Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Edward E. Schmidt. Includes bibliographical references (leaves 71-83).

Thesis (Ph. D.)--Washington State University, May 2007. / Includes bibliographical references.

Thesis (M.S. in Biology) -- University of Dayton. / Non-Latin script record. Title from PDF t.p. (viewed 10/06/09). Advisor: Mark Nielsen. Includes bibliographical references (p. 41-43).

Th. 3e cycle--Pharm.--Paris 5, 1981. N°: 25.

No description available.

Secondary metabolism occurs after the main growth phase in Streptomyces. A 'transition phase' occurs to remodel global patterns of gene expression at the onset of physiological and developmental differentiation. Many different signals influence this transition phase, integrating, for example, information on nutritional status, growth rate, and stress responses. Several pleiotropic transcription factors that regulate the transition phase have been identified, but aspects of epigenetic control of gene expression are not well understood. This study focused on the characterisation of a novel gene sco2075 in S. coelicolor encoding a protein that combines a histone-like domain with a conserved DksA-like domain, the latter considered a ppGpp cofactor. The protein is important for integrating responses to both oxidative and osmotic stresses. The sco2075- mutant strain is sensitive to oxidative stress at least in part due to reduced induction of the alternative sigma factor sigmaR. SCO2075, similarly to E. coli DksA, may play a possible role in the liberation of core RNA polymerase to bind alternative sigma factors such as sigmaR. In addition DSCO2075 has an altered topological profile of a reporter plasmid under osmotic stress, showing little alteration in negative supercoiling when compared to the significant increase in wildtype. DSCO2075 also has a reduction in aerial hyphae and a possible reduction in actinorhodin production when grown with osmolyte. The histone-like domain of SCO2075 binds DNA non-specifically. SCO2075 expression appears to coincide with diffused FtsZ expression prior to Z-ring formation when SCO2075 appears to become nucleoid associated. Analysis of pre-spore compartment lengths showed SCO2075 is one of several nucleoid associated proteins involved in nucleoid compaction during aerial hyphal erection and sporulation. Absence of sco2075, however, does not affect the production of unigenomic spore chains. Finally, over-expression of SCO2075 suppresses defects in secondary metabolism of a relA mutant affected in ppGpp synthesis. SCO2075 could potentially be a new type of regulator, likely acting as a node to integrate stress and physiological cues by modulating DNA topology/compaction and RNA polymerase activity.

No description available.

Phosphines and phosphites have been investigated as ligands to tetraphenylporphinato iron(II) (FeTPP) by spectrophotometric titration in tetrahydrofuran. A least squares method for determination of the equilibrium constants K1 and K2 (K1 and K2 correspond to the sequential binding constants for the formation of FeTPPL and FeTPPL2, respectively) was developed. This method eliminates the errors associated with fundamental assumptions intrinsic to the more conventional Hill plot. The visible spectrum of the 5-coordinate complex, FeTPPL, was also determined for each ligand. The equilibrium constants obtained are: {L(logK1, logK 2)}, PMe3 (5.53, 4.60); PEt3 (5.61, 4.30); P(n- Bu)3 (6.13, 5.02); P(OEt)3 (3.87, 2.82); P(O-i-Pr)3 (3.28, 1.13). The equilibrium constants are dependent upon steric bulk, σ-basicity and π-acidity.

Young adults often outperform older adults on tests of associative memory, however, the source of this age-related associative memory deficit is still under debate. There are two main non-mutually exclusive hypotheses: 1) impaired binding processes (i.e. creating and retrieving links between units of information) and; 2) impaired strategic processes (i.e. cognitive control processes that support encoding and retrieval). Although both components are thought to contribute uniquely and interact to support associative memory, they have rarely been studied together. The primary goal of this dissertation is to further characterize associative memory deficits in healthy aging by measuring and controlling binding and strategic processes. Specifically, in this series of three experiments, we studied these two components concurrently by varying the level of demands on binding (i.e. comparing memory for different types of associations) and strategic processes (i.e. varying demands on self-initiated processes). A total N of 97 young adults and 94 older adults studied lists of object-pairs and object-location pairs under intentional encoding conditions. Demands on self-initiated processes were manipulated by increasing the number of foils at test (Experiment 1: 4 alternative forced-choice (AFC), vs. Experiment 2 & 3: 20AFC), and by providing strategy instructions in Experiment 3. We measured the production of strategies with trial-by-trial self-report. In all three experiments, we found that young adults outperformed older adults on object-object memory, but not on object-location memory. Older adults were just as proficient as young adults in generating strategies at study. This remained true even when demands on self-initiated processes increased. However, we found in all three experiments that young adults had greater strategy effectiveness (i.e. accuracy on pairs encoded with a strategy) on the object-object test. In contrast, performance on the object-location task was found to be less related to strategies. Our findings suggest that not all associations are equally affected by aging and that even when strategy production is equivalent between age groups older adults can still be impaired on associative memory. The secondary goal of this dissertation was to explore the contribution of individual variability in age, general cognitive functioning, meta-memory and executive functioning on object-object and object-location memory, strategy production, and strategy effectiveness. Our results highlight the important contribution of executive functioning over and above any effects of age in explaining age-related associative memory decline.