大辽河水系夏季后生浮游动物群落结构及水生态评价

作为建立中国水环境生态学基准的基础性工作,于2011年6月,按照相关规范,对大辽河水系各河段的浮游动物群落结构和水生态状况进行了调查.结果表明:调查期间大辽河水系共检出59种或变种,其中以轮虫类占优势,占总种类数的84.75％,不同采样点的密度从8.63个·L-1至2292.06个·L-1不等,平均值为628.97个·L-1;主要优势种是龟甲轮虫属(Keratella)和臂尾轮虫属(Brachionus)的种类;共检出污染指示种28种,其中β-中污带指示种居多,有11种,占所有指示种的40％;Shannon指数为2.33 ～ 3.93,Margalef丰富度指数为2.84 ～ 9.42,Pielou均匀度指数为0.59 ～0.97;综合水体中后生浮游动物的密度、优势种类、指示种和生物多样性指数评价表明,大辽河水系处于富营养化状态、中等程度污染水平.相比前些年的资料,水生态状况有所好转.     

洞庭湖区平水期浮游生物群落结构特征及富营养化现状

为了解洞庭湖区浮游生物群落结构特征及其富营养化现状,于2017年8月对洞庭湖区"三口"、"四水"等来水入湖断面、湖区及出口断面等24个采样点的水质状况和浮游生物群落结构现状进行调查。结果表明:浮游植物共检出6门53属75种,平均藻细胞密度为458.3×104个·L-1,生物量变化范围为0.06~3.64 mg·L-1,平均值为0.92 mg·L-1;洞庭湖以蓝藻、硅藻占优,属于蓝藻-硅藻型湖泊;"三口水系"优势种有颗粒直链藻(Aulacoseira granulata)、科曼小环藻(Cyclotella comensis),"四水水系"优势种有颗粒直链藻、铜绿微囊藻(Microcystis aeruginosa),湖区中优势种有颗粒直链藻、铜绿微囊藻、微小平裂藻(Merismopedia tenuissima)、小席藻(Phormidium tenue);浮游动物共检出4门20属,浮游动物密度变化范围5.0~3.4×103个·L-1,"三口水系"优势属为砂壳虫(Difflugia),"四水水系"优势属为砂壳虫、铃壳虫(Tintinnidium),湖区中优势属为砂壳虫、多肢轮虫(Polyarthra)。用综合营养状态指数、浮游生物Shannon多样性指数和Margalef种类丰富度指数分别评价水体的富营养化程度,均表明洞庭湖水体呈富营养化状态。与太湖、巢湖等淡水湖泊相比,洞庭湖藻细胞密度较小,富营养化程度较浅,但从洞庭湖富营养化的历史变化趋势可以看出,洞庭湖水质状况不容乐观,对洞庭湖生态的治理和修复迫在眉睫。     

雅鲁藏布江湘河流域浮游生物群落结构的探究与多样性分析

为了探究雅鲁藏布江湘河流域生物群落结构及物种多样性现状,为西藏地区湘河流域浮游生物资源的保护及开发利用提供科学依据。本研究于2017年3～4月对湘河流域浮游生物进行了生物采样与调查,共设置采样点8个。本次调查共检出浮游植物6门61种,其中硅藻门为优势种,共41种,占总种类数的67.21%;绿藻门、蓝藻门次之,分别占总种类数的11.48%;甲藻门、隐藻门与金藻门种类较少。浮游植物密度范围为0.43×10~5～7.2×10~5cells/L,生物量范围为0.036～2.03 mg/L。共检出浮游动物3门44种,其中原生动物门为优势种,共30种,占总种类数的68.18%;轮虫13种;枝角类1种。浮游动物密度范围为1.5×10~5～1.66×10~6cells/L,生物量范围为0.9×10~(-3)～5.7×10~(-2)mg/L。各调查点浮游植物/浮游动物Shannon-Wiener多样性指数(H)和均匀度指数(E)平均分别为4.38/3.13和0.93/0.93。多项指数综合评价表明,湘河流域水质处于轻度污染或清洁状态,浮游生物群落结构单一,密度及生物量较低,生态环境较脆弱。     

长诏水库浮游植物群落结构及水质评价

于2010年5月、8月和11月对新昌长诏水库浮游植物群落进行了调查,运用Shannon多样性指数(H)、Simpson多样性指数(D)、Margalef丰富度指数(M)及Pielou均匀度指数(J)分析了浮游植物种群的多样性,并结合水质理化指标对长诏水库的富营养化程度及水质状况进行了综合评价.结果显示:长诏水库浮游植物有6门26属(种),其中,绿藻门10属(种),硅藻门9属(种),蓝藻门4属(种),隐藻门1属,甲藻门1属,黄藻门1属.浮游植物的丰度为5.73×105～7.73×105ind·L-1,平均为(6.71±0.81)×105 ind·L-1;生物量为0.73～1.03 mg·L-1,平均为(0.83±0.12) mg·L-1.在水平分布上,蓝藻门、硅藻门和绿藻门的丰度在各采样点中均较高;在季节分布上,硅藻门、绿藻门、蓝藻门分别在春季、夏季、秋季占绝对优势.总体上,浮游植物丰度和生物量在水库入水口较高,出水口较低.水库浮游植物的多样性较差,水质受到较重污染,且主要为氮、磷污染;富营养化程度为中-富营养化水平.     

以浮游植物评价达赉湖水质污染及营养水平

1987—1988年在30个样点,四季采样,对达赉湖的浮游植物进行了种类组成,生物量、种群数量、优势种、污染指示种、硅藻指数、综合指数等群落生态学的初步研究,应用后五项参数对达赉湖水质污染及营养水平进行了评价。达赉湖浮游植物年均值达54.7×106个/L(细胞数,或个体数为2.3×106个/L),硅藻指数为149.3,综合指数为5.6。群落组成中污染指示种占65%,春季以绿藻的十字藻、卵囊藻为优势种,其它3个季节均以蓝藻中的微囊藻、鱼腥藻、腔球藻占优势,表明达赉湖已受到中等程度污染,属于蓝、绿藻型富营养湖。       

东河下游指示藻类的组成及物种多样性指数分析

经过对东河下游水体的浮游藻类调查,水体浮游藻类共计5门、71属、196种,其中绿藻门占41.84%,硅藻占28.57%。从浮游植物优势分布、指示藻类和多样性指数等生物学角度分析下游水质。     

增江底栖硅藻种类多样性及分布特征

2010年1月和5月对东江水系重要支流增江进行底栖硅藻的采样调查,分析了增江流域底栖硅藻的多样性和时空分布特征,并探讨了硅藻优势种与环境因子的关系.结果表明,两次采样共检出底栖硅藻42属178种(包括亚种和变种),与1月份相比,由于5月份降雨量较大,硅藻的数量有所下降,种类组成也有所改变.在两次采样中,藻类分布从下游到...     

汉江中下游春季浮游植物群落结构特征及其影响因素

针对汉江中下游春季硅藻水华频繁暴发的现状,研究了水华暴发不同时期浮游植物群落结构特征,并结合水体理化因子分析,揭示硅藻水华发生的主要影响因子。结果表明:汉江春季水华暴发期间,共鉴定出浮游植物7门48属64种(含变种),其中硅藻种类所占比例最大(18属23种),不同样点所占比例介于44.13%~51.29%,其次是绿藻类(16属22种),不同样点所占比例介于28.21%~35.14%,蓝藻门和隐藻门种类数在水华期间较少,各样点仅发现2~3种,金藻门和甲藻门种类最少;水华发生期间主要优势种为硅藻门的小环藻,水华暴发初期和中期往往形成单优种,而水华末期随着其优势度的降低,蓝藻门、隐藻门和硅藻门其他种类也会形成优势种;水华暴发期间浮游植物密度最高可达2.34×107cells·L-1,其中小环藻种群数量最高可达2.06×107cells·L-1,占浮游植物群落总数的88%;浮游植物多样性指数中,Margalef物种丰富度指数无显著时空差异,Shannon多样性在水华中期较低,而水华初期和末期相对较高,Berger-Parker指数变化与Simpson指数相反;浮游植物与理化因子的冗余分析(RDA)发现,浮游植物总数量与磷酸盐、溶解氧、总磷呈正相关,与硝酸盐、温度、透明度呈负相关。     

三峡水库坝前水域浮游植物群落时空动态研究

于20122013 年对三峡水库坝前水域浮游植物组成、优势种、密度、生物量及多样性进行了周年季度调查, 共鉴定浮游植物151 种属, 其中绿藻门71 种, 硅藻门47 种, 蓝藻门20 种, 隐藻门和甲藻门各4 种,裸藻门和金藻门各2 种, 黄藻门1 种。浮游植物优势种的季节更替明显, 夏季和秋季优势种类为硅藻和绿藻,冬季为硅藻、蓝藻和绿藻, 春季为绿藻、硅藻和隐藻。浮游植物年均密度和生物量分别为3.95106 ind./L 和4.078 mg/L, 空间差异表现为支流和库湾远高于干流, 季节动态表现为夏季最高, 春季和冬季次之, 秋季最低。三峡水库坝前水域浮游植物多样性指数偏低, 水体污染类型属于-中污染。研究为客观了解三峡水库坝前水域浮游植物群落的空间分布与季节变化特征提供一定的参考依据。       

铜陵市河流冬季浮游植物群落结构及其与环境因子的关系

铜陵是我国重要的有色金属矿业基地,矿业开采对区域内河流生态系统生物多样性产生严重影响.2010年冬季对铜陵主要河段浮游植物群落结构进行调查,探讨其与环境因子之间的关系.结果表明:铜陵市河流生态系统中共鉴定浮游植物8门96属203种(含变种),不同河段浮游植物群落组成存在差异,但均以硅藻、绿藻和蓝藻为主;浮游植物细胞密度在9.1×103～6.5×107 cells·L-1,直接承接矿业废水河段细胞密度明显低于未直接承接矿业废水河段;各采样点Shannon物种多样性指数为0～3.45,不同河段存在显著差异.浮游植物密度及属类数与CODcr、Cd、Cu和Zn呈显著相关性,全氮(TN)、NH4+-N、NO3--N浓度以及CODcr、pH和Cu是影响该区域河流浮游植物物种分布的重要因素.尽管水体营养状况对浮游植物的影响大于重金属,但来自矿山企业的重金属对其群落结构的影响也不容忽视.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.