利用多基因序列探讨稻属药稻复合体二倍体物种的系统发育关系

稻属药稻复合体Oryza officinalis complex中有5个二倍体物种,涉及B、C和E3个染色体组,分布在亚洲、非洲和大洋洲。其中,O.australiensis是稻属中惟一含E染色体组的物种;O.punctata则是惟一含B染色体组的物种。虽然O.officinalis、O.rhizomatis和O.eichingeri都含C染色体组,但由于它们间断分布在亚洲和非洲,可能在稻属异源多倍体成种中发挥了不同作用。染色体组B、C和E之间,以及上述二倍体物种之间的系统发育关系及其在稻属多倍体物种形成     

利用叶绿体基因探讨稻属BBCC基因组物种的系统起源

基于9个叶绿体基因片段(atpA、atpB、matK、petA、psaA、psbA、psbB、psbC和rbcL), 深入探讨了稻属(Oryza)3个BBCC基因组异源四倍体和5个与之相关的BB或CC基因组二倍体物种间的谱系关系。进一步的系统发育分析表明: 3个具有相同BBCC基因组的四倍体物种并非同一次物种形成事件的产物, 而是在不同的分布区经历了至少3次分别的物种起源。其中, 四倍体Oryza punctata的母本可能来自同样分布在非洲并具有CC基因组的二倍体物种O. eichingeri; 而四倍体O. malampuzhaensis和O. minuta的母本则可能来自亚洲已经灭绝的具有BB基因组的不同二倍体。研究结果不但为追溯稻属异源四倍体的复杂网状进化提供了重要的分子证据, 而且拓展了我们对有花植物复杂物种形成的深入理解。     

稻属叶表皮结构特征及其系统学意义

本文对稻属Oryza L. 23种植物叶片表皮的结构特征进行了观察和研究,结果表明:叶表皮的某 些性状,如在叶片脉带之间长细胞中乳突的大小和分布以及叶表皮气孔器上小乳突的数目和着生位置 在稻属的各种之间有着一定的变异规律,这在稻属各种的分类和其系统关系的研究中有一定的价值。 综合这些性状的变异特征,按照叶片下表皮脉间长细胞中乳突的大小和分布特征以及气孔器中小乳突 的数目和着生位置可将稻属这23个物种分为3组。第一组包括长颖野稻、马来野稻、疣粒野稻和颗粒 野稻,这些种的叶表皮脉间长细胞中没有大乳突和中乳突,仅偶见极稀疏分布的小乳突,气孔器中均无 小乳突。第二组包括短药野稻、二倍体和四倍体药用野稻、小粒野稻、紧穗野稻、斑点野稻、阔叶野稻、高 株野稻、大颖野稻、根茎野稻和澳洲野稻,这些种的叶表皮脉间长细胞中通常没有大、中乳突,但密布小 乳突,且大多数种的气孔器保卫细胞的近两端各有2个小乳突。第三组包括栽培稻、一年生普通野稻、 多年生普通野稻、长雄蕊野稻、展颖野稻、南方野稻、矮舌野稻、非洲栽培稻和希来特野稻,这些种的叶 表皮脉间的长细胞中常有大乳突、中乳突和小乳突,而气孔器保卫细胞的近两端各有2个明显的小乳 突,并同时常在气孔器副卫细胞的近内缘还有2～4个小乳突。     

盾叶薯蓣四倍体与二倍体叶表皮及气孔器显微结构的比较

对盾叶薯蓣四倍体和二倍体阴叶和阳叶表皮及气孔器的显微形态结构进行了比较。结果显示:叶片表皮细胞及气孔器的形态结构因染色体倍性及光照的不同而存在明显差异。表皮细胞有规则多边形与不规则细胞壁内褶2种类型;气孔器为典型的双子叶植物无规则型气孔器,仅分布在下表皮。四倍体表皮细胞密度、气孔器密度及气孔指数平均值分别为476.28±6.87个.mm-2、78.22±3.1个.mm-2、14.11,较二倍体的分别小4.60%、17.95%和11.98%。前者气孔器长、宽及保卫细胞宽度平均值分别为32.78±2.09μm、26.07±1.55μm、9.63±1.14μm,较后者的分别大10.73%、3.90%和18.01%,差异极显著。前者阴叶的较其阳叶的分别大5.77%、6.00%、8.72%;后者的则分别大1.72%、1.74%、2.41%。前者叶片保卫细胞中的叶绿体数目为23.93±3.19个,较后者的多74.00%。表皮细胞及气孔器密度、气孔指数,气孔器大小,保卫细胞叶绿体数目、尤其是保卫细胞宽度,可作为倍性鉴定的参考依据。四倍体高产有其良好的叶片结构基础。     

不同倍性盾叶薯蓣(Dioscorea zingiberensis)叶表皮形态的比较

通过对二倍体(2x=20)、三倍体(3x=30)、四倍体(4x=40)盾叶薯蓣植株叶片上下表皮细胞密度、细胞形状系数,气孔器大小、气孔指数、气孔密度,以及气孔器保卫细胞叶绿体数与倍性相关性的比较,探讨多倍体在盾叶薯蓣倍性育种上的前景。结果表明:随着倍性增加,盾叶薯蓣表皮细胞密度、气孔器面积、长、宽、以及保卫细胞宽、保卫细胞叶绿体数均明显增大。气孔器面积和保卫细胞宽与倍性成正比,且差异显著,可以作为倍性鉴定的手段之一。     

伯乐树不同发育阶段叶片表面附属结构特征

利用石蜡切片及电子显微镜扫描技术,对伯乐树（Bretschneidera sinensis）不同发育阶段的叶表面表皮毛、角质层、乳突和气孔器4种附属结构进行了观察。结果显示：伯乐树叶的上、下表面和叶脉处分布着单细胞或多细胞的单列表皮毛,表皮毛的密度随着叶片的生长发育逐渐稀疏;叶片上表面覆盖着条纹状的角质层;叶片的下表面有鲜花状乳突,密度随叶片的生长逐渐稀疏;气孔仅见于下表面,气孔器类型为无规则型。伯乐树和叠珠树叶片具有相似的乳突结构,结合形态学、解剖学及分子证据,在一定程度上显示了伯乐树与叠珠树科可能存在较密切的关系;叶表面附属结构的特点反映了伯乐树对环境的长期适应。     

黄独(Dioscorea bulbifera L.)不同居群叶表皮微形态特征的比较观察

应用扫描电子显微镜(SEM)对15个黄独(Dioscorea bulbifera L.)居群(11个野生居群及4个栽培居群)植株的叶表皮微形态特征(包括气孔器、表皮毛和气孔周围表皮细胞的特征)进行了观察和测量,并据此编制了15个黄独居群的检索表.观察结果表明:15个黄独居群植株叶片在气孔器外拱盖内缘类型,气孔器旋转方向,气孔长轴长度及密度和深度,叶片表皮毛的有无及类型,叶肉腺毛的长、短轴长度及密度,气孔周围表皮细胞垂周壁和平周壁的形态以及平周壁表面颗粒形状等特征上均有明显差异.气孔器外拱盖内缘有光滑和浅波状2种类型;气孔器的旋转方向分为不定向旋转、左旋和右旋3种方式;气孔长轴长度和密度的变化幅度分别为18.59～31.93 μm和86～356 mm-2.叶片表皮毛均仅存在于下表皮,可分为乳突和多细胞头单细胞柄腺毛2种类型,乳突主要分布于主脉,腺毛主要分布于二级脉和叶肉;叶肉腺毛的长、短轴长度的变化幅度分别为25.00～55.00和24.86～44.29μm,大部分居群腺毛密度的变化幅度为6～29 mm-2.叶片气孔周围表皮细胞垂周壁的形状有平直、平直隆起、平直脊状隆起、弯曲、弯曲脊状隆起和弯曲拱状隆起6种类型;表皮细胞平周壁的表面纹饰有具瘤条纹和光滑条纹2种形态,其扩散方式也有2种形式:一种为不环绕气孔且四方扩散,另一种为环绕气孔2～3周后扩散但扩散方向不定;平周壁上的颗粒形状有簇晶状、屑状、密集粉状、粉状、粒状和片状6种类型.比较分析结果显示:黄独不同居群叶表皮微形态特征的多态性较为丰富,地理分布相近的居群微形态特征的相似性较高,这些特征与黄独的各种下分类群相对应.     

安徽产两种山罗花属植物及其居群叶的微形态比较

利用离析法、扫描电镜和石蜡切片法对安徽产2种3居群山罗花属植物的叶进行了微形态比较研究,结果表明：该属植物叶表皮细胞形状为不规则形,垂周壁呈波状、深波状至重波状;表皮细胞内含叶绿体;角质层具条状纹饰;表皮上有表皮毛和腺毛分布,扫描电镜下表皮毛具瘤状突起的纹饰;栅栏组织只有1层,排列比较疏松,海绵组织有发达的胞间隙;气孔器多为无规则型,极少数仅有一个副卫细胞,仅分布于下表皮,扫描电镜下气孔外拱盖内缘近光滑或浅波状。2种植物在垂周壁式样、表皮毛密度、气孔器长宽比、栅栏组织和海绵组织的厚度比以及中脉的结构特征等具有明显的差异,而山罗花3居群间的差异不明显。     

酢浆草属5种植物的微形态特征观察

利用光镜和扫描电镜观察了酢浆草属(Oxalis L.)5种植物的叶、花、花粉和部分种子的微形态结构。5种植物叶片上均具有平列型气孔器,外围3~4个不规则表皮细胞;酢浆草(O.corniculata L.)、铜锤草(O.corymbosa DC.)及白花酢浆草(O.acetosella L.)叶片两面均有气孔器,下表皮犹密;紫叶酢浆草(O.triangularis A.St.-Hil.)和山酢浆草(O.griffithii Edgew.et Hook.f.)的气孔器只分布于叶片下表皮。不同种间及长、短雄蕊上的花粉粒大小各异,花粉多呈近球形(酢浆草、白花酢浆草)、长球形(紫叶酢浆草、山酢浆草)或超长球形(铜锤草),极面观为三裂圆形,赤道面大多具3沟,少数4沟,表面具有不规则的穴状或粗网状纹饰,网眼内无或有乳突状突起(铜锤草、紫叶酢浆草)。酢浆草种子较小,表皮纹饰为比较规则的不等边六角形网眼,网眼中间具棱柱状突起,上有钩状附属物;山酢浆草种子较大,表皮粗糙程度低于酢浆草。     

新疆委陵菜属不同花柱组植物叶表皮微形态结构的研究

利用光学显微镜和扫描电子显微镜,观察了新疆委陵菜属5组不同花柱组10种4变种植物叶表皮的微形态特征,测量统计叶表皮毛的类型、表皮细胞的形状及大小、气孔器的分布及类型、气孔的形状、大小、密度及指数、气孔外拱盖形态及其纹饰等指标。结果显示:新疆委陵菜属10种4变种植物叶的下表皮均有气孔器的分布,形状为长椭圆形、椭圆形、宽椭圆形和近圆形;气孔器的类型多为无规则四细胞型、无规则型、围绕型和辐射型;表皮毛的类型为针状毛、带状柔毛和腺毛;表皮细胞的形状分为不规则形和多边形2种类型。研究表明,新疆委陵菜属植物表皮毛特征、叶片表皮细胞的形状、垂周壁式样、气孔器的形状类型、气孔密度指数及外围蜡质纹饰等存在差异,对属以下等级的划分有重要价值,可作为物种分类及鉴别的依据,同时也为本属一些分类群间的系统关系的探讨提供佐证。     

中国红豆属植物的叶表皮形态学

用光学显微镜和扫描电子显微镜观察了红豆属(Ormosia)35种的叶表皮形态,这些植物的叶上下表皮细胞为不规则形或多边形,垂周壁有平直、弓形、浅波状或深波状,表皮细胞形状和垂周壁在种间有一些差异。气孔仅存在于下表皮,形状为椭圆形或卵形,以平列型为主;此外还有其他类型的气孔,如长脐红豆、海南红豆等的气孔为不规则形、不等型;少数种类如亮毛红豆、茸荚红豆等的气孔不明显。气孔外拱盖光滑,呈浅波状、波状或不明显,气孔内拱盖光滑、近光滑、浅波状或不明显;蜡被近光滑、颗粒状、鳞片状、条纹状或结网状;多数种具毛被。叶表皮与气孔器特征可作为区分种、变种或亚种的依据。叶表皮微观形态特征支持红豆属成为一个自然类群。     

木犀属植物叶柄的比较解剖学研究

对木犀属(Osmanthus)26种植物叶柄的解剖结构进行了研究.结果表明,木犀属植物叶柄的解剖特征存在比较丰富的变异,叶柄横切面形状有3种类型(U型、V型、Y型),周缘波状、浅波状或近平滑;表皮毛有或无;维管束一般为1大2小,维管束轮廓在种问变异丰富,维管束类型有周韧、近周韧、外韧3种;小叶月桂、牛矢果、厚边木犀、美洲木犀叶柄中央具髓腔,部分种叶柄有硬化细胞或石细胞存在.木犀属植物叶柄的解剖结构特征比较稳定,可作为该属的分种特征.     

The Mouthparts in Some North Atlantic Species of the Genus Orchomene Boeck (Crustacea, Amphipoda)

The mouthparts of five North Atlantic species of the genus Orchomene have been studied in detail. The species are: O. serrata (Boeck, 1861), O. amblyops G. O. Sars, 1890, O. crispata (Goes, 1866). O. humilis (A. Costa, 1853) and O. pectinate. G. O. Sars, 1882. The structure of the mandibular molar has been studied with the aid of the scanning electron microscope. Some features of the mouthparts, common to the species examined, are interpreted as generic criteria which should justify retaining the genus Orchomene Boeck, 1870, separated from the closely related genera OrchomeneUa G. O. Sars, 1890, and Orchomenopsis G. O. Sars. 1891.     

The effect of ultraviolet radiation on ultrastructure and photosynthesis in the red macroalgae Palmaria palmata and Odonthalia dentata from Arctic waters

In radiation exposure experiments, the effects of mild artificial UV conditions (4.7 W m(-2) UV-A and 0.20 W m(-2) UV-B) plus PAR (25 - 30 micromol photons m(-2) s(-1)) on photosynthesis and ultrastructure of two red algal species from the Arctic have been investigated. While Palmaria palmata was collected from the upper sublittoral of the Kongsfjord (Spitsbergen, Norway), Odonthalia dentata represents a typical deepwater species at this high latitude. After 6 h and 24 h exposure to UV, chlorophyll fluorescence of photosystem II (PS II efficiency, F(v)/F(m)) was determined as an indicator for photosynthetic performance, and the relative electron transport rates in response to increasing photon fluence rates were recorded. In parallel, tissue samples were prepared for the transmission electron microscope (TEM). The presented data clearly demonstrate a significant influence of experimental UV on photosynthetic performance. Photochemical efficiency of PS II of both red algal species decreased to about one third of the initial value under UV. While the PI (photosynthesis-irradiance) curve parameter alpha (positive slope at limiting photon fluence rates) strongly decreased in both plants, the I(k) values (initial value of light-saturated photosynthetic rate) increased 3 - 5-fold. Palmaria palmata does not appear to become photoinhibited under these conditions, but O. dentata showed strong photoinhibition. The TEM results demonstrated that the photosynthetic apparatus was severely influenced by UV in both species, because thylakoid membranes appeared wrinkled, lumen dilatations occurred, and the outer membranes were altered. Moreover, mitochondria were damaged, and numerous plasma vesicles were observed. In conclusion, both red algal species are negatively affected by UV on the physiological and ultrastructural level. However, the differences in photoinhibitory responses correlate well with the vertical depth zonation of P. palmata and O. dentata in the Arctic Kongsfjord.     

拉合尔钝缘蜱不同龄期若蜱超微形态

【目的】本研究旨在阐明新疆地区优势种拉合尔钝缘蜱Ornithodoros lahorensis不同龄期若蜱超微形态及其发育特征，为软蜱的形态特征研究及龄期划分提供形态学依据。【方法】在实验室条件下培养获得拉合尔钝缘蜱1-5龄若蜱虫体，分别通过体视显微镜与扫描电子显微镜对拉合尔钝缘蜱不同龄期若蜱形态特征进行详细观察。【结果】在体视显微镜下，1-5龄若蜱虫体均呈椭圆形，前端稍尖后端钝圆，体表呈淡黄色或黄褐色，有4对足。在扫描电子显微镜下，1-5龄若蜱具有如下相同特征：表皮均呈褶皱样；有瘤突；哈氏器呈横裂样；口下板呈矛形；气门呈半圆形；肛门呈圆形，由叶状肛瓣构成，无肛后横沟。1-5龄若蜱间的不同特征为：1龄若蜱刚毛长且粗，无瘤突，口下板顶端凹陷且齿式为2|2，无气门板；2龄若蜱瘤突不明显，口下板顶端有小凹陷且齿式为3|3，有气门板；3龄若蜱瘤突明显；4龄若蜱肛瓣毛为6对；5龄若蜱肛瓣毛为7对。【结论】拉合尔钝缘蜱1-5龄若蜱在体视显微镜下观察的形态结构基本相似；在扫描电子显微镜下观察的刚毛、瘤突、口下板、齿式、气门、气门板、肛瓣毛、肛前沟和肛中沟等形态特征可作为拉合尔钝缘蜱1-5龄若蜱的鉴定特征。本研究首次详细描述了拉合尔钝缘蜱各龄期若蜱形态结构，为软蜱龄期划分及生活史研究提供依据。     

Ultraviolet-B- and ozone-induced biochemical changes in antioxidant enzymes of Arabidopsis thaliana.

Earlier studies with Arabidopsis thaliana exposed to ultraviolet B (UV-B) and ozone (O3) have indicated the differential responses of superoxide dismutase and glutathione reductase. In this study, we have investigated whether A. thaliana genotype Landsberg erecta and its flavonoid-deficient mutant transparent testa (tt5) is capable of metabolizing UV-B- and O3-induced activated oxygen species by invoking similar antioxidant enzymes. UV-B exposure preferentially enhanced guaiacol-peroxidases, ascorbate peroxidase, and peroxidases specific to coniferyl alcohol and modified the substrate affinity of ascorbate peroxidase. O3 exposure enhanced superoxide dismutase, peroxidases, glutathione reductase, and ascorbate peroxidase to a similar degree and modified the substrate affinity of both glutathione reductase and ascorbate peroxidase. Both UV-B and O3 exposure enhanced similar Cu,Zn-superoxide dismutase isoforms. New isoforms of peroxidases and ascorbate peroxidase were synthesized in tt5 plants irradiated with UV-B. UV-B radiation, in contrast to O3, enhanced the activated oxygen species by increasing membrane-localized NADPH-oxidase activity and decreasing catalase activities. These results collectively suggest that (a) UV-B exposure preferentially induces peroxidase-related enzymes, whereas O3 exposure invokes the enzymes of superoxide dismutase/ascorbate-glutathione cycle, and (b) in contrast to O3, UV-B exposure generated activated oxygen species by increasing NADPH-oxidase activity.     

头足类腕上吸盘和内壳扫描电镜观察

本文采用扫描电子显微镜对7种头足类腕上的吸盘及乌贼的内壳进行观察。结果表明,蛸科（Octopodidae）的短蛸（Octopus ocellatus）、真蛸（O. vulgaris）和长蛸（O. variabilis）腕的吸盘均无齿,乌贼科（Sepiidae）的日本无针乌贼（Sepia japonica）和金乌贼（S.esculenta）的腕和触腕吸盘上的角质环均有齿,且齿的形状不一样;虎斑乌贼（S. pharoanis）触腕的吸盘角质环光滑无齿,枪乌贼科(Loliginidae)的中国枪乌贼（Uroteuthis chinensis）腕上吸盘的角质环无齿。对３种乌贼的内壳的横切面进行扫描电镜观察,乌贼的内壳的背表面和腹表面的结构均是由文石和铺在上面的球型颗粒构成,但文石的形状和小球的排列存在种间差异,这些差异可以作为头足类的分类辅助特征。     

槭树科花粉形态及其系统学意义

报道了槭树科(Aceraceae)槭属21组33种和金钱槭属2种植物的花粉形态。本科花粉近球形至长球形,极面观为三裂圆形。从花粉萌发孔类型看,金钱槭属Dipteronia具三孔沟,槭属（Acer)除4组具三孔沟外,其余均为三沟。从花粉外壁纹饰看,金钱槭属2个种和槭属的大多数种为条纹状,罕为细条纹－拟网状和皱波状。通过花粉形态分析,并结合其它方向的证据,我们认为：（1）Sect.Palmata,Sect.Spicata和Sect.Microcarpa可能是槭属中与金钱槭属关系最密切的类群;（2）A.distalum和A.nipponicum代表了近缘的两个单种组;（3）A.pseudoplatanus不同于Sect.Acer的其它4个种而与A.saccharum可能存在更为密切的关系;（4）Sect.Carpinifolia(细条纹－拟网状外壁纹饰）和Sect.Negundo(皱波状外壁纹饰）则可能代表了槭属中最特化的类群;（5）按槭树科花粉三孔沟到三沟的演化规律,Dipteronia较Acer原始。     

A new species of Osedax (Annelida: Siboglinidae) associated with whale carcasses off Kyushu, Japan

A new whale-bone-eating polychaete species of the genus Osedax was found on sperm whale carcasses submerged off Cape Nomamisaki, Kyushu, Japan, at a depth of approximately 200 m. The new species, Osedax japonicus, is the fourth known species of the genus Osedax and the first species from the western Pacific. Female O. japonicus specimens (1) form dense clusters on whale carcasses; (2) have a body composed of crown, trunk, and root structure; (3) lack a digestive tract; and (4) have bacterium-like particles in the tissue of the root structure. Osedax japonicus shares all these characteristics with O. rubiplumus and O. frankpressi, and items (1) to (3) with O. mucofloris. Osedax japonicus is easily distinguished from the other three known species by oviduct morphology, body length, and palp coloration in females. No males of O. japonicus have yet been found.     

The influence of spin-labeled fluorene compounds on the assembly and toxicity of the aβ peptide

Background

The deposition and oligomerization of amyloid β (Aβ) peptide plays a key role in the pathogenesis of Alzheimer''s disease (AD). Aβ peptide arises from cleavage of the membrane-associated domain of the amyloid precursor protein (APP) by β and γ secretases. Several lines of evidence point to the soluble Aβ oligomer (AβO) as the primary neurotoxic species in the etiology of AD. Recently, we have demonstrated that a class of fluorene molecules specifically disrupts the AβO species.

Methodology/Principal Findings

To achieve a better understanding of the mechanism of action of this disruptive ability, we extend the application of electron paramagnetic resonance (EPR) spectroscopy of site-directed spin labels in the Aβ peptide to investigate the binding and influence of fluorene compounds on AβO structure and dynamics. In addition, we have synthesized a spin-labeled fluorene (SLF) containing a pyrroline nitroxide group that provides both increased cell protection against AβO toxicity and a route to directly observe the binding of the fluorene to the AβO assembly. We also evaluate the ability of fluorenes to target multiple pathological processes involved in the neurodegenerative cascade, such as their ability to block AβO toxicity, scavenge free radicals and diminish the formation of intracellular AβO species.

Conclusions

Fluorene modified with pyrroline nitroxide may be especially useful in counteracting Aβ peptide toxicity, because they posses both antioxidant properties and the ability to disrupt AβO species.