Elasmobranchs

Comparative Studies of Lorenzini Jelly from Two Species of Elasmobranch. Part II. Structural Studies of Glycopeptides," M. J. How, J. V. S. Jones, and M. Stacey, Carbohydr. Res., 12 (1970) 171-181. 

Yancey, R.N. Somero, G.N. (1979). Counteraction of urea destabilization of protein structure by methylamine osmoregulatory compounds of elasmobranch fishes. BiochemicalJournal, 183, 317-23. 

Dryer L. and Graziadei P. (1993). A pilot study on morphological compart-mentalization and heterogeneity in the elasmobranch olfactory bulb. Anat Embryol (Berl) 188, 41-51. 

Zeiske E.B., Theisen B. and Breuckner H. (1989). Olfactory organs in pelagic and benthic elasmobranchs. Zool Fortsch 35, 370-372. 

Maximum concentrations of copper in elasmobranchs and teleosts from all collection sites range from 7 to 15 mg/kg DW in eyeballs, intestines, muscle, scales, vertebrae, heart, and gonads and from 16 to 48 mg/kg DW in gills, kidneys, skin, and spleens. They reach 53 mg/kg DW in whole animals, 155 mg/kg DW in stomach contents, 208 mg/kg DW in feces, and 245 mg/kg DW in livers (Table 3.3). 

Marine vertebrates, including fishes and elasmobranchs, have low zinc concentrations in tissues (i.e., 6 to 400 mg/kg DW) when compared to marine plants and invertebrates (Eisler 1980, 1981, 1984). Highest concentrations in muscle of marine fishes (20.1 to 25.0 mg/kg FW) were recorded in northern anchovy (Engraulis mordax) and Atlantic menhaden (Brevoortia tyrannus NAS 1979). 

Black sea bass, Centropristis striata Muscle Elasmobranchs 6.4 DW 1... 

Foureman GL, Hernandez O, Bhatia A, et al. The stereoselectivity of four hepatic glutathione S-transferases purified from a marine elasmobranch (Raja erinacea) with several K-region polycyclic arene oxide substrates. Biochim Biophys Acta 1987 914(2) 127-135. 

Induction of aryl hydrocarbon hydroxylase activity in tele-ost fish (28, 1+1+) and elasmobranch (25.) has also been observed without a hypsochromic shift in the spectrum of the cytochrome P-1+50. CO complex. 

Hepatic microsomal and solubilized mixed-function oxidase systems from the little skate, Baja erinacea, a marine elasmobranch. In Ullrich, V., Hildebrandt, A., Roots, I., Eastabrook, R.W. (Eds.) Microsomes and Drug Oxidations (1976). Pergamon Press, Oxford, pp 16O-I69. 

In general, our studies with cytochrome P-450-dependent metabolism have emphasized the similarity of the hepatic MFO system in marine fish to that found in mammals. Thus, in the little skate (Raja erinaoea), a marine elasmobranch, enzyme activity is localized in the microsomal fraction, requires NADPH and molecular oxygen for maximum activity, and can be inhibited with CO (1, 2). Moreover, when hepatic microsomes from the little skate were solubilized and separated into cytochrome P-450, NADPH-cytochrome P-450 reductase, and lipid fractions, all three fractions were required for maximal MFO activity in the reconstituted system (3). We have also found, as have others, that the administration of polycyclic hydrocarbons (3-methylcholanthrene, 1,2,3,4-dibenzanthracene [DBA]), 2,3,7,8-tetrachlorodibenzo-p-dioxin... 

It is an ideal compound for regulation of osmotic pressure, since it has a low molecular mass, is highly soluble and has no net charge. It serves this function in some of the tissues of elasmobranch fish such as the skate and shark, and in marine invertebrates. Any damage to these tissues releases taurine, which is used as a chemoattractant for predators such as the shrimp, which wiU attack small fish. 

Elasmobranchs have their paired olfactory organs on the ventral side near the mouth. As the fish takes the respiratory water current into the mouth, water passes through the olfactory sacs. Thus, elasmobranches use the respiratory water current for supplying the olfactory organ with waterborne stimuli. 

In fish, both taste and olfactory stimuli are waterborne. However, taste involves the seventh, ninth or tenth cranial nerves, in contrast to the first cranial nerve for smell. Elasmobranchs have their taste buds in the mouth and pharynx, but in bony fish they occur around the gills, on barbels and pectoral fins, and also scattered over the rest of the body surface. They crowd particularly in the roof of the mouth, forming the palatal organ. The taste receptor cells are arranged as a bundle to form a taste bud. Like other vertebrates, fish have receptors for sweet, sour, salty, and bitter. For instance, goldfish reject quinine-treated food pellets (Jobling, 1995). Many fish species are particularly sensitive to acidic taste characteristics. The responses of fish to amino acids will be discussed in Chapter 12. 

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