• Journal of Plant Biology
• /
• 제34권4호
• /
• pp.267-273
• /
• 1991

Polyamine levels in the male and female cells as well as DNA methyltransferase activity in the female cells during gametogenesis of Chlamydomonas reinhardtii indicated that both spermidine and spermine levels were decreased while DNA methyltransferase activity was markedly increased about 12 hours after the onset of gametogenesis. In vitro, putrescine and spermine at 1 mM inhibited methylation of chloroplasts DNA isolated from vegetative female cells by 35% and 65%, respectively. Spermine was found to be more inhibitory than putrescine at all concentrations tested. The pattern of the inhibition by polyamines appeared different from that caused by cations. The results obtained in this work suggest that the polyamine inhibition of DNA methylation is due to an action of polyamines on the enzyme involved instead of on the DNA itself.

• Journal of Plant Biology
• /
• 제33권4호
• /
• pp.217-223
• /
• 1990

Restriction enzyme inhibiting substance (REIS) extracted from spinach chloroplast and Chlamydomonas seems not to be proteinaceous, because its inhibiting activity was not lost by heat or trypsin treatment. And it seems not to be lipid or polysacchride, because its inhibiting activity was not lost by lipase or $\alpha$-amylase treatment, respectively. In Chlamydomonas, putrescine, spermidine and spermine were present. The amount of putrescine was the smallest and that of spermie was the greatest. But only spermine was contained in REIS and the activity of REIS. It was proportional to the amount of spermine in REIS and it was hindered by Na+ ion. So, the inhibiting activity of REIS seems to be deeply related to spermine contained in REIS. But restriction enzyme inhibiting activity remained to the some extent although salts and spermine were eliminated by dialysis.

• Journal of Microbiology and Biotechnology
• /
• 제23권7호
• /
• pp.923-931
• /
• 2013

Rapamycin, known as an inhibitor of Target of Rapamycin (TOR), is an immunosuppressant drug used to prevent rejection in organ transplantation. Despite the close association of the TOR signaling cascade with various scopes of metabolism, it has not yet been thoroughly investigated at the metabolome level. In our current study, we applied mass spectrometric analysis for profiling primary metabolism in order to capture the responsive dynamics of the Chlamydomonas metabolome to the inhibition of TOR by rapamycin. Accordingly, we identified the impact of the rapamycin treatment at the level of metabolomic phenotypes that were clearly distinguished by multivariate statistical analysis. Pathway analysis pinpointed that inactivation of the TCA cycle was accompanied by the inhibition of cellular growth. Relative to the constant suppression of the TCA cycle, most amino acids were significantly increased in a time-dependent manner by longer exposure to rapamycin treatment, after an initial down-regulation at the early stage of exposure. Finally, we explored the isolation of the responsive metabolic factors into the rapamycin treatment and the culture duration, respectively.

• ALGAE
• /
• 제18권2호
• /
• pp.121-127
• /
• 2003

The pyrenoid ultrastructure and distribution of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and Rubisco activase in the chloroplasts of Chlamydomonas reinhardtii was studied using the immunogold localization technology with electron microscopy. There were several tubular thylakoids invading in the pyrenoid matrix to form several spokewise channels. The connections between pyrenoid matrix and stroma of chloroplast were the partial of channels. The starch sheath surrounding the pyrenoid was separated into several parts by the connections in transection. Some thylakoids were packed together near the connections in one side of the pyrenoid. Those special structures might be used to transport substance between pyrenoid and stroma of chloroplasts. With the antibody raised against the large subunits of Rubsico from C. protothecoides, the result of the gold immunolocalization of Rubisco in Chlamydomonas reinhardtii showed most of the gold particles heavily labeled the pyrenoid matrix, as well as the starch sheath matrix, and very few in the stroma of chloroplasts. The gold particle density was 880.00 $\pm$ 164.32, 190.00 $\pm$ 152.39 and 9.60 $\pm$ 5.37 ${\mu}m^{-2}$ in pyrenoid matrix, starch sheath and stroma region of chloroplast respectively (background: 5.67 $\pm$ 1.53 ${\mu}m^{-2}$). 99.59% of the total Rubiscos was calculated to be concentrated in the pyrenoid matrix and starch sheath by spatial densities. The gold immunolocalization of Rubisco activase also showed that Rubisco activase was mainly concentrated in the periphery of the pyrenoid and the starch sheath (the density was as high as 229.69 $\pm$ 96.96 ${\mu}m^{-2}$). There were very few gold particles located in the stroma of chloroplasts. These results indicated that pyrenoid surface and starch sheath was the site for Rubisco activation and $CO_2$ fixation, which supported the suggestion that pyrenoids perform photosynthesis function.

• Ocean and Polar Research
• /
• 제28권2호
• /
• pp.107-117
• /
• 2006

Freshwater algal studies in North polar environments are relatively few. This study presented the algal-flora, -biomass and genetic features of dominant cells collected from temporary ponds around the Polar Research Station (PRS), Norway. Water samples were collected from 4 stations around PRS, and analyzed for their environmental and biological variables. Water temperature, salinity and conductivity ranged from 5 to $10^{\circ}C$, 0.1 to $0.3%_{\circ}$ and 0.21 to $0.36{\mu}S/cm$, respectively. Chlorophyll a concentration ranged from 1.8 to $11.1{\mu}g/l$, and that of the size-fractionated cells was recorded from 0.7 to $1.1{\mu}g/l$ in picoplankton 0.3 to $6.5{\mu}g/l$ in nanoplankton, and 0.4 to $3.9{\mu}g/l$ in microplankton respectively. Algal flora in the present study was recorded as 10 genera, in which Chlamydomonas, particularly, was dominant in all studied sites. By comparison of Chlamydomonas 18S rDNA sequences, including two isolates from PRS, they formed a distinct clade against others: sequence similarity was significantly low (<97.2%) with C. noctigama, being the highest score by BLAST search in GenBank. This study was valuable for basic knowledge regarding the freshwater algae around PRS and their genetic information.

• 미생물학회지
• /
• 제30권3호
• /
• pp.225-231
• /
• 1992

생물체내의 ascorbic acid :dehydroascorbic acid system 을 조절하는데 관여하는 것으로 알려진 ascorbate 산화효소의 활성을 단세포 녹조류인 Chlamydomonas reinhardtii 에서 확인함으로써 이 효소의 존재와 특성을 고찰하였다. 조효소는 native gel 전기 영동에 의한 활성 염색과 분광광도계에 의한 ascorbic acid .의 흡광도 감소 측정에서 뚜렷한 활성을 나타내었다. 황산암모늄 침전, hydroxyapatite 흡착 크로마토그래피, 그리고 Sephadex G-150 gel 여과 크로마토그래피 분리한 결과 26.1 units/mg /의 specific activity 를 나타내었다. 분리된 ascorbate 산화효소는 $55^{\circ}C$, pH 4.6 에서 가장 활성도가 높았다. Native gel 전기 영동에서 88,000 dalton 갸량의 분자량을 가지고 있었고 소단위체의 분자량을 55,000 이었다. 또한 Western bloting technique 을 이용하여 C. reinhardtii 의 ascorbate oxidase를 확인하였다.

• 한국물환경학회지
• /
• 제21권5호
• /
• pp.535-540
• /
• 2005

This study was conducted to evaluate the chlorinated disinfection by-products formation potential (DBPFP) produced from the cell and extracellular product (ECP) of Chlamydomonas pulsatilla after chlorination. Reaction yields of DBPs produced by C. pulsatilla of ECP and the cell were $0.007{\mu}mol/mg{\cdot}C$ and $0.808{\mu}mol/mg{\cdot}C$ respectively, Also, SUVA values of ECP and the cell were measured as $0.313L/mg{\cdot}m$ and $1.052L/mg{\cdot}m$ respectively, The DOC of cell was found to be lower than that of ECP, while the SUVA value and reaction yields for the cell were higher than those of ECP. For ECP, most of the DBPFP was composed of trihalomethanes (THM; 47.3%) and haloacetonitriles (HAN; 38,83%). THM and HAN were the major DBPFP produced by the cell. Chloroform was found to be the major THM compound; 98.3% for ECP and 99.98% for the cell. Dichloroacetic acid (DCAA) and dichloroacetonitrile (DCAN) were identified as the major haloacetic acid (HAA) and HAN compounds formed by ECP and the cell as a precursor, respectively. As the chlorine dose was increased, concentrations of DOC, THMs, and HANs were increased. However, the chlorine dose decreased the concentration of chlorophyll-a.

• Journal of Plant Biotechnology
• /
• 제34권4호
• /
• pp.307-312
• /
• 2007

클라미도모나스 (Chlamydomonas reinhardtii)에서 Tombus 바이러스의 p19 유전자가 RNAi suppressor로서 기능하는 지는 조사하기 위하여 형질전환을 수행하였다. Southern분석을 통하여 p19 유전자가 1 copy에서 여러 copy로 도입된 형질전환체를 선발하였다. MAA7 유전자의 3'UTR 부위의 inverted repeat (IR) DNA가 형질전환되어 제작된 #33 strain을 p19유전자로 다시 형질전환 한 결과, MAA7 mRNA의 발현 양이 변하여 일정하지 않고 교란되었으며, 5-FI가 첨가된 배지에서 증식이 저해되었다. 증식이 저해된 것은 p19 유전자에 의한 silencing의 suppression이 일어난 것으로 간주할 수 있다. 그러나 MAA7 mRNA의 발현양이 전반적으로 증가하지 않고 발현양의 교란이 일어났으므로 p19 유전자에 의한 silencing의 suppression으로 보기 어렵다. 따라서 본 연구에 사용된 p19 유전자가 클라미도모나스에서는 codon usage가 상이하여 단백질 발현양이 충분치 않아서 silencing의 suppression을 완전하게 하지 못하거나 고등식물에서 일어나는 방식과는 다른 방식으로 suppression한다고 할 수 있다.

• 한국수소및신에너지학회논문집
• /
• 제15권4호
• /
• pp.309-316
• /
• 2004

Chlamydomonas reinhardtii UTEX 90 was cultivated with continuous supply of 2% $CO_2$ using TAP media at $25^\circ{C}$ and produced biomass 1.18 g of dry cell weight/L for 4 days. C. reinhardtii algal biomass(CAB) was concentrated to 20 times by volume and converted into hydrogen and organic acids by anaerobic fermentation using Clostridium butyricum. Organic acids in the fermentate of CAB were consecutively used to produce hydrogen by Rhodobacter sphaeroides KD 131 under the light condition. Approximately 52% of starch in the concentrated CAB which had 4-5.8, 24-26 and 6-7 g/L of starch, protein and fat, respectively was degraded by Cl. butyricum at $37^\circ{C}$. During this process, hydrogen and some organic acids, such as formate, acetate, propionate, and butyrate, respectively were produced. Further conversion of the organic acids in anaerobic fermentate of CAB by Rb. sphaeroides KD131 produced hydrogen from the anaerobic fermentate under the illumination of 8 klux using halogen lamp at $30^\circ{C}$. The result showed that hydrogen was evolved by the anaerobic conversion using Cl. butyricum and then by the photosynthetic fermentation using Rb. sphaeroides KD131. It indicated that the two-step conversion process produced the maximum amount of hydrogen from algal biomass which contained carbohydrate, protein, and fat via organic acids.

• 한국유기농업학회지
• /
• 제22권4호
• /
• pp.743-760
• /
• 2014

본 연구는 유기농업에서 생물자원으로서 담수 클로렐라의 활용 가능성을 연구하고자 유기농 생태계로부터 담수 녹조류를 분리, 동정하고, 생물학적인 특성을 조사하였다. 조사 지역의 수온은 $12.4{\sim}28.2^{\circ}C$, pH는 6.1~8.5이었다. 담수 녹조류를 분리할 때 고체배양법이 액체배양법보다 오염도가 낮고 분리 빈도가 높았다. 전국 9개 지역, 6개 담수 녹조류 서식처로 부터 총 115개의 균주를 분리하였다. 담수 녹조류의 분리 및 배양을 위해 질소원으로는 $NaNO_3$과 $KNO_3$, 탄소원으로 $Na_2CO_3$를 사용하였고, macro media의 구성 성분 중 $MgSO_4{\cdot}7H_2O$과 $CaCl_2{\cdot}2H_2O$를 분리하여 제조한 BGMM(BG11 Modified Medium)배지를 고안하였다. 담수녹조류는 배양 후 4일째부터 급격히 흡광도가 증가하였고 8일째부터 흡광도가 감소하였다. 공시한 7개의 균주 중 CHK008 균주가 배양 7일째에 가장 높은 흡광도를 보였다. 담수 녹조류 배양에 적합한 BGMM 배지의 pH는 6~7이었고 조사되는 빛이 강할수록 생육이 증가하였으며 5종류 당류 중에서 Glucose와 Galactose를 첨가하였을 때 클로랄라의 생육이 좋았다. 순수 분리한 16개 녹조류 균주의 균총색은 녹색, 진녹색, 연녹색을 나타내었고, 11개의 균주가 형광현미경하에서 강한 형광 빛을 나타내었다. 녹조류 16개 균주의 형태적인 특징을 조사한 결과 C. vulgalis, C. sorokiniana, C. pyrenoidosa, C. kessleri, C. emersonii, and Chlamydomonas sp.의 2개 속 6개종으로 동정되었다. 담수 녹조류의 세포 크기는 종마다 다양한 변이를 보였다. 대부분의 담수 녹조류의 세포형태는 구형이었다. Chlamydomonas sp.는 타원형이었고 Chlorella sorokiniana는 구형과 타원형이 섞여 있었다. 6개 녹조류 종류 중 Chlamydomonas sp.를 제외한 모든 균주는 편모가 없었다. Chlamydomonas sp. 1개 균주와 C. sorokiniana 5개 균주는 세포에서 점질물을 분비하였다.