The influence of temperature on histological and radiochemical measurements of thyroid activity in the eastern brook trout, Salvelinus fontinalis Mitchell

1968 ◽  
Vol 46 (1) ◽  
pp. 1-9 ◽  
Author(s):  
D. E. Drury ◽  
J. G. Eales
Keyword(s):  
Epithelial Cell ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acclimation Temperature ◽  
Thyroid Follicle ◽  
Thyroid Activity ◽  
Cell Height ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
T Values

Histological and radiochemical techniques for assessing thyroid activity were compared on yearling brook trout acclimated at 5, 12, and 15 °C.The mean thyroid follicle epithelial cell height was 7.4 μ (range 6.0–8.6 μ) at 5 °C; 3.5 μ (range 2.9–3.9 μ) at 12 °C, and 2.3 μ (range 1.9–2.9 μ) at 15 °C. Assuming that a taller epithelial cell height indicates greater thyroid activity, then an inverse relationship between thyroid activity and acclimation temperature exists.Both the uptake of radioiodide by the thyroid (T/S) and the clearance of radioiodide from the serum were greater at higher temperatures. Serum PB125I production was negligible within 8 days after radioiodide injection and the conversion ratio could not be applied as an index of thyroid function, Assuming, however, that the thyroid radioiodide uptake is an index of thyroid activity, then there is a direct relationship between thyroid activity and acclimation temperature.In view of the marked discrepancy between these histological and radiochemical techniques, fractional rates of turnover of serum thyroxine were compared by determining the biological half-life (t½) for serum PB125I after L-thyroxine-125I intraperitoneal injection at different temperatures. The serum PB125I clearance curves were complex and tentative t½ values of 18.0 days (5 °C, 3.2 days (12 °C), and 1.5 days (15 °C) were obtained. These results indicate a more rapid serum PBI turnover at higher temperatures and support the radiochemical measurements.

Influence of acclimation temperature on rate constants for thyroid uptake of iodide by brook trout, Salvelinus fontinalis (Mitchill)

1971 ◽  
Vol 49 (5) ◽  
pp. 783-786 ◽  
Author(s):  
Carolyn D. Smith ◽  
J. G. Eales
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acclimation Temperature ◽  
Thyroid Activity ◽  
Iodide Uptake ◽  
Individual Fish ◽  
Thyroid Uptake

A procedure for determining the rate constant for thyroid iodide uptake for fish is described.Rate constants for thyroid iodide uptake in brook trout agreed with previously used indices of thyroid activity (T/S and CR) in indicating a more active thyroid at 16C than 10C.At both temperatures radioiodide metabolism was extremely slow with considerable variation between individual fish. These features may be attributed to the high and variable serum stable iodide level in this species.

scholarly journals Molecular and physiological responses predict acclimation limits in juvenile brook trout (Salvelinus fontinalis)

2021 ◽  
Vol 224 (16) ◽  
Author(s):  
Theresa E. Mackey ◽  
Caleb T. Hasler ◽  
Travis Durhack ◽  
Jennifer D. Jeffrey ◽  
Camille J. Macnaughton ◽  
...  
Keyword(s):  
Heat Shock ◽  
High Temperatures ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acute Stress ◽  
Physiological Responses ◽  
Heat Shock Protein 90 ◽  
Acclimation Temperature ◽  
Muscle Lactate ◽  
Air Exposure

ABSTRACT Understanding the resilience of ectotherms to high temperatures is essential because of the influence of climate change on aquatic ecosystems. The ability of species to acclimate to high temperatures may determine whether populations can persist in their native ranges. We examined physiological and molecular responses of juvenile brook trout (Salvelinus fontinalis) to six acclimation temperatures (5, 10, 15, 20, 23 and 25°C) that span the thermal distribution of the species to predict acclimation limits. Brook trout exhibited an upregulation of stress-related mRNA transcripts (heat shock protein 90-beta, heat shock cognate 71 kDa protein, glutathione peroxidase 1) and downregulation of transcription factors and osmoregulation-related transcripts (nuclear protein 1, Na+/K+/2Cl− co-transporter-1-a) at temperatures ≥20°C. We then examined the effects of acclimation temperature on metabolic rate (MR) and physiological parameters in fish exposed to an acute exhaustive exercise and air exposure stress. Fish acclimated to temperatures ≥20°C exhibited elevated plasma cortisol and glucose, and muscle lactate after exposure to the acute stress. Fish exhibited longer MR recovery times at 15 and 20°C compared with the 5 and 10°C groups; however, cortisol levels remained elevated at temperatures ≥20°C after 24 h. Oxygen consumption in fish acclimated to 23°C recovered quickest after exposure to acute stress. Standard MR was highest and factorial aerobic scope was lowest for fish held at temperatures ≥20°C. Our findings demonstrate how molecular and physiological responses predict acclimation limits in a freshwater fish as the brook trout in the present study had a limited ability to acclimate to temperatures beyond 20°C.

Iodide and thyroxine metabolism in the brook trout, Salvelinus fontinalis (Mitchill), during sustained exercise

1971 ◽  
Vol 49 (9) ◽  
pp. 1255-1269 ◽  
Author(s):  
D. A. Higgs ◽  
J. G. Eales
Keyword(s):  
Thyroid Hormone ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Specific Activity ◽  
Hormone Secretion ◽  
Conversion Ratio ◽  
Limited Extent ◽  
Thyroid Activity ◽  
Individual Variations ◽  
Serum Ratio

Iodide and thyroxine metabolism were followed in exercised and non-exercised starved trout.Radioiodide (125I) parameters suggested a slight increase in thyroid activity (% dose in thyroid, thyroid/serum ratio (T/S), and conversion ratio (CR)) and an increase in extrathyroidal 125I excretion resulting from exercise.The generally high and variable serum 127I levels increased up to 496 μg% during the experiments, being consistently higher in exercised fish. Individual variations in serum 127I were related in many instances to radioiodide parameters (I125I, T/S, CR) and to a limited extent to % thyroid. This demonstrates the uncertainty of radioiodide measurements when the specific activity of circulating 125I changes and the need for assessing 127I levels in radioiodide studies.Tissue uptake of radioactivity and serum loss of protein-bound radioactivity following radiothyroxine intraperitoneal injection, as well as serum stable thyronine levels, suggested both increased biliary loss of thyroid hormones and a higher thyroid hormone secretion rate as the result of exercise.

scholarly journals Molecular and physiological responses predict acclimation limits in juvenile brook trout (Salvelinus fontinalis)

2020 ◽  
Author(s):  
Theresa E. Mackey ◽  
Caleb T. Hasler ◽  
Travis Durhack ◽  
Jennifer D. Jeffrey ◽  
Camille J. Macnaughton ◽  
...  
Keyword(s):  
Heat Shock ◽  
Metabolic Rate ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Transcript Abundance ◽  
Acclimation Temperature ◽  
Temperature Threshold ◽  
Plasma Parameters ◽  
Muscle Lactate ◽  
Air Exposure

AbstractBrook trout (Salvelinus fontinalis) populations are at risk of exposure to high water temperatures in the species’ native range in eastern North America. We quantified the physiological and molecular responses of juvenile brook trout to six acclimation temperatures that span the thermal distribution of the species (5, 10, 15, 20, 23, and 25°C). Using quantitative PCR (qPCR), we measured the mRNA transcript abundance of temperature-induced cellular stress genes to identify a potential sub-lethal temperature threshold for brook trout between 20–23°C. Brook trout exhibited an upregulation of stress-related genes (heat shock protein 90-beta; heat shock cognate 71 kDa protein; glutathione peroxidase 1) and a downregulation of transcription factors and osmoregulation-related genes (Na+/K+/2Cl− co-transporter-1-a; nuclear protein 1) at temperatures ≥20°C. We also used respirometry to assess the effects of the acclimation temperatures on oxygen consumption. Standard metabolic rate results indicated that energy expenditure was higher at temperatures ≥20°C. We then examined the effects of acclimation temperature on metabolic rate and blood plasma parameters in fish exposed to an acute exhaustive exercise and air exposure stress. Fish acclimated to temperatures ≥20°C exhibited elevated levels of plasma cortisol, muscle lactate, and plasma glucose after exposure to the acute stressors. After 24 h of recovery, fish showed longer metabolic recovery times at 15 and 20°C and cortisol levels remaining elevated at temperatures ≥20°C. Our findings suggest that brook trout may have a limited ability to acclimate to temperatures >20°C and increases in temperatures beyond 20°C may impact brook trout populations.

Biological Activity of Phytoestrogens

1965 ◽  
Vol 20 (7) ◽  
pp. 686-688 ◽  
Author(s):  
M. I. Elghamry
Keyword(s):  
Biological Activity ◽  
Epithelial Cell ◽  
Linear Relationship ◽  
Subcutaneous Administration ◽  
Thyroid Activity ◽  
Cell Height ◽  
Ovariectomized Mice ◽  
Thyroid Glands ◽  
Thyroid Uptake ◽  
Stimulation Of

Subcutaneous administration of β-sitosterol, isolated from Glycyrrhiza glabra, into ovariectomized mice induced: —1) An increase in the epithelial cell height of the thyroid vesicles, as well as a decrease in the surface area of the vesicular colloid when both were compared with the ovariectomized controls.2) A stimulation of iodine uptake by the thyroid glands of treated animals. Phytoestrogen treatment showed no linear relationship between the dosage of β-sitosterol and the thyroid uptake of I131.3) A rise in the level of thyroid and thyrotrophic hormones in the blood of mice injected with β-sitosterol. This increase in hormone levels parallels the thyroid activity.

Effects of partial exposure to lethal temperature on heterogeneously acclimated fish

1973 ◽  
Vol 51 (12) ◽  
pp. 1249-1255
Author(s):  
Fahmy K. Fahmy
Keyword(s):  
Brook Trout ◽  
Whole Body ◽  
Acclimation Temperature ◽  
Lethal Temperature ◽  
Tail Region ◽  
Mean Body Temperature ◽  
Individual Level ◽  
Time To Death ◽  
Different Temperatures ◽  
The One

Brook trout were acclimated either homogeneously, by exposing the whole body to the same temperature, or heterogeneously, by exposing the head and tail concurrently to two different temperatures in a divided chamber. After acclimation, one end of the fish was exposed to a lethal temperature (27.5C) while the other end was subjected to either 10 or 20C. The lethal response of any region of the fish varies with the acclimation temperature. For a heterogeneously acclimated fish, the cold-acclimated region when exposed to the lethal temperature reflected a mean body temperature effect, but when the warm-acclimated region was the one exposed, the time to death almost coincided with that of a fish wholly warm-acclimated and similarly exposed to the lethal temperature. When the head was exposed, death took place more rapidly when the tail region was at 20C than when it was at 10C. When the tail was exposed, death was slower when the head was at 20C than when it was at 10C. It is suggested that the tissue exposed responds according to its individual level of thermal acclimation.

A Comparative Study of Anadromous and Freshwater Populations of Brook Trout (Salvelinus fontinalis (Mitchill))

1952 ◽  
Vol 9 (4) ◽  
pp. 169-203 ◽  
Author(s):  
D. G. Wilder
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Sea Water ◽  
Feeding Habits ◽  
Flesh Colour ◽  
Body Form ◽  
Sea Trout ◽  
Length Relationship ◽  
Sexual Characteristics ◽  
Different Temperatures

Anadromous and freshwater populations of Salvelinus fontinalis have been compared to determine the taxonomic relationship of the sea trout and brook trout. Sea trout and freshwater trout differ seasonally in coloration and flesh colour but these differences appear to be environmental in origin rather than hereditary. Freshwater trout reared to hatching at 5.5 °C. had larger head parts, deeper and wider bodies, longer fins, more pectoral rays, dorsal rays, and branchiostegals but fewer scale rows and anal rays than those of common parentage reared at 0.9 °C. Sea trout and freshwater trout from the same river differ less in body form than trout of common parentage reared at different temperatures and less than four populations of freshwater trout. Differential development of the secondary sexual characteristics accounts for most of the differences in body form between sea and freshwater trout. Sea trout and freshwater trout from different rivers reared under the same conditions differed less in body form than any of the other populations compared. Sea and freshwater trout did not differ significantly in any of the meristic structures counted. Seasonal differences in weight-length relationship related to spawning and feeding habits were observed. Sea trout grow rapidly during the year in which they first migrate to the sea but subsequent growth is not appreciably faster than freshwater trout from the same river. Exposure of freshwater trout to sea water indicates that some could survive typical sea trout migrations. No evidence was obtained to indicate hereditary differences in migratory behaviour. Evidence available indicates that sea and freshwater trout of Moser River, Nova Scotia, constitute one taxonomic unit.

scholarly journals Determination of Load-Carrying Capacity of C-Profile Glued Ti-Al Column under Temperature Environment

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3013
Author(s):  
Leszek Czechowski
Keyword(s):  
Carrying Capacity ◽  
Tensile Tests ◽  
Discrete Models ◽  
Image Correlation ◽  
Load Carrying Capacity ◽  
Lagrange Equations ◽  
Load Carrying ◽  
Different Temperatures ◽  
Influence Of Temperature On

The paper deals with an examination of the behaviour of glued Ti-Al column under compression at elevated temperature. The tests of compressed columns with initial load were performed at different temperatures to obtain their characteristics and the load-carrying capacity. The deformations of columns during tests were registered by employing non-contact Digital Image Correlation Aramis® System. The numerical computations based on finite element method by using two different discrete models were carried out to validate the empirical results. To solve the problems, true stress-logarithmic strain curves of one-directional tensile tests dependent on temperature both for considered metals and glue were implemented to software. Numerical estimations based on Green–Lagrange equations for large deflections and strains were conducted. The paper reveals the influence of temperature on the behaviour of compressed C-profile Ti-Al columns. It was verified how the load-carrying capacity of glued bi-metal column decreases with an increase in the temperature increment. The achieved maximum loads at temperature 200 °C dropped by 2.5 times related to maximum loads at ambient temperature.

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