Journal of Intestinal Microbiology
Online ISSN : 1349-8363
Print ISSN : 1343-0882
ISSN-L : 1343-0882
Volume 25, Issue 4
Displaying 1-4 of 4 articles from this issue
  • Kyoko TAKAHASHI
    2011 Volume 25 Issue 4 Pages 213-219
    Published: 2011
    Released on J-STAGE: November 16, 2011
    JOURNAL FREE ACCESS
    A huge number of commensal bacteria inhabit the intestinal tract. Although these bacteria are not immunological “self” to the host, the intestinal immune system, the largest immune system in the body, does not exclude them completely, resulting in a symbiotic relationship. Since the vast area of intestinal mucosa is covered by a single layer of intestinal epithelial cells (IECs), IECs are continually exposed to the luminal bacteria. IECs not only physically separate the luminal contents from the internal milieu but also actively participate in induction or conditioning of intestinal immune reactions. In this review, the regulation of the epithelial barrier and immune reactions by the crosstalk between IECs and commensal bacteria as well as the expression and function of microbe recognition molecules in IECs as a basis of the crosstalk are discussed.
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  • Jiro NAKAYAMA
    2011 Volume 25 Issue 4 Pages 221-234
    Published: 2011
    Released on J-STAGE: November 16, 2011
    JOURNAL FREE ACCESS
    Recent progress in microbiology has shed light on the importance of cell-to-cell communication in bacteria, which organizes and reinforces bacterial communities consisting of single-celled organisms. Bacteria often use chemical compound as a communication signal. Quorum sensing is the best-studied phenomenon for cell-to-cell communication in bacteria, in which a cell senses the outside concentration of autoinducer to recognize the cell density of the same species/strain and consequently turns on or off the expression of certain genes. In this review, cell-to-cell chemical communications in Gram-negative and Gram-positive bacteria and their signal transduction mechanisms are overviewed.
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  • Yoshiyuki GOTO, Hiroshi KIYONO
    2011 Volume 25 Issue 4 Pages 235-243
    Published: 2011
    Released on J-STAGE: November 16, 2011
    JOURNAL FREE ACCESS
    The research on intestinal microbiota has recently accelerated and expanded with the development of the sequencing and mass spectrometric technologies such as metagenomic and metabolomic analyses. As the research on the elucidation of crosstalk between intestinal microbiota and mucosal immune system progresses, it has become clear that the immune effector molecules such as secretory IgA (SIgA) antibodies have important roles in the creation and maintenance of the unique homeostasis between intestinal microbiota and host intestinal tissues via so called physiological inflammation. To this end, T helper cell subsets with an opposite regulatory functions of activation and inhibition are induced and maintained by intestinal microbiota for the development of physiological inflammatory state in the intestine. This physiological inflammation is tightly controlled by the crosstalk between intestinal microbiota and mucosal immune systems, thereby disruption of this homeostasis leads to the onset of immune diseases including inflammatory bowel disease. Further studies about the molecular and cellular mechanisms of the homeostasis of intestinal microflora and the mucosal immune system should provide the important basic information for the development of the innovative treatment of these undesired diseases as well as contribute to the developmental strategy of mucosal vaccine such as oral vaccine as a new generation vaccine for the control of emerging and re-emerging infectious diseases.
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  • Kazuhiro HIRAYAMA, Kikuji ITOH
    2011 Volume 25 Issue 4 Pages 245-250
    Published: 2011
    Released on J-STAGE: November 16, 2011
    JOURNAL FREE ACCESS
    Although it is well known that our intestinal microbiota plays an important role in health and disease, it is often difficult to study the precise role of the human intestinal microbiota. This is largely due to the difficulties of studying the human intestinal microbiota, e.g., its very complex composition, huge number of constituents, active metabolic activities, the very special conditions in our intestinal tract including its strict anaerobic condition and low redox potential. It is also difficult to study the human intestinal microbiota in humans due to the difficulties in controlling genetic, environmental and dietary conditions of humans and due to ethical problems associated with utilizing pathogens, carcinogens or toxic substances in human volunteers. Thus, studying our intestinal microbiota requires special techniques. In this review, examples of in vitro and in vivo models to study the ecology and roles of human intestinal microbiota and their advantages and disadvantages are discussed.
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