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1.
采用聚丙烯酰胺凝胶电泳技术,从西大西洋笛鲷（Lutjanuscampechanus）和勒氏笛鲷（L．russel—lii）的微卫星引物中筛选出适用于孟加拉笛鲷（L．bengalensis）和四带笛鲷（三．kasmira）的微卫星引物,并应用于三亚和湛江群体的遗传结构分析．结果表明：25对引物中筛选出13对可以稳定扩增出特异片段的引物,其中12对可在孟加拉笛鲷基因组中扩增出重复性好的特异性条带;10对可在四带笛鲷中扩增出重复性好的特异性条带,并且全部呈现出种内多态;9对为两个种通用．孟加拉笛鲷的湛江群体（zMJ）和三亚群体（SMJ）、四带笛鲷的湛江群体（ZSD）和三亚群体（SSD）的平均等位基因数分别为：3．8889、4．1111、4．3333、4．2222;平均观测杂合度分别为：0．5833、0．6389、0．5944、0．6389;平均多态信息含量分别为：0．4720、0．4692、0．5474、0．5257．将本实验所得结果与笛鲷鱼其他研究结果进行比较分析,可以看出目前湛江海域野生笛鲷的遗传多样性整体比较丰富,但部分野生笛鲷已表现出杂合子缺失的趋势,这势必会引起将来遗传多样性的降低,所以要尽旱对野生群体进行摸底调查。并找出解决养殖群体污染野生群体这一问题的方法． 相似文献
2.
LIU Yong YANG Guanpin WANG Hualei CHEN Jixiang SHI Xianming ZOU Guiwei WEI Qiwei SUN Xiuqin 《中国海洋大学学报(英文版)》2006,5(2):157-164
The pathogenic species of genus Vibrio cause vibriosis, one of the most prevalent diseases of maricultured animals and seafood consumers. Monitoring their kinetics in the chain of seafood production, processing and consumption is of great importance for food and mariculture safety. In order to enrich Vibrio-representing 16S ribosomal RNA gene （rDNA） fragments and identify these bacteria further real-timely and synchronously among bacterial flora in the chain, a pair of primers that selectively amplify Vibrio 16S rDNA fragments were designed with their specificities and coverage testified in the analysis of seawater Vibrio community. The specificities and coverage of two primers, VF169 and VR744, were determined theoretically among bacterial 16S rDNAs available in GenBank by using BLAST program and practically by amplifying Vibrio 16S rDNA fragments from seawater DNA. More than 88.3% of sequences in GenBank, which showed identical matches with VR744, belong to Vibrio genus. A total of 33 clones were randomly selected and sequenced. All of the sequences showed their highest similarities to and clustered around those of diverse known Vibrio species. The primers designed are capable of retrieving a wide range of Vibrio 16S rDNA fragments specifically among bacterial flora in seawater, the most important natural environment of seafood cultivation. 相似文献
3.
Impulsive time-free transfers between halo orbits 总被引：1，自引：0，他引：1
A methodology is developed to design optimal time-free impulsive transfers between three-dimensional halo orbits in the vicinity of the interior L
1 libration point of the Sun-Earth/Moon barycenter system. The transfer trajectories are optimal in the sense that the total characteristic velocity required to implement the transfer exhibits a local minimum. Criteria are established whereby the implementation of a coast in the initial orbit, a coast in the final orbit, or dual coasts accomplishes a reduction in fuel expenditure. The optimality of a reference two-impulse transfer can be determined by examining the slope at the endpoints of a plot of the magnitude of the primer vector on the reference trajectory. If the initial and final slopes of the primer magnitude are zero, the transfer trajectory is optimal; otherwise, the execution of coasts is warranted. The optimal time of flight on the time-free transfer, and consequently, the departure and arrival locations on the halo orbits are determined by the unconstrained minimization of a function of two variables using a multivariable search technique. Results indicate that the cost can be substantially diminished by the allowance for coasts in the initial and final libration-point orbits.An earlier version was presented as Paper AIAA 92-4580 at the AIAA/AAS Astrodynamics Conference, Hilton Head Island, SC, U.S.A., August 10–12, 1992. 相似文献
4.
JD Klein AE Bester-van der Merwe ML Dicken A Emami-Khoyi KL Mmonwa 《African Journal of Marine Science》2019,41(1):115-118
Genomic data can be a useful tool in the management and conservation of biodiversity. Here, we report the development of genomic resources for the spotted ragged-tooth shark Carcharias taurus using genome-wide DNA data from Illumina next-generation sequencing. We explored two commonly used genetic marker types: microsatellites and mitochondrial DNA. A total of 4 394 putative microsatellites were identified, of which 10 were tested on 24 individuals and found to have ideal properties for population genetic analyses. Additionally, we reconstructed the first complete mitochondrial genome of a South African spotted ragged-tooth shark, and highlight the most informative gene regions to facilitate future primer design. The data reported here may serve as a resource for future studies and can ultimately be applied in the sustainable conservation and fisheries management of this apex predator. 相似文献
5.
Primers to block the amplification of symbiotic apostome ciliate 18S rRNA gene in a PCR-based copepod diet study 总被引：1，自引：0，他引：1
Pelagic copepods play an important role in the marine food web. However, a full understanding of the ecological status of this zooplankton group depends on the careful study of their natural diets. In previous PCR-based copepod diet studies, we found many apostome ciliates that live symbiotically under the exoskeleton of the copepods, and their sequences were often over-represented in the 18S rRNA gene （18S rDNA） libraries. As a first step to address this issue, we designed three apostome ciliate 18S rDNA blocking primers, and tested their blocking efficiency against apostome ciliate 18S rDNA under various PCR conditions. Using a semi-quantitative PCR method, we optimized the conditions to efficiently amplify the 18S rDNA of the prey while simultaneously excluding the symbiotic apostome ciliates. This technique will facilitate PCR-based diet studies of copepods and other zooplankton in their natural environments. 相似文献
6.
利用台湾报道的ＷＳＢＶ的ＰＣＲ引物，成功地扩增出了１４００ｂｐ左右的中国对虾的杆状病毒的ＤＮＡ片段，与预计的产物长度吻合。该引物对经初步离心处理的病虾组织也能扩增出特异性ＤＮＡ条带，而对正常虾组织ＤＮＡ、昆虫杆状病毒（ＡｃＭＮＰＶ）ＤＮＡ进行扩增，均获得阴性结果。说明该引物的特异性较高，对中国对虾的杆状病毒的检测具有一定的实际应用价值。实验结果同时说明ＷＳＢＶ与中国对虾的杆状病毒有同源序列存在，具有一定的保守性；用该引物进行的ＰＣＲ扩增为中国对虾的杆状病毒与其他相关病毒的比较研究提供了一种技术手段。 相似文献
7.
桡足类是海洋生态系统中初级生产者和较高营养级消费者之间的关键联系环节,掌握桡足类的现场食物组成对于准确评估海洋食物网中的营养关系和能量转移至关重要。本研究中,我们以中华哲水蚤这一在中国、日本以及韩国近海具有重要生态地位的大型哲水蚤属桡足类为研究对象,应用之前开发的基于PCR的克隆技术,通过分析中华哲水蚤所摄食生物的18S rDNA序列,研究了中华哲水蚤的现场食物组成。结果揭示了南黄海（Y19站位）和渤海（B49站位）中华哲水蚤食物组成的多样性。共检测出43个操作分类单元（OTUs）,分别隶属于13个类群：硅藻（Bacillariophyta）、甲藻（Dinoflagellata）、硅鞭藻（Dictyochophyceae）、金藻（Chrysophyta）、Katablepharidophyta、浮生藻（Pelagophyceae）、无根虫（Apusozoa）、水螅水母（Hydrozoa）、栉水母（Ctenophora）、棘皮动物（Echinodermata）、被囊动物（Tunicata）、毛颚动物（Chaetognatha）以及海洋真菌。结果还表明,当发生藻类暴发时,中华哲水蚤可以摄食引发藻类暴发的藻种。当周围海域浮游植物的丰度相对较低时,中华哲水蚤可以选择摄食各种后生动物尤其是水螅水母和栉水母的卵、幼虫或者有机碎屑。我们的研究结果表明中华哲水蚤是一种杂食性桡足类,它对食物的选择依赖其生活海域中食物的可获得性。 相似文献
8.
摘要：采用聚丙烯酰胺凝胶电泳技术，从20对西大西洋笛鲷（Lutjanus campechamus）的微卫星引物中筛选适用于红鳍笛鲷（L．erythopterus）、勒氏笛鲷（L.russellii）、紫红笛鲷（L.argentimaculatus）和约氏笛鲷（L.johnii）基因组分析的微卫星引物，分析4种笛鲷的遗传多样性及系统发生。经反应条件的优化，从20对引物中筛选出17对可稳定扩增出特异片段的引物。通过测序证实扩增产物含微卫星位点后，以该17对引物对4个种的群体进行遗传多样性分析。其中16对可在约氏笛鲷、勒氏笛鲷、紫红笛鲷基因组中扩增出重复性好的特异性条带，分别有65％、65％、60％呈现出种内多态：15对可在红鳍笛鲷中扩增出重复性好的特异性条带，并且全部呈现出种内多态。四种笛鲷中，红鳍笛鲷的多态性最高，高度多态基因座占检测座位的66．67％；勒氏笛鲷的多态性最低，低度多态基因座占43．75％。获得3个种间特异性分子标记。用风和DA两种方法计算4种笛鲷的遗传距离，构建了系统发生树。 相似文献
9.
海藻共附生细菌密切参与宿主的生长发育、营养吸收等重要过程,浒苔(Ulva prolifera)是构成黄海绿潮的唯一优势种,对其共附生细菌开展群落结构分析,有望为成灾机制研究提供重要线索。由于植物叶绿体基因组同时具备原核特征和高拷贝数,会严重干扰共附生细菌基于16S rDNA的序列扩增。高等植物中开发了通用引物799F,利用其3′末端与植物同源区的非配对双碱基,可实现对细菌来源序列的特异性扩增。本文针对多个浒苔群体样本,首次评价了引物799F在藻类中的适用性,发现799F的3′末端与浒苔叶绿体同源区仅存在非配对单碱基,其扩增仍会受到浒苔叶绿体严重干扰。在引物799F的基础上,设计了新引物800F,与通用反向引物1492R配对扩增细菌16S rDNA中具高分辨率的V5-V9可变区,配合使用具热启动功能、同时不具校对功能的DNA聚合酶,可基本完全避免浒苔叶绿体来源序列的扩增,并阐明了方法的原理。优化的引物扩增方案可用于浒苔共附生细菌群落结构分析。 相似文献
10.
为了解日本囊对虾（Marsupenaeusjaponicus）性腺发育及分化的分子机制,本研究采用改良的引物退火控制技术克隆到了共8个精巢、卵巢的差异表达基因．其中4个为已知基因,分别为凝血酶敏感蛋白基因、皮质棒蛋白基因、增殖细胞核抗原基因和泛素缀合酶基因;4个为未知基因,分别命名为MjACP3-T、MjACP4一T、MjACPl5一T和MjACP4一O基因．采用实时定量PCR方法分析了4个未知基因在性腺发育过程的表达谱,结果表明：MjACP3一T、MjACP4．T和MjACPl5,T基因在日本囊对虾精巢和卵巢中的表达量有显著差异,且在各个时期精巢的表达量均高于卵巢,说明这3个基因可能在精巢的发育中起到某些重要作用．卵巢MjACP4一O基因的表达量变化较大,第5期卵巢的相对表达量达到最高（为1．38）,而其他各个阶段的变化较大,在第4期卵巢的相对表达量最低（为0．03）．在精巢中,MjACP4一O基因的表达量随着精巢逐渐发育成熟呈下降趋势．定量PCR结果与引物退火控制技术的结果有着很好的一致性．研究结果表明,引物退火控制技术是一种简单高效的克隆差异表达基因的技术．采用该技术所克隆到的8个精巢、卵巢的差异表达基因,为进一步了解日本囊对虾性腺发育分化的分子机制提供了基础材料． 相似文献