近江牡蛎SLC13基因家族的全基因组鉴定及急性高盐胁迫下的表达特征

溶质载体13(solute carrier 13, SLC13)是SLC转运蛋白超家族的重要成员,编码结构相似的跨膜蛋白,在介导转运阴离子和柠檬酸循环代谢中间体中发挥重要作用。近江牡蛎(Crassostrea ariakensis)基因家族收缩和扩张分析表明,SLC13家族显著扩张,可能与渗透压调节密切相关。为进一步探讨近江牡蛎SLC13基因家族(CarSLC13)特征及在高盐胁迫下的表达变化,本研究运用生物信息学方法对CarSLC13进行鉴定,并分析了其基因结构、染色体定位、系统进化和在急性高盐胁迫后鳃组织中的表达特征。本研究共鉴定出11个CarSLC13基因,包括1个CarSLC13A1亚家族成员, 6个CarSLC13A2亚家族成员和4个CarSLC13A5亚家族成员,其中7个家族成员蛋白的理化性质较为稳定,不稳定系数均小于40;亚细胞定位预测显示,所有CarSLC13均定位到细胞膜或内膜;染色体定位结果显示, 11个SLC13基因定位在6条染色体上,在第3号染色体上的部分基因发生了串联复制;该基因家族成员都具有钠-硫酸盐共转运蛋白跨膜结构域(PF00939),该结构域与渗透压调...     

鲤和草鱼IL17受体基因家族的全基因组识别、起源进化及表达分析

为了研究鲤科鱼类最具代表性的二个物种—鲤和草鱼IL17受体基因家族的起源进化,实验采用比较基因组学和生物信息学的方法,分别在鲤和草鱼基因组数据库进行序列比对和注释,然后对得到的基因进行结构域和系统发育学分析,最后在12个不同组织中进行基因表达分析研究。结果显示,在鲤和草鱼中分别注释得到9个和5个IL17受体基因家族成员。系统发育分析显示,该基因家族不存在鱼类特有的基因,在硬骨鱼类中具有一定的保守性。比较基因组学结果显示,与四足动物相比,大多数硬骨鱼类中IL17受体基因没有明显增多。鲤与草鱼等其他硬骨鱼类相比,除IL17RB以外,其余IL17受体基因家族成员均加倍。不同组织的表达分析结果显示全基因组复制后不同基因拷贝的功能发生了分化。研究表明,虽然硬骨鱼经历第三轮全基因组复制,但是由于复制发生时间久远,大多数基因已经发生改变或退化,进而在基因组中丢失。而鲤第四轮基因组复制时间发生在820万年前,复制发生时间较近,故复制后的基因基本得以保留。但是对于一些具有特殊功能的高度保守基因(例如IL17RB),也会发生在极短时间内出现丢失现象。鲤和草鱼健康组织的表达谱分析结果同样表明,鲤IL17受体基因的不同拷贝之间已经发生了快速进化及亚功能化,并且这种现象在鲤四倍体基因组中普遍存在。     

团头鲂Hox基因家族的鉴定、进化与表达分析

Hox基因家族在调控动物早期胚胎发育、组织和器官生长起重要作用,因此这类基因家族被广泛应用到物种进化和发育调控的研究中。为了探究Hox基因在团头鲂中分布,进化及表达调控作用,同时为了探究Hox基因与团头鲂肌间刺发育的关系,研究基于团头鲂全基因组数据,结合生物信息学分析方法对其Hox基因家族进行鉴定、染色体分布、系统进化和表达模式分析。结果显示,在团头鲂基因组中共鉴定出49个Hox基因,根据系统进化分析分为5个亚类;其中49个Hox基因不均匀的分布在5条染色体上,并分为7个基因连锁群（HoxAa、HoxAb、HoxBa、HoxBb、HoxCa、HoxCb和HoxDa）;表达模式分析结果表明,团头鲂Hox基因家族成员具有不同的表达模式;团头鲂和斑马鱼所有Hox基因在肌肉中的表达水平存在显著差异。此外,团头鲂不同发育阶段及不同组织转录组结果显示,HoxA基因群集中,HoxA2a、HoxA3a在幼鱼阶段高表达,其他基因在肌肉、肌间刺及结缔组织中表达量低甚至不表达;HoxB基因群集中,HoxB9a、HoxB3a、HoxB8a、HoxB1b、HoxB5a、HoxB5b在幼鱼阶段高表达;HoxB7a、HoxB10a、HoxB9a在成鱼肌肉、结缔组织及肌间刺中高表达;HoxC基因群集中,HoxC3a、HoxC4a在幼鱼阶段高表达,HoxC3a、HoxC8a在成鱼的3个组织都有表达;HoxD基因群集中,HoxD9a、HoxD10a和HoxD11a在胚胎S2期表达量较高。研究表明,Hox基因在团头鲂早期胚胎时期和肌间刺的形成中有表达,提示团头鲂肌间刺的形成可能受Hox基因家族调控。     

半滑舌鳎(Cynoglossus semilaevis)Sox基因家族生物信息学分析

Sox(SRY-related HMG-box)基因家族是在动物体内发现的一类编码转录因子的基因家族,广泛参与了动物生长发育、理化反应,特别是性别决定和分化等过程.本研究采用生物信息学方法,利用Sox基因高度保守的HMG-box区序列作为种子序列,检索半滑舌鳎(Cynoglossus semilaevis)基因组注释的蛋白数据库,共鉴定分离出23个Sox基因.并在全基因组水平对半滑舌鳎Sox基因家族进行了保守结构域序列、进化、基因结构、染色体定位及基因表达模式的系统分析.结果显示,通过保守结构域分析发现了半滑舌鳎Sox基因家族除CseSox32外,皆存在一段9个氨基酸残基(RPMNAFMVW)的高度保守基序;结合保守结构域及进化分析,所有半滑舌鳎Sox基因被分为B1、B2、C、D、E、F和K共7个亚族,且不同的亚族在进化上存在种间趋同性和种内特异性;基因结构分析将半滑舌鳎Sox基因分为两大类,即单外显子类和多外显子类;而染色体定位分析则显示,Sox基因在染色体上散乱分布,不存在集簇现象;不同类型性腺及幼鱼变态前后的Sox基因家族表达谱显示,半滑舌鳎Sox基因具有不同的组织表达模式,表明其在性别分化、性腺发育及早期幼鱼发育过程中可能发挥了重要作用.本研究对于今后半滑舌鳎Sox基因家族深入的功能验证及分子作用机制研究具有重要的意义,也为日益丰富的水产基因组资源的挖掘利用提供了参考.     

青海湖裸鲤FXYD基因家族鉴定、分子进化及表达

青海湖裸鲤是唯一一种适应青海湖高盐碱水环境的鲤科鱼类。苯丙氨酸-X-酪氨酸-天冬氨酸(FXYD)家族是一类小分子单跨膜蛋白，具有调节离子通道作用，在多种生物的盐度胁迫和盐度适应中发挥重要作用。笔者基于青海湖裸鲤全基因组数据，利用生物信息学方法，鉴定到16个青海湖裸鲤FXYD(gpFXYD)基因，通过多重序列比对和系统进化分析，16个gpFXYD基因成员分属于5个亚型。共线性分析表明，青海湖裸鲤FXYD基因家族中12个成员起源于全基因组复制，且与斑马鱼FXYD基因存在共线性，推测全基因组复制导致了青海湖裸鲤FXYD基因的加倍。分子进化分析显示，gpFXYD1b/1c和gpFXYD5c/5d基因的进化选择压力(Ka/Ks)>1,表明其在进化过程中受到了正选择，可能发生了适应性进化。不同亚家族在青海湖裸鲤多种组织表达中，gpFXYD1s基因在青海湖裸鲤的心脏和脑组织特异性表达，而gpFXYD7s基因在青海湖裸鲤的脑组织中特异表达，分析gpFXYD基因不同亚型可能在不同组织中发挥功能。组织表达中，gpFXYD5s、gpFXYD6s、gpFXYD11s基因在青海湖裸鲤肾脏和鳃组织中出现显著...     

半滑舌鳎(Cynoglossus semilaevis)Sox基因家族生物信息学分析

Sox(SRY-related HMG-box)基因家族是在动物体内发现的一类编码转录因子的基因家族,广泛参与了动物生长发育、理化反应,特别是性别决定和分化等过程。本研究采用生物信息学方法,利用Sox基因高度保守的HMG-box区序列作为种子序列,检索半滑舌鳎(Cynoglossus semilaevis)基因组注释的蛋白数据库,共鉴定分离出23个Sox基因。并在全基因组水平对半滑舌鳎Sox基因家族进行了保守结构域序列、进化、基因结构、染色体定位及基因表达模式的系统分析。结果显示,通过保守结构域分析发现了半滑舌鳎Sox基因家族除Cse Sox32外,皆存在一段9个氨基酸残基(RPMNAFMVW)的高度保守基序;结合保守结构域及进化分析,所有半滑舌鳎Sox基因被分为B1、B2、C、D、E、F和K共7个亚族,且不同的亚族在进化上存在种间趋同性和种内特异性;基因结构分析将半滑舌鳎Sox基因分为两大类,即单外显子类和多外显子类;而染色体定位分析则显示,Sox基因在染色体上散乱分布,不存在集簇现象;不同类型性腺及幼鱼变态前后的Sox基因家族表达谱显示,半滑舌鳎Sox基因具有不同的组织表达模式,表明其在性别分化、性腺发育及早期幼鱼发育过程中可能发挥了重要作用。本研究对于今后半滑舌鳎Sox基因家族深入的功能验证及分子作用机制研究具有重要的意义,也为日益丰富的水产基因组资源的挖掘利用提供了参考。     

鱼类IRF家族在干扰素抗病毒免疫反应中的调控功能

干扰素调节因子(IRF)家族成员是一类重要的转录因子,在机体细胞感染病毒时单独或共同调控干扰素基因(IFN)的表达。IRF家族蛋白结构非常保守。其中N端DBD结构域赋予了IRF蛋白结合IFN启动子的功能,而C端IAD主要介导蛋白互作,因而不同IRF成员可能在不同的信号通路中发挥功能。哺乳动物IRF家族有9个成员,IRF1～9。鱼类IRF家族有11个成员,除了IRF1～9外,还包括硬骨鱼类特有的IRF11,以及在鸟类基因组中也存在的IRF10。哺乳类研究表明,IRF1/3/5/7/9在病毒感染的细胞中正调控IFN基因的表达,而IRF2则负调控IFN的表达。近十多年来,鱼类IRF家族的功能研究取得了重要进展,相关研究结论基本来自于体外的实验数据。本文综述了鱼类IRF家族成员的表达、亚细胞定位以及调控IFN抗病毒免疫反应的分子机制。     

热应激对大菱鲆心肌损伤及细胞凋亡的影响

为解析热应激对大菱鲆心脏损伤及其机制,实验从组织形态、生理生化反应及凋亡基因表达等多个水平,分别使用H.E染色法、电镜观察法、酶活性检测法、qPCR检测基因表达法开展了本研究。结果显示,随着温度升高,心肌纤维肿胀,断裂,间质宽度增加,炎性细胞浸润,线粒体结构破坏等组织损伤现象加重,但在24°C-24 h时组织损伤明显减轻;CK活性随着热应激加剧显著升高;LDH、SOD活性,MDA含量在24°C时达到峰值,表明大菱鲆遭受到热应激,心肌防御酶发挥抵抗作用,维持机体稳态。qPCR显示,大菱鲆心肌细胞Bax基因和Caspase-3基因变化趋势一致,随着热应激的加剧,表达量降低,而Bcl-2基因逐渐升高。表明在热应激程度较轻时,大菱鲆心肌通过降低Bax、Caspase-3基因表达,促进抗凋亡基因Bcl-2的表达,减少心肌细胞丢失来减少热应激损伤。当热应激加剧至28°C时,热应激超过自身生理调节阈值,损伤加重,机体防御系统自身也受损,造成大菱鲆心脏结构严重损伤甚至机体死亡。研究表明,随着温度升高,大菱鲆心肌损伤加重,机体通过调节心肌防御酶活性以及使细胞凋亡,最大限度维持稳态,减少组织损伤。超过24...     

豹纹鳃棘鲈酪氨酸酶Tyr基因家族的结构特征及组织表达分析

酪氨酸酶蛋白家族(tyrosinase gene family)是一类调控黑色素合成的关键酶, 在黑色素细胞形成的过程中起着不可替代的作用, 然而 Tyr 基因家族在东星斑体色形成中的潜在机制尚不清楚。豹纹鳃棘鲈(Plectropomus leopardus)俗称东星斑, 是我国重要的热带经济养殖鱼类, 但是人工养殖的东星斑因环境等变化而逐渐出现体色变淡或者变黑的现象, 严重影响其品质和经济价值。本研究从东星斑全基因组中共筛选鉴定获得 5 个 Tyr 基因家族成员, 氨基酸序列比对结果显示不同物种间的同源基因保守性较高, 尤其是 Tyr 家族典型的酪氨酸酶功能域在不同物种各成员之间均具有高度保守性。系统发育和共线分析均显示东星斑 Tyr 基因家族进化过程中存在基因复制和丢失现象。此外, 荧光定量 PCR 结果表明 Tyr 基因家族所有成员在东星斑黑色个体的皮肤组织中表达量均显著高于红色个体(P＜0.05)。本研究初步鉴定和分析了东星斑 Tyr 基因家族在其体色形成中的作用, 旨为深入解析东星斑酪氨酸蛋白酶基因家族的进化及功能机制提供依据。     

缢蛏ABC转运蛋白基因家族成员全基因组鉴定及表达模式分析

腺苷三磷酸结合盒转运蛋白(ATP binding cassette transporter,ABC transporter)家族是最古老的膜蛋白家族之一，广泛存在于原核生物和真核生物体内，利用ATP水解释放的能量对氨基酸、脂质、抗生素等物质进行跨膜运输，参与生物体内多种生理活动。目前，对软体动物ABC转运蛋白家族的鉴定，仅在虾夷扇贝(Patinopecten yessoensis)、栉孔扇贝(Chlamys farreri)和长牡蛎(Crassostrea gigas) 3种双壳类中有系统研究，对缢蛏(Sinonovacula constricta) ABC转运蛋白家族的鉴定和表达模式分析尚未见报道。利用缢蛏基因组和转录组数据，运用本地及NCBI在线BLAST程序、FGENESH+、SMART、Ex PASy、MEGA X、Mev 4.90和MapInspect等生物信息学分析工具，在全基因组水平系统地鉴定出52个缢蛏ABC转运蛋白，并对转运蛋白基因外显子数目、染色体定位等信息进行分析；通过系统进化分析，将缢蛏ABC转运蛋白家族分为8个亚家族，即ABCA～ABCH；通过比较分析不同物种...     

Responses of scallop biodeposits to bioturbation by a deposit‐feeder Apostichopus japonicus (Echinodermata: Holothuroidea): does the holothurian density matter?

The deposit‐feeding holothurians can reduce the negative impact of bivalve farming by feeding and reworking bivalve wastes (biodeposits) in the context of co‐culture. To test effects of the bioturbation by holothurians of different densities on bivalve wastes, a stocking density regime of the sea cucumber Apostichopus japonicus (35.4 ± 1.2 g, mean ± SE) was set at 0.0, 6.6, 13.2 ind m^?2, and responses of the biotic parameters including chlorophyll a concentration (Chl. a), bacterial biomass and the abiotic ones as oxidation‐reduction potential (ORP), organic matter (OM), organic carbon (OC), total nitrogen (TN) and organic phosphorus (OP) in biodeposits discharged by Japanese scallop Patinopecten yessoensis were investigated. Results showed that A. japonicus grew in a density‐dependent manner, and the density‐dependent effect on both biotic and abiotic parameters in biodeposits were also observed. Apostichopus japonicus stimulated a transfer process from reduction to weak reduction state of the biodeposits with a trend of higher density holothurians stimulating the process more. Furthermore, A. japonicus significantly controlled the bacterial abundance and Chl. a, as well as reducing the contents of OM, OC, TN and OP in the biodeposits. Yet, the response of abiotic parameters delayed rather than that of biotic parameters, underling the biotic parameters could be more sensitive to bioturbation than the abiotic ones. Our study suggests that the bioturbation of A. japonicus plays an important role in retarding organic waste accumulation and cleansing nutrients in bivalve farming wastes under co‐culture condition and the bioremediation capacity may be closely dependent on its stocking density in practice.     

中国明对虾MKK3 基因cDNA 克隆及其在氨氮胁迫下的表达

采用RACE技术克隆获得中国明对虾(Fenneropenaeus chinensis)丝裂原活化蛋白激酶激酶3(MKK3)基因全长c DNA序列,并对该序列进行分析。结果表明,该基因全长为1434 bp,开放阅读框长1011 bp,5′非编码区长33 bp,3′非编码区长390 bp,将该基因命名为Fc MKK3。推测该基因编码336个氨基酸,分子量为37.89 k D,理论等电点为6.08。同源性和系统进化分析表明,Fc MKK3基因与丽蝇蛹集金小蜂(Nasonia vitripennis)和地中海实蝇(Ceratitis capitata)的相似性分别为69%和68%,与其他节肢动物MKK3聚为一类。荧光定量RT-PCR结果表明,Fc MKK3基因在肌肉中的相对表达量最高,其次为鳃。氨氮胁迫后该基因在中国明对虾肠、鳃、胃、心脏、肝胰腺、肌肉和血细胞中的表达量均显著增加,并有不同的时空表达趋势,表明Fc MKK3基因可能在中国明对虾应对非生物胁迫反应的过程中起着重要的作用。     

Identification and characterization of pathogens associated with fin erubescence and ulceration of cultured Scophthalmus maximus

Scophthalmas maximus is a precious and main aquacultural species in northern China with an annual output value of more than 1.5 billion yuan. However, with the expansion of breeding range, increased stocking density and variety degradation, a variety of bacterial, parasitic and viral diseases have often occurred and worsened. Among them, bacterial disease is the most serious in farmed S. maximus. Since 2010, an epidemic bacterial disease with primary symptoms of lighter colour of lateral and caudal fins, spotty bleeding, fin base bleeding, abdominal swelling and redness and lesions of internal organs has put broken in S. maximus cultured in Weihai, Longkou and Haiyang, Shandong Province, China. The disease occurred mostly at the seedling and early development stages and propagated very fast, resulting in high mortality. These S. maximus died with obvious surface ulceration in only 3–4 days, causing great economic losses to the aquaculture industry. Beginning in 2010, we conducted epidemiological investigation in farmed S. maximus and isolated two different pathogens from the body of the diseased S. maximus from different farms. In this paper, we observed their morphology, conducted phylogenetic analysis based on their physiological and conventional biochemical characteristics and 16S rRNA gene sequences, preliminarily analysed their pathogenesis and investigated the histopathological changes of the diseased S. maximus. We believed that Vibrio anguillarum and V. parahaemolyticus were the pathogenic bacteria for the epidemic disease in S. maximus.     

Experimental collection of great scallop postlarvae and other benthic species in the Bay of Brest: settlement patterns in relation to spatio-temporal variability of environmental factors

Settlement patterns of great scallop (Pecten maximus) postlarvae and other benthic species in the Bay of Brest were studied from 2-D and 3-D collectors to clarify biotic interactions at the postlarval stage. Plane tiles became colonized mainly by epifaunal suspension feeders, while the 3-D substrata collected a more diverse fauna. Both species diversity and total abundance were higher in Netlon bags, compared with sandstone tiles. However, hydroids, bryozoans, tubicolous polychaetes, a number of epifaunal molluscs and macroalgae were more abundant on tiles. Between-sites differences in taxonomic group abundances mostly reflected the benthic fauna and flora beneath the collectors and would be explained by differential settlement and survival, according to local environmental conditions. Sediment type, depth, salinity, water turbulence, food and biotic interactions would be the factors regulating settlement. Bryozoans, hydrozoans, Anomia ephippium, Crepidula fornicata, mussels, tubicolous polychaetes, Pisidia longicornis, Hiatella arctica, Aequipecten opercularis and Chlamys varia were the main potential competitors of Pecten maximus collected. Crabs and Nassaridae would account for most of the potential scallop predators. Possible ways of improving scallop spat collection and cultivation are discussed with reference to the efficiency and placement of collectors, to environmental characteristics and to the intensity of biotic interactions at the postlarval stage.     

饲料中添加大豆皂甙对大菱鲆幼鱼生长和肠道健康的影响

为研究大豆皂甙对大菱鲆幼鱼生长性能、消化酶活性、肠道组织结构完整性和肠道菌群结构的影响,在以鱼粉为蛋白源的基础饲料中分别添加0%和0.3%的大豆皂甙,配制成鱼粉组和大豆皂甙组2种等氮等脂的实验饲料来投喂体质量为(4.63±0.01) g的大菱鲆进行12周的摄食生长实验。结果显示,饲料中添加0.3%的大豆皂甙对大菱鲆的生长性能没有产生显著影响,但显著降低了胃蛋白酶及肠淀粉酶活性;2组实验中大菱鲆肠道组织形态无明显差异,但大豆皂甙组肠道紧密连接蛋白的基因表达量显著降低。肠道菌群分析结果显示,大菱鲆肠道中相对丰度最高的门和属分别为变形菌门和盐单胞菌属。LEfSe和MetaStat分析显示,饲料中添加大豆皂甙后显著提高了大菱鲆肠道内优势菌(变形菌门及希瓦氏菌属),皂甙水解相关的肠道微生物(鞘脂单胞菌属、普氏菌属、栖瘤胃普雷沃菌以及普通拟杆菌)及潜在致病菌(莫氏杆菌属和发光杆菌属)的相对丰度,同时显著降低了Caenimonas、Niastella和条件致病菌罗尔斯通菌属的相对丰度。研究表明,0.3%大豆皂甙抑制了大菱鲆消化酶活性及肠道紧密连接蛋白的基因表达,且引起了大菱鲆肠道菌群结构的显著改变。因此,大豆皂甙对鱼类肠道健康尤其是肠道菌群的影响不容忽视,值得进一步研究。     

Environmental factors regulating the recruitment of walleye Sander vitreus and white bass Morone chrysops in irrigation reservoirs

Understanding the environmental factors that regulate fish recruitment is essential for effective management of fisheries. Generally, first‐year survival, and therefore recruitment, is inherently less consistent in systems with high intra‐ and interannual variability. Irrigation reservoirs display sporadic patterns of annual drawdown, which can pose a substantial challenge to recruitment of fishes. We developed species‐specific models using an 18‐year data set compiled from state and federal agencies to investigate variables that regulate the recruitment of walleye Sander vitreus and white bass Morone chrysops in irrigation reservoirs in south‐west Nebraska, USA. The candidate model set for walleye included only abiotic variables (water‐level elevation, minimum daily air temperature during winter prior to hatching, annual precipitation, spring warming rate and May reservoir discharge), and the candidate model set for white bass included primarily biotic variables (catch per unit effort (CPUE) of black crappie Pomoxis nigromaculatus, CPUE of age‐0 walleye, CPUE of bluegill Lepomis macrochirus and CPUE of age‐3 and older white bass), each of which had a greater relative importance than the single abiotic variable (minimum daily air temperature during winter after hatching). Our findings improve the understanding of the recruitment of fishes in irrigation reservoirs and the relative roles of abiotic and biotic factors.     

Molecular characterization and expression analysis of AMPK α subunit isoform genes from <Emphasis Type="Italic">Scophthalmus maximus</Emphasis> responding to salinity stress

AMP-activated protein kinase (AMPK) is a highly conserved and multi-functional protein kinase that plays important roles in both intracellular energy balance and cellular stress response. In the present study, molecular characterization, tissue distribution and gene expression levels of the AMPK α1 and α2 genes from turbot (Scophthalmus maximus) under salinity stress are described. The complete coding regions of the AMPK α1 and α2 genes were isolated from turbot through degenerate primers in combination with RACE using muscle cDNA. The complete coding regions of AMPK α1 (1722 bp) and α2 (1674 bp) encoded 573 and 557 amino acids peptides, respectively. Multiple alignments, structural analysis and phylogenetic tree construction indicated that S. maximus AMPK α1 and α2 shared a high amino acid identity with other species, especially fish. AMPK α1 and α2 genes could be detected in all tested tissues, indicating that they are constitutively expressed. Salinity challenges significantly altered the gene expression levels of AMPK α1 and α2 mRNA in a salinity- and time-dependent manners in S. maximus gill tissues, suggesting that AMPK α1 and α2 played important roles in mediating the salinity stress in S. maximus. The expression levels of AMPK α1 and α2 mRNA were a positive correlation with gill Na⁺, K⁺-ATPase activities. These findings will aid our understanding of the molecular mechanism of juvenile turbot in response to environmental salinity changes.     

牙鲆和半滑舌鳎5S rDNA基因的染色体定位及鲽形目5种鱼类的分子系统学分析

利用荧光原位杂交(FISH)技术将5S rDNA基因定位在牙鲆和半滑舌鳎染色体上,结果表明,5S rDNA基因在雌、雄性半滑舌鳎的一对同源染色体上分别存在2个杂交信号位点;在二、三倍体牙鲆的同源染色体上分别存在2个和3个杂交信号位点,杂交信号明显且特异。本研究首次将5S rDNA基因定位在半滑舌鳎和三倍体牙鲆的染色体上,为牙鲆及半滑舌鳎倍性鉴定、染色体鉴别提供了有效方法。此外,根据牙鲆5S rDNA基因编码区序列设计引物,扩增出大菱鲆和半滑舌鳎5S rDNA基因编码区序列,与鲽、塞内加尔鳎、大口黑鲈、七鳃鳗的5SrDNA基因序列进行同源性比较后发现,5种鲽形目鱼类5S rDNA基因序列同源性高达98.3%,系统发生分析结果显示5种鲽形目鱼类聚为一支;各序列中GC含量均显著高于AT含量。     

Relationships among invasive common carp,native fishes and physicochemical characteristics in upper Midwest (USA) lakes

Abstract – Common carp Cyprinus carpio is a widespread invasive species that, in high abundance, can impose numerous deleterious effects in aquatic ecosystems. Common carp increase turbidity and nutrient availability while reducing invertebrate prey resources and aquatic macrophytes, transforming shallow lakes from the clear‐ to turbid‐water state. However, potential effects of common carp on native fish communities have received limited attention. We evaluated the relationships among relative abundances of nine native fishes and common carp for 81 lakes in eastern South Dakota and their associated physicochemical characteristics. Inverse threshold relationships among relative abundances of native fishes and common carp were identified for black bullhead Ameiurus melas, black crappie Pomoxis nigromaculatus, bluegill Lepomis macrochirus, white bass Morone chrysops and northern pike Esox lucius, while marginally significant relationships were detected for largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu. Lakes where common carp relative abundance exceeded 0.6 fish per net night had low abundance of native fishes, whereas lower abundance of common carp resulted in variable abundance of native fishes. Lakes with abundance of common carp surpassing 0.6 fish per net night were also characterised by larger surface areas and watersheds and impaired water quality (higher dissolved solids and chlorophyll a concentrations and lower secchi depth). Our results are consistent with the biotic‐abiotic constraining hypothesis that proposes biotic factors can regulate fish populations regardless of abiotic conditions. Thus, common carp abundance may need to be reduced and sustained below ecological thresholds to improve water quality and increase abundance of native fishes.     

中国明对虾MKK4基因克隆及其在氨氮胁迫下的表达分析

为初步研究中国明对虾MKK4的生物学功能,采用RACE技术克隆获得中国明对虾MKK4基因全长cDNA序列,并对该序列进行分析。结果显示,中国明对虾MKK4基因全长为2 064 bp,开放阅读框长1 221 bp,5'非编码区长214 bp,3'非翻译区长629 bp。将该基因命名为FcMKK4。推测该基因编码406个氨基酸,预测分子量为45.94 ku,理论等电点为8.50。同源性和系统进化分析发现FcMKK4与肩突硬蜱和印度跳蚁的同源性分别为80%和78%,与其他节肢动物MKK4聚为一支。荧光定量RT-PCR结果表明,FcMKK4基因在肌肉中的相对表达量最高,其次为肝胰腺。氨氮胁迫后该基因在中国明对虾肌肉、肝胰腺、血细胞、鳃、心脏、肠和胃中的表达量均显著增加,并有不同的时空表达谱式,表明FcMKK4可能参与中国明对虾非生物胁迫的应答反应。