by Scott P. Kelly. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 378-410). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

Thesis (Ph. D.)--University of Michigan, 1927. / Thesis note on label mounted on p. 57. "Reprinted from the American Naturalist, vol. LX, January-February, 1926." "Literature cited": p. 77-81.

The present study provided information for the role of the RAS in seabream osmoregulatory responses. The structure of angiotensinogen suggested that flounder type Ang II was the prevalent form in seabream. However, HPLC analysis suggested that different forms of angiotensins were present in seabream adapted to different salinities. The status of RAS was revealed in seabream adapted to different salinities and a higher status was found in hypersaline environment. Local renal RAS was identified and it may be activated in hyposmotic media and associated with an increase in glomerular and tubular function to excrete excess water. In general, the RAS in seabream displays differential status, both at systemic and local levels, which modulates osmoregulatory functions under acute and chronic salinity perturbation. / The renin angiotensin system (RAS) is involved in the control of body fluid homeostasis in silver seabream. Seabream angiotensinogen was cloned and sequenced in the present study. The sequence alignment showed that the angiotensinogen of seabream is most similar to that of pufferfish. Differential status of RAS was found among different salinities, with relatively higher RAS activity among hyperosmotic adapted seabream. Circulating angiotensin II (Ang II) was higher in hyperosmotic adapted seabream, with the highest value observed in seabream adapted to double-strength seawater. Although the level of immunoreactive angiotensins in freshwater adapted seabream was higher than that of brackish-water, Ang III, but not Ang II, was the prevalent circulating form in freshwater adapted seabream according to HPLC analysis. Hepatic angiotensinogen expression, however, did not show any statistical difference among different salinities. A positive feedback control for angiotensinogen by Ang II is present in the hepatic tissue of seabream as Ang II increased the expression of angiotensinogen in isolated hepatocyte but captopril lowered the angiotensinogen expression in intact fish. Branchial Na-K-ATPase activities were elevated by Ang II and the activities among different salinities showed a pattern similar to that of circulating angiotensins. However, upon abrupt hyposmotic transfer, branchial Na-K-ATPase elevated along with a decrease in circulating Ang II, an observation implying that the relationship between Na-K-ATPase and Ang II may only be causal. Captopril blockade not only lowered not only circulating Ang II levels but also that of cortisol, indicating RAS activity may limit cortisol secretion. An elevation in the circulating cortisol may be related to the increase in branchial Na-K-ATPase activities after abrupt hyposmotic transfer. The stimulatory effect on branchial Na-K-ATPase activity and the vasopressor effect of Ang II were more potent in hyposmotic than hyperosmotic adapted seabream, which indicates hyposmotic adapted seabream is more sensitive to RAS activation. The renal RAS in silver seabream functions independently from the systemic RAS as the pattern of renal angiotensins was dissimilar to that of systemic angiotensins. The renal RAS was activated in brackish water conditions and abrupt hyposmotic transfer significantly increased renal RAS activities. Kidney morphometrics also indicated that hyposmotic adaptation increase the filtering capacity of seabream nephrons. The number and diameter of glomeruli increase significantly in freshwater adapted seabream, which may vastly increase the filtering surface of the nephrons. Collecting tubules were more prevalent in the kidney of hyposmotic adapted seabream, with higher number, diameter and thickness, suggesting a lower water permeability of collecting tubules is essential for the formation of copious and diluted urine in hyposmotic environment. / Wong Kwok Shing. / "December 2005." / Adviser: Norman Y. S. Woo. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6144. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 130-145). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis (Ph. D.)--Illinois State University, 1999. / Title from title page screen, viewed July 24, 2006. Dissertation Committee: Steven A. Juliano (chair), Wayne A. Riddle, Scott K. Sakaluk, Charles F. Thompson, Douglas W. Whitman. Includes bibliographical references (leaves 126-133) and abstract. Also available in print.

Luk Chun-yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 119-131). / Abstracts in English and Chinese. / ABSTRACT --- p.i / ACKNOWLEDGEMENTS --- p.iv / LIST OF FIGURES --- p.x / LIST OF TABLES --- p.xii / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1 / Chapter CHAPTER 2 --- LITERATURE REVIEW --- p.6 / Chapter 2.1 --- Introduction --- p.7 / Chapter 2.2 --- Ammonia chemistry --- p.10 / Chapter 2.3 --- Ammonia metabolism and excretion --- p.11 / Chapter 2.3.1 --- Ammonia production --- p.11 / Chapter 2.3.2 --- Blood levels of ammonia --- p.12 / Chapter 2.3.3 --- Ammonia Excretion --- p.17 / Chapter 2.4 --- Urea metabolism and excretion --- p.23 / Chapter 2.4.1 --- Urea Chemistry --- p.23 / Chapter 2.4.2 --- Urea production in fishes --- p.24 / Chapter 2.4.3 --- Argininolysis --- p.25 / Chapter 2.4.4 --- Uricolysis --- p.26 / Chapter 2.4.5 --- Ornithine-urea Cycle (OUC) --- p.28 / Chapter 2.4.5.1 --- Tilapia inhabiting the highly alkaline Lake Magadi --- p.32 / Chapter 2.4.5.2 --- High Ambient Ammonia --- p.33 / Chapter 2.4.5.3 --- Air Exposure --- p.34 / Chapter 2.4.5.4 --- Toadfishes --- p.34 / Chapter 2.4.6 --- Blood urea concentration --- p.35 / Chapter 2.4.7 --- Urea excretion in fishes --- p.37 / Chapter 2.4.7.1 --- Branchial urea excretion in fishes --- p.37 / Chapter 2.4.7.2 --- Mechanisms of renal excretion in fishes --- p.40 / Chapter 2.5 --- Influence of environmental salinity on nitrogen excretion in teleosts --- p.42 / Chapter CHAPTER 3 --- BODY COMPOSITION AND UREA BIOSYNTHESIS OF SPAR US SARBA IN DIFFERENT SALINITIES --- p.46 / Chapter 3.1 --- Introduction --- p.47 / Chapter 3.2 --- Materials and Methods --- p.49 / Chapter 3.2.1 --- Experimental animals --- p.49 / Chapter 3.2.2 --- Tissue sampling --- p.49 / Chapter 3.2.3 --- Water chemistry analysis --- p.50 / Chapter 3.2.4 --- Hematological parameters --- p.50 / Chapter 3.2.5 --- Metabolite and electrolyte contents --- p.51 / Chapter 3.2.6 --- Hepatic enzymes activities --- p.51 / Chapter 3.2.6.1 --- Tissue preparation --- p.51 / Chapter 3.2.6.2 --- Carbamyl phosphate synthetases (CPSases; E.C. 2.7.2.5) --- p.52 / Chapter 3.2.6.3 --- Ornithine carbamoyl transferase (OCTase; E.C. 2.1.3.3) --- p.53 / Chapter 3.2.6.4 --- Argininosuccinate synthetase (ASS; E.C. 6.3.4.5) --- p.54 / Chapter 3.2.6.5 --- Argininosuccinate lyase (ASL; E.C. 4.3.2.1) --- p.54 / Chapter 3.2.6.6 --- Arginase (ARG; 3.5.3.1) --- p.55 / Chapter 3.2.6.7 --- Glutamate dehydrogenase (EC 1.4.1.3) --- p.55 / Chapter 3.2.6.8 --- Uricase (E.C. 1.7.3.3) --- p.56 / Chapter 3.2.6.9 --- Allantoinase --- p.57 / Chapter 3.2.6.10 --- Allantoicase --- p.57 / Chapter 3.2.7 --- Statistical analysis --- p.58 / Chapter 3.3 --- Results --- p.59 / Chapter 3.3.1 --- "Changes in hepatosmatic index, renal somatic index, muscle water and lipid content and hematological parametersin response to different salinity acclimation" --- p.59 / Chapter 3.3.2 --- Changes in serum chemistry in response to different salinity acclimation --- p.60 / Chapter 3.3.3 --- Changes in hepatic ornithine-urea cycle enzyme activitiesin response to different salinity acclimation --- p.61 / Chapter 3.3.4 --- Changes in GDHase and uricolytic enzyme activitiesin response to different salinity acclimation --- p.62 / Chapter 3.4 --- Discussion --- p.71 / Chapter 3.4.1 --- Hematological responses --- p.72 / Chapter 3.4.2 --- Muscle moisture content --- p.74 / Chapter 3.4.3 --- Circulating electrolyte levels --- p.75 / Chapter 3.4.4 --- Circulating metabolites levels --- p.77 / Chapter 3.4.5 --- Urea metabolism --- p.80 / Chapter 3.4.5.1 --- Ornithine-urea cycle enzymes --- p.80 / Chapter 3.4.5.2 --- Carbamoyl phosphate synthetase isozymes --- p.81 / Chapter 3.4.5.3 --- Uricolytic pathway and argininolysis --- p.85 / Chapter 3.4.5.4 --- Influence of salinity on urea metabolism --- p.86 / Chapter 3.4.6 --- Conclusion --- p.87 / Chapter CHAPTER 4 --- EFFECT OF SALINITY ON NITROGEN EXCRETION OF SPARUS SARBA --- p.88 / Chapter 4.1 --- Introduction --- p.89 / Chapter 4.2 --- Materials and Methods --- p.91 / Chapter 4.2.1 --- Experimental animals --- p.91 / Chapter 4.2.2 --- Experimental protocol --- p.92 / Chapter 4.2.3 --- Determination of net ammonia and urea excretion rates --- p.94 / Chapter 4.2.4 --- Statistical analysis --- p.94 / Chapter 4.3 --- Results --- p.95 / Chapter 4.3.1 --- Net ammonia-N and urea-N excretion rates --- p.95 / Chapter 4.3.2 --- Changes in net ammonia-N and urea-N excretion ratesin response to abrupt hyposmotic exposure --- p.95 / Chapter 4.3.3 --- Changes in net ammonia-N and urea-N excretion rates after exposure to amiloride for 3 hours --- p.96 / Chapter 4.3.4 --- Changes in net urea-N excretion rates in response to elevated body urea levels --- p.96 / Chapter 4.3.5 --- Changes in net ammonia-N excretion rates in response to elevated body ammonia levels --- p.97 / Chapter 4.4 --- Discussion --- p.106 / Chapter 4.4.1 --- Influence of environmental salinity on net ammonia-N and urea-N excretion rates --- p.106 / Chapter 4.4.2 --- Effects of amiloride on nitrogen excretion --- p.109 / Chapter 4.4.3 --- Effect of increased body ammonia on ammonia excretion --- p.113 / Chapter 4.4.4 --- Changes in net urea-N excretion rates in response to elevated body urea levels --- p.113 / Chapter 4.5 --- Conclusion --- p.114 / Chapter CHAPTER 5 --- GENERAL CONCLUSION --- p.115 / references --- p.119

Fung Chun Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 117-139). / Abstracts in English and Chinese. / Declaration of Originality --- p.i / Acknowledgements --- p.ii / Abstract --- p.iii / 摘要 --- p.v / List of figures --- p.vi / List of tables --- p.viii / List of abbreviations --- p.ix / Chapter Chapter I --- General introduction --- p.1 / Chapter 1.1 --- Different fish habitats with various salinities --- p.1 / Chapter 1.2 --- Osmotic challenges faced by teleosts --- p.2 / Chapter 1.3 --- High ionic strength results in DNA damage and excess water gain --- p.3 / Chapter 1.4 --- Osmoregulatory organs and mechanisms for osmotic balance --- p.4 / Chapter 1.5 --- Different tolerance to salinity changes --- p.8 / Chapter 1.6 --- Effective communication among osmoregulatory organs --- p.9 / Chapter 1.7 --- Introduction to GH and PRL --- p.9 / Chapter 1.8 --- Structure of the GHR and PRLR --- p.10 / Chapter 1.9 --- Hypoosmoregulatory action of GH/IGF-I axis in teleosts --- p.11 / Chapter 1.10 --- Hyperosmoregulatory action of PRL in teleosts --- p.11 / Chapter Chapter II --- Research rationale --- p.13 / Chapter 2.1 --- Physiological importance of osmoregulation in fish --- p.13 / Chapter 2.1.1 --- Energy metabolism --- p.13 / Chapter 2.1.2 --- Growth --- p.14 / Chapter 2.1.3 --- Immunity --- p.14 / Chapter 2.1.4 --- Reproduction --- p.15 / Chapter 2.2 --- Aquaculture importance --- p.15 / Chapter 2.3 --- Unknown molecular regulatory mechanism of hormones during salinity changes in fish --- p.16 / Chapter 2.4 --- Animal model --- p.17 / Chapter Chapter III --- In vivo studies of sbGHR and sbPRLR expression in osmoregulatory organs in response to salinity changes --- p.18 / Chapter 3.1 --- Introduction --- p.18 / Chapter 3.1.1 --- Dynamic change of GH level during salinity changes --- p.18 / Chapter 3.1.2 --- Dynamic change of PRL level during salinity changes --- p.19 / Chapter 3.1.3 --- In vitro studies of GH and PRL release from teleost pituitary in response to extracellular osmolality changes --- p.20 / Chapter 3.1.4 --- Biological actions of GH and PRL through the GHR and PRLR --- p.21 / Chapter 3.2 --- Materials and methods --- p.23 / Chapter 3.3 --- Results --- p.28 / Chapter 3.4 --- Discussion --- p.36 / Chapter 3.4.1 --- Plasma osmolality change during salinity changes --- p.36 / Chapter 3.4.2 --- Gene expression after HSW exposure --- p.38 / Chapter 3.4.3 --- Ionic mediators of the gene expression --- p.43 / Chapter 3.4.4 --- Gene expression after BW exposure --- p.44 / Chapter 3.4.5 --- Dynamic changes of the GHR and PRLR in response to salinity changes --- p.45 / Chapter 3.4.6 --- Regulation of the gene expression in response to salinity changes --- p.46 / Chapter Chapter IV --- Gene expression of sbGHR in liver during salinity changes --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.1.1 --- Responses of the somatotropic axis to salinity changes in fish --- p.49 / Chapter 4.2 --- Materials and methods --- p.52 / Chapter 4.3 --- Results --- p.56 / Chapter 4.4 --- Discussion --- p.60 / Chapter 4.4.1 --- Inhibition of GHR and IGF-I gene expression in liver during HSW exposure --- p.60 / Chapter 4.4.2 --- Downregulation of GHR gene expression by hyperosmotic stress --- p.62 / Chapter 4.4.3 --- Growth retardation of fish during hyperosmotic environment --- p.64 / Chapter Chapter V --- Gene expression studies of sbPRLR in gill organ culture --- p.68 / Chapter 5.1 --- Introduction --- p.68 / Chapter 5.1.1 --- Functions of gill in fish osmoregulation --- p.68 / Chapter 5.1.2 --- Gill culture as a model for osmoregulation studies --- p.69 / Chapter 5.2 --- Materials and methods --- p.70 / Chapter 5.3 --- Results --- p.71 / Chapter 5.4 --- Discussion --- p.73 / Chapter Chapter VI --- Regulation of gene expression of sbGHR in liver during hyperosmotic stress: promoter studies --- p.75 / Chapter 6.1 --- Introduction --- p.75 / Chapter 6.1.1 --- What is a promoter? --- p.75 / Chapter 6.1.2 --- Promoter studies of GHR gene --- p.76 / Chapter 6.2 --- Materials and methods --- p.78 / Chapter 6.3 --- Results --- p.85 / Chapter 6.4 --- Discussion --- p.104 / Chapter Chapter VII --- General discussion and future perspectives --- p.111 / References --- p.117

Also, the branchial hsp70 levels in fish following chronic salinity acclimation and abrupt hypo-osmotic exposure to 6 ppt were assessed by Western blotting. Upon chronic salinity acclimation, the lowest branchial hsp70 level was found in fish cultured in an iso-osmotic salinity of 12 ppt and the highest was in 50 ppt and 6 ppt environments. Freshwater acclimation resulted in return to lower hsp70 level. The results indicated that iso-osmotic salinity would bring about the least stress level while 50 ppt and 6 ppt were the most stressful salinities to Sparus sarba as indicated by using hsp70 expression as a biomarker of stress. Compared to 50 ppt and 6 ppt, the stress level of fish in fresh water was lower. On the other hand, Sparus sarba exhibited a significant increase in branchial hsp70 level immediately after abrupt hypo-osmotic exposure to 6 ppt when compared with seawater fish sampled at the same time point and increased hsp70 level was sustained throughout the sampling period, indicating the exposure was stressful to the fish. / In the present study, pituitary and serum levels of prolactin in a marine teleost, Sparus sarba, chronically acclimated to various salinities: fresh water (0 ppt), hypo-osmotic (6 ppt), iso-osmotic (12 ppt), normal seawater (33 ppt) and hypersaline (50 ppt) or abruptly exposed to a hypo-osmotic environment of 6 ppt were quantified by the developed peptide-based indirect ELISAs. Progressive increases in pituitary and serum prolactin were found as chronic salinity acclimation progressed from seawater to fresh water. Also, prolactin secretion was immediately induced by abrupt hypo-osmotic exposure to 6 ppt and remained significantly elevated up to 5 days post-exposure to 6 ppt. The results underline the importance of prolactin in marine teleosts kept in fresh water or waters of low salinity. However, there was no significant difference in pituitary prolactin during the course of the abrupt hypo-osmotic exposure experiment. The results may indicate that prolactin might be secreted rapidly from pituitary in large quantities to cope with abrupt exposure to a low-salinity environment. / In the present study, the effects of pharmacological drugs on prolactin levels in pituitary and serum of Sparus sarba were investigated. An increase in prolactin synthesis and release but a decrease in branchial hsp70 expression were found after treatment with sulpiride, a DA-D2 receptor antagonist. In contrast, a reduction in prolactin levels in pituitary and serum but an elevation in hsp70 level in gill were observed following administration of bromocriptine, a DA-D2 receptor agonist. Since hsp70 expression indicates the stress levels, the results of these studies supported the notion that increased prolactin synthesis and release might be related to a reduced stress state and prolactin might have a protective effect on stress tolerance in fish. / Lastly, the role of prolactin in regulating apoptosis in Sparus sarba branchial cells was examined. Successful induction of apoptosis was indicated by an increase in the apoptotic parameter caspase-3 activity in primary cultures of Sparus sarba branchial cells treated with camptothecin, a specific inducer of apoptosis. In this study, prolactin was shown to be anti-apoptotic in Sparus sarba branchial cells as co-treatment with ovine prolactin (oPRL) and camptothecin has been observed to attenuate the elevated caspase-3 activity in gill cell primary cultures. Also, prolactin was found to protect the branchial cells from apoptosis by maintaining the hsp70 level in the cells treated with camptothecin. / The objectives of the present study were to investigate the roles of prolactin in salinity adaptation, hsp70 expression and apoptosis in silver sea bream (Spaurs sarba). Firstly, specific peptide-based indirect ELISAs were developed for pituitary and serum prolactin of Sparus sarba. These assays had been validated by parallelism between the dilution response curves using serially diluted pituitary homogenate and serum sample with the standard curves of the synthetic peptide derived from the amino acid sequence of black sea bream (Acanthopagrus schlegelii ) prolactin. / Ng, Ho Yuen Andus. / "September 2007." / Adviser: N. Y. S. Woo. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4567. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 143-189). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

All these findings can help us to elucidate the mechanisms for the fish to detect changing osmotic conditions and transform signals to osmoregulatory responses. / In the first part of the study, PRL and PRL-releasing peptide (PrRP) cDNAs have been isolated from euryhaline silver sea bream. The PRL cDNA consists of 1360 bp encoding 212 amino acids whereas the PrRP cDNA contains 631 bp encoding prepro-PrRP with 122 amino acids. PRL mRNA was uniquely expressed in sea bream pituitary but PrRP mRNA was expressed in a variety of tissues. Expression levels of both PRL and PrRP mRNA have been examined in sea bream adapted to different salinities (0, 6, 12, 33 and 50 ppt). In pituitary, both PRL and PrRP mRNA were synchronized in their expression, being significantly higher in fish adapted to low salinities (0 and 6 ppt), but the expression profile of hypothalamic PrRP in different salinities was different. These data suggested that PrRP may possibly act as a local modulator in pituitary rather than a hypothalamic factor for regulating pituitary PRL expression in silver sea bream. / In the second part of the study, silver sea bream abruptly transferred from 33 to 6 ppt exhibited a remarkable pituitary PRL secretion following closely with the temporal changes in serum osmolality and ion levels. In order to investigate the direct effect of extracellular osmolality to pituitary PRL secretion, sea bream pituitary cells were dispersed and exposed to a medium with reduced ion levels and osmolality. PRL released from pituitary cells was found to be significantly elevated. In hyposmotic exposed anterior pituitary cells, cell volume exhibited a 20% increase when exposed to a medium with a 20% decrease in osmolality. These enlarged pituitary cells did not shrink until the surrounding hyposmotic medium was replaced, a phenomenon suggesting an osmosensing ability of silver sea bream PRL cells for PRL secretion in response to a change in extracellular osmotic pressure. / In the third part, olfactory rosette in the nasal cavity was surgically removed from silver sea bream adapted to 6 ppt and 33 ppt and mRNA expression of PRL and PrRP in silver sea bream were measured. The elevated pituitary PRL and PrRP mRNA expression levels as seen in 6 ppt-adapted fish were abolished by this olfactory lamellectomy. On the other hand, hypothalamic PrRP mRNA expression in 6 ppt-adapted fish did not change but those in 33 ppt-adapted fish increase significantly after olfactory lamellectomy. These data suggest a possible osmosensing role of the olfactory system for regulation of PRL expression during hypo-osmotic acclimation of the fish. Besides, calcium-sensing receptor (CaSR) was cloned and its mRNA expression in olfactory system, as shown in other fish species previously, was investigated. However, no CaSR expression could be detected in olfactory rosette and nerve but its expression was demonstrated in osmoregulatory tissues and brain. There was no significant difference in CaSR mRNA expression in pituitary, kidney and anterior intestine of fish adapted to different salinities. These studies could not provide conclusive evidence to correlate CaSR with osmosensing in silver sea bream. / The present study used silver sea bream (Sparus sarba ) as a euryhaline fish model to investigate the regulation of prolactin (PRL) expression and secretion in fish adapted to different salinities. / Kwong, Ka Yee. / Adviser: Norman Y. S. Woo. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3248. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 154-184). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Branchial carbonic anhydrase was purified from silver seabream (Sparus sarba) and antibody against the enzyme was obtained by immunization in rabbits. An assay for quantifying the activity of carbonic anhydrase was developed. Using enzymatic and immunological techniques, the activity, expression and distribution of branchial carbonic anhydrase of silver seabream acclimated to different salinities were studied. Fish gill is one of the most important organs involved in various homeostatic processes. The ability of euryhaline fish to maintain constant internal ionic balance is crucial for the survival of the fish upon change in salinity. The presence of carbonic anhydrase in the chloride cells was suggested to be an important enzyme involved in ion regulation of fish. / In the present study, branchial carbonic anhydrase and erythrocyte carbonic anhydrase were purified from the gill cells of silver seabream with p-aminomethylbenzenesulfonamide-agarose affinity column. They were predominantly cytosolic with a molecular size of 26.6 k Da for branchial carbonic anhydrase and 28.6 k Da for erythrocyte carbonic anhydrase. Investigation of kinetic properties towards the inhibitor acetazolamide has helped determine the inhibition constants (Ki of branchial carbonic anhydrase: 0.54 x 10-9; Ki of erythrocyte carbonic anhydrase: 0.22 x 10-9). The difference in molecular size and inhibition constant towards acetazolamide supported the view that branchial carbonic anhydrase and erythrocyte carbonic anhydrase were two different isozymes. Polyclonal antibody specific to seabream branchial carbonic anhydrase was obtained by immunization in rabbit. The distribution of branchial carbonic anhydrase in the gill of seabream acclimated to different salinities was studied with immunohistochemical method. The enzyme was mainly located at the interlamellar region. The effect of salinity (0, 6, 12, 33, 50 and 70 ‰) acclimation on the expression and activities of branchial carbonic anhydrase has shown a U-shape pattern from freshwater to double-strength seawater on the quantity of seabream branchial carbonic anhydrase. Higher amount of branchial carbonic anhydrase in freshwater was consistent with the current view that the enzyme was actively involved in the ion uptake process through the hydration of carbon dioxide to produce bicarbonate ion and proton for the exchange of chloride and sodium ions, respectively. An interesting finding was obtained with elevated amount of branchial carbonic anhydrase in seabream acclimated to double-strength seawater and the possible role of the enzyme in such extreme environment was discussed. / This study has provided useful information on the properties, localizations and activities of branchial carbonic anhydrase in silver seabream for the understanding of the involvement of the enzyme in salinity adaptation of silver seabream. / Ma, Wing Chi Joyce. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3250. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 127-151). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Wong Kwok-Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 89-107). / Abstracts in English and Chinese. / Title --- p.i / Abstract (English) --- p.ii / Abstract (Chinese) --- p.v / Content --- p.vii / Acknowledgement --- p.x / Abbreviation --- p.xii / Lists of tables and figures --- p.xiii / Chapter Chapter 1 --- General introduction --- p.1 / Chapter Chapter 2 --- "Effects of salinity on the cardiovascular responses and dipsogenic behaviors and silver seabream, Sparus sarba." / Chapter 2.1 --- Literature review / Chapter 2.1.1 --- Teleost euryhalinity --- p.5 / Chapter 2.1.2 --- Salinity and blood respiratory properties --- p.7 / Chapter 2.1.3 --- Salinity and blood volume --- p.8 / Chapter 2.1.4 --- Salinity and blood pressure --- p.10 / Chapter 2.1.5 --- Intestine physiology --- p.12 / Chapter 2.1.6 --- Summary --- p.14 / Chapter 2.2 --- Materials and methods / Chapter 2.2.1 --- Experimental animals --- p.19 / Chapter 2.2.2 --- Salinity adaptation --- p.19 / Chapter 2.2.3 --- Drinking rate measurement --- p.19 / Chapter 2.2.4 --- Respiratory characteristics --- p.20 / Chapter 2.2.5 --- Blood volume measurement --- p.21 / Chapter 2.2.6 --- Blood pressure experiment --- p.23 / Chapter 2.2.7 --- Statistical analysis --- p.23 / Chapter 2.3 --- Results / Chapter 2.3.1 --- Drinking rate --- p.25 / Chapter 2.3.2 --- Oxygen dissociation curves --- p.27 / Chapter 2.3.3 --- Blood volume --- p.29 / Chapter 2.3.4 --- Blood pressure --- p.31 / Chapter 2.4 --- Discussion / Chapter 2.4.1 --- Drinking rate --- p.36 / Chapter 2.4.2 --- Oxygen dissociation curves --- p.37 / Chapter 2.4.3 --- Blood volume --- p.38 / Chapter 2.4.4 --- Blood pressure --- p.40 / Chapter Chapter 3 --- "Manipulation of renin-angiotensin system in relation to the cardiovascular responses and dipsogenic behaviors of silver seabream, Sparus sarba." / Chapter 3.1 --- Literature review / Chapter 3.1.1 --- Renin angiotensin system (RAS) --- p.41 / Chapter 3.1.2 --- RAS and blood pressure --- p.47 / Chapter 3.1.3 --- RAS and drinking --- p.53 / Chapter 3.1.4 --- RAS and Cortisol --- p.55 / Chapter 3.1.5 --- RAS and kidney --- p.58 / Chapter 3.1.6 --- Summary --- p.58 / Chapter 3.2 --- Materials and methods / Chapter 3.2.1 --- Experimental animals --- p.61 / Chapter 3.2.2 --- Salinity adaptation --- p.61 / Chapter 3.2.3 --- Drinking rate measurement --- p.61 / Chapter 3.2.4 --- Determination of angiotensin converting enzyme (ACE) activity --- p.61 / Chapter 3.2.5 --- Blood pressure experiment --- p.62 / Chapter 3.2.6 --- Statistical analysis --- p.63 / Chapter 3.3 --- Results / Chapter 3.3.1 --- Drinking rate --- p.64 / Chapter 3.3.2 --- ACE activity --- p.69 / Chapter 3.3.3 --- Blood pressure --- p.71 / Chapter 3.4 --- Discussion / Chapter 3.4.1 --- Drinking rate --- p.77 / Chapter 3.4.2 --- ACE activity --- p.81 / Chapter 3.4.3 --- Blood pressure --- p.83 / Chapter Chapter 4 --- General conclusion --- p.86 / Reference --- p.89