Luis Glaser

Cell-cell recognition

Abstract Several approaches in a variety of biological systems are being used in an attempt to understand cellular recognition at the chemical level. The precise molecular events in cell recognition have not yet been established.

A novel assay of neuronal cell adhesion.

Intact cells can be made to adhere to a glass surface which is derivitized with γ-aminopropyl-triethoxysilane, and then treated with glutaraldehyde. Such cells remain fully viable and a monolayer of such cells can be formed within 1 hour after the cells are removed from an embryo. The rate of binding of radioactively labeled single cells to such a monolayer can be used as a measure of intercellular adhesion (Walther, Ohman and Roseman, Proc. Natl. Acad. Sci. USA 70, 1569–1573 (1973). The lack of toxicity of this surface is shown by the fact that it supports normal growth of C-6 rat glial cells.

The synthesis of lipoteichoic acid carrier.

Summary Staphylococcus aureus strain H was pulse-labeled with [2- 3 H]-glycerol and then incubated in medium containing unlabeled glycerol. During the chase period radioactivity is transferred from phosphatidyl-glycerol to form the polyglycerolphosphate chain of the lipoteichoic acid carrier.

An intermediate in teichoic acid biosynthesis

Summary In the presence of UDP-N-acetyl glucosamine and CDP-glycerol a membrane preparation from Staphylococcus aureus synthesizes a lipophylic compound, which is an intermediate in the synthesis of the linkage region between teichoic acid (polyribitol phosphate) and peptidoglycan. The synthesis of this intermediate is inhibited by Tunicamycin.

Synthesis of teichoic acids: VI. The formation of multiple wall polymers in Bacillus subtilis W-23

Abstract The existence of two ribitol teichoic acids (polyribitol phosphate and glucosyl polyribitol phosphate) in the wall of Bacillus subtilis W-23 has been demonstrated by immunological means. Some of the properties of the UDP- d -glucose polyribitol phosphate glucosyl transferase of this organism have been described, and in particular it has been shown that this enzyme will use the polyribitol phosphate from the cell wall as a glucosyl acceptor. These data have suggested the presence of two distinct teichoic acid-synthesizing systems in this organism.

Cell surface-associated growth inhibitory proteins: Evidence for conservation between mouse and human cell lines☆

Abstract The ability of the normal human fibroblast line (IMR91) to exhibit density-dependent regulation of growth has been examined. The line exhibits density-dependent regulation of growth; saturation density in 15% fetal bovine serum is 2 × 10 5 cells/cm 2 . Membranes prepared from confluent monolayers of these cells contained growth inhibitory factors to both exponentially growing IMR91 and Swiss 3T3 cells. This factor(s) appears to be similar to a previously described factor found on the surface of Swiss 3T3 cells [14]. The inhibition of DNA synthesis in growing IMR91 cultures by membranes was both time- and concentration-dependent. The effect was reversible by high serum. Specificity experiments utilizing membranes prepared from Swiss 3T3 cells indicated some species specificity for inhibition by membranes, but this specificity was no longer exhibited by solubilized membrane preparations. These results are compatible with the suggestion that both the growth inhibitory factors and their receptors are conserved through evolution.

Turnover of the cell wall of bacillus subtilis W-23 during logarithmic growth☆

Abstract Extensive turnover of the mucopeptide and teichoic acid of B. subtilis W-23 occurs during logarithmic growth. The half life of the mucopeptide is of the order of 0.6 generations, while that of the teichoic acid is of the order of 2 generations, and is independent of the generation time over a four fold change in growth rate.

Nucleotide diphosphate hexose pyrophosphatases

Abstract In the course of examining several nucleotide diphosphate sugar pyrophosphorylases in extracts of E. coli and Salmonella , we noted the presence of several nucleotide diphosphate sugar pyrophosphatases. These enzymes are of interest because they are inactive in freshly prepared sonic extracts. Activity was elicited by heating the extracts at 58° for a few minutes which destroyed an inhibitor. Nucleotide diphosphate sugar pyrophosphatases may serve to prevent accumulation of nucleotide diphosphate sugars (Glaser, 1965) . In this communication we present some observations on the specificity of a few of these enzyme, their interaction with the inhibitor, and the location of the enzyme(s) and inhibitor(s) in the cell.

Developmental changes in glycoproteins of the chick nervous system

Temporal changes have been noted previously in retinal glycoproteins that bind to wheat germ agglutinin by a technique in which the denatured glycoproteins are first separated according to size by polyacrylamide gel electrophoresis, and are then localized on the gel using [125I]lectin. As reported here this technique will also detect differences between dorsal and ventral halves of the neural retina from 8-day chick embryos, and using other lectins will detect temporal changes in the glycoprotein pattern of the optic tectum. Some of the glycoproteins detected by wheat germ agglutinin in the neural retina appear to be represented on the surface of the retinal cells since: (a) the temporal changes in retinal glycoproteins can also be observed in a plasma membrane enriched fraction prepared from neural retina cells; and (b) antibodies prepared in mice against various size categories of wheat germ lectin binding glycoproteins bind to intact retinal cells.

[78] Formation of rhamnolipids of Pseudomonas aeruginosa☆

Publisher Summary This chapter discusses the synthesis of formation of rhamnolipids of Pseudomonas aeruginosa . The products of the reactions are extracted into ether after acidifying the incubation mixture. The radioactivity contained in the products is measured and used as the estimate of enzymatic synthesis. The reactions assayed by employing dTDP-L-rhamnose- 14 C as the isotope donor and either βOH-dec-βOH-decanoic acid or Rh-βOHdec-βOH-decanoic acid as the acceptor, as appropriate. The incorporation of rhamnose into either of the rhamnose-containing lipids is estimated from the radioactivity of the rhanlnolipids and the specific radioactivity of the dTDP-L-rhamnose- 14 C employed. Incorporation of unit activity is in millimicromoles of product formed per hour under the incubation conditions described above. Specific activity is expressed in millimicromoles per milligram protein or per milliliter enzyme, as appropriate, per hour. The reagents used, procedure followed, and the steps involved in the purification are also described in the chapter.