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Articles 1651 - 1665 of 1665

Full-Text Articles in Molecular Biology

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

Medical Diagnostics & Translational Sciences Faculty 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 …


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 …


Biochemical And Histological Evaluation Of Normal Human Epidermis Vs Cultured Human Epidermis, Ngo Thi Bich Lien Jan 1987

Biochemical And Histological Evaluation Of Normal Human Epidermis Vs Cultured Human Epidermis, Ngo Thi Bich Lien

Biological Sciences Theses & Dissertations

Cultured human keratinocytes were grown in vitro for transplantation purposes in case of severe burns. Single keratinocytes were harvested from human epidermis and grown in culture flasks such that multilayered sheets of keratinocyte cells were harvestable in approximately three weeks. In order to evaluate cultured epidermis for equivalency with normal human epidermis, biochemical and histological studies were performed. Thin sections of cultured epidermis were shown to be composed of cells that had undergone developmental differentiation, but not terminal differentiation. Biochemical analyses of keratin and prekeratin proteins isolated from cultured epidermis indicated that cultured keratinocytes have electrophoretic patterns similar to keratins/prekeratins …


Comparison Of Surface Polysaccharides Of R. Leguminosarum Anu57 (Exo-1), R. Leg. Anu57(Pbr1an) (Nod+, Nif-), And R. Leg. Anu57(Pjb5j1) (Nod+, Nif-), Frank G. Hustmyer Jan 1984

Comparison Of Surface Polysaccharides Of R. Leguminosarum Anu57 (Exo-1), R. Leg. Anu57(Pbr1an) (Nod+, Nif-), And R. Leg. Anu57(Pjb5j1) (Nod+, Nif-), Frank G. Hustmyer

Masters Theses

Extracellular polysaccharides (EPS) and lipopolysaccharides (LPS) are suspected to be involved in the legume/Rhizobium symbiotic process. Polysaccharide compositions from the EPS, LPS, capsular polysaccharide (CPS), and small polysaccharide (SmPS) were compared between Rhizobium leguminosarum ANU57 (parent, Exo-1) and two mutants R. leg. ANU57(pBR1AN) (nod+, nif-) and R. leg. ANU57(pJB5J1) (nod+, nif-) both containing a Sym (symbiotic) plasmid insertion. R. leg. ANU57(pBR1AN) and R. leg. ANU57(pJB5J1) are nod+ on clover and peas, respectively. The nod+ mutants produce larger amounts of EPS and decreased amounts of LPS compared to …


Determination Of Erythrocyte Zinc Concentrations Using Zeeman Effect Atomic Absorption Spectroscopy, Tanya Maranda Lewis Jul 1983

Determination Of Erythrocyte Zinc Concentrations Using Zeeman Effect Atomic Absorption Spectroscopy, Tanya Maranda Lewis

Chemistry & Biochemistry Theses & Dissertations

The purpose of this research project was to develop assay procedures for determination of zinc in erythrocytes. Three methodologies were developed. The methods were evaluated on the basis of within-run and between-run precision. The most reproducible method, the 213.856 nm flame methodology, was used to determine red blood cell zinc concentrations in more than 200 samples obtained from the Neonatal Intensive care Unit at the Children's Hospital of the King's Daughters.

This study demonstrated that erythrocyte zinc levels in premature infants were similar to those of healthy adults. A linear relation between plasma and red blood cell zinc concentrations was …


Distribution Of Limonin During The Growth And Development Of Leaves And Branches Of Citrus Paradisi, Cecilia Mcintosh, Richard L. Mansell Feb 1983

Distribution Of Limonin During The Growth And Development Of Leaves And Branches Of Citrus Paradisi, Cecilia Mcintosh, Richard L. Mansell

Cecilia A. McIntosh

This report analyzes the distribution of limonin within a leaf, within a branch, and between branches of an individual Citrus paradisi tree.  Limonin was evenly distributed within single leaves and the concentration in the leaves on a given branch was constant, regardless of branch age.  The total amount of limonin per leaf varied with leaf size.  Not all branches within the tree exhibited the same potential for limonin metabolism as reflected in their limonin and limonoate A-ring monolactone levels.  The limonin content showed increasing levels as the leaves bud and grow and then decreasing levels as they mature and turn …


An Analysis Of The Limonin And Naringin Content Of Grapefruit Juice Samples Collected From Florida State Test Houses, Richard L. Mansell, Cecilia Mcintosh, Susan E. Vest Dec 1982

An Analysis Of The Limonin And Naringin Content Of Grapefruit Juice Samples Collected From Florida State Test Houses, Richard L. Mansell, Cecilia Mcintosh, Susan E. Vest

Cecilia A. McIntosh

An analysis of the limonin and naringin content of 6685 grapefruit juice samples (representing approximately 6% of all grapefruit harvested) collected from three Florida State Test Houses showed that there were statistically significant differences between the Test Houses.  There also was a statistically significant difference in the concentration of these compounds in the juice from the different cultivars of fruit sampled.  Average limonin and naringin concentrations in the juice remained fairly constant through the beginning of the season until a freeze occurred in early 1981.  Juice obtained from fruit harvested after this freeze contained decreasing amounts of limonin and increasing …


Isomers Of 5.8s Ribosomal Rna, David Smith Jul 1982

Isomers Of 5.8s Ribosomal Rna, David Smith

Chemistry & Biochemistry Theses & Dissertations

When whole cell RNA was separated by high resolution PAG (i.e., polyacrylamide gel) electrophoresis, 5.8S rRNA migrated as three higher mobility intense bands, and three faint bands of lower mobility. The three intense bands represent conformational isomers which migrated as a single band under denaturing conditions on PAG. The three faint bands represent conformational isomers of a minor form of 5.8S rRNA which is elongated at the 5' terminus of the molecule. This minor form migrates as a single band of lower mobility than the major form when electrophoresed on a denaturing PAG. The minor form was determined to have …


Distribution Of Limonin In The Fruit Tissues Of Nine Grapefruit Cultivars, Cecilia Mcintosh, Richard L. Mansell, Russell L. Rouseff Jun 1982

Distribution Of Limonin In The Fruit Tissues Of Nine Grapefruit Cultivars, Cecilia Mcintosh, Richard L. Mansell, Russell L. Rouseff

Cecilia A. McIntosh

This report presents the results of a study conducted to determine the distribution of limonin within the fruit tissues of nine grapefruit cultivars.  It was found that the highest limonin levels within the fruit tissues were found in the cotyledon, followed by inner seed coat, outer seed coat, central pith, segment membrane, albedo and flavedo, and juice vesicles, in decreasing amounds.  The concentration of limonin in the tissues of the individual cultivars is also presented, and the variation in limonin content within a single tissue and within single fruit is discussed.  The limonin content of the fruit of the nine …


Functions Of Deadenylation Factors In Mrna Decay And Mrna Processing Body Formation, Dinghai Zheng Sep 1980

Functions Of Deadenylation Factors In Mrna Decay And Mrna Processing Body Formation, Dinghai Zheng

Dissertations & Theses (Open Access)

Most newly synthesized messenger RNAs possess a 5’ cap and a 3’ poly(A) tail. The process of poly(A) tail shortening, also termed deadenylation, is important for post-transcriptional gene regulation, because deadenylation not only leads to mRNA translational inhibition but also is the first step of major mRNA degradation. Translationally inhibited mRNAs can be stored and/or degraded in dynamic cytoplasmic foci termed mRNA processing bodies, or P bodies, which are conserved in eukaryotes.

To shed new light on the mechanisms of P body formation and P body functions, I focused on the link between deadenylation factors and P bodies. I found …


High Resolution Two-Dimensional Electrophoretic Study Of Human Seminal Plasma Proteins, Edward E. Gaunt Jul 1980

High Resolution Two-Dimensional Electrophoretic Study Of Human Seminal Plasma Proteins, Edward E. Gaunt

Chemistry & Biochemistry Theses & Dissertations

A comprehensive biochemical screening procedure for the evaluation of seminal plasma constituents is needed which, when used in conjunction with semen analysis, can provide the physician with both qualitative and quantitative information regarding the fertility status of an individual.

High resolution two-dimensional electrophoresis is a technique whereby proteins in a complex mixture such as a biological fluid are separated in one dimension by molecular charge and in the second dimension by molecular mass. It has been the purpose of this investigation to adapt and evaluate this technique for the analysis of human seminal plasma.

Our efforts have shown that this …


Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky Jan 1980

Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky

Faculty Publications, Biological Sciences

A somatic cell mutant (CR1) of a Chinese hamster ovary cell (CHO-K1) which has previously been shown to be defective in the regulation of cholesterol biosynthesis accumulates more cholesterol than the parental cell line in plasma membranes. Although such an increase in membrane cholesterol should lead to an increase in the order parameter of these membranes, as measured with an electron spin resonance spin probe, the order parameters of mutant and wild-type plasma membranes are identical--apparently because of an adaptive alteration in membrane phospholipid composition. The phospholipid compositions of mutant and wild-type cell plasma membranes are compared and the mutant …


Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky Jan 1980

Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky

Michael Sinensky

A somatic cell mutant (CR1) of a Chinese hamster ovary cell (CHO-K1) which has previously been shown to be defective in the regulation of cholesterol biosynthesis accumulates more cholesterol than the parental cell line in plasma membranes. Although such an increase in membrane cholesterol should lead to an increase in the order parameter of these membranes, as measured with an electron spin resonance spin probe, the order parameters of mutant and wild-type plasma membranes are identical--apparently because of an adaptive alteration in membrane phospholipid composition. The phospholipid compositions of mutant and wild-type cell plasma membranes are compared and the mutant …


Multiple Methods Of Analysis Of 2'-O-Methylation In 5.8s Rrna, Sharon H. Ryan Jan 1980

Multiple Methods Of Analysis Of 2'-O-Methylation In 5.8s Rrna, Sharon H. Ryan

Chemistry & Biochemistry Theses & Dissertations

5.8S rRNA is a low molecular weight ribosomal RNA which is found hydrogen bonded to 28S rRNA in the eucaryotic cell. There are two nucleotides which have 2'-0-methylations; a guanine residue at position 77 is fully methylated and a uridine residue at position 14 which is partially methylated. This partial 2'-0-methylation of the uridine residue has been found to vary with the tissue source, with the highest level in normal tissue and the lowest level in neoplastic tissue. In order to study the significance of this site-specific methylation, a reliable and convenient method of analysis was needed.

Early studies on …


The Association Of 5.8 S With 28s Ribosomal Rna, Nandita Banerjee Jan 1980

The Association Of 5.8 S With 28s Ribosomal Rna, Nandita Banerjee

Chemistry & Biochemistry Theses & Dissertations

5.8S rRNA is a low molecular weight ribosomal RNA which is noncovalently bonded to the larger ribosomal subunit 28S rRNA; through its 3' end and through its 5' end. This interaction is an integral part of the ribosome, and plays an important role in the ribosome structure and function.

There is a high degree of homology between the 5.8S rRNA primary structures of rat, turtle and chicken. The base sequence of rat 5.8S rRNA differs only in one position from that of turtle and in three positions fr.om that of cl1.icken. Tl1ere is a single purine substitution at the 5' …