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Full-Text Articles in Biology

Ceramide Kinase Regulates Phospholipase C And Phosphatidylinositol 4, 5, Bisphosphate In Phototransduction, Ujjaini Dasgupta, Takeshi Bamba, Salvatore Chiantia, Pusha Karim, Ahmad N. Abou Tayoun Nov 2009

Ceramide Kinase Regulates Phospholipase C And Phosphatidylinositol 4, 5, Bisphosphate In Phototransduction, Ujjaini Dasgupta, Takeshi Bamba, Salvatore Chiantia, Pusha Karim, Ahmad N. Abou Tayoun

Dartmouth Scholarship

Phosphoinositide-specific phospholipase C (PLC) is a central effector for many biological responses regulated by G-protein-coupled receptors including Drosophila phototransduction where light sensitive channels are activated downstream of NORPA, a PLCbeta homolog. Here we show that the sphingolipid biosynthetic enzyme, ceramide kinase, is a novel regulator of PLC signaling and photoreceptor homeostasis. A mutation in ceramide kinase specifically leads to proteolysis of NORPA, consequent loss of PLC activity, and failure in light signal transduction. The mutant photoreceptors also undergo activity-dependent degeneration. Furthermore, we show that a significant increase in ceramide, resulting from lack of ceramide kinase, perturbs the membrane microenvironment of …


Manipulating Testosterone To Assess Links Between Behavior, Morphology, And Performance In The Brown Anole Anolis Sagrei, Robert M. Cox, Derek S. Stenquist, Justin P. Henningsen, Ryan Calsbeek Aug 2009

Manipulating Testosterone To Assess Links Between Behavior, Morphology, And Performance In The Brown Anole Anolis Sagrei, Robert M. Cox, Derek S. Stenquist, Justin P. Henningsen, Ryan Calsbeek

Dartmouth Scholarship

Survival and reproductive success are determined by the complex interplay between behavior, physiology, morphology, and performance. When optimal trait combinations along these various phenotypic axes differ between sexes or across seasons, regulatory mechanisms such as sex steroids can often facilitate sex‐specific and/or seasonal trait expression. In this study, we used surgical castration and replacement of exogenous testosterone in adult male brown anoles (Anolis sagrei) to simultaneously examine the effects of testosterone on a suite of morphological (dewlap area, body size), physiological (immune function), behavioral (dewlap, head bob, and push‐up displays), and performance (stamina, sprint speed, bite force) traits. …