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《Science》7月30日内容提要（中英文对照）
痤疮俗称粉刺，全世界约有80%的人都长粉刺。如今科学家测序了与这种皮肤病有关的细菌的基因组。Holger Brueggemann和同事说，这个基因组的测序能帮助找到治疗痤疮以及与该细菌有关的其他皮肤病的药物。痤疮丙酸杆菌（Propionibacterium Acnes）是成年人皮肤上个一个主要居民。它一般无害地存在于毛孔的皮脂腺中，但可能通过几种机制造成痤疮的形成。研究人员发现痤疮丙酸杆菌的基因组编码了2,333个基因，他们还找到了与该细菌进攻和破坏人类皮肤的能力有关的基因。其中可能有与痤疮或其它与该细菌有关的引起发炎的物质。 报告：The Complete Genome Sequence of Propionibacterium Acnes, a Commensal of Human Skin, Holger Brüggemann, et al.
The Complete Genome Sequence of
Science, Vol 305, Issue 5684, 671-673 , 30 July 2004
Propionibacterium Acnes, a Commensal of Human Skin
Propionibacterium acnes is a major inhabitant of adult human skin, where it resides within sebaceous follicles, usually as a harmless commensal although it has been implicated in acne vulgaris formation. The entire genome sequence of this Gram-positive bacterium encodes 2333 putative genes and revealed numerous gene products involved in degrading host molecules, including sialidases, neuraminidases, endoglycoceramidases, lipases, and pore-forming factors. Surface-associated and other immunogenic factors have been identified, which might be involved in triggering acne inflammation and other P. acnes–associated diseases.
一块月球岩石的历史
对一块新的月球陨石 的研究揭示，这块岩石在被第四次撞击从月球上抛出之前，曾经历过三次撞击事件。这些欧洲和美国的作者分别确定了四次撞击事件的年代，这将帮助研究人员进一步优化他们的月球演化模型。陨石Sayh al Uhaymir 169大约是成年人拳头大小：70 x 43 x 40 立方公分，是2002年在阿曼发现的。Edwin Gnos和同事对这块石头进行了地质学和化学成分的分析。它独特的化学组分使科学家能准确的确定它来自月球的什么地方：Lalande撞击坑。作者的数据为这块岩石提供了它在月球时的主要里程碑。每次撞击都使它改变过位置，在大约34万年前，它被第四次撞击抛入太空。最后，在环绕地球或太阳运转了一段时间后，这块陨石被地球的重力场所捕获。一篇相关的研究评述进一步讨论了这些发现。
报告：Pinpointing the Source of a Lunar Meteorite: Implications for the Evolution of the Moon, Edwin Gnos, et al.
Science, Vol 305, Issue 5684, 657-659 , 30 July 2004
Pinpointing the Source of a Lunar Meteorite: Implications for the Evolution of the Moon
Edwin Gnos,1* Beda A. Hofmann,2 Ali Al-Kathiri,1 Silvio Lorenzetti,3 Otto Eugster,3 Martin J. Whitehouse,4 Igor M. Villa,1 A. J. Timothy Jull,5 Jost Eikenberg,6 Bernhard Spettel,7 Urs Krähenbühl,8 Ian A. Franchi,9 Richard C. Greenwood9
The lunar meteorite Sayh al Uhaymir 169 consists of an impact melt breccia extremely enriched with potassium, rare earth elements, and phosphorus [thorium, 32.7 parts per million (ppm); uranium, 8.6 ppm; potassium oxide, 0.54 weight percent], and adherent regolith. The isotope systematics of the meteorite record four lunar impact events at 3909 ± 13 million years ago (Ma), 2800 Ma, 200 Ma, and <0.34 Ma, and collision with Earth sometime after 9.7 ± 1.3 thousand years ago. With these data, we can link the impact-melt breccia to Imbrium and pinpoint the source region of the meteorite to the Lalande impact crater.
吃鲸骨的虫子
科学家发现了第一个吃死鲸骨头的虫子。生存在这个虫子的绿根中的共生细菌帮助将脂肪和其他骨头成份变为虫子的食物。科学家在美国加利福尼亚州蒙特利海湾底部发现了长在一只幼年灰鲸骨架中的雌性管虫，其中有些和人的食指那么长。这些雌虫有一个外管和一个肌肉的躯干，一个携带卵子的卵管，以及留给雄性的足够的空间。微观尺寸的雄性没有嘴，也没有肠道，靠它们微小身体中的脂肪球生存。雌虫的充满细菌的根和产生卵的组织长到骨骼上，它们还有红色或红白条的羽毛状结构的触须 。触须中的血色素 使其具有红颜色，也为虫子和寄生于虫子的细菌捕捉氧。这些新虫子的物种与深海热喷中的虫子有关，组成一个新的属，作者将其命名为Osedax，是“吞食骨头”的意思。
报告：Osedax: Bone-Eating Marine Worms with Dwarf Males, G. W. Rouse, S. K. Goffredi, and R. C. Vrijenhoek
Science, Vol 305, Issue 5684, 668-671 , 30 July 2004
Osedax: Bone-Eating Marine Worms with Dwarf Males
We describe a new genus, Osedax, and two new species of annelids with females that consume the bones of dead whales via ramifying roots. Molecular and morphological evidence revealed that Osedax belongs to the Siboglinidae, which includes pogonophoran and vestimentiferan worms from deep-sea vents, seeps, and anoxic basins. Osedax has skewed sex ratios with numerous dwarf (paedomorphic) males that live in the tubes of females. DNA sequences reveal that the two Osedax species diverged about 42 million years ago and currently maintain large populations ranging from 105 to 106 adult females.
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作者:admin@医学,生命科学 2011-03-31 05:11
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