The finished DNA sequence of human chromosome 12

Human chromosome 12 contains more than 1,400 coding genes and 487 loci that have been directly implicated in human disease. The q arm of chromosome 12 contains one of the largest blocks of linkage disequilibrium found in the human genome. Here we present the finished sequence of human chromosome 12, which has been finished to high quality and spans approximately 132 megabases, representing approximately 4.5% of the human genome. Alignment of the human chromosome 12 sequence across vertebrates reveals the origin of individual segments in chicken, and a unique history of rearrangement through rodent and primate lineages. The rate of base substitutions in recent evolutionary history shows an overall slowing in hominids compared with primates and rodents.     

Compartmentalization of S-RNase and HT-B degradation in self-incompatible Nicotiana

Pollen-pistil interactions are crucial for controlling plant mating. For example, S-RNase-based self-incompatibility prevents inbreeding in diverse angiosperm species. S-RNases are thought to function as specific cytotoxins that inhibit pollen that has an S-haplotype that matches one of those in the pistil. Thus, pollen and pistil factors interact to prevent mating between closely related individuals. Other pistil factors, such as HT-B, 4936-factor and the 120 kDa glycoprotein, are also required for pollen rejection but do not contribute to S-haplotype-specificity per se. Here we show that S-RNase is taken up and sorted to a vacuolar compartment in the pollen tubes. Antibodies to the 120 kDa glycoprotein label the compartment membrane. When the pistil does not express HT-B or 4936-factor, S-RNase remains sequestered, unable to cause rejection. Similarly, in wild-type pistils, compatible pollen tubes degrade HT-B and sequester S-RNase. We suggest that S-RNase trafficking and the stability of HT-B are central to S-specific pollen rejection.     

The Constituents of Diterpenoids from Isodon excisa

从唇形科尾叶香茶菜叶子的甲醇提取物中，分离提取了４个对映－贝壳杉烯型二萜，并利用核磁共振氢谱和碳谱，以及质谱、红外光谱和紫外光谱等方法，对以上各化合物进行了结构鉴定．化合物１在该植物的文献中未见报道．     

Low European methyl chloroform emissions inferred from long-term atmospheric measurements

Methyl chloroform (CH3CCl3, 1,1,1,-trichloroethane) was used widely as a solvent before it was recognized to be an ozone-depleting substance and its phase-out was introduced under the Montreal Protocol. Subsequently, its atmospheric concentration has declined steadily and recent European methyl chloroform consumption and emissions were estimated to be less than 0.1 gigagrams per year. However, data from a short-term tropospheric measurement campaign (EXPORT) indicated that European methyl chloroform emissions could have been over 20 gigagrams in 2000 (ref. 6), almost doubling previously estimated global emissions. Such enhanced emissions would significantly affect results from the CH3CC13 method of deriving global abundances of hydroxyl radicals (OH) (refs 7-12)-the dominant reactive atmospheric chemical for removing trace gases related to air pollution, ozone depletion and the greenhouse effect. Here we use long-term, high-frequency data from Mace Head, Ireland and Jungfraujoch, Switzerland, to infer European methyl chloroform emissions. We find that European emission estimates declined from about 60 gigagrams per year in the mid-1990s to 0.3-1.4 and 1.9-3.4 gigagrams per year in 2000-03, based on Mace Head and Jungfraujoch data, respectively. Our European methyl chloroform emission estimates are therefore higher than calculated from consumption data, but are considerably lower than those derived from the EXPORT campaign in 2000 (ref. 6).     

中国甘肃一例前足迹主导的翼龙足迹组合:对行为学的影响（英文）

翼龙是已知的、最早飞上天际的脊椎动物,目前已经发现了成千上万件化石,代表着这一大家族从晚三叠世到晚白垩世在全球范围内的蓬勃发展史.自2004年甘肃盐锅峡地区首次报道翼龙足迹以来,中国陆续发现了一批翼龙足迹化石,绝大多数的足迹点都保存了翼龙的前后足迹.2013年,我们在盐锅峡地区发现了至少20个翼龙前足迹的凸型足迹,而没有发现任何后足迹,这些足迹可归于一个单独翼龙遗迹属——Pteraichnus.这是中国第一次发现由前足迹主导的翼龙足迹组合,这可能反映了翼龙前后足迹在同等保存条件下的不同深度.更重要的是,盐锅峡的这批翼龙足迹与当地发现的大量虫迹相关,一些足迹甚至就保存在虫迹面上,这些虫迹包括Cochlichnus,Spongeliomorpha和Paleophycus,因此推断这批翼龙造迹者很可能以这些无脊椎动物造迹者为食.