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Bruno C L Macena, Fábio H V Hazin
Whale sharks are generally associated with environmental factors that drive their movements to specific locations where food availability is high. Consequently, foraging is believed to be the main reason for the formation of whale shark aggregations. Feeding aggregations occur mainly in nearshore areas and are composed primarily of immature individuals. Conversely, aggregations of mature adults are rarely observed, and their occurrence is correlated with oceanic environments. Despite an increase in the number of whale shark studies, information on mating and parturition grounds is still lacking...
2016: PloS One
M Dunbar, C Onuora, S Morgan, F E Stone, T M Huckaba, I R Davenport
Follicle cell processes (FCP) are identified in two species of carcharhinid shark (Selachii) but are absent in the little skate Leucoraja erinacea (Batoidea). This suggests that FCPs are either a unique structure that evolved in selachians or were lost by the batoids after their divergence, some 280 mya. The presence of FCPs in the selachians would be consistent with the evolution of large oocytes in this group of animals.
October 25, 2016: Journal of Fish Biology
G J Johnson, R C Buckworth, H Lee, J A T Morgan, J R Ovenden, C R McMahon
Multivariate and machine-learning methods were used to develop field identification techniques for two species of cryptic blacktip shark. From 112 specimens, precaudal vertebrae (PCV) counts and molecular analysis identified 95 Australian blacktip sharks Carcharhinus tilstoni and 17 common blacktip sharks Carcharhinus limbatus. Molecular analysis also revealed 27 of the 112 were C. tilstoni × C. limbatus hybrids, of which 23 had C. tilstoni PCV counts and four had C. limbatus PCV counts. In the absence of further information about hybrid phenotypes, hybrids were assigned as either C...
October 24, 2016: Journal of Fish Biology
Steven Taylor
At the age of 56, I am glad I never entered into discussion or read any information about altering or tampering with my NHS pension scheme (news, 21 September, page 10 ). I feel the NHS is acting like a loan shark, encouraging people to stop contributing so they have more money in their pocket today, but this will be paid back four-fold in years to come through lost pension income.
October 12, 2016: Nursing Standard
Andrea J Morash, Sara R C Mackellar, Louise Tunnah, David A Barnett, Kilian M Stehfest, Jayson M Semmens, Suzanne Currie
Estuarine habitats are frequently used as nurseries by elasmobranch species for their protection and abundant resources; however, global climate change is increasing the frequency and severity of environmental challenges in these estuaries that may negatively affect elasmobranch physiology. Hyposmotic events are particularly challenging for marine sharks that osmoconform, and species-specific tolerances are not well known. Therefore, we sought to determine the effects of an acute (48 h) ecologically relevant hyposmotic event (25...
2016: Conservation Physiology
Wen Xu, Xi Ma, Yang Wang
Squalene, a naturally occurring linear triterpene formed via MVA or MEP biosynthetic pathway, is widely distributed in microorganisms, plants and animals. At present, squalene is used extensively in the food, cosmetic and medicine industries because of its antioxidant, antistatic and anti-carcinogenic properties. Increased consumer demand has led to the development of microbial bioprocesses for the commercial production of squalene, in addition to the traditional methods of isolating squalene from the liver oils of deep-sea sharks and plant seed oils...
December 2016: World Journal of Microbiology & Biotechnology
Lian Li, Yan Li, Danyang Feng, Linghua Xu, Fengxin Yin, Hengchang Zang, Chunhui Liu, Fengshan Wang
Chondroitin sulfate (CS) plays important roles in the complement system. However, the CS structure is complicated due to different sources and the number and positions of sulfate groups. The objective of this study was to prepare different low molecular weight chondroitin sulfates (LMWCSs) and to investigate the biological activity in anti-complement capacity. A series of LMWCSs was prepared from different sources and characterized by ultraviolet-visible (UV) spectroscopy, high-performance liquid chromatography (HPLC), size exclusion chromatography-multiangle laser light scattering (SEC-MALLS) and nuclear magnetic resonance (NMR) spectroscopy...
October 11, 2016: International Journal of Molecular Sciences
V Sans-Coma, C Rodríguez, M A López-Unzu, M Lorenzale, B Fernández, L Vida, A C Durán
As far as is known, this paper gives the first description of a two-headed shark embryo belonging to an oviparous species, Galeus atlanticus (Carcharhiniformes: Scyliorhinidae). The specimen was detected among 797 embryos intended for cardiovascular studies, which represents a defect incidence of 0·13%. Each head had a mouth, two eyes, a brain, a notochord and five gill openings on each side. The two heads fused behind the gills. On the single body, there were four anticipated dorsal fins, two anterior, right and left and two posterior, right and left...
October 9, 2016: Journal of Fish Biology
David Costantini, Shona Smith, Shaun S Killen, Julius Nielsen, John F Steffensen
The free radical theory of ageing predicts that long-lived species should be more resistant to oxidative damage than short-lived species. Although many studies support this theory, recent studies found notable exceptions that challenge the generality of this theory. In this study, we have analysed the oxidative status of the Greenland shark (Somniosus microcephalus), which has recently been found as the longest living vertebrate animal known to science with a lifespan of at least 272years. As compared to other species, the Greenland shark had body mass-corrected values of muscle glutathione peroxidase and red blood cells protein carbonyls (metric of protein oxidative damage) above 75 percentile and below 25 percentile, respectively...
October 4, 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
C A J Duffy, M Scott
The occurrence of the sandbar shark Carcharhinus plumbeus at Norfolk Island is confirmed. Carcharhinus plumbeus occurs over the mid to outer insular shelf from 38 m to at least 53 m depth, and appears to be at least as abundant as C. galapagensis in this habitat. No C. plumbeus were caught from shore despite most fishing effort being land-based. The presence of young-of-the-year confirms C. plumbeus breeds on the Norfolk Island shelf. Size at birth and the timing of parturition appear similar to that reported for eastern Australia...
September 26, 2016: Zootaxa
Donald B Smith, Paul Becher, Jens Bukh, Ernest A Gould, Gregor Meyers, Thomas Monath, A Scott Muerhoff, Alexander Pletnev, Rebecca Rico-Hesse, Jack T Stapleton, Peter Simmonds
Proposals are described for the assignment of recently reported viruses, infecting rodents, bats and other mammalian species, to new species within the Hepacivirus and Pegivirus genera (Family Flaviviridae). Assignments into 14 Hepacivirus species (Hepacivirus A to N) and 11 Pegivirus species (Pegivirus A to K) are based on phylogenetic relationships and sequence distances between conserved regions extracted from complete coding sequences of each proposed taxon. We propose that the species hepatitis C virus is renamed Hepacivirus C in order to acknowledge its unique historical position and so as to minimise confusion...
September 28, 2016: Journal of General Virology
Julie Larsen, Peter Bushnell, John Steffensen, Morten Pedersen, Klaus Qvortrup, Richard Brill
We assessed the functional properties in atrial and ventricular myocardium (using isolated cardiac strips) of smooth dogfish (Mustelus canis), clearnose skate (Raja eglanteria), and sandbar shark (Carcharhinus plumbeus) by blocking Ca(2+) release from the sarcoplasmic reticulum (SR) with ryanodine and thapsigargin and measuring the resultant changes in contraction-relaxation parameters and the force-frequency relationship at 20 °C and 30 °C. We also examined ultrastructural differences with electron microscopy...
September 29, 2016: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Danielle E Haulsee, Dewayne A Fox, Matthew W Breece, Lori M Brown, Jeff Kneebone, Gregory B Skomal, Matthew J Oliver
Complex social networks and behaviors are difficult to observe for free-living marine species, especially those that move great distances. Using implanted acoustic transceivers to study the inter- and intraspecific interactions of sand tiger sharks Carcharias taurus, we observed group behavior that has historically been associated with higher order mammals. We found evidence strongly suggestive of fission-fusion behavior, or changes in group size and composition of sand tigers, related to five behavioral modes (summering, south migration, community bottleneck, dispersal, north migration)...
September 30, 2016: Scientific Reports
Kwok Ho Tsoi, Sau Ying Chan, Yeung Chung Lee, Brian Ho Yeung Ip, Chi Chiu Cheang
Shark conservation has become a focus of current international conservation efforts. However, the misunderstanding of sharks and their negative public portrayal may hinder their conservation. More importantly, the consumption of shark fin, which is very common in Chinese cultures, poses a significant threat to sharks. Hong Kong has long been the world's largest shark fin trading center. Shark conservation would become more sustainable if public understanding of this predatory fish and an appreciation of its ecological significance could be promoted...
2016: PloS One
Hon Lun Wong, Aria Ahmed-Cox, Brendan Paul Burns
Microbial mats are unique geobiological ecosystems that form as a result of complex communities of microorganisms interacting with each other and their physical environment. Both the microorganisms present and the network of metabolic interactions govern ecosystem function therein. These systems are often found in a range of extreme environments, and those found in elevated salinity have been particularly well studied. The purpose of this review is to briefly describe the molecular ecology of select model hypersaline mat systems (Guerrero Negro, Shark Bay, S'Avall, and Kiritimati Atoll), and any potentially modulating effects caused by salinity to community structure...
January 5, 2016: Microorganisms
Georgina K Cox, Richard W Brill, Kaitlin A Bonaro, Anthony P Farrell
The coronary circulation first appeared in the chordate lineage in cartilaginous fishes where, as in birds and mammals but unlike most teleost fishes, it supplies arterial blood to the entire myocardium. Despite the pivotal position of elasmobranch fishes in the evolution of the coronary circulation, the determinants of coronary blood flow have never been investigated in this group. Elasmobranch fishes are of special interest because of the morphological arrangement of their cardiomyocytes. Unlike teleosts, the majority of the ventricular myocardium in elasmobranch fishes is distant to the venous blood returning to the heart (i...
September 27, 2016: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
S Uddin, S W Fowler, M Behbehani, M Metian
The tendency of (210)Po to concentrate in body tissue poses a serious concern of radiological safety. This study compiles available information and presents recent (210)Po data for the marine food web in the northern Gulf waters. Since (210)Po is concentrated in marine biota, a large number of samples of various marine organisms covering several trophic levels, from microalgae to sharks, were analyzed. (210)Po was found to be highly concentrated in several marine species with the highest (210)Po concentrations found in yellowfin tuna, i...
September 23, 2016: Journal of Environmental Radioactivity
Ema Romão, Francisco Morales-Yánez, Yaozhong Hu, Maxine Crauwels, Pieter De Pauw, Gholamreza Ghassanzadeh Hassanzadeh, Nick Devoogdt, Chloé Ackaert, Cécile Vincke, Serge Muyldermans
BACKGROUND: The discovery of functional heavy chain-only antibodies devoid of light chains in sera of camelids and sharks in the early nineties provided access to the generation of minimal-sized, single-domain, in vivo affinity-matured, recombinant antigen-binding fragments, also known as Nanobodies. METHODS: Recombinant DNA technology and adaptation of phage display vectors form the basis to construct large naïve, synthetic or medium sized immune libraries from where multiple Nanobodies have been retrieved...
September 23, 2016: Current Pharmaceutical Design
Andrea M Bernard, Kevin A Feldheim, Michael R Heithaus, Sabine P Wintner, Bradley M Wetherbee, Mahmood S Shivji
Knowledge of genetic connectivity dynamics in the world's large-bodied, highly migratory, apex predator sharks across their global ranges is limited. One such species, the tiger shark (Galeocerdo cuvier), occurs worldwide in warm temperate and tropical waters, uses remarkably diverse habitats (nearshore to pelagic) and possesses a generalist diet that can structure marine ecosystems through top-down processes. We investigated the phylogeography and the global population structure of this exploited, phylogenetically enigmatic shark by using 10 nuclear microsatellites (n = 380) and sequences from the mitochondrial control region (CR, n = 340) and cytochrome oxidase I gene (n = 100)...
September 23, 2016: Molecular Ecology
Martin Kirkpatrick, Alice Jollands
No abstract text is available yet for this article.
September 23, 2016: Developmental Medicine and Child Neurology
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