• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 16
  • 12
  • Tagged with
  • 28
  • 28
  • 7
  • 6
  • 6
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A molecular dissection of the mating system of the Dungeness crab, Cancer magister (Brachyura:Cancridae), with observations on mating behavior /

Jensen, Pamela C. January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 95-104).
2

Measurement of dimethylamine and trimethylamine in Dungeness crab, Cancer magister

Gulan, Michael Peter 06 February 1973 (has links)
A rapid gas liquid chromatographic method was adapted to processed Dungeness crab for the determination of basic and neutral volatiles. Methylamine, dimethylamine, and trimethylamine were measured in processed Dungeness crab for the first time. Generally, the range for trimethylamine was 42 ppm for frozen crab to 700 ppm for iced crab. Low levels of dimethylamine were found in iced and frozen samples whereas higher levels (33-71 ppm) were found in canned and iced-canned samples. Ammonia, methyl sulfide, acetaldehyde, acetone, diacetyl, benzene, and toluene were also identified in processed Dungeness crab for the first time. / Graduation date: 1973
3

Osmotic and ionic regulation in the Dungeness crab, Cancer magister (Dana)

Alspach, George Samuel Jr 28 January 1972 (has links)
Osmotic and ionic regulation was studied in the Dungeness crab, Cancer magister, after acute exposure to a range of five salinities from 25% to 125% sea water (100% = 32%). Blood, urine and muscle tissue were sampled at 24 and 48 hours after exposure. Analyses were made of blood and urine osmotic concentrations, as well as blood and urine sodium, potassium, calcium, and chloride ion concentrations. Data were also obtained for these ions and the total amino nitrogen (ninhydrin positive substances) in muscle tissue from crabs at the experimental salinities. Measurements of muscle extracellular space (interfiber water) and blood volume were determined with inulin-C¹⁴. In dilute sea water, blood is hyperposmotic to the medium but remains isosmotic at 100% sea water. Urine is slightly blood hypoosmotic over the salinity range. Hyperregulation is also demonstrated for the blood cations: sodium, potassium, and calcium. Blood chloride, however, is weakly regulated and the blood:medium gradient is low. Urine cation concentrations are blood hypoionic in the salinities of 75% and 100% sea water compared to 25% and 50% sea water where they are isoionic, Urine chloride is isoionic in 75% and 100% sea water, but blood hyperionic in 25% and 50% sea water. Increases in tissue water content as well as muscle extracellular (interfiber water) space occur when crabs are placed in dilute sea water. The inulin extracellular space is 7.3% in 100% sea water and this is lower than the chloride spaces (18%). Reductions in muscle ions concentrations and free amino nitrogen compounds occur. The blood:tissue gradient for potassium indicates intracellular regulation of this ion, while no regulation of sodium and chloride is found. Decreases in free amino nitrogen compounds in dilute sea water do not contribute significantly to decreases in cell volume through loss of osmotically active nonelectrolytes in the muscle. In concentrated sea water (125%), there is some indication of blood hypoosmotic regulation while urine is regulated blood hypoosmotic, The pattern of blood sodium, potassium and chloride regulation suggests slight hypoionic regulation. Urine sodium and potassium are significantly blood hypoionic, while urine chloride is isoionic. Muscle tissue in crabs at 125% sea water indicate decreases in tissue water content, muscle sodium and muscle chloride in comparison to controls. Muscle potassium is regulated. Large increases in free amino nitrogen compounds are noted in muscle from crabs at this stress, and appear to indicate intracellular compensation for the cells to tolerate increased osmotic concentration. / Graduation date: 1972
4

An evaluation of the use of mating marks as an indicator of mating success in male Dungeness crabs /

Ainsworth, Justin C. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 66-68). Also available via Humboldt Digital Scholar.
5

Gluconeogenic adaptations in Cancer Magister

Guderley, Helga E January 1976 (has links)
The periodic requirement for a new chitincus excskeleton imposes a large biosynthetic lead on the metabolism of crustaceans, with the hypodermis facing the brunt of the load. Since the freshly molted animal is highly susceptible to predation, the mechanisms for efficient gluccnecgenesis in support of chitin synthesis are of definite survival value to the organism. Measurements of enzyme activities in the hypodermis , gill and muscle of Cancer magisrter indicate that the hypodermis and muscle undergo considerable metabolic changes during the melt cycle. Freshmolt hypodermis shows elevated specific activities of both the gluconeogenic and the glycolytic enzymes, while freshmolt muscle shows decreased levels of the glycolytic and increased levels of the gluconeogenic enzymes. Hypodermis maintains a highly gluconeogenic orientation throughout the melt cycle. Phosphoglycerate kinase is considered to be one of the bifuncticnal enzymes in the glycolytic pathway, but the kinetic characteristics of the previously studied enzymes are ill suited for function in a gluconeogenic system. Since the inter melt and freshmolt muscle and hypodernis present a variety of metabolic poises (i. e. ranging 'from highly gluconeogenic tc highly glycolytic), I studied the control of phos|lidglycerate kinase in these tissue,s:. I found that the inte^0^^iusc 1 e enzyme shows kinetics much like those of the mammalian muscle and the yeast enzyme, with a high sensitivity to MgADP/ADP inhibition (MgADP Ki = 1.3 x 10⁻⁵M) and a relatively lew affinity for ATP as a substrate (Km = 2.03 x 10-⁴M). By contrast, the freshmolt hypodermal enzyme shows a considerably decreased sensitivity to Mg ADP/ADP inhibition (Mg ADP Ki = 2 x10-⁴M) and a considerably increased affinity for ATP (Km = 6.8 x 10-⁵M). The freshmolt muscle enzyme also shares these changed affinities. The intermolt hypodernal phosphoglycerate kinase shows the decreased sensitivity to Kg ADP/ADP inhibition but shares the ATP affinity of the intermolt muscle enzyme. The kinetic characteristics of the freshmolt hypodermal and muscle enzymes reduce the susceptibility of the enzymes to inhibition by MgADP and facilitate the reversal of the reaction for gluccneogenesis. The control of pyruvate kinase is integral to the control of both glycolysis and gluconeogenesis. In glycolysis, it forms the second major control site; in gluconeogenesis, it is one of the prime determinants of the rate of gluconeogenesis from lactate and amino acids. Muscle and hypodermal pyruvate kinases from Cancer magister are distinct proteins, on the basis of isoelectric points, kinetic characteristics, and thermal denaturation behavior. In contrast to the phcsphoglycerate kinase system, there are no pronounced differences between freshmolt and intermolt forms. Muscle pyruvate kinase is activated by FDP, inhibited by KgATP, arginine phosphate, Mg2citrate, tryptophan and is also sensitive to some inhibition by alanine, ⍺--glycerolphosphate, Mg-malate and ⍺- ketoglutarate. The muscle enzyme has a high affinity for PEP (Km = 0.1 mM) and the addition of 0.05 mM FDP drops the PEP Km to 0.05 mM. In comparison with other muscle pyruvate kinases, the enzyme is quite sensitive to MgATF inhibition (Ki = 1.8 mM) and shows FDP reversal of the inhibition. Arginine phosphate inhibition is competitive with ADP, and is not reversed by FDP. The reversal of the reaction accounts for only 0.5% of the forward reaction. Although high levels of ATP and arginine phosphate strongly inhibit the reaction, the inhibition is not sufficient to allow net flux through the low levels of the bypass enzymes present in the muscle of freshmolt animals. Thus, muscle pyruvate kinase has kinetic characteristics which suit it for function in the control of glycolysis, but do not allow gluconeogenic flux past the reaction locus. In contrast, hypodermal pyruvate kinase is a consplex protein capable of making large transitions between high activity during oxidation of carbohydrate substrates and virtually no activity during gluconeogenesis from lactate and amino acids. Hypodermal pyruvate kinase exists in twc conformational states, one a high affinity state (PK I) and the ether a low affinity state (PK II), PK I has a Km for PEP of 0.1 mM and a Ka for FDP of 1.3 x 10⁻⁵. PK II has a Km for PEP of 0.55 mM and a Ka for FDP of 9 x 10⁻⁸. For both forms, FDP facilitates the binding of PEP, Eofh forms are sensitive to MgATP inhibition and show FDP reversal of the inhibition, PK II is more sensitive to inhibition by alanine, serine, and Mg2citrate. For PK II, FDP alters the inhibition due to these compounds, changing the interactions between these inhibitors and both PEE and ADP. Incubation of PK II with 0.05 mK FDP produces PK I. Prolonged dialysis of PK I leads to an enzyme with the characteristics of PK II. The levels of FDP associated with PK I are higher than the levels associated with PK II. During gluconeogenesis, the FDP levels in the cell are low. This would shift the equilibrium between the two forms towards PK II. Since physiological levels of PEP, ADP, ATP, alanine, and serine limit PK II activity to less than 0.5% of maximal, considerable flux through the phosphcenolpyruvate carboxykinase and pyruvate carboxylase bypass would be feasible. The rise in FDP levels during inhibition of gluconeogenesis would shift the equilibrium in favor of PK I. This shift would immediately raise pyruvate kinase activity from less than 0.5% to around 50% of maximal activity. This, coupled with the other changes in metabolite levels during an inhibition of gluconeogenesis, would lead to a marked activation of pyruvate kinase activity. These conformational states allow rapid changes in flux through the reaction, and thus would allow flexible and responsive regulation of this important glycolytic and gluconeogenic control site. Thus, both the phcsphoglycerate kinase and pyruvate kinase present in the hypodermis of Cancer magister have special characteristics which facilitate efficient gluconeogenesis. To elucidate the possible importance of ions in regulating the activity of the above enzymes, I measured the levels of sodium, potassium, magnesium, and calcium in the muscle and hypodermis of intermolt and freshmolt animals. I found that the extracellular' space of- the hypodermis is considerably higher than that of the muscle (45% versus 12%) , but that there was no variation between intermolt and freshmolt tissue extracellular space. While freshmolt muscle sodium concentrations were significantly higher than intermolt sodium concentrations, none of the other ions showed significant differences between molt cycle stages. However, there were significant differences between the ionic concentrations in hypodermis and muscle. Hypodermis shewed higher calcium levels and lower potassium levels than muscle in both freshmolt and intermolt animals. Although icnic changes do not play a role in differential regulation of enzyme activity during the molt cycle, the ionic concentrations present in these tissues are such that the ions could set guidelines for the activity of phosphoglycerate kinase, pyruvate kinase, phosphofructokinase, and fructose diphosphatase in these tissues. / Science, Faculty of / Zoology, Department of / Graduate
6

Effects of molting and hyposalinity stress on the expression of HIF-a, molting, and immune response genes in juvenile Cancer magister /

Miller, Wyatt Austin, January 2008 (has links)
Thesis (M.S.)--University of Oregon, 2009. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 41-49). Also available online.
7

The effects of hypoxia on hemocyanin regulation in Cancer magister : a possible role for HIF-1 in crustacean responses to hypoxia /

Head, Jennifer Mary, January 2006 (has links)
Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 94-108). Also available for download via the World Wide Web; free to University of Oregon users.
8

Some economic considerations in Dungeness crab marketing

Wix, John Robert 13 December 1966 (has links)
The purpose of this study is to describe Dungeness crab marketing from the ocean floor to the ultimate consumer; to identify relations among the Oregon Dungeness crab industry, the Pacific Coast Dungeness crab industry, and the Alaska King crab industry; and to specify the relationships between fishermen's prices for Dungeness crab and levels of Oregon production1 levels of total U.S. Dungeness crab production, levels of King crab production, and King crab prices. Primary data were gathered from fishermen, processors, state fish agencies, and the Bureau of Commercial Fisheries. Secondary sources were utilized to gain general information on King crab fishing and processing. Dungeness crab is usually sold by fishermen to processors. Processors generally sell the crab through brokers to fish wholesalers, but they may also sell directly to fish wholesalers or retailers. A definite seasonal trend was found in prices received by fishermen. However, cyclical movements have a much greater impact upon absolute price levels received by fishermen. Total catch of Dungeness crab and King crab prices were found to play important roles in determining prices received by Oregon Dungeness crab fishermen. It is concluded from the analysis that: (1) an industry-wide commission is needed to advertise and promote Dungeness crab products; (2) the ocean fishing season should be opened January 1 instead of December 1 of each year; (3) processors should endeavor to expand into new marketing areas to increase demand for their products;(4) grades and quality standards should be established; and (5) further research is needed in the technological, biological, and economic aspects of Dungeness crab production and marketing. / Graduation date: 1967
9

The structure and function of hemocyanin from Cancer magister

Graham, Robert Allison January 1983 (has links)
xiii, 192 leaves : ill. ; 28 cm Notes Typescript Thesis (Ph. D.)--University of Oregon, 1983 Includes vita and abstract Bibliography: leaves 191-192 Another copy on microfilm is located in Archives
10

Effects of salinity and temperature on the respiratory physiology of the Dungeness crab, Cancer magister, during development

Brown, Anne Christine, 1962- January 1991 (has links)
Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 172-183). / Cancer magister, the Dungeness crab, occurs in different habitats during its life cycle, habitats which vary widely in the magnitude of salinity and temperature changes. Cancer magister hemocyanin also changes in structure and oxygenation properties during development. The following question was considered in this thesis: what are the effects of environmental salinity and temperature on metabolic rates, ionic and osmotic regulation and hemocyanin oxygen affinity in Q. magister during development. Metabolic rates and hemolYmph ionic and osmotic concentrations were measured in the megalopa, 1st juvenile, 5th juvenile and adult crab eight hours after acute exposure to 100% seawater (=32 ppt), 75% seawater and 50% seawater at both 10°C and 20°C. The oxygen binding properties of the whole hemolymph from these stages in 100% seawater at 10°C was determined. The effects of calcium and magnesium on the oxygen affinity of purified hemocyanin from different stages were also determined. In 100% seawater, routine metabolic rates of the four stages scale with body mass over the size range, 0.05 gm to 500 gm. The Q10 (10°C to 20°C) for the megalopa is higher in 75% seawater and 50% seawater than in 100% seawater. For the 1st juvenile, 5th juvenile and adult the Q10 values (10°C to 20°C) are independent of salinity. The megalopa, 1st juvenile and 5th juvenile are weaker regulators of hemolymph chloride, sodium and osmotic concentrations than the adult. The megalopa and adult, unlike the 1st juvenile and 5th juvenile, strongly regulate hemolymph calcium in reduced salinity. In 100% seawater hemolymph magnesium is significantly higher in the megalopa, 1st juvenile and 5th juvenile than in the adult. The oxygen affinities of whole hemolymph from the four stages are indistinguishable when adjusted for endogenous L-lactate concentrations; the Bohr coefficients are not significantly different among stages. The effect of magnesium on oxygen affinity of purified adult hemocyanin is influenced by proton concentration; the effect of calcium is independent of proton concentration. In 100% seawater, endogenous inorganic ion concentrations in the whole hemolymph of the various stages reduce the intrinsic stage specific differences in hemocyanin oxygen affinity.

Page generated in 0.1559 seconds