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Articles 3571 - 3600 of 3639

Full-Text Articles in Cell Biology

Dark Repair Of Lethal Damage Induced In A Hybrid Mammalian Tissue Culture Cell Line By Ultraviolet Light, Robin Haetten, Margaret Mcguinness, H. Gaston Griggs Jan 1982

Dark Repair Of Lethal Damage Induced In A Hybrid Mammalian Tissue Culture Cell Line By Ultraviolet Light, Robin Haetten, Margaret Mcguinness, H. Gaston Griggs

Journal of the Arkansas Academy of Science

No abstract provided.


Electron Microscopic Demonstration Of Neural Connections Using Horseradish Peroxidase: A Comparison Of The Tetramethylbenzidine Procedure With Seven Other Histochemical Methods, Keith A. Carson, M-Marsel Mesulam Jan 1982

Electron Microscopic Demonstration Of Neural Connections Using Horseradish Peroxidase: A Comparison Of The Tetramethylbenzidine Procedure With Seven Other Histochemical Methods, Keith A. Carson, M-Marsel Mesulam

Biological Sciences Faculty Publications

Eight methods for the electron microscopic demonstration of horseradish peroxidase (HRP) labeling have been compared in adjacent series of vibratome sections of mouse lumbar spinal cord. The tracer, a HRP-wheat germ agglutinin (WGA) conjugate, was injected into the gastrocnemius muscle complex. Following retrograde axonal transport to the lumbar motor neurons and transganglionic anterograde transport of the tracer to the dorsal horn, the HRP activity was demonstrated in eight series of adjacent sections of lumbar spinal cord using eight methods. These included procedures using tetramethylbenzidine (TMB), benzidine dihydrochloride (BDHC), o-tolidine, paraphenylenediamine-pyrocatechol (PPD-PC), and 4 methods using 3,3'-diaminobenzidine (DAB). All ...


Kepone Toxicity To Estuarine Microorganisms, William Richard Mahaffey Jun 1981

Kepone Toxicity To Estuarine Microorganisms, William Richard Mahaffey

Biology Master’s Theses

Synthesized chemical agents can have an unseen, and yet profound, impact on the environment in which it is used. This study investigates the effects of the insecticide Kepone (99% pure) on estuarine microbial populations and seeks to determine the mode of toxicity to pure culture isolates obtained therein. The researcher used disc agar diffusion sensitivity, plate counts, and oxygen uptake methods to collect data over a period of four months to determine the toxicity of Kepone to a variety of laboratory pure cultures of bacteria and fungi. Of the 30 isolates tested, 33% were inhibited at 3.65 μg/disc ...


Studies On The Effect Of Azaserine On Dna, Charles Zucker Apr 1981

Studies On The Effect Of Azaserine On Dna, Charles Zucker

Life and Environmental Sciences Undergraduate Theses

Azaserine (O-diazoacetyl-L-serine) is known to be a non-competitive inhibitor of two enzymes necessary for de novo purine biosynthesis. Work done in this laboratory and others, however, indicates that much of azaserine’s effect in cytotoxicity, mutagenesis and carcinogenesis can be attributed to its action on DNA. DNA repair-deficient strains of Escherichia coli are found to be more sensitive to azaserine cytotoxicity and, in cases, to azaserine mutagenesis than the wild type E. coli. Attempts at showing an in vitro effect of azaserine on DNA have not been conclusive as of yet. An interesting aspect of azaserine cytotoxicity is that it ...


Spectrin Promotes The Association Of F-Actin With The Cytoplasmic Surface Of The Human Erythrocyte Membrane, V. M. Fowler, Elizabeth J. Luna, W. R. Hargreaves, D. L. Taylor, D. Branton Feb 1981

Spectrin Promotes The Association Of F-Actin With The Cytoplasmic Surface Of The Human Erythrocyte Membrane, V. M. Fowler, Elizabeth J. Luna, W. R. Hargreaves, D. L. Taylor, D. Branton

Women’s Health Research Faculty Publications

We studied the binding of actin to the erythrocyte membrane by a novel application of falling ball viscometry. Our approach is based on the notion that if membranes have multiple binding sites for F-actin they will be able to cross-link and increase the viscosity of actin. Spectrin- and actin-depleted inside-out vesicles reconstituted with purified spectrin dimer or tetramer induce large increases in the viscosity of actin. Comparable concentrations of spectrin alone, inside-out vesicles alone, inside-out vesicles plus heat-denatured spectrin dimmer or tetramer induce large increases in the viscosity of actin. Comparable concentrations of spectrin alone, inside-out vesicles alone, inside-out plus ...


A Membrane Cytoskeleton From Dictyostelium Discoideum. I. Identification And Partial Characterization Of An Actin-Binding Activity, Elizabeth J. Luna, V. M. Fowler, J. Swanson, D. Branton, D. L. Taylor Feb 1981

A Membrane Cytoskeleton From Dictyostelium Discoideum. I. Identification And Partial Characterization Of An Actin-Binding Activity, Elizabeth J. Luna, V. M. Fowler, J. Swanson, D. Branton, D. L. Taylor

Women’s Health Research Faculty Publications

Dictyostelium discoideum plasma membranes isolated by each of three procedures bind F-actin. The interactions between these membranes and actin are examined by a novel application of falling ball viscometry. Treating the membranes as multivalent actin-binding particles analogous to divalent actin-gelation factors, we observe large increases in viscosity (actin cross-linking) when membranes of depleted actin and myosin are incubated with rabbit skeletal muscle F-actin. Pre-extraction of peripheral membrane proteins with chaotropes or the inclusion of Triton X-100 during the assay does not appreciably diminish this actin cross-linking activity. Lipid vesicles, heat-denatured membranes, proteolyzed membranes, or membranes containing endogenous actin show minimal ...


Forms Of Phosphorus In Nutrition Of Halobacterium Halobium And Halobacterium Salinarium, Pramodbala Parekh Jan 1981

Forms Of Phosphorus In Nutrition Of Halobacterium Halobium And Halobacterium Salinarium, Pramodbala Parekh

Theses Digitization Project

No abstract provided.


Ultra Structure Of Cell Division In The Unicellular Red Alga Porphyridium Purpureum, Kathleen L. Schornstein Jan 1981

Ultra Structure Of Cell Division In The Unicellular Red Alga Porphyridium Purpureum, Kathleen L. Schornstein

Dissertations, Theses, and Masters Projects

No abstract provided.


Temperature-Dependency Of Transformation And Cell Cycle Length In Human Lymphocytes, John Patrick Mcgee Jan 1981

Temperature-Dependency Of Transformation And Cell Cycle Length In Human Lymphocytes, John Patrick Mcgee

Dissertations, Theses, and Masters Projects

No abstract provided.


H+ And K+ Transport In Nitella, Daniel John Holland Aug 1980

H+ And K+ Transport In Nitella, Daniel John Holland

Biology Master’s Theses

This study attempts to determine if a fixed stoichiometry of the K+­­/H+ exchange is present in Nitella clavata. Nitella was cultured with constant aeration under illumination of approximately 2000 lux measured at the culture solution surface, with sixteen hours of illumination alternated with eight hours of darkness. Internodal cells were harvested by excision, with harvested cells ranging from 3-5 cm in length and 700-900 μm in diameter. Isolated cells were then placed in a 5.70 pH K solution and kept in an incubator at 22°C under 350 lux illumination. Cells were preconditioned for seven days before experimentation ...


The Effect Of Colchicine On Sexual Reproduction Of Chlamydomonas Moewusii, Anne Leslie Menoff May 1980

The Effect Of Colchicine On Sexual Reproduction Of Chlamydomonas Moewusii, Anne Leslie Menoff

Biology Master’s Theses

The effect of colchicine on the mating reaction in Chlamydomonas moewusii was investigated. Five mM colchicine was found to cause a 96% inhibition of gamete fusion, without disrupting the preceding agglutination reaction or cell motility. Electron microscope examination of colchicine-treated gametes revealed a 98% inhibition of mating structure activation, suggesting that the drug had rendered the gametes incapable of generating and/or responding to the signal for mating structure activation which normally accompanies sexual agglutination. Light microscope analysis revealed that flagella of adhering drug-treated cells entwined loosely so that treated gametes were unable to establish the flagella tip alignment, and ...


The Uptake Of Dehydroascorbate In The Polymorphonuclear Leucocytes Of The Diabetic Vs Non-Diabetic Individual, Michael Hegewald Apr 1980

The Uptake Of Dehydroascorbate In The Polymorphonuclear Leucocytes Of The Diabetic Vs Non-Diabetic Individual, Michael Hegewald

Life and Environmental Sciences Undergraduate Theses

The uptake of dehydroascorbate (DHA) was studied in both diabetic and non-diabetic polymorphonuclear leucocytes (PMN). The mean uptake of DHA was found to be lower in the diabetic than non-diabetic group. The uptake of DHA was also lower when PMN were incubated in a final concentration of 3 mg/ml glucose instead of 1 mg/ml glucose. There appears to be an inverse relationship between glucose concentration and DHA uptake in PMN; that is, when glucose levels are increased, DHA uptake is decreased. This may cause the accumulation of DHA in diabetic plasma and contribute to the complications of diabetes.


Cell Wall Synthesis In The Dimorphic Fungus Mucor Rouxii: The Formation Of Uridine Diphosphohexoses, John Witte Apr 1980

Cell Wall Synthesis In The Dimorphic Fungus Mucor Rouxii: The Formation Of Uridine Diphosphohexoses, John Witte

Life and Environmental Sciences Undergraduate Theses

In this paper the properties of the enzymes UDP glucose dehydrogenase and UDP galactose epimerase were characterized. It was shown that UDP glucose dehydrogenase has a considerable lag period, and is activated by the substrate UDP glucose. This activation may be brought about by a disaggregation. Both enzymes were shown to be labile. For accurate kinetic measurements the dehydrogenase must be separated from the epimerase. The UDP galactose epimerase showed no requirements for exogenous NAD+ and demonstrated slight positive cooperativity for UDP galactose. Experiments were carried out in order to determine the specific activity of UDP glucose dehydrogenase during a ...


The Osmotic Fragility Of Red Blood Cells Of Marine Animals: A Comparative Study, Robert Demanche Jan 1980

The Osmotic Fragility Of Red Blood Cells Of Marine Animals: A Comparative Study, Robert Demanche

Dissertations, Theses, and Masters Projects

No abstract provided.


On The Reduction Of Genetics To Molecular Biology, Steven. O. Kimbrough Sep 1979

On The Reduction Of Genetics To Molecular Biology, Steven. O. Kimbrough

Operations, Information and Decisions Papers

The applicability of Nagel's concept of theory reduction, and related concepts of reduction, to the reduction of genetics to molecular biology is examined using the lactose operon in Escherichia coli as an example. Geneticists have produced the complete nucleotide sequence of two of the genes which compose this operon. If any example of reduction in genetics should fit Nagel's analysis, the lactose operon should. Nevertheless, Nagel's formal conditions of theory reduction are inapplicable in this case. Instead, it is argued that genetics has been partially reduced to molecular biology in the sense of token-token reduction.


Detection Of Unique Tumor-Associated Proteins In The Urine Of Patients With Transitional Cell Carcinoma By High Resolution Two-Dimensional Polyacrylamide Gel Electrophoresis, Robert David Lehman Jul 1979

Detection Of Unique Tumor-Associated Proteins In The Urine Of Patients With Transitional Cell Carcinoma By High Resolution Two-Dimensional Polyacrylamide Gel Electrophoresis, Robert David Lehman

Biological Sciences Theses & Dissertations

A two-dimensional polyacrylamide gel electrophoretic technique was developed for the detection of unique tumor-associated proteins in urine of patients with transitional cell carcinoma (TCC) of the urinary bladder. This technique yielded high resolution of polypeptides in the urine of cancer patients. Urine was chosen as a source of tumor-associated components because the location of the tum or should release already solublized tum or substances in to the urine.

Urinary proteins were concentrated and then analyzed by the two - dimensional electrophoretic technique using isoelectric focusing in the first dimension and sodium dodecylsulfate - polyacrylamide gel electrophoresis in the second dimension. Ten transitional ...


Time Course Of Pr Of Uv-Induced Chromosomal Aberrations And Lethal Damage In S And G2 Xenopus Cells, Jan Payne, H. Gaston Griggs Jan 1979

Time Course Of Pr Of Uv-Induced Chromosomal Aberrations And Lethal Damage In S And G2 Xenopus Cells, Jan Payne, H. Gaston Griggs

Journal of the Arkansas Academy of Science

Sand G2 phase cells were exposed to 150 ergs mm⁻² UV and their ability to photoreactivate the induced cell killing (loss of colony forming ability) and chromosomal aberrations was determined as a function of time following the UV exposure. In S phase cells, the lesions leading to cell death and those leading to aberrations were both converted to a non-photoreactivable state shortly after the UV exposure. A significant fraction of the lesions induced in G2 cells, that led to cell death, were converted to a non-photoreactivable state before the progeny of the exposed cells reached the next succeeding S ...


Sperm-Egg Interactions In The Horseshoe Crab, Limulus Polyphemus L.: 1) Roles Of Ions And Egg Factors In Sperm Motility And Acrosome Reaction Initiation, And 2) Light- And Scanning Electron-Microscopical Examination Of The Egg Cortical Interaction, David Lee Clapper Jan 1979

Sperm-Egg Interactions In The Horseshoe Crab, Limulus Polyphemus L.: 1) Roles Of Ions And Egg Factors In Sperm Motility And Acrosome Reaction Initiation, And 2) Light- And Scanning Electron-Microscopical Examination Of The Egg Cortical Interaction, David Lee Clapper

Retrospective Theses and Dissertations

No abstract provided.


Cell Phases During Endoreduplication Induced By Colcemid Or Radiation In Cultured Human Lymphocytes, Kenneth Eugene Weber Jan 1979

Cell Phases During Endoreduplication Induced By Colcemid Or Radiation In Cultured Human Lymphocytes, Kenneth Eugene Weber

Dissertations, Theses, and Masters Projects

No abstract provided.


The Effect Of Parental Bone Marrow & Spleen Cells In The Induction Of The Graft-Versus-Host Reaction, Ronald Grane Aug 1978

The Effect Of Parental Bone Marrow & Spleen Cells In The Induction Of The Graft-Versus-Host Reaction, Ronald Grane

Masters Theses & Specialist Projects

Variously aged (C57BL X C3H)F1 hybrid mice were used as recipients in experiments to determine if spleen or bone marrow cells from normal C57BL or C3H donors, spleen or bone marrow cells from C57BL donors previously treated with cortisone, or C57BL bone marrow cells previously incubated with serum from X-irradiated C57BL mice could induce a graft-versus-host reaction (GVHR).

The mice were assayed for GVHR by mortality or splenomegaly as detected by the discriminant spleen assay developed by Simonsen. Results show that spleen cells from normal C57BL, normal C3H, or cortisone-treated C57BL mice are capable of inducing a GVHR ...


Anionic Transport In Nitella Clavata, Bonnie L. Bower Jul 1978

Anionic Transport In Nitella Clavata, Bonnie L. Bower

Biology Master’s Theses

This study examines aspects of anion transport, focusing on Cl-, No3- and So4-2 in Nitella clavata. The researcher measures the uptake of radioactive Cl- in the presence/absence of a hexose in order to determine if glucose inhibits Cl- influx. The author grew Nitella clavata in open tanks of culture solution, with a light intensity of 100 foot-candles at the cultures’ surface. Only the first, second, or third intermodal cells proximal to the apical tip were used. Harvested cells were then conditioned from one to seven days under controlled conditions. First, the researcher used titration to measure ...


Synthesis Of Histone Messenger Rnas By Rna Polymerase Ii In Nuclei From S Phase Hela S3 Cells, Siegfried Detke, Janet L. Stein, Gary S. Stein May 1978

Synthesis Of Histone Messenger Rnas By Rna Polymerase Ii In Nuclei From S Phase Hela S3 Cells, Siegfried Detke, Janet L. Stein, Gary S. Stein

Stein, Stein, Lian, vanWijnen Lab Publications

Nuclei were isolated from synchronized HeLa S3 cells and transcribed utilizing their endogenous RNA polymerases. Our data suggest that S phase nuclei are capable of synthesizing histone mRNA sequences while nuclei from G1 phase cells are not. Transcription of histone mRNA sequences by S phase nuclei can be abolished completely by low levels of alpha-amanitin (1.0 microgram/ml, a concentration which completely inhibits RNA polymerase II). From these results it appears that transcription of the histone mRNA sequences occurs during the S phase but not during the G1 phase of the cell cycle and that RNA polymerase II is ...


A Study Of Radiation-Induced Heritable Damage (Small-Colony-Formation) In Chinese Hamster Cells, Sam Tacke Apr 1978

A Study Of Radiation-Induced Heritable Damage (Small-Colony-Formation) In Chinese Hamster Cells, Sam Tacke

Life and Environmental Sciences Undergraduate Theses

Seventeen small-colony-forming sublines of V79-AL885D were isolated and their radiosensitivities assayed. It was found that most sublines were more sensitive to UV and X-ray irradiation and more resistant to near-UV irradiation than the parental line. No correlation was found between ouabain resistance and small-colony-formation. An attempt was made to adapt the tetrazolium salt assay for respiration deficiency in yeasts to mammalian cell systems. Although color developed over most colonies, the ability of the test to reflect metabolic rates in V79 Chinese hamster cells was not conclusively demonstrated.


Dose-Response Relationships Of Triethylenemelamine On Visible Chromosome Aberrations In Mouse Bone Marrow, John Watkins, Nick Thennis Apr 1978

Dose-Response Relationships Of Triethylenemelamine On Visible Chromosome Aberrations In Mouse Bone Marrow, John Watkins, Nick Thennis

Life and Environmental Sciences Undergraduate Theses

Cytogenetic analysis of mouse bone marrow chromosomes after treatment of the experimental animals with triethylenemelamine (TEM) revealed, an overall increase in the number of chromosome aberrations A dose-response curve for TEM is given and its significance discussed. An unexpected increase in the number of rings as well as a relatively constant value for the aberrations/oell ratio in each of three dosage groups (and control) were observed. Possible mechanisms are given attention.


Analysis Of The Flagellar Membrane Proteins Of Chlamydomonas Moewusii, Cheryl Lynn Jamieson Jan 1978

Analysis Of The Flagellar Membrane Proteins Of Chlamydomonas Moewusii, Cheryl Lynn Jamieson

Biology Master’s Theses

This investigation was concerned with the analysis of the proteins isolated from the gamone (flagellar membrane vesicles isolated from the medium) of Chlamydomonas moewusii. SDS-polyacrylamide gel electrophoresis of gamone isolated from (+) and (-) cell types indicated possible differences between vegetative and gametic gamone within mating types and a degree of similarity within vegetative and gametic gamone of both mating types. Electrophoretic analysis of several molecular weight standards indicated that the major proteins from all gamone types are glycoproteins of relatively high molecular weight (100-150, 000 D.) Con A affinity chromatography of membranes solubilized in 1% DOC in 10 mM Tris, pH ...


Chlamydomonas Moewusii Pairing: Optimal Conditions And Drug Effects, Thomas Michael Lembo Jan 1978

Chlamydomonas Moewusii Pairing: Optimal Conditions And Drug Effects, Thomas Michael Lembo

Biology Master’s Theses

The effect of various mating conditions on the pairing percentages in Chlamydomonas moewusii were determined. A pairing percentage of 43% was obtained when gametes induced at 21°c were shifted to a mating temperature of 19°c for 1 hour. The lowest pairing percentage was obtained when cells were induced at 30°c and shifted to 19°c for 1 hour. The anti-microtubule agent colchicine and the anti-microfilament agent cytochalasin B were employed to determine their effect on pairing in C. moewusii. Both drugs demonstrated an inhibitory effect on pairing in Chlamydomonas. The inhibition of gametic pairing in cells treated ...


The Ultrastructure Of Cell Division In Male Reproductive Branches Of Polysiphonia Denudata, Cynthia Louise Bosco Jan 1978

The Ultrastructure Of Cell Division In Male Reproductive Branches Of Polysiphonia Denudata, Cynthia Louise Bosco

Dissertations, Theses, and Masters Projects

No abstract provided.


The Development And Assay Of An S-Phase Synchronized Cell System Using Skin Fibroblast Cultures Of The Indian Muntjac, Robert A. Cascino Dec 1977

The Development And Assay Of An S-Phase Synchronized Cell System Using Skin Fibroblast Cultures Of The Indian Muntjac, Robert A. Cascino

Biology Master’s Theses

An in vitro mammalian cell system which enables direct observation of DNA replication forks is essential to the study and understanding of the mammalian cell cycle S-phase. The prerequisite work of establishing S-phase synchronized cell cultures and an assessment of synchrony levels attained is the object of this study. Skin fibroblasts of the male Indian muntjac line which possesses large chromosomes and a low diploid number were selected for this work.

Initial block-release experiments using mitosis as an assay point indicated that 1.5 mM hydroxyurea provided marked levels of synchrony in the absence of detectable cytotoxicity. Premature chromosome condensation ...


Premature Chromosome Condensation Of Synchronized Chinese Hamster Lung Cells, Steven Michael Tucci Jun 1977

Premature Chromosome Condensation Of Synchronized Chinese Hamster Lung Cells, Steven Michael Tucci

Biology Master’s Theses

The orderly, nonrandom pattern of nuclear chromatin is observable when it is condensed as visually distinct and structurally reproducible metaphase chromosomes. Interphase nuclei are susceptible to being induced to condense prematurely when by somatic cell fusion they become exposed to the influence of mitotic nuclei. The mitotic inducer has a differential effect on G1, S, and G­2 chromatin and produces varied premature condensation products. In the following experiments metaphase-G1 fusions yielded single, elongated chromatids. The metaphase-S fusions resulted in pulverized condensation products. Metaphase-G2 fusions produced sister, elongated chromatids.

Sendai virus was used as the fusing agent ...


The Effect Of Cv-1 Cell Geometry On The Ultraviolet Radiation Sensitivity Of Mammalian Cells In Vitro, Daniel J. Knauer Jun 1977

The Effect Of Cv-1 Cell Geometry On The Ultraviolet Radiation Sensitivity Of Mammalian Cells In Vitro, Daniel J. Knauer

Masters Theses & Specialist Projects

The effect of cell geometry on the radiosensitivity to ultraviolet (UV) light has been studied in the CV-1 host cell-capacity system. In this system the macromolecular damage incurred by monolayers of cells cultures as the result of exposure to UV radiation is monitored by testing the ability of irradiated cells to support the replication of Herpes simplex virus. The target molecule has been shown to be DNA and is centrally located

Mammalian cells have an absolute requirement for Mg++ and Ca++ in order to remain attached to artificial substrata. To test the effect of cell geometry on UV radiation sensitivity ...