Life Sciences Commons^™

Do Timing And Pattern Of Myogenesis Correlate With Life History Mode In Anurans?, Matthew T. Smetanick, Rafael O. De Sá, Gary P. Radice

Biology Faculty Publications

The timing and pattern of myogenesis varies among anurans that have been studied and the different pat- terns may provide useful phylogenetic information. Specific myogenic markers have been described (Muntz, 1975; Kielbowna, 1981; Boudjelida & Muntz, 1987; Radice et al., 1989) and they can provide infor- mation on evolutionary changes for closely related lineages within a clade. For example, we previously com- pared first appearance of a muscle-specific protein, first twitch of axial muscle, onset of multinucleation within axial myotome, and first heartbeat in two pipid genera (Smetanick et al., 1999). We found that although the timing of myogenesis differed, …

Control Of Developmental Timing In Caenorhabditis Elegans, Victor Ambros

Victor R. Ambros

Studies of the nematode Caenorhabditis elegans have identified genetic and molecular mechanisms controlling temporal patterns of developmental events. Mutations in genes of the C. elegans heterochronic pathway cause altered temporal patterns of larval development, in which cells at certain larval stages execute cell division patterns or differentiation programs normally specific for other stages. The products of the heterochronic genes include transcriptional and translational regulators and two different cases of novel small translational regulatory RNAs. Other genes of the pathway encode evolutionarily conserved proteins, including a homolog of the Drosophila Period circadian timing regulator, and a member of the nuclear receptor …

The Mechanic State Of “Inner Tissue” In The Growing Zone Of Sunflower Hypocotyls And The Regulation Of Its Growth Rate Following Excision, Winfried Peters, A. Tomos

Winfried S. Peters

The Lin-41 Rbcc Gene Acts In The C. Elegans Heterochronic Pathway Between The Let-7 Regulatory Rna And The Lin-29 Transcription Factor, Frank Slack, Michael Basson, Zhongchi Liu, Victor Ambros, H. Horvitz, Gary Ruvkun

Victor R. Ambros

Null mutations in the C. elegans heterochronic gene lin-41 cause precocious expression of adult fates at larval stages. Increased lin-41 activity causes the opposite phenotype, reiteration of larval fates. let-7 mutations cause similar reiterated heterochronic phenotypes that are suppressed by lin-41 mutations, showing that lin-41 is negatively regulated by let-7. lin-41 negatively regulates the timing of LIN-29 adult specification transcription factor expression. lin-41 encodes an RBCC protein, and two elements in the lin-413'UTR are complementary to the 21 nucleotide let-7 regulatory RNA. A lin-41::GFP fusion gene is downregulated in the tissues affected by lin-41 at the time that the let-7 …

Structure And Function Analysis Of Lin-14, A Temporal Regulator Of Postembryonic Developmental Events In Caenorhabditis Elegans, Yang Hong, Rosalind C. Lee, Victor R. Ambros

Victor R. Ambros

During postembryonic development of Caenorhabditis elegans, the heterochronic gene lin-14 controls the timing of developmental events in diverse cell types. Three alternative lin-14 transcripts are predicted to encode isoforms of a novel nuclear protein that differ in their amino-terminal domains. In this paper, we report that the alternative amino-terminal domains of LIN-14 are dispensable and that a carboxy-terminal region within exons 9 to 13 is necessary and sufficient for in vivo LIN-14 function. A transgene capable of expressing only one of the three alternative lin-14 gene products rescues a lin-14 null mutation and is developmentally regulated by lin-4. This shows …

What Makes Plants Different? Principles Of Extracellular Matrix Function In 'Soft' Plant Tissues [Review Article], Winfried Peters, Wolfgang Hagemann, A. Tomos

Winfried S. Peters

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 ( …

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 …

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. …