주암호의 유입하천중 이화학적 조건이 서로 다른 보성천과 동복천에서 채집된 남조 Microcystis aeruginosa Kutzing의 미세구조에 대한 형태학적 관찰을 시행하여 다음과 같은 결과를 얻었다. 수온과 pH를 제외한 다른 환경요인들은 두지점간에 큰 차이를 보였다. M. aeruginosa의 광학 및 전자현미경적 관찰 결과, 세포는 부정형 군체를 형성하며, 투명한 점액질로 싸여 있었다. 세포는 난형 또는 구형에 가깝고, 크기는 $2.61{\sim}5.40{\mu}m$의 범위로서, 평균 $3.54{\pm}0.19{\mu}m$였다. 세포질내에는 많은 다양한 구조물을 가지고 있으며, polyhedral bodies(carboxysomes), polyphosphate, cyanophycin granules 외에 photosynthetic lamellae와 gas vacuoles 등이 비교적 뚜렷하였다. 두 채집장소간의 형태학적 차이는 보이지 않았으나, 영양염류 수준이 높은 표본에서 polyphosphate와 cyanophycin granules이 숫적 증가를 보였다. 세포분열은 이분법으로 초기에 정중앙부의 좌우로부터 합입이 일어났으며, 주로 세포벽의 제1층과 제2층이 관여하였다. 세포벽의 외부층은 크게 두가지 형태의 filaments층이 잘 발달되어 있었다.

The microwave fixator has recently been introduced in morphological research. The present study was carried out to investigate the ultrastructural effects of microwave fixation of rat brain. kidney, liver and skeletal muscle tissues. The results are as follows: In the case of microwave fixed cerebrum. the cytoplasmic processes of neurons and the various membranous organelles such as nuclear envelope, mitochondria, rough endoplasmic reticulum and Golgi apparatus were well preserved, The myelin sheath wrapping neuronal axon was prominent. Microwave fixed hepatocytes showed the microvilli on the free surface of bile canaliculus, the evident nucleolar components, and typical organelles. In nephron, ultrastructures of glomerulus and Bowman's capsule were preserved, and also tubular wall were structurally observed. Among the skeletal muscle cells, plentiful collagen fibers were appeared, myofibrils and mitochondria were typically observed. In conclusion, the microwave fixation procedures result in an good preservation of the tissues and would be time- and reagent-saving.

A zinc-specific method (selenium method) has been employed to identify the zinc-containing cells in the cerebellum of the rats. When rats were allowed to survive 24 hours after the sodium selenite administration, zinc selenide reaction products formed in zinc-containing cellular boutons are retrogradely transported to the somata of those boutons. And the zinc selenide products accumulated in somata of the cells can be rendered visible by silver amplification of developer. Zinc-containing cells identified by the method were Bergmann glial and granule cells. Labeled zinc-containing cells were absent in molecular layer and white matter of the cerebellum. In ultrastructural level, the zinc selenide products were located in lysosomes of somata of the zinc-containing cells.

The endocrine cells in the midgut epithelium of the Japanese cockroach, Periplaneta japonica were observed by the light and electron microscopy. The midgut epithelium of the last instar larva and adult cockroach consisted of principal columnar cells, regenerative cells, and secretory granular cells. Midgut endocrine cells were positioned basally as a cone-shaped single cell in the epithelium or underneath the regenerative crypt cells. When midgut epithelium grows and the cell composing it transforms, between the endocrine cells and regenerative cells were made desmosome type junction and large vesicular shaped stretches of loose contact. The endocrine cells were characterized by a clear cytoplasm with abundant Golgi complex and numerous secretory granules. The secretory granules in the cell were spherical and electron dense with their diameter of $200{\sim}400nm$. The secretory granules have been observed as discharged by exocytosis on the basal and lateral side of the cell.

This experiment was performed to study the ultrastructural changes of the juxtaglomerular cell of mice following subcutaneous injection of heavy metallic agents. Male mice were divided into normal and experimental groups. The mice were subcutaneouly injected with $HgCl_2$ (2mg, 5mg or 10 mg/Kg/BW) or with $K_{2}Cr_{2}O_7$(5 mg, 10 mg or 20 mg/Kg/BW). Mice were sacrificed on 6 hours, 3 days and 14 days after the injection. Kidneys were fixed in the 2.5% glutaraldehyde-1.5% paraformaldehyde solution, followed by refixation in the 1% osmium tetroxide solution. Dehydrated blocks were embedded in araldite mixture. The sections were cut on a LKB-V ultratome, and ultrathin sections stained with uranyl acetate and lead citrate were observed with JEM 100CX II electron microscope. The results were as follow: 1. Juxtaglomerular cell of the experimental groups showed some alterations, especially in the structures of protein synthesis including dilations and degradations of granular endoplasmic reticula, atrophy of Golgi complex, and numerous free ribosomes in the cytoplasm. 2. Juxtaglomerular cells treated groups showed a number of vacuoles, protogranules and some myelin figures in the cytoplasm, especially in the earlier groups. 3. Juxtaglomerular cells of treated groups, contained a large number of secretory granules showing variable electron densities and pleomorphism in later groups (2 weeks). From the above results, it was concluded that, the mercuric chloride or potassium bichromate induces acute renin release from juxtaglomerular cells of the mice, but many juxtaglomerular cells may secrete prematured secretory granules, or the synthetic system of the cell can not perform normal function.

Fracture surfaces of materials contain useful information ranging from crack path to the mechanism of fracture. Since limitation of electron transparency requires a sample in the form of thin foil for TEM observations, it is impossible to extract such information directly from the fracture surfaces. In this study, the method of surface replication from the ceramic fracture surface is employed to characterize the process of crack propagation in ceramic matrix composites using TEM analysis. The surface replica from the fracture surface in ceramic materials provides detailed surface morphology and more importantly, loosened particles on the fracture surface are collected. Electron diffraction and chemical composition analyses of these particles reveal crack path in the specimen. Furthermore, one can determine the mode of fracture by observing the fracture surface morphology from the image of replica. Two examples are given to illustrate the potential of the surface replication technique. In the first example, apparent toughness increase in $B_{4}C-Al$ composites at high strain rate is investigated by surface replication to elucidate the mechanism of fracture at different strain rates. The polytypes of SiC formed during the sintering of SiC-AlN composite and their effect on the fracture behavior of SiC-AlN composite are analyzed in the second example.

Water storage cells (WSCs) in the leaf succulent Orostachys malacophyllus have been studied to understand their adaptive nature to its coastal habitat employing the electron microscopy. Attention has been paid to the features of vacuoles and plasmodesmata in this study, since leaf tissues in O. malacaphyllus are under continous physiological drought due to its occurrence in the shore-line environment. The WSCs occupied almost all of the leaf volume and appeared empty at low magnifications. Among the WSCs, small rudimentary vascular bundles were scattered throughout the internal volume. However, in high magnification the WSCs were vacuolate in most cases and vacuolization into a well-developed huge central vacuole was very common phenomenon. Such vacuolization has been detected within the vacuoles as well as within the cytoplasms. Well-developed plasmodesmata were often found in cells appeared to be mucilagenous. Moreover, plasmodesmata being involved in the secretion of materials or structures were even encountered. Thus, vacuolization from various sizes of vacuoles in the WSCs to have a huge central vacuole seems playing an important role in adapting the plant itself to its coastal habitat.

본 연구에서는 담즙산과 cholesterol 및 phospholipid가 흰쥐 간세포내 소기관에 미치는 영향을 조사하여 이들 담즙물의 수송기전을 알아 보고져 하였다. 정상군과 각 실험군에서 관찰된 Golgi장치는 거의가 cis side를 담세관으로 향하고 있었다. 각 실험군에서는 ER과 Golgi 장치 및 용해소체 등 소기관의 수적 증가, 소조의 팽대, budding 등이 관찰되었다. Dehydrocholic acid 투여군에서는 cis Golgi cistern의 선상 팽대을 많이 볼 수 있었는데 공포(vacuole)들은 담세관과 Golgi 장치사이에서 관찰되었으며 ER과 담세관 사이에서도 관찰할 수 있었다. Cholesterol 투여군과 Phosphotidylcholine 투여군에는 Golgi 장치의 모든 소조들이 팽대되어 있었으며 ER 유래의 공포와 용헤소체가 증가되어 있었는데 용해소체의 증가는 특히 cholesterol 투여군에서 현져하였다. 이상의 소견으로 미루어 담즙성분의 분비에 관여하는 주된 세포내 소기관은 ER과 Golgi 장치 및 용해소체로 추정된다. 그러나 dehydrocholic acid는 ER과 cis Golgi 소조 유래의 공포에 의해 분비되며 Cholesterol과 phosphatidylcholine은 ER에서 또는 trans Golgi 소조을 거친 후 용해소체를 통해서 배출될 것으로 추정되는데 특히 cholesterol은 용해소체를 통해서 빈번히 배출될 것으로 생각된다.

Thin epilayer structures of GaAs/AlAs/InGaAs, grown by Molecular Beam Epitaxy, were investigated by high resolution transmission electron microscopy, Image in the [110] zone axis was taken and compared with the calculated images. The supercell structure which contains GaAs, AlAs and InGaAs layers was designed and was employed in the image calculation with MacTempas computer program. Good agreement was shown between experimental image and a set of calculated images with varying defocus and sample thickness.