新疆枸杞种质资源遗传多样性的SRAP分析

利用SRAP分子标记技术对新疆枸杞种质资源遗传多样性及亲缘关系进行研究,为新疆枸杞种质资源分类和杂交育种提供理论依据。结果显示:(1)筛选出的12对SRAP引物共扩增出310个位点,其中多态性位点264个,多态性比率平均为84.61%,引物多态性信息含量(PIC)变化范围为0.76~0.93,平均为0.83;观测等位基因(Na)、有效等位基因数(Ne)、Neis基因多样性指数(H)、Shannon信息指数(I)平均值分别为1.846 1、1.386 9、0.228 0和0.352 0。(2)聚类分析表明,供试材料间的遗传相似系数为0.590 3~0.903 2,在遗传相似性系数为0.70和0.76时,可将30份样品分别分为2大类和5个亚类;主坐标分析结果和聚类结果基本一致。研究表明,新疆枸杞种质资源遗传多样性较丰富,且野生种与栽培品种(系)间的遗传差异较大,表现出较远的亲缘关系,而栽培品种(系)间的遗传差异相对较小,表现出较近的亲缘关系。     

中国灌木辣椒种质遗传多样性的SRAP和SSR分析

应用SRAP和SSR分子标记对8份辣椒种质进行了遗传多样性分析,结果表明,15对SRAP引物组合共扩增出321条带,平均每对引物扩增出21.40条,多态性位点比率为72.90%;18对SSR引物共扩增出109条带,平均每对引物扩增出6.06条,多态性位点比率为98.17%。与SRAP比较,SSR检测到的Shannon多样性指数(I)、观测等位基因数(Na)和有效等位基因数(Ne)等遗传多样性参数都较大,说明SSR有更高的多态性检测效率。基于SRAP的聚类与基于SSR的聚类之间存在极显著正相关,且都能将中国灌木辣椒种质与美洲灌木辣椒种质及一年生辣椒种质有效区分。     

中型狼尾草种质资源遗传多样性的ISSR分析

运用ISSR标记对采自云南的25份野生种质和4份驯化新品系中型狼尾草材料进行遗传多样性分析。结果显示:(1)50条ISSR引物中共筛选出10条能扩增出清晰条带且多态性明显的引物,29份材料DNA共获得72个扩增位点,其中多态性位点62个,多态性比率为87.4%,平均每条引物扩增位点为7.2个;平均观察等位基因数(Na)、有效等位基因数(Ne)、Shannon多样性信息指数(I)和Nei’s基因多样性指数(H)分别为1.861 1、1.742 8、0.561 0和0.395 9;种质材料间的遗传相似性系数变幅为0.236~0.903,表现出丰富的遗传多样性。(2)利用UPGMA聚类分析,以遗传相似系数0.51为界,29份材料划分为4大类,但Mantel检测表明29份种质材料的遗传聚类和地理距离之间不存在显著的正相关关系(r=0.437 0,P=0.204 6)。研究结果首次从分子水平揭示了中型狼尾草的遗传多样性和变异水平,为合理地引种、驯化、保护和利用中型狼尾草野生资源提供了重要的参考依据和数据支持。     

利用SRAP标记研究四川高原青稞育成品种的遗传多样性

利用SRAP(Sequence-related Amplified Polymorphism)分子标记技术, 对25份来自四川高原的青稞育成品种进行了遗传多样性研究。结果表明: 64对引物组合共检测出999条清晰条带, 62对可以获得多态性条带, 多态性引物组合占96.9%, 共产生225条多态性条带, 占总条带数的22.5%。64对引物组合共扩增出333种等位变异, 平均每个引物组合检测到5.20种等位变异。遗传多样性在0(me9/em14, me9/em15)~0.8928(me6/em18)之间, 平均为0.5126。聚类分析结果表明, 25份材料可分成A、B、C 3大类, 材料聚类与其来源地有明显的相关性。25份材料间的平均遗传距离较小(0.3240), 平均遗传多样性较低(0.5126), 遗传基础较为狭窄。     

青钱柳种质资源多样性SRAP初步分析

为了利用分子标记方法评价青钱柳种质资源的遗传多样性,本文对青钱柳DNA的提取、SRAP扩增体系重要参数进行了优化,运用优化体系筛选多态性引物,并用1对引物对青钱柳9个种源进行了遗传多样性初步分析.研究结果建立了适于青钱柳SRAP的扩增体系;从110对SRAP引物中筛选出了13对多态性引物,运用1对引物组合Me7+Em2扩增获得21个多态性位点,多态率达100%.遗传多样性分析表明有效等位基因数(Ne)为1.342 9,平均Shannon's信息指数(I)为0.368 7,Nei's基因多样性指数(H)为0.226 7,种源的遗传分化指数Gst为0.198 3;聚类分析结果表明9个种源在遗传距离0.100处聚为3类,聚类结果和地理距离之间呈现较高的相关性.本文的研究结果表明所建立的青钱柳种质资源库具有广泛的遗传多样性,为进一步的开发利用提供了条件.     

山药种质资源的ISSR分析及初级核心种质库的构建

采用ISSR分子标记技术对中国不同产地的35份山药种质资源进行遗传多样性分析,并用最小遗传距离逐步抽样法构建核心种质库。结果表明:(1)筛选出12个有效引物共扩增出142个位点,多态性比率为97.18%,平均Shannon’s信息指数(I)为0.4230,平均Nei’s基因多样性指数(h)为0.269 4,平均有效等位基因数(Ne)为1.427 1,平均等位基因数(Na)为1.971 8,说明35份山药种质遗传多样性很丰富。(2)聚类分析表明,种质间的遗传相似系数介于0.54~0.97之间,其中来源地不同的个别种质间的遗传相似系数也很高。(3)经6次逐步抽样,随着抽取种质数目的减少,种质库遗传多样性参数变化不明显,而多态性比率在其中5次逐步抽样中呈现下降趋势;但抽样4在抽样数是抽样前的31%时,多态位点率仍可达到抽样前的97.8%,说明抽样4所构建的山药核心种质库最具代表性。     

胡麻种质资源遗传多样性及亲缘关系的SRAP分析

利用SRAP分子标记,对国内外5个不同地区161份胡麻种质资源的遗传多样性及亲缘关系进行研究,为胡麻育种提供科学依据。结果表明:(1)20对引物扩增出307个条带,其中有192个多态性条带,多态比率为62.54%,平均每对引物组合有9.60个多态性位点,每对引物的多态性信息量(PIC)为0.51~0.76,平均为0.61。(2)有效等位基因数(Ne)、香浓信息指数(I)和Neis遗传相似系数(H)在物种水平上分别为1.582 0、0.521 1和0.346 5,在群体水平上分别为1.491 1、0.431 1和0.286 3。(3)各群体遗传多样性指数表现为中国西北群体中国华北群体美洲群体亚洲群体欧洲群体。(4)聚类分析结果显示,在遗传相似系数为0.335 5处,将161份胡麻资源分为2大类;在0.455 0处,分为5个亚类,与国内外5个不同地区来源吻合。研究表明,中国西北地区胡麻品种(系)的遗传多样性最为丰富;地域是影响胡麻种质资源遗传多样性的主要因素;国内、外品种(系)间的遗传差异较大,表现出较远的亲缘关系。     

河北省冬小麦品种SSR标记遗传多样性分析

利用79对多态性较高的SSR引物,对河北省1997-2007年间审定的冬小麦品种及国家小麦区试抗旱对照品种晋麦47和洛旱2号,共计87个冬小麦品种进行遗传多样性分析。79对SSR引物共检测出175个等位变异位点,每对引物可产生1~6条等位变异位点,平均2.215条。标记位点多态性信息含量(PIC)变幅为0.824~0.998,平均为0.941;有效等位基因数(Ne)变幅为1.644~20.333,平均4.708;香农指数(H’)变幅为0.148~1.102,平均为0.544,说明河北省冬小麦品种SSR遗传多样性较低。品种间遗传相似系数(GS)变幅为0.184~0.899,平均为0.418,其中河农826与石家庄8号间的遗传相似性最高,GS高达0.899,71-3与藁优9618间的遗传相似性最低,GS为0.184。不同育种单位培育的小麦品种平均遗传相似系数存在较大差异。UPGMA遗传相似性聚类表明,石家庄市小麦新品种新技术研究所培育的小麦品种与其他单位品种存在较大的遗传差异。     

基于SRAP标记的甜瓜耐盐种质资源遗传多样性分析

研究不同耐盐程度甜瓜种质资源的亲缘关系和遗传多样性,为甜瓜种质资源有效利用提供理论依据。该试验以不同耐盐程度的27个甜瓜品种为材料,利用SRAP标记分析甜瓜种质资源的遗传多样性,从364对引物组合中筛选出24对扩增清楚且多态性丰富的引物,共扩增出415个清晰的位点,其中多态性位点241个,多态比率达58%。平均观测等位基因数(Na)为1.588 0,平均有效等位基因数(Ne)为1.347 0,平均Nei's基因多样性指数(H)为0.201 3,平均Shannon's信息指数(I)为0.301 0,表明供试甜瓜具有丰富的遗传多样性。UPGMA聚类结果显示:遗传相似系数在0.36～1.00之间,遗传相似性系数在0.72时,可将27个甜瓜品种划分为4个类群,耐盐型甜瓜在其中3个类群有分布,中等耐盐型甜瓜在4大类群中均有分布,盐敏感型均集中在第Ⅰ类群,表明耐盐型和中等耐盐型甜瓜种质的遗传多样性比盐敏感型种质丰富。遗传相似系数与UPGMA聚类结果的Cophentic矩阵相关系数为0.749,说明聚类分析结果较准确。研究认为,耐盐型甜瓜的遗传多样性较丰富,要得到耐盐的杂种优势品种,需要融入更多遗传关系较远的新种质。     

基于ISSR分子标记的郁金香品种遗传多样性分析

本研究利用ISSR分子标记技术对22个郁金香品种进行遗传多样性分析,以期了解郁金香不同品种之间的遗传关系,提高育种的目标性。利用11条引物共扩增出129条谱带,其中多态性谱带为124条,多态性率为96.1%,22个郁金香品种的检测等位基因数(na*)平均为1.983 9,有效等位基因数(ne*)平均为1.383 3,Nei's基因多样性指数(h*)平均为0.249 0,Shannon's信息指数(I*)平均为0.399 0,表明郁金香多态性较高,具有丰富的遗传多样性。利用NTSYS软件进行UPGMA聚类分析,22个品种在遗传相似系数0.62为阈值处可分为两大类,根据聚类结果,理论上推测不同花色的品种间杂交获得新品种的潜力较大。此结论为进一步研究和利用郁金香提供分子水平的依据。     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Analysis of twin of eyeless regulation during early embryogenesis in Drosophila melanogaster

The Drosophila Pax6 homolog twin of eyeless (toy) is so far the first zygotically expressed gene involved in eye morphogenesis in Drosophila. The study of its expression during embryogenesis is therefore informative of the initial events of eye development in Drosophila. We have analyzed how the initial expression domain of toy at cellular blastoderm is regulated. We show that the three maternal patterning systems active in the cephalic region (the anterior, terminal and dorsal-ventral systems) cooperate with zygotically activated gap genes to shape the initial expression domain of toy. Whereas Bicoid, Dorsal and Torso signaling synergistically act as activators, Hunchback, Knirps and Decapentaplegic act as repressors.     

广西青藓科分类学修订

通过对采自广西24个县(市)的1 147份青藓科植物标本的逐一鉴定及相关文献的查阅,确认有广西青藓科植物11属、44种,其中包括广西青藓科植物新记录属1属,即拟异叶藓属(Pseudokindbergia),新记录种7种,分别为匐枝青藓(Brachythecium procumbens)、阔叶尖喙藓(Oxyrrhynchium latifolium)、泛生尖喙藓(O. vagans)、拟异叶藓(Pseudokindbergia dumosa)、华东细喙藓(Rhynchostegiella sinensis)、长肋拟青藓(Sciurohypnum populeum)和弯叶拟青藓(S. reflexum)。该文提供了修订后的广西青藓科植物名录,并对其中的新记录属、种的主要形态学识别特征、生境和地理分布等进行了详细描述。     

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A–C (1–3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC₅₀'s 4.1 and 9.7 μg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 μg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC₅₀'s 2.0 and 5.8 μg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.2, 16.6 and 22.4 μg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 μg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).     

Apoptotic Regulation of Caspase Activity

Intracellular cysteine aspartate-specific proteases (caspases) play both signaling and effector roles in realizing the program of cell death. Caspases function as proteolytic cascades unique for each cell type and signal triggering apoptosis. All parts of the proteolytic cascades are duplicated and controlled by feedback signals. Amplification cycles between pairs of caspases (the third and the sixth, the ninth and the third, the twelfth and the sixth, and others) help multiply the initial apoptotic signal. The presence of physiological inhibitors of apoptosis that directly interact with caspases creates a multilevel regulatory network of apoptosis in cell. The caspase proteolytic cascades are also regulated by sphingolipid secondary messengers, among them ceramide, sphingosine, and their phosphates. Moreover, an association of the caspase signaling with ubiquitin-dependent proteolysis is shown in cells. In particular, the use of extracellular activators and inhibitors of caspases allows irreversible activation of apoptosis in tumor cells or the prevention of apoptosis in cortical neurons under neurodegenerative diseases.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Diversity and structure of shrew communities in montane forests of southeast Kenya

As a step towards setting conservation priorities for declining moist forests in southeast Kenya, we assessed for small mammal diversity and distribution. These habitats are under severe pressure due to increased demand an forests products and arable land, yet there is a dearth of information an impacts an biodiversity. Over an eight-month period, we used a combination of box and pitfall traps with drift fences to study 13 forest fragments in five geographic areas ranging between 3°28′−4°10′ S and 38°28′−39°2b′ E. We recorded 12 species including 10 soricids and two macroscelids in 31440 trap nights. Diversity estimates using rarefaction method indicate a species richness of 12, consistent with our collection. There were six unique species, each limited in distribution to one forest fragment. Our record of Crocidura cf. selina in Kyulu Hills is the first outside Mabira forest in Uganda where it is considered endemic and endangered. We also report the first record of C. fuscomurina in Kenya, white those of C. Luna and Suncus megalura are first in the southeast of the country. By providing new ranges to four species, our study is of significance to the biogeography and conservation of forest small mammals in the region.     

Selection and evaluation of the potential of choline-metabolizing microbial strains to reduce Fusarium head blight

Choline and betaine are found in wheat flower tissues and have been implicated in stimulating hyphal growth of the primary causal agent of Fusarium head blight (FHB), Gibberella zeae. Choline metabolizing strains (CMS) from wheat anthers may therefore be a useful source of antagonists of G. zeae. One-hundred twenty-three of 738 microbial strains that were recovered from wheat anthers collected from plants grown in Illinois and Ohio were CMS as determined by growth in a liquid medium containing choline as a sole carbon and nitrogen source and a colorimetric, choline oxidase-based assay of culture filtrate. Thirty-one out of 123 CMS reduced FHB disease severity by at least 25% in greenhouse tests on wheat and 17 reduced FHB severity by at least 50%. All five CMS selected for field testing in 2003 reduced disease severity compared to the untreated check at both field locations on moderately resistant cultivar Freedom. Freedom wheat treated with Pseudomonas sp. AS 64.4 had 63% and 46% less FHB severity than untreated wheat at the two sites. Three of five CMS reduced severity at both locations on susceptible cultivar Pioneer Brand 2545. Disease control was comparable to that obtained using the fungicide Folicur 3.6F. Selection of wheat anther colonists for ability to utilize choline as a sole carbon and nitrogen source has utility as a screening tool in the search for efficacious antagonists of G. zeae although choline utilization does not insure that an isolate will be an effective biocontrol agent against Fusarium head blight.