Neurofilament proteins are intermediate filaments found in the neuronal cytoskeleton. Phosphorylation of these proteins is considered important for the assembly and stability of the filaments. Accurate molecular weights have been difficult to measure, largely because the high degree of phosphorylation results in M[subscript r]'S that are significantly greater than dictated...
Hop cell wall material (CWM) extracted from hop leaves (hamulus lupulus) was
purified and characterized. The total sugar content, uronic acid content and
monosaccharide composition of the CWM were determined. Galacturonic acid is the
major component in the CWM. A mixture of unsaturated oligogalacturonides were
released from purified hop CWM...
Electron-biomolecule interactions are a biologically relevant field of study
because there are several ion fragmentation techniques that have come to the forefront
in mass spectrometric analysis that involve the interaction of charged peptides and
free electrons. By studying the electron energies that cause fragmentation in neutral
amino acids, amino acid...
E. coli thioredoxin (TRX) was modified by the episulfonium ion derived from S-(2-chloroethyl)glutathione (CEG) or S-(2-chloroethyl)cysteine (CEC). The alkylation site was located at Cys-32, which was confirmed by tandem mass spectrometry. Two forms of native TRX, Oxi- and Red-TRX, and two modified TRXs, GS- and Cys-TRX, were examined by hydrogen/deuterium...
Recombinant human macrophage colony stimulating factor beta (rhm-CSFβ) is a glycoprotein that stimulates the proliferation, differentiation and survival of cells belonging to the monocyte-macrophage lineage. It contains nine inter-subunit and intra-subunit disulfide bonds and represents an excellent model system for studying disulfide bond formation during protein folding because the assembly...
Resonance Electron Capture Mass Spectrometry (REC-MS) is a sensitive
experimental technique for the study of gas-phase compounds with positive electron
affinity. This technique was used to study a class of compounds known as
baloetbylenes containing chlorine and bromine substitutions. Haloetbylenes are an
important class of compounds because ethylene is the...
My investigations of the natural products of marine algae have resulted in
the discovery of several new secondary metabolites. Bioassay-guided
fractionation led to the isolation of these new compounds and spectroscopic
analysis was utilized in their structural characterization.
Two new and potent antimitotic metabolites, curacins B and C, were
isolated...
The purpose of this study was to develop a marine bioassay
procedure using eggs and larvae of Pollicipes polymerus, a stalked
barnacle common on the west coast of North America.
A series of experiments were run to determine optimal culture
conditions for the eggs, to see if they could be...
Many climatic factors influence grape berry composition including nutrient status, water availability, biotic stress, sun exposure and temperature. Previous research examined the effects of many factors listed above and much progress has been made. It is often difficult, however, to separate effects that typically confound each other, such as sun...
Wines were made from Pinot Noir and White Riesling grapes
which had received field application rates of 2 and 4 lb./acre of the
experimental bird repellent Mesurol (methiocarb or 3, 5 dimethyl-
4(methylthio)phenylmethylcarbamate). In addition, Pinot Noir must
and press juice and White Riesling press juice were fortified with
15...
Recently, we demonstrated that a radio-frequency-free electromagnetostatic (RF-free EMS) cell could be retrofitted into a triple quad mass spectrometer to allow electron-capture dissociation (ECD) without the aid of cooling gas or phase-specific electron injection into the cell [1-2]. Subsequently, we used our RF-free EMS cell in the same instrument platform...
Full Text:
in Q-TOF
Valery G. Voinov§,†, MaxL. Deinzer§, Joseph S. Beckman§ and Douglas F. Barofsky
Recently, we demonstrated that a radio-frequency-free electromagnetostatic (RF-free EMS) cell could be retrofitted into a triple quad mass spectrometer to allow electron-capture dissociation (ECD) without the aid of cooling gas or phase-specific electron injection into the cell [1-2]. Subsequently, we used our RF-free EMS cell in the same instrument platform...
Full Text:
Q-TOF
Valery G. Voinov§,†, MaxL. Deinzer§, Joseph S. Beckman§ and Douglas F. Barofsky§
§Department
Recently, we demonstrated that a radio-frequency-free electromagnetostatic (RF-free EMS) cell could be retrofitted into a triple quad mass spectrometer to allow electron-capture dissociation (ECD) without the aid of cooling gas or phase-specific electron injection into the cell [1-2]. Subsequently, we used our RF-free EMS cell in the same instrument platform...
Recently, we demonstrated that a radio-frequency-free electromagnetostatic (RF-free EMS) cell could be retrofitted into a triple quad mass spectrometer to allow electron-capture dissociation (ECD) without the aid of cooling gas or phase-specific electron injection into the cell [1-2]. Subsequently, we used our RF-free EMS cell in the same instrument platform...
Recently, we demonstrated that a radio-frequency-free electromagnetostatic (RF-free EMS) cell could be retrofitted into a triple quad mass spectrometer to allow electron-capture dissociation (ECD) without the aid of cooling gas or phase-specific electron injection into the cell [1-2]. Subsequently, we used our RF-free EMS cell in the same instrument platform...
Recently, we demonstrated that a radio-frequency-free electromagnetostatic (RF-free EMS) cell could be retrofitted into a triple quad mass spectrometer to allow electron-capture dissociation (ECD) without the aid of cooling gas or phase-specific electron injection into the cell [1-2]. Subsequently, we used our RF-free EMS cell in the same instrument platform...
This thesis describes the chemical investigation of marine cyanobacteria collected in Madagascar and Panama with an emphasis on the isolation and structure elucidation of medicinally relevant secondary metabolites.
A collection of the marine cyanobacterium Lyngbya majuscula from the Radames Islands, Madagascar yielded two new cyclic depsipeptides, radamamides A and B,...
The unfolding of human retinoid X receptor α in the presence of the denaturant guanidine HCl was studied using stopped-flow absorbance spectroscopy. The protein's four native cysteine residues were mutated to obtain four single-cysteine mutants, each with the other three cysteine residues mutated to alanine. The thiols of these hRXRα...
Two approaches to the tricyclic core of the furanoeremophilane sesquiterpenoids are described. The first approach entails a projected Diels-Alder/retro Diels-Alder reaction of an acetylenic oxazole 64. Construction of the pivotal aldehyde 67 commenced from ketone 68. The acetyenic moiety was then introduced via a Felkin-Ahn addition of lithiopropyne to aldehyde...
The rhenium (V) complex Tp'ReO₂ (Tp' = hydrido-tris-(3,5-
dimethylpyrazolyl)borate), generated in situ from PPh₃ reduction of
Tp'Re0₃, reacts with small ring heterocycles such as epoxides and
episulf ides. The strained trans-cyclooctene ring provides an unusual
thermodynamic bias against direct atom transfer, but trans-cyclooctene
oxide still produces substantial amounts of trans-cyclooctene....
'Gala' is an apple cultivar with a distinctive aroma and flavor. 'Gala' storage season is short in regular atmosphere (RA). Controlled atmosphere (CA) extends 'Gala' storage but volatile production is reduced. 'Gala' odor-active aroma compounds were identified using Osme, a gas chromatography and olfactometry technique. Changes in aroma after RA...
In wood-plastic composites (WPCs) a compatibilizer is often used to improve
the interfacial adhesion between the hydrophilic wood filler and the hydrophobic
plastic matrix. At present, while the basic concepts of compatibilization are
understood, the optimized chemical structures of an effective compatibilizer, including
the ideal structures of the wood-binding domain...
Traditional readings of George Bernard Shaw's texts suggest that he is not a pure
Marxist socialist because of the spiritual and nationalist aspects of his vision. This thesis
attempts to confront Shaw's politics in order to demonstrate that he indeed offers a viable
socialist program. Overlaying his socialism with Louis...
Part 1:
White muscle disease (WMD), a degenerative muscle disease brought on by a deficiency of the essential trace nutrient selenium, is thought to be mediated by the protein Selenoprotein W (SeW). In its relationship with WMD, SeW, like many selenoproteins, binds to glutathione, serving some purpose in redox mechanisms...
Soybeans were grown in hydroponic solutions and in perlite to
devise procedures to measure plant mineral accumulation and
solution depletion over time. Electron emission spectrometry and
micro-Kjeldahl-autoanalyzer analytic techniques were used to
monitor mineral content of individual plants and their corresponding
solutions. An automated computer assisted system of converting
raw...
This thesis is an investigation of the natural products deriving from marine algae and cyanobacteria and has resulted in the discovery of eleven new secondary metabolites. The structure elucidations of these new molecules were performed using a variety of spectroscopic techniques. Four new macrolides were isolated and characterized from the...
Studies toward the total syntheses of highly potent cytotoxic alkaloids
including the bromopyrrole alkaloids and indole alkaloids were conducted and are
described. Studies carried out in the course of this dissertation consist of five total syntheses of natural products that include bromopyrrole alkaloids nagelamide A, D and agelastatin D as...
Oxygen derived radicals are involved in many aspects of life from aging and cell signaling to disease states as diverse as heart disease, diabetes, neurodegeneration and inflammation. Therefore, understanding the function of antioxidant defense proteins and the effects of oxygen derived radicals on protein function is essential to elucidate the...
An automated multielement flame atomic fluorescence (AF) spectrometer based on microcomputer control was constructed to determine four elements simultaneously. The instrument employs a multiple exit slit monochromator where the light from various exit slits is directed to a single detector with a mirrored funnel. Each element is excited to fluoresce...
In situ reduction of hydrido-tris-(3,5-dimethylpyrazolyl)borato(trioxo) rhenium(V) with triphenylphosphine or triethylphosphite leads to a reactive rhenium(V) species that catalytically deoxygenates epoxides at 75-105°C. The reaction is stereospecific, except for trans- and cis-butene oxide which formed minor amounts of the opposite isomer. A variety of different functional groups were tolerated and even...
In this dissertation, I present the work of developing more efficient and economical techniques for fragmenting large bio-molecules, and ultimately making mass spectrometry a more powerful tool in proteomics, DNA sequencing, and other areas of biomolecular analysis.
Aiming at lowering the installation and operating cost, and delivering electron capture dissociation...
Reported here is an investigation to determine if azinphos-methyl (AZM), an
organophosphate insecticide, adducts to hemoglobin, and if so, whether the
hemoglobin adduct could be used as a quantitative marker of occupational AZM
exposure. We hypothesized that AZM, or a metabolite of AZM, binds to hemoglobin
in erythrocytes forming an...
The fragmentation characteristics of protonated peptides have been investigated using
tandem mass spectrometry (MS/MS) under various fragmentation regimes and detailed
density functional theory (DFT) reaction pathway calculations. The DFT calculations
predict novel salt-bridge stabilized transition structures as well as consecutive reactions
occurring in proton-bound dimers for some of the ions...
Three approaches toward the core of halichlorine and pinnaic acid are described. The first approach entails a racemic transannular nitrone-olefin [3+2] cycloaddition from nitrone 238. Construction of the nitrone 238 began with aldehyde 241. Another key feature in this route involved a ring-closing metathesis for the formation of a 14-membered...
The milk fat globule membrane, a major component in buttermilk, contains many complex lipids known to be involved in a variety of biological processes. Phospholipids, including sphingolipids, exhibit antioxidative, anticarcinogenic, and antiatherogenic properties and have essential roles in numerous cell functions. Filtration coupled with supercritical fluid extraction (SFE) may provide...
The DNA-binding domains of E. coli uracil-DNA glycosylase (Ung) and human replication protein A (hRPA) were studied using a general protocol developed in our laboratory for probing protein-DNA interactions. The procedure involves purification and mass spectrometric analysis of the nucleopeptide-products of a tryptically digested UV-crosslinked protein-nucleic acid complex. In the...
Studies towards the total synthesis of (−)-kendomycin (1), a bacterial metabolite with
a unique molecular architecture and pronounced biological activity, are described. These
studies resulted in the synthesis of advanced intermediate 208, containing all of the
carbon atoms of 1.
A Dötz annulation between alkyne 122 and novel chromium carbenoid...
An interactive man-hybrid computer algorithm is presented
for searching a set of dynamic system parameters which effect a
compromise between performance characteristics and give satisfactory
system sensitivity without any analytical calculations or a
priori indices of performance. The parameter search is conducted
in a real time design situation in which...