Oocyte Maturation and Ovulation Induced in Hypophysectomized Winter Flounder (Pseudopleuronectes americanus) by Preparations from Pituitary Glands of American Plaice (Hippoglossoides platessoides)

1977 ◽  
Vol 34 (11) ◽  
pp. 2142-2150 ◽  
Author(s):  
C. M. Campbell ◽  
D. R. Idler
Keyword(s):  
Key Words ◽  
Oocyte Maturation ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Con A ◽  
Pituitary Glands ◽  
Hippoglossoides Platessoides

Hypophysectomized winter flounder (Pseudopleuronectes americanus) did not undergo spontaneous oocyte maturation, but the glycoprotein fraction of extracts of American plaice (Hippoglossoides platessoides) pituitaries induced maturation and ovulation. The nonglycoprotein fractions, previously shown to contain a vitellogenic factor, were less efficient than the glycoprotein fractions in the induction of maturation and ovulation. The activity of the nonglycoprotein fraction was further reduced by rechromatography on Con-A Sepharose, suggesting that its action on oocyte maturation and ovulation was due to contamination by the glycoprotein gonadotropin. Key words: hypophysectomy, gonadotropin, oocyte, maturation, ovulation, vitellogenesis, flounder, plaice, Pseudopleuronectes, Hippoglossoides

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.

Feeding chronology and daily ration calculations for winter flounder (Pseudopleuronectes americanus), American plaice (Hippoglossoides platessoides), and ocean pout (Macrozoarces americanus) in Passamaquoddy Bay, New Brunswick

1987 ◽  
Vol 65 (3) ◽  
pp. 499-503 ◽  
Author(s):  
J. Stevenson Macdonald ◽  
Kenneth G. Waiwood
Keyword(s):  
Consumption Rate ◽  
Winter Flounder ◽  
Analysis Of Covariance ◽  
Fish Length ◽  
Benthic Fish ◽  
Daily Ration ◽  
Pseudopleuronectes Americanus ◽  
Gastric Evacuation ◽  
Passamaquoddy Bay ◽  
Hippoglossoides Platessoides

Feeding chronologies of three species of cohabiting benthic fish, winter flounder (Pseudopleuronectes americanus), ocean pout (Macrozoarces americanus), and American plaice (Hippoglossoides platessoides), are described. The volume of food eaten by each species at each of four collection times over 24 h was analysed using analysis of covariance (ANCOVA), with fish length as the covariate. Daily ration was estimated using a gastric evacuation model, incorporating mean stomach volumes at four subdaily intervals and independent evacuation rates for slower (bivalves) and faster digested prey (amphipods and polychaetes). Winter flounder, American plaice, and ocean pout were daylight feeders with American plaice feeding more heavily later in the day. Winter flounder had the highest consumption rate (1.77% body weight/day) followed by ocean pout (1.68%) and American plaice (1.28%). Estimates of daily and subdaily food consumption were compared with corresponding estimates based on prey-specific state of digestion indices. This study indicates that estimating total and individual prey consumption at subdaily intervals provides a useful tool in determining feeding chronology and draws attention to potential biases encountered when more traditional analyses are used.

Further Evidence for a Three-Year Oocyte Maturation Time in the Winter Flounder (Pseudopleuronectes americanus)

1970 ◽  
Vol 27 (5) ◽  
pp. 957-960 ◽  
Author(s):  
R. S. Dunn
Keyword(s):  
Oocyte Maturation ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Maturation Time ◽  
Size Groups

Evidence is presented for autumn growth of yolkless oocytes, which would tend to split the oocytes into two size groups.

Rates of Digestion of Different Prey in Atlantic Cod (Gadus morhua), Ocean Pout (Macrozoarces americanus), Winter Flounder (Pseudopleuronectes americanus), and American Plaice (Hippoglossoides platessoides)

1982 ◽  
Vol 39 (5) ◽  
pp. 651-659 ◽  
Author(s):  
J. Stevenson Macdonald ◽  
Kenneth G. Waiwood ◽  
Roger H. Green
Keyword(s):  
Goodness Of Fit ◽  
Gadus Morhua ◽  
Prey Species ◽  
Atlantic Cod ◽  
Graphical Analysis ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Evaluation Procedures ◽  
Visual Index ◽  
Hippoglossoides Platessoides

Stomachs of ocean pout (Macrozoarces americanus), Atlantic cod (Gadus morhua), winter flounder (Pseudopleuronectes americanus), and American plaice (Hippoglossoides platessoides) were removed and dissected 5, 12, 20, and 30 h after the fish had fed voluntarily to test the evacuation rates of three different prey species. Two evaluation procedures were used: a visual index of recognizabiiity, and a graphical analysis of percent of each prey recovered versus time since feeding. Three decay models were tested for goodness of fit to the evacuation data. The polychaete worms were the first to become unrecognizable, followed by amphipods. These species showed significantly different rates of evacuation when compared with the bivalves which were recognizable for the longest time. The exponential decay curve gave the best overall fit to the data. However, a linear model gave a good or better fit to the decay rate of the bivalve. The evacuation rates of different prey should be considered in estimating daily rations of fish in their environment.Key words: digestion, stomach content, food organism, Yoldia sapotilla, Tmetonyx cicada, Nephtys incisa

Studies of the Trematode Stephanostomum baccatum (Nicoll, 1907): I. The Distribution of the Metacercaria in Eastern Canadian Flounders

1954 ◽  
Vol 11 (6) ◽  
pp. 954-962 ◽  
Author(s):  
R. W. Wolfgang
Keyword(s):  
North American ◽  
Larval Stage ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Passamaquoddy Bay ◽  
The Witch ◽  
Species Being ◽  
Hippoglossoides Platessoides

Stephanostomum baccatum, an acanthocolpid trematode, encysts during its larval stage in eastern Canadian flounders, the most consistently and heavily infected species being the winter flounder, Pseudopleuronectes americanus (Walbaum). The infection is heaviest in Passamaquoddy Bay. Hosts are usually more heavily infected in inshore than in offshore waters. Infections are light in the Bras d'Or Lakes and the northern Gulf of St. Lawrence. Larger fish have heavier infections than smaller fish. S. baccatum infects both European and North American flounders; two of its hosts occur on both sides of the Atlantic: the witch, Glyptocephalus cynoglossus (L.), and the American plaice (European long rough dab), Hippoglossoides platessoides (Fabric.).

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