• Plant Disease and Agriculture
• /
• v.5 no.1
• /
• pp.1-7
• /
• 1999

The grain rot of caused by Bukholderia glumae was fist reported in japan in 1955 and then reported in other countries as well as in Korea in 1986. The pathogen causes both seedling and grain rot of rice but it cannot attack any other parts of adult rice plant. Bacterial colonies grow slowly, and are circular and greyish white. The causal bacterium is Gram-negative and rod shape with 1-3 polar flagella, and produce a diffusible yellow-greenish nonfluorescent pigment on King's medium B. Biochemical characteristics such as negative in arginine dehydrolase, oxidase reaction and nitrate reduction and positive in lecithinase, and the utilization of L-arginine and inositol are useful in differentiation of this from other nonfluorescent bacteria pathogenic to rice. This pathogenic bacterium had belonged to the genus of Pseudomonas but recently was transferred to the new genus Burkholderia on the basis of physiological characteristics and DNA-DNA hybridization data. However, other characteristics such as colony heterogenicity or colonial variation after subcultures, phytotoxin, secreting antibiotics, and relationship between yellow greenish pigment production and pathogenicity need to be clarified more. To develop an effective control strategy for this disease, understanding of detailed life cycle of the disease and critical environmental factors affecting disease development is prerequisite. Although 5,435 ha of rice paddy in Korea was infested during 1998, there is no exact estimation of yield losses and distribution of the pathogen. The review will focus on recent progress on the understanding of the bacteriological and ecological characteristics of the causal bacterium and control means of the disease.

• Microbiology and Biotechnology Letters
• /
• v.41 no.3
• /
• pp.278-283
• /
• 2013

A gram-positive, rod-shaped, spore-forming, motile thermophilic bacterium was isolated from a sterilization oven. The microorganism GWE1, formally named Geobacillus wiegelii identified as a member of the genus Geobacillus. GWE1 grew under aerobic conditions of between $60-80^{\circ}C$ (optimum $670^{\circ}C$), in a pH range of 3.0-8.0 (optimum $pH^{70^{\circ}C}$ 5.8), and between 0 and 2 M NaCl (optimum 0.3 M). The membrane polar lipids were dominated by branched saturated fatty acids, which included as the major constituents; iso-15:0 (13.3%), 16:1(${\omega}7$) (12.8%), 16:0 (28.5%), iso-17:0 (13.5%) and anteiso-17:0 (12.3%). The DNA G+C content was 47.2 mol% (determined by HPLC). The 16S rRNA gene sequence of GWE1 showed a high similarity with Geobacillus caldoxylosilyticus (97%). However, the level of DNA-DNA relatedness was only 58%. These data suggest that GWE1 is probably a novel specie of the genus Geobacillus.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.6
• /
• pp.553-556
• /
• 2006

A cis-1,2-dichloroethylene (cis-DCE)-degrading anaerobic bacterium, Clostridium sp. strain KYT-1, was isolated from a sediment sample collected from a landfill site in Nanji-do, Seoul, Korea. The KYT-1 strain is a gram-positive, endospore-forming, motile, rod-shaped anaerobic bacterium, of approximately $2.5{\sim}3.0\;{\mu}m$ in length. The degradation of cis-DCE is closely related with the growth of the KYT-1 strain, and it was stopped when the growth of the KYT-1 strain became constant. Although the pathway of cis-DCE degradation by strain KYT-1 remains to be further elucidated, no accumulation of the harmful intermediate, vinyl chloride (VC), was observed during anaerobic cis-DCE degradation. Strain KYT-1 proved able to degrade a variety of volatile organic compounds, including VC, isomers of DCE (1,1-dichloroethylene, trans-1,2-dichloroethylene, and cis-DCE), trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane. Strain KYT-1 degraded cis-DCE at a range of temperatures from $15\;to\;37^{\circ}C$, with an optimum at $30^{\circ}C$, and at a pH range of 5.5 to 8.5, with an optimum at 7.0.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.474-477
• /
• 2000

An organic solvent-tolerant Pseudomonas savastanoi strain BCNU 106 was isolated.. This bacterium was gram negative rod, and showed oxidase positive, catalase positive, and decaboxylase positive reactions. The Pseudomonas strain oxidized cholesterol on the medium supplemented with an organic solvent. The strain BCNU 106 is able to grow in presence of organic solvents of which log $P_{ow}$ is between 1.5 to 7.0. The strain was well grown in a medium supplemented with a 10% volume of a organic solvent (toluene, p-xylene, cyclohexane, mesitlylene) containing $cholesterol(20mg/m{\ell)$. Major conversion compound were 7-dehydrocholesteryl dimethylphosphate, cholesta-4,7-dien-3-one, and cholesta-3,5-dieone.

• Advances in Traditional Medicine
• /
• v.8 no.4
• /
• pp.339-348
• /
• 2008

Butea frondosa has been used traditionally as a topical formulation in the treatment of many diseases and disorders. Two compounds [BF-1 (crystalline flavonol quercetin) and BF-2 (tannin) from ethyl acetate fraction of ethanolic extract] were isolated from the bark of Butea frondosa. The stereostructures of the compounds were determined on the basis of chemical and physicochemical evidence. BF-1 and BF-2 were screened in vitro for possible antibacterial property against 112 bacteria comprising 3 genera of Gram-positive and 12 genera of Gram-negative types. It was found that both BF-1 and BF-2 exhibited inhibitory activity against several bacteria. Most of these strains were inhibited by BF-1 at $50-200\;{\mu}g/ml$, while BF-2 ($MIC_{50}$ $400\;{\mu}g/ml$) was much less active. The bacteria could be arranged in the decreasing order of sensitivity towards BF-1 in the following manner: S. aureus, Bacillus spp., Salmonella spp., Vibrio spp., Shigella spp., E. coli and Pseudomonas spp. The $MIC_{50}$ of the compound was $50\;{\mu}g/ml$ while the $MIC_{90}$ was $100\;{\mu}g/ml$. The decreasing order of sensitivity towards BF-2 was V. cholerae, Bacillus spp., S. aureus, V. parahaemolyticus, Salmonella spp. and Proteus spp. BF-1 was bactericidal in action. In vivo studies with this extract showed that it could offer statistically significant protection (p < 0.01) to mice challenged with a virulent bacterium. The inhibitory activity of Butea frondosa against Gram-positive and Gram-negative bacteria indicates its usefulness in the treatment of common bacterial infections. The potentiality of BF-1 as an antibacterial agent may be confirmed further by pharmacological studies.

• Mycobiology
• /
• v.35 no.4
• /
• pp.210-214
• /
• 2007

Antibacterial and antifungal activities of liquid culture filtrate, water and ethanol extract (solid culture) of Stereum ostrea were evaluated against 5 bacteria and 3 plant pathogenic fungi. To determine the minimal inhibitory concentration (MIC), we studied $5{\sim}300\;mg/ml$ concentrations against bacteria and fungi separately. The MIC was 10 mg/ml for Bacillus subtilis and 40 mg/ml for Colletotrichum gloeosporioides and Colletotrichum miyabeanus. Liquid culture filtrate was more effective against Gram positive than Gram negative bacteria, and Staphylococcus aureus was the most inhibited (20.3 mm) bacterium. Water and ethanol extracts were effective against both Gram positive and Gram negative bacteria, and water extract was better than ethanol extract. In water and ethanol extract, inhibition zones were 23.6 and 21.0 mm (S. aureus) and 26.3 and 22.3 mm (Pseudomonas aeruginosa), respectively. For plant pathogenic fungi, the highest and lowest percent inhibition of mycelial growth (PIMG) was found 82.8 and 14.4 against C. miyabeanus and Botrytis cinerea in liquid culture filtrate, respectively. In water extract, the PIMG was found to be the highest 85.2 and lowest 41.7 for C. miyabeanus and C. gloeosporioides, respectively. The inhibitory effect of ethanol extract was better against C. miyabeanus than C. gloeosporioides and B. cinerea. Among 3 samples, water extract was the best against tested pathogenic fungi. This study offers that the extracts isolated from S. ostrea contain potential compounds which inhibit the growth of both bacteria and fungi.

• Korean journal of food and cookery science
• /
• v.13 no.3
• /
• pp.330-337
• /
• 1997

The sensitivity of various pathogenic bacteria (Aeromonas hydrophila, Estherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus 196E, Salmonella typhimurium and Vibrio parahaemolyticus) to the spices, allspice, clove, oregano, and thyme, was tested. Tryptic soy broth (TSB) containing 0∼2% (w/v) of spices was inoculated with 10sup 5/∼10$\^$6/ cells/$m\ell$ of each bacterium and incubated at 35$^{\circ}C$ for 24 hr. The growth of pathogenic bacteria was inhibited with increasing concentrations of spices in the culture broth. At 2％ spice concentration, Gram positive bacteria were more sensitive than Gram negative bacteria with the exception of V. parahaemolyticus. Clove had the highest antibacterial activity, followed by allspice and oregano. At the concentration of 0.3%, clove inhibited the growth of all strains tested. Kanagawa-positive strain of V. parahaemolyticus displayed the highest sensitivity to clove and allspice. Thyme was the least effective for growth inhibition, while 1％ clove killed all pathogens tested.

• Journal of Korean Society of Water and Wastewater
• /
• v.33 no.3
• /
• pp.191-204
• /
• 2019

The 20-kHz ultrasonic irradiation was applied to investigate bacterial inactivation and antibiotic susceptibility changes over time. Applied intensities of ultrasound power were varied at 27.7 W and 39.1 W by changing the amplitude 20 to 40 to three bacteria species (Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus). By 15-min irradiation, E. coli, a gram-negative bacterium, showed 1.2- to 1.6-log removals, while the gram-positive bacteria, Enterococcus faecalis and Staphylococcus aureus, showed below 0.5-log removal efficiencies. Antibiotic susceptibility of penicillin-family showed a dramatic increase at E. coli, but for other antibiotic families showed no significant changes in susceptibility. Gram-positive bacteria showed no significant differences in their antibiotic susceptibilities after ultrasound irradiation. Bacterial re-survival and antibiotic susceptibility changes were measured by incubating the ultrasound-irradiated samples. After 24-hour incubation, it was found that all of three bacteria were repropagated to the 2- to 3-log greater than the initial points, and antibiotic inhibition zones were reduced compared to ones of the initial points, meaning that antibiotic resistances were also recovered. Pearson correlations between bacterial inactivation and antibiotic susceptibility showed negative relation for gram-negative bacteria, E. coli., and no significant relations between bacterial re-survival and its inhibition zone. As a preliminary study, further researches are necessary to find practical and effective conditions to achieve bacteria inactivation.

• KSBB Journal
• /
• v.26 no.6
• /
• pp.543-551
• /
• 2011

Bacterial antibiotic resistance is a real and growing problem for both Gram positive and Gram negative bacterial pathogens in the hospital setting. Among Gram negative bacteria, the ubiquitous bacterium Pseudomonas aeruginosa is a particular concern in immunocompromised and burn patients. The present study evaluated antibacterial activity and efficacy of a Korean herbal medicine against eight multi-drug resistant clinical isolates of P. aeruginosa (0225, 0254, 0347, 0826, 1113, 1378, 1731, and 2492) isolated at Daegu Catholic University Hospital. Methanol extracts of Galla rhois (5 and 10 mg/mL) displayed inhibition diameters for isolate 2492 of 10 and 12 mm, respectively, in a conventional disc diffusion assay. In seven kinds of Korean herbal medicines, increased inhibitory power of Lonicera japonica, Gardenia jasminoides, Galla rhois, and Scultellaria baicalensis was evident with the fermentation of six kinds of lactic acid bacteria. Three lactic acid bacteria (Lactobacillus plantarum subsp. plantarum KCTC 3108, L. casei KCTC 3109, and L. fermentum KCTC 3112) were identified as excellent strains for the production of antibacterial materials. In the six Korean herbal medicine extracts, strong inhibitory activity of fermented Forsythia suspensa, Glycyrrhizae radix, Lycium chinense, Platycodon grum, and Schizandra chinensis with five kinds of lactic acid bacteria was evident for seven multi-drug resistant P. aeruginosa isolates.

• Journal of fish pathology
• /
• v.20 no.3
• /
• pp.221-227
• /
• 2007

In this study, one hundred strains of bacterial flora were isolated from the intestine of cultured and wild black rockfish Sebastes inermis collected in Yeosu and examined for drug resistance to 9 antibiotics. From cultrued fish, the isolated bacteria were Photobacterium group (26 strains) and Acinetobacter group (18 strains) of Gram-negative, and unidentified marine sediment bacterium (6 strains) of Gram-positive. From wild fish, Photobacterium group (18 strains), Acinetobacter group (12 strains) and Shewanella group (5 strains) of Gram-negative and Bacillus group (8 strains), Staphylococcus group (4 strains), and unidentified marine sediment bacterium (3 strains) of Gram-positive. Intestine flora of wild black rockfish was more diverse than that of one cultured. The drugs tested were tetracyclines (oxytetracycline), aminoglycosides (gentamicin), macrorides (erythromycin) and quinolones (flumequine, oxolinic acid, norfloxacin, ofloxacin, enrofloxacin and ciprofloxacin). Sensitivity to all seven antibiotics except oxytetracycline and oxolinic acid was higher in bacteria from wild fish than from cultured ones, although wild isolates were more resistant than control strain Escherichia coli ATCC9637. This suggests that use of antibiotics in the fish farm might have some resistance in intestinal flora of wild fish.