Long interspersed elements in three species of Gracilaria （Gracilariaceae, Rhodophyta）

In order to find out whether long interspersed elements (LINEs) existed in macro-algae ge- nomes or not, we tested the LINE homologues in representative families (species): Gracilaria (G. eucheumoides Harv., G. tenuistipitata Chang et Xia, and G. textorii (Sur) De-Toni), Laminaria (L. longis- sima Miyabe and L. japonica Aresch.), and Ulva (U. lactuca L. and U. pertusa Kjellm.) during 2004 to 2005. Polymerase Chain Reaction (PCR) was carried out with degenerate oligonucleotide primers de- signed from LINEs of rice homologues and Cin4 of maize. Cloning and nucleotide sequencing of the PCR products revealed that 4 clones that derived from 3 species of Gracilaria have LINE homologues. The nucleotide sequences of the 4 LINE homologues diverged greatly, but the amino acid sequences deduced from them were relatively conserved. The endonuclease regions of the LINE homologues greatly di- verged from that of other plants, but they had closer phylogenetic relationship to Zepp elements in Chlor- ella sp., which indicated that sequence divergence by vertical transmission has been a major influence on the evolution of algal LINEs.     

3种星虫线粒体16S rRNA、COI和Cyt b基因片段的序列比较

对裸体方格星虫(Sipunculus nudus)、可口革囊星虫(Phascolosoma esculenta)和澳洲管体星虫(Siphonosoma australe)的线粒体16S rRNA、COI和细胞色素b(Cytb)基因片段序列进行比较,并对其系统发生进行了初步探讨。采用PCR方法得到总长度分别为531～544bp(16S)、652～675bp(COI)和406～453bp(Cytb)的线粒体片段。片段碱基A+T比例较高(16S rRNA基因58.3%,COI基因56.9%,Cytb基因59.5%)。16S rRNA片段存在169个碱基变异位点(其中包括167个简约信息位点)和44个碱基插入/缺失,种内个体间变异较小;COI片段有512个碱基(333个简约信息位点)存在变异,79个碱基插入/缺失;Cytb片段存在347个碱基(318个简约信息位点)变异位点,16个碱基插入/缺失。数据分析结果支持3种星虫和环节动物的分类地位较近,与软体动物较远的分类观点。此外,裸体方格星虫与澳洲管体星虫之间亲缘关系较近(D=0.3159、0.3156、0.2361)。认为3种星虫线粒体16S rRNA、COI和Cytb基因在种间存在明显的多态性,证实了三种基因序列均普遍适用于星虫种及以上阶元的系统学分析。     

口蹄疫病毒VP1植物表达载体的构建

P1 T重组质粒上含有口蹄疫病毒 (FMDV)GD10分离株的p1cDNA片段 ,以此为模板 ,用PCR方法扩增其中的VP1基因 ,获得大小约 6 40bp的片段。该片段用BglⅡ和BstEⅡ酶切消化后克隆至表达载体 pCAMBIA130 5 .2 ,转化EcoliTOP10感受态细胞。重组质粒经PCR、酶切及序列分析 ,证实VP1基因处于CaMV35S启动子控制 ,且读码框正确     

4株琼胶降解菌的分离、鉴定及产酶条件分析

从海藻及海参中分离筛选得到4株琼胶降解菌HD、JL、QJ和HS,均为革兰氏阴性菌,确定了它们发酵产酶的最佳条件均为：2216E海水培养基、初始 Ph 7.5、琼胶底物浓度0.30%、培养温度28℃、培养时间36 h。大部分酶分泌到细菌细胞外。生理生化检测、16SrDNA序列同源性及聚类分析结果表明, HD、JL、HS为白色噬琼胶菌(Agarivorans albus);QJ的16SrDNA序列与Simiduia sp.,糖噬胞菌属( Saccharophagus sp.)和船蛆杆菌(Teredinibacter sp.)的相似性为93%~94%,在进化树上单独形成一个分支,但生理生化特征与它们有所不同,分类地位需要进一步确定。从HD、JL和HS中能克隆到β-琼胶酶基因,它们与其他物种的β-琼胶酶基因序列的相似性为97%~98%。     

基于COI和ITS-1基因对魁蚶野生群体和人工繁育子代的遗传分析

采用线粒体 COI 基因和核糖体第一内转录间隔区 ITS-1基因,对荣成(RC)和即墨(JM)2个魁蚶(Scapharca broughtonii Schrenck)野生地理群体及一个人工繁育的即墨子代(JZ)群体,进行遗传多样性和遗传结构分析,探讨即墨人工繁育的子代作为荣成魁蚶底播增殖苗种的可行性。分子方差分析(AMOVA)结果表明,3个群体的遗传差异主要存在群体内。荣成野生群体和即墨野生群体间的Fst值,基于COI基因和ITS-1基因分别为0.1678和0.1193,表明荣成野生群体与即墨野生群体之间存在中等程度的遗传分化。单倍型多样性和核苷酸多样性分析结果表明,人工繁育的即墨子代群体的遗传多样性明显降低。荣成野生群体与即墨子代群体之间的遗传差异,较之与即墨野生群体间的遗传差异更大。如果采用即墨子代在荣成底播,可能会对荣成野生魁蚶野生群体的遗传结构产生一定影响,因此,采用即墨人工繁育子代作为荣成魁蚶底播增殖的苗种来源时必须十分慎重,并在苗种繁育时尽量采用大群体有效亲本。     

Asexual origin of brooding in the sea anemones Actinia equina and A. schmidti: molecular evidence from the Portuguese shore

Reproduction by sexual or asexual viviparity is a common phenomenon in some anemone species. In this short communication, the origin of the brooded young of Actinia equina and A. schmidti from the Portuguese shore was investigated. DNA was extracted from 56 brooding adult Actinia sp. and the nuclear gene that codes for the 28S ribosomal subunit was sequenced. Species identity was then assessed using GenBank. In total, 50 individuals were A. schmidti, five were A. equina and one had a hybrid origin. Three adult anemones (the hybrid, one A. equina and one A. schmidti) possessed two different 28S sequences and so their offspring was selected for further analysis using the same molecular procedure. Each brooded polyp was found to possess the exact same sequence as its parent, strongly suggesting the asexual origin of broods in A. equina and A. schmidti.     

根癌农杆菌(Agrobacterium tumefaciens)介导培育富含叶黄素的基因工程小球藻(Chlorella vulgaris)的研究

采用基因克隆技术构建双元载体pCAMBIA2301-idi,通过电转转入农杆菌LBA4404中.利用根癌农杆菌介导的转化方法,将pCAMBIA2301-idi质粒的T-DNA区转入小球藻,以G418抗性基因(NPTⅡ)作为筛选标记,筛选出阳性转化子.通过PCR扩增表明idi基因和NPTⅡ基因已经整合到小球藻基因组中.测定转化子的生物量,结果表明大部分转化子的生物量与野生型相似.测定转化子小球藻干粉的叶黄素含量,发现转化子叶黄素含量最高达到0.84mg/g,与野生型相比提高了30.95％.进一步分析藻液中叶黄素的产量,发现转化子的叶黄素产量最高达到1.98mg/L,比野生型提高了36.77％.     

Biochemical‐genetic variation in a wild and a cultured population of the greenshell mussel,Perna canaliculus

A wild and a cultured greenshell mussel (Perna canaliculus) population were compared for biochemical genetic variation at seven polymorphic and four monomorphic allozyme loci. Significant heterozygote deficiencies were observed for all polymorphic loci (La—1, La—2, Lap, Lgg—1, Lgg— 2, Pgi, and Pgm) for both populations (except the Pgi locus of the wild mussel population). Genotypic disequilibrium was calculated for both populations: genotypic frequencies were significantly non‐random at three pairs of loci among the wild mussels, and significantly non‐random at three different pairs of loci among the cultured mussels. All six pairs of loci which exhibited significant genotypic disequilibrium involved amino‐peptidases, suggesting that these loci form a linkage group, and that neither the Pgi nor the Pgm loci are associated with this group. Exact tests for population differentiation based upon population‐specific allele distributions indicated that four of the polymorphic loci were significantly heterogeneous among the two populations, whereas the remaining three polymorphic loci were not. Based upon the private allele system, the number of migrants (N _m) between the populations was estimated to be 2.009, which, according to the private allele system, represents a high level of gene flow. These findings are discussed with regard to the population biology and genetic structure of this species.