沉水植物分布格局对湖泊水环境N、P因子影响

利用实地调查数据模拟保安湖沉水植物分布及水环境生态因子场。应用GIS空间分析功能 ,分别空间选取四种优势沉水植物 (金鱼藻CeratophyllumdemersumL .,穗状狐尾藻MyriophyllumspicatumL .,微齿眼子菜PotamogetonmaackianusA .Benn .,及苦草VallisneriaspiralisL .)的分布水域及无沉水植物分布水域的局部生态因子场。根据得到的局部因子场特征 ,比较分析不同水生植物分布格局对水环境中N、P因子的影响。结果显示四种沉水植物的分布对水环境中N、P因子均有显著影响 ,但效果和强度有所差异。四种植物各自分布水域内的N、P因子的平均浓度分别为 ,总氮 (TN) :穗状狐尾藻 (0 .774mg·L- 1 ) >苦草 (0 .71 4mg·L- 1 ) >金鱼藻 (0 .70 1mg·L- 1 ) >微齿眼子菜(0 .695mg·L- 1 ) ;总磷 (TP)平均含量 :穗状狐尾藻 (0 .1 2 3mg·L- 1 ) >微齿眼子菜 (0 .1 1 8mg·L- 1 ) >金鱼藻 (0 .1 0 7mg·L- 1 ) >苦草 (0 .0 79mg·L- 1 )。结果同时表明金鱼藻、微齿眼子菜和苦草对水中TN含量无显著影响 ,而穗状狐尾藻则明显可以提高水中TN水平。四种沉水植物均能有效吸收水中的P ,从而降低水中的TP含量。综合比较发现 ,穗状狐尾藻分布可以加重水体的营养程度     

梅子垭水库生态因子场的地统计学分析

应用地统计学方法,对梅子垭水库的典型理化因子的生态因子场的水平的2维空间格局进行了分析。通过空间相关性的分析,确定了生态因子场的整个空间和不同方位上的空间格局的变化情况。       

基于宏基因组的保安湖浮游动物多样性研究

研究于2019年春、夏、秋、冬四季对保安湖进行了水样采集, 基于宏基因组测序, 在优化物种鉴定和丰度计算方法的基础上, 考察了保安湖浮游动物的多样性、群落结构及其影响因素。共鉴定到浮游动物OTU 374种, 其中原生动物282个; 枝角类45个; 桡足类26个; 轮虫21个。从季节来看, 夏、秋季保安湖的浮游动物多样性高; 从湖区来看, 肖四海和主湖区浮游动物多样性高。季节因素对保安湖浮游动物群落结构的影响高于湖区影响。保安湖营养状态为中营养型, 水体温度、叶绿素a是影响保安湖浮游动物群落结构的主要环境因子, 不同类群与环境因子相关性不同, 总体可分为5类。其中原生动物优势类群为混合营养的纤毛虫和丝足虫, 同硝氮、化学需氧量、温度有明显的相关性, 而枝角类和桡足类同环境因子的关系较为相似, 与溶氧、叶绿素a、正磷酸盐存在明显相关。研究利用宏基因组方法对保安湖浮游动物多样性开展了研究, 为从浮游动物这一角度来理解保安湖这一江湖阻隔型湖泊的生物多样性的变化提供了支撑。     

栖息地环境对种群营养生态位的影响——以黄颡鱼为例

生态位是生态学研究的基础,目前关于环境指标是否直接影响营养生态位的分析研究很少。以高营养级鱼类黄颡鱼为研究对象,利用稳定同位素分析和相关分析,在太湖贡湖湾研究了氨氮、亚硝酸盐氮、硝酸盐氮、总氮、溶解性总氮、溶解性正磷酸盐、总磷、溶解性总磷、叶绿素等多个栖息地水环境因子对鱼类种群营养生态位的影响。结果表明,栖息地水环境对黄颡鱼总营养生态位影响不大,但部分栖息地水环境因子对分项营养生态位(包括浮游、底栖与肉食性)有影响。研究得知,栖息地水环境因子中氨氮、硝酸盐氮、总氮、溶解性总氮及溶解性总磷与浮游食性营养生态位显著正相关,氨氮、硝酸盐氮、总氮、溶解性总氮及溶解性总磷与肉食性营养生态位显著负相关,而底栖食性则主要受溶解性总磷的影响,与其显著正相关。水环境因子的季节变化影响水体中饵料资源的分布,进而影响鱼类的食物组成。     

保安湖水体细菌群落结构时空变化特征及驱动因子

为了探究保安湖水体细菌群落结构时空变化特征及驱动因子,研究于2019年春、夏、秋、冬四季采集保安湖水样,使用宏基因组测序技术对保安湖水体细菌群落的组成及多样性变化进行了研究。结果表明:(1)保安湖不同湖区细菌群落组成无显著差异(P>0.05);夏、秋季细菌丰富度、均匀度、香农及辛普森多样性指数均显著高于春、冬季(P<0.05),夏、秋季优势类群为变形菌门(Proteobacteria)、放线菌门(Actinobactetiota)、蓝藻门(Cyanobacteria),而春、冬季变形菌门(Proteobacteria)和放线菌门(Actinobactetiota)占主导地位;(2)温度、透明度、pH、溶解氧、高锰酸盐指数、叶绿素a及总磷等因素是保安湖水体细菌群落结构变化的重要驱动因子;(3)保安湖细菌群落构建过程在春、夏、秋季由随机性过程主导,在冬季由确定性过程主导;(4)保安湖细菌网络互作具有明显的季节特征,从春季到冬季,保安湖细菌种间相互作用逐渐紧密复杂。综上所述,保安湖水体细菌群落结构具有明显的季节变化特征,温度、透明度、pH、溶解氧、高锰酸盐指数等因素具有驱动水体细...     

保安湖沉水植物分布的GIS模拟

以GPS为辅助,在保安湖主体湖和桥墩湖进行沉水植物调查。将野外调查数据构建GIS数据库,基于GIS软件平台,运用Kringing插值法对保安湖沉水植物分布进行模拟。模拟结果清楚地显示出调查时保安湖沉水植物及4优势种(金鱼藻Ceratophyllum demersum L.、穗状狐尾藻Myriophyllum spicatum L.、微齿眼子菜Potamogeton maackianus A．Benn．及苦草Vallisneria spiralis L．)分别在湖中的分布情况。统计后结果表明沉水植物覆盖面积占全湖面积的92．9％,总生物量(湿重)为143682．4t。比较历史数据,发现湖中水生植被组成特征已由微齿眼子菜绝对优势转变为4种植物的共同优势。     

松花江哈尔滨段浮游植物群落格局及其与环境因子的相关性

松花江是黑龙江在我国境内的最大支流,流经吉林、黑龙江两省。松花江哈尔滨段是哈尔滨市工农业生产与生活用水的重要水资源,近年来由于人类活动的频繁影响,水体质量有所下降。鉴于此,于2018年春、夏、秋三季(4月、8月和10月),在松花江哈尔滨段设置14个采样点,对电导率、总氮和总磷等理化指标进行测定,同时对其浮游植物群落结构及环境因子相关性进行研究。利用群落相似性分析(ANOSIM)探讨浮游植物群落时空分布差异;通过SIMPER分析筛选出影响群落时空格局的关键物种。基于优势种和10项理化指标的冗余分析(RDA)揭示了浮游植物群落生态分布特征并对关键影响因子进行识别。研究结果表明,调查期间共鉴定浮游植物136种,其中优势种15种,群落结构主要以硅藻门和绿藻门的物种构成。松花江哈尔滨段浮游植物群落结构与过去10余年间相比较为稳定。ANOSIM和SIMPER分析表明,季节变化和人为活动干扰对浮游植物群落时空格局具有一定驱动作用,蓝藻门物种的空间分布活动干扰影响明显。RDA分析表明,浮游植物分布特征与水环境时空异质性关系密切,驱动松花江哈尔滨段浮游植物群落时空分布的主要水环境因子为电导率、总磷、浊度和pH。     

梅子垭水库生态因子场的分形特征

水生态系统由于多了一层水的介质以及水生生物较短的生命周期,使得其生态格局描述相对困难,对其进行定量描述的工作也相对较少。作为一个初步探索,分别应用非线性科学中的分形理论,对梅子垭水库的典型理化因子的生态因子场的水平的2维空间格局进行了分析,确定各浓度的稳定程度。       

面向贵州省南部新城规划的生态敏感性评价

论文建立了普适的新城生态敏感性评价指标体系, 并以此确定新城建设用地选址范围, 建议新城建设用地选址, 避开生态高敏感区, 优先选择生态敏感性较低和中等区域。针对贵州南部某新城规划区面积较小、区域潜在生态问题凸显等特点, 聚焦在生境敏感性和土壤侵蚀敏感性两类指标, 选取坡度、高程、坡向、水源保护区、土地利用、水系防护等影响因子。通过GIS 空间分析, 基于5 m×5 m 栅格, 精细表达各因子的敏感性等级分布, 并采用综合加权平均的方法计算新城规划区生态敏感性分布。结果表明, 新城规划区87.85%的区域生态敏感性高或较高。通过选址优化, 最终新城建设用地选址范围内, 生态敏感性高的区域仅占0.25%, 生态敏感性较低和中等的区域达到47.57%。     

渤海表层沉积物中砷的含量、形态、空间分布及风险评价

考察了渤海海域表层沉积物中砷的含量、分布及赋存形态，评估了沉积物中砷的生态风险，初步探讨了影响沉积物中砷分布的环境化学因子。结果表明，渤海海域表层沉积物中总砷浓度变化范围为9.77～20.60 mg·kg^-1,平均浓度为13.33±2.55 mg·kg^-1。表层沉积物中总砷的空间分布呈现出由近岸向中部逐渐递减趋势，具有西部高，东部低的特点；各个海区之间总砷含量差异显著，渤海湾和莱州湾海区表层沉积物中总砷含量相对较高。渤海表层沉积物中砷的主要形态为挥发性硫化物、碳酸盐或与无定型铁锰氧化物结合态；沉积物中砷具有一定的生态风险。渤海表层沉积物中砷含量与水体温度、磷浓度、溶解氧含量、pH、沉积物中铁含量和有机质含量呈显著的相关关系。水环境因子和沉积物的理化性质可能对沉积物中砷的分布具有重要影响。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.