Olfactory Rosette Research Articles

Involvement of Membrane Progestin Receptor Beta (mPRβ/Paqr8) in Sex Pheromone Progestin-Induced Expression of Luteinizing Hormone in the Pituitary of Male Chinese Black Sleeper (Bostrychus Sinensis).

Our previous studies showed that 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) acted as a sex pheromone to induce reproductive success in Chinese black sleeper (Bostrychus sinensis), but its functional mechanism remains unclear. In the present study, we cloned the cDNAs of the gonadotropin subunits (cgα, fshβ, and lhβ), and found that, in exposure to 5 nM DHP, transcript levels of lhβ significantly increased in the pituitary at 6 h post exposure; plasma 11-KT levels increased at 24 h post exposure in mature male fish. In contrast, DHP exposure failed to increase the transcript levels of lhβ in the pituitary of immature male fish, suggesting that the responsiveness to DHP depends on reproductive status. Interestingly, expression of progestin and adipoQ receptor 8 (paqr8, also known as mPRβ) and progesterone receptor membrane component 2 significantly increased in the olfactory rosette of male fish at late meiosis stage following a co-injection of human chorionic gonadotropin (HCG) and luteinizing hormone releasing hormone-A3 (LHRH-A3), while no increases of other progestin receptors were observed. Moreover, Paqr8 protein was localized in the dendritic knobs of the olfactory sensory neurons, which were activated following the in vivo exposure to DHP. The DHP-induced expression of lhβ in pituitary was not inhibited by RU486, an antagonist of nuclear progesterone receptor. Taken together, our results suggested that sex pheromone DHP increased the expression of lhβ transcript in the pituitary and plasma 11-KT levels of mature male, important for reproduction; and Paqr8 might be involved in responding to sex pheromone DHP in the olfactory rosette of male B. sinensis.

Новий тип розвитку нюхової розетки в анциструса звичайного Ancistrus dolichopterus

Залежно від умов існування в риб по-різному розвинені сенсорні системи, а особливо нюховий аналізатор. Здатність риб реагувати на запахи залежить від форми нюхової розетки та морфології нюхових ламел. Уважають, що найкраще розвинений нюховий аналізатор у видів із білатеральною видовженою нюховою розеткою. Зазвичай нюхові розетки зі схожою морфологією характерні для видів із близьких родин або видів, які існують в однакових умовах. Орган нюху риб під час розвитку проходить стадії нюхової плакоди, нюхової ямки та нюхової камери з нюховою розеткою. Проте залишається нез’ясованим механізм розвитку нюхових розеток. Недостатньо уваги звернено на особливості формування центрального шва в нюхових розетках, додавання нових ламел у різних видів костистих риб. Для вивчення розвитку нюхової розетки білатерального типу анциструса звичайного Ancistrus dolichopterus вирощували в лабораторії гістології та морфогенезу Східноєвропейського національного університету імені Лесі Українки. Гістологічні препарати виготовлено за стандартними гістологічними методиками. В анциструса звичайного формування розетки відбувається у чотири етапи. На першому етапі відбувається закладка першої ламели в середній частині нюхової камери та її зростання з ростральною стінкою нюхової камери під час подальшого розвитку. На другому етапі вперше закладаються латеральна й медіальна ламели. На третьому відбувається закладка четвертої ламели з медіального боку від центрального шва. На четвертому етапі проходить спочатку симетрична відносно центрального шва закладка ламел, а потім у парних ламел латеральні ламели залягають ростральніше від медіальних. В Ancistrus dolichopterus центральний шов розвивається з першої центральної ламели, яка зі збільшенням довжини нюхової камери видовжується. Потовщення шва відбувається за рахунок прикріплення до нього нових бічних пар нюхових ламел у ростральній частині нюхової камери. Під час розвитку дистальний кінець центральної ламели зміщується латерально й ламела втрачає осьове положення. Білатеральна нюхова розетка Ancistrus dolichopterus набуває дефінітивного стану внаслідок додавання нових ламел ростральніше від уже розвинутих ламел, як і в більшості костистих риб, навіть з іншими типами нюхових розеток. Під час закладки четвертої ламели простежуємо порушення симетрії й формування ламели в цей період відбувається лише з одного боку від центрального шва. Усі наступні ламели закладаються попарно.

Two new species of Odontostilbe historically hidden under O. microcephala (Characiformes: Cheirodontinae)

ABSTRACT Specimens historically identified as Odontostilbe microcephala from the upper rio Paraná and Andean piedmont tributaries of the río Paraguay are reviewed and split in three species. We found that the distribution of O. microcephala is restricted to the Andean slope of the río Paraguay basin. The species is distinguished from congeners with subterminal mouth by the elongate body, usually 10-12 gill rakers on upper branch and smaller horizontal orbital diameter (24.6-32.8 % HL, mean 28.7%). Specimens from upper rio Paraná constitute two new species, diagnosed from other Cheirodontinae by the presence of mesopterygoid teeth, grouped on median portion and forming a continuous row. The new species are distinguished from each other by having premaxillary teeth with five cusps vs. nine cusps and by the number of lamellae in left and right sides of central median raphe of olfactory rosette with 20-21 vs. 11-12.

Peripheral olfactory structures and maturity-related crypt receptor neuron kinetics in the olfactory epithelium of carp Cyprinus carpio (L.): implications for carnal vulnerability and pest management

Carnal vulnerability is a powerful yet underutilised tool in integrated pest management. The lack of species-specific knowledge of underpinning sexual drivers and mechanisms for their detection has precluded efficient exploitation of the vulnerability. As a step in understanding how mature common carp Cyprinus carpio communicate and attract conspecifics, the present study undertook anatomical and histological examinations of the olfactory system, tracing changes in crypt receptor neurons (CRNs) within the olfactory rosette in relation to gonadal development, as proxy. Quantification of the density and relative position of CRNs in the lamellae revealed that their density increases significantly with sexual maturity in both males and females (P<0.001). In contrast, the CRNs were concentrated in the basal and surface layers of the epithelium (P<0.001) in females and males respectively, suggesting a sex-specific deployment and mobilisation of CRNs with the onset of maturity. This suggests that the mature males are likely equipped to detect and respond to pheromones more rapidly than females, triggering courtship behaviours such as mate pursuit that are generally associated with mature males. This maturity-driven CRN proliferation and mobilisation reveals a susceptibility, particularly of male C. carpio, to carnal lure and capture that could be exploited in pest management programs.

Clarification of the Terminology of the Olfactory Lamellae in Chondrichthyes.

Several papers regard the anatomy of the peripheral olfactory organ, the olfactory rosette, in the class of Chondrichtyes. The complex shape of this organ and the differences among species give clues to functional, evolutionary, and ecological observations; data on a larger number of species are needed in order to have a more complete insight. The rosette is made up of a central support and of numerous lamellae, which are lined by the sensory epithelium. The size, shape and number of these lamellae, which are highly variable among species, are noteworthy because they affect the sensory surface area, the water dynamic within the olfactory chamber, and the organization of the olfactory bulb. In the literature about Chondrichthyes, the definition of olfactory lamella is confused, because authors use the same words for different structures. The average number of lamellae is distinctive for each species, and the meaning of this difference is not completely understood and, in this frame, a not unambiguous definition of lamella leads to difficulties in comparing data from different publications and analyzing them together. We aim to give here an unambiguous definition of olfactory lamella, that should be each single fold of tissue extending from the raphe, and of lamellar number of a given species, that should be the average number of lamellae in one olfactory organ. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:2039-2045, 2017. © 2017 Wiley Periodicals, Inc.

Gross anatomy and histology of the olfactory rosette of the shark Heptranchias perlo

Sharks belonging to the family Hexanchidae have six or seven gill slits, unlike all other elasmobranchs, which have five gill slits. Their olfactory organs have a round shape, which is common for holocephalans, but not for elasmobranchs. Thus, the shape of the olfactory organ represents a further, less striking, peculiarity of this family among elasmobranchs. Despite that, the microscopic anatomy and histology of the olfactory organ have not yet been studied in any species of this family. Here, an anatomical and histological description of the olfactory organ of the sharpnose sevengill shark Heptranchias perlo is given. The organ is a rosette, with a central raphe and 31–34 primary lamellae, which bear secondary lamellae with a more or less branched shape. The elastic connective capsule which envelops the olfactory rosette possibly changes its shape along with water influx. In the olfactory epithelium, the supporting cells also have a secretory function, while no specialized mucous cells are visible; regarding this feature the olfactory epithelium of H. perlo differs from that of other chondrichthyan species. The immunohistochemical investigation of the sensory epithelium shows the absence of immunoreactivity for Gαolf in receptor neurons, which confirms previous observations in Chondrichthyes.

Anatomy of the olfactory bulb in Greenland shark Somniosus microcephalus (Bloch & Schneider, 1801)

Gross morphology and histology of the olfactory rosette of Greenland shark Somniosus microcephalus (Bloch & Schneider, 1801), suggest a well-developed olfactory capability for this top predator and scavenger native to Arctic waters. In the present paper, observations on the olfactory rosette are reported together with the gross morphology and histology of the olfactory bulb whereby the histological analyses revealed some peculiar traits. The olfactory bulb is macroscopically divided into two sub-bulbs and a central undivided part that contain the layers typical of olfactory bulb histology. The two visible sub-bulbs are actually bundles of fila olfactoria. In addition, the olfactory lateral ventricle is peculiarly branched, which may increase the ependymal surface or, alternatively, decrease the distance between the tissues of the olfactory bulb and the ventricle itself. The ependymal surface is known to be a proliferative zone in the olfactory bulb of fishes. In Greenland shark, the olfactory epithelium showed frequent mitosis and apoptosis highlighting the importance of this site in cell renewal. This issue should be pursued further to gain a deeper understanding of the sensory biology of Greenland shark and of elasmobranchs in general.

Gyrodactylus salmonis infection impairs the olfactory system of rainbow trout.

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.

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

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, revealed a statistically significant decrease of about 30% compared to the control. For cOSNs and mOSNs, the decrement in staining intensity may be indicative of cell death, but reduction in antigen expression may not be excluded. In the post-exposure period of 1 month we did not find recovery of mOSNs. We hypothesize that cOSNs are more sensitive than mOSNs to copper treatment, but also more prompted to tissue repair. Anti-TrkA-immunopositive crypt cells appeared not to be affected by copper exposure since statistical analysis excluded any significant difference between the control and treated fish. Comparative studies on OSNs would greatly enhance our understanding of the mechanisms of olfaction.

Histomorphological and microanatomical characteristics of the olfactory organ of freshwater carp, Cirrhinus reba (Hamilton)

Abstract The morphoanatomy, cellular organization, and surface architecture of the olfactory apparatus in Cirrhinus reba (Hamilton) is described using light and scanning electron microscopy. The oval shaped olfactory rosette contained 32 ± 2 primary lamellae on each side of the median raphe, and was lodged on the floor of the olfactory chamber. The olfactory lamellae were basically flat and compactly arranged in the rosette. The olfactory chamber communicated to the outside aquatic environment through inlet and outlet apertures with a conspicuous nasal flap in between. The mid dorsal portion of the olfactory lamellae was characterized by a linguiform process. Sensory and non-sensory regions were distributed separately on each lamella. The sensory epithelium occupied the apical part including the linguiform process, whereas the resting part of the lamella was covered with non-sensory epithelium. The sensory epithelium comprised both ciliated and microvillous receptor cells distinguished by the architecture on their apical part. The non-sensory epithelium possessed mucous cells, labyrinth cells, and stratified epithelial cells with distinctive microridges. The functional importance of the different cells lining the olfactory mucosa was correlated with the ecological habits of the fish examined.

Histological, Topographical and Ultrastructural Organization of Different Cells Lining the Olfactory Epithelium of Red Piranha, Pygocentrus nattereri (Characiformes, Serrasalmidae)

Abstract The structural characterization of the olfactory epithelium in Pygocentrus nattereri Kner, 1858 was studied with the help of light as well as scanning and transmission electron microscope. The oval shaped olfactory rosette consisted of 26–28 primary lamellae radiated from midline raphe. The olfactory epithelium of each lamella was well distributed by sensory and non-sensory epithelium. The sensory epithelium contained morphologically distinct ciliated and microvillous receptor cells, supporting cells and basal cells. The non-sensory epithelium was made up of labyrinth cells, mucous cells and stratified epithelial cells. According to TEM investigation elongated rod emerging out from dendrite end of the receptor cells in the free space. The dendrite process of microvillous receptor cells contained microvilli. The supporting cells had lobular nucleus with clearly seen electron dense nucleolus. The apex of the ciliated non-sensory cells was broad and provided with plenty of kinocilia. Basal cells provided with oval nucleus and contained small number of secretory granules. The mucous cells were restricted to the non-sensory areas and the nuclei situated basally and filled with about two-third of the vesicles. The functional significance of various cells lining the olfactory epithelium was discussed with mode of life and living of fish concerned.

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

Our previous studies suggested that 17α,20β-dihydroxy-4-pregnen-3-one (DHP), an oocyte maturation inducing progestin, also acts as a sex pheromone in Chinese black sleeper Bostrichthys sinensis, a fish species that inhabits intertidal zones and mates and spawns inside a muddy burrow. The electro-olfactogram response to DHP increased during the breeding season. In the present study, we cloned the cDNAs of the nine progestin receptors (pgr, paqr5, 6, 7(a, b), 8, 9, pgrmc1, 2) from B. sinensis, analyzed their tissue distribution, and determined the expression in the olfactory rosette during the reproductive cycle in female and male fish. The deduced amino acid sequences of the nine progestin receptors share high sequence identities with those of other fish species and relatively lower homology with their mammalian counterparts, and phylogenetic analyses classified the nine B. sinensis progestin receptors into their respective progestin receptor groups. Tissue distribution of B. sinensis progestin receptors showed differential expression patterns, but all these nine genes were expressed in the olfactory rosette. Interestingly, paqr5 mRNA was found in the intermediate and basal parts of the olfactory epithelium but not in the central core using in situ hybridization, and its expression level was the highest in the olfactory rosette among the tissues examined. These results suggested Paqr5 may have an important role for transmitting progestin signaling in the olfactory system. The expression levels of paqr7a and paqr7b, pgr and pgrmc2 mRNA peaked around the mid meiotic stage, and that of paqr8 peaked at late meiotic stage in the olfactory rosette in males, while the olfactory expression of paqr5 decreased gradually as spermatogenesis progressed. In contrast, the expression of the progestin receptors did not change significantly during the development of the ovary in the olfactory rosette in females, except that of pgr. Interestingly, the changes of paqr8 expression in the olfactory rosette in males mirrored the changes of plasma DHP levels in females during the reproductive cycle, suggesting the Paqr8 may also be important for deciphering progestin signaling released by female. To our knowledge, this is the first time to demonstrate the presence of all known progestin receptors in a teleost olfactory rosette, and to show different expressions between the males and females during the reproductive cycle. This study provides the first evidence on changes of all purported progestin receptors during a reproductive cycle in teleost olfactory rosette, and suggests that distinct olfactory sensitivities to DHP may be due to the changes and compositions of each progestin receptor in B. sinensis.

Gross morphology and histology of the olfactory organ of the Greenland shark Somniosus microcephalus

The Greenland shark (Somniosus microcephalus) is the largest predatory fish in Arctic waters. Knowledge of the fundamental biology and ecological role of the Greenland shark is limited, and the sensory biology of the Greenland shark has been poorly studied. Given the potential relevant contribution of chemoreception to the sensory capability of the Greenland shark to forage and navigate in low-light environments, we examined the architecture of the peripheral olfactory organ (the olfactory rosette) through morphological, histological and immunohistochemical assays. We found that each olfactory rosette consists of a small number of lamellae (22) associated with a relatively high surface area of the olfactory epithelium. The general organization of the epithelium is similar to that described for other elasmobranchs. However, details that have emerged concerning the cell type composition (absence of crypt neurons, presence of unusually large cells along the olfactory fiber bundles) deserve further investigation. Overall, the structure of the olfactory rosette suggests a well-developed olfactory capability for the Greenland shark coherent with a bentho-pelagic lifestyle.

Scanning electron microscopy of development of the olfactory organ in ontogeny of grass carp Ctenopharyngodon idella

Cytoand morphogenesis of the olfactory organ of grass carp Ctenopharyngodon idella are followed using the method of electron scanning microscopy. Dates of formation of olfactory placode and olfactory pit, olfactory sensory neurons, ciliated nonsensory cells, and other types of cells of olfactory mucosa are determined. In embryos, ciliated olfactory sensory neurons appear, then microvillous olfactory sensory neurons; the ratio of their numbers (approximately 2: 1) is retained throughout the entire fish ontogeny. In embryos, rod-bearing olfactory sensory neurons were found, whose numbers increase and then successively decrease, and they almost completely disappear at the beginning of the fry period. Towards this age, olfactory sensory epithelium is transformed from continuous into discontinuous at the expense of appearance of a large number of sites of ciliated nonsensory epithelium. With formation of olfactory rosette, sensory epithelium covers only lateral surfaces of olfactory lamellae. Numerous ciliated nonsensory cells appear in larvae on the head around the olfactory opening and rapidly disappear in fry with formation of the nasal bridge and entry and exit olfactory nares. The rate of growth of cilia and microvilli of olfactory sensory neurons and kinocilia of ciliated nonsensory cells was determined. In fish of all age groups, the density of distribution of olfactory sensory neurons in the olfactory epithelium is similar and comprises approximately 51000 cells/mm2. The amount of olfactory sensory neurons in the olfactory organ in fish of different age was assessed; in mature fish their number is approximately 40 millions. The relationship between olfactory sensory equipping and development of other structures of the olfactory organ and olfactory sensitivity of fish to odors was traced.

Olfactory Transcriptional Analysis of Salmon Exposed to Mixtures of Chlorpyrifos and Malathion Reveal Novel Molecular Pathways of Neurobehavioral Injury.

Pacific salmon exposed to sublethal concentrations of organophosphate pesticides (OP) have impaired olfactory function that can lead to loss of behaviors that are essential for survival. These exposures often involve mixtures and can occur at levels below those which inhibit acetylcholinesterase (AChE). In this study, juvenile Coho salmon were exposed for 24 h to either 0.1, 0.5, or 2.5 ppb chlorpyrifos (CPF), 2, 10, or 50 ppb malathion (MAL), or binary mixtures of 0.1 CPF:2 ppb MAL, 0.5 CPF:10 ppb MAL, or 2.5 CPF:10 ppb MAL to mimic single and binary environmental exposures. Microarray analysis of olfactory rosettes from pesticide-exposed salmon revealed differentially expressed genes involved in nervous system function and signaling, aryl hydrocarbon receptor signaling, xenobiotic metabolism, and mitochondrial dysfunction. Coho exposed to OP mixtures exhibited a more pronounced loss in detection of a predatory olfactory cue relative to those exposed to single compounds, whereas respirometry experiments demonstrated that exposure to OPs, individually and in mixtures, reduced maximum respiratory capacity of olfactory rosette mitochondria. The observed molecular, biochemical, and behavioral effects occurred largely in the absence of effects on brain AChE. In summary, our results provide new insights associated with the sublethal neurotoxic effects of OP mixtures relevant to environmental exposures involving molecular and cellular pathways of injury to the salmon olfactory system that underlie neurobehavioral injury.

The Olfactory Transcriptome and Progression of Sexual Maturation in Homing Chum Salmon Oncorhynchus keta.

Reproductive homing migration of salmonids requires accurate interaction between the reception of external olfactory cues for navigation to the spawning grounds and the regulation of sexual maturation processes. This study aimed at providing insights into the hypothesized functional link between olfactory sensing of the spawning ground and final sexual maturation. We have therefore assessed the presence and expression levels of olfactory genes by RNA sequencing (RNAseq) of the olfactory rosettes in homing chum salmon Oncorhynchus keta Walbaum from the coastal sea to 75 km upstream the rivers at the pre-spawning ground. The progression of sexual maturation along the brain-pituitary-gonadal axis was assessed through determination of plasma steroid levels by time-resolved fluoroimmunoassays (TR-FIA), pituitary gonadotropin subunit expression and salmon gonadotropin-releasing hormone (sgnrh) expression in the brain by quantitative real-time PCR. RNAseq revealed the expression of 75 known and 27 unknown salmonid olfactory genes of which 13 genes were differentially expressed between fish from the pre-spawning area and from the coastal area, suggesting an important role of these genes in homing. A clear progression towards final maturation was characterised by higher plasma 17α,20β-dihydroxy-4-pregnen-3-one (DHP) levels, increased pituitary luteinizing hormone β subunit (lhβ) expression and sgnrh expression in the post brain, and lower plasma testosterone (T) and 17β-estradiol (E2) levels. Olfactomedins and ependymin are candidates among the differentially expressed genes that may connect olfactory reception to the expression of sgnrh to regulate final maturation.

Differential Gene Expression in Liver, Gill, and Olfactory Rosettes of Coho Salmon (Oncorhynchus kisutch) After Acclimation to Salinity.

Most Pacific salmonids undergo smoltification and transition from freshwater to saltwater, making various adjustments in metabolism, catabolism, osmotic, and ion regulation. The molecular mechanisms underlying this transition are largely unknown. In the present study, we acclimated coho salmon (Oncorhynchus kisutch) to four different salinities and assessed gene expression through microarray analysis of gills, liver, and olfactory rosettes. Gills are involved in osmotic regulation, liver plays a role in energetics, and olfactory rosettes are involved in behavior. Between all salinity treatments, liver had the highest number of differentially expressed genes at 1616, gills had 1074, and olfactory rosettes had 924, using a 1.5-fold cutoff and a false discovery rate of 0.5. Higher responsiveness of liver to metabolic changes after salinity acclimation to provide energy for other osmoregulatory tissues such as the gills may explain the differences in number of differentially expressed genes. Differentially expressed genes were tissue- and salinity-dependent. There were no known genes differentially expressed that were common to all salinity treatments and all tissues. Gene ontology term analysis revealed biological processes, molecular functions, and cellular components that were significantly affected by salinity, a majority of which were tissue-dependent. For liver, oxygen binding and transport terms were highlighted. For gills, muscle, and cytoskeleton-related terms predominated and for olfactory rosettes, immune response-related genes were accentuated. Interaction networks were examined in combination with GO terms and determined similarities between tissues for potential osmosensors, signal transduction cascades, and transcription factors.

Histoarchitectural and surface ultrastructural analysis of the olfactory epithelium of Puntius ticto (Hamilton, 1822)

Organization of various cells lining the olfactory mucosa of Puntius ticto (Hamilton, 1822) were described by light as well as scanning electron microscopy. The paired olfactory chambers located antero-dorsal to the eyes and communicated outside through anterior and posterior nasal openings. The oval shaped olfactory rosette lied at the bottom of chamber and composed of 18-20 lamellae arranged on either side of median raphe. Sensory and non-sensory regions were distributed separately on each lamella. The sensory epithelium consisted mainly of two distinct morphological forms: ciliated and microvillous receptor cells. The non-sensory epithelium contained ciliated non-sensory cells, stratified epithelial cells with concentric microridges and mucous cells. Basal cells were situated at the deeper part of the epithelium, adjacent to the central core. The functional significance of cellular components of the olfactory epithelium was discussed with the habit and habitat of fish.

Dietary sodium protects fish against copper-induced olfactory impairment

Exposure to low concentrations of copper impairs olfaction in fish. To determine the transcriptional changes in the olfactory epithelium induced by copper exposure, wild yellow perch (Perca flavescens) were exposed to 20μg/L of copper for 3 and 24h. A novel yellow perch microarray with 1000 candidate genes was used to measure differential gene transcription in the olfactory epithelium. While three hours of exposure to copper changed the transcription of only one gene, the transcriptions of 70 genes were changed after 24h of exposure to copper. Real-time PCR was utilized to determine the effect of exposure duration on two specific genes of interest, two sub-units of Na/K-ATPase. At 24 and 48h, Na/K-ATPase transcription was down-regulated by copper at olfactory rosettes. As copper-induced impairment of Na/K-ATPase activity in gills can be ameliorated by increased dietary sodium, rainbow trout (Oncorhynchus mykiss) were used to determine if elevated dietary sodium was also protective against copper-induced olfactory impairment. Measurement of the olfactory response of rainbow trout using electro-olfactography demonstrated that sodium was protective of copper-induced olfactory dysfunction. This work demonstrates that the transcriptions of both subunits of Na/K-ATPase in the olfactory epithelium of fish are affected by Cu exposure, and that dietary Na protects against Cu-induced olfactory dysfunction.

The peripheral olfactory organ in the Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801)

Event Abstract Back to Event The peripheral olfactory organ in the Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801) Sara Ferrando1, Lorenzo Gallus1, Laura Ghigliotti2, Marino Vacchi2, Julius Nielsen3, Jorgen S. Christiansen4 and Eva Pisano1* 1 University of Genova, Department of Earth, Environment and Life Science (DISTAV), Italy 2 CNR ISMAR GE, Italy 3 Københavns Universitet, Marinbiologisk Sektion, Denmark 4 Uit The Arctic University of Norway, Norway The Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801) is the largest predatory fish in Arctic waters. The socio-economic significance of Greenland shark is demonstrated by its impact on the fishing cultures in Greenland, Scandinavia and Iceland for centuries. The fundamental biology and ecological role of Greenland shark, on the other hand, is virtually unknown. Although knowledge of its life history is limited, increasing evidence indicates that the Greenland shark may undertake long-distance migrations and perform vertical movements from the surface to the deep sea. It is an omnivorous species feeding on carrion and a wide variety of pelagic and bottom-dwelling organisms ranging from invertebrates to mammals, and including active species such as fishes and seals. Accordingly, Greenland shark should be recognized as a top predator, with a strong potential to influence the trophic dynamics of the Arctic marine ecosystem. The sensory biology of Greenland shark is scarcely studied, and considering the importance of olfaction in chemoreception, feeding and other behavioral traits, we examined the architecture of the peripheral olfactory organ where olfactory cues are received from the environment – the olfactory rosette. The structural organization of the olfactory rosette, in terms of histological features of the sensory epithelium, number of primary lamellae and total sensory surface area, provides a first proxy of the olfactory capability of Greenland shark. Based on own results and published studies, the overall morphology of the olfactory rosette is viewed in context of the functional and trophic ecology among other elasmobranch species. Acknowledgements Research supported by the PNRA (Italian Programme for Antarctic Research, Project 2013/AZ.1.11) and TUNU-Programme lead by the UiT The Arctic University of Norway Keywords: Greenland shark, Somniosus microcephalus, Olfactory rosette, Arctic Regions, Arctic fish, Arctic biodiversity Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Poster Presentation Topic: Physiology, Behavior and Toxicology Citation: Ferrando S, Gallus L, Ghigliotti L, Vacchi M, Nielsen J, Christiansen JS and Pisano E (2015). The peripheral olfactory organ in the Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801). Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00072 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 12 Nov 2015; Published Online: 12 Nov 2015. * Correspondence: Prof. Eva Pisano, University of Genova, Department of Earth, Environment and Life Science (DISTAV), Genoa, Italy, pisano@unige.it Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sara Ferrando Lorenzo Gallus Laura Ghigliotti Marino Vacchi Julius Nielsen Jorgen S Christiansen Eva Pisano Google Sara Ferrando Lorenzo Gallus Laura Ghigliotti Marino Vacchi Julius Nielsen Jorgen S Christiansen Eva Pisano Google Scholar Sara Ferrando Lorenzo Gallus Laura Ghigliotti Marino Vacchi Julius Nielsen Jorgen S Christiansen Eva Pisano PubMed Sara Ferrando Lorenzo Gallus Laura Ghigliotti Marino Vacchi Julius Nielsen Jorgen S Christiansen Eva Pisano Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.