• KSBB Journal
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• v.20 no.5 s.94
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• pp.371-375
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• 2005

In the course of our search for compounds effective to multidrug-resistant cancer cells from myxobacteria with the adriamycin-resistant cancer cell line CL02, we found cytotoxic activity against the CL02 cells in culture extract of Sorangium cellulosum JW1045. Activity-guided fractionation of the culture extract led to the isolation of an active principle, chivosazole F, This compound showed high cytotoxic activity against cultured human cancer cells. The $IC_{50}$ values, measured by a SRB assay with different cell lines, ranged from 0.1 to 10 ng/ml. Furthermore chivosazole F was as active against drug-resistant cancer cells CL02 and CP70 as against the corresponding sensitive cells.

• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.10-16
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• 2009

Polymerase chain reactin (PCR) could be a simple way to screen new microbial strains producing useful secondary metabolites if their biosynthetic genes are known and candidate strains to be screened are available. In this study, we have screened two myxobacterial strains, KYC3047 and KYC3076, carrying genes appeared to be biosynthetic genes of soraphen A, a potent antifungal substance, out of 50 cellulose degrading myxobacteria using PCR. The two strains were identified as Sorangium cellulosum based on morphological, physiological, and molecular biological characteristics. Both of the strains produced substances having strong antifungal activities as expected against Candida albicans, a causative agent of candidiasis, and Colletotrichum acutatum, a causative agent of anthracnose on pepper.

• Journal of fish pathology
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• v.5 no.2
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• pp.87-92
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• 1992

Lysozymes were isolated and purified from various organs of cultured flounder by using chitin-coated cellulose column chromatography. The molecular weights of them were compared with each other in 15% SDS-PAGE gels. The result showed that all lysozymes isolated from various organs of flounder had the same molecular weight of about 14000. To clarify the role of lysoryme as a body defence, the antibacterial activities of flounder lysozyme on seven bacterial pathogens, five Gram-negative and two Gram-positive species, were investigated. The lysozyme had substancial antibacterial activity on four strains, two Gram-negative and two Gram-positive species. These suggest that flounder lysozyme plays a role in body defence against both Gram-negative and Gram-positive bacterial pathogens.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.218-223
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• 2004

Myxobacteria are Gram-negative soil bacteria known to be a rich source of potentially useful secondary metabolites. We have isolated 204 strains of bacteriolytic myxobacteria from soil samples collected in Korea and determined their 16S rRNA sequences. Sequence analysis of the partially determined 16S rRNA sequences has suggested that 132 isolates (65% of total isolates) belong to the genus Myxococcus and 59 isolates (29% of total isolates) belong to the genus Corallococcus. Meanwhile, 4 isolates appear to be Archangium spp. and the other 4 isolates appear to be Stigmatella spp. Genera of the remained 5 isolates have not been identified because their 16S rRNA sequences are distantly related to those of known myxobacteria.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.577-587
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• 1989

소의 하부호흡기계 질병을 진단하고자 기침과 비루를 주증상으로 하는 31두의 환우와 임상증상을 나타내지 않는 9두의 소에 5 fr. urinary catheter를 이용한 transtracheal aspiration technique를 적용하고 이 방법의 유용성 및 분리된 병원성 세균과 세포상을 임상증상과 관련하여 조사하여 다음과 같은 결과를 얻었다. Transtracheal aspiration technique은 구강내 정상상재균에 오염되지 않은 가검물을 하부호흡기로부터 채취하는데 호흡장애와 합병증을 유발하지 않았다. 총 40두로부터 분리한 세균중 Pasteurella multocida가 48.7%로 가장 많이 분리되었으며 점액 화농성 염증이 40%로 가장 많이 나타났다. 심한 임상증상을 보인 소중 점액화농성 염증이 60%로 가장 많이 나타났으며 Pasteurella multocida가 63.2%로 높게 분리되었다. 경미한 임상증상을 보인 소에서는 염증세포에 따른 세포상이 고루 나타났으며 Pasteurella multocida가 40% 분리되었다. 세포학적 관찰에서는 정상인 경우는 섬모원주상피세포가 다수 관찰되었고 점액성 염증인 경우는 소수의 호중구 및 상피세포가 관찰되었으며 점액화농성 염증인 경우는 다수의 밀집된 호중구, 상피세포 및 점조한 삼출물이 동시에 관찰되었다. 복합세포성 염증에서는 대식구, 호중구, 임파구 및 상피 세포가 혼재하였다. 이상의 결과로부터 transtracheal aspiration technique은 소의 하부호흡기계 질병을 진단하는데 실제 임상에서 응용할 수 있는 쉽고 안전하며 유익한 방법으로 사료된다.

• Applied Biological Chemistry
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• v.45 no.2
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• pp.114-118
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• 2002

Phenalamides $A_1{\sim}A_3$ were reisolated as cytotoxic substances from culture broth of Myxococcus stipitatus JW111. The producing strain was isolated from the marine sediment collected off the shore of Geomun Island, Korea. The active principles were extracted from cell mass with acetone and successively purified by silica gel column chromatography, Sephadex LH-20 column chromatography, and finally recycling prep. HPLC. These compounds demonstrated significant cytotoxicity against certain human cancer cells, having $IC_50$ values ranging from 0.23 to 0.50 ${\mu}g/ml$. Moreover, they also inhibited the growth of adriamycin-resistant HCT/ADM human cancer cell line as well as its parent sensitive cell line.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.331-338
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• 2014

Myxococcus stipitatus KYC4013 extract exhibited the most potent antifungal activity among the extracts of 207 Myxococcus strains isolated in Korea. High-resolution LC-MS analysis revealed that M. stipitatus KYC4013 produces five antifungal substances and three other secondary metabolites that were predicted to be melithiazol and phenalamide derivatives, respectively. The putative melithiazol derivatives were best produced in CYS medium and the putative phenalamide derivatives were best produced in VY3 medium.

• Korean Journal of Microbiology
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• v.37 no.4
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• pp.239-244
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• 2001

We isolated a Myxobacteria strain from a soil sample obtained from Mt. Daedoon located in Choongnam, Korea. This strain, ARJ, secreted slime while swarmed on the surface of CT medium. It produced greenish yellow pigment in liquid or solid media, and the swarming edge showed green florescence under U. V. at 366 nm. It formed fruiting bodies when nutrient was exhausted, which is one of the most imkportant characteristics of Myxobacteria. The fruiting bodies did not have a stalk and consisted of naked myxospores when examined under the scanning electron microscope. These traits lead us to believe that this strain is very close to Myxococcus virescens. It showed antimicrobial activity, especially against Gram positive bacteria. Culture filtrate showed the activity but this was not due to protein. The culture filtrate also had proteolytic activity in which at least two enzymes are involved.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.458-465
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• 2021

Tubulysins are a group of bioactive secondary metabolites from myxobacteria exhibiting strong anticancer activity against various cancer cell lines. In this study, we describe the identification of putative tubulysin biosynthetic gene clusters (tubA~tubF) in the genome sequences of two tubulysin-producing myxobacterial strains, Archangium gephyra MEHO_002 and MEHO_004. The inactivation of the putative tubulysin biosynthetic genes resulted in a tubulysin-production defect. The DNA sequences of the A. gephyra MEHO_002 and MEHO_004 tubulysin biosynthetic genes were 97% identical, and the amino acid sequences of the encoded proteins shared a similarity of 97-100%. The nucleotide sequences of the tubulysin biosynthetic gene clusters in MEHO_002 and MEHO_004 were 86% identical to that in Cystobacter sp. SBCb004 known as a tubulysin-producing myxobacterium, and the organization of the clusters was identical except for the lack of a tubZ gene in the clusters in MEHO_002 and MEHO_004. The amino acid sequences of the proteins encoded by each gene were 88-97% similar to those encoded by SBCb004, and the domain compositions of the proteins were also identical.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.48-53
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• 2009

591 strains of myxobacteria that grew on cellulose as a sole carbon source were isolated from soils collected from various locations in Korea. Morphological characteristics such as the shape of cells, colonies and fruiting bodies and 16S rRNA sequences of the isolates suggested that all the isolates are Sorangium cellulosum. An antifungal assay has indicated that at least 20 strains among the 114 isolates tested produce antifungal substances inhibiting growth of Candida albicans.