• Research in Plant Disease
• /
• v.23 no.2
• /
• pp.159-167
• /
• 2017

This study was conducted to evaluate the control efficacy of the organic farming materials on cucumber scab caused by Cladosporium cucumerinum PT1 (KACC 48094). The antifungal activities in vitro as well as the suppressive effect of 43 organic farming materials on the spore germination and germ tube growth by inoculating spore suspension on cucumber seedlings in vivo were investigated. Thirteen organic farming materials inhibited the mycelial growth of C. cucumerinum and nine of these were microbial agents. In the screening using cucumber seedlings, six organic farming materials were very effective with control efficacy value of 90%. Among them, Bacillus amyloliquefaciens M27 provided suppressive effect on both mycelial growth and spore germination against cucumber scab. Finally, nine organic farming materials were selected to test the protective and curative effects, and all chosen organic farming materials significantly suppressed disease incidence when applied in the preventive action, in comparison with the curative action. Especially, Bordeaux mixture I and III gave excellent protective control efficacy with control values of 96.7% and 73.3%, respectively, whereas its curative control effect was significant low. Among these, only Thymus quinquecostatus+Sophora extract showed curative activity, although the control value was as low as 50%. This study suggests that cucumber scab can be controlled by some organic farming materials in the farmhouses under comparatively cold and wet condition and protective treatment is more important and efficient.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.2
• /
• pp.312-318
• /
• 1999

Volatile compounds in salt fermented anchovy on the market were analyzed by vacuum simulta neous distillation solvent extraction/gas chromatography/mass spectrometry/olfactometry(V SDE/ GC/MS/O) and aroma extract dilution anlaysis(AEDA). Predominant odorants(Log3FD$\geq$8) in sample were ethyl methylbutanoate(candy like/sweet) and 2 ethyl 3,5 dimethylpyrazine(nutty/baked potato like). Besides these compounds, 6 odorants such as ethyl 3 methylbutanoate(sweet/floral/ candy like), 3 methylbutanal(dark chocolate like), (Z) 4 heptenal(rancid/fish like), (methylthio) propanal(soy sauce /baked potato like), (E,Z) 2,6 nonadienal(melon /cucumber like) and (E,E) 2,4 decadienal(fatty/cooked soybean like) were potent in odor value of salt fermented anchovy. Seven amino acids having high taste value in sample were glutamic acid, aspartic acid(sour and umami taste), lysine, alanine(sweet), histidine, valine, and methionine(bitter).

• Microbiology and Biotechnology Letters
• /
• v.10 no.3
• /
• pp.197-203
• /
• 1982

The protopectinase from the culture extract of a Verticillium sp. was purified about 1000 fold by ammonium sulfate fractionation, DEAE-Sephadex treatment and Sephadex G-75 column chromatography. The purified enzyme was homogeneous on electrophoresis and its molecular weight was estimated to be 38000 by Andrew's gel filtration, method. The enzyme was almost stable under the temperature of 4$0^{\circ}C$ and within the pH range of 3-5. Its optimum pH and temperature were 4 and 4$0^{\circ}C$, respectively. The activity was markedly inhibited by galacturonic acid. The purified enzyme was able to macerate various kinds of plant tissues, such as radish, cucumber, onion, carrot, and potato. It also reduced the viscosity of pectin solution more rapidly than that of pectic acid solution and showed no lyase or CMCase activity.

• Proceedings of the Korean Society of Life Science Conference
• /
• 2005.04a
• /
• pp.177-177
• /
• 2005

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.4
• /
• pp.401-408
• /
• 2016

The present study described the isolation of 2-methylbutyric acid (2-MBA) produced from Bacillus pumilus L1, to subsequently investigate its nematicidal activity for the control of the root-knot nematode. The results showed that 2-MBA could be purified by chromatographic techniques and was identified using nuclear magnetic resonance and liquid chromatography-mass spectrometry. Crude extract and partially purified compounds had a significant effect on the inhibition of egg hatchability and second-stage juvenile (J2) mortality. A dose-dependent effect of 2-MBA was observed for J2 mortality and egg hatchability. Egg hatchability was 69.2%, 59.9%, 32.7%, and 0.0% at 125, 250, 500, and $1000{\mu}g\;mL^{-1}$ of 2-MBA after 4 d of incubation, respectively. Meanwhile, J2 mortality was in the range of 24.4%-100.0% after 2 d of incubation, depending on the concentrations of 2-MBA used. A pot experiment also demonstrated that treatment of B. pumilus L1 culture caused a significant reduction in the number of galls, egg masses, and J2 population than that of the tap water (TW) control. However, as the B. pumilus L1 culture concentration was decreased, the efficacy of nematode control by treatment of B. pumilus L1 culture was reduced compared to that of TW. B. pumilus L1 inoculation at different concentrations also promoted cucumber plant growth. Therefore, our study demonstrated the potential of 2-MBA from B. pumilus L1 as a biocontrol agent against the root-knot nematode and a plant growth promoter for cucumber plants.

• Research in Plant Disease
• /
• v.10 no.1
• /
• pp.53-57
• /
• 2004

Cucumber green mottle mosaic virus (CGMMV) was a major pathogen of watermelon and had affected seriously to watermelon production in Korea. Rapid and sensitive detection method of CGMMV associated with bottle gourd (Lagenafia siceraria) seeds was developed by using RT-PCR in this study. A pair of primeri Wmfl and Wmrl, specific for CGMMV was designed from coat protein gene sequences of CGMMV-W and used for amplifying 420 bp product in RT-PCR. To simplify the virus extraction procedure and reduce an inhibitor from the extract for the RT-PCR, some methods using ethanol precipitation, double filtration, polyethylene glycol precipitation and phenol/chloroform/isoamyl alcohol extraction procedure were compared and the phenol/chloroform/isoamyl alcohol extraction procedure was selected by its enhanced sensitivity. This detection method using the selected extraction step and the primers for RT-PCR could reliably detect an infected level of one CGMMV-infested seed in 1,000 seeds. This rapid and sensitive RT-PCR assay provides auseful tool for the specific detection of CGMMV in bottle gourd seed samples containing high levels of back-ground inhibitors.

• Fisheries and Aquatic Sciences
• /
• v.24 no.8
• /
• pp.284-295
• /
• 2021

Red sea cucumber Stichopus japonicus is an invertebrate animal inhabiting in coasts of Korea, China, and Japan. They are traditionally used for food and medicine and well known for their distinctive biologically and pharmacologically important compounds. We investigated the effect of amyloglucosidase (AMG) enzymatic extracts of S. japonicus (AESJ) on the proliferation and cytokine secretion of murine splenocytes stimulated with concanavalin A (Con A). AESJ enhanced the proliferation of splenocytes and the production of IL-2 (Th1 cytokine), IL-1β (Th1 promoting cytokine), and IL-4, IL-10 (Th2 type cytokines) when treated alone. However, under Con A stimulation, AESJ suppressed the proliferation of splenocytes, attenuated the secretion of IL-2, IL-4, IL-10, and enhanced IL-1β secretion. These results suggest that AESJ exhibits immunomodulatory effect by moderating the proliferation of splenocytes and the secretion of IL-2, IL-1β, IL-4, and IL-10 differently depending on the absence and presence of Con A stimulation. These data evidence the immunomodulatory potential of AESJ, which can be further developed into a functional food mediating homeostasis.

• Korean Journal of Weed Science
• /
• v.32 no.2
• /
• pp.98-106
• /
• 2012

This research has been carried out to find out the highest effect on insecticidal, fungicidal and herbicidal activities in leaves, stem and tuber extracts of yacon (Smallanthus sonchifolius) and extraction methods such as water, boiling water and methanol. Characteristics of potential herbicidal components among extraction methods were investigated by solvent fractions such as hexane, chloroform, ethyl acetate, butanol, and water. Generally, methanol extract was the best on inhibition of germination rate, plant height, and root length in cucumber and barley. On the other hand, the inhibition effect on growth in cucumber and barley was the best in tuber among plant parts of yacon. Inhibition of germination rate, plant height, and root length in cucumber and barley in solvent fractions was the best in water fraction, but there were no differences in other fractions. Digitaria sanguinalis L. and Solanum nigrum L. by 5 and 10% extractions of yacon tuber were controlled by more than 70~80% and 95~100%, respectively. However, there was no inhibition effect on foliar treatment in cucumber and barley as affected by 5 and 10% extractions of yacon tuber. Mortality of green peach aphid (Myzus persicae Sulzer) was 50% at 3 days after treatment of 5% extracts of yacon leaves. Mortality of brown plant hopper (Nilaparvata lugens Stal) was only 24% in 5% extracts of stems and leaves with midrib, but was 57% in 5% extracts of leaves without midrib. There was no fungicidal effect on anthracnose (Colletotrichum truncatum), wilt disease (Fusarium oxysporum), verticillium wilt (Verticillium dahliae), bacterial blight (Xanthomonus oryzae) in 5% extracts of yacon leaves.

• Toxicological Research
• /
• v.24 no.1
• /
• pp.87-91
• /
• 2008

The present study was conducted to monitor the level of triflumizole residues in fruits (apple and pear) and vegetable (cucumber) samples in order to assess risk posed by the presence of such residues to the consumer. Triflumizole was applied at a recommended dose rate to apple and pear pulps and to a cucumber sample. The samples were collected at harvesting time following several treatments (three and/or four treatments). Triflumizole was extracted with methanol and re-extracted into dichloromethane. The presence of triflumizole was determined by HPLC with UV detection at 238 nm following the cleanup of the extract by open preparative chromatographic column with Florisil. The versatility of this method was evidenced by its excellent linearity (> 0.999) in the concentration range between 0.2 and 4.0 mg/kg. The mean recoveries evaluated from the untreated samples spiked at two different fortification levels. 0.1 and 0.4 mg/kg, and ranged from 87.5${\pm}$0.0 to 93.3${\pm}$2.6 for the tested fruits and vegetable, respectively, and the repeatability (as relative standard deviation) from three repetitive determinations of recoveries were no larger than 6%. The calculated limit of detection was 0.02 mg/kg and the minimum detectable level of 4 ng for triflumizole was easily detected. When triflumizole was sprayed onto the apple trees three times at 50-40-30 and 40-30-21 days prior to harvesting and four times onto the pear trees at 40-30-21-14 days prior to harvesting, the mean residual amounts of 0.05 and 0.06 mg/kg for apples and pears, respectively, were not detected in all of the treatments. When the cucumber sample was fumigated four times at 7, 5, 3 and 1 day prior to harvesting, the mean residual amount was not detectable. Triflumizole can be used safely when sprayed (wettable powder, 30% active ingredient) and fumigated (10%) 4 times at 14 and 1 day prior to harvesting to protect the fruits and vegetable, respectively.

• Research in Plant Disease
• /
• v.27 no.2
• /
• pp.61-65
• /
• 2021

Root-knot disease caused by Meloidogyne incognita is major soil pathogen and cause severe economic damages to vegetable crops. In this study, we selected rhizobacteria for biocontrol of the root-knot nematode, M. incognita, and identified; performed bioassay of the bacterial extracts in cucumber seedlings. The crude extracts of strains CT16 and JC05 out of 180 strains inhibited egg hatching and increased juvenile mortality in vitro assay; based on 16S rRNA sequences analysis, the two strains were identified as Bacillus sp. CT16, and Neobacillus sp. JC05. After extracting the bacterial supernatants by using various organic solvents, n-butanol and n-hexane extracts of strain CT16 and n-butanol extract of strain JC05 showed inhibitory activity of egg hatching depending on concentrations. Subsequently, n-butanol extracts of two strains significantly suppressed formation of egg masses in cucumber seedling. Therefore, these results indicated that strains CT16 and JC05 could be used as potential biocontrol agents against M. incognita.