• Korean Journal of Plant Tissue Culture
• /
• v.26 no.3
• /
• pp.183-187
• /
• 1999

To establish an efficient screening system for new herbicides using plant cultured cells, responses of tobacco photomixotrophic cultured (PH) cells to various herbicides with different modes of action were surveyed by measuring the cell growth and ion conductivity in medium. The cells were cultured in Murashige and Skoog (MS) medium containing 0.7mg/L 2,4-D, 0.3mg/L kinetin and 30 g/L sucrose at $25^{\circ}C$ in the light (100 rpm). Chemicals were treated to suspension cultures of tobacco PH cells at the time of subculture. The cell growth and ion conductivity in the medium were investigated on 12 days after chemical treatment. The ion conductivity assay gave well correlated results to the cell growth inhibition data. The responses of tobacco PM cells were dependent on the modes of action of chemicals tested. Atrazine, an inhibitor of photosynthetic electron transport (PET), strongly inhibited both the cell membrane and cell growth ($IC_{50}$/, about 1 $\mu$M). Butachlor (an inhibitor of cell division), glufosinate (an inhibitor of amino acid biosynthesis), and fluridone (an inhibitor of carotenoid biosynthesis) showed a dose-dependent inhibition. However, Quinclorac, a herbicide with an auxin activity, did not affect the cell growth and ion leakage. These results suggested that tobacco PM cells is suitable materials for the simple screening of new herbicides such as PET, amino acid biosynthesis, ceil division inhibitors by measuring the cell growth and ion conductivity.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.24 no.3
• /
• pp.310-320
• /
• 2014

Backgrounds: Endotoxin, which found in the outer membrane of the gram-negative bacteria cell wall, makes up almost all of the lipopolysaccharide(LPS). When people are exposed to endotoxin,it can result in diverse health effects such as an airway irritation and inflammation, fever, malaise, bronchitis, allergic asthma, toxic pneumonitis, hypersensitivity lung disease. Cases among the elderly, children or pregnant can occur more frequently than a healthy adult if they are repeatedly exposed to the existing endotoxin. Therefore, we investigated and assessed the environmental characteristics associated with the airborne endotoxin concentration level in six hospital lobbies. Method: Endotoxin from indoor air in six hospital lobbies was measured by an area sampling method and analyzed according to American Society for Testing and Materials International(ASTM international) E2144-01. Total suspended particulate(TSP), carbon dioxide($CO_2$), temperature and humidity were also measured by using direct reading measurements or airborne sampling equipment at the same time. Environmental characteristics were appropriately divided into two or three groups for a statistics analysis. One-way analysis variable(one-way ANOVA) was used to examine a difference of the endotoxin concentration, depending on the environmental characteristics. In addition, only variables with p-value(p<0.25) were eventually designed to the best model by using multiple regression analysis. Results: The correlation analysis result indicated that TSP(p=0.003) and $CO_2$(p<0.0001) levels were significantly associated with endotoxin concentration levels. In contrast, temperature(p<0.068) and humidity(p<0.365) were not associated with endotoxin concentration. Levels of endotoxin concentration were statistically different among the environmental characteristics of Service time(p=0.01), Establishment of hospital(p<0.001), Scale of hospital(p=0.01), Day average people using hospital(p=0.03), Cleaning time of lobby(p=0.05), Season(p<0.001), and Cleaning of ventilation system(p<0.001) according to ANOVA. Finally, the best model(Adjusted R-square=72%) that we designed through a multiple regression test included environmental characteristics related to Service time, Area of lobby, Season, Cleaning of ventilation system, and Temperature. Conclusions: According to this study, our result showed a normal level of endotoxin concentration in the hospital lobbies and found environmental management methods to reduce the level of endotoxin concentration to a minimum. Consequently, this study recognized to be requirement for the management of ventilation systems and an indoor temperature in order to reduce the level of endotoxin concentration in the hospital lobbies.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.7 no.2
• /
• pp.156-162
• /
• 1995

A numerical method for a 2-D oil boom model considering the flexibility of skirt has been developed The neater is assumed rigid and the skirt is tensioned membrane having a point mass at its end The fluid motion is potential. The kinematic condition which demands the continuity of the displacement is imposed at the joint between the floater and the skirt. The dynamic condition for the point mass is imposed at the bottom end of the skirt. The numerical method is based on the Green's function method in the frame of linear potential theory. It finds it's solution simultaneously from the total system of three equations, integral equation, the equation of motion of the floater and the equilibrium equation of the deformation of the skirt. Integral equation is derived by applying the Green's theorem to radiation potential and Green's function. Proper descretization of those three equations leads to the system of a linear algebraic equation. Due to the flexibility of skirt the motion of floater can be diminished in some range of wave frequency and furthermore the mechanism of resonance of the oil boom can be changed. The motion responses of various oil booms have been compared varying the length of the skirt and the point mass. The numerical method has been validated indirectly from the good correspondence between the motion responses of the flexible skirt model and the rigid skirt model in low frequency limit.

• Korean Journal of Food Science and Technology
• /
• v.52 no.3
• /
• pp.263-273
• /
• 2020

In this study, in order to confirm the ameliorative effects of onion (Allium cepa L.) flesh and peel on amyloidbeta (Aβ)-induced cognitive dysfunction, we evaluated their in vitro neuroprotection and in vivo cognitive functions. As the result of in vitro neuroprotection, the protective effect of the ethyl acetate fraction of onion flesh (EOF) on Aβ-induced cytotoxicity was similar to that of the ethyl acetate fraction of onion peel (EOP). In the behavioral tests, the EOF and EOP effectively improved the Aβ-induced learning and memory impairments. For this reason, it could be concluded that the EOF and EOP improved the antioxidant activities (superoxide dismutase, oxidized glutathione/total glutathione, and malondialdehyde) in brain tissue. In addition, the EOF and EOP effectively activated mitochondrial functions by protecting the mitochondrial membrane potential, ATP, mitochondria-mediated protein (BAX and cytochrome c), and caspase 3/7 activities. The EOF and EOP also improved the cholinergic system (acetylcholinesterase and acetylcholine). Therefore, we suggest that onion could be used for management of Aβ-induced cognitive dysfunction.

• Food Science of Animal Resources
• /
• v.26 no.3
• /
• pp.402-409
• /
• 2006

Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.

• Microbiology and Biotechnology Letters
• /
• v.38 no.4
• /
• pp.349-361
• /
• 2010

In this review, the current knowledge of the carbon metabolism and global carbon regulation in Corynebacterium glutamicum are summarized. C. gluamicum has phosphotransferase system (PTS) for the utilization of sucrose, glucose, and fructose. C. glutamicum does not show any preference for glucose when various sugars or organic acids are present with glucose, and thus cometabolizes glucose with other sugars or organic acids. The molecular mechanism of global carbon regulation such as carbon catabolite repression (CCR) in C. glutamicum is quite different to that in Gram-negative or low-GC Gram-positive bacteria. GlxR (glyoxylate bypass regulator) in C. glutamicum is the cyclic AMP receptor protein (CRP) homologue of E. coli. GlxR has been reported to regulate genes involved in not only glyoxylate bypass, but also central carbon metabolism and CCR including glycolysis, gluconeogenesis, and tricarboxylic acid (TCA) cycle. Therefore, GlxR has been suggested as a global transcriptional regulator for the regulation of diverse physiological processes as well as carbon metabolism. Adenylate cyclase of C. glutamicum is a membrane protein belonging to class III adenylate cyclases, thus it could possibly be a sensor for some external signal, thereby modulating cAMP level in response to environmental stimuli. In addition to GlxR, three additional transcriptional regulators like RamB, RamA, and SugR are also involved in regulating the expression of many genes of carbon metabolism. Finally, recent approaches for constructing new pathways for the utilization of new carbon sources, and strategies for enhancing amino acid production through genetic modification of carbon metabolism or regulatory network are described.

• Journal of Korean Association for Spatial Structures
• /
• v.7 no.2 s.24
• /
• pp.97-104
• /
• 2007

Recently, the demand of the large span structures has been increasing. The large span structures include such a large scaled structures such as: the shell structure, the space frame structure, the membrane structure and the cable structure, etc. The large span structures are supposed to be confirmed and issued carefully at the initial process of the design besides the construction engineering aspects because of the structural specific cause that should solve and accomodate those large and wide space without columns. In the field of the large span structure construction, the erection construction method has been regarded as a major affected aspects on the construction cost, construction term, and stability. In the field of the large span structure construction, there are various construction method and system could be applied depends on the condition of the construction site and other circumstances such a major construction method as: the element method, the block method, the sliding method, the lift-up method and complexed method, etc. In this study, as the case study of the erection construction method of the large span structures, after survey and study that those existing large span structures construction cases which had applied and adopted the election construction method and analysis and classify into the Uoups by the size, span, ceiling height, structural system in odor to supply and suggest the data for the enhancement and development in the field of the erection construction method as a efficient structural solution of the large span structure construction.

• Journal of Life Science
• /
• v.22 no.9
• /
• pp.1145-1151
• /
• 2012

Aspirin and its deacetylated form, sodium salicylate (NaSal), have been shown to exert chemopreventive activities against many human cancers including those of the colon, lung, and breast. Previously, we showed that combined treatment of NaSal and genistein synergistically induced apoptosis in A549 lung cancer cells, indicating that these two natural chemicals could be used in combination for cancer therapy. In this study, we examined effects of NaSal/genistein combined treatment on other cancer cells and in three-dimensional multicellular tumor spheroid (MTS) and in an in vitro solid tumor model. We found that the combined treatment induces apoptosis in the HCT116 cells and the A549 cells, but not in the MCF-7 cells. Interestingly, the MCF-7 cells responded to the NaSal/genistein combined treatment by undergoing cell death when they were cultivated as MTS. The combined treatment induced apoptosis at an earlier stage in the MCF-7 MTS culture. However, when the MCF-7 MTS was cultivated for a longer period, it induced necrosis rather than apoptosis. We further found that the apoptotic pattern observed in MCF-7 MTS was incomplete: the chromatins were condensed and fragmented, but the nuclear membrane was still intact. Taken together, these results demonstrate that the NaSal/genistein combined treatment induces incomplete apoptosis and necrosis in the MCF-7 MTS culture system.

• The Korean Journal of Physiology
• /
• v.29 no.1
• /
• pp.69-80
• /
• 1995

Renal proximal tubular hypertrophy and hyperfunction are known to be early manifestations of experimental and human diabetes. As the hypertrophy and hyperfunction have been suggested to be central components in the progression to renal failure, an understanding of their underlying causes is potentially important for the development of therapy. A primary rabbit kidney proximal tubule cell culture system was utilized to evaluate the possibility that the renal proximal tubular hypertrophy and hyperfunction observed in vivo in diabetes mellitus, can be attributed to effects of elevated glucose levels on membrane transport systems. Primary cultures of rabbit proximal tubules, which achieved confluence at 10 days, exhibited brush-border characteristics typical of proximal tubular cells. Northern analysis indicated $2.2{\sim}2.3$ and 2.0 kb Na/glucose cotransporter RNA species appeared in fresh and cultured proximal tubule cells after confluence, repectively. The cultured cells showed reduced Na/glucose cotransporter activity compared to fresh proximal tubules. Primary cultured proximal tubule cells incubated in medium containing 20 mM glucose have reduced ${\alpha}-MG$ transport compared to cells grown in 5 mM glucose. In the proximal tubule cultures incubated in medium containing 5 mM or 20 mM glucose, phlorizin at 0.5 mM inhibited 0.5 mM ${\alpha}-MG$ uptake by 84.35% or 91.85%, respectively. The uptake of 0.5 mM ${\alpha}-MG$ was similarly inhibited by 0.1 mM ouabain (41.97% or 48.03% inhibition was observed, respectively). In addition, ${\alpha}-MG$ uptake was inhibited to a greater extent when $Na^{+}$ was omitted from the uptake buffer (81.86% or 86.73% inhibition was observed, respectively). In cell homogenates derived from the primary cells grown in 5 mM glucose medium, the specific activity of the Na/K-ATPase $(6.17{\pm}1.27\;{\mu}mole\;Pi/mg\;protein/hr)$ was 1.56 fold lower than the values in cell homogenates treated with 360 mg/dl D-glucose, 20 mM $(9.67{\pm}1.22\;{\mu}mole\;Pi/mg\;protein/hr)$. Total $Rb^{+}$ uptake occurred at a significantly higher rate (1.60 fold increase) in primary cultured rabbit kidney proximal tubule cell monolayers incubated in 20 mM glucose medium $(10.48{\pm}2.45\;nM/mg\;protein/min)$ as compared with parallel cultures in 5 mM glucose medium. $Rb^{+}$ uptake rate in 5 mM glucose medium was reduced by 28% when the cultures were incubated with 1 mM ouabain. The increase of the $Rb^{+}$ uptake by rabbit kidney proximal tubule cells in 20 mM glucose could be attributed primarily to an increase in the rate of ouabain-sensitive $Rb^{+}$ uptake $(5\;mM\;to\;20\;mM;\;4.68{\pm}0.85\;to\;8.38{\pm}1.37\;nM/mg\;protein/min)$. In conclusion, the activity of the renal proximal tubular Na,K-ATPase is elevated in high glucose concentration. In contrast, the activity of the Nafglucose cotransport system is inhibited.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.10
• /
• pp.1343-1349
• /
• 2012

Most of the Helicobacter pylori strains containing the cag pathogenicity island (PAI) have been associated with more severe gastric disease in infected humans. The cag PAI is composed of 27 proteins, and some of the components are required for CagA translocation into host cells as well as induction of proinflammatory cytokines, such as interleukin-8 (IL-8); however, the exact function of most of the components remains unknown or poorly characterized. In this study, we demonstrated that CagT (HP0532), which is an essential structural component of the cag PAI apparatus, plays an important role in the translocation of CagA into host epithelial cells. In addition to being located on the bacterial surface, CagT is also partially localized in the inner membrane, where it acts as a chaperone-like protein and promotes CagA translocation. However, CagT secretion was not detected by immunoprecipitation analysis of cell culture supernatants. Meanwhile, CagT was related to the introduction of IL-8 of the host cell. These results suggest that CagT is expressed on both the inner and outer bacterial membranes, where it serves as a unique type IV secretion system component that is involved in CagA secretion and cag PAI apparatus assembly.