Saccharomyces cerevisiae ATCC 4126 was grown within the macroporous matrix of asymmetric-walled polysulfone hollow-fiber membranes and on the exterior surfaces of isotropic-walled polypropylene hollow-fiber membranes. Nutrients were supplied and products were removed by single-pass perfusion of the fiber lumens. Growth of yeast cells within the macrovoids of the asymmetric-walled membranes atta...

In this study, flat sheet asymmetric polyphenylsulfone (PPSU) ultrafiltration membranes with enhanced antifouling properties were prepared with a non-solvent induced phase separation (NIPS) method through compound additives containing a polymeric pore-forming agent, a small molecular non-solvent and a surfactant. The formation processes of the porous asymmetric membranes with different kinds of...

The distribution of concanavalin A (con A) receptor sites on the membranes of chromaffin granules has been investigated by binding studies using 125I-labelled con A and by electron-microscope studies using ferritin-labelled con A. In both experiments con A was observed to bind to chromaffin granule membranes but not to intact granules. The ferritin-con A particles bind to only one of the two po...

Pluronics are a class of amphiphilic triblock copolymers that are known to interact with cellular membranes in interesting ways. The solubility of these triblock copolymers in free lipid membranes can be altered with temperature, allowing the possibility of tuning their membrane insertion. However, for supported lipid membranes, the asymmetric local environment and the strong influence of the s...

Ion rejection by nanofiltration (NF) membranes with bipolar fixed charge distributions have been investigated theoretically. Salt flux rectification has been predicted as a result of the broken symmetry of the fixed charge distribution on the pore walls. The existence of an optimal volume flux (i.e. leading to the highest salt rejection) has been put in evidence when there is a region within th...

Chloroplast envelope polypeptides from spinach were separated into several fractions on the basis of their solubility in a mixture of chloroform/methanol (2:1, v/v) or in 0.1 N NaOH. Using a simple two dimension procedure for gel electrophoresis, we resolved up to 70 polypeptides. The envelope is characterized by the preponderance of high molecular weight polypeptides (Mr > 54,000), many of...