The insolubility of Fe3+ necessitates special mechanisms for iron acquisition in most organisms. Bacteria use siderophores to chelate Fe3+ and iron in heme, hemoglobin, transferrin and lactoferrin, and employ novel mechanisms for receptor-dependent iron transport and iron-regulated gene expression. These mechanisms involve transfer of energy from the cytoplasmic membrane to the outer membrane t...

During recent years studies with isolated plasma membranes in general and transport experiments with plasma-membrane vesicles in particular (Kinne, 1976) have provided important information on the transport systems and the driving forces involved in the solute transport of the renal proximal tubule. The results of these studies are compiled in Fig. 1. In principle two driving forces can be dist...

Diffusion of binary and ternary gases through catalytic and non-catalytic membranes has been studied experimentally at atmospheric pressure. These experiments were conducted in a modified Wicke-Kallenbach diffusion cell consisting of two continuously stirred gas volumes separated by a membrane. The equipment was suitable to measure fluxes of components through the membrane in the absence of gas...

The kinetics of low density lipoprotein (LDL) cholesterol transport to the plasma membrane of Chinese hamster ovary (CHO) cells was studied. LDL was reconstituted with [3H]cholesteryl linoleate and added to CHO cells in a pulse-chase experiment. The internalization and lysosomal cleavage of reconstituted LDL (rLDL) [3H]cholesteryl linoleate to free [3H]cholesterol occurred with a half-time of 3...

We describe a cell-free system in which the membrane glycoprotein of vesicular stomatitis virus is rapidly and efficiently transported to membranes of the Golgi complex by a process resembling intracellular protein transport. Transport in vitro is energy-dependent and is accompanied by terminal glycosylation of the membrane glycoprotein (dependent upon UDP-GlcNAc and resulting in resistance to ...

background: the monoclonal antibody, c595, against breast cancer cell line was conjugated with cyclic anhydride gadolinium-diethylenetriaminepenta-acetic acid (gd-cdtpaa) to produce gd-dtpa-c595 and used as specific breast cancer cell line (mcf-7) contrast agents in magnetic resonance imaging (mri).  methods: after incubation of breast cancer cell line (mcf-7), with different contrast agents (g...

We have investigated whether cell surface changes associated with growth control and malignant transformation are linked to the cell cycle. Chicken embryo cells synchronized by double thymidine block were examined for cell-cycle-dependent alterations in membrane function (measured by transport of 2-deoxyglucose, uridine, thymidine, and mannitol), in cell surface morphology (examined by scanning...

Microtubule-based vesicle transport driven by kinesin and cytoplasmic dynein motor proteins facilitates several membrane-trafficking steps including elements of endocytosis and exocytosis in many different cell types. Most early studies on the role of microtubule-dependent vesicle transport in membrane trafficking focused either on neurons or on simple cell lines. More recently, other work has ...

The Tat (twin arginine translocation) protein transport system functions to export folded protein substrates across the bacterial cytoplasmic membrane and to insert certain integral membrane proteins into that membrane. It is entirely distinct from the Sec pathway. Here, we describe our current knowledge of the molecular features of the Tat transport system. In addition, we discuss the roles th...

Among all the models used to study membrane transport, erythrocytes (Red Blood Cells, RBCs) have probably been the most utilised cell type. Radioisotopes fluxes, isosmotic haemolysis, ion content analysis (e.g. flame photometry), or fluorescence techniques have been widely used to characterise the various transporters present in the RBCs membrane. These techniques have allowed the description o...