Effect of norfloxacin on ultrastructure characteristics of the loach embryos

The ultrastructure of embryo cells of the loach (Misgurnus fossilis L.) at the stage of the first and the tenth blastomer divisions in the control and under the conditions of fluoroquinolone norfloxacin (5 and 25 mkg/ml) influences has been investigated. The effect of this antibiotic has resulted in significant ultrastructural changes of embryo cells, such as hypertrophy of channels of the smooth and rough endoplasmic reticulum, disorganization of mitochondrias and cytoplasm membrane destructions of embryo. It has been established that fluoroquinolone inhibited biosynthetic processes, directly influencing on the blastomer biosynthetic structures. Such results testify a high norfloxacin embryotoxicity.     

A cytoplasmic determinant for dorsal axis formation in an early embryo of Xenopus laevis

In Xenopus laevis, dorsal cells that arise at the future dorsal side of an early cleaving embryo have already acquired the ability to cause axis formation. Since the distribution of cytoplasmic components is markedly heterogeneous in an egg and embryo, it has been supposed that the dorsal cells are endowed with the activity to form axial structures by inheriting a unique cytoplasmic component or components localized in the dorsal region of an egg or embryo. However, there has been no direct evidence for this. To examine the activity of the cytoplasm of dorsal cells, we injected cytoplasm (dorsal cytoplasm) from dorsal vegetal cells of a Xenopus 16-cell embryo into ventral vegetal cells of a simultaneous recipient. The cytoplasm caused secondary axis formation in 42% of recipients. Histological examination revealed that well-developed secondary axes included notochord, as well as a neural tube and somites. However, injection of cytoplasm of ventral vegetal cells never caused secondary axis and most recipients became normal tailbud embryos. Furthermore, about two-thirds of ventral isolated halves injected with dorsal cytoplasm formed axial structures. These results show that dorsal, but not ventral, cytoplasm contains the component or components responsible for axis formation. This can be the first step towards identifying the molecular basis of dorsal axis formation.     

水稻中央细胞发育期间超微结构变化的观察

本文通过透射电镜对水稻受精前胚囊中央细胞发育过程中超微结构的变化进行观察。结果表明,八核胚囊形成后很快就进行细胞化形成7个细胞,其中刚形成的中央细胞由1个大液泡、2个极核（珠孔端和合点端各1个）和一些含有丰富细胞器的胞质组成。中央细胞以后的发育主要是极核的发育和极核周围胞质的变化。极核发育经历以下过程：a．2个核都膨大呈“椭圆”形。核周围胞质呈不对称分布。b．2个核分别向胚囊中央移动并相互靠近。之后2个极核调整排列方式,由纵排（即与胚囊纵轴平行）变成横排。此时期有细胞质“桥”联结珠孔端卵器、2个极核和合点端反足细胞器。c．横排的极核移向卵器,并排列于卵细胞之上。此时胚囊未明显膨大,但极核相靠近的两边核膜有许多处已形成“融合桥”,核周围的胞质也起较大的变化,如质体内淀粉消失和光面内质网增加等。极核进一步发育直至胚囊成熟期间,极核排列方式及其周围胞质组成未观察到明显的变化,但胚囊体积明显增大。     

Developmental changes in the subcellular structure of the seeds of Atropa belladonna

Subcellular changes in the embryo and endosperm of Atropa belladonna were studied at four developmental stages. The endosperm cells turn to storage cells much earlier than those of the embryo, which matures later. Cells of the cotyledon and radicle are very similar in structure. The young cells contain large osmiophilic spherosomes. The cytoplasm is filled with ribosomes but dictyosomes are very rare. Some proplastids, containing starch, and mitochondria are present in the early developmental stages but do not occur in the dormant cells. During ripening, the vacuoles of the endosperm cells and embryo develop into protein bodies. They become filled with protein material without any recognisable transport mechanism. Protein bodies have several electron-translucent globoid cavities and the protein mass contains a roundish or crystalline body. This body does not stain with potassium iodide but with periodic acid Schiff-reagent and protein stains, indicating that it contains glycoproteins. The embryo and endosperm cells of ripe Atropa seeds are very similar and filled with protein bodies and small spherosomes.     

Ultrastructure of endothelium in ovules of Penstemon gentianoides Poir. (Scrophulariaceae) at mature embryo sac phase

In this study ultrastructural differences between endothelial cells of different location in Penstemon gentianoides have been examined with electron microscope at mature embryo sac phase. Embryo sac is of the Polygonum type and surrounded by endothelium except the micropylar region. The cuticle is located primarily around the chalazal three-fourths of the embryo sac. Endothelium cells around the chalaza and toward the micropylar region are rich in cytoplasmic organelles. The cytoplasm of endothelial cells near the central cell has large vacuoles and few organelles. There are also plasmodesmas on the anticlinal walls of endothelial cells. The endothelium and the micropylar integumentary cells play a role in transport of metabolites into the embryo sac.     

Studies on the Changes of Cell Ultrastructure in the Course of Seed Germination of Bletilla striata Under Fungus Infection Conditions

Aided by the techniques of ultrathin section and electron microscopy, the changes of cell ultrastructure of seed germination of Bletilla striata was investigated. It was found that the seeds of B. striata were germinated easily among Orchidaceae, the large thin-wall cells of embryo contained a great amount of starch and lipid materials which were nutrients of seed germination. The differentiation and growth of the nutritive organ of B. striata would be accelerated after fungus infection. Fungus could penetrate seed coat in cell interstice, invaded, embryo through suspensor, and interspersed in several layers of embryonic ceils. Cytoplasm and organelles of embryo would disappear after the cells infected by fungus, and then endocytic plasmalemma produces some sacs enclosing and digesting hyphae. The hyphae with its tip inflation, relying on expansion-pressure of its cytoplasm, could penetrate cell wall of embryo. In addition, after invasion hyphae wall was significantly thickened by the deposition of the embryonic cytoplasm. In the end, the hyphae would be wholly collapsed and its degradated materials were used as nutrient for germination. The cells without penetration' by hyphae show vigrous metabolism activity in protocorms.     

Ultrastructural differentiation of glandular stomach (proventriculus) in chick embryo

Cytochemical characterization of mucosubstances of chick glanular stomach (proventriculus) changes from 15 days of development to postnatal and adult stages was studied. To corroborate these data cytochemical, ultrastructural and ultracytochemical study of chick embryo proventriculus from 7 to 20 days of development was performed. At the 7th day several layers of undifferentiated cells formed an epithelium which covered the walls of the glandular stomach. Mocosubstances were not found. Between the 9th and 5th day a single layer of cylindrical cells was encountered forming invaginations which originated deep glands. Three types of cells were separated from the above mentioned layer, dark, clear and undifferentiated. The dark cells had organelles which are involved in protein synthesis and the clear ones were rich in mitochondria. Argentaffine cells appeared at 15th day instead mucosubstances formed a thin coat on the epithelium at 9th day which increased at the end of development in the apical cytoplasm and gland cells. These observations demonstrate that proventriculus of chick embryo has ultrastructurally differentiated cells involved with enzymatic and hydrochloric acid secretion after the 9th day. These progressive events are correlated with the digestion process of yolk during embryogenesis. At the end of development the proventriculus has completely organized the glandular layer.     

小麦雌配子体发育过程中酸性磷酸酶活性定位

在小麦(Triticum aestivum L.)雌配子体发育过程中,胚囊周围邻近的珠心细胞退化降解,并出现很高的酸性磷酸酶反应,特别是合点部分最强。电镜细胞化学定位也表明退化珠心细胞质中有强烈的酸性磷酸酶活力,它们存在于多层环状的胞质结构中,而远离胚囊的非退化珠心细胞中无上述结构,酸性磷酸酶活性仅出现于液泡中。认为珠心细胞的退化是一种自溶现象。从功能大孢子至七细胞胚囊期,胚囊内部胞质酸性磷酸酶活性很低,合点与珠孔两端的反应强度无明显区別。后期成熟胚囊阶段,反足细胞中出现强烈酸性磷酸酶活性,中央细胞次之,而助细胞及卵细胞中很弱。     

The intracellular significance of pH, its dynamics and possible role in regulating cell functions]

The intracellular and intralysosomal pH were studied on living monolayer cell cultures SPEV (pig embryo kidney), CHC (Chinese hamster's fibroblasts), NGUK-1 (neurinoma of Gasser's gland of rat), and also on primary cell cultures of rat's hepatocytes and chick embryo fibroblasts. In cytoplasm and lysosomes of these cells were found out pH changes during cells cycle and cell cultivation. There was also showed a heterogeneity of different parts of cells and lysosomes, and circahoral pH oscillations were registered. So there was found a spatial and temporal pH mosaity of living cells. The probable role of intracellular pH changes via regulator of cell vital activity is discussed.     

水稻胚囊超微结构的研究

水稻(Oryza sativa L.)胚囊成熟时,卵细胞的合点端无细胞壁,核居细胞中部,细胞器集中在核周围,液泡分散于细胞周边区域。助细胞珠孔端有丝状器,合点端无壁,核位于细胞中部贴壁处,细胞器主要分布在珠孔端,液泡主要分布在合点端。开花前不久,一个助细胞退化。中央细胞为大液泡所占,两个极核靠近卵器而部分融合,细胞器集中在极核周围和靠近卵器处,与珠心相接的胚囊壁上有发达的内突。反足细胞多个形成群体,其增殖主要依靠无丝分裂与壁的自由生长,反足细胞含丰富活跃的细胞器,与珠心相接的壁上有发达的内突。开花后6小时双受精已完成,合子和两个助细胞合点端均形成完整壁。合子中开始形成多聚核糖体、液泡减小。退化助细胞含花粉管释放的物质,其合点端迴抱合子。极核已分裂成数个胚乳游离核,中央细胞中细胞器呈活化状态。反足细胞仍在继续增殖。讨论了卵细胞的极性、助细胞的退化、卵器与中央细胞间界壁的变化、反足细胞的分裂特点等问题。     

Coordinated cell-shape changes control epithelial movement in zebrafish and Drosophila

Epithelial morphogenesis depends on coordinated changes in cell shape, a process that is still poorly understood. During zebrafish epiboly and Drosophila dorsal closure, cell-shape changes at the epithelial margin are of critical importance. Here evidence is provided for a conserved mechanism of local actin and myosin 2 recruitment during theses events. It was found that during epiboly of the zebrafish embryo, the movement of the outer epithelium (enveloping layer) over the yolk cell surface involves the constriction of marginal cells. This process depends on the recruitment of actin and myosin 2 within the yolk cytoplasm along the margin of the enveloping layer. Actin and myosin 2 recruitment within the yolk cytoplasm requires the Ste20-like kinase Msn1, an orthologue of Drosophila Misshapen. Similarly, in Drosophila, actin and myosin 2 localization and cell constriction at the margin of the epidermis mediate dorsal closure and are controlled by Misshapen. Thus, this study has characterized a conserved mechanism underlying coordinated cell-shape changes during epithelial morphogenesis.     

Influence low-intensity laser irradiation on the ultrastructural organization of loach embryo cells

The ultrastructural organization of loach embryo cells (Misgurnus fossilis L.) at the stage of the first and the tenth embryo divisions was investigated under the influence of low intensity helium-neon laser irradiation of 5 min exposure. It was determined that the effect of laser irradiation led to ultrastructural changes: the shape of mitochondria and multivesicular bodies changes. The obtained results explain the possible mechanism of influence of low-intensity laser irradiation at the cellular level.     

小麦受精过程中酸性磷酸酶的超微细胞化学定位

小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ ）受精前成熟胚囊,除胚囊中央细胞的合点端细胞质中有酸性磷酸酶外,其余部位均未发现酸性磷酸酶。受精时期,以下部位存在酸性磷酸酶活性：卵细胞的细胞核内一部分染色质和细胞质中大部分线粒体;精、卵核融合时两核的核周腔内;退化助细胞合点端细胞质和一些液泡内;进入雌性细胞中的两个精核;胚囊各成员细胞的细胞壁及胚囊周围珠心细胞的细胞壁。二细胞原胚中未见有酸性磷酸酶。早期胚乳游离核染色质上有酸性磷酸酶。小麦受精过程酸性磷酸酶的分布特点可能与卵细胞生理状态的变化和细胞质中线粒体的改组、助细胞的退化、精核的生理状态以及精核与卵核的核膜融合等有关。     

The Ultracytochemical Localzation of Acid Phosphatase Activity in Wheat During Fertilization

No acid phosphatase activity was observed in the mature embryo sac of wheat (Triticum aestivum) except the chalazal cytoplasm Of the central cell before fertilization. During fertilization, acid phosphataseactivity was observed in the following loci: part of chromatin of the egg nucleus and most of the mitochondria in the egg cytoplasm; the perinuclear spaces of the egg and sperm nuclei at the fusion of the egg and sperm nuclei; the chalazal cytoplasm and some vacuoles of the degenerated synergid; two sperm nuclei within the cytoplasm of female cells; the cell wall of each cell of the embryo sac and that of the nucellar cells surrounding the embryo sac. No acid phosphatase was observed in the two-celled proembryo. Dense enzyme reaction product was localized in the chromatin of the free nuclei at early stage of the endosperm. The characteristic of acid phosphatase distribution during fertilization may be associated with the physiological change of the egg Cell, the reorganization of mitochondria in the egg cell cytoplasm, the degeneration of one of the two synergids, the physiological state of the sperm nuclei and the nuclear membrane fusion of the egg and sperm nuclei.     

Ultrastructural Studies on the Degeneration Processes in Wheat Nucellar Cells

During its development and enlargement, the embryo sac encroachesupon adjoining nucellar cells continuously, leading to their degeneration completely. Thefirst signs of degeneration appear in the vacuolated nucellar cells at a distance to theembryo sac. In the process, two types of degeneration are found in wheat nucellarcells. In type I the degeneration is carried out through the in situ autolysis of theircytoplasm. The ribosome density decreases drastically in the cytoplasm of the nucellarcells. Organelles therein become suspended in a more diluted cytoplasmic matrix. Debris of dissolved cytoplasmic components distribute throughout the cytoplasm andvacuoles. Chromatin masses in the nucleus decrease obviously or chromatin becomecondensed in the mean time. Degenerate cells of this type become empty and dead atlast, lying on the border of the embryo sac. Type Ⅱ of degeneration is quite contrary to the first, the process is carried out through the proliferation and dilation ofrough endoplasmic reticulum cisternae, and their engulfment and sequestering of thecytoplasmic components. Degeneration type Ⅱ is associated with the increasing affinityof dyes, such as lead, in the protoplast. Finally, plasma membrane and tonoplast breakdown, protoplast shrinks and converts to a dark disorganized mass. During the process of the degeneration type Ⅱ, a series of complicated changes occur in the nucleusand cytoplasm.     

Developmental changes in the inner epidermis of the bean seed coat

Summary The inner epidermis of the bean seed coat shows remarkable structural changes during seed development. At the globular stage of development, a moderately electron-dense substance begins to accumulate in the outer tangential and radial walls of the cells. The staining and fluorescence characteristics, together with the localization of peroxidase in the wall, suggest that this electron-dense material is a phenolic substance. At the same stage of embryo development, structural specialization can be detected in the cytoplasm of the epidermal cells with an increase in the abundance of organelles, especially the endoplasmic reticulum, mitochondria, and dictyosomes. These structural features are similar to those in the underlying branched parenchyma cells. As the seed rapidly expands during the maturation stage of embryo development, the epidermal cells and the inner layers of the branched parenchyma cells begin to degenerate. Small ruptures can be detected in the epidermis, exposing the branched parenchyma cells. These structural changes are discussed in relation to their possible functions during embryo development.     

Unusual electron-dense dome associates with compound plasmodesmata in the embryo-suspensor of genus Sedum (Crassulaceae)

Plasmodesmata ensure the continuity of cytoplasm between plant cells and play an important part in the intercellular communication and signal transduction. During the development of the suspensor of both Sedum acre L. and Sedum hispanicum L., changes in the ultrastructure of plasmodesmata and adjoining cytoplasm are observed. Numerous simple plasmodesmata are present in the inner wall of the two-celled embryo separating the basal cell from the apical cell. From the early-globular to the torpedo stage of embryo development, the part of the wall separating the basal cell from the first layer of the chalazal suspensor cells is perforated by unusual, compound plasmodesmata. The role and the sort of transport through these plasmodesmata are discussed.     

小麦受精过程的细胞化学研究

小麦成熟胚囊卵细胞中存在较多围核分布的淀粉粒和少量散布的脂类颗粒;两个助细胞中积累很多脂类,未见有淀粉粒存在;中央细胞中存在中等量均匀分布的淀粉粒和脂类颗粒。受精时期,胚囊内各细胞中淀粉粒变化不大。精卵核融合时,卵细胞和中央细胞中的脂类分别存在一个积累高峰。合子与相应时期游离核胚乳中的脂类颗粒均较少。原胚初期,每个原胚细胞及胚乳原生质中均积累较多脂类。珠孔附近的内珠被细胞中脂类颗粒较多,并存在一个有规律的变化。在观察的所有发育时期的胚珠中,均未发现贮存蛋白质。胚珠中脂类的一系列变化可能与雌性细胞的营养、胚胎发育初期的养料及花粉管的定向生长等有关     

Studies of Ultrastructure and ATPase Localization of Mature Embryo Sac in Vicia faba L.

Studies of ultrastructure and ATPase localization of the mature embryo sac in Vicia faba L. show that the egg cell has no cell wall at thechalazal end, it has a chalazally located nucleus and a large micropylar vacuole. There are many nuclear pores in the nuclear membrane. The cytoplasm is restricted around the nucleus. Dictyosome and mitochondria are few. There are some starch grains and lipid grains in the egg cytoplasm. There are no obvious differences between two synergids. No cell wall is seen at the chalazal end either, but there are some vesicles which project to vacuole of the central cell and fuse with its vacuolar membrane. Plasmodesmata connections occur within the synergid wall where it is adjacent to the central cell. The synergid has a micropylarly located nucleus and a chalazal vacuole, the nucleus is irregularly shaped. The synergid cytoplasm is rich in organelles. The filiform aparatus is of relatively heterogeneous structure. The central cell is occupied by a large vacuole and its cytoplasm is confined to a thin layer along the empryo sac wall, but is rich in various organelles, starch grains and lipid bodies. Nucleolar vacuoles are often present two polar nuclei. The nuclear membranes of two polar nuclei have partly fused. ATPase reactive product was located obviously at the endoplasmic reticulum in cytoplasm of the egg cell and central cell. The embryo sac wall consists of different density of osmiophilic layer. There are some wall ingrowths in chalazal region of the embryo sac. The long-shaped and cuneate cells of chalazal region are peculiar. Special tracks of ATPase reactive products are visible at their intercellular space which may be related to transportation of nutrients.     

Interaction of antibodies against nuclear envelope-associated proteins from rat liver nuclei with rodent and human cells

Antibodies have been prepared against the three major polypeptides of the nuclear pore complex-lamina fraction from rat liver nuclei. The three antisera prepared in chickens give similar results in indirect immunofluorescence microscopy. In rat embryo fibroblasts we observe bright fluorescence at the level of the nuclear envelope, with no fluorescence of the nuclear interior and little or no fluorescence of the cytoplasm. The nuclear envelope regions of rat hepatoma cells, mouse A9 cells, HeLa cells and rat liver nuclei also fluoresce brightly. HeLa nucleoids, which are depleted of nuclear envelope components, still exhibit specific fluorescence when reacted with these antibodies. Distribution of the antigens changes during mitosis. Fluorescence in the cytoplasm is observed following the breakdown of the nuclear envelope at prometaphase. The antigens appear to progressively accumulate at the periphery of the chromosomes until telophase. In late telophase fluorescence occurs predominantly at the periphery of the chromosomes where the new nuclear envelope is formed.