• Journal of fish pathology
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• v.22 no.3
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• pp.317-326
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• 2009

This study has shown the screening of anti-bacterial activity of three Indian medicinal plant choloroform : methanol (50:50) solvent leaf extracts (i.e. Azadirachta indica, Ocimum sanctum, and Curcuma longa) with different concentrations (10, 5, 2.5, 1.25, 0.625, 0.312, and 0.156 mg/ml) under in vitro conditions against fish pathogenic bacteria, Aeromonas hydrophila, Streptococcus iniae, Vibrio harveyi, V. anguillarum, and Edwardsiella tarda isolated from olive flounder farms, Jeju Island, South Korea. The anti-microbial activity of the A. indica and O. sanctum extracts yielded the zones of growth inhibition (ZI) was 3 and 1mm against A. hydrophila at concentration of 0.156 mg/ml when compared to that of tetracycline standard (3 mm). At highest concentration (10 mg/ml) of A. indica, O. sanctum, and C. longa, high inhibition was 9, 7, and 6 mm when compared to that of tetracycline (11 mm) against A. hydrophila. The minimum inhibitory concentration (MIC) of A. indica, O. sanctum, and C. longa at 0.156 mg/ml that yield 9, 10, and 13 CFU/ml for A. hydrophila, 16, 22, and 25 CFU/ml for S. iniae and 18, 22, and 23 CFU/ml for E. tarda compared to the tetracycline. At highest concentration (10 mg/ml) of the three extracts was better inhibiting the growth of A. hydrophila, S. iniae and E. tarda. A. indica, O. sanctum, and C. longa were determined to the potential antioxidant activityon the basis of their scavenging activity of the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. A. indica extract was 0.625 mg/ml which indicated that the strong anti-oxidant activity. However, O. sanctum and C. longa extracts showed weak anti-oxidant activity at this concentration. Hence, in vitro assay among the pathogens, A. hydropila is better inhibitory activity of the extracts. It is evident that the Indian medicinal plants extracts were subjected to its effectiveness against A. hydrophila, S. iniae, and E.tarda at low concentrations. The obtained results in the present study suggested that the Indian plant extracts is a prevention tools for Korean olive flounder aquaculture pathogens and its need further advance investigation.

• Mycobiology
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• v.36 no.2
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• pp.121-133
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• 2008

Aspergillus niger isolated from Allium sativum was used at large scale fermentation (150 mg flavone/200ml medium) to obtain suitable amounts of the products, efficient for identification. Then spectral analysis (UV, IR, $^1H$-NMR, $^{13}C$-NMR) and mass spectrometry were performed for the two products, which contributed to the identification process. The metabolite (1) was identified as 2'-hydroxydihydrochalcone, and the metabolite (2) was identified as 2'-hydroxyphenylmethylketone, which were more active than flavone itself. Antioxidant activities of the two isolated metabolites were tested compared with ascorbic acid. Antioxidant activity of metabolite (1) was recorded 64.58% which represented 79% of the antioxidant activity of ascorbic acid, and metabolite (2) was recorded 54.16% (67% of ascorbic acid activity). However, the antioxidant activity of flavone was recorded 37.50% which represented 46% of ascorbic acid activity. The transformed products of flavone have anti-microbial activity against Pseudomonas aeruginosa, Aspergillus flavus and Candida albicans, with MIC was recorded $250{\mu}g/ml$ for metabolite (2) against all three organism and 500, 300, and $300{\mu}g/ml$ for metabolite (1) against tested microorganisms (P. aeruginosa, Escherichia coli, Bacillus subtilis, and Klebsiella pneumonia, Fusarium moniliforme, A. flavus, Saccharomyces cerviceae, Kluveromyces lactis and C. albicans) at this order.

• KSBB Journal
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• v.13 no.5
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• pp.469-476
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• 1998

Among 31 water-born microbial strains isolated from various sites in Korea, strain DJ-4 was selected as a test organism for toxicity measurements in that its growth was completely inhibited by the presence of 668.4 mg/L of chloroform and 297.5 mg/L of toluene in the liquid LB medium whereas others did not. It was observed that lag periods and specific growth rates of DJ-4 batch vial cultures were prolonged and decreased, respectively, by phenol, benzene, toluene, ethylbenzene, p-xylene, perchloroethylene, trichloroethylene, and chloroform at the concentrations between 3.6 and 417.8 mg/L. There changes were found to be linear with respect to the concentrations of the toxic compounds. From the first-order regression equations, 50% effective concentrations (EC50${\mu}$ for concentrations of toxic compounds causing 50% decrease of specific growth rates and EC50lag for 50% increase of length of lag periods) were calculated for each compounds. By comparing DJ-4 EC50${\mu}$ values with Daphnia LC50's from a literature for benzene, ethylbenzene, toluene, and trichloroethlyene, it was concluded that microbial specific growth could be a new, fast, and reliable parameter for toxicity tests.

• Journal of Food Hygiene and Safety
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• v.9 no.4
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• pp.191-198
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• 1994

The major purpose of the present study is to syrvey vegetables, meats, seafoods, processed foods and imported foods for the presence of Listeria spp. and to prevent listeriosis caused by the contamination of Listeria monocytogenes. Listeria spp. was not found in vegetables and processed foods. The optimum growth condition of isolates indentified as Listeria monocytogenes was pH 7.0 and 37$^{\circ}C$. the antimicrobial effect of grapefruit seed extract(GFSE) was observed in the level of more than 100ppm by disk method. When 1ml(2.5$\times$106 CFU/ml) of Listeria monocytogenes was inoculated and incubated for 3 days at 3$0^{\circ}C$, the total cell number of the organism was 4.5$\times$109 in the control, 7.2$\times$103 in 100 $\mu\textrm{g}$/ml of GFSE medium, and 3.5 $\mu\textrm{g}$/ml of GFSE medium. Direct visualization of microbial cells by using both transmission electron microscope and scanning electron microscope showed microbial cell membrane the function of which was destroyed by treating with the dilute solutions of GFSE. It could be confirmed that GFSE completely inhibited the growth of the test strain of Listeria monocytogenes.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.95-99
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• 2000

The microbial contamination rate of contact lens cases in multi-purpose solution(MPS) care systems of 80 asymptomatic soft contact lens wearers was investigated. In caring for their lenses 72 patients (90%) used chemical disinfection(include MPS), six patients(7%) used hydrogen peroxide, and two patients(3%) used heat. Fifty-nine percent of patients used MPS in their care systems. Of 80 contact lens cases, contamination was found in 68%(54) of cases. There is a significant relationship between the ages of lens cases and contamination: older cases being more frequently contaminated. Of the contaminated 31 lens cases(57%) in MPS care systems, four contact lens cases(13%) were contaminated by single organism, 15 cases(48%) by two kinds of organisms, and 12 cases(39%) by more than three kinds of organisms. Of the organisms that were contaminated lens cases, Pseudomonas. Serratia, Bacillus, E. coli and Aspergillus were frequently isolated. When considering the high contamination rate of soft contact lens cases in MPS care systems more effective and hygienical lens care system is important, especially frequent and regular disposal of lens cases may prove to prevent the build-up of microbial colonisation in containers.

• Journal of Life Science
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• v.12 no.5
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• pp.610-621
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• 2002

Conserved genes are importantly used to understand the major function in survival and replication of living organism. This study was focused on identification of conserved genes in microbial species and measuring the degree of conservation. For this purpose, in silico analysis was performed to search conserved genes based on the conservation level within microbial species. The ortholog list of COGs (Clusters of Orthologous Groups of proteins) in NCBI was used and whole genomes of 43 microbial species were included in that list. The distance value, derived from CLUSTALW multiple alignment program, was used as a descriptor of the conservation level of orthologs. It was revealed that 43 microbial genomes hold 72 conserved orthologs in common. The majority(72.2%) of the conserved genes was related to "translation, ribosomal structure and biogenesis" functional category. A GTPase-translation elogation factor(COG0050) was the best conserved gene from the distance value analysis. The 72 conserved genes, found in this research, would be useful not only to study minimal function genes but also new drug target among pathogens and to make a model of the virtual cell.tual cell.

• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.1
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• pp.143-154
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• 2009

Single nucleotide polymorphisms (SNPs) are the most frequent form of variation in the genome of any organism. Owing to their greater abundance, they are considered useful for identifying cultivars, construction of higher density linkage maps, and detection of genes (QTLs) associated with complex agronomic traits and diseases. Although, SNPs have been used recently for constructing a high density genetic map in silkworm and a set of 118 SNPs have been identified in tasar silkworms, not much progress has been made in sericulture to utilize the vast potential of SNPs. Thus, this review mainly focuses on some of the important methods of SNP discovery, validation and genotyping. Emphasis has also been given to the possible uses of SNP genotyping in the improvement of silkworms and their host plants.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.807-822
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• 2016

Starting as a glutamate producer, Corynebacterium glutamicum has played a variety of roles in the industrial production of amino acids, one of the most important areas of white biotechnology. From shortly after its genome information became available, C. glutamicum has been applied in various production processes for value-added chemicals, fuels, and polymers, as a key organism in industrial biotechnology alongside the surprising progress in systems biology and metabolic engineering. In addition, recent studies have suggested another potential for C. glutamicum as a synthetic biology platform chassis that could move the new era of industrial microbial biotechnology beyond the classical field. Here, we review the recent progress and perspectives in relation to C. glutamicum, which demonstrate it as one of the most promising and valuable workhorses in the field of industrial biotechnology.

• Microbiology and Biotechnology Letters
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• v.25 no.5
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• pp.490-494
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• 1997

A variety of microbial strains isolated from soil were tested for their ability to produce D-tagatose from D-galactose. An organism that can convert D-galactose into D-tagatose was selected and was identified as Enterobacter agglomerans. The cells grown on the induction medium containing 20 g/l arabinose were found to the best conversion potential among different carbohydrates and the conversion yield was about 15% when 20 gll galactose was used. The isolated crystals were obtained from the culture broth after the purification process such as treatment of ion resins, crystallization, and drying. The recovery yield was 70% after the purification. The crystals were identified as D-tagatose by the infrared spectroscopy, HPLC, specific optical rotation, and melting point.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.209-213
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• 1995

During the screening of inhibitors of melanin biosynthesis from microbial secondary metabolites, a fungal strain MR-93 which was capable of producing high level of an inhibitor was selected from plant leaf. Based on taxonomic studies, the fungus could be classified as a strain of Trichoderma sp.. The active compound (MR-93D) was purified from the culture broth by Diaion HP-20 column chromatography, ethylacetate extraction, Sephadex LH-20 column chromatography and HPLC. The inhibitor was identified as 4-hydroxy-8-isocyano-l-oxaspiro[4-4]cyclonon-8-en-2- one by spectroscopic methods of UV, $^{1}$H-NMR, ESIMS and IR. MR-93D showed a strong tyrosinase inhibitory activity with 0.03 $\mu$g/m of IC$_{50}$ value. It also inhibited melanin biosynthesis with 35 mm inhibition zone at 30 $\mu$g/paper disc in Streptomyces bikiniensis, a bacterium used as an indicator organism in this work.