• Title/Summary/Keyword: Reduced mechanism

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Alternate Prey: A Mechanism for Elimination of Bacterial Species by Protozoa (원생동물(原生動物)에 의한 세균류(細菌類)의 소거(消去)에 관(關)한 기작(機作))

  • Mallory, Larry M.;Yuk, Chang-Soo;Liang, Li-Nuo;Alexander, Martin
    • Korean Journal of Soil Science and Fertilizer
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    • v.16 no.4
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    • pp.358-367
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    • 1983
  • Antibiotic-resistant strains of Salmonella typhimurium and Klebsiella pneumoniae died readily after their addition to raw sewage, but they grew in sterilized sewage. The decline was not a result of antibiotic stresses, and because the bacteria were able to survive in large numbers for at least 15 days in solutions containing no organic nutrients, it was not a result of competition. Toxin production, bacteriophages, and Bdellovibrio did not cause the disappearance of the two bacterial species. A decline was also evident if the sewage was first passed through a $3-{\mu}m$ filter or treated with cycloheximide or cycloheximide plus nystatin, but protozoa developed under these conditions. Little or no decline occurred if the sewage was filtered and treated with the eucaryotic inhibitors before adding S. typhimurium or K. pneumoniae, and protozoa were not detected. S. typhimurium increased in abundance if cycloheximide, streptomycin, and erythromycin or large amounts of glucose were added to sewage. Tetrahymena thermophilus did not significantly reduce the population of S. typhimurium in buffer when the density of the bacterium was about $10^4/ml$. However, when more than $10^8$ Enterobacter agglomerans cells per ml were added to the buffer, T. thermophilus reduced the abundance of E. agglomerans and S. typhimurium to $10^6$ and 10/ml, respectively. The density of S. typhimurium was further decreased by a second increment of E. agglomerans cells. The disappearance of S. typhimurium and K. pneumoniae from sewage thus is the result of predation by protozoa. It is proposed that predators will eliminate a prey species from a natural environment when an alternate prey is present at concentrations above the threshold number for active feeing by the predator and when the rate of growth of the prey is less than the rate of predation.

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Protective Effects of Radiation-induced Blackberry Mutant Extract on Carbon Tetrachloride (CCl4)-induced Liver Injury in Sprague-Dawley Rats (방사선 돌연변이 블랙베리 추출물의 사염화탄소(Carbon Tetrachloride, CCl4) 투여에 의한 흰쥐의 간 손상에 대한 보호 효과)

  • Cho, Byoung Ok;Lee, Chang-Wook;So, Yangkang;Jin, Chang-Hyun;Yook, Hong-Sun;Byun, Myung-Woo;Jeong, Yong-Wook;Park, Jong Chun;Jeong, Il-Yun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.6
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    • pp.807-813
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    • 2014
  • The objective of the present study was to investigate the protective effects of anthocyanin-enriched extract from radiation-induced blackberry (Rubus fruticosus L.) mutant (${\gamma}$-B201) against carbon tetrachloride ($CCl_4$)-induced liver injury in Spargue-Dawley (SD) rats. The in vivo results show that ${\gamma}$-B201 attenuated the levels of serum aspartate aminotransferase, alanine aminotransferase, and liver lipid peroxidation in $CCl_4$-treated SD rats. Histopathological examination of rat livers showed that ${\gamma}$-B201 reduced the incidence of liver lesions induced by $CCl_4$. Moreover, ${\gamma}$-B201 prevented DNA damage in $CCl_4$-treated SD rats. Furthermore, administration of ${\gamma}$-B201 significantly increased the activity of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), in $CCl_4$-treated rat livers. In conclusion, the present study suggests that ${\gamma}$-B201 blackberry extract protects the liver from $CCl_4$-induced hepatic damage through an antioxidant mechanism. Therefore, ${\gamma}$-B201 blackberry may be functional food material for human health.

Antiadipogenic Effect of Korean Glasswort (Salicornia herbacea L.) Water Extract on 3T3-L1 Adipocytes (세포배양 모델을 통한 함초(Salicornia herbacea L.) 물 추출물의 항비만 효과 탐색)

  • Kim, Mi Joung;Jun, Hyun Young;Kim, Jung Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.6
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    • pp.814-821
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    • 2014
  • As a natural plant ingredients, glasswort (Salicornia herbacea L.) contains various physiological activities, mainly anti-oxidative and anti-diabetic activities. However, only a few studies have been carried out on its anti-adipogenic effect. This study investigated the anti-obesity effects of Salicornia herbacea L. on 3T3-L1 adipocytes. As adipogenesis of preadipocytes to adipocytes involves proliferation and differentiation of cells, we treated three concentrations (125, 250, and $500{\mu}g/mL$) of Salicornia herbacea L. water extracts (SLW) in both pre-processing and post-processing stages. When 3T3-L1 adipocytes were differentiated and dyed with Oil Red O, adipocytes size and the value of relative Oil Red O staining were reduced by all concentrations of SLW in post-processing stage. Following adipogenic differentiation, the concentration of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in the cell supernatant significantly increased upon treatment with $125{\mu}g/mL$ of SLW and further rose at concentrations of 250 and $500{\mu}g/mL$ during post-processing stage. There was no significant difference in glycerol production upon SLW treatment. Leptin production significantly decreased at all SLW concentrations during post-processing stage, whereas peroxisome proliferator activated receptor-${\gamma}$ (PPAR-${\gamma}$) and adiponectin secretions were significantly enhanced. Overall results showed that SLW might have an anti-adipogenic effect via enhancement of TNF-${\alpha}$ production, which causes dedifferentiation and inhibits lipid accumulations in adipocyte. Furthermore, SLW might prevent diabetes and cardiovascular disease, as it reduces leptin secretion and enhances production of both PPAR-${\gamma}$ and adiponectin. However, further research is needed to elucidate the exact mechanism and bioactive compounds of glasswort.

Repetition of Apoptosis Induced by Amiloride Derivatives in Human Umbilical Vein Endothelial Cells (제대정맥 내피세포에서 Amiloride 유도체에 의한 Apoptosis 반복)

  • Park, Kyu Chang;Park, Kyu Sang;Moon, Soo Jee
    • Clinical and Experimental Pediatrics
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    • v.46 no.1
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    • pp.56-66
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    • 2003
  • Purpose : Human umbilical vein endothelial cells(HUVECs) play an important role in regulating blood flow by releasing vasoactive substances. It has been reported that endothelial impairment and dysfunction might be a primary cause of placental vascular disease, which is manifested clinically as preeclampsia in mother and intrauterine growth restriction in fetus. Furthermore, the frequency of apoptotic changes is increased in umbilical and placental tissues from growth-restricted pregnancies. However, the various mechanisms of umbilical endothelial cell apoptosis have not been broadly proposed. We investigate the effects of amiloride derivatives on apoptotic death of HUVECs and identify their ionic mechanism. Methods : HUVECs were purchased from Clonetics, and cultured on endothelial cell growth medium. MTT assay and flow cytometry were used for assessing cytotoxic effect and confirming the apoptosis. Changes in intracellular ion concentrations were measured with specific fluorescent dyes and fluorescence imaging analysis system. Results : Amiloride derivatives elicited cytotoxic effects on HUVECs with dose-dependent manners and the rank order of potency is HMA($IC_{50}\;11.2{\mu}M$), MIA>EIPA>>amiloride. HMA-induced cytotoxicity is dependent on extra- and intracellular pH, that is, increase extra- and intracellular pH augmented the cytotoxic effects of HMA. HMA dose-dependently reduced intracellular major ions, such as $K^+$ and $Cl^-$. Interestingly, the depletion of intracellular ions induced by HMA was also significantly enhanced at alkaline extracellular pH. Conclusion : Amiloride derivatives induce apoptosis of HUVECs with dose and pH dependent manners. They reduce intracellular $K^+$ and $Cl^-$ concentration, which is also extracellular pH dependent.

Effects of Green Tea on Hepatic Antioxidative Defense System and Muscle Fatigue Recovery in Rat after Aerobic Exercise (녹차가 유산소 운동 후 흰쥐 간조직의 항산화 작용 및 근피로 회복에 미치는 영향)

  • 김미지;이순재
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.6
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    • pp.1058-1064
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    • 2002
  • The purpose of this study was to investigate the effects of green tea on hepatic antioxidative defense system and recovery of muscle fatigue in rat after aerobic exercise. Male Sprague-Dawley rats weighing 150$\pm$ 10 g were randomly assigned to one normal (N) group and aerobic exercise training groups. Exercise training groups were classified into two groups: training (T) group and green tea (TG) group which were supplemented the distilled water and green tea extracts by dringking water during experimental periods, respectively. The experimental rats in exercise training groups (T and TG) ran on a treadmill 30 min/day at a speed of 28 m/min (7% incline) 5 days/week or were cage confined (Normal group) for 4 weeks. And rats were sacrificed with an overdose of pentobarbital injection just after running. Hepatic xanthine oxidase (XOD) activities were not significantly different among three groups. The activity of superoxide dismutase (SOD) in T group was no significant difference from N group, but those of TG groups were significantly increased, compared with that of T group. Hepatic glutathione peroxidase (GSHpx) activites of TG groups showed a similar tendency to that of normal group, but it was increased to 20% in TG group, compared with normal group. The reduced glutathione (GSH) contents in liver was not significantly different from that of any three group. The oxidized glutathione (GSSG) contents in T group was increased to 69%, compared with the normal group, but TG group significantly decreased, compared with the T group. The ratio of GSH/GSSG in liver of T group was lower than that of normal group, but those of TG group was a similar tendency to that of normal group. Contents of thiobarbituric acid reactive substance(TBARS) in T group was increased to 52%, compared with that of normal group but those of TG group were recovered the normal level. Contents of hepatic glycogen in T group were decreased to 23% compared with those of normal group, while that of TG group was the same as normal levels. The contents of serum lactic acid in T group were increased to 261%, compared with normal group, but those of TG group maintained the normal level by green tea supplementations. In conclusion, the effects of green tea in exercise training rats would appear to reduce peroxidation of tissue as an antioxidative defense mechanism and promote recovery of muscle fatigue.

Sorghum Extract Lowers Lymphatic Absorption of Trans Fat and Cholesterol in Rats (흰쥐에서 수수추출물이 트랜스지방산이 함유된 지방과 콜레스테롤의 흡수에 미치는 영향)

  • Kim, Juyeon;Noh, Sang Kyu;Woo, Koan-Sik;Seo, Myung-Chul
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.6
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    • pp.783-788
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    • 2016
  • Excessive intake of trans fats is a risk factor for cardiovascular diseases. Previously, we showed that green tea extract lowers intestinal absorption of cholesterol and elaidic acid in rats. This study was conducted to investigate a possible role for sorghum extract on lymphatic absorption of trans fat and cholesterol in rats. Adult male rats with lymph cannulae were infused at a rate of 3.0 mL/h for 8 h via a duodenal catheter with a lipid emulsion containing $146.4{\mu}mol$ of trielaidin, $36.8{\mu}mol$ of trilinoelaidin, $452.0{\mu}mol$ of triolein, $1.0{\mu}Ci$ cholesterol labeled with $^{14}C$ ($^{14}C-cholesterol$), $20.7{\mu}mol$ of cholesterol, and $396.0{\mu}mol$ of Na-taurocholate without or with 100.0 mg of sorghum extract in phosphate-buffered saline buffer (pH 6.4). Lymph was collected hourly for 8 h. No significant difference was noted in lymph flow. However, the lymphatic absorption of elaidic acid and linoelaidic acid for 8 h was significantly lower in rats infused with sorghum extract than in those infused with no sorghum extract. Further, lymphatic absorption of $^{14}C-cholesterol$ was reduced by sorghum extract, which was observed previously. These data indicate that sorghum extract has an inhibitory effect on the intestinal absorption of trans fat and cholesterol. The mechanism(s) by which sorghum extract lowers intestinal absorption of trans fat warrants further study.

In Vitro Hepatoprotective Effects of Fermented Curcuma longa L. by Aspergillus oryzae against Alcohol-Induced Oxidative Stress (알코올성 산화적 손상에 대한 발효울금의 간세포 보호 효과)

  • Sung, Heami;Lee, Yoo-Hyun;Jun, Woojin
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.6
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    • pp.812-818
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    • 2016
  • Protective effects of fermented Curcuma longa L. (CL) against alcoholic liver damage were investigated in HepG2/2E1 cells. Fermented CL was extracted by cold water (FCC), hot water, 80% ethanol, and methanol. Of the four extracts, the strongest hepatoprotective effect against ethanol-induced oxidative stress was observed in FCC. Pretreatment with FCC also reduced intracellular reactive oxygen species formation compared to ethanol-alone treated cells. FCC also enhanced catalase, glutathione-S-transferase, glutathione reductase, glutathione peroxidase, and superoxide dismutase, and non-enzymatic antioxidative activities such as glutathione compared to alcohol-treated HepG2/2E1 cells. Our findings suggest that FCC might be considered as a useful agent in the prevention of liver damage induced by oxidative stress by increasing the antioxidant defense mechanism.

Effects of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$ ) on Freund's Complete Adjuvant-induced Arthritic Rats (Adjuvant 유발 관절염 랫트에 대한 삼기음의 효과)

  • Choi, Eun-Sill;Jang, Hong-Gyu;Kwon, O-Gon;Woo, Chang-Hoon;An, Hee-Duk
    • Journal of Korean Medicine Rehabilitation
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    • v.23 no.3
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    • pp.1-14
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    • 2013
  • Objectives The object of this study was to observe the favorable anti-arthritic effects of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) on Freund's complete adjuvant (FCA)-induced arthritic Wistar rats. Methods Rheumatoid arthritis was induced by intradermal injection of FCA, and 300, 150 or 750 mg/kg of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) were orally administered once a day for 14 days from 14 days after FCA treatments, and 15 mg/kg of dexamethasone was intraperitoneally administered as reference drug in this experiment. All rats were sacrificed at 14 days after continuous oral treatment of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) or intraperitoneal administration of dexamethasone, and changes on the body weight, knee circumferences, gross arthritis score, inflammatory tissue prostaglandin (PG) $E_2$ levels were monitored with cartilage collagen components and glucosaminoglycans compositions - chondroitin sulphate, heparan sulphate and hyaluronic acid in the present study. Results As results of FCA treatment, classic rheumatoid arthritis featuring dramatical decreases on the body weights, cartilage collagen contents and bone glucosaminoglycans-chondroitin sulphate, heparan sulphate and hyaluronic acid contents, with increases on the knee circumferences, gross arthritis scores and inflammatory tissue $PGE_2$ levels. However, these changes from FCA-induced rheumatoid arthritis were clearly reduced by treatment of dexamethasone and both two different dosages of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 and 150 mg/kg in the present study. Although FCA-induced arthritis were more favorably inhibited by treatment of dexamethasone 15 mg/kg as compared with Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg, marked decreases of body weights were detected in dexamethasone 15 mg/kg treated rats, and Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg showed similar preserve effects on the cartilage glucosaminoglycan compositions in this study. Conclusions The results obtained in this study suggest that over 300 and 150 mg/kg of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) showed favorable anti-arthritic effects on the FCA-induced arthritis mediated by suppression of $PGE_2$, a inflammatory mediator. However, detail mechanism studies should be conduced in future with the screening of the biological active compounds in this herb. Although overall anti-inflammatory effects Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg were lowered than those of dexamethasone 15 mg/kg treated rats, Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg treated rats showed similar preserve effects on the cartilage glucosaminoglycan compositions in this experiment.

Particle Size Analysis of Nano-sized Talc Prepared by Mechanical Milling Using High-energy Ball Mill (고에너지 볼 밀을 이용한 나노 활석의 형성 및 입도 분석)

  • Kim, Jin Woo;Lee, Bum Han;Kim, Jin Cheul;Kim, Hyun Na
    • Journal of the Mineralogical Society of Korea
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    • v.31 no.1
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    • pp.47-55
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    • 2018
  • Talc, hydrous magnesium phyllosilicate, is one of the most popular industrial minerals due to their chemical stability and adsorptivity. While micro-sized talc has long been used as a filler and coating, nano-sized talc recently is attracting attention as additives for improving the stability of nanocomposites. In this study, we produced the nano-sized talc powder by mechanical method using high energy ball mill and investigated the changes in particle size and crystallinity with increasing milling time up to 720 minutes. X-ray diffraction results show that the peak width of talc gradually as the milling proceeded, and after 720 minutes of pulverization, the talc showed an amorphous-like X-ray diffraction pattern. Lase diffraction particle size analysis presents that particle size of talc which was ${\sim}12{\mu}m$ decreased to ${\sim}0.45{\mu}m$ as the milling progressed, but no significant reduction of particle size was observed even after grinding for 120 minutes or more. BET specific surface area, however, steadily increases up to the milling time of 720 minutes, indicating that the particle size and morphology change steadily as the milling progressed. Scanning electron microscope and transmission electron microscope images shows that layered particles of about 100 to 300 nm was aggregated as micro-sized particles after pulverization for 720 minutes. As the grinding time increases, the particle size and morphology of talc continuously change, but the nano-sized talc particles form micro sized agglomerates. These results suggest that there is a critical size along the a, b axes in which the size of plates is reduced even though the grinding proceeds, and the reduction of plate thickness along the c axis leads the increase in specific surface area with further grinding. This study could enhance the understanding of the mechanism of the formation of nano-sized talc by mechanical grinding.

Evaluation on Removal Efficiency of Methylene Blue Using Nano-ZnO/Laponite/PVA Photocatalyzed Adsorption Ball (Nano-ZnO/Laponite/PVA 광촉매 흡착볼의 메틸렌블루 제거효율 평가)

  • Oh, Ju Hyun;Ahn, Hosang;Jang, Dae Gyu;Ahn, Chang Hyuk;Lee, Saeromi;Joo, Jin Chul
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.9
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    • pp.636-642
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    • 2013
  • In order to overcome drawbacks (i.e., filtration and recovery) of conventional powder type photocatalysts, nano-ZnO/Laponite/PVA (ZLP) photocatalyzed adsorption balls were developed by using in situ mixing of nanoscale ZnO as a photocatalyst, and Laponite as both adsorbent and supporting media in deionized water, followed by the poly vinyl alcohol polymerization with boric acid. The optimum mixing ratio of nano-ZnO:Laponite:PVA:deionized water was found to be 3:1:1:16 (by weight), and the mesh and film produced by PVA polymerization with boric acid might inhibit both swelling of Laponite and detachment of nanoscale ZnO from ZLP balls. Drying ZLP balls with microwave (600 watt) was found to produce ZLP balls with stable structure in water, and various sizes (55~500 ${\mu}m$) of pore were found to be distributed based on SEM and TEM results. In the initial period of reaction (i. e., 40 min), adsorption through ionic interaction between methylene blue and Laponite was the main removal mechanism. After the saturation of methylene blue to available adsorption sites for Laponite, the photocatalytic degradation of methylene blue occurred. The effective removal of methylene blue was attributed to adsorption and photocatalytic degradation. Based on the results from this study, synthesized ZLP photocatalyzed adsorption balls were expected to remove recalcitrant organic compounds effectively through both adsorption and photocatalytic degradation, and the risks of environmental receptors caused by detachment of nanoscale photocatalysts can be reduced.