Thesis (Ph. D.)--University of Illinois, 1917. / Vita. "Contributions from the Zoological laboratory of the University of Illinois under the direction of Henry B. Ward, no. 129. "Reprinted from the Transactions of the American microscopical society, vol. 38; 43-170." Bibliography: p. 111-115.

Thesis (Ph. D.)--University of Illinois, 1917. / Vita. "Contributions from the Zoological laboratory of the University of Illinois under the direction of Henry B. Ward, no. 129. "Reprinted from the Transactions of the American microscopical society, vol. 38; 43-170." Bibliography: p. 111-115.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Biological Sciences, 2007. / Includes bibliographical references.

No description available.

Hookworm infection caused by Ancylostoma duodenale or Necator americanus is a significant global health threat, causing chronic anemia, malnutrition, developmental delay, enteritis, and increased susceptibility to non-parasitic diseases. One of the most prevalent of the neglected tropical diseases, hookworm infection affects almost 1 billion people worldwide, particularly in developing countries. Current methods for diagnosis and treatment of hookworm infection are largely the same as they have been for the past century. However, several recent advances in the molecular characterization of hookworm virulence factors now provide researchers with an improved understanding of disease pathogenesis, potential targets for treatment and novel antigens for vaccine development. In order to better understand hookworm pathophysiology and immunology in human populations, a comprehensive, cross-sectional immunoepidemiologic survey of approximately 200 villagers in a remote area of the Peruvian Amazon was conducted. Hookworm prevalence rates were found to approach 40% by microscopic diagnosis. Additionally, molecular speciation techniques showed that both A. duodenale and N. americanus are endemic to this region. Reagents from a laboratory model of hookworm disease were then utilized to characterize human immune responses to hookworm specific antigens. By studying the immunoepidemiology of an endemic community we have found that a laboratory strain of hookworm, Anyclostoma ceylanicum, is a useful tool for describing species specific immune responses to disease. This work lays the foundation for future development of improved hookworm diagnostic techniques by molecular and immunologic methods.

Os filamentos branquiais da lagosta Americana, Homarus americanus, foram dissociados em solução salina fisiológica e os diversos tipos celulares separados em gradiente de 30, 40, 50 e 80% de sacarose através de centrifugação de alta velocidade. As células provenientes de cada solução de sacarose foram incubadas em 65Zn2+ visando caracterizar a tomada de zinco para cada tipo celular. A caracterização do acúmulo de zinco em cada célula foi investigada na presença e ausência de 10mM de cálcio (CaCl2), variadas concentrações de NaCl e pH, presença de 100 µM de verapamil, nifedipina (inibidores de canais de Ca2+) e ionóforo de cálcio, A23187. O influxo de 65Zn2+ foi descrito pela cinética de Michaelis-Menten nas concentrações de zinco variando de 1-1000 µM.. O cálcio externo não afetou o transporte de Zn para as células presentes no gradiente de 30% a 50% de sacarose, mas atuou como estimulador para as células em gradiente de 80% de sacarose. O cálcio reduziu o Km e a velocidade máxima de transporte (Vmax) para as células de 30% de sacarose, enquanto duplicou aparentemente a velocidade máxima de transporte para as células provenientes do meio em 80% de sacarose. Os resultados sugerem que o cálcio, sódio e prótons entram nas células branquiais através de um canal para cátion com ampla especificidade. Diferenças observadas no transporte de zinco em relação aos diferentes tipos de células aparentemente estão relacionadas com as diferentes taxas de afinidade de cada transportador em cada tipo celular. O transporte de 65Zn2+ também foi estudado em filamentos branquiais isolados e intactos, demonstrando propriedades de transporte muito parecidas com as observadas pelas células em gradiente de 80% de sacarose. Os resultados sugerem que a tomada de Zn se dá por processo de transporte na membrana apical das brânquias. Um modelo experimental para o transporte de Zn em células de brânquias de lagostas é apresentado. / Gill filaments of the American lobster, Homarus americanus, were dissociated in a physiological saline and separated into several cell types on a 30, 40, 50, and 80% sucrose gradient. Cells from each sucrose solution were separately resuspended in physiological saline and incubated in 65Zn2+ in order to assess the nature of metal uptake by each cell type. Characteristics of zinc accumulation by each kind of cell was investigated in the presence and absence of 10 mM calcium (CaCl2), variable NaCl concentrations and pH values, and 100 µM verapamil, nifedipine (calcium channel inhibitors), and the calcium ionophore, A23187. 65Zn2+ influxes were hyperbolic functions of zinc concentration (1-1000 µM) and followed the Michaelis-Menten kinetics. External calcium was neutral to cells from 30% to 50% sucrose, but stimulatory for cells from 80% sucrose. However, calcium reduced both apparent zinc binding affinity (Km) and maximal transport velocity (Jmax) for 30% sucrose cells, while doubling the apparent maximal transport velocity for 80% sucrose cells. Results suggest that calcium, sodium, and protons enter gill epithelial cells by way of an endogenous broad-specificity cation channel and trans-stimulate metal uptake by a plasma membrane carrier system. Differences in zinc transport observed between gill epithelial cell types appear related to apparent affinity differences of the transporters in each kind of cell. Low affinity cells from 30% sucrose were partially inhibited by calcium, while high affinity cells from 80% sucrose were stimulated. 65Zn2+ transport was also studied by isolated, intact, gill filament tips. These intact gill fragments generally displayed the same transport properties as did cells from 80% sucrose and provided support for metal uptake processes being an apical phenomena. A working model for zinc transport by lobster gill cells is presented.

Os filamentos branquiais da lagosta Americana, Homarus americanus, foram dissociados em solução salina fisiológica e os diversos tipos celulares separados em gradiente de 30, 40, 50 e 80% de sacarose através de centrifugação de alta velocidade. As células provenientes de cada solução de sacarose foram incubadas em 65Zn2+ visando caracterizar a tomada de zinco para cada tipo celular. A caracterização do acúmulo de zinco em cada célula foi investigada na presença e ausência de 10mM de cálcio (CaCl2), variadas concentrações de NaCl e pH, presença de 100 µM de verapamil, nifedipina (inibidores de canais de Ca2+) e ionóforo de cálcio, A23187. O influxo de 65Zn2+ foi descrito pela cinética de Michaelis-Menten nas concentrações de zinco variando de 1-1000 µM.. O cálcio externo não afetou o transporte de Zn para as células presentes no gradiente de 30% a 50% de sacarose, mas atuou como estimulador para as células em gradiente de 80% de sacarose. O cálcio reduziu o Km e a velocidade máxima de transporte (Vmax) para as células de 30% de sacarose, enquanto duplicou aparentemente a velocidade máxima de transporte para as células provenientes do meio em 80% de sacarose. Os resultados sugerem que o cálcio, sódio e prótons entram nas células branquiais através de um canal para cátion com ampla especificidade. Diferenças observadas no transporte de zinco em relação aos diferentes tipos de células aparentemente estão relacionadas com as diferentes taxas de afinidade de cada transportador em cada tipo celular. O transporte de 65Zn2+ também foi estudado em filamentos branquiais isolados e intactos, demonstrando propriedades de transporte muito parecidas com as observadas pelas células em gradiente de 80% de sacarose. Os resultados sugerem que a tomada de Zn se dá por processo de transporte na membrana apical das brânquias. Um modelo experimental para o transporte de Zn em células de brânquias de lagostas é apresentado. / Gill filaments of the American lobster, Homarus americanus, were dissociated in a physiological saline and separated into several cell types on a 30, 40, 50, and 80% sucrose gradient. Cells from each sucrose solution were separately resuspended in physiological saline and incubated in 65Zn2+ in order to assess the nature of metal uptake by each cell type. Characteristics of zinc accumulation by each kind of cell was investigated in the presence and absence of 10 mM calcium (CaCl2), variable NaCl concentrations and pH values, and 100 µM verapamil, nifedipine (calcium channel inhibitors), and the calcium ionophore, A23187. 65Zn2+ influxes were hyperbolic functions of zinc concentration (1-1000 µM) and followed the Michaelis-Menten kinetics. External calcium was neutral to cells from 30% to 50% sucrose, but stimulatory for cells from 80% sucrose. However, calcium reduced both apparent zinc binding affinity (Km) and maximal transport velocity (Jmax) for 30% sucrose cells, while doubling the apparent maximal transport velocity for 80% sucrose cells. Results suggest that calcium, sodium, and protons enter gill epithelial cells by way of an endogenous broad-specificity cation channel and trans-stimulate metal uptake by a plasma membrane carrier system. Differences in zinc transport observed between gill epithelial cell types appear related to apparent affinity differences of the transporters in each kind of cell. Low affinity cells from 30% sucrose were partially inhibited by calcium, while high affinity cells from 80% sucrose were stimulated. 65Zn2+ transport was also studied by isolated, intact, gill filament tips. These intact gill fragments generally displayed the same transport properties as did cells from 80% sucrose and provided support for metal uptake processes being an apical phenomena. A working model for zinc transport by lobster gill cells is presented.

Riparian ecosystems are disproportionately biodiverse and vital to many taxa despite their scant footprint on the landscape. Yet globally they are also under the greatest human-caused threats. The loss of habitat is the greatest driver of species declines, but fragmentation may also significantly impact populations by creating barriers to dispersal. Effective conservation requires an informed understanding of species' threats and capabilities, though it is unclear whether the increasing fragmentation of riparian woodland in western North America is affecting dispersal patterns of riparian breeding birds. Research suggests long distance migrants may be less impacted than resident species, though previous genetic research on the threatened western population of the yellow-billed cuckoo (Coccyzus americanus), a long-distance Neotropical migrant and obligate riparian breeding bird, suggests local structuring among isolated western populations. There is also interest in using more informative markers to assess genetic differentiation between eastern and western yellow-billed cuckoos. Despite limited differentiation found in mitochondrial sequences between eastern and western cuckoos, analysis of microsatellite markers is expected to reveal significant population structuring. Comparing 14 polymorphic microsatellite loci among seven separate populations in the west, and between western and eastern samples, I found limited population structuring, suggesting sufficient dispersal is occurring to maintain gene flow, both among isolated western, and between western and eastern populations. I found lower than expected heterozygosity across the range, possibly due in part to higher rates of inbreeding experienced by small populations, though the results were clouded by a high number of estimated null alleles downward-biasing estimates of heterozygosity. To test the accuracy of the microsatellites and measure scoring error, I compared microsatellites and mitochondrial sequences in nesting groups sampled from high-density restoration sites on the lower Colorado River. To identify the nesting males and females, I modified a universal avian sexing protocol, optimizing it for yellow-billed cuckoos. I calculated a scoring error rate of 2.12%, 0.91% not explained by null alleles. I also confirmed a relatively high rate of conspecific nest parasitism, with the nesting male apparently fathering the parasitic young in many cases. This is the first assessment of the relationships among breeding adults and nestlings of this species. With more nests providing more egg-dumping opportunities, the productivity of parasitic females should increase with larger populations of nesting cuckoos. Restoring more large patches of functional riparian woodland, to support multiple nesting pairs, could help to recover this declining population.

Kentucky, USA, is the site of recent natural recolonization by the American black bear (Ursus americanus); however, bears are rarely observed outside the Cumberland Mountains along the state‘s southeastern border. I examined the influence of roads in constraining the distribution of this population by altering animal space use and movement. I identified patterns of road avoidance and road crossing using data from Global Positioning System collars worn by 28 adult bears (16M, 12F), and described road mortality trends using 27 roadkill events. Bears avoided roads at the home range and landscape scale, primarily crossed low-traffic roads, and crossed in sites that minimized detection by humans. Males displayed more evidence of road avoidance than females, but females crossed roads more selectively than males. Bears were most often killed on high to moderate traffic roads, and in areas less forested than expected. Roadkill and road crossing sites bore different attributes. The results of my study support previous findings that space use near roads and road crossing reflect a tradeoff between the risks of road mortality and human harassment, and the benefits of access to habitat, mates, and anthropogenic food. Road-mediated restriction of black bear space use and movement is indicated.

Historically, black bears occurred throughout Mississippi but by 1932, <12 bears remained. Repatriation in neighboring states and conservation efforts in Mississippi have led to the recolonization of at least 2 subspecies (U. a. luteolus and U. a. americanus) of black bears in the state. I compiled available data to provide a synthesis of the history, current status, and management of black bears in Mississippi. Additionally, I used global positioning data collected from radio collared bears to determine the influence of distance to source population, cover type, distance to roads, distance to water, wetland reserve program areas, and human population density on black bear resource selection at various spatial scales. I studied characteristics of space use and resource selection of recolonizing bears in the Mississippi Alluvial Valley (Delta). I assessed the influence of environmental parameters at the female core annual home-range (using 50% kernel density estimator) and male and female seasonal and annual home-ranges (95% kernel density estimator). Distance to source population and distance to roads had significant influence at the core female home-range scale. I found a sex-based difference in annual and seasonal home-ranges. I also found that bears exhibited response to and selection for specific resources with an affinity toward hardwood stands, particularly young-aged hardwoods. My research illustrates the importance of analyzing resource selection at multiple scales to gain a full understanding of parameters that influence the recolonization of a bear population.