Show Advanced Search

REFINE YOUR SEARCH:

Containing Text
- - -
+
Filter by author or institution
GO
Filter by publication date
From:
October, 2006
Until:
Today
Filter by journal section

Filter by science education

 
 
Membrane Lipids: Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.

Membrane Fluidity

JoVE 10972

Cell membranes are composed of phospholipids, proteins, and carbohydrates loosely attached to one another through chemical interactions. Molecules are generally able to move about in the plane of the membrane, giving the membrane its flexible nature called fluidity. Two other features of the membrane contribute to membrane fluidity: the chemical structure of the phospholipids and the presence of cholesterol in the membrane. Fatty acids tails of phospholipids can be either saturated or unsaturated. Saturated fatty acids have single bonds between the hydrocarbon backbone and are saturated with the maximum number of hydrogens. These saturated tails are straight and can, therefore, pack together tightly. In contrast, unsaturated fatty acid tails contain double bonds between carbon atoms, giving them a kinked shape and preventing tight packing. Increasing the relative proportion of phospholipids with unsaturated tails results in a more fluid membrane. Organisms like bacteria and yeasts that experience environmental temperature fluctuations are able to adjust the fatty acid content of their membranes to maintain a relatively constant fluidity. In cell membranes, cholesterol is able to interact with heads of phospholipids, partly immobilizing the proximal part of the hydrocarbon chain. This interaction decreases the ability of polar molecules to cross the membrane.

 Core: Membranes and Cellular Transport

An Overview of bGDGT Biomarker Analysis for Paleoclimatology

JoVE 10256

Source: Laboratory of Jeff Salacup - University of Massachusetts Amherst


Throughout this series of videos, natural samples were extracted and purified in search of organic compounds, called biomarkers, that can relate information on climates and environments of the past. One of the samples analyzed was sediment. Sediments accumulate…

 Earth Science

Protein Associations

JoVE 10704

The cell membrane—or plasma membrane—is an ever-changing landscape. It is described as a fluid mosaic as various macromolecules are embedded in the phospholipid bilayer. Among the macromolecules are proteins. The protein content varies across cell types. For example, mitochondrial inner membranes contain ~76%, while myelin contains ~18% protein content. Individual cells contain many types ofbrane proteins—red blood cells contain over 50—and different cell types harbor distinct membrane protein sets. Membrane proteins have wide-ranging functions. For example, they can be channels or carriers that transport substances, enzymes with metabolic roles, or receptors that bind to chemical messengers. Like membrane lipids, most membrane proteins contain hydrophilic (water-loving) and hydrophobic (water-fearing) regions. The hydrophilic areas are exposed to water-containing solution inside the cell, outside the cell, or both. The hydrophobic regions face the hydrophobic tails of phospholipids within the membrane bilayer. Membrane proteins can be classified by whether they are embedded (integral) or associated with the cell membrane (peripheral). Most integral proteins are transmembrane proteins, which traverse both phospholipid layers, spanning the entire membrane. Their hydrophilic regions extend from both sides of the membrane, facing cytosol on

 Core: Membranes and Cellular Transport

Extraction of Biomarkers from Sediments - Accelerated Solvent Extraction

JoVE 10097

Source: Laboratory of Jeff Salacup - University of Massachusetts Amherst


The distribution of a group of organic biomarkers called glycerol-dialkyl glycerol-tetraethers (GDGTs), produced by a suite of archaea and bacteria, were found in modern sediments to change in a predictable manner in response to air or water temperature1,2.…

 Earth Science

The C. elegans Intestine As a Model for Intercellular Lumen Morphogenesis and In Vivo Polarized Membrane Biogenesis at the Single-cell Level: Labeling by Antibody Staining, RNAi Loss-of-function Analysis and Imaging

1Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital, Harvard Medical School, 2College of Life Sciences, Jilin University, 3Faculty of Health Sciences, University of Macau

JoVE 56100

 Developmental Biology

Spontaneous Formation and Rearrangement of Artificial Lipid Nanotube Networks as a Bottom-Up Model for Endoplasmic Reticulum

1Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, 2Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Oslo, 3Department of Chemistry and Chemical Engineering, Chalmers University of Technology

JoVE 58923

 Bioengineering

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures

1Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 2Department of Soil, Water and Environmental Science, University of Arizona, 3Department of Earth Ocean and Atmospheric Sciences, Florida State University, 4Bruker Daltonics Inc., 5Biological Sciences Division, Pacific Northwest National Laboratory

JoVE 59035

 Environment

Dissipative Microgravimetry to Study the Binding Dynamics of the Phospholipid Binding Protein Annexin A2 to Solid-supported Lipid Bilayers Using a Quartz Resonator

1Institute of Medical Biochemistry, Center for Molecular Biology of Inflammation, University of Münster, 2Institute of Biochemistry, University of Münster, 3Cluster of Excellence 'Cells in Motion', University of Münster

JoVE 58224

 Biochemistry

Capturing the Interaction Kinetics of an Ion Channel Protein with Small Molecules by the Bio-layer Interferometry Assay

1Department of General Surgery, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, 2Key Laboratory of Systems Biomedicine (Ministry of Education), Institute of Systems Biomedicine, Shanghai Jiao Tong University, 3Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiao Tong University School of Medicine

JoVE 56846

 Biochemistry

Methods to Study Lipid Alterations in Neutrophils and the Subsequent Formation of Neutrophil Extracellular Traps

1Department of Physiological Chemistry, University of Veterinary Medicine Hannover, 2Fish Disease Research Unit, University of Veterinary Medicine, 3Department of Clinical Sciences, Biomedical Center, Lund University, 4Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover

JoVE 54667

 Immunology and Infection

A Lipid Extraction and Analysis Method for Characterizing Soil Microbes in Experiments with Many Samples

1Department of Agronomy and Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, 2Department of Soil Science, University of Wisconsin - Madison, 3Department of Soil, Water, and Climate, University of Minnesota, 4Faculty of Science and Engineering, Curtin University

JoVE 55310

 Environment

Targeting Drugs to Larval Zebrafish Macrophages by Injecting Drug-Loaded Liposomes

1Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, 2School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 3School of Medicine, Faculty of Medical and Health Sciences, University of Auckland

Video Coming Soon

JoVE 60198

 JoVE In-Press
More Results...