• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.60-66
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• 1996

Bradyrhizobium japonicum with different colony morphology populated in five Yeongnam soils of Korea was examined for intrinsic antibiotic resistance to eight antibiotics, serological property by immunoblot and immunodiffusion, and protein profile differentiation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Colony morphological distribution of one hundred and twenty B. japonicum isolates was 47% for "dry". 41% for "wet", and 12% for "dry/wet" type. The total isolates showed such a strong correlation between the morphology and antibiotic resistance. Colony morphology, which though was dominantly consisted of the same type within a serogroup, wasn't absolutely linked to serological property of B. japonicum. Based on these data, colony morphology was too simple to identify variations with B. japonicum isolates : antibiotic resistance such complicated compared with serological analyses.

• Journal of fish pathology
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• v.7 no.1
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• pp.37-46
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• 1994

A total 103 strains of Edwardsiella tarda was isolated from eel culture-ponds and examined for drug resistance, distribution and transferabilities of R plasmids. The drugs used were lincomycin(LM), penicillin(PM), sulfamethazine(SF), sulfadimethoxine(SD), cephalosprin(CP), chloramphenicol(CH), streptomycin(SM), oxytetracycline(OT), ampicillin(AP), oxolinic acid(OA), kanamycin(KM), amikacin(AK), gentamicin(GM) and enrofloxacin(EF). Two strains were resistant to the all drugs used, and all isolates were multiply resistant to drugs(at least 8 among 14 drugs), mostly restricted to LM(103 strains), PM(103 strains), SD(103 strains), SF(103 strains), CP(102 strains), CM(101 strains), SM(100 strains), OT(94 strains), AM(92 strains), OA(80 strains), KM(60 strains), AK(30 strains), GM(19 strains) and EF(14 strains), in combination at high degree showing 34 different drug resistant patterns. The most frequently encountered patterns were LM PM SD SF CP CH SM OT AP OA KM(22 strains, 22.4%) followed by LM PM SD SF CP CH SM OT AP OT(12 strains, 11.7%). LM PM SD SF CP CH SM OT AP(7 strains, 6.8%), LM PM SD SF CP CH SM OT AP OA KM AK GM(6 strains, 5.8%) and LM PM SD SF CP CH SM OT AM OX KM AK GM(6 strains, 5.8%). Transfer experiment of drug resistance showed that of 103 resistant strains, 100 strains(97%) transferred part or all resistance to all drugs, indicating that most isolates carried conjugally transferrable R plasmids determining multiple drugs. The most frequently observed transferarble R plasmids were LM PM SD SF CP CH SM OT AP OA(10 strains), LM PM SD SF CP CH SM OT AP OX KM(7 strains) and LM PM SD SF CP CH AP OA(7 strains). These results sugested that eel culture-ponds were highly contaminated with different strains of Edwardsiella tarda, and that contaminated bacteria might be highly multiple resistant strains to drugs, carring transferable R plasmids.

• Tuberculosis and Respiratory Diseases
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• v.63 no.2
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• pp.128-138
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• 2007

Backgrounds: Mutations of katG and inhA (ORF and promoter) are known to be related to isoniazid (INH) resistance of Mycobacterium tuberculosis. Because reports on these mutations in Korean isolates are limited (i.e. only the frequency of katG codon 463 was evaluated.), we tried to know the kinds of mutations of two genes and their frequencies in INH resistant Korean M. tuberculosis strains. Methods: PCR was performed to amplify katG (2,223 bp), inhA ORF (-77~897, 975 bp), and inhA promoter (-168~80, 248 bp) from 29 multidrug resistant M. tuberculosis (MDR-TB) DNAs prepared by bead beater-phenol method. Their sequences were determined and analyzed by ABI PRISM 3730 XL Analyzer and MegAlign package program, respectively. Results: All of the isolates had more than one mutation in katG or inhA gene. Twenty seven (93%) of 29 tested strains had katG mutations, which suggests that katG is a critical gene determining INH resistance of M. tuberculosis. Amino acid substitutions, such as Arg463Leu and Ser315Thr, due to point mutations of the katG were the most frequent (62.1% and 55.2%) mutations. In addition, deletion of the katG gene was frequently observed (17.2%). Analyzed Korean MDR-TB isolates also had variable inhA mutations. Point mutation of inhA promoter region, such as -15 ($C{\rightarrow}T$) was frequently found. Substitution of amino acid (Lsy8Asn) due to point mutation ($AAA{\rightarrow}AAC$) of inhA ORF was found in 1 isolate. Interestingly, 14 point mutated types that were not previously reported were newly found. While four types resulted in amino acid change, the others were silent mutations. Conclusions: Although it is not clear that the relationship of these newly found mutations with INH resistance, they show marked diversity in Korean MDR-TB strains. It also suggests their feasibility as a molecular target to supplement determining the INH resistance of clinical isolates because of the possible existence of low-level INH resistant strains.

• Journal of Korean Society of Forest Science
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• v.88 no.1
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• pp.31-37
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• 1999

The frequency of gall formation by pine needle gall midges ranged from 35% to 40% in both P. densiflora and P. thunbergii species. However, there was no indication of gall development from larva on both P. virgiana and P. rigida species suggesting that some specific compounds might play role in preventing gall formation of larva. The susceptible species to pine needle gall midges including P. densiflora and P. thunbergii contained a little salicylic acid under the free phenolic compound conditions while the resistant species against such insects including P. virginiana and P. rigida species contained about 37ppm to 50ppm of salicylic acid. Thus, this compound might have important roles in insect resistance. The contents of internal salicylic acid in the needles of susceptible pines increased from 9.5ppm to 20.6ppm after direct external irrigation of salicylic acid solution and flour treatment on roots. As a result, the frequency of gall formation decreased dramatically 17~19 times lower when compared with that of control. According to our results, the application of salicylic acid for effective prevention against insect damages should be performed before hatching eggs. The frequency of gall formation in the hybrid pines of P. thunbergii(susceptible) and P. virginiana(resistant) showed approximately 24% as average value of those in both species. In the case of specific individuals, it ranged from 2.8% to 11.5% in hybrids of both species. Therefore, effective production of insect resistant pines can be obtained through hybrids by crossing between susceptible and resistant species including P. thunbergii and P. virginiana by increasing internal salicylic acid contents of the needles.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.44-50
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• 2015

The purpose of this study was to characterize the lactic acid bacteria found in makgeolli in terms of bacterial identity and gastric compatibility. Lactic acid bacteria were isolated from commercial raw makgeolli and separated into six strains that are resistant to gastric acidity and bile acid. These strains were identified by analysis of their 16S rDNA, as Lactobacillus plantarum BSM-2 and EHJ-1, Lactobacillus casei GSM-3 and EHJ-2, Lactobacillus brevis BSM-3 and Pediococcus pentosaceus TJH-1. All strains exhibited adhesion to intestines, showing that they were probiotic. We also found that L. plantarum BSM-2 had excellent resistance to bile acid as well as antioxidant activity. Taken together with its antibacterial properties and ability to lower cholesterol, our data suggest that L. plantarum BSM-2 was the most beneficial probiotic among the six strains.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.9-14
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• 2010

In this study, lactic acid bacteria with high angiotensin converting enzyme inhibitor activity were isolated from Korean fermented food, such as kimchi and salted seafood. The strain HLJ59, isolated from salted shrimp showed the highest angiotensin converting enzyme inhibitor activity in DeMan Rogosa Sharpe broth. Optimum growth temperature of Lactobacillus brevis HLJ59 was at $34^{\circ}C$. Acid treatment at pH 3.0 for 1.5 h decreased cell viability from $9.9{\times}10^8$ CFU/ml to $3.11{\times}10^4$ CFU/ml. The bile extract concentration of 0.3%, 0.5%, and 1.0% in MRS broth did not inhibit the growth of HLJ59. Isolated strain HLJ59 showed more sensibility to amikacin, gentamycin, neomycin, streptomycin, kanamycin, cefmetazole, cephalothin, ampicillin, ticarcillin, sulbactam+ampicillin, amoxicillin+clavulanic acid (AMC), tetracycline, and sulfamethoxazole+trime thoprim (SXT) as compare to other 7 different antibiotics. However, it showed more resistance to cefoxatin, ceftnaxone, penicillin, ciprofloxacin, nalidixic acid, lincomycin, and chloramphenicol.

• Food Science of Animal Resources
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• v.28 no.1
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• pp.82-90
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• 2008

Two strains of pure lactic acid bacteria capable of forming both acid and slime were isolated from the kefir made of goat milk. The isolated strains observed by morphological and physiological properties, and their 16S rDNA partial sequence were identified as Streptococcus salivarius subsp. thermophilus(LFG-1) and Lactococcus lactis subsp. lacits(LFG-2) with over 99% homology. The optimum temperature of Str. salivarius subs. thermophilus LFG-1 for growth was $40-45^{\circ}C$, and its generation time was 40.6 minutes. The final pH of cultured broth by Str. salivarius subsp. thermophilus LFG-1 and the commercial strain Str. thermophilus Body-1 for 24hr at $37^{\circ}C$ were 4.30 and 4.55, respectively. The coagulative activity of Str. salivarius subsp. thermophilus LFG-1 was almost as strong as that of commercial strain Str. thermophilus Body-1. However, the LFG-2 strain showed lower coagulative activity than Str. thermophilus Body-1. The survival rate of lactic acid bacteria were between 22-29% in 0.3% bile extract. At pH 1.0 all of the bacteria were killed, and most of lactic acid bacteria died against pH 3.0. However, all lactic acid bacteria survived well at pH 4.5.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.308-312
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• 2011

Plant lactic acid bacteria were isolated from plant-associated fermentative foods and crops, and their probiotic properties were investigated. Isolates K27 and O2 were isolated from Kimchi and onion, and identified as Lactobacillus plantarum on the basis of 16S rRNA gene analysis. The two strains were highly resistant to acid (an MRS broth at pH 2.5), where the survival rates of L. plantarum K27 and L. plantarum O2 were 90.2% and 97.3%, respectively. L. plantarum K27 and L. plantarum O2 also showed high bile resistance to 0.5% oxgall, with a more than 70% survival rate. They showed an inhibitory effect against pathogenic strains of Escherichia coli KCCM 40880 and Pseudomonas aeruginosa ATCC 10145. The antibacterial effect of the two strains was probably due to the presence of lactic acid. ACE inhibitory activities of the two strains ranged from 72.8% to 80.6% in MRS broth. Notably, the two strains showed high ACE inhibitory activity (89.2~98.2%) in MRS broth containing 10% skim milk. Antioxidant activity was tested by DPPH radical scavenging activity, with antioxidant activities of the strains being in the range of 56.8~61.5%. The results obtained in this study suggest that L. plantarum K27 and L. plantarum O2 may be potential probiotic starter cultures with applications with fermentative products.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.244-250
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• 1996

The objectives of this paper were to study the existence of resistant substance to pine gall midge from needles of Pinus densiflora, P. thunbergii, P. virginiana, and P. thunbergii${\times}$P. virginiana, and also to investigat whether terpenoids, fragrant substance contained in those species seduce or evade imago of pine gall midge to oviposit. Also, terpenoids and phenolic compounds were bioassayed on larva. The results are follows. Adults of pine gall midge oviposited indiscriminately all investigated pine species, while gall formation rate by pine gall midge showed 0% in Pinus virginiana, 9% in P. thunbergii${\times}$P. virginiana, 22% in P. thunbergii. It is suggested that young larvae is necrotized by resistant substance in the needles of P. virginiana. This results might mean that fragrant substance, terpenoids, extracted from pine species is not seducible or evadable substance. Larvae of pine gall midge placed on terpenoid and resin were not necrotized. The necrosis rate of larvae of pine gall midge cultivated in the solution of phenolic compounds extracted from needles of P. virginiana, salicylic acid and chitinase showed 89, 92, and 86% respectively. And necrosis rate was 56 and 59% in phenolic compounds extracted from P. densiflora and gallic acid respectively. So, it is postulated that phenolic compounds contained in needles of P. virginiana, salicylic acid and chitinase are resistant substance to pine gall midge.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.129-133
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• 2012

To exploit plant growth promoting bacteria in the roots of Miscanthus sacchariflorus, a biomass energy crop, total 64 bacteria were isolated. For the investigation of plant growth promoting effects from the isolated bacteria, production of indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activities were tested and other cultural conditions were examined. As results, 8 isolates showed plant growth promoting effects on the M. sacchariflorus and an isolate designated Agrobacterium sp. BE516 has the highest activity by enhancing the shoot elongation over 2-fold than the control. Agrobacterium sp. BE516 produced 64 ${\mu}g$ IAA per mL and showed ACC deaminase activity which is involved in the resistance to environmental stress such as high salt and drought. It could grow at low temperature in the range from 4 to $15^{\circ}C$, at pH 4.0 and at 4% NaCl. These results indicate that the Agrobacterium sp. BE516 can be useful as a bio-fertilizer for M. sacchariflorus under the stressed conditions.