Haloquadratum walsbyi: limited diversity in a global pond.
Haloquadratum walsbyi: limited diversity in a global pond.
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DOI：
10.1371/journal.pone.0020968
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Oesterhelt D
中科院分区：
文献类型：
--
作者：
Dyall-Smith ML;Pfeiffer F;Klee K;Palm P;Gross K;Schuster SC;Rampp M;Oesterhelt D
华氏盐方藻通常在高盐水域的微生物区系中占主导地位。它的细胞是非常脆弱的正方形，需要>14%（w/v）的盐来生长，这种特性应该会限制它的扩散，并促进地理隔离和分化。为了评估这一点，比较了从地球上接近最远距离的地点恢复的两个分离株的基因组序列。两条染色体的大小为3.1 MB，每条序列有84%高度相似（98.6%相同），构成核心序列。该共享序列的orf是完全合成的（在基因组方向和顺序上保守），没有反转或重排。特定菌株的插入/删除可以精确地绘制，通常允许推断遗传事件。许多推断缺失与短的直接重复（4 - 20bp）有关。缺失耦合插入是频繁的，在相同的位置产生不同的序列。在插入和删除的序列是同源的情况下，这导致在共同的合成背景下的变异基因（如其他人已经描述的）。Cas/CRISPR系统存在于C23T中，但在HBSQ001中丢失，除了少数间隔残余。在这两种菌株中都出现了许多类型的可移动遗传元件，其中大多数似乎是活跃的，有些是专门针对其他菌株的。菌株C23T携带两个~ 6kb的质粒，与卤代古菌中常见的卤代病毒His1和卤代病毒/质粒基因簇附近的序列相似。删除耦合插入显示Hqr。walsbyi是通过吸收和精确整合外来DNA而进化的，这些外来DNA可能来自近亲。变化也由可移动的遗传因素驱动，但这些因素本身并不能解释在这个物种中发现的非典型的低基因编码密度。尽管存在活跃的基因组重排系统，但显著的基因组保护表明该物种具有有效的全球传播系统和高度的选择适应性。
Haloquadratum walsbyi commonly dominates the microbial flora of hypersaline waters. Its cells are extremely fragile squares requiring >14%(w/v) salt for growth, properties that should limit its dispersal and promote geographical isolation and divergence. To assess this, the genome sequences of two isolates recovered from sites at near maximum distance on Earth, were compared. Both chromosomes are 3.1 MB in size, and 84% of each sequence was highly similar to the other (98.6% identity), comprising the core sequence. ORFs of this shared sequence were completely synteneic (conserved in genomic orientation and order), without inversion or rearrangement. Strain-specific insertions/deletions could be precisely mapped, often allowing the genetic events to be inferred. Many inferred deletions were associated with short direct repeats (4–20 bp). Deletion-coupled insertions are frequent, producing different sequences at identical positions. In cases where the inserted and deleted sequences are homologous, this leads to variant genes in a common synteneic background (as already described by others). Cas/CRISPR systems are present in C23T but have been lost in HBSQ001 except for a few spacer remnants. Numerous types of mobile genetic elements occur in both strains, most of which appear to be active, and with some specifically targetting others. Strain C23T carries two ∼6 kb plasmids that show similarity to halovirus His1 and to sequences nearby halovirus/plasmid gene clusters commonly found in haloarchaea. Deletion-coupled insertions show that Hqr. walsbyi evolves by uptake and precise integration of foreign DNA, probably originating from close relatives. Change is also driven by mobile genetic elements but these do not by themselves explain the atypically low gene coding density found in this species. The remarkable genome conservation despite the presence of active systems for genome rearrangement implies both an efficient global dispersal system, and a high selective fitness for this species.
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DOI：
10.1155/2010/608243
发表时间：
2010-07-07
期刊：
Archaea (Vancouver, B.C.)
影响因子：
--
作者：
Ellen AF;Zolghadr B;Driessen AM;Albers SV
通讯作者：
Albers SV
GC-Profile：一种基于Web的工具，用于可视化和分析基因组序列中GC含量的变化。
影响因子：
14.9
作者：
Gao, Feng;Zhang, Chun-Ting
通讯作者：
Zhang, Chun-Ting
影响因子：
1.4
作者：
GuixaBoixareu, N;CalderonPaz, JI;PedrosAlio, C
通讯作者：
PedrosAlio, C
影响因子：
3.2
作者：
Deveau, Helene;Barrangou, Rodolphe;Moineau, Sylvain
通讯作者：
Moineau, Sylvain
DOI：
10.1099/ijs.0.64690-0
发表时间：
2007-02-01
影响因子：
2.8
作者：
Burns, David G.;Janssen, Peter H.;Dyall-Smith, Mike L.
通讯作者：
Dyall-Smith, Mike L.