Antifreeze peptides confer freezing resistance to fish

1986 ◽  
Vol 64 (9) ◽  
pp. 1897-1901 ◽  
Author(s):  
Garth L. Fletcher ◽  
Ming H. Kao ◽  
Ron M. Fourney
Keyword(s):  
Seasonal Changes ◽  
Antifreeze Proteins ◽  
Antifreeze Protein ◽  
Winter Flounder ◽  
Salmo Gairdneri ◽  
Pseudopleuronectes Americanus ◽  
Freezing Resistance ◽  
Protein Levels ◽  
Protein Receptors ◽  
Species Specific

It has been widely accepted that plasma antifreeze proteins are directly responsible for the ability of many marine teleosts to survive in ice-laden seawater. However, there appears to be no direct experimental evidence to indicate that this assumption is correct. In the present study winter flounder (Pseudopleuronectes americanus) showed seasonal changes in freezing resistance that were quantitatively the same as the seasonal changes in plasma antifreeze protein levels. Moreover, when winter flounder antifreeze proteins were injected into rainbow trout (Salmo gairdneri) (a species that does not normally possess antifreeze proteins) they increased the freezing resistance of the trout in direct proportion to plasma antifreeze protein levels attained. These studies indicate that antifreeze proteins are directly responsible for the ability of many marine teleosts to survive icy seawater at temperatures below the colligative freezing points of their blood. There appears to be no requirement for species-specific antifreeze protein receptors in the fish in order for them to act.

Fish antifreeze proteins: physiology and evolutionary biology

1988 ◽  
Vol 66 (12) ◽  
pp. 2611-2617 ◽  
Author(s):  
Peter L. Davies ◽  
Choy L. Hew ◽  
Garth L. Fletcher
Keyword(s):  
Fish Species ◽  
Evolutionary Biology ◽  
Antifreeze Proteins ◽  
Structural Diversity ◽  
Antifreeze Protein ◽  
Pituitary Hormones ◽  
Endogenous Rhythms ◽  
Protein Levels ◽  
Wide Range ◽  
High Concentrations

Many marine teleosts have adapted to ice-laden seawater by evolving antifreeze proteins and glycoproteins. These proteins are synthesized in the liver for export to the blood where they circulate at levels of up to 20 mg/mL. There are at least four distinct antifreeze protein classes differing in carbohydrate content, amino acid composition, protein sequence, and secondary structure. In addition to antifreeze structural diversity, fish species differ considerably with respect to mechanisms controlling seasonal regulation of plasma antifreeze concentrations. Some species synthesize antifreeze proteins immediately before the onset of freezing conditions, some synthesize them in response to such conditions, whereas others possess high concentrations all year. Endogenous rhythms, water temperature, photoperiod, and pituitary hormones have all been implicated as regulators of plasma antifreeze protein levels. The structural diversity of antifreeze proteins and their occurrence in a wide range of fish species suggest that they evolved separately and recently during Cenozoic glaciation. Invariably, the genes coding for these antifreeze proteins are amplified, sometimes as long tandem arrays, suggesting intense selective pressure to produce large amounts of protein. The distribution of antifreeze gene types among fish species suggests that they could serve as important tools for studying phylogenetic relationships.

How does the brain control the pituitary's release of antifreeze synthesis inhibitor?

1984 ◽  
Vol 62 (5) ◽  
pp. 839-844 ◽  
Author(s):  
G. L. Fletcher ◽  
M. J. King ◽  
C. L. Hew
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Antifreeze Proteins ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Synthesis Inhibitor ◽  
Pituitary Glands ◽  
The Central Nervous System ◽  
The Brain ◽  
Antifreeze Activity

Previous studies of winter flounder (Pseudopleuronectes americanus) demonstrated that the pituitary inhibits the synthesis of antifreeze proteins during the summer and that the inhibition is removed with the approach of winter. Assuming that the pituitary is under the control of the central nervous system, the question posed was, Does the central nervous system stimulate the release of the pituitary antifreeze inhibitory factor during the summer or inhibit its release during the winter? Two experiments were carried out. In the first, flounder were hypophysectomized and a number of them were given pituitary autotransplants prior to the spring loss of plasma antifreeze. During July, flounder containing functional autotransplants had lost the capacity to synthesize antifreeze proteins and their plasma antifreeze activity had disappeared. In the second experiment, hypophysectomy and pituitary transplantation was carried out in the fall prior to the winter onset of antifreeze biosynthesis. Flounder containing functional auto- or homo-transplants showed no evidence of plasma antifreeze activity, whereas intact controls and hypophysectomized flounder had levels typical of winter fish. These results indicate that the central nervous system normally inhibits the pituitary glands release of antifreeze inhibitor during the winter.

Evidence for Antifreeze Protein Gene Transfer in Atlantic Salmon (Salmo salar)

1988 ◽  
Vol 45 (2) ◽  
pp. 352-357 ◽  
Author(s):  
Garth L. Fletcher ◽  
Margaret A. Shears ◽  
Madonna J. King ◽  
Peter L. Davies ◽  
Choy L. Hew
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Cold Water ◽  
Restriction Enzymes ◽  
Antifreeze Protein ◽  
Winter Flounder ◽  
Control Fish ◽  
Pseudopleuronectes Americanus ◽  
Atlantic Salmon Salmo Salar ◽  
Antifreeze Polypeptides

Atlantic salmon (Salmo salar) freeze to death if they come into contact with ice at water temperatures below −0.7 °C. Consequently, sea-pen culture of this species in cold water is severely limited. Winter flounder (Pseudopleuronectes americanus) survive in ice-laden seawater by producing a set of antifreeze polypeptides (AFP). We are attempting to make the Atlantic salmon more freeze resistant by transferring antifreeze protein genes from the winter flounder to the genome of the salmon. Salmon eggs were microinjected with linearized DNA after fertilization. Individual fingerlings (1–2 g) were analyzed for flounder AFP genes by genomic Southern blotting. DNA from 2 out of 30 fingerlings showed hybridization to the flounder DNA probe. Hybridization bands following cleavage by restriction enzymes Sst l and Bam HI were identical to those of the injected DNA. Hybridization following Hind III digestion indicated that the flounder AFP gene was linked to the salmon genome. These hybridization signals were absent in the DNA from control fish. The intensity of the hybridization signals indicated that there was on average at least one copy of the AFP gene present per cell.

Tissue distribution of fish antifreeze protein mRNAs

1992 ◽  
Vol 70 (4) ◽  
pp. 810-814 ◽  
Author(s):  
Zhiyuan Gong ◽  
Garth L. Fletcher ◽  
Choy L. Hew
Keyword(s):  
Northern Blot Analysis ◽  
Antifreeze Protein ◽  
The Body ◽  
Winter Flounder ◽  
Type I ◽  
Pseudopleuronectes Americanus ◽  
Sea Raven ◽  
Hemitripterus Americanus ◽  
Afp Mrna ◽  
Distribution Of Fish

The presence of fish antifreeze protein (AFP) mRNA was examined in a variety of tissues from the winter flounder (Pseudopleuronectes americanus), sea raven (Hemitripterus americanus), and ocean pout (Macrozoarces americanus), each of which contains one of the three known AFP types. Northern blot analysis indicates that whereas the AFP mRNA is restricted to liver in sea raven (type II AFP), significant amounts of mRNA are present in many other tissues in both winter flounder (type I) and ocean pout (type III). These results indicate that in sea raven, antifreeze protein synthesis only occurs in the liver, whereas in the ocean pout and winter flounder, synthesis occurs in many tissues throughout the body. These investigations are relevant to understanding the mode of action of these polypeptides.

The effects of hypophysectomy on seasonal changes in plasma freezing-point depression, protein 'antifreeze,' and Na+ and Cl− concentrations of winter flounder (Pseudopleuronectes americanus)

1978 ◽  
Vol 56 (1) ◽  
pp. 109-113 ◽  
Author(s):  
G. L. Fletcher ◽  
C. M. Campbell ◽  
C. L. Hew
Keyword(s):  
Seasonal Changes ◽  
Freezing Point ◽  
Early Summer ◽  
Winter Flounder ◽  
Day Length ◽  
Freezing Point Depression ◽  
Pseudopleuronectes Americanus ◽  
Ambient Seawater ◽  
Annual Increase ◽  
Annual Changes

The annual changes in plasma Na+ and Cl− concentrations took place in the absence of the pituitary, although the magnitude of the change was significantly reduced. The annual increase in plasma freezing-point depression also occurred in the absence of the pituitary. However the decrease normally observed in the spring and early summer did not occur.Sham-operated winter flounder transferred from ambient seawater (−1 °C) and day length to warm water (6–12 °C) and 18-h day length showed a reduction in plasma Cl− concentration and freezing-point depression and a loss of the protein 'antifreeze.' Hypophysectomized flounder treated in the same way showed a reduction in plasma Cl−, but no decline in freezing-point depression and protein 'antifreeze.'These results suggest that an intact pituitary is necessary for the disappearance of the protein 'antifreeze' from the plasma of the winter flounder.

Freezing resistance in winter flounder Pseudopleuronectes americanus

Nature ◽  
1974 ◽  
Vol 247 (5438) ◽  
pp. 237-238 ◽  
Author(s):  
JOHN G. DUMAN ◽  
ARTHUR L. DEVRIES
Keyword(s):  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Freezing Resistance

Seasonal dynamics of Cu2+, Zn2+, Ca2+, and Mg2+ in gonads and liver of winter flounder (Pseudopleuronectes americanus): evidence for summer storage of Zn2+ for winter gonad development in females

1978 ◽  
Vol 56 (2) ◽  
pp. 284-290 ◽  
Author(s):  
G. L. Fletcher ◽  
M. J. King
Keyword(s):  
Seasonal Dynamics ◽  
Seasonal Changes ◽  
Gonad Development ◽  
Winter Flounder ◽  
Feeding Period ◽  
Pseudopleuronectes Americanus ◽  
Male And Female ◽  
Ovary Weight ◽  
Ovarian Growth ◽  
Sexually Mature

The concentrations and total amounts of Zn2+, Cu2+, Mg2+, and Ca2+ were measured in the gonads and livers of sexually mature winter flounder caught at approximately monthly intervals in Chapel's Cove, Newfoundland.The winter flounder fed from April through to October each year. Male and female gonads initiated development in August and spawned in June. The maximum testes weight was observed in October corresponding to the end of the feeding period. The maximum ovary weight was not observed until February, indicating that considerable ovarian growth occurred after feeding had stopped.All four metals in the gonads and livers exhibited seasonal changes. The ovaries accumulated four to six times more Zn2+, Cu2+, and Ca2+ than did the testes. The testes accumulated more Mg2+ than did the ovaries during annual development. The ovaries continued to incorporate all four metals after the fish had stopped eating. Some of the ovaries postfeeding requirements for Zn2+ and Cu2+ could have been met by utilizing liver stores. However, most of the ovaries requirements for Zn2+ must have been obtained from other storage areas in the fish. The ovaries postfeeding requirements for Cu2+, Ca2+, and Mg2+ could have been obtained by the flounder absorbing these metals from the seawater.

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