Sea scorpions

Figure 4 Oxygen consumption by Black Sea species during short-term hypoxia O, Annular gilthead (annular bream) A, sea scorpion , horse-mackerel. (After Stolbov etal., 1995.)...

Stolbov, A.Ya., Stavitskaya, E.N. and Shulman, G.E. (1997). Dynamics of oxygen consumption and nitrogen excretion in Black Sea scorpion fish in short- and longtime hypoxia (In Russian). DokladyAkademii Nauk 356,569-571. 

Kamenz C, Staude A, Dunlop JA. Sperm carriers in Silurian sea scorpions. Naturwissenschaften. 2011 98 889-96. 

Since sea snake venoms are discussed here, it is appropriate to review other vertebrate venoms also. Unfortunately, very few investigations have been done on the venoms of other marine vertebrates. It is known that some fish secrete venoms from their spines. The fishes known to have venoms are the scorpion fish (family Scorpaenidae), weever fish (family Trachinidae), catfish (order Siluriformes there are 31 families), stargazers (family Uranoscopidae), toad fish (family Batrachoidi-dae), and stingrays (suborder Myliobatoidea). 

Apart from AP-A, the best characterized of these polypeptides with respect to its biological activity is Anemonia sulcata toxin II (ATX II) [19]. This molecule is also cardioactive [28], as would be expected from its similarity to AP-A. Renaud et al. [29] have compared the activities of a number of sea anemone and scorpion toxins on isolated rat atria and found that anthopleurin-B (AP-B, also known as Ax II) had the highest potency and the greatest margin between the concentrations necessary for maximal inotropic activity and for provoking arrhythmias (0.3 versus 10 n . It was also found that sodium channels of rat cardiac cells in culture, which have a low affinity for tetrodotoxin (TTX), have a particularly high affinity for Type 1 anemone toxins [29], whereas Type 2 toxins [30] and scorpion toxins [31] had similar affinities for TTX-sensitive and TTX-insensitive channels in rat neuroblastoma cells and skeletal myotubes, respectively. 

Loret EP, Menendez Soto del Valle R, Mansuelle P, Sampieri F, Rochat H. Positively charged amino acid residues located similarly in sea anemone and scorpion toxins. J Biol Chem 1994 269 16785-16788. 

Catterall WA, Beress L. Sea anemone toxin and scorpion toxin share a common receptor site associated with the action potential sodium ionophore. J Biol Chem 1978 253 7393-7396. 

Bacteria, protozoa, and venomous animals synthesize numerous toxins that are used to kill their prey or to defend themselves. Sea anemones, jellyfish, cone snails, insects, spiders, scorpions, and snakes all make potent and highly specific neurotoxins. Plants form a host of alkaloids and other specialized products, some of which are specifically neurotoxic and able to deter predators. More than 500 species of marine cone snails of the genus Conus synthesize a vast array of polypeptide toxins (conotoxins), 487-489 some with unusual posttranslational modifications.490 491 The slow-moving snails are voracious predators that use their toxins, which they inject with a disposible harpoonlike tooth,492 to paralyze fish, molluscs, or worms.493... 

Serotonin is a very ancient neurotransmitter and has been found in the venom of amphibians, wasps, and scorpions and within the nematocysts of the sea anemone as well as in the nervous system of parasitic flatworms, crickets, and lobsters. Within the human body, 90% of the total serotonin is contained... 

Few studies aimed at understanding the effects of pressure on metabolism in fish have been performed in the Black Sea or Sea of Azov because no distinct stratification was found in the distribution of water animals there. The Sea of Azov is saucer-like, its maximum depth being only 15 m, and in the Black Sea the oxygenated water layer extends only to 150 m depth. However, Emeretli (1996) has shown that activity of lactate dehydrogenase in the liver increases 2-10 times in scorpion fish and annular bream placed in a barorespirometer (designed by A. Stolbov) and sunk to a depth of 300 m. This response seems to be peculiar to shallow-water species (Hochachka and Somero, 1984). 

Table 4 Lipid fractions in muscle and blood serum of horse-mackerel (active) and scorpion fish (sluggish) from the Black Sea, as mg % wet weight of tissue. (After Shchepkin, 1972.)...

Proteolytic digestive enzyme activity in sluggish Black Sea fish (e.g. toad goby, scorpion fish) has been found to be equal to and sometimes greater than that of the active fish (e.g. horse-mackerel, annular bream, pickerel). The aminolytic activity of fish of low mobility is also greater (Ugolev and Kuzmina, 1993). It will further be shown in Chapter 5 that the consumption and assimilation of food occur more efficiently in sluggish than in active fish. 

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