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|Title:||Circulatory Conservation of Anionic Antifreeze Peptides in the Glomerular Winter Flounder (Pseudopleuronectes Americanus)|
|Author(s):||Petzel, David Henry|
|Department / Program:||Physiology and Biophysics|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Biology, Animal Physiology|
|Abstract:||Physiological and morphological evidence presented in this report strongly argue that the anionic antifreeze peptides of the winter flounder are conserved in the circulation because they are repelled from anionic sites located in the walls of the glomerular capillaries of the winter flounder kidney.
The observations that are consistent with this charge to charge repulsion mechanism are the following: (1) Evidence from both physical and radioisotopic measurements of the anionic antifreeze peptides reveals that the antifreeze peptides are not present in the bladder urine. This lack of antifreeze activity is remarkable given the high serum concentrations of the antifreeze (four percent) and the fact that polyethylene glycol, of similar molecular weight, but neutral charge, is freely filtered at the glomerulus. (2) The fractional clearance of the anionic antifreeze peptides relative to polyethylene glycol is 0.02. (3) The fractional clearance of a cationic derivative of the peptides is eight times greater than that of the anionic antifreeze peptides. This increase in clearance, which is a result of the lack of repulsion of the peptide from the glomerular capillary wall, is consistent with similar findings in the rat using anionic, neutral and cationic derivatives of horseradish peroxidase and albumin. (4) In support of the above clearance studies it has been shown that the clearance of polyethylene glycol in pauciglomerular fishes possessing antifreeze is similar in magnitude to that of the clearance of the anionic antifreeze peptides in the winter flounder. (5) To preclude the possibility of reabsorption of the antifreeze, renal accumulation of the antifreeze in the kidney was looked for, but was not found. (6) Finally, morphological observations of winter flounder kidney tissue with the scanning electron microscope confirmed that the flounder do indeed possess glomeruli. Binding of cationized ferritin as viewed with the aid of transmission electron microscopy indicate the presence of anionic sites spaced about 65-85 nm apart in the lamina rara interna of the glomerular capillary wall.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982.
|Date Available in IDEALS:||2014-12-16|
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Dissertations and Theses - Molecular and Integrative Physiology
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois