• Title/Summary/Keyword: Synechocystis PCC 6803

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Cyanobacterial bioreporters for detection of heavy metals, herbicide, and antibiotics (중금속, 제초제 및 항생제 검출용 남세균 유래 바이오 리포터)

  • Kim, Soo-Youn;Jeong, Won-Joong;Suh, Kye-Hong;Liu, Jang-Ryol;Park, Youn-Il
    • Journal of Plant Biotechnology
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    • v.35 no.2
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    • pp.141-145
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    • 2008
  • In this study, glucose-inducible intergenic sequences were used to generate bioreporters of the cyanobacterium Synechocystis sp. PCC 6803 that could monitor environmental pollutants. Luciferase genes LuxAB from the marine bacterium Vibrio fischeri under the control of glucose-inducible intergenic seqeucens of eight genes (atpI, ndbA, ctaD1, tkt, pgi, pdh, ppc, and cydA) were successfully expressed in the cyano-bacterial transformants, showing 5-25 fold increases in biolumeniscence upon exposure to glucose. In addition, glucose-inducible cyanobacterial bioreporters were very sensitive to various chemicals such as heavy metals ($Hg^{2+}$, $Cu^{2+}$, $Zn^{2+}$), electron transport inhibitors (DCMU, DBMIB, $CN^-$), and antibiotics (chloramphenicol and rifampicin). These glucose-inducible cyanobacterial bioreporters would be useful to develop biosensors for rapid screening of environmental samples.

A NOVEL PHOTOHETEROTROPHIC MUTANT FOR psaB GENE OF Synechocystis sp. PCC 6803 GENERATED FROM TARGETED MUTAGENESIS

  • Kim, Soohyun;Kim, Seung-Il;Choi, Jong-Soon;Chung, Young-Ho;Chun, Soon-Bai;Park, Young-Mok
    • Journal of Photoscience
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    • v.3 no.1
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    • pp.23-28
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    • 1996
  • To investigate the structure and function of photosystem I, cartridge mutagenesis technique was used to inactivate the psaB gene of photosystem I. From the screen, many strains which have potential defects in photosystem I were generated. Biochemical analysis revealed that B2, one of the mutant, had a reduced amount of chlorophyll. Electron transfer activitx from photosystem II to photosystem I as oxygen uptake was the rate of 64 % of wild type. Also B2 showed a decreased photosystem I activity when measured by 77 K fluorescence emission spectrum. Particularly, immunodetection analysis showed that the B2 had reduced amount of PsaA/PsaB, but a normal range of PsaC and PsaD. Here we present a photoheterotrophic mutant for psaB gene as a unique model strain for future study of structural/functional relationship and biogenesis of photosystem I.

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Characterization of the Nickel Resistance Gene from Legionella pneumophila: Attenuation of Nickel Resistance by ppk (polyphosphate kinase) Disruption in Escherichia coli

  • Hahm, Dae-Hyun;Yeon, Mi-Jung;Ko, Whae-Min;Lee, Eun-Jooh;Lee, Hye-Jung;Shim, In-Sop;Kim, Hong-Yeoul
    • Journal of Microbiology and Biotechnology
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    • v.12 no.1
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    • pp.114-120
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    • 2002
  • A 1,989-bp genomic region encoding nickel resistance genes was isolated from Legionella pneumophila, a pathogen for legionellosis. From a sequencing and computer analysis, the region was found to harbor two structural genes, a nreB-like protein gene (1,149 bp) and a nreA-like protein gene (270 bp), in a row. Both genes exhibited a significant degree of similarity to the corresponding genes from Synechocystis sp. PCC6803 ($54\%$ amino acid sequence identity) and Achromobacter xylosoxidans 31A ($76\%$). The gene was successfully expressed in E. coli MG1655 and conferred a nickel resistance of up to 5 mM in an LB medium and 3 mM in a TMS medium including gluconate as the sole carbon source. E. coli harboring the nickel resistance gene also exhibited a substantial resistance to cobalt, yet no resistance to cadmium or zinc. Since the extracellular concentration of nickel remained constant during the whole period of cultivation, it was confirmed that the nickel resistance was provided by an efflux system like the $Ni^2+$permease (nrsD) of Synechocystis sp. strain PCC6803. Since polyphosphate (poly-P) is known as a global regulator for gene expression as well as a potential virulence factor in E. coli, the nickel resistance of a ppk mutant of E. coli MG 1655 harboring the nickel resistance gene from L. pneumophila was compared with that of its parental strain. The nickel resistance was significantly attenuated by ppk inactivation, which was more pronounced in an LB medium than in a TMS medium.