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Full-Text Articles in Cell Biology

Characterizing The Polycation Receptor Of Paramecium, Eric D. Robinette, Heather G. Kuruvilla Dec 2006

Characterizing The Polycation Receptor Of Paramecium, Eric D. Robinette, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

Unicellular eukaryotes are complex systems, performing all the tasks needed for survival within the context of a single cell. Protozoans, such as Tetrahymena and Paramecium, use chemosensory systems to detect food and to avoid predation.

Both Tetrahymena and Paramecium have been used as models for studying chemorepellents. Lysozyme, ATP, and GTP have been found to have chemorepellent activity in both ciliates. In Tetrahymena, several PACAP isoforms have been shown to bind to the same receptor as lysozyme, indicating that this receptor may be a more general “polycation receptor” (Keedy et al., 2003). The polycation receptor in Tetrahymena appears to be ...


Lobe And Serrate Are Required For Cell Survival During Early Eye Development In Drosophila, Amit Singh, Xiao Shi, Kwang-Wook Choi Nov 2006

Lobe And Serrate Are Required For Cell Survival During Early Eye Development In Drosophila, Amit Singh, Xiao Shi, Kwang-Wook Choi

Biology Faculty Publications

Organogenesis involves an initial surge of cell proliferation, leading to differentiation. This is followed by cell death in order to remove extra cells. During early development, there is little or no cell death. However, there is a lack of information concerning the genes required for survival during the early cell-proliferation phase. Here, we show that Lobe (L) and the Notch (N) ligand Serrate (Ser), which are both involved in ventral eye growth, are required for cell survival in the early eye disc. We observed that the loss-of-ventral-eye phenotype in L or Ser mutants is due to the induction of cell ...


The Fat Cadherin Acts Through The Hippo Tumor-Suppressor Pathway To Regulate Tissue Size, Maria Willecke, Fisun Hamaratoglu, Madhuri Kango-Singh, Ryan Udan, Chiao-Lin Chen, Chunyao Tao, Xinwei Zhang, Georg Halder Nov 2006

The Fat Cadherin Acts Through The Hippo Tumor-Suppressor Pathway To Regulate Tissue Size, Maria Willecke, Fisun Hamaratoglu, Madhuri Kango-Singh, Ryan Udan, Chiao-Lin Chen, Chunyao Tao, Xinwei Zhang, Georg Halder

Biology Faculty Publications

Background: The Hippo tumor-suppressor pathway has emerged as a key signaling pathway that controls tissue size in Drosophila. Merlin, the Drosophila homolog of the human Neurofibromatosis type-2 (NF2) tumor-suppressor gene, and the related protein Expanded are the most upstream components of the Hippo pathway identified so far. However, components acting upstream of Expanded and Merlin, such as transmembrane receptors, have not yet been identified.

Results: Here, we report that the protocadherin Fat acts as an upstream component in the Hippo pathway. Fat is a known tumor-suppressor gene in Drosophila, and fat mutants have severely overgrown imaginal discs. We found that ...


Expression Of The Primary Carbohydrate Component Of The Bordetella Bronchiseptica Biofilm Matrix Is Dependent On Growth Phase But Independent Of Bvg Regulation, Yasuhiko Irie, Andrew Preston, Ming H. Yuk Sep 2006

Expression Of The Primary Carbohydrate Component Of The Bordetella Bronchiseptica Biofilm Matrix Is Dependent On Growth Phase But Independent Of Bvg Regulation, Yasuhiko Irie, Andrew Preston, Ming H. Yuk

Biology Faculty Publications

We previously showed that the Bvg virulence control system regulates biofilm formation in Bordetella bronchiseptica (Y. Irie, S. Mattoo, and M. H. Yuk, J. Bacteriol. 186:5692-5698, 2004). Analyses of the extracellular components of B. bronchiseptica biofilm matrix revealed that the major sugar component in the matrix was xylose, and linkage analysis indicated a majority of it to be in a 4-linked polymeric form. The production of xylose was independent of Bvg regulation but instead was dependent on bacterial growth phase. In addition, N-acetyl-glucosamine in the matrix was found to be important for the initial development of the biofilm ...


A Kinesin-Like Calmodulin-Binding Protein In Chlamydomonas: Evidence For A Role In Cell Division And Flagellar Functions, Erin E. Dymek, Daniel Goduti, Tal Kramer, Elizabeth F. Smith May 2006

A Kinesin-Like Calmodulin-Binding Protein In Chlamydomonas: Evidence For A Role In Cell Division And Flagellar Functions, Erin E. Dymek, Daniel Goduti, Tal Kramer, Elizabeth F. Smith

Open Dartmouth: Faculty Open Access Scholarship

Kinesin-like calmodulin-binding protein, KCBP, is a novel member of the C-kinesin superfamily first discovered in flowering plants. This minus-end-directed kinesin exhibits Ca(2+)-calmodulin-sensitive motor activity in vitro and has been implicated in trichome morphogenesis and cell division. A homologue of KCBP is also found in the unicellular, biflagellate green alga Chlamydomonas reinhardtii (CrKCBP). Unlike plant cells, Chlamydomonas cells do not form trichomes and do not assemble a phragmoplast before cell division. To test whether CrKCBP is involved in additional microtubule-based processes not observed in plants, we generated antibodies against the putative calmodulin-binding domain and used these antibodies in biochemical ...


Exogenous Expression Of Human Na, K-Atpase Isoforms In Insect Cells, Christal Renee' Carpenter Apr 2006

Exogenous Expression Of Human Na, K-Atpase Isoforms In Insect Cells, Christal Renee' Carpenter

McCabe Thesis Collection

The Na-K-ATPase or Na pump is a membrane bound enzyme that maintains a high concentration of K+ and low concentration of Na+ in most animal cells. Three subunits constitute the Na pump, named alpha (ex), beta (~). and gamma (y). The ex subunit is responsible for the catalytic and transport of the enzyme, the ~ subunit is important for bringing the ex to the plasma membrane of the cell, and y is a regulatory subunit of the Na pump. In addition, there are several molecular variants or isoforms of the ex and ~ subunits. At present four different ex (ex 1, ex2, ex3 ...


Olfactory Bulb Neurons Of Adult Zebrafish Morphology, Distribution, Cellular Interactions And Structural Stability Following Deafferentation, Cynthia L. Fuller Apr 2006

Olfactory Bulb Neurons Of Adult Zebrafish Morphology, Distribution, Cellular Interactions And Structural Stability Following Deafferentation, Cynthia L. Fuller

Dissertations

The zebrafish is becoming an increasingly popular model for studies involving olfactory function, yet there is still much to be learned about the anatomy and circuitry of different cell types in the olfactory bulb. This study focuses on identifying the morphology and distribution of output neurons and interneurons in the olfactory bulb of adult zebrafish, Danio rerio . Furthermore, this investigation examines the cellular interactions of the primary output neuron, the mitral cell, and addresses the issue of neuronal plasticity by considering the structural stability of this cell type following loss of afferent innervation.

Using retrograde tract tracing with various dextrans ...


Affecting Wnt3a In The Inner Ear Of Xenopus Laevis, Heather Elina Hodges Jan 2006

Affecting Wnt3a In The Inner Ear Of Xenopus Laevis, Heather Elina Hodges

Undergraduate Honors Theses

Problems associated with the development of the ear can result in vertigo and partial or complete hearing loss. Efforts to better understand the development of the inner ear have been made in mouse, frog, chick, and other species. However, there is still relatively little known about the mechanisms that control the processes during development. This research has used the African Clawed Frog, Xenopus laevis, to study embryonic and inner ear development. The gene Wnt3a was previously determined to be expressed in the dorsal half of the developing otocyst. This suggested a possible role for Wnt3a in inner ear development, but ...


Endothelial Cell Cortactin Phosphorylation By Src Contributes To Polymorphonuclear Leukocyte Transmigration In Vitro, L. Yang, Jennifer R. Kowalski, X. Zhan, S. M. Thomas, F. W. Luscinskas Jan 2006

Endothelial Cell Cortactin Phosphorylation By Src Contributes To Polymorphonuclear Leukocyte Transmigration In Vitro, L. Yang, Jennifer R. Kowalski, X. Zhan, S. M. Thomas, F. W. Luscinskas

Scholarship and Professional Work - LAS

The underlying mechanisms that regulate leukocyte transendothelial migration through the vascular endothelium remain unclear. Cortactin is a substrate of Src tyrosine kinases and a regulator of cytoskeletal dynamics. Previous studies demonstrated a role for Src phosphorylation of cortactin in clustering of E-selectin and intercellular cell adhesion molecule-1 around adherent leukocytes. In the current study, we used an in vitro flow model to investigate the role of Src-induced cortactin phosphorylation in endothelium during polymorphonuclear leukocyte (PMN) transmigration through human umbilical vein endothelium (HUVEC) monolayers preactivated with tumor necrosis factor-{alpha}. Inhibition of Src in HUVEC using Src kinase inhibitors PP2 and ...


Eye Development At The Houston "Fly Meeting", Amit Singh Jan 2006

Eye Development At The Houston "Fly Meeting", Amit Singh

Biology Faculty Publications

Meeting report: The 47th Annual Drosophila Research Conference or "Fly Meeting" took place at Houston, Texas, USA from March 29th- April 2nd, 2006, under the aegis of the Genetics Society of America. The Fly Meeting provides an excellent opportunity for fly researchers to present their work and to get a snapshot of recent developments and upcoming trends in their research field. The fruit fly, Drosophila melanogaster, is a very versatile model to study growth, patterning, neural development, evolution, systemetics and various other facets of biomedical science. The topics presented in the meeting covered a very broad spectrum of fly research ...