• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1449-1459
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• 2015

A novel proteolytic enzyme with fibrinolytic activity, FSP3, was purified from the recently isolated Streptomyces sp. P3, which is a novel bacterial strain isolated from soil. FSP3 was purified to electrophoretic homogeneity by ammonium sulfate precipitation, anion exchange, and gel filtration. FSP3 is considered to be a single peptide chain with a molecular mass of 44 kDa. The maximum activity of the enzyme was observed at 50℃ and pH 6.5, and the enzyme was stable between pH 6 and 8 and below 40℃. In a fibrin plate assay, FSP3 showed more potent fibrinolytic activity than urokinase, which is a clinical thrombolytic agent acting as a plasminogen activitor. The activity was strongly inhibited by the serine protease inhibitor PMSF, indicating that it is a serine protease. Additionally, metal ions showed different effects on the activity. It was significantly suppressed by Mg²⁺ and Ca²⁺ and completely inhibited by Cu²⁺, but slightly enhanced by Fe²⁺. According to LC-MS/MS results, its partial amino acid sequences are significantly dissimilar from those of previously reported fibrinolytic enzymes. The sequence of a DNA fragment encoding FSP3 contained an open reading frame of 1287 base pairs encoding 428 amino acids. FSP3 is a bifunctional enzyme in nature. It hydrolyzes the fibrin directly and activates plasminogen, which may reduce the occurrence of side effects. These results suggest that FSP3 is a novel serine protease with potential applications in thrombolytic therapy.

• Journal of Microbiology and Biotechnology
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• v.24 no.6
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• pp.740-747
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• 2014

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.865-871
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• 2002

A bacterium having strong chitinolytic activity on $0.2\%$ colloidal chitin-containing agar medium was isolated from coastal soil in Korea. Based on the nucleotide sequence of conserved segment of a 165 rRNA gene, the bacterium was identified as Paenibacillus illinoisensis KJA-424. The population of P. illinoisensis KJA-424 and chitinase activity significantly increased for the first 2 days of incubation. On SDS-PACE analysis with $0.01\%$ glycol chitin, three protein bands (63, 54, and 38 kDa) with chitinolytic activity were detected tooted. The effect of P illinoisensis KJA-424 on the egg hatch of root-knot nematode (Meloidogyne incognita) was investigated. After 7 days of incubation with the chitinase-producing P. illinoisensis KJA-424, none of the eggs hatched, whereas a $39.8\%$ egg hatching rate was observed in the water control. Inverted and scanning electron microscopic observations demonstrated that P. illinoisensis KJA-424 deformed and destroyed the eggshell of M. incognita. In conclusion, chitinase-produced by p. illinoisensis KJA-424 caused the lysis of M. incognita eggshell and resulted in the inhibition of egg hatching in vitro.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.921-928
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• 2002

Microorganism producing extracellular CFTase was isolated from soil and designated as Bacillus polymyxa MGL21. The gene encoding the CFTase (cft) from B. polymyxa MGL21 was cloned and sequenced. The ORF of the cf gene was composed of 3,999 nucleotides, encoding a protein (1,333 amino acids) with a predicted molecular mass of 149,375 Da. Sequence analysis indicated that CFTase was divided into five distinct regions. CFTase contained three regions of repeat sequences at the N-terminus and C-terminus. The endo-inulinase region of homology (ERH) of CFTase was similar to that of Pseudomonas mucidolens endo-inulinase ($50\%$ identity, 259 amino acids). Furthermore, CFTase possessed a highly conserved core region, which is considered to be functional for the hydrolysis reaction of inulin. The cft gene was expressed in a His-tagged form in Escherichia coli cells, and the His-tagged CFTase was purified to homogeneity. The optimal temperature and pH for CFTase activity were found to be $50^{\circ}C$ and 9.0, respectively. The enzyme activity was completely inhibited by 10 mM $Ag^+\;and\;Cu^2+$. Thin-layer chromatography analyses indicated that CFTase catalyzed not only the cyclization reaction ut also disproportionation and hydrolysis reactions as well.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.972-978
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• 2002

Streptomyces sp. AD001 is a Gram-positive soil actinomycetes secreting an uncharacterized 2,4-dichlorophenol (DCP) oxidizing enzyme, whose activity is similar to the previously known Actinomycetes lignin-peroxidase (ALiP). This extracellular peroxidase was purified from Streptomyces sp. AD001 as a single protein band on an SDS-PACE by ammonium sulfate fractionation, Q-sepharose, concanavalin A, and Bio-Gel HTP column chromatographies. The molecular mass of the purified peroxidase was determined by SDS-PAGE to be 45.2 kDa, and 49.7 kDa with MALDI-TOF-MS, respectively. The highest level of peroxidase activity was observed at pH 7.5 and $30^{\circ}C$. The amino terminal sequence of the purified peroxidase (G-E-P-E-E-G-N-V-D-G-T-L) showed no significant homologies to my known proteins, suggesting that Streptomyces sp. AD001 may secrete a novel kind of bacterial peroxidase Initial rate kinetic data of the 2,4-DCP oxidation were best modeled with a random-binding bireactant system.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.303-309
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• 2012

Keratinases are of particular interest because of their action on insoluble keratins and generally on a broad range of protein substrates. Alkalophilic and neutrophilic actinomycete strains isolated from different soil samples, rich in keratinaceous substances were screened for keratinolytic activity. An alkalophilic isolate, TBG-S13A5, was found to possess good keratinolytic activity and was able to utilize feather as the sole carbon and nitrogen source. TBG-S13A5 exhibited an off-white aerial mass color with a rectus-flexibilis type of spore chain. The morphological, microscopical and biochemical characters were comparable with that of Streptomyces albidoflavus. Fatty acid methyl ester profiling (FAME) and 16S rDNA sequence analysis confirmed its identity as a strain of S. albidoflavus. Under submerged fermentation conditions, maximum protease production was recorded on the $5^{th}$ day of incubation at $30^{\circ}C$, using basal broth of pH 9.0 with 0.25% (w/v) white chicken feather. This strain could affect feather degradation when the initial pH was 8 and above and maximum protease production was recorded when the initial pH was around 10.5. The effectiveness of the crude enzyme in destaining and leather dehairing were also demonstrated.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.71-76
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• 2002

Soil samples were screened for actinomycete strains capable of producing phospholipase D, and a strain, Streptomyces sp. YU100, showing a high transphosphatidylation activity was isolated. This strain secreted phospholipase D in a culture broth after 12 h of cultivation, and its productivity continued to increase for 36 h of fermentation. In addition, its transphosphatidylation rate of phosphatidylcholine to phosphatidylserine was almost $68\%$ within 1 h. The morphological and chemotaxonomical characteristics showed that this strain could be classified as a number of the Streptomycetaceae family, particularly due to the spiral form of its spore chain consisting of 60-70 smooth spores $(0.75{\times}1.0{\mu}m$) on an aerial mycelium, FA-2c type of fatty acid profile in the cell wall, and LL-DAP component in the cell wall peptidoglycan. A phylogenetic analysis of the 16S rDNA provided a clue that the strain YU100 was actually a member of the genus Streptomyces, because the determined sequence exhibited a higher homology with Streptomyes sp. ASB27, S. peucetius JCM9920, and S. griseus ATCC10137. A dendrogram based on the 16S rDNA sequences also showed a phylogenetic relationship between the strain YU100 and these strains. However, the strain YU100 has not yet been assigned to a particular species, because of absence of any other classified species with a high matching score.

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.61-63
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• 2016

Sclerotium rot disease on cowpea (Vigna sinensis King) was observed in the exhibition field of Gyeongsangnam-do Agricultural Research and Extension Services in September 2015. Lesions were covered by white mycelial mats, and numerous sclerotia were formed on the stem near the soil line. The sclerotia were globoid in shape, 1~3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on potato dextrose agar (PDA) was $30^{\circ}C$, with the hyphal width of $4{\sim}8{\mu}m$. For molecular identification, the complete internal transcribed spacer (ITS) rDNA region of the causal fungus was sequenced and analyzed. Based on the mycological characteristics, ITS rDNA sequence analysis, and pathogenicity test, this fungus was identified as Sclerotium rolfsii. This is the first report of sclerotium rot on cowpea caused by S. rolfsii in Korea.

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.16-22
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• 2016

Five islands (Sinjindo, Mado, Daenanjido, Wonsando, and Sapsido) and the coastal area (Muchangpo) in Chungnam, Korea, were selected to determine the diversity of arbuscular mycorrhizal (AM) fungi. Soil-inhabiting AM fungi were isolated and identified on the basis of morphological characteristics and sequence analyses of 18s rDNA. The differences in the fungal community structures were compared among sites. As a result, 24 species of AM fungi were identified, of which two species of AM fungi, Acaulospora brasiliensis and Redeckera fulvum, were isolated for the first time in Korea. This study revealed that AM fungal spore abundance was low and the genus Acaulospora was dominant in most of the islands. AM fungal community structures in five Islands were highly similar. However, the coastal area, Muchangpo, had different AM fungal community structure from the islands.

• Journal of Species Research
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• v.6 no.1
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• pp.1-14
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• 2017

As a subset study to discover indigenous prokaryotic species in Korea in 2014, a total of 34 bacterial strains assigned to the phylum Actinobacteria were isolated from various environmental samples collected from activate sludge, biotite, freshwater, gut of marine organisms, mud flat, sediment, soil, spent mushroom compost and sea water. On the basis of high 16S rRNA gene sequence similarity and a tight phylogenetic association with the closest species, it was revealed that each strain was assigned to independent and previously described bacterial species, with the exception of one isolate. There is no official report that these 34 species included in the phylum Actinobacteria have been described in Korea: 6 species of 5 genera in the order Corynebacteriales, 1 species of 1 genus in the order Frankiales, 2 species of 2 genera in the Micromonosporales, 14 species of 10 genera in Micrococcales, 2 species of 2 genera in the Propionibacteriales, 1 species of 1 genus in the Pseudonocardiales, 4 species of 2 genera in the Streptomycetales, 2 species of 2 genera in the Streptosporangiales and 1 species of 1 genus in the Solirubrobacterales. Gram reaction, cell and colony morphology, pigmentation, physiological characteristics, isolation sources and strain IDs are described in the section of species description.