生物谷报道：弗吉尼亚州立大学(Virginia Commonwealth University)研究人员最近破译出一种人类口腔常见细菌的基因组。
血链球菌（Streptococcus sanguinis）是形成牙菌斑的多种微生物之一，通常对人体无害，但进入血液（很可能通过口腔微小伤口）后有可能引起细菌性心内膜炎（有致死性）。分析S.sanguinis的基因组有助于更好地了解其生命周期、代谢和入侵宿主、引起细菌性心内膜炎。Francis Macrina率领的研究小组发现了许多S.sanguinis细胞表面蛋白，为药物研发提供了候选靶标。
电镜下的S.sanguinis
研究结果显示，这种革兰氏阳性菌的基因组是环状DNA分子，大约由2 40万碱基对组成，比其它已测序链球菌的基因组都要大，多出DNA部分显然来自于其它细菌，编码基因赋予S.sanguinis更好应对良好口腔卫生环境的能力。
文章作者Gregory A. Buck 说，对S.sanguinis基因组测序有助于整体把握这种重要病原体的生物学特征，为弄清其致病机理开启了一扇新的大门。文章刊登于4月份Journal of Bacteriology 杂志。
部分英文原文：
Journal of Bacteriology, April 2007, p. 3166-3175, Vol. 189, No. 8
0021-9193/07/$08.00+0 doi:10.1128/JB.01808-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Genome of the Opportunistic Pathogen Streptococcus sanguinis ,
Ping Xu,1,2,3, Joao M. Alves,2,3, Todd Kitten,1,2,3 Arunsri Brown,1, Zhenming Chen,2,3,¶ Luiz S. Ozaki,2,3 Patricio Manque,2,3 Xiuchun Ge,1 Myrna G. Serrano,2,3 Daniela Puiu,2,|| Stephanie Hendricks,3 Yingping Wang,2,3 Michael D. Chaplin,2 Doruk Akan,2, Sehmi Paik,1,3, Darrell L. Peterson,4 Francis L. Macrina,1,2,3* and Gregory A. Buck2,3*
Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia 23298-0566,1 Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284-2030,2 Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia 23298-0678,3 Department of Biochemistry and Molecular Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298-06144
Received 30 November 2006/ Accepted 29 January 2007
The genome of Streptococcus sanguinis is a circular DNA molecule consisting of 2,388,435 bp and is 177 to 590 kb larger than the other 21 streptococcal genomes that have been sequenced. The G+C content of the S. sanguinis genome is 43.4%, which is considerably higher than the G+C contents of other streptococci. The genome encodes 2,274 predicted proteins, 61 tRNAs, and four rRNA operons. A 70-kb region encoding pathways for vitamin B12 biosynthesis and degradation of ethanolamine and propanediol was apparently acquired by horizontal gene transfer. The gene complement suggests new hypotheses for the pathogenesis and virulence of S. sanguinis and differs from the gene complements of other pathogenic and nonpathogenic streptococci. In particular, S. sanguinis possesses a remarkable abundance of putative surface proteins, which may permit it to be a primary colonizer of the oral cavity and agent of streptococcal endocarditis and infection in neutropenic patients.
* Corresponding author. Mailing address: Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23284-2030. Phone for Francis L. Macrina: (804) 827-2622. Fax: (804) 828-2051. E-mail: macrina@vcu.edu . Phone for Gregory A. Buck: (804) 828-2318. Fax: (804) 828-1397. E-mail: gabuck@vcu.edu
