2个水稻花发育相关MADS-box基因的全序列cDNA克隆及结构分析

一组具有MADS-box结构域的转录因子在控制花器官的诱导与发育中起着重要作用．以水稻广陆矮4号(Oryza sativa L．Guang-Lu—Ai No．4)幼穗总RNA为模板,根据MADS-box保守区的序列设计简并性引物。利用3′-RACE的方法获得了2个新的水稻花发育相关MADS-box基因,分别命名为FDRMADS3和FDRMADS4;并利用5′-RACE的方法获得了该2个基因完整的cDNA序列,包括完整的编码区,5′-UTR和3′-UTR．它们编码的蛋白质都具有典型的MADS-box结构域和半保守的K区,其与水稻中其他家族成员的MADS-box结构域同源性高达90％以上,这说明它们都是典型的MADS-box基因．     

冷水鱼固着类纤毛虫PCR检测方法探讨及感染因素分析

针对冷水鱼养殖中固着类纤毛虫检测难和污染源不明确、种类鉴定难的问题,对冷水鱼养殖环境中固着类纤毛虫的主要寄生种类及感染因素进行调查分析,在不同季节于河北省内采集冷水鱼和水环境样本。首先,采用形态学方法对鱼体及水环境中的固着类纤毛虫进行初步鉴定;然后,建立PCR方法进行分子水平鉴定,并进行系统发育学分析;最后,对冷水鱼感染寄生虫的原因进行分析。形态学鉴定结果表明,冷水鱼寄生的固着类纤毛虫主要有累枝虫(Epistylis sp.)和钟虫(Vorticella sp.)2类;引物设计、敏感性和特异性试验结果显示,建立的寄生虫PCR检测方法有效,测序比对和系统发育分析结果进一步验证了其形态学结果;运用已建立的PCR方法检测出固着类纤毛虫在水环境中高达94.38%,鱼体广泛寄生,感染率达到了100%;且无季节差异,水体中的虫体可能是造成鱼长期感染的原因之一。研究数据可为冷水鱼病害的科学预测、预防和治疗提供依据,同时为冷水鱼养殖产业的可持续发展提供疫病防治参考。     

植物功能性状系统发育保守性的类群和地理分异研究——以中国被子植物最大株高为例

【目的】株高是植物生态策略的核心部分。本研究旨在揭示中国被子植物最大株高的系统发育保守性,探明其类群、地理分异规律及与环境因子的关联。【方法】利用中国20 295种被子植物的最大株高和地理分布数据,检测不同生长型、不同类群和不同植被区域植物最大株高的系统发育保守性,分析系统发育信号(Pagel'sλ值)与纬度、温度和降水量等因子的关联。【结果】中国被子植物最大株高的系统发育保守性较强(Pagel's λ=0.893)。其中,草本植物的系统发育保守性程度略低于木本植物,豆目(Fabales)、石竹目(Caryophyllales)、天门冬目(Asparagales)、唇形目(Lamiales)、伞形目(Apiales)、虎耳草目(Saxifragales)等6个目的系统发育信号均高于0.9。所有被子植物与木本植物的系统发育信号与纬度、温度均呈单峰曲线关系,但与降水量呈负相关。草本植物系统发育信号的纬度格局不明显,与温度、降水量均呈多峰曲线关系。【结论】中国被子植物最大株高的系统发育保守性具有明显的地理格局,但趋势因生长型而异。总体来说,中纬度地区被子植物整体及木本植物株高的系统发育保守性强于高、低纬度地区。     

果胶酶高产菌株EIM-6的筛选鉴定及其液体发酵产酶条件优化

通过筛选得到一株适合液体深层发酵培养的高产果胶酶菌株EIM-6,基于形态学与ITS序列分子系统进化分析,鉴定为Aspergillus niger.运用单因子实验确定EIM-6产果胶酶最适碳源和氮源.在此基础上,通过Plackett-Burrman设计对影响其产酶的相关因素进行评估并筛选出具有显著效应的3个因素.然后通过最陡爬坡实验在上升最高点处由中心组合实验和响应面分析确定其最适产酶条件.实验优化的最优产酶条件为:w(橘皮粉)4.09%,w(麸皮)3.16%,w((NH4)2SO4)0.35%,w(K2HPO4)0.3%,w(CaCO3)0.24%,初始pH 6,接种量107/mL,转速250 r/min,28 ℃培养80 h酶活达30 231 U/mL,与初始相比,酶活提高2.07倍.     

多足动物系统发生的研究进展

介绍多足动物分子系统学、发育生物学、比较形态学等方面的研究情况及近年的研究进展,探讨多足类与节肢动物门内其他类群间的关系,以及多足类动物的单系性问题。     

Phylogenetic position of Schnabelia, a genus endemic to China： Evidence from sequences of cpDNA matK gene and nrDNA ITS regions

The chloroplast gene matK and the internal transcribed spacers (ITS) of the nuclear ribosomal DNA from Schnabelia, a genus endemic to China, and 6 genera of Verbenaceae and 13 genera of Lamiaceae were sequenced. The phylogenetic signal and validity outgroups were measured and evaluated by means of the relatively apparent synapomorphy analysis (RASA). Independent and combined phylogenetic analyses for the matK and ITS sequences were performed using the maximum parsimony (MP), neighbor-joining (NJ) and maximum likelihood (ML) methods, indicating that Schnabelia oligophylla and Caryopteris terniflora form a sister-group relationship. The Caryopteris complex is not shown to be a monophyly because Trichostema, C. paniculata and C. forrestii are paraphyletic to the clade containing the remaining members of the complex. A monophyly of Ajugoideae proposed by Cantino et al., including 8 genera in this study, is strongly supported and the closest relatives of Schnabelia are in the Ajugoideae (Lamiaceae), especially near Caryopteris terniflora. The polygenetic analyses also showed that the genera of Lamiaceae and Verbenaceae sampled in this tudy are phylogenetically mixed and the genus Avicennia is distant to other genera of Verbenaceae. RASA and combined analysis can be used as effective approaches to determining the relationships among phylogenetically complex groups.     

2,3-Dihydroxybiphenyl dioxygenase gene was first discovered in Arthrobacter sp. strain PJ3

Bacterium strain PJ3,isolated from wastewater and identified as Arthrobacter sp. bacterium based on its 16S rDNA gene,could use carbazole as the sole carbon,nitrogen and energy source. The genomic library of strain PJ3 was constructed and a positive clone JM109(pUCW402) was screened out for the expression of dioxygenase by the ability to form yellow ring-fission product. A 2,3-dihydroxybiphenyl dioxygenase(23DHBD) gene of 933 bp was found in the 3360 bp exogenous fragment of pUCW402 by GenSCAN software and BLAST analysis. The phylogenetic analysis showed that 23DHBD from strain PJ3 formed a deep branch separate from a cluster containing most known 23DHBD in GenBank. Southern hybridization confirmed for the first time that the 23DHBD gene was from the genomic DNA of Arthrobacter sp. PJ3. In order to test the gene function,recombinant bacterium BL21(pETW-8) was constructed to express 23DHBD. The expression level in BL21(pETW-8) was highest compared with the recombinant bacteria JM109(pUCW402) and strain PJ3. We observed that 23DHBD was not absolute specific. The enzyme activity was higher with 2,3-dihydroxybiphenyl as a substrate than with catechol. The substrate specificity assay suggested that 23DHBD was essential for cleavage of bi-cyclic aromatic compounds during the course of aromatic compound biodegradation in Arthrobacter sp. strain PJ3.     

Phylogenetic relationships of native and introduced Bemisia tabaci (Homoptera:Aleyrodidae) from China and India based on mtCOI DNA sequencing and host plant comparisons

Phylogenetic relationships for Bemisia tabaci were reconstructed by analysis of a ～780 bp fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene with an emphasis on geographic range and distribution among eight eudicot plant families that are common hosts of B. tabaci worldwide to elucidate key phylogeographic linkages between populations extant in China (n=31) and India (n=34). Bootstrap values for the Maximum Parsimony tree were highly robust for all major nodes involving the major Asian clade, subgroups, and sister groups within, at 92%—100%. Between-clade distances for the Southeast Asia and three other major clades, e.g. from sub-Sahara Africa, North Africa-Mediterranean, and the Americas, were approximately >16% divergent. Two major Asian subgroups (I, II) were resolved, which represented populations indigenous to the region, comprising two (I a, I b) and five (II a—e) sister groups, respectively, which diverged by 11%. Two distinct populations from sunflower in Hyderabad grouped separately within the two Asian subgroups. All other populations grouped uniquely within Asian subgroup II or I. The “B” biotype was identified in 23 collections from China at 97.3%—99.5% nucleotide identity with “B” biotype reference sequences; it was not identified in collections from India. The majority of haplotypes were associated with 3—4 plant families, with one exception that for sister group IId (sesame, India), it might be monophagous. Thus, B. tabaci from the southeastern and near eastern regions of the Asian continent comprise of a large number of ancestral, richly divergent, mostly polyphagous populations. This region is therefore hypothesized to constitute an important Old World center of diversification for the B. tabaci complex, together with sub-Saharan Africa.     

黑线仓鼠AVP基因部分序列的系统进化及结构分析

根据GenBank中黑线仓鼠（Cricetulus barabensis）同源物种的AVPcDNA序列设计引物,利用RT-PCR技术得到了黑线仓鼠精氨酸加压素（AVP）基因部分cDNA序列,包括外显子2的全部序列和外显子1、3的部分序列,共433bp,并注册到GenBank（登录号：JN227681）。该段序列共编码143个氨基酸,二级结构预测显示片段中含较多的a螺旋。该序列与其他物种相应区域的比较结果表明其同源性为84％～92％,氨基酸序列同源性为82％-93％。系统进化分析结果与物种亲缘关系的远近一致,该序列的克隆为研究AVP的表达调控机制奠定了基础,将有助于AVP的作用机制的研究及功能分析,同时该cDNA序列可作为物种亲缘关系或遗传距离研究的理想标记。     

西藏冬虫夏草无性型5.8S rDNA,ITS间区系统发育分析

 采用相对较低的培养温度(5~12℃),从西藏那曲当年产风干冬虫夏草[Cordyceps sinensis(Berk.)Sacc.]分离得到菌株C21,综合其菌丝形态学特征及5.8S rDNA和ITS间区的系统发育分析结果,证实菌株C21为冬虫夏草菌的无性型,即中国被毛孢(Hirsutella sinensis).