• Korean Journal of Veterinary Research
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• v.22 no.1
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• pp.27-29
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• 1982

A bacteriological survey was made for the aerabic Actinonmycetes from the vaginal exudates of apparently healthy dairy cows in Gyeongbug area. One hundred twenty isolated were made from 1,328 cows. Among them 30 isolates (25%) were identified as Nocardia asteriodes, 4 (3.3%) as Nocaradia brasiliensis, and 2 (1.7%) as Nocardia madurae. The remaining 84 isolates (70%) were identified as Streptomyces species.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.3
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• pp.653-660
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• 2016

Snakehead, Channa argus were intraperitoneally infected with Nocardia seriolae. at the concentrations of $1.5{\times}10^7cfu/m{\ell}$ or $1.5{\times}10^8cfu/m{\ell}$. The infected fish were kept in aquaria at $25^{\circ}C$ and $30^{\circ}C$ for 3 weeks. Clinical signs and mortality were monitored daily to evaluate the virulence. All artificially infected fish showed the same clinical sign found in naturally infected fish. All the fish infected with $1.5{\times}10^8cfu/m{\ell}$ of N. seriolae died within 24days. N. seriolae showed higher virulence to snakehead at the temperature $30^{\circ}C$. Internal lesions such as whitish nodules in the infected internal organs were not correlated with mortality but some degenerative changes were observed in all the infected organs within a week. Whitish nodules in the infected organs which are the typical character in nocardial infection was initially found at two weeks after the artificial infection in snakehead.

• KSBB Journal
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• v.11 no.6
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• pp.654-662
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• 1996

Bacterial strains which degrade crude oil were isolated by liquid culture from oil-spilled soil, and four isolates were selected among them. The strain Hl7-1 was finally selected after testing emulsifying activity and oil conversion rate. The strain Hl7-1 was identified as a Nocardia sp. based on the test for morphological, biochemical and physiological characteristics. It appears to be highly specialized for growth on crude oil in minimal salts medium since it showed preference for oil or degradation products as substrates for growth. It was found that it could grow on at least fifteen different hydrocarbons. The optimum cultural and environmental conditions were seeked. Cell growth and emulsification activity as a function of time were also determined. Crude oil degradation and the reduction of product peak was identified by the analysis of remnant oil by gas chromatography after 3 days of cultivation. Approximately 83% of oil were converted into a form no longer extractable by organic solvents.

• Journal of Microbiology and Biotechnology
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• v.33 no.7
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• pp.949-954
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• 2023

Type III polyketide synthase (PKS) found in bacteria is known as 1,3,6,8-tetrahydroxynaphthalene synthase (THNS). Microbial type III PKSs synthesize various compounds that possess crucial biological functions and significant pharmaceutical activities. Based on our sequence analysis, we have identified a putative type III polyketide synthase from Nocardia sp. CS682 was named as ThnA. The role of ThnA, in Nocardia sp. CS682 during the biosynthesis of 1,3,6,8 tetrahydroxynaphthalene(THN), which is the key intermediate of 1-(α-L-(2-O-methyl)-6-deoxymannopyranosyloxy)-3,6,8-trimethoxynaphthalene (IBR-3) was characterized. ThnA utilized five molecules of malonyl-CoA as a starter substrate to generate the polyketide 1,3,6,8-tetrahydroxynaphthalene, which could spontaneously be oxidized to the red flaviolin compound 2,5,7-trihydroxy-1,4-naphthoquinone. The amino acid sequence alignment of ThnA revealed similarities with a previously identified type III PKS and identified Cys¹³⁸, Phe¹⁸⁸, His²⁷⁰, and Asn³⁰³ as four highly conserved active site amino acid residues, as found in other known polyketide synthases. In this study, we report the heterologous expression of the type III polyketide synthase thnA in S. lividans TK24 and the identification of THN production in a mutant strain. We also compared the transcription level of thnA in S. lividans TK24 and S. lividans pIBR25-thnA and found that thnA was only transcribed in the mutant.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.321-327
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• 2015

Nocardia salmonicida is one of the main pathogens of fish nocardiosis. The purpose of this study was to build a loop-mediated isothermal amplification (LAMP) method for the rapid and sensitive detection of N. salmonicida. A set of four primers were designed from the 16S-23S rRNA intergenic spacer region of N. salmonicida, and conditions for LAMP were optimized as incubating all the reagents for 60 min at 64℃. LAMP products were judged with agar gel electrophoresis as well as with the naked eye after the addition of SYBR Green I. Results showed the sensitivity of the LAMP assay was 1.68 × 10³ CFU/ml (16.8 CFU per reaction) and 10-fold higher than that of PCR. The LAMP method was also effectively applied to detect N. salmonicida in diseased fish samples, and it may potentially facilitate the surveillance and early diagnosis of fish nocardiosis.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.439-447
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• 2015

The objective of this study was to isolate and identify the chemical structure of a biosurfactant produced by Nocardia farcinica strain BN26 isolated from soil, and evaluate its in vitro antitumor activity on a panel of human cancer cell lines. Strain BN26 was found to produce glycolipid biosurfactant on n-hexadecane as the sole carbon source. The biosurfactant was purified using medium-pressure liquid chromatography and characterized as trehalose lipid tetraester (THL) by nuclear magnetic resonance spectroscopy and mass spectrometry. Subsequently, the cytotoxic effects of THL on cancer cell lines BV-173, KE-37 (SKW-3), HL-60, HL-60/DOX, and JMSU-1 were evaluated by MTT assay. It was shown that THL exerted concentration-dependent antiproliferative activity against the human tumor cell lines and mediated cell death by the induction of partial oligonucleosomal DNA fragmentation. These findings suggest that THL could be of potential to apply in biomedicine as a therapeutic agent.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.408-412
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• 2003

The purpose of this study was to evaluate the Influence of oil concentration and inoculum size on petroleum biodegradation in soil by Nocardia sp. H17-1, isolated from oil-contaminated soil. To investigate the effect of initial oil concentration on total petroleum hydrocarbon (TPH) degradation, the soil was artificially contaminated with 10, 50 or 100 g of Arabian light oil per kg of soil, respectively. After 50 days, Nocardia sp. H17-1 degraded 78,94 and 53% of the each initial TPH concentration, respectively. Also, it produced 1.35, 4.21, and 5.91 mmol of $CO_2$ per g of soil, respectively. The degradation rate constant (k) of TPH was decreased in proportion to the initial oil concentrations while $CO_2$ production was increased with the concentration. The growth of Nocardia sp. H17-1 was remarkably inhibited when it was inoculated into soil containing 100 g of oil per kg of soil. To evaluate the effect of the inoculum size, the soil was artificially contaminated with 50 g of Arabian light oil per kg of soil, and inoculated with $3${\times}$10^{6}$ , $5${\times}$10^{7}$ , $2${\times}$10^{8}$ cells per g of soil, respectively. After 50 days, the degradation of TPH was remained with similar in all treatment but degradation rate constant (k) and evolved $CO_2$ was increased with increasing the inoculum size.

• Journal of Microbiology and Biotechnology
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• v.1 no.1
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• pp.70-74
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• 1991

The rheological properties of rifamycin B fermentation broth using Nocardia mediterranei were characterized in concomitance with the chemical changes of the fermentation broth. The data were interpreted with various rheological models. As results, it was found that the rheological behaviour at the early growth phases of the culture was the Newtonian fluid, but it was changed to the non-Newtonian fluid (Casson plastic behaviour) at the later phases of the culture. Rheological parameters viz., apparent viscosity ($\mu_a$), yield shear stress ($\tau_o$), and Casson constant ($K_c$) were changed through the fermentation where cell concentrations were changed and mycelia were greatly branched. Those results indicated that cell concentration and cell morphology played important roles to determine the rheological characters.

• Journal of Korean Neurosurgical Society
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• v.49 no.5
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• pp.305-307
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• 2011

We describe here the first case of a concurrent brain abscess caused by Norcardia spp. and semi-invasive pulmonary aspergillosis in an immunocompetent patient. After one year of appropriate antimicrobial therapy and surgical drainage of the brain abscess, the nocardia brain abscess and pulmonary aspergillosis have resolved.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.3 no.3
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• pp.169-175
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• 1999

2,4-Dinitrophenol(DNP) is a metabolic uncoupler that prevents cells from creating energy for growth and it has been suggested that the availability of sodium ions may be important in mitigating the effects of uncouplers. Accordingly, the degradation of DNP was investigated using activated sludge which had been adapted to mineralize DNP. After the acclimation of the activated sludge, the effect of sodium ions on the toxicity of high concentrations(80 to 100mg/L) of DNP was investigated over a sodium ion concentration range of 9.3$\times$10-5 to 94mM. The concentration of sodium ions in the activated sludge mixed liquor seemed to have little effect on the DNP toxicity. However, a lack of sodium in the grwoth media resulted in a reduction of the DNP degradation rate by a bacterial isolate from the activated sludge culture identified as Nocardia asteroides.