• Animal cells and systems
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• 제6권4호
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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 and Biotechnology
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• 제10권1호
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• pp.115-118
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• 2000

Recombinant plasmids harboring a heterologous gene coding for the enhanced green fluorescent protein (EGFP) were transfected and expressed in Drosophila melanogaster S2 cells. A stable transformation of polyclonal cell populations expressing EGFP were isolated after 4 weeks of selection with hygromycin B. The recombinant EFGP expressed in transformed S2 cells consisted of a molecular weight of 27 kDa. EGFP expression was also confirmed by fluorometric measurement. The maximum EGFP concentration was about 9.3 mg/I. The present findings demonstrate not only the successful stable expression of EGFP in Drosophuila was about 9.3 mgI. The present findings demonstrate not only the successful stable expression of EGFP in Drosophila S2 cells, but also the use of EGFP as a reporter to analyze gene expression, with its potential of a Drosophila cell expression system for recombinant protein production being an alternative to a baculovirus-insect cell expression system.

• International Journal of Industrial Entomology and Biomaterials
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• 제29권2호
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• pp.185-192
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• 2014

Recombinant proteins can be generated quickly and easily in large amounts and at low-cost in silkworm larvae by using Bombyx mori nuclear polyhedrosis virus (BmNPV). We searched for high-permissive silkworm strains that have high production levels of heterologous proteins and are thus suitable for use as biofactories. In this study, we performed the analysis using a BmNPV vector expressing luciferase as a marker, and we confirmed protein expression by evaluating luciferase activity, determined by western blotting and luciferase ELISA, and confirmed transcription expression by semi- and quantitative real time PCR. For the selection of host silkworm strains, we first chose 52 domestic BmNPV sensitive strains and then identified 10 high-permissive and 5 low-permissive strains. In addition, to determine which hybrid of the high-permissive strains would show heterosis, nine strains derived through three-way crossing were tested for luciferase activity by western blotting, and luciferase ELISA. We found a correlation between luciferase activity and luciferase protein expression, but not transcription. There was no noticeable difference in protein expression levels between Jam313 as the high-permissive control strain and the three-way hybrid strains; however, the three-way cross strains showed lower luciferase activity compared with Jam313. In this study, luciferase protein production in the larvae of 52 domestic silkworm strains was elucidated using BmNPV.

• 한국해양바이오학회지
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• 제16권1호
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• pp.45-54
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• 2024

Microalgae have great potential in the biomedical and pharmaceutical industries as a new type of bioreactor that can produce proteins for specific purposes, including recombinant proteins, pharmaceuticals, and industrial enzymes. Despite the production advantages and importance of microalgae-based expression systems, studies on secretion efficiency are limited. In this study, for stable expression and efficient secretion of the heterologous protein (human SCF and human INFγ) in Chlorella vulgaris, we constructed SP:hSCF:His and SP:hINFγ:His plant binary vectors using the signal peptide (SP) of Chlamydomonas reinhardtii, and we obtained stable transformants through the effective agrobacterium-mediated transformation of these vectors. Transformants with accurately inserted hSCF and hINFγ demonstrated stably increased mRNA and protein expression using RT-PCR and western blotting under the same culture conditions. Following the analysis of the proteins secreted into the culture medium using ELISA, it was confirmed that hINFγ was effectively produced in the transformed C. vulgaris culture medium. The overall findings indicate that the combination of heterologous protein and SP may be crucial for ensuring the expression and secretion of recombinant proteins in Chlorella culture systems.

• Molecules and Cells
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• 제27권5호
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• pp.601-608
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• 2009

The 2-deoxystreptamine and paromamine are two key intermediates in kanamycin biosynthesis. In the present study, pSK-2 and pSK-7 recombinant plasmids were constructed with two combinations of genes: kanABK, and kanABKF and kacA respectively from kanamycin producer Streptomyces kanamyceticus ATCC12853. These plasmids were heterologously expressed into Streptomyces lividans TK24 independently and generated two recombinant strains named S. lividans SK-2/SL and S. lividans SK-7/SL, respectively. ESI/ MS and ESI-LC/MS analysis of the metabolite from S. lividans SK-2/SL showed that the compound had a molecular mass of 163 $[M+H]^+$, which corresponds to that of 2-deoxystreptamine. ESI/MS and MS/MS analysis of metabolites from S. lividans SK-7/SL demonstrated the production of paromamine with a molecular mass of $324[M+H]^+$. In this study, we report the production of paromamine in a heterologous host for the first time. This study will evoke to explore complete biosynthetic pathways of kanamycin and related aminoglycoside antibiotics.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.479-479
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• 2003

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.217.3-217
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• 2005

• Journal of Microbiology
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• 제37권2호
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• pp.102-110
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• 1999

Genetic determinant for the secondary metabolism was studied in heterologous expression in Streptomyces lividans TK-24 using Streptomyces griseus ATCC 10137 as a donor strain. Chromosomal DNA of S. griseus was ligated into the high-copy number Streptomyces shuttle plasmid, pWHM3, and introduced into S. lividans TK-24. A plasmid clone with 4.3-kb BamHI DNA of S. griseus (pMJJ201) was isolated by detecting for stimulatory effect on actinorhodin production by visual inspection. The 4.3-kb BamHI DNA was cloned into pWHM3 under the control of the strong constitutive ermEp promoter in both directions (pMJJ202); ermEp promoter-mediated transcription for coding sequence reading right to left: pMJJ203; ermEp promoter-mediated transcription for coding sequence reading left to right) and reintroduced into S. lividans TK-24. The production of actinorhodin was markedly stimulated due to introduction of pMJJ202 on regeneration agar. The introduction of pMJJ202 also stimulated production of actinorhodin and undecylproidigiosin in submerged culture employing the actinorhodin production medium. Introduction of pMJJ203 resulted in a marked decrease of production of the two pigments. Nucleotide sequence analysis of the 4.3-kb region revealed three coding sequences: two coding sequences reading left to right, ORF1 and ORF2, one coding sequence reading right to left, ORF3. Therefore, it was suggested that the ORF3 product was responsible for the stimulation of antibiotic production. The C-terminal region of ORF3 product showed a local alignment with Myb-related transcriptional factors, which implicated that the ORF3 product might be a novel DNA-binding protein related to the regulation of secondary metabolism in Streptomyces.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.66-71
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• 2016

PikD is a widely known pathway-specific regulator for controlling pikromycin production in Streptomyces venezuelae ATCC 15439, which is a representative of the large ATP-binding regulator of the LuxR family (LAL) in Streptomyces sp. RapH and FkbN also belong to the LAL family of transcriptional regulators, which show greatest homology with the ATP-binding motif and helix-turn-helix DNA-binding motif of PikD. Overexpression of pikD and heterologous expression of rapH and fkbN led to enhanced production of pikromycin by approximately 1.8-, 1.6-, and 1.6-fold in S. venezuelae, respectively. Cross-complementation of rapH and fkbN in the pikD deletion mutant (ΔpikD) restored pikromycin and derived macrolactone production. Overall, these results show that heterologous expression of rapH and fkbN leads to the overproduction of pikromycin and its congeners from the pikromycin biosynthetic pathway in S. venezuelae, and they have the same functionality as the pathwayspecific transcriptional activator for the pikromycin biosynthetic pathway in the ΔpikD strain. These results also show extensive "cross-communication" between pathway-specific regulators of streptomycetes and suggest revision of the current paradigm for pathwayspecific versus global regulation of secondary metabolism in Streptomyces species.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1115-1118
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• 2008

${\alpha}$-Galactosidase gene (aga) from Leuconostoc mesenteroides SY1 was expressed in a heterologous host, Lactobacillus brevis 2.14 using an Escherichia coli-Leuconostoc shuttle vector, pSJE. pSJEaga (pSJE carrying aga) was introduced into Lactobacillus brevis 2.14 by electroporation and transformation efficiency was $1.1{\times}10^3$ per ${\mu}g$ DNA. L. brevis transformants (TFs) showed higher ${\alpha}$-galactosidase (${\alpha}$-Gal) activities than cells containing pSJE. Transcription levels of aga in L. brevis 2.14 grown on different carbon sources (1%, w/v) were examined by slot blot analysis. Aga transcript levels and ${\alpha}$-Gal activities were higher in cells grown on melibiose, raffinose, and galactose than cells on glucose, sucrose, and fructose. Western blot result showed that L. brevis 2.14 harboring pSJEaga produced much more ${\alpha}$-Gal when grown on melibiose than on glucose.