• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.235-244
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• 2009

This experiment was conducted to develop a new silage inoculant for barley at forage analysis laboratory, Grassland and Forages Division, National Institute of Animal Science, RDA from 2000 to 2002. Barley is very important crop in Korea. The great part of them is utilized as forage. Generally, it contains a lot of grains that are feed of animal, especially whole crop silage in ruminant. Efficient lactic acid bacteria were isolated from good barley silage by plating MRS agar containing 0.02% sodium azide, and assessed by growing and acid producing ability in MRS broth. Four lactic acid bacteria were selected, and were found to be Gram positive, rods and catalase negative and were identified to be Lactobacillus plantarum on the basis of the biochemical characteristics and utilization of substrates. Barley was ensiled at dough stage following treatment with four lactic acid bacteria, commercial inoculant, and no additive (control). After 2 months, B2-2 bacteria inoculated silage was lower pH and higher lactic acid content than others treatments. The Flieg's score and grade of B2-2 bacteria treated silage were higher than commercial inoculant. According to this experiment, Lactobacillus plantarum B2-2 (NLRI 201) was recommendable for good silage inoculant of whole crop barley silage.

• Parasites, Hosts and Diseases
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• v.38 no.2
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• pp.51-57
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• 2000

Follow-up studies have been conducted every three years on the endemicity of Gymnophalloides seoi infection in a small coastal village of Chollanam-do (Province), Korea, since it was first known as an endemic area in 1994. Special attention was given to its egg laying capacity in the human host. In fecal examinations, the overall helminth egg and/or cyst positive rate was 78.7% (74/94) in 1997 and 76.6% (82/107) in 2000. Among them G. seoi eggs showed the highest rate; 71.3% (67/94) in 1997 and 72.0% (77/107) in 2000. The average number of eggs per gram of feces (EPG) was 1,015 in 1997, while a reduced rate of 353 was observed in 2000. In 1997, total of 320,677 adult flukes of G. seoi (av. 10,344/person, 94-69,125 in range) were collected from the diarrheic stools of 31 treated patients. The EPG/worm obtained from 21 cases ranged from 0.04 to 0.77 (av. 0.23), suggesting density-dependent constraints on the worm fecundity. The relationship between the worm burden (X) and EPG/worm (Y) can be expressed as $Y=0.42{\cdot}e{\cdot}^{-l.2x}(r=0.49)$. The results showed that G. seoi infection is persistently endemic in this village.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.77-84
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• 1987

The population of actinomycetes in paddy soils, with hay compost and inorganic fertilizer had been applied respectively was investigated. Actinomycetes were isolated by using selective medium and the population densities of actinomycetes in paddy soil was examined. The population of actinomycetes were reached at a range from $2.1{\times}10^6$ to $7.4{\times}10^7$ per gram of the soil. The composition of actinomycetes flora changed considerably after hay compost applied. The significant positive correlations between the organic matter content in paddy soil and the actinomycetes populations were given at 1.38 to 2.69 level. According to the result of several morphological observation, similar strains isolated were classified into 21 groups. More detailed taxonomic characterization were carried out on the isolated strains. Therefore, 15 groups of Streptomyces and 6 groups of non-Streptomyces were classified into actinomycetes isolates, percentage of streptomyces and non-Streptomyces strains were 87.2% and 12.8% in the isolated 250 actinomycetes strains respectively. Streptomyces with sporophore of the spiral chain form accounted for 80% of all the Streptomyces isolates. Surface morphology of spores were determined with the electron microscope, three species have a spiny surface, and 13 strains have a smooth spore surface.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.47-53
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• 2007

The DY1 strain of Gram-positive, rod-shaped bacteria was isolated from the soil sample collected from Daeam mountain, Korea. The culture filtrate of DY1 strain showed a broad spectrum of antimicrobial activity on various pathogenic and food poisoning enteric bacterial species tested in vitro. It showed significant growth-inhibitory effect on Salmonella enterica sp., Shigella sp., pathogenic Escherichia coli, Vibrio cholerae, Vibrio parahemolyticus, and Yersinia enterocolitica. For the identification of the DY1 strain, morphological, biochemical and molecular phylogenetic approaches were performed. The DY1 strain was found to be a member of the genus Paenibacillus on the basis of morphological and biochemical analyses. The 16S rDNA of DY1 showed the highest pairwise identity with Paenibacillus polymyxa with 99.79% (1,413 bp/1,416 bp). The antimicrobial entity from DY1 looked different from preciously reported ones and seems to have a great potential to be further studied as a candidate of new antibiotics to control multi-drug resistant pathogens.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.218-224
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• 2011

Lactic acid bacteria (LAB) OA18 was isolated from yogurt prepared by using Kefir Grain as a starter. The OA18 strain was a Gram-positive, cocci-type bacterium, and able to grow anaerobically with $CO_2$ production. The OA18 strain grew well on MRS broth supplemented with 50 mM arginine at $30-37^{\circ}C$ and pH of 7.0-9.0. The optimum temperature and pH for growth are $37^{\circ}C$ and pH 7.0. The isolate fermented ribose, D-glucose, cellobiose, D-trehalose, but not L-xylose, D-melibiose, and inositol. The 16S rRNA gene sequence of the isolate showed 99.8% homology with the Enterococcus faecalis 16S rRNA gene (Access no. AB012212). Based on the biochemical characteristics and 16S rRNA gene sequence analysis data, it was identified and named as E. faecalis OA18. The E. faecalis OA18 strain showed a high ornithine-producing capacity in the presence of arginine and also showed an antimicrobial activity against Streptomyces strains such as Streptomyces coelicolor subsp. Flavus, S. coeruleorubidus, S. coeruleoaurantiacus, S. coelicolor, S. coeruleoprunus. The cell growth of E. faecalis OA18 strain was maintained in MRS broth with a NaCl concentration of 0-7%.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.56-65
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• 2011

Culture-independent microscopic observations and 16S rDNA analyses were applied to describe the bacterial community inherent to the biofilm structure of the RABC (Rotating Activated Bacillus Contactors) process for swine butchery wastewater treatment. The ratios of Gram-positive bacterial counts to total bacterial counts of the RABC process were significantly increased in the last aeration tank as well as returned sludge, while those of the existing A2O (Anaerobic-Anoxic-Oxic) process maintained constant from aeration tanks to returned sludge. Totally nine phyla were recovered by 16S rDNA analysis, two of which were major groups: the Proteobacteria (64.1%) and the Actinobacteria (18.4%). The third major group was the endospore-forming Firmicutes (5.4%). The remaining six minor groups are the Bacteroidetes (3.3%), the Chlorobi (2.2%), the Nitrospirae (1.1%), the Chlorofleix (1.1%), the Acidobacteria (1.1%), and the Fusobacteria (1.1%). The ratio of endospore-forming bacteria was 19.4%, which was composed of the members of the Firmicutes phylum (5.4%) and the Intrasporangiaceae family (14.0%) of the Actinobacteria phylum. Nitrifying and denitrifying related- and phosphorus accumulating related-sequences were composed of 6.5% and 5.4% of total community, respectively, these could mean the high capacity of the RABC process to remove odor compounds and reduce eutrophication by efficient removing inorganic nutrients.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.63-67
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• 2010

Proteases catalyze hydrolytic cleavage of a peptide bond between amino acids and occupy pivotal positions in application in physiological and commercial fields. During the screening for novel bacteria producing extracellular protease, two bacterial strains, WD12 and WD32, were isolated from rotten trees and they made clear zone on LB plates supplemented with 1% skim milk. The similarities of 16S rRNA gene sequence of either WD12 or WD32 to GenBank database showed the highest to Pseuoxanthomonas mexicana as 97.8 and 99.8%, respectively. Phylogenetic analysis showed that both isolated was located within the cluster comprising P. mexicana and P. japonesis. WD12 and WD32 were catalase- and oxidase-positive, Gram-negative rod strains. In case of WD12, it could assimilate malate, but could not assimilate D-mannose, which were different characteristics from P. mexicana. Both Pseuoxanthomonas sp. WD12 and WD32 optimally produced extracellular protease at $35-37^{\circ}C$, and maximal activity showed as 656 unit/ml and 267 unit/ml, respectively.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.90-94
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• 2013

A new Bacillus strain designated as MP56 producing antimicrobial substance has been isolated from the mud flat of Korea. The strain MP56 was found to exhibit broad spectrum of antimicrobial activity against Gram-positive pathogenic microorganisms and MDR (multi drug resistant) strains. The 16S rRNA sequence revealed that the MP56 was closely related to Bacillus subtilis with 99.93% homology. The optimal medium composition for production of antimicrobial substance in the B. subtilis MP56 were 1% mannitol, 1% oat meal, 0.01% $CaCl_2$. Antimicrobial activity of the culture broth against different pathogenic strains was assessed using the antimicrobial spectrum. The result suggests that Bacillus strain MP56 produces high quality antimicrobial substance that might be very useful to control varieties of pathogenic microbial growth.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.417-425
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• 2019

Biocontrol agents (BCAs) are widely used to protect plants from diverse biotic and abiotic stresses in agricultural and ecological fields. Among the various microbes, many subspecies of the gram-positive genus, Bacillus, have been successfully industrialized as eco-friendly biological pesticides and fertilizers. In the current study, we demonstrated that Bacillus thuringiensis C25 exhibited antagonistic effects on the mycelial growth of Rosellinia necatrix, a fungal phytopathogen. Scanning electron microscopy analysis revealed that B. thuringiensis C25 degraded the cell wall structures of R. necatrix mycelia. In the functional genomic analysis of B. thuringiensis C25, we annotated 5,683 genes and selected the gene sets that potentially encoded fungal cell wall degrading enzymes (CWDEs). The growth inhibition effects on R. necatrix were highly correlated with the transcriptional activity of the mycelial cell wall degrading genes of B. thuringiensis C25. The transcript levels of CWDEs, including CshiA, B, and Glycos_transf_2 genes in B. thuringiensis C25, were enhanced following co-cultivation with R. necatrix. In conclusion, our study suggested that B. thuringiensis C25 could serve as a suitable candidate for controlling R. necatrix and could facilitate elucidating the mechanisms underlying the antifungal activities of BCAs against phytopathogens.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.136-140
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• 1986

The change of cell counts of Vibrio parahaemolyticus in fish muscle by the storage time and temperature was examined to get basic informations for precautionary steps against food poisoning of slices of raw fish (sashimi). There fore, we inoculated fish homogenate of oceanic bonito (Katsuwonus pelamis), yellow tail (Seriola quinqueradiata) with Kanagawa positive Vibrio parahaemolyticus and stored it at $30^{\circ}C,\;18^{\circ}C,\;4^{\circ}C\;and\;-20^{\circ}C$ for 24 hours. The number of the Vibrio parahaemolyticus upon fish homogenate stored at $30^{\circ}C\;and\;18^{\circ}C$ decreased for the first two hours and increased thereafter. When the fish homogenates inoculated with Vibrio parahaemolyticus at about $10^3$ per gram were stored at $18^{\circ}C\;and\;30^{\circ}C$ for 10 hours, the cell numbers increased about 10 times and 1,000 times initial cell numbers, respectively. The survival rate of Vibrio parahaemolyticus was about $20\%$, when the inoculated fish homogenates were stored at $-20^{\circ}C$ for 24 hours. Vibrio parahaemolyticus inoculated in fish homogenates was decreased by about $10\%$ of initial cell numbers by the storage at $4^{\circ}C$ for 4 hours and it was decreased by about $50\%$ after 24 hours storage of the samples at the same temperature. The decreasing rate of inoculated Vibrio parahaemolyticus in fresh fish muscle homogenate was higher than that in frozen fish muscle homogenate during the storage time at a refrigerator.