• Title/Summary/Keyword: environmental microbiology

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Biochemical Characterization of $\small{L}$-Asparaginase in NaCl-Tolerant Staphylococcus sp. OJ82 Isolated from Fermented Seafood

  • Han, Sangwon;Jung, Jaejoon;Park, Woojun
    • Journal of Microbiology and Biotechnology
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    • v.24 no.8
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    • pp.1096-1104
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    • 2014
  • $\small{L}$-Asparaginase from gram-positive bacteria has been poorly explored. We conducted recombinant overexpression and purification of $\small{L}$-asparaginase from Staphylococcus sp. OJ82 (SoAsn) isolated from Korean fermented seafood to evaluate its biotechnological potential as an antileukemic agent. SoAsn was expressed in Escherichia coli BL21 (DE3) with an estimated molecular mass of 37.5 kDa, determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Consistent with asparaginases in gram-negative bacteria, size-exclusion chromatography determined SoAsn as a homodimer. Interestingly, the optimal temperature of SoAsn was $37^{\circ}C$ and over 90% of activity was retained between $37^{\circ}C$ and $50^{\circ}C$, and its thermal stability range was narrower than that of commercial E. coli $\small{L}$-asparaginase (EcAsn). Both SoAsn and EcAsn were active between pH 9 and 10, although their overall pH-dependent enzyme activities were slightly different. The $K_m$ value of SoAsn was 2.2 mM, which is higher than that of EcAsn. Among eight metals tested for enzyme activity, cobalt and magnesium greatly enhanced the SoAsn and EcAsn activity, respectively. Interestingly, SoAsn retained more than 60% of its activity under 2 M NaCl condition, but the activity of EcAsn was reduced to 48%. Overall, the biochemical characteristics of SoAsn were similar to those of EcAsn, but its kinetics, cofactor requirements, and NaCl tolerance differed from those of EcAsn.

Antibiotic Susceptibility Pattern and Molecular Typing By PCR-RAPD Analysis of Clinical and Environmental Isolates of Pseudomonas aeruginosa

  • Oluborode, O.B.;Smith, S.I.;Seriki, T.A.;Fowora, M.;Ajayi, A.;Coker, A.O.
    • Microbiology and Biotechnology Letters
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    • v.46 no.4
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    • pp.434-437
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    • 2018
  • Pseudomonas aeruginosa accounts for a significant proportion of nosocomial infections. This study examined the antimicrobial susceptibility pattern and clonal relatedness of P. aeruginosa isolates of clinical and environmental origin. These isolates displayed susceptibility to levofloxacin, ciprofloxacin, gentamicin, imipenem, and ceftazidime of 65.0%, 62.5%, 90.0%, 100%, and 85%, respectively. PCR-RAPD analysis of the P. aeruginosa isolates revealed marked variation. No correlation was observed between the antibiotic resistance profiles and the DNA typing patterns.

Glycolipid Biosurfactants Produced by Pseudomonas aeruginosa D2D2 from Diesel-Contaminated Soil

  • MOON, HYE-JOON;YOUNG-KUONG LIM;HEE-SIK KIM;DAE-YOUNG KWON;WOOK-JIN CHUNG
    • Journal of Microbiology and Biotechnology
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    • v.12 no.3
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    • pp.371-376
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    • 2002
  • A biosurfactant-producing bacterial strain was selected from diesel-contaminated soil by measuring the oil-film collapsing activity and identified as Pseudomonas aeruginosa D2D2. When glucose and olive oil were used as carbon sources, 11.46 g/1 of biosurfactant was obtained. Based on TLC analysis, the biosurfactant produced from P. aeruginosa D2D2 was identified as a glycolipid, consisting of two types of biosurfactants (Type I and Type II). The purified glycolipid reduced the surface tension of the culture from 72 dyne/cm to 27 dyne/cm. The hydrophilic and hydrophobic moiety of the biosurfactant were rhamnose and ${\beta}$-hydroxydecanoic acid, as determined by FAB-MS and NMR analyses, respectively.

Seven New Records of Penicillium Species Belonging to Section Lanata-Divaricata in Korea

  • Pangging, Monmi;Nguyen, Thuong T.T.;Lee, Hyang Burm
    • Mycobiology
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    • v.49 no.4
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    • pp.363-375
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    • 2021
  • Penicillium species are known to be ubiquitous environmental saprophytes. In the survey of diversity of genus Penicillium, seven new records of Penicillium species belonging to section Lanata-Divaricata were isolated from freshwater and soil samples collected from different locations in Korea. Based on morphological characteristics and multilocus phylogenetic analysis of the rDNA internal transcribed spacer region (ITS), β-tubulin (BenA), and calmodulin (CaM) genes, the isolated strains were identified as P. annulatum, P. camponotum, P. echinulonalgiovense, P. globosum, P. limosum, P. onobense, and P. yunnanense, respectively. This study presents detailed phylogenetic analyses and morphological descriptions of these species that contribute to section Lanata-Divaricata in Korea.