A cysteine proteinase in the penetration glands of the cercariae of Cotylurus cornutus (Trematoda, Strigeidae)

A cysteine proteinase from the penetration glands of Cotylurus cornutus cercariae was examined with histochemical and biochemical methods. The enzyme hydrolyzed gelatin, azocoll, azocasein, azoalbumin, N-blocked-l-arginine-4-methoxy-2-naphthylamide, and N-blocked-p-nitroanilide, but did not degrade elastin. The metal ion complexane ethylenediamine tetraacetate and the thiol-reducing compound dithioerythritol enhanced the proteinase activity, whereas the thiol-blocking compounds p-hydroxymercuribenzoate and N-ethylmaleimide (NEM) inhibited it. The enzyme was also sensitive to leupeptin but insensitive to soybean trypsin inhibitor. An electrophoretic separation of extract proteins from the cercariae under acidic, non-denaturing conditions and in the presence of 0.1% gelatin in a polyacrylamide gel revealed the presence of two distinct and three weak transparent bands in the gel resulting from a gelatinolytic activity at pH 6.8. The distinct bands apparently resulted from the activity of the glandular enzyme and lysosomal cathepsin B, whereas the weak ones presumably indicated these enzymes partially degraded in the course of the preparative procedure. No gelatinolysis occurred following treatment of an extract sample with 0.1 mM NEM

THE ISOLATION AND CULTIVATION OF LACTOBACILLUS BIFIDUS: A COMPARISON OF BRANCHED AND UNBRANCHED STRAINS

Lactobacillus bifidus ("B. bifidus") was first described, by Tissier (1899), as constituting almost the entire flora of the stools of breast-fed infants. In subse-quent publications (1905, 1906, 1908), he found that the predominating organism in the stools of bottle-fed infants was Lactobacillus acidophilus ("B. acidophilus"), which, however, was first isolated, also from nurslings ' stools, by Moro (1900). Tissier (1905) and Moro (1905) agreed that L. acidophilus was present in the feces of breast-fed infants in small numbers. Interest in the isolation and growth requirements of L. bifidus was stimulated by its apparently unique occurrence in the stools of nurslings since it was surmised that the presence of these organisms in the intestines was of physiologic significance and might prevent intestinal disorders caused by other bacteria. The original observations of Tissier concern-ing the predominance of L. bifidus in nurslings ' stools have been amply con-firmed. However, the factors responsible for the establishment and maintenance of this bacterial flora in the colon of the breast-fed infant are still unknown. As seen in smears of stools, the organisms are gram-positive, straight or curve