Role of plasma membrane lipid composition on cellular homeostasis: learning from cell line models expressing fatty acid desaturases

Experimental evidence has suggested that plasma membrane (PM)-associated signaling and hence cell metabolism and viability depend on lipid composition and organization. The aim of the present work is to develop a cell model to study the endogenous polyunsaturated fatty acids (PUFAs) effect on PM properties and analyze its influence on cholesterol (Chol) homeostasis. We have previously shown that by using a cell line over-expressing stearoyl-CoA-desaturase, membrane composition and organization coordinate cellular pathways involved in Chol efflux and cell viability by different mechanisms. Now, we expanded our studies to a cell model over-expressing both Δ5 and Δ6 desaturases, which resulted in a permanently higher PUFA content in PM. Furthermore, this cell line showed increased PM fluidity, Chol storage, and mitochondrial activity. In addition, human apolipoprotein A-I-mediated Chol removal was less efficient in these cells than in the corresponding control. Taken together, our results suggested that the cell functionality is preserved by regulating PM organization and Chol exportation and homeostasis.Fil: Jaureguiberry, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Tricerri, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Sanchez, Susana A.. University Of California At Irvine. Laboratory of Fluorescence Dynamics; Estados UnidosFil: Finarelli, Gabriela Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Montanaro, Mauro Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Prieto, Eduardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; ArgentinaFil: Rimoldi, Omar Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Bioquímicas de la Plata; Argentina. Universidad Nacional de La Plata; Argentin

A Loading Device for Fracture Testing of Compact Tension Specimen in the SEM

A loading device for performing fracture experiments on compact tension specimens in the SEM has been designed. Its key elements are a piezoelectric translator for applying controlled displacements to the loading points on the specimen and a load cell to measure applied loads. The effective transmission of displacement from the piezoelectric driver to the specimen was found to be the major mechanical design problem. The peripheral equipment includes a function generator and a high voltage amplifier that drives the piezoelectric translator as well as a video overlay and standard video equipment to record the image continuosuly during the course of the experiment. A case study on alumina describes qualitative observations on the toughening mechanism, crack-interface bridging, operating in this material. Quantitative information pertaining to the closure stresses associated with this toughening mode can be obtained by measuring the crack profile

Longitudinal Physique Changes Among Healthy White Veterans at Boston

This study presents the results of a second round of measurements taken on a group of 1813 medically screened, healthy, white veterans living in the Boston area five years after their initial measurements. The men are grouped in five year cohorts from below 30 to above 70 years of age. As we can now observe the characteristic changes with age for each five year cohort over this age range, it is possible to partition the observed cross-sectional differences in cohort averages between those differences most likely due to changes with age and those likely due to secular differences established before entrance into the study. Of the 29 measurements found to be reliable, all (save possibly chest breadth and depth) have been affected by the secular trend toward larger size, including measurements taken on the head. Changes with age are smaller in magnitude. Individual shrinkage in the vertebral column is detectable as early as the fifth decade of life. A number of measurements increase throughout life. Weight increases both longitudinally with age, and from cohort to cohort (secular trend) until the beginning of the sixth decade. There are no significant decreases in weight with old age. Men are currently gaining weight at a rate which suggests that between their middle 20’s and early 50’s, they may expect on an average to gain 8 kilograms so that the youngest current participants in the study can expect to have an average weight of about 89 kilograms by the time they are 50 years old