生物谷報(bào)道：英國(guó)諾丁漢大學(xué)科學(xué)家在最新一期《基因組研究》雜志上發(fā)表報(bào)告說(shuō),，他們成功地對(duì)肉毒桿菌的基因組進(jìn)行了測(cè)序,。肉毒桿菌可產(chǎn)生致命毒素,，因此破譯它的基因組將有助于更好地了解和利用這種特殊細(xì)菌,。
據(jù)美國(guó)科學(xué)促進(jìn)會(huì)網(wǎng)站２５日?qǐng)?bào)道，諾丁漢大學(xué)的基因組測(cè)序小組介紹,，通常情況下,，肉毒桿菌都處于休眠孢子狀態(tài)，或者在土壤里的動(dòng)物腐尸中“謀生”,。它會(huì)伺機(jī)而動(dòng),，通過(guò)受污染的食物或外部傷口，進(jìn)入活體動(dòng)物體內(nèi),，引發(fā)宿主中毒甚至致命,。
研究小組說(shuō)，肉毒桿菌的獨(dú)特之處就在于,，在環(huán)境不宜時(shí)它可以處于冬眠狀態(tài)“休養(yǎng)生息”,，一旦成功進(jìn)入活體動(dòng)物體內(nèi)，肉毒桿菌立即激活,，猛烈攻擊宿主,。攻下一個(gè)宿主之后，肉毒桿菌便以此為新的冬眠環(huán)境,，耐心等待下一次機(jī)會(huì),。研究人員稱(chēng)，肉毒桿菌的這種生存機(jī)制與大多數(shù)細(xì)菌迥然不同,，“是另一種極端的機(jī)會(huì)主義生存方式”,。
肉毒桿菌的基因組十分穩(wěn)定，屬“梭狀芽孢桿菌屬”,。與“梭狀芽孢桿菌屬”其他５種已破譯基因組的細(xì)菌相比,，肉毒桿菌僅有１６％的基因是與其他５種共有的，而４３％的基因都是肉毒桿菌所特有的,。
肉毒桿菌本身通常又可細(xì)分為幾個(gè)不同變種,，但實(shí)際上肉毒桿菌不同變種之間的差異也頗大，唯一的共性就是它們都能分泌致命毒素,。這種毒素可以破壞神經(jīng)功能,，因此在醫(yī)學(xué)領(lǐng)域用于治療眼瞼及面肌痙攣，美容領(lǐng)域還用它來(lái)除皺,。
原始出處:
Published online before print May 22, 2007
Genome Research, DOI: 10.1101/gr.6282807
Letter
Genome sequence of a proteolytic (Group I) Clostridium botulinum strain Hall A and comparative analysis of the clostridial genomes
Mohammed Sebaihia1, Michael W. Peck2, Nigel P. Minton3, Nicholas R. Thomson1, Matthew T.G. Holden1, Wilfrid J. Mitchell4, Andrew T. Carter2, Stephen D. Bentley1, David R. Mason2, Lisa Crossman1, Catherine J. Paul5, Alasdair Ivens1, Marjon H.J. Wells-Bennik2, Ian J. Davis3, Ana M. Cerdeño-Tárraga1, Carol Churcher1, Michael A. Quail1, Tracey Chillingworth1, Theresa Feltwell1, Audrey Fraser1, Ian Goodhead1, Zahra Hance1, Kay Jagels1, Natasha Larke1, Mark Maddison1, Sharon Moule1, Karen Mungall1, Halina Norbertczak1, Ester Rabbinowitsch1, Mandy Sanders1, Mark Simmonds1, Brian White1, Sally Whithead1, and Julian Parkhill1,6
1 Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, United Kingdom; 2 Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, United Kingdom; 3 Centre for Biomolecular Sciences, Institute of Infection, Immunity and Inflammation, School of Molecular Medical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom; 4 School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, United Kingdom; 5 Bureau of Microbial Hazards, Health Canada, Ottawa, Ontario, K1A 0L2, Canada
Abstract
Clostridium botulinum is a heterogeneous Gram-positive species that comprises four genetically and physiologically distinct groups of bacteria that share the ability to produce botulinum neurotoxin, the most poisonous toxin known to man, and the causative agent of botulism, a severe disease of humans and animals. We report here the complete genome sequence of a representative of Group I (proteolytic) C. botulinum (strain Hall A, ATCC 3502). The genome consists of a chromosome (3,886,916 bp) and a plasmid (16,344 bp), which carry 3650 and 19 predicted genes, respectively. Consistent with the proteolytic phenotype of this strain, the genome harbors a large number of genes encoding secreted proteases and enzymes involved in uptake and metabolism of amino acids. The genome also reveals a hitherto unknown ability of C. botulinum to degrade chitin. There is a significant lack of recently acquired DNA, indicating a stable genomic content, in strong contrast to the fluid genome of Clostridium difficile, which can form longer-term relationships with its host. Overall, the genome indicates that C. botulinum is adapted to a saprophytic lifestyle both in soil and aquatic environments. This pathogen relies on its toxin to rapidly kill a wide range of prey species, and to gain access to nutrient sources, it releases a large number of extracellular enzymes to soften and destroy rotting or decayed tissues
Corresponding author.
E-mail [email protected] ; fax 44-1223-494919.
