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Full-Text Articles in Life Sciences
Sensory Transduction In The Vomeronasal Organ: The Role Of Protein Interactions, Jessica Brann
Sensory Transduction In The Vomeronasal Organ: The Role Of Protein Interactions, Jessica Brann
Jessica Brann
This dissertation discusses signal transduction cascades in the vomeronasal organ (VNO) of the stinkpot turtle, Sternotherus odoratus and the Sprague-Dawley rat by investigating downstream signaling events leading to a vomeronasal receptor potential in response to a species-specific chemical. The VNO is the receptor portion of a distinct olfactory system found in most vertebrates that normally functions to detect socially relevant chemical cues. It is thought that chemical communication is transduced when a ligand (chemical or pheromone) binds to a G protein-coupled receptor (GPCR) in the plasma membrane of a vomeronasal sensory neuron (VSN). The G protein-coupled receptors are located on …
Partial Replacement Of Nacl Can Be Achieved With Potassium, Magnesium And Calcium Salts In Brown Bread, Karen Charlton, Naomi Levitt, Krisela Steyn, Elizabeth Macgregor, Nonnie Vorster
Partial Replacement Of Nacl Can Be Achieved With Potassium, Magnesium And Calcium Salts In Brown Bread, Karen Charlton, Naomi Levitt, Krisela Steyn, Elizabeth Macgregor, Nonnie Vorster
Karen E. Charlton
Objectives: To develop a reduced sodium bread in which salt (NaCl) is partially replaced with K, Mg, and Ca salts. Methods: Experimental bread was compared against standard brown bread, after a drop test (to assess whether bread quality deteriorates with abuse) and after usual baking practices for baking properties (volume, crust colour, crumb colour and cell structure), sensory properties and nutritional composition. Plant production feasibility was evaluated in an industrial plant. Breads produced there were subjected to sensory evaluation using triangulation tests in a panel of 122 consumers. Twenty-four samples of both standard and experimental bread were laboratory-analysed for Na, …
Analysis Of The Mechanism By Which Calcium Negatively Regulates The Tyrosine Phosphorylation Cascade Associated With Sperm Capacitation, Mark Baker, Louise Hethrington, Heath Ecroyd, Shaun Roman, Robert Aitken
Analysis Of The Mechanism By Which Calcium Negatively Regulates The Tyrosine Phosphorylation Cascade Associated With Sperm Capacitation, Mark Baker, Louise Hethrington, Heath Ecroyd, Shaun Roman, Robert Aitken
Heath Ecroyd
The capacitation of mammalian spermatozoa involves the activation of a cAMP-mediated signal transduction pathway that drives tyrosine phosphorylation via mechanisms that are unique to this cell type. Controversy surrounds the impact of extracellular calcium on this process, with positive and negative effects being recorded in independent publications. We clearly demonstrate that the presence of calcium in the external medium decreases tyrosine phosphorylation in both human and mouse spermatozoa. Under these conditions, a rise in intracellular pH was recorded, however, this event was not responsible for the observed changes in phosphotyrosine expression. Rather, the impact of calcium on tyrosine phosphorylation in …
The Development Of Signal Transduction Pathways During Epididymal Maturation Is Calcium Dependent, Heath W. Ecroyd, Kelly Asquith, Russell C. Jones, Robert J. Aitken
The Development Of Signal Transduction Pathways During Epididymal Maturation Is Calcium Dependent, Heath W. Ecroyd, Kelly Asquith, Russell C. Jones, Robert J. Aitken
Heath Ecroyd
Capacitation has been correlated with the activation of a cAMP-PKA-dependent signaling pathway leading to protein tyrosine phosphorylation. The ability to exhibit this response to cAMP matures during epididymal maturation in concert with the ability of the sperrnatozoa to capacitate. In this study, we have addressed the mechanisms by which spermatozoa gain the potential to activate this signaling pathway during epididymal maturation. In a modified Tyrode's medium containing 1.7 mM calcium, caput spermatozoa had significantly higher [Ca2+](i) than caudal cells and could not tyrosine phosphorylate in response to cAMP. However, in calcium-depleted medium both caput and caudal cells could exhibit a …
An Evaluation Of The Nutritional Quality Evaluation Of Three Cultivars Of Syzygium Samarangense Under Malaysian Conditions, Amru Bin Nasrulhaq Boyce
An Evaluation Of The Nutritional Quality Evaluation Of Three Cultivars Of Syzygium Samarangense Under Malaysian Conditions, Amru Bin Nasrulhaq Boyce
Amru Bin Nasrulhaq Boyce
A study was carried out to selected physiological and biochemical characteristics of Syzygium samarangense for their physiological and biochemical characteristics at Functional Food Laboratory, University of Malaya, Kuala Lumpur. Various physiological and biochemical parameters were monitored during two seasons of fruit growth between October, 2009 to August, 2010 with the 'Giant green', 'Masam manis pink' and 'Jambu madu red' cultivars of S. samarangense. Ripened fruits of the different cultivars were collected from the experimental field of Banting, Selangor and analyzed for selected physiological parameters namely chlorophyll fluorescence, quantum yield, fruit weight, total yield, number of seed per fruit, seed weight …
Role Of E-Cadherin In The Response Of Tumor Cell Aggregates To Lymphatic, Venous And Arterial Flow: Measurement Of Cell-Cell Adhesion Strength, Stephen W. Byers, Connie L. Sommers, Becky Hoxter, Arthur M. Mercurio, Aydin Tozeren
Role Of E-Cadherin In The Response Of Tumor Cell Aggregates To Lymphatic, Venous And Arterial Flow: Measurement Of Cell-Cell Adhesion Strength, Stephen W. Byers, Connie L. Sommers, Becky Hoxter, Arthur M. Mercurio, Aydin Tozeren
Arthur M. Mercurio
Defects in the expression or function of the calcium dependent cell-cell adhesion molecule E-cadherin are common in invasive, metastatic carcinomas. In the present study the response of aggregates of breast epithelial cells and breast and colon carcinoma cells to forces imposed by laminar flow in a parallel plate flow channel was examined. Although E-cadherin negative tumor cells formed cell aggregates in the presence of calcium, these were significantly more likely than E-cadherin positive cell aggregates to disaggregate in response to low shear forces, such as those found in a lymphatic vessel or venule (< 3.5 dyn/cm2). E-cadherin positive normal breast epithelial cells and E-cadherin positive breast tumor cell aggregates could not be disaggregated when exposed to shear forces in excess of those found in arteries (> 100 dyn/cm2). E-cadherin negative cancer cells …
Regulation Of Cellular Interactions With Laminin By Integrin Cytoplasmic Domains: The A And B Structural Variants Of The Alpha 6 Beta 1 Integrin Differentially Modulate The Adhesive Strength, Morphology, And Migration Of Macrophages, Leslie M. Shaw, Arthur M. Mercurio
Regulation Of Cellular Interactions With Laminin By Integrin Cytoplasmic Domains: The A And B Structural Variants Of The Alpha 6 Beta 1 Integrin Differentially Modulate The Adhesive Strength, Morphology, And Migration Of Macrophages, Leslie M. Shaw, Arthur M. Mercurio
Arthur M. Mercurio
Several integrin alpha subunits have structural variants that are identical in their extracellular and transmembrane domains but that differ in their cytoplasmic domains. The functional significance of these variants, however, is unknown. In the present study, we examined the possibility that the A and B variants of the alpha 6 beta 1 integrin laminin receptor differ in function. For this purpose, we expressed the alpha 6A and alpha 6B cDNAs, as well as a truncated alpha 6 cDNA (alpha 6-delta CYT) in which the cytoplasmic domain sequence was deleted after the GFFKR pentapeptide, in P388D1 cells, an alpha 6 deficient …
Membrane Cytoskeleton: Pip(2) Pulls The Strings, Thomas Nebl, Sang Oh, Elizabeth Luna
Membrane Cytoskeleton: Pip(2) Pulls The Strings, Thomas Nebl, Sang Oh, Elizabeth Luna
Elizabeth J. Luna
A recent application of optical tweezers has shown that plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)) levels control adhesion of the membrane bilayer to the underlying cytoskeleton, by regulated direct binding of PIP(2) to cytoskeletal proteins and/or indirect effects on cytoskeleton structure.