巨藻中谷胱甘肽S转移酶基因对细长聚球藻PCC7942耐镉性的影响

谷胱甘肽S转移酶(glutathione S-transferase, GST)是一个较大的基因家族,在生物体生长发育和对环境变化响应中发挥重要的调控作用。本研究从巨藻(Macrocystis pyrifera)配子体中克隆了6个完整的GST基因(mpgst1、mpgst2、mpgst3、mpgst4、mpgst5和mpgst6)。随后将6个巨藻GST基因分别转化至细长聚球藻(SynechococcuselongatusPCC7942)中,提取细长聚球藻转化株基因组DNA作为模板进行PCR验证及测定转化株GST酶活进行基因功能验证,结果显示,6个mpgst基因都分别成功整合到细长聚球藻的基因组中,但只有含mpgst1、mpgst4和mpgst6基因的细长聚球藻转化株(MG1、MG4和MG6)具有耐镉性。在镉离子胁迫下,细长聚球藻转化株MG1、MG4和MG6的生长、光合色素含量和叶绿素荧光参数Fv/Fm值均显著高于野生株(P<0.05)。本研究结果为进一步研究巨藻GST基因的抗重金属胁迫功能奠定了基础。

Glutathione S-Transferase(GST)Identified from Giant Kelp Macrocystis pyrifera Increases the Copper Tolerance of Synechococcus elongatus PCC 7942

The glutathione S-transferases gene family plays an important regulatory role in growth and development,and responses to environmental change.In this study,six complete GST genes(Mp GST1,Mp GST2,Mp GST3,MpGST4,Mp GST5,and Mp GST6)were cloned from the gametophytes of brown alga Macrocystis pyrifera.Subsequent bioinformatics analysis showed that these six genes encoded proteins with 202,216,288,201,205,and 201 aa,respectively.Moreover,Mp GST3 differs from the other GST genes.Phylogenetic analysis suggested that MpGST3 belongs to the Ure2p type GST.Domain analysis suggested that the other GSTs from M.pyrifera belong to the soluble GST family and form an independent branch with the GSTs found in the other macroalgae,suggesting that a new GST type was formed during macroalgal evolution.GST genes were upregulated in M.pyrifera when 2.5 mg L^(-1)Cu ions were added to the medium.Six GST genes were integrated into the genome of Synechococcus elongatus PCC 7942,and their functions were verified by measuring light absorbance,photosynthetic pigment content,and photosynthetic parameters of the transformed strains under 0.3 mg L^(-1)Cu ion stress.The results showed much higher levels of various parameters in the transformed strains than in the wild strain.The transformed strains(with the MpGST genes)showed significantly enhanced resistance to Cu ion stress,while the wild strain almost died.The results of this study lay a theoretical foundation for further research on the Cu ion stress resistance function of GSTs in M.pyrifera.

DNA条形码在渔业生物多样性保护中的应用

生物多样性与人类存亡休戚相关,保护生物多样性是实现人类社会可持续发展的基础。本文立足我国渔业生物多样性现状,针对我国渔业生物过度开发和保护不足等难题,提出了通过开展渔业生物DNA条形码研究来推动我国渔业生物多样性学科发展的思路,详细阐述了DNA条形码在渔业生物资源可持续开发、物种分类鉴定、生物多样性监测、外来物种评价、水产品市场监管、渔业信息化等多个领域的应用现状,进一步展望了DNA条形码可以成为渔业生物区系研究、水域生态研究、电子分类技术以及宏DNA条形码新技术等多个方面的研究热点,呼吁扎实推进我国渔业生物DNA条形码数据库和信息化平台的建设和共享。

Response of phytoplankton to multispecies mariculture:a case study on the carrying capacity of shellfish in the Sanggou Bay in China

A muhispecies model for shellfish polycuhure in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamysfarreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria japonica is presented. The model includes key physical processes which are the transports of matter at the system boundary, and the main biological process that is the primary production and nutrients release from the bottom. By the model, the seasonal fluctuations of phytoplankton biomass and dissolved inorganic nitrogen（DIN） in 1994 are simulated. Furthermore, if the kelp culture scale is kept constant and the Chinese scallop and the Pacific oyster culture scales are adjusted, virtual shellfish farms are funded and responses of phytoplankton to the largescale shellfish culture are simulated. According to these simulated results, the room limitation, and the hypothesis that shellfish will not grow well if the phytoplankton biomass is less than 8.2 mg/m^3 , the expandable multiple of scallop culture k and that of oyster culture y are determined as k = -0.276 5y ＋4.690 5 and 0.133 3k ＋0.006 6y≤0.667 5, where, k （ or y） is equal to 1, the culture scale of scallop （ or oyster） is 8.8 x 109 individuals （or 66 ha, with a density of 59 ind./m^2 ）, and the kelp culture scale is 3 300 ha with a density of 12 ind./m^2.

Cloning and sequence analysis of the partial sequence of the rbcL from Bryopsis hypnoides

The partial sequence of the rbcL from Bryopsis hypnoides, including the sequences of the upstream, extron and partial intron, was amplified by PCR and their sequences were determined. With Spinacia oleracea as the outgroup, neighbor-joining method and maximum parsimony method were used respectively to build phylogenetic trees according to the rbcL exon sequence among 13 species that were the typical species of six phyla. Two kinds of trees showed clearly that there were two groups among those species, the green lineage and the non-green lineage. And the relationships of algae in the green lineage were similar in the two trees but those in the non-green lineage were not consistent. Analysis of codon preference indicated that the codon preference of the rbcL exon of Bryopsis hypnoides distinctly differed from that of the relevant sequence of photosynthetic bacteria.

Genetic variability of half-smooth tongue sole Cynoglossus semilaevis populations using microsatellite markers

Ten highly variable microsatellite loci were performed in order to evaluate the genetic variability of wild and hatchery samples of half-smooth tongue sole Cynoglossu＇s semilaevis. A group of 200 genotypes belonging to four wild samples, Laizhou （LZ）, Weihai （WH）, Qingdao （QD）, Rizhao （RZ） and one hatchery sample, Mingbo （MB）, were screened. All of the： ten microsatellite loci screened in this study showed marked polymorphism. A total of 70 different alleles were observed over all loci. The number of alleles per locus ranged from 4.2 to 1006 the average of expected and observed heterozygosity ranged from 0.67 to 0.82, and from 0：77 to0.87 respectively. A total of 10, 16, 10, 11 and 5 unique alleles each were found in LZ, WH~ QD：RZ and MB populations. The effective number of alleles varied from 2.87 for HSTS_7 to 6.83 for HSTS_h. The number of average genotypes ranged from 6.0 for HSTS a to 15.4 for HSTS_h： As compared with the wild populations, the hatchery population, MB, showed significant genetic changes such as fewer alleles per locus （P〈0.05）, a smaller number of low frequency alleles （P〈0.05）, a small number of unique alleles and a small number of genotypes （P〈0.05）, all indicative of a reduction in genetic diversity.

Biomass,nutrient uptake and fatty acid composition of Chlamydomonas sp.ICE-L in response to different nitrogen sources

Nitrogen removal from media by microalgae provides the potential benefit of producing lipids for biodiesel and biomass. However, research is limited on algal growth and biomass under different nitrogen sources and provides little insight in terms of biofuel production. We studied the influences of nitrogen sources on cell growth and lipid accumulation of Chlamydomonas sp. ICE-L, one of a promising oil rich micro algal species. Chlamydomonas sp.ICE-L grown in NH_4 Cl medium had maximum growth rate. While the highest dry biomass of 0.28 g/L was obtained in media containing NH_4NO_3, the highest lipid content of 0.21 g/g was achieved under nitrogendeficiency condition with a dry biomass of 0.24 g/L. In terms of total polyunsaturated fatty acids（PUFAs）production, NH_4NO_3 and NH_4 Cl media performed better than nitrogen-deficiency and KNO_3 media.Furthermore, NH_4NO_3 and NH_4 Cl media elucidated better results on C18：3 and C20：5 productions while KNO_3and-N conditions were better in C16：0, C18：1 and C18：2, comparatively.

无机砷在海带中的富集及氧化胁迫效应

本研究采用海带孢子体幼苗为实验材料,分别用不同浓度的As(Ⅲ)和As(Ⅴ)(0.2、0.4、0.8、1.6μmol/L)培养液进行循环水养殖,以研究不同价态无机砷在海带中的积累以及对其抗氧化防御系统的影响。结果表明,高浓度砷暴露组中海带总砷含量较高,As(Ⅲ)暴露下海带中总砷含量随时间增加,在28 d时达到最大值;As(V)暴露下海带中总砷含量则呈先升高后下降的趋势,但28 d时除最高浓度组外均显著高于初始值(P<0.05)。实验结束时As(V)暴露组海带中总砷含量显著低于As(Ⅲ),说明无机砷暴露下海带孢子体幼苗对亚砷酸盐的积累大于砷酸盐。无机砷暴露下海带中过氧化氢(H_(2)O_(2))和丙二醛(MDA)含量随时间的延长分别呈先降低后升高和先降低后升高再降低的趋势,但所有处理组海带中H_(2)O_(2)和MDA含量均显著高于对照组(P<0.05),且随浓度的升高而升高。细胞中过氧化氢酶(CAT)活性在砷暴露下升高,但随暴露时间的延长,无机砷对酶活性产生了一定程度的抑制作用,酶活性降低。超氧化物歧化酶(SOD)活性在第1天时显著高于其他取样时间酶活性,随暴露时间的延长,砷影响减弱,SOD酶活性处于相对稳定状态,均显著高于对照组。海带能够积累海水中无机砷,且对As(Ⅲ)的积累能力较强,砷作用下虽然会对海带抗氧化防御系统产生一定的损伤,但其通过自我调节降低了砷的毒害作用。

Activities of principal photosynthetic enzymes in green macroalga Ulva linza:functional implication of C_4 pathway in CO_2 assimilation

The green-tide-forming macroalga Ulva linza was profiled by transcriptome sequencing to ascertain whether the alga carries both C3 and C4 photosynthesis genes.The key enzymes involved in C4 metabolism including pyruvate orthophosphate dikinase(PPDK),phosphoenolpyruvate carboxylase(PEPC),and phosphoenolpyruvate carboxykinase(PCK) were found.When measured under normal and different stress conditions,expression of rbcL was higher under normal conditions and lower under the adverse conditions,whereas that of PPDK was higher under some adverse conditions,namely desiccation,high salinity,and low salinity.Both ribulose-1,5-biphosphate carboxylase(RuBPCase) and PPDK were found to play a role in carbon fixation,with significantly higher PPDK activity across the stress conditions.These results suggest that elevated PPDK activity alters carbon metabolism in U.linza leading to partial operation of the C4 carbon metabolism,a pathway that,under stress conditions,probably contributes to the hardy character of U.linza and thus to its wide distribution.