日本研究人员在新一期《科学》杂志网络版发表的研究结果显示,幽门螺杆菌等病原菌和乳酸菌等益生菌合成呼吸所需维生素的机制完全不同。
日本富山县立大学副教授大利彻等人介绍说,他们解析了多种微生物的基因组后新发现了病原菌共有的4个基因,这些基因的功能都是编码合成病原菌呼吸所需的维生素。研究人员进一步分析了这4个基因,并将病原菌和益生菌合成呼吸所需维生素的过程进行了对比。结果发现,虽然病原菌和益生菌合成维生素所用的原料相同,但这些原料经过完全不同的化学变化,最终形成了维生素。
幽门螺杆菌与胃癌等的发病密切相关,目前针对幽门螺杆菌的除菌药物会把肠道内对人体有益的益生菌一道杀灭,有引发腹泻、腹痛等副作用。研究人员说,以新发现为基础,将来也许可以通过基因操作除去病原菌,同时又不“误杀”益生菌。(生物谷Bioon.com)
生物谷推荐原始出处:
Science 19 September 2008: Vol. 321. no. 5896, pp. 1670 - 1673 DOI: 10.1126/science.1160446
An Alternative Menaquinone Biosynthetic Pathway Operating in Microorganisms
Tomoshige Hiratsuka,1 Kazuo Furihata,2 Jun Ishikawa,3 Haruyuki Yamashita,4 Nobuya Itoh,1 Haruo Seto,5Tohru Dairi1*
In microorganisms, menaquinone is an obligatory component of the electron-transfer pathway. It is derived from chorismate by seven enzymes in Escherichia coli. However, a bioinformatic analysis of whole genome sequences has suggested that some microorganisms, including pathogenic species such as Helicobacter pylori andCampylobacter jejuni, do not have orthologs of the men genes, even though they synthesize menaquinone. We deduced the outline of this alternative pathway in a nonpathogenic strain of Streptomyces by bioinformatic screening, gene knockouts, shotgun cloning with isolated mutants, and in vitro studies with recombinant enzymes. As humans and commensal intestinal bacteria, including lactobacilli, lack this pathway, it represents an attractive target for the development of chemotherapeutics.
1 Biotechnology Research Center, Toyama Prefectural University, Toyama 939-0398, Japan.
2 Division of Agriculture and Agricultural Life Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657 Japan.
3 Department of Bioactive Molecules, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-8640, Japan.
4 Advanced Materials Research and Development Laboratory, ADEKA Corporation, Arakawa-ku, Tokyo 116-8553, Japan.
5 Faculty of Applied Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan.