The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Eric R. Lacy - One of the best experts on this subject based on the ideXlab platform.
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Identification of a Glycosylated Relaxin-like Molecule from the Male Atlantic Stingray, Dasyatis sabina†
Biochemistry, 1997Co-Authors: Erika E. Büllesbach, Christian Schwabe, Eric R. LacyAbstract:The alkaline gland fluid of the Atlantic stingray (Dasyatis sabina) contains a molecule that cross-reacts weakly to anti-porcine relaxin antibodies. This material was isolated and purified to homog...
Yuichi Sasayama - One of the best experts on this subject based on the ideXlab platform.
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Corpuscles of Stannius-extract-induced rapid but transient hypocalcemia and hyperphosphatemia in stingray, Dasyatis akajei.
General and comparative endocrinology, 1996Co-Authors: Ajai K. Srivastav, Yuichi Sasayama, Sunil Kumar Srivastav, Nobuo SuzukiAbstract:Abstract Aqueous extracts of goldfish Corpuscles of Stannius were tested in an elasmobranch, Dasyatis akajei, to investigate the effects upon plasma calcium and inorganic phosphate. The extract produced hypocalcemia and hyperphosphatemia in the stingray. Receptors with affinity for stanniocalcin are therefore widespread among the vertebrates.
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Calcitonin of the stingray: Comparison of the hypocalcemic activity with other calcitonins
General and Comparative Endocrinology, 1992Co-Authors: Yuichi Sasayama, Takushi X Watanabe, Kiichiro Nakajima, Yoshio Takei, Nobuo Suzuki, Chitaru Oguro, Akiyoshi Takahashi, Shumpei SakakibaraAbstract:Abstract Hypocalcemic potency of calcitonin isolated from the stingray (cartilaginous fish), Dasyatis akajei , was examined using the rat bioassay and compared with the activities of other calcitonins (human, pig, salmon, eel, and fowl). The potency of Dasyatis calcitonin (dCT) was estimated to be 1500–3800 IU/mg. However, when the duration of the hypocalcemic effect of dCT was taken into consideration, it was judged that dCT was approximately 2.4–6.2 times more potent than mammalian calcitonins, but about 2.3–3.5 times less active than other nonmammalian calcitonins.
Armando T. Wakida-kusunoki - One of the best experts on this subject based on the ideXlab platform.
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First record of total albinism in southern stingray Dasyatis americana
Revista de biología marina y oceanografía, 2015Co-Authors: Armando T. Wakida-kusunokiAbstract:This paper describes the first record of total albinism in the southern stingray Dasyatis americana. The disc width of the albino sub adult female specimen was 640 mm and the total weight was 9,850 g. It was captured in the coast of Tabasco, southeastern Mexico.
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First record of total albinism in southern stingray Dasyatis americana Primer reporte de albinismo total en la raya Dasyatis americana
2015Co-Authors: Armando T. Wakida-kusunokiAbstract:This paper describes the first record of total albinism in the southern stingray Dasyatis americana. The disc width of the albino sub adult female specimen was 640 mm and the total weight was 9,850 g. It was captured in the coast of Tabasco, southeastern Mexico.
Nobuo Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Corpuscles of Stannius-extract-induced rapid but transient hypocalcemia and hyperphosphatemia in stingray, Dasyatis akajei.
General and comparative endocrinology, 1996Co-Authors: Ajai K. Srivastav, Yuichi Sasayama, Sunil Kumar Srivastav, Nobuo SuzukiAbstract:Abstract Aqueous extracts of goldfish Corpuscles of Stannius were tested in an elasmobranch, Dasyatis akajei, to investigate the effects upon plasma calcium and inorganic phosphate. The extract produced hypocalcemia and hyperphosphatemia in the stingray. Receptors with affinity for stanniocalcin are therefore widespread among the vertebrates.
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Calcitonin of the stingray: Comparison of the hypocalcemic activity with other calcitonins
General and Comparative Endocrinology, 1992Co-Authors: Yuichi Sasayama, Takushi X Watanabe, Kiichiro Nakajima, Yoshio Takei, Nobuo Suzuki, Chitaru Oguro, Akiyoshi Takahashi, Shumpei SakakibaraAbstract:Abstract Hypocalcemic potency of calcitonin isolated from the stingray (cartilaginous fish), Dasyatis akajei , was examined using the rat bioassay and compared with the activities of other calcitonins (human, pig, salmon, eel, and fowl). The potency of Dasyatis calcitonin (dCT) was estimated to be 1500–3800 IU/mg. However, when the duration of the hypocalcemic effect of dCT was taken into consideration, it was judged that dCT was approximately 2.4–6.2 times more potent than mammalian calcitonins, but about 2.3–3.5 times less active than other nonmammalian calcitonins.
Paul D. Cowley - One of the best experts on this subject based on the ideXlab platform.
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Dietary niche differentiation in a mesopredatory dasyatid assemblage
Marine Biology, 2020Co-Authors: Chantel Elston, Paul D. Cowley, Rainer G. Von Brandis, Aaron FiskAbstract:Most batoids are mesopredators and are often hypothesised to play important ecological roles. However, a comprehensive understanding into these roles remains limited given the paucity of information of their trophic habits. St. Joseph Atoll ( $$5.43^{\circ }\hbox { S}$$ 5 . 43 ∘ S , $$53.35^{\circ }\hbox { E}$$ 53 . 35 ∘ E ) is a remote ecosystem that hosts a resident assemblage of dasyatids ( Pastinachus ater , Urogymnus granulatus , and U. asperrimus ). Both stomach contents (SC) and stable isotope samples (SI) ( $$\delta ^{15}\hbox {N}$$ δ 15 N and $$\delta ^{13}\hbox {C}$$ δ 13 C ) were collected in 2015 and used to investigate the trophic niches of this dasyatid assemblage and whether these niches differed inter- and intra-specifically. Dasyatid muscle samples as well as baseline samples of potential prey species and primary producers were collected for SI analyses. SC data highlighted significant inter-specific differences in diet, U. granulatus juveniles mostly consumed decapod crustaceans (Callianassidae and Portunidae) and P. ater juveniles mostly consumed bivalve molluscs. The mean species trophic positions for juveniles of all three species ranged from 2.9 to 3.6 when calculated using $$\delta ^{15}\hbox {N}$$ δ 15 N and from 3.4 to 3.6 when calculated using stomach content data. Analysis of $$\delta ^{13}\hbox {C}$$ δ 13 C showed that all juveniles were reliant upon the same carbon resources (primarily derived from seagrass beds) at the base of the food web. Diet appeared to change with size as larger individuals displayed lower $$\delta ^{13}\hbox {C}$$ δ 13 C and higher $$\delta ^{15}\hbox {N}$$ δ 15 N compared to smaller juveniles. Additionally, isotope values of the smallest individuals were similar to the largest individuals, suggesting maternal meddling. The identified patterns of inter- and intra-specific trophic niche differentiation may be indicative of competitive effects and contributes to the understanding of mesopredators in community trophic dynamics.
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Reproduction and embryonic development of the blue stingray, Dasyatis chrysonota , in southern African waters
Journal of the Marine Biological Association of the United Kingdom, 2008Co-Authors: David A. Ebert, Paul D. CowleyAbstract:Dasyatis chrysonota is perhaps the most common of the 14 whiptail stingray (Chondrichthyes: Dasyatidae) species known to frequent the temperate coastal waters of southern Africa and like other stingrays they possess life history characteristics that make them vulnerable to over-exploitation. First and 50% maturity ( D w 50 ) were determined for 153 males and 204 females from the Eastern Cape Province of South Africa. Disc width ( D w ) for first and D w 50 maturity was estimated at 392 mm and 395 mm D w , respectively for males and at 500 mm and 505 mm D w , respectively for females. The reproductive cycle of males, based on gonadosomatic (GSI) and hepatosomoatic (HSI) indices indicates that they are most active during the spring. Females appear to have an annual reproductive cycle with a maximum HSI occurring during the summer and autumn, but it declines steadily through the birthing season reaching a low in the late spring. Fecundity, following a nine month gestation period, averages 2.8 with a range of 1–7. Embryos at six different development stages are described. Dasyatis chrysonota , like other dasyatids, exhibit life history characteristics that make them vulnerable to overexploitation, therefore a precautionary management strategy is advised for this species.
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A taxonomic re-evaluation of the blue stingray from southern Africa (Myliobatiformes: Dasyatidae)
South African Journal of Marine Science, 1993Co-Authors: Paul D. Cowley, Leonard J. V. CompagnoAbstract:The taxonomic status of the southern African stingray usually referred to Dasyatis pastinaca was investigated. Morphological comparisons were made between specimens of the European Dasyatis pastinaca (Linnaeus 1758), Dasyatis marmorata (Steindachner 1892) from Senegal (Senegambia), and the blue stingray from South Africa and Namibia. The earliest name for blue stingrays is the generally overlooked Trigon chrysonotus Smith, 1828 from South Africa, which is revived, redescribed and has a neotype designated for it. The southern African blue stingray is a separate species from D. pastinaca and differs in coloration, disc length and vertebral and radial counts. However, the southern African blue stingray is considered conspecific with D. marmorata but differs slightly in snout angle and snout-to-vent length. These two are tentatively ranked as subspecies, Dasyatis chrysonota chrysonota (Smith 1828) for the blue stingray of South Africa, Namibia and Angola and D. c. marmorata (Steindachner 1892) for the Senegal...
