Biochemical heterogeneity of the Sanfilippo syndrome: preliminary characterization of two deficient factors

Fibroblasts cultured from the skin of Sanfilippo patients show excessive accumulation and prolonged turnover time of sulfated mucopolysaccharide. This abnormality can be corrected by a macromolecular factor contained in the secretions of fibroblasts of differing genotype, as well as in normal human urine. By cross-correction tests, the Sanfilippo fibroblasts can be subdivided into two groups, each deficient in a different factor. Analytical polyacrylamide gel electrophoresis shows the two factors, which are probably proteins, to have a similar molecular weight (ca. 200,000) but to differ in charge at pH 8.5.     

Phloem transport of 14C-labelled assimilates in Ricinus

Summary Exudate can be obtained from incisions made in the bark of the stem of actively growing Ricinus plants. ¹⁴C-labelled assimilates from a fed leaf are rapidly detected in the exudate. This movement was both acropetal and basipetal from the fed leaf, at rates of over 100 cm h^-1. Estimated rates within intact plants were 80–84 cm h^-1.In contrast with xylem sap obtained from the same plant, the exudate obtained had an alkaline pH (8.2), a high dry matter content (10–12.5%), high sugar content (8–10%) which was predominantly sucrose; high potassium content (60–80 mM) and low calcium content (0.5–1.0 mM).It is concluded, on the basis of the present evidence, that the exudate is a true sample of the sieve tube sap undergoing translocation.     

Regulation of Newly Evolved Enzymes. I. Selection of a Novel Lactase Regulated by Lactose in ESCHERICHIA COLI

Thirty-four lactose-utilizing strains of E. coli were selected from a lac Z deletion strain. In 31 of these, the synthesis of the newly evolved lactase is regulated by lactose. The lactase activity in all the strains is indistinguishable from the ebg(+) activity identified by Campbell, Lengyel and Langridge (1973).