法國科學(xué)家在最新一期英國《自然》（Nature）雜志上發(fā)表報(bào)告說，他們在單細(xì)胞生物阿米巴變形蟲體內(nèi)發(fā)現(xiàn)了兩種新型病毒，其中一種體積“巨大”，堪稱目前世界上最大的病毒。
法國國家科研中心微生物專家伯納德·拉斯科拉和迪迪埃·拉烏爾在報(bào)告中說,，兩種新型病毒都是在寄生于空調(diào)系統(tǒng)冷卻水管道里的阿米巴變形蟲體內(nèi)發(fā)現(xiàn)的。其中一種名叫Mimivirus,，比一般病毒大出很多,，體積幾乎與小型細(xì)菌相仿，用普通顯微鏡就能夠觀察到它的存在,。而且它的“塊頭”甚至超過了現(xiàn)在世界上已知的最大病毒——巨病毒,，后者在2003年有關(guān)軍團(tuán)病的研究中被發(fā)現(xiàn),，也寄生在水生阿米巴變形蟲體內(nèi)。
拉斯科拉表示,，巨病毒比Mimivirus略小,，但兩種病毒都屬于同一家族。
科學(xué)家發(fā)現(xiàn)的另一種病毒叫作Sputnik,。據(jù)拉斯科拉介紹,，該病毒依附在Mimivirus身上，有21個(gè)基因,，它能夠破壞宿主Mimivirus的繁殖能力,。
科學(xué)家指出，這些病毒通常都存在于浮游生物中,，因此可能在海洋的營養(yǎng)循環(huán)等方面發(fā)揮著重要作用,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature，doi:10.1038/nature07218,，Bernard La Scola,，Didier Raoult
The virophage as a unique parasite of the giant mimivirus
Bernard La Scola1,6, Christelle Desnues1,6, Isabelle Pagnier1, Catherine Robert1, Lina Barrassi1, Ghislain Fournous1, Michèle Merchat2, Marie Suzan-Monti1, Patrick Forterre3,4, Eugene Koonin5 & Didier Raoult1
URMITE, Centre National de la Recherche Scientifique UMR IRD 6236, Faculté de Médecine, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 5, France
Climespace, 185 Rue de Bercy, 75012 Paris, France
Biologie Moléculaire du Gène chez les Extrêmophiles, Institut de Génétique et Microbiologie, Bâtiment 409, Université Paris Sud, Centre d'Orsay, 91405 Orsay Cedex, France
Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France
National Center for Biotechnology Information (NCBI), National Library of Medicine, National Institutes of Health, Building 38A, Room 5N503, 8600 Rockville Pike, Bethesda, Maryland 20894, USA
These authors contributed equally to this work.
Correspondence to: Didier Raoult1 Correspondence and requests for materials should be addressed to D.R. (Email: [email protected]).
Viruses are obligate parasites of Eukarya, Archaea and Bacteria. Acanthamoeba polyphaga mimivirus (APMV) is the largest known virus; it grows only in amoeba and is visible under the optical microscope. Mimivirus possesses a 1,185-kilobase double-stranded linear chromosome whose coding capacity is greater than that of numerous bacteria and archaea1, 2, 3. Here we describe an icosahedral small virus, Sputnik, 50 nm in size, found associated with a new strain of APMV. Sputnik cannot multiply in Acanthamoeba castellanii but grows rapidly, after an eclipse phase, in the giant virus factory found in amoebae co-infected with APMV4. Sputnik growth is deleterious to APMV and results in the production of abortive forms and abnormal capsid assembly of the host virus. The Sputnik genome is an 18.343-kilobase circular double-stranded DNA and contains genes that are linked to viruses infecting each of the three domains of life Eukarya, Archaea and Bacteria. Of the 21 predicted protein-coding genes, eight encode proteins with detectable homologues, including three proteins apparently derived from APMV, a homologue of an archaeal virus integrase, a predicted primase–helicase, a packaging ATPase with homologues in bacteriophages and eukaryotic viruses, a distant homologue of bacterial insertion sequence transposase DNA-binding subunit, and a Zn-ribbon protein. The closest homologues of the last four of these proteins were detected in the Global Ocean Survey environmental data set5, suggesting that Sputnik represents a currently unknown family of viruses. Considering its functional analogy with bacteriophages, we classify this virus as a virophage. The virophage could be a vehicle mediating lateral gene transfer between giant viruses.
