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In past attempts, the experimental germination of the seeds of Euonymus americanus L. in vitro has had little success. However, treatment of seeds with rumen fluid containing viable microflora has been successful in stimulating germination. In the presence of the cellulolytic rumen bacterium. Clostridium cellobioparum ATCC 15832, seeds of E. americanus were stimulated to germinate. Subsequent studies were designed to determine whether the bacterium synthesized a cellulolytic enzyme responsible for initiating germination. The cell-free endocellulase from C. cellobioparum was demonstrated to induce germination of the seeds. To support the hypothesis that endocellulase from C. cellobioparum was responsible for triggering germination, a 1, 4- β – endo-glucanase (EC 3.2.1.4) from Pennicillium funiculosum was used to treat the seeds. Also, Ruminococcus flavefaciens strain FD-1 was found to initiate germination of E. americanus seeds. Thus, cellulose activity is indicated in the degradation of the testa of the seed allowing imbibition and germination.

Thesis (M.S.)--University of Wyoming, 2006. / Title from PDF title page (viewed on Nov. 13, 2007). Includes bibliographical references (p. 73-76).

Thesis (Ph.D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaves 190-202).

Thesis (Ph.D.)--Drexel University, 2008. / Includes abstract and vita. Includes bibliographical references (leaves 155-172).

Thesis (Ph.D.)--Drexel University, 2008. / Includes abstract. Includes bibliographical references (leaves 76-83).

Thesis (Ph. D.)--Drexel University, 2005. / Includes abstract and vita. Includes bibliographical references (leaves 95-108).

Thesis (Ph. D.)--Drexel University, 2006. / Includes abstract and vita. Includes bibliographical references.

Spatial patterns in seagrass stoichiometry from the Florida Keys suggest that benthie community responses to eutrophication may significantly differ from nearshore habitats to the offshore reef tract. A 14 month in-situ nitrogen and phosphorus fertilization experiment was carried out to assess the consequences of coastal nutrient enrichment in the upper Florida Keys. The responses of benthic communities to nitrogen and phosphorus enrichment varied appreciably between nearshore and offshore habitats. Offshore seagrass beds were strongly limited by nitrogen, as suggested by highly significant increases in seagrass morphology, biomass, abundance, and growth rates in response to added nitrogen but not to phosphorus. Nearshore sites were affected by simultaneous nitrogen and phosphorus addition, where significant increases were found for seagrass abundance and growth, macroalgae abundance, epiphyte loads, and sediment microalgae. This investigation emphasized the importance of nutrient supply in determining benthic community composition in the upper Florida Keys.

Melanocytes are the pigment producing cells found in our skin, the hair follicles and the inner ear. They are derived from neural crest progenitor cells that also give rise to sensory and sympathetic neurons, the Schwann cells of the peripheral nervous system as well as adrenomedullary cells. In vitro studies have shown that the ErbB neuregulin receptors are present in differentiated melanocytes and melanocyte precursor cell lines. To investigate the function of the neuregulin signaling pathway on melanocyte development in vivo I used an ErbB3 knock out mouse also carrying the LacZ reporter gene. The number of melanoblasts was significantly reduced at E10.5 but showed no differences at El 1.5 or E12.5 when compared to controls. A survival assay indicated that the initial decrease in melanocyte precursor numbers is not due to increased cell death. These results indicate that this pathway affects early melanocyte precursors.