Oxygen consumption of tadpoles during metamorphosis

Uracil Metabolism in Tadpoles during Thyroxine-induced Metamorphosis.

Previous work in this laboratory (1) has shown that an increase in carbamyl phosphate synthetase activity in the livers of thyroxine-treated tadpoles is the result of protein synthesis de 1u)vo. This induction of the synthesis of a specific enzyme protein by thyroxine was found to be inhibited by chloramphenicol and thiouracil (2). A subsequent survey (3) of several purine and pyrimidine deriva...

Age factor in the induced metamorphosis of thyroidectomized tadpoles.

Three age-groups of thyroidectomized tadpoles of Rana catesbeiana were treated with a series of the same graded increasing concentrations of thyroxin. Normal froglets were formed from the three groups at the end of the induced metamorphosis. Growth and metamorphosis were compared. It was found that while the growth rate was a function of ageing, the pattern and rate of metamorphosis were not af...

Arrested development in Xenopus laevis tadpoles: how size constrains metamorphosis.

Xenopus laevis tadpoles that arrest development and remain as larvae for several years sometimes occur spontaneously in laboratory populations. These tadpoles cease development at an early hindlimb stage, but continue to grow and develop into grossly deformed giants. Giant tadpoles lack thyroid glands, and differ in morphology and behaviour from normal larvae. They are negatively buoyant, typic...

The Oxygen Consumption of Flies during Flight

Moderate dose of watercress and red radish does not reduce oxygen consumption during graded exhaustive exercise

Objective: Very recent studies have reported positive effects of dietary nitrate on the oxygen consumption during exercise. This research aimed to study the effect of moderate dose of high-nitrate vegetables, watercress (Nasturtium officinale) and red radish (Raphanus sativus) compared with a control group on the incremental treadmill exercise test following a standard Bruce protocol controlled...