大型溞(Daphnia magna)线粒体基因组的测定与序列分析

利用Long-PCR及普通PCR技术,结合引物步移法测序,经拼接、组装后获得中国淮河大型溞(Daphnia magna)线粒体基因组全序列,并对其基因组成、结构特点等进行初步分析.大型溞线粒体基因组全长为14948 bp,A、T、G、C各碱基含量分别为32.37%、34.73%、15.58%、17.31%,表现出明显的AT偏倚.13个蛋白质编码基因、22个t RNA基因、2个rRNA基因和1个D-loop区(控制区)的排列方式与典型的节肢动物线粒体基因组的排列方式略有不同.除COI基因以CTG、ATP8基因以GTG、ND3基因以ATC以及ND6基因以ATT为起始密码子以外,其余9个蛋白质编码基因均以ATG作为起始密码子;9个蛋白质编码基因具有典型的完全终止子TAG或TAA,COI、COII、ND4和ND5等基因采用不完全终止密码子T.基因组包含9个基因间隔区,共81 bp,长度1~62 bp;13个基因重叠区,共77 bp,重叠碱基数在1~27 bp之间,最大重叠在16 S rRNA和tRNA~(Val)基因之间.在预测的22个tRNA基因的二级结构中,发现只有tRNA~(Ser1)基因未能形成完整的二级结构,其他21个基因均可形成典型的三叶草结构.16 S rRNA和12 S rRNA基因长度分别为1373 bp和752 bp,D-loop区全长289 bp.本研究结果为探讨大型溞在溞属中的系统学地位及其与其他种间的系统发生关系等问题提供了数据资源.     

Cloning and developmental expression of kinesin superfamily7 (kif7) in the brackish medaka (Oryzias melastigma), a close relative of the Japanese medaka (Oryzias latipes)

kif7 is a member of the kinesin superfamily members which are molecular motor proteins that move along microtubules in a highly regulated manner through ATP hydrolysis. In this paper, we report on the cloning of the Oryzias melastigma kif7 (omkif7) using primers designed according to the Japanese medaka (Oryzias latipes) database. The cloned omkif7 has an open reading frame of 3762bp and is deduced to encode a polypeptide of 1254 amino acids that possesses the putative ATP-binding and microtubule-binding motifs in its motor domain at the N-terminal region. We characterized the cloned omkif7 by comparison with the zebrafish kif7. Both omkif7 and zebrafish kif7 are shown to be expressed in all embryonic stages and adult tissues examined with higher expression level in the testis and ovary. Whole-mount in situ hybridization revealed that the expression of omkif7 is ubiquitous during the early stages of embryonic development, but became more restrictive and localized to the brain, fin bud and eye at later development. This study suggested that the brackish O.melastigma can serve as a good seawater model organism for developmental studies by utilizing the resources developed from its close relative of the Japanese medaka.     

微囊藻(FACHB-905)和鱼腥藻(FACHB-82)响应温度变化的功能特性权衡

微囊藻和鱼腥藻是水华蓝藻的两个主要类群,两种藻均可调节自身形态及生理特性来维持快速生长,这也是两个类群蓝藻水华维持的基础.本研究分析了微囊藻(FACHB-905)和鱼腥藻(FACHB-82)生长、形态及叶绿素荧光参数对温度变化的响应,以及生长与特性间的权衡关系.结果显示:该微囊藻细胞直径随温度升高而降低,但是比增长速率维持稳定,表明在高温条件下,其可能通过减小细胞大小的方式维持比增长速率;该鱼腥藻在不同温度下,平均细胞直径和藻丝长度呈现显著变化,高温条件下,其维持较高的比增长速率,但是细胞直径增大,藻丝长度缩短,这可能是其调节自身形态以维持较高比增长速率的方式.该微囊藻和鱼腥藻分别在细胞较大和较小时,藻细胞潜在的光化学效率更高.本研究表明这两种蓝藻可以通过权衡藻细胞形态、生理特性两者与生长速率之间的关系来适应温度的变化以达到自身最佳的生长状态,微囊藻(FACHB-905)通过调节细胞大小和光合活性来维持生长优势,而鱼腥藻(FACHB-82)则通过细胞大小、藻丝长度和光合活性的调节来维持生长优势.本研究的结果有助于提升对于水华蓝藻生长维持机制的认识.     

Reproductive traits of the freshwater shrimp Caridina fossarum Heller, 1862 (Decapoda, Caridea, Atyidae) in the Ghomp-Atashkedeh spring (Iran)

In the present study, some biological traits of Caridina fossarum reproduction are studied in the Ghomp-Atashkedeh spring (Fasa, Shiraz, Iran), for the first time. This Iranian endemic freshwater species was studied from April 2007 to March 2008. Minimum sexable size (MSS) and absolute or relative size at the onset of maturity (SOM and RSOM) in terms of carapace length (CL) was found to be 2.4 mm, 4.3 mm and 55%, respectively. Sex ratio showed variations on a monthly basis. Sex reversal is a possible scenario for C. fossarum because the size-specific sex ratio revealed a reverse pattern. Based on the proportions of ovigerous females, the main breeding season was determined to be from April to August, demonstrating a peak during early spring. There is a period of extended recruitment at water temperatures above 20 °C. The size at which 50% of females are mature was estimated at CL = 5.03 mm from the proportion of ovigerous females during the breeding season. The pleopodal egg number varied from 3 to 75 eggs per female with a mean value 34.39 ± 14.27. The results showed that although there is a significant relationship between carapace length CL and pleopodal egg number, it is not the most important factor affecting potential fecundity in C. fossarum due to the low values of slope (= 1.51) and determination coefficient (= 0.052).     

Comparative petroleum hydrocarbons levels and biochemical responses in mussels from hydrothermal vents (Bathymodiolus azoricus) and coastal environments (Mytilus galloprovincialis)

Aliphatic hydrocarbons and PAHs in the whole soft tissues of Bathymodiolus azoricus from three Mid-Atlantic Ridge hydrothermal vents (Menez-Gwen, Lucky Strike and Rainbow), and Mytilus galloprovincialis from three contaminated coastal sites in South Portugal were analysed, and its effects on the digestive gland microsomes mixed-function oxygenase system (MFO) were assessed.Aliphatic hydrocarbons levels were present in the same magnitude in both coastal and hydrothermal environments, while the UCM (unresolved complex mixture) for coastal mussels were higher than in vent mussels. In general, significantly higher PAHs concentrations were found in coastal mussels, compared to B. azoricus where low molecular weight PAHs (2–3 rings) represented the majority of PAHs contrarily to what was observed in M. galloprovincialis. The MFO components were present in both mussel species, and were detected in vent mussels for the first time. However this system seems to have different roles in species from these contrasting environments. In coastal mussels MFO responded to hydrocarbon contamination while response in hydrothermal organisms appeared to be related mainly to endogenous factors.     

The Contribution of Ecdysis to the Fate of Copper, Zinc and Cadmium in Grass Shrimp, Palaemonetes pugio Holthius

Depuration through ecdysis by grass shrimp, Palaemonetes pugio, was examined by exposure to a sublethal mixture of copper, zinc and cadmium for 72 h, followed by placement in uncontaminated water to molt. Percent eliminated with the exuviae varied for each metal; of the total intermolt body burden, 11% Cu, 18% Zn and 26% Cd was associated with the exuviae. Cu concentrations of intermolt exoskeletons were significantly higher than of the exuviae of post-ecdysis shrimp suggesting that Cu contained in the exoskeleton was reabsorbed before molting. Exuvial Cd concentration was not significantly different than the concentration of the intermolt exoskeleton, suggesting that most Cd in the exoskeleton was depurated with the exuviae. Although Zn whole-body burdens were lower after a molt, Zn losses were most likely due to excretion because exuvial concentrations were significantly lower than in the intermolt exoskeleton. Cu, Cd and Zn concentrations in exuviae shed in metal-enriched water were significantly higher due to adsorption than exuviae produced in uncontaminated water.     

五个湖泊中华刺鳅(Mastacembelus sinensis)种群线粒体细胞色素b遗传多样性分析

采用特异性引物对中华刺鳅基因组DNA进行扩增和测序,获得了江苏省5个湖泊的中华刺鳅种群线粒体cyt b基因767 bp的序列.分析表明,cyt b基因中A+T含量略高于G+C含量,144个中华刺鳅共获得cyt b基因单倍型28个,变异位点38个,其中单倍型Hap1分布最为广泛,可能为祖先型单倍型.平均单倍型多样性和平均核苷酸多样性指数分别为0.58751和0.00214,遗传多样性较低.群体间遗传分化系数为0.0356,绝大多数的遗传变异都来自群体内部,而群体间的遗传分化极小.构建的系统进化树未出现明显的以单个湖泊群体的聚簇,5个湖泊的种群间基因交流极其强烈.研究结果表明,当前5个湖泊的中华刺鳅遗传多样性水平比较低,亟待加强保护.     

Fungal infection of Eudiaptomus gracilis (Copepoda, crustacea) in Lake Mondsee

An Aphanomyces sp. (Oomycetes) was found to be an important egg parasite of Eudiaptomus gracilis (Copepoda) in Lake Mondsee (Austria). The infection is evidenced by densely packed infection hyphae, attached with holdfasts and wrapped around the female's abdomen. The infection hyphae give rise to hyphae which penetrate the egg sac, and subsequently kill all eggs. The infection obviously has no pathogenetic effects on the egg-carrying female. Infected females appear during summer and fall, mainly in warm water layers. Infected egg clutches are found at all seasons of the year, indicating considerable birth control of the Eudiaptomus population by parasite infection. It seems possible that the actual Aphanomyces sp. is not the only parasite involved.     

Effects of 4-nonylphenol exposure in mussels (Mytilus galloprovincialis) and crabs (Carcinus aestuarii) with particular emphasis on vitellogenin induction

Since it is often difficult to estimate possible adverse effects due to contamination in selected ecosystems, multi-species biomonitoring may provide more information, taking into account different routes of exposure, ecological roles and metabolic capabilities of animals. In this context, we exposed for 7 days the mussel Mytilus galloprovincialis and the crab Carcinus aestuarii to 4-nonylphenol (NP), a well-known xenoestrogen. In mussels (0–0.2 mg NP l⁻¹), we measured NP bioaccumulation in soft tissues and vitellogenin (Vg)-like protein levels in digestive glands from both males and females by the alkali-labile phosphate assay (ALP). As no reference data were available for crab exposure, the NP 96-h LC₅₀ value was previously determined. Then, in sublethally exposed (0–1.0 mg NP l⁻¹) male crabs, NP bioaccumulation and Vg levels were measured in hemolymph, gonads and digestive gland. Bioaccumulation of NP increased from 43 to 371 μg g⁻¹ d.w. in mussels, and from 3.6 to 37 μg g⁻¹ d.w. in crabs, depending on the NP concentration in water. Dose-dependent Vg-like protein induction was observed in both species, appearing to be related to NP bioaccumulation, although a partial decrease was recorded at the highest concentration tested. A similar trend was observed in both digestive gland and gonad of exposed crabs; Vg increased to a lesser extent, although significantly, in hemolymph. Results demonstrated that NP induces Vg synthesis both in male and female mussels, as well as in male crabs. On the basis of the responsiveness of both species investigated, a multi-species approach is indicated in biomonitoring programmes.     

Regional variations in trace element concentrations in tissues of black tiger shrimp Penaeus monodon (Decapoda: Penaeidae) from South Vietnam

The goal of the present study was to examine the specific bioaccumulation of 22 trace elements in muscle, exoskeleton and hepatopancreas of black tiger shrimp Penaeus monodon from the Mekong River Delta (MRD), and the South Key Economic Zone (SKEZ), South Vietnam. The general tendency in most trace element concentrations among different tissues were hepatopancreas > exoskeleton > muscle. Comparisons of trace element levels in tissues between the two regions showed that concentrations of Se in muscle and As in all three tissues were higher in SKEZ; whereas in MRD, the higher concentrations of most elements such as Mn, Cu, Cd, Ba, Hg, were observed in tissues. These geographical variations in trace element levels may reflect the differences in human activities between the two regions of South Vietnam. The target hazard quotient (THQ) values for trace elements (<1) indicate that local residents are not exposed to potential health risks via the consumption of shrimp.     

5个湖泊河川沙塘鳢(Odontobutis potamophila)种群线粒体细胞色素b基因的遗传变异分析

通过对5个湖泊的河川沙塘鳢种群的线粒体DNA细胞色素b基因进行PCR扩增、测序,获得1141 bp的序列全长.序列分析显示,cyt b基因序列中A+T含量(55.8%)略高于G+C含量(44.2%),共检测到806个多态位点,115个样本得到87个单倍型,平均单倍型多样性为0.969±0.012,核苷酸多样性为0.20081±0.00742,遗传多样性表现高度多样性.太湖种群与大纵湖种群间的遗传距离最近,为0.137,巢湖种群和大纵湖种群之间遗传距离最远,为0.424.分子方差分析表明,群体间遗传分化系数Fst为0.531,变异来自群体内及群体间.cyt b基因序列构建的UPGMA系统进化树显示,5个种群分化成不同的分支系谱,种群间存在的基因交流较少.     

Alien cyanobacteria Anabaena bergii var. limnetica Couté et Preisig from Lithuania: Some aspects of taxonomy, ecology and distribution

The anthropogenic eutrophication of surface waters and the global climate warming promoted some bloom-forming tropical cyanobacteria, including Anabaena, distribution northwards. Anabaena bergii var. limnetica was for the first time recorded in Lithuania from the hypertrophic Lake Gineitišk?s in 2008. It developed when the water temperature reached its annual maximum (July–August); its highest biomass (0.26 mg L⁻¹) was reached at the end of July. Akinetes formation started in the middle of August. The morphological variability of A. bergii var. limnetica morphospecies is presented. The morphological, ecological differences and distribution of A. bergii var. limnetica and the related morphospecies A. bergii, A. bergii f. minor, Anabaena minderi are discussed.     

长江中下游5个湖泊黄颡鱼(Pelteobagrus fulvidraco)种群线粒体细胞色素b基因的遗传变异分析

对长江中下游5个湖泊的黄颡鱼种群的线粒体DNA细胞色素b基因进行了PCR扩增、测序,获得了955 bp的序列.分析显示,cyt b序列中A+T含量略高于G+C含量,共检测到54个变异位点,60个样本得到37个单倍型,平均单倍型多样性为0.945±0.018,核苷酸多样性为0.00419±0.00043,遗传多样性表现中等.太湖种群与滆湖种群间的遗传距离最远为0.00651,鄱阳湖种群和巢湖种群之间遗传距离最近为0.00375.分子方差分析(AMOVA)表明,群体间遗传分化系数F_st为0.0684,几乎所有变异都来自群体内,群体间遗传分化极小.cyt b序列构建UPGMA系统进化树显示,5个种群没有分化成不同的分枝谱系,种群间存在广泛的基因交流.     

铁对拟柱孢藻(Cylindrospermopsis raciborskii)和角星鼓藻(Staurastrum spp.)季节动态和生长的影响——以广东大沙河水库为例

拟柱孢藻（Cylindrospermopsis raciborskii）和角星鼓藻（Staurastrum spp.）是热带亚热带浮游植物群落中的常见优势种类,为了解铁对2种浮游植物季节动态和生长的影响,本文通过对典型热带水库的野外调查,分析铁与2种藻生物量和相对生物量的季节动态的关系,并通过室内实验分别以无机磷（KH₂PO₄）和有机磷（C₆H₁₃O₉P）为磷源,比较3种铁浓度（0.029、0.29和0.689 mg/L）下拟柱孢藻（C.raciborskii,N8）和角星鼓藻（Staurastrum sp.,FACHB-1449）的比生长速率、铁载体产量和碱性磷酸酶活性的差异.结果显示,拟柱孢藻和角星鼓藻是浮游植物群落的主要优势种类,两者的生物量最大占到总生物量的82%以上;两者对环境变量响应的区别主要体现在对溶解性铁浓度变化的响应差异上,拟柱孢藻生物量与溶解性铁有显著的线性回归关系,但角星鼓藻的生物量与铁没有显著线性回归关系.室内实验中,拟柱孢藻N8的比生长速率在无机磷源铁浓度为0.689 mg/L条件下最大,为0.098±0.01 d^-1,2种磷源条件下比生长速率均随铁浓度降低而显著降低,6个实验组均检到铁载体：6个实验组角星鼓藻FACHB-1449的比生长速率没有明显差异,平均为0.079±0.001 d^-1,均未检出铁载体,磷源和铁浓度对其比生长速率的影响不显著;有机磷源条件下,拟柱孢藻N8实验组碱性磷酸酶活性均显著高于角星鼓藻FACHB-1449实验组,拟柱孢藻N8实验组酶活性随铁浓度降低而显著降低,但角星鼓藻FACHB-1449各实验组的碱性磷酸酶活性无明显差异.以上结果表明,水体中溶解性铁的供应对拟柱孢藻的种群动态和优势有重要作用,与角星鼓藻相比,拟柱孢藻的生长更易受到铁的限制,尤其在无机磷缺乏、磷源主要以有机磷形式供应时,铁对拟柱孢藻生长的限制作用增强.     

Life history and temporal distribution of Orchestia sp. cf. cavimana (Amphipoda, Talitridae) on a lake shore in central Italy

The life history of the amphipod Orchestia sp. cf. cavimana (Heller, 1865) was studied throughout the course of a year with monthly samplings and the use of pitfall traps along the shores of Lake Albano in central Italy. The data thus obtained showed two peaks in abundance (the first in June and the second in October) and a minimum capture frequency in February. Egg-bearing females were recorded in spring and late summer, whilst recruitment occurred from spring to autumn, with maximum in June and October. The data collected also indicated the presence of a positive correlation between the abundance of talitrids and both temperature and sediment moisture. Morphological analysis enabled the identification of four different cohorts (with a lifespan of the species of approximately 12–15 months) all four of which remained distinguishable throughout the course of the year. It, moreover, enabled sex determination in individuals of 5 or more millimetres. The subsequent distribution indicated that, when significant, the sex ratio was female biased and that maximum size was greater in males. In particular, maximum sizes were recorded in spring for both males and females and were of 17.5 and 13.0 mm, respectively. Furthermore, the total body length recorded for egg-bearing females was positively correlated with the number of eggs in their brood pouch.     

基于耳石微化学的长江靖江段长颌鲚与短颌鲚生境履历重建

为了解长江靖江段两种刀鲚生态型长颌鲚与短颌鲚的生境履历的不同,利用X射线电子探针微区分析技术研究采集自长江靖江江段的长颌鲚和短颌鲚个体耳石的锶和钙微化学特征.定量分析结果显示,短颌鲚个体的耳石锶、钙比值(即Sr/Ca×10~3)稳定在2.00左右,反映了其在纯淡水生活的习性;而长颌鲚的锶、钙比值波动显著,不仅具有对应淡水生活的低值(1.18±0.48~2.11±0.94),还具有对应半咸水生活的高值(3.39±0.60~6.79±1.13),反映了其溯河洄游的生活习性.短颌鲚因在淡水生活,其淡水系数(FC)值均为1.00,2013年和2014年长颌鲚的FC值分别为0.36±0.06和0.50±0.11,证明了长颌鲚与短颌鲚群体间存在差异,而且长颌鲚不同年份群体间也并不相同.长颌鲚和短颌鲚的洄游模式存在显著差异,同时不同年份间的长颌鲚也存在生境履历差异.靖江段长颌鲚资源群可能来自不同出生地起源及生活史背景不同的群体.该江段是两类刀鲚的重要栖息地或洄游通道.     

Cloning and expression of alpha class glutathione S-transferase gene from the small hermaphroditic fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae)

In order to assess its potential as a biomarker of aquatic pollution, an alpha class glutathione S-transferase gene (GSTα gene) was cloned from the small hermaphroditic fish Rivulus marmoratus. The R. marmoratus GSTα gene spanned 1.3 kb, consisting of 6 exons encoding 221 amino acid residues. It showed high similarity to zebrafish GST. We named this R. marmoratus GSTα gene as rm-GSTα. The cDNA of the rm-GSTα gene was also investigated for its phylogeny, tissue-specific and chemical-induced expression. Rm-GSTα was subcloned into a 6 × His-tagged pCR^®T7 TOPO TA expression vector to produce the recombinant 6 × His-tagged rm-GST protein. This will be used in future to raise an rm-GSTα antibody for use in the study of phase II metabolism involved in detoxification. We also exposed R. marmoratus to 300 μg/l of 4-nonylphenol in water, and found approximately 4-fold induction of R. marmoratus GSTα mRNA in the treated animals. In this paper, we discuss the characteristics of the R. marmoratus GSTα gene as well as its potential use in relation to environmental pollution.