• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.64-64
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• 1994

No Abstract, See Full Text

• Mycobiology
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• v.42 no.1
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• pp.34-40
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• 2014

Usnea longissima has a long history of use as a traditional medicine. Several bioactive compounds, primarily belonging to the polyketide family, have been isolated from U. longissima. However, the genes for the biosynthesis of these compounds are yet to be identified. In the present study, three different types of non-reducing polyketide synthases (UlPKS2, UlPKS4, and UlPKS6) were identified from a cultured lichen-forming fungus of U. longissima. Phylogenetic analysis of product template domains showed that UlPKS2 and UlPKS4 belong to group IV, which includes the non-reducing polyketide synthases with an methyltransferase (MeT) domain that are involved in methylorcinol-based compound synthesis; UlPKS6 was found to belong to group I, which includes the non-reducing polyketide synthases that synthesize single aromatic ring polyketides, such as orsellinic acid. Reverse transcriptase-PCR analysis demonstrated that UlPKS2 and UlPKS4 were upregulated by sucrose; UlPKS6 was downregulated by asparagine, glycine, and alanine.

• Natural Product Sciences
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• v.17 no.1
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• pp.14-18
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• 2011

A chemical investigation of the marine-derived fungi Aspergillus versicolor led to the isolation of a new aromatic polyketide (1), The structure was elucidated by spectroscopic analysis, and its radical-scavenging activity, reducing power, and inhibitory activity to lipid oxidation were investigated. Those activities of compound 1 were compared with standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiarybutylhydroquinone (TBHQ), and ascorbic acid ($V_C$). Compound 1 showed antioxidant activity comparable to that of BHA, and siginificantly higher than that of BHT.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.74-79
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• 1995

Sequence analysis of a DNA region encompassing the site of hybridization to actl, the gene for type II minimal polyketide synthase (PKS) for actinorhodin biosynthesis, from Streptomyces ablus revealed three more complete open reading frames additional to the already found two genes, plausibly encoding ${\beta}-ketoacyl$ synthase/acyl transferase (KS/AT) and chain length determining factor (ClF). The open reading frames (ORFs) were named salA, salD, and salE, from the upstream. In the homology analysis of the deduced amino acid sequences, SalA resembles the Streptomyces glaucescens Tcml, decaketide cyclase, SalD resembles acyl carrier protein in type II PKS, and SalE resembles the Actlll ketoreductase, The whole 4.4 kb of DNA sequence obeys the same conservation pattern as other type II PKSs. Therefore, we suggest that the 4.4 kb DNA from Streptomyces albus encompasses genes encoding enzymes for polyketide biogenesis in the organism and its organization is type II. The exsitence of SaIA, an analogue of the aromatic cyclase, revealed a relatedness of the 4.4 kb DNA with the aromatic PKS.

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1796-1800
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• 2015

Sporopollenin is a poorly characterized mixed aliphatic and aromatic polymer with ester and ether linkages. Recent studies have reported that α-pyrone polyketide compounds generated by Arabidopsis thaliana, polyketide synthase A (PKSA) and tetraketide α-pyrone reductase 1 (TKPR1), are previously unknown sporopollenin precursors. Here, the yeast Saccharomyces cerevisiae was introduced to test potential sporopollenin biosynthetic pathways in vivo. A PKSA/TKPR1 dual expressor was generated and various chain-length alkyl α-pyrones were identified by GC-MS. The growth rate of the strain containing PKSA/TKPR1 appeared normal. These results indicate that PKSA/TKPR1-expressing yeast would be a starting platform to investigate in vivo sporopollenin metabolism.

• Animal cells and systems
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• v.6 no.4
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• pp.305-309
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• 2002

Actinorhodin antibiotics produced by Streptomyces lividans TK24 are blue pigments with a weak antibiotic activity, derived from one acetyl-CoA and 15 malonyl-CoA units via a typical ployketide pathway. In an attempt to clone polyketide biosynthetic genes of S. lividans TK24, hybridizing fragments in the genomic DNA of S. lividans TK24 were detected by use of acn and act III polyketide synthase gene probes. Since typical aromatic polyketide bio-synthetic gene clusters are roughly 22-34 Kb long, we constructed in E. coli XL-Blue MR using the Streptomyces-E. coli bifunctional shuttle cosmid vector (pojn46). Then, about 5,000 individual E. coii colonies were thor-oughly screened with acrl-ORFI and actIII probes. From these cosmid libra-ries, 12 positive clones were identified. Restriction analysis and southern hybridization showed two polyketide biosynthetic gene clusters in this organism. These cosmid clones can be transformed into Streptomyces parvulus 12434 for expression test that identify product of actinorhodin biosynthetic genes by heterologous expression. Thus, heterologous expres-sion of a derivative compound of a actinorhodin biosynthetic intermediate was obtained in pKE2430. Expression of these compounds by the trans-formants was detected by photodiode array HPLC analysis of crude extracts.

• Journal of Microbiology
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• v.35 no.1
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• pp.40-46
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• 1997

The pWHM220 cosmid with a 24-kb insert cloned from Streptomyces albus ATCC 21838 induces the biosynthesis of a polysther antibiotic similar to salinomycin in Streptomyces invidans. We have analyzed this region by DNA sequencing as well as Southern blot hybridization with type I and type II polyketide synthase (PKS) probes. Surprisingly, we found another set of type II SKS genes only 10-kb from the original PKS genes, salABCDE. The DNA sequence revealed two complete open reading frames (ORFs) named salB2 and salC2, and one partial ORF that does not resemble any known DNA or deduced protein sequence. The salC2 should code for chain length determining factor while the deduced amino acid sequence encoded by salB2 exhibits high similarity to .betha.-ketoacyl synthase from different PKS gene clusters. The highest identity was found for .betha.-keetoacyl synthases from S. argillaceus (MtmP. 59.1% identity), the mithramycin producer and from S. venezuelae ISP5230 (JadA, 52.3% identity), the jadomycin producer. The SalC2 protein clearly resembles its counterparts in order aromatic PKS gene clusters that are believed to influence the length of the polyketide chain. The highest identities observed were to that of S. argillaceus (MtmK, 62.3%) and S. venezuelae ISP 5230 (JadB, 55.1%) proteins, Moreover, the deduced amino acid sequences of the salB2 and salC2 products were 29.0% identical.

• KSBB Journal
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• v.23 no.1
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• pp.44-47
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• 2008

Anthracycline antibiotics doxorubicin (DXR) is clinically important cancer therapeutic agent produced by Streptomyces peucetius. DXR result by further metabolism of rhodomycin D (RHOD) and require a deoxy-sugar component for their biological activity. In this study, production of TDP-L-daunosamine and its attachment to ${\varepsilon}$-rhodomycinone (RHO) to generate RHOD has been achieved by bioconversion in Streptomyces venezuelae that bears eleven genes. S. peucetius seven genes (dnmUTJVZQS) were transformed by plasmid and S. venezuelae two genes desIII, IV and two more S. peucetius drrA, B genes were integrated into chromosomal DNA. To generate the feeding substrate RHO, 6L S. peucetius grown on agar plate was harvested, extracted with organic solvent and then purified using preparative HPLC. Recombinant S. venezuelae grown on agar plate containing RHO was harvested and its n-butanol soluble components were extracted. The glycosylated product of aromatic polyketide RHO using heterologous host S. venezuelae presents the minimal information for TDP-L-daunosamine biosynthesis and its attachment onto aglycone. Moreover, the structure of auxiliary protein, DnrQ, was predicted by fold recognition and homology modeling in this study. This is a general approach to further expand of new glycosides of antitumor anthracycline antibiotics.