The design and construction of a chemiluminescence
photometer is described. The design is based on a discrete
sample system which has a number of advantages over
the previously described flow cell system and centrifugal
analyzer. The advantages include simple and inexpensive
equipment, small sample size, versatile electronic readout
system, and...
2,5-dihydroxyacetanilide epoxidase from Streptomyces LL-C10037 (DHAE I)
catalyzes the epoxidation of hydroquinone 4, to form epoxyquinone 7. DHAE I has been
purified to homogeneity, with an overall purification factor greater than 23,000. N-terminal
and internal amino acid sequences have been obtained from the purified enzyme so
that the epoxidase gene...
The loss of all deuterium labels from previous feedings of [2-²H]-,
[3,3-²H₂]-, and [2,3,3-²H₃]arginines had indicated the possible intermediacy
of β-hydroxy- and β-ketoarginine (30 and 31, respectively) in the
biosynthesis of the streptolidine portion of streptothricin F (la).
In order to confirm or refute this evidence, D,L-[2,3,3,5,5-²H₅]-
arginine (32) was...
Early studies on the biosynthesis of the quinoline quinone portion of
streptonigrin, 1, had suggested the intermediacy of novel aromatic amino
acids. In order to test this hypothesis, a series of compounds was synthesized
and tested for potential incorporation. [4-¹⁵N] 4-Aminoanthranilic acid,
4 5 a , [4-² H] 7-aminoquinaldinic acid,...
Feeding of [3-¹³C, 2-¹⁵N]arginine, 38a, unequivocally established that the β-
arginine moiety of blasticidin S, 1, was formed from α-arginine by an intramolecular
migration of the α-amino group to the β- position. Further feedings using chirally
deuteriated arginines 38e and 38f revealed that the aminomutase process occurred with
inversion of...
A novel acyl protecting group for cytosine and adenine has been prepared
from 4-( chloromethyl) benzoic acid. Reaction of the acid with morpholine produces
4-( 4-morpholinyl )methyl benzoic acid which is converted to it's acid chloride
with thionyl chloride. This may be used to acylate cytidine and adenosine under
standard...
Early studies on the biosynthesis of Sarubicin A, 1, had suggested the
intermediacy of the novel aromatic amino acid 6-hydroxyanthranilic acid,
17. To investigate the biosynthetic steps beyond 17, [¹³C-¹⁵N carboxamide]
6-hydroxyanthranilamide, 27a, was synthesized, and fed to fermentations
of Streptomyces helicus. Incorporation of 27a into 1 provided suggestive
evidence...
Two labelled arginines, DL-[2,3,3,-²H₃]arginine, 8,
and DL-[ ¹³C, 2-¹⁵N]arginine, 9, were synthesized. These
were fed to cultures of Streptomyces griseochromogenes in
order to probe the mechanism of the apparent arginine-2,3-
aminomutase reaction occurring in biosynthesis of blasticidin
S, 1. In previous studies of the enzymes lysine-2,3-
aminomutase and tyrosine-2,3-aminomutase different...
A new x-ray source capable of operating at up to 80
watts has been designed and developed, and put to use with
the Oregon State University Cylindrical Electrostatic
Analyzer. The new source produces over four times the
photoelectron intensity of its predecessor, from gaseous
samples, and accommodates a wider selection...
The core-electron ionization potentials for mono- and
di(trifluoromethyl)benzene, for chlorofluoromethanes and for
chlorine have been measured in order to give information on
the electron distribution in these molecules and to investigate
differences between the inductive effect of fluorine
and that of CF3. For trifluoromethylbenzene the measured
ionization potentials in eV...
The work presented in this thesis deals with the mechanisms by which a vibrationally excited diatomic molecule gives up its energy to a host monatomic lattice at low temperature. The vibrational lifetimes (v"=1) of the metal oxides Ba0 and A10 in their ground electronic states are studied using pulsed dual...
This thesis describes a Mossbauer effect and electron
paramagnetic resonance study of iron (III) tetraphenylporphyrinatobenzenethiolate
benzene thiol, an analog compound
for bacterial cytochrome P-450. The compound is unusual in
that it provides a model for the two ferric reaction states
of cytochrome P-450. The iron in the model compound exhibits...
A mechanism for filiform corrosion of aluminum is proposed
based on experimental evidence and the known aqueous chemistry of
the trivalent aluminum ion. Experimental methods utilized include
autoradiographs with Cl³⁶; pH paper determination of the filiform
head pH; activator concentration and activation period as they affect
filiform growth.
The pH...
Oxidative stress is recognized as an important underlying factor in the
pathogenesis of many degenerative diseases as well as normal senescence. The
free radicals, reactive oxygen species (ROS) and electrophiles produced during
oxidative stress are capable of modifying nucleic acids, lipids and proteins. There
are a variety of oxidative modifications...
The total synthesis of a highly potent cytotoxic marine natural product, phorboxazole A, is described. Both a palladium(II)-mediated and a palladium(II)-catalyzed intramolecular alkoxycarbonylation were used as key steps for the preparation of the two cis-2,6-disubstituted tetrahydropyran rings (C22-C26 and C11-C15) of phorboxazole A.
The synthesis used a convergent approach involving...
Xanthohumol [XN, (E)-6´-methoxy-3´-(3-methylbuten-2-yl)-2´,4´,4´´-trihydroxychalcone], the principal prenylated chalcone from hops, and its 2,3-dihydro- (DXN) and O6-desmethyl-2,3-dihydro- (DDXN) congeners, are of potential utility for the amelioration of metabolic syndrome; however, their complex bioactivity profiles cannot be properly studied and understood without access to appropriately produced synthetic materials.
In the first part of...
Neptunium, with its rich redox chemistry, has a special position in the chemistry of actinides. With a decades-long history of development of aqueous separation methods for used nuclear fuel (UNF), management of neptunium remains an unresolved issue because of its not clearly defined redox speciation. Neptunium is present in two,...
The photoelectron spectra of a series of halogenated
molecules have been investigated in the gas phase. Both
core-ionization energies and Auger kinetic energies were
measured to probe the nature of the interaction that holds
a core electron to the molecule.
It was found that satellite structure (shake) could be
used...
Proteins are essential to all biological systems. Proteins participate in numerous cellular processes by interacting with other proteins, other metabolites and membranes in a dynamic environment. Studying the structural and conformational properties of proteins in the solution phase is necessary to understand their protein folding and interaction dynamics. This research...
Alcoholic liver disease (ALD) continues to be one of the major public health problems in the United States and worldwide. Complicated by factors including gender, polymorphisms of alcohol-metabolizing enzymes, immunologic factors, exposures to other substances/drugs, hepatic viral infections, nutritional deficiencies, and obesity, ALD is a complex disease that requires a...
Dysfunction of mitochondria has been linked to aging and the pathogenesis of many degenerative diseases. Aside from their primary function in energy production, mitochondria are considered as a major source and target of reactive oxygen and nitrogen species (ROS/RNS) in cells as well. The mitochondrial thiol proteome is a subset...
A comparative study was made on the effect of urea denaturation
of bovine serum albumin (BSA), polyglycyl BSA and poly-L-phenylalanyl
BSA. The denaturation process was followed by ultraviolet
spectrophotometry and optical rotation.
A blue shift in the absorption maximum at 278 mμ was observed
in urea denatured proteins, In 7M...
The Farnesoid X Receptor (FXR) is a member of the nuclear receptor superfamily of transcription factors that plays a key role in the regulation of bile acids, lipid and glucose metabolisms. The regulative function of FXR is governed by conformational changes of the ligand binding domain (LBD) upon ligand binding....
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Bottom row: Average differences in deuterium percentage (D%) of seven time points
Investigating the structure-property relationships of solid state materials can help improve many of the materials we use each day in life. It can also lead to the discovery of materials with interesting and unforeseen properties. In this work the structure property relationships of newly discovered layered oxypnictide phases are presented...
Mitochondria provide energy for biological cells to function, but this process is also a source of oxygen radicals that are capable of damaging nearby proteins. Mitochondrial protein damage can eventually lead to cell death, especially in the case of heart cells, where mitochondria are present in the highest concentrations. As...
In this dissertation, I present experimental observations of multiply charged atomic ions (MCAI) generated from interactions of atomic/molecular clusters with moderately intense nanosecond laser pulses. This process is also known as Coulomb explosion (CE) and it has been extensively studied in intense laser fields using ultrashort pulses. Several prevailing theories...
A new approach to the discovery of high absorbing semiconductors for solar cells was taken by working under a set of design principles and taking a systemic methodology. Three transition metal chalcogenides at varying states of development were evaluated within this framework. Iron pyrite (FeS₂) is well known to demonstrate...
In recent decades, there has been increased attention on human exposure to, and subsequently toxicity of, Polycyclic Aromatic Hydrocarbons (PAHs). PAHs are widespread organic pollutants and some have been shown to be toxic, carcinogenic and mutagenic. This research was focused on understanding the link between global PAH emissions and lung...
Water is an absolute necessity for life as we know it. It provides a useful medium in which chemical reactions take place that allowed for the development of single cellular organisms. When combined with the evolutionary accident that was pho- tosynthesis, water became not only a useful medium chemical reactions,...
Fungi have long been a prolific source of clinically approved drugs. The antibiotic penicillin, the cholesterol lowering statins, and the immunosuppressant cyclosporine have changed the treatment of human diseases in the last century. Recently, genome analysis of filamentous fungi has revealed that the biosynthetic potential for natural product expression is...
Voltage scanning coulometry was used to study the effects of
electrode surfaces and metals on the electrochemistry of the ferric-ferrous couple and the silver ion-silver metal couple. The analytical
technique called voltage scanning coulometry is very similar to controlled
potential coulometry. The main difference is that in voltage
scanning coulometry...
It is the responsibility of humans, as environmental stewards, to monitor our impact on the environment so that efforts can be made to remediate the effects of our actions and change behaviors. To better understand our environmental footprint, sensitive and simple analytical methods are needed to quantify the contaminants that...
A novel method for detecting the peptidase activity of clinically relevant peptidases was investigated using solid-contact electrochemical polyion sensors under chronopotentiometric control. Complete instrumental control over ion-extraction was accomplished by incorporating a lipophilic electrolyte into the ion-selective membrane; the sensors had no intrinsic ion-exchange capabilities. The sensors were used to...
To determine the impact of emerging environmental contaminants on human and environmental health, quantitative analytical methods are required. Analysis of emerging contaminants is hampered by their widely varying physical-chemical properties. Therefore quantitative analytical methods must be developed to determine the behavior of emerging contaminants in environmental systems.
A quantitative analytical...
The extraction of tantalum fluoride complexes by large cationic
extractants (tetraphenylarsonium ion, TPA, and crystal violet) and
by methyl isobutyl ketone (MIBK) has been investigated as a function
of fluoride concentration using ¹⁸² Ta as tracer. Extractions by the
cationic extractants into chloroform were carried out in the absence
of...
A variety of laser spectroscopic methods are employed in this
thesis research for studies of CF₃NO, an interesting model
photodissociative system, and for investigation of low energy rotations
and vibrations of small molecules and low molecular weight clusters in
free jet expansions.
Nonradiative energy decay for electronically excited CF₃NO is...