• Clean Technology
• /
• v.29 no.2
• /
• pp.135-144
• /
• 2023

Pseudomonas aeruginosa and Staphylococcus aureus are the two most frequently encountered pathogens responsible for chronic wound infections, often coexisting in such cases. These infections exhibit heightened virulence compared to single infections, leading to unfavorable patient outcomes. The interaction among microorganisms within polymicrobial infections has been shown to exacerbate disease progression. Polymicrobial infections, prevalent in various contexts such as the respiratory tract, wounds, and diabetic foot, typically involve diverse microorganisms, with Pseudomonas aeruginosa and Staphylococcus aureus being the most commonly identified pathogens. This study aimed to compare the growth patterns of bacteria under a concentration gradient of toxic chemicals, focusing on a Gram-negative strain of Pseudomonas aeruginosa and a Gram-positive strain of Staphylococcus aureus. The minimum inhibitory concentration (MIC), which signifies the concentration at which bacterial growth is inhibited, was determined by performing broth microdilution and assessing the bacteria's growth curves. The growth curves of both Pseudomonas aeruginosa and Staphylococcus aureus were confirmed, and the exponential growth phases were applied to calculate the doubling times of bacteria. The MIC value for each toxic chemical was determined through broth microdilution. These results allowed for the identification of disparities in growth rates between Gram-positive and Gram-negative bacteria, as well as differences in resistance to individual toxic substances. We expect that this approach has a strong potential for further development towards the innovative treatment of bacteria-associated infections.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.4
• /
• pp.430-440
• /
• 2023

The type three secretion system (T3SS) is a major virulence system of Pseudomonas aeruginosa (P. aeruginosa). The effector protein Exotoxin S (ExoS) produced by P. aeruginosa is secreted into the host cells via the T3SS. For the purpose of an experiment on inhibitors with regard to ExoS secretion, we developed a sandwich-type enzyme-linked immunosorbent assay (ELISA) system. Quercetin was selected because it has a prominent ExoS inhibition effect and also is known to have anti-inflammatory and antioxidant effects on mammalian cells. In this study, we investigated the effects of quercetin on the expression and secretion of ExoS using ELISA and Western blot analysis methods. The results showed that the secretion of ExoS was significantly decreased by 10 and 20 µM of quercetin. Also, popB, popD, pscF, and pcrV which are composed of the T3SS needle, are reduced by quercetin at the mRNA level. We also confirmed the inhibitory effect of quercetin on cytokines (IL-6, IL-1β, and IL-18) in P. aeruginosa-infected H292 cells by real-time polymerase chain reaction (PCR) and ELISA. Collectively, quercetin inhibits the secretion of ExoS by reducing both ExoS production and the expression of the needle protein of T3SS. Furthermore, these results suggest that quercetin has the potential to be used as an anti-toxic treatment for the inflammatory disease caused by P. aeruginosa infection.

• Korean Journal of Microbiology
• /
• v.46 no.1
• /
• pp.21-26
• /
• 2010

As the causative agent of Anthrax, Bacillus anthracis causes an acute fatal disease in herbivores such as cattle, sheep, and horses as well as humans. The therapeutics and prevention of anthrax currently available are based on antibiotics and the live attenuated vaccine strains, which may be problematic due to the emergency of antibiotic resistant strains or residual virulence in those vaccine strains. Therefore, it has been required to develop novel therapeutics and vaccines which are safer and applicable to humans. Recently, the development of the multivalent vaccine targeting both spores and vegetative cells of B. anthracis along with anthrax toxin has been reported. In our attempts to screen potential candidates for those multivalent vaccines, the whole genomic expression library of B. anthracis was constructed in this study. To the end, the partial digests of the genomic DNA from B. anthracis (ATCC 14578) with Sau3AI were ligated with the inducible pET30abc expression vectors, resulting in approximately $1{\times}10^5$ clones in E. coli BL21(DE3). The redundancy test by DNA nucleotide sequencing was performed for the randomly selected 111 clones and found 56 (50.5%) B. anthracis genes, 17 (15.3%) vector sequences, and 38 (34.2%) unknown genes with no sequence homology by BLAST. An inducible expression of the recombinant proteins was confirmed by Western blot. Interestingly, some clones could react with the antiserum against B. anthracis. These results imply that the whole genomic library constructed in this study can be applied for analyzing the immunomes of B. anthracis.

• Korean Journal of Cognitive Science
• /
• v.11 no.2
• /
• pp.37-51
• /
• 2000

The present study compared computer users target-selection response patterns when the targets were varied in terms of their relative location and distance from the current position of the cursor. In Experiment 1, where the mouse was used as an input device, the effects of different directions and distances of simple target(small rectangle) on target-selection response were investigated. The results of Experiment 1 can be summarized as follows: (1) Overshooting was more frequent than either undershooting or correct movement and (2) this tendency was more prominent when the targets were presented in the oblique direction or in farther location from the current cursor position. (3) Although the overshooting and undershooting were more frequent in the oblique direction, the degree of deviation was larger in horizontal and vertical direction. (4) Time spent in moving the mouse rather than that spent in planning, calibrating or clicking was found to be the most critical factor in determining total response time. In Experiment 2, effects of the font size and line-height of the target on target-selection response were compared with regard to two types of input devices(keyboard vs. mouse). The results are as follows: (1) Mouse generally yielded shorter target-selection time than keyboard. but this tendency was reversed when the targets were presented in horizontal and vertical directions. (2) In general, target-selection time was the longest in the condition of font size of 10 and line-height of 100%, and the shortest in the condition of font size of 12 and line-height of 150%. (3) When keyboard was used as the input device, target-selection time was shortest in the 150% line-height condition, whereas in the mouse condition, target-selection time tended to be increased as the line-height increased. which resulted in the significant interaction effect between input device and line-height. Finally, several issues relating to human-computer interaction were discussed based on the results of the present study.

• The Journal of the Petrological Society of Korea
• /
• v.9 no.2
• /
• pp.84-98
• /
• 2000

Daejeon-sa basalt in the Mt. Juwang area composed of 12 basalt flows alternate with 9 peperites and each basalt and peperite has the variety of thickness. Peperites yielded in Daejeon-sa basalt are mixed of basalt with reddish shale, of which textural type is globular peperite. Basalts yielded in Daejeon-sa basalt are massive basalt without vesicule, although sometimes vesicules are founded in upper within a flow unit. The basalt has mainly pseudomorph of olivine as phenocryst, and also plagioclase and clinopyroxene phenocryst. Matrix is mainly subophitic texture. The plotting result on the TAS diagram shows these basalts belong to the sub-alkaline, and it can be subdivided into calc-alkaline series on the basis of the diagram of Si02 vs. K20 and of alkali index vs. A1203 diagram. According to plots of wt.% oxides vs. wt.% MgO, abundances of A1203 and CaO increase with decreasing MgO while F ~ dOecre~ase . With decreasing MgO compatible elements decrease while incompatible elements increase. In spider diagram of MORB-normalized trace element patterns, HFS elements are nearly similiar with MORB, but LIL elements are enriched. Especially, contents of Ce, F: and Sm are enriched but Nb is depleted. In the chondrite-normalized REE patterns light REEs are enriched than heavy REEs. Tectomagmatic discrimination diagrams shows basalts in the study area are formed in the tectonomagmatic environment of subduction zone under continental margin. This result accord with characters of chemical composition mentioned above. Cr vs. Y diagram and CeM, vs. Ce diagram show that the primary magma of the basalts may formed by the about 15% partial melting of garnet-peridotite in the mantle wedge. After then, Daejeon-sa basalts may formed from evolved magma undergone mainly olivine fractional crystallization and contarnination of crustal materials before eruption.