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Dating the skull from Broken Hill, Zambia, and its position in human evolution 期刊论文
NATURE, 2020, 580 (7803) : 372-+
作者:  Mergner, Julia;  Frejno, Martin;  List, Markus;  Papacek, Michael;  Chen, Xia;  Chaudhary, Ajeet;  Samaras, Patroklos;  Richter, Sandra;  Shikata, Hiromasa;  Messerer, Maxim;  Lang, Daniel;  Altmann, Stefan;  Cyprys, Philipp;  Zolg, Daniel P.;  Mathieson, Toby;  Bantscheff, Marcus
收藏  |  浏览/下载:18/0  |  提交时间:2020/07/03

The cranium from Broken Hill (Kabwe) was recovered from cave deposits in 1921, during metal ore mining in what is now Zambia(1). It is one of the best-preserved skulls of a fossil hominin, and was initially designated as the type specimen of Homo rhodesiensis, but recently it has often been included in the taxon Homo heidelbergensis(2-4). However, the original site has since been completely quarried away, and-although the cranium is often estimated to be around 500 thousand years old(5-7)-its unsystematic recovery impedes its accurate dating and placement in human evolution. Here we carried out analyses directly on the skull and found a best age estimate of 299 +/- 25 thousand years (mean +/- 2s). The result suggests that later Middle Pleistocene Africa contained multiple contemporaneous hominin lineages (that is, Homo sapiens(8,9), H. heidelbergensis/H. rhodesiensis and Homo naledi(10,11)), similar to Eurasia, where Homo neanderthalensis, the Denisovans, Homo floresiensis, Homo luzonensis and perhaps also Homo heidelbergensis and Homo erectus(12) were found contemporaneously. The age estimate also raises further questions about the mode of evolution of H. sapiens in Africa and whether H. heidelbergensis/H. rhodesiensis was a direct ancestor of our species(13,14).


  
An anti-CRISPR viral ring nuclease subverts type III CRISPR immunity 期刊论文
NATURE, 2020, 577 (7791) : 572-+
作者:  Athukoralage, Januka S.;  McMahon, Stephen A.;  Zhang, Changyi;  Grueschow, Sabine;  Graham, Shirley;  Krupovic, Mart;  Whitaker, Rachel J.;  Gloster, Tracey M.;  White, Malcolm F.
收藏  |  浏览/下载:21/0  |  提交时间:2020/07/03

The CRISPR system in bacteria and archaea provides adaptive immunity against mobile genetic elements. Type III CRISPR systems detect viral RNA, resulting in the activation of two regions of the Cas10 protein: an HD nuclease domain (which degrades viral DNA)(1,2) and a cyclase domain (which synthesizes cyclic oligoadenylates from ATP)(3-5). Cyclic oligoadenylates in turn activate defence enzymes with a CRISPR-associated Rossmann fold domain(6), sculpting a powerful antiviral response(7-10) that can drive viruses to extinction(7,8). Cyclic nucleotides are increasingly implicated in host-pathogen interactions(11-13). Here we identify a new family of viral anti-CRISPR (Acr) enzymes that rapidly degrade cyclic tetra-adenylate (cA(4)). The viral ring nuclease AcrIII-1 is widely distributed in archaeal and bacterial viruses and in proviruses. The enzyme uses a previously unknown fold to bind cA(4) specifically, and a conserved active site to rapidly cleave this signalling molecule, allowing viruses to neutralize the type III CRISPR defence system. The AcrIII-1 family has a broad host range, as it targets cA(4) signalling molecules rather than specific CRISPR effector proteins. Our findings highlight the crucial role of cyclic nucleotide signalling in the conflict between viruses and their hosts.


Bacteria and archaea use cyclic oligoadenylate molecules as part of the CRISPR system for antiviral defence  here, a family of viral enzymes that rapidly degrades cyclic oligoadenylates is identified and biochemically and structurally described.


  
Modelling site site index of Chinese fir plantations using a random effects model across regional site types in Hunan province, China 期刊论文
FOREST ECOLOGY AND MANAGEMENT, 2019, 446: 143-150
作者:  Zhu, Guangyu;  Hu, Song;  Chhin, Sophan;  Zhang, Xiongqing;  He, Peng
收藏  |  浏览/下载:17/0  |  提交时间:2019/11/27
Chinese fir  Site effect  Site type  Polymorphic site index model  Nonlinear mixed model