• Korean Journal of Microbiology
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• v.46 no.3
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• pp.255-261
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• 2010

The bacterial community structure associated with two marine sponges, Hyrtios sp. 604 and Callyspongia sp. 612 collected from the South Pacific Ocean were analyzed by 16S rDNA-denaturing gradient gel electrophoresis (DGGE). The phylogenetic analysis showed that the bacterial community associated with Hyrtios sp. 604 contained diverse bacterial groups such as Chloroflexi, Firmicutes, Cyanobacteria, Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Acidobacteria. Callyspongia sp. 612 harbored Chloroflexi, Cyanobacteria, Alphaproteobacteria, and Gammaproteobacteria. Hyrtios sp. 604 belonging to genus Hyrtios known to produce natural products showed greater bacterial diversity than Callyspongia sp. 612. Phylum Actinobacteria was shown to be one of dominant bacterial groups in Hyrtios sp. 604. Although the same phyla of bacteria were found in both sponge species, the spongeassociated predominant bacterial groups differed between the two sponges with different chemical characteristics from the same geographical location. Uncultured bacteria represented over 90% of the bacteria diversity present in all bacterial communities of the sponges.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.31-38
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• 2015

The bacterial community structures of two marine sponges, Cinachyrella sp. and Plakortis sp., collected from Chuuk in the South Pacific in February 2012 were analyzed by PCR-DGGE (Denaturing Gradient Gel Electrophoresis) fingerprinting. After isolation of the total genomic DNAs from the sponges, the V3 regions of the 16S rRNA genes were amplified and subjected to DGGE profiling. The two species of sponges displayed different DGGE band patterns. The sequences derived from the DGGE bands revealed 85-100% similarities to known bacterial species in the public database. The bacterial community of Cinachyrella sp. was composed of 6 classes: Actinobacteria, Bacteroidetes, Chloroflexi, and Proteobacteria (Alpha-, Gamma-, Delta-). The bacterial community of Plakortis sp. included 7 classes: Actinobacteria, Chloroflexi, Firmicutes, Spirochaetes, and Proteobacteria (Alpha-, Gamma-, Delta-). Though Actinobacteria, Chloroflexi and Proteobacteria were commonly found in both sponges, the predominant bacterial communities differed between the two. Namely, the predominant bacterial groups in Cinachyrella sp. and Plakortis sp. were Proteobacteria and Chloroflexi, respectively. The sponge-associated bacteria are sponge host-specific, as each of the tested sponges from the same geographical location had different predominant bacterial diversity.

• Korean Journal of Organic Agriculture
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• v.12 no.1
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• pp.101-114
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• 2004

This study was carried out to clarify the effects of antagonistic microorganism, Bacillus sp. JC181 isolated from the greenhouse soil grown cucumber plants on the growth inhibition of plant pathogen, fusarium wilt (Fusarium oxysporum) occurred in cucumber plants in greenhouse. Antagonistic bacterial strains were isolated and were investigated into the antifungal activity of the antagonistic microorganism against fusarium wilt. Screened fourteen bacterial strains which strongly inhibited F. oxysporum were isolated from thc greenhouse soil grown cucumber plants, and the best antagonistic bacterial strain designated as JC181, was finally selected. Antagonistic bacterial strain JC181 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. Bacillus sp. JC181 showed 58.2% of antifungal activity against the plant pathogen growth of F. oxysporum. By the bacterialization of culture broth and heated filtrates of culture broth, Bacterial strain, Bacillus sp. JC181. showed 91.2% and 260% of antifungal activity against F. oxysporum, respectivrly.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.177-182
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• 2010

The bacterial community structure of two marine sponges, Spirastrella abata and Cinachyrella sp. collected from Jeju Island, in April 2009, was analyzed by 16S rDNA-denaturing gradient gel electrophoresis (DGGE). DGGE banding patterns indicated 8 and 7 bands for Spirastrella abata and Cinachyrella sp., respectively. Comparative sequence analysis of variable DGGE bands revealed from 92% to 100% similarity to the known published sequences. The bacterial groups associated with Spirastrella abata were Alphaproteobacteria and Deltaproteobacteria. The bacterial community of Cinachyrella sp. consisted of Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria. Alphaproteobacteria was common and predominant in both the sponge species. Deltaproteobacteria was found only in Spirastrella abata while Actinobacteria and Gammaproteobacteria were found only in Cinachyrella sp. The results revealed that though the common bacterial group was found in both the sponges, the bacterial community profiles differed between the two sponge species obtained from the same geographical location.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.406-411
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• 2001

In a bacterial denitrification test with Pseudomonas sp. and anaerobic consortium, more nitrates and less substrate were consumed but less metabolic nitrite was produced under an anaerobic $H_2$ condition rather than under $N_2$ condition. In a bioelectrochemical denitrification test with the same organisms, the electrochemically reduced neutral red was confirmed to be a substitute electron donor and a reducing power like $H_2$. The biocatalytic activity of membrane-free bacterial extract, membrane fraction, and intact cell for bioelectrochemical denitrification was measured using cyclic voltammetry. When neutral red was used as an electron mediator, the electron transfer from electrode to electron acceptor (nitrate) via neutral red was not observed in the cyclic voltammogram with the membrane-free bacterial extract, but it was confirmed to gradually increase in proportion to the concentration of nitrate in that of the membrane fraction and the intact cell of Pseudomonas sp.

• Korean Journal of Organic Agriculture
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• v.13 no.2
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• pp.161-173
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• 2005

This study was carried out to clarify the effects of antifungal bacterial strains isolated from the greenhouse soil grown strawberry plants on the growth inhibition of plant pathogen, gray mold (Botrytis cinerea) infected in strawberry plants in Damyang and Jangheung districts. Antagonistic bacterial strains were isolated and investigated into the antagonistic activity against gray mold. Screened ten bacterial strains which strongly inhibited Botrytis cinerea were isolated from the greenhouse grown strawberry plants, and the best antifungal microorganism designated as SB 143 was finally selected. Antifungal bacterial strain SB 143 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. Bacillus sp. SB 143 showed 59.4% of antifungal activity against Botrytis cinerea. By the bacterialization of culture broth and heated filtrates of culture broth, Bacillus sp. SB 143 showed 93.1% and 32.1% of antagonistic activity against Botrytis cinerea.

• Korean Journal of Organic Agriculture
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• v.12 no.2
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• pp.183-196
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• 2004

This study was carried out to screen and select the effects of antifungal bacterial strains which inhibit the growth of plant pathogen, Fusarium oxysporum(fusarium wilt) occurred in carnation plants in greenhouse. We isolated an effective bacterial strains and investigated into the antifungal activity of the antagonistic microorganism and it's identification. Twenty bacterial strains which strongly inhibited Fusarium oxysporum were isolated from roots of carnation plants and the soil in greenhouse, and the best antifungal bacteria designated as C121, was finally selected. Antagonistic bacterial strain, C121 was identified to be the genus Bacillus sp. based on the morphological, biochemical and cultural characterizations. The Bacillus sp. C121 showed 58.1% of antifungal activity against the growth of Fusarium oxysporum. By the bacterialization of the cultural broth and the heat bacterialization culture filtrate of it, Bacillus sp. C121 was shown 92.1% and 21.0% of antifungal activity, respectively.

• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.20-32
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• 2021

BACKGROUND: Bacterial shot hole of stone fruits is a seriuos plant disease caused by Xanthomonas arboricola pv. pruni (Xap). Techniques to control the disease are required. In this study, microorganisms with antibacterial activity were isolated to develop as a microbial agent against the bacterial shot hole. METHODS AND RESULTS: An isolate with the strongest activity among the isolates was identified as Streptomyces avidinii based on 16S rRNA gene sequence analysis and designated Streptomyces sp. J46. J46 showed suppression of bacterial leaf spot with a control value of 90% at 10 times-diluted cell free supernatant. To investigate antibacterial metabolites produced by J46, the supernatant of J46 was extracted with organic solvents, and the extracts were subjected to chromatography works. Antibacterial metabolites were not extractable with organic solvents. Both reverse and normal phase techniques were not successful because the metabolites were extremely water soluble. The antibacterial metabolites were not volatiles but protein compounds based on hydrolysis enzyme treatment. CONCLUSION: Our study suggests that Streptomyces sp. J46 may be a potential as an microbial agent against bacterial shot hole. Further study to identify the metabolites is required in more detail.

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.39-47
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• 2014

Sponge in Lake Baikal is an unique organism. Microorganisms in sponges are assumed as precious resources for bioactive materials. For understanding the bacterial community in Baikalian sponges by cultivation, 92 strains of bacteria were isolated from lake water and 2 species of sponges, Baikalospongia sp. and Lubomirskia sp., Thirty five bacterial strains are isolated from ambient water near the sponge, 27 bacterial strains from Baikalospongia sp., 30 bacterial strains from Lubomirskia sp.. As a result, 78.3% and 57.6% of isolated bacterial strains has amylase and protease activity respectively, while strains with cellulose and lipase activities were 38.0% and 34.8%. By 16S rRNA sequence analysis of selected strains, 13 strains which were isolated from Baikalospongia sp. were belong to Pseudomonas spp.. Whereas, 14 strains which were isolated from Lubomirskia sp. were Pseudomonas spp., Buttiauxella agrestis, Pseudomonas fluorescens, Yersinia ruckeri, Bacillus spp., Paenibacillus spp., Bacillus thuringiensis, Bacillus simplex, Brevibacterium spp., Acinetobacter lwoffii. In culture media, Pseudomonas spp. dominance was supposed that according to allelophathy.

• Korean Journal of Microbiology
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• v.12 no.1
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• pp.1-14
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• 1974

The strain of Peptostreptococcus sp. S99 used in this study was isolated from the serous discharge of omphalitis of a 6 days old icteric male infant at the Clinical Laboratory of Microbiology, Seoul National University Hospital on June 9, 1973. The purpose of this study is to clarify the commensalism between Peptostreptococcus sp. and the human bacterial flora isolated from clinical specimens with special references to pH.