Thesis (Ph. D.)--University of Wisconsin--Madison, 1925. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.D.)--Columbia College, 1811. / Microform version available in the Readex Early American Imprints series.

No description available.

Thesis (M.D.)--University of Pennsylvania, 1805. / Microform version available in the Readex Early American Imprints series.

Weight-specific oxygen consumption of midgut gland tissue of Hemigrapsus nudus has been investigated at three levels of salinity (35%, 75% and 125% sea water), two levels of experimental temperature (5°C and 20°C) and four acute (Warburg) temperatures (5°, 10°, 15° and 20°C) in all combinations for each season (summer and winter). Metabolic-temperature curves reveal that at standard baseline conditions where the animals are held 24 hr at their respective seasonal temperature and salinity, midgut gland respiration is highest at all acute temperatures in the summer animals. Acutely measured metabolic-temperature curves for midgut gland tissue show that winter animals acclimated to their opposite seasonal conditions of temperature and salinity for 10 days demonstrate the greatest degree of acclimation. The effect of experimental temperature is statistically and biologically significant. The highest respiration rate is at 5°C. Low temperature (5°C) may provide a greater thermal stress than a high temperature (20°C) resulting in a higher rate of oxygen consumption. Experimental temperature also influences the seasonal respiratory response of midgut gland tissue to salinity. In summer animals there is no correlation of midgut gland respiration to salinity at 5°C. There is a increase in respiration rate as the osmotic gradient between the blood and medium increases at the seasonal baseline temperature of 20°C. Winter animals held at the seasonal baseline temperature of 5°C demonstrate a "V-shaped" relationship to salinity with the lowest respiratory response in 75% sea water where the gradient between the blood and medium is minimal. Animals held at 20°C increase respiration with an increase in salinity. It is suggested that the metabolic activity of midgut gland from summer animals may be related to the maintenance of a osmotic gradient between the blood and medium or alternatively to the energy demands associated with new exoskeleton formation. The proposal is put forth that midgut gland respiration in winter animals may indicate osmotic work being done to maintain the osmotic gradient between the blood and medium. The production of a urine hypotonic to the blood may also assist winter animals in regulation of blood electrolytes. The regression coefficients of weight-specific oxygen consumption as a function of body weight were not significantly different from zero at the 0.01 probability level. / Science, Faculty of / Zoology, Department of / Graduate

A structural analysis of the compound eye of Hemigrapsus nudus expands the basis of functional analysis of decapod Crustacean eyes. Contradictory evidence for disintegration of rhabdomeric microvilli in the absence of light prompted observation of H. nudus eyes after 146 days in darkness. Eyes were fixed with formalin and glutaraldehyde and post fixed with osmium tetroxide for electron and light microscopy. Light- dark-adapted eyes were also observed with hot water fixation and paraffin embedment. The eye of H. nudus is typical of decapod Crustacean compound eyes. Corneagenous cells underlie the transparent cuticle cone cells secrete the composite crystalline cone which contacts the rhabdom proximally. The single fused rhabdom is composed of layers of microvilli from two groups of retinular cells. The layers are oriented at right angles to each other, and perpendicular to the optic axis of the ommatidium. A presumptive four-lobed eighth retinular cell makes up the distal end of the rhabdom. Distal, proximal and reflecting retinal pigments are located in the distal pigment cells, retinular cells and tapetal cells, respectively. Distal and proximal pigments surround the rhabdom during light-adaptation, and withdraw during dark-adaptation. Reflecting pigment is found above the basement membrane in light-adapted eyes and below it in dark-adapted eyes. The crystalline cone may change length during light- and dark-adaptation. Prolonged darkness does not cause disintegration of the rhabdomeric microvilli. H. nudus lives in conditions of dim illumination. The fused, layered rhabdom is an efficient mechanism of light absorption. Internal reflection within the rhabdom is enhanced by the palisade and further increases light absorption. Functional units exist within the ommatidium. Mutually perpendicular rhabdomeric layers suggest intraretinal polarized light perception. Eighth retinular cells may respond individually to light focused on the distal rhabdom by the dioptric apparatus in mosaic image formation.

Thesis (M.S.)--Humboldt State University, 2008. / Includes bibliographical references (leaves 55-57). Also available via Humboldt Digital Scholar.

Thesis (M.S.)--The University of North Carolina at Greensboro, 2008. / Directed by Malcolm Schug; submitted to the Dept. of Biology. Title from PDF t.p. (viewed Aug. 14, 2009). Includes bibliographical references (p. 40-47).

Graduation date: 1967

Qualitative and quantitative analysis of anthocyanins and other phenolic compounds from a purple corn extract was performed. The purple corn extract had cyanidin-3-glucoside, pelargonidin-3-glucoside, peonidin-3-glucoside and its respective acylated anthocyanin-glucosides. Cyadinin-3glucoside was the main constituent (44.4 ?? 4.7%) followed by the acylated cyanidin-3-glucoside (26.9 ?? 8.0%). Other phenolic compounds present in the purple corn corresponded to protocatechuic acid, vanillic acid, and p-coumaric acid. In addition, quercetin derivatives, a hesperitin derivative and pcoumaric and ferulic acid derivatives were found. Fractionation of phenolic compounds yielded two main fractions, an anthocyanin-rich water fraction (WF) and an ethyl acetate fraction (EAF). Evaluation of antimutagenic activity in both fractions revealed higher antimutagenic activity in the ethyl acetate fraction compared to the anthocyanin-rich fraction. On the other hand, antioxidant activity of the anthocyanin-rich fraction was higher compared to the ethyl acetate fraction. Further fractionation of the anthocyanin-rich fraction in a Toyopearl HW40 gel permeation column yielded five sub-fractions which showed no difference in antimutagenic activity except for the water sub-fraction WF-V. All the sub-fractions were active as antimutagens and antioxidants. Further fractionation of the ethyl acetate fraction yielded four sub-fractions that showed to be active as antimutagens and antioxidants. Ethyl acetate sub-fraction EAF-IV was the most active as an antimutagen. HPLC-DAD characterization of that sub-fraction revealed mainly the presence of a quercetin derivative with UV-visible spectral characteristics similar to rutin but with a little longer retention time. The mechanism of antimutagenic action by the phenolic compounds present either in the anthocyanin-rich fraction or the ethyl acetate fraction and sub-fraction EAFIV seems to be a contribution of a direct action on the enzymes involved in the activation of the mutagen and to the scavenging activity of the mutagen nucleophiles, as demonstrated by our assays.