Two morphologic components of human amyloid deposits, the periodic rod and the fibril, have been prepared free of cross-contamination. On tryptic digestion of guanidine-denatured material, peptide maps indicate these two components to have characteristic patterns with no detectable peptide fragments in common. Additional studies on ultrastructural morphology, physical characteristics and chemical composition reveal that the two components are cleanly distinct entities Method 2 C Fibrils Periodic Rods 634 GLENNER ET AL. TABLE I Extraction Procedures for Fibrils an(l Periodic Rod Components Free of Croxs-('onta,ninaiion Extract with 0.1 M borate buffer, pH 9.5. Centrifuge at 105.000 X g, 1 hr., 0#{176}C. Repeat 5 times.

A parietal yolk sac carcinoma of the mouse that secretes large quantities of basement membrane-like material has been used to study the formation of basement membranes. Suitably characterized fluorescein-labeled antibodies against this material stained basement membranes of epithelial structures and vessels, as well as reticulin. When absorbed with reticulin and vascular basement membranes of the spleen until these structures no longer fluoresced, the antibody still stained the basement membrane-like material of the tumor, its normal embryonic counterpart (Reichert's membrane), and the basement membranes at the bases of epithelial cells. The observation made previously that parietal yolk sac cells secreted, in the absence of connective tissue and reticulin, the basement membrane (Reichert's membrane) upon which they rested has been confirmed through the localization of ferritin-labeled antibody to the endoplasmic reticulin of the secreting cells. Since a basement membrane proven to be an epithelial secretion is antigenically similar to basement membranes at the bases of all epithelial cells studied but antigenically different from connective tissue elements, it is postulated that the basement membranes at the bases of epithelial cells in general are an epithelial secretion, and are not a condensation of ground substance as is commonly believed.

Letters to the Editor HISTOCHEMICAL IDENTIFICATION OF X-ACETYL-O-DIACETYLNEURAMINIC ACID RESISTANT TO NEURAMINIDASE The histocheniical ideuitificatiots of siahic acid ut tissue secti)uis is largely l)ased oti the muse of useusranuiuuidase However, its most cases, such as rat somblimsgumal gland, this eutzyme is miot effective in destroyitig alciuiophilia amid nietachromasia (Warreii amtd Siuicer.

Stream and soil samples were screened for microorganisms that would use alginate from mucoid Pseudomonas aeruginosa as the sole carbon and energy source. A pure culture containing large aerobic rods was isolated. The cells were about 0.8 by 2.5 Fm in size, had lateral or peritrichous flagella, had a negative Gram stain reaction, and produced spores on sporulation medium. Purified DNA was approximately 46 mol% G+C as measured by thermal denaturation. From these and other biochemical tests, the organism was identified as Bacillus circulans. The enzyme activity that degraded alginate appeared in the culture medium. Upon gel filtration, alginase activity eluted as a single peak at a position corresponding to a protein of 40,000 daltons. Activity recovered from this one-step, partial purification showed apparent endomannuronidase specificity. Like other alginases previously reported, the enzyme appeared likely to be a lyase (or eliminase). However, no Bacillus species or other gram-positive bacteria have heretofore been reported to produce extracellular enzymes with alginase activity. Several other B. circulans strains from the American Type Culture Collection also appeared to have inducible extracellular alginase activity. * Corresponding author. B. circulans strain ATCC 4513 (neotype), ATCC 14175, ATCC 15518, and ATCC 15519 were obtained from the American Type Culture Collection, Rockville, Md. Mucoid clinical isolates of P. aeruginosa were obtaihed from Children's Hospital, Birmingham, Al. Enrichment of alginase-producing bacteria from soil. Soil and stream samples from Iowa, Montana, Wyoming, and Utah were placed into medium that contained 0.5% P. aeruginosa alginic acid (prepared from clinical strains by the method of Govan and Fyfe [15]), minimal salts (5), and 0.02% yeast extract. Cultures that showed turbidity and reduction in viscosity of the medium after shaking at room temperature for 1 week were subcultured and subsequently purified.