Dissertations / Theses on the topic 'Fish Physiology and Genetics'
To see the other types of publications on this topic, follow the link: Fish Physiology and Genetics.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Fish Physiology and Genetics.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Torati, Lucas Simon. "Reproductive physiology of Arapaima gigas (Schinz, 1822) and development of tools for broodstock management." Thesis, University of Stirling, 2017. http://hdl.handle.net/1893/25801.
Full textAbstract:
Arapaima gigas is the largest scaled freshwater fish in the world reaching over 250 kg. With growth rates of 10 kg+ within 12 months, A. gigas is considered as a promising candidate species for aquaculture development in South America. However, the lack of reproductive control in captivity is hindering the industry expansion. The work carried out in this doctoral thesis therefore aimed to better understand the species’ reproductive physiology, develop tools to identify gender and monitor gonad development, test hormonal therapies to induce ovulation and spawning and characterise the cephalic secretion for its potential roles in pheromone release and during parental care. Initially, a genomic study investigated the overall extent of polymorphism in A. gigas, which was found to be surprisingly low, with only 2.3 % of identified RAD-tags (135 bases long) containing SNPs. Then, a panel with 293 single nucleotide polymorphism (SNP) was used to characterise the genetic diversity and structure of a range of Amazon populations. Results revealed populations from the Amazon and Solimões appeared to be genetically different from the Araguaia population, while Tocantins population comprised individuals from both stocks. This data provided a tool for broodstock identification and future management. The PhD then aimed to evaluate the effects of slow-release mGnRH implants and different broodstock size pairings on maturation and spawning. Results showed that the implants stimulated the brain-pituitary-gonad axis resulting in increased plasma levels of testosterone (females) and 11-ketotestosterone in males, respectively regardless of pairing sizes. However, no spawning was observed. Results also showed the release of sex steroids with potential pheromonal action through the cephalic secretion, a biological fluid released from the adult head along the reproductive period. Thereafter, a non-surgical field endoscopy method was developed and validated for ovarian assessment and gender identification. The method was then used to describe the female gonopore and obtain biopsy of the ovary through cannulation which allowed the description of oogenesis in A. gigas. Importantly, oocytes obtained by cannulation confirmed that adult females under investigation were maturing with oocytes in final maturation stage but failed to ovulate/spawn. Another hormonal induction trial was therefore performed in which a combination of GnRHa (mGnRHa/sGnRHa) was used by injection to induce ovulation and spawning in selected maturing females with effects on oocyte maturation monitored post-induction through biopsy. However, this trial appeared to not be successful at inducing ovulation or spawning. Finally, the peptidome and proteome of the cephalic secretion was further characterised through the comparison between parental and non-parental fish. Results highlighted the complex role of this biological fluid including potential roles on the developing offspring during the parental care period. Overall, this doctoral thesis provided new basic and applied data on A. gigas reproduction and tools that can be used in future studies to better understand the environmental and hormonal control of oogenesis and spawning.
2
Thomson, Jack Sebastian. "Stability of an evolutionary relevant behavioural trait in fish : impact of environmental and genetic variation on behaviour and physiology." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569663.
Full textAbstract:
Personality in animals describes a suite of correlated behavioural traits that distinguishes one individual from another. One important personality measure is boldness, which is related to intraspecific differences in responses to novelty, levels of activity and aggressiveness, propensity for exploration, and capacity for learning and memory. Personality and boldness have previously been linked with physiological responses to stress, termed coping styles, wherein lower stress responsiveness often correlates with bolder behaviour. Variation in these traits has important implications for how animals respond to environmental challenges. Personality and stress responsiveness are both also partly heritable; a greater understanding of the genetic control of behavioural and physiological traits is therefore necessary to understand how individual differences are maintained in the face of natural selection, and how genes can control changes in behaviour and physiology. Boldness and behavioural plasticity was therefore examined in the rainbow trout, Oncorhynchus mykiss Walbaum, which provides an excellent model since the behaviour and physiology of this economically important species has been well-studied. Throughout, boldness was assessed using novel object tests, where latency to approach to within 5 cm of an object was the primary determinant. Trout which approached within 180 s were considered bold, those which did not approach within 300 s as shy, and the remainder as intermediate which were discarded from analysis. Boldness was consistent over time in two lines of rainbow trout bred for a divergent response to stress, but no correlation was found between boldness and either stress responsiveness or gene expression, in contrast to expectations. Stress responsiveness was, however, strongly linked with gene expression: a suite of candidate genes was uniformly upregulated in low stress-responding trout compared to high-responders, suggesting fine control of hormones and receptors throughout the stress response may occur downstream of gene expression. Outbred bold rainbow trout placed into a group of either completely bold or completely shy trout tended to become shyer, whereas initially shy trout did not display any behavioural plasticity. Likewise, bold trout exposed to predation threat in combination with different levels of feed availability modified 'their behaviour seemingly dependent upon the combination of risk level and internal state. Shy trout, again, were less labile. This is in contrast to coping style theory which suggests shy, reactive animals have more behavioural flexibility than bold, proactive individuals. When exposed to variable abiotic factors - increased temperature and reduced dissolved oxygen content - both bold and shy fish exhibited some behavioural change dependent upon the combination of factors. When exposed to these stressors and challenges, plasma cortisol levels more closely matched behavioural profiles such that shy trout generally had a greater stress response than bold trout, and this could be linked to exposure to threat or temperature change. Furthermore, gene expression profiles corresponded with predation threat: genes coding for corticotrophin releasing factor (CRF), ependymin and y-aminobutyric acid A (GABAA) increased in expression under increasing threat levels, indicating these genes were involved in the response to this particular challenge. These results thus show the existence of personality in rainbow trout, linking responses towards novelty with levels of activity and identifying physiological and genetic correlates to these behavioural traits. Boldness was shown not to be a fixed trait but, instead, dependent upon social, environmental, nutritional and energetic state and on intensity of risk. Bold trout generally altered their behavioural strategy in an adaptive manner according to both context and state yet shy individuals remained shy. These empirical data highlight the importance of taking individual personality into account when assessing molecular, physiological and behavioural responses to stimuli. Furthermore, these data provide new insights into intraspecific variation within a variety of contexts that may be used to fuel theoretical models of the evolutionary and ecological significance of animal personalities.
3
Eakins, Felicity Elizabeth Veronica. "Physiology and crossbridge mechanism of boney fish muscle." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497640.
Full text
4
Eakins, Felicity Elizabeth Veronica. "Physiology and Crossbridge mechanism of bony fish muscle." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486589.
Full textAbstract:
Muscle contraction is brought about by the interaction of the proteins actin and myosin. Xray diffraction is a useful tool for gaining information about this process. This thesis reports on the effect of sarcomere length on the X-ray diffraction patterns from active and rigor bony fish muscle. During contraction, sarcomere I.ength changes are known to slow the development of tension (Cecchi et al., 1991) and effect X-ray reflection intensities, (Elliott et al., 1963). Up until now the size of the contractile sarcomere length change in these muscles was unknown and its effect on the tension and X-ray intensities had been neglected (Harford and Squire, 1992). Previously, a time lag was observed between the intensity changes of . the first two major equatorial X-ray reflections (A(10) and A(11�». This led to a hypothesis that the low and high force attached crossbridge states are structurally distinct (Harford and Squire, 1992). In this project, a sarcomere length measurement and control system was developed. The contractile performance of the bony fish muscles was also improved. For the first time, the sarcomere length change during contraction of whole Plaice fin muscle was measured (a reduction of (3.10�±0.06)% per sarcomere) and the system could halve this change. This sarcomere length control was found to significantly increase the rate of tension development. X-ray data also showed a reduction of over half in the lag between the two intensity changes (A(10) and A(11�», providing less clear evidence that the two crossbridge states are structurally different, a finding closer to that seen in frog muscle (Cecchi et al., 1991). Using two pre-existing X-ray datasets, the effect of initial sarcomere length on the state induced in rigor bony fish muscle was also investigated. Evidence from the intensity distributions on the actin layer-lines and from electron density maps of the muscle crosssection, (Harford et al., 1994), suggested that in rigor muscles with a longer initial sarcomere length than the conventional 2.2lJm, a different state was induced in the specimens. This was characterised by a smaller tropomyosin shift, a different crossbridge labelling pattern and a different average head shape, possibly closer to that seen in active muscle.
5
Mainwaring, Gary. "Aspects of fish haematology." Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627994.
Full text
6
Laight, Richard James. "Aspects of the employment of fish to study gene expression and of the effects of the release of transgenic fish." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285882.
Full text
7
Tsang, J. S. H. "The physiology and genetics of bacterial dehalogenases." Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380588.
Full text
8
Furimsky, Marosh. "Intracellular pH regulation in hepatocytes of teleost fish." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58273.pdf.
Full text
9
Perrott, M. N. "The Renin-Angiotensin System and osmoregulation in fish." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233470.
Full text
10
Moorhead, Mayron. "The Metabolic Cost of Electric Signalling in Weakly Electric Fish." Thesis, University of Ottawa (Canada), 2011. http://hdl.handle.net/10393/28900.
Full textAbstract:
Wave-type weakly electric fish emit a highly regular electric discharge using a specialized electric organ. This electric organ discharge (EOD) forms the basis for an electric sense used for navigation, prey detection and communication. The metabolic cost of the EOD is not fully understood, but recent research suggests that it constitutes a significant portion of the fish's energy budget. In the current study, manipulation of metabolic rate via exposure to hypoxia did not significantly alter EOD frequency. Changes in metabolic rate through swimming resulted in EOD frequency increase. To manipulate EOD frequency directly in individual fish, the jamming avoidance response (JAR) and long term frequency elevation (LTFE) were used. EOD frequency elevation and jamming stimulation resulted in an increased M˙O2 possibly associated with increases in sensory processing. Taken together, these data indicate that electric signalling in wave-type weakly electric fish is a not a major contributor to whole-animal energetic cost.
11
Wright, Patricia Anne. "Ammonia stores and excretion in fish : relationship to pH." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27654.
Full textAbstract:
The distribution and transfer of ammonia between intracellular and extracellular compartments of fish and the external water environment was investigated. In vivo and in vitro experiments were performed on the freshwater rainbow trout (Salmo gairdneri) and the intact, seawater lemon sole (Parophrys vetulus).
The distribution of ammonia and H⁺ ions were compared between red cells and plasma (in vivo and in vitro) taken from rainbow trout at rest and during hypercapnia. At rest (in vivo and in vitro) measured intracellular ammonia levels were equal to those predicted by the plasma to red cell pH gradient. The same was not true during hypercapnia, where measured red cell ammonia levels were greater than predicted levels. The addition of the Na⁺/K⁺ ATPase inhibitor, ouabain, had no effect on ammonia accumulation during hypercapnia. It was concluded that ammonia is passively distributed according to plasma-to-red cell H⁺ ion distribution in blood at resting pH values, but under hypercapnic conditions, ammonia accumulation must be due to some other active uptake mechanism.
The distribution of ammonia and ¹⁴C-DMO were compared in white muscle, heart, brain, red cells, and plasma of lemon sole (in vivo) at rest, during hypercapnia, and following exercise. The red cell ammonia distribution at rest and during an extracellular acidosis (hypercapnia and exercise) was similar to that found in rainbow trout. Red cells are unusual in that H⁺ ions are passively distributed according to membrane potential (Em), whereas in other tissues, this is not the case. In white muscle, heart, and brain under all experimental conditions, intracellular ammonia levels far exceeded those predicted by transmembrane pH gradients. Calculated ENH₄₊ values in these tissues were very close to published resting values of Em. It was concluded that NH₄₊ is permeable across cell membranes and that intracellular ammonia stores are not determined by transmembrane pH gradients in lemon sole.
The pH of interlamellar water was investigated in rainbow trout by following changes in the downstream pH of expired water using a stopped-flow method. As water flowed over the gills of control fish, there was a significant decrease in water pH. Acetazolamide (carbonic anhydrase (CA) inhibitor) added to the water increased the CO₂ disequilibrium, while CA eliminated the CO₂ disequilibrium relative to control water. Mucus excreted by the fish was found to contain CA activity by the pH-stat technique. It was concluded that water acidification is due to the conversion of excreted CO₂ to HCO₃₋ and H+ at the gill surface.
A possible function of CA at the external gill surface is to facilitate carbon dioxide and ammonia excretion. Acetazolamide or CA added to the water did not alter carbon dioxide (MCO₂) or ammonia (MAmm) excretion in intact rainbow trout. Methazolamide (CA inhibitor) or methazolamide + amiloride (Na⁺ uptake inhibitor) added to the water had no effect on plasma NH₃ tensions (PNH₃), but increased MAmm slightly compared to control fish. In general, methazolamide resulted in an increase in the diffusing capacity of ammonia. The interpretation of these results was complicated by the fact that rapid serial blood sampling resulted in a universal blood alkalosis. The intact resting fish is unsuitable for studying the interaction between water boundary layer chemistry and excretion across the gill.
With the blood-perfused trout head preparation it was demonstrated that MC0₂ and MAmm are linked through chemical reactions in the external water boundary layer adjacent to the gill. Pre-incubation of blood with acetazolamide reduced MC0₂ and MAMM in the blood-perfused head. Increasing the buffering capacity of inspired water, significantly reduced MAMM, but MC0₂ was unaffected. Each of these experimental treatments significantly reduced the acidification of ventilatory water flowing over the gills. It is proposed that the catalysed conversion of excreted C0₂ to form HCO₃₋ and H⁺ ions in the gill boundary layer provides a continual supply of H⁺ ions needed for the removal of NH₃ to NH₄₊, which reduces water NH₃ levels and facilitates ammonia excretion.
Gas transfer variables in the blood-perfused head preparation were compared to intact cannulated fish with and without oral masks. Oxygen uptake (MO₂) and MCO₂ were lower, and MAMM, higher in the blood-perfused head compared to in, vivo values. these discrepancies were due to differences in venous O₂,
CO₂, and ammonia levels, which determine mean gradients across
the gills. It was concluded that the blood-perfused head is a
suitable preparation for studying the interaction between MCO₂ and MAMM because the overall efficiency of transfer of NH₃ CO₂ was very similar between in. vitro and in vivo preparations,Science, Faculty of
Zoology, Department of
Graduate
12
Tufts, Bruce Laurie. "Ion exchange mechanisms for the control of volume and pH in fish and amphibian erythrocytes." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/29443.
Full textAbstract:
The characteristics of the ion exchange mechanisms which regulate volume and pH in fish and amphibian erythrocytes were investigated and compared. Experiments were carried out under steady state conditions and also following adrenergic stimulation both in vivo and in vitro.
Under steady state conditions, a decrease in extracellular pH caused an increase in the volume of rainbow trout erythrocytes, and a decrease in the intracellular pH. These pH-induced volume changes were mainly associated with movements of chloride across the chloride/bicarbonate exchange pathway. The sodium/proton exchange mechanism is quiescent at all pH's studied under steady state conditions.
Beta adrenergic stimulation of rainbow trout erythrocytes promoted cell swelling and proton extrusion from the erythrocytes. Amiloride inhibited both the volume and pH changes associated with adrenergic stimulation indicating that this response is associated with an increase in the activity of the sodium/proton exchange mechanism on the erythrocyte membrane. The adrenergic swelling and pH responses are enhanced by a decrease in extracellular pH. An increase in bicarbonate concentration reduces the adrenergic pH response, but it is still significant even at 10 mM bicarbonate. DIDS markedly enhanced the beta adrenergic effect on the erythrocyte pH, but abolished the increase in erythrocyte volume. The adrenergic response was independent of temperature between 10 and 18°C. These results support a loosely coupled sodium/proton and chloride/bicarbonate exchange model for the adrenergic response in rainbow trout erythrocytes.
The increases in erythrocyte pH and volume following adrenergic stimulation are associated with increases in the haemoglobin:oxygen affinity. The oxygen carrying capacity of the blood is, therefore, increased following adrenergic stimulation in rainbow trout. Carbon dioxide excretion, however, was not significantly affected by adrenergic stimulation. The functional significance of the adrenergic response of fish erythrocytes may be to offset the effects of the Root shift on the oxygen carrying capacity of the blood during acute changes in extracellular pH.
In contrast to fish erythrocytes, the sodium/proton exchange mechanism in amphibian erythrocytes is active under steady state conditions. In the presence of bicarbonate movements, this exchange significantly affects the erythrocyte volume, but not the erythrocyte pH. Similar to fish erythrocytes, protons are passively distributed in amphibian erythrocytes under steady state conditions and in Donnan equilibrium with chloride ions. The erythrocyte volume also increases with decreases in extracellular pH as in fish erythrocytes, due to changes in the chloride distribution across the erythrocyte membrane.
Adrenergic stimulation does not affect the volume or pH of amphibian erythrocytes either in vivo or in vitro. These animals, therefore, do not appear to regulate erythrocyte pH adrenergically. Amphibians are able to efficiently utilize oxygen stores via both central and peripheral shunting. In addition, the blood of these animals does not have a Root shift. Adrenergic regulation of erythrocyte pH in order to enhance oxygen transport during fluctuations in ambient and internal gas tensions, therefore, is probably less important than it would be in fish.Science, Faculty of
Zoology, Department of
Graduate
13
Reid, Steve G. "Control of catecholamine storage and release in teleost fish." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/9961.
Full textAbstract:
This thesis examined a variety of factors controlling the storage and release of the catecholamine hormones, adrenaline and noradrenaline, from chromaffin cells in teleost fish. In these fish, chromaffin cells line the walls of the posterior cardinal vein (PCV) in the anterior kidney region (head kidney). To examine the process of catecholamine release, an in situ saline-perfused PCV preparation first was developed and validated in the rainbow trout (Oncorhynchus mykiss). The levels of stored catecholamines were approximately 4X greater in trout than in eel, and trout chromaffin cells released greater quantities of catecholamines in response to both 60 mmol 1$\sp{-1}$ K$\sp+$ and carbachol administration, in situ. Thus trout chromaffin cells appear to exhibit a greater capacity to release catecholamines than do eel chromaffin cells which may explain the different plasma catecholamine levels during acute hypoxia. The proximate stimulus for catecholamine release in rainbow trout, during exposure to acute hypoxia, was examined by acclimating trout to either 5 or 15$\sp\circ$C in order to modify haemoglobin oxygen-affinity. At 15$\sp\circ$C, catecholamines were released into the circulation at a PaO$\sb2$ threshold of 34.5 torr while at 5$\sp\circ$C the threshold was 24.0 torr. Release thresholds, calculated on the basis of arterial blood oxygen-saturation were similar at both temperatures (approximately 60% Hb O$\sb2$-saturation). Thus the lowering of blood oxygen content, rather than PO$\sb2,$ appears to be the proximate stimulus causing catecholamine release in rainbow trout during acute hypoxia. In the rainbow trout, intra-arterial injections of serotonin in vivo caused an increase in both plasma adrenaline and noradrenaline levels. In situ, bolus injections of catecholamines which was attenuated by pre-treatment with the serotonergic receptor antagonist, methysergide but unaffected by hexamethonium. Thus serotonin is capable of causing the release of catecholamines by interacting with serotonergic receptors on the chromaffin cells. The effect of adrenocorticotropic hormone (ACTH), the normal secretagogue of cortisol, on catecholamine release, was investigated in the rainbow trout. Intra-arterial injections of ACTH, in vivo, caused an elevation of plasma adrenaline levels. In situ, adrenocorticotropic hormone (ACTH) caused the release of both catecholamines. ACTH-induced release was unaffected by pre-treatment with hexamethonium or methysergide but abolished in Ca$\sp{2+}$-free media. Injections of cortisol in situ did not elicit catecholamine release. ACTH, therefore, is capable of eliciting catecholamine secretion from the chromaffin cells in rainbow trout. (Abstract shortened by UMI.)
14
Howard, Caroline A. "Physiology and genetics of photoacclimation in Arabidopsis thaliana." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419274.
Full text
15
Barnes, Penelope Anne Gee. "Eco-physiology of the endosymbiont-bearing lucinid bivalve, Codakia orbiculata." Thesis, University of Plymouth, 1993. http://hdl.handle.net/10026.1/1081.
Full textAbstract:
The lucinid bivalve Codakia orbiculata, whose gills contain sulphur-oxidizing symbiotic bacteria, occurs in high densities (500/m2) in the rhizosphere of shallow-water Thalassia testudinum sediments in Bermuda. Both sulphide and thiosulphate stimulate aerobic respiration in the isolated bacterial symbionts of C. orbiculata. Sulphide and thiosulphate stimulate anaerobic ^^COa fixation in bacteria isolated from sulphur-starved bivalves. Interstitial water sulphide concentrations in the bivalves' habitat reach 300 pM, and sulphate-reduction rates are high, but thiosulphate concentrations are low (0.66-32.27 pM) . Thiosulphate supplied to the symbionts in vivo must be produced by sulphide oxidation, possibly by the host bivalve. Isolated symbionts also respire aerobically and fix i * C02 in the absence of exogenous reduced sulphur, suggesting utilization of intracellular elemental sulphur stores. Codakia orbiculata symbiotic bacteria are able to respire nitrate. Nitrate concentrations in the interstitial water of C. orbiculata habitat can reach 36 pM. Thiosulphate stimulates nitrate respiration in the intact symbiosis, incubated in oxic and anoxic conditions, and in anoxic incubations of isolated symbionts. Intracellular elemental sulphur is also used by the •bacteria as a substrate in nitrate respiration. Nitrate respiration in the absence of exogenous nitrate suggests that the sjnnbionts may have a limited ability to store nitrate. There is no direct evidence that sulphide stimulates nitrate respiration in either the isolated symbionts or the intact symbiosis, incubated in anoxic conditions. Nitrite respiration in the symbionts is stimulated by sulphide (only), however. Because nitrate respiration was measured by nitrite accumulation, complete denitrification would explain the apparent failure of sulphide to stimulate nitrate respiration. High nitrate respiration rates in the intact symbiosis, incubated with sulphide in oxic conditions, may be in response to thiosulphate, supplied to the bacterial symbionts after host oxidation of sulphide. Nitrite respiration in the intact symbiosis, even when incubated in oxic conditions, demonstrates that the symbionts have access to some sulphide in vivo, however, and that host sulphide-oxidation may not be- 100% efficient. Nitrate and nitrite respiration in the intact symbiosis, even when incubated in oxic conditions, suggests that the bacteria may be exposed to low oxygen levels in vivo and may require the ability to utilize an alternate electron acceptor. Like some free - living bacteria , Codakia orbiculata bacterial symbionts may co-respire, or alternately respire , oxygen and nitrate . The Thalassia testudinum sediments in Bermuda may be ideal for this bacteria-bivalve symbiosis due to the availability of oxygen, nitrate and sulphide.
16
Coombs, Isabel Alexander. "Nutritional physiology of turbot Scophthalmus maximus (L.) : implications to aquaculture." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245324.
Full text
17
Beaumont, Timothy Martin. "Regulation of stress hormone receptors in fish cells." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366436.
Full text
18
Watts, Spencer Maurice. "Studies on the role of commissures in the interocular transfer of spatial visual information in the teleost fish Carassius quratus." Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267770.
Full text
19
Al-Kadhomiy, N. K. "Gill development, growth and respiration of the flounder, Platichthys flesus (L.)." Thesis, University of Bristol, 1985. http://hdl.handle.net/1983/f8e6e177-9551-4e58-b76c-02394305e40c.
Full text
20
Abban, Edward Kofi. "Taxonomy and biochemical genetics of some African freshwater fish species." Thesis, Swansea University, 1988. https://cronfa.swan.ac.uk/Record/cronfa43062.
Full text
21
Choe, Sunghwa. "Genetics and biology of Arabidopsis brassinosteroid dwarf mutants." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/298758.
Full textAbstract:
Brassinosteroids (BRs) have long been known to be effective in plant growth promotion. However, definitive evidence of BR's role in growth stimulation has remained unclear. Recently, genetic approaches using BR-deficient dwarf(dwf) mutants have begun to unravel the role of BRs in plant growth and development. BR dwarf mutants are characterized by multiple growth alterations: robust stem, reduced fertility, prolonged life cycle, dark-green appearance, round and curled leaves, and when grown in the dark, short hypocotyls and expanded cotyledons. Genetic analysis of the dwf mutants defined eight independent genetic loci defective in BR biosynthesis or perception. Allelism tests with previously reported genes revealed that d̲i̲m̲inuto 1 (dim1) was an allele of dwf1, and dwf2, dwf3, and dwf6 are allelic to b̲r̲assinosteroid i̲nsensitive (bri), c̲onstitutive p̲hotomorphogenesis and d̲warfism (cpd), and d̲e̲-e̲t̲iolated2 (det2), respectively. dwf4, dwf5, dwf7, and dwf8 were found to be novel and are the focus of this research. Anatomical analysis demonstrates that a reduction in cell length causes dwarf phenotype. Dwarfism was rescued by exogenous application of BRs. Feeding studies utilizing BR biosynthetic intermediates were employed to identify defective steps of BR biosynthesis in each of these dwarf mutants. dwf4 mutants were rescued only by 22α hydroxylated BRs, suggesting that the 22α hydroxylation reactions, putative rate-determining steps, are blocked. In fact, DWF4 has been cloned and shown to encode a cytochrome P450 steroid hydroxylase. Feeding studies also showed that dwf8 plants are rescued only by intermediates after 3 dehydrogenation reactions, indicating that the 3-dehydrogenase is defective in dwf8 plants. Gas Chromatography-Selective Ion Monitoring (GC-SIM) analysis of endogenous BRs in dwf5 plants showed that the level of 24-methylene cholesterol is greatly diminished as compared to wild type, suggesting that the biochemical defect occurs before 24-methylene cholesterol. Similar to dwf5, the biosynthetic defect in dwf7 is also shown to be in a step before 24-methylene cholesterol. The pleiotropic phenotypes in these dwf mutants due to biochemical defects in BR biosynthesis suggests that BRs are essential for proper growth and development of plants.
22
McKendry, John E. "Carbon dioxide chemoreception and the cardioventilatory effects of hypercarbia in fish." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/8996.
Full textAbstract:
In situ and in vivo experiments were performed on rainbow trout (Oncorhynchus mykiss) to examine (i) the direct effect of CO2 on the systemic vasculature and (ii) the influence of internal versus external hypercarbic acidosis on a variety of cardiovascular variables. Adult Atlantic salmon (Salmo salar) were exposed to acute, localized environmental hypercarbia (2.0 and 4.0% CO2 in air) over the gills via injections (60 ml/kg) of equilibrated seawater directly into the buccal cavity. Adult Atlantic salmon (Salmo salar) and Pacific spiny dogfish (Squalus acanthias) were exposed to acute environmental hypercarbia (approximately 20 min). Experiments were performed to examine the influence of environmental hypercarbia on aspects of cardiorespiratory physiology, and in separate series of experiments the muscarinic antagonist atropine (100 nmol kg-1; both species) and complete branchial denervation (dogfish) were used to investigate putative CO2-chemoreceptive sites on the gills and their link to the autonomic nervous system. The homogeneity of the cardiovascular and ventilatory responses amongst fish to elevated ambient CO2 was investigated by exposing six species of fish to acute environmental hypercarbia (approximately 20 min). The experiments were performed in vivo using two marine teleosts, Atlantic salmon (Salmo salar) and Pacific sanddab (Citharychthus sordidus); two freshwater teleosts, brown bullhead (Ictalurus nebulosus) and American eel (Anguilla rostrata); as well as one marine elasmobranch, the Pacific spiny dogfish (Squalus acanthias). (Abstract shortened by UMI.)
23
Carey, Geoffrey Roy. "Triploidy induction in Australian native fish." Thesis, Queensland University of Technology, 1994. https://eprints.qut.edu.au/37164/1/37164_Carey_1994.pdf.
Full textAbstract:
Although triploidy has been induced in many cultured fish species throughout the world, to date no work of this type has been attempted on Australian native fish. There has also been little study of the chromosomes of Australian native fish. This study aimed to assess the viability of using cold shock to treat recently fertilised eggs of Rainbowfish (Melanotaenia duboulayi), Silver Perch (Bidyanus bidyanus), Bass (Macquaria novemaculeata) and Barramundi (Lates calcarifer) to induce triploidy. A secondary aim was to determine the complete karyotypes for the experimental species.
Sub lethal cold treatments of between 30 and 60 minutes applied to recently fertilised eggs produced, at best, low rates of triploidy in Rainbowfish ( 11.1 % triploids from a 45 minute 5°C treatment applied 15 minutes post fertilisation) and Bass (9. 1 % triploids from a 30 minute 4°C treatment applied 9 minutes post fertilisation). Sub lethal cold treatments of 60 minutes performed on recently fertilised Silver Perch eggs failed to produce triploid fish.
The diploid chromosome number, chromosome formulae and completed karyotypes are presented for three species: Rainbowfish (2n= 48, n= 24 telocentric), Silver Perch (2n= 48, n= 1 submetacentric + 23 telocentric) and Bass (2n= 48, n= 1 metacentric + 1 sub metacentric + 22 telocentric) for which this information was not known; and is also given for Barramundi (2n=48, n= 1 metacentric + 1 sub metacentric + 3 subtelocentric + 19 telocentric ), the karyotype of which has not previously been described from Australian fish.
The results achieved here indicate that cold shock is not a reliable method for inducing triploidy in the species trialed in this study. It is proposed that any future studies on the induction of triploidy in native freshwater fish species be performed using either pressure or heat shock techniques at approximately 15 and 9 minutes post fertilisation for Rainbowfish and Bass respectively, as exposure of eggs to these treatments may produce higher rates of triploidy.
24
Ramsden, Christopher. "The effects of manufactured nanoparticles on fish physiology, reproduction and behaviour." Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1170.
Full textAbstract:
Over the last decade the development and use of nanomaterials (NMs) and nanoparticles (NPs) has increased at a great rate. As a result there is an ever increasing risk of exposing humans and wildlife to these potentially harmful materials. Titanium dioxide nanoparticles (TiO2 NPs) and carbon nanotubes (CNTs) are two of the most widely used NMs at present. Their potentially harmful effects on organisms and physicochemical properties have been investigated in a growing number of scientific studies. However understanding the level of risk they may pose is far from satisfactory. The present body of work has addressed various aspects of this field. In order to better quantify the fate of TiO2 NPs in the environment the methodology of measuring Ti from TiO2 NPs was improved using ICP-OES and single particle ICP-MS was demonstrated to provide the first steps towards characterising the nature of TiO2 NPs in liquid-phase media. The potential harm of TiO2 NPs and single walled carbon nanotubes (SWCNTs) to zebrafish was investigated in two separate studies. Little evidence of physiological toxicity was found and the only nano-scale effect of note was an increase in total glutathione of zebrafish exposed to TiO2 NPs. More subtle effects in reproductive studies were further investigated using the three-spined stickleback in a longer term investigation. Similarly to the zebrafish there was little evidence of any physiological disturbances and the well documented reproductive behaviour of the stickleback was not significantly altered as a result of TiO2 NP exposure. This body of work has added to the understanding of the potential toxic effects caused by exposure to both TiO2 NPs and SWCNTs. Improved methods for the detection and characterisation of TiO2 NPs have been demonstrated and the most sensitive tools for ecotoxicological assessments of NP toxicity have been elucidated.
25
Warne, Justin Mark. "Arginine vasotocin's role in the adaptive osmoregulatory physiology of euryhaline fish." Thesis, University of Manchester, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488113.
Full textAbstract:
A specific radioimmunoassay was developed and characterised for the measurement of arginine vasotocin (A VT) in teleost fish. Crossreactivity of the antibody with the other teleost neurohypophysial peptide, isotocin, was less than 1 % and the sensitivity of the assay 0.25 pglassay tube. Rapid blood sampling, within 1 minute of capture, by needle puncture of the caudal blood vessels, and collection of blood through chronic arterial cannula 1 - 4 days after surgery were identified as procedures which did not influence plasma ion levels, osmolality or hormone concentrations. These procedures were used in later experimental protocols examining the effects of chronic and acute osmotic stimuli on plasma A VT concentrations. Plasma A VT concentrations in a range of euryhaline and stenohaline teleost fish were measured at 10-12 to low 10-11 M (1-20 pglml). There was no consistent difference in circulating A VT levels in euryhaline fish (flounder, eel and trout) adapted to fresh water (FW) or seawater (SW) for at least 2 weeks. The flounder was studied in greater detail and seasonal influences were identified as having an effected on osmoregulation. In the winter/spring period plasma osmolality was significantly lower in FW adapted fish than at other times of the year. In SW adapted fish at this time plasma osmolality was elevated and this was accompanied by elevated plasma A VT concentrations. The winter/spring period was associated with the development of the gonads and this factor may affect osmoregulation in the flounder. In SW adapted flounder a positive linear relationship between plasma A VT and plasma osmolality and ion levels was observed, indicating a link between these two parameters but no such relationship was evident in FW adapted fish. Chronically cannulated SW adapted flounder were used to examine the effects of acute osmotic stimuli on plasma A VT concentrations. Intraperitoneal injection of hypertonic saline acutely increased plasma osmolality and was associated with a significant increase in plasma A VT concentration, indicating that A VT secretion was sensitive to increased plasma osmolality. The expansion of extracellar fluid volume via intravascular infusion of isotonic saline reduced plasma A VT concentrations independently of any change in plasma osmolality. This indicated that vascular volume also influences plasma A VT concentrations. Reducing blood volume by haemorrhage and lowering plasma osmolality by infusion of hypotonic saline did not result in any change in plasma A VT concentrations. Plasma A VT concentrations were measured in lamprey at a 10-12 M concentration, and the transfer of lamprey from FW to Baltic SW caused an initial rise in plasma A VT concentrations, suggesting that A VT is involved in osmoregulation in these fish. A VT immunoreactivity was also demonstrated in two species of elasmobranch fish in a 10-12 to low 10-11 M range.
26
Arnold-Reed, Diane Elizabeth. "The caudal neurosecretory system and its role in fish osmoregulatory physiology." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329615.
Full text
27
Salze, Guillaume Pierre. "Nutritional control of gene expression, larval development and physiology in fish." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29655.
Full textAbstract:
During preliminary research on cobia (Rachycentron canadum, L.) it became increasingly clear that more in-depth information was required to provide enabling techniques for the cobia aquaculture industry to develop more rapidly. A unifying theme in many of the more important issues facing cobia aquaculture is nutrition. This led to nutritional investigations with larval and juvenile fish highlighting the impacts of dietary ingredients on animal performance. Indeed, nutrition can be viewed as a central lever of action through which many aspects of the physiology and the environmental (water) quality of the animal can be controlled.
The first project focused on studying the larval development of cobia, a fish species highly suitable for aquaculture for which the industry is nascent. I described the time-course of development of external sensory organs, gut morphology and relevant digestive enzymes under controlled conditions using electron microscopy, histology and spectrophotometric assays. The developmental sequence of larval cobia could be separated in two phases, with a transition period between 12 and 14 days post hatch (dph). This transition is characterized by the formation of the intestinal loop, the establishment of basic cranial neuromast configuration, leading to the initiation of the onset of pancreatic enzymes and the increase of growth rate. In addition, the effects of dietary taurine supplementation and incorporation of mannan oligosaccharides (MOS) into live feeds on cobia larvae development was examined. Fish fed supplementary MOS did not grow faster but displayed higher microvilli length and density. In addition, MOS-fed fish were more resistant to salinity stress. The dietary supplementation of taurine resulted in a dramatic increase in survival, growth and development rates, and enzymatic activities.
The second project aimed at refining cobia juvenile nutrition, assessing fish meal and fish oil replacements. Novel sources, including soy protein and oil, were investigated with and without amino acid and MOS supplementations, yielding promising results. Indeed, both fish meal and fish oil were replaced completely and successfully in feeds for juvenile cobia. In addition, novel ingredients (e.g. marine algae meals and soy protein concentrate) were identified to effectively achieve such replacement.
The third and last project dealt with nutrient-gene interactions, specifically centering attention on immunostimulants for which the underlying mechanisms of action remain poorly characterized. Here, dietary MOS, nucleotides and selenomethionine (Se-met) were offered to zebrafish whose transcriptome was analyzed by microarray. The immune system, humoral or cellular, innate or adaptive, exhibited different patterns of response according to the immunostimulating nutrient used. In addition, various genes involved in cell cycle and cytokinesis were concomitantly expressed. An intriguing observation related to the insulinomimetic effect of Se-met. In other words, Se-met impacted pathways normally regulated by insulin, such as the MAPK and PI3K pathways. Some Insulin-like Growth Factors (IGF) and IGF bindgin proteins were up-regulated. Additional research is however necessary prior to advocating for the use of these additives, in order to further investigate their respective pros and cons.Ph. D.
28
Rogers, Nicholas John. "The respiratory and gut physiology of fish : responses to environmental change." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/19295.
Full textAbstract:
Many of the habitats occupied by fish are highly dynamic, naturally demonstrating substantial abiotic fluctuations over diurnal, tidal or seasonal cycles. It is also the case that throughout their 545 million year evolutionary history, fish have existed in aquatic environments very different to those of the present day. However, the past several decades have seen unprecedented rates of environmental change, at local and global scales, arising from human activities. The two major themes of the present thesis are: 1) Respiratory responses of fish to changes in environmental oxygen and temperature in the context of exploring intra- and inter-specific trait variation and its ecological implications 2) The effects of environmental factors (oxygen, carbon dioxide, temperature and seawater chemistry) on the intestinal precipitation and excretion of calcium carbonate by marine teleosts. In the first study (chapter two) a comprehensive database of fish critical PO2 (Pcrit) data compiled from the published literature is presented. The systematic review of this literature provided the opportunity to critically examine methodologies for determining Pcrit as well as its usefulness as an indicator of hypoxia tolerance in fish. The second study (chapter three) examines whether inter- and intra-specific variation in thermal and hypoxia tolerance in two reef snapper species (Lutjanus carponotatus and Lutjanus adetii) reflects their distributions across the contrasting biophysical environments of the reef flat and reef slope surrounding Heron Island on the Great Barrier Reef. L. carponotatus was clearly the most thermally and hypoxia tolerant of the two species, demonstrating a ~3.5 °C wider thermal tolerance zone (higher CTmax, lower CTmin) and ~26% lower Pcrit than L. adetii. These results suggest that the contrasting distribution of these species between flat and slope reef zones is reflected in their physiological tolerances. However, there was no evidence of intra-species variation in tolerance between flat and slope caught L. carponotatus individuals, indicating that this species does not form physiologically distinct subpopulations between these reef zones. The third study (chapter four) experimentally quantified the effect of hypercarbia (3000 μatm) and hypoxia (50% air saturation) on gut carbonate production by the European flounder (Platichthys flesus). Both hypercarbia and hypoxia resulted in a significant increase in carbonate excretion rate (1.5-fold and 2.4-fold, respectively) and acted synergistically when combined. In the final study (chapter five), gut carbonate production was measured in the European flounder undergoing conditions simulating the ‘calcite seas’ of the Cretaceous. The results of this study support the hypothesis that ocean conditions prevalent during the Cretaceous period resulted in piscine carbonate production rates substantially higher (~14-fold) than the present day. Ultimately, this thesis directly links the environmental physiology of fish at the individual level to wider scale implications (past, present and future), ranging from local ecological patterns all the way up to global carbon cycles.
29
Bielanska, Magdalena M. "Telomeric probes for FISH, technical aspects and clinical applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0026/MQ37095.pdf.
Full text
30
Rzhepishevska, Olena. "Physiology and Genetics of Acidithiobacillus species : Applications for Biomining." Doctoral thesis, Umeå : Department of Molecular Biology, (Faculty of Science and Technology), Umeå Univ, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1545.
Full text
31
Mejia, Carranza Jaime. "The physiology and genetics of APX2 in Arabidopsis thaliana." Thesis, University of East Anglia, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446494.
Full text
32
Viger, Maud. "Physiology, genetics and genomics of drought adaptation in Populus." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/202473/.
Full textAbstract:
As the demand for energy rises, Populus species are increasingly grown as bioenergy crops. Meanwhile, due to global change, predictions indicate that summer droughts will increase in frequency and intensity over Europe. This study was carried out to evaluate the adaptation to drought in Populus, at different levels: genetic, genomics and physiology. Forests trees such as poplar are very important ecologically and economically but the Populus genus is known to be drought sensitive. Consequently, it is essential to understand drought response and tolerance for those trees. Two populations of poplar were used for this study, a mapping population (Family 331) and a natural population of Populus nigra. The F2 mapping population obtained from a cross of Populus deltoides and Populus trichocarpa, showed differences in stomatal conductance and carbon isotope composition in both clones and the F2 progeny. It was also used to discover QTL related to water use efficiency highlighting interesting areas of the genome. Combining QTL discovery and microarray analysis of the two clones in response to drought, a list of candidate genes was defined for water use efficiency. The natural population of Populus nigra consisting of 500 genotypes of wild black poplar showed variation in numerous physiological measurements such as leaf development and carbon isotope discrimination in well-watered conditions depending on their latitude of origin. The drier genotypes (from Spain and South France) had the smallest leaf area which could be linked to an adaptation to drought. Physiological measurements of extreme genotypes in leaf size of this population revealed differences in response to water depending on their latitude of origin. Stomatal conductance rapidly decreased and water use efficiency improved for Spanish genotypes after a slow and moderate drought stress. Direct comparisons between the transcriptome of extreme genotypes from Spain and North Italy in well watered and drought conditions provided an insight into the genomic pathways induced during water deficit. Six candidate genes were selecting for further analysis using real-time PCR: two stomatal development genes (ERECTA and SPEECHLESS), two ABA related genes (ATHVA22A and CCD1), a second messenger (IP3) and a NAC transcription factor (RD26)
33
Elgar, Greg. "Analysis and characterisation of the small genome of the puffer fish (Fugu)." Thesis, Open University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359243.
Full text
34
Dave, Emma. "The physiology of the Escherichia coli pyruvate dehydrogenase complex." Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364242.
Full text
35
Saraiva, Marcia. "Functional characterisation of genes from the fish pathogenic oomycete Saprolegnia parasitica." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=225277.
Full textAbstract:
Saprolegnia parasitica is one of the most devastating animal pathogenic oomycetes causing massive economic losses every year worldwide. The disease – saprolegniosis, is characterised by the appearance of white cotton-like spots on the skin, fins and gills of freshwater fish, leading to its death by haemodilution. More efficient control methods will be derived from a better understanding of S. parasitica, but inefficient transformation protocols currently are limiting the basic molecular knowledge This thesis describes the first application of transient gene silencing in S. parasitica. A gene that codes for a putative tyrosinase from S. parasitica, SpTyr, was selected to investigate the suitability of the RNAi technique to functionally characterise genes. Transient gene silencing can be used to functionally characterise genes in S. parasitica. In order to infect a host organism S. parasitica needs to attach to it. We found that detachment of S. parasitica cysts requires strength 3 times higher when compared to other Saprolegnia spp. I also demonstrate through functional genomics that a gene, SPRG_018636, that encodes for a fibronectin protein is involved in spine formation. Aquacultures often use, as a method of sterilisation, UV systems. This method has proven to be efficient against bacteria, virus and protozoa. However, we studied the effect of UVB and UVC on the growth of several oomycetes including S. parasitica and Saprolegnia diclina and it was found that S. parasitica is UV resistant. Key players from the resistance mechanism were not identified but significant knowledge was acquired on recovery from UV damage. Small steps were taken towards the development of a stable transformation protocol with the work on this thesis. Nevertheless, further studies will be necessary to accomplish this goal. Functional characterisation of a homolog of PiNuk7 found in S. parasitica genome was performed. This protein unlike Phytophthora infestans homolog did not translocate into the host cell.
36
Fitzcharles, Elaine M. "Genetic diversity of Antarctic fish." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/6860.
Full textAbstract:
Correct species identification is fundamental to all areas of biology, but particularly the policy related areas of conservation and fisheries management. To enable guidelines to be developed for environmental management and conservation, such identifications need links to studies of the evolutionary history, biological factors and environmental influences driving species divergence and population dynamics for the target species. This study concerns two genera of gadiform fish, Muraenolepis and Macrourus, found in southern temperate and Antarctic waters, with a single species, Macrourus berglax, present in the North Atlantic. With similar distribution patterns to toothfish species, Dissostichus eleginoides and D. mawsoni, they are a major food source and by-catch of the toothfish fishery. Both are slow growing and long lived, with different evolutionary histories, life expectancies and strategies for reproduction. For both genera, the accuracy of morphological keys, number of described species and their distribution is under debate. This study has identified specimens to species level using both morphological and genetic techniques, redefining the range for morphological features and taxonomic keys. For Muraenolepis, this has clarified confusion over Mu. marmoratus and Mu. microps being a single species, confirmed some mis-identification from sexual dimorphism and provided genetic evidence for the recently described species Mu. evseenkoi. For Macrourus, this work has identified a new species, now named Ma. caml, and found that Ma. holotrachys and Ma. berglax are genetically identical, raising the question of bipolar distribution or recent divergence. The low level of genetic variation within both species suggests a recent evolution and expansion into Antarctic waters. Similar geographic species limits imply common processes influencing divergence, with the oceanographic fronts as potential barriers. Further investigation of niche overlap and fine scale population structure are required to fully understand the processes driving speciation and provide the underlying data required for fisheries management.
37
Paxton, C. G. M. "Genetics and environmental components of behavioural variation within guppy, Poecilia reticulata, populations in Trinidad." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259896.
Full text
38
Sodsuk, Panom Krachangpoj. "Molecular genetics and systematics of tilapiine cichlids using allozymes and morphological characters." Thesis, University of Stirling, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385126.
Full text
39
Collinder, Eje. "Intestinal functions in animals : an experimental study on horses, pigs, cows and fish /." Stockholm : Karolinska Univ. Press, 2001. http://diss.kib.ki.se/2001/91-7349-066-0/.
Full text
40
Bhaskaran, Ambily. "Tumour suppressor genes in fish : molecular biomarkers for carcinogens in the aquatic environment." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286800.
Full text
41
Canario, Adelino Vicente Mendonca. "Involvement of ovarian Câ†2â†1 steriods on oocyte final maturation in rainbow trout, (Salmo gairdeneri), plaice (Pleuronectes platessa) and dab (Limanda limanda)." Thesis, University of East Anglia, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327792.
Full text
42
Nati, Julie Jeanne Helene. "Invasion physiology : do physiological characteristics facilitate the spread of invasive fish species?" Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/8104/.
Full textAbstract:
A considerable number of abiotic (e.g. temperature) and biotic factors (e.g. intra-interspecific interactions) contribute in shaping species’ distribution and invasiveness but knowledge is still lacking regarding the importance of physiological and behavioural traits in determining the distributions of ectotherms and especially the invasion success of non-native species into novel habitats. With rising temperatures, distribution shifts in many of fish species have been observed. Additionally, changing thermal conditions are facilitating the colonisation of invasive species. It is crucial that we gain an increased understanding of the mechanisms underlying the effects of environmental change on the distribution of aquatic species and the ecological damage caused by invasive species. Physiological traits are likely to present a fundamental constraint on the environments that are habitable to a given species. Whole animal traits associated with energy metabolism and locomotory performance are especially likely to be important in this regard. Nevertheless, the effects of traits such as metabolic rate and aerobic scope (AS) on the distributions of native and invasive species have not been thoroughly studied. In a first step toward understanding these effects, I performed a phylogenetically-informed analysis of links between AS and absolute latitudinal distribution range in 86 fish species. From the results obtained in Chapter 2, I found no evidence for the direct implication of AS in the currently observed distributions of fishes. Moreover, no association between AS and invasion success in 59 freshwater fish species (23 invasive and 36 native species) was found. These results suggested that peak AS is not a constraining or determining factor in the distribution range and invasion success in fish. Following on from these results, there is a possibility that there could be a trade-off between peak and breadth of performance for AS across temperatures in fishes. Species with a higher peak AS might only be able to function normally over a narrow range of temperatures. In Chapter 3, I collected AS data from literature and conducted phylogenetical-informed analysis to test the trade-off theory in AS across 28 fish species. No evidence could be found for a trade-off between peak and breadth performance in AS for fish. Interspecific competition between invasive and native fish species might cause changes in the structure of native fish communities. Furthermore, these interactions can vary over competitive context (e.g. for prey or cover), differ over a range of environmental factors (e.g. in response to temperature variation) and be linked directly or indirectly to species’ metabolic capacity (e.g. aerobic scope). With increasing temperatures, invasive species might gain a competitive advantage over the native species though shifts or changes in competitive behaviour and traits such as AS. After having investigated broad patterns among AS and geographical distributions in fishes, the remainder of my thesis focused on trade-offs in energy allocation and tolerance to environmental stressors in a pair of species to determine the role of aerobic capacity as a factor in competition between these two species. Specifically, I examined interactions between native stone loaches (Barbatula barbatula) and invasive bullheads (Cottus gobio), two species which occupy the same ecological niche and that are believed to compete for similar habitats. Physiological and behavioural traits could play an essential role in the spread of invasive species, particularly the internal underlying mechanisms that modulate an organism’s response to environmental changes. In Chapter 4, I examined physiological and behavioural responses of invasive bullheads and native stone loaches to acute and acclimated temperature shifts (13-21°). I found that invasive bullheads had a lower AS than stone loaches over all temperatures tested. Bullheads were also less active overall and preferred colder temperatures (17.5-19°C) than stone loaches (21-22.4°C). Therefore, changes in AS in response to thermal variation are unlikely to be a contributing factor in invasion success of bullheads in Scottish rivers. In Chapter 5, I investigated the direct competitive interactions between bullheads and stone loaches at three different temperatures (13°C, 17°C and 21°C). Overall, native stone loaches were better competitors for shelter use and in particular at colder temperatures. There was no clear causal effect of temperature or AS on competitive outcomes between these two species. Low competitive ability found in invasive bullheads suggests that bullheads may not be actively displacing stone loaches. It has been suggested that a successful invader should have a wide tolerance range for different environmental factors. For example, invasive species might be more tolerant to hypoxic events as compared to native species. In Chapter 6, I looked at the hypoxia tolerance and avoidance behaviour of bullheads and stone loaches over different dissolved oxygen (DO) concentrations (100%, 80%, 60%, 40%, 30%, 25% and 20% DO levels). Surprisingly, I found that bullheads were less tolerant to hypoxic conditions with a Pcrit value of 4.96 mg O2 l-1 at 14°C. Avoidance behaviour towards progressive hypoxia was similar between bullheads and stone loaches; both species spent most of their time utilising the shelter even in hypoxic conditions. Low tolerance towards hypoxia did not give an advantage to invasive bullheads over native stone loaches in particular during harsh environmental conditions. The results from this thesis suggest that metabolic traits may not play as strong a role in constraining species distributions as previously suspected, particularly in the specific case of interactions between native stone loaches and invasive bullheads in Scotland. Instead, other physiological factors, life history traits, and population demographics may play a primary role in affecting invasion success in this case.
43
Moortgat, Katherine Tina. "Precision of pacemaking in a weakly electric fish : behavior, physiology, and modeling /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9926562.
Full text
44
Adams, Gianetta Lynn. "Morphology, genetics and physiology of a troglomorphic sculpin, Cottus carolinae /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1068220111&sid=25&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Full text
45
Cochran, Maria Karin. "Uptake Routes of Benzo[a]pyrene in an Estuarine Killifish: Cytochrome P4501A Immunohistochemistry using Whole Fish." W&M ScholarWorks, 1994. https://scholarworks.wm.edu/etd/1539617672.
Full text
46
De, Basso Rachel. "Influence of genetics and mechanical properties on large arteries in man." Doctoral thesis, Linköpings universitet, Fysiologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-29492.
Full textAbstract:
Arterial pathology is the major contributor to cardiovascular diseases and mortality. The mechanical properties of arteries are independent factors for cardiovascular disease and mortality, where genetics influence the structure of the arterial wall, which may result in change in arterial stiffness. The aims of this thesis were to study the mechanical properties of the popliteal artery (PA) in healthy subjects and the influence of angiotensin-converting enzyme (ACE) polymorphism and Fibrillin-1 (FBN1) polymorphism on large arteries. Further, the impact of FBN1 polymorphism on cardiovascular morbidity and mortality was investigated. The PA is, after the abdominal aorta, the most common site of aneurysmal development. The PA was studied in healthy subject with ultrasound and the diameter increased and the distensibility decreased with age, with men having lower distensibility than women. This seems not to be the behavior of a true muscular artery but rather of a central elastic artery such as the aorta, and might have implications for the susceptibility to aneurysm formation, as well as the association of dilating disease between the PA and the aorta. The wall stress in the PA was low and unaffected by age, probably caused by a compensatory remodeling response with an increase in wall thickness. This indicates that other mechanisms than wall stress contribute to the process of pathological dilatation in the PA. The ACE D allele may be associated with abdominal aortic aneurysm. Elderly men with the ACE D allele were associated with increased abdominal aortic stiffness compared to men carrying the I/I genotype. This suggests that the ACE D allele impairs arterial wall integrity, and in combination with local hemodynamic and other genetic factors it may have a roll in aneurysm formation. The FBN1 2/3 genotype has been associated with increased systolic blood pressure. The FBN1 2/3 genotype in middle-aged men was associated with increased abdominal aortic stiffness and blood pressure which indicates an increased risk for developing cardiovascular disease. The increased presence of plaque in the carotid artery of middle-aged men with the FBN1 2/3 genotype indicates a pathological arterial wall remodeling with a more pronounced atherosclerotic burden, but did however not affect the risk of cardiovascular events and/or death in this population. This relationship needs to be studied further.
47
Sene, Viviani França [UNESP]. "Citogenética molecular e caracterização cromossômica no gênero Eigenmannia (Teleostei, Gymnotiformes, Sternopygidae)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/99394.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:30:12Z (GMT). No. of bitstreams: 0
Previous issue date: 2011-07-29Bitstream added on 2014-06-13T20:39:50Z : No. of bitstreams: 1
sene_vf_me_botib.pdf: 1250166 bytes, checksum: ef91b80ce3068f6731dda41593edae4e (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Foram analisadas seis espécies/citótipos de peixes do gênero Eigenmannia, Eigenmannia sp1, Eigenmannia sp2, E. cf. trilineata, Eigenmannia sp e dois citótipos de E. virescens de diferentes bacias hidrográficas brasileiras, com o uso de técnicas citogenéticas básicas (coloração com Giemsa, localização das RONs pela marcação com nitrato de Prata e bandamento C) e moleculares (hibridação fluorescente in situ com sondas de DNAr 18S e 5S, com sondas teloméricas (TTAGGG)n, com sondas para elementos retrotransponíveis Rex 1 e Rex 3 e também por microdissecção, amplificação e hibridação in situ fluorescente com sonda produzida a partir do cromossomo sexual Y de Eigenmannia sp2). As espécies/citótipos analisados apresentaram intensa variação em seus números diploides, de 2n=28 cromossomos em Eigenmannia sp1, 2n=31/32 em Eigenmannia sp2, 2n=34 em E. cf. trilineata, 2n=36 em Eigenmannia sp e 2n=38 em E. virescens, além da ocorrência de sistema sexual XX-XY no citótipo de E. virescens do rio Ribeirão Claro (chamado de E. virescens-XY) e ausência desse sistema no citótipo do rio Mogi-Guaçu (chamado de E. virescens), bem como a ocorrência de sistema múltiplo do tipo X1X1X2X2-X1X2Y em Eigenmannia sp2 do rio Araquá. O DNAr 5S está organizado em duas classes distintas e foi localizado em diferentes cromossomos entre estas espécies/citótipos, mas sempre em posição terminal dos cromossomos, com exceção apenas do par cromossômico 7 de Eigenmannia sp1, que possui DNAr 5S em posição intersticial. Ainda, sequências de DNAr 5S foram localizadas no par sexual XY do citótipo de E. virescens-XY, evidenciando uma nova característica dos cromossomos sexuais deste grupo. As RONs, identificadas pelo tratamento com nitrato de Prata e pela sonda de DNAr 18S, foram sempre localizadas em compartimentos cromossômicos distintos do DNAr 5S e, apesar de serem localizadas...
Conventional (Giemsa, Ag-NOR, C-banding) and molecular (Fluorescent in situ hybridization with 18S and 5S rDNA probes, telomeric repeats (TTAGGG)n, Rex1 and Rex3 retrotransposable elements and microdissection, amplification and fluorescent in situ hybridization with probes produced from the Y sex chromosome of Eigenmannia sp2.) cytogenetic studies were carried out in six fish species/cytotypes of the genus Eigenmannia from different Brazilian hydrographic basins. The analyzed species/cytotypes presented an intense variation in diploid number, ranging from 2n=28 chromosomes in Eigenmannia sp1, 2n=31/32 in Eigenmannia sp2, 2n=34 in Eigenmannia cf. trilineata, 2n=36 in Eigenmannia sp to 2n=38 in E. virescens, besides the occurrence of a sex chromosome system XX-XY in the cytotypes of E. virescens from Ribeirão Claro river (named as E. virescens-XY) and absence of this sex chromosome system in the cytotypes of Mogi-Guaçu river (named E. virescens), as well as the occurrence of a multiple sex chromosome system X1X1X2X2-X1X2Y in Eigenmannia sp2 from Araquá river. The 5S rDNA is organized in two distinct classes and was located in different chromosomes between these species/cytotypes; on the other hand, the location in the terminal position of chromosomes was a conserved feature, with exception of chromosome pair 7 in Eigenmannia sp1, which had 5S rDNA sites in an interstitial position. Yet, 5S rDNA signals were detected on the XY sex chromosome of E. virescens-XY, showing some new characteristics of sex chromosomes in this group. The NORs, identified by silver nitrate staining and 18S rDNA probes, were always located in distinct chromosome compartments of 5S rDNA and besides located in different chromosomes in all analyzed samples, they remained conserved through the karyotypic differentiation process in this group. The analysis of constitutive heterochromatin... (Complete abstract click electronic access below)
48
Esterhuyse, M. M. "Microsatellite markers to identify two species of Tilapiine fish, Oreochromis mossambicus (Peters) and O. niloticus (Linnaeus)." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52935.
Full textAbstract:
Thesis (MScAgric)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: Forming part of a conservation programme, this study was concerned with two species of Cichlid fish (Oreochromis mossambicus and O. ni/oticus), which were brought into contact with each other by unnatural ways. They are now hybridizing to some extent and there is also evidence that the foreign O. ni/oticus may out compete the native O. mossambicus. To cast light on what the current distribution is of both these species and the hybrids in Southern Africa, it is important to identify specimens very accurately. In attempting to find genetic markers to distinguish between two species of Cichlids we tested 20 microsatellite dinucleotide (CAn) repeats during a preliminary study and found five of these promising to exhibit little intra-specific genetic diversity but large genetic variation between species. We amplified these five loci in 145 individuals from 10 populations, which included the two species and their hybrids. Exact sizes of the fragments were determined using an automated DNA sequencer. Between the two species, allele sizes were overlapping, but when data were analyzed by statistical models, the differences could be seen for populations, however on individual level there was overlap between the species. The hybrids were found to be intermediate positioned between the two pure species. Our attempt to assign individuals to populations provided doubtful results. Thus, using this set of markers, populations can be ascribed to one of these species, but not individuals by themselves.
AFRIKAANSE OPSOMMING: As deel van 'n natuurbewarings program, word daar in hierdie studie twee spesies van vis ondersoek was in kontak met mekaar gekom het op onnatuurlike wyse. Hierdie twee visspesies vanuit die CICHLIDAEfamilie (Oreochromis mossambicus en 0. ni/oticus) kan hibridiseer wanneer hul saam voorkom, maar dit is ook bekend dat die uitheemse O. ni/oticus die inheemse O. mossambicus kan bedreig in terme van leefruimte, kos en broeispasie. Om die voorkoms van hibriede tussen die twee spesies te ondersoek in Suider Afrika se varswater opvangsgebiede, is dit baie belangrik om individue baie akkuraat te identifiseer. In hierdie poging om genetiese merkers te vind wat die twee spesies van mekaar onderskei, het ons 20 mikrosateliet di-nulkleotied (CAn) herhalende volgordes op verskillende loci ondersoek. Vyf daarvan het belowend voorgekom om as spesie spesifieke merkers te dien. Die fragmente op die vyf loci is ge-amplifiseer in 145 individue vanuit 10 populasies. Presiese groottes van die fragmente is bepaal met behulp van 'n ge-outomatiseerde DNA volgorde bepaler waarna genotiepes vir elke individu toegeken is. Tussen die twee spesies het alleel groottes oorvleuel, maar wanneer data geanaliseer word met behulp van statistiese metodes, was verskille tussen die spesies duidelik op populasie vlak. Die hibriede het intemediêr tussen die twee spesies voorgekom. Dus met behulp van hierdie stel merkers kan onderskei word tussen die twee spesies op populasie vlak, hoewel individue nie op sig self identifiseer kan word nie.
49
Laughlin, Thomas Fain. "Hypervariable DNA markers and population structure in three fish species." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-171854/.
Full text
50
Galvez, Fernando. "The toxicology and physiology of waterborne and dietary silver exposure in freshwater fish." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0034/NQ66266.pdf.
Full text