基于等级模型的考洲洋石油烃污染状况

通过等级模型的创建,在G IS的支持下,对1999年2月(枯水期)和8月(丰水期)考洲洋表层海水和表层沉积物的石油烃水平进行了综合的分析和评价。枯水期湾内表层海水的石油烃含量为0.036~0.060m g/L,水平为2~3级,已受到一定程度的石油烃污染;丰水期表层海水的石油烃含量均低于0.050m g/L,为1~2级水平,整个水域石油烃污染程度较轻。枯水期湾内表层沉积物石油烃含量的变化范围较大,为16.0×10-6~657.0×10-6(干重),处于1~3级水平,其中湾中部至北部沿岸大部分水域表层沉积物的石油烃水平相对较高,为2~3级水平,表明该片水域表层沉积物已受到一定程度的石油烃污染;丰水期湾内表层沉积物的石油烃污染程度较枯水期轻,整个水域的石油烃含量均低于500.0×10-6(干重),其中除吉隆河口附近水域的含量稍高,为2级水平外,其余绝大部分水域均为1级水平。通过G IS的加权运算,分别将表层海水和表层沉积物的石油烃水平进行综合的分级评价,评价结果显示考洲洋石油烃的综合水平在2个调查季节的变化趋势分别与表层沉积物石油烃的变化趋势极为相似,调查期间整个水域石油烃的综合污染水平较低,为1~2级水平。2个调查航次相比,表层海水和表层沉积物石油烃平均含量均为枯水期>丰水期。而从各个站位石油烃的含量水平来看,除个别站位外,绝大多数站位表层海水和表层沉积物石油烃含量的季节变化趋势均表现为枯水期>丰水期。     

考洲洋饵料生物水平综合评价

在GIS(Geographical Information System)的支持下,利用等级模型对1999年2月(枯水期)和8月(丰水期)考洲洋饵料生物水平进行了综合的分析和评价。枯水期考洲洋整个水域饵料生物的分布较均匀,其密集分布区位于湾西北部、湾口和吉隆河口附近水域,达4级水平,饵料生物较为丰富。丰水期饵料生物水平的变化幅度较大,其密集分布区位于湾中部和望京洲沿岸水域,达4-5级,饵料生物最为丰富,其次为湾口,达4级水平。两个调查航次相比,丰水期的饵料生物水平高于枯水期。主要优势种的变化具有明显的季节交叉和演替现象,浮游植物和浮游动物的主要优势种在不同季节差异较大,而底栖生物的优势种组成在整个调查期间变化不大。调查期间各饵料生物的多样性指数和均匀度均呈现出较大的变化,其最大变化范围分别为0.01-4.49和0.01-0.96,表明湾内饵料生物受外界环境条件影响较大,生物群落组成结构和生物多样性水平不太稳定。调查期间整个水域的生物多样性阈值均呈现出湾西部及西北部水域较高,其余水域较低的分布特点,但不同季节其变化趋势及分布范围略有差异。枯水期多样性阈值的密集分布区出现于湾西侧的部分水域,其等级水平为3级,饵料生物多样性较好,其余水域均为2级或低于2级水平,多样性一般或较差。丰水期的分布趋势与枯水期相似,其密集区出现于湾西部和西北部的整片水域中,分布范围比枯水期大,但等级水平明显低于枯水期,为2级,多样性一般,其余大部分水域均为1级水平,多样性较差。       

汕头湾表层沉积物重金属污染与潜在生态风险评价

汕头湾作为华南地区重要的出海门户,汕头市主要的旅游区和水产养殖基地,其环境污染问题已成为制约当地经济发展的重要因素,为此2002年在此开展了重大科技术兴海项目,以海洋沉积物质量标准、单因子污染指数和潜在生态风险评价体系对汕头湾表层沉积物重金属污染现状和潜在生态风险进行了评价。结果表明:汕头湾表层沉积物中Cd,Cu,Pb,Zn的平均含量超过海沉积物质量标准(Ⅰ类);以单因子污染指数评价,Cd达到很强污染等级,Zn为强污染,Cu,Ni,Pb为中等污染;以单元素生态系数(E_rⁱ)评价,只有Cd的潜在生态风险达到很强等级,其它元素则只属于轻微潜在风险范畴;以多元素潜在生态风险指数(RI)评价,汕头湾的潜在生态风险水平处于中等强度;重金属含量分布特征与重金属污染及潜在生态风险的空间差异性一致,表现为由上游至下游呈波状递减趋势,其中以牛田洋和汕头港上游最为严重;这一污染特征主要是由集水区域内的产业结构特点、河流入海口及排污口的分布以及汕头湾的地理和水文特性所决定的。     

GIS支持下考洲洋养殖水域浮游植物数量的时空分布及其与营养盐的相关性研究

在GIS和统计分析软件SPSS的支持下,利用数据插值、相关性分析和回归分析等方法,研究了枯水期和丰水期考洲洋养殖水域浮游植物数量的分布趋势及其与海水营养盐的相关关系。结果表明,枯水期浮游植物数量的分布较为均匀,其密集区分布于吉隆河口及其附近水域;而丰水期的数量变化幅度较大,密集分布区出现在湾口至盐洲岛北部水域,呈现出从湾西北部至湾口水域逐渐增加的分布趋势。两次调查相比,丰水期浮游植物的数量明显高于枯水期。相关性研究结果表明,调查期间浮游植物数量与无机氮和无机磷的相关性均不显著,但与活性硅酸盐呈显著相关,在枯水期两者之间呈显著正相关,而在丰水期则刚好相反,两者之间呈显著负相关。     

青山水库表层沉积物重金属污染特征及生态风险评价

在位于浙江省临安市的青山水库采集了具有代表性的8个样点的表层沉积物样品,分析比较了样品中As、Cr、Cu、Ni、Mn、Pb、Zn等7种重金属总量的差异,采用BCR连续提取法对重金属不同形态(酸提取态、可还原态、可氧化态、残渣态)进行分析.采用地积累指数法(I_geo)和Hakanson潜在生态风险指数法,对青山水库不同采样点表层沉积物中重金属的污染程度和潜在毒性与生态风险进行评价.结果表明: 青山水库表层沉积物重金属污染程度存在明显的空间差异,流经城区和工业园区的青山水库支流入库河口附近的表层沉积物重金属含量明显高于其他采样点.青山水库表层沉积物7种重金属中,Mn主要以酸提取态存在;Cu和Pb主要以可还原态形式存在;As主要以残渣态形式存在.流经城区的支流入库河口附近表层沉积物还原态和酸提取态重金属比例较高,对水生生物有一定的毒性风险.8个样点的表层沉积物7种重金属中,以As污染程度最高,潜在生态风险最大,其次是Cu、Ni、Mn、Pb和Zn,均处于轻度污染状态,而Cr处于清洁水平,潜在生态风险较低.不同采样点比较发现,分别流经城区的锦溪和工业园区的横溪入库河口附近表层沉积物重金属污染程度和潜在生态风险明显高于其他采样点.     

基于突变理论的近岸海域生态风险综合评价方法——以罗源湾为例

基于突变理论建立了“海水水质-沉积物-生物体”三相一体、“富营养化-重金属-有机污染”3种类型的近岸海域生态风险综合评价指标体系和递级突变模型,综合相关质量标准,建立了近岸海域生态风险4级评判标准（无、低、中、高）,采用2007和2009年监测数据对罗源湾进行生态风险综合评价.结果表明： 2007-2009年,罗源湾生态风险空间变化特征表现为从湾顶到湾口呈降低趋势;2009年罗源湾生态风险等级总体小于2007年;罗源湾关键生态风险因素为富营养化.本文所建方法能够识别近岸海域生态风险的时空变化特征,能较好地反映出关键风险因素,为近岸海域生态风险有效预测预警提供了基础方法.     

大亚湾表层沉积物和底栖生物中重金属的污染特征与生物积累

通过分析2015 年5 月大亚湾海域34 个采样站位表层沉积物和底栖生物生物体中5 种重金属(铜、铅、锌、镉、汞)的综合污染程度因子、潜在生态风险因子和生物-沉积物积累因子, 评估了大亚湾海域表层沉积物重金属的污染现状、潜在生态风险水平和生物-沉积物积累程度。结果表明: 大亚湾海域表层沉积物中重金属含量上呈现锌>铅>铜>镉>汞的规律; 空间上呈带梯度带分布: 北部沿岸海域含量较高, 南部口门附近海域最低。重金属污染属于中等-比较严重污染水平, 其中锌、镉、汞是大亚湾沉积物污染的主要因子, 潜在生态风险属于中等-较高风险水平, 汞、镉是较大的潜在风险因子。底栖生物生物体重金属含量上呈现锌>铜>铅>镉>汞。铜、铅、锌、汞四种重金属除铜、锌在棒锥螺(Turritella terebra)生物体轻度积累外, 其它均无明显积累表现, 而重金属镉呈现较强的积累现象。     

大亚湾及邻近海域重金属污染的研究进展

综述了大亚湾及其邻近海域的海水、沉积物以及生物体中重金属的浓度水平、赋存形态、时空分布以及潜在生态风险等的研究进展。现有的研究表明, 大亚湾海域海水中重金属污染程度较轻, 但部分海域的Cu、Pb、Zn 有超标现象; 沉积物中重金属主要为残渣态, 污染程度较轻, 重金属含量呈增加的趋势, 尤其是Hg、Cd 的潜在危害较高;海产品中重金属浓度水平较低, 但底栖生物中Cd 含量水平存在一定的生态风险。综合现有研究资料, 大亚湾海域有机重金属化合物的污染状况研究, 同位素示踪技术分析重金属来源以及膜扩散梯度技术等在大亚湾重金属污染调查中的应用等方面仍需要进一步开展。     

厦门杏林湾表层沉积物重金属污染特征及潜在生态风险评价

论文对杏林湾表层沉积物重金属、有机碳和硫化物含量进行了检测,对数据作了相关性分析和因子分析,并应用潜在生态危害指数法对重金属的潜在生态风险进行了评价。结果表明:重金属之间有显著的相关性,Cu与Ni、Pb与Ni、Pb与Cr以及Cr与Hg之间的相关系数分别为0.786(P﹤0.05)、0.783(P﹤0.05)、0.937(P﹤0.01)和0.770(P﹤0.05)。重金属与有机碳及硫化物的相关性较差,表明该地区重金属污染来源与硫化物和有机碳并不相同。既有人为输入,又有自然的沉积过程。因子分析进一步解释了该水域重金属污染的主要来源。根据E_rⁱ均值大小,Hg的危害风险最大,Cr最小。6种重金属潜在生物毒性风险大小依次为:Hg > Pb > Cu > Cd > Ni > Cr。重金属的生态危害程度均较小,尚属轻微生态危害。     

北京市南沙河沉积物重金属污染特征及风险评价

北京南沙河是海淀北部地区的重要排水和风景观赏性河道,为全面了解南沙河底泥沉积物中重金属的污染特征,采集了表层沉积物样品,分析了重金属元素的含量和形态,并利用单因子指数法、Hakanson综合污染指数法和潜在生态风险指数法对沉积物重金属进行了生态风险评价.结果表明:南沙河表层沉积物各种重金属元素存在较好的同源性,污染程度为:Cr＞Cd＞Zn＞Cu＞Pb＞Ni.基于单项潜在生态风险指数的评价表明,该区域重金属生态风险等级由强至弱依次为:Cd＞Pb＞Cu≈Cr＞Ni≈Zn,其中,仅Cd具有较高的潜在生态风险,综合潜在生态风险指数表明,除了京藏高速桥河段危害等级较高外,南沙河总体处于轻微的生态风险等级.形态分析表明,Cd的酸提取态含量高,迁移性最强,最容易对生物造成直接危害,其次是Pb和Zn,Cu和Ni具有一定程度的潜在环境危害,Cr产生环境危害的可能性较小.     

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.