Bioscience of Microbiota, Food and Health
Online ISSN : 2186-3342
ISSN-L : 2186-3342
31 巻 , 2 号
選択された号の論文の4件中1~4を表示しています
Review
  • Satoru FUKIYA, Yosuke HIRAYAMA, Mikiyasu SAKANAKA, Yasunobu KANO, Atsu ...
    原稿種別: Review
    2012 年 31 巻 2 号 p. 15-25
    発行日: 2012年
    公開日: 2012/04/20
    ジャーナル フリー
    Bifidobacteria are well known as beneficial intestinal bacteria that exert health-promoting effects in humans. In addition to physiological and immunological investigations, molecular genetic technologies have been developed and have recently started to be applied to clarify the molecular bases of host-Bifidobacterium interactions. These technologies include transformation technologies and Escherichia coli-Bifidobacterium shuttle vectors that enable heterologous gene expression. In this context, a plasmid artificial modification method that protects the introduced plasmid from the restriction system in host bifidobacteria has recently been developed to increase transformation efficiency. On the other hand, targeted gene inactivation systems, which are vital for functional genomics, seemed far from being practically applicable in bifidobacteria. However, remarkable progress in this technology has recently been achieved, enabling functional genomics in bifidobacteria. Integrated use of these molecular genetic technologies with omics-based analyses will surely boost characterization of the molecular basis underlying beneficial effects of bifidobacteria. Applications of recombinant bifidobacteria to medical treatments have also progressed.
Full Paper
  • Taeko HAYASHI, Shuhei UEDA, Hiroki TSURUTA, Hiroshige KUWAHARA, Ro OSA ...
    原稿種別: Full Paper
    2012 年 31 巻 2 号 p. 27-36
    発行日: 2012年
    公開日: 2012/04/20
    ジャーナル フリー
    Complexing of green tea catechins with food constituents and their hydrolysis by tannase-producing Lactobacillus plantarum strains, were investigated. Our observations indicated that 1) epigallocatechin gallate (EGCg) and other catechin galloyl esters bound with food ingredients (i.e., proteins) to form a complex that is likely to be unabsorbable through the intestinal wall, whereas most catechins not esterified with gallic acid (GA) remain in free form, not complexing with food ingredients; 2) tannase activity of L. plantarum is strain dependent, possibly grouped into those with high tannase activity hydrolyzing EGCg to epigallocatechin and GA and those with the low activity; and 3) L. plantarum strains with high tannase activity are capable of hydrolyzing not only intact EGCg but also EGCg and other catechin galloyl esters complexed with dietary proteins to free non-galloyl ester catechins and GA. The evidence suggests that L. plantarum with high tannase activity, if it colonizes the human intestine, would release free non-galloyl-ester catechins and GA that are readily absorbed through the human intestinal epithelia from the complexes, thereby ensuring maximum delivery of the bioactive polyphenols of green tea to the host.
  • Takashi NAKAMURA, Taizo NAGURA, Katsuyuki SATO, Masao OHNISHI
    原稿種別: Full Paper
    2012 年 31 巻 2 号 p. 37-45
    発行日: 2012年
    公開日: 2012/04/20
    ジャーナル フリー
    Poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) is the most common organic germanium compound. The ingestion of Ge-132 promotes bile secretion. We assessed the rat caecal characteristics after the administration of Ge-132 and raffinose, a prebiotic oligosaccharide, because both Ge-132 and some prebiotics can change the fecal color to yellow. We also compared the changes in the caecal flora caused by the two compounds. In addition, we evaluated the simultaneous administration of Ge-132 and raffinose and their effects on β-glucuronidase activity, which is known to be a factor related to colon cancer. Male Wistar rats (three weeks old) were given one of the following diets: 1) a control diet (control group), 2) a diet containing 0.05% Ge-132 (Ge-132 group), 3) a diet containing 5% raffinose (RAF group) or 4) a diet containing 0.05% Ge-132 + 5% raffinose (GeRAF group). The Bifidobacterium, Lactobacillus and total bacteria counts were significantly increased by the dietary raffinose, and Ge-132 did not suppress this increase. The raffinose intake increased caecal acetic acid production significantly. The activity of β-glucuronidase in the caecal contents was increased by dietary Ge-132, whereas dietary raffinose decreased the β-glucuronidase activity significantly. These results indicate that the simultaneous intake of dietary raffinose and Ge-132 does not inhibit the effects of either compound on intestinal fermentation and bile secretion. Additionally, the simultaneous intake of both raffinose and Ge-132 could abrogate the increase in β-glucuronidase activity induced by Ge-132 alone.
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