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The choline-containing teichoic acids of pneumococci can be modified by biosynthetic replacement of the choline residues with certain structural analogues, such as ethanolamine (EA) or the N-monomethyl-(MEA) and N-dimethyl-(DEA) amino derivatives of ethanolamine. Cells containing such analogues in their teichoic acids develop pleiomorphic alterations in several physiological properties, which include resistance to detergent-induced lysis and inhibition of cell separation (chain formation). We report here the results of physiological studies on the mechanism of these two phenomena. Our results are summarized in the following: (a) Pneumococci grown on various amino alcohols produce cell walls of identical amino sugar and amino acid composition. (b) Both choline- and EA-containing teichoic acids seem to follow the same conservative pattern of segregation during growth and cell division.(c)Lysis sensitivity of pneumococci requires the juxtaposition oflysissensitive (choline-containing) cell walls and endogenous autolysin at the cell wall growth zone. (d) Upon readdition of choline to ethanolamine-containing cells, lysis sensitivity and catalytically active (C-type) autolysin reappear in the bacteria with the same kinetics. (e) The chains of EA-grown pneumococci contain fully compartmentalized cells and normal cross walls.

Variant clones of B16 melanoma cells have been isolated that detached from plastic tissue culture dishes either more or less readily than the parent line upon treatment with EDTA or ethyleneglycol-bis(b-amino ethyl ether)N,N'-tetraacetic acid. Cells that detached more readily were spindlier in culture than parent cells, covered less surface area per cell, and formed fewer pulmonary tumors when injected iv into C57BL/6J mice. Cells that detached less readily were flatter in culture and formed more pulmonary tumors when injected iv than the parent cells. After detachment with EDTA, the cells reattached to culture dishes at the same rate.

ABSTRACT/3-Galactoside-binding lectins were isolated from various calf tissues and from chicken hearts by affinity chromatography on asialofetuin-Sepharose, and were compared with respect to biochemical characteristics, binding properties, antigenic cross-reactivity, and cellular localization. The lectins are all thiol grouprequiring, divalent cation-independent dimers, of apparent monomer mol wt 12,000 (calf lectins) or 13,000 (chicken lectin), and acidic pI. The calf lectins appear essentially identical by dodecyl sulfate-polyacrylamide gel electrophoresis, isoelectric focusing, amino acid composition, and radioimmunoassay, while the chicken lectin is distinctly different by these criteria. However, all of the lectins competed for the same binding sites on rabbit erythrocytes, and could be inhibited by the same saccharide haptens (notably lactose and thiodigalactoside). Immunofluorescence studies on several cultured cell lines revealed that the bovine and chicken lectins had primarily an intracellular cytoplasmic localization. The galactoside-binding lectins of vertebrates appear to be species-specific rather than tissue-specific.KEY WORDS lectins vertebrate lectins /3-galactoside-binding lectins affinity chromatographyAlthough lectins from various plant and invertebrate sources have been known for many years (for a comprehensive list, see reference 23), their presence in vertebrate tissues has been investigated only recently. Ashwell and Morell (3) have described a hepatic binding protein which has been implicated in the clearance of glycoproteins from plasma; in mammals, this binding protein is a fl-galactoside-specific, integral membrane protein of large molecular weight, which can be solubilized by detergents but not by hapten saccharides and which requires divalent cations for binding activity. Subsequently, hepatic and reticuloendothelial cell-binding proteins which recognize mannose, N-acetylglucosamine, and fucose have been detected (1,4,6,8,18,20,29,31,32). A "lectin" from platelet plasma membranes has been described by Gartner et al. (16) which is inhibitable by free amino sugars and amino acids; the large external transformation-sensitive (LETS) protein or fibronectin also agglutinates erythrocytes and is inhibitable by amines (35). In addition to these membrane-bound lectins, several J. CELL BIOLOGY 9 The Rockefeller University Press 9