Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisors: Ulhas P. Naik, Dept. of Biological Sciences and Brian J. Bahnson, Dept. of Chemistry and Biochemistry. Includes bibliographical references.

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.