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Articles 12721 - 12750 of 13226

Full-Text Articles in Life Sciences

Kinetics Of Two-Substrate Reactions Using Integrated Rate Equations, Leonard D. Holmes May 1988

Kinetics Of Two-Substrate Reactions Using Integrated Rate Equations, Leonard D. Holmes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The usual procedure employed in enzyme kinetic analysis is the method of initial rates. However, it has been appreciated for years that the analysis of enzyme-catalyzed reactions could, in principle, be more efficiently performed by examining the entire time course. There is much more information contained in a progress curve than in a simple initial rate. With the appearance of the computer, the formidable computations necessary for the use of integrated-rate equations are quite possible. The intention of this research was to develop the analytical and statistical methodology for applying an integrated-rate equation to a two-substrate reaction. I have analyzed …


The Bacterial Cell Membrane: Berlin Wall Of The Cell, Hans Kornberg Apr 1988

The Bacterial Cell Membrane: Berlin Wall Of The Cell, Hans Kornberg

DSLS 1987-1988

(This information was taken from the Distinguished Scientist Lecture Series Program 1983-1984).

RECORDING UNAVAILABLE.

Born in Herford, Germany, Dr. Kornberg is Sir William Dunn Professor of Biochemistry, University of Cambridge, and Master of Christ's College, Cambridge. Dr. Kornberg received the B.Sc. and Ph.D. degrees from the University of Sheffield, the M.A. and D.Sc. degrees from the University of Oxford, and the Sc.D. degree from the University of Cambridge. He did postdoctoral research at Yale University, the University of California, Berkeley, and the Public Health Research Institute (New York City) before returning to England to join the Medical Research Council's Cell …


Use Of 52Cr For The Quantitative Determination Of Red Cell Volume, Claude Michael Hanbury Apr 1988

Use Of 52Cr For The Quantitative Determination Of Red Cell Volume, Claude Michael Hanbury

Chemistry & Biochemistry Theses & Dissertations

Chromium-52 has recently been suggested for use as a new agent to label red cells for the in vivo quantitation of red cell volume (1). In this paper, the development and validation of a routine 52cr labeling procedure is described.

The accuracy, precision, and detection limits of chromium analysis by Zeeman effect atomic absorption spectroscopy was evaluated in the concentration range of 1 - 10 ug Cr/L.

Red cell chromium uptake was evaluated as a function of time, temperature, and concentration. Red cells labeled with a 2.5 mg/L chromium solution for 30 minutes at room temperature exhibited optimal label …


Reactions Of Aqueous Chlorine In The Gastric Fluid Of The Rat, Michael Gary Nickelsen Apr 1988

Reactions Of Aqueous Chlorine In The Gastric Fluid Of The Rat, Michael Gary Nickelsen

Chemistry & Biochemistry Theses & Dissertations

Gastric fluid was recovered from Sprague-Dawley rats that had been fasted for 24 hr or 48 hr and administered 4 mL deionized water. The protein, carbohydrate and chloride ion content of the gastric fluid was determined.

When gastric fluid is chlorinated with radiolabeled chlorine to concentrations between 323 and 375 mg/L, analyzed by high performance chromatography followed by liquid scintillation counting, as much as 59% of the radiolabeled chlorine was associated with organic components of the gastric fluid.

Model studies with the aromatic amino acids and the protein pepsin showed the formation of chlorinated analogs. Two chlorinated amino acid derivatives …


Laminin Receptors For Neurite Formation, H. K. Kleinman, Roy C. Ogle, F. B. Cannon, C. D. Little, T. M. Sweeney, L. Luckenbill-Edds Feb 1988

Laminin Receptors For Neurite Formation, H. K. Kleinman, Roy C. Ogle, F. B. Cannon, C. D. Little, T. M. Sweeney, L. Luckenbill-Edds

School of Medical Diagnostics & Translational Sciences Publications

Laminin, a basement membrane glycoprotein promotes both cell attachment and neurite outgrowth. Separate domains on laminin elicit these responses, suggesting that distinct receptors occur on the surface of cells. NG108-15 neuroblastoma-glioma cells rapidly extend long processes in the presence of laminin. We report here that 125I-labeled laminin specifically binds to these cells and to three membrane proteins of 67, 110, and 180 kDa. These proteins were isolated by affinity chromatography on laminin-Sepharose. The 67-kDa protein reacted with antibody to the previously characterized receptor for cell attachment to laminin. Antibodies to the 110-kDa and 180-kDa bands demonstrated that the 110-kDa protein …


Studies Of Transketolase Abnormality In Alzheimer's Disease / Kwan-Fu Rex Sheu, Phd; Donald D. Clarke, Phd; Young-Tai Kim, Phd; John P. Blass, Md, Phd; Bradford J. Harding; Joseph Decicco, Kwan-Fu Rex Sheu, Donald Dudley Clarke Phd, Young-Tai Kim, John P. Blass Jan 1988

Studies Of Transketolase Abnormality In Alzheimer's Disease / Kwan-Fu Rex Sheu, Phd; Donald D. Clarke, Phd; Young-Tai Kim, Phd; John P. Blass, Md, Phd; Bradford J. Harding; Joseph Decicco, Kwan-Fu Rex Sheu, Donald Dudley Clarke Phd, Young-Tai Kim, John P. Blass

Chemistry Faculty Publications

The partially purified transketolase from each of eight well-nourished patients with Alzheimer's disease contained significantly less heat-stable component with a significantly longer half-life of heat inactivation than that from eight controls. Immunochemical studies utilizing antibodies to the purified human liver transketolase did not distinguish between red blood cell transketolases of patients with Alzheimer's disease and those of controls. However, three brains from patients with Alzheimer's disease that were deficient in transketolase activity lacked a 69-kilodalton form on immunoblots. Subtle structural abnormalities of transketolase appear to occur in a high proportion of patients with Alzheimer's disease


Reduced Co2/O2 Specificity Of Ribulose-Bisphosphate Carboxylase/Oxygenase In A Temperature-Sensitive Chloroplast Mutant Of Chlamydomonas, Zhixiang Chen, Chris J. Chastain, Souhail R. Al-Abed, Raymond Chollet, Robert J. Spreitzer Jan 1988

Reduced Co2/O2 Specificity Of Ribulose-Bisphosphate Carboxylase/Oxygenase In A Temperature-Sensitive Chloroplast Mutant Of Chlamydomonas, Zhixiang Chen, Chris J. Chastain, Souhail R. Al-Abed, Raymond Chollet, Robert J. Spreitzer

Department of Biochemistry: Faculty Publications

The Chlamydomonas reinhardtii chloroplast mutant 68-4PP is phenotypically indistinguishable from wild type at 25°C but fails to grow photosynthetically at 35°C. It had about 30% of the wild-type level of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) holoenzyme and carboxylase activity when grown at 25°C, but less than 15% when grown at 35°C. Pulse-labeling with 35S showed that the decrease in enzyme level at the restrictive temperature was not a result of reduced synthesis of enzyme subunits. The CO2/O2 specificity factor (VcKo/VoKc, where Vc and Vo are Vmax …


The Purification Of Ribosomal Rna Gene Chromatin From Physarum Polycephalum, Sally A. Amero, Roy C. Ogle, John L. Keating, Vicky L. Montoya, Wendy L. Murdoch, Robert M. Grainger Jan 1988

The Purification Of Ribosomal Rna Gene Chromatin From Physarum Polycephalum, Sally A. Amero, Roy C. Ogle, John L. Keating, Vicky L. Montoya, Wendy L. Murdoch, Robert M. Grainger

School of Medical Diagnostics & Translational Sciences Publications

We have undertaken the purification of ribosomal RNA gene (rDNA) chromatin from the slime mold Physarum polycephalum, in order to study its chromatin structure. In this organism rDNA exists in nucleoli as highly repeated minichromosomes, and one can obtain crude chromatin fractions highly enriched in rDNA from isolated nucleoli. We first developed a nucleolar isolation method utilizing polyamines as stabilization agents that results in a chromatin fraction containing far more protein than is obtained by the more commonly used divalent cation isolation methods. The latter method appears to result in extensive histone loss during chromatin isolations. Two methods were then …


Limnological Monitoring Data For Lake Mead During 1987: Technical Report No. 20, Larry J. Paulson Jan 1988

Limnological Monitoring Data For Lake Mead During 1987: Technical Report No. 20, Larry J. Paulson

Publications (WR)

Limnological monitoring was conducted in Las Vegas Bay and Boulder Basin from April to December of 1987. The purpose of the monitoring was to (i) document possible changes in water quality resulting from decreased phosphorus loading in Las Vegas Wash, and (ii) establish a data base for evaluating the adequacy of water quality standards.


Changes In The Morphometry Of Las Vegas Wash And The Impact On Water Quality, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation Jan 1988

Changes In The Morphometry Of Las Vegas Wash And The Impact On Water Quality, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation

Publications (WR)

Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mead. Over 80 percent of the normal discharge of approximately 3.4 m3/s (120 ft3/s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly …


Improved Selective Medium For The Isolation Of Treponema Hyodysenteriae, Robert A. Kunkle, J. M. Kinyon Jan 1988

Improved Selective Medium For The Isolation Of Treponema Hyodysenteriae, Robert A. Kunkle, J. M. Kinyon

School of Veterinary and Biomedical Sciences: Faculty Publications

An agar medium with improved selection for Treponema hyodysenteriae was developed. Cultures of T. hyodysenteriae and T. innocens, feces from 11 clinically normal pigs, and colonic contents from 6 pigs with gross lesions consistent with swine dysentery were diluted in phosphate-buffered saline and plated on Trypticase soy agar (BBL Microbiology Systems, Cockeysville, Md.) with 5% citrated bovine blood (TSA), TSA with 400 ,ug of spectinomycin per ml (TSA-S400), TSA-S400 with 25 ,ug each of colistin and vancomycin per ml, and TSA with 5% pig feces extract and five antimicrobial agents (spiramycin, rifampin, vancomycin, colistin, and spectinomycin) (BJ). Viable numbers …


Comparison Of Cyclic Nucloetide Phosphodiesterase In Physarum Favicomum, C. Kay Holtman, Tammy K. Ebsen, Judith A. Bean, J. Scott Bryles, Thomas J. Lynch Jan 1988

Comparison Of Cyclic Nucloetide Phosphodiesterase In Physarum Favicomum, C. Kay Holtman, Tammy K. Ebsen, Judith A. Bean, J. Scott Bryles, Thomas J. Lynch

Journal of the Arkansas Academy of Science

We have studied both cyclic AMP phosphodiesterase and cyclic GMP phosphodiesterase in the myxomycete Physarum flavicomum. The cyclic AMP phosphodiesterase preparations were isolated from both the diploid plasmodial stage of the lifecycle and the haploid myxamoebal stage. The plasmodial enzyme was prepared from spent medium (extracellular) and also from purified nuclei. The myxamoebal enzyme was prepared from purified nuclei. Cyclic GMP phosphodiesterase activity was studied in purified nuclei isolated from the plasmodium. One unusual feature of all the enzymes from the plasmodium is extreme heat stability; they remain catalytically active even after exposure to a boiling water bath for twenty …


Nucleotide Sequence Of The Fadr Gene, A Multifunctional Regulator Of Fatty Acid Metabolism In Escherichia Coli, Concetta C. Dirusso Jan 1988

Nucleotide Sequence Of The Fadr Gene, A Multifunctional Regulator Of Fatty Acid Metabolism In Escherichia Coli, Concetta C. Dirusso

Department of Biochemistry: Faculty Publications

The Escherichia coli fadR gene is a multifunctional regulator of fatty acid

and acetate metabolism. In the present work the nucleotide sequence of the

1.3 kb DNA fragment which encodes FadR has been determined. The coding

sequence of the fadR gene is 714 nucleotides long and is preceded by a typical

E. coli ribosome binding site and is followed by a sequence predicted to be

sufficient for factor-independent chain termination. Primer extension experiments

demonstrated that the transcription of the fadR gene initiates with an

adenine nucleotide 33 nucleotides upstream from the predicted start of

translation. The derived fadR peptide has …


Incorporation Of A Product Of Mevalonic Acid Metabolism Into Proteins Of Chinese Hamster Ovary Nuclei, Michael Sinensky, L. A. Beck, T. Hosick Jan 1988

Incorporation Of A Product Of Mevalonic Acid Metabolism Into Proteins Of Chinese Hamster Ovary Nuclei, Michael Sinensky, L. A. Beck, T. Hosick

Faculty Publications, Biological Sciences

We have examined the nuclear localization of isoprenylated proteins in CHO-K1 cells labeled with [14C]mevalonate. Nuclear proteins of 68, 70, and 74 kD, posttranslationally modified by an isoprenoid, are also components of a nuclear matrix-intermediate filament preparation from CHO cells. Furthermore, the 68-, 70-, and 74-kD isoprenylated polypeptides are immunoprecipitated from cell extracts with two different anti-lamin antisera. Based on exact two-dimensional comigration with lamin B, both from rat liver lamin and CHO nuclear matrix-intermediate filament preparations, and its immunoprecipitation with anti-lamin antisera, we conclude that the 68-kD isoprenylated protein found in nuclei from [14C]mevalonate-labeled CHO cells is lamin B. …


Influence Of Synaptic Membrane Cholesterol Content On Dopaminergic Function, Patricia A. Maguire Jan 1988

Influence Of Synaptic Membrane Cholesterol Content On Dopaminergic Function, Patricia A. Maguire

Dissertations

No abstract provided.


Time Delayed Protein Complementation, Diana L. Lakusta Dec 1987

Time Delayed Protein Complementation, Diana L. Lakusta

Loma Linda University Electronic Theses, Dissertations & Projects

The time delayed complementation of plant proteins was tested in weanling Sprague-Dawley male rats by measuring growth rates as well as plasma and tissue free amino acids. Diets of pinto beans with rice, corn or wheat were pair-fed in combination or alternating 4 times a day at 6 and 11 am, and 4 and 9 pm for 4 weeks. Plasma, liver and muscle samples were obtained 2 hours postprandial, a time determined most suitable for sacrifice, and analyzed for free amino acids via ion-exchange chromatography. There were no significant differences in growth of rats fed combination or alternating diets.during week …


The Refined Crystal Structure Of A Fully Active Semisynthetic Ribonuclease At 1.8 Å Resolution, Philip D. Martin, Marilynn S. Doscher, Brian Fp Edwards Nov 1987

The Refined Crystal Structure Of A Fully Active Semisynthetic Ribonuclease At 1.8 Å Resolution, Philip D. Martin, Marilynn S. Doscher, Brian Fp Edwards

Biochemistry and Molecular Biology Faculty Publications

A fully active, semisynthetic analog of bovine ribonuclease A, comprised of residues 1-118 of the molecule in a noncovalent complex with the synthetic peptide analog of residues 111-124, has been crystallized in space group P3(2)21 from a solution of 1.3 M ammonium sulfate and 3.0 M cesium chloride at pH 5.2. The crystallographic structure was determined by rotation and translation searches utilizing the coordinates for ribonuclease A reported by Wlodawer and Sjolin (Wlodawer, A., and Sjolin, L. (1983) Biochemistry 22, 2720-2728) and has been refined at 1.8-A resolution to an agreement factor of 0.204. Most of the structure of the …


Synthesis And Characterization Of N-Alkyl-Adenosine-5'-Diphosphates, Han-Ping Huang Oct 1987

Synthesis And Characterization Of N-Alkyl-Adenosine-5'-Diphosphates, Han-Ping Huang

Chemistry & Biochemistry Theses & Dissertations

n-Alkylphosphates and adenosine derivatives have been observed to be competitive inhibitors of coenzyme molecules in many NAD+ requiring enzymes. In earlier studies, adenosine derivatives such as AMP, ADP and ADP-ribose were found to be coenzyme competitive inhibitors of the Lactate Dehydrogenase catalyzed reaction. However, n-alkylphosphates, to the contrary, + were found to be noncompetitive inhibitors of NAD+.

Furthermore, it was observed previously in Dr. Yuan's laboratory that the effect of n-octylphosphate on the LDH catalyzed reaction was changed from noncompetitive to competitive in the presence of low concentration of AMP. Rossmann et al. reported that the binding …


Investigation Of Complex Formation By Oligomers Of Cytosine And Guanosine, Steven Roberts Davis Oct 1987

Investigation Of Complex Formation By Oligomers Of Cytosine And Guanosine, Steven Roberts Davis

Chemistry & Biochemistry Theses & Dissertations

Duplex formation between oligo(C:G) n where n=3 to 4 was shown not to occur under conditions favorable for duplex formation between poly G and poly C. Instead, a stable guano sine self-structure was found to form which a Tm of 50°C for (Gp)3 and 80°C for (Gp)4 at strand concentrations of 10-5M in 1M NaCl. Neither a duplex nor a self-structure formed in the absence of salt.

Oligomers of guanosine and cytosine were obtained by basic hydrolysis and separated according to chain length using DEAE Sephadex column chromatography. Separation of cytosine oligomers with chain lengths …


Signal Processing In Bacterial Chemotaxis, Jimmie Marquette Smith Sep 1987

Signal Processing In Bacterial Chemotaxis, Jimmie Marquette Smith

Loma Linda University Electronic Theses, Dissertations & Projects

This study localized 1) the site of ATP utilization in the signal transduction pathway of bacterial chemotaxis and 2) the point of convergence of the methylation-independent systems of chemotaxis with the methylation-dependent system. The site of ATP utilization was localized at the CheY protein/switch point. In an Eaeheriehia call strain (BT3077) containing the cheY, motor and switch genes, ATP depletion, accomplished by treating the cells with arsenate, suppressed the CheY protein-induced tumbling. ATP was not required by the switch for directing the clockwise and counterclockwise rotations of the flagellar motor. ATP did not appear to be required for normal steady-state …


Intracellular Protein Degradation In A Mesophile And A Thermophile Of The Genus Bacillus, Cameron C. Hoover Aug 1987

Intracellular Protein Degradation In A Mesophile And A Thermophile Of The Genus Bacillus, Cameron C. Hoover

Masters Theses

14C-leucine was incorporated into th e proteins of the mesophile Bacillus licheniformis and the thermophile Bacillus stearothermophilus. Aliquots of the cell suspension were treated with chloramine-T in order to decarboxylate the 14C-leucine that was released as the proteins degraded. The 14CO2 was trapped and counted. This allowed for the determination of the extent of intracellular protein degradation at various tem peratures and at various stages of the growth cun/e. For the mesophile, the extent of degradation increased with temperature from 30° C to 55° C. For the thermophile, no significant amount of degradation occurred until …


Lake Mead Cover Enhancement Project, Jennifer Stevens Haley, Suzanne Leavitt, Larry Paulson, Donald H. Baepler Jul 1987

Lake Mead Cover Enhancement Project, Jennifer Stevens Haley, Suzanne Leavitt, Larry Paulson, Donald H. Baepler

Publications (WR)

Ninety-three wildlife agencies were surveyed for information on their attempts to improve fish habitat. In addition, an annotated bibliography including over 100 summaries was completed on: 1. largemouth bass cover requirements and preferences, 2. use and effectiveness of artificial cover, 3. aquatic plant introduction and species requirements for germination and establishment, 4. terrestrial plant introduction and species requirements for germination and establishment, and 5. nutrient exchange between sediment, aquatic plants, and water. A reconnaissance of existing terrestrial and aquatic vegetation was completed in June 1986 including the production of a video tape of the Nevada shoreline of Lake Mead. Cover …


Synthesis Of Potential Long Acting Calcium Channel Antagonists: A Study Of 1,4-Dihydropyridine Analogs, Thomas E. Christos Jul 1987

Synthesis Of Potential Long Acting Calcium Channel Antagonists: A Study Of 1,4-Dihydropyridine Analogs, Thomas E. Christos

Chemistry & Biochemistry Theses & Dissertations

An investigation was undertaken to synthesize and evaluate longer acting analogs to the antihypertensive agent nifedipine. Analogs that are capable of covalent bonding to the nifedipine receptor were considered. These compounds may show increased activity as they will remain at the receptor for a longer period of time.

During the course of this study, previously unreported and unexpected products were encountered and lead to a more intense examination of the Hantzsch synthesis. Of particular interest was the oxazolidine 25 which was a major component of the Hantzsch synthesis when ethanolamine was used instead of ammonium hydroxide. Also isolated during this …


Las Vegas Wash And Lake Mead Proposed Water Quality Standards: Revisions And Rationale, State Of Nevada: Division Of Environmental Protection May 1987

Las Vegas Wash And Lake Mead Proposed Water Quality Standards: Revisions And Rationale, State Of Nevada: Division Of Environmental Protection

Publications (WR)

Rationale of review and for proposed changes to the Nevada Pollution Control Regulations (NAC 445.1354, 445.1355, 445.1356, 455.1367, 445.1352, 445.1353, 445.1350, 445.1351) before the State Environmental Commission on June 23 and 24, 1987.


Raw Nutrient Data, Leanna Gail May 1987

Raw Nutrient Data, Leanna Gail

Publications (WR)

Data collected at various stations around Lake Mead. Includes information about substances present in various water samples.


Mechanism Of Iron Transport In Mycelia Sterilia Ep-76, Jonathan P. Adjimani May 1987

Mechanism Of Iron Transport In Mycelia Sterilia Ep-76, Jonathan P. Adjimani

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The cyclic trihydroxamic acid, N, N', N' '-triacetylfusarinine C, produced by Mycelia sterilia EP-76, is shown to be a ferric ionophore for this organism. The association constant for ferric-N, N', N' '-triacetylfusarinine C complex was determined to be log K=32.5. Other iron chelating agents, such as rhodotorulic acid, citric acid, or the monomeric subunit of triacetylfusarinine C, N-acetyl- fusarinine, delivered iron to the cells by an indirect mechanism involving iron exchange into triacetylfusarinine C. In vitro ferric ion exchange was found to be rapid with triacetylfusarinine C. Gallium uptake rates comparable to those of iron were observed with the chelating …


Purification And Characterization Of An Inhibitor Of Thymidine Uptake From Culture Supernatants Of Human Tonsil Lymphocytes, Abdolreza Zarnegar May 1987

Purification And Characterization Of An Inhibitor Of Thymidine Uptake From Culture Supernatants Of Human Tonsil Lymphocytes, Abdolreza Zarnegar

Electronic Theses and Dissertations

Lymphocytes from human tonsils were cultured in the absence of serum for 3 days. In the presence of the concentrated culture supernatant the proliferative response of PBL, to con A, as measured by the uptake of ('3)H-tdr, was significantly reduced. The suppressor substance was referred to as SMAL (suppressor of mitogen activated lymphocytes). The estimated molecular weight of SMAL under nondenaturing conditions was 100,000-300,000. SMAL also suppressed the incorporation of ('3)H-tdr by a variety of mouse and human tumor cell lines. The activity of SMAL was sensitive to pronase and heating at 100(DEGREES)C for 30 minutes but insensitive to RNase. …


An Improved Method For Transferring Nucleic Acids To Nylon Membranes, Bruce D. Parker May 1987

An Improved Method For Transferring Nucleic Acids To Nylon Membranes, Bruce D. Parker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Methods currently in use for the separation and identification of specific segments of nucleic acids involve long transfer periods or elaborate apparatuses and result in the production of a single blot. Contamination by organisms or enzymes is always a factor to be dealt with. An improved method for transferring nucleic acids from acrylamide or agarose gels for use in hybridization has been developed. This method uses NaOH as the blotting medium to improve the rate and efficiency of transfer to nylon membranes. As many as six blots can be obtained within one hour using this method. This method is effective …


Production Of Thymine Dimer In Dna From Mesophilic And Thermophilic Bacteria By Uv Irradiation, F Redrick Shu-Chung Yein Apr 1987

Production Of Thymine Dimer In Dna From Mesophilic And Thermophilic Bacteria By Uv Irradiation, F Redrick Shu-Chung Yein

Dissertations

The in vitro production of thymine dimer (TT) in DNA, isolated from the mesophile (B. licheniformis) and the thermophile (B. stearothermophilus), was carried out by UV irradiation (254 nm) at three different temperatures (35, 45, and 55(DEGREES)C). The production of TT from the thermophilic DNA was significantly higher than that from the mesophilic DNA. This was the case at all three irradiation temperatures. The increase in TT production per 10(DEGREES)C increase in irradiation temperature was four times higher for the thermophile than that for the mesophile. It was concluded that the DNA from the thermophile was photochemically less stable than …


Pyrimidines. 8. Chlorination Of 6-Methyluracil With Phosphorus Oxychloride In The Presence Of Trialkyamines / Herman Gershon [Ab], Anthony T. Grefig [A], And Donald D. Clarke [B] [A] Boyce Thompson Institute For Plant Research At Cornell University, Ithaca, New York 14853 [B] Department Of Chemistry, Fordham University, Bronx, New York 10458, Herman Gershon, Anthony T. Grefig, Donald Dudley Clarke Phd Jan 1987

Pyrimidines. 8. Chlorination Of 6-Methyluracil With Phosphorus Oxychloride In The Presence Of Trialkyamines / Herman Gershon [Ab], Anthony T. Grefig [A], And Donald D. Clarke [B] [A] Boyce Thompson Institute For Plant Research At Cornell University, Ithaca, New York 14853 [B] Department Of Chemistry, Fordham University, Bronx, New York 10458, Herman Gershon, Anthony T. Grefig, Donald Dudley Clarke Phd

Chemistry Faculty Publications

The effect of the tertiary amines triethyl, tri-n-propyl, and tri-n-butylamines on the chlorination of 6-methyluracil by phosphorus oxychloride was studied. A comparison with the reaction of preformed 2,4-dichloro-6-methylpyrimidine and triethylamine in toluene was made. The reaction in phosphorus oxychloride in the presence of triethylamine afforded low yields of 2-diethylamino derivative after short heating periods and high yields of the 2,4-bis(diethylamino) derivative after 188 hours of boiling. Heating the preformed 2,4-dichloro-6-methylpyrimidine in toluene in the presence of triethylamine yielded primarily the 2-diethylaminopyrimidine along with a small amount of the 4-diethylamino isomer. After 188 hours, the product mixture was composed of 87% …