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

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.143-154
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• 1990

Observations were made on the differences of cell-mediated responses in mice of three infectiorl groups di여erently scheduled in their severity with pathogenic Acanthamoeba culbertseni. Infections were done by dropping $5{\;}{\mu}l$ saline suspension containing $3{\times}10^3,{\;}1{\times}10^4,{\;}or{\;}1{\times}10^5$ trophosoites, respectively. Amoebae were cultured anenically in CGV medium and inoculated into the right nasal cavity of CSH/HeJ mice aging around 6∼8 weeks, under the anesthesia by intraperitoneal injection of secobarbital. Delayed type hypersensitivity (DTH) responses in footpad and blastogenlc responses of mouse spleen cells using ($^3H$)-thymidine and the serum antibody titer were measured up to day 14 after infection, and natural killer cell activities were measured up to day, i after infection. The results obtained in this study were as follows: 1. The mice infected with $3{\times}10^3$ trophosoites showed mortality rate of 17%, and 345 in the mice infected with $1{\times}10^4$ trophozoites and 65% with $1{\times}10^5$ trophozoites. 2. In regard to DTH responses in all experimental groups, the level increased on day 7 and declined on day 14 after infection, but their differences could not be noted between infected and control groups. 3. The blastogenic responses of splenocytes treated with amoeba Iysates and lipopolysaccharides (LPS) showed no difference from the control group. The blastogenic responses of splenocytes treated with concanavalin A were declined significantly in the experimental group as compared with the control group, but the blastogenic responses of splenocytes treated with polyinosinic acid were not different from the control group. There was also no difference among three infected groups. 4. The cytotoxic activity of the natural killer cells was activated on day 1 after infection and declined to the level of control group on day 2 in all experimental groups. On day 5 after infection, the natural killer cell cytotoxicity was significantly suppressed as compared with the control groups. 5. The serum antibody titers of the infected mice increased after day 7, but there was no statistical difference between the three infected groups. In summary of the results, there was no difference in cell-mediated immune responses of three experimental groups scheduled with different infection intensities. But there was a significant difference in cell$.$mediated immune responses between infected and control mice. It is considered that cell-mediated immune responses should be involved in murine model infected with A. culbertsoni.

• Journal of Food Hygiene and Safety
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• v.8 no.1
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• pp.37-53
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• 1993

F. moniliforme MRC 826, a common fungal contaminant of com, has been known to produce a group of mycotoxins, the fumonisins. By thin layer chromatography, fumonisin $B_{1}$ was detected in the F. moniliforme MRC 826 com culture material(CM) extracts. This study was performed to compare the toxicity and carcinogenicity of F. moniliforme MRC 826 CM with those of aflatoxin $B_1(AFB_1)$ in rats. The toxicity was tested over a period of 7 days in ten female Sprague-Dawley (SD) rats. Treatment group were fed a 1 : 1 mixture(wt/wt) of ground CM and basal diet in powder form, while other negative control group were given basal diet alone. The principal pathological changes in rats treated with 50% CM were hepatocellular hydropic degeneration and renal tubular necrosis. The cancer-promoting activity of CM was evaluated in the rat liver diethylnitrosamine-two thirds partial hepatectomy(DEN-PH) model for carcinogenesis. 70 male SO rats(ca. 170 g) were randomized into 5 groups. Group I served as the positive controls and received the basal diet containing 2 ppm $AFB_{1}$ group 2 received 5% CM, group 3 received 2.5% CM, group 4 received 5% normal com and group 5 received 2.5% normal com. 5% treated group showed cancer promoting activity in rat liver using DEN as initiator and the induction of glutathione S-transferase placental form positive foci as an end point after 6 weeks of promotion.

• Clinical and Experimental Pediatrics
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• v.52 no.5
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• pp.594-602
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• 2009

Purpose : Transforming growth factor (TGF)-${\beta}1$ reportedly increases neuronal survival by inhibiting the induction of inducible nitric oxide synthase (NOS) in astrocytes and protecting neurons after excitotoxic injury. However, the neuroprotective mechanism of $TGF-{\beta}1$ on hypoxic-ischemic (HI) brain injury in neonatal rats is not clear. The aim of this study was to determine whether $TGF-{\beta}1$ has neuroprotective effects via a NO-mediated mechanism and N-methyl-D-aspartate (NMDA) receptor modulation on perinatal HI brain injury. Methods : Cortical cells were cultured using 19-day-pregnant Sprague-Dawley (SD) rats treated with $TGF-{\beta}1$ (1, 5, or 10 ng/mL) and incubated in a 1% O2 incubator for hypoxia. Seven-day-old SD rat pups were subjected to left carotid occlusion followed by 2 h of hypoxic exposure (7.5% $O_2$). $TGF-{\beta}1$ (0.5 ng/kg) was administered intracerebrally to the rats 30 min before HI brain injury. The expressions of NOS and NMDA receptors were measured. Results : In the in vitro model, the expressions of endothelial NOS (eNOS) and neuronal NOS (nNOS) increased in the hypoxic group and decreased in the 1 ng/mL $TGF-{\beta}1-treated$ group. In the in vivo model, the expression of inducible NOS (iNOS) decreased in the hypoxia group and increased in the $TGF-{\beta}1$-treated group. The expressions of eNOS and nNOS were reversed compared with the expression of iNOS. The expressions of all NMDA receptor subunits decreased in hypoxia group and increased in the $TGF-{\beta}1$-treated group except NR2C. Conclusion : The administration of $TGF-{\beta}1$ could significantly protect against perinatal HI brain injury via some parts of the NO-mediated or excitotoxic mechanism.

• Economic and Environmental Geology
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• v.50 no.3
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• pp.215-224
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• 2017

Arsenic (As) is known to be the most toxic element and frequently detected in groundwater environment. Inorganic As exists as arsenite [As(III)] and arsenate [As(V)] in reduced and oxidized environments, respectively. It has been reported that the toxicity of arsenite is much higher than that of arsenate and furthermore arsenite shows relatively higher mobility in aqueous environments. For this reason, there have been numerous researches on the process for oxidation of arsenite to arsenate to reduce the toxicity of arsenic. In particular, photooxidation has been considered to be simple, economical, and efficient to attain such goal. This study was conducted to evaluate the applicability of naturally-occurring goethite as a photocatalyst to substitute for $TiO_2$ which has been mostly used in the photooxidation processes so far. In addition, the effects of several factors on the overall performance of arsenite photocatalytic oxidation process were evaluated. The results show that the efficiency of the process was affected by total concentration of dissolved cations rather than by the kind of those cations and also the relatively higher pH conditions seemed to be more favorable to the process. In the case of coexistence of arsenite and arsenate, the removal tendency by adsorption onto goethite appeared to be different between arsenite and arsenate due to their different affinities with goethite, but any effect on the photocatalytic oxidation of arsenite was not observed. In terms of effect of humic acid on the process, it is likely that the higher concentration of humic acid reduced the overall performance of the arsenite photocatalytic oxidation as a result of competing interaction of activated oxygen species, such as hydroxyl and superoxide radicals, with arsenite and humic acid. In addition, it is revealed that the injection of oxygen gas improved the process because oxygen contributes to arsenite oxidation as an electron acceptor. Based on the results of the study, consequently, the photocatalytic oxidation of aqueous arsenite using goethite seems to be greatly feasible with the optimization of process.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.621-629
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• 2016

Recently, the researches on quantitative structure activity relationship (QSAR) for describing toxicities or activities of chemicals based on chemical structural characteristics have been widely carried out in order to estimate the toxicity of chemicals in multiuse facilities. Because the toxicity of chemicals are explained by various kinds of molecular descriptors, an important step for QSAR model development is how to select significant molecular descriptors. This research proposes a statistical selection of significant molecular descriptors and a new QSAR model based on partial least square (PLS). The proposed QSAR model is applied to estimate the logarithm of partition coefficients (log P) of 130 polychlorinated biphenyls (PCBs) and lethal concentration ($LC_{50}$) of 14 PCBs, where the prediction accuracies of the proposed QSAR model are compared to a conventional QSAR model provided by OECD QSAR toolbox. For the selection of significant molecular descriptors that have high correlation with molecular descriptors and activity information of the chemicals of interest, correlation coefficient (r) and variable importance of projection (VIP) are applied and then PLS model of the selected molecular descriptors and activity information is used to predict toxicities and activity information of chemicals. In the prediction results of coefficient of regression ($R^2$) and prediction residual error sum of square (PRESS), the proposed QSAR model showed improved prediction performances of log P and $LC_{50}$ by 26% and 91% than the conventional QSAR model, respectively. The proposed QSAR method based on computational toxicology can improve the prediction performance of the toxicities and the activity information of chemicals, which can contribute to the health and environmental risk assessment of toxic chemicals.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.484-497
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• 2024

Neonicotinoid pesticides, widely used worldwide as potent insecticides, have been found to have detrimental effects on the environment and living organisms due to their persistent residues. This study aimed to investigate the neonicotinoid pesticides, imidacloprid, and clothianidin, focusing on their impact on honey bee toxicity and foliar residue levels. Alfalfa was selected as control crop while bell peppers, and cucumbers were chosen as representative application crops, respectively. The investigation involved comparing the toxicity and foliar residue levels resulting from soil and foliar treatments, with a focus on identifying potential shortcomings in conventional foliar residue toxicity testing methods. Imidacloprid and clothianidin were applied to crops or soil at recommended rates and through irrigation. The honey bee mortality rate (RT₂₅) over time was determined, and pesticide residues on leaves were quantified using High-Performance Liquid Chromatography (HPLC). The results revealed that foliar treatment with imidacloprid on alfalfa resulted in an RT₂₅ of less than 1 day, with residues ranging from 1.07 to 19.27 mg/kg. In contrast, application on bell peppers showed RT₂₅ within 9 days, with residues ranging from 1.00 to 45.10 mg/kg. Clothianidin foliar treatment displayed RT₂₅ within 10 days on alfalfa, with residues between 0.61 and 2.57 mg/kg. On bell peppers, RT₂₅ was within 28 days, with residues ranging from 0.13 to 2.85 mg/kg. Soil treatment with imidacloprid and clothianidin in alfalfa exhibited minimal impact on honey bees and residues of 0.05 to 0.37 mg/kg. However, in applied crops, imidacloprid showed RT₂₅ within 28 days and residues ranging from 4.47 to 130.43 mg/kg, while clothianidin exhibited RT₂₅ within 35 days and residues between 5.96 and 42.32 mg/kg. In conclusion, when comparing honey bee toxicity and foliar residues among crops, application crops had a more significant impact on honey bee mortality and higher residue levels compared to control crops. Moreover, soil treatment for application crops resulted in higher RT₂₅ and residue levels compared to foliar treatment. Therefore, to ensure pesticide safety and environmental sustainability, diverse research approaches considering different crops and application methods are necessary for the safety assessment of imidacloprid and clothianidin.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.185-192
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• 1990

The present work was undertaken to investigate the protective effect of diallyl disulfide on the bromobenzene toxicity in mice. It was observed that the aniline hydroxylase and epoxide hydrolase activities were not changed by the treatment of diallyl disulfide for 5 days. But glutathione S-transferase activity was significantly increased. A striking enhancement of serum alanine aminotransferase activity and hepatic lipid peroxide content after bromobenzene administration was markedly decreased by diallyl disulfide pretreatment. These results indicate that the inducing effects of diallyl disulfide on the bromobenzene intermediate detoxifying enzyme such as glutathione S-transferase are believed to be a possible protective mechanism for the bromobenzene toxicity in mice.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.217-221
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• 2007

In order to determine the effects of ginseng powder on the antioxidant enzyme activities of hepatotoxicity in $benzo({\alpha})pyrene[B({\alpha})P]-treated$ mice, the mice were divided into 5 groups. Ginseng powder was injected intraperitoneally once a day for 5 successive days, followed by the administration of $B({\alpha})P$ treatment on the fifth day. We also evaluated the relationship existing between lipid peroxidation and ginseng powder on oxidative stress. The increased activities of superoxide dismutase, catalase, and glutathione peroxidase observed following $B({\alpha})P-treatment$ were reduced as the result of ginseng powder treatment. Whereas, the glutathione content and glutathione S-transferase activity depleted by $B({\alpha})P$ were increased significantly, but the $B({\alpha})P-associated$ elevation of cytochrome P-450 activities and lipid peroxide content were reduced as the result of ginseng powder treatment. These results indicate that ginseng powder may exert a protective effect against $B({\alpha})P-induced$ hepatotoxicity in mice.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.11-15
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• 2006

The biological activities of extracts from the fruit, stem, and leaf of Hovenia dulcis were examined. In the batch mode of operation, the fruit, stem, and leaf of Hovenia dulcis were extracted with hot water for 10 hr. The fruit extract of Hovenia dulcis gave the highest activity for decreasing alcohol concentration which was 138% of control. The equilibrium between bioactive compound in the fruit (size : 4 mm) and hot water solution was reached within 6 hr and the recovery was 95% by three-times extraction. The fruit extract of Hovenia dulcis showed significant alcohol decrease in blood and hepatoprotective activity against $CCl_4$-toxicity in rat. The fruit extract significantly inhibited the elevation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) levels.