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Elasmobranch

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https://www.readbyqxmd.com/read/28616238/validation-of-a-portable-waterproof-blood-ph-analyser-for-elasmobranchs
#1
Brendan Talwar, Ian A Bouyoucos, Oliver Shipley, Jodie L Rummer, John W Mandelman, Edward J Brooks, R Dean Grubbs
Quantifying changes in blood chemistry in elasmobranchs can provide insights into the physiological insults caused by anthropogenic stress, and can ultimately inform conservation and management strategies. Current methods for analysing elasmobranch blood chemistry in the field are often costly and logistically challenging. We compared blood pH values measured using a portable, waterproof pH meter (Hanna Instruments HI 99161) with blood pH values measured by an i-STAT system (CG4+ cartridges), which was previously validated for teleost and elasmobranch fishes, to gauge the accuracy of the pH meter in determining whole blood pH for the Cuban dogfish (Squalus cubensis) and lemon shark (Negaprion brevirostris)...
2017: Conservation Physiology
https://www.readbyqxmd.com/read/28609989/freshwater-fishes-of-northern-australia
#2
Bradley J Pusey, Damien W Burrows, Mark J Kennard, Colton N Perna, Peter J Unmack, Quentin Allsop, Michael P Hammer
Northern Australia is biologically diverse and of national and global conservation signicance. Its ancient landscape contains the world's largest area of savannah ecosystem in good ecological condition and its rivers are largely free-flowing. Agriculture, previously confined largely to open range-land grazing, is set to expand in extent and to focus much more on irrigated cropping and horticulture. Demands on the water resources of the region are thus, inevitably increasing. Reliable information is required to guide and inform development and help plan for a sustainable future for the region which includes healthy rivers that contain diverse fish assemblages...
April 11, 2017: Zootaxa
https://www.readbyqxmd.com/read/28594833/diet-and-trophic-ecology-of-the-tiger-shark-galeocerdo-cuvier-from-south-african-waters
#3
Matthew L Dicken, Nigel E Hussey, Heather M Christiansen, Malcolm J Smale, Nomfundo Nkabi, Geremy Cliff, Sabine P Wintner
Knowledge of the diet and trophic ecology of apex predators is key for the implementation of effective ecosystem as well as species-based management initiatives. Using a combination of stomach content data and stable isotope analysis (δ15N and δ13C) the current study provides information on size-based and sex-specific variations in diet, trophic position (TP) and foraging habitat of tiger sharks (Galeocerdo cuvier) caught in the KwaZulu-Natal Sharks Board bather protection program. This study presents the longest time-series and most detailed analysis of stomach content data for G...
2017: PloS One
https://www.readbyqxmd.com/read/28593636/biosynthesis-of-1%C3%AE-hydroxycorticosterone-in-the-winter-skate-leucoraja-ocellata-evidence-to-suggest-a-novel-steroidogenic-route
#4
J Wiens, R Ho, A K Brassinga, C A Deck, P J Walsh, R N Ben, K Mcclymont, T Charlton, A N Evans, W G Anderson
The present study explores the ability of intracellular bacteria within the renal-inter-renal tissue of the winter skate Leucoraja ocellata to metabolize steroids and contribute to the synthesis of the novel elasmobranch corticosteroid, 1α-hydroxycorticosterone (1α-OH-B). Despite the rarity of C1 hydroxylation noted in the original identification of 1α-OH-B, literature provides evidence for steroid C1 hydroxylation by micro-organisms. Eight ureolytic bacterial isolates were identified in the renal-inter-renal tissue of L...
June 7, 2017: Journal of Fish Biology
https://www.readbyqxmd.com/read/28579535/distributional-shift-of-urea-production-site-from-the-extraembryonic-yolk-sac-membrane-to-the-embryonic-liver-during-the-development-of-cloudy-catshark-scyliorhinus-torazame
#5
Wataru Takagi, Makiko Kajimura, Hironori Tanaka, Kumi Hasegawa, Shuntaro Ogawa, Susumu Hyodo
Urea is an essential osmolyte for marine cartilaginous fishes. Adult elasmobranchs and holocephalans are known to actively produce urea in the liver, muscle and other extrahepatic organs; however, osmoregulatory mechanisms in the developing cartilaginous fish embryo with an undeveloped urea-producing organ are poorly understood. We recently described the contribution of extraembryonic yolk sac membranes (YSM) to embryonic urea synthesis during the early developmental period of the oviparous holocephalan elephant fish (Callorhinchus milii)...
June 1, 2017: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
https://www.readbyqxmd.com/read/28572998/mobulid-rays-feed-on-euphausiids-in-the-bohol-sea
#6
Christoph A Rohner, Katherine B Burgess, Joshua M Rambahiniarison, Joshua D Stewart, Alessandro Ponzo, Anthony J Richardson
Mobulid rays have a conservative life history and are caught in direct fisheries and as by-catch. Their subsequent vulnerability to overexploitation has recently been recognized, but fisheries management can be ineffective if it ignores habitat and prey preferences and other trophic interactions of the target species. Here, we assessed the feeding ecology of four mobulids (Manta birostris, Mobula tarapacana, M. japanica, M. thurstoni) in the Bohol Sea, Philippines, using stomach contents analysis of fisheries specimens landed between November and May in 2013-2015...
May 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28543786/immunohistochemical-colocalization-of-g-protein-alpha-subunits-and-5-ht-in-the-rectal-gland-of-the-cartilaginous-fish-scyliorhinus-canicula
#7
E R Lauriano, S Pergolizzi, J Gangemi, M Kuciel, G Capillo, M Aragona, C Faggio
Serotonin [5-hydroxytryptamine (5-HT)] is an important neuromodulator involved in a wide range of physiological functions. The effects of serotonin are mediated by an extended family of receptors coupled to multiple heterotrimeric G-proteins, associated with cellular membrane. G proteins connect receptors to effectors and thus trigger intracellular signaling pathways. These cellular processes several regulate systemic functions such as embryonic development, gonadal development, learning and memory, and organismal homeostasis...
May 22, 2017: Microscopy Research and Technique
https://www.readbyqxmd.com/read/28529682/segmentations-of-the-cartilaginous-skeletons-of-chondrichthyan-fishes-by-the-use-of-state-of-the-art-computed-tomography
#8
Andrew D McQuiston, Callie Crawford, U Joseph Schoepf, Akos Varga-Szemes, Christian Canstein, Matthias Renker, Carlo N De Cecco, Stefan Baumann, Gavin J P Naylor
AIM: To apply dual-source multidetector computed tomography (DSCT) scanning technology in conjunction with computationally assisted segmentation in order to explore and document skeletal variation that has occurred over the course of evolution. METHODS: We examined 4 divergent species of elasmobranchs with high-resolution 3(rd) generation DSCT. The formalin prepared species examined were: Aptychotrema vincentiana, Mitsukurina owstoni, Negaprion brevirostris and Dactylobatus armatus...
April 28, 2017: World Journal of Radiology
https://www.readbyqxmd.com/read/28484261/variability-in-multiple-paternity-rates-for-grey-reef-sharks-carcharhinus-amblyrhynchos-and-scalloped-hammerheads-sphyrna-lewini
#9
M E Green, S A Appleyard, W White, S Tracey, J Ovenden
This study assessed the presence and prevalence of multiple paternity (MP) in litters of grey reef sharks (Carcharhinus amblyrhynchos) and scalloped hammerheads (Sphyrna lewini) opportunistically caught in Papua New Guinea (PNG). Litter size between species were significantly different with an average of 3.3 pups for grey reef sharks and 17.2 pups for scalloped hammerhead. Using 14 and 10 microsatellite loci respectively, we identified MP in 66% of grey reef sharks (4 out of 6 litters) and 100% MP in scalloped hammerheads (5 litters)...
May 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28469835/developing-an-ancient-epithelial-appendage-fgf-signalling-regulates-early-tail-denticle-formation-in-sharks
#10
Rory L Cooper, Kyle J Martin, Liam J Rasch, Gareth J Fraser
BACKGROUND: Vertebrate epithelial appendages constitute a diverse group of organs that includes integumentary structures such as reptilian scales, avian feathers and mammalian hair. Recent studies have provided new evidence for the homology of integumentary organ development throughout amniotes, despite their disparate final morphologies. These structures develop from conserved molecular signalling centres, known as epithelial placodes. It is not yet certain whether this homology extends beyond the integumentary organs of amniotes, as there is a lack of knowledge regarding their development in basal vertebrates...
2017: EvoDevo
https://www.readbyqxmd.com/read/28444441/the-activity-of-the-rectal-gland-of-the-north-pacific-spiny-dogfish-squalus-suckleyi-is-glucose-dependent-and-stimulated-by-glucagon-like-peptide-1
#11
Courtney A Deck, W Gary Anderson, J Michael Conlon, Patrick J Walsh
Elasmobranchs possess a specialised organ, the rectal gland, which is responsible for excreting sodium chloride via the posterior intestine. Previous work has indicated that the gland may be activated by a number of hormones, some of which are likely related to the salt or volume loads associated with feeding. Furthermore, evidence exists for the gland being glucose dependent which is atypical for an elasmobranch tissue. In this study, the presence of sodium-glucose co-transporters (SGLTs) in the rectal gland and their regulation by feeding were investigated...
April 25, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28426406/infection-of-the-lesser-spotted-dogfish-with-proleptus-obtusus-dujardin-1845-nematoda-spirurida-reflects-ontogenetic-feeding-behaviour-and-seasonal-differences-in-prey-availability
#12
Carlota Silva, Ana Veríssimo, Pedro Cardoso, Jo Cable, Raquel Xavier
Proleptus obtusus Dujardin, 1845 is the most common parasite infecting the gut of the lesser spotted dogfish (Scyliorhinus canicula, Linnaeus). This nematode is trophically transmitted from an intermediate crustacean host to the definitive elasmobranch host. Sexual and age-related differences in habitat occupancy and feeding behaviour of the lesser spotted dogfish make this parasite-host dyad ideal for testing which aspects of host biology influence parasite transmission. Here, the relationship between P. obtusus burden and host condition, sex and age were investigated in lesser spotted dogfish captured in the Northeast Atlantic...
June 1, 2017: Acta Parasitologica
https://www.readbyqxmd.com/read/28350489/redescription-and-molecular-assessment-of-relationships-among-three-species-of-echeneibothrium-rhinebothriidea-echeneibothriidae-parasitizing-the-yellownose-skate-dipturus-chilensis-in-chile
#13
Veronica M Bueno, Janine N Caira
Much progress has recently been made in revising the taxonomic assignments of genera originally classified in the polyphyletic "Tetraphyllidea." Many of these genera, including Echeneibothrium, were accommodated in the order Rhinebothriidea. However, beyond this larger taxonomic action, little work has been conducted on this genus over the past 50 yr. Consequently, the criteria used for characterizing species of Echeneibothrium have lagged behind those typically used in more modern descriptions of elasmobranch-hosted cestode taxa...
June 2017: Journal of Parasitology
https://www.readbyqxmd.com/read/28343270/magnetic-field-discrimination-learning-and-memory-in-the-yellow-stingray-urobatis-jamaicensis
#14
Kyle C Newton, Stephen M Kajiura
Elasmobranch fishes (sharks, skates, and rays) have been hypothesized to use the geomagnetic field as a cue for orienting and navigating across a wide range of spatial scales. Magnetoreception has been demonstrated in many invertebrate and vertebrate taxa, including elasmobranchs, but this sensory modality and the cognitive abilities of cartilaginous fishes are poorly studied. Wild caught yellow stingrays, Urobatis jamaicensis (N = 8), underwent conditioning to associate a magnetic stimulus with a food reward in order to elicit foraging behaviors...
July 2017: Animal Cognition
https://www.readbyqxmd.com/read/28331385/annotated-checklist-of-fish-cestodes-from-south-america
#15
Philippe V Alves, Alain de Chambrier, Tomáš Scholz, José L Luque
An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (Cestoda) that, as adults or larvae (metacestodes), parasitize freshwater, brackish water and marine fishes, i.e. cartilaginous and bony fishes, in South America. The current knowledge of their species diversity, host associations and geographical distribution is reviewed. Taxonomic problems are discussed based on a critical evaluation of the literature and information on DNA sequences of individual taxa is provided to facilitate future taxonomic and phylogenetic studies...
2017: ZooKeys
https://www.readbyqxmd.com/read/28324166/redescription-of-chloromyxum-ellipticum-li-nie-1973-myxosporea-chloromyxidae-infecting-the-gall-bladder-of-grass-carp-ctenopharyngodon-idellus-valenciennes-1844-supplemented-by-morphological-and-molecular-characteristics
#16
J Y Zhang, Y L Zhao, M D Batueva, D Luo, Z F Xing, Q Q Zhang, X H Liu
The traditional taxonomy of the genus Chloromyxum Mingazzini, 1890 has been intensively challenged to be paraphyletic by recent ribosomal DNA (rDNA)-based phylogenetic analysis. Undersampling to get rich sequence data to infer more scientific phylogenetic relationships makes scientists conservatively assign all non-marine elasmobranch-infecting species as Chloromyxum sensu lato. Although complex ridge pattern on the spore surface observed by scanning electron microscopy was thought to be critical for the identification of Chloromyxum species, insufficient data also prevent this ultrastructural data to be a valid taxonomic feature for this genus...
March 21, 2017: Parasitology Research
https://www.readbyqxmd.com/read/28286227/ultrastructural-material-and-crystallographic-description-of-endophytic-masses-a-possible-damage-response-in-shark-and-ray-tessellated-calcified-cartilage
#17
Ronald Seidel, Michael Blumer, Paul Zaslansky, David Knötel, Daniel R Huber, James C Weaver, Peter Fratzl, Sidney Omelon, Luca Bertinetti, Mason N Dean
The cartilaginous endoskeletons of elasmobranchs (sharks and rays) are reinforced superficially by minute, mineralized tiles, called tesserae. Unlike the bony skeletons of other vertebrates, elasmobranch skeletons have limited healing capability and their tissues' mechanisms for avoiding damage or managing it when it does occur are largely unknown. Here we describe an aberrant type of mineralized elasmobranch skeletal tissue called endophytic masses (EPMs), which grow into the uncalcified cartilage of the skeleton, but exhibit a strikingly different morphology compared to tesserae and other elasmobranch calcified tissues...
March 9, 2017: Journal of Structural Biology
https://www.readbyqxmd.com/read/28268047/gross-anatomy-and-histology-of-the-olfactory-rosette-of-the-shark-heptranchias-perlo
#18
Sara Ferrando, Lorenzo Gallus, Andrea Amaroli, Chiara Gambardella, Baradi Waryani, Davide Di Blasi, Marino Vacchi
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...
February 17, 2017: Zoology: Analysis of Complex Systems, ZACS
https://www.readbyqxmd.com/read/28264196/molecular-basis-of-ancestral-vertebrate-electroreception
#19
Nicholas W Bellono, Duncan B Leitch, David Julius
Elasmobranch fishes, including sharks, rays, and skates, use specialized electrosensory organs called ampullae of Lorenzini to detect extremely small changes in environmental electric fields. Electrosensory cells within these ampullae can discriminate and respond to minute changes in environmental voltage gradients through an unknown mechanism. Here we show that the voltage-gated calcium channel CaV1.3 and the big conductance calcium-activated potassium (BK) channel are preferentially expressed by electrosensory cells in little skate (Leucoraja erinacea) and functionally couple to mediate electrosensory cell membrane voltage oscillations, which are important for the detection of specific, weak electrical signals...
March 16, 2017: Nature
https://www.readbyqxmd.com/read/28262360/an-evaluation-of-mercury-offloading-in-two-central-california-elasmobranchs
#20
Kelley E van Hees, David A Ebert
Elasmobranchs occupy high trophic levels, accumulate high concentrations of mercury in their tissues, and have high energetic levels of maternal investment to offspring, which may cause embryos to be exposed in utero to harmful concentrations of mercury. We investigated the maternal transfer of mercury in two common coastal elasmobranch species, Triakis semifasciata and Platyrhinoidis triseriata, to determine which reproductive parameters may influence mercury offloading, and whether embryos are at risk to mercury toxicity...
March 2, 2017: Science of the Total Environment
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