Distribution of neuraminidase and n-acetylneuraminate lyase activities among corynebacteria, mycobacteria, and nocardias

In Corynebacterium diphtheriae and closely related neuraminidase-producing corynebacteria, we have found an N-acetylneuraminate (NAN) lyase activity which cleaves NAN into N-acetyl-d-mannosamine and, presumably, pyruvate. In vitro, these lyases can be shown to synthesize NAN. A survey of representative corynebacteria, "plant pathogenic corynebacteria," mycobacteria, and nocardias revealed that only those corynebacteria closely related to C. diphtheriae exhibited both neuraminidase and NAN lyase activities.

A case of G M2 gangliosidosis of late onset

A case of G(M2)-gangliosidosis commencing by the age of 5 years is described, in which hyperacusis, dementia, and fits were prominent clinical features. In addition to the typical ganglioside pattern on thin layer chromatography and the presence of membranous bodies in electron microscopic studies and characteristic histology and histochemistry, there was biochemical evidence of a gross reduction in heat-labile hexosaminidase activity in white blood cells and brain. A younger unaffected sibling showed the same enzyme defect in white blood cells.