广州海域潜在性富营养化特征研究

主要根据广州海洋资源环境监测中心的监测资料,运用一种反映营养盐限制特征的近海海水富营养化评价模式,对2003年广州海域富营养化水平特征进行了研究。结果表明,广州海域营养盐含量较高,无机氮浓度全年劣于国家海水水质四类标准(GB3097-1997),无机磷浓度在春夏季大部分处于三、四类水质标准之间,秋冬季则劣于国家海水水质四类标准;广州海域主要为磷限制潜在性富营养水平或磷中等限制潜在性富营养水平。同时,近二十年来,广州海域的无机磷、无机氮浓度的年平均值呈逐年增长趋势。     

象山港海域细菌的分布特征及其环境影响因素

本文于2007年的7月(夏季)、11月(秋季) 与2008年的1月(冬季)、4月(春季)用高保真、无扰动重力柱状取样器替代常规抓斗式采样,首次系统研究了象山港海域的水样(表层海水和上覆水)及沉积物中细菌丰度的时空分布特征,并采用主成分分析及多元逐步回归分析方法研究了影响细菌丰度时空分布的主要环境因素,结果表明：调查期间象山港海域的细菌的丰度较高,象山港海域的富营养化较严重。调查期间象山港海域水样及沉积物样品中细菌丰度实测值的变化范围为1.50105 ― 9.781010cells/ml (cells/g),总均值为2.76109cells/ml(cells/g);季节分布特征为夏季(7月)极显著高于其他季节,赤潮的暴发导致春季(4月)的调查结果最低。浮游细菌丰度表现为底层均大于表层的垂直分布特征;平面分布特征均为从港顶到港口递减、养殖区高于非养殖区、电厂附近海域出现较高值的趋势,近岸人类的工农业活动造成的陆源污染及海水增养殖活动造成的养殖污染是造成此分布特征的主要原因。多元统计结果表明：溶解氧、水温、营养盐(N、P)、pH以及有机质污染等是影响该海域细菌丰度的最主要因素。     

舟山海域大中型浮游动物群落时空变化及受控要素

为更好地保护舟山海域的渔业资源和生态环境,了解舟山海域浮游动物组成的时空变化,于2014年到2017年对舟山海域33个站位开展4个季节的生态综合调查,结果表明:4个航次共鉴定出浮游动物成体88种和浮游幼体19类,优势种共12种,浮游动物的优势种更替和群落特征季节变化明显,春夏、夏秋、秋冬、冬春相邻季节优势种更替率分别为75%、80%、100%和60%;平均生物量为夏季(176.34 mg/m³)>春季(120.20 mg/m³)和秋季(86.28 mg/m³)>冬季(7.21 mg/m³);平均丰度为夏季(143.97个/m³)>春季(86.30个/m³)>秋季(21.38个/m³)和冬季(26.86个/m³);平均多样性指数:夏季(3.03)>秋季(2.82)>春季(2.05)>冬季(1.71)。舟山海域浮游动物群落具有明显的季节和区域差异,温度、盐度、Chl a和营养盐是影响舟山浮游动物群落时空变化的主要环境因素,其中春季浮游动物群落空间分布主要受盐度的影响,夏季主要受温度、盐度和Chl a的影响,秋季主要受Chl a的影响,冬季主要受悬浮物和溶解氧的影响,而营养盐对每个季节的浮游动物群落分布都有一定的影响。     

黄河口及邻近海域氮、磷及环境质量评价

根据2008年和2009年5、884个航次黄河口及邻近海域监测数据,分析了该海域氮磷含量和分布,与历史数据进行比较,分析年际动态变化、营养类型,并进行有机污染和营养状态评价.结果表明:整个黄河口及邻近海域氮营养水平较高,大部分海域磷酸盐营养水平较低,营养类型为磷限制潜在性富营养;整个监测海域处于中～富营养状态,春季(5月)富营养水平稍重于秋季(8月),河口近岸海域和南部海域富营养水平较重;2008年5月和2009年8月监测海域有机污染评价为开始受污染,2008年8月和2009年5月水质较好.     

长江中游浅水湖泊水生植物氮磷含量与水柱营养的关系

水生植物组织内氮和磷(N和P)含量受到水体营养状况和植物生长状况影响。对长江中游江汉湖群不同营养水平湖泊中大型水生植物的N和P含量3个季度的研究表明,在不同生活型水生植物中,沉水植物主要分布在中营养到中富营养湖泊中,在富营养湖泊均无分布,浮叶和挺水植物在不同营养类型湖泊的沿岸带均有分布。N和P含量以沉水植物最高,浮叶植物次之,挺水植物最低。水生植物的N和P含量都达到或超过生长所需最低N和P阈值,代表性浮叶植物和沉水植物的N和P含量随着湖泊营养水平提高呈现规律性变化。湖泊5种常见的水生植物N和P含量与水柱中不同种类N和P浓度具有季节性相关:菱(TrapabispinosaRoxb.)春夏季P含量都与TP(总磷)和TDP(总溶解磷)明显相关,春季N含量与NH4—N(氨氮)明显相关;春季黄丝草(PotamogetonmaackianusA.Benn.)的P含量与TP明显相关,夏季与TDP明显相关,春季和夏季黄丝草和穗花狐尾藻(MyriophyllumspicatumL.)的N含量与TN(总氮)和TDN(总溶解氮)显著正相关,秋季成负相关;夏季芦苇(PhragmitescommunisTrin.)P含量与TP和TDP显著相关;春季芦苇和香蒲(TyphaorientalisPresl.)N含量与NH4N和NO2N(亚硝态氮)显著相关。     

基于PCA和SOM模型的龙感湖水质时空动态研究

为评估湖泊渔业模式转型阶段水环境的时空动态, 选择长江中下游典型湖泊龙感湖为研究地点, 于2017—2018年对该湖的黄梅水域和宿松水域进行周年季度水质监测, 通过主成分分析(PCA)和自组织特征映射人工神经网络(SOM)模型定量分析了水体理化参数的时空变化特征, 采用综合营养状态指数法(TLI)对水体富营养化状况进行了评价。PCA分析结果表明, 龙感湖宿松水域和黄梅水域的水质差异较小, 季节动态明显。全湖氨氮夏季平均浓度高达0.64 mg/L; 总氮夏季平均浓度为2.30 mg/L, 冬季平均浓度为1.04 mg/L; 叶绿素a夏季平均含量达95.28 μg/L, 秋季平均浓度为28.30 μg/L; pH夏季最高, 达9.27; 总磷冬季最高, 平均为0.22 mg/L; TLI指数表明龙感湖除秋季属于轻度富营养水体外, 其他3个季节均属于中度富营养状态。SOM模型结果具有可视化强的优点, 能够更清晰和直观地反映龙感湖水质的时空分布动态。围栏拆除和禁渔等管理措施有助于湖泊渔业环境修复和资源恢复, 建议对渔业模式转型后的湖泊生态系统变化进行长期跟踪监测评估。     

南沙群岛邻近海区春夏季浮游植物多样性研究

1999年春季和夏季对南沙海区网采浮游植物分布与多样性进行了调查。 1999年春季渚碧礁湖观测站及春、夏季大面站的浮游植物细胞数量平均值分别为 2 .4 9× 10 4cells/m3 、0 .73× 10 4cells/m3 和 1.0 3× 10 4cells/m3 。1999年春季在渚碧礁湖共采到浮游植物 2 6属 5 1种 ,大面站 31属 10 9种 ;夏季大面站共检出 38属 172种。海区大面站春季、夏季浮游植物Shannon Wiener多样性指数平均值分别为 4 .35和 4 .0 1;春季渚碧礁浮游植物多样性指数为 2 .92 ,低于外部开阔海域。南沙海区浮游植物的分布与水文、营养盐、浮游动物的摄食等均有一定的关系     

南麂列岛海洋自然保护区浮游植物的种类多样性及其生态分布

于2006年5月至2007年2月之间,对南麂列岛海域的浮游植物类群进行了4个季节的调查,分析了该海域浮游植物的种类组成、优势种类、群落结构以及水平分布等特征参数的季节变化。共鉴定浮游植物80种,隶属于4个门,硅藻种类最多,甲藻其次。浮游植物可划分为3个生态类群,以广温类群为主。春季和夏季分别以三角棘原甲藻和中肋骨条藻为绝对优势种,秋冬季的优势种类组成多样化。共鉴定57种赤潮生物,占浮游植物种类数的71.25%。调查期间,三角棘原甲藻和中肋骨条藻分别于春季和夏季形成赤潮。浮游植物的物种丰富度呈现春、夏、秋、冬递减的趋势。浮游植物细胞丰度的年平均值为1.03×106cells/L,春夏季显著高于秋冬季。春季和夏季时,浮游植物高值区集中在南麂岛西北近岸海域;秋季和冬季时,浮游植物高值区相对集中在南麂岛东南近岸海域。浮游植物群落的多样性指数(H')以秋季最高,冬季最低。春季的三角棘原甲藻赤潮期间,水体中N/P值显著升高;夏季的中肋骨条藻赤潮期间,水体中N/P值显著降低。     

锦州湾浮游植物群落结构特征及其对环境变化的响应

锦州湾是我国北方污染严重的海湾,以水体的富营养化和重金属污染为特征。基于2011年8月(夏季)和2012年5月(春季)在锦州湾进行的航次调查,研究了该湾水采浮游植物的群落结构、时空分布及其对生态环境变化的响应。研究结果表明:锦州湾海域浮游植物群落主要由硅、甲藻组成,其生态类型主要为温带近岸型。春季和夏季共鉴定出浮游植物4门41属62种,硅藻在两个季节的物种数和细胞丰度上均占绝对优势,且底栖硅藻比例较高。夏季浮游植物细胞丰度平均值为41.44×103个/L,主要优势种为海链藻Thalassiosira spp.和叉角藻Cerarium furca;春季浮游植物细胞丰度平均值为13.80×103个/L,主要优势种为新月柱鞘藻Cylindrotheca closterium和中肋骨条藻Skeletonema costatum。锦州湾春季和夏季浮游植物群落组成差异明显,冗余分析(Redundancy analysis,RDA)表明硝酸盐浓度和水温分别是夏季和春季影响浮游植物群落结构的最重要环境因子。与历史资料相比,锦州湾优势种发生了显著变化,适于富营养化环境的微型浮游植物和部分耐污种在群落中占优势,表明人类活动引起的水体富营养化以及其它污染物,可能对浮游植物种类组成及分布产生了一定影响。     

南黄海辐射沙脊群海域氮磷的季节变化及潜在性富营养化分析

根据2011 年5、8、10 月以及2012 年2 月对南黄海辐射沙脊群海域4 个航次海水水质的调查资料, 分析了该海水营养盐的分布特征和季节变化, 利用潜在富营养化评价模式评价水质营养状况。结果表明, 无机氮年平均浓度为0.476 mg·L1, 春季最高, 平均为0.636 mg·L1。4 个季节中溶解无机氮以硝态氮(NO3-N)为主要存在形式, 占年平均含量的76.6%, 其中以春季比例为最高, 氨氮(NH4-N)占无机氮年平均含量的23.3%, 亚硝氮(NO2-N)含量较低,全年基本未检出。磷酸盐的年平均浓度为0.164 mg·L1, 季节变化呈现春季至冬季递增的分布特征。氮和磷的空间分布基本符合由陆向海逐渐降低的趋势。本海域春季和夏季属于中度营养水平, 秋季和冬季属于氮限制中度营养水平。     

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.