• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1577-1584
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• 2010

In total, 140 halotolerant bacterial strains were isolated from both the soil of barren fields and the rhizosphere of six naturally growing halophytic plants in the vicinity of the Yellow Sea, near the city of Incheon in the Republic of Korea. All of these strains were characterized for multiple plant growth promoting traits, such as the production of indole acetic acid (IAA), nitrogen fixation, phosphorus (P) and zinc (Zn) solubilization, thiosulfate ($S_2O_3$) oxidation, the production of ammonia ($NH_3$), and the production of extracellular hydrolytic enzymes such as protease, chitinase, pectinase, cellulase, and lipase under in vitro conditions. From the original 140 strains tested, on the basis of the latter tests for plant growth promotional activity, 36 were selected for further examination. These 36 halotolerant bacterial strains were then tested for 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. Twenty-five of these were found to be positive, and to be exhibiting significantly varying levels of activity. 16S rRNA gene sequencing analyses of the 36 halotolerant strains showed that they belong to 10 different bacterial genera: Bacillus, Brevibacterium, Planococcus, Zhihengliuella, Halomonas, Exiguobacterium, Oceanimonas, Corynebacterium, Arthrobacter, and Micrococcus. Inoculation of the 14 halotolerant bacterial strains to ameliorate salt stress (150 mM NaCl) in canola plants produced an increase in root length of between 5.2% and 47.8%, and dry weight of between 16.2% and 43%, in comparison with the uninoculated positive controls. In particular, three of the bacteria, Brevibacterium epidermidis RS15, Micrococcus yunnanensis RS222, and Bacillus aryabhattai RS341, all showed more than 40% increase in root elongation and dry weight when compared with uninoculated salt-stressed canola seedlings. These results indicate that certain halotolerant bacteria, isolated from coastal soils, have a real potential to enhance plant growth under saline stress, through the reduction of ethylene production via ACC deaminase activity.

• Korean Journal of Veterinary Service
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• v.39 no.3
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• pp.167-174
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• 2016

In this study, we analyzed for the changes of low organic compounds during 4 weeks incubation though inoculation of harmful microorganisms on commercial feed. Two percent of overnight cultures of Exiguobacterium acetylicum, Acinetobacter calcoaceticus, Aspergillus flavus and Fusarium graminearum were inoculated in feed, respectively. After adjusting moisture level to 50% for the promotion of feed spoilage, pH was decreased to 4.58~5.03 and microorganism was ranged to $6{\sim}10log_{10}CFU/g$. The compounds were compare between aflatoxin G1 producing feeds and aflatoxin G1 non-producing feeds. Aflatoxins G1 were detected by the immunoaffinity column clean-up method with HPLC-FLD, and were confirmed in samples incoulated by Aspergillus flavus and Acinetobacter calcoaceticus. Koiganal II, cyclohexanol and butadien-one were detected from samples (the non-sterilized inoculated feed) by Aspergillus flavus and Acinetobacter calcoaceticus. Respectively as aflatoxin G1 pre-detected substance, Koiganal II, cyclohexanol and butadien-one may be useful substance for the pre-detection of aflatoxin G1.

• Korean Journal of Plant Resources
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• v.18 no.1
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• pp.198-206
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• 2005

This study was carried out to identify bacterial strains adhered to domestic pet dog hair and to identify antibacterial extracts from natural compounds. A total of 76 strains were isolated from dog hair. The most common species isolated was Staphylococcus spp. (41 isolates), followed by Micrococcus spp. (21 isolates), Enterococcus spp. (8 isolates), Bacillus sup. (3 isolates), Exiguobacterium sup. (2 isolates), Shigella spp. (1 isolate) and Zoogloea spp. (1 isolate). These results suggested that dog hair could be a source of bacterial contamination to human. The susceptibility of isolates to antibiotics and antibacterial activities of the natural compounds were examined by disk diffusion method. Water and ethanol extract from Scutellaria baicalensis revealed high antibacterial activities against Staphylococcus, Micrococcus, Enterococcus and Shigella. Our results suggest that the extract of Scutellaria baicalensis can be used a antibacterial agent against the antibiotic-resistant microorganisms.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.625-636
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• 2011

Cold-adapted bacteria survive in extremely cold temperature conditions and exhibit various mechanisms of adaptation to sustain their regular metabolic functions. These adaptations include several physiological and metabolic changes that assist growth in a myriad of ways. Successfully sensing of the drop in temperature in these bacteria is followed by responses which include changes in the outer cell membrane to changes in the central nucleoid of the cell. Their survival is facilitated through many ways such as synthesis of cryoprotectants, cold acclimation proteins, cold shock proteins, RNA degradosomes, Antifreeze proteins and ice nucleators. Agricultural productivity in cereals and legumes under low temperature is influenced by several cold adopted bacteria including Pseudomonas, Acinetobacter, Burkholderia, Exiguobacterium, Pantoea, Rahnella, Rhodococcus and Serratia. They use plant growth promotion mechanisms including production of IAA, HCN, and ACC deaminase, phosphate solublization and biocontrol against plant pathogens such as Alternaria, Fusarium, Sclerotium, Rhizoctonia and Pythium.