Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 80-88).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 185-199).

Thesis (M.A.)--Oregon State University, 1987. / Typescript (photocopy). Includes bibliographical references (leaves 178-193). Also available online.

Young sockeye salmon (Oncorhynchus nerka) may occupy the epilimnion, thermocline or hypolimnion during lacustrine residence and may make extensive vertical migrations. Residence and migration over a range of pressure presents fish with certain physiological problems. Sockeye salmon meet these problems by adaptation, compromise and fortuity. Sockeye evidenced a tolerance to pressure in excess of 20 atmospheres, equivalent to a depth of water of 680 feet. Sockeye fry showed no behavioral response to pressure prior to initial filling of the swimbladder, but thereafter pressure induced compensatory swimming. Young sockeye proved to be dependent on atmospheric air for inflation of the swimbladder. The restrictions to vertical movement imposed by the swimbladder are minimized in sockeye by a relatively small bladder volume, little excess pressure within the bladder, the bladder being thin-walled and extensible and the inability of these fish to secrete gas into the bladder. When frightened, young sockeye sounded and expelled gas from the swimbladder. Gas expulsion was found to be under adrenergic control and retention of gas in the swimbladder under cholinergic control. During decompression with upward movement through thermally stratified water, gas disease or the "bends" is obviated by the rapid clearance of dissolved nitrogen from the blood stream. Young sockeye showed a tolerance to rapid decompression except under conditions permitting swimbladder gas to appear as emboli in the blood stream. / Science, Faculty of / Zoology, Department of / Graduate

Comparative histological and radiochemical studies of iodine metabolism in juvenile Oncorhynchus revealed good agreement between thyroid epithelial height and ability to convert I¹³¹ into protein-bound I¹³¹(PBI¹³¹). The ratio of I¹³¹ to PBl¹³¹ in plasma samples (Conversion Ratio) was considered superior to other thyroid assays reviewed. Peaks in thyroid activity and loss of I¹³¹ from the body occurred in sockeye and coho at the time of downstream migration, but in chum and pink only when postmigrants were retained in fresh water. In coho and sockeye these changes were transitory, in chum irreversible and in pink prolonged. On the above basis, thyroxine was assigned no specific role but a theory of smolt evolution was proposed and related to a phylogeny within the genus Oncorhynchus. / Science, Faculty of / Zoology, Department of / Graduate

Food study based on the stomach content analyses of spring and coho salmon collected from various localities along the southern British Columbia coast during the summer of 1957 revealed that herring followed by Crustacea formed the most important item of the diet of the two species. Coho salmon exhibited more pelagic and varied diet than spring salmon caught in the same area. Definite seasonal fluctuations in the composition of food and feeding intensity were noticed, considerable amounts of Crustacea were taken in early summer months and after that fish assumed importance. July and August mark the period when the feeding activity is intense in both the species. Qualitative and quantitative differences in the feeding conditions on the east and west coasts of Vancouver Island warrant the establishment of two food type areas. The differences in growth of fish on the two coasts as related to feeding conditions are discussed. Although, herring is the major food item of both spring and coho salmon, evidences are presented in support of the hypothesis that a reduction in herring stock abundance due to predation would not affect salmon catches. Based on ova measurements and maturity index values fish have been classified into immature and maturing. It appears that almost all coho salmon available to the commercial fishery are maturing, spring catches on the other hand include large percentage of both immature and maturing fish. Immature and maturing female springs divide at a fork length of 74 cm., cohos do so at an approximate fork length of 52 A volume method for the determination of egg numbers present in the ovary has been developed, the average percentage error between the calculated and actual counts being 5.3. it was found that the absolute fecundity is positively correlated to fish length and negatively to egg size but the magnitude of the effect of fish length on absolute fecundity is about four times greater than that of egg size. / Science, Faculty of / Zoology, Department of / Graduate

The effects of temperatures within the optimal range for incubation of salmon, and hyperoxic and hypoxic oxygen tensions, were examined to develop an optimal path of growth during the pre- rearing stage for chum salmon (Oncorhynchus keta). During early development, and at constant oxygen tension, an elevated temperature of 55°F (12.8°C) led to accelerated growth and most efficient conversion of yolk compared to 50°F (10°C) or 45°F (7.2°C). With increased age, growth and efficiency were favored by decreasing temperature with its associated increase in oxygen concentration and reduced metabolic demand by the embryo. After hatching, the detrimental effect of a high temperature was not offset by the increased availability of oxygen and growth was retarded relative to lower temperatures. Oxygen tensions within the treatment range of 145 to 253 mm Hg did not contribute significantly to embryo weight when measured at equal stages of development in day-degrees. The optimal path for growth with minimal mortality involved a gradual reduction in temperature from 55° to 45°F during incubation, a constant temperature of 45°F after hatching to the beginning of active feeding, and an oxygen tension not in excess of air saturation. / Science, Faculty of / Zoology, Department of / Graduate

This study was undertaken to determine whether the gonads of pink salmon (Oncorhynchus gorbuscha), could be stimulated with exogenous hormones to reproductive maturity one year earlier than normal. This procedure, if successful, could be used as a method for repopulating ‘off’ year cycles of pink salmon in numerous rivers in British Columbia and Washington. In the juvenile males, complete sexual maturity was attained by September in the year of hatching with thrice-weekly treatments of 10.0 micrograms and of 1.0 micrograms salmon (Oncorhynchus tshawytscha) gonadotropin per gram body weight. Histological examination of the precociously mature testes, and comparison with testes from uninjected controls repealed that the time of onset of the mitotic division of spermatogonia to form the primary spermatocyte, and the process of active spermatogenesis were accelerated. At sexual maturity, a scattering of localizations of ∆5-3ß hydroxysteroid dehydrogenase activity was observed which corresponded to the distribution of the interstitial cells. A larger stock of pink salmon, in which injections were initiated 83 days later, developed mature testes in the same time interval as the normal-sized individuals. These gonads were four times larger, however. A small species difference in the action of the gonadotropin preparation was found when comparing its effect on the G.S.I., rate of induction of sexual maturity, and 3ß-ol dehydrogenase activity of immature Oncorhynchus tshawytscha. In the females, the yolk stage was induced first in fish treated three times a week with 1.0 µg/gram body weight salmon gonadotropin and 1.5 µg/gram body weight estradiol 17ß for 126 days. Oocytes containing yolk globules did not appear in pink salmon treated with 1.0 µg/gram body weight salmon gonadotropin alone for a further 42 days. Estradiol l7ß alone, or in combination with salmon gonadotropin at a dosage of 15 µg/gram body weight inhibited vitellogenesis. Formation of oocytes 2 mm in diameter required seven and one half months of treatment with 1.0 µg/gram body weight salmon gonadotropin and 1.5 µg/gram body weight estradiol 17ß, and nine months of injections with l.0µg/gram body weight salmon gonadotropin alone. Few large yolky oocytes were developed by any of the treatments. Large numbers of pre-ovulatory corpora atretica were observed in all of the treated fish. Little histochemically demonstrable ∆5-3ß hydroxysteroid dehydrogenase activity was present in ovaries from pink or spring salmon juveniles treated for 3 months with various dosages of salmon gonadotropin. The significance of the results in relation to the original problem are discussed. / Science, Faculty of / Zoology, Department of / Graduate

Although the first preparations of the hypocalcemic hormone, calcitonin (ct), were extracted from rat thyroid glands, histological evidence showed that the "c" cells which produce the hormone are not restricted to this gland, but also occur in the parathyroid and thymus tissues of mammals. These cells arise embryologically from the last branchial pouch and in non-mammals they form a separate ultimobranchial gland which also contains hypocalcemic activity. The work described in this thesis provides evidence that this activity results from polypeptides structurally similar to those isolateo from mammalian thyroid tissues and.explores the relationship between the structural and functional differences of the two types of ct. A survey of four mammalian thyroid tissues (human, bovine, porcine and murine) ano four non-mammalian ultimo-branchial tissues (turkey, chicken, salmon and dogfish) demonstrated that these tissues contained hypocalcemic polypeptides with molecular weights of about 4000 as determined by gel filtration. When extracts were prepared using an organic solvent mixture developed for the thyroid ct' s the ultimobranchial tissues yielded more hypocalcemic activity on a fresh weight basis and the final product had a higher specific activity. Salmon ultimobranchal tissue was collected on a large scale and extracted to provide material for chemical characterization. A series of three gel filtration stages on sephaoex g-50 alternating with two ion-exchange chromatography stages on se-sephadex c-25 at two ph's provided a 300,000 fold purification and yielded 15 mg of pure salmon ct. amino acid analysis and partial characterization of tryptic peptides indicated that the ultimobranchial hormone was a 32 amino acio polypeptide with a disulfide bridge at the c-terminus. Although these features are also common to all the mammalian ct's, there are a number of unique features in the salmon ct structure. These structural differences were also reflected in the biological activity of the hormone. Salmon ct was nearly 50 times more active than human ct in the standard bioassay and the response to the salmon hormone was prolonged. Tests in plasma both in vivo and in vitro indicated that salmon ct was much more stable than the 'thyroid ct' s suggesting a possible reason for its greater potency. A survey of cohn fractions from human plasma showed that fractions iii-o, iv-1 iv-4 contained enzymes capable of rapidly degrading porcine ct. in further studies on fraction iv—1 a selective "calci-toninase" was purified by chromatography on deae-sephadex, sephadex g-200 and cm-sephadex. this enzyme rapidly inactivated porcine ct, but had no significant effect on salmon or human ct. synthetic porcine ct was digested with the enzyme and the resultant peptides were isolateo and identified. The nature of these peptides indicated that the enzyme was a peptidase with a specificity for the carboxyl side of arginine residues. similar digestions of pure native salmon ct produced no peptides providing at least a partial explanation for the greater stability of this hormone. These experiments also showed that the enzyme would not split at all arginine residues and would not cleave bonds associated with other basic residues. The data indicated that the enzyme had a molecular weight of about 30,000 and probably was derived from a precursor with a molecular weight of about 100,000. Tests of the action of the enzyme on fibrinogen showed that it was not thrombin. comparison of available data with that for other plasma enzymes indicated similarities to the kallikrein family of enzymes, but the "calcitoninase" does not appear to be identical with any of the well studies members of this group. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate