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Wang, Hui,Sathasivam, Ramaraj,Ki, Jang-Seu The Korean Society of Phycology 2017 ALGAE Vol.32 No.2
Although green algae of the genus Closterium are considered ideal models for testing toxicity in aquatic ecosystems, little data about the effects of toxicity on these algal species is currently available. Here, Closterium ehrenbergii was used to assess the acute toxicity of copper (Cu). The median effective concentration ($EC_{50}$) of copper sulfate based on a dose response curve was $0.202mg\;L^{-1}$, and reductions in photosynthetic efficiency ($F_v/F_m$ ratio) of cells were observed in cultures exposed to Cu for 6 h, with efficiency significantly reduced after 48 h (p < 0.01). In addition, production of reactive oxygen species significantly increased over time (p < 0.01), leading to damage to intracellular organelles. Our results indicate that Cu induces oxidative stress in cellular metabolic processes and causes severe physiological damage within C. ehrenbergii cells, and even cell death; moreover, they clearly suggest that C. ehrenbergii represents a potentially powerful test model for use in aquatic toxicity assessments.
Hui Wang,Ramaraj Sathasivam,기장서 한국조류학회I 2017 ALGAE Vol.32 No.2
Although green algae of the genus Closterium are considered ideal models for testing toxicity in aquatic ecosystems,little data about the effects of toxicity on these algal species is currently available. Here, Closterium ehrenbergii was usedto assess the acute toxicity of copper (Cu). The median effective concentration (EC50) of copper sulfate based on a dose responsecurve was 0.202 mg L-1, and reductions in photosynthetic efficiency (Fv / Fm ratio) of cells were observed in culturesexposed to Cu for 6 h, with efficiency significantly reduced after 48 h (p < 0.01). In addition, production of reactive oxygenspecies significantly increased over time (p < 0.01), leading to damage to intracellular organelles. Our results indicate thatCu induces oxidative stress in cellular metabolic processes and causes severe physiological damage within C. ehrenbergiicells, and even cell death; moreover, they clearly suggest that C. ehrenbergii represents a potentially powerful test modelfor use in aquatic toxicity assessments.
Park Woo Tae,Yeo Sun Kyung,Sathasivam Ramaraj,Park Jong Seok,Kim Jae Kwang,Park Sang Un 한국응용생명화학회 2020 Applied Biological Chemistry (Appl Biol Chem) Vol.63 No.3
Agsatache rugosa (Korean mint), belongs to the mint family and it has various medicinal properties. In addition, it has several valuable compounds such as monoterpenes and phenylpropanoid compounds. Amongst these, two compounds viz., rosmarinic acid (RA), and tilianin are well-known natural compounds that have numerous pharmacological properties. The phenylpropanoid biosynthetic gene expression under stress conditions and the subsequent accumulation of phenylpropanoid content has not been extensively studied in Korean mint. Here, we investigated the effect of light-emitting diodes (LEDs) on the expression levels of phenylpropanoid biosynthetic pathway genes and the accumulation of phenylpropanoid compounds such as RA and tilianin in A. rugosa. Real-time PCR analysis showed that the phenylpropanoid pathway genes responded to the LED lights. The transcript levels of downstream genes (C4H, CHS, CHI, and RAS) were comparatively higher than those of upstream genes (PAL, TAT , and HPPR). In addition, HPLC analysis showed that the content of RA and tilianin were significantly higher in plants cultivated under white light than those grown under red, blue, green, and orange lights. The RA and tilianin content were the highest in the plantlets after three weeks of exposure to white light. These results suggested that white LED lights significantly enhanced the accumulation of phenylpropanoid compounds in A. rugosa.
Yeo Hyeon Ji,Baek Seung-A,Sathasivam Ramaraj,Kim Jae Kwang,Park Sang Un 한국응용생명화학회 2021 Applied Biological Chemistry (Appl Biol Chem) Vol.64 No.1
This study aimed to comprehensively analyze primary and secondary metabolites of three different-colored (white, pale green, and green) pak choi cultivars (Brassica rapa subsp. chinensis) using gas chromatography attached with time-of-flight mass spectrometry (GC-TOFMS) and high-performance liquid chromatography (HPLC). In total, 53 primary metabolites were identified and subjected to partial least-squares discriminant analysis. The result revealed a significant difference in the primary and secondary metabolites between the three pak choi cultivars. In addition, 49 hydrophilic metabolites were detected in different cultivars. Total phenolic and glucosinolate contents were highest in the pale green and green cultivars, respectively, whereas total carotenoid and chlorophyll contents were highest in the white cultivar. Superoxide dismutase activity, 2,2-diphenyl-1-picrylhydraz scavenging, and reducing power were slightly increased in the white, pale green, and green cultivars, respectively. In addition, a negative correlation between pigments and phenylpropanoids was discovered by metabolite correlation analysis. This approach will provide useful information for the development of strategies to enhance the biosynthesis of phenolics, glucosinolates, carotenoids, and chlorophyll, and to improve antioxidant activity in pak choi cultivars. In addition, this study supports the use of HPLC and GC-TOFMS-based metabolite profiling to explore differences in pak choi cultivars.