Serum composition of the coelacanth, Latimeria chalumnae Smith

Abstract

Inorganic and organic constituents were studied on blood serum collected from a living specimen of the coelacanth, Latimeria chalumnae.Inorganic electrolytes determined included sodium (196.7 mM/l), potassium (5.78 mM/l), magnesium (5.30 mM/l), calcium (4.94 mM/I), chloride (186.7 mM/l), bicarbonate (9.60 mM/l), phosphate (5.08 mM/l), and sulfate (4.80 mM/l). Serum urea (377 mM/l) and trimethylamine oxide (122 mM/1) were high as previously reported, and accounted for the bulk of the total non-protein nitrogen (1199 mg%)); total amino acids added a small but not insignificant fraction (21.9 mg%). High serum lactate (16.5 mM/1) and glucose (6.57 mM/1) levels were probably indicative of stress; glucose was the only carbohydrate present in appreciable amounts in the serum, although traces of glucuronic acid and rhamnose were found. Serum total cholesterol was 3.91 mM/l, organically bound phosphorus 1.99 mM/1 and total proteins 2.84 g % . Three major protein fractions were evident from cellulose acetate electrophoresis and at least 11 peaks were demonstrable by acrylamide gel electrophoresis. Latimeria serum lacks a protein component with a mobility approaching that of human serum albumin, Serum osmolarity (932 mOsm/l) was somewhat lower than that of sea water collected at the site of capture of' the specimen (1035 mOsm/l). Evolutionary implications of the similarity of Latimeria scrum chemistry to that of other marine fishes are discussed.

Guppies, toadfish, lungfish, coelacanths and frogs: a scenario for the evolution of urea retention in fishes

“…Only when the companion paper by Brown & Brown (1967) on ureogenesis in L. chalumnae was submitted, was Pickford & Grant's paper con-sidered acceptable. With new data on levels of urea and other solutes in blood and other fluids from the frozen-thawed VIMS specimens combined with published data on other frozen-thawed and living coelacanths (Pickford & Grant 1967, Lutz & Robertson 1971, Rasmussen 1979, Cole 1968, Griffith et al 1974, 1975 it is now possible to provide those elusive standard errors to satisfy that overzealous reviewer (Table 2). Data from Griffith (1981) on an elasmobranch, the blue shark Prionace glauca, are also presented for comparison.…”

“…While it is doubtful that definitive evidence for or against the homology of ureosmotic regulation in Latimeria and chondrichthians will ever arise, significant differences in the ability of the kidneys to reabsorb urea (Griffith et al 1974), disparity in mechanisms of internal fertilization (a necessary concomitant of ureosmotic regulation in fishes ), and the occurrence of ureosmotic regulation in the frog Rana cancrivora (Gordon et al 1961) suggest that the feature was surely independently evolved twice, probably thrice and that it is of questionable taxonomic value.…”

Intestinal anion exchange in marine fish osmoregulation

“…(1) Osmoconformity/ionoconformity is found in the strictly marine agnathan hagfishes, which do not appear to regulate osmotic pressure and concentrations of main osmolytes to a great extent in seawater (Morris, 1958). (2) Osmoconformity and ionoregulation are seen in marine elasmobranchs (Hazon et al, 2003) and in the lobe-finned coelacanth (Griffith et al, 1974), which maintains plasma osmolality at or slightly above that of the surrounding seawater but NaCl concentrations at approximately d of ambient levels. (3) The most common strategy is osmoregulation, found in all teleosts (Marshall and Grosell, 2005) and marine lampreys (Morris, 1958), achieved by the regulation of the main extracellular electrolyte (Na + and Cl -) levels at approximately d of full strength seawater.…”

Ultrastructure du parenchyme sécréteur de la glande postanale du cælacanthe, <i>Latimeria chalumnae</i> Smith

“…Cette apparence «com posite» a été maintes fois relevée au niveau d'ensembles aussi divers que le système ner veux central, l'appareil excréteur, l'appareil reproducteur ou bien encore les paramètres biochimiques ou physiologiques. Parmi ceuxci, un certain nombre de faits montrent cepen dant une affinité vis-à-vis des sélaciens et, à un moindre degré, des holocéphales: possession d'auricules cérébelleuses développées et ab sence de valvule cérébelleuse [Millot et An thony, 1958: Lemire, 1971, organisation du système hypothalamo-hypophysaire [Lagios, 1975: Van Kemenade et Kremers, 1975, pré sence de glomérules rénaux volumineux [Millot et Anthony, 1973] et de cellules juxtaglomé-rulaires dans les artères rénales [Lagios, 1974], structures des îlots pancréatiques [Epple et Brinn, 1975], découverte d'oeufs de grande taille dans une femelle mature [Anthony et M illot, 1972;Griffith et Thomson, 1973] et ovoviviparité [Smith et al, 1975], composition chimique du cartilage [Mathews, 1966], isoosmolarité plasmatique [Griffith et al, 1974], rétention d'urée [Pickford et Grant, 1967: L utiet Robertson, 1971Goldstein et a i, 1972], La possession d'une glande «à sels», anatomi quement et physiologiquement comparable, peut en être un autre exemple.…”