Cell and Developmental Biology Commons^™

Identification Of The Transactivation Domain Of The Transcription Factor Sox-2 And An Associated Co-Activator, Tamara K. Nowling, Lance R. Johnson, Matthew S. Wiebe, Angie Rizzino

Nebraska Center for Virology: Faculty Publications

The importance of interactions between Sox and POU transcription factors in the regulation of gene expression is becoming increasingly apparent. Recently, many examples of the involvement of Sox-POU partnerships in transcription have been discovered, including a partnership between Sox-2 and Oct-3. Little is known about the mechanisms by which these factors modulate transcription. To better understand the molecular interactions involved, we mapped the location of the transactivation do-main of Sox-2. This was done in the context of its interaction with Oct-3, as well as its ability to transactivate as a fusion protein linked to the DNA-binding domain of Gal4. Both …

Eph Receptors And Ephrins, Masaru Nakamoto

Biology Faculty Publications

The Eph receptors are the largest known family of receptor tyrosine kinases. The Eph receptors and theirmembrane-attached ligands, ephrins, show diverse expression patterns during development. Recent studies havedemonstrated that Eph receptors and ephrins play important roles in many developmental processes, includingneuronal network formation, the patterning of the neural tube and the paraxial mesoderm, the guidance of cellmigration, and vascular formation. In the nervous system, Eph receptors and ephrins have been shown to act aspositional labels to establish topographic projections. They also play a key role in pathway ®nding by axons andneural crest cells. The crucial roles of Eph receptors and …

The Life History Of The Cave Salamander, Eurycea Lucifuga Rafinesque, In West Virginia, Andrew James Longenecker

Theses, Dissertations and Capstones

In West Virginia, as throughout its range, there is limited information about the life history of the cave salamander (Eurycea lucifuga). The purpose of this study was to describe the natural history of this species in West Virginia. The objectives of this study were to determine habitat selection of the cave salamander, to ascertain its environmental characteristics, and to study its reproductive and non-reproductive biology. Three study caves were located in Greenbrier County, West Virginia. All sites were examined at least once each month from May 1999 through April 2000. Caves were divided into three zones: entrance, twilight, …

Ecology And Sympatric Relations Of Crevice Salamanders In Randolph County, West Virginia, Jayme Linn Waldron

Theses, Dissertations and Capstones

By implementing a mark-recapture study, I investigated the ecology of three species of sympatric plethodontid salamanders (Aneides aeneus, Desmognathus ochrophaeus, and Plethodon glutinosus) on rock outcrops in the Westvaco Wildlife and Ecosystem Research Forest, Randolph County, West Virginia. By examining activity patterns, vertical stratification, and habitat preference for A. aeneus, D. ochrophaeus, and P. glutinosus, I attempted to offer some insight into how these sympatric species avoid competition on small, isolated rock outcrops. Twenty-one surveys, both nocturnal and diurnal, were performed between 11 May and 17 October, 1999. During this time, 89 salamanders, encompassing five species ( …

Whole Animal And Cellular Strategies In The Regulation Of Bone Mass In The Rat, Weidong Geng

Theses, Dissertations and Capstones

In order to determine the strategies in regulation of bone mass in the rat and better understand the pathophysiological mechanism of the postmenopausal osteoporosis, a series of studies were conducted at the whole animal and cellular level. At the whole animal level, female Sprague-Dawley rats were ovariectomized (Ovx) or sham-operated (control) at 18 weeks and the entire skeleton obtained at 24 weeks (baseline) or after an additional 31 day (28 week) interval on a normal (1.0%) or deficient (0.02%) calcium diet. Ovx rats on the normal calcium diet showed a 42% increase in whole body bone resorption and a 70% …

Response Properties Of Tibial Campaniform Sensilla On The Cockroach Leg In Restrained Preparations And Freely Moving Animals, Angela L. Ridgel

Theses, Dissertations and Capstones

The ability to detect changes in forces is important for effective use of a leg in posture and locomotion. This thesis examines how forces are detected in the legs of cockroaches by tibial campaniform sensilla. Campaniform sensilla are mechanoreceptors that encode forces through ovoid cuticular caps embedded in the exoskeleton. The tibial sensilla are unique in that they consist of two subgroups with mutually perpendicular cap orientations.

We characterized the responses of the tibial receptors in restrained preparations by applying forces to the leg at controlled magnitudes and rates. The tibial sensilla, as a group, were sensitive to increasing and …

Mitochondrial 16s Rrna Gene As A Tool For Scorpion Systematics, Mark D. Barker

Theses, Dissertations and Capstones

The use of morphological analysis in the classification and phylogeny of scorpions often has led to confusion and controversy. In order to clarify these problems other character sets should be considered for analysis. One such tool is the use of molecular comparisons between organisms. This study used a section of the mitochondrial 16S ribosomal RNA gene. This technique was applied to investigate four scorpion genera belonging to three families: Hadruru, Anuroctonus (luridae), Euscorpius (Euscorpiidae), and Centruroides (Buthidae). Total DNA was extracted with a standard phenol/chloroform method; a gene of interest was amplified using PCR; and resulting DNA sequence analysis was …

Electroporation Dynamics In Biological Cells Subjected To Ultrafast Electrical Pulses: A Numerical Simulation Study, R. P. Joshi, K. H. Schoenbach

Bioelectrics Publications

A model analysis of electroporation dynamics in biological cells has been carried out based on the Smoluchowski equation. Results of the cellular response to short, electric pulses are presented, taking account of the growth and resealing dynamics of transient aqueous pores. It is shown that the application of large voltages alone may not be sufficient to cause irreversible breakdown, if the time duration is too short. Failure to cause irreversible damage at small pulse widths could be attributed to the time inadequacy for pores to grow and expand beyond a critical threshold radius. In agreement with earlier studies, it is …

Cellular Release Of And Response To Atp As Key Determinants Of The Set-Point Of Signal Transduction Pathways, Rennolds S. Ostrom, Caroline Gregorian, Paul A. Insel

Pharmacy Faculty Articles and Research

The determinants of “basal” activity of signaling pathways regulating cellular responses are poorly defined. One possibility is that cells release factors to establish the set-point of such pathways. Here we show that treatment of Madin-Darby canine kidney cells with the nucleotidase apyrase decreases basal arachidonic acid release and cAMP production 30–40% and that inhibitors of P2Y receptor action also affect basal and forskolin-stimulated cAMP accumulation. Changing medium prominently increases extracellular levels of ATP in Madin-Darby canine kidney, COS-7, and HEK-293 cells. Mechanical stimulation of ATP release likely occurs in virtually every experimental protocol with cultured cells, implicating such release and …

Tim18p Is A New Component Of The Tim54p-Tim22p Translocon In The Mitochondrial Inner Membrane, Oliver Kerscher, Naresh B. Sepuri, Robert E. Jensen

Arts & Sciences Articles

The mitochondrial inner membrane contains two separate translocons: one required for the translocation of matrix-targeted proteins (the Tim23p-Tim17p complex) and one for the insertion of polytopic proteins into the mitochondrial inner membrane (the Tim54p-Tim22p complex). To identify new members of the Tim54p-Tim22p complex, we screened for high-copy suppressors of the temperature-sensitivetim54-1 mutant. We identified a new gene,TIM18, that encodes an integral protein of the inner membrane. The following genetic and biochemical observations suggest that the Tim18 protein is part of the Tim54p-Tim22p complex in the inner membrane: multiple copies of TIM18 suppress thetim54-1 growth defect; the …

Human Gonadotropin-Releasing Hormone (Hgnrh) Gene Expression And Hormone Regulation In Human Placental Jeg-3 Cells, Heming Zheng

Theses and Dissertations in Biomedical Sciences

Using the human placental choriocarcinoma JEG-3 cell line as an in vitro human placental model, I studied the mechanisms of the tissue-specific expression and steroid hormone regulation of the hGnRH gene in the human placenta. The results showed that all of the previously identified four elements are required for the full activity of the hGnRH upstream promoter in JEG-3 cells, while the element 4 (FP4, −987/−968) is the most important. Studies performed with 5′ end deletion of this region confirmed these observations. Further, supershift assay using Oct-1 antibody demonstrated the involvement of Oct-1 in the FP4 DNA-protein interaction in JEG-3 …

Telomerase Activity In Human Preimplantation Embryos, Diane Lynne Wright

Theses and Dissertations in Biomedical Sciences

Telomerase, a ribonucleoprotein, has been described as an essential component of highly proliferative cells, which stabilizes the telomeres and avoids cellular senescence. Telomerase has been identified in various embryonic cell stages, hematopoietic cells, and in >85% of tumor tissue biopsies analyzed. The ability to measure the potential to proliferate successfully could provide an objective measure of an embryo's quality. The objectives of this study were to modify the telomeric repeat amplification protocol (TRAP) assay system for increased sensitivity to allow detection of telomerase activity in the single cell of an oocyte and embryo, obtain telomerase activity levels for the oocyte …

Mutations In The Protein Kinase A R1Α Regulatory Subunit Cause Familial Cardiac Myxomas And Carney Complex, Mairead Casy, Carl J. Vaughan, Jie He, Cathy J. Hatcher, Jordan M. Winter, Stanislawa Weremowicz, Kate Montgomery, Raju Kucherlapati, Cynthia C. Morton, Craig T. Bassoni

PCOM Scholarly Papers

Cardiac myxomas are benign mesenchymal tumors that can present as components of the human autosomal dominant disorder Carney complex. Syndromic cardiac myxomas are associated with spotty pigmentation of the skin and endocrinopathy. Our linkage analysis mapped a Carney complex gene defect to chromosome 17q24. We now demonstrate that the PRKAR1α gene encoding the R1α regulatory subunit of cAMP-dependent protein kinase A (PKA) maps to this chromosome 17q24 locus. Furthermore, we show that PRKAR1α frameshift mutations in three unrelated families result in haploinsufficiency of R1α and cause Carney complex. We did not detect any truncated R1α protein encoded by mutant PRKAR1α. …

Compartmental Specificity Of Cellular Membrane Fusion Encoded In Snare Proteins, James Mcnew, Frank Parlati, Ryorichi Fukuda, Robert Johnston, Keren Paz, Fabienne Paumet, Thomas Sollner, James Rothman

Fabienne Paumet

No abstract provided.

Soluble Nsf Attachment Protein Receptors (Snares) In Rbl-2h3 Mast Cells: Functional Role Of Syntaxin4 In Exocytosis And Identification Of A Vamp8-Containing Secretory Compartment, Fabienne Paumet, Joelle Le Mao, Sophie Martin, Thierry Galli, Bernard David, Ulrich Blank, Michele Roa

Fabienne Paumet

No abstract provided.

The Lin-4 Regulatory Rna Controls Developmental Timing In Caenorhabditis Elegans By Blocking Lin-14 Protein Synthesis After The Initiation Of Translation, Philip Olsen, Victor Ambros

Victor R. Ambros

lin-4 encodes a small RNA that is complementary to sequences in the 3' untranslated region (UTR) of lin-14 mRNA and that acts to developmentally repress the accumulation of LIN-14 protein. This repression is essential for the proper timing of numerous events of Caenorhabditis elegans larval development. We have investigated the mechanism of lin-4 RNA action by examining the fate of lin-14 mRNA in vivo during the time that lin-4 RNA is expressed. Our results indicate that the rate of synthesis of lin-14 mRNA, its state of polyadenylation, its abundance in the cytoplasmic fraction, and its polysomal sedimentation profile do not …

The Correlation Of Profiles Of Surface Ph And Elongation Growth In Maize Roots, Winfried Peters, Hubert Felle

Winfried S. Peters

The Kinesin-Related Protein, Hset, Opposes The Activity Of Eg5 And Cross-Links Microtubules In The Mammalian Mitotic Spindle, Vicki Mountain, Calvin Simerly, Louisa Howard, Asako Ando, Gerald Schatten, Duane A. Compton

Dartmouth Scholarship

We have prepared antibodies specific for HSET, the human homologue of the KAR3 family of minus end-directed motors. Immuno-EM with these antibodies indicates that HSET frequently localizes between microtubules within the mammalian metaphase spindle consistent with a microtubule cross-linking function. Microinjection experiments show that HSET activity is essential for meiotic spindle organization in murine oocytes and taxol-induced aster assembly in cultured cells. However, inhibition of HSET did not affect mitotic spindle architecture or function in cultured cells, indicating that centrosomes mask the role of HSET during mitosis. We also show that (acentrosomal) microtubule asters fail to assemble in vitro without …

Three-Dimensional Reconstructions Of Tadpole Chondrocrania From Histological Sections, Gary P. Radice, Mary Kate Boggiano, Mark Desantis, Peter M. Larson, Joseph Oppong, Matthew T. Smetanick, Todd M. Stevens, James Tripp, Rebecca A. Weber, Michael Kerckhove, Rafael O. De Sá

Biology Faculty Publications

Reconstructing three dimensional structures (3DR) from histological sections has always been difficult but is becoming more accessible with the assistance of digital imaging. We sought to assemble a low cost system using readily available hardware and software to generate 3DR for a study of tadpole chondrocrania. We found that a combination of RGB camera, stereomicroscope, and Apple Macintosh PowerPC computers running NIH Image, Object Image, Rotater. and SURFdriver software provided acceptable reconstructions. These are limited in quality primarily by the distortions arising from histological protocols rather than hardware or software.

Use Of Extractable Lipofuscin For Age Determination Of Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey

OES Faculty Publications

The blue crab Callinectes sapidus is an economically and ecologically important species in many temperate estuaries, yet stock assessments have been limited to length-based methods for demographic analyses. We evaluated the potential of age pigments (lipofuscins) sequestered in neural tissue of eye-stalks and brains to estimate the age of blue crabs collected from Chesapeake Bay and Chincoteague Bay. The rate of lipofuscin accumulation was determined using crabs of known age reared in the laboratory. Age pigments were extracted from neural tissues (eye-stalk or brain), quantified, and normalized to protein content to allow comparisons across tissue types and crab sizes. Field-collected …

Optimal Replication Activity Of Vesicular Stomatitis Virus Rna Polymerase Requires Phosphorylation Of A Residue(S) At Carboxy-Terminal Domain Ii Of Its Accessory Subunit, Phosphoprotein P, Leroy N. Hwang, Nathan Englund, Tapas Das, Amiya K. Florida, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

The phosphoprotein, P, of vesicular stomatitis virus (VSV) is a key subunit of the viral RNA-dependent RNA polymerase complex. The protein is phosphorylated at multiple sites in two different domains. We recently showed that specific serine and threonine residues within the amino-terminal acidic domain I of P protein must be phosphorylated for in vivo transcription activity, but not for replication activity, of the polymerase complex. To examine the role of phosphorylation of the carboxy-terminal domain II residues of the P protein in transcription and replication, we have used a panel of mutant P proteins in which the phosphate acceptor sites …

Identification And Characterization Of Determinants Of Head And Neck Tumor Cell Invasion, Yangguan Wu

Theses and Dissertations in Biomedical Sciences

Head and neck squamous cell carcinoma (HNSCC) is a common malignant disease with poor prognosis. The majority of patients die from local invasion or lymphatic metastasis. The mechanism(s) underlining the invasiveness of HNSCC are poorly understood. Utilizing a panel of HNSCC cell lines previously established in our laboratory, we tested the application and relevance of the three-step hypothesis of tumor invasion to HNSCC and investigated the mechanism(s) pertaining to the regulation of each step in the invasive process. Data presented in this thesis demonstrated that tumor cell invasion in HNSCC is a complex process involving three repeated sequential steps: adhesion, …

Tissue-Specific Expression And Steroid Hormone Regulation Of Human Gonadotropin -Releasing Hormone (Hgnrh) Gene In Placental Cells (Jeg -3 Cells), Zhengguang Chen

Theses and Dissertations in Biomedical Sciences

Using JEG-3 cells as an in vitro model, I investigated the mechanisms behind the tissue-specific expression and steroid hormone regulation of the hGnRH gene in the human placenta. The hGnRH upstream promoter was found to be functionally active in JEG-3 cells. The DNA sequence responsible for functioning of the upstream promoter in JEG-3 cells is narrowed to a region between –1048 bp and –730 bp. This DNA fragment contains four elements, which can bind with nuclear extract from JEG-3 cells (but not from GT1-7 cells).

Estradiol (E2) represses the hGnRH upstream promoter activity in JEG-3 cells. This inhibition is receptor-mediated, …

Estructura Del Condrocráneo Y Esqueleto Visceral De Larvas De Pseudis Minuta (Anura, Pseudidae, E. O. Lavilla, Rafael O. De Sá

Biology Faculty Publications

The chondrocranium and visceral skeleton of Pseudis minuta tadpoles are described, based on a series of five larvae in stages 31 - 35 of Gosner (1960). Among their striking characters are the presence of peculiar articular surfaces between cornua trabeculae and suprarostral cartilage, the incomplete development of the orbital cartilage, the high fenestration of the floor of the cavum cranii, the fusion of posterior foramina, and the fusion of spicules 3 and 4 in the hyobranchial skeleton.

The Timing And Pattern Of Myogenesis In Hymenochirus Boettgeri, Matthew T. Smetanick, Rafael O. De Sá

Biology Faculty Publications

Differences in the relative timing of homologous developmental events among closely related species, known as heterochronies, may provide valuable clues in understanding evolutionary relationships (McKinney, 1988; McNamara, 1995). Examining the timing of myogenic events is a relatively easy and effective method for finding heterochronic events. For example, whether muscle proteins and myofibrils appear before or after multinucleation can be determined through histological techniques (Kielbowna, 1981). Simple observations of live specimens can pinpoint functional landmarks such as first twitch (spontaneous or due to external stimuli) and first heartbeat.

The Timing Oflin-4rna Accumulation Controls The Timing Of Postembryonic Developmental Events Incaenorhabditis Elegans, Rhonda Feinbaum, Victor Ambros

Victor R. Ambros

The lin-4 gene encodes a small RNA that is required to translationally repress lin-14 toward the end of the first larval stage of Caenorhabditis elegans development. To determine if the timing of LIN-14 protein down-regulation depends on the temporal profile of lin-4 RNA level, we analyzed the stage-specificity of lin-4 RNA expression during wild-type development and examined the phenotypes of transgenic worms that overexpress lin-4 RNA during the first larval stage. We found that lin-4 RNA first becomes detectable at approximately 12 h of wild-type larval development and rapidly accumulates to nearly maximum levels by 16 h. This profile of …

Cell Cycle-Dependent Sequencing Of Cell Fate Decisions In Caenorhabditis Elegans Vulva Precursor Cells, Victor Ambros

Victor R. Ambros

In Caenorhabditis elegans, the fates of the six multipotent vulva precursor cells (VPCs) are specified by extracellular signals. One VPC expresses the primary (1 degrees ) fate in response to a Ras-mediated inductive signal from the gonad. The two VPCs flanking the 1 degrees cell each express secondary (2 degrees ) fates in response to lin-12-mediated lateral signaling. The remaining three VPCs each adopt the non-vulval tertiary (3 degrees ) fate. Here I describe experiments examining how the selection of these vulval fates is affected by cell cycle arrest and cell cycle-restricted lin-12 activity. The results suggest that lin-12 participates …

Development Of The Suprarostral Plate Of Pipoid Frogs, Rafael O. De Sá, Charles C. Swart

Biology Faculty Publications

The rostral region of nonpipoid tadpoles has two sets of cartilages, the cornua trabeculae and the suprarostral cartilages, whereas the rostral region in pipoid larvae is occupied by a single and continuous cartilage, the suprarostral plate. The homology of this region in pipoid and nonpipoids tadpoles has been controversial. We examined the early formation and development of the suprarostral plate using serially cross-sectioned specimens of Rhinophrynus, Xenopus, and Hymenochirus. We conclude that the cartilaginous structures present in the rostral area of pipoid and nonpipoid larvae are homologous. Furthermore, we found two different developmental patterns among pipoid larvae. The chondrocranium …

Cell Cycle-Dependent Sequencing Of Cell Fate Decisions In Caenorhabditis Elegans Vulva Precursor Cells, Victor Ambros

Dartmouth Scholarship

In Caenorhabditis elegans, the fates of the six multipotent vulva precursor cells (VPCs) are specified by extracellular signals. One VPC expresses the primary (1°) fate in response to a Ras-mediated inductive signal from the gonad. The two VPCs flanking the 1° cell each express secondary (2°) fates in response to lin-12-mediated lateral signaling. The remaining three VPCs each adopt the non- vulval tertiary (3°) fate. Here I describe experiments examining how the selection of these vulval fates is affected by cell cycle arrest and cell cycle-restricted lin-12 activity. The results suggest that lin-12 participates in two

INTRODUCTION

Cell-cell signaling is …

Xet-Related Genes And Growth Kinematics In Barley Leaves, Winfried Peters, Wieland Fricke, Peter Chandler

Winfried S. Peters