• Korean Journal of Plant Resources
• /
• v.24 no.6
• /
• pp.719-723
• /
• 2011

Antimicrobial activities of methanol, ethanol, water, and $CH_2Cl_2$ extracts from Fritillaria unibracteata Hsiao et K.C. Hsia and F. ussuriensis Maxim. were investigated by disk-agar diffusion method. The result showed comparatively strong antimicrobial activity against several microorganisms. The extracts from F. unibracteata and F. ussuriensis dosedependently increased the activity. However, water and $CH_2Cl_2$ extracts showed no antimicrobial activity against 7 microorganisms. Especially, against the most sensitive microorganism Staphylococcus epidermidis, methanol extracts at highest concentration of 20 mg/mL exhibited the largest clear zone on plate by 6-12 mm and ethanol extracts on plate by 6-10 mm.

• Korean Journal of Food Science and Technology
• /
• v.45 no.3
• /
• pp.370-375
• /
• 2013

Propolis is a resinous mixture found in the tree buds, sap flows, and other botanical sources, which is used by honey bees in the construction of their hives. Antimicrobial effects of propolis were evaluated against Streptococcus mutans KCTC 3065, S. sobrinus KCTC 3308, S. sobrinus KCTC 5134, and Porphyromonas gingivalis KCTC 5352 by an agar diffusion assay. Sensitivity of these microorganisms to propolis was evaluated in broth containing different concentrations of propolis at $37^{\circ}C$, followed by observation using transmission electron microscopy (TEM). Propolis inhibited all oral microorganisms tested at the minimum inhibitory concentration (MIC) of $0.14mg/{\mu}L$ in the agar diffusion assay. Treatment with 0.06 and $0.22mg/{\mu}L$ of propolis had a bactericidal effect in a concentration- and treatment time-dependent manner against the tested microorganisms. TEM of propolis-treated S. mutans KCTC 3065 and P. gingivalis KCTC 5352 revealed structural damage of the cell membrane. The activity of propolis was affected by heat and pH treatment. The results indicate that propolis shows antibacterial activity against oral microorganisms and that it has potential for future applications in the food industry.

• Food Science and Biotechnology
• /
• v.18 no.2
• /
• pp.506-512
• /
• 2009

The antimicrobial activity of water and ethanol extracts from 30 species of algae was measured using the agar diffusion method and minimum inhibitory concentration (MIC) test. In agar diffusion method, the 95% ethanol extracts from 12 of the algae showed growth inhibition against the tested microorganisms. In particular, Ishige okamurai, Ecklonia stolonifera, Sargassum siliquastrum, Sargassum thunbergii, Colpomenia bullosa, and Ecklonia cava had strong antibacterial activities against Gram-positive bacteria at 4 mg/mL. In the results of the MIC test, S. siliquastrum showed the most antimicrobial activity, where its MIC values ranged from 0.005 to 0.0075% against Listeria monocytogenes, Clostridium perfringens, and Basillus subtilis. In the thermal stability test, for the ethanol extracts of I. okamurai, E. cava, S. siliquastrum, S. thunbergii, and C. bullosa, the extracts proved to maintain high antimicrobial activities when they were treated at $121^{\circ}C$ for 15 min. In the pH stability test, the antimicrobial activity of the S. siliquastrum ethanol extract was stable from pH 2 to 10, whereas the activity of the other species ethanol extracts were weakened under pH 10 against several microbes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.7
• /
• pp.1026-1034
• /
• 2016

To develop a natural antimicrobial agent, we investigated the antimicrobial activities of 13 species of edible herbal plant extracts against major Gram-positive foodborne bacteria. Among the 13 screened edible herbal plants, Caesalpinia sappan L. showed the highest antimicrobial activity. In the paper disc agar diffusion assay, Caesalpinia sappan L. extracts had strong antibacterial activities against most Gram-positive bacteria but did not have antibacterial activities against most Gram-negative bacteria. Minimum inhibitory concentrations of the ethanol extract were 0.06 mg/mL against Clostridium difficile and Listeria monocytogenes and 0.03 mg/mL against Staphylococcus aureus. Their inhibitory activities were not reduced by heat treatment or pH adjustment against C. difficile, L. monocytogenes, and S. aureus. Antimicrobial activities were higher in ethanol extract than in distilled water extract. These results support the potential use of Caesalpinia sappan L. ethanol extract as an antimicrobial agent or functional food components against Gram-positive bacteria.

• The Korean Journal of Food And Nutrition
• /
• v.23 no.2
• /
• pp.154-161
• /
• 2010

The aim of this study was to investigate antibacterial activities of essential oil from C. morifolium against four Grampositive bacteria and six Gram-negative bacteria. The antibacterial activity of the oils was determined by agar-well diffusion assay, minimum inhibitory concentration(MIC), and minimum bactericidal concentration(MBC). Essential oil of C. morifolium had a large inhibition zones especially against Salmonella enterica(21 mm) and Bacillus cereus(19 mm). Essential oil of C. morifolium generally showed higher antibacterial activity against Gram-positive bacteria than Gram-negative bacteria. MIC of essential oil from C. morifolium was 5 ${\mu}g/m{\ell}$ against ten food-borne pathogens. MBC values were determined to be from 5 to 20 ${\mu}g/m{\ell}$ against eight bacteria except Salmonella choleraesuis and Listeria monocytogenes. Therefore, the essential oil of C. morifolium and its components have a potent antibacterial activity against food-borne pathogens, and is expected to be used as a novel food preservative.

• Korean Journal of Microbiology
• /
• v.30 no.1
• /
• pp.65-69
• /
• 1992

It is proposed the polyacrylamide gel, instead of agar, could be used for the solid cultures of microorganisms including Streptomyces strains. Polymerization and gellation of 5% acrylamide solution were done by autoclaving for 5 min at 121.deg.C and no hindered by the addition of nutrient-rich media. In particular, pH buffer solution suitable for corresponding microorganisms must be used in the preparation of culture media. Comparing with agar, it was discussed that polycrylamide gel had many advantages such as gellation within the wide range of strong acid Carbon and Nitrogen sources, requirement tests of growth factors and minerals, sterization at high temperature, diffusion assays of products depending on the pore size of gel, and stability and standarization of microbial cultures.

• Proceedings of the Korean Society of Life Science Conference
• /
• 2008.10a
• /
• pp.43.2-43.2
• /
• 2008

• Advances in environmental research
• /
• v.9 no.3
• /
• pp.215-232
• /
• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• Korean journal of applied entomology
• /
• v.18 no.1 s.38
• /
• pp.11-14
• /
• 1979

Spinaches showing dark green mosaic symptoms were used for identification of broad bean wilt virus. In host reaction test, that virus caused local lesions on the inoculated leaves and mosaic symptoms on upper leaves of Chenopodium amaranticolor, Chenopodium quinoa and Vicia faba, and developed mosaic symptoms on Physalis floridana, Spinacia oleracea, Nicotiana tabacum, (White burley, Bright yellow) Nicotiana glutinusa. In agar gel-diffusion test, the virus showed positive reaction with broad bean wilt virus antiserum. Spherical virus particles with size of 25nm in diameter were observed in electron microscope.

• Korean journal of food and cookery science
• /
• v.26 no.2
• /
• pp.206-213
• /
• 2010

In this study, the antibacterial activities of essential oil from Zanthoxylum schinifolium against four Gram-positive bacteria and six Gram-negative bacteria were investigated. The antibacterial activity of the oils was determined using the agar-well diffusion assay, MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration). In particular, essential oil from Z. schinifolium showed higher antibacterial activity against Gram-positive bacteria than against Gram-negative bacteria. Essential oil from Z. schinifolium displayed large inhibition zones especially against Bacillus cereus (31 mm). At concentrations between 0 and $20\;{\mu}g/mL$ the oils showed an antibacterial effect against both Gram-negative and Gram-positive bacteria. The minimum inhibitory concentration (MIC) values against nine bacteria ranged from 1.25 to $5\;{\mu}g/mL$. The minimum bactericidal concentration (MBC) values against eight bacterial ranged from 2.5 to $20\;{\mu}g/mL$, except Shigella sonnei. Furthermore, our finding on the antibacterial activities of essential oils from Zanthoxylum schinifolium validated the use of this plant for medical purposes.