Evolution of the syntrophic interaction between Desulfovibrio vulgaris and Methanosarcina barkeri: Involvement of an ancient horizontal gene transfer

The sulfate reducing bacteria Desulfovibrio vulgaris and the methanogenic archaea Methanosarcina barkeri can grow syntrophically on lactate. In this study, a set of three closely located genes, DVU2103, DVU2104, and DVU2108 of D. vulgaris, was found to be up-regulated 2- to 4-fold following the lifestyle shift from syntroph to sulfate reducer; moreover, none of the genes in this gene set were differentially regulated when comparing gene expression from various D. vulgaris pure culture experiments. Although exact function of this gene set is unknown, the results suggest that it may play roles related to the lifestyle change of D. vulgaris from syntroph to sulfate reducer. This hypothesis is further supported by phylogenomic analyses showing that homologies of this gene set were only narrowly present in several groups of bacteria, most of which are restricted to a syntrophic lifestyle, such as Pelobacter carbinolicus, Syntrophobacter fumaroxidans, Syntrophomonas wolfei, and Syntrophus aciditrophicus. Phylogenetic analysis showed that all three individual genes in the gene set tended to be clustered with their homologies from archaeal genera, and they were rooted on archaeal species in the phylogenetic trees, suggesting that they were horizontally transferred from archaeal methanogens. In addition, no significant bias in codon and amino acid usages was detected between these genes and the rest of the D. vulgaris genome, suggesting the gene transfer may have occurred early in the evolutionary history so that sufficient time has elapsed to allow an adaptation to the codon and amino acid usages of D. vulgaris. This report provides novel insights into the origin and evolution of bacterial genes linked to the lifestyle change of D. vulgaris from a syntrophic to a sulfate-reducing lifestyle.     

An anti-endotoxin peptide that generates from the amino-terminal domain of complement regulatory protein C1 inhibitor

C1 inhibitor (C1INH), a complement regulatory protein, prevents endotoxin shock via a direct interaction of the amino-terminal domain with gram-negative bacterial lipopolysaccharide (LPS). Importantly, the cleaved, inactive C1INH still is an anti-endotoxin effector indicating the anti-endotoxin peptide that generates from the amino-terminal domain of C1INH. In this study, we first identified that a cleaved fragment within the major part of the amino-terminal domain in in vitro proteolytic analysis of C1INH had an ability to bind to LPS. We synthesized several peptides overlapping the C1INH cleaved fragment. Among these synthetic peptides, a 13-mer derivative peptide at position from 18 to 30, named N2((18-30)), exhibited the most powerful anti-endotoxin activity in vitro, enlightening that it was most strong at binding to LPS, inhibiting the interaction of LPS with LPS-binding protein (LBP), blocking LPS binding to CD14(+) cells, and suppressing production of tumor necrosis factor (TNF)-alpha by murine macrophages, RAW 264.7. In the murine endotoxin shock model, the peptide N2((18-30)) protected mice from LPS-induced lethal septic shock by inhibiting macrophage activation. These data indicate that the peptide N2((18-30)) derived from the amino-terminal region of C1INH is anti-endotoxin.     

6种重金属对赤子爱胜蚓的急性毒性效应与风险评价

【背景】近年来,土壤重金属污染问题日益凸显,对生态环境、食品安全和人体健康构成了严重威胁,其急性毒性尚未明确。【方法】采用滤纸接触法和人工土壤法测定了铜(Cu2+)、锌(Zn2+)、镍(Ni+)、镉(Cd2+)、铅(Pb2+)和锰(Mn2+)等6种重金属对赤子爱胜蚓的急性毒性效应,并参照欧盟指令91/414/EEC标准评价了其环境风险。【结果】滤纸接触法48h测定结果表明,6种重金属对蚯蚓的LC50为3.17(2.53～3.81)～90.42(69.45～140.47)μg.cm-2,其毒性次序为Cu2+>Zn2+>Ni+>Cd2+>Pb2+>Mn2+。人工土壤法14d测定结果表明,6种重金属对蚯蚓的LC50为1347(1236～1453)～6936(6144～8930)mg.kg-1,其毒性次序为Cu2+>Cd2+>Ni+>Zn2+>Mn2+>Pb2+。风险评价结果显示,Cu2+、Zn2+、Ni+、Cd2+、Pb2+和Mn2+等6种重金属的暴露比(toxicity/exposureratio,TER)分别为3.37、4.46、8.68、1428、13.87和5.85。【结论与意义】6种重金属对土壤动物蚯蚓均具有潜在的毒性效应。Cu2+、Zn2+、Ni+、Mn2+等4种重金属对赤子爱胜蚓存在急性毒性风险,而Cd2+和Pb2+对赤子爱胜蚓的急性毒性风险水平是可接受的。该评价结果可为我国制定基于风险的土壤环境质量标准提供依据。     

1982-2012年中亚地区植被时空变化特征及其与气候变化的相关分析

干旱区植被生态系统对气候变化极为敏感,并且干旱区的植被变化研究对全球碳循环具有重要意义。然而近几十年来,中亚干旱区植被对气候变化的响应机制尚不甚明朗。利用归一化植被指数NDVI数据集和MERRA（Modern-Era Retrospective Analysis for Research and Applications）气象数据,采用经验正交函数（EOF,Empirical Orthogonal Function）和最小二乘法等方法系统分析了31a（1982-2012年）来中亚地区NDVI在不同时间尺度的时空变化特征。进一步分析和研究NDVI与气温和降水的相关性,结果表明：1982-2012年,中亚地区年NDVI总体呈现缓慢增长趋势,而1994年以后年NDVI呈现明显下降趋势,尤其在哈萨克斯坦北部草原地区下降趋势尤为突出。这可能是由于过去30年间,中亚地区降水累计量的持续减少造成的。NDVI的季节变化表明春季NDVI增长最为明显,冬季则显著下降。与平原区相比,中亚山区的NDVI值增长幅度最大,并且山区年NDVI与季节NDVI呈现显著增加趋势（P < 0.05）。中亚地区年NDVI与年降水量正相关,而年NDVI与气温变化存在弱负相关。年NDVI和气温的正相关中心在中亚南部地区,负相关中心则出现在哈萨克斯坦的西部和北部地区;NDVI和降水的相关性中心刚好与气温相反。此外,在近30年间的每年6月至9月,中亚地区NDVI与气温存在近一个月的时间延迟现象。本研究为中亚干旱区生态系统变化和中亚地区碳循环的估算提供科学依据。     

生态系统服务需求、供给和消费研究进展

生态系统服务的持续供给是社会和自然可持续发展的基础,人类通过对生态系统服务的消费来满足需求和提高自身福祉。研究人类对生态系统服务的需求、消费,分析生态系统服务的供给与需求关系,对生态系统的管理、土地发展规划和资源的合理有效配置具有重要意义。首先分析了生态系统服务需求、供给和消费的内涵与特征,辨析了生态系统服务的有效需求和潜在需求、有效供给与潜在供给,进而提出了生态系统服务需求与供给研究框架,指出应研究生态系统服务供给和需求的空间关联以及生态系统服务需求弹性差异,进而因地制宜地调控生态系统服务供给使得生态系统服务效用最大化。梳理并比较了对生态系统服务供给和需求的量化指标和研究方法,包括基于土地利用和土地覆被的生态系统服务供需关系矩阵法、生态足迹法、公众参与法、模型计算法等。提出了未来的相关研究主要应从不同群体的需求弹性差异、跨学科与多源数据结合的需求定量评估方法、供需关系的多尺度分析、生态系统服务需求与人类福祉的耦合机制拓展等方面展开,为生态系统服务调控管理和社会的可持续发展提供切实可行的科学依据。     

锡林郭勒盟煤电基地开发生态脆弱性评价

内蒙古锡林郭勒盟国家大型煤电基地的建设,对我国华北和华东区域能源安全具有重要的作用。但随着锡盟大型煤电基地的开发,其对锡林郭勒盟这一具有重要生态屏障功能的典型草原区的生态环境造成不利影响。通过对区域生态敏感性、生态弹性及生态压力的系统研究,建立了基于生态敏感性、生态弹性及生态压力的生态脆弱性评价模型,对该区域生态脆弱性进行了评价。结果表明,锡盟地区总体生态环境质量较好,但呈现由东北向西南递减的特征。研究为锡林郭勒盟国家大型煤电基地的开发建设,区域协调发展与生态环境保护提供理论支持。     

基于解释结构模型的煤电一体化开发生态环境累积效应识别

为了对煤电一体化开发的生态环境累积效应进行识别与分析,从煤电一体化开发的主要开采建设活动、土壤环境、水资源、大气环境、生物、景观、生态7方面共筛选出29个生态环境因子,综合文献调查、专家调查问卷与访谈等方法,分析了各生态环境因子之间的相互作用关系.运用解释结构模型(ISM)分析了各因子间的关联关系与层次结构,揭示了不同开发建设活动产生累积效应的途径.结合具体的评价与管理需求,提出了煤电一体化开发生态环境累积效应研究与评估整体框架.研究结果可以为煤电一体化开发的规划与管理提供一定的理论基础与技术手段.     

Polymorphism of rs3737597 in DISC1 Gene on Chromosome 1q42.2 in sALS Patients: a Chinese Han Population Case-Control Study

Although lots of genes have been revealed to relate to sporadic amyotrophic lateral sclerosis (sALS), its genetic mechanisms still need to be further explored. We aimed to search the novel genetic factors of sALS and assess their contribution. We constructed an integrative dataset based on the 3227 subsignificant genes (P value?<?0.01) from two sALS-related genome-wide association studies (GWAS) (the US and Irish studies). A significant replication between both studies was confirmed by the gene set enrichment analysis in the integral level (P value?<?10^?4). Using the pathway overrepresentation analysis, we revealed the 34 shared Gene Ontology (GO) biological processes from the two independent studies (P value?<?0.01). Among these pathways, the nervous system developmental pathway (NSD function, GO:0007399) was further supported by the previously reported genes related to sALS (P value?=?3.28e?12). Importantly, four of 17 NSD-function-related target genes (disrupted-in-schizophrenia-1 (DISC1), CNTN4, NRXN3, and ERBB4) presented a considerable association with sALS in both studies. To further verify the association between the NSD function target genes and sALS, we preformed a two-stage case–control study based on 500 sALS patients and 500 controls of Chinese Han populations from mainland. A polymorphism of rs3737597 in DISC1 gene involved in the nervous system developmental pathway was closely associated with sALS. The nervous system developmental pathway is a potential pathogenesis of sALS, among them, the polymorphism of rs3737597 in DISC1 might play some roles.