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The Scattering Of Gas Phase Molecules Andvan Der Waals Clusters From Surfaces, John Norman Beauregard

Doctoral Dissertations

The interaction of gas phase species with surfaces plays an important role in a myriad of processes such as heterogeneous catalysis, corrosion and the etching of semiconductor surfaces in the microelectronics industry. Thus, the study of gas-surface interactions has become a field of intense research. In this dissertation, we present the results of a computational study of the scattering of gas phase molecules and van der Waals clusters from surfaces. We have used molecular dynamics calculations which allow for the examination of the microscopic details of gas-surface scattering.

In this work we study four distinct systems. In Chapter I the …

Genetic And Molecular Analyses Of Host Symbiotic Genes And An In Vitro Regeneration System For Cicer Arietinum L, Vijayashri Ganapathy Paruvangada

Doctoral Dissertations

Ineffectively nodulating plant mutants PM405B, PM638A, and PM796B were used in molecular/genetic analyses of root nodule formation in chickpea. To establish the mode of inheritance of the mutant nodule phenotype in chickpea mutant PM638A, reciprocal crosses were made between PM638A and wild-type ICC640. The F$\sb2$ segregation data fit a 3 mutants: 1 wild-type monohybrid phenotypic ratio, indicating that ineffective nodulation is due to a monogenic dominant, nuclear mutation, tentatively designated as "Rn$\sb7$". Segregation analysis of F$\sb3$ progeny confirmed this model.

Early (ENod2) and late (Lb) nodulin cDNAs were used as heterologous probes to identify and study the expression of corresponding …

Regulation Of The Yeast Transcriptional Activator Adr1, W James Cook

Doctoral Dissertations

Glucose repression of the ADH2 gene from Saccharomyces cerevisiae is mediated by the abundance and activity of the transcriptional activator ADR1. The focus of this dissertation is to characterize the mechanisms by which glucose controls the ability of ADR1 to activate ADH2 transcription.

Glucose results in a two-fold decrease in the steady state levels of ADR1 mRNA. This glucose-dependent reduction in steady state ADR1 mRNA was shown to be due to an increased rate of ADR1 mRNA degradation. The unusually long, 510 nucleotide 5$\sp\prime$ untranslated region of the ADR1 mRNA appeared to mediate this glucose-dependent ADR1 mRNA decay.

To better …

Insertion Sequence Elements In Yersinia: Nucleotide Sequence Of Is100 Of Yersinia Pestis, Stephen Dale Torosian

Doctoral Dissertations

The World Health Organization classified (Williams, 1983) Y. pestis as Y. pseudotuberculosis subsp. pestis on the basis of DNA homology, yet the two organisms cause markedly different disease. Portnoy and Falkow (1981) reported IS100 to influence the virulence of Y. pestis. IS100 was shown to be found in Y. pestis but not Y. pseudotuberculosis.

IS100 from Y. pestis was sequenced and shown by sequence analysis to fulfill the requirements of being an IS element. pIS1C, an 821 bp fragment of IS100 was transferred to Y. pseudotuberculosis Trp-Ca-, resulting in the ability of the cells to ferment rhamnose and delayed production …

Characterization Of Activation And Inhibitory Regions In The Adr1 Transcriptional Regulator, Dan Chase

Doctoral Dissertations

The regulation of the ADH2 gene from the yeast Saccharomyces cerevisiae is carbon source-dependent. Expression of ADH2 requires the activity of the transcriptional activator ADR1. This dissertation addresses three separate aspects of the regulation of ADR1 activity.

We have identified eleven additional ADR1$\sp{c}$ mutations which allow ADH2 to partially escape glucose repression. These eleven new mutations cluster to one region of the ADR1 peptide between amino acids 227 and 239, previously identified by four other ADR1$\sp{c}$ mutations. These are the only mutations in ADR1 which have been isolated by virtue of their ability to activate ADH2 transcription under repressed conditions. …