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Full-Text Articles in Cell Biology

Ultra-Structural Identification Of The Interstitial Cells Of Cajal In The Zebrafish Danio Rerio, Evan R. Ball, Miho M. Matsuda, Louis Dye, Victoria Hoffmann, Patricia M. Zerfas, Eva Szarek, Adam Rich, Ajay Chitnis, Constantine A. Stratakis Jan 2012

Ultra-Structural Identification Of The Interstitial Cells Of Cajal In The Zebrafish Danio Rerio, Evan R. Ball, Miho M. Matsuda, Louis Dye, Victoria Hoffmann, Patricia M. Zerfas, Eva Szarek, Adam Rich, Ajay Chitnis, Constantine A. Stratakis

Biology Faculty Publications

The interstitial cells of Cajal (ICCs) are important mediators of gastrointestinal motility due to their role as pacemakers in the GI tract. In addition to their function, ICCs are also structurally distinct cells most easily identified by their ultra-structural features and expression of the tyrosine kinase receptor c-KIT. ICCs have been described in mammals, rodents, birds, reptiles and amphibians ; there are no reports at the ultra-structural level of ICC’s within the GI tract of an organism from the teleost lineage. This report describes the presence of cells in the muscularis of the zebrafish intestine with similar features to ICCs ...


The Role Of The Mrx Complex And The Non-Homologous End Joining Dna Repair Pathway In Mitochondrial Genome Stability And Repair, Garry L. Coles Aug 2009

The Role Of The Mrx Complex And The Non-Homologous End Joining Dna Repair Pathway In Mitochondrial Genome Stability And Repair, Garry L. Coles

Biology Master’s Theses

Mitochondria are required for cellular respiration, which is essential in the production of ATP. Mitochondrial genome maintenance is necessary for the continued function of the mitochondrion. Deletions within the mitochondrial DNA (mtDNA) have been shown to be associated with a variety of human neuromuscular and age-related diseases. In this study we investigated the role of the MRX complex and the non-homologous end joining (NHEJ) DNA repair pathway in mitochondrial genome stability and repair. Specifically, we investigated the role of the MRX complex and the NHEJ pathway in the occurrence of spontaneous mitochondrial direct repeat-mediated deletions, nuclear direct repeat-mediated deletions, mitochondrial ...


The Α 1h Ca2+ Channel Subunit Is Expressed In Mouse Jejunal Interstitial Cells Of Cajal And Myocytes, Simon J. Gibbons, Peter R. Strege, Sha Lei, Jaime L. Roeder, Amelia Mazzone, Yijun Ou, Adam Rich, Gianrico Farrugia Jan 2009

The Α 1h Ca2+ Channel Subunit Is Expressed In Mouse Jejunal Interstitial Cells Of Cajal And Myocytes, Simon J. Gibbons, Peter R. Strege, Sha Lei, Jaime L. Roeder, Amelia Mazzone, Yijun Ou, Adam Rich, Gianrico Farrugia

Biology Faculty Publications

T-type Ca2+ currents have been detected in cells from the external muscular layers of gastrointestinal smooth muscles and appear to contribute to the generation of pacemaker potentials in interstitial cells of Cajal from those tissues. However, the Ca2+ channel subunit responsible for these currents has not been determined. We established that the α subunit of the α1H Ca2+ channel is expressed in single myocytes and interstitial cells of Cajal using reverse transcription and polymerase chain reaction from whole tissue, laser capture microdissected tissue and single cells isolated from the mouse jejunum. Whole-cell voltage clamp recordings demonstrated ...


The Role Of Ilv5p Interacting Factors In Mitochondrial Dna Stability, Anthony J. Mirando Jun 2006

The Role Of Ilv5p Interacting Factors In Mitochondrial Dna Stability, Anthony J. Mirando

Biology Master’s Theses

The ease of manipulating yeast allows for advanced studies on the factors affecting the mitochondrial DNA mutation rates. The control mechanisms of the mitochondrial DNA mutation rate has been determined to involve the dual function protein, Ilv5p. The Ilv5p plays an integral role in the proper segregation of newly replicated mitochondrial DNA into daughter cells during cell division. The focus of this study is to find unknown factors involved in mitochondrial DNA stability. This study uses the Ilv5p to pull unknown factors out of the many genes that comprise the yeast genome. The identification of interacting factors of the Ilv5p ...


Evaluation Of Gyp7 Protein Ability To Coordinate And Regulate Mitochondrial Genomes Stability, Louis Didone Jun 2006

Evaluation Of Gyp7 Protein Ability To Coordinate And Regulate Mitochondrial Genomes Stability, Louis Didone

Biology Master’s Theses

Cellular creation of adenosine triphosphate, ATP, is essential for eukaryotic cells to function properly. The ATP molecule drives most of the biochemical and metabolic pathways of the cell. The cell's ATP is produced in the mitochondria. Mutations within the genome of the mitochondria will alter the cell's ability to generate A TP. Preliminary work has shown that loss of the Gyp 7p in Saccharomyces cerevisiae blocks the ability of mitochondria to properly function. The Gyp 7 gene was isolated using a technique called two-hybrid analysis with a known mitochondrial protein called llvSp, which was used as 'bait'. We ...


3’ Terminal Processing Of Precursor Trna Transcribed From A Drosophila Melanogaster Histidine Gene In A Cell-Free System, James P. Fulginiti Jan 1987

3’ Terminal Processing Of Precursor Trna Transcribed From A Drosophila Melanogaster Histidine Gene In A Cell-Free System, James P. Fulginiti

Biology Master’s Theses

Transfer RNA biosynthesis is a complex process which includes trimmings at the 5' and 3' termini and nucleotide modification of the initial tRNA precursor. This research involves the detention and isolation of a 3' endonucleolytic activity from Schizosaccharomyces pombe.

tRNA precursors are obtained from a cell-free transcription system using (i) a Drosophila tRNA-histidine gene which contains a 35 base pair trailer sequence at its 3' terminus and (ii) a crude yeast enzyme extract which can faithfully transcribe the gene and process the precursor transcripts. Transcription products are separated by means of polyacryfamide gel electrophoresis visualized by autoradiography, and eluted from ...


Development Of A Yeast Transcription System Using A Saccharomyces Cerevisiae Enzyme Extract And A Drosophila Melanogaster Histidine Trna Gene, Diana M. Parker Dec 1985

Development Of A Yeast Transcription System Using A Saccharomyces Cerevisiae Enzyme Extract And A Drosophila Melanogaster Histidine Trna Gene, Diana M. Parker

Biology Master’s Theses

This research problem is directed toward the isolation of an enzyme from the yeast Saccharomyces pombe which endonucleolytically processes the 3' terminus of transfer ribonucleic acids.

Plasmids containing tRNA genes were a gift from Dieter Soll, Yale University Department of Molecular Biophysics and Biochemistry. In order to provide increasing amounts of the cloned gene, the bacterium Escherichia coli HB101 was transformed using standard transformation procedures and methods.

The transformed bacteria were cultured, and the plasmids amplified using chloramphenicol. These bacteria were then lysed and cesium chloride-ethidium bromide gradients were run to isolate plasmids containing the desired genes.

The plasmids were ...


W-Reactivation (Inducible "Sos" Dna Repair) Of Double Stranded Dna Bacteriophage Λ And Single Stranded Dna Bacteriophage Fd On Isogenic Rec And Uvrb Mutants Of Escherichia Coli K-12, Sammy F.W. Ndive May 1983

W-Reactivation (Inducible "Sos" Dna Repair) Of Double Stranded Dna Bacteriophage Λ And Single Stranded Dna Bacteriophage Fd On Isogenic Rec And Uvrb Mutants Of Escherichia Coli K-12, Sammy F.W. Ndive

Biology Master’s Theses

The recA mutant has been shown to be completely recombination deficient and highly UV-sensitive. Also, this mutant is remarkably deficient in inducible "SOS" DNA repair and, consequently it is not UV-mutable and it cannot perform W-reactivation, an inducible non-excision repair dependent enhancement of phage recovery. The recB-recF- double mutant like the recA mutant, is recombination deficient and UV-sensitive.

As observed, each of these mutations appear to block an independent pathway of genetic recombination.

We are interested in determining how closely the recB-recF- double mutant resembles the recA mutant. In this perspective we looked at the W-reactivation of double ...


Reca-Independence Of Residual Dimer Excision In A Reci.152 Mutant Of Esherichia C01.1 K-12, Barry Fried Jun 1982

Reca-Independence Of Residual Dimer Excision In A Reci.152 Mutant Of Esherichia C01.1 K-12, Barry Fried

Biology Master’s Theses

Wild-type strains of E. coli possess both short and long patch repair mechanisms to correct UV-induced pyrimidine dimers. Short patch repair is the predominant mode, and long patch repair is recA+ -dependent, requires de novo protein synthesis, and is UV-inducible. Excision repair in a recI.152 mutant is characterized by slow dimer excision and the exhibition of primarily large patches. Residual excision repair in the recI.152 mutant was studied by introducing a recA.56 mutation into the recI.152 strain. Analysis of cell survival, host-cell reactivation, Weigle-reactivation, and the rate of dimer release in both the recL152 single mutant ...


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 ...


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 ...


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 ...


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 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 ...


Detection Of 5-Bromodeoxyuridine Incorporation In Metaphase Chromosomes Of Dedifferentiated Melanoma Cells, David Emerson Dec 1976

Detection Of 5-Bromodeoxyuridine Incorporation In Metaphase Chromosomes Of Dedifferentiated Melanoma Cells, David Emerson

Biology Master’s Theses

Observed reversible effects, mediated by the incorporation of 5-bromodeoxyuridine (BrdUrd) into the DNA of mouse melanoma cells were; changes in culture growth pattern, altered cell morphology and suppression of melanogenecis. The incorporation of BrdUrd into the metaphase chromosomes, was traced with 1.) the Hoechst 33258 fluorescence stain and 2.) the unlabeled antibody peroxidase method. Different levels of BrdUrd incorporation, are shown to exhibit differential staining patterns on the metaphase chromosomes. The specific sites of preferential BrdUrd incorporation may provide a morphological clue to the structural and functional changes observed.


Characterization Of Transfer Rna Associated With Plasma Membranes, Vincent Joseph Mancusi Jun 1976

Characterization Of Transfer Rna Associated With Plasma Membranes, Vincent Joseph Mancusi

Biology Master’s Theses

RNA extracted from purified rat liver plasma membranes was found to contain transfer RNA. Amino acid acceptor activity was detected for arginine and lysine, a confirmation of previous reports. In addition, acceptor activity was also detected for tryptophan and proline. Isoaccepting tRNA species for lysine and arginine were chromatographed using Benzoylated DEAE-Cellulose column chromatography. No major difference was found between cytoplasmic and membrane isoaccepting species for lysine and arginine transfer RNAs.


Cell Surface Localization Of The Sialyltransferase Ectoenzyme System During The Chlamydomonas Mating Reaction, Luciano Francis Colombino Jan 1976

Cell Surface Localization Of The Sialyltransferase Ectoenzyme System During The Chlamydomonas Mating Reaction, Luciano Francis Colombino

Biology Master’s Theses

Glycosyltransferase-acceptor activity was demonstrated previously with gametes of Chlamydomonas moewusii and was shown to be enhanced during the mating reaction (McLean and Bosmann, 1975). This investigation is intended to provide some supportive data for the surface localization of sialyltransferase activity and to determine the possibility of hydrolysis of the CMP-sialic acid substrate by surface hydrolases resulting in uptake of the labelled sialic acid. The data indicate that Chlamydomonas cannot utilize sialic acid £or growth in the dark although it is taken up by the cell. Free sialic acid uptake is not enhanced during mating. An excess of free sialic acid ...