• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.532-534
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• 2000

The inhibitory effects of different Bifidobacterium spp. on the growth of Helicobacter pylori (HP) were investigated. A significant suppression of HP growth occurred only when HP was inoculated onto a petri dish containing 0.1 mg/ml of Bifidobacterium spp. When HP was separately cultured with B. breve K-110, B. catenulatum K-309, B magnum K-311, B. magnum K-321, and B. cuniculi K-513, the urease activity was also inhibited by these Bifidobacterium spp. Therefore, it appears that these Bifidobacterium spp. excrete a heat-labile inhibitory component for HP growth into the culture medium. Although most organic acids produced by the Bifidobacterium spp. inhibited the growth of HP, the HP growth was not inhibited by the physiological concentrations of organic acids produced in bifidobacteria-cultured media. Accordingly, these results suggest that some Bifidobacterium spp. may produce antibiotic-like compounds (bacteriocins).

• Archives of Pharmacal Research
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• v.23 no.5
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• pp.482-487
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• 2000

The antitumor activity of Bifidobacterium breve K-110, and K-I11, and B. infantis K-525 was investigated. These Bifidobacterial cells and their cell wail preparations (WPG) significantly increased the survival rate of mice who had been intraperitoneally implanted with sarcoma 180 cells. Solid tumor growth was inhibited even when the sarcoma 180 cells were implanted into the groins of the mice. However, the Bifidobacterial cells did not show in vitro cytotoxicity against tumor cell lines. Cell kinetic studies revealed that these WPGs induced neutrophils, which were followed by macrophages, at the site of peritoneal injection. The WPGs directly activated these cells to inhibit the growth of tumor cells in vitro assays. Our results suggest that Bifidobacterial WPGs induce and activate nonspecific phagocytes in situ to reject growing tumor cells in the mouse peritoneal cavity.