Muscle fibers from the giant barnacle, Balanus nubilus, were placed inside the lumen of a porous glass capillary and equilibrated for 48 h in an electrolyte solution containing 2% Tween. The glass capillary prevented the chemically "skinned" fiber from swelling with a water content beyond 80%. Isotope exchange studies using 22Na, 42K, and 36Cl indicated the existence of an intermediate rate con...

A methodology is presented for calculating of the surface potential, Donnan potential, and ion concentration profiles for semipermeable microbial membranes that is valid for an arbitrary electrolyte composition. This model for surface potential, Donnan potential, and charge density was applied to recently reported experimental data for gram-positive bacteria, including Bacillus brevis, Rhodococ...

The chemical composition of the fluid surrounding the cells of the central nervous system of Periplaneta has been shown to differ from that of the haemolymph, due to a Donnan equilibrium which maintains an excess of inorganic cations in the extracellular fluid (Treherne, 1962 a, b). In view of the demonstrated permeability of the nerve sheath to ions and molecules (Treherne, 1961 a, b) it was s...

The wandering exponent u for an isotropic polymer is predicted remarkably well by a simple argument due to Flory. By considering oriented polymers living in a oneparameter farniy of background tangent fields, we are able to relate the wandering exponent to the exponent in the background field through an e-expansion. We then choose the background field to have the same correlations as the indivi...

Biologically functional liquid-liquid phase separation of intrinsically disordered proteins (IDPs) is driven by interactions encoded by their amino acid sequences. Little is currently known about the molecular recognition mechanisms for distributing different IDP sequences into various cellular membraneless compartments. Pertinent physics was addressed recently by applying random-phase-approxim...

Molecular interactions of importance to cell biology are subject to sol-gel transitions: large clusters of weakly interacting multivalent molecules (gel phase) are produced at a critical concentration of monomers. Examples include cell-cell and cell-matrix adhesions, nucleoprotein bodies, and cell signaling platforms. We use the term pleomorphic ensembles (PEs) to describe these clusters, becau...