利用PCR方法研究广州市景观湖产毒微囊藻的季节分布特点

为研究景观水体中产毒微囊藻的季节性分布特点,利用针对蓝藻和微囊藻的16srDNA、微囊藻毒素合成酶 mcyB 基因的部分核苷酸序列设计和筛选的特异性引物,对广州市内8个景观湖108份水样进行了冬季、夏季和秋季的二重及套式PCR的检测。结果显示,在冬季能被检测出的产毒微囊藻的阳性水样为42份,夏季为102份,而秋季为100份;阳性率分别为38.9%、94.4%、92.5%,产毒微囊藻在夏季和秋季阳性率高。结果表明在冬季、夏季和秋季均有产毒微囊藻分布;夏、秋季是广州市景观水体微囊藻污染的高峰季节,值得引起水文部门足够的重视。     

微囊藻毒素合成酶基因的PCR检测方法

针对微囊藻毒素合成酶基因簇的核酸序列,筛选特异性引物,探索一种适用于自然水样中微囊藻产毒潜能检测的全细胞PCR方法。经灵敏度测试表明,这种PCR方法的检测下限相当于100cells。该方法不需要提取基因组DNA,检测所需水样量少,具有操作简便、快速、成本低、灵敏度高等优点,能应用于水库等饮用水源水体中具有产毒潜能的微囊藻的检测。     

阿氏浮丝藻mcyT基因序列多样性研究

为研究我国浮丝藻（Planktothrix Anagnostidis et Komrek）的毒素相关基因,选取分离自我国不同省份水体的13株阿氏浮丝藻,通过PCR检测其微囊藻毒素合成酶基因mcyA、mcyE及mcyT研究其毒素基因特性。PCR结果表明除mcyT之外其他引物检测均无扩增产物,说明这13株浮丝藻不具备产微囊藻毒素的能力。通过克隆测序得到mcyT序列,并进行分子系统分析,构建了关于mcyT序列的Neighbor-Joining系统树,结果表明mcyT序列可以将产毒与不产毒浮丝藻分为两大独立的分支,两个分支之间的最低序列相似度分别为98.5%和99.1%。研究结果可为后续研究我国浮丝藻的微囊藻毒素合成相关基因的多样性以及分子监测提供参考。       

利用3对引物鉴定产毒和非产毒微囊藻

根据微囊藻毒素合成酶基因簇序列 ,合成了 3对引物epF/mb1R ,mcF/teR ,mcF/umR ,通过全细胞PCR的方法检测了 19种不同来源微囊藻产毒的情况。 3种引物对 15株产毒微囊藻中均可扩增到预期大小的片段 ,测序结果证明这些片段是微囊藻毒素合成酶基因片段。PCR反应结果与HPLC分析所得到的结果有良好的对应性。在此基础上 ,初步确定了 3对引物检测产毒微囊藻对细胞浓度要求的下限。与其它引物相比 ,3对引物的特异性强 ,扩增条带大小适中 ,便于观察     

全细胞多重PCR检测蓝藻、微囊藻及产毒微囊藻方法初探

选取三对分别针对微囊藻、蓝藻16S rDNA及微囊藻毒素合成酶基因mcyB的保守序列的特异性引物209F/409R、27F1/409R、MTR/MTF,其中409R为一条共用引物。设计并优化了一种可以同时检测蓝藻和微囊藻的两重全细胞PCR方法和一种可以同时检测蓝藻、微囊藻和可产毒微囊藻的三重全细胞PCR方法,并且测试了这两种PCR反应的灵敏度区间,分别为10⁵～10³cell·mL^-1、10⁵～10²cell·mL^-1。对采集水库水样检测结果表明双重全细胞PCR方法可以直接应用于对天然水样的检测,三重全细胞PCR方法可用于实验室培养藻细胞的筛查。全细胞多重PCR方法具有快速、简便、准确等特点,在水体微囊藻毒素检测预警方面具有应用价值。     

广东省水库微囊藻的产毒特征和ITS序列的遗传多样性分析

为了解广东省水库微囊藻的产毒特征和ITS 序列的遗传多样性,从广东省供水水库中分离得到28 株微囊藻(Microcystisspp.),对它们的产毒特征和15 株微囊藻的ITS 序列进行了分析.高效液相色谱(HPLC)和微囊藻毒素合成酶基因mcyE 的检测结果表明,广东省水库中的微囊藻以产毒藻株占优势,微囊藻毒素的主要类型为MC-RR.广东省15 株藻株的ITS 序列相似性大于93.2%,在用相邻法(NJ)构建的系统树上,不同形态的种和不同地理区域的藻株没有区分开,产毒和非产毒藻株没有形成独立分支.这说明微囊藻ITS 序列的遗传多样性较低,ITS 序列和mcyE 存在没有相关性,表型不能够反映藻株的进化关系.因此,有必要将藻类传统分类方法与分子方法结合起来对蓝藻进行重新分类.     

一种快速检测微囊藻毒素mcyG基因的新技术——环介导恒温扩增

利用环介导恒温扩增(LAMP)技术,以微囊藻毒素(Microcystins,MCs)合成基因簇中的mcyG基因为靶序列,设计了1 套LAMP引物,建立了LAMP反应体系并进行灵敏度和特异性实验。结果表明mcyG基因的最低检测限为:24 cfu/mL,远低于常规PCR(Polymerase Chain Reaction)。整个检测过程仅需40 min,且可直接目测结果。特异性实验中, 13 株淡水常见水华蓝藻分属:色球藻属(Chroococcus)、念珠藻属(Nostoc)、鱼腥藻属(Anabaena)、束丝藻属(Aphanizomenon)、微囊藻属(Microcystis),其中10 株呈阳性反应, 3 株为阴性。在野外样品检测中,来自太湖与黄庆苗池塘的水样PCR检测显示阴性反应,而LAMP检测均呈阳性反应,提示此两处水样中可能含有产毒微囊藻,显示出了LAMP检测方法良好的野外检测和预警能力。综合上述,LAMP检测方法能够快速检测产微囊藻毒素的关键基因,且结果可视化。该方法简便、快捷、不依赖特殊检测设备,极具推广前景。     

水华蓝藻产毒特性的PCR检测法

特异引物对（TOX 1P／1F;TOX 2P／2F）用于检测微囊灌毒素合成酶基因mcyB片段在38种水华蓝藻中的分布情况。结果显示,所有能产生微囊灌毒素的微囊藻都有特异扩增条带,非产毒株则没有,几种常规的毒性检测方法验证了PCR方法所获结果的准确性。本研究发展了以全细胞PCR法检测mcyB片断,说明全细胞PCR检测法适用于不同来源的蓝藻材料。结果证明以DNA为基因鉴别产毒和非产毒微囊藻及其他水华蓝藻的方法是可行的和实用的。     

广东省典型大中型供水水库和湖泊微囊藻毒素分布

为了解肝脏促癌剂微囊藻毒素（MCs）在广东省淡水水体中的污染情况,于2003年夏、秋、冬3个季节,采集了广东省12个典型供水水库和4个湖泊的水样;同时于2004年2—12月对7个水库和1个湖泊进行了每隔2个月的加密调查,用高效液相色谱（HPLC）和酶联免疫法（ELISA）测定了水体中微囊藻毒素（MCs）含量。结果显示广东省典型供水水库和淡水湖泊微囊藻毒素分布广泛,毒素组成以MC-RR为主,水库微囊藻毒素含量在未检出—0.919μg/L,2004年毒素含量比2003年有一定程度的上升。微囊藻毒素污染较为严重的水库为汤溪、鹤地、契爷石和深圳等水库,广州流花湖和肇庆星湖等城市景观湖泊中微囊藻毒素污染也较为严重。虽然本次调查的所有水样MCs含量均在世界卫生组织和我国饮用水卫生标准以下,但结果说明广东省饮用水源已在一定程度上遭受MCs的污染,需采取有效措施防止水质进一步恶化。     

淡水鱼类微囊藻毒素去毒酶基因的克隆

微囊藻毒素去毒酶在鱼类微囊藻毒素去毒过程中起着关键作用,研究成功克隆鲢鱼、鳙鱼、草鱼、鲫鱼、鳜鱼、罗非鱼等淡水鱼类微囊藻毒素去毒酶基因cDNA核心片段而首次获得这些淡水鱼类微囊藻毒素去毒酶氨基酸序列。鲢鱼、鳙鱼、草鱼、鲫鱼、鳜鱼、罗非鱼微囊藻毒素去毒酶基因与人、小鼠、大鼠、牛、猪、羊的谷胱甘肽S-转移酶基因氨基酸同源性为60%左右,表明淡水鱼类微囊藻毒素去毒酶基因在进化上变异性较大,与其承担微囊藻毒素去毒代谢之特殊功能相适应。     

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     

Comparison of in vitro decomposition of bryophytic and tracheophytic plant material

The fossil record of bryophytes is generally poor and infertile plants attributable to liverworts and mosses could also be thalloid vascular plant gametophytes or herbaceous lycophytes respectively. The paucity of the bryophytic record could be the result of relatively rapid degradation of bryophytic material in comparison to that of vascular plants, the absence of lignified cells in bryophytes sustaining this belief. However, certain organs of bryophytes are as robust as those of vascular plants (e.g. spores) and the hydroxybenzofuran polymers produced by some mosses could be of similar preservational resistance to lignins. A simplistic experiment to test the relative resistance to decay of bryophytic material has been undertaken. Its findings suggest that bryophytic plant material has a similar preservational potential to that of a selected vascular plant, particularly in organic rich sediments. This result may be construed to imply that bryophytes were indeed less abundant in the preservational environments of the Coal Measures than might be expected on the basis of current palaeoenvironmental reconstructions.     

Epidemiological,Clinical and Serological Characteristics of Children with Coronavirus Disease 2019 in Wuhan: A Single-centered,Retrospective Study

In December 2019, SARS-CoV-2 was first detected in the samples obtained from three adult patients who suffered from an unknown viral pneumonia in Wuhan (Li et al. 2020). This unknown viral pneumonia is further named as coronavirus disease 2019 (COVID-19) by the World Health Organization. To date, the number of new COVID-19 cases has continued to skyrocket and the impact of SARS-CoV-2 on humans is far greater than any pathogen of this century in both breadth and depth. Previous studies have shown that adults with COVID-19 have symptoms of fever, dry cough, dyspnea, fatigue and lymphocytopenia. Moreover, COVID-19 is more likely to cause death in the elderly, especially those with chronic comorbidities (Huang et al. 2020). In Wuhan, more than 50, 000 COVID-19 cases have been confirmed, including over 780 pediatric patients, and only one child death case (Lu et al. 2020). Although the number of children cases was far fewer than that of adults, COVID-19 might endanger children's health and the information on children remains limited, especially in serological study. In the retrospective study, the investigators analyzed the epidemiological, clinical and serological characteristics of children with COVID-19 in Wuhan in the early stages of the outbreak, which might provide theoretical and practical help in controlling COVID-19 and similar emerging infectious diseases in the future.