Sensitive and rapid detection of two toxic microalgae Alexandrium by loop-mediated isothermal amplification

A loop-mediated isothermal amplification (LAMP) assay was designed and evaluated for rapid detection of the toxic microalgae Alexandrium catenella and A.minutum,which can produce paralytic shellfish poisoning (PSP).Two sets of four specific primers targeting these two species were derived from the sequence of internal transcribed spacer (ITS) of ribosomal DNA.The method worked well in less than an hour under isothermal conditions of 65 C.LAMP specificity was validated in closely related algae as a comparison,suggesting the strict specificity of the LAMP primers.Two visual inspection approaches were feasible to interpret the positive or negative results.The detection limits of A.catenella and A.minutum samples using the LAMP assay were found to be 5.6 and 4.5 pg DNA,respectively.The sensitivity of this LAMP assay was 10 or 100-fold higher than Polymerase Chain Reaction (PCR) method in detecting the two microalgae.These characteristics of species specificity,sensitivity,and rapidity suggest that this method has the potentiality in the monitoring of red tide caused by A.catenella and A.minutum.     

基于环境DNA宏条形码技术的赣江下游(南昌段)鱼类多样性

随着人类活动对自然生态系统的负面影响不断加剧,无创性生物多样性评估变得越来越重要。本研究旨在利用环境DNA宏条形码技术研究赣江下游南昌段鱼类多样性,并从不同季节（春、夏、秋、冬）、不同水层（上层、中层和下层）和不同取样位置（近岸和离岸）比较鱼类环境DNA信息的物种组成和多样性。结果表明：利用环境DNA宏条形码技术在赣江下游南昌段检测到鱼类114种,其中83种为历史记录种。不同季节的鱼类环境DNA信息的多样性和组成显示出极显著差异。上层水检测到的鱼类物种数分别显著多于中层水和下层水,且中层水和下层水检测到的鱼类在上层水中绝大多数都被检测到。上层水、中层水和下层水的鱼类环境DNA信息的多样性和组成不具有显著性差异。近岸检测到鱼类物种数多于离岸的,鱼类多样性指数无显著性差异,但群落结构具有显著性差异。RDA分析表明,赣江下游鱼类环境DNA受温度和pH的影响较大。本研究能够为基于环境DNA宏条形码的赣江鱼类资源的调查提供基线数据,并对后续赣江鱼类资源环境DNA宏条形码监测实施不同目的的采样策略提供依据;可为使用环境DNA宏条形码技术研究流水系统鱼类多样性提供技术参考,为环境DNA宏条形码技术应...     

Genetic and morphological evidence for a single species of pink ling (Genypterus blacodes) in New Zealand waters

Two species of ling, Genypterus blacodes (Forster in Bloch & Schneider, 1801) and G. microstomus (Regan, 1903) have been recorded from New Zealand and Australian waters; a third species, G. tigerinus (Klunzinger, 1872) has been recorded from Australia. Specimens of ling collected from northern, central, and southern localities in the New Zealand Exclusive Economic Zone (EEZ), and specimens of G. blacodes from Australia were shown to be similar with respect to partial sequences of mitochondrial (mt)DNA, and morphometric and meristic characters. DNA sequences of part of the cytochrome b and control region showed that G. blacodes from Tasmania and New Zealand differed by 1/291 and 4/284 nucleotides respectively, but there was much greater genetic differentiation between G. blacodes and G. tigerinus (14/291 and 14/284 nucleotides), and between G. blacodes and G. capensis (23/291 and 8/284 nucleotides). MtDNA haplotypes within New Zealand show that G. blacodes is subdivided into northern and southern stocks. It is concluded that ling in New Zealand represent a single species referable to G. blacodes, and that G. microstomus Regan is a junior synonym.     

Morphological and molecular diagnoses of Polydora brevipalpa Zachs,1933(Annelida: Spionidae) from the shellfish along the coast of China

Shell-boring species Polydora brevipalpa Zachs, 1933 is redescribed based on morphological observations and molecular approach for future unambiguous identification. Genetic distance analyses showed that the interspecific polydorid variation (16.7%–25.6%) was at least 15 times higher than the intraspecific one (0.2%–0.9%) based on the cytochrome c oxidase subunit I (CO1) gene sequences of polydorids. However, 18S rDNA variation pattern demonstrated a rather narrow barcoding gap, with the interspecific polydorid variation (0.5%–5.6%) being very close to the intraspecific one (0.0%–0.4%). As such, the CO1 gene exhibited better DNA barcode for identification of polydorids than the 18S rDNA gene because of the sufficiently large barcoding gaps. Analysis of molecular variance results based on CO1 gene sequences showed that most variations in sequences (97.79%) lay within groups of adult worms and egg capsules rather than between them. This indicated that egg capsules from Crassostrea gigas (Thunberg, 1793) in Ningbo and Nantong were related to the adult worms from Patinopecten yessoensis (Jay, 1857) in Dalian, and both of them belonged to P . brevipalpa . This result was further supported by parsimony network analysis, which showed that egg capsules collected from diff erent localities and adult worms shared a single haplotype. This study was the first to report both P . brevipalpa infestation on C . gigas and to utilise the known CO1 sequences of the adult polydorids to validate morphologically unidentified egg capsules or early larvae. P . brevipalpa was most possibly brought to Chinese waters through transportation of Pa . yessoensis brood stock from Japan.     

Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina

Advancements in ancient DNA analyses now permit comparative molecular and morphological studies of extinct animal dung commonly preserved in caves of semiarid regions. These new techniques are showcased using a unique dung deposit preserved in a late glacial vizcacha (Lagidium sp.) midden from a limestone cave in southwestern Argentina (38.5° S). Phylogenetic analyses of the mitochondrial DNA show that the dung originated from a small ground sloth species not yet represented by skeletal material in the region, and not closely related to any of the four previously sequenced extinct and extant sloth species. Analyses of pollen and plant cuticles, as well as analyses of the chloroplast DNA, show that the Cuchillo Curá ground sloth browsed on many of the same herb, grass, and shrub genera common at the site today, and that its habitat was treeless Patagonian scrub-steppe. We envision a day when molecular analyses are used routinely to supplement morphological identifications and possibly to provide a time-lapse view of molecular diversification.     

太平洋牡蛎( Crassostrea gigas )不同组织DNA相对含量及细胞周期的分析

以太平洋牡蛎(Crassostrea gigas)为试验材料,应用流式细胞仪分别测定常温下(16℃)和0℃低温下鳃、外套膜、性腺(包括2个取样部位)的DNA相对含量并分析各组织细胞周期各时相的差异.试验结果表明,常温下(16℃)牡蛎不同组织DNA相对含量的顺序依次为性腺取样部位2＞外套膜＞鳃＞性腺取样部位1,性腺取样部位1的DNA含量低于前三者(P＜0.05);在0℃低温处理后,牡蛎各组织的DNA含量有所下降,随着低温处理时间的延长,鳃组织的DNA含量变化不显著(P＞0.05),外套膜的DNA含量显著减少(P＜0.01),性腺组织的显著增加(P＜0.01);常温下牡蛎各组织细胞停留在G1期时相的比率依次为性腺取样部位2＞鳃＞外套膜＞性腺取样部位1;在0℃低温处理下,鳃与外套膜之间停留在G1期比率差异不显著(P＞0.05),其余各组织间G1期比率差异均极显著(P＜0.01),对于同一部位,随着0℃持续时间不同,鳃、性腺取样部位2处于G1期时相比率的变化不显著(P＞0.05),外套膜和性腺部位1的变化显著;与常温下相比,0℃处理性腺取样部位1,2后,二者停留在G1期时相的比率均显著增加(P＜0.01).     

The Biodiversity of Shrimp Genus Artemia from Russian Lakes:Morphometric,Cytogenetics and DNA-analysis

正Shrimps of genus Artemia are the inhabitants of continental and marine waters with salinity of 70 to 350 g/l and above.Artemia is able to survive in the conditions in which other animals cannot exist.This is due to adaptations:effective osmoregulation system,the ability to synthesize of respiratory pigment(hemoglobin)and diapauses cysts(Litvinenko at.al.,2009).Cysts of this     

福建省沿海鱚属（Sillago）鱼类新纪录种——中国鱚（Sillago sinica Gao and Xue,2011）

本研究报道了在福建省晋江和厦门近海采集到的新记录种——中国鱚,将其分布区向南延伸至福建省沿海,并对采集到的中国鱚进行形态特征的重新描述,及扩增其DNA条形码.中国鱚的主要鉴别特征为：第一背鳍鳍膜具不规则的、呈弥散状的黑色斑点,由前往后逐渐稀疏;第二背鳍沿鳍条具3～4行规则的黑色斑点;侧线上鳞数为6～7;脊椎骨数为37～39.结合Gen Bank中鱚属鱼类的同源序列进行比对研究,结果显示本研究采集到的中国鱚与中国鱚模式种聚类到一起,并与其余种类明显分开,在遗传距离和氨基酸水平上与其他种类产生了明显地分化,进一步证明了DNA条形码能高效快速的鉴别鱚属鱼类.本研究为鱚属鱼类分类与研究提供理论基础,通过调查发现中国鱚主要分布在有大量淡水注入的河口区,南至韩国光阳沿海,北至中国福建省沿海,数量较少并不能形成渔汛.     

企鹅珍珠贝非致死性DNA提取方法的研究

在企鹅珍珠贝遗传育种研究中,为保证在贝类存活的条件下获得其DNA信息,采用企鹅珍珠贝(Pteria penguin)贝壳边缘和足丝研究非致死性DNA提取方法。不同于贝壳获取过程中会对实验贝体产生一定损伤,足丝是无生命的细胞外纤维束,其获取方法简单且属于非损伤性取样,对实验贝几乎无伤害,是潜在的获取具足丝贝类基因组DNA的优良材料。本研究采用脱钙与未脱钙两种处理方式,并结合海洋动物组织基因组DNA提取试剂盒法及有机溶剂萃取法(OSE)提取贝壳及足丝DNA,对获得的贝壳DNA及足丝DNA进行PCR扩增。结果显示,足丝有机溶剂法(OSE法)提取效率显著高于贝壳DNA提取方法,脱钙足丝与未脱钙足丝的DNA提取效率无显著差异,分别为(0.016 7±0.002 9)μg/mg和(0.016 1±0.003 1)μg/mg。未脱钙足丝的OSE法获得的DNA产物纯度最优, A260/280值为1.400 0±0.040 0,A260/230值显著高于贝壳DNA及足丝DNA的其他提取方法,为0.910 0±0.080 0。除脱钙贝壳OSE法外,其他所有DNA提取方法均可用于后续PCR扩增,测序结果表明...     

慢性氨氮胁迫对鲻鱼(Mugil cephalus)幼鱼组织细胞免疫指标的影响研究

以鲻鱼(Mugil cephalus)幼鱼为研究对象,研究低浓度氨氮长时间胁迫对组织细胞免疫指标和遗传物质代谢的影响。实验分0.35、0.7、1.5和3mg/L氨氮处理组,分别于0、5、10、15、20d取样并进行相关指标测定。结果显示:肝脏和鳃丝的丙二醛(MDA)含量表现出先上升后下降的趋势,MDA活性与氨氮浓度呈一定的正相关。氨氮对MDA的影响具有不同组织和不同时序的选择性。不同浓度氨氮胁迫下,鳃丝和肝脏Na+-K+-ATP活性均呈现先升高后降低,并随着时间的增加逐渐趋于稳定。Na+-K+-ATP活性与氨氮浓度呈一定的负相关性,尤其是3mg/L处理组与对照组差异性显著(P0.05)。在氨氮浓度0.7mg/L和1.5mg/L时,肌肉中RNA/DNA均表现出不同程度的增加,各浓度组与对照组差异不显著;而高浓度(3mg/L)比值基本无变化。肝脏和鳃丝的Na+-K+-ATP酶的mRNA表达量,在氨氮胁迫第5d时检测到达最高,随后表达量缓慢回落,实验20d除3mg/L处理组表达量仍高于对照组水平外,其他处理组均降至对照组水平。Na+-K+-ATP酶的表达水平变化趋势与Na+-K+-ATP活性基本一致。结果表明,在一定浓度的氨氮长时间胁迫作用下,抗氧化免疫系统和肌肉中的核酸代谢受到了一定的影响。