• Journal of Plant Biology
• /
• 제37권1호
• /
• pp.101-109
• /
• 1994

Chlamydomonas reinhardtii 배우체 유도기 동안에 polyamine 생합성 억제제인 MGBG[methylglyoxal bis-(guanylhydrazone); SAMDC 억제제] 1mM 처리구와 정상 대조구에서의 polyamine 함량 변화와 Chlamydomonas의 ct-DNA methylation과의 상호 연관성을 조사한 결과, 전반적으로 137C(＋)와 137C(-)의 정상 대조구에서 polyamine 수준은 배우체 유도기 전반에 걸쳐서 감소추세로 나타났으나, 특히 137C(＋)가 137C(-)보다 polyamine 함량이 많았으며 동시에 감소량도 컸다. 1mM MGBG 처리구에서는 137C(＋)의 spermidine 함량이 정상 대조구보다 증가하였다. In vitro에서 ctDNA methylation에 대한 MGBG의 영향은 정상 대조구에서보다도 1mM MGBG 처리구에서 약 20-30%의 ctDNA methylation 감소를 나타내었다. 또한, MGBG는 in vitro에서 DNA methylase에 대하여 억제효과를 나타내어TEk.

• 한국산학기술학회논문지
• /
• 제14권8호
• /
• pp.4086-4092
• /
• 2013

Mycosporine-like 아미노산(MAAs)은 UV 흡수물질이며, 다양한 해양생물들은 MAAs의 합성과 축적을 통하여 환경 자외선의 직 간접적인 영향을 감소시키는 기능을 진화시켜 왔다. 이 연구에서 우리는 radiofrequency(RF) 발생장치를 제작하였고, 이를 미세조류 배양에 적용하였다. $0.35{\pm}0.05$ mHz의 RF를 Chlamydomonas sp. 배양기에 공급하였고, 정해진 시간(0, 0.5, 1 및 2 시간)에 시료를 채취하였다. MAAs 생합성 관련 유전자인 dehydroquinate synthase homolog (DHQS-like)와 nonribosomal peptide synthetase homolog (NRPS-like) 유전자를 Chlamydomonas sp.로부터 클로닝하였고, RF 노출에 대한 유전자 발현을 qRT-PCR을 이용하여 분석하였다. 연구결과 RF에 노출된 Chlamydomonas sp.의 DHQS-like와 NRPS-like 유전자의 발현은 노출 1시간에 각각 1.46 배 및 1.19 배 증가하였다. 이러한 결과는 DHQS-like와 NRPS-like 유전자가 Chlaydomonas sp.의 MAAs 생합성을 진단할 수 있는 좋은 바이오마커 후보가 될 수 있음을 의미한다.

• Journal of Microbiology and Biotechnology
• /
• 제25권5호
• /
• pp.723-731
• /
• 2015

Microalgae hold promise as producers of sustainable biomass for the production of biofuels and other biomaterials. However, the selection of strains with efficient and robust production of desirable resources remains challenging. In this study, we isolated a green microalga from Korea and analyzed its morphological, molecular, and biochemical characteristics. Microscopic and phylogenetic analyses demonstrated that the isolate could be classified into the genus Chlamydomonas, and we designated the isolate Chlamydomonas sp. KIOST -1. Compositions of protein, lipid, and carbohydrate in the microalgal cells were estimated to be 58.8 ± 0.2%, 22.7 ± 1.2%, and 18.5 ± 1.0%, respectively. Similar to other microalgae belonging to Chlorophyceae, the dominant amino acid and monosaccharide in Chlamydomonas sp. KIOST-1 were glutamic acid and glucose. On the other hand, the proportions of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids clearly differed from other species in the genus Chlamydomonas, and monounsaturated fatty acids accounted for a large portion (41.3%) of the total fatty acids in the isolate. Based on these results, Chlamydomonas sp. KIOST-1 has advantageous characteristics for biomass production.

• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2005년도 수소연료전지공동심포지움 2005논문집
• /
• pp.365-368
• /
• 2005

• Journal of Microbiology and Biotechnology
• /
• 제28권7호
• /
• pp.1217-1224
• /
• 2018

Seaweeds produce antioxidants to counteract environmental stresses, and these antioxidant genes are regarded as important defense strategies for marine algae. In this study, the expression of Pyropia yezoensis (Bangiales, Rhodophyta) ascorbate peroxidase (PyAPX) and manganese-superoxide dismutase (PyMnSOD) was examined by qRT-PCR in P. yezoensis blades under abiotic stress conditions. Furthermore, the functional relevance of these genes was explored by overexpressing them in Chlamydomonas. A comparison of the different expression levels of PyAPX and PyMnSOD after exposure to each stress revealed that both genes were induced by high salt and UVB exposure, being increased approximately 3-fold after 12 h. The expression of the PyAPX and PyMnSOD genes also increased following exposure to $H_2O_2$. When these two genes were overexpressed in Chlamydomonas, the cells had a higher growth rate than control cells under conditions of hydrogen peroxide-induced oxidative stress, increased salinity, and UV exposure. These data suggest that Chlamydomonas is a suitable model for studying the function of stress genes, and that PyAPX and PyMnSOD genes are involved in the adaptation and defense against stresses that alter metabolism.

• Journal of Plant Biology
• /
• 제35권4호
• /
• pp.415-423
• /
• 1992

Chlamydomonas reinhardtii 21 gr(mt+) strain의 배우체로부터 두 종류의 DNA methylase를 부분 분리하여 몇가지 기질 DNA에 대한 효소 활성을 측정하였다. DNA methylase I과 II는 동일한 pH와 ionic strength에서 서로 상이한 물리적인 성질과 서로 다른 분자량을 가지며 DNA methylase I과 II는 모두가 DNA 염기 중 adenine보다는 cytosine에 methylation을 수행하는 것으로 생각된다. 합성 DNA를 사용한 실험에서 DNA methylase I과는 달리 DNA methylase II는 poly(dA-dC)·poly(dG-dT)에서 보다 poly(dG-dC)·poly(dG-dC)의 oligonucleotide에서 더 높은 효소활성을 나타내었다. Chlamydomonas reinhardtii에서 추출한 엽록체 DNA를 기질로 사용하였을 때 DNA methylase I과 II 모두가 배우체기 보다는 영양생장기의 엽록체 DNA에 더 높은 활성을 나타내었다.

• Journal of Plant Biology
• /
• 제33권4호
• /
• pp.293-301
• /
• 1990

We have purified and characterized a deoxyribonuclease from zygotes of the eukaryotic green alga, Chlamydomonas reinhardtii and investigated effects of the polyamines, putrescine, spermidine and spermine on the purifed endonuclease-catalyzed cleavage of plasmid DNA. The enzyme has a molecular weight of about 37 kDa as measured by gel filtration and SDS-polyacrylamide gel electrophoresis. There is no requirement for a divalent cation. The activity is sensitive to ionic strength, as NaCl and KCl result in inhibition. The cleavage of plasmid DNA by the purified endonuclease was effectively inhibited by polyamines. The enzyme activity was inhibited more effectively by spermine than by spermidine. The inhibition by putrescine was lower than the other two polyamines.

• KSBB Journal
• /
• 제30권2호
• /
• pp.91-95
• /
• 2015

Production of biodiesel from microalgae is dependent on the microalgal lipid content and free fatty acid composition. Both lipid and free fatty acid are regulated by nutrient sources. In this study, newly developed mutant Chlamydomonas reinhardtii with higher lipid content was investigated for the effect of nutrient limitation. Nitrogen $NO_3{^{-}}$ and phosphate $PO_4{^{3-}}$ were limited for nutrient starvation during the cultivation. Under nutrient starvation, total lipid content level was increased to 27~33% and C16:0 fatty acid content constituted over 31~43% of total fatty acid. Interestingly, we also found that the expression of fatty acid desaturase (FAD7) was decreased when nutrients were starved.

• BMB Reports
• /
• 제29권4호
• /
• pp.294-299
• /
• 1996

Glyoxalase I (Ee 4.4.1.5, lactoylglutathione lyase) from Chlamydomonas reinhardtii was purified to homogeneity by ammonium sulfate fractionation, anion-exchange chromatography, hydrophobic interaction chromatography, and affinity chromatography on S-hexylglutathione agarose. The purified enzyme was judged to be homogeneous on SDS-PAGE, and consisted of a single polypeptide chain with a relative molecular weight of 24,000. The enzyme was most active at $40^{\circ}C$ and pH 7.5. It was catalytically most active with methylglyoxal as substrate. A number of properties of the Chlamydomonas glyoxalase I enzyme, such as substrate specificity, molecular mass, kinetic parameters, pi, metal ion effect, have been determined and compared with those reported for preparations from other sources. It had somewhat different characteristics from mammalian enzymes.

• ALGAE
• /
• 제34권1호
• /
• pp.35-43
• /
• 2019

Genetic study of haploid organisms offers the advantage that mutant phenotypes are directly displayed, but has the disadvantage that strains carrying lethal mutations are not readily maintained. We describe an approach for generating and performing genetic analysis of diploid strains of Chlamydomonas reinhardtii, which is normally haploid. First protocol utilizes self-mating diploid strains that will facilitate the genetic analysis of recessive lethal mutations by offering a convenient way to produce homozygous diploids in a single mating. Second protocol is designed to reduce the chance of contamination and the accumulation of spontaneous mutations for long-term storage of mutant strains. Third protocol for inducing the meiotic program is also included to produce haploid mutant strains following tetraploid genetic analysis. We discuss implication of self-fertile strains for the future of Chlamydomonas research.