Cell Biology Commons^™

Numa Assembles Into An Extensive Filamentous Structure When Expressed In The Cell Cytoplasm, Alejandro Saredi, Louisa Howard, Duane A. Compton

Dartmouth Scholarship

NuMA is a 236 kDa protein that participates in the organization of the mitotic spindle despite its strict localization in the nucleus during interphase. To test how cells progress through mitosis when NuMA is localized in the cytoplasm instead of the nucleus, we have deleted the nuclear localization sequence of NuMA using site-directed mutagenesis and transiently expressed this mutant protein (NuMA-DeltaNLS) in BHK-21 cells. During interphase, NuMA-DeltaNLS accumulates in the cytoplasm as a large mass approximately the same size as the cell nucleus. When cells enter mitosis, NuMA-DeltaNLS associates normally with the mitotic spindle without causing any apparent deleterious effects …

The Epidermis Still In Control?, Winfried Peters, A. Tomos

Winfried S. Peters

The History Of Tissue Tension, Winfried S. Peters, A. Deri Tomos

Winfried S. Peters

Reversal Of Cell Fate Determination In Caenorhabditis Elegans Vulval Development, Susan Euling, Victor Ambros

Dartmouth Scholarship

In Caenorhabditis elegans, the fates of the multipotent vulval precursor cells (VPCs) are specified by intercellular signals, The VPCs divide in the third larval stage (L3) of the wild type, producing progeny of determined cell types, In lin-28 mutants, vulva development is similar to wild-type vulva development except that it occurs precociously, in the second larval stage (L2), Consequently, when lin-28 hermaphrodites temporarily arrest development at the end of L2 in the dauer larva stage, these otherwise determined VPC progeny become reprogrammed back to the multipotent, signal- sensitive state of VPCs. Our results indicate that VPC fate determination by intercellular …

The Evaluation Of Succinylcholine Chloride For Harmful Effects Upon Early-Stage Mouse Embryos, Francis Warren Prescott

Biological Sciences Theses & Dissertations

Succinylcholine (SCh) chloride is a depolarizing neuromuscular blocking agent used to paralyze patients for surgical procedures. Over 1,800 clinical observations of newborn infants have demonstrated that succinylcholine does not cross the placenta in quantities detrimental to fetuses (Kolstad, et al., 1957, Bakhoum, et al., 1957, Hodges, et al., 1959, Duffield, et al., 1958, Dennis, et al., 1954, 1956, McNab, 1955, Coleman, et al., 1956, Lund, 1953). Later investigations which involved comparison of blood levels of SCh in the mother to those in fetuses bolstered the finding that SCh fails to cross the placenta in significant amounts (Moya and Kvisselgaard, 1961, …

Heat Shock Factor Gains Access To The Yeast Hsc82 Promoter Independently Of Other Sequence-Specific Factors And Antagonizes Nucleosomal Repression Of Basal And Induced Transcription, Alexander M. Erkine, C. C. Adams, T. Diken, D. S. Gross

Scholarship and Professional Work – COPHS

Transcription in eukaryotic cells occurs in the context of chromatin. Binding of sequence-specific regulatory factors must contend with the presence of nucleosomes for establishment of a committed preinitiation complex. Here we demonstrate that the high-affinity binding site for heat shock transcription factor (HSF) is occupied independently of other cis-regulatory elements and is critically required for preventing nucleosomal assembly over the yeast HSC82 core promoter under both noninducing (basal) and inducing conditions. Chromosomal mutation of this sequence, termed HSE1, erases the HSF footprint and abolishes both transcription and in vivo occupancy of the TATA box. Moreover, it dramatically reduces promoter chromatin …

Genetic Analysis Of Rhinichthys Atratulus (Pisces: Cyprinidae) In North Central West Virginia, Alan Harper Tennant

Theses, Dissertations and Capstones

The blacknose dace, Rhinichthys atratulus, is a cyprinid minnow common to shallow streams throughout North America. It has been shown to be sensitive to anthropogenic stress and a study of the genetic nature of R. atratulus populations may yield information about their habitats. In West Virginia, two subspecies of R. atratulus are present, R. a. atratulus and R. a. obtusus, which are separated by the Allegheny divide. In north central West Virginia, R. a. atratulus was observed in the Cheat River drainage, an area previously thought be within the range of R. a. obtusus. Fish of the R. a. atratulus …

Examination Of The Cell Wall Of Micrasterias Radiosa Var Radiosa (Conjugatophyceae) By Transmission And Scanning Electron Microscopy, Jennifer A. Akin, Richard L. Meyer

Journal of the Arkansas Academy of Science

The cell wall of Micrasterias radiosa var. radiosa Ralfs 1848 (Conjugatophyceae) was examined by transmission and scanning electron microscopy. Previous electron microscopy of this taxon has not been performed; thus these are new observations. The cell wall was recognized to be of the Cosmarium type with complex pores external to the plasma membrane that penetrate the secondary wall and with ornamentation arising from the secondary wall. Subdivided regions of the pore apparatus, the pore head, pore bulb, connecting pore channel, and pore depression were detected. Pores of type 4 were located in the isthmal region and at the division of …

Modulation Of Queuine Uptake And Incorporation Into Trna By Protein Kinase C And Protein Phosphatase, Rana C. Morris, Bonnie J. Brooks, K. Lenore Hart, Mark S. Elliot

Chemistry & Biochemistry Faculty Publications

It has been suggested that the rate of queuine uptake into cultured human fibroblasts is controlled by phosphorylation levels within the cell. We show that the uptake of queuine is stimulated by activators of protein kinase C (PKC) and inhibitors of protein phosphatase; while inhibitors of PKC, and down-regulation of PKC by chronic exposure to phorbol esters inhibit the uptake of queuine into cultured human fibroblasts. Activators of cAMP- and cGMP-dependent kinases exert no effect on the uptake of queuine into fibroblast cell cultures. These studies suggest that PKC directly supports the activity of the queuine uptake mechanism, and that …