• The Korean Journal of Pesticide Science
• /
• v.6 no.4
• /
• pp.279-286
• /
• 2002

To improve the growth inhibition activities and selectivities for quinclorac family, novel 3-substituted phenyl-5-(3,7-dichloro-8-quinolinyl)-1,2,4-oxadiazole derivatives as the substrate were synthesized and their the activities ($pI_{50}$) against shoot and root of rice plant (Oryza sativa L.) and barn-yard grass (Echinochloa crus-galli) were measured. And the quantitative structure-activity relationships (QSARs) between physicochemical parameters of the substitutents (R) on phenyl group and the activities ($pI_{50}$) were analyzed quantitatively. According to the SAR analyses, the substrates of planar conformation showed higher herbicidal activities against barnyard grass than rice plant. The activities against rice plant depend on the electronic effect (shoots: ${\sigma}_{opt.}=0.49$ & root: $R_{opt.}=-0.15$) of substituents, whereas the activities against shoots and roots of barnyard grass depend on hydrophobicity (${\pi}_{opt.}=0.37{\sim}2.40$). There were conditions of selective growth inhibition activity against barnyard grass when such a ortho-substituted electron donating substituents showing the hydrophobicity value, ${\pi}=2.40$ were introduced on the phenyl ring. The 2-tolyl substituent predicted from SAR equations was expected to have better growth inhibition activity and selectivity (${\Delta}pI_{50}=1.26$) for barnyard grass.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.1
• /
• pp.309-314
• /
• 2013

Aim: Brain tumors almost universally have fatal outcomes; new therapeutics are desperately needed and will only come from improved understandins of glioma biology. Methods: Exosomes are endosomally derived 30~100 nm membranous vesicles released from many cell types. Examples from GL26 cells were here purified using density gradient ultracentrifugation and monitored for effects on GL26 tumor growth in C57BL/6j mice (H-2b). Lactate dehydrogenase release assays were used to detect the cytotoxic activity of CD8+T and NK cells. Percentages of immune cells producing intracellular cytokines were analyzed by FACS. Results: In this study, exosomes from murine-derived GL26 cells significantly promoted in vivo tumor growth in GL26-bearing B6 mice. Then we further analyzed the effects of the GL26 cells-derived exosomes on immune cells including CD8+T, CD4+T and NK cells. Inhibition of CD8+T cell cytotoxic activity was demonstrated by CD8+T cell depletion assays in vivo and LDH release assays in vitro. The treatment of mice with exosomes also led to a reduction in the percentages of CD8+T cells in splenocytes as determined by FACS analysis. Key features of CD8+T cell activity were inhibited, including release of IFN-gamma and granzyme B. There were no effects of exosomes on CD4+T cells and NK cells. Conclusion: Based on our data, for the first time we demonstrated that exosomes from murine derived GL26 cells promote the tumor growth by inhibition of CD8+T cells in vivo and thus may be a potential therapeutic target.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.5
• /
• pp.396-401
• /
• 2006

The objective of this study was to investigate the antitumor activity of suspension cultures of tea callus cells grown in the presence of different concentrations of the growth regulator 2,4-dichlorophenoxy acetic acid (2,4-D) with or without light irradiation. The methanol and ethanol extracts of precipitated cells (MEP, EEP) exhibited stronger inhibitory effects on the growth of tumor cell lines than the water extract of precipitated cells (WEP) or the supernatant Compared to culture under dark conditions, exposure to light irradiation led to significantly higher antitumor activity. The MEP from light irradiated cells at $250{\mu}g/mL$ with 2.0mg/L 2,4-D displayed more than 64% growth inhibition of HEP-2 cells, whereas normal cells showed less than 25% growth inhibition. The some fractions of MEP obtained from Diaion HP-20 column chromatography displayed the majority of inhibitory activity against the HEP-2 cell line. These results show that 2,4-D, and light stimulated the synthesis of antitumor compounds.

• Microbiology and Biotechnology Letters
• /
• v.49 no.3
• /
• pp.374-383
• /
• 2021

Rhizoctonia solani is one of the major pathogens that cause sheath blight disease in rice. Sheath blight is one of the most difficult diseases to control. Biological control (with the use of rhizobacteria) is one of the ways to control this disease. Plant Growth Promoting Rhizobacteria (PGPR) is a rhizosphere bacterium that can be used to enhance plant growth. The composition of the rhizobacteria in organic and nonorganic soil is affected by the chemical characteristics of the soil - which influences plant physiology and root exudation patterns. This study aimed to obtain a species of rhizobacteria which shows PGPR activity, from organic and nonorganic rice fields and test their capability to suppress R. solani growth. Out of 23 isolates screened for PGPR activity, the following isolates showed high PGPR activity and were selected for in vitro antagonistic activity testing against R. solani: ISO6, ISO11, ISO15, ISN2, ISN3, and ISN7, The six isolates produced 43,42-75,23 ppm of IAA, possessed phosphorus solubilization capability, and chitinase-producing activity. ISO6 (54.88%) and ISN7 (83.33%) displayed high inhibition capacities against R. solani, in vitro. ISO6 and ISN7 inhibited the growth of R. solani lesions on rice leaves by 89% and 100% (without lesion), respectively, after 7 days of incubation. Analysis of their 16S rRNA sequences revealed that the ISO6 isolate was Citrobacter freundii and ISN7 isolate was Pseudomonas aeruginosa.

• Preventive Nutrition and Food Science
• /
• v.10 no.2
• /
• pp.167-171
• /
• 2005

The anticancer and apoptotic effect of chloroform extract from 24 month-fermented doenjang were investigated in AGS human gastric adenocarcinoma cells. The chloroform extract of 24 month-fermented doenjang inhibited the AGS gastric cancer cell growth in a dose-dependent manner. It has been confirmed by observing the cell distribution under inverted microscope. Approximately, 48 hour treatment of $100\;{\mu}g/mL$ doenjang extract inhibited AGS cancer cell growth by $76.7\%$, respectively. The growth inhibition may be caused by apoptosis of AGS cancer cells after 48 hour treatment of 24 month-fermented doenjang extract. It has been demonstrated by cell cycle arrest that revealed the shift from $G_2+M\;to\;G_0+G_1$ phase and the formation of apoptotic bodies. The fermentation period playa critical role in cell cycle arrest, in which 24 month-fermented doenjang extract was more effective than 12 month-fermented doenjang extract. The treatment of 24 month-fermented doenjang extract for 48 hours has induced intercellular Bax and decreased Bcl-2 level, indicating that it may regulate the expression level of Bax/Bcl-2 proteins. Thus, 24 month-fermented doenjang extract seems to have anticancer effect via cancer cell growth inhibition induced by apoptosis process.

• Food Science and Biotechnology
• /
• v.17 no.5
• /
• pp.1106-1109
• /
• 2008

The anti-Helicobacter pylori activity, cytotoxicity, and anti-inflammatory activity of white ginseng extract (WGE) were investigated in vitro in this study. The antimicrobial effects of WGE toward H. pylori strains 52 J99, SSI, and 51 were tested using the disk diffusion method. Among these H. pylori strains, H. pylori 52 was the most sensitive, having the largest inhibition zone (19 mm), followed by J99, SSI, and 51. The zone of inhibition due to WGE increased significantly with increasing dosage. The cytotoxicity of WGE toward the human cancer cell lines A-549 (human lung carcinoma), HEC-1-B (human endometrial adenocarcinoma), HeLa (human uterin adenocarcinoma), and SW-156 (human kidney carcinoma) was measured using the 3-(4,5-dimethylthizol-2-yl)-2,5-diphenylate-tetrazolium bromide (MTT) assay. WGE exhibited an inhibitory effect on cell growth at 2.0 mg/mL for all tumor cell lines. An analysis of anti-inflammatory activity using the RAW 264.7 cell line showed that the inhibition of nitric oxide (NO) production increased as the WGE content increased. These results demonstrate the potential of WGE to be used as a health-promoting substance.

• The Plant Pathology Journal
• /
• v.32 no.3
• /
• pp.209-215
• /
• 2016

In this study, the treatment of pistachio nuts by Bacillus subtilis UTBSP1, a promising isolate to degrade aflatoxin B1 (AFB1), caused to reduce the growth of Aspergillus flavus R5 and AFB1 content on pistachio nuts. Fluorescence probes revealed that the cell free supernatant fluid from UTBSP1 affects spore viability considerably. Using high-performance liquid chromatographic (HPLC) method, 10 fractions were separated and collected from methanol extract of cell free supernatant fluid. Two fractions showed inhibition zones against A. flavus. Mass spectrometric analysis of the both antifungal fractions revealed a high similarity between these anti-A. flavus compounds and cyclic-lipopeptides of surfactin, and fengycin families. Coproduction of surfactin and fengycin acted in a synergistic manner and consequently caused a strong antifungal activity against A. flavus R5. There was a positive significant correlation between the reduction of A. flavus growth and the reduction of AFB1 contamination on pistachio nut by UTBSP1. The results indicated that fengycin and surfactin-producing B. subtilis UTBSP1 can potentially reduce A. flavus growth and AFB1 content in pistachio nut.

• The Plant Pathology Journal
• /
• v.35 no.2
• /
• pp.137-148
• /
• 2019

In search of an effective biological control agent against the tomato pathogen Fusarium oxysporum f. sp. lycopersici, rhizospheric soil samples were collected from eight agro-ecological zones of Bangladesh. Among the bacteria isolated from soil, 24 isolates were randomly selected and evaluated for their antagonistic activity against F. oxysporum f. sp. lycopersici. The two promising antagonistic isolates were identified as Brevundimonas olei and Bacillus methylotrophicus based on morphological, biochemical and molecular characteristics. These two isolates were evaluated for their biocontrol activity and growth promotion of two tomato cultivars (cv. Pusa Rubi and Ratan) for two consecutive years. Treatment of Pusa Rubi and Ratan seeds with B. olei prior to inoculation of pathogen caused 44.99% and 41.91% disease inhibition respectively compared to the untreated but pathogen-inoculated control plants. However, treatment of Pusa Rubi and Ratan seeds with B. methylotrophicus caused 24.99% and 39.20% disease inhibition respectively. Furthermore, both the isolates enhanced the growth of tomato plants. The study revealed that these indigenous bacterial isolates can be used as an effective biocontrol agent against Fusarium wilt of tomato.

• Applied Biological Chemistry
• /
• v.35 no.3
• /
• pp.191-195
• /
• 1992

In order to elucidate the plant-microorganism relationship, we purified an ethylene-inducible, basic 30 KD endochitinase from bean leaves and studied its antifungal activity by a hyphal extension-inhibition assay. The purified chitinase was effective in the inhibition of hyphal growth of Aspergillus fumigatus, Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani, while microbial chitinases of Serratia marcescens and Streptomyces griceus, egg white lysozyme and papya protease didn't affect hyphal growth of the fungi. The chitinase degraded the cell walls of Micrococcus lysodeikticus, suggesting the lysozyme activity of the chitinase. We discussed the implication of the bifunctional chitinase/lysozyme activities of the protein with hydrolysis of chitin in the rapidly extending hyphae of the fungi.

• Microbiology and Biotechnology Letters
• /
• v.24 no.5
• /
• pp.624-629
• /
• 1996

The ethanol extracts from Angelica gigas Nakai and Angelica acutiloba Kitagawa were fractionated to diethyl ether and aqueous partitions. Both partitions had strong antimutagenic effect on the MNNG (N-methyl-N-nitro-N-nitrosoguanidine) by Ames mutagenicity test. Diethyl ether fractions exhibited the greatest antimutagenic effect suppressing the mutagenicity of MNNG with inhibition of 78-80%. The ethanol extracts from both species showed the inhibitory effect on the growth of several human cancer cell lines. Especially, the diethyl ether fraction from ethanol extracts was most effective on human hepatocellular carcinoma cells, inhibiting 90-95% of cell growth. However, the aqueous fractions had least inhibition activity on many cancer cells. There was little cytotoxicity on human normal liver cell by ethanol extracts. Diethyl ether fraction from Angelica gigas Nakai ethanol extract had cytotoxicity less than 20% on human normal liver cells, compared with that from Angelica acutiloba Kitagawa ethanol exract. The adding of 0.5 (g/l) of diethyl ether fractions of Angelica gigas Nakai or Angelica acutiloba Kitagawa increased immune activity by enhacing human B and T cells up to three to four times. It was proven that diethyl ether fraction (0.7 g/1) from Angelica gigas Nakai could control blood pressure by suppressing angiotensin converting enzyme activity up to 98%. From TLC, it was appeared that both of diethyl ether partitions had umbelliferon, known to one of active substances from Angelica gigas Nakai and Angelica acutiloba Kitagawa.