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Articles 13231 - 13260 of 13694

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois Dec 1986

Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Macroscopically, the testes of Chthonerpeton indistinctum consist of a series of oval lobes. The number and size of lobes is variable in Chthonerpeton indistinctum. Histologically, the testes are divided into structural units, locules separated by septa of connective tissue. Inside of each locule spermatogenesis takes place in cysts of germinal cells that divide synchronically. Chthonerpeton indistinctum is divided chronologically into four stages of development based on the shape of the nuclei of the spermatids and their arrangement in the cyst: (1) round, (2) kidney shaped, (3) attenuate, and (4) bouquet arrangement.


The Synthesis And Evaluation Of The Cardiovascular Activity Of Novel Imidazole Ring Systems, Joseph E. De Los Angeles Oct 1986

The Synthesis And Evaluation Of The Cardiovascular Activity Of Novel Imidazole Ring Systems, Joseph E. De Los Angeles

Chemistry & Biochemistry Theses & Dissertations

An investigation was undertaken to synthesize and evaluate the cardiovascular activity of two imidazole ring systems. Imidazoles with hypotensive activity would provide novel potential antihypertensive drugs. These novel structures may also find use as chemical probes in the study of the cardiovascular system and as prototypes for other potential cardiovascular agents.

The histamine derivative, 7,7-dipyridyl-4,5,6,7-tetrahydroimidazo-[4,5-c]pyridine (ligand l), was demonstrated to possess significant hypotensive activity in laboratory rats. A 15 mg/Kg dose of ligand 1 produces a statistically significant decrease in blood pressure when injected IP. This hypotensive effect is also associated with marked increase in heart rate. Although compound 1 …


Determination Of Human Sperm Cell Acrosin Activity From Normal And Subfertile Men, Dilrowshan H. Haque Jul 1986

Determination Of Human Sperm Cell Acrosin Activity From Normal And Subfertile Men, Dilrowshan H. Haque

Chemistry & Biochemistry Theses & Dissertations

Acrosin is an acrosomal enzyme which is reported to be involved in sperm penetration through cumulus, zona, and ooplasma. This enzyme has been reported to be significantly lower in sperm of infertile men compared to sperm of fertile men. The acrosin assay which has been developed can be used for studies in patients with suspected infertility and may be used on a fraction of most semen specimens being evaluated in a clinical andrology laboratory.

Within-run precision studies yielded coefficients of variation of 11% for a low-activity pool and 9% for normalactivity pool specimens. Between-run precision studies using a single donor …


Cooperativity Of Ligand Binding As A Function Of Monomer-Dimer Equilibrium Parameters And Acceptor Concentration, George K. Wolfer Jun 1986

Cooperativity Of Ligand Binding As A Function Of Monomer-Dimer Equilibrium Parameters And Acceptor Concentration, George K. Wolfer

Loma Linda University Electronic Theses, Dissertations & Projects

A general monomer-dimer equilibrium system involving ligand interactions is presented. Cooperativity features of specific limited models are analyzed by selecting the appropriate family of equilibrium constants from this general scheme. Each system is then characterized in terms of Hill coefficient dependency on alterations in values of equilibrium constants and total acceptor concentration. This method permits comparison of predicted cooperativity trends between systems. Contrasting reports concerning cooperativity dependencies for certain defined equilibrium systems are compared and the discrepancies resolved. Characteristics of cooperativity binding patterns are shown to include symmetry about dimerization association constant values, both positive and negative cooperativity for a …


An Immunochemical Analysis Of Alcoholic Hyaline And Its Relationship To Keratin Intermediate Filaments, David L. Drexler Jun 1986

An Immunochemical Analysis Of Alcoholic Hyaline And Its Relationship To Keratin Intermediate Filaments, David L. Drexler

Loma Linda University Electronic Theses, Dissertations & Projects

Alcoholic Hyaline (AH) and keratin intermediate filaments possess ultrastructural, biochemical and immunochemical similarities. This study compares human AH, human stratum corneum keratin (HSCK) and normal human liver cytokeratin (HCK) by quantitative immunochemical means, using polyclonal as well as monoclonal antibodies. Enzyme-linked immunosorbent assays (ELISAs) were employed, as well as "immunoblotting" and immunocytochemical techniques. HCK was isolated using Triton X-100 and "high-salt” buffers and exhibited seven major polypeptide bands on SDS-PAGE (41-58 kd). Antisera were made toward HCK and the two major HCK bands. Other immunochemicals included antisera toward AH, the three major AH bands, and HSCK, as well as 3 …


Interaction Of Putative Estrogens And The Estrogen Receptor System In Leydig Cells In The Balb/C Mouse Testis Resulting In The Initiation Of Dna Synthesis, R. Lloyd Juriansz Jun 1986

Interaction Of Putative Estrogens And The Estrogen Receptor System In Leydig Cells In The Balb/C Mouse Testis Resulting In The Initiation Of Dna Synthesis, R. Lloyd Juriansz

Loma Linda University Electronic Theses, Dissertations & Projects

Continuous administration of estrogens for 7-9 months, both steroidal and nonsteroidal, to male BALB/c mice, leads to the formation of testicular Leydig cell tumors. Three days following the subcutaneous implantation of a pellet of estrogen in cholesterol, there is a peak in the incorporation of 3H-tymidine into the DNA of the interstitial cells. These effects are hypothesized to be mediated by the estrogen receptor system in the Leydig cell. Common experimental techniques for the measurement of hormone binding, such as dextran coated charcoal treatment, proved to be impossible to employ in this system, therefore a procedure was developed using …


Mössbauer Spectroscopic Studies Of Hemoglobin And Its Isolated Subunits, G. R. Hoy, D. C. Cook, R. L. Berger, F. K. Friedman May 1986

Mössbauer Spectroscopic Studies Of Hemoglobin And Its Isolated Subunits, G. R. Hoy, D. C. Cook, R. L. Berger, F. K. Friedman

Physics Faculty Publications

Samples of 90% enriched 57Fe hemoglobin and its isolated subunits have been prepared. Mössbauer spectroscopic measurements have been made on three such samples. Sample one contained contributions of oxyhemoglobin, deoxyhemoglobin, and carbonmonoxyhemoglobin. This sample was studied from a temperature of 90 K down to 230 mK. Measurements were also made at 4.2 K using a small applied magnetic field of 1.0 T. In general, the measured quadrupole splittings and isomer shifts for each component agreed with previous measurements on single component samples in the literature, and thus demonstrated that chemically enriched hemoglobin has not been altered. The second and …


The Effects Of Luteinizing Hormone And Adenosine 3',5'-Cyclic Monophosphate On Phospholipid Metabolism By Luteal Mitochondria, Jim John Sadighian Apr 1986

The Effects Of Luteinizing Hormone And Adenosine 3',5'-Cyclic Monophosphate On Phospholipid Metabolism By Luteal Mitochondria, Jim John Sadighian

Chemistry & Biochemistry Theses & Dissertations

Luteinizing hormone (LH) increases intracellular concentrations of adenosine 3', 5 '-cyclic monophosphate and the phosphoinositides, phosphatidylinositol (PI), PI 4'-phosphate (PIP) and PI 4' .5 1 - bispbosphate (PIP2). It is believed that cAMP and the phosphoinositides act concertedly to regulate mitochondrial conversion of cholesterol to pregnenolone. This study examined the effects of LH and N6 ,O2 -dibutyryl cAMP (dbcAMP) on phospholipids metabolism by luteal mitochondria and the influence of dbcAMP and the phosphoinosi tides on mitochondrial steroid production. Mitochondria were isolated from unincubated and incubated luteal tissue by differential centrifugation. Phospholipids were extracted from the mitochondria …


Magnesium, Copper And Zinc Concentrations In Blood From Children With Diabetes Mellitus, Linda Lowers Jenkins Apr 1986

Magnesium, Copper And Zinc Concentrations In Blood From Children With Diabetes Mellitus, Linda Lowers Jenkins

Chemistry & Biochemistry Theses & Dissertations

Trace element levels in blood from diabetic children were investigated and compared to control children. Plasma, erythrocyte, mononuclear and polymorphonuclear cells were analyzed for magnesium, copper, and zinc content. Leukocyte separation was performed by density gradient centrifugation on Ficoll-Hypaque, followed by washing steps to remove platelet contamination and hypotonic lysis to remove red cell contamination. Polarized Zeeman-effect atomic absorption spectroscopy was used for trace metal analysis.

Decreased plasma magnesium levels were observed in the diabetic children. This finding is well documented and probably due to increased urinary magnesium loss from glycosuria. Lymphocyte magnesium levels in the diabetic children were also …


Yeast Mannans: Use As A Transport Vehicle For Peptides, Jacqueline Cesario Lee Apr 1986

Yeast Mannans: Use As A Transport Vehicle For Peptides, Jacqueline Cesario Lee

Masters Theses

Yeast mannans are phosphorylated glycopeptides found in various species of yeast. Their similarity to the mannose-phosphate signal for intracellular lysosomal uptake led mannans to be considered as a possible vehicle for increasing cellular affinity for peptides. Insulin was used as a model peptide and was conjugated to mannans by two coupling methods. The conjugated mannan-insulins were compared to insulin on the basis of cellular binding and ability to induce typical insulin biological effects.


Purification And Characterization Of A Soluble And A Particulate Glutamate Dehydrogenase From Rat Brain / Arlene D. Colon, Andreas Plaitakis, Antonis Perakis, Soll Berl, And Donald D. Clarke Department Of Neurology, Mount Sinai School Of Medicine, New York, And Department Of Chemistry, Fordham University, Bronx, New York, U.S.A., Arlene D. Colon, Andreas Plaitakis, Antonis Perakis, Donald Dudley Clarke Phd Jan 1986

Purification And Characterization Of A Soluble And A Particulate Glutamate Dehydrogenase From Rat Brain / Arlene D. Colon, Andreas Plaitakis, Antonis Perakis, Soll Berl, And Donald D. Clarke Department Of Neurology, Mount Sinai School Of Medicine, New York, And Department Of Chemistry, Fordham University, Bronx, New York, U.S.A., Arlene D. Colon, Andreas Plaitakis, Antonis Perakis, Donald Dudley Clarke Phd

Chemistry Faculty Publications

Glutamate dehydrogenase (GDH) activity was determined in high-speed fractions (1 00,000 g for 60 min) obtained from whole rat brain homogenates after removal of a low-speed pellet (480 g for 10 min). Approximately 60% of the high-speed GDH activity was particulate (associated with membrane) and the remaining was soluble (probably of mitochondrial matrix origin). Most of the particulate GDH activity resisted extraction by several commonly used detergents, high concentration of salt, and sonication; however, it was largely extractable with the cationic detergent cetyltrimethylammonium bromide (CTAB) in hypotonic buffer solution. The two GDH activities were purified using a combination of hydrophobic …


The Subcellular Localization Of Glutamate Dehydrogenase (Gdh): Is Gdh A Marker For Mitochondria In Brain? / James C. K. Lai, Kwan-Fu Rex Sheu, Young Tai Kim, Donald D. Clarke, And John P. Blass Department Of Neurology, Cornell University Medical College And Altschul Laboratory For Dementia Research Burke Rehabilitation Center White Plains, Ny 10605 And Department Of Medicine Cornell University Medical College New York, Ny 10021, James C. K. Lai, Kwan-Fu Rex Sheu, Young Tai Kim, Donald Dudley Clarke Phd Jan 1986

The Subcellular Localization Of Glutamate Dehydrogenase (Gdh): Is Gdh A Marker For Mitochondria In Brain? / James C. K. Lai, Kwan-Fu Rex Sheu, Young Tai Kim, Donald D. Clarke, And John P. Blass Department Of Neurology, Cornell University Medical College And Altschul Laboratory For Dementia Research Burke Rehabilitation Center White Plains, Ny 10605 And Department Of Medicine Cornell University Medical College New York, Ny 10021, James C. K. Lai, Kwan-Fu Rex Sheu, Young Tai Kim, Donald Dudley Clarke Phd

Chemistry Faculty Publications

Glutamate dehydrogenase (GDH, EC 1.4.1.2) has long been used as a marker for mitochondria in brain and other tissues, despite reports indicating that GDH is also present in nuclei of liver and dorsal root ganglia. To examine whether GDH can be used as a marker to differentiate between mitochondria and nuclei in the brain, we have measured GDH by enzymatic activity and on immunoblots in rat brain mitochondria and nuclei which were highly enriched by density-gradient centrifugation methods. The activity of GDH was enriched in the nuclear fraction as well as in the mitochondrial fraction, while the activities of other …


Concanavalin A-Nonbinding Enzymes Of Crotalus Scutulatus Scutulatus Venom, C. K. Childs, Michael W. Hinson, Dewey H. Sifford, Bob D. Johnson Jan 1986

Concanavalin A-Nonbinding Enzymes Of Crotalus Scutulatus Scutulatus Venom, C. K. Childs, Michael W. Hinson, Dewey H. Sifford, Bob D. Johnson

Journal of the Arkansas Academy of Science

Crotalus scutulatus scutulatus crude venom was separated into two fractions by Concanavalin A Sepharose 4B affinity chromatography. The Concanavalin A-nonbinding fraction (F-l) exhibited phosphomonoesterase (orthophosphoric monoester phosphohydrolase EC 3.1 .3.2), phosphodiesterase, 5 '-nucleotidase (5 '-ribonucleotide phosphohydrolase EC 3.1.3.5), phospholipase A (phosphatidate 2-acylhydrolase EC 3.1.1.4), hyaluronidase (hyaluronate glycanohydrolase EC 3.2.1.d), N-benzoyl-Larginine ethyl esterase, p-toluenesulfonyl-L-arginine methyl esterase, L-amino acid oxidase (L-amino acid: O2 oxidoreductase [deaminating] EC 1.4.3.2), and caseinolytic activities. Thrombin-like and NAD nucleosidase (5 '-ribonudeotide phosphohydrolase EC 3.1.3.5) activities were not observed. DEAE Sephadex A-50 ion exchange chromatography by two stage elution of F-l yielded several fractions having proteinase activities. Proteinase …


Annual Ryegrass Toxicity Research Update, A G P Brown, P. Vogal Jan 1986

Annual Ryegrass Toxicity Research Update, A G P Brown, P. Vogal

Journal of the Department of Agriculture, Western Australia, Series 4

Annual ryegrass toxicity (ARGT) is a complex disease that kills sheep and cattle grazing pastures which contain infected ryegrass. The disease results when a nematode (Anguina agrostis) and a batcerium (Corynebacterium sp.) invade annual ryegrass and cause the seed heads to become toxic as the grass dries off.

The bacterium produces a complex toxin of 18 glycolipid compounds or corynetoxins which have been found to be virtually identical to the antibiotic tunicamycin.


In Vitro Phosphorylation Of Maize Leaf Phosphoenolpyruvate Carboxylase, Raymond J. A. Budde, Raymond Chollet Jan 1986

In Vitro Phosphorylation Of Maize Leaf Phosphoenolpyruvate Carboxylase, Raymond J. A. Budde, Raymond Chollet

Department of Biochemistry: Faculty Publications

Autoradiography of total soluble maize (Zea mays) leaf proteins incubated with 32P-labeled adenylates and separated by denaturing electrophoresis revealed that many polypeptides were phosphorylated in vitro by endogenous protein kinase(s). The most intense band was at 94 to 100 kilodaltons and was observed when using either [γ -32P]ATP or [β-32P]ADP as the phosphate donor. This band was comprised of the subunits of both pyruvate, Pi dikinase (PPDK) and phosphoenolpyruvate carboxylase (PEPCase). PPDK activity was previously shown to be dark/light-regulated via a novel ADP-dependent phosphorylation/Pi-dependent dephosphorylation of a threonyl residue. The identity of the acidstable 94 …


Solid Phase Extraction Of Mammalian Cell Mitochondrial Dna And Its Electrophoretic Separation In Agarose Gels, Theresa Brick-Miller Jan 1986

Solid Phase Extraction Of Mammalian Cell Mitochondrial Dna And Its Electrophoretic Separation In Agarose Gels, Theresa Brick-Miller

Biological Sciences Theses & Dissertations

An improved and efficient electrophoretic procedure for the isolation of mitochondrial DNA (mtDNA) is described. The solid phase extraction procedure for the isolation of mtDNA involves embedding as few as 200,000 Ehrlich ascites tumor cells into a block of agarose, digestion of cellular membranes by detergent action and subsequent electrophoretic separation of nucleic acids in agarose gels. Genomic DNA remains in the original block of agarose while the mtDNA migrates in the separation gel to a position equivalent to that obtained for mtDNA isolated by traditional procedures.

The efficacy of a large number of detergents, agarose concentrations, embedding conditions, embedding …


The Effects Of Various Adenosine And Xanthine Analogues On Mammalian Sperm Motility, Daniel Joseph Cushing Jan 1986

The Effects Of Various Adenosine And Xanthine Analogues On Mammalian Sperm Motility, Daniel Joseph Cushing

Masters Theses

Caffeine, theophylline, and a number of other xanthine analogues have been shown to stimulate the motility of mammalian spermatozoa. The mechanism by which these compounds act was assumed to be cAMP phosphodiesterase inhibition. However, it has recently been shown that many of the responses elicited by alkylxanthines and their analogues in various tissues are not the result of cAMP phosphodiesterase inhibition but by antagonism of endogenous adenosine. Using the recently described transmembrane migration method this study observed the effect of a number of xanthine and adenosine analogues on mammalian sperm motility. The hypothesis to be tested was that the increase …


Isolation Of Nuclei From Physarum Flavicomum: Demonstration Of Nuclear Cyclic Acid Amp Phosphodiesterase, Judith A. Bean, Maurice G. Kleve, Thomas J. Lynch Jan 1986

Isolation Of Nuclei From Physarum Flavicomum: Demonstration Of Nuclear Cyclic Acid Amp Phosphodiesterase, Judith A. Bean, Maurice G. Kleve, Thomas J. Lynch

Journal of the Arkansas Academy of Science

Cyclic AMP phosphodiesterase activity in the nucleus of the myxomycete Physarum flavicomum was demonstrated by cytochemical staining utilizing electron microscopy and by enzymatic assays with tritiated cyclic AMP as the substrate. Cytochemical staining showed Physarum's plasmodial phosphodiesterase activity to be located in the nucleus, along the plasma membrane, in vesicles, and free in the cytoplasm. Nuclear phosphodiesterase, which may be cell cycle dependent, was primarily located in the nucleolus. Nuclei from three to five day old microplasmodial cultures were isolated by the method of Henney and Yee. Whole cells were collected through centrifugation and washed. Pellets were homogenized in a …


Plasma Corticosterone Levels In Cholesterol-Fed Cockerels Before And After A Twenty Minute Run, Stanley N. David, Clarene L. David Jan 1986

Plasma Corticosterone Levels In Cholesterol-Fed Cockerels Before And After A Twenty Minute Run, Stanley N. David, Clarene L. David

Journal of the Arkansas Academy of Science

Cockerels were exercised to observe the influence of physical activity on plasma corticosterone concentrations. The birds were maintained on a commercial mash or on an atherogenic diet. Plasmas were collected on the first day, fifteen days after the first collection and immediately after a 20 minute run on that fifteenth day. The plasma corticosterone levels as determined by radioimmunoassay showed extreme variations within collections. Hence, the data analysis indicated no significant changes of the Compound β in the blood of the cockerels due to diet, or exercise or the combination of both. The causes for the wide variation of plasma …


Effects Of Juglone (5'-Hydroxy-1, 4-Naphthoquinone) On The Algae Anabaena Flos-Aquae, Nostoc Commune, And Scenedesmus Acuminatus, V. Diane Randall, Jimmy D. Bragg Jan 1986

Effects Of Juglone (5'-Hydroxy-1, 4-Naphthoquinone) On The Algae Anabaena Flos-Aquae, Nostoc Commune, And Scenedesmus Acuminatus, V. Diane Randall, Jimmy D. Bragg

Journal of the Arkansas Academy of Science

Three species of algae, Anabaena flos-aquae, Nostoc commune and Scenedesmus acuminatus were selected for their sensitivity to juglone and studied for the effects of juglone concentrations of 10, 1, 0.5, 0.1 and 0.01 μg/ml upon their growth. A. flos-aquae was most sensitive, with significant inhibition by the 0.5 μg/ml concentration. N. commune was inhibited least, with significant inhibition only in the 10 μg/ml concentration. S. acuminatus was found to be moderately inhibited at the 0.5 μg/ml concentration. All species were found to be non-viable after 14 days exposure to 10 μg/ml juglone. Tests with 7 and 14 day old cells …


Optimal Conditions For Kinetic Study Of Succinate Dehydrogenase In Rat Liver, Collie B. Shaw, Tara L. Chronister, John D. Peck Jan 1986

Optimal Conditions For Kinetic Study Of Succinate Dehydrogenase In Rat Liver, Collie B. Shaw, Tara L. Chronister, John D. Peck

Journal of the Arkansas Academy of Science

Succinate dehydrogenase (SDH) commonly is assayed as a marker enzyme for mitochondrial activity. The literature presents numerous conditions for conducting this assay due to the fact that, it has been difficult to get sufficient reduction of the acceptor dye, 2,3,5-triphenyl-2H-tetrazolium chloride (TTC). This study was undertaken to optimize the SDH-catalyzed reduction of TTC dye by evaluation of a greater range of molor ratios of TTC to succinate and by further evaluation of additives reported as beneficial. Improvement in enzyme specific activity was achieved by liver perfusion via the left cardiac ventricle with homogenizing solution. Increase in TTC from 1 to …


Formation Of Influenza Virus Particles Lacking Hemagglutinin On The Viral Envelope, Asit K. Pattnaik, Donald J. Brown, Debi P. Nayak Jan 1986

Formation Of Influenza Virus Particles Lacking Hemagglutinin On The Viral Envelope, Asit K. Pattnaik, Donald J. Brown, Debi P. Nayak

School of Veterinary and Biomedical Sciences: Faculty Publications

We investigated the intraceUular block in the transport of hemagglutinin (HA) and the role of HA in virus particle formation by using temperature-sensitive (Is) mutants (1s134 and 1s61S) of inOuenza virus AlWSN/33. We found that at the nonpermissive temperature (39.5°C), the exit of ts HA from the rough endoplasmic reticulum to the Golgi complex was blocked and that no additional block was apparent in either the exit from the Golgi complex or post-Golgi complex transport. When MDBK ceUs were infected with these mutant viruses, they produced noninfectious virus particles at 39.5°C. The efficiency of particle formation at 39.5°C was essentiaUy …


Quantitation And Identification Of Organic N-Chloramines Formed In Stomach Fluid On Ingestion Of Aqueous Hypochlorite, Frank E. Scully Jr., Katherine Mazina, Daniel E. Sonenshine, Frederick Kopfler Jan 1986

Quantitation And Identification Of Organic N-Chloramines Formed In Stomach Fluid On Ingestion Of Aqueous Hypochlorite, Frank E. Scully Jr., Katherine Mazina, Daniel E. Sonenshine, Frederick Kopfler

Biological Sciences Faculty Publications

The chemical reactions that hypochlorite undergoes in the body when chlorinated water is ingested have received very little attention. Because amino nitrogen compounds are important components of the average diet, the reactions of hypochlorite with amino compounds in the stomach were investigated. Stomach fluid was recovered from Sprague-Dawley rats that had been fasted for 48 hr and administered 4 mL deionized water. The chlorine demand of the stomach fluid was determined. An average volume-independent demand of 2.7 mg chlorine was measured. At doses below 40 mg/L chlorine reducing reactions appeared to account for reduction of all oxidizing species within 15 …


Investigation Of Nickle As A Matrix Modifier In The Atomic Absorption Analysis Of Tin, Charles William Saunders Jan 1986

Investigation Of Nickle As A Matrix Modifier In The Atomic Absorption Analysis Of Tin, Charles William Saunders

Chemistry & Biochemistry Theses & Dissertations

Nickel has been widely used as a matrix modifier in the flameless atomic absorption analysis of arsenic and selenium. Its utility as a modifier for tin has been investigated using Polarized Zeeman effect Graphite Furnace Atomic Absorption Spectroscopy. Peak area, peak shape, and appearance times were compared in modified and nonmodified standards using the system computer's internal integration and a detector/readout system with 18 msec resolution.

The addition of nickel at 600 mg/L increased the tin absorbance signal five-fold. The improved signal to noise ratio resulted in a two-fold increase in the sensitivity and a lower limit of detection. The …


Research Note: Getting Graphic: Computer Graphics In Biochemistry, Wilmon B. Chipman Dec 1985

Research Note: Getting Graphic: Computer Graphics In Biochemistry, Wilmon B. Chipman

Bridgewater Review

No abstract provided.


Isolation And Characterization Of Temperature-Sensitive Protein Synthesis Mutants Of Escherichia Coli By Directed Mutagenesis Of The Defective Bacteriophage Lambda Fus2, Kenton L. Lohman Dec 1985

Isolation And Characterization Of Temperature-Sensitive Protein Synthesis Mutants Of Escherichia Coli By Directed Mutagenesis Of The Defective Bacteriophage Lambda Fus2, Kenton L. Lohman

Electronic Theses and Dissertations

Mutagenesis of the defective transducing bacteriophage lambda fus2 was used to isolate a collection of temperature-sensitive mutants of E. coli in the major ribosomal protein gene cluster. Four mutants were examined in detail. Two of the mutants were resistant to the ribosomal antibiotics neamine and spectinomycin. Another mutant was defective in 50S ribosomal subunit assembly at 42(DEGREES)C. The 30S subunit proteins S17 and S19 were changed in two different mutants. Each protein migrated as a more basic species in two-dimensional gels of ribosomal proteins. Ribosomes from each of the four mutants examined showed a temperature-dependent reduction in translational activity in …


Modification Of Chromium(Vi)-Induced Dna Damage By Glutathione And Cytochromes P-450 In Chicken Embryo Hepatocytes., Doreen Y. Cupo, Karen E. Wetterhahn Oct 1985

Modification Of Chromium(Vi)-Induced Dna Damage By Glutathione And Cytochromes P-450 In Chicken Embryo Hepatocytes., Doreen Y. Cupo, Karen E. Wetterhahn

Dartmouth Scholarship

The role of glutathione and cytochrome P-450 in the production of DNA damage by chromium(VI) was examined in chicken embryo hepatocytes by the alkaline elution technique. Cellular levels of glutathione and cytochrome P-450 were altered by treating the hepatocytes with N-acetyl-L-cysteine, buthionine sulfoximine, isopentanol, or beta-naphthoflavone. A dramatic increase in chromium(VI)-induced DNA strand breaks was observed after increasing glutathione levels in the cells. Chromium(VI)-induced DNA strand breaks were even more numerous when the level of cytochrome P-450 was also increased. Upon depletion of glutathione levels and induction of cytochrome P-450 or cytochrome P-448, little or no DNA strand breaks or …


Determination Of Total And Unfilterable Plasma Aluminum In Uremic Patients, Theodore R. Delbridge Oct 1985

Determination Of Total And Unfilterable Plasma Aluminum In Uremic Patients, Theodore R. Delbridge

Chemistry & Biochemistry Theses & Dissertations

Aluminum accumulation in the soft tissues and bone of end stage renal failure patients has been described in the literature. In addition to aluminum normally encountered through ubiquitous sources, these patients are subject to exposures through the dialysate used for hemodialysis and through aluminum-containing phosphate binders. These increased exposures, associated with a decreased ability to excrete aluminum through the kidneys, lead to aluminum accumulation which may result in the onset of an encephalopathy syndrome and/or osteomalacic osteodystrophy. These complications may be very devastating.

Blood serum or plasma aluminum levels do not reflect the total body burden of aluminum. However, they …


Isolation And Characterization Of A Novel Motility Mutant In Salmonella Typhimurium, David Matthew Chacko Sep 1985

Isolation And Characterization Of A Novel Motility Mutant In Salmonella Typhimurium, David Matthew Chacko

Loma Linda University Electronic Theses, Dissertations & Projects

A new mutant, BT40, isolated from mutagenized cultures of S. typhimurium was deficient in chemotaxis (Che- phenotype) in tryptone semisoft agar, but had random motility with a tumbling frequency (37%) similar to that of the parental strain, ST23 (39%). In spatial assays accumulation of BT40 cells in capillary tubes containing attractants was decreased by 33%-59% compared to ST23, but BT40 had a normal response to attractants in temporal assays. The methylation level of the chemotactic proteins was decreased in BT40. At room temperature, the mean swimming speed was 11 μm/s for BT40 and 20 μm/s for ST23; more BT40 …


Choline Inhibition Of Prothrombinase, Richard D. Leach Sep 1985

Choline Inhibition Of Prothrombinase, Richard D. Leach

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to characterize the inhibitory effects of choline on the terminal enzymatic complex of the blood coagulation cascade. Reports in the literature have indicated that choline lengthens whole plasma clotting time with a likely site of inhibition being the step that converts prothrombin (II) to thrombin (IIa).

In order to quantitate the effects of choline on prothrombinase activity, bovine factor V and human factor II were isolated in this laboratory by established methods, and other prothrombinase components were obtained from commercial sources. The activity of venom-activated bovine factor Xa was assayed in the presence of …