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1.
Comparative study of morphometric measurements was undertaken on populations of Palaemonetes antennarius from two freshwater habitat zones (lacustrine pelagic and lacustrine littoral) and from the fluvial littoral habitat zone of three estuaries of north-western Greece. Multivariate statistical analyses (principal component analysis and discriminant function analysis) revealed clear morphometric differences between sexes and sampling sites. The observed differences are expressed mainly thought the measurements related to the body heights (carapace height and second pleon height), as a result of sexual dimorphism, High values for the female body heights seem to be correlated to specific fecundity profile and reproductive strategy. On the other hand, morphometrical variables related mainly to body lengths, such as rostral, telson and pleon lengths, were observed to be correlated to the study sites. Characters related to the summing capacity (telson length, telson width and pleon lengths) were generally found to have higher values in the specimens from habitats with high reophilic profile.  相似文献   

2.
付志鑫  李雪  刘妍  范亚文 《湖泊科学》2017,29(5):1274-1278
2011-2012年间对扎龙国家级自然保护区的藻类标本进行采集及观察鉴定.研究发现,该区域鼓藻类植物生物多样性较高,共观察到90个分类单位.研究过程中发现宽带鼓藻属的一个新种——Pleurotaenium parvulum Li,FanWei.该物种特征为植物体单细胞,细胞小型,长圆柱形;半细胞顶端平截,其缘边横断面可见5个小结节;细胞壁平滑或具点纹;半细胞具两个轴生星状的色素体,每个色素体具1个蛋白核.本文比较了该物种与其相近种类之间的差异.  相似文献   

3.
迄今为止,全球范围共报道出100多种鱼腥藻,中国记录报道的仅有50余种,但有些种类的描述仍较模糊.最近在福建、浙江等地进行野外调查时,发现了多种丝状蓝藻.其中就有2种鱼腥藻在中国尚未报道:威格鱼腥藻(Anabaenaviguieri Denis et Frémy 1923)和史密斯鱼腥藻(Anabaena smithii(Komárek)Watanabe 1992).  相似文献   

4.
5.
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.  相似文献   

6.
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.  相似文献   

7.
为了检验已记录的3种裸腹溞(发头裸腹溞(Moina irrasa)、短型裸腹溞(Moina brachiata)、微型裸腹溞(Moina micrura))的系统分类,用试剂盒法分别提取3种裸腹溞的基因组DNA.利用特异性引物,通过PCR扩增了3种裸腹溞的16S r DNA部分序列,并与来自Gen Bank中每个种类相似度较高的裸腹溞属序列进行分析.结果表明,3种裸腹溞的平均种间相似度为88.7%,碱基中A+T含量均明显高于G+C含量.本研究的发头裸腹溞的16S r DNA序列与Gen Bank所下载的多刺裸腹溞(Moina macrocopa)的16S r DNA序列相似度为99%,遗传距离(K2P双参考模型)为0.5%,属种内范围;两个地区的短型裸腹溞测得的16S r DNA序列与Gen Bank下载的欧洲短型裸腹溞的16S r DNA序列序列相似度相对较低(88%~90%),遗传距离较大(13.2%~13.5%左右),已达到属内种间分化水平.基于16S r DNA构建的NJ树和贝叶斯树也支持以上结论.结果表明,本研究的发头裸腹溞可能为多刺裸腹溞,本研究用的短型裸腹溞与Gen Bank下载的欧洲短型裸腹溞已经达到种间分化的标准.由于缺乏物种形态资料和其他分子标记的对比,3种裸腹溞的分类地位还需进行更深入的探讨.  相似文献   

8.
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.  相似文献   

9.
管乐  张民  赵兴青 《湖泊科学》2020,32(1):134-143
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.  相似文献   

10.
The variability of the respiratory surface area of Simulium monticola Friederichs, 1920 and Simulium argyreatum Meigen, 1838 pupae was studied in detail. 333 pupae from Western Carpathian Mts. were investigated. According to the tubercles on thorax and head of the pupa of S. monticola, two morphological forms were distinguished (S. monticola 1 and S. monticola 2). Both were studied separately. In any species or form respectively we measured the lengths of all respiratory filaments and basal trunks, the widths of the basal trunks, the widths of the filaments on their proximal and distal end and the widths 0.25 mm from the proximal end. In all species (forms) differences in the size of the respiratory surface area between the first (April – June) and the second generation (August – October) were found. In S. monticola 1 the mean real respiratory surface area was significantly (p < 0.001) larger in spring (3.67 mm2) than in summer (2.19 mm2). In S. monticola 2 the mean real respiratory surface area was 3.45 mm2 in spring, and it was significantly larger in females than in males (p = 0.034). In S. argyreatum the mean real respiratory surface area was 2.80 mm2 in spring 2001 while in different summer generations it was significantly smaller: 1.58 mm2 in 1999, 1.84 mm2 in 2000 and 2.12 mm2 in 2001. All these groups differed significantly from each other. Regression models could explain 64.5% (power model) of the real respiratory surface area in S. monticola 1 and 19.9% (various models) of the real respiratory surface area in S. argyreatum due to the variability of the adult size.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
16.
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.  相似文献   

17.
Sublimation was developed by Alley and Brown (2000) in order to isolate bacterial strains that were capable of degrading water insoluble compounds. In this study, sublimation was modified by the use of nutritional agar plates, instead of mineral salt agar, to isolate phenanthrene-degrading bacteria from a mixed culture that had been enriched under the selective pressure of high phenanthrene content. Five strains were obtained with different morphology and degradation ability. Based on the 16S rDNA sequence, two of them were classified as species of the genus Sphingomonas; the others as species of the genus Burkholderia. Denaturing gradient gel electrophoresis (DGGE) was introduced to detect dynamic changes in the bacterial community during enrichment batch culture, and to determine any correlation between the five isolates and the phenanthrene-degrading consortium. The DGGE profile indicated that these five isolates corresponded to four dominant bands of the consortium. Compared to traditional means of isolation, we concluded that modified sublimation is effective and more convenient.  相似文献   

18.
Rebi Nijboer   《Limnologica》2004,34(3):213-223
Agapetus fuscipes is a caddisfly that only seems to occur in unimpacted streams and therefore can be a suitable indicator species for natural conditions. The species has decreased in the Netherlands because of human activities which caused organic pollution and hydromorphological degradation. Literature was reviewed to study the autecology and life cycle of A. fuscipes in order to reveal the ecological requirements of this species. By taking Agapetus fuscipes as an example, it is shown that the autecology and life cycle of an indicator species can give important clues for its presence in unimpacted and absence in impacted streams. A. fuscipes is very susceptible to organic pollution and to a lesser degree to discharge dynamics (dropping water level and discharge peaks). The species copes with dynamic discharge events by maintaining a high population density and recolonisation of disturbed habitats from refuges. However, the vulnerability of the species strongly depends on the life stage of the animals (e.g., the ability to migrate, the oxygen demand and the habitat requirements differ between instars). Although several adaptations to dynamic conditions, a high frequency of discharge peaks or a long period of drought can cause the population to decline. Once a population has totally disappeared from a stream it will take the species a long time to recolonise the stream because of its low dispersion capacity. To protect this species stream restoration should focus on water quality (avoid organic pollution and agricultural run off) and on stabilising the discharge by taking care of natural infiltration in the catchment area instead of fast removal of rain water by drainage systems.  相似文献   

19.
Isolation and characterization of Aeromonas species were undertaken in the Ebrié lagoon (Abidjan, Côte d’Ivoire) over a one year period. Overall 63% of 501 water samples were identified as positive for Aeromonas spp. A. sobria, A. hydrophila and A. caviae represent respectively 49.20%, 20.63% and 30.15% of the positive samples. Thirty nine of the positive samples were recovered from surface water samples; while 24 bottom water samples were positive for Aeromonas. Aeromonas species are most frequently (82.53) present in the Ebrié lagoon urban area during the rainy and flood seasons when the salinity is low and below 10‰. A lower isolation frequency is noticed during the dry season when water salinity is over 10‰. Finally, a higher isolation frequency occurred in samples with highest counts of Escherichia coli.  相似文献   

20.
火烧作为调控因子,对植物群落结构和生态系统功能具有重要影响,但在湖泊湿地中研究较少.通过野外调查取样与实验室分析,探讨火烧对洞庭湖湿地主要群落类型——荻(Miscanthus sacchariflorus)和苔草(Carex brevicuspis)土壤化学性质的影响.结果表明:火烧后,苔草群落土壤硝态氮含量显著减少64.6%,有机质含量增加26.3%;而荻群落土壤与之相反,硝态氮含量增加186.9%,有机质含量减少22.9%.火烧后,苔草群落的全氮、铵态氮、全碳和全磷含量均显著增加,分别增加了75.4%、36.3%、102.7%和76.9%,而荻群落土壤与对照组间无显著差异.总体上,火烧对荻群落土壤养分影响不大,可作为芦苇场的一种管理方式,但火烧促进苔草群落土壤养分释放,有助于苔草群落提前萌芽和生长,并引起牲畜牧食增加.  相似文献   

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