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1997

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Articles 1 - 30 of 33

Full-Text Articles in Cell Biology

The Tim54p–Tim22p Complex Mediates Insertion Of Proteins Into The Mitochondrial Inner Membrane, Oliver Kerscher, Jason Holder, Maithreyan Srinivasan, Roxanne S. Leung, Robert E. Jensen Dec 1997

The Tim54p–Tim22p Complex Mediates Insertion Of Proteins Into The Mitochondrial Inner Membrane, Oliver Kerscher, Jason Holder, Maithreyan Srinivasan, Roxanne S. Leung, Robert E. Jensen

Arts & Sciences Articles

We have identified a new protein, Tim54p, located in the yeast mitochondrial inner membrane. Tim54p is an essential import component, required for the insertion of at least two polytopic proteins into the inner membrane, but not for the translocation of precursors into the matrix. Several observations suggest that Tim54p and Tim22p are part of a protein complex in the inner membrane distinct from the previously characterized Tim23p-Tim17p complex. First, multiple copies of the TIM22 gene, but not TIM23 or TIM17, suppress the growth defect of a tim54-1 temperature-sensitive mutant. Second, Tim22p can be coprecipitated with Tim54p from detergent-solubilized mitochondria, but ...


Coupled Er To Golgi Transport Reconstituted With Purified Cytosolic Proteins, Charles Barlowe Dec 1997

Coupled Er To Golgi Transport Reconstituted With Purified Cytosolic Proteins, Charles Barlowe

Open Dartmouth: Faculty Open Access Scholarship

A cell-free vesicle fusion assay that reproduces a subreaction in transport of pro-alpha-factor from the ER to the Golgi complex has been used to fractionate yeast cytosol. Purified Sec18p, Uso1p, and LMA1 in the presence of ATP and GTP satisfies the requirement for cytosol in fusion of ER-derived vesicles with Golgi membranes. Although these purified factors are sufficient for vesicle docking and fusion, overall ER to Golgi transport in yeast semi-intact cells depends on COPII proteins (components of a membrane coat that drive vesicle budding from the ER). Thus, membrane fusion is coupled to vesicle formation in ER to Golgi ...


Altered Trafficking Of Mutant Connexin32, Suzanne M. Deschênes, Jessica L. Walcott, Tamara L. Wexler, Steven S. Scherer, Kenneth H. Fischbeck Dec 1997

Altered Trafficking Of Mutant Connexin32, Suzanne M. Deschênes, Jessica L. Walcott, Tamara L. Wexler, Steven S. Scherer, Kenneth H. Fischbeck

Biology Faculty Publications

We examined the cellular localization of nine different connexin32 (Cx32) mutants associated with X-linked Charcot–Marie–Tooth disease (CMTX) in communication-incompetent mammalian cells. Cx32 mRNA was made, but little or no protein was detected in one class of mutants. In another class of mutants, Cx32 protein was detectable in the cytoplasm and at the cell surface, where it appeared as plaques and punctate staining. Cx32 immunoreactivity in a third class of mutants was restricted to the cytoplasm, where it often colocalized with the Golgi apparatus. Our studies suggest that CMTX mutations have a predominant effect on the trafficking of Cx32 ...


Inhibition Of Axonal Growth By Brefeldin A In Hippocampal Neurons In Culture, Mark Jareb, Gary Banker Dec 1997

Inhibition Of Axonal Growth By Brefeldin A In Hippocampal Neurons In Culture, Mark Jareb, Gary Banker

Biology Faculty Publications

The outgrowth of neuronal processes involves a great increase in the surface area of the cell. The supply of membrane material necessarily must be coordinated with the demands for neurite growth. The selective growth of only one or two neurites at any given time during the development of polarity raises the possibility that the production of materials by the soma is limiting for growth (Dotti and Banker, 1987; Dotti et al., 1988; Goslin and Banker, 1990). To examine the role of the availability of membrane components during the development of polarity and axonal elongation, we treated neurons with brefeldin A ...


Effects Of Oxidized Low Density Lipoprotein On Nitric Oxide Production In Macrophages, Annong Huang Dec 1997

Effects Of Oxidized Low Density Lipoprotein On Nitric Oxide Production In Macrophages, Annong Huang

Electronic Theses and Dissertations

The effects of oxidatively modified low density lipoprotein (oxLDL) on atherogenesis may be partly mediated by alterations in nitric oxide (NO) production by macrophages. A major goal of this study was to identify the lipid components in oxLDL modulating NO production. The effect of a water soluble antioxidants (N-acetylcysteine) and lipid soluble antioxidant (alpha-tocopherol) on NO production in macrophages was also determined. A second goal was to determine if the effects of oxLDL occurred at the transcriptional level. Human LDL was oxidized using an azo-initiator 2,2$\sp\prime$-azobis (2-amidinopropane) HCI (ABAP). OxLDL markedly decreased the production of NO ...


Comparison Of Beta-Adrenoceptor Coupled Camp Production In Cultured Human Mononuclear Leukocytes And Myometrial Cells, Yu-Li Liu Dec 1997

Comparison Of Beta-Adrenoceptor Coupled Camp Production In Cultured Human Mononuclear Leukocytes And Myometrial Cells, Yu-Li Liu

Electronic Theses and Dissertations

$\beta\sb2$-Adrenoceptor ($\beta\sb2$-AR) agonists, such as terbutaline, are used as tocolytic agents in the treatment of preterm labor. $\beta$-Adrenoceptor stimulation relaxes myometrium through specific receptors coupled through Gs to adenylyl cyclase (AC) that catalyzes the conversion of ATP to cAMP. The purpose of this study was to compare $\beta$-adrenoceptors and cAMP production in cultured human leukocytes and myometrial cells, and to determine the importance of $\beta$-adrenoceptors and cAMP production in isoproterenol-induced myometrial relaxation. $\sp{125}$I-iodopindolol was used to assess $\beta$-adrenoceptor affinity and number cAMP levels were analyzed before and after stimulation by ...


Recovery Of Rna Polymerase Ii Synthesis Following Dna Damage In Mutants Of Saccharomyces Cerevisiae Defective In Nucleotide Excision Repair, Michael S. Reagan, Errol C. Friedberg Nov 1997

Recovery Of Rna Polymerase Ii Synthesis Following Dna Damage In Mutants Of Saccharomyces Cerevisiae Defective In Nucleotide Excision Repair, Michael S. Reagan, Errol C. Friedberg

Biology Faculty Publications

We have measured the kinetics of the recovery of mRNA synthesis in the inducible GAL10 and RNR3 genes after exposure of yeast cells to ultraviolet (UV) radiation. Such recovery is abolished in mutant strains defective in nucleotide excision repair (NER) of DNA, including a rad23 mutant. Mutants defective in the RAD7 or RAD16 genes, which are required for the repair of the non-transcribed strand but not the transcribed strand of transcriptionally active genes, show slightly faster recovery of RNA synthesis than wild-type strains. A strain deleted of the RAD26 gene, which is known to be required for strand-specific NER in ...


Changes Of Telomere Length Cause Reciprocal Changes In The Lifespan Of Mother Cells In Saccharomyces Cerevisiae, Father Nicanor Austriaco Sep 1997

Changes Of Telomere Length Cause Reciprocal Changes In The Lifespan Of Mother Cells In Saccharomyces Cerevisiae, Father Nicanor Austriaco

Rev. Nicanor Austriaco, O.P.

Budding yeast cells divide asymmetrically, giving rise to a mother and its daughter. Mother cells have a limited division potential, called their lifespan, which ends in proliferation-arrest and lysis. In this report we mutate telomerase in Saccharomyces cerevisiae to shorten telomeres and show that, rather than shortening lifespan, this leads to a significant extension in lifespan. This extension requires the product of the SIR3 gene, an essential component of the silencing machinery which binds to telomeres. In contrast, longer telomeres in a genotypically wild-type strain lead to a decrease in lifespan. These findings suggest that the length of telomeres dictates ...


Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters Jul 1997

Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters

Winfried S. Peters

Wounding-induced extracellular pH shifts were characterized previously in excised segments of maize (Zea mays L.) coleoptiles. In the present study it is demonstrated that similar pH shifts also occur in Triticum aestivum L., Secale cereale L., Hordeum vulgare L., Avena sativa L., Sorghum durra (Forsk.) Stapf, and Setaria italica (L.) Beauv., with characteristic quantitative differences between the species. Indole-acetic acid induces pronounced drops of the medium pH in all species except Setaria italica.


Goosecoid And Hnf-3beta Genetically Interact To Regulate Neural Tube Patterning During Mouse Embryogenesis, Stefania Filosa, Jaime A. Rivera-Pérez, Aitana Perea Gomez, Anne Gansmuller, Hitoshi Sasaki, Richard R. Behringer, Siew-Lan Ang Jul 1997

Goosecoid And Hnf-3beta Genetically Interact To Regulate Neural Tube Patterning During Mouse Embryogenesis, Stefania Filosa, Jaime A. Rivera-Pérez, Aitana Perea Gomez, Anne Gansmuller, Hitoshi Sasaki, Richard R. Behringer, Siew-Lan Ang

Rivera Lab Publications

The homeobox gene goosecoid (gsc) and the winged-helix gene Hepatic Nuclear Factor-3beta (HNF-3beta) are co-expressed in all three germ layers in the anterior primitive streak and at the rostral end of mouse embryos during gastrulation. In this paper, we have tested the possibility of functional synergism or redundancy between these two genes during embryogenesis by generating double-mutant mice for gsc and HNF-3beta. Double-mutant embryos of genotype gsc(-/-);HNF-3beta(+/-) show a new phenotype as early as embryonic days 8.75. Loss of Sonic hedgehog (Shh) and HNF-3beta expression was observed in the notochord and ventral neural tube of these embryos. These ...


Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle Jun 1997

Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle

Winfried S. Peters

In excised Zea mays L. coleoptiles incubated in aerated media at high fresh weight per volume ratios, indole-3-acetic acid induces transient drops of extracellular pH. Based on the quantitative dependency of the response on the initial auxin concentration we developed a novel auxin bioassay, which allows reliable estimation of IAA concentrations between 10−8.5 and 10−5 M. Using the bioassay and complementary concentration measurements by IAA fluorescence we found the transient IAA-induced pH response paralleled by a decrease of auxin activity and concentration in the medium. This decline is rapid and starts immediately upon auxin addition, and insofar ...


Measurements Of Serum Mullerian Inhibiting Substance In The Evaluation Of Children With Nonpalpable Gonads, Mary M. Lee, Patricia K. Donahoe, B. L. Silverman, T. Hasegawa, Yasuhiro Hasegawa, M. L. Gustafson, Y. C. Chang, David T. Maclaughlin May 1997

Measurements Of Serum Mullerian Inhibiting Substance In The Evaluation Of Children With Nonpalpable Gonads, Mary M. Lee, Patricia K. Donahoe, B. L. Silverman, T. Hasegawa, Yasuhiro Hasegawa, M. L. Gustafson, Y. C. Chang, David T. Maclaughlin

Lee Lab Publications

BACKGROUND: Mullerian inhibiting substance, produced constitutively by the prepubertal testes, promotes involution of the mullerian ducts during normal male sexual differentiation. In children with virilization and nonpalpable gonads, only those with testicular tissue should have detectable serum concentrations of mullerian inhibiting substance.

METHODS: We measured serum mullerian inhibiting substance in 65 children with virilization at birth and nonpalpable gonads (age at diagnosis, 2 days to 11 years) and serum testosterone in 54 of them either after the administration of human chorionic gonadotropin or during the physiologic rise in testosterone that occurs in normal infants.

RESULTS: The mean (+/-SD) serum mullerian ...


Endogenous Alkylglycerol Functions As A Mediator Of Protein Kinase C Activity And Cell Proliferation, Fritz G. Buchanan May 1997

Endogenous Alkylglycerol Functions As A Mediator Of Protein Kinase C Activity And Cell Proliferation, Fritz G. Buchanan

Electronic Theses and Dissertations

To explore the possibility that 1-O-alkyl-sn-glycerol (alkylglycerol) may serve a regulatory role in the control of cell proliferation or PKC activity, we examined the ability of alkylglycerol to influence PKC activity and subcellular distribution as well as the ability of alkylglycerol to effect cell proliferation. MDCK cells grown to confluence show a loss of PKC activity associated with the membrane, as reported in fibroblasts. Preconfluent cultures of MDCK cells have a high level of PKC activity associated with the membrane. However, treatment of preconfluent cultures with alkylglycerol causes a reduction of PKC activity. A similar inhibition was observed with alkylglycerol ...


Endosome To Golgi Retrieval Of The Vacuolar Protein Sorting Receptor, Vps10p, Requires The Function Of The Vps29, Vps30, And Vps35 Gene Products, Matthew N. J. Seaman, Eric G. Marcusson, Joan Lin-Cereghino, Scott D. Emr Apr 1997

Endosome To Golgi Retrieval Of The Vacuolar Protein Sorting Receptor, Vps10p, Requires The Function Of The Vps29, Vps30, And Vps35 Gene Products, Matthew N. J. Seaman, Eric G. Marcusson, Joan Lin-Cereghino, Scott D. Emr

College of the Pacific Faculty Articles

Mutations in the S. cerevisiae VPS29 and VPS30 genes lead to a selective protein sorting defect in which the vacuolar protein carboxypeptidase Y (CPY) is missorted and secreted from the cell, while other soluble vacuolar hydrolases like proteinase A (PrA) are delivered to the vacuole. This phenotype is similar to that seen in cells with mutations in the previously characterized VPS10 and VPS35 genes. Vps10p is a late Golgi transmembrane protein that acts as the sorting receptor for soluble vacuolar hydrolases like CPY and PrA, while Vps35p is a peripheral membrane protein which cofractionates with membranes enriched in Vps10p. The ...


Acid Phosphatase Content And Acidity Of The Perialgal Vacuole Of Ephydatia Muelleri, Camette Miller Apr 1997

Acid Phosphatase Content And Acidity Of The Perialgal Vacuole Of Ephydatia Muelleri, Camette Miller

Life and Environmental Sciences Undergraduate Theses

Freshwater sponges containing symbiotic algae can serve as a model for the study of relationships in which a host and an intracellular symbiont benefit. In freshwater sponges, symbiotic algae belonging to the genus, Chlorella, are housed in large cytoplasmic vacuoles, called perialgal vacuoles. I used microscopic techniques in an effort to determine whether the perialgal vacuoles ofthe freshwater sponge, Ephydatia muelleri, (1) contain active acid phosphatase, a lysosomal enzyme and (2) are acidic. Whereas the postcoupling method for localizing active acid phosphatase gave equivocal results, the Gomori method for localizing the enzyme revealed that few of the perialgal vacuoles possesed ...


Cγ- And Cα-Subunits Provide The Specificity For Camp/Pka Function, Wei Qing Zhang Apr 1997

Cγ- And Cα-Subunits Provide The Specificity For Camp/Pka Function, Wei Qing Zhang

Theses and Dissertations in Biomedical Sciences

The Cα and Cγ of the cAMP-dependent protein kinase (PKA) are two highly homologous (83% amino acid identity), yet functionally distinct isozymes in vitro for substrate and pseudosubstrate specificity, and in intact cells for cell phenotypes (Beebe, 1992).

To determine the molecular mechanisms underlying the distinct functions in cell phenotypes, in vitro experiments were designed to make a detailed comparison of Cγ and Cα for substrate and pseudosubstrate specificity. To this end, Cγ and Cα were expressed m mammalian cells, bacteria and Sf9 insect cells using baculovirus. Abundant expression of active enzyme was cell system specific. Cγ and Cα expressed ...


The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein Mar 1997

The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein

Winfried S. Peters

Relative elemental growth rate (REGR) profiles describe spatial patterns of growth intensity; they are indispensable for causal growth analyses. Published methods of REGR profile determination from marking experiments fall in two classes: the profile is either described by a series of segmental growth rates, or calculated as the slope of a function describing the displacement velocities of points along the organ. The latter technique is usually considered superior for theoretical reasons, but to our knowledge, no comparative methodological study of the two approaches is currently available. We formulated a model REGR profile that resembles those reported from primary roots. We ...


Beta-Actin Messenger Rna Localization And Protein Synthesis Augment Cell Motility, Edward H. Kislauskis, Xiaochun Zhu, Robert H. Singer Mar 1997

Beta-Actin Messenger Rna Localization And Protein Synthesis Augment Cell Motility, Edward H. Kislauskis, Xiaochun Zhu, Robert H. Singer

Open Access Articles

In chicken embryo fibroblasts (CEFs), beta-actin mRNA localizes near an actin-rich region of cytoplasm specialized for motility, the lamellipodia. This localization is mediated by isoform-specific 3'-untranslated sequences (zipcodes) and can be inhibited by antizipcode oligodeoxynucleotides (ODNs) (Kislauskis, E.H., X.-C. Zhu, and R.H. Singer. 1994. J. Cell Biol. 127: 441-451). This inhibition of beta-actin mRNA localization resulted in the disruption of fibroblast polarity and, presumably, cell motility. To investigate the role of beta-actin mRNA in motility, we correlated time-lapse images of moving CEFs with the distribution of beta-actin mRNA in these cells. CEFs with localized beta-actin mRNA ...


Mitochondrial Association Of A Plus End-Directed Microtubule Motor Expressed During Mitosis In Drosophila, Andrea J. Pereira, Brian Dalby, Russell J. Stewart, Stephen J. Doxsey, Lawrence S. B. Goldstein Mar 1997

Mitochondrial Association Of A Plus End-Directed Microtubule Motor Expressed During Mitosis In Drosophila, Andrea J. Pereira, Brian Dalby, Russell J. Stewart, Stephen J. Doxsey, Lawrence S. B. Goldstein

Open Access Articles

The kinesin superfamily is a large group of proteins (kinesin-like proteins [KLPs]) that share sequence similarity with the microtubule (MT) motor kinesin. Several members of this superfamily have been implicated in various stages of mitosis and meiosis. Here we report our studies on KLP67A of Drosophila. DNA sequence analysis of KLP67A predicts an MT motor protein with an amino-terminal motor domain. To prove this directly, KLP67A expressed in Escherichia coli was shown in an in vitro motility assay to move MTs in the plus direction. We also report expression analyses at both the mRNA and protein level, which implicate KLP67A ...


Analysis Of Gene Expression During Embryonic Development In Mulberry Silkworm Bombyx Mori, Amit Singh, K. P. Gopinathan Feb 1997

Analysis Of Gene Expression During Embryonic Development In Mulberry Silkworm Bombyx Mori, Amit Singh, K. P. Gopinathan

Biology Faculty Publications

We have developed a method for dechorionation and devitellinization of the silkworm eggs without damage, to facilitate the analysis of gene expression during embryonic development of Bombyx mori. Making use of antibodies available from heterologous systems, the spatio-temporal expression patterns of peroxidase and proliferating cell nuclear antigen have been directly visualized in whole mount embryos at various stages of development without the need for generating transformed ·lines carrying specific reporter constructs. The B. mori system, previously unamenable for such studies, could thus serve as an attractive model for molecular analysis of insect development.

The attention lavished on Drosophila melanogaster as ...


Introduction Of A [4fe-4s (S-Cys)4]+1,+2 Iron-Sulfur Center Into A Four-Α Helix Protein Using Design Parameters From The Domain Of The Fx Cluster In The Photosystem I Reaction Center, Marvin Paul Scott, John Biggins Feb 1997

Introduction Of A [4fe-4s (S-Cys)4]+1,+2 Iron-Sulfur Center Into A Four-Α Helix Protein Using Design Parameters From The Domain Of The Fx Cluster In The Photosystem I Reaction Center, Marvin Paul Scott, John Biggins

Agronomy Publications

We describe the insertion of an iron-sulfur center into a designed four α-helix model protein. The model protein was re-engineered by introducing four cysteine ligands required for the coordination of the mulinucleate cluster into positions in the main-chain directly analogous to the domain predicted to ligand the interpeptide [4Fe-4S (S-cys)4] cluster, Fx, from PsaA and PsaB of the Photosystem I reaction center. This was achieved by inserting the sequence, CDGPGRGGTC, which is conserved in PsaA and PsaB, into interhelical loops 1 and 3 of the four α-helix model. The holoprotein was characterized spectroscopically after insertion of the iron-sulfur center ...


A Heterodimer Of Thioredoxin And Ib2 Cooperates With Sec18p (Nsf) To Promote Yeast Vacuole Inheritance, Zuoyu Xu, Andreas Mayer, Eric Muller, William Wickner Jan 1997

A Heterodimer Of Thioredoxin And Ib2 Cooperates With Sec18p (Nsf) To Promote Yeast Vacuole Inheritance, Zuoyu Xu, Andreas Mayer, Eric Muller, William Wickner

Open Dartmouth: Faculty Open Access Scholarship

Early in S phase, the vacuole (lysosome) of Saccharomyces cerevisiae projects a stream of vesicles and membranous tubules into the bud where they fuse and establish the daughter vacuole. This inheritance reaction can be studied in vitro with isolated vacuoles. Rapid and efficient homotypic fusion between saltwashed vacuoles requires the addition of only two purified soluble proteins, Sec18p (NSF) and LMA1, a novel heterodimer with a thioredoxin subunit. We now report the identity of the second subunit of LMA1 as IB2, a previously identified cytosolic inhibitor of vacuolar proteinase B. Both subunits are needed for efficient vacuole inheritance in vivo ...


Assignment Of Fragile Site 8e (Fra8e) To Human Chromosome Band 8q24.11 Adjacent To The Hereditary Multiple Exostoses 1 Gene And Two Overlapping Langer-Giedion Syndrome Deletion Endpoints, April L. Hill, Y. Harada, E. Takahashi, J. Hou, M. J. Wagner, D. E. Wells Jan 1997

Assignment Of Fragile Site 8e (Fra8e) To Human Chromosome Band 8q24.11 Adjacent To The Hereditary Multiple Exostoses 1 Gene And Two Overlapping Langer-Giedion Syndrome Deletion Endpoints, April L. Hill, Y. Harada, E. Takahashi, J. Hou, M. J. Wagner, D. E. Wells

Biology Faculty Publications

The distamycin A inducible fragile site, FRA8E, Fra(8) (q24.11) has been previously mapped to 8q24.11, proximal to the MYC gene, by fluorescent in situ hybridization (Takahasi et al., 1991). This fragile site has been shown to be present in about 1 out of every 140 healthy Japanese individuals (Takahasi et al., 1988). To more precisely map FRA8E, we have used cosmids isolated from the Langer-Giedion chromosomal region (LGCR) for FISH analysis. Langer-Giedion syndrome (LGS) is a contiguous gene syndrome characterized by chromosome deletions in Sq24.11 (Ludecke et al., 1991). One of the genes known to be ...


Gene Expression Studies Of Murine Pregnancy Associated Granulated Metrial Gland And Decidual Cells , Melissa Phillips Allen Jan 1997

Gene Expression Studies Of Murine Pregnancy Associated Granulated Metrial Gland And Decidual Cells , Melissa Phillips Allen

Retrospective Theses and Dissertations

During pregnancy in viviparous mammals, the maternal decidua develops between the embryo and the uterine endometrium. This dissertation describes research on two different cell types present within the rodent decidua during pregnancy, namely, granulated metrial gland (GMG) cells and decidual cells;GMG cells are natural killer cells that proliferate and differentiate within the murine uterus during pregnancy. Their differentiation is associated with the accumulation of cytolytic mediators within cytoplasmic granules. The signaling mechanisms required for GMG cell differentiation, however, are largely unknown. In this study, expression of the genes coding for granzymes D, E, F, and G (granzymes D-G) was ...


The Drosophila Melanogaster Rad54 Homolog, Dmrad54, Is Involved In The Repair Of Radiation Damage And Recombination, Rolf Kooistra, José B. M. Zonneveld, Anja De Jong, Jan C. J. Eeken, Chris J. Osgood, Jean-Marie Buerstedde, Paul H. M. Lohman, Albert Pastink Jan 1997

The Drosophila Melanogaster Rad54 Homolog, Dmrad54, Is Involved In The Repair Of Radiation Damage And Recombination, Rolf Kooistra, José B. M. Zonneveld, Anja De Jong, Jan C. J. Eeken, Chris J. Osgood, Jean-Marie Buerstedde, Paul H. M. Lohman, Albert Pastink

Biological Sciences Faculty Publications

The RAD54 gene of Saccharomyces cerevisiae plays a crucial role in recombinational repair of double-strand breaks in DNA. Here the isolation and functional characterization of the RAD54 homolog of the fruit fly Drosophila melanogaster, DmRAD54, are described. The putative Dmrad54 protein displays 46 to 57% identity to its homologs from yeast and mammals. DmRAD54 RNA was detected at all stages of fly development, but an increased level was observed in early embryos and ovarian tissue. To determine the function of DmRAD54, a null mutant was isolated by random mutagenesis. DmRAD54-deficient flies develop normally, but the females are sterile. Early ...


The Immunomodulatory Effects Of 2-Deoxy-D-Glucose (2-Dg) And The Neuroendocrine Mediating Mechanisms , Shiu-Huey Chou Jan 1997

The Immunomodulatory Effects Of 2-Deoxy-D-Glucose (2-Dg) And The Neuroendocrine Mediating Mechanisms , Shiu-Huey Chou

Retrospective Theses and Dissertations

Studies of the effect of stress on the immune system provide a way to evaluate the coordination of the immune system with other systems in the maintenance of homeostasis. The objectives of the present study were to characterize the immunomodulatory effect of 2-DG, a metabolic stressor, on both primary and secondary immune organs and to examine the possible neuroendocrine mechanism(s) mediating 2-DG-induced immunomodulation using male, Lewis rats;The first study demonstrated that acute and chronic 2-DG administration induced a decrease total leukocyte counts, organ weight, IFN-[gamma] production, and mitogen response of lymphocytes in both spleen and whole blood ...


A System Of Reaction Diffusion Equations Arising In The Theory Of Reinforced Random Walks, Howard A. Levine, Brian D. Sleeman Jan 1997

A System Of Reaction Diffusion Equations Arising In The Theory Of Reinforced Random Walks, Howard A. Levine, Brian D. Sleeman

Mathematics Publications

We investigate the properties of solutions of a system of chemotaxis equations arising in the theory of reinforced random walks. We show that under some circumstances, finite-time blow-up of solutions is possible. In other circumstances, the solutions will decay to a spatially constant solution (collapse). We also give some intuitive arguments which demonstrate the possibility of the existence of aggregation (piecewise constant) solutions.


Regulation Of Intracellular Calcium Release During Fertilization In Sea Urchin Eggs , Shyh-Jye Lee Jan 1997

Regulation Of Intracellular Calcium Release During Fertilization In Sea Urchin Eggs , Shyh-Jye Lee

Retrospective Theses and Dissertations

The requirement for both inositol-1,4,5 trisphosphate (InsP3) and ryanodine-sensitive intracellular Ca2+ release mechanisms during fertilization was studied in sea urchin eggs. The postulated pathway of cGMP-dependent protein kinase (PKG) activation of ADP-ribosyl cyclase for production of cADPR to activate the ryanodine receptor Ca2+ channel was tested with a variety of activators and inhibitors. Our observations are consistent with Ca2+ release by cGMP in the egg being dependent on an isoform of PKG that is distinct from the mammalian enzyme. PKG activity in the sea urchin egg was activated by cIMP and was insensitive to cGMP analogs, which are ...


Abnormalities In Post-Translational Processing Of Platelet Rap 1b In Niddm: A Possible Cause Of Platelet Hyperactivity And Cardiovascular Disease In Diabetes, Elizabeth Ann Hall Jan 1997

Abnormalities In Post-Translational Processing Of Platelet Rap 1b In Niddm: A Possible Cause Of Platelet Hyperactivity And Cardiovascular Disease In Diabetes, Elizabeth Ann Hall

Theses and Dissertations in Biomedical Sciences

Post-translational processing is critical for the appropriate subcellular localization and function of platelet G-proteins. The majority of the platelet responses to agonists are mediated through specific receptor/G-protein complexes. Therefore, G-protein activity is central to "normal" platelet activity (i.e. aggregation). We have shown that Simvastatin, the in vivo inhibitor of HMG CoA Reductase and therefore isoprenoid synthesis, inhibits the post-translational processing of specific platelet G-proteins and alters platelet responses to agonists. These results show the importance of post-translational processing of G-proteins to platelet activity. Altered post-translational processing of specific G-proteins may explain platelet hyperactivity and the increased incidence of ...


Differential Glycosylation Of Tractin And Leechcam, Two Novel Ig-Superfamily Members, Regulates Neurite Extension And Fascicle Formation , Yueqiao Huang Jan 1997

Differential Glycosylation Of Tractin And Leechcam, Two Novel Ig-Superfamily Members, Regulates Neurite Extension And Fascicle Formation , Yueqiao Huang

Retrospective Theses and Dissertations

Specific carbohydrate structures on neural cell adhesion molecules are promising candidates for assisting in patterning neural connections during development. An excellent system to study the potential function of specific oligosaccharide modifications of neural proteins regulating pathway formation is in the projections of sensillar neurons in leech. At least five different monoclonal antibodies (Lan3-2, Lan2-3, Lan4-2, Laz2-369, Laz7-79) which recognize different glycoepitopes specific to the entire population as well as distinct subsets of these sensillar neurons have been identified. Their expression patterns and antibody perturbation studies are consistent with the hypothesis that a hierarchy of distinct carbohydrate structures expressed by specific ...