• Molecules and Cells
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• v.19 no.2
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• pp.256-261
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• 2005

In silico analysis of genome of the cyanobacterium Synechocystis sp. PCC 6803 identified two genes, slr0329 and sll0593, that might participate in glucose (Glc) phosphorylation (www.kazusa.or.jp/cyano). In order to determine the functions of these two genes, we generated deletion mutants, and analyzed their phenotypes and enzymatic activities. In the presence of 10 mM Glc, wild-type (WT) and slr0329 defective strain (M1) grew fast with increased respiratory activity and NADPH production, whereas the sll0593 deletion mutant (M2) failed to show any of the Glc responses. WT and M1 were not significantly different in their glucokinase activity, but M2 had 90% less activity. Therefore, we propose that Sll0593 plays a major role in the phosphorylation of glucose in Synechocystis cells.

• BMB Reports
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• v.39 no.4
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• pp.394-399
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• 2006

The transport of putrescine into a moderately salt tolerant cyanobacterium Synechocystis sp. PCC 6803 was characterized by measuring the uptake of radioactively-labeled putrescine. Putrescine transport showed saturation kinetics with an apparent $K_m$ of $92{\pm}10\;{\mu}M$ and $V_{max}$ of $0.33{\pm}0.05\;nmol/min/mg$ protein. The transport of putrescine was pH-dependent with highest activity at pH 7.0. Strong inhibition of putrescine transport was caused by spermine and spermidine whereas only slight inhibition was observed by the addition of various amino acids. These results suggest that the transport system in Synechocystis sp. PCC 6803 is highly specific for polyamines. Putrescine transport is energy-dependent as evidenced by the inhibition by various metabolic inhibitors and ionophores. Slow growth was observed in cells grown under salt stress. Addition of low concentration of putrescine could restore growth almost to the level observed in the absence of salt stress. Upshift of the external osmolality generated by either NaCl or sorbitol caused an increased putrescine transport with an optimum 2-fold increase at 20 mosmol/kg. The stimulation of putrescine transport mediated by osmotic upshift was abolished in chloramphenicol-treated cells, suggesting possible involvement of an inducible transport system.

• Asian Journal of Turfgrass Science
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• v.11 no.1
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• pp.45-58
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• 1997

Pigments and thylakoid membrane proteins were investigated in wild type and PS I- mutants from Synechocystis sp. PCC6803 Comparing morphological features, B2 was less fluorescent than the other strains. The contents of chlorophyll a were propotional to the FNR activity in thylakoid membrane. The FNR activity of mutants was lower than that of wild type. In the result of pigments analysis, mutants had smaller cholophyll a than that of wild type. The major carotenoid was found to he $\beta$-caroene, but aeaxanthin was barely detected in thylakoid membrane of mutants. The polypeptide, 14.8kD was detected by electrophoresis in mutants. It was considered to be the modification of 15.4kD in wild type. Membrane polypeptides of 17.6 and 19.7kD were not detected in mutants. In the result of western blotting, subunit I was detected in all strains, but subunit II was barely detected in mutants. Subunit II was not detected in B2 at all. In view of the results so far achieved, the changes of contents of chlorophyll and zeaxanthin were affected by the defficiency or modification of functional domain in subunit I. Also the modification in subunit I affected the subunit II- binding site in PS I. As the result, efficiency of photosynthesis was decreased. Key words: Synechoystis sp. PCC6803, PS I - mutant, Photosynthetic efficiency, Pigment,Thylakoid membrane proteins, Subunit I, II.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.6
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• pp.529-536
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• 2008

Cyanobacteria Synechocystis PCC 6803 or the extracted thylakoid membrane from this strain was appled to photosynthetic bio-electrochemical fuel cell(PBEFC) for the production of hydrogen under the illumination of 48Klux using halogen lamp. PBEFC was composed of anode, cathode and membrane between them. Electrode material was carbon paper while electron mediator and receptor were added phenazine methosulfate(PMS) and potassium ferricyanide respectively. When water and 50 mM tricine buffer and $300{\mu}M$ PMS were added to the anode under the light condition, PBEFC produced the current density $4.4{\times}10^{-5}\;mA/cm^2$, $1.4{\times}10^{-4}\;mA/cm^2$ and $2.4{\times}10^{-4}\;mA/cm^2$, respectively. And the addition of the thylakoid membrane to the system increased current density to $1.3{\times}10^{-3}\;mA/cm^2$. Two times increase of the thylakoid membrane into the anode doubled the current density to $2.6{\times}10^{-3}\;mA/cm^2$. But the current density was not increased proportionally to the amount of thylakoid membrane increased. The system was unstable to measure the electricity output due to the foam production in the anode. Addition of triton X-100 and tween 80 stabilized the system to measure the electricity output but the current density was not increased higher than $8.4{\times}10^{-4}\;mA/cm^2$ and $2.3{\times}10^{-3}\;mA/cm^2$. When the thylakoid membrane was substituted to Synechocystis PCC 6803 cells of four-day culture which has chlorophyll contents $20.5{\mu}g/m{\ell}$, maximum current density was $1.3{\times}10^{-3}\;mA/cm^2$ with $1\;k{\Omega}$ resistance.

• KSBB Journal
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• v.13 no.1
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• pp.101-107
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• 1998

Carbon dioxide is estimated to be responsible for 60% of the global warming effect, and this percentage is tending upward. Studies on removal and fixation of $CO_2$ in the flue gas are recognized as one of the important roles of the future biotechnology. Photobiological systems have considerably higher photosynthetic efficiency than conventional biomass system. The experiment for the photosynthetic fixation of $CO_2$ and the biomass production was performed with various initial cell concentration in a tubular photobioreactor and a bubble column $CO_2$ contactor with a gas sparger of $CO_2$ -enriched air(0.03~20%). Synechocystis PCC 6803 could grow at 10~20% $CO_2$ content under pH control. The highest specific growth rate, 0.0258 $h^{-1}$ , was obtained at 5% $CO_2$-air mixture. The maximum cell production rate, 0.2784 g/L.day, was obtained when the initial cell concentration was 0.45 g/L at 5% $CO_2$ -air mixture. The maximum cell concentration was 2.03 g/L in the tubular photobioreactor when the light intensity was $45.5{\mu}$ $E/m^2$ . s. This system showed 0.482 g $CO_2$ /L . day of the $CO_2$ fixation.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.66-73
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• 1996

For the effective control of mosquito larvae, Anopheles sinensis, the expression vector pCYASK5-1 containing cryIVD gene of Bacillus thuringiensis subsp. morrisoni PG-14 was constructed and transformed into the cyanobacterium Synechocystis PCC6803. The transformants were selected on BG-11 medium containing kanamycin. The expression of cryIVD gene in transformant was confirmed by SDS-PAGE and Western blot analysis. The mortality of A. sinensis larvae was scored for 3 days. Furthermore, growth and distribution rate of transformant were examined. The results showed that Synechocystis PCC6803 transformed with cryIVD gene of B. thuringiensis subsp. morrisoni PG-14 was highly toxic to A. sinensis larvae, demonstrating that it will be a potential agent for mosquito control.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.35-41
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• 2004

Bacillus thuringiensis produces crystal proteins toxic to medically and agriculturally important pests during sporulation. To improve the activity of insecticidal crystal protein in applying to mosquito larval control, an expression vector, pSyn4D harboring the mosquitocidal cry11Aa gene under control of psbA promoter of Amaranthus hybridus was constructed. This expression vector was transformed into Synechocystis PCC6803 and a transformant, Tr2C was selected with kanamycin. The mosquitocidal cry11Aa gene was stably integrated Into genomic DNA of Tr2C in PCR detection using cry11Aa-specific primers. The transformant expressed 72-kDa Cry11Aa protein and median lethal time (LT$\sub$50/) was approximately 2.1 days for Culex tritaeniorhynchus larvae and 0.7 day for Anopheles sinensis larvae, respectively. These results suggest this transformant can be used for mosquito larval control as a biological control agent.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.103-110
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• 2003

The regulation of pyrimidine nucleotide synthesis has been proved to be controlled by a regulatory protein PyrR-mediated attenuation in the Gram-positive bacteria. After several bacterial genome sequencing projects, we have discovered the PyrR orthologues in the databases for Haemophilus influenzae and Synechocystis and sp. PCC6803 genome sequences. To investigate whether these PyrR orthologue proteins regulate pyrimidine nucleotide synthesis as well as the cases of Bacillus, the PyrR regions of each strains were amplified by PCR and cloned with pUC19 or T-vector in Escherichia coli and with a shuttle vector pHPS9 for E. coli and B. subtilis. For the regulation test of the PyrR orthologues, the aspartate-transcarbamylase (ATCase) assay was carried out. From the results of the ATCase assay, it was confirmed that Synechocystis sp. PCC6803 could not restore by pyrimidines to a B. subtilis, PyrR but H. influenzae PyrR could. For Purification of PyrR orthologue proteins, PyrR orthologue genes were cloned into the expression vector (pET14b). Over-expressed product of PyrR orthologue genes was purified and analyzed by the SDS-PACE. The purified PyrR orthologue proteins from H. influenzae and Synechocystis sp. PCC6803 turned out to be molecular mass of 18 kDa and 21 kDa, respectively. The result of uracil phosphoribosyl transferase (UPRTase) assay with purified PyrR orthologue proteins showed that H. influenzae PyrR protein only has UPRTase activity. In addition, we could predict several regulatory mechanisms that PyrR orthologue proteins regulate pyrimidine de novo synthesis in bacteria, through phylogenetic analysis for PyrR orthologue protein sequences.

• The Microorganisms and Industry
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• v.17 no.3
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• pp.2-14
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• 1991

• Journal of Microbiology and Biotechnology
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• v.24 no.8
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• pp.1015-1025
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• 2014

Microorganisms that live in the rhizosphere play a pivotal role in the functioning and maintenance of soil ecosystems. The study of rhizospheric cyanobacteria has been hampered by the difficulty to culture and maintain them in the laboratory. The present work investigated the production of the plant hormone indole-3-acetic acid (IAA) and the potential of biofilm formation on the rhizoplane of pea plants by two cyanobacterial strains, isolated from rice rhizosphere. The unicellular cyanobacteria Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 that were isolated from a rice rhizosphere, were investigated. Production of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 was measured under experimental conditions (pH and light). The bioactivity of the cyanobacterial auxin was demonstrated through the alteration of the rooting pattern of Pisum sativum seedlings. The increase in the concentration of L-tryptophan and the time that this amino acid was present in the medium resulted in a significant enhancement of the synthesis of IAA (r > 0.900 at p = 0.01). There was also a significant correlation between the concentration of IAA in the supernatant of the cyanobacteria cultures and the root length and number of the pea seedlings. Observations made by confocal laser scanning microscopy revealed the presence of cyanobacteria on the surface of the roots and also provided evidence for the penetration of the cyanobacteria in the endorhizosphere. We show that the synthesis of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 occurs under different environmental conditions and that the auxin is important for the development of the seedling roots and for establishing an intimate symbiosis between cyanobacteria and host plants.