肌动蛋白存在于车蝗精母细胞核和染色体中

以兔抗肌动蛋白抗体为一抗,FITC偶联的羊抗兔IgG抗体为二抗进行间接免疫荧光实验,观察到车蝗（Oedaleus asiaticus）精母细胞核及减数分裂Ⅰ细线期、终变期、减数分裂Ⅱ中期染色体上均发出明亮的黄经发色荧光,说明其中含有肌动蛋白。本文结果证明肌动蛋白是车蝗减数分裂细胞核和染色体的组成成分。     

F—肌动蛋白是蒜根端分生组织细胞核和染色体的组成成分

以兔抗鸡肌动蛋白抗体为一抗、ＦＩＴＣ羊抗兔ＩｇＧ抗体为二抗进行间接免疫荧光标记实验,观察到蒜（ＡｌｉｕｍｓａｔｉｖｕｍＬ．）根端分生组织细胞核和染色体均发出明亮的黄绿色荧光,说明其中含有肌动蛋白。经ＴＲＩＴＣ鬼笔环肽标记后,完整的间期细胞、游离的间期细胞核、前期和中期染色体以及末期子细胞核均发出较强的红色荧光,而固定前用细胞松弛素Ｄ处理的根端分生组织细胞的荧光明显减弱或没有荧光,这些结果说明细胞核和染色体中存在着Ｆ肌动蛋白。抗肌动蛋白抗体和鬼笔环肽双标记实验结果指出,同一细胞核和染色体,在ＦＩＴＣ的激发光波长下发出代表总肌动蛋白的黄绿色的ＦＩＴＣ型荧光,在ＴＲＩＴＣ的激发光波长下则发出代表Ｆ肌动蛋白的红色的ＴＲＩＴＣ型荧光,两类荧光的分布是一致的。上述结果进一步证明Ｆ肌动蛋白是细胞核和染色体的组成成分,并说明Ｆ肌动蛋白可能是细胞核和染色体中肌动蛋白的主要存在方式。     

共聚焦荧光镜检术揭示大蒜鳞片细胞间期核中的F肌动蛋白网络

采用免疫荧光和荧光分子探针技术与共聚焦激光扫描显微镜观察相结合,对大蒜（Ａｌｌｉｕｍ ｓａｔｉｖｕｍ Ｌ．）鳞片细胞间期核中是否存在Ｆ肌动蛋白进行了研究。结果表明,以兔抗肌动蛋折抗体为一抗、ＦＴＴＧ－羊抗兔ＩｇＧ抗体为二抗进行免疫荧光标记实验,在荧光镜下观察到蒜瓣薄壁组织的细胞核及表皮细胞核均发出明亮的黄绿色荧光经共聚焦激光扫描显微镜进一步检查,整个细胞核呈黄绿色荧光,说明其中含有肌动蛋白。经ＴＲ     

肌动蛋白存在于蚕豆细胞核和染色体中

以兔抗肌动蛋白抗体为一抗,FTTC偶联的羊抗兔IgG抗体为二抗进行间接免疫荧光实验,观察到蚕豆(Vicia faba L.)根端分生组织中完整的细胞核和染色体均有明亮荧光。用抗肌动蛋白抗体和蛋白A-胶体金进行标记的免疫电镜实验结果表明,金颗粒分布在蚕豆细胞核中,集缩染色质和核仁中金颗粒较多。经DNaseI消化和2 mol/L NaCl处理得到去除DNA和组蛋白的细胞核和染色体。免疫荧光实验结果指出,去除DNA和组蛋白的细胞核和染色体与抗肌动蛋白抗体呈阳性反应。上述结果说明,肌动蛋白不仅存在于完整的蚕豆细胞核和染色体中,而且存在于去除DNA和组蛋白的蚕豆细胞核和染色体中。另外,用抗原肌球蛋白抗体所做的免疫荧光标记结果表明,原肌球蛋白也存在于蚕豆细胞核和染色体中。对高等植物细胞核和染色体以及核骨架和染色体骨架是否含有肌动蛋白等问题进行了讨论。     

肌动蛋白存在于金黄地鼠联会复合体中

以金黄地鼠精母细胞为材料,以抗肌动蛋白抗体为探针,应用免疫荧光和免疫胶体金技术有ＳＣ有无肌动蛋白的问题进行了研究。免疫荧光结果表明,经抗肌动蛋白抗体标记后,减数分裂粗线期标本中ＳＣ发出特异性荧光,说明肌动蛋白存在于ＳＣ中,免疫电镜结果表明：实验组ＳＣ的胶体金颗粒密度远高于对照组的金颗粒密度,说明ＳＣ含有肌动蛋白。观察到,常染色体ＳＣ和性染色体ＳＣ以及偶线期和粗线期ＳＣ中都含有肌动蛋白,肌动蛋白分布     

肌动蛋白是多头绒泡菌细胞核骨架和染色体骨架的组成成分

自多头绒泡菌(Physarum polycephalum Schw.)的原质团中分离细胞核和染色体,分别经DNaseⅠ消化和2 mol/L NaCl抽提后制备成细胞核骨架和染色体骨架。以抗肌动蛋白的抗体作一抗、FITC标记的羊抗兔IgG抗体作二抗进行的间接免疫荧光实验结果显示,细胞核骨架和染色体骨架都分别与抗体呈阳性反应。间接免疫斑点印迹实验结果进一步证实,细胞核骨架和染色体骨架的蛋白质成分中存在与肌动蛋白抗体呈阳性显色反应的抗原。以抗肌动蛋白的抗体作一抗、金颗粒标记的蛋白A作二抗的间接免疫电镜实验结果表明,在实验组间期细胞核的核仁、集缩染色质和核基质以及中期染色体上都有很多金颗粒分布。上述结果证明,肌动蛋白是多头绒泡菌细胞核和染色体及其骨架的组成成分。     

将大赖草种质转移给普通小麦的研究──Ⅲ．抗赤霉病异附加系选育

大赖草比抗病品种“苏麦３号”更抗小麦赤霉病。经离体和活体赤霉病抗性单花滴注鉴定和有丝分裂中期及减数分裂中期Ⅰ的Ｃ－分带分析,选育出添加了１对第２染色体的抗赤霉病异附加系,其４４条染色体在ＭＩ配成０．１２—０．４０ⅠＩ＋２１．７０—２１．９３Ⅱ＋０．０１—０．０４Ⅳ。经Ｃ－分带和生物素标记的染色体组ＤＮＡ作探针的分子原位杂交分析证实添加的１对外源染色体在ＭＩ配成二价体,在细胞学上已基本稳定。     

荧光原位杂交分析小麦-簇毛麦杂种减数分裂与染色体易位

利用基因组ＤＮＡ荧光原位杂交技术详细地研究了小麦－簇毛麦杂种染色体的减数分裂和配对行为,结果表明,在中期Ⅰ,小麦和簇毛麦染色体多呈两个单价体,在０．３％的ＰＭＣ中小麦与簇毛麦染色体发生配对;在后期Ⅰ时,单价体错分裂频率为３２．７％－３７．５％,另有０．７％的小麦－簇毛麦染色体重组易位出现;后期Ⅱ时,断列染色体的频率为２０．５％－２２．４％,还发现有０．８２％－１．７２％的自发易位染色体形成,此外,     

抗白粉病小麦-中间偃麦草二体异附加系与杀配子材料杂交后代的细胞遗传学研究

利用已选育的抗白粉病烟农15-中间偃麦草二体异附加系与农林26-离果山羊草3C染色体附加系杂交．对其F1、F2、F3的细胞遗传学进行研究．结果表明：F1花粉母细胞减数分裂中期Ⅰ染色体构型紊乱,在39．48％的细胞中发现染色体断片、单价体,后期Ⅰ、后期Ⅱ出现落后染色体、染色体桥．四分体期微核出现频率达48．65％,说明杀配子染色体可有效诱导染色体发生断裂等结构变异;F2代在细胞学方面仍不稳定,表现为染色体数目发生变异,花粉母细胞减数分裂染色体构型紊乱。多价体、落后染色体、染色体桥及微核的普遍出现．说明染色体问可能发生断裂、重接、交换或易位等现象,F2代白粉病抗性也出现分离;F3代虽然染色体数日和白粉病抗性仍在分离,但花粉母细胞减数分裂中期Ⅰ染色体构型较F2稳定,相对紊乱系数下降．从F3代鉴定出了染色体数目为42、构型稳定且对白粉病表现免疫的单株。     

肌动蛋白存在于金黄地鼠(Mesocricetus auratus)联会复合体中

以金黄地鼠精母细胞为材料,以抗肌动蛋白抗体为探针,应用免疫荧光和免疫胶体金技术对ＳＣ有无肌动蛋白的问题进行了研究。免疫荧光结果表明：经抗肌动蛋白抗体标记后,减数分裂粗线期标本中ＳＣ发出特异性荧光,说明肌动蛋白存在于ＳＣ中。免疫电镜结果表明：实验组ＳＣ的胶体金颗粒密度远高于对照组的金颗粒密度,说明ＳＣ含有肌动蛋白。观察到,常染色体ＳＣ和性染色体ＳＣ以及偶线期和粗线期ＳＣ中都含有肌动蛋白,肌动蛋白分布于ＳＣ的端部和侧生组分上,代表肌动蛋白的胶体金颗粒在ＳＣ上往往成簇存在。对ＳＣ含有肌动蛋白的意义进行了讨论。     

F-actin is a Nuclear and Chromosomal Component of the Meristematic Cells of Allium sativum

It is known that actin functionates in the form of F-actin. However, the presence of Factin in eukaryotic nuclei and chromosomes has not been well established. The authors labeled meristematic cells of Allium sativum L. with rabbit anti-chicken actin antibody and FITC-conjugated goat anti-rabbit IgG antibody and observed with fluorescence microscopy. Both the nuclei and chromosomes showed prominent yellow-green fluorescence, indicating the presence of actin in them. Fluorescence examination with TR1TC-conjugated phalloidin demonstrated prominent red fluorescence in the intact interphase cells, cytoplasm-free interphase nuclei, prophase and metaphase chromosomes as well as the daughter nuclei at telophase indicating the presence of F-actin; but the fluorescence was absent or very weak in the cells exposed to cytochalasin D before fixation. When double labeling of the anti-actin antibody and phalloidin was applied, the same nuclei and chromosomes were found to emanate yellow-green fluorescence representing actin at the excitation wavelength of F1TC, and red fluorescence representing F-actin at the excitation wavelength of TRITC, respectively. The FITC fluorescence and TRITC fluorescence shared the same distribution among the nuclei and chromosomes. These results indicate that F-actin is a component of the nuclei and chromosomes of the meristematic cells of A. sativum. It also suggests that F-actin may be the major existing form of actin in them.     

Meiotic restitution in wheat-barley hybrids

Meiotic restitution occurs in pollen mother cells (PMCs) of reciprocal F₁ hybrids between wheat and barley. In occasional PMCs, all or most of the 28 chromosomes assemble at the equatorial plate at metaphase I, but instead of undergoing anaphase I separation they reform into a mass of chromatin to form a restitution nucleus. Some of these restituted nuclei undergo a regular second division and dyads are produced among other non-restituted cells which have reached the tetrad stage of division. Other restituted nuclei fail to undergo a second division and then the PMCs appear as monads among neighbouring tetrads. Both the monads and dyads are expected to produce microsporocytes with the diploid complement of chromosomes. Chromosomes which fail to become included in the restituted nucleus form separate micronuclei and, depending on whether they undergo a regular second division or not, the PMCs containing them eventually appear as tetrads, triads or dyads. These partially restituted nuclei are expected to produce unreduced gametes, deficient for one or more chromosomes. It is postulated from these observations that restitution in wheatbarley F₁ hybrids depends on a high frequency of univalent accumulation at the equatorial plate at metaphase I and the subsequent failure of the chromosomes to undergo anaphase I separation.     

S基因在甘蓝EDFs上的高分辨率荧光原位杂交定位

植物细胞壁及细胞质的存在和植物染色体所具有的高浓缩特性,限制高效率原位杂交定位在植物细胞内的进行。针对小型染色体芸薹属植物采用常规方法DNA制备纤维的效果不佳的特点,新建制备方法：利用减数分裂前期的染色体为材料,在硅化的玻片上先后通过蛋白酶解和乙醇：乙酸（3：1）的适当处理,采用移动界而法制备EDFs。制备的EDFs比未经伸长处理的染色体在经向和横向方面分别取得较高程度的伸长与膨胀,长度可达到89-257μm,比相应地中期染色体增长30107倍,分辨率可达42．853．0kb。利用SRK和SCR两种探针同时在甘蓝粗线期染色体和EDFs上进行了原位杂交,首次鉴定了S基因座在其单倍体基因组中单拷贝性。在杂交信号检测中尽管未经过信号放大,但仍然可以观察到清晰的绿色信号;经荧光显微镜观察,在单一的EDF上发现两个相距1μm的SCR和SRK的信号点,由此得出局部分辨率为4kb的最高伸长度。     

A mutation in the spindle checkpoint arresting meiosis II in Brachiaria ruziziensis.

Cytological characterization of BRA005568 accession of Brachiaria ruziziensis (2n = 2x = 18) showed a totally unexpected high frequency of abnormal meiotic products, from triads to hexads, and also tetrads with micro nuclei or microcytes. Meiosis I had a low frequency of abnormalities, mainly related to the chiasma terminalization process. In meiosis II, however, frequency of abnormalities increased exceptionally. Early prophase II was normal with the chromosome set enclosed by the nuclear envelope. However, in late prophase II, owing to the breakdown of the nuclear envelope, the chromosomes were scattered in the cytoplasm. Some chromosomes did not reach the metaphase II plate and remained scattered. The behavior of sister cells was inconsistent. While in one cell the chromosomes were totally aligned at the metaphase II plate, in the other they could be found completely scattered, leading to an asynchronous cell division. Cells with scattered chromosomes were unable to progress in meiosis. Thus, anaphase II failed to occur and sister chromatids were not released. Cells with non-aligned chromosomes in the metaphase II plate did not receive the "go ahead" sign to initiate anaphase II. Consequently, the scattered chromosomes produced telophase II nuclei of different sizes in situ. The asynchronous behavior led to the formation of a wide range of meiotic products. Results suggest that the present accession contains a mutation affecting the spindle checkpoint that arrests the second meiotic division.     

Cytoskeletal asymmetry in Zea mays subsidiary cell mother cells: a monopolar prophase microtubule half-spindle anchors the nucleus to its polar position

Double labeling of microtubules and actin filaments revealed that in prophase subsidiary mother cells of Zea mays a monopolar prophase microtubule "half-spindle" is formed, which lines the nuclear hemisphere distal to the inducing guard mother cell. The nuclear hemisphere proximal to the guard mother cell is lined by an F-actin cap, consisting of a cortical F-actin patch and actin filaments originating from it. The microtubules of the "half-spindle" decline from the nuclear surface and terminate to the preprophase microtubule band. After disintegration of the latter, a bipolar metaphase spindle is organized. The polar F-actin cap persists during mitosis and early cytokinesis, extending to the chromosomes and the subsidiary cell daughter nucleus. In oryzalin treated subsidiary mother cells the prophase nuclei move away from the polar site. Cytochalasin B and latrunculin-B block the polar migration of subsidiary mother cell nuclei, but do not affect those already settled to the polar position. The prophase nuclei of latrunculin-B treated subsidiary mother cells are globally surrounded by microtubules, while the division plane of latrunculin-B treated subsidiary mother cells is misaligned. The prophase nuclei of brick 1 mutant Zea mays subsidiary mother cells without F-actin patch are also globally surrounded by microtubules. The presented data show that the prophase microtubule "half-spindle"-preprophase band complex anchors the subsidiary mother cell nucleus to the polar cell site, while the polar F-actin cap stabilizes the one metaphase spindle pole proximal to the inducing guard mother cell.     

东乡野生稻与栽培稻正反交种间杂种F1的雄配子发生与发育

该文以东乡野生稻与栽培稻(美国光壳稻P1003)的正反交种间杂种F₁(正交为光壳稻P1003×东乡野生稻; 反交为东乡野生稻×光壳稻P1003)为试材, 研究其各个减数分裂时期的染色体行为特征、染色体交换重组及雄配子发育特点。结果表明: 正反交杂种F₁花粉母细胞细胞核减数分裂的同步性较高, 细胞质为连续型胞质分裂类型。在细胞核分裂的过程中, 核仁在前期I到中期I逐渐消失。染色体在前期I到中期I逐渐收缩, 变得更加清晰可见。在终变期和中期I, 90.54%以上的花粉母细胞能形成12个二价体(含少数棒状二价体和8字型二价体), 部分花粉母细胞(正交9.46%, 反交7.65%)出现少量的单价体、三价体和四价体。后期I观察到1.27%–1.35%的花粉母细胞含有1至数条落后染色体。最终有92.6%–94.8%的小孢子能发育成形态正常、染色能力强的成熟花粉粒。另外, 在正交杂种F₁的粗线期中存在2个核仁, 而反交杂种F₁及其双亲的粗线期只有1个核仁。这些研究结果可为作物品种改良、种质资源创新以及种间亲缘关系研究提供细胞学证据。     

Stage-specific damage to synaptonemal complexes and metaphase chromosomes induced by X rays in male mouse germ cells

Synaptonemal complexes reveal mutagen-induced effects in germ cell meiotic chromosomes. This study was aimed at characterizing relationships between damage to synaptonemal complexes and metaphase I chromosomes following radiation exposure at various stages of spermatogenesis. Male mice were irradiated with doses of 0, 2, or 4 Gy, and spermatocytes were harvested at times consistent with earlier exposures as spermatogonial stem cells, preleptotene cells (premeiotic DNA synthesis), or meiotic prophase cells. After stem-cell exposure, twice as many rearrangements were observed in synaptonemal complexes as in metaphase I chromosomes. Irradiation during premeiotic DNA synthesis resulted in dose-related increases in synaptonemal complex breakage and rearrangements (including novel forms) and in metaphase chromosomal aberrations. Following prophase exposure, various types and levels of damage to synaptonemal complexes and metaphase chromosomes were observed. Irradiation of zygotene cells led to high frequencies of chromosome multivalents in metaphase I without a correspondingly high level of damage in preceding prophase synaptonemal complexes. Thus irradiation of premeiotic and meiotic cells results in variable relationships between damage to synaptonemal complexes and metaphase chromosomes. Interpretations of these relationships are based upon what is known about both radiation clastogenesis and the structural/temporal relationships between synaptonemal complexes at prophase and chromosomes at metaphase I of meiosis.     

Apomeiotic pollen mother cell development in the apomictic <Emphasis Type="Italic">Boechera</Emphasis> species

Pollen mother cell (PMC) development in the apomictic Boechera species B. holboellii, B. gunnisoniana and B. divaricarpa were investigated by various cytological methods. In prophase I, in triploid species B. holboellii and B. gunnisoniana the individual chromosomes condensed into long strands within the nucleus. Then, in metaphase I, each PMC formed a restitutional nucleus thereby bypassing the rest of the first meiotic division. This is interpreted as representing apomeiosis. Subsequently, the restitution nuclei underwent a single cytokinesis as evidenced by the production of dyads. The cells within each dyad were separated by a callose wall. Most of the PMC in B. holboellii and B. gunnisoniana produced dyads, but a small proportion generated conspicuous tetrads. In contrast, diploid apomict B. divaricarpa produced only tetrads by simultaneous cytokinesis.     

Dynamics of the actin cytoskeleton,hyphal tip growth and the movement of the two nuclei in the dikaryon ofCoprinus cinereus

We first examined the changes in distribution of F-actin during conjugate division in the apical cells of the dikaryon ofCoprinus cinereus using indirect immunofluorescence microscopy, then followed hyphal tip growth and the movement of the two nuclei in the apical cells using differential interference contrast microscopy (DIC). In apical cells with interphase nuclei, F-actin occurred solely as peripheral plaques, which were distributed along the whole length of the cell and were more concentrated at the tips, where they formed caps. In the early prophase of conjugate division, F-actin was transiently concentrated, as diffused form and plaques, at hyphal regions where the two nuclei sit, and this was accompanied by transient disappearance of the actin cap at the hyphal tip in the majority of cells. The actin cap was also present at the tips of growing clamp cells from late prophase through metaphase and disintegrated during anaphase. In telophase, actin rings formed at the future septa. DIC revealed that, in early prophase, when the F-actin array occurs around the two nuclei and the actin cap is absent at hyphal tips, hyphae kept growing and the second nucleus accelerated its forward movement to catch up with the leading nucleus, which was still moving forward.