Abstract
1.
1. Bifidobacterium bifidus var. Penn, growth promoting activity of human milk and compounds derived therefrom can be expressed by a reciprocal plot, from which constants representing such activity can be derived.
2.
2. Human milk casein has microbial growth-promoting activity that apparently resides in its oligosac-charide moiety.
3.
3. Three types of oligosaccharides were demonstrated in the product of β-elimination reaction on human casein, and all had microbial growth promoting activities.
4.
4. Carbohydrate-free human casein was a competitive inhibitor of microbial growth in the presence and absence of human milk.
5.
5. Bovine milk casein and its corresponding derivatives had no effect on microbial growth.
6.
6. It is concluded that the title microorganism may possess growth promoter receptors on its surface, which can reversibly combine with carbohydrate-free human casein, and that human casein may contain a number of different oligosaccharide units.