Evidence for the association of villin with core filaments and rootlets of intestinal epithelial microvilli

Villin, a 95,000 dalton polypeptide of intestinal brush border which is known to bundle or sever actin filaments in a Ca++-dependent manner, was localized in rat and chicken intestinal epithelium by means of immunocytochemistry at the light- and electron-microscopic levels. Specific antibodies to villin were raised in rabbits immunized with villin purified from chicken intestinal epithelium. Anti-villin bound selectively to the microvillus filament bundle from its tip down to the rootlets. These findings indicate that the well-known stability of rootlet filaments towards elevated Ca++ ion concentrations cannot be explained by the absence of villin. Therefore additional factors must exist which prevent the rootlets from Ca++-villin mediated disassembly.     

Characteristics of films prepared from native and modified branched β-1,3- -glucans

The properties of films prepared from a high molecular weight (mol. wt: 7·5 × 10⁶ g/mol) branched β-1,3- -glucan (schizophyllan) and a polyalcohol (mol. wt: 7·3 × 10⁶ g/mol) derived from schizophyllan by periodate oxidation and subsequent borohydride reduction are described. The films can only be prepared by casting from aqueous solutions, because the polymers are not thermoplastic. They have a low permeability to oxygen, but a high permeability to water vapour. The tensile strength of the films is 45–58 N/mm⁻² for schizophyllan and 12–18 N/mm² for the polyalcohol, and both, but especially the polyalcohol films, have a low elongation at break. Films prepared from both polymers, under conditions where the triple helices are disrupted (>0·01 NaOH), show lower tensile strength and elongations at break as well as higher oxygen permeabilities. A relationship exists between the water content of the films and the tensile strength.     

A new species ofPalaeospinax (Chondrichthyes,Neoselachii) from the Lower JurassicPosidonia Shale of Southern Germany

The diagnosis of the fossil neoselachian genusPalaeospinax Egerton 1872 is revised. A new species from the Lower ToarcianPosidonia Shale of Southern Germany is described asPalaeospinax politus n. sp. It differs from all other known members of the genus in having smooth anterior and lateral teeth.     

Expression and subcellular location of native and mutant hTNFα proteins in Escheriahia coli

Abstract Several mutant hTNFα genes were constructed by deletion and stepwise reconstitution of regions coding for C-terminal sequences. The mutant hTNFα proteins behaved differently from native hTNFα when expressed in Escherichia coli . They were either sensitive to proteolytic degradation or formed insoluble aggregates depending on the strains and conditions used for expression. By contrast, native hTNFα was always present in a soluble form and had a tendency to associate with the cytoplasmic membrane. It was even transported to the periplasmic space in E. coli as shown by both cell fractionation and immunoelectron microscopy. The different behaviour of mutant hTNFα proteins probably results from a disturbance of protein folding.     

Red Food Coloring Stain: New,Safer Procedures for Staining Nematodes in Roots and Egg Masses on Root Surfaces

Acid fuchsin and phloxine B are commonly used to stain plant-parasitic nematodes in roots and egg masses on root surfaces, respectively. Both stains can be harmful to both the user and the environment and require costly waste disposal procedures. We developed safer methods to replace both stains using McCormick Schilling red food color. Eggs, juveniles, and adults of Meloidogyne incognita stained in roots with red food color were equally as visible as those stained with acid fuchsin. Egg masses stained with red food color appeared as bright-red spheres on the root surfaces and were highly visible even without magnification. Replacement of acid fuchsin and phloxine B with red food color for staining nematodes is safer for the user and the environment, and eliminates costly waste disposal of used stain solutions.