Hartree and Thomas: the forefathers of density functional theory

Douglas Hartree and Hilleth Thomas were graduate students together at Cambridge University in the mid-1920s. Each developed an important approximation method to calculate the electronic structure of atoms. Each went on to make significant contributions to numerical analysis and to the development of scientific computing. Their early efforts were fused in the mid-1960s with the development of an approach to the many-particle problem in quantum mechanics called density functional theory. This paper discusses the experiences which led Hartree and Thomas to their approximations, outlines the similarities in their subsequent careers, and highlights the essential role their work played in the foundational papers of modern density functional theory.     

Lysosomal membrane fragility and catabolism of cytosolic proteins: evidence for a direct relationship

Summary A direct relationship was established between the stability of the lysosomal membrane and an estimate of cytosolic protein catabolism, based on loss of radiolabel from prelabeled protein. Lysosomes in the lysosomally-rich digestive cells of the midgut gland of the marine mussel (Mytilus edulis) were destabilized by experimental treatment with phenanthrene.     

Lysosomal membrane fragility and catabolism of cytosolic proteins: evidence for a direct relationship

A direct relationship was established between the stability of the lysosomal membrane and an estimate of cytosolic protein catabolism, based on loss of radiolabel from prelabeled protein. Lysosomes in the lysosomally-rich digestive cells of the midgut gland of the marine mussel (Mytilus edulis) were destabilized by experimental treatment with phenanthrene.     

Spontaneous junctional currents in Drosophila muscle fibres: effects of temperature, membrane potential and ethanol.

Fast, slow and fast multiquantal spontaneous junctional currents were recorded from glutamate sensitive muscle fibres of Drosophila larvae. Decrease of temperature and hyperpolarization prolonged the time course of fast currents. Ethanol (0.4 M) markedly shortened their duration, whereas several other drugs known to modify the time course of currents at cholinergic synapses were ineffective at this neuromuscular junction.     

The effects of ethanol on embryonic actin: a possible role in teratogenesis

When the neural crest is cultured in the long or short term presence of ethanol, monoclonal anti-actin reveals the development of a disorganized actin cytoskeleton. In the long term, many cells fail to differentiate morphologically, whereas in the short term already differentiated cells rapidly alter their shape and their cell-to-cell contacts.     

Dantrolene: evidence for effects on Na permeability properties of the nodal membrane

The effects of dantrolene on myelinated frog nerve fibers were studied in voltage clamp experiments. Dantrolene shifted the potential-dependent parameters describing Na+ permeability towards more negative membrane potentials. The findings are interpreted as a change in the negative surface charge of the membrane.     

Newton–Cartan theory and teleparallel gravity: The force of a formulation

It is well-known that Newtonian gravity, commonly held to describe a gravitational force, can be recast in a form that incorporates gravity into the geometry of the theory: Newton–Cartan theory. It is less well-known that general relativity, a geometrical theory of gravity, can be reformulated in such a way that it resembles a force theory of gravity; teleparallel gravity does just this. This raises questions. One of these concerns theoretical underdetermination. I argue that these theories do not, in fact, represent cases of worrying underdetermination. On close examination, the alternative formulations are best interpreted as postulating the same spacetime ontology. In accepting this, we see that the ontological commitments of these theories cannot be directly deduced from their mathematical form. The spacetime geometry involved in a gravitational theory is not a straightforward consequence of anything internal to that theory as a theory of gravity. Rather, it essentially relies on the rest of nature (the non-gravitational interactions) conspiring to choose the appropriate set of inertial frames.     

Morphological evidence of a polypeptide-like secretory function of the B cells in the mouse synovial membrane

Summary In the synovial membrane of the mouse, morphological features associated with acitve secretion are unusually well developed in cells immediately subjacent to the lining layer (in the position of B cells), comparable to those of cells known to elaborate polypeptides.This work was supported by grant No 74.1.133.4, Institut National de la Santé et de la Recherche Médicale, France.     

The preprotein translocase of the outer mitochondrial membrane: receptors and a general import pore

Cytosol-synthesized preproteins destined for the mitochondria are transported across the outer membrane by the translocase of the mitochondrial outer membrane (TOM complex). This dynamic transport machinery can be divided into receptors that recognize preprotein targeting signals and components of the general import pore complex that mediate preprotein transport across the outer membrane. This review focuses on recent studies dealing with the central questions regarding the pore-forming subunits, and architecture and gating of the translocation channel of the outer membrane.     

Identification of organ-specific glycosylation of a membrane protein in two tissues using lectins

Since glycosylation of proteins is performed by the host cell, and variable sugar groupings can confer heterogeneity on the same polypeptide, we wished to see whether membrane proteins, in particular the ubiquitous transmembrane Na, K-ATPase, could be glycosylated differently in different organs. Using a highly sensitive enzyme-linked antibody detection system of bound digoxigenin-labelled lectins on nitrocellulose sheets containing electroblotted and subunits of kidney and brain Na,K-ATPase, isolated from various rat strains, in combination with isoform-specific immunoblots, we discovered that brain Na,K-ATPase was highly mannosylated in contrast to renal Na,K-ATPase. Thus, we describe the existence of organ-related glycoforms of an integral ubiquitous membrane protein, i.e. diversification of the same polypeptide by organ-typical sugars. At the same time, the presence of the same glycosylation pattern can make distinct protein isoforms occurring in a same organ more homogeneous. Such organ-related glycoforms may serve for tissue identification and as tissue-specific receptors.