Disease relevance of Elasmobranchii

• The purpose of this study was to determine if an HKalpha1 orthologue exists in an elasmobranch (Atlantic stingray, Dasyatis sabina), to determine if it is expressed in gills and, if so, to localize its expression and determine if its expression is regulated during hypercapnia or freshwater acclimation [1].

High impact information on Elasmobranchii

• Previously, we have shown that multiple germline genes and mammalian-like recombination signal sequences are associated with the VH gene family of Heterodontus francisci (horned shark), a primitive elasmobranch [2].
• ANG II stimulates the SNS in agnathans, elasmobranchs, teleosts, amphibians, reptiles, birds and mammals [3].
• Granulated juxtaglomerular cells similar to the renin-containing cells of the mammalian nephron are found in most extant vertebrate species although not in agnathan and elasmobranch fish [3].
• Elasmobranch fishes, the coelacanth, estivating lungfish, amphibians, and mammals synthesize urea by the ornithine-urea cycle; by comparison, urea synthetic activity is generally insignificant in teleostean fishes [4].
• Toadfish synthesize urea using enzymes and subcellular distributions similar to those of elasmobranchs: glutamine-dependent carbamoyl phosphate synthethase (CPS III) and mitochondrial arginase [4].

Biological context of Elasmobranchii

• In general, marine elasmobranch fishes (sharks, skates, and rays) maintain body fluid osmolality above seawater, principally by retaining large amounts of urea [5].
• The longest P. motoro StAR transcript contains a sequence with great similarity to short interspersed repetitive elements found in other elasmobranchs [6].
• However, CNP is the only NP identified in the heart and brain of elasmobranchs, suggesting that it is the ancestral type of the NP family and that ANP, BNP and VNP appeared later in the vertebrate phylogeny [7].
• Both isoforms of elasmobranch MBP contain 18.5% basic (lysine plus arginine) amino acids, compared with 17.5% in mammalian MBPs comprised of the corresponding exons [8].
• Among elasmobranchs, variation in the evolutionary rates of the nuclear rRNA genes was higher than that of cytochrome b genes, mainly due to the relatively rapid evolution of rRNA in some carcharhiniforms [9].

Anatomical context of Elasmobranchii

• Here we describe a transmembrane glycoprotein (Mr approximately 100,000) that is present in secretory vesicles in all neurons and endocrine cells studied, in species from elasmobranch fish to mammals, and in neural and endocrine cell lines [10].
• Intact synaptic vesicles prepared from the electric organ of the marine elasmobranch Narcine brasiliensis have eight major polypeptides demonstrable on sodium dodecyl sulfate gels [11].
• High levels of both glutamine synthetase and a unique L-glutamine- and N-acetyl-L-glutamate-dependent carbamoyl phosphate synthetase are present in the mitochondria in livers of marine urea-retaining elasmobranchs (Casey, C. A., and Anderson, P. M. (1982) J. Biol. Chem. 257, 8449-8453) [12].
• Proteoglycan (PG)-1000 (formerly TAP-1) is a large (Mr = 10(6)) highly glycosylated chondroitin sulfate proteoglycan found associated with Schwann cell and electrocyte basement membranes in elasmobranch electric fish [13].
• We have purified cholinergic synaptic vesicles from the electric organs of two related marine elasmobranchs, Torpedo californica and Narcine brasiliensis, to a specific activity higher than had previously been obtained [14].

Associations of Elasmobranchii with chemical compounds

• Glutamine- and N-acetylglutamate-dependent carbamoyl phosphate synthetase in elasmobranchs [15].
• This histidine is invariant in all amniotic CA isozymes sequenced to date, as well as the CAs from elasmobranch and algal sources and in a viral CA-related protein [16].
• Effect of albumin binding on extraction of sulfobromophthalein by perfused elasmobranch liver: evidence for dissociation-limited uptake [17].
• Glutamine synthetase and arginase are mitochondrial enzymes in uricotelic species, but are normally found in the cytoplasm in ureotelic species. the properties of the elasmobranch arginase, however, are characteristic of arginases from ureotelic species (e.g. the Km for arginine is 1.2 mM, and the enzyme has an Mr congruent to 100,000) [18].
• Identification of a facilitated UT in the kidney of the Atlantic stingray provides further support for the proposal that passive mechanisms contribute to urea reabsorption by elasmobranch kidney [5].

Gene context of Elasmobranchii

• The distribution of DRP is conserved across a large evolutionary distance, from mammals to elasmobranchs, suggesting that DRP may play a role in the maintenance of regional specializations in the brain [19].
• Comparative vascular responses in elasmobranchs to different structures of neuropeptide Y and peptide YY [20].
• Here we isolate and characterize CXCR genes from a range of elasmobranch species [21].
• The polyclonal antibody R6, which was raised against porcine relaxin, reacts with a wide variety of naturally occurring relaxins from primates, marine and terrestrial mammals, and elasmobranchs but does not recognize insulin [22].
• From an evolutionary point of view, the appearance of BGP seems to parallel the appearance of hydroxyapatite-containing bone structures since it has never been found in elasmobranchs, whose skeleton is composed of calcified cartilage [23].

Analytical, diagnostic and therapeutic context of Elasmobranchii

• Measurement of 1alpha-hydroxycorticosterone and other corticosteroids in elasmobranch plasma by radioimmunoassay [24].
• The effects of arginine vasotocin on the pattern of glomerular perfusion in an elasmobranch fish were examined using an in situ perfused renal trunk preparation [25].
• Natural concentrations of lithium in blood plasma and urine of several species of elasmobranchs and teleosts from the Black Sea and in rectal gland fluid of the former were determined by mass-spectrometric isotope dilution techniques [26].
• The localization of PTHrP by immunohistochemistry and in situ hybridization revealed conserved sites of distribution from elasmobranchs to mammals, including skin, kidney, muscle and skeleton [27].

References