• Journal of Microbiology
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• v.40 no.2
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• pp.109-118
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• 2002

The present work is aimed at providing additional new pure cultures of oxalate utilizing bacteria and its preliminary characterization for further work in the field of oxalate-metabolism and taxonomic studies. The taxonomy of 14 mesophilic, aerobic oxalotrophic bacteria isolated by an enrichment culture technique from soils rhizosphers, and the juice of the petiole/stem tissue of plants was investigated. Isolates were characterized with 95 morphological, biochemical and physiological tests. Cellular lipid components and carotenoids of isolates were also studied as an aid to taxonomic characterization. All isolates were Gram-negative, oxidase and catalase positive and no growth factors were required. In addition to oxalates, some of the strains grow on methanol and/or formate. The taxonomic similarities among isolates, reference strains or previously reported oxalotrophic bacteria were analysed by using the Simple Matching (S/ sub SM/) and Jaccard (S$\_$J/) Coefficients. Clustering was performed by using the unweighted pair group method with arithmetic averages (UPGMA) algorithm. The oxalotrophic strains formed five major and two single-member clusters at the 70-86% similarity level. Based on the numerical taxonomy, isolates were separated into three phenotypic groups. Pink-pigmented strains belonged to Methylobacterium extorquens, yellow-pigmented strains were most similar to Pseudomonas sp. YOx and Xanthobacter autorophicus, and heterogeneous non-pigmented strains were closely related to genera Azospirillum, Ancylobacter, Burkholderia and Pseudomonas. New strains belonged to the genera Pseudomonas, Azospirillum and Ancylobacter that differ taxonomically from other known oxalate oxidizers were obtained. Numerical analysis indicated that some strains of the yellow-pigmented and nonpigmented clusters might represent new species.

• Journal of Microbiology
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• v.45 no.3
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• pp.227-233
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• 2007

In budding yeast, septin plays as a scaffold to recruits protein components and regulates crucial cellular events including bud site selection, bud morphogenesis, Cdc28 activation pathway, and cytokinesis. Phosphorylation of Bni5 isolated as a suppressor for septin defect is essential to Swe1-dependent regulation of bud morphogenesis and mitotic entry. The mechanism by which Bni5 regulates normal septin function is not completely understood. Here, we provide evidence that Bni5 phosphorylation is important for interaction with septin component Cdc11 and for timely delocalization from septin filament at late mitosis. Phosphorylation-deficient bni5-4A was synthetically lethal with $hof1{\Delta}$. bni5-4A cells had defective structure of septin ring and connected cell morphology, indicative of defects in cytokinesis. Two-hybrid analysis revealed that bni5-4A has a defect in direct interaction with Cdc11 and Cdc12. GFP-tagged bni5-4A was normally localized at mother-bud neck of budded cells before middle of mitosis. In contrast, at large-budded telophase cells, bni5-4A-GFP was defective in localization and disappeared from the neck approximately 2 min earlier than that of wild type, as evidenced by time-lapse analysis. Therefore, earlier delocalization of bni5-4A from septin filament is consistent with phosphorylation-dependent interaction with the septin component. These results suggest that timely de localization of Bni5 by phosphorylation is important for septin function and regulation of cytokinesis.

• KSBB Journal
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• v.13 no.4
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• pp.418-423
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• 1998

Cellular transfections with cationic liposomes are widely empolyed for gene and oligonucleotide transfer in vitro because of their safety and ease of use. However, they still suffer from the low transfection efficiency comparing with viral vectors. Substantial effort shave been focused on increasing transfection efficiency by supplementing the liposome/DNA complexes(lipoplex) with various components. In this work, we tired three kinds of supplements, Poly-L-lysine(PLL), transferrin and a mixture of anionic lipids(PS/PE/PC), to study their effects on gene transfer yield and gene expression efficiency. PLL, a polycationic polymer, enhanced gene transfer yield by 3 times but the gene expression efficiency was increased only by 1.5 times. this result implies that PLL can enhance the transfection efficiency mainly by increasing the rate of outermembrane transport of lipoplex into the cells. On the other hand, transferrin which can facilitate the gene transfer via ligand-receptor interaction gave not only increased gene transfer yield but also enhanced gen expression efficiency by 2.8 times. Transferrin seems to contribute to the escape of plasmid from endosomes through ligand-receptor recycle mechanism. When the cells were treated with a mixture of anionic lipids for 3 hours before the transfection, gene transfer yield was slightly decreased but the gene expression efficiency was enhanced by 1.9 times. This is presumably due to the accelerated liposome-plasmid dissociation by the anionic lipids, and the increased delivery of plasmid to the nucleus. According to these results, it is clear that the supplementation to ameliorate transfection efficiency with cationic liposomes should be contrived in the direction of increasing delivery of plasmid.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.2
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• pp.51-61
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• 2010

Objectives : The purpose of this study was to investigate antioxidant effects of curcumin from Curcumae Longae Radix. Methods : Using HepG2 Iiver-like cells, the antioxidant effects of curcumin, one of main components from Curcumae Longae Radix, and its analogues have been evaluated by measuring their effects on cytotoxicity induced by $H_2O_2$. Results : The pre-incubation for 6 hours with curcumin, bis-demethoxycurcumin, or dimethoxycurcumin protected HepG2 cells from $H_2O_2$-induced toxicity in a dose-dependent manner. However, tetrahydrocurcumin, one of curcumin metabolites, did not protect HepG2 cells from $H_2O_2$-induced toxicity. Interestingly, curcumin, bis-demethoxycurcumin, and dimethoxycurcumin were increased in the protein levels of heme oxygenase-1(HO-1) at concentrations that were also effective in cellular protection. In contrast, tetrahydrocurcumin did not induce HO-1 expression. Tin protoporphyrin-IX, an inhibitor of HO-1 activity, significantly abolished cytoprotection afforded by curcumin, bis-demethoxycurcumin and dimethoxycurcumin. Conclusions : These results demonstrate that curcumin, bis-demethoxycurcumin, and dimethoxycurcumin with two conjugated doble bonds on their structures may reduce $H_2O_2$-induced oxidative stress through HO-1 expression. HO-1 induction may be one of antioxidant pathways by which curcumin protects from oxidative stress-induced cytotoxicity.

• Applied Microscopy
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• v.29 no.2
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• pp.201-209
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• 1999

Remodeling of epithelial cells during wound healing in the skin of the Korean fire-bellied toad, Bombina orientalis, were examined using the scanning and transmission electron microscopical analyses. Artificial wounds were induced on the dorsal surface of the skin by excision, and reared in special cages with normal diets for up to 31 days after injury. From 4 days after wounding, regenerated epithelial cells are more rapidly migrated to wounding area, and remodeling of tissue components are proceeded gradually. Especially, formation of basal lamina between regenerated epithelium and dermis, and reconstruction of cellular junctions such as desmosomes (among the regenerated epithelial cells) and hemidesmosomes (between basal epithelial cells and basal lamina) are detected through fine structural analysis from 10 days after injury. Parakeratosis of regenerated epithelial cells observed during 16 to 19 days after wounding.

• Science of Emotion and Sensibility
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• v.7 no.2
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• pp.179-186
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• 2004

Acute spinal cord injury can produce neurologic injury with many physical, psychological and social ramifications. It has been shown that two separate components combine to produce neurologic damage in acute spinal cord injury : the primary and secondary injuries. The primary mediators of spinal cord injury include the actual mechanical tissue disruption which is a passive process that occurs immediately following the trauma. A secondary injury cascade follows which appears mediated by cellular and molecular processes working through complex mechanisms. Both the primary and secondary injury cascades produce cell death both in neuronal and supporting cell tissues. Recovery from central nervous system(CNS) disorders is hindered by the limited ability of the vertebrate CNS to regenerate injured cells, replace damaged myelin sheath, and re-establish functional neuronal connections. Of many CNS disorders including multiple sclerosis, stroke, and other trauma, spinal cord injury is one of the important diseases because of the direct association with the functional loss of the body. Previous studies suggest that substantial recovery of function might be achieved through regeneration of lost neuronal cells and remyelination of intact axon in spinal cord injury which is occurred frequently. As a therapeutic approach in spinal cord injury, recently, cell transplantation provides a potential solution for the treatment of spinal cord injury. This review describes the characteristics of spinal cord injury and presents some evidence supporting functional recovery after cell transplantation following spinal cord injury.

• The Korean Journal of Pharmacology
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• v.22 no.2
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• pp.144-150
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• 1986

Glutathione peroxidase might play an important role in the protection of cellular structures against oxidative challange by hydrogen peroxide and several organic hydroperoxides. It is widely accepted that allicin is biological active component of garlic, and allicin is easily degraded to diallyl disulfide and other components. This study was attempted to elucidate the effect of diallyl disulfide on some biological activities. It was observed that the activity of serum transaminase and glutathione level in liver were not changed by the treatment of diallyl disulfide. The liver cytosolic glutathione peroxidase activity was significantly enhanced. Whereas, mitochondrial enzyme activity was slightly increased. In the presence of diallyl disulfide in vitro, $V_{max}$ value of glutathione peroxidase for hydrogen peroxide was increased. On the other hand, Km value was not changed.

• Korean Journal of Medicinal Crop Science
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• v.25 no.5
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• pp.315-321
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• 2017

Background: Glycyrrhiza uralensis Radix (GR) is a crude drugs used in Asian countries that has been reported to prevent the progression of neurodegenerative diseases such as Alzheimer's disease. The present study examined whether GR and its active compounds, glycyrrhizic acid (GA) and isoliquiritigenin (IL), exerted protective effects on $H_2O_2$-induced oxidative damage in C6 glial cells. Methods and Results: We exposed C6 glial cells to hydrogen peroxide ($H_2O_2$) for 24 h and investigated the cellular response to GR and its active compounds by evaluating cell viability, reactivie oxygen species (ROS) production, and apoptosis-related protein expression. GR successfully mitigated the reduced cell viability and ROS production induced by $H_2O_2$ in C6 glial cells, IL and GA significantly increased the cell viability and decreased ROS production. In addition, IL and GA down-regulated apoptotic Baxdependent caspase-3 activation, but each compound exerted different mechanisms, i.e., IL dose-dependently decreased ROS production and, GA up-regulated anti-apoptotic Bcl-2 expression. Conclusions: These results demonstrated that GR and its active components, IL and GA, exhibit potential for use as natural neurodegenerative agents for the modulation of apoptosis in C6 glial cells.

• The Journal of Internal Korean Medicine
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• v.27 no.3
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• pp.688-697
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• 2006

Objectives : Peroxynitrite ($ONOO^-$), $O_2^-$ and nitric oxide (NO) are cytotoxic species that can oxidize several cellular components such as proteins. lipids and DNA. It has been implicated in the aging process and age-related disease such as Alzheimer's disease, rheumatoid arthritis, cancer and atherosclerosis. The aim of this study was to investigate $ONOO^-$ scavenging activities. and that of its precursors. NO and $O_2^-$ of Trigonellae Semen. Methods : To investigate $ONOO^-$. NO. $O_2^-$ scavenging activities, fluorescent probes, namely 2'.7'-dichlorodihydrofluorescein diacetate (DCFDA). 4.5-diaminofluorescein (DAF-2) and dihydrorhodamine 123 (DHR 123) were used. Protein expression levels of iNOS, COX-2, NF-${\kappa}B$, and VCAM-1 were assayed by western blot. Results : Trigonellae Semen markedly scavenged authentic $ONOO^-$, $O_2^-$ and NO. It also inhibited $ONOO^-$ induced by $O_2^-$ and NO which are derived from SIN-1. Furthermore. Trigonellae Semen inhibited $ONOO^-$, $O_2^-$ and NO generation in LPS-treated ICR mouse kidney postmitochondria. Trigonellae Semen inhibited gene expression of iNOS, COX-2, VCAM-l and NF-${\kappa}B$ (p65) activation. Conclusions : These results suggest that Trigonellae Semen is an effective $ONOO^-$, $O_2^-$ and NO scavenger. and that this substance has a potential role as an inhibitor of the aging process, and in therapy against age-related diseases.

• Toxicological Research
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• v.28 no.4
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• pp.241-248
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• 2012

Exposure of cells to ultraviolet B (UVB) radiation can induce production of free radicals and reactive oxygen species (ROS), which damage cellular components. In addition, these agents can stimulate the expression of matrix metalloproteinase (MMP) and decrease collagen synthesis in human skin cells. In this study, we examined the anti-photoaging effects of extracts of Tetraselmis suecica (W-TS). W-TS showed the strongest scavenging activity against 2,2-difenyl-1-picrylhydrazyl (DPPH) and peroxyl radicals, followed by superoxide anions from the xanthine/xanthine oxidase system. We observed that the levels of both intracellular ROS and lipid peroxidation significantly increased in UVB-irradiated human skin fibroblast cells. Furthermore, the activities of enzymatic antioxidants (e.g., superoxide dismutase) and the levels of non-enzymatic antioxidants (e.g., glutathione) significantly decreased in cells. However, W-TS pretreatment, at the maximum tested concentration, significantly decreased intracellular ROS and malondialdehyde (MDA) levels, and increased superoxide dismutase and glutathione levels in the cells. At this same concentration, W-TS did not show cytotoxicity. Type 1 procollagen and MMP-1 released were quantified using RT-PCR techniques. The results showed that W-TS protected type 1 procollagen against UVB-induced depletion in fibroblast cells in a dose-dependent manner via inhibition of UVB-induced MMP-1. Taken together, the results of the study suggest that W-TS effectively inhibits UVB-induced photoaging in skin fibroblasts by its strong anti-oxidant ability.