葡萄胚珠,胚乳及胚的发育

本文研究了“早玫瑰”和“新玫瑰”葡萄胚珠、胚乳和胚的发育。结果表明:花后3天胚珠即开始迅速生长,其生长的最终大小依品种成熟期的不同而各异。胚乳游离核在花后33天成为细胞状态。受精后16—21天,合子才开始第一次分裂。当胚乳充满珠心组织时,胚开始迅速发育并一直持续到果实成熟.胚的发育与果实的发育无明显竞争关系。     

中棉×戴维逊氏棉胚胎发育的研究

以棉花栽培种中棉作母本,野生种戴维逊氏棉作父本进行杂交试验,并用中棉自交作对照,比较研究了杂交情况下花粉粒的萌发、花粉管的生长、受精作用及胚和胚乳的发育过程,得到以下结果:(1)中棉×戴维逊氏棉花粉粒的萌发及花粉管在异己花柱中的生长基本正常,有花粉管胚珠的频率约20％,为中棉自交的1/4左右;(2)在杂交情况下,有花粉管进入的胚珠基本上能实现受精;(3)杂种胚乳在授粉后7天发育异常,11天开始解体,16天才有部分胚珠的胚乳开始形成细胞壁;(4)杂种胚不分化或畸形分化,在授粉后11—22天坏死。     

高温与香烟联合对大鼠早期胚胎致畸作用的研究

为了探讨高温与香烟联合对胚胎的毒性和致畸作用,用高温（４０、４１、４２、４３℃）及香烟烟不溶４物联合处理怀孕的大鼠。结果表明,高温与香烟联合可加强胚胎的致畸作用,并与温度、香烟浓度和高温持续时间明显相关,当持续３分钟的高温与香烟联合,胚胎致畸率达７０％以上,与单独高温组、单独给烟组有明显差异（Ｐ〉０．０１）,并具有协同效应。结果提示,持续高温与香烟联合有明显的胚胎毒性和致畸作用。     

落葵的花粉粒和胚囊的形成与发育

落葵(Basella rubra L.)小孢子的发育为同时型,四分体呈四面体排列。在花粉母细胞减数分裂过程中,可清楚地看到胼胝壁的消长变化。三胞花粉,具散沟和网状纹饰。腺质绒毡层。 胚囊的发育为蓼型。反足细胞早期退化。内珠被突出形成珠被喙,同时,在其珠孔区域,有由内珠被的内表皮细胞所发育而来的类似盖状结构。 本文还注意到同一花中以及相邻花朵之间,花粉粒与胚囊发育进程的相关。花粉粒的发育略早于胚囊的发育,但以后由于胚囊母细胞形成胚囊的进程较为迅速,以致花粉粒与胚囊能够同时成熟。     

Interaction of FIE,a Polycomb protein,with pRb: a possible mechanism regulating endosperm development

Inactivation of the Arabidopsis protein FERTILIZATION INDEPENDENT ENDOSPERM (FIE) induces division of the central cell of the embryo sac, leading to endosperm development in the absence of fertilization. The mechanism whereby FIE regulates this process is unknown. We postulated that activation of central cell division in fie mutant plants might involve the retinoblastoma protein (pRb), a cell cycle regulatory element. Pull-down and surface plasmon resonance assays demonstrated that FIE interacts in-vitro with the pRb homologues from Arabidopsis (AtRb), maize (ZmRb) and human (HuRb). The interaction of FIE with ZmRB and HuRb in the yeast two-hybrid system supports the possibility that a FIE-pRb interaction may occur also in planta. Mutational analysis showed that this interaction does not occur via the LxCxE motif of the FIE protein nor via the pocket B domain of pRb. These results suggest that FIE may inhibit premature division of the central cell of the embryo sac, at least partly, through interaction with pRb, and suppression of pRb-regulated genes.Electronic Supplementary Material Supplementary material is available in the online version of this article at Communicated by R. G. Herrmann     

Confocal Microscopic Observations on Microtubular Cytoskeleton Changes During Megasporogenesis and Megagametogenesis in Phaius tankervilliae (Aiton) Bl.

In nun orchid (Phaius tankervilliae (Alton) B1. ) embryo sac development follows the monosporic pattern. Changes in the pattern of organization of the microtubular cytoskeleton during megasporogenesis and megagametogenesis in this orchid were studied using the immunofluorescence technique and eonfocal microscopy. At the initial stage of development the microtubules in the arehesporium were randomly oriented into a network. Later the archesporial cell elongated to form the megasporocyte. The cytoskeleton in the elongated megasporoeyte was radially organized in which microtubules extending from the nuclear envelope to the peripheral region of the cell. The megasporoeyte then underwent meiosis 1 to form a dyad. The dyad cell at the chalazal end was larger than the cell at the micropylar end. Microtubules in the dyad cell were radially oriented. The dyad underwent meiosis to give rise to a linear array of four megaspores (i. e. tetrad formation). The chalazal-far most megaspore survived and became the functional megaspore, which contained a set of randomly oriented microtubules. The microtubules in the other 3 megaspore disappeared as the cells degenerated. The functional megaspore then underwent mitotic division giveing rise to a 2 nucleate embryo sac. The nuclei of the 2-nucleate embryo sac were separated by a set of longitudinally oriented microtubules which ran parallel to the long axis of the embryo sac. Each nucleus in the embryo sac was surrounded by a set of perinuelear microtubules. The gnucleate embryo sac again underwent mitotic division to form a 4-nucleate embryo sac. The division of the two nuclei was synchronous. But the orientation of the division plan of the two spindles was different (i. e. the spindle microtubules at the chalazal end ran parallel with the long axis of the embryo sac and those at the mieropylar end ran at right angle to the axis of the embryo sac). The 4 nuclei of the 4-nucleate embryo sac were all tightly surrounded by randomly oriented microtubules. Later the paired nuclei at the micropylr end and at the chalazal end as well underwent mitotic division in seguence. At this time when the embryo sac had reached the 8-nucleate embryo sac stage. The pattern of organization of the microtubules was very complex. Initially the nuclei were surrounded by a set of randomly oriented microtubules, but after the two polar nuclei had moved to the central region of the embryo sac, three different organizational zones of microtubules appeared, viz: a randomly oriented set of microtubules surrounding each nucleus in the chalazal zone: a set (in the form of a basket) of cortical microtubules which surrounded the vacuoles and the two polar nuclei in the central zone and a loosely knitted network of microtubules surrounding the nucleus that later became the egg cell nucleus in the micropylar zone. The two nuclei that would become the nuclei of the synergids were surrounded by a set of more densely packed mierotubules. Towards far the most micropylar end some microtubules formed thick bundles. The site of appearance of these thick bundles coincided with the site of development of the filiform apparatus. The pattern of microtubule organization after cellularization (i. e. at the beginning of embryo sac maturation) did not change much. The author's results indicated that various patterns of microtubule organization observed in the developing embryo sac of nun orchid reflected the complexity and dynamism of the embryo sac.     

Isolation and propagation of yolk-sac-derived endothelial cells from a hypervascular transgenic mouse expressing a gain-of-functionFPS/FES proto-oncogene

Summary We report on the isolation and propagation of endothelial cells from the mouse embryonic yolk sac, the earliest site of blood vessel development, and on the advantages of a hypervascular transgenic mouse source of these cells. These transgenic mice express multiple copies of an activated allele of the humanfps/fes proto-oncogene and display hypervascularity progressing to multifocal hemangiomas. This phenotype suggested a role of thefps/fes proto-oncogene in vasculogenesis and angiogenesis and led us to investigate the growth characteristics of yolk-sac-derived endothelial cells from transgenicfps/fes embryos. We have established eight independent cell clones from a mixture of transgenic and control yolk sacs from Day 12 embryos. Southern blot hybridization analysis showed all eight clones to be derived from transgenic cells suggesting a growth advantage of cells carrying the activatedfps/fes gene. A cell line, Clone 166 (C166), established from one of these clones, was more fully characterized. C166 exhibits normal endothelial characteristics, such as rearrangement into tubelike structures when placed on Matrigel, expression of angiotensin converting enzyme, retention of cobblestone morphology at confluence, and the presence of cell surface receptors for acetylated low density lipoprotein. The cells constitutively express murine endothelial cell adhesion molecule VCAM-1 and the vascular addressin identified by antibody MECA-99. As expected, the cell line expresses high levels of the cytoplasmic protein-tyrosine kinase encoded by thefps/fes proto-oncogene. The clone we have described as well as other endothelial cell lines that we have established from the mouse embryonic yolk sac should prove useful for the study of endothelial cell differentiation and for the determination of the mechanisms underlying the establishment of organ-specific endothelial cell heterogeneity.     

动物气味的顶空取样技术及其在水貂肛腺成分分析中的应用

我们设计了一种用于动物气味的顶空 (headspace)取样装置 ,并结合溶剂解吸附和气质联用技术 ,通过对水貂 (Mustelavision)肛腺分泌物的挥发性成分的分析验证这种装置的可行性。出现 5个气谱峰 ,对应的质谱显示其分子量和分子式依次为峰 1:10 2 (C5H10 S)、峰 2 :10 4(C5H12 S)、峰 3:10 2 (C5H10 S)、峰 4:136(C5H12 S2 )和峰 5 :134 (C5H10 S2 )。峰 1、峰 3和峰 5分别为以前研究所鉴定出的 3种主要成分 :2 ,2 二甲基硫代环丁烷、2 乙基硫代环丁烷和 3,3 二甲基 1,2 二硫代环戊烷 ,2 ,2 二甲基硫代环丁烷为优势成分 ,组成无性别间差异。这些结果与以前研究一致 ,说明了这种顶空取样装置的可靠性。峰 2和峰 4两种成分以前在水貂肛腺中未曾发现 ,初步分析可能分别为 3 甲基 1 丙基硫醇和 1,5 戊二硫醇。尽管这两个成分有待进一步分析确定 ,但可以肯定分子量为 10 4和 136的成分不仅在水貂肛腺分泌物中没有发现过 ,而且在已经研究过的鼬属动物和食肉类的肛腺中都未发现过 ,能检测出更多的成分 ,说明这种方法的可靠性很高。     

Enhanced in vitro growth of murine fibroblast cells and preimplantation embryos cultured in medium supplemented with an amphipathic peptide.

Preliminary studies on the proliferative effects of lytic peptides were carried out using NIH 3T3 murine fibroblast cells and human lymphocytes. Cells were cultured in various concentrations of three different amphipathic peptides (SB-37, Shiva-1, and Vishnu), and enhanced proliferation was determined by uptake of 3H-thymidine with treated cells compared with control cultures. Enhanced proliferation of 3T3 cells was observed in cultures containing 50 microM or less SB-37. The primary study consisted of 263 four-cell- to eight-cell-stage mouse embryos from naturally bred mice and incubated in Whitten's medium containing 0.2, 1, or 10 microM of the amino terminus of an amphipathic cecropin B analog (Vishnu) or in Whitten's medium alone. Embryos were cultured to the hatched blastocyst stage, and effect of treatment was determined by the rate of growth to that stage of development. Statistical analysis revealed that culture in all three levels of Vishnu significantly accelerated in vitro growth of these stages of preimplantation embryos compared with controls. These results indicate that Vishnu promotes increased cleavage rates of embryos in vitro. A growth factor receptor clustering mechanism of action is proposed. This peptide may have some potential as an embryo culture medium additive to enhance in vitro growth rate.