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Olfaction is fundamental in many species of mammals. In rodents, the integrity of this system is required for the expression of parental and sexual behavior, mate recognition, identification of predators, and finding food. Different anatomical and physiological evidence initially indicated the existence of two anatomically distinct chemosensory systems: The main olfactory system (MOS) and the accessory olfactory system (AOS). It was originally conceived that the MOS detected volatile odorants related to food, giving the animal information about the environment. The AOS, on the other hand, detected non-volatile sexually relevant olfactory cues that influence reproductive behaviors and neuroendocrine functions such as intermale aggression, sexual preference, maternal aggression, pregnancy block (Bruce effect), puberty acceleration (Vandenbergh effect), induction of estrous (Whitten effect) and sexual behavior. Over the last decade, several lines of evidence have demonstrated that although these systems could be anatomically separated, there are neuronal areas in which they are interconnected. Moreover, it is now clear that both the MOS and the AOS process both volatile and no-volatile odorants, indicating that they are also functionally interconnected. In the first part of the review, we will describe the behavioral evidence. In the second part, we will summarize data from our laboratory and other research groups demonstrating that sexual behavior in male and female rodents induces the formation of new neurons that reach the main and accessory olfactory bulbs from the subventricular zone. Three factors are essential for the neurons to reach the AOS and the MOS: The stimulation frequency, the stimulus's temporal presentation, and the release of opioids induced by sexual behavior. We propose that the AOS and the MOS are part of a large olfactory system with a high plastic capability, which favors the adaptation of species to different environmental signals.

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Fetuses are able to process olfactory stimuli present in the womb and continue to show a preference for these odors for months after birth. Despite the accumulated knowledge about their early ability to perceive odors, there is a lack of validated scales for odor response in newborns. The evaluation of reactions of the olfactory system to environmental stimuli in infants has been defined by methodological theoretical approaches of experimental and clinical assessment tools. These approaches are mainly based on psychophysical approaches and predominantly use behavioral and physiological measures. Examples can be found in studies describing early abilities of newborn babies for behaviors or heart rate variability showing memory of maternal food preferences or mother's breast milk. This systematic review aimed to determine whether validated odor assessment tools can be feasibly used in studies. Particularly in light of the current COVID-19 pandemic and evidence of associated olfactory impairment resulting from SARS-COV-2 infection, the study is also motivated by the need for tools to assess olfactory function in neonates.

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Lepidoptera are used as a model for the study of insect olfactory proteins. Among them, odorant degrading enzymes (ODEs), that degrade odorant molecules to maintain the sensitivity of antennae, have received less attention. In particular, antennal esterases (AEs; responsible for ester degradation) are crucial for intraspecific communication in Lepidoptera. Currently, transcriptomic and genomic studies have provided AEs in several species. However, efforts in gene annotation, classification, and functional assignment are still lacking. Therefore, we propose to combine evidence at evolutionary, structural, and functional level to update ODEs as well as key information into an easier classification, particularly of AEs. Finally, the kinetic parameters for putative inhibition of ODEs are discussed in terms of its role in future integrated pest management (IPM) strategies.

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SUMMARY: The vomeronasal organ (VNO) is an accessory organ involved on the olfactory pathway, that detects pheromones and emits signals in order to modulate social and reproductive behavior. The VNO stem cells replace neurons throughout life. The aim of this study was to isolate and characterize cells derived from the vomeronasal organ from New Zealand rabbits. Five male rabbits with 120 days were used for cell isolation and culture. Results: VNO-derived cells presented labelling for proliferation (PCNA), undifferentiated profile (Nanog), neuronal (GFAP), mesenchymal stem cells (CD73, CD90 and CD105 and Stro-1). Also, presence of cytoskeletal (Vimentin, b-tubulin and CK-18) and absence of hematopoietic markers (CD34, CD117 and CD45) both by immunofluorescence and flow cytometry. By PCR it was possible to verify the expression of some undifferentiated profile (Oct-4), neuronal (Nestin) and mesenchymal (CD73, CD105 and Vimentin) genes. Functionally, VNO-derived cells differentiate in vitro into adipocytes, osteocytes and chondrocytes, and presented no tumorigenic potential when injected to Balb/c nu/nu mice. In conclusion, the rabbit VNO-derived cells have a profile that could be supportive to VNO olfactory/neuroreceptor epithelium by delivering factors to epithelial turnover or even by differentiation into epithelial cells to replacement of commissural epithelium.

RESUMEN: El órgano vomeronasal (OVN) es un órgano accesorio de la vía olfatoria, que detecta feromonas y emite señales que afectan la modulación del comportamiento social y reproductivo. Las células madre OVN reemplazan las neuronas durante toda la vida. El objetivo de este estudio fue aislar y caracterizar células derivadas del órgano vomeronasal de conejos raza Nueva Zelanda. Para el aislamiento y el cultivo celular se utilizaron cinco conejos machos con una edad de 120 días. Las células del OVN presentaron etiquetado para la proliferación (PCNA), un perfil indiferenciado (Nanog), neuronal (GFAP), células madre mesenquimales (CD73, CD90 y CD105 y Stro-1). Además, se ob- servó presencia de citoesqueleto (Vimentina, β-tubulina y CK-18) y ausencia de marcadores hematopoyéticos (CD34, CD117 y CD45) tanto por inmunofluorescencia como por citometría de flujo. Me- diante PCR fue posible verificar la expresión de algunos genes de perfil indiferenciado (Oct-4), neuronal (Nestin) y mesenquimatoso (CD73, CD105 y Vimentin). Las células derivadas del OVN se diferencian in vitro en adipocitos, osteocitos y condrocitos, y no presentan un potencial tumorigénico al ser infiltrados en ratones Balb / c nu / nu. En conclusión, las células derivadas de OVN de conejo tienen un perfil que podría ser compatible con el epitelio olfatorio / neurorreceptor de OVN transmitiendo factores al recambio epitelial o incluso mediante la diferenciación en células epiteliales para reemplazar el epitelio comisural.

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Odorant-binding proteins (OBPs) are small soluble proteins whose biological function is believed to be facilitating olfaction by assisting the transport of volatile chemicals in both vertebrate and insect sensory organs, where they are secreted. Their capability to interact with a broad range of hydrophobic compounds combined with interesting features such as being small, stable, and easy to produce and modify, makes them suitable targets for applied research in various industrial segments, including textile, cosmetic, pesticide, and pharmaceutical, as well as for military, environmental, health, and security field applications. In addition to reviewing already established biotechnological applications of OBPs, this paper also discusses their potential use in prospecting of new technologies. The development of new products for insect population management is currently the most prevailing use for OBPs, followed by biosensor technology, an area that has recently seen a significant increase in studies evaluating their incorporation into sensing devices. Finally, less typical approaches include applications in anchorage systems and analytical tools. KEY POINTS: • Odorant-binding proteins (OBPs) present desired characteristics for applied research. • OBPs are mainly used for developing new products for insect population control. • Incorporation of OBPs into chemosensory devices is a growing area of study. • Less conventional uses for OBPs include anchorage systems and analytical purposes. Graphical Abstract.

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OBJECTIVE: F-spondin is part of a group of evolutionarily conserved extracellular matrix proteins in vertebrates. It is highly expressed in the embryonic floor plate, and it can bind to the ECM and promote neuronal outgrowth. A characterization of F-spondin expression patterns in the adult zebrafish brain was previously reported by our group. However, given its importance during development, we aimed to obtain a detailed description of green fluorescent protein (GFP) expression driven by the spon1b promotor, in the developing zebrafish brain of the transgenic Tg(spon1b:GFP) line, using light sheet fluorescence microscopy (LSFM). RESULTS: Images obtained in live embryos from 22 to 96 h post fertilization confirmed our earlier reports on the presence of spon1b:GFP expressing cells in the telencephalon and diencephalon (olfactory bulbs, habenula, optic tectum, nuclei of the medial longitudinal fasciculus), and revealed new spon1b:GFP populations in the pituitary anlage, dorso-rostral cluster, and ventro-rostral cluster. LSFM made it possible to follow the dynamics of cellular migration patterns during development. CONCLUSIONS: spon1b:GFP larval expression patterns starts in early development in specific neuronal structures of the developing brain associated with sensory-motor modulation. LSFM evaluation of the transgenic Tg(spon1b:GFP) line provides an effective approach to characterize GFP expression patterns in vivo.

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The European grapevine moth, Lobesia botrana (Denis & Schiffermüller), is a serious pest in vineyards in North and South America. Mating disruption techniques have been used to control and monitor L. botrana on the basis of its sexual communication. This needs a well-tuned olfactory system, in which it is believed that pheromone-binding proteins (PBPs) are key players that transport pheromones in the antennae of moths. In this study, the selectivity of a PBP, named as LbotPBP1, was tested by fluorescence binding assays against 11 sex pheromone components and 6 host plant volatiles. In addition, its binding mechanism was predicted on the basis of structural analyses by molecular docking and complex and steered molecular dynamics (SMD). Our results indicate that LbotPBP1 binds selectively to sex pheromone components over certain host plant volatiles, according to both in vitro and in silico tests. Thus, chain length (14 carbon atoms) and functional groups (i.e., alcohol and ester) appear to be key features for stable binding. Likewise, residues such as Phe12, Phe36, and Phe118 could participate in unspecific binding processes, whilst Ser9, Ser56, and Trp114 could participate in the specific recognition and stabilization of sex pheromones instead of host plant volatiles. Moreover, our SMD approach supported 11-dodecenyl acetate as the best ligand for LbotPBP1. Overall, the dynamics simulations, contact frequency analysis and SMD shed light on the binding mechanism of LbotPBP1 and could overcome the imprecision of molecular docking, supporting the in vitro binding assays. Finally, the role of LbotPBP1 in the chemical ecology of L. botrana is discussed.

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O órgão vomeronasal é um receptor químico capaz de detectar feromônios e por essa razão está envolvido nos comportamentos reprodutivos, sociais e de defesa. A reprodução de pacas tem se destacado na área de comercialização de carne e para fins conservacionistas e de pesquisa, como modelo experimental. Diante da necessidade do detalhamento da morfologia do sistema olfatório secundário, o sistema vomeronasal, foi descrita a anatomia macroscópica, anatomia microscópica e topografia do órgão vomeronasal (OVN) da paca (Cuniculus paca). Foram utilizadas cinco pacas adultas do Setor de Animais Silvestres da FCAV, UNESP, Jaboticabal-SP. Após a eutanásia dos animais, a solução fixadora de formaldeído 10% em tampão fosfato de sódio (PBS) foi perfundida sistemicamente (via aorta ascendente). Mediante dissecação, o OVN foi localizado e individualizado para a descrição topográfica e anatômica. Posteriormente, foi isolado e incluído em parafina plástica. Cortes de cinco micrômetros foram corados com Hematoxilina-Eosina. O OVN encontra-se no assoalho da cavidade nasal em ambos os lados da base do septo nasal e está relacionado com o osso vômer, processos palatinos dos ossos pré-maxilar e maxilar. Rostralmente, comunica-se com a cavidade oral estabelecendo relação com a papila incisiva. É um órgão par com superfície irregular, levemente elíptico em secção transversal, apresentando coloração amarronzada repleta de vasos sanguíneos. À microscopia de luz, notou-se presença da cartilagem vomeronasal. O órgão é revestido por um epitélio não sensorial e neurossensorial.(AU)

The vomeronasal organ is a chemical receptor capable of detecting pheromones and for this reason is involved in reproductive, social and defense behaviors. The breeding of pacas has been highlighted in commercialization of meat and for conservation and research purposes, as an experimental model. Regarding the necessity of detailing the morphology of the secondary olfactory system, the vomeronasal system, the macroscopic anatomy, microscopic anatomy and topography of the vomeronasal organ (OVN) was described. Five adult pacas, from the wild animal Sector at FCAV, Unesp, Jaboticabal, SP were used. After the euthanasia, it was perfused 10% formaldehyde solution by ascendent aorta. The OVN was dissected for topographic and anatomical descriptions. Then, it was included in plastic paraffin. Five micrometres sections were collected and stained with hematoxylin and eosin. The OVN is located on the floor of the nasal cavity in both sides of the base of nasal septum and it was related to the vomer, palatine process of the premaxilar and maxilar bones. In rostral aspect, it has a communication with the oral cavity and with the incisive papilla. It is a paired organ with irregular surface. In transversal section is slight elliptical with brownish colour similar to a sponge full of blood vessels. By light microscopy, it was observed the vomeronasal cartilage. The organ is covered with non-sensorial and neurossensorial epithelia.(AU)

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O órgão vomeronasal é um receptor químico capaz de detectar feromônios e por essa razão está envolvido nos comportamentos reprodutivos, sociais e de defesa. A reprodução de pacas tem se destacado na área de comercialização de carne e para fins conservacionistas e de pesquisa, como modelo experimental. Diante da necessidade do detalhamento da morfologia do sistema olfatório secundário, o sistema vomeronasal, foi descrita a anatomia macroscópica, anatomia microscópica e topografia do órgão vomeronasal (OVN) da paca (Cuniculus paca). Foram utilizadas cinco pacas adultas do Setor de Animais Silvestres da FCAV, UNESP, Jaboticabal-SP. Após a eutanásia dos animais, a solução fixadora de formaldeído 10% em tampão fosfato de sódio (PBS) foi perfundida sistemicamente (via aorta ascendente). Mediante dissecação, o OVN foi localizado e individualizado para a descrição topográfica e anatômica. Posteriormente, foi isolado e incluído em parafina plástica. Cortes de cinco micrômetros foram corados com Hematoxilina-Eosina. O OVN encontra-se no assoalho da cavidade nasal em ambos os lados da base do septo nasal e está relacionado com o osso vômer, processos palatinos dos ossos pré-maxilar e maxilar. Rostralmente, comunica-se com a cavidade oral estabelecendo relação com a papila incisiva. É um órgão par com superfície irregular, levemente elíptico em secção transversal, apresentando coloração amarronzada repleta de vasos sanguíneos. À microscopia de luz, notou-se presença da cartilagem vomeronasal. O órgão é revestido por um epitélio não sensorial e neurossensorial.(AU)

The vomeronasal organ is a chemical receptor capable of detecting pheromones and for this reason is involved in reproductive, social and defense behaviors. The breeding of pacas has been highlighted in commercialization of meat and for conservation and research purposes, as an experimental model. Regarding the necessity of detailing the morphology of the secondary olfactory system, the vomeronasal system, the macroscopic anatomy, microscopic anatomy and topography of the vomeronasal organ (OVN) was described. Five adult pacas, from the wild animal Sector at FCAV, Unesp, Jaboticabal, SP were used. After the euthanasia, it was perfused 10% formaldehyde solution by ascendent aorta. The OVN was dissected for topographic and anatomical descriptions. Then, it was included in plastic paraffin. Five micrometres sections were collected and stained with hematoxylin and eosin. The OVN is located on the floor of the nasal cavity in both sides of the base of nasal septum and it was related to the vomer, palatine process of the premaxilar and maxilar bones. In rostral aspect, it has a communication with the oral cavity and with the incisive papilla. It is a paired organ with irregular surface. In transversal section is slight elliptical with brownish colour similar to a sponge full of blood vessels. By light microscopy, it was observed the vomeronasal cartilage. The organ is covered with non-sensorial and neurossensorial epithelia.(AU)

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Detection of chemical signals from the environment through olfaction is an indispensable mechanism for maintaining an insect's life, evoking critical behavioral responses. Among several proteins involved in the olfactory perception process, the odorant binding protein (OBP) has been shown to be essential for a normally functioning olfactory system. This paper discusses the role of OBPs in insect chemoreception. Here, structural aspects, mechanisms of action and binding affinity of such proteins are reviewed, as well as their promising application as molecular targets for the development of new strategies for insect population management and other technological purposes.

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The olfactory and vomeronasal systems of vertebrates are characterised by neurogenesis occurring throughout life. The regenerative ability of olfactory receptor neurons relies on specific glial cells, the olfactory and vomeronasal axon-surrounding cells. Numerous studies have examined mammalian olfactory ensheathing cells which are considered potential candidates for spinal cord injury repair using cell-based therapy. With regard to non-mammalian vertebrates, limited information is available on these glial cells in fish, and there is no information on them in terrestrial anamniotes, the amphibians. In the present research, we studied the immunocytochemical characteristics of axon-surrounding cells in Ambystoma mexicanum. Urodeles have relatively simple olfactory and vomeronasal systems, and represent a good model for studying ensheathing cells in extant representatives of basal tetrapods. Sections from the decalcified heads of A. mexicanum were immunocytochemically processed for the detection of proteins used in research on mammalian olfactory-ensheathing cells. S100, GFAP and NCAM were clearly observed. p75NTR, Gal-1 and PSA-NCAM showed weak staining. No vimentin immunopositivity was observed. The corresponding areas of the olfactory and vomeronasal pathways displayed the same staining characteristics, with the exception of Gal-1, p75NTR and PSA-NCAM in the mucosae. The degree of marker expression was not uniform throughout the sensory pathways. In contrast to fish, both olfactory and vomeronasal nerves displayed uniform staining intensity. This study showed that some markers for mammalian and fish-ensheathing glia are also applicable in urodeles. The olfactory systems of vertebrates show similarities, and also clear dissimilarities. Further investigations are required to ascertain the functional significance of these regional and interspecific differences.

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