Urine Formation by the Malpighian Tubules of Calliphora
نویسنده
چکیده
Urine formation by the Malpighian tubules of insects depends on an active transport of potassium (Ramsay, 1953, 1955; Berridge, 1967, 1968). However, potassium transport alone will not induce water transport unless it is accompanied by an anion. For example, if the chloride bathing the isolated tubules of Calliphora is replaced with a non-transportable anion such as sulphate, fluid transport ceases. The mechanism of transporting anions to accompany the active secretion of potassium has been investigated.
منابع مشابه
The action of the excretory apparatus of Calliphora vomitoria in handling injected sugar solution.
Recent evidence suggests that the isolated Malpighian tubules of Calliphora possess mechanisms which restrict the loss of glucose and trehalose from the insect. This report establishes that the intact, diuresing fly does not excrete glucose or trehalose when solutions of these sugars are injected. When solutions of non-metabolized sugars such as sorbose and xylose are injected into the fly, the...
متن کاملUrine formation by the malpighian tubules of Calliphora. II. Anions.
The current concept of fluid transport in vertebrates is that water moves passively down the osmotic gradient created by an active transport of solute. Earlier suggestions that these tissues could transport water in the absence of a concomitant movement of solute have been rejected (Curran, 1965; Diamond, 1965; Robinson, 1965, 1966). Interest is now focused on the mechanism by which water movem...
متن کاملThe removal of sulphate by the excretory apparatus of the blowfly Calliphora vomitoria.
The excretion of sulphate by the isolated Malpighian tubules of Calliphora vomitoria has been investigated. Contrary to expectation, it was found that the isolated tubules are freely permeable to sulphate. The rate of sulphate secretion is comparable to the rates of secretion of both phosphate and chloride. The excretion of sulphate by the intact fly has also been verified.
متن کاملThe antidiuretic neurohormone RhoprCAPA-2 downregulates fluid transport across the anterior midgut in the blood-feeding insect Rhodnius prolixus.
Osmotic balance in insects is regulated by the excretory system, consisting of Malpighian tubules and the gut under the control of diuretic and antidiuretic factors. Terrestrial insects must conserve water, and antidiuresis is the norm, only interrupted by brief diuretic periods. Surprisingly, little is known about antidiuresis in insects. Two antidiuretic strategies have been described. The fi...
متن کاملMalpighian tubules of Rhodnius prolixus and Drosophila melanogaster. Secretion rates of Rhodnius tubules in amino-acid-free saline increase after addition of serotonin
contains a total concentration of amino acids 50–100 times that which is normal for mammalian plasma (Wigglesworth, 1972). Total haemolymph amino acid concentrations vary from 16 mmol l–1 in aquatic midges (Chironomus tentans; Firling, 1977) to 33 mmol l–1 in black flies (Simulium venustum; Gordon and Bailey, 1974), 54 mmol l–1 in blow flies (Calliphora vicina; Evans and Crossley, 1974), 90 mmo...
متن کامل