Antibacterial effects of catechins, the major green tea polyphenols, were studied using Clostridium and Bacillus spores. Incubation with crude catechins decreased the number of C botulinum and C butyricum spores but not B cereus spores. Furthermore, the effects of six catechin derivatives on spores were investigated. (−)-Epicatechin gallate (ECg), (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCg) and (+)-gallocatechin gallate (GCg) were more effective in decreasing C botulinum and C butyricum spore numbers than (+)-catechin (C) and (−)-epicatechin (EC). The vegetative growth of C botulinum and B cereus was inhibited by crude extracts of the catechins. Specifically, purified GCg and EGCg inhibited the vegetative growth of C botulinum and B cereus. The inhibitory effect of ECg on B cereus was similar to that of GCg. However, toxin-production by B cereus was not inhibited by catechin. Damage to the membrane of C butyricum spores by catechin derivatives was shown using fluorescent microscopy. This study shows that low concentrations of catechins, although requiring a long exposure time, inhibited the growth of bacterial spores. However, the effects of the purified derivatives of the catechins were not the same and GCg and EGCg were found to be the most potent. Spores that are generally resistant to many disinfectants were sensitive to catechins.

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Functional maturation of the small intestine occurs during the weaning period in rats. It is known that this development is facilitated by glucocorticoid. However, the effect of glucocorticoid on morphological development of small intestine has yet to be clarified. The present study evaluated the morphological development and cell proliferation of the small intestine in adrenalectomized (ADX) rat pups. To further understand the mechanism of glucocorticoid effects on intestinal development, we examined the localization of the glucocorticoid receptor in the small intestine. Microscopic analysis showed that growth of villi and crypts is agedependent, and is significantly attenuated in ADX rats compared with sham-operated rats. BrdU-positive cells, i.e. proliferating cells, were primarily observed in crypt compartments and rapidly increased in number during the early weaning period. The increase in BrdUpositive cells could be attenuated by adrenalectomy. The morphological development of small intestine may be associated with increased proliferation of epithelial cells. On the other hand, glucocorticoid receptors were found in epithelial cells of the mid-and lower villi and not in crypts where BrdU-positive cells were localized. These results indicate that the growth of small intestine is attenuated by adrenalectomy, and that glucocorticoid indirectly acts on proliferation of epithelial cells during the weaning period.

A respiration burst of rice leaf tissue slices infected by compatible blast fungus race with or without the application of probenazole or incompatible blast fungus race, or stimulated by one of the hyphal components was quantitatively analysed. A time at maximum rate of the augmentation phase and a half life time of the auto-inactivation phase were respectively determined. A time-sequential orderliness along either line of the time of maximum rate or the half life time was observed. A high correlation coefficient between the values of time of maximum rate and half life time was also observed. By the application of probenazole, both the time of maximum rate and half life time of respiration burst were shifted as in an incompatible combination even in a compatible infection. Superoxide anion and hydrogen peroxide generation were also observed when glucose was used as a respiratory substrate. The major oxidative product of glucose seemed to be gluconate.