Pseudomonas duriflava sp nov., isolated from a desert soil

A Gram-negative, rod-shaped, non-motile, non-spore-forming bacterium, designated strain HR2(T) was isolated from a soil sample from the Talklimaken Desert in Xinjiang Province, China. Strain HR2(T) grew optimally at pH 7.0-8.0 and 30-37 degrees C in the presence of 0-1% (w/v) NaCl. An analysis of 16S rRNA gene sequences revealed that strain HR2(T) fell within the radiation of the genus Pseudomonas, the highest level of similarity being found with respect to Pseudomonas luteola IAM 13000(T) (97.5%); the levels of sequence similarity with respect to other recognized Pseudomonas species were < 96.4%. DNA-DNA hybridization showed that the genetic relatedness between strain HR2(T) and P. luteola IAM 13000(T) was 53.2%. The G + C content of the genomic DNA of strain HR2(T) was 55.2 mol%. The major fatty acids were 18: 1, summed feature 3 and 16:0. The hydroxylated fatty acids 10:0 3-OH, 12:0 3-OH and 12:0 2-OH were also present. The data obtained in this polyphasic study indicated that this isolate represents a novel species of the genus Pseudomonas, for which the name Pseudomonas duriflava sp. nov. is proposed, The type strain is HR2(T) (=KCTC 221129(T) =CGMCC 1.6858(T)).

Degradation of tropical forest in Hainan, China, 1991-2008: Conservation implications for Hainan Gibbon (Nomascus hainanus)

The Hainan gibbon (Nomascus hainanus) is one of the most endangered primates in the world, confined to mature natural forest in Hainan Island, China. We assessed changes in habitat condition on the island between 1991 and 2008, using vegetation maps generated by remote-sensing images. We defined forest suitable for gibbons based on composition, tree size and canopy cover. During the 17-year period, the area of suitable gibbon forest decreased by 540 km(2) (35%) across the whole island, and by 6.3 km(2) (7%) in the locality of the sole remaining gibbon population at Bawangling National Nature Reserve. The forest patches large enough (>1 km(2)) to support a gibbon group decreased from 754 km(2) to 316 km(2) in total area, and from 92 to 64 in number. Suitable natural forest was mainly replaced by plantations below 760 m, or degraded by logging, grazing and planting of pines above 760 m. Meanwhile, forests in former confirmed gibbon areas became more fragmented: mean area of patches decreased by 53%. We mapped the patches of natural forest in good condition which could potentially support gibbons. We recommend a freeze on further expansion of plantations between core patches at Bawangling, Jiaxi-Houmiling and Yinggeling Nature Reserves in accordance with forest protection regulations; establishment of nature reserves in currently unprotected natural forest patches elsewhere in line with the local government's nature reserve expansion policy; and active natural-forest restoration between remaining fragments at Bawangling. (C) 2010 Elsevier Ltd. All rights reserved.

森林认证与系统思想

森林认证是缓解全球森林退化、实现可持续发展战略的重要手段之一。它包括森林经营认证和森林产品认证。森林认证将影响到世界森林资源、各国林业发展以及生态、经济和社会。森林认证是一项复杂的系统工程,涉及国家政策和国民经济的方方面面。只有利用系统理论,才能更好分析论证在中国特定条件下的森林认证系统;在系统思想指导下,找出我国森林认证的关键要素、主要子系统和最优结构,才能发挥森林认证体系的最佳功能。

高原鳅属Triplophysa鱼类的分子系统发育和生物地理学研究

高原鳅属Triplophysa鱼类广泛分布于亚洲中部的高原地区,是青藏高原鱼类区系重要的组成部分．它们对高原环境表现出极强的适应性,是已知世界上分布海拔最高的鱼类,采用线粒体DNA细胞色素凸基因序列分析了青藏高原及其邻近地区13个水系30个地点22种高原鳅属鱼类的分子系统发育关系．结果表明高原鳅属鱼类不是一个单系群,赫氏鳅亚属Hedinich- thys的种类嵌入到其他条鳅亚科鱼类分支中,而依据第二性征划分的高原鳅亚属Triplophysa是一个单系群．在高原鳅亚属中,最先发生分歧的是分布于黄河上游的似鲶

斜带石斑鱼囊胚期胚胎和尾芽期胚胎差异表达基因的筛选及克隆

以斜带石斑鱼囊胚期胚胎和尾芽期胚胎分别作为检验组和驱动组,构建了石斑鱼囊胚期胚胎和尾芽期胚胎的抑制性差减杂交cDNA文库。以α-tubulin作为检测指标,显示差减效率分别高达28和27。分别取囊胚期胚胎和尾芽期胚胎各192和960个PCR阳性克隆进行斑点杂交,得到15个囊胚期和131个尾芽期的斑点杂交阳性克隆。测序和数据库比对分析表明,囊胚期15个阳性克隆中有11个已知基因的cDNA片段和没有同源性的4个cDNA片段;而在尾芽期的131个阳性克隆中,有123个已知基因的cDNA片段和8个没有同源性的cD

武汉东湖上覆水和沉积物中磷形态的垂直分布特征

武汉东湖是有代表性的城市浅水型湖泊。于春、夏两季对东湖庙湖湖区的上覆水和沉积物柱状样品进行了磷的形态分析,研究了各种磷形态在上覆水及沉积物垂直方向上的分布特征。结果表明,春夏两季东湖上覆水总磷(TP)含量分别为1.11和1.25mg·L-1,超过国家标准近6倍,富营养化程度严重。春季湖水中磷主要以颗粒态形式存在,夏季主要以溶解态形式存在。春季湖区沉积物中铁结合磷(Fe-P)比例最大,占沉积物TP的44.3%,夏季闭蓄磷(OcP)比例最大,占TP的36.3%,高比例的Fe-P从沉积物角度说明了庙湖湖区的污染

硒对小麦和水稻种子萌发的生态毒理效应的比较研究

通过水培试验,比较研究了硒在不同浓度下对小麦和水稻种子萌发及幼苗生长的生态毒理效应。结果表明,硒在适量范围内(<0.5 mg.L-1)对种子萌发过程中各生理指标有促进作用,高剂量(>5 mg.L-1)时,对种子活力、α-淀粉酶及幼苗和根生长具有胁迫效应。硒对小麦种子发芽各指标抑制率大于水稻,硒对种子根伸长的抑制率远远大于发芽抑制率。对硒浓度与种子发芽各项指标抑制率相关分析,呈显著正相关。应用小麦根伸长抑制率可作为化学物质生态风险评价的一项生物标志物。

Regression on fixed-rank positive semidefinite matrices: A Riemannian approach

The paper addresses the problem of learning a regression model parameterized by a fixed-rank positive semidefinite matrix. The focus is on the nonlinear nature of the search space and on scalability to high-dimensional problems. The mathematical developments rely on the theory of gradient descent algorithms adapted to the Riemannian geometry that underlies the set of fixedrank positive semidefinite matrices. In contrast with previous contributions in the literature, no restrictions are imposed on the range space of the learned matrix. The resulting algorithms maintain a linear complexity in the problem size and enjoy important invariance properties. We apply the proposed algorithms to the problem of learning a distance function parameterized by a positive semidefinite matrix. Good performance is observed on classical benchmarks. © 2011 Gilles Meyer, Silvere Bonnabel and Rodolphe Sepulchre.