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Articles 1081 - 1104 of 1104

Full-Text Articles in Molecular Biology

The Cellular And Molecular Dynamics Of The Queuosine Modification In Transfer Rna: Definition, Modulation, Deficiencies And Effect Of The Queuosine Modification System, Rana C. Morris Jul 1997

The Cellular And Molecular Dynamics Of The Queuosine Modification In Transfer Rna: Definition, Modulation, Deficiencies And Effect Of The Queuosine Modification System, Rana C. Morris

Theses and Dissertations in Biomedical Sciences

The presence of the queuosine modification in the wobble position of tRNAasn, tRNasp, tRNAhis, and tRNAtyr is associated with a decrease in cellular growth rate, an increase in the ability to withstand environmental stress, and differentiation of pleuripotent cells into mature phenotypes. The loss of this normal modification is strongly correlated with neoplastic transformation and tumor progression of a wide variety of cancers.

The "normal" system for formation of the queuosine modification in tRNA was studied in human fibroblast cell cultures and in mouse, rat and human liver tissues. The queuosine modification system …


Oral Cancer Screening, Damon Omar Watson Jun 1997

Oral Cancer Screening, Damon Omar Watson

Honors Theses

Cancers of the oral cavity and pharynx have increased throughout the decades. Since oral cancer represents a small percentage of the total cancers in the United States, it is often overlooked. Though this is the case, the results of this cancer can be devastating. To address this issue, an Oral Cancer Screening was organized on August 14, 1996 at the West Michigan Cancer Center in Kalamazoo. This was a joint collaboration between the author, the West Michigan Cancer Center, and the Kalamazoo Valley Dental Society. This event allowed research to take place concerning the data obtained. Confidential results and information …


An Immunomodulating Mycotoxin Interferes With The Development Of Autoimmune Diabetes In Diabetes-Prone Bb/Wor Rats, Honggang Liu Jan 1997

An Immunomodulating Mycotoxin Interferes With The Development Of Autoimmune Diabetes In Diabetes-Prone Bb/Wor Rats, Honggang Liu

Theses, Dissertations and Capstones

Various fungal products have immunomodulating activity and some have been studied regarding prevention of transplantation rejection. Prior to this investigation, the mycotoxin, gliotoxin (GT), has never been investigated as an immunotherapeutic drug for autoimmune disease. GT is a fungal secondary metabolite and a member of the epipolythiodioxopiperazine (ETP) family which has been shown to inhibit phagocytosis, induction of cytolytic T cells and the proliferation of T cells following mitogen stimulation. GT also induces in vitro apoptosis in certain immune cell types. More importantly, GT exhibits selective activity towards cells of hemopoietic origin.

Autoimmune diseases are disorders caused by immune responses …


Anion Induced Blue To Purple Transition In Bacteriorhodopsin, Mrunalini Pattarkine, Anil K. Singh Jun 1996

Anion Induced Blue To Purple Transition In Bacteriorhodopsin, Mrunalini Pattarkine, Anil K. Singh

Faculty Works

Purple membrane (PM, λ" role="presentation">λmax" role="presentation">max 570 nm) of H. halobium on treatment with sulphuric acid changes its colour to blue (λ" role="presentation">λmax" role="presentation">max 608 nm). The purple chromophore can be regenerated from the blue chromophore by exogeneous addition of anions such as CI−" role="presentation">− and HPO42−" role="presentation">2−4. Chloride ion is found to be more effective than the dibasic phosphate ion in regenerating the purple chromophore. Nevertheless, one thing common to the anion regeneration is that both CI−" role="presentation">− and HPO42−" role="presentation">2−4 show marked pH effect. At pH 1.0 the efficiency of …


Regulation Of Melanogenesis In B16 Mouse Melanoma Cells By Protein Kinase C (Pkc), Harish Mahalingam Jan 1996

Regulation Of Melanogenesis In B16 Mouse Melanoma Cells By Protein Kinase C (Pkc), Harish Mahalingam

Theses, Dissertations and Capstones

The pigment cell-specific expression of tyrosinase and TRP1 has been shown to be important for the production of melanin in pigmented cells. Using a pigmented cell line, B16 mouse melanoma, we obtained evidence that PKC plays a major role in regulating melanogenesis. Chronic treatment with phorbol dibutyrate (PDBu) leads to downregulation of PKC activity and protein levels. This is accompanied by a loss of pigmentation which is correlated with a 50% reduction and a complete loss of TRP1 and tyrosinase respectively. Similar results were obtained with Northern and Western blotting indicating that PKC may regulate the steady state levels of …


Biochemical And Molecular Characterization Of The Prostate-Specific Membrane Antigen (Psma), John Karl Troyer Oct 1995

Biochemical And Molecular Characterization Of The Prostate-Specific Membrane Antigen (Psma), John Karl Troyer

Theses and Dissertations in Biomedical Sciences

Prostate cancer is the most common malignancy and the second leading cause of cancer death in males in the United States. Additionally, the number of deaths attributed to prostate cancer is increasing at a rate of approximately 8% a year. Development of new diagnostic and therapy strategies are needed in order to improve the life expectancy of patients with this disease. One tool which may allow for improvements in prostate cancer diagnosis and therapy is the monoclonal antibody (MAb) 7E11-C5.3 which was first described in 1987. Since then, the antigen recognized by MAb 7E11-C5.3 has been named the prostate specific …


Identification And Characterization Of Mitochondrial Dna Variants In Alzheimer's Disease, Natasha Singh Hamblet Jul 1995

Identification And Characterization Of Mitochondrial Dna Variants In Alzheimer's Disease, Natasha Singh Hamblet

Theses and Dissertations in Biomedical Sciences

Alzheimer's Disease (AD) is a complex neurodegenerative disorder that affects a significant portion of the human population regardless of ethnicity or gender. A mitochondrial hypothesis of AD has been proposed based on a number of studies which establish altered oxidative phosphorylation (OXPHOS) and ATP synthesis in AD tissue. ATP demand is most prevalent in the brain; damage to OXPHOS could severely impair brain metabolism, thereby leading to a decline in cognitive function. Four out of five complexes in the OXPHOS pathway are partly encoded by mitochondrial DNA (mtDNA); thus, this may be a crucial site of lesions that alter brain …


In Vitro Expression Of Human Zona Pellucida Protein 3, Chih-Wei Chen Jul 1995

In Vitro Expression Of Human Zona Pellucida Protein 3, Chih-Wei Chen

Theses and Dissertations in Biomedical Sciences

Human zona pellucida protein 3 (hZP3) is the putative receptor on the zona pellucida of the mature oocyte that recognizes and binds sperm, and therefore plays a critical role in fertilization.

A full length cDNA of hZP3 (1278 bp) was amplified from the human ovary mRNA by reverse transcription-polymerase chain reaction (RT-PCR). The hZP3 cDNA was subcloned into PSK and pREP4 expression vectors. The cDNA of hZP3 was further characterized by restriction mapping, PCR, auto-sequencing and Southern blot analysis by using an internal oligonucleotide probe, and found to be identical to the one reported by J. Dean. Using autosequencing, 289 …


Moraxella (Branhamella) Catarrhalis: A Molecular Epidemiology Study, Lyndell R. Gill May 1995

Moraxella (Branhamella) Catarrhalis: A Molecular Epidemiology Study, Lyndell R. Gill

Electronic Theses and Dissertations

Moraxella (Branhamella) catarrhalis is the third-most-frequently isolated microorganism associated with acute exacerbations of chronic bronchitis in patients during their stay at the Mountain Home VA Medical Center (MHVAMC). In order to develop a practical, epidemiologically-meaningful typing method for M. (B.) catarrhalis, we tested two methods based on analysis of chromosomal DNA for typeability, reproducibility, and ability to differentiate between unrelated strains (discriminatory power, D). M. (B.) catarrhalis isolants from MHVAMC from 7/1/87-6/30/88 were grown overnight in broth and embedded in agarose. DNA was isolated by standard methods. The DNA was subjected to: (1) restriction endonuclease digestion (with either Bgl II …


The Kinetic Characterization Of Mutant L289p Of Recombinant Hiv-1 Reverse Transcriptase, Tryn Thomas Stimart Apr 1995

The Kinetic Characterization Of Mutant L289p Of Recombinant Hiv-1 Reverse Transcriptase, Tryn Thomas Stimart

Chemistry & Biochemistry Theses & Dissertations

The Human Immunodeficiency Virus, type 1 (HIV-1) is the causative agent of the Acquired immunodeficiency Syndrome (AIDS). Currently, AIDS is the leading cause of death amongst young people in the United States. The large increase of HIV-1 infections over the past decade has spawned considerable research in fighting the spread of this disease. One area of intense HIV-1 research has focused on the enzyme Reverse Transcriptase (RT) which is an essential enzyme involved in the replication and life cycle of HIV-1. HIV-1 RT is composed of p66 and p51 subunits and is only active as a heterodimer in vivo. …


Biotransformation Of Bile Acids, Cholesterol And Steroids. Chapter 13 In: The Ecology And Physiology Of Gastrointestinal Microbes. Vol. 1, New York, Chapman And Hall., Stephen Baron, Phillip B. Hylemon Jan 1995

Biotransformation Of Bile Acids, Cholesterol And Steroids. Chapter 13 In: The Ecology And Physiology Of Gastrointestinal Microbes. Vol. 1, New York, Chapman And Hall., Stephen Baron, Phillip B. Hylemon

Biology Faculty Scholarship

No abstract provided.


An Analysis Of Mitochondrial Dna In Rett Syndrome And Other Neurodegenerative Disorders, Catherine Erickson Burgess Jan 1994

An Analysis Of Mitochondrial Dna In Rett Syndrome And Other Neurodegenerative Disorders, Catherine Erickson Burgess

Theses and Dissertations in Biomedical Sciences

Mitochondrial dysfunction resulting from mutations on mitochondrial DNA (mtDNA) is being recognized in a growing spectrum of diseases. These diseases, resulting from single base mutations, large deletions, or insertions, have been largely neuromuscular in origin. However, as an understanding of the effects of mtDNA mutations progresses, attention is now focusing on neurodegenerative diseases. Rett Syndrome (RS), a progressive neurodegenerative disease with predominantly female cases, demonstrates morphologic mitochondrial changes, mitochondrial enzyme deficiencies and maternal inheritance (characteristic of mtDNA diseases). No investigation of mtDNA involvement has been previously conducted and, to date, no biological marker exists for this disorder.

Our preliminary studies …


Separation And Quantification Of Queuine-Modified And Unmodified Transfer Rna Isoacceptors, Jorge Miguel Pereira De Oliveira Da Silva Santos Apr 1993

Separation And Quantification Of Queuine-Modified And Unmodified Transfer Rna Isoacceptors, Jorge Miguel Pereira De Oliveira Da Silva Santos

Chemistry & Biochemistry Theses & Dissertations

The discovery of a base-exchange modification in the first position of the anticodon of four transfer RNA (tRNA) isoacceptor families has been shown to be correlated with a decrease in the rate of cell division in several tumorigenic tissues. This fact led to the hypothesis that wobbling in the anticodon might be a control point wich mediates the rate of translation. A suitable method for separation of different tRNA isoacceptor families had to be created in order to generate a means for quantitatively measuring degrees of this base modification in tRNA. Radio labelled amino acids were used to charge tRNA …


Laminin Potentiates Differentiation Of Pcc4uva Embryonal Carcinoma Into Neurons, T. M. Sweeney, Roy C. Ogle, C. D. Little Sep 1990

Laminin Potentiates Differentiation Of Pcc4uva Embryonal Carcinoma Into Neurons, T. M. Sweeney, Roy C. Ogle, C. D. Little

School of Medical Diagnostics & Translational Sciences Publications

The embryonal carcinoma PCC4uva differentiates into neurons in response to treatment with retinoic acid and dbcAMP. We used this in vitro model system to study the effects of laminin on early neural differentiation. Laminin substrata markedly potentiate neural differentiation of retinoic acid and dbcAMP-treated cultures. Only laminin induced more rapid neural cell body clustering, neurite growth and neurite fasciculation as compared to type IV collagen, type I collagen, and fibronectin substrata. Exogenous laminin substrata promoted greater cell attachment, cellular spreading and growth to confluence than type IV collagen, type I collagen, fibronectin and glass substrata. Laminin-induced effects were inhibited by …


Progesterone And 17 Α-Hydroxyprogesterone: Novel Stimulators Of Calcium Influx In Human Sperm, Peter F. Blackmore, Stephen J. Beebe, Douglas R. Danforth, Nancy Alexander Jan 1990

Progesterone And 17 Α-Hydroxyprogesterone: Novel Stimulators Of Calcium Influx In Human Sperm, Peter F. Blackmore, Stephen J. Beebe, Douglas R. Danforth, Nancy Alexander

Bioelectrics Publications

Progesterone and 17 alpha-hydroxyprogesterone (but not other steroids such as testosterone, corticosterone, beta-estradiol, estrone, dehydroepiandrosterone, 20 alpha-hydroxypregnen-3-one, androstenedione, and pregnenolone) were shown to cause an immediate increase, in free cytosolic calcium ([Ca2+]i) in both capacitated and noncapacitated human sperm, using the fluorescent indicator fura 2. Significant increases in [Ca2+]i were observed with 10 ng/ml progesterone, while maximum effects were seen with 1 microgram/ml progesterone. Two other steroids 11 beta-hydroxyprogesterone and 5 alpha-pregnane-3,20-dione exhibited significant activity to increase [Ca2+]i. This increase in [Ca2+]i elicited by progesterone was entirely due to Ca2+ influx from the extracellular medium since the increase in [Ca2+]i …


Regulation Of Queuine Insertion Into Transfer Rna: Effects Of Tumor Promoters, Bonnie Jean Brooks Oct 1989

Regulation Of Queuine Insertion Into Transfer Rna: Effects Of Tumor Promoters, Bonnie Jean Brooks

Chemistry & Biochemistry Theses & Dissertations

The purpose of this study was to treat normal human fibroblasts with known tumor promoters and observe queuine modification of tRNA. The queuine insertion enzyme, tRNAguanine ribosyltransferase, was studied in vivo and in vitro. Tumor promoter-treated human fibroblast cultures exhibited variable queuine-insertion rates with a transient inhibition that correlated with variable levels of queuine modified tRNA over time in culture from passages 3 — 8. In contrast the in vitro studies showed that phorbol cetera and saccharin actually increased insertion with strong evidence indicating phosphorylation as a positive modulating force of the enzyme activity. It is proposed that chronic stimulation …


Microwell Based Competitive Enzyme Immunoassay For Quantifying Serum Triiodothyronine And Thyroxine Levels, Yiwen Yang Jul 1989

Microwell Based Competitive Enzyme Immunoassay For Quantifying Serum Triiodothyronine And Thyroxine Levels, Yiwen Yang

Chemistry & Biochemistry Theses & Dissertations

A microwell based competitive enzyme immunoassay for determination of total thyroxine and triiodothyronine in human serum was developed with use of horseradish peroxidase conjugate. The assay, which can be performed in only 1.5 hours at room temperature, involves simultaneous incubation of T3- or T4- HRPO conjugate and serum sample in anti-T3 or anti-T4 gamma globulin fraction coated polystyrene microwells.

Isolation of anti-T3 and anti-T4 gamma globulin fractions were accomplished from whole antiserum by using DEAE-cellulose chromatograph. A carbodiimide coupling method was described to prepare the T4- and T3-HRPO …


Collagen Binding Proteins Derived From The Embryonic Fibroblast Cell Surface Recognize Arginine-Glycine-Aspartic Acid, Roy C. Ogle, Charles D. Little Jun 1989

Collagen Binding Proteins Derived From The Embryonic Fibroblast Cell Surface Recognize Arginine-Glycine-Aspartic Acid, Roy C. Ogle, Charles D. Little

School of Medical Diagnostics & Translational Sciences Publications

Several cell surface proteins (Mr = 120,000, 90,000, 63,000 and 47,000) apparently integral to embryonic fibroblast plasma membranes were extracted with detergent and isolated by collagen affinity chromatography. Certain of these proteins (Mr = 120,000, 90,000, and 47,000) were specifically eluted from collagen affinity columns by synthetic peptides containing the amino acid sequence arginyl-glycyl-aspartic acid (RGD). These data show that a number of collagen binding proteins exist on the embryonic fibroblast cell surface. Some of the proteins may be collagen receptors binding to RGD sequences in the collagen molecule while at least one of the proteins (Mr = 63,000) recognizes …


Hypoxanthine-Induced Differentiation Of Cultured Human Leukemia Cells, Gayle Jennette Singleton Apr 1989

Hypoxanthine-Induced Differentiation Of Cultured Human Leukemia Cells, Gayle Jennette Singleton

Chemistry & Biochemistry Theses & Dissertations

Human cultured leukemia cells appear to have a decreased amount of inosine in their tRNA. When cells with inosine deficient tRNA are placed in a hypoxanthine fortified media, they incorporate hypoxanthine into their tRNA by the action of the enzyme tRNA-hypoxanthine ribosyl transferase. This generates the nucleoside inosine in the tRNA. The cultured human leukemia cell lines, CCRF-CEM, HL-60, and HGPRT(-) HL- 60, incorporate hypoxanthine into their tRNA, as determined by tRNA isolation, hydrolysis, and HPLC analysis. Hypoxanthine treatment dramatically inhibited cell growth in conjunction with partial induction of differentiation in the CCRF-CEM, HL-60, and HGPRT ( - ) HL-60 …


Isolation And Partial Characterization Of Basic, Sperm-Specific, Nuclear Proteins In The Dog And Hampster, Richard William Hall Apr 1989

Isolation And Partial Characterization Of Basic, Sperm-Specific, Nuclear Proteins In The Dog And Hampster, Richard William Hall

Biological Sciences Theses & Dissertations

The purpose was to determine whether dogs and hamsters contain the same sperm-specific protamine and testis specific proteins (TP) as other eutherian mammals previously studied. The proteins (protamine and TPs) were isolated from spermatids and mature spermatozoa, and were subjected to electrophoresis in an acid-urea, polyacrylamide gel system according to the procedure of Panyim and Chalkley (1962). The results indicated that, regardless of the anatomical location of sperm acquisition, acid precipitation technique, or denaturing agents used, epididymal and testicular samples from both the dog and hamster contained protamine in elongated spermatids and mature spermatozoa. The protamines from dogs and hamsters …


A Method For The Large Scale Purification Of Hcg (Human Chorionic Gonadotropin) From The Urine Of Pregnant Women, Chun-Shyan Kuo Oct 1988

A Method For The Large Scale Purification Of Hcg (Human Chorionic Gonadotropin) From The Urine Of Pregnant Women, Chun-Shyan Kuo

Chemistry & Biochemistry Theses & Dissertations

A large scale preparation of human chorionic gonadotropin (HCG) from the urine of pregnant women was accomplished by using kaolin adsorption, NH4OH extraction and DEAE-cellulose ion exchange. A recovery about 81% of HCG and a specific activity in the 2,000-3,000 IU/mg range was achieved using this purification method.

Two HCG activity fractions, HCG I & HCG II, were isolated from DEAE-cellulose chromatography by a stepwise sodium chloride gradient elution. HCG I was eluted at 0.01-0.02 M NaCl while HCG II was eluted at 0.12-0.02 M NaCl.

The differences between HCG I and HCG II have been studied. The …


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 …


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 …


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 …