scholarly journals The Role of N and C Termini in the Antifreeze Activity of Winter Flounder (Pleuronectes americanus) Antifreeze Proteins

2003 ◽  
Vol 278 (12) ◽  
pp. 10334-10343 ◽  
Author(s):  
Woon-Kai Low ◽  
Qingsong Lin ◽  
Choy L. Hew
1984 ◽  
Vol 62 (5) ◽  
pp. 839-844 ◽  
Author(s):  
G. L. Fletcher ◽  
M. J. King ◽  
C. L. Hew

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.


1980 ◽  
Vol 58 (5) ◽  
pp. 377-383 ◽  
Author(s):  
Choy L. Hew ◽  
Garth L. Fletcher ◽  
V. S. Ananthanarayanan

The antifreeze proteins (AFP) of the shorthorn sculpin, Myoxocephalus scorpius, were isolated and compared with the AFP of the winter flounder. The shorthorn sculpin was found to contain one major and one minor antifreeze protein with an approximate molecular weight of 10 000 – 11 000 in the winter. The major AFP was isolated and characterized. It had many characteristics in common with the flounder AFP studied in our laboratories. These characteristics included its seasonal appearance, size, amino acid composition, the abundance of alanine in the composition, the extent of antifreeze activity, and the nature of the secondary structure. It is suggested that both the sculpin and flounder AFP are structurally homologous and belong to the same type of polypeptide antifreeze.


1994 ◽  
Vol 51 (4) ◽  
pp. 933-941 ◽  
Author(s):  
Emily Monosson ◽  
John J. Stegeman

Cytochrome P4501A (CYP1A), Aroclor 1254 (A1254), and 3,3′,4,4′-tetrachlorobiphenyl (TCB) were measured in liver of winter flounder, Pleuronectes americanus, from Boston Harbor, Mass., Hempsted Harbor, N.Y., Niantic, Conn., and an offshore site, Georges Bank. We also measured CYP1A content and activity in flounder from Passamaquoddy Bay, N.B. Concentrations of A1254 and TCB were the least in fish from Georges Bank (0.46 and 0.002 μg∙g dry weight−1, respectively); concentrations in fish from Boston, Niantic, and Hempsted ranged from 7.6 to 11.3 μg∙g−1 and from 0.013 to 0.024 μg∙g−1. Immunodetected microsomal CYP1A contents (expressed as scup P450E equivalents) were 0.17 and 0.19 nmol∙mg−1 in fish from Georges Bank and Passamaquoddy and 0.25–0.41 nmol∙mg−1 in fish from Boston, Niantic, and Hempsted. Ethoxyresorufin-O-deethylase specific activities likewise were greater in fish from Boston, Niantic, and Hempsted (1.7–2.4 nmol∙min−1∙mg−1) than in fish from Georges Bank or Passamaquoddy (0.83 and 0.61 nmol∙min−1∙mg−1). CYP1A content and activity were correlated with hepatic concentrations of A1254 and TCB. These data, together with data reported in previous studies, indicate that strong induction of CYP1A protein occurs in winter flounder populations along most of the industrialized east coast and that induction of CYP1A is common, but less strong, at sites distant from the urban centers of the Northeast.


1993 ◽  
Vol 27 (13) ◽  
pp. 2759-2771 ◽  
Author(s):  
Lyndal L. Johnson ◽  
Carla M. Stehr ◽  
O. Paul Olson ◽  
Mark S. Myers ◽  
Susan M. Pierce ◽  
...  

1994 ◽  
Vol 51 (6) ◽  
pp. 1368-1375 ◽  
Author(s):  
V. Vignier ◽  
J. H. Vandermeulen ◽  
J. Singh ◽  
D. Mossman

7-Ethoxyresorufin-O-deethylase (EROD), benzo[a]pyrene hydroxylase (BaPH), and cytochromes P-450 (cyt-P450) and b5 (cyt-b5) varied annually in winter flounder (Pleuronectes americanus) collected in August of 1987, 1988, and 1989 from a coal tar contaminated estuary (Sydney, Nova Scotia, Canada). For August 1989, with fish available from all estuary areas, these indices correlated strongly with a spatial (along estuary) gradient in PAH in bottom sediments (7.19 ± 6.59–191 ± 184 μg g dry weight−1). Mean EROD activities in flounder near the coal tar source were up to seven times those in other estuary areas and paralleled sediment PAH loadings; however, standard deviations were high. Correlations for all MFO indices and sediment PAH were obtained in female flounder (P < 0.01: EROD, cyt-b5, cyt-P450; P < 0.02: BaPH). For male flounder the trend was similar, but only cyt-P450 correlated with sediment PAH (P < 0.017). BaPH activity was highest near the coal tar source but was more variable and less sensitive to pollutant levels than EROD activity. Somatic indices in fish from Sydney estuary and St. George's Bay were similar. Winter flounder are vulnerable to PAH-induced MFO activities from coal tar contaminated sediments, but MFO induction does not occur equally in all fish; single-season or single-year data must be interpreted with caution.


2018 ◽  
Vol 44 (6) ◽  
pp. 1527-1533 ◽  
Author(s):  
Miaomiao Xin ◽  
Jan Sterba ◽  
Anna Shaliutina-Kolesova ◽  
Borys Dzyuba ◽  
Jaroslava Lieskovska ◽  
...  

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