• KSBB Journal
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• v.13 no.2
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• pp.187-194
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• 1998

For mass production of polyhydroxyalkanoates (PHA), high cell density cultures of Alcaligenes eutrophus by fed-batch culture under phosphate-limitation condition has been investigated. PHA accumulation by the regulation by the regulation of initial phosphate concentration could be automatically induced, and high density cell culture above 200 g/L also could be successfully produced. The production of Poly-$\beta$-hydroxybutyrate (PHB) and dry cell weight increased with increasing the initial phosphate concentration. When the initial concentrations of phosphate were in the ranges of 1.5~4.5 g-PO$_4$/L, PHB and dry cell weight obtained were 83~266 g/L and 61~216 g/L, respectively, and PHB productivity was in the ranges of 1.35~3.10 g/L.h. When a mixture of glucose and propionic acid is used as carbon sources, poly(3-hydroxybutyrate-co-poly-3-hydroxyvalerate), P(3HB-co-3HV), could be also successfully produced under phosphate limitation condition. When the mole ratio of propionic acid to glucose in the feeding solution is 0.22, a final dry cell weight of 150 g/L and a P(3-HB-co-3HV) of 90 g/L were produced. Morphological changes and size distribution of PHB granules synthesized in A. eutrophus under phosphate-limitation condition are determined by TEM during the course of fed-batch. Mean granule diameters of PHB produced are in the range of 0.36~0.39 $\mu$m, and mean cell size was elongated from 0.54~0.59 $\mu$m$\times$ 1.3~1.5 $\mu$m to 0.83~0.89 $\mu$m $\times$2.0~2.3 $\mu$m. Phosphate concentration in media did not affect size distribution of PHB granule and cell.

• Animal cells and systems
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• v.12 no.4
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• pp.211-217
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• 2008

Bax, a pro-apoptotic member of Bcl-2 family proteins, plays a central role in the mitochondria-dependent apoptosis. Apoptotic signals induce the translocation of Bax from cytosol into the mitochondria, which triggers the release of apoptogenic molecules such as cytochrome C and apoptosis-inducing factor, AIF. Bax-inhibiting peptide(BIP) is a cell permeable peptide comprised of five amino acids designed from the Bax-interaction domain of Ku70. Because BIP inhibits Bax translocation and Bax-mediated release of cytochrome C, BIP suppresses Bax-dependent apoptosis. In this study, we observed that BIP inhibited staurosporine-induced neuronal death in cultured cerebral cortex and cerebellar granule cells, but BIP failed to rescue granule cells from trophic signal deprivation-induced neuronal death, although both staurosporine-induced and trophic signal deprivation-induced neuronal death are dependent on Bax. These findings suggest that the mechanisms of the Bax activation may differ depending on the type of cell death induction, and thus BIP exhibits selective suppression of a subtype of Bax-dependent neuronal death.

• Applied Microscopy
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• v.26 no.4
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• pp.411-420
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• 1996

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.

• Applied Microscopy
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• v.11 no.1
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• pp.39-50
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• 1981

An electron microscopical observation was carried out to compare the general shape of the mast cells and structures of granules inside the cells in the stomach of 5 species in 3 orders of Mammals. In convenience, the granules in the cytoplasm were abbreviated as follows: 1) Homogeneous granule, GR1 2) Particulate granule, GR2 a. Dark dense particulate granule, GR2-1 b. Less dense particulate granule, GR2-2 3) Reticular granule, GR5 a. Dark dense reticular granule, GR5-1 b. Light dense reticular granule, GR5-2 In Mammalia including goat, dog, cat, and hamster, most of cytoplasmic organelle were Golgi apparatus and mitochondria, and most of the cytoplasmic granules were highly densed GR1and GR2. However GR5-1 and GR5-2 appeared in guinea pig while one side sunken or crescent-like types occured in both dog and guinea pig. All mast cells were oval or spindle with cytoplasmic processes around the cell. There was also found vacuoles and vesicles in these cells. These results demonstrated that there was a morphological difference between species of vertebrate in the mast cells and their cytoplasmic granules. It was also suggested that a variety of structures of granules were closely related with the composition (histamine, heparin, serotonin, hyaluronic acid etc.) and mature of the granules.

• Applied Microscopy
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• v.17 no.1
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• pp.98-114
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• 1987

Degranulation of the rat peritoneal mast cell induced by intraperitoneal injection of horseradish peroxidase(HRP) was studied using light and electron microscopes. 1. Rat peritoneal mast cells in the Tyrode's buffered salt solution injected control group did not show any particular morphological changes following the specified time course. 2. Under the light microscope, the majority of mast cells observed 10 minutes after HRP injection were nearly the same as those of the control group. However, after 30 minutes, granule densities or staining properties of certain cells began to decrease and these appearances increased gradually until 12 hours after injection, at which time small groups of granules being stained pale-red or pink with toluidine blue were easily identified in the cytoplasm of many cells, and numerous extruded granuleg were scattered around these cells. 3. In the mast cells representing the early stage of degranulation induced by HRP, the electron densities of certain granules decreased as the size enlarged, and perigranular cavities were formed by perigranular membrane expansion. As a result, a thin cytoplasmic septum was formed between the expanded perigranular membrane and the cytoplasmic membrane in the cell periphery, and fusion of the adjacent perigranular membranes was observed in the inner side of the cell. 4. In some mast cells, one or two changes in the peripheral cytoplasmic septum could be seen. One was a focal rupture of the peripheral septum and the other was the formation of a saccule containing one or more vesicles. This saccule was thought to be used for granule-extrusion site and/or material absorptive apparatus judging from the morphological characteristics. 5. As the degranulation proceeded, the granule was extruded from the cell after partial rupture of the peripheral cytoplasmic septum. This phenomenon proceeded to-ward the inner side of the cell through the fused perigranular cavities, and consequently several distinct cavities containing a few unextruded membrane-free granules were formed throughout the cytoplasm after 12 hours. As a rule, the granule-extrusion sites were relatively fewer while the cytoplasmic cavities resulting from degranulation were more numerously observed. Thus, it was thought that the granule-extrusion sites tended to be restricted in the HRP-induced degranulation.

• Toxicological Research
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• v.12 no.1
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• pp.69-79
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• 1996

Primary culture of cerebellar neuronal cells derived from 8-day old Long-Evans rats was used. Pure granule cells, astrocytes or mixed cells culture systems were prepared. These cells were differentiated and developed synaptic connections. And the astrocytes were identified by immunostaining with glial fibrillary acidic protein (GFAP). Methamphetamine (MAP), which acts on dopaminergic system and cadmium (Cd), a toxic heavy metal, were applied and biochemical assays and electrophysiological studies were performed. $LC_50$ values estimated by MTT assay of MAP and Cd were 3 mM and 2$\mu M$ respectively. Cells were treated with 1 mM or 2 mM MAP and 1$\mu M$ $CdCl_2$ for 48 hour, and the incubation media were analyzed for the content of released LDH. MAP (2 mM) and Cd significantly increased the LDH release. Cell viability was decreased in both groups and some cytopathological changes like cell swelling or vacuolization were seen. The cerebellar granule cells were used for measuring membrane currents using whole-cell clamp technique. Sodium and potassium currents were not affected by MAP neither Cd, but calcium current was significantly reduced by Cd but not affected by MAP. Therefore, in vitro neurotoxicity test system using neuronaI cells and astrocytes cultures were established and can be used in screening of potential neurotoxic chemicals.

• Applied Microscopy
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• v.20 no.1
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• pp.1-16
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• 1990

The epidermal tissue of Korean planaria Phagocata vivida(Ijima et Kaburaki) is composed of the simple columnar epithelium. The ventral epidermis of this animals is thinner than the dorsal epidermis and has a furrow in the median line in which dark cell is observed. The clear cells which are electron-lucent are located either side of the dark cells. Those are compactly covered with long cilia. The free surface of the latero-ventral epidermis is tightly contacted with the earth and this epidermal free surface has a great number of short cilia, and a lot of C-type of basophilic granule cell are migrated into the cytoplasm of epithelium from mesenchyme passing through the basement membrane and then this granules are put out of latero-ventral free surface. Dorsal epidermis is thickest among the whole epidermis of these animals and the rhabdite granules are more distributed in dorsal epidermis than in ventral epidermis. According to the cytochemical and ultrastructural research, composed epidermis of this planaria are divided into nine type cells, that is, ciliated columnar epithelium, dark cell, mucous cell, rhabdite-forming cell, sunk round cell, A type, B type, C type and D type of basophilic granule cell.

• BMB Reports
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• v.49 no.2
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• pp.93-98
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• 2016

Germline stem cells (GSCs) are the best understood adult stem cell types in the nematode Caenorhabditis elegans, and have provided an important model system for studying stem cells and their cell fate in vivo, in mammals. In this review, we propose a mechanism that controls GSCs and their cell fate through selective activation, repression and mobilization of the specific mRNAs. This mechanism is acutely controlled by known signal transduction pathways (e.g., Notch signaling and Ras-ERK MAPK signaling pathways) and P granule (analogous to mammalian germ granule)-associated mRNA regulators (FBF-1, FBF-2, GLD-1, GLD-2, GLD-3, RNP-8 and IFE-1). Importantly, all regulators are highly conserved in many multi-cellular animals. Therefore, GSCs from a simple animal may provide broad insight into vertebrate stem cells (e.g., hematopoietic stem cells) and their cell fate specification.

• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.306-315
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• 1996

This study was performed to develop the biological treatment technology of wastewater polluted with heavy metals. The lead-tolerant microorganism, Pseudomonas aeruginosa which possessed the ability to accumulate lead, was isolated from the industrial wastewater polluted with various heavy metals. The characteristics of lead accumulation in the cells and the recovery of the lead there from were investigated. Removal rate of lead from the solution containing 100mg/l of lead by the lead-tolerant microorganism was more than 97% at 48 hours after inoculation with the microorganism. A large number of the electron-dense granules were found mainly on the cell wall and cell membrane fractions, when determined by transmission electron microscopy. Energy dispersive X-ray spectroscopy revealed that the electron-dense granules were lead complex with the substances binding heavy metals. The lead accumulated into cells was not desorbed by distilled water, but more than 87% of the lead accumulated was desorbed by 0.1M-EDTA. The residues of the cells after combustion at $550^{\circ}C$ amounted to about 30% of the dry weight of the cells. EDS analysis showed that the residues were relatively pure lead compounds containing more than 86% of lead.

• Journal of Photoscience
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• v.7 no.1
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• pp.31-34
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• 2000

The heterotrichous ciliate Stentor coeruieus shows a step-up photophobic response to visible light In the previous paper, the existence of GTP-binding proteins was confirmed by using the antisera against the carboxy terminal decapeptide of transducin $\alpha$ subunit. The photoreceptor, stentorin, is localized in the pigment granule. If the immunoreactive G-protein directly interacts with the photoreceptor stentorin, the G-protein expected to be located in the pigment granule rather than plasma membrane. To elucidate the function of the immunoreactive G-protein, the localization of the G-protein in Stentor coeruleus was studied. The results suggest that this G-protein is located in the myoneme involved in the contraction and extension of the cell rather than in the pigment granule.