This work presents the development of a new highly sensitive and selective chemical assay for poly(ADP-ribose) which is routinely useful for the determination of polymer levels in vivo. This method was used to carefully measure poly(ADP-ribose) levels in normal and in DNA-damaged cells. The results of these studies strongly suggest that synthesis of poly(ADP-ribose) is involved in some aspect of DNA repair. A review of the literature is presented in the introduction of this work. Poly(ADP-ribose) synthesis has been implicated in aspects of transcription, in DNA syn thesis, and in DNA repair largely based on evidence from in vitro studies. It is apparent that current methodology has not allowed the routine quantification of poly(ADP-ribose) in vivo, hence the lack of i^n vivo data concerning the function(s) of the polymer. The body of this work presents the development of two chemical methods for the quantification of poly(ADP-ribose) and the application of one of these methods to the measurement of polymer levels in normal and DNA-damaged cells. Preliminary studies are presented on the utilization of combined gas chromatography/mass spectroscopy for the selective quantification of nucleoside derivatives. A second method makes use of the unique chemistry of the polymer for quantification. The polymer …

Cyclopropanation of the unsaturated fatty acid moieties of membrane phospholipids is a commonly observed phenomenon in a number of bacterial systems. The cyclopropane fatty acids are usually synthesized during and after the transition from exponential growth to stationary phase, or under such environmental conditions as acidic culture pH, low oxygen tension or high salt concentrations. S-Adenosylmethionine, the ubiquitous methyl group donor, provides the methylene bridge carbon in the reaction catalyzed by cyclopropane fatty acid synthase. Also formed in the reaction is S-adenosylhomocysteine, a potent inhibitor of cyclopropane fatty acid synthase, which is degraded by S-adenosylhomocysteine nucleosidase. This work provides evidence for at least two modes of regulation of lactobacillic acid synthesis, the cyclopropane fatty acid formed from cis-vaccenic acid (cis-11,12-octadecenoic acid), in Lactobacillus piantarum.

The reaction of chlorodimethylvinylsilane with tertbutyllithium was investigated in the presence of several conjugated dienes. In all cases except with 2,5-dimethylfuran, [2+4] cycloadducts of a silene intermediate are obtained in hydrocarbon solvents. The presence of THF in the reaction mixture suppresses the formation of cycloadducts in favor of 1,3-disilacyclobutanes. In the reaction of dimethylethoxyvinylsilane or dimethylmethoxyvinylsilane with tert-butyllithium the main product is the 1,1-dimethyl2-neopentyl-4-(dimethylalkoxysilyl)silacyclobutane. It is concluded that lithium chloride elimination to give silene intermediates occurs in hydrocarbon solvents. In the presence of strong Lewis bases or when the leaving group on silicon is an alkoxy group, the addition reaction giving a-lithiosilanes occurs and products arising from their coupling reactions are obtained.

The enzyme 3-Hydroxy-3- Methylglutaryl Coenzyme A Reductase catalyzes the rate limiting step of hepatic cholesterol biosynthesis and is unique among the enzymes in the early part of the pathway in that it is membrane bound. This gives rise to potential regulation of the enzyme through interactions with the endoplasmic reticulum membrane. A purification procedure has been developed which consistently produces enzyme of high specific activity. In order to fully characterize the interactions between HMG-CoA reductase and the lipids in its immediate environment, HMG-CoA reductase was purified to homogeneity and shown to be a protein-lipid complex.

Article on HTP kinetics studies of the reaction of O(2(3)Pj) atoms with H2 and D2 over wide temperature ranges.

Article on the spectroscopic properties of polycyclic aromatic hydrocarbons and the effect of solvent polarity on the fluorescence emission behavior of select fluoranthene, fluorenochrysene, indenochrysene, and indenopyrene derivatives.

Article discussing an ab initio study of methane activation by group IVB imido complexes.

This article provides comments on "Fluorescent Probe Studies on the Microstructure of Polystyrene-Poly (vinylpyridine) Diblock Copolymer Film," published in 'Macromolecules,' 1992.

Article on a computational investigation of the molecular geometry and rotational barriers in ethyl methyl ether.

Article on computational studies of the potential energy surface for O(¹D) + H₂S and the characterization of pathways involving H₂SO, HOSH, and H₂OS.

This study is an investigation of the chemical vapor deposition (CVD) of aluminum and copper on fluoropolymer surfaces and the subsequent interfacial interactions.

This article discusses kinetic studies of the reaction of atomic hydrogen with trifluoroiodomethane.

This article reviews the book "Chemistry of Advanced Materials: An Overview," edited by Leonard V. Interrante and Mark J. Hampden-Smith.

Article on the enthalpies of combustion of 2-iodosobenzoic acid and 4-nitrosophenol and the dissociation enthalpy of the I-O bond.

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Article on models to predict solubility in ternary solvents based on sub-binary experimental data.

Article on a coupled-cluster study of the enthalpy of formation of nitrogen sulfide, NS.

Article on the correlation of surface tension of mixed solvents with solvent composition.

Article discussing the mathematical representation of the solubility of electrolytes in binary solvent mixtures using the Jouyban-Acree model.

This article discusses low-coordinate iron dinitrogen complexes. Understanding the interaction of N₂ with iron is relevant to the iron catalyst used in the Haber process and to possible roles of the FeMoco active site of nitrogenase.

Article on modified transition state theory and negative apparent activation energies of simple metathesis reactions and application to the reaction CH₃ + HBr + CH₄ + Br.

Article on the solubility prediction of pyrene in non-aqueous solvent mixtures using the Jouyban-Acree model.

This document includes supplemental material to an article titled "Enthalpy of solvation correlations for gaseous solutes dissolved in alcohol solvents based on the Abraham model," published in QSAR & Combinatorial Science.

Article on the enthalpy of solvation correlations for gaseous solutes dissolved in water and in 1-octanol based on the Abraham model.