• Fisheries and Aquatic Sciences
• /
• v.26 no.3
• /
• pp.234-240
• /
• 2023

Enteromyxum leei has been identified as the causative agent of emaciation disease in a wide range of marine fish hosts. In this study, we aimed to determine the effect of the parasitic infection of Enteromyxum species on starry flounder that were cultured in aquaculture farms of Jeju island in Korea. As the mortality of cultured olive flounder Paralichthys olivaceus because of E. leei infection increased, some fish farms on Jeju island attempted to culture the starry flounder Platichthys stellatus, as an alternative. Myxosporeans with a developmental stage similar to E. leei were found in the intestines of cultured starry flounders. The partial 18S rDNA of myxosporeans showed 100% similarity with E. leei. To reveal the effect of E. leei infection on starry flounder, the intensity of E. leei infection measured using quantitative polymerase chain reaction, and the condition factor (CF) of fish were measured and analyzed statistically. The results showed that high-intensity E. leei infection significantly decreased the CF of the starry flounder. However, the pathogenicity of E. leei to starry flounder is low, considering its mortality and clinical signs.

• Korean Journal of Organic Agriculture
• /
• v.26 no.4
• /
• pp.649-660
• /
• 2018

To control the pepper anthracnose caused by Colletotrichum acutatum, antifungal bacterium strains which was selected among bacterium from natural soil, was tested the antimicrobial activity against various pathogens and its control efficacy on anthracnose disease in the fields. We confirmed that antagonistic activity of CAB13001 strain to pathogens such as Sclerotinia cepivorum, Sclerotinia sclerotium and Botrytis cinerea including Colletotrichum acutatum was remarkable superior with the dual culture method in the artificial medium. In vitro bioassay using the green pepper fruit, CAB13001 strain suppressed the lesion development of Anthracnose disease, and its control value compared to the untreated one was 82.4% on pepper fruit in field test. These results suggested that CAB13001 strain could be a very useful biological control agents to anthracnose disease caused by air born plant pathogens of pepper. By the way, analysis of nucleotide sequence of the gene 16S rDNA, antagonistic bacterium CAB13001 strain used in this study was identified as Burkholderia lata.

• Journal of Life Science
• /
• v.26 no.10
• /
• pp.1163-1168
• /
• 2016

Plant growth-promoting rhizobacteria (PGPR) have gained worldwide importance and acceptance due to their agricultural benefits. These microorganisms are potential tools for sustainable agriculture, with effects on plant growth, biofertilization, induced systemic resistance, and biocontrol of plant pathogens. In this study, four different Pantoea species were isolated from field soil, and their plant growth-promoting characteristics were studied. Based on 16S rDNA gene sequencing analyses, the se were grouped into Pantoea ananatis, Pantoea citrea, Pantoea dispersa, Pantoea vagans and named as Pa1, Pc1, Pd1, Pv1, respectively. All of these strains have their ability for solubilization of insoluble phosphate depending on pH decrease at the range around pH 5 at 1days after inoculation and production of plant hormone indole acetic acid (IAA) with 85.3±16.3 μg/ml of Pa1, 183.9±16.8 μg/ml of Pc1, 28.8±17.3 μg/ml of Pd1 and 114.1±16.5 μg/ml of Pv1, respectively. Pa1, Pc1 and Pd1 also have high activity for production of gibberellin (GA₃) hormone with 331.1±19.2 μg/ml of Pa1, 288.5±16.8 μg/ml of Pc1, 309.2±18.2 μg/ml of Pd1, but Pv1 does not. Furthermore, all these species have significantly promoted the growth of the lettuce seedling plants at the range around 32~37% for fresh weight and 10~15% for shoot length enhancement, so that these microbe could be used as a potential bio-fertilizer agents.

• The Korean Journal of Mycology
• /
• v.50 no.3
• /
• pp.217-224
• /
• 2022

This study aimed to isolated wild yeasts from freshwater in Korea. The strains were identified by using the D1/D2 domains of the 26S rDNA regions. Consequently, six strains were named as Apiotrichum chiropterorum (NNIBRFG36995), A. domesticum (NNIBRFG32938), A. dulcitum (NNIBRFG33144), A. laibachii (NNIBRFG36991), Saprochaete quercus (NNIBRFG33183) and Tausonia pullulans (NNIBRFG33181). These yeasts have not previously been recorded in Korea, this paper is the first report. We were investigated to the morphological and cultural characteristics of these yeasts. All the strains grew well on Yeast extract peptone dextrose (YPD), Potato dextrose (PD), and Yeast mold (YM) media and in temperature range of 15-30℃. A. domesticum (NNIBRFG32938), A. laibachii (NNIBRFG36991) and T. pullulans (NNIBRFG33181) grew even in 20% glucose containing YPD medium, so they had glucose tolerance. A. domesticum (NNIBRFG32938) and A. laibachii (NNIBRFG36991) had salt resistance as growing even in 5% NaCl containing YPD medium.

• Korean Journal of Microbiology
• /
• v.45 no.1
• /
• pp.26-31
• /
• 2009

This study was aimed at the analysis of prokaryote communities in Korean traditional fermented food, jeotgal, and isolation of a novel strain from jeotgal by using culture-dependent and molecular biological approaches. Seventeen kinds of jeotgal were selected on the basis of its origins and sources. The samples were inoculated on 12 kinds of media. 308 isolates were selected randomly by morphological features, and its 16S rRNA gene sequences was amplified by PCR technique with bacteria and archaea specific primers (8F, 21F, and 1492R). The 16S rRNA gene sequences were compared with those in EzTaxon and GenBank databases. DNA-DNA hybridization was performed to identify a novel strain. As a result, the majority of the isolates were lactic acid bacteria (Leuconostoc, Weisella, Lactococcus, Lactobacillus, Carnobacterium, Marinilactibacillus), Bacillus, Pseudomonas, Micrococcus, Brevibacterium, Microbacterium and Kocuria in 17 kinds of jeotgal. The strains belonging to Salinicoccus, Halomonas, Cobetia, Lentibacillus, Paracoccus, and Psychrobacter were isolated as minor ones. Fourteen novel species were identified based on phylogenetic analysis.

• The Korean Journal of Mycology
• /
• v.40 no.2
• /
• pp.86-92
• /
• 2012

Halophyte samples, such as Suaeda japonica, Phragmites australis, Limonium tetragonum, Suaeda maritima were collected from Go-chang salt marsh. Thirty-nine endophytic fungal strains were isolated from the roots of halophytes naturally growing in salt marsh. All endophytic fungal strains isolated were analyzed by internal transcribed spacer (ITS) containing ITS1, 5.8 s and ITS2 region. Endophytic fungal strains belong to eight orders, i.e., Eurotiales (36%), Pleosporales (26%), Hypocreales (18%), Incertae sedis (8%), Glomerellales (5%), Sordariales (2%), Xylariales (2%), and Capnodiales (3%). On genus level, they were composed of Alternaria, Aspergillus, Chaetomium, Cladosporium, Colletotrichum, Coniothyrium, Dothideomycete, Fusarium, Gibberella, Macrophoma, Penicillium, Pestalotiopsis, Phaeosphaeria, Phoma, Pleosporales, Pseudozyma, Talaromyces, and Termitomyces. Of them, Penicillium (26%), Fusarium (13%) of Eurotiales and Hypocreales were predominant.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.6
• /
• pp.929-935
• /
• 2002

The 5-stage biological nutrient removal (BNR) process with step feed system showed a very stable organic carbon and nutrient removal efficiency ($87\%\;COD\,;79\%\;nitrogen,\;and\;87\%$ phosphorus) for an operation period of 2 years. In each stage at the pilot plant, microbial communities, which are important in removing nitrogen and phosphorus, were investigated using fluorescence in-situ hybridization (FISH) and 165 rDNA characterization. All tanks of 5-stage sludge had a similar composition of bacterial communities. The totat cell numbers of each reactor were found to be around $2.36-2.83{\times}10^9$ cells/ml. About $56.5-62.0\%$ of total 4,6-diamidino-2-phenylindol (DAPI) cells were hybridized to the bacterial-specific probe EUB388. Members of ${\beta}$-proteobacteria were the most abundant proteobacterial group, accounting for up to $20.6-26.7\%$. The high G+C Gram-positive bacterial group and Cytophaga-Flexibacter cluster counts were also found to be relatively high. The beta subclass proteobacteria did not accumulate a large amount of polyphosphate. The proportion of phosphorus-accumulating organisms (PAOs) in the total population of the sludge was almost $50\%$ in anoxic-1 tank. The high G+C Gram-positive bacteria and Cytophaga-Flexibacter cluster indicate a key role of denitrifying phosphorus-accumulating organisms (dPAOs). Both groups might be correlated with some other subclass of proteobacteria for enhancing nitrogen and phosphorus removal in this process.

• KSBB Journal
• /
• v.26 no.6
• /
• pp.552-556
• /
• 2011

A novel agar-degrading bacterium mbrc-1 was isolated from seashore of Kyungpo at Gangwon province and cultured in marine broth 2216 medium. Isolated bacterium mbrc-1 was named as Flammeovirga sp. mbrc-1 based on the 16S rDNA sequence. Its agarase showed maximum activity of 923 units/L at pH 7.0 and $45^{\circ}C$ and sustained 90% remaining activity after exposed to $45^{\circ}C$ for 2 hours. The enzyme hydrolyzed agarose to yield neoagarohexaose (18.5%), neoagarotetraose (38%) and neoagarobiose (43.5%), indicating that the enzyme is ${\beta}$-agarase. Thus, isolated bacterium and its ${\beta}$-agarase would be useful for the industrial production of neoagarotetraose and neoagarobiose.

• KSBB Journal
• /
• v.26 no.6
• /
• pp.538-542
• /
• 2011

The research was purposed production of oligosaccharide from alginate hydrolysis the main composition in cell walls of sea weed. We was isolated 252 strains from sea water and mud flat, the highest alginate lyase activity was selected, and identified as Sanguibacter keddieii NC9 by 16S rDNA sequence analysis. In this study was select the sodium alginate concentration, pH, temperature for the production of alginate lyase activity. Alginate lyase activity was confirmed from plate assay with 10% cetylpyridinium chloride. The optimum culture conditions for the production of alginate lyase were sodium alginate 10 g/L, peptone 5 g/L, $40^{\circ}C$, pH 9 and 36 hours incubation time. Sanguibacter keddieii NC9, its alginate lyase would be useful for the production of bioenergy and biofunctional oligosaccharides from sea weed.

• Journal of Microbiology
• /
• v.41 no.2
• /
• pp.73-77
• /
• 2003

Four proteolytic bacteria were isolated and identified from a rotating biological contactor based on Bacillus. The four isolates, Ni 26, 36, 39 and 49 were identified as B. vallismortis, B. subtilis, Aeromonas hydrophila and B. amyioliquefaciens, respectively, based on their biochemical properties and 16S rDNA sequence analyses. The optimal proteolytic activity was observed in the temperature and pH ranges of 40-70$^{\circ}C$ and 8.0-8.5, respectively. The proteolytic activities of all the isolates were partially inhibited by phenylmethylsulfonylfluoride (PMSF), and the isolates Ni 26, Ni 39 and Ni 49 were inhibited by the metalloprotease inhibitor, 1,10-phenanthroline. Zymographic analyses of the culture supernatants revealed the presence of at least two pretenses in all isolates.