Effects of induced pinocytotic activity and extreme temperatures on the morphology of golgi bodies in Amoeba proteus

Summary The morphology of the Golgi apparatus of Amoeba proteus can be influenced by substances inducing pinocytotic activity as well as by extreme temperatures. During the ingestion of a solution of 0.5% egg white the number of Golgi bodies decreases from 100% measured in control cells to 82% measured in cells showing induced pinocytosis. Simultaneously the ratio of the surface area of the cisternae at the proximal face to that of the vesicles at the distal face of single dictyosomes remains constant (1.74–1.72).The decrease and increase of the temperature of the culture medium to 4° C and 30° C respectively, causes the disappearance of most of the dictyosomes. After keeping the cells for 3–10 h at these temperatures the number of Golgi bodies was only 5–10% of the controls. A continued treatment with cold or warm culture medium leads to a partial reorganization of dictyosomes. After 15 h the number of Golgi bodies counted per cell returned to 57% at 4° C and 38% at 30° C. The ratio of the surface area of the Golgi cisternae to the surface area of the Golgi vesicles also alters under the influence of extreme temperatures. The values measured after treating the cells for 3 h, 4 h 10 h and 15 h at 4° C and 30° C amounted to 0.75, 0.85, 1.14 1.53 and 0.93, 0.38, 0.88, 1.60, respectively, compared to 1.72 of control amoebae.The different values of the ratio of the surface area of cisternae to that of vesicles indicate that there are strong morphological changes of single dictyosomes.     

Light and Electron Microscope Study of Dunaliella primolecta Butcher (Volvocida)*

SYNOPSIS. Light and electron microscope observations on Dunaliella primolecta Butcher from logarithmic and stationary phases of batch cultures are correlated. Except for the lack of a cell wall the fine structure has typical volvocid features. The transition from logarithmic to stationary phase is marked by changes in content and size of cytoplasmic vacuoles, accumulation of cytoplasmic lipid, accumulation of starch in the plastid matrix, and by the formation of autophagosome-like bodies. The organelles in stationary-phase flagellates are closely packed together because of the cytoplasmic lipid and starch-distended chloroplast. Organisms from logarithmic phase have an abundant ribosome-packed groundplasm supporting the organelles. In the cytochemical demonstration of acid phosphatase activity, Golgi cisternae and smooth and coated Golgi vesicles contain Gomori reaction product. The possible roles of the Golgi apparatus in this flagellate are discussed.     

The oral apparatus of tadpoles of Rana dalmatina, Bombina variegata, Bufo bufo, and Bufo viridis (Anura)

The morphology and development of the larval oral apparatus of Rana dalmatina, Bombina variegata, Bufo bufo, and Bufo viridis are described and compared using scanning electron microscopy. The species show different arrangements of the mouthparts. The small oral apparatus of R. dalmatina larvae has three labial tooth rows on the upper labium, while there are four tooth rows on the lower labium with a medial gap in row proximal to the mouth. The margins of the oral apparatus are defined by papillae that encircle the lower labium. B. variegata tadpoles have two upper labial tooth rows and three lower labial tooth rows that are uninterrupted, unlike the ones of R. dalmatina. The mouth is encircled by papillae that are larger than those of R. dalmatina. The oral discs of tadpoles of both B. bufo and B. viridis are similar. They are defined by two upper labial tooth rows (the second of which is interrupted by a medial gap) and by three lower tooth rows that differ in lengths in the two Bufo species. Both species develop papillae on the mouth angles and in two rows on the upper labium. Some morphological differences among the oral discs of R. dalmatina, B. variegata, B. bufo, and B. viridis tadpoles can be attributed to phylogenetic differences, but most can be related to their varying feeding habits and/or to their dietary specializations.     

Response of Audouinella saviana (Meneghini) Woelkerling (Nemaliales,Rhodophyta) cultures to monochromatic light

Audouinella saviana (Meneghini) Woelkerling was cultured at a constant temperature (24 °C) and different irradiances (from 1 µmol to 30 µmol photons m^–2 s^–1) of blue (430–470 nm) and green (500–560 nm) light in order to study its adaptive response. Modifications in colour, morphology and ultrastructure of the thalli, together with changes in pigment composition and in the spectral properties of chlorophyll a and R-phycoerythrin, were observed both by means of light and electron microscopy (TEM, SEM) and spectrophotometric and spectrofluorimetric analyses. In this paper we report the adaptive response of the seaweed to blue and green radiation by focussing on the cell wall and on the photosynthetic apparatus, particularly on phycobilisomes in situ and on R-PE after extraction. PBSs were fully structured only under blue light at low irradiance whilst they were absent under green light, whatever the irradiance, in spite of the high R-PE content. This fact, together with the spectral changes of R-PE, suggests adaptation at a molecular level, presumably referable to changes in aggregation state.     

苹果褐斑病菌侵染对苹果叶片光合机构功能的影响

为了探究苹果褐斑病菌侵染对苹果叶片光合机构的伤害机制,以‘寒富’苹果为试材,研究苹果褐斑病菌侵染对苹果叶片光合作用和光系统功能的影响。结果表明：随褐斑病菌侵染加重（叶片感病程度分0、1、2、3、4和5级）,叶片的叶绿素a含量和总叶绿素含量持续下降,其中2～5级与对照相比差异显著,病菌侵染提高了叶片类胡萝卜素含量,但仅以2级与对照差异显著。苹果褐斑病菌侵染显著降低了叶片的净光合速率（Pn）,3～5级病叶的Pn分别较对照下降44．9％、56．6％和70．3％,而胞间CO2浓度（Ci）上升,说明非气孔因素是光合作用的主要限制因子。褐斑病菌侵柒影响了光合电子传递效率,随病菌侵染程度加重,光系统Ⅱ反应中心、供体侧放氧复合体（Wk）和受体侧（Vj）受到的伤害加重,并引起苹果叶片PSII的光合性能指数用PIABS和PSI受体侧末端电子受体的量子产额（φRo）急剧下降。褐斑病菌侵染加重了苹果叶片的膜脂过氧化程度,1～5级感病叶片的丙二醛（MDA）含量均显著高于对照,引发超氧化物歧化酶（SOD）及过氧化物酶（POD）活性的上调。以上结果表明,苹果褐斑病菌侵染引起叶片光合色素降解,对PSII反应中心、受体侧和供体侧造成伤害,进一步影响了PSI的电子传递效率,并导致叶片膜脂过氧化,造成苹果叶片光合能力下降。     

濒危植物七子花繁殖器官的形态及其变异

对国家2级保护植物七子花(Heptacodium miconioides)的繁殖器官的形态及其变异进行了研究.结果显示:种群A的生境恶劣,花枝的开花数少,结实状况不及种群B,但因仅开基轮花的花序比例低和开三轮花的花序比例高,果实和种子的变异较大;而种群B的生境条件好,开花结实有明显的改善,但成熟种子的胚发育也不完全,且种子的最大值(由花序Ⅰ产生)不及种群A.说明七子花更适合于生境恶劣的条件下生长.另外,整枝疏花可以改善其结实状况,但效果不显著,说明七子花自身的营养调节能力差.因此,有性生殖障碍是七子花成为濒危物种的主要原因,要消除这种障碍必须研究种群的生态适应机制和种质的更新.     

铅、镉及其复合污染对蚕豆根尖细胞的诱变效应

应用蚕豆根尖微核技术研究了Cd(1mgL^-1～25mgL^-1)、Pb(1mgL^-1～25mgL^-1)及其复合污染对根尖细胞的毒害作用,分析了重金属及复合重金属污染对蚕豆根尖细胞有丝分裂和微核及染色体畸变的影响。结果表明：Cd、Pb及其复合处理对蚕豆根尖细胞有丝分裂及染色体行为存在不同程度的影响。具体表现为：低浓度促进细胞分裂,高浓度则抑制细胞分裂;对染色体畸变的影响表现为：当浓度为1．0mgL^-1时Cd即产生显著效应,而Pb浓度达10．0mgL^-1时,表现出稳定的,强度较大的诱变效应,且随浓度的增加毒害增强。Cd、Pb间存在交互作用,Cd达低浓度时与Pb的交互作用明显而高浓度则不明显,且Cd、Pb间存在部分拮抗作用。     

Yellow band and dark spot syndromes in Caribbean corals: distribution,rate of spread,cytology, and effects on abundance and division rate of zooxanthellae

Yellow band and dark spot syndromes have been frequently observed to affect coral species throughout the Caribbean within the last 10 years. These syndromes significantly impair at least three important reef-building species. Yellow band (also known as yellow blotch) appears as rings or blotches on Montastrea annularis throughout the Caribbean. The coral tissue necrosis occurs at a rate of approximately 0.6 cm/month. Transect measurements at various locations indicated that as many as 90% of M. annularis were affected by yellow band during 1997–98. Tissue samples reveal a 41–96.9% decrease in zooxanthellae/sample compared to healthy specimens, depending on distance from healthy tissue. Mitotic indices (MI) of zooxanthellae (symbiotic algae appearing as doublets) for M. annularis are 2.5%. MI in yellow band samples directly bordering healthy tissue are less than 0.9%, and zooxanthellae directly within the band bordering exposed skeleton had a mitotic index of 0.0%. This indicates impairment of zooxanthellae cell division in yellow band specimens. Zooxanthellae are not expelled and appear vacuolated and devoid of organelles. Dark spot, characterized by tissue necrosis as well as a depression of the colony surface, affects Stephanocoenia michelinii and Siderastrea siderea throughout the Caribbean. Transects showed that as many as 56% of S. michelinii and S. siderea showed signs of dark spot during 1997–98. Affected tissues of S. siderea died at a rate of 4.0 cm/month. In dark spot samples from S. siderea, the total number of zooxanthellae was 56% of that in healthy tissue; dark spot-affected specimens of S. michelinii showed a 14% decrease in the number of zooxanthellae compared to healthy tissue samples. Mitotic indices of zooxanthellae from healthy specimens of S. sidereawere 1.20% compared to 0.40% in dark spot samples. Mitotic indices of healthy S. michelinii were 1.54% compared to 0.23% in dark spot samples, also indicating a decrease in algal cell division. Zooxanthellae from dark spot tissue are swollen and darker in pigment. Due to the changes that are evident in the symbiotic algae, we suggest that both syndromes act primarily on the zooxanthellae symbiont, and secondarily on the cnidarian host.     

聚乙二醇对平邑甜茶叶片气孔器超微结构的影响

 采用透射电镜技术对聚乙二醇（PEG）模拟干旱处理的平邑甜茶(Malus hupehensis Rehd (pingyitiancha))叶片气孔器超微结构进行了观察,并对叶片气孔器超微结构制片方法进行了改进。所观察结果如下：1）PEG胁迫后保卫细胞中叶绿体数量增加,而叶绿体中淀粉粒数量呈下降趋势;2）PEG胁迫降低保卫细胞中线粒体的数量及破坏线粒体的超微结构;3）PEG胁迫使平邑甜茶保卫细胞中的液泡变小以致不明显。     

胃癌细胞高尔基体的蛋白质组学技术平台的建立

采用蔗糖密度梯度超速离心法分离纯化高尔基体,双向凝胶电泳（2-DE）分离高尔基体蛋白质,用ImageMaster 2D软件分析所得图谱,基质辅助激光解吸离子化飞行时间质谱(MALDI—TOF MS)鉴定蛋白质点等一系列亚细胞器蛋白质组学方法建立胃癌细胞内高尔基体的蛋白图谱。结果显示分离出的纯度较高的高尔基体建立了分辨率和重复性均较好的双向电泳图谱,运用质谱技术鉴定出12个蛋白质,包括蛋白合成相关蛋白、膜融合蛋白、调节蛋白、凋亡相关蛋白、运输蛋白、细胞增殖分化相关蛋白。通过亚细胞器分离纯化,双向电泳的蛋白分离及MALDI-TOF MS蛋白鉴定分析,首次成功建立了胃癌细胞SGC7901中高尔基体的蛋白质组学技术路线,为胃癌细胞内高尔基体功能的深入研究奠定了基础。