Bacterial degradation of streptococcal glucans

Several strains of bacteria were isolated which have the ability to use the polyglucan polymers produced by four strains of Streptococcus mutans as a sole source of carbon and energy for growth requirements. This study shows that the enzyme system responsible for the degradation of the polyglucan is extracellular in nature.

Synthesis and degradation of hyaluronic acid in the cultured fibroblasts of Marfan's disease

Increased amounts of hyaluronic acid accumulate in fibroblasts cultured from patients with Marfan's disease, an autosomal dominant disorder. In the recessive Hurler's disease, the storage of glycosaminoglycan (GAG) is due to impaired degradation. This study examines the kinetics of GAG accumulation in Marfan's disease in order to determine whether the mechanism of accumulation differs from that in Hurler's disease.Marfan-derived fibroblasts incorporated [(14)C]acetate or [(14)C]glucosamine into GAG to a level 4-6 times greater than control fibroblasts. Sugar analyses, electrophoretic mobility, and enzyme susceptibility studies showed that the isolated material was hyaluronic acid. There were no differences in activity of a variety of glycosidases between Marfan and control fibroblasts, nor were there differences in the ability to degrade prelabeled hyaluronate by cell-free extracts. Finally, chase experiments showed parallel rates of loss of labeled GAG from control fibroblasts and fibroblasts from Marfan patients. It appears that hyaluronic acid was accumulating in greater amounts in the fibroblasts from patients with Marfan's disease because of a greater rate of synthesis as opposed to a decreased rate of breakdown.

Carbohydrates of the bovine small intestine

1. Homogenates of mucosa from bovine small intestine hydrolysed isomaltose slowly.

2. The enzyme exhibited maximum activity at pH 6·0–6·2 and possessed aKmvalue of 9·1 mM.

3. Isomaltase and maltase activities showed a similar pattern of distribution along the small intestine; activity was higher in the jejunum than in the ileum, the lowest activity being in the duodenum.

4. Neither activity changed markedly with age.

5. The disaccharidase activities (maltase, isomaltase, trehalase, lactase and cellobiase) of the small intestine were found in the sediment when homogenates were centrifuged at 100000g.

6. Heat inactivation studies suggested that there was one enzyme which hydrolysed trehalose, one enzyme which hydrolysed isomaltose, one enzyme which hydrolysed lactose and cellobiose and that the hydrolysis of maltose was brought about by more than one enzyme.

Evidence for a direct effect on articular cartilage and its lysosomal enzymes in filipin-induced arthritis

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