Fish, Arctic and Antarctic

As to other organic substances in this context, special mention must be made of glycoproteins, which prevent blood from freezing in Arctic and Antarctic fish (De Vries, 1970 Hochachka and Somero, 1973). Glycoprotein, composed of repeated subunits of alanine and threonine bound to a disaccharide derivative of galactose, is an antifreeze agent (DeVries, 1971 Shier et al., 1972). It impedes crystal formation in blood and lowers the freezing point to -1.8°C, the lowest... 

Zimmermann, C. and G. Hubold (1998). Respiration and activity of Arctic and Antarctic fish with different modes of life A multivariate analysis of experimental data. In Fishes of Antarctica. A Biological Overview, pp. 163-174, ed. G. di Prisco, E. Pisano, and A. Clarke. Milan Springer. 

Biological antifreezes constitute a diverse class of proteins found in Arctic and Antarctic fish, as well as in amphibians, trees, plants and insects. These compounds are unique in that they have the ability to inhibit the growth of ice and consequently, are essential for the survival of organisms inhabiting environments where sub-zero temperatures are routinely encountered. 

The preparation and properties of anti-freeze glycoproteins from Arctic and Antarctic fish blood have been reviewed.In a c.d. spectroscopic study of... 

The so-called antifreeze glycoproteins protect Arctic and Antarctic fish species at ambient temperatures (—1.8 °C) at which their blood should normally freeze. The fundamental structures of a number of these glycoproteins contain repeating sequences of the tripeptide L-alanyl-L-alanyl-L-threonine with sugars linked glycosidically to the L-threonine residues. Antifreeze glycoproteins isolated... 

A unique family of O-linked glycoproteins permits fish to live in the icy seawater of the Arctic and Antarctic regions where water temperature may reach as low as — 1.9°C. Antifreeze glycoproteins (AFGPs) are found in the blood of nearly all Antarctic fish and at least five Arctic fish. These glycoproteins have the peptide structure... 

Polychlorinated biphenyls (PCBs) are a family of compounds that were used extensively in electrical equipment, such as transformers, because of their insulating and heat transferring qualities. They are suspected human carcinogens and have been linked to liver, kidney, and other health problems. It is known that PCBs can be transported by air, and this is thought to be one of the major ways in which they circulate around the world, explaining why they are found in the Arctic and Antarctic. Indian women dwelling on Cornwall Island located in the Canadian portion of the reservation have elevated levels of toxic PCBs in their breast mUk. The PCB contamination does not appear to come from fish, but from air the women breathe every day [45]. 

Fish living in Arctic and Antarctic waters may encounter temperatures as low as -1.9°C. The freezing point depression provided by dissolved salts and proteins in the blood is insufficient to protect the fish from freezing. As winter approaches, they synthesize and accumulate in their blood serum a series of eight or more special antifreeze proteins.a d One type of antifreeze glycoprotein from winter flounder contains the following unit repeated 17-50 times. 

On a global basis for all species, oils produced in the tropics are more completely saturated and have the highest melting points, with melting points decreasing with distance from the equator (in north and south latitudes). Many dietary fatty acids are transposed from plant or plankton feed sources to body tissues, and fish oils from the Arctic and Antarctic species generally melt at lower temperatures than those... 

DDT has been reported in the fat of Eskimos in the Arctic and in fish according to Durham (7), and in Weddell seals and Adelie penguins in the Antarctic according to George (8). In these remote areas any form of direct contamination is out of the question and we must turn to the sea and air for the source. Certainly the sea, or the life dwelling in it, is a prime suspect. We cannot, however, rule out air-borne contamination. Ice laid down in 1964 on Mt. Olympus, in the state of Washington, has been found to contain 0.3 p.p.b. of DDT [cited by Metcalf... 

The 0-linked saccharides are not as common as the A-linked saccharides. A relatively simple saccharide is that attached to L-threonine of the highly glyosylated (1 out of every 3 amino acid residues), antifreeze protein found in the blood sera of fish living in the Arctic and Antarctic waters. This glycoside is a disaccharide, -D-Galp-(1 3)-cz-D-GalNAc p [147]. 

Vincent WF, Layboum-Parry J (2008) Polar lakes and rivers Limnology of Arctic and Antarctic aquatic ecosystems. Oxford University Press, New York Vincent WF, Vincent CL (1982) Factors controlling phytoplankton production in Lake Vanda (77 S). Canadian J Fish Aquat Sci 39 1602-1609... 

Arctic and Antarctic insects, fish, amphibians, and reptiles naturally produce cryoprotectants to minimize freezing damage during cold spells. Insects commonly use sugars or polyols (alcohols) as cryoprotectants. Arctic frogs use glucose, and Arctic salamanders produce glycerol in their livers for use as cryoprotectant. 

Yu, Y., T.L. Wade, J. Fang, S. McDonald, and J.M. Brooks. 1995. Gas chromatographic-mass spectrometric analysis of polycyclic aromatic hydrocarbon metabolites in Antarctic fish (Notothenia gibberifrons) injected with Diesel Fuel Arctic. Arch. Environ. Contam. Toxicol. 29 241-246. 

Another major difference between certain Arctic fishes and Antarctic notothenioids is the occurrence of a second family of AFPs in the former fishes skin AFPs. The discovery by Gong et al. (1996) that AFPs may exist within cells as well as in the extracellular fluids, and that the intracellular AFPs are encoded by a set of genes distinct from those encoding extra-... 

The glycoproteins from the Antarctic fishes and the Arctic polar cod have repeated amino acid sequences of Ala-Ala-Thr in their backbone polypeptide structure. Furthermore, disaccharide groups are regularly attached to all the threonine residues through a link-... 

The congealing temperature of the blood serum of polar fish of Arctic or Antarctic regions (e. g. Trematomus borchgrevinski, Dissostichus maw-soni, Boreogadus saida) is about — 2 °C and thus is significantly lower than that of other fish (—0.6 to — 0.8 °C). Antifreeze gly-coproteins account for such low values. The amino acid sequence of this class of proteins is characterized by high periodicity ... 

Figure 7.39. The diversity of antifreeze proteins and antifreeze glycoproteins in marine fishes. Shown are the structures of four types of AFPs (I-IV) and the AFGP found in Antarctic notothenioids and Arctic cod. AFPs I-IV are shown as ribbon structures. The tripeptide repeat (-ala-ala-thr-) and carbohydrate moiety (galactosyl-lV-acetylgalactosamine) of AFGPs illustrate the key element of AFGP structures in noto-thenioid and Arctic cod.

The seasonal variation in thermal hysteresis found in D. canadensis is due to more than shifts in concentrations of THPs, however. Unlike the freezing-avoidance strategy of Antarctic and Arctic fishes, in which the amount of thermal hysteresis appears to be due strictly to the concentration of THPs in the body fluids, freeze-avoiding insects employ a complex set of mechanisms to achieve the high levels of thermal hysteresis found for hemolymph in winter-collected specimens. 

---