• 미생물학회지
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• 제32권1호
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• pp.65-69
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• 1994

Synechococcus sp.의 cyanophage는 early, late viral function 모두 빛을 필요로 하는 것으로 나타났으며 증식 초기 2시간 동안 암처리한 경우 200%의 burst size를 나타내었다. Dark 상태에서의 Synechococcus sp.의 cyanophage증식은 대조군에 비해 11%의 burst size를 나타내었다. 광합성 억제제인 DCMU를 $10^{-6}$M로 처리했을 때 virus yield가 2%로 감소했으며 $10^{-4}$M의 CCCP는 cyanophage의 증식을 거의 중지시켰다. 또한 이러한 숙주세포의 광합성 의존도는 LPP-1, N-1과 AS-1보다는 크나 SM-1보다는 작은 것으로 나타났다.

• 상하수도학회지
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• 제34권6호
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• pp.437-443
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• 2020

Biological phosphorus removal is accomplished by exposing PAO(phosphorus accumulating organisms) to anaerobic-aerobic conversion conditions. In the anaerobic condition, PAO synthesize PHB(polyhydroxybutyrate) and simultaneously hydrolysis of poly-p resulting phosphorus(Pi) release. In aerobic condition, PAO uptake phosphorus(Pi) more than they have released. In this study, cyanobacteria Synechococcus sp., which is known to be able to synthesize PHB like PAO, was exposed to anaerobic-aerobic conversion. If Synechococcus sp. can remove excess phosphorus by the same mechanism as PAO, synergistic effects can occur through photosynthesis. Moreover, Synechococcus sp. is known to be capable of synthesizing PHB using inorganic carbon as well as organic carbon, so even if the available capacity of organic carbon decreases, it was expected to show stable phosphorus removal efficiency. In 6 hours of anaerobic condition, phosphorus release occurred in both inorganic and organic carbon conditions but SPRR(specific phosphorus release rate) of both conditions was 10 mg-P/g-MLSS/day, which was significantly lower than that of PAO. When converting to aerobic conditions, SPUR(specific phosphorus uptake rate) was about 9 mg-P/g-MLSS/day in both conditions, showing a higher uptake rate than the control condition showing SPUR of 6.4 mg-P/g-MLSS/day. But there was no difference in terms of the total amount of removal. According to this study, at least, it seems to be inappropriate to apply Synechococcus sp. to luxury uptake process for phosphorus removal.

• ALGAE
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• 제30권4호
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• pp.281-290
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• 2015

We explored phagotrophy of the phototrophic ciliate Mesodinium rubrum on the cyanobacterium Synechococcus. The ingestion and clearance rates of M. rubrum on Synechococcus as a function of prey concentration were measured. In addition, we calculated grazing coefficients by combining the field data on abundance of M. rubrum and co-occurring Synechococcus spp. with laboratory data on ingestion rates. The ingestion rate of M. rubrum on Synechococcus sp. linearly increased with increasing prey concentrations up to approximately 1.9 × 10⁶ cells mL^-1, to exhibit sigmoidal saturation at higher concentrations. The maximum ingestion and clearance rates of M. rubrum on Synechococcus were 2.1 cells predator^-1 h^-1 and 4.2 nL predator^-1 h^-1, respectively. The calculated grazing coefficients attributable to M. rubrum on cooccurring Synechococcus spp. reached 0.04 day^-1. M. rubrum could thus sometimes be an effective protistan grazer of Synechococcus in marine planktonic food webs. M. rubrum might also be able to form recurrent and massive blooms in diverse marine environments supported by the unique and complex mixotrophic arrays including phagotrphy on hetrotrophic bacteria and Synechococcus as well as digestion, kleptoplastidy and karyoklepty after the ingestion of cryptophyte prey.

• 미생물학회지
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• 제30권6호
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• pp.524-527
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• 1992

경기도 의왕시에 위치한 백운 저수지에서 분리된 cyanobacteria 인 Synechococcus sp. 로부터 한 종의 cyanophage 를 분리하여 ultrafiltration, differential centrifugation 과 sucrose density gradient centrifugation 을 이용하여 정제하였다. 분리된 cynophage 는 transmission electron microscope (TEM) 를 이용하여 100,000 배로 관찰한 결과 직경이 89 nm인 isometric head 와 tail 의 전체 길이가 111 nm 의 contractile tail 을 가진 phage 로서 Myoviridae 에 속함을 알 수 있었다. 생화학적 특징으로는 20~$40^{\circ}C$ 와 pH 5-10에서 50% 이상의 안정성을 유지하며 $30^{\circ}C$ 와 pH 9 에서 최고의 infectivity 를 나타내었다.

• Journal of Microbiology
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• 제43권2호
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• pp.191-195
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• 2005

In this study, we attempted to characterize the Synechococcus sp. pee 7942 mutant resultant from a disruption in the gene encoding UDP-glucose: tetrahydrobiopterin a-glucosyltransferase (BGluT). 2D­PAGE followed by MALDI-TOF mass spectrometry revealed that phycocyanin rod linker protein 33K was one of the proteins expressed at lower level in the BGluT mutant. BGluT mutant cells were also determined to be more sensitive to high light stress. This is because photosynthetic O$_2$ exchange rates were significantly decreased, due to the reduced number of functional PSIs relative to the wild type cells. These results suggested that, in Synechococcus sp. pee 7942, BH4-glucoside might be involved in photosynthetic photoprotection.

• Journal of Ecology and Environment
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• 제29권5호
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• pp.433-438
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• 2006

To elucidate the mechanisms by which algal food quality affect Daphnia growths, we measured carbon incorporation rates and respiration rates of Daphnia magna with Cryptomonad Rhodomonas minuta, green algae Scenedesmus acutus and cyanobacteria Synechococcus sp. with varying physiological states as food. Carbon assimilation rates were high with R. minuta and S. acutus and low with Synechococcus sp. showing a similar pattern to the growth rate pattern. There was no clear difference among respiration rates of three algal species. Carbon assimilation rates and respiration rates of D. magna appeared to be independent on Molar C:P ratios in algal foods. Carbon growth efficiencies (incorporated carbon per assimilated carbon amount) were lower when D. magna fed with Synechococcus sp. than fed with R. minuta or S. acutus. Analysis of variance results show that carbon assimilation rates which were sum of incorporation and respiration rates and carbon growth efficiencies were only dependant on species affiliation. Overall, our results showed that algal species with varying ${\omega}3$ polyunsaturated fatty acid content led different carbon incorporation rates and overall carbon assimilation rates of D. magna.

• 한국수소및신에너지학회논문집
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• 제21권2호
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• pp.104-110
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• 2010

Photobiological hydrogen production by nitrogen-fixing unicellular cyanobacteria has long been considered to be an environmentally sound and very promising method for the future supply of renewable clean energy. We tried to find out the optimum cell concentration for $H_2$ production in each of the two new Korean nitrogen-fixing unicellular cyanobacterial strains to compare with Synechococcus sp. strain Miami BG043511. The two Korean strains, Cyanothece sp. KNU CB MAL-031 and KNU CB MAL-058, were isolated from Korean west coasts. Cell concentrations up to 17 billion cells $ml^{-1}$ were applied to the tests. High cell concentration over 15 billion cells $ml^{-1}$ resulted in drastically reduced $H_2$ production in all the three strains. The two domestic strains, however, produced 2-3 time more hydrogen than Synechococcus sp. Miami BG043511 at cell concentrations of 5-10 billion cells $ml^{-1}$. At lower cell concentrations than 2 billion cells $ml^{-1}$, MAL-031 exhibited highest $H_2$ production followed by Miami BG043511, with far less production in MAL-058. Present result suggests that Cyanothece sp. MAL-CB031 might be one of the ideal nitrogen-fixing unicellular cyanobacterial strains for the photobiological hydrogen production.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2001년도 추계학술대회
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• pp.105-105
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• 2001

• 미생물학회지
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• 제33권4호
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• pp.242-246
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• 1997

Synechococcus sp. cyanophage의 SDS-PAGE 수행 결과 구조단백질은 두 개의 major protein(97 kDa, 52 kDa)과 최소 일곱 개의 minor protein(70 kDa, 65 kDa, 60 kDa, 40 kDa, 35 kDa, 28 kDa, 6 kDa)으로 구성되어 있는 것으로 나타났다. Subunit들은 서로 disulfide bond로 연결되어 있지는 않지만 비공유적 결합으로 multimer를 형성하여 phage particle을 구성하고 있는 것으로 보인다. 또한 heat-killed Micrococcus luteus cell을 기질로 이용한 renaturing SDS-PAGE 방법으로 phage particle내의 세포벽 분해능을 살표본 결과 52 kDa 부근에서 세포벽 분해활성이 발견되었다. 이러한 세포벽 분해활성은 최적 pH가 9~10 사이이며 EDTA에 대한 낮은 저해를 나타내었다.

• Journal of the korean society of oceanography
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• 제31권1호
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• pp.18-22
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• 1996

The effect of exogenous oxygen on hydrogen photoproduction was examined in the synchronously grown cells of marine Synechococcus sp. Miami BG 043511 under conditions of high cell density (0.6-0.8 mg chl-${\alpha}$ $ml^{-1}$) and high light intensity (1000 ${\mu}$E $m^{-2}$ $s^{-1}$). Hydrogen evolution after 20-h incubation did not decline under the initial oxygen concentrations up to 20%, but declined by half under 34% oxygen. 50% and 100% oxygen gas phase did not completely inhibit the hydrogen photoproduction during 40-h incubations. After 2-day pretreatment under 100% exogenous oxygen the hydrogen photoproduction capabilities were not irreversibly inhibited, which was demonstrated in the subsequent 9-day incubation under initial 0, 50 and even under 100% oxygen gas phase. This strain could be useful for developing a hydrogen photoproduction system under atmospheric oxygen concentration.