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1992

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Articles 1 - 22 of 22

Full-Text Articles in Cell Biology

Poly(A) Rna Codistribution With Microfilaments: Evaluation By In Situ Hybridization And Quantitative Digital Imaging Microscopy, Krishan L. Taneja, Lawrence M. Lifshitz, Fredric S. Fay, Robert H. Singer Dec 1992

Poly(A) Rna Codistribution With Microfilaments: Evaluation By In Situ Hybridization And Quantitative Digital Imaging Microscopy, Krishan L. Taneja, Lawrence M. Lifshitz, Fredric S. Fay, Robert H. Singer

Open Access Articles

The distribution of poly(A) RNA has been visualized in single cells using high-resolution fluorescent in situ hybridization. Digital imaging microscopy was used to quantitate the signal in various cellular compartments. Most of the poly(A) signal remained associated with the cellular filament systems after solubilization of membranes with Triton, dissociation of ribosomes with puromycin, and digestion of non-poly(A) RNA with ribonuclease A and T1. The actin filaments were shown to be the predominant cellular structural elements associating with the poly(A) because low doses of cytochalasin released about two-thirds of the poly(A). An approach to assess the ...


Predicting The Growth Of Salmonella Typhimurium On Beef By Using The Temperature Function Integration Technique, James S. Dickson, G. R. Siragusa, J. E. Wray Jr. Nov 1992

Predicting The Growth Of Salmonella Typhimurium On Beef By Using The Temperature Function Integration Technique, James S. Dickson, G. R. Siragusa, J. E. Wray Jr.

James S. Dickson

Lag and generation times for the growth of Salmonella typhimurium on sterile lean beef were modeled as functions of cooling time under various carcass-chilling scenarios. Gompertz growth models were fit to the log10 colony counts over time at each of six temperatures in the range of 15 to 40 degrees C. Lag and generation times were defined as the points at which the second and first derivatives, respectively, of each growth curve attained a maximum. Generation time and lag time parameters were modeled as functions of temperature by use of exponential-decay models. The models were applied to typical beef carcass-cooling ...


Changes In Intracellular Chloride During Osmotic Stress And L-Alanine Uptake In Mouse Hepatocytes, Kening Wang Oct 1992

Changes In Intracellular Chloride During Osmotic Stress And L-Alanine Uptake In Mouse Hepatocytes, Kening Wang

Electronic Theses and Dissertations

A stable intracellular ionic environment is necessary for hepatocytes to function normally. Thus, during hypotonic shock or L-alanine uptake, hepatocytes swell and then exhibit a regulatory volume decrease (RVD), which comprises an increase in K$\sp+$ conductance (G$\sb{\rm K}$), an increased K$\sp+$ efflux, and a hyperpolarization of transmembrane potential (V$\sb{\rm m}$). Since hepatocyte intracellular Cl$\sp-$ has been demonstrated to distribute passively with V$\sb{\rm m}$, this study is designed to test the hypothesis that the hypotonic shock- or L-alanine uptake-induced hyperpolarization of V$\sb{\rm m}$ might provide an electromotive force for the ...


Die Konsequenzen Eines Lebens Im Druckbehälter. Biotheoretische Implikationen Der Organisation Pflanzlicher Organismen [The Consequences Of Living In A Pressure Pot. Biotheoretical Implications Of The Organismic Architecture Of Plants], Winfried Peters, Hubert Felle Jun 1992

Die Konsequenzen Eines Lebens Im Druckbehälter. Biotheoretische Implikationen Der Organisation Pflanzlicher Organismen [The Consequences Of Living In A Pressure Pot. Biotheoretical Implications Of The Organismic Architecture Of Plants], Winfried Peters, Hubert Felle

Winfried S. Peters

Die Betrachtung der sich aus der zellulären Osmo- und Druckregulation ergebenden konstruktiven Zwänge erlaubt es, invariante Eigenschaften makroskopischer Pflanzen abzuleiten. Sessilität wird als grundsätzlich unumgänglich erkannt; Autotrophie als zwangsläufige Ernährungsform kann nur durch Parasitismus oder Beteiligung an Symbiosen umgangen werden. Hieraus ergibt sich die Antwort auf die Frage nach dem “Unterschied” zwischen Tieren und Pflanzen: die Bildung clonarer Kolonien (Metapopulationen) kann bei sessilen Organismen besonders plausibel begründet werden, zumal, wenn diese autotroph leben. Sessilität stellt bei Tieren eine Option, bei makroskopischen Pflanzen aber eine Notwendigkeit dar. Das Vorherrschen des Konstruktionstyps “Metapopulation” bei Pflanzen ist damit vorgezeichnet; dies ist letztlich eine ...


The Role And Fate Of Dna Ends For Homologous Recombination In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Allan Bradley Jun 1992

The Role And Fate Of Dna Ends For Homologous Recombination In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Allan Bradley

Rivera Lab Publications

We have analyzed the gene-targeting frequencies and recombination products generated by a series of vectors which target the hprt locus in embryonic stem cells and found the existence of alternative pathways that depend on the location of the double-strand break within the vector. A double-strand break in the targeting homology was found to increase the targeting frequency compared with a double-strand break at the edge of or outside the target homology; this finding agrees with the double-strand break repair model proposed for Saccharomyces cerevisiae. Although a double-strand break in the homology is important for efficient targeting, observations reported here suggest ...


Molecular And Cellular Analysis Of Chlamydia Trachomatis: Persistence And Reactivation, Kimberly R. Tau May 1992

Molecular And Cellular Analysis Of Chlamydia Trachomatis: Persistence And Reactivation, Kimberly R. Tau

Electronic Theses and Dissertations

Chlamydia trachomatis (CT) is the most prevalent sexually-transmitted infection in the United States. It has been suggested that CT infections can become latent. This has not been substantiated. CT persistence was examined at the molecular and cellular level in vitro and in vivo. Penicillin treatment of CT in vitro results in abnormal inclusions and reduced recovery of infectious CT. Penicillin did not inhibit initial stages of infection, but did downregulate CT rRNA levels after 25 hours post-inoculation (p.i.). DNA amplification was employed to differentiate between a resolved infection and a persistent one. Utilizing a primer pair that amplified a ...


Protein Translocation Across The Er Requires A Functional Gtp Binding Site In The Alpha Subunit Of The Signal Recognition Particle Receptor, Peter J. Rapiejko, Reid Gilmore May 1992

Protein Translocation Across The Er Requires A Functional Gtp Binding Site In The Alpha Subunit Of The Signal Recognition Particle Receptor, Peter J. Rapiejko, Reid Gilmore

Open Access Articles

The signal recognition particle (SRP)-mediated translocation of proteins across the RER is a GTP dependent process. Analysis of the primary amino acid sequence of one protein subunit of SRP (SRP54), as well as the alpha subunit of the SRP receptor (SR alpha), has indicated that these proteins contain predicted GTP binding sites. Several point mutations confined to the GTP binding consensus elements of SR alpha were constructed by site specific mutagenesis to define a role for the GTP binding site in SR alpha during protein translocation. The SR alpha mutants were analyzed using an in vitro system wherein SR ...


The Effect Of Retinoic Acid On Normal Human Foreskin Epithelial Cells And Hpv-Immortalized Cells Grown In Organotypic Raft Cultures, Kristin Whittenburg Apr 1992

The Effect Of Retinoic Acid On Normal Human Foreskin Epithelial Cells And Hpv-Immortalized Cells Grown In Organotypic Raft Cultures, Kristin Whittenburg

Life and Environmental Sciences Undergraduate Theses

Previous studies have shown that epithelial cells immortalized by human papillomaviruses (HPVs) at late passages were more resistant to the effects of retinoic acid than late passage normal keratinocytes. Some of these late passage HPV-immortalized cells, however, lose the ability to form a cornified envelope with continued culturing. For this reason, early passage normal keratinocytes and early passage HPV-immortalized cells were studied to see if they also showed this resistance to retinoic acid. Normal epithelial cells and cells immortalized by HPVs were grown in organotypic raft cultures and treated with varying amounts of retinoic acid, which normally blocks terminal differentiation ...


In Vitro Study Of The Effect Of Hypothermia On The Dissociation Curve Of Blood, Matthew Munding Apr 1992

In Vitro Study Of The Effect Of Hypothermia On The Dissociation Curve Of Blood, Matthew Munding

Life and Environmental Sciences Undergraduate Theses

The aim of this study was to examine the change in the dissociation curve of oxygen from human hemoglobin at the temperatures of 37°, 25°, 18°, 12°, 7°, and 3° C. The partial pressures of oxygen and the calculated hemoglobin saturations were determined for samples at the various temperatures. From this data the partial pressures at 75% saturation were calculated, and the differences in the partial pressures at 75% saturation were compared. The dissociation curve was shown to shift to the left as the temperature was decreased down to 12°. Below 12°, the shift was not further observed. At the ...


Characterization Of A Novel Prostate Tumor-Associated Antigen, Grayson B. Lipford Apr 1992

Characterization Of A Novel Prostate Tumor-Associated Antigen, Grayson B. Lipford

Theses and Dissertations in Biomedical Sciences

The murine monoclonal antibodies (MAb) TURP-27 and HNK-1 have been shown to detect antigens that are heavily expressed by benign prostatic hyperplasia (BPH) and carcinoma of the prostate (CaP). Western blot analysis of prostate extracts, showed that MAb TURP-27 and MAb HNK-1 bound glycoproteins of 180, 140, 120, 100, 90 and 69 kDa. Studies have shown that the HNK-1 carbohydrate epitope may be involved in cell adhesion and that it is a component of several characterized adhesion proteins. TURP-27 was found to bind at least three of these adhesion proteins: neural cell adhesion molecules (N-CAM), myelin-associated glycoprotein (MAG) and a ...


Prevention Of Diabetes In Bb/Wor Rats By Intrathymic Islet Injection, Steven B. Koevary, Maureen Blomberg Feb 1992

Prevention Of Diabetes In Bb/Wor Rats By Intrathymic Islet Injection, Steven B. Koevary, Maureen Blomberg

Open Access Articles

The objective of this study was to determine whether the intrathymic injection of islets can prevent the development of diabetes in BB/Wor rats. Evidence suggests that a failure to induce islet thymic tolerance may be an etiological factor in the development of the disease. It was theorized that the introduction of islets into the thymus might directly induce islet tolerance and thus prevent disease. Islets from diabetes-resistant BB/Wor rats were injected into the thymuses of 23 young diabetes-prone BB/Wor rats; 25 sham-operated animals served as controls. Results showed that 22 of the 25 control rats became diabetic ...


The Cγ Subunit Is A Unique Isozyme Of The Camp-Dependent Protein Kinase, Stephen J. Beebe, Paul Salomonsky, Tore Jahnsen, Yixin Li Jan 1992

The Cγ Subunit Is A Unique Isozyme Of The Camp-Dependent Protein Kinase, Stephen J. Beebe, Paul Salomonsky, Tore Jahnsen, Yixin Li

Bioelectrics Publications

There are at least three isozymes (Cα, Cβ, and Cγ) of the mammalian catalytic (C) subunit of cAMP-dependent protein kinase (PKA) (Beebe, S., Oyen, O., Sandberg, M., Froysa, A., Hansson, V., and Jahnsen, T. (1990) Mol. Endocrinol. 4, 465-475). To compare the Cγ and Cα isozymes, the respective cDNAs were expressed in permanently transformed Kin-8 PKA-deficient Y1 adrenal cells using the mouse metallothionein promoter. The recombinant C subunits were characterized as immunoreactive, zinc-inducible, cAMP-dependent kinase activities. In contrast to Cα, histone was a better substrate than Leu-Arg-Arg-Ala-Ser-Leu-Gly (Kemptide) for Cγ. Furthermore, Cγ histone kinase activity was not inhibited by the ...


Genetic And Biochemical Characterization Of The P21[Superscript Ras]-Related Protein Rho1p In The Yeast Saccharomyces Cerevisiae , Joni Marie Seeling Johnson Jan 1992

Genetic And Biochemical Characterization Of The P21[Superscript Ras]-Related Protein Rho1p In The Yeast Saccharomyces Cerevisiae , Joni Marie Seeling Johnson

Retrospective Theses and Dissertations

Rho1p is a guanine nucleotide binding protein coded for by the Saccharomyces cerevisiae gene RHO1, which is homologous to p21[superscript] ras and other members of the ras superfamily of small molecular weight GTP binding proteins. This protein family is highly conserved in evolution and in some instances is known to be involved in control of cell proliferation. The precise physiological functions of most p21[superscript] ras-related proteins, however, are not known. In order to gain further insight into the physiological function of rho proteins, this research addressed the genetic and biochemical characterization of Rho1p, as well as the subcellular ...


The Characterization And Purification Of Matrixin-A, A Plasmin Releasable Growth Inhibitor Associated With The Extracellular Matrix , Scott William Miller Jan 1992

The Characterization And Purification Of Matrixin-A, A Plasmin Releasable Growth Inhibitor Associated With The Extracellular Matrix , Scott William Miller

Retrospective Theses and Dissertations

The aim of this project is to examine the role of proteases and protease inhibitors in the regulation of cell proliferation. It also describes a simple, high yield purification of bovine platelet derived TGF-[beta] that uses a novel bioassay to specifically identify TGF-[beta] mediated activity;The composition of the extracellular matrix (ECM) is an important determinant of the rate cellular proliferation and differentiation. Growth factors and other proteins with growth regulatory activities can affect the composition of the ECM. Growth regulators are also associated with the ECM and can be released by the action of ECM associated proteolysis ...


Characterization Of The Saccharomyces Cerevisiae Gene Mgp1, A Novel Member Of The Ras Gene Superfamily That Functions In The Mitochondrial Biogenesis , Shu-Hwa Lee Tzeng Jan 1992

Characterization Of The Saccharomyces Cerevisiae Gene Mgp1, A Novel Member Of The Ras Gene Superfamily That Functions In The Mitochondrial Biogenesis , Shu-Hwa Lee Tzeng

Retrospective Theses and Dissertations

This dissertation characterizes Mgp1p, a mitochondrial protein that functions in mitochondrial biogenesis. Mgp1p is the first protein related to the p21[superscript] H-ras oncoprotein shown to function in mitochondria;The Saccharomyces cerevisiae gene MGP1 was isolated based on its ability to restore respiratory competence to a strain containing the nuclear petite mutation msg1-1. MGP1 codes for a protein of approximately 58 kDa, with an amino terminal sequence typical of a mitochondrial targeting peptide. A 190 residue region of Mgp1p shares approximately 30% amino acid sequence identity with any member of p21[superscript] ras-related protein superfamily, with particularly strong homology in ...


Development And Regulation Of Estrogen Receptors In The Neonatal Rat Hippocampus, Joan A. O'Keefe Jan 1992

Development And Regulation Of Estrogen Receptors In The Neonatal Rat Hippocampus, Joan A. O'Keefe

Dissertations

No abstract provided.


Amino Acids And Pineal Gland Function In The Rat, Laura Kus Jan 1992

Amino Acids And Pineal Gland Function In The Rat, Laura Kus

Dissertations

No abstract provided.


Magnesium Regulation Of Calcium In Essential Hypertension, Elaine Pringle Gordon Jan 1992

Magnesium Regulation Of Calcium In Essential Hypertension, Elaine Pringle Gordon

Theses and Dissertations in Biomedical Sciences

Essential hypertension is a complex disease which is treated by palliative methods, since the causal factors are as yet unknown. A variety of both genetic and environmental factors probably combine to produce chronic high blood pressure. A genetic model of essential hypertension, spontaneously hypertensive rats (SHR), and its control strain Wistar Kyoto (WKY) were used to investigate a possible environmental causal factor, cellular magnesium deficit, and its impact on the functional ability of the calcium ATPase. Rats were fed either a magnesium-deficient or a magnesium-sufficient diet for 10 weeks, after which the calcium ATPase activity was measured in intact red ...


Cloning And Characterization Of Mink Plasminogen Activator Inhibitor Type 1 (Pai-1) Cdna And The Regulation Of Mink Pai-1 Expression At Mrna Level , Tsung-Hsien Chuang Jan 1992

Cloning And Characterization Of Mink Plasminogen Activator Inhibitor Type 1 (Pai-1) Cdna And The Regulation Of Mink Pai-1 Expression At Mrna Level , Tsung-Hsien Chuang

Retrospective Theses and Dissertations

Mink plasminogen activator inhibitor type 1 (PAI-1) is a glycoprotein with molecular weight about 50 kD and is highly regulated in cultured cells. In mink lung CCL64 epithelial cells, epidermal growth factor (EGF), transforming growth factor-[beta] (TGF-[beta]), and 12-O-tetradecanoyl phorbol-13-acetate (TPA) increase the synthesis of PAI-1. Epidermal growth factor and TGF-[beta] synergistically stimulate the synthesis of PAI-1. The synergistic effect and factors which govern the PAI-1 expression in mink lung CCL64 cells were studied by using a mink PAI-1 cDNA as a probe to detect PAI-1 mRNA;The mink PAI-1 cDNA was cloned from a cDNA library ...


Direct Introduction Of Dna Into Embryonic Axes Of Glycine Max By Microprojectile Bombardment , Charisse Marie Buising Jan 1992

Direct Introduction Of Dna Into Embryonic Axes Of Glycine Max By Microprojectile Bombardment , Charisse Marie Buising

Retrospective Theses and Dissertations

Apical meristem and axillary bud development in germinating soybean embryonic axes treated for 24 hr with the cytokinin, 6-benzylaminopurine (BAP) seemed normal morphologically, but was delayed by about 9 to 15 hr. After 5 days, numerous, rapidly proliferating meristematic regions (de novo vegetative buds) were observed in BAP-treated axes around the perimeter of the apical dome. These visible changes were preceded by transient inhibition of DNA synthesis in the shoot apices as early as 21-36 hr post-imbibition;Some of the new meristematic regions developed into multiple shoots, which were excised, subcultured, and used to generate mature plants. In the absence ...


Biochemical Composition Of The Spermatozoal Plasma Membrane In Normal And Heat-Stressed Boars , Gary Carl Althouse Jan 1992

Biochemical Composition Of The Spermatozoal Plasma Membrane In Normal And Heat-Stressed Boars , Gary Carl Althouse

Retrospective Theses and Dissertations

The biochemical composition of ejaculated spermatozoal plasma membranes from normal-control (n = 4) and heat-stressed (n = 4) paired, sibling boars was assessed over a 9-week collection period. A total of 36 ejaculates were collected from the normal-control boars. Phospholipids (PL) accounted for 83.5% of the membrane lipid material, with sterols making up the remaining 16.5%. Phosphatidylcholine was the most abundant PL (56.6%), followed by sphingomyelin (16.6%), phosphatidylglycerides (11.0%), lysophosphatidylcholine (9.0%), phosphatidylethanolamine (5.8%), and phosphatidylinositol (1.0%). Cholesterol was the major sterol found in the sperm's plasma membrane (72.1%), with desmosterol being the ...


Auxin-Induced H+-Pump Stimulation Does Not Depend On The Presence Of Epidermal Cells In Corn Coleoptiles, Winfried Peters, Ursula Richter, Hubert Felle Dec 1991

Auxin-Induced H+-Pump Stimulation Does Not Depend On The Presence Of Epidermal Cells In Corn Coleoptiles, Winfried Peters, Ursula Richter, Hubert Felle

Winfried S. Peters

Cell-wall acidification and electrical reactions (depolarization and hyperpolarization) are typical auxin responses in maize (Zea mays L.) coleoptiles. In an attempt to test the role of the outer epidermis in these responses, they have been measured and compared in intact and peeled coleoptile fragments. To exclude interactions between parenchymal and epidermal cells, the coleoptile pieces were completely stripped of their outer epidermis. This preparation was monitored by means of a scanning electron microscope. When externally applied indole-3-acetic acid was tested, we found that neither cell-wall acidification nor the electrical membrane responses depended on the presence of intact epidermal cells.