大獭蛤的胚胎、幼虫及稚贝的形态发育

在广西海洋研究所海滨公园育苗场进行大獭蛤(Lutraria maxima Jonas)的胚胎发育观察及人工育苗实验。实验亲贝取自北海市侨港码头。通过人工授精获取受精卵。取部分受精卵在实验室用显微镜进行胚胎发育观察及拍照，在囊胚期之前每隔10min取样1次，囊胚期之后每个半小时取样1次，胚胎发育观察至D形幼虫期。大部分受精卵在育苗池中进行人工育苗实验，育苗期间每天取样1次，在显微镜下进行观察、测量及拍照，并记录贝苗大小及发育期情况。实验期间水温变化为25．0～28．7℃，盐度为29．3‰～31．9‰。根据观察记录结果，得出大獭蛤胚胎发育及贝苗生长发育图谱，并描述了大獭蛤的胚胎发育及其幼虫、稚贝的形态。     

盘基网柄菌(Dictyostelium discoideum)KAX-3和AK127细胞形态发生和同工酶的比较研究

比较了盘基网柄菌(Dictyostelium discoideum)野生型细胞KAx-3和突变型细胞AK127在多细胞发育过程中的形态发生.两者有明显的区别;突变细胞的发育只能停留在细胞疏松聚集阶段,而野生型细胞能顺利完成整个发育过程.利用SDS-PAGE电泳比较分析了两者在重要发育阶段的三种同工酶:醋酶(EST)、苹果酸脱氢酶(MDH)和谷氨酸脱氢酶(GDH).结果发现AK127细胞发育阶段含有两种醋酶成分a和p,而KAX-3细胞中只有一种醋酶a;而且AK127细胞中苹果酸脱氢酶(MDH)含量在发育后14 h和16 h均高于KAX-3细胞;谷氨酸脱氢酶(GDH)同工酶在发育后14 h时相对含量高于KAX-3细胞,而在发育后16 h含量却低于KAX-3细胞.这些数据显示了两种类型细胞的同工酶有明显的差异;表明突变细胞基因的表达发生了一定的改变,由此说明了gp150分子在盘基网柄菌细胞发育中有重要作用.     

大鳞副泥鳅性腺发生和分化的组织学研究

通过人工繁殖技术获得大鳞副泥鳅幼体,采用石蜡显微切片技术对幼体性腺发生、分化的组织学特征进行了系统观察.结果表明大鳞副泥鳅是在出膜后14 d出现了未分化性腺,卵巢分化始于25日龄,到45日龄分化完全;精巢则是分化于30日龄,于75日龄分化为I期精巢.卵巢分化早于精巢.从性腺分化开始,将要发育为卵巢的性腺还表现为体积快速增大,向体腔中间靠拢,横截面变宽,而将要发育为精巢的性腺则呈两端尖中间稍突的梭形,增生并不明显,这些特征可能与雌雄性腺的发育和生殖细胞的分化速度有关,可以作为大鳞副泥鳅性腺早期分化的形态特征.     

On the genesis of the soil mantle of the region of Manaus,Central Amazonia,Brazil

Summary The dynamics of the forest to the north of Manaus is tightly linked to that of the soil. The latosol that covers the plateau, which supports a dense forest, consists from top to bottom of: (a) a brown, clayey organic horizon (0.3 m), (b) a yellow horizon, very rich in clay but permeable (from 0.3 to 4 m), (c) a nodular horizon rich in Al and Fe oxides (from 4 to 9 m), and (d) a horizon which still preserves the sedimentary structures of the parent sandstone, where quartz is intensely dissolved and kaolinite crystallizes in pores. In perfectly flat areas, the clay of the organic horizon is destroyed by acidocomplexolysis, and the dissolved Al is transported vertically by the drainage water. A part of this Al is used to make the gibbsite nodules of horizon (c), and the rest is used to make kaolinite in horizon (d). Because aluminum is thus conserved within any vertical prism, the rate of destruction of horizon (a) is equivalent to the rate of advance of the kaolinization zone into the sediment: the latosol is said to be in equilibrium, the surface remains perfectly flat as it slowly sinks, the quantity of kaolinite increases with time, and the silica released by quartz dissolution in the whole profile is exported by drainage water to the water table. In contrast, near drainage axes, however small initially, the drainage becomes inclined toward the axis. Part of the Al released by acidocomplexolysis of horizon (a) is now exported to rivers, and Al is no longer conserved within any given prism. The rate of advance of the kaolinization zone (d) into the sediment now becomes less than the rate of destruction of horizon (a) and the surface sinks faster than that of the surrounding plateau. After this differential podzolization has gone on long enough, it creates a network of geochemical valleys characterized by convex slopes and bounded by sandy soils (campinas). The vegetation becomes sparser and sparser. At the end, only some bushes and lichens survive on the white sand.Acknowledgments. The authors are indebted to Dr E. Merino (Dept. of Geology, Indiana University) for helpful criticisms and suggestions. This research was carried out in I.N.P.A. (Instituto Nacional de Pesquisas da Amazonia) and was financially supported by the CNPq-CNRS/ORSTOM conv.     

Morphogenesis of the division and encystment process of the ciliated protozoan Colpoda minima

We have investigated the main morphological features of the asexual division and encystment process in the ciliate Colpoda minima. It is a soil colpodid ciliate with a quite variable body size. The nuclear apparatus is composed of one ellipsoidal macronucleus and one lenticular micronucleus. The somatic infraciliature is made up of 69–101 kineties, 10–16 of which are postoral. The oral infraciliature is made up of two oral polykineties, the left one consists of 45–60 short oblique rows of kinetosomes whereas the right one is formed by a row of kinetosome pairs and many short rows of kinetosomes disposed without a regular arrangement. Cell division occurs in a division cyst and produces four tomites. Stomatogenesis is merotelokinetal and involves about 16–23 stomatogenic kineties. A macronuclear extrusion process takes place during cell division. The resting cyst is included in the partial-kinetosome-resorbing (PKR) group, and its cyst wall has two layers which are derived from different cystic precursors. During encystment, macronuclear division and chromatin extrusion (in some cases) have been observed. All of these characteristics of the life cycle of C. minima are compared and discussed with respect to those of other colpodid ciliates.     

BA和激素对‘Bonny Best’试管番茄愈伤组织形态发生的影响

用’Bonny Best’番茄品种的子叶和下胚轴作为外植体,在MS附加不同水平和比率的BA和2,4—D(或NAA)或IAA的培养基中,愈伤组织形态发生的情况是不同的。MS+BA4.44μM+2,4-D10μM(子叶),MS+BA0.44-4.44μM+2,4-D1—5μM(下胚轴)使外值体产生淡黄色疏松的愈伤组织,而且生长迅速。若2,4-D浓度低于5μM(子叶)或高于5μM(下胚轴)时,外植体形成白色紧密的愈伤组织,而且生长缓慢,固定2,4-D的浓度,BA浓度由高到低,所形成的愈伤组织的结构由紧密向疏松变化。愈伤组织的液体培养中也出现了类似现象。把愈伤组织转移到生茎培养基中,白色紧密的愈伤组织形成茎较为容易,培养21天后,茎的分化即开始。而疏松的愈伤组织的形态发生则经过了黄色疏松、深褐色胶状到白色紧密的变化。茎的分化出现较晚。愈伤组织培养时生长调节剂的水平对茎的分化有着直接的影响。较高水平的BA(22.2—44.4μM)+NAA10-40μM有利于茎的分化。把子叶和下胚轴切段培养在MS+BA22.2-44.4μM+IAA1-5μM的生茎培养基上,24—60天后,70％以上的外植体正常分化并伸长成茎,生枝率每个切段为3—4个。转移到MS培养基上,形成正常的带根幼苗。把下胚轴切段直接培养在没有激素的MS培养基上,三周后,45.8％的下胚轴形成正常幼苗,出枝率为1.0。把这些幼苗移栽到温室     

四角翁尼柯虫无性生殖中纤毛器及其基部纤维的分化

应用蛋白银方法,对淡水腹毛目纤毛虫四角翁尼柯虫细胞形态发生以及表膜下纤维系统的演化进行了进一步的研究,结果表明,该纤毛虫上海种群显示了与以前报告的模式有明显不同的现象,即在无性生殖期间,前仔虫口围带和口侧膜在老结构位置更新形成;左右缘棘毛的发生与老缘棘毛无明确关联,这不同于尖毛科的其他纤毛虫.棘毛基部纤维包括前纵纤维、后纵纤维、横纤维和放射纤维,其中左缘棘毛基部横纤维的定位与已知几种纤毛虫的同种结构不一样;细胞形态发生中,位于前后额腹横棘毛原基区的纤毛器及其基部纤维瓦解消失,左右缘棘毛原基区中左缘棘毛基部横纤维首先退化解体,这一过程与原基区的分化密切联系,并且老棘毛及其基部纤维对原基的形成和分化可能具有物质贡献;其他纤毛器及其基部纤维在皮层残留的时间较长,它们可能是伴随着老结构逐渐失去功能而退化瓦解的.     

寡毛双眉虫Diophrys oligothrix形态和形态发生的研究

报告了寡毛双眉虫(Diophrys. oligothrix) 的形态学特征以及它在无性分裂时期形态发生的全过程。观察了前仔虫口围带的形成过程,并将其与亲代的口围带进行比较,认为前仔虫口围带是经过重建的。从口器、大核等的情况反映出寡毛双眉虫与游仆虫、盾纤虫以及尾刺虫在进化上的关系。并认为前、后仔虫形成后仍继续恢复其典型的纤毛模式。     

Morphogenesis of human colon cancer cells with fetal rat mesenchymes in organ culture

Summary The morphogenesis and cytodifferentiation of human colon cancer cells (LS174T and HT29) were examined by combining cancer cells with fetal rat digestive-tract mesenchyme in organ culture. LS174T cells migrated into the mesenchyme to form glandular structures composed of single columnar cells with their nuclei oriented basally, while HT29 cells formed cell masses with little lumen formation. Immunohistochemical studies with antibodies against carcinoembryonic antigen and secretory components showed that the composition of cell surface glycoproteins was not necessarily reversed to the normal type, even when neoplastic cells exhibited normal glandular structures.This work was supported by grants-in-aid for Cancer Research from the Ministry of Education, Science, and Culture, Japan, and by the Veterans Administration Medical Research Service, USA. Y.S. Kim is the recipient of a Medical Investigator Award of the Veterans Administration.     

P311在肺泡发生中的作用初探

P311是一个由肺泡形成相关阶段相对于肺泡成熟期差减杂交库中获得的上游调节基因，为探讨其在肺泡发生过程中的可能作用，本以真实时间PCR(realtimePCR)和免疫组织化学方法确定了P311在肺器官发育过程中的表达特点，结果显示P311的表达无论在时间上还是在组织细胞分布上都与肺泡的发生密切相关．同时胎肺细胞植模型中，反义寡核苷酸阻断P311表达的研究亦显示P311在肺泡分隔膜形成过程中的重要性．