Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES.

Não consta resumo na publicação. / Abstract not available.

Master of Science / Department of Animal Sciences and Industry / Robert D. Goodband / Michael D. Tokach / A total of 12,229 pigs were used in nine experiments to determine the effects of Na, Cl, and sodium metabisulfite-based feed additives on pig growth performance. Experiments 1, 2, and 3 were conducted to determine the effects of added dietary salt on growth performance of pigs weighing 7 to 10, 11 to 30, and 27 to 65 kg. The BLL models suggested the optimal dietary added salt concentration to maximize ADG for pigs weighing 7 to 10 and 11 to 30 kg was 0.59% (0.34% Na and 0.58% Cl) and 0.51% added salt (0.22% Na and 0.42% Cl), respectively. There was no evidence to indicate that growth of 27 to 65 kg pigs was improved beyond a 0.10% added salt inclusion (0.11% Na and 0.26% Cl). Experiments 4, 5, and 6 were conducted to determine the effects of source and concentration of Na and Cl on the growth performance of pigs weighing 7 to 12 kg. In Exp. 4, pigs fed an added salt diet that contains a Na and Cl concentration of 0.35% and 0.60% had greater growth performance compared to pigs fed a deficient Na concentration of 0.18%. In Exp. 5, pigs fed a Na concentration of 0.35%, regardless of ion source, had improved ADG compared to pigs fed a Na concentration of 0.13% or 0.57%. In Exp. 6, maximum ADG and G:F could be obtained with a Cl concentration of 0.38% based on the BLL and QP models. Experiments 7, 8, and 9 were conducted to evaluate the effects of Product 1 (Provimi, Brooksville, OH), Product 2 (Nutriquest, Mason City, IA), and sodium metabisulfite (SMB) on the growth performance of nursery pigs weighing approximately 6 to 25 kg. In Exp. 7, pigs fed Product 1 had higher ADG compared to pigs fed the control. In Exp. 8, pigs fed either Product 1 or 2 at the highest concentration and for the longest period of time had greater ADG compared to pigs fed the control diet. In Exp. 9, pigs fed SMB or Product 1 had greater ADG compared to pigs fed a lower concentration of SMB and the control.

I have investigated the evolutionary response of Pseudomonas aeruginosa to salt (NaCl) stress, and the physiological mechanisms responsible for this adaptation. Populations of P. aeruginosa founded from the same ancestral genotype were selected at three different concentrations of NaCl, low, moderate and high for about 660 generations with four independent replicates for each concentration. Adaptation was measured as the fitness of the evolved populations relative to the ancestor assessed in direct, head-to-head competition experiments conducted in the same environment in which they were selected (direct response) as well as in all alternative environments (correlated response). Results suggest that selection in each salt environment led to adaptation to that environment and a modest degree of specialization that evolved because correlated responses to selection were smaller than direct responses. In order to identify the physiological mechanisms contributing to the populations' adaptation in high NaCl concentration, I chose a sample of evolved lines that showed the strongest evidence for specialization to salt and competed them against the common ancestor in KCl and sucrose. Results suggested that increased Na+ /H+ antiporter activity is probably the primary mechanism behind adaptation to high NaCl concentration, however alternative mechanisms cannot be excluded. Tolerance curves, which measure the performance of a genotype across a gradient of salt concentrations, suggested no change in the high salt group’s ability to tolerate extreme concentrations of NaCl. We conclude that high salt evolved population showed improvements to its ionic/osmotic stress resistance strategies mainly to Na+ efflux strategies but with no changes to salt niche.

This experiment was aimed at the determination of the dipole moment of the diatomic molecule HC1⁺ (in the ²π½ state). The method was to observe the Stark splitting optically by using a 3.4 meter Jarrell ash spectrograph. The charged diatomic molecule was obtained by passing HCl gas through a LoSurdo discharge tube in which a high electric field was applied; optical plates were obtained from the spectrograph and analysed. Dipole moment of HC1⁺ in the ²π½ state was found to be smaller than 0.8 debye. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Isotope and dye estimates were made of body fluid compartment sizes in White Leghorn roosters, Glaucous-winged gulls, and in groups of Pekin ducks which were raised on either fresh water or regimes of hypertonic NaCl solution. The gulls and both groups of ducks were observed to have plasma (T-1824 dye) and total body water (H₂³O) volumes larger than thoseof the roosters, whereas the reverse was true for Br⁸² space (extracellular fluid; ECF) measurements. Salt fed ducks showed smaller, but insignificantly different compartment sizes (% body weights) when compared to fresh water raised ducks. The effects of an intravenous injection of hypertonic NaCl on the distribution of body water were compared among birds which differed in their capacity for renal and extra-renal salt elimination. In those birds (gulls, salt water ducks, and fresh water ducks with functional salt glands) which exhibited extra-renal salt secretion, the increase in ECF was significantly greater in response to the intravenous injection of hypertonic NaCl than in those birds (roosters and non-secreting fresh water ducks) which did not utilize the salt glands. The relative amounts and concentrations of the salt load removed by renal and extra-renal routes of elimination were compared. Birds with actively secreting nasal glands voided a major equivalent of the injected NaCl as solutions hypertonic to plasma NaCl levels. Renally eliminated NaCl represented a much smaller portion of the load and was in all cases hypo- or isotonic with plasma ion levels. Isotopically labelled Na²² CI administered concomitantly with the salt load in several of the test birds revealed that a large portion of the labelled sodium chloride was removed by the nasal glands and kidneys before there was equilibration of the injected load with extravascular compartments. A preliminary report is made on the composition and possible source of an excess eye secretion observed in the rearing of saline fed Pekin ducks. The enlarged Harderian glands of these birds were implicated as the source of a fluid several fold hyperkalemic to plasma ion concentrations. The secreted fluid was observed to accumulate and encrust the feathers below the inner canthus of the eye. / Science, Faculty of / Zoology, Department of / Graduate

The ATP-gated P2X7 receptors (P2X7Rs) play a key role in the release of pro-inflammatory cytokines in response to immunological challenges. Pannexin 1 (Panx1), conventionally described as a hemichannel forming protein, was suggested to be involved in the formation of the P2X7 large pore, which provides a conduit for large molecules such as fluorescent dyes. Firstly, this thesis demonstrated that the P2X7R-mediated dye uptake, a phenomenon attributed to the activation of Panx1, was suppressed by acidic pH and this inhibition was abolished in a P2X7 mutant (aspartic acid 197 to alanine) that was insensitive to extracellular pH. Then, the functional properties of human or mouse Panx1 in HEK293 cells were analysed in the absence of P2X7. The Panx1 currents were not affected by extracellular/intracellular calcium, but were reversibly inhibited by adenosine triphosphate (ATP) and non-specific anion channel blockers. Ion substitution experiments showed that Panx1 was permeable only to monovalent anions and single channel studies revealed a medium sized unitary conductance of Panx1 (~65 pS). Based on the evidence, this thesis concluded that Panx1 is an anion channel but not a hemichannel as originally proposed.

The cellular mechanism and regulation of KC1 reabsorption across the rectum of the desert locust Schistocerca gregaria has been studied using tracer fluxes, ion-sensitive microelectrodes, and electrophysiological techniques. Serosal addition of 1 mM cAMP stimulates transepithelial short- circuit current (I[sub=SC]) and net Cl absorption (J[sub=net;sup=Cl] ) 10-fold, increases transepithelial potential (V[sub=t]) 4-fold, and reduces transepithelial resistance (R[sub=T]) by 40-65%. The properties of locust Cl transport are not consistent with NaCl cotransport models proposed in other epithelia: i) Cl is absorbed from nominally Na-free saline, ii) there is no correlation between trace amounts of Na contamination and the rate of Cl transport, iii) exposure to cAMP increases ³⁶Cl influx across the apical border into rectal tissue without affecting ²²Na influx, iv) Cl-dependent I[sub=SC] is not inhibited by 1 mM ouabain (2 h) or 1 mN furosemide (1 h), v) J[sub=net;sub=Cl] is not affected when the apical Na electrochemical gradient is reduced by 85%, and vi) there is no relationship between Na and Cl net electrochemical gradients across the apical membrane. Cl/HCO₃ exchange is also unlikely since i) Cl-transport is electrogenic, ii) J[sub=net;sub=Cl] is insensitive to CO₂⁻ and HCO₃⁻ removal, and iii) Cl-dependent I[sub=SC] is not inhibited by 1 mM SITS or 1 mM acetazolamide after 1 h exposure. The cAMP-stimulated system is Cl-selective: Cl >> Br >> I,F,SCN,P0₄,SO₄.C₂H₃O₂,urate. The halide sequence suggests a site having high field strength. Cl-dependent I[sub=SC] is inhibited by low mucosal pH and high osmotic pressure. J[sub=net;sub=Cl] obeys Michaelis-Menten-type kinetics. Mucosal K increases both the K[sub=m] and V[sub=max] of transepithelial Cl absorption (K[sub=a] = 5.3 mM K). The active step in J[sub=net;sub=Cl] is at the apical membrane because net entry of Cl occurs against a large, unfavourable electrochemical gradient. Serosal cAMP and mucosal K directly stimulate the active step since both of these agents cause simultaneous increases in J[sub=net;sub=Cl] and the electrochemical potential opposing CI entry. Passive K transport in the mucosa-to-serosa direction is favoured across apical and basal membranes. Most K absorption (~84%) is electrically coupled to active CI transport under open-circuit conditions, however a small active component is apparent during exposure to cAMP. The response of V[sub=T] to transepithelial salt gradients depends strongly on the direction of the gradients, suggesting that locust rectum is a "tight" epithelium. Intracellular current and fluorescent dye injections reveal strong coupling between rectal cells. Flat-sheet cable analysis indicates that locust rectum becomes "tighter" during cAMP exposure, when transcellular conductance increases from 60 to 95% of the total tissue conductance. cAMP increases apical membrane K conductance and basal membrane CI conductance. K permeability is inhibited by high (physiological) K and osmotic concentrations. The driving force of CI transport is calculated by two independent methods and the results are interpreted in terms of an equivalent electrical circuit model for KCl reabsorption across locust rectum. / Science, Faculty of / Zoology, Department of / Graduate

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13289号 / 論医博第2187号 / 新制||医||1039(附属図書館) / (主査)教授 中山 健夫, 教授 柳田 素子, 教授 佐藤 俊哉 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

The solubility of silver chloride was measured in solutions from 1 x 10^-5M. to 1 x 10^-1M. in chloride ion concentration. Ag^110 was used as a radiotracer to measure the solubility. Evidence for the formation of molecular silver chloride and silver dichloride complex anions was found. A least squares analysis of the experimental data was used to calculate the solubility product constant and the formation constants for the molecular species and the complex ions. The solubility product constant was determined to be 1.74 x 10^-10. The formation constant of the molecular species and the complex ion were calculated to be 1.84 x 10^3 and 1.53 x 10^5 respectively. The agreement of the solubility product constant with that determined by potentiometric measurements was very good. The formation constant of molecular silver chloride was investigated further by extraction with an organic solvent. Nitrobenzene was used as the solvent and the distribution coefficient for the molecular silver chloride in nitrobenzene and aqueous solutions was determined to be 0.32. Evidence was found for the extraction of the molecular species and not the silver ions. However, at high chloride concentrations HAgCl_2 appears to be extracted. By the use of the distribution coefficient, and the concentration of silver in the organic phase, the formation constant of the molecular species was determined to be 1.5 ± .5 x 10^3.