Localization of endotoxin in the rat intestinal epithelium.

High levels of circulating lipopolysaccharide (LPS) cause intestinal inflammation and increased permeability to bacteria and toxins. To better understand the effects of LPS on the gut, confocal microscopy and immunofluorescence staining were used to examine the distribution of LPS in the rat intestine after intravenous or enteral administration. LPS was localized in macrophages in the lamina propria from 1 h to >28 days after intravenous injection.

Analysis of the F-actin binding fragments of vinculin using stopped-flow and dynamic light-scattering measurements.

Using amino acids 884-1066 and 884-1012 expressed from chicken vinculin as fusion proteins with schistosomal glutathione S-transferase, we determined the binding kinetics of the protein fragments with F-actin. We established by the stopped-flow method a two-step binding process: an initial rapid reaction followed by a slower process. The latter is attributed to F-actin cross-linking and/or bundling, which was previously detected by viscometry and electron microscopy [Johnson, R.

Inhibition of cellular proliferation by the Wilms tumor suppressor WT1 requires association with the inducible chaperone Hsp70.

The Wilms tumor suppressor WT1 encodes a zinc finger transcription factor that is expressed in glomerular podocytes during a narrow window in kidney development. By immunoprecipitation and protein microsequencing analysis, we have identified a major cellular protein associated with endogenous WT1 to be the inducible chaperone Hsp70. WT1 and Hsp70 are physically associated in embryonic rat kidney cells, in primary Wilms tumor specimens and in cultured cells with inducible expression of WT1.

Differences in F9 and 5.51 cell elasticity determined by cell poking and atomic force microscopy.

We studied the elasticity of both a wild type (F9) mouse embryonic carcinoma and a vinculin-deficient (5.51) cell line, which was produced by chemical mutagenesis. Using cell poking, we measured the effects of loss of vinculin on the elastic properties of these cells.

Differences in elasticity of vinculin-deficient F9 cells measured by magnetometry and atomic force microscopy.

We have investigated a mouse F9 embryonic carcinoma cell line, in which both vinculin genes were inactivated by homologous recombination, that exhibits defective adhesion and spreading [Coll et al. (1995) Proc. Natl.