly, the persistence of a high level of neurogenesis continuously supplying the adult olfactory bulb with newborn local neurons provides an attractive model to investigate how basic olfactory functions are maintained when a large proportion of local neurons are continuously renewed. For this purpose, we summarize the current ideas concerning the molecular mechanisms and organizational strategies used by the olfactory system to encode and process information in the main olfactory bulb. We discuss the degree of sensitivity of the bulbar neuronal network activity to the persistence of this high level of neurogenesis that is modulated by sensory experience. Finally, it is worth mentioning that analyzing the molecular mechanisms and organizational strategies used by the olfactory system to transduce, encode, and process odorant information in the olfactory bulb should aid in

  4. Insect bite reactions.

    PubMed

    Singh, Sanjay; Mann, Baldeep Kaur

    2013-01-01

    Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK) disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr) as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some serious adverse effects

  5. An information theoretic model of information processing in the Drosophila olfactory system: the role of inhibitory neurons for system efficiency.

    PubMed

    Faghihi, Faramarz; Kolodziejski, Christoph; Fiala, André; Wörgötter, Florentin; Tetzlaff, Christian

    2013-12-20

    Fruit flies (Drosophila melanogaster) rely on their olfactory system to process environmental information. This information has to be transmitted without system-relevant loss by the olfactory system to deeper brain areas for learning. Here we study the role of several parameters of the fly's olfactory system and the environment and how they influence olfactory information transmission. We have designed an abstract model of the antennal lobe, the mushroom body and the inhibitory circuitry. Mutual information between the olfactory environment, simulated in terms of different odor concentrations, and a sub-population of intrinsic mushroom body neurons (Kenyon cells) was calculated to quantify the efficiency of information transmission. With this method we study, on the one hand, the effect of different connectivity rates between olfactory projection neurons and firing thresholds of Kenyon cells. On the other hand, we analyze the influence of inhibition on mutual information between environment and mushroom body. Our simulations show an expected linear relation between the connectivity rate between the antennal lobe and the mushroom body and firing threshold of the Kenyon cells to obtain maximum mutual information for both low and high odor concentrations. However, contradicting all-day experiences, high odor concentrations cause a drastic, and unrealistic, decrease in mutual information for all connectivity rates compared to low concentration. But when inhibition on the mushroom body is included, mutual information remains at high levels independent of other system parameters. This finding points to a pivotal role of inhibition in fly information processing without which the system efficiency will be substantially reduced.

  6. An information theoretic model of information processing in the Drosophila olfactory system: the role of inhibitory neurons for system efficiency

    PubMed Central

    Faghihi, Faramarz; Kolodziejski, Christoph; Fiala, André; Wörgötter, Florentin; Tetzlaff, Christian

    2013-01-01

    Fruit flies (Drosophila melanogaster) rely on their olfactory system to process environmental information. This information has to be transmitted without system-relevant loss by the olfactory system to deeper brain areas for learning. Here we study the role of several parameters of the fly's olfactory system and the environment and how they influence olfactory information transmission. We have designed an abstract model of the antennal lobe, the mushroom body and the inhibitory circuitry. Mutual information between the olfactory environment, simulated in terms of different odor concentrations, and a sub-population of intrinsic mushroom body neurons (Kenyon cells) was calculated to quantify the efficiency of information transmission. With this method we study, on the one hand, the effect of different connectivity rates between olfactory projection neurons and firing thresholds of Kenyon cells. On the other hand, we analyze the influence of inhibition on mutual information between environment and mushroom body. Our simulations show an expected linear relation between the connectivity rate between the antennal lobe and the mushroom body and firing threshold of the Kenyon cells to obtain maximum mutual information for both low and high odor concentrations. However, contradicting all-day experiences, high odor concentrations cause a drastic, and unrealistic, decrease in mutual information for all connectivity rates compared to low concentration. But when inhibition on the mushroom body is included, mutual information remains at high levels independent of other system parameters. This finding points to a pivotal role of inhibition in fly information processing without which the system efficiency will be substantially reduced. PMID:24391579

  7. 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

  8. Odor detection ability and thallium-201 transport in the olfactory nerve of traumatic olfactory-impaired mice.

    PubMed

    Shiga, Hideaki; Kinoshita, Yayoi; Washiyama, Kohshin; Ogawa, Daisuke; Amano, Ryohei; Hirota, Kyoko; Tsukatani, Toshiaki; Furukawa, Mitsuru; Miwa, Takaki

    2008-09-01

    Although olfactory nerve damage is a contributing factor in the diagnosis of posttraumatic olfactory loss, at present, there are no methods to directly assess injury to these nerves. We have shown that following olfactory nerve injury in mice, thallium-201 (201 Tl) transport from the nasal cavity to the olfactory bulb decreases. To determine if olfactory function after nerve injury could be assessed with nasal administration of 201 Tl, we measured the correlation between odor detection ability (ODA) and the rate of transport of 201 Tl in olfactory nerves. Both ODA and 201 Tl transport were measured after bilateral olfactory nerve transection for a 4-week period. Cycloheximide solution was used for ODA against tap water. 201 Tl transport was measured as the ratio of radioactivity in the nasal cavity and olfactory bulb with gamma spectrometry. There was a significant correlation between ODA and the rate of 201 Tl transport in the olfactory nerve. These findings suggest that olfactory function after nerve injury can be objectively evaluated with the nasal administration of 201 Tl.

  9. Olfactory sensory neurons are trophically dependent on the olfactory bulb for their prolonged survival.

    PubMed

    Schwob, J E; Szumowski, K E; Stasky, A A

    1992-10-01

    In most neural systems, developing neurons are trophically dependent on contact with their synaptic target for their survival and for some features of their differentiation. However, in the olfactory system, it is unclear whether or not the survival and differentiation of olfactory sensory neurons depend on contact with the olfactory bulb (normally the sole synaptic target for these neurons). In order to address this issue, we examined neuronal life-span and differentiation in adult rats subjected to unilateral olfactory bulb ablation at least 1 month prior to use. Life-span of a newly generated cohort of olfactory neurons was determined by labeling them at their "birth" via the incorporation of 3H-thymidine. In the absence of the bulb, neurons are continually produced at a twofold greater rate. However, the epithelium on the ablated side is thinner, indicating that average neuronal life-span must be reduced in the targetless epithelium. Indeed, nearly 90% of the labeled neurons disappear from the bulbectomized side between 5 d and 2 weeks of neuronal age. Moreover, on electron microscopic examination, olfactory axons are degenerating in large numbers on the ablated side. Since labeled neurons migrate apically through the width of the epithelium during this same period, it appears that most, if not all, neurons on the ablated side have a life-span on the order of 2 weeks or less. In contrast, there is a more moderate degree of neuronal loss on the unoperated side of the same animals during the first 2 weeks after tracer injection, and that occurs while the neurons are concentrated in the deeper half of the epithelium, suggesting that there is a preexisting population of neurons in the control epithelium that does not die during this period. Likewise, degenerating axons are much less frequent on the unoperated side. We conclude that life-span is significantly shorter for olfactory neurons born in the targetless epithelium and that olfactory neurons are trophically

  10. Unraveling navigational strategies in migratory insects

    PubMed Central

    Merlin, Christine; Heinze, Stanley; Reppert, Steven M.

    2011-01-01

    Long-distance migration is a strategy some animals use to survive a seasonally changing environment. To reach favorable grounds, migratory animals have evolved sophisticated navigational mechanisms that rely on a map and compasses. In migratory insects, the existence of a map sense (sense of position) remains poorly understood, but recent work has provided new insights into the mechanisms some compasses use for maintaining a constant bearing during long-distance navigation. The best-studied directional strategy relies on a time-compensated sun compass, used by diurnal insects, for which neural circuits have begun to be delineated. Yet, a growing body of evidence suggests that migratory insects may also rely on other compasses that use night sky cues or the Earth's magnetic field. Those mechanisms are ripe for exploration. PMID:22154565

  11. Democratizing evolutionary biology, lessons from insects.

    PubMed

    Dunn, Robert R; Beasley, DeAnna E

    2016-12-01

    The engagement of the public in the scientific process is an old practice. Yet with recent advances in technology, the role of the citizen scientist in studying evolutionary processes has increased. Insects provide ideal models for understanding these evolutionary processes at large scales. This review highlights how insect-based citizen science has led to the expansion of specimen collections and reframed research questions in light of new observations and unexpected discoveries. Given the rapid expansion of human-modified (and inhabited) environments, the degree to which the public can participate in insect-based citizen science will allow us to track and monitor evolutionary trends at a global scale. Copyright © 2016. Published by Elsevier Inc.

  12. Tunicamycin impairs olfactory learning and synaptic plasticity in the olfactory bulb.

    PubMed

    Tong, Jia; Okutani, Fumino; Murata, Yoshihiro; Taniguchi, Mutsuo; Namba, Toshiharu; Wang, Yu-Jie; Kaba, Hideto

    2017-03-06

    Tunicamycin (TM) induces endoplasmic reticulum (ER) stress and inhibits N-glycosylation in cells. ER stress is associated with neuronal death in neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, and most patients complain of the impairment of olfactory recognition. Here we examined the effects of TM on aversive olfactory learning and the underlying synaptic plasticity in the main olfactory bulb (MOB). Behavioral experiments demonstrated that the intrabulbar infusion of TM disabled aversive olfactory learning without affecting short-term memory. Histological analyses revealed that TM infusion upregulated C/EBP homologous protein (CHOP), a marker of ER stress, in the mitral and granule cell layers of MOB. Electrophysiological data indicated that TM inhibited tetanus-induced long-term potentiation (LTP) at the dendrodendritic excitatory synapse from mitral to granule cells. A low dose of TM (250nM) abolished the late phase of LTP, and a high dose (1μM) inhibited the early and late phases of LTP. Further, high-dose, but not low-dose, TM reduced the paired-pulse facilitation ratio, suggesting that the inhibitory effects of TM on LTP are partially mediated through the presynaptic machinery. Thus, our results support the hypothesis that TM-induced ER stress impairs olfactory learning by inhibiting synaptic plasticity via presynaptic and postsynaptic mechanisms in MOB.

  13. Organization of deutocerebral neuropils and olfactory behavior in the centipede Scutigera coleoptrata (Linnaeus, 1758) (Myriapoda: Chilopoda).

    PubMed

    Sombke, Andy; Harzsch, Steffen; Hansson, Bill S

    2011-01-01

    Myriapods represent an arthropod lineage, that originating from a marine arthropod ancestor most likely conquered land independently from hexapods and crustaceans. Establishing aerial olfaction during a transition from the ocean to land requires molecules to be detected in gas phase instead of in water solution. Considering that the olfactory sense of myriapods has evolved independently from that in hexapods and crustaceans, the question arises if and how myriapods have solved the tasks of odor detection and odor information processing in air. Comparative studies between arthropod taxa that independently have established a terrestrial life style provide a powerful means of investigating the evolution of chemosensory adaptations in this environment and to understand how the arthropod nervous system evolved in response to new environmental and ecological challenges. In general, the neuroethology of myriapods and the architecture of their central nervous systems are insufficiently understood. In a set of experiments with the centipede Scutigera coleoptrata, we analyzed the central olfactory pathway with serial semi-thin sectioning combined with 3-dimensional reconstruction, antennal backfilling with neuronal tracers, and immunofluorescence combined with confocal laser-scanning microscopy. Furthermore, we conducted behavioral experiments to find out if these animals react to airborne stimuli. Our results show that the primary olfactory and mechanosensory centers are well developed in these organisms but that the s