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https://www.readbyqxmd.com/read/28306752/structural-characterization-of-fluoride-species-in-shark-teeth
#1
Hsun-Hui Chang, Ming-Jou Chien, Chun-Chieh Kao, Yu-Jo Chao, Pao-Tao Yu, Chun-Yu Chang, Shing-Jong Huang, Yuan-Ling Lee, Jerry C C Chan
In shark teeth we have identified the species fluorapatite, hydroxyfluorapatite and its defect site, calcium fluoride, and potassium fluoride. Their relative amounts in teeth at different development stages have been quantified. Calcium fluoride and potassium fluoride may be associated with the fluoridation mechanism in shark teeth.
March 17, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28303139/evolution-of-interferons-and-interferon-receptors
#2
REVIEW
Chris J Secombes, Jun Zou
The earliest jawed vertebrates (Gnathostomes) would likely have had interferon (IFN) genes, since they are present in extant cartilaginous fish (sharks and rays) and bony fish (lobe-finned and ray-finned fish, the latter consisting of the chondrostei, holostei, and teleostei), as well as in tetrapods. They are thought to have evolved from a class II helical cytokine ancestor, along with the interleukin (IL)-10 cytokine family. The two rounds of whole genome duplication (WGD) that occurred between invertebrates and vertebrates (1) may have given rise to additional loci, initially containing an IL-10 ancestor and IFN ancestor, which have duplicated further to give rise to the two loci containing the IL-10 family genes, and potentially the IFN type I and IFN type III loci (2)...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28302412/mechanical-behavior-of-idealized-stingray-skeleton-inspired-tiled-composites-as-a-function-of-geometry-and-material-properties
#3
A K Jayasankar, R Seidel, J Naumann, L Guiducci, A Hosny, P Fratzl, J C Weaver, J W C Dunlop, M N Dean
Tilings are constructs of repeated shapes covering a surface, common in both manmade and natural structures, but in particular are a defining characteristic of shark and ray skeletons. In these fishes, cartilaginous skeletal elements are wrapped in a surface tessellation, comprised of polygonal mineralized tiles linked by flexible joints, an arrangement believed to provide both stiffness and flexibility. The aim of this research is to use two-dimensional analytical models to evaluate the mechanical performance of stingray skeleton-inspired tessellations, as a function of their material and structural parameters...
February 28, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28298593/learning-and-robustness-to-catch-and-release-fishing-in-a-shark-social-network
#4
Johann Mourier, Culum Brown, Serge Planes
Individuals can play different roles in maintaining connectivity and social cohesion in animal populations and thereby influence population robustness to perturbations. We performed a social network analysis in a reef shark population to assess the vulnerability of the global network to node removal under different scenarios. We found that the network was generally robust to the removal of nodes with high centrality. The network appeared also highly robust to experimental fishing. Individual shark catchability decreased as a function of experience, as revealed by comparing capture frequency and site presence...
March 2017: Biology Letters
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
#5
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/28286223/historical-introgression-drives-pervasive-mitochondrial-admixture-between-two-species-of-pelagic-sharks
#6
Shannon Corrigan, Pierpaolo Maisano Delser, Corey Eddy, Clinton Duffy, Lei Yang, Chenhong Li, Adam L Bazinet, Stefano Mona, Gavin J P Naylor
We use a genomic sampling of both nuclear and mitochondrial DNA markers to examine a pattern of genetic admixture between Carcharhinus galapagensis (Galapagos sharks) and Carcharhinus obscurus, (dusky sharks), two well-known and closely related sharks that have been recognized as valid species for more than 100 years. We describe widespread mitochondrial-nuclear discordance in which these species are readily distinguishable based on 2152 nuclear single nucleotide polymorphisms from 910 independent autosomal regions, but show pervasive mitochondrial admixture...
March 9, 2017: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/28282621/uranium-238-u-induced-ros-and-cell-cycle-perturbations-antioxidant-responses-and-erythrocyte-nuclear-abnormalities-in-the-freshwater-iridescent-shark-fish-pangasius-sutchi
#7
Sathesh Kumar Annamalai, Kantha Deivi Arunachalam
The strategic plan of this study is to analyze any possible radiological impact on aquatic organisms from forthcoming uranium mining facilities around the Nagarjuna Sagar Dam in the future. The predominantly consumed and dominant fish species Pangasius sutchi, which is available year-round at Nagarjuna Sagar Dam, was selected for the study. To comprehend the outcome and to understand the mode of action of (238)U, the fish species Pangasius sutchi was exposed to ¼ and ½ of the LC50 doses of waterborne (238)U in a static system in duplicate for 21 days...
March 2, 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28282415/dynamics-of-marsh-mangrove-ecotone-since-the-mid-holocene-a-palynological-study-of-mangrove-encroachment-and-sea-level-rise-in-the-shark-river-estuary-florida
#8
Qiang Yao, Kam-Biu Liu
Sea level rise and the associated inland shift of the marsh-mangrove ecotone in south Florida have raised many scientific and management concerns in recent years. Holocene paleoecological records can provide an important baseline to shed light on the long-term dynamics of vegetation changes across this ecotone in the past, which is needed to predict the future. In this study, we present palynological, X-ray fluorescence, and loss-on ignition data from four sedimentary cores recovered from a 20-km marine-to-freshwater transect along the Shark River Estuary, southwest Everglades, to document the patterns and processes of coastal vegetation changes in response to sea level rise since the mid-Holocene...
2017: PloS One
https://www.readbyqxmd.com/read/28277961/discrimination-factors-and-incorporation-rates-for-organic-matrix-in-shark-teeth-based-on-a-captive-feeding-study
#9
S S Zeichner, A S Colman, P L Koch, C Polo-Silva, F Galván-Magaña, S L Kim
Sharks migrate annually over large distances and occupy a wide variety of habitats, complicating analysis of lifestyle and diet. A biogeochemical technique often used to reconstruct shark diet and environment preferences is stable isotope analysis, which is minimally invasive and integrates through time and space. There are previous studies that focus on isotopic analysis of shark soft tissues, but there are limited applications to shark teeth. However, shark teeth offer an advantage of multiple ecological snapshots and minimum invasiveness during removal because of their distinct conveyor belt tooth replacement system...
March 2017: Physiological and Biochemical Zoology: PBZ
https://www.readbyqxmd.com/read/28274762/are-whale-sharks-exposed-to-persistent-organic-pollutants-and-plastic-pollution-in-the-gulf-of-california-mexico-first-ecotoxicological-investigation-using-skin-biopsies
#10
Maria Cristina Fossi, Matteo Baini, Cristina Panti, Matteo Galli, Begoña Jiménez, Juan Muñoz-Arnanz, Letizia Marsili, Maria Grazia Finoia, Dení Ramírez-Macías
The whale shark (Rhincodon typus) is an endangered species that may be exposed to micro- and macro-plastic ingestion as a result of their filter-feeding activity, particularly on the sea surface. In this pilot project we perform the first ecotoxicological investigation on whale sharks sampled in the Gulf of California exploring the potential interaction of this species with plastic debris (macro-, micro-plastics and related sorbed contaminants). Due to the difficulty in obtaining stranded specimens of this endangered species, an indirect approach, by skin biopsies was used for the evaluation of the whale shark ecotoxicological status...
March 5, 2017: Comparative Biochemistry and Physiology. Toxicology & Pharmacology: CBP
https://www.readbyqxmd.com/read/28271570/single-domain-antibodies-for-the-knockdown-of-cytosolic-and-nuclear-proteins
#11
REVIEW
Thomas Böldicke
Single domain antibodies (sdAbs) from camels or sharks comprise only the variable heavy chain domain. Human sdAbs comprise the variable domain of the heavy chain (VH) or light chain (VL) and can be selected from human antibodies. SdAbs are stable, non aggregating molecules in vitro and in vivo compared to complete antibodies and scFv fragments. They are excellent novel inhibitors of cytosolic/nuclear proteins because they are correctly folded inside the cytosol in contrast to scFv fragments. SdAbs are unique because of their excellent specificity and possibility to target posttranslational modifications such as phosphorylation sites, conformers or interaction regions of proteins that cannot be targeted with genetic knockout techniques and are impossible to knockdown with RNAi...
March 8, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28268804/acoustic-emission-and-angular-movement-variations-from-early-adulthood-healthy-knees-to-late-adulthood-osteoarthritic-knees
#12
Lik-Kwan Shark, Hongzhi Chen, Wei Quan, John Goodacre
From sit-stand-sit movements performed by healthy and osteoarthritic knees in three different age bands, this paper presents the investigation of the relationship between joint angular movement measured using electro-goniometers and acoustic emission measured using piezoelectric sensors. By partitioning joint movement in each sit-stand-sit cycle into sub-movement phases based on ascending and descending as well as acceleration and deceleration, the statistical analysis reveals aged and osteoarthritic knees exhibiting increased asymmetry and more variable angular movement compared with young and age-matched healthy knees, particularly in the descending-deceleration phase...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268047/gross-anatomy-and-histology-of-the-olfactory-rosette-of-the-shark-heptranchias-perlo
#13
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
#14
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
#15
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
https://www.readbyqxmd.com/read/28261458/species-identification-and-comparative-population-genetics-of-four-coastal-houndsharks-based-on-novel-ngs-mined-microsatellites
#16
Simo N Maduna, Charné Rossouw, Charlene da Silva, Michelle Soekoe, Aletta E Bester-van der Merwe
The common smooth-hound (Mustelus mustelus) is the topmost bio-economically and recreationally important shark species in southern Africa, western Africa, and Mediterranean Sea. Here, we used the Illumina HiSeq™ 2000 next-generation sequencing (NGS) technology to develop novel microsatellite markers for Mustelus mustelus. Two microsatellite multiplex panels were constructed from 11 polymorphic loci and characterized in two populations of Mustelus mustelus representative of its South African distribution. The markers were then tested for cross-species utility in Galeorhinus galeus, Mustelus palumbes, and Triakis megalopterus, three other demersal coastal sharks also subjected to recreational and/or commercial fishery pressures in South Africa...
March 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28248805/clinical-features-of-27-shark-attack-cases-on-la-r%C3%A3-union-island
#17
Richard Ballas, Ghislain Saetta, Charline Peuchot, Philippe Elkienbaum, Emmanuelle Poinsot
BACKGROUND: Between January 2000 and September 2016, there have been 27 documented shark attacks on La Réunion Island. The insular nature of La Réunion has allowed us to carry out an extensive survey of these attacks. The objective was to describe the clinical features of these shark attacks, as only case reports have been published up to now. METHODS: This was a retrospective observational study of the 27 cases of non-provoked shark attacks that have occurred between January 2000 and September 2016...
February 28, 2017: Journal of Trauma and Acute Care Surgery
https://www.readbyqxmd.com/read/28247014/electrophysiological-measures-of-temporal-resolution-contrast-sensitivity-and-spatial-resolving-power-in-sharks
#18
Laura A Ryan, Jan M Hemmi, Shaun P Collin, Nathan S Hart
In most animals, vision plays an important role in detecting prey, predators and conspecifics. The effectiveness of vision in assessing cues such as motion and shape is influenced by the ability of the visual system to detect changes in contrast in both space and time. Understanding the role vision plays in shark behaviour has been limited by a lack of knowledge about their temporal resolution, contrast sensitivity and spatial resolution. In this study, an electrophysiological approach was used to compare these measures across five species of sharks: Chiloscyllium punctatum, Heterodontus portusjacksoni, Hemiscyllium ocellatum, Mustelus mustelus and Haploblepharus edwardsii...
February 28, 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/28241029/squamation-and-ecology-of-thelodonts
#19
Humberto G Ferrón, Héctor Botella
Thelodonts are an enigmatic group of Paleozoic jawless vertebrates that have been well studied from taxonomical, biostratigraphic and paleogeographic points of view, although our knowledge of their ecology and mode of life is still scant. Their bodies were covered by micrometric scales whose morphology, histology and the developmental process are extremely similar to those of extant sharks. Based on these similarities and on the well-recognized relationship between squamation and ecology in sharks, here we explore the ecological diversity and lifestyles of thelodonts...
2017: PloS One
https://www.readbyqxmd.com/read/28239865/effect-of-weight-and-frontal-area-of-external-telemetry-packages-on-the-kinematics-activity-levels-and-swimming-performance-of-small-bodied-sharks
#20
I A Bouyoucos, C D Suski, J W Mandelman, E J Brooks
This study sought to observe the effects of submerged weight and frontal cross-sectional area of external telemetry packages on the kinematics, activity levels and swimming performance of small-bodied juvenile sharks, using lemon sharks Negaprion brevirostris (60-80 cm total length, LT ) as a model species. Juveniles were observed free-swimming in a mesocosm untagged and with small and large external accelerometer packages that increased frontal cross-sectional area of the animals and their submerged weight...
February 27, 2017: Journal of Fish Biology
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