EonSeon Jin

Xanthophylls are oxygenated carotenoids that serve a variety of functions in photosynthetic organisms and are essential for survival of the organism. Within the last decade, major nor advances have been made in the elucidation of the molecular genetics and biochemistry of the xanthophyll biosynthesis pathway. Microalgae, yeast, or other microorganisms produce some of the xanthophylls that are being commercially used due to their own color and antioxidant properties. Currently, only a few microal

Unicellular gren algae of the genus Haematococcushave been studied extensively as model organisms for secondarystrong irradiance or nitrogen deficiency, unicellular gren algaeof the genus Haematococcus accumulate secondary carotenoidsin vesicles in the cytosol. Because secondary carotenoidaccumulation occurs only upon specific environmental stimuli,there is speculation about the regulation of the biosyntheticpathway specific for secondary carotenogenesis. Because thecarotenoid biosynthesis pathw

In this study, a cDNA microarray was developed from over 60,000 mRNA readings to analyze the expression profiles of transcriptomes of Haematococcus lacustris under astaxanthin-inducing culture conditions,high irradiance and nitrate starvation. Among 20,033 genes on the cDNA microarray, 2,675 genes exhibited a twofold or greater difference in expression. Of these, 1,333 genes were up-regulated and 1,342 genes were down-regulated. A significant decrease in the expression of chlorophyll biosynthesi

We present a rapid biogenic method for the production of nanoscale gold particles using pear extract. The formation and stability of pear-derived gold nanoparticles (Pear-AuNPs) were monitored by ultraviolet-visible spectroscopy. Their morphology, elemental composition and crystalline phase were determined by transmission electron microscopy, energydispersive X-ray spectroscopy and selected area electron diffraction. The average core size of crystalline Pear-AuNPs was in the range of 10 ± 5 nm a

Dunaliella salina and Dunaliella bardawil are well known for carotenogenesis, the overproduction of carotenoids, under stress conditions. The effect of high light (HL) and low light (LL) on the growth, morphology, photosynthetic efficiency, and the β-carotene and zeaxanthin production of D. salina CCAP 19/18 and D. bardawil was investigated and compared. Both strains showed similar growth kinetics under LL growth condition, but D. salina CCAP 19/18 was faster. As the light intensity increased, D

Zeaxanthin is an important pigment in the photo-protection mechanism of microalgae. However, zeaxanthin epoxidase, an enzyme involved in the accumulation and conversion of zeaxanthin, has not been extensively studied in microalgae. In this work, we report the expression pattern of zeaxanthin epoxidase in Dunaliella tertiolecta (DtZEP) at different light and diverse salinity conditions. To confirm the responsiveness to light conditions, the ZEP expression pattern was investigated in photoperiodic

Under environmental stress, such as strong iradianceor nitrogen deficiency, unicellular green algae of the genusHaematococus accumulate secondary carotenoids, i.e. astaxanthin,in the cytosol. The induction and regulation of astaxanthinbiosynthesis in microalgae has recently received considerableattention owing to the increasing use of secondary carotenoidsas a source of pigmentation for fish aquacultures, and as apotential drug in cancer prevention as a fre-radical quencher.Accordingly, this stu

Non-food-based biofuel feedstocks are in high demand worldwide. Among the various feedstocks, microalgae are the most promising feedstock for mitigating atmospheric CO2 and producing biodiesel. In this study, various concentrations of CO2, from 0.03 to 12%, were used to investigate their effect on the cell growth, biomass and lipid production and fatty acid composition of Dunaliella sp. in a closed photobioreactor. The results showed that the highest biomass and total lipids, 521 mg/L/d and 40 m

We investigated high light-induced alterations in antioxidant enzymes by exposing green vegetative cells of the alga Haematococcus pluvialis to excess irradiance to induce the production of astaxanthin, a carotenoid pigment. Total activity of catalase decreased approximately 70% after high light exposure, whereas glutathione peroxidase (GPX) activity was slightly enhanced. Total activity of superoxide dismutase and ascorbate peroxidase (APX) also slightly decreased. Overall, we did not observe d

A series of naphthoquinone-benzothiazole conjugates were synthesized as algicides, and their efficacies against harmful algal blooming species, such as Chattonella marina, Heterosigma akashiwo and Cochlodinium polykrikoides,were examined. The introduction of substituted benzothiazole at the C2 position of 1,4-naphthoquinone (compounds 1–9) resulted in higher algicidal activity against C. polykrikoides than the C6 conjugates (compounds 10–20). On the other hand, of the C6 conjugates, compounds 11

To increase the availability of microalgae as producers of valuable compounds, it is necessary to develop novel systems for gene expression regulation. Among the diverse expression systems available in microalgae, none are designed to induce expression by low temperature. In this study, we explored a cold-inducible system using the antifreeze protein (AFP) promoter from a polar diatom, Chaetoceros neogracile. A vector containing the CnAFP promoter (pCnAFP) was generated to regulate nuclear gene

Emiliania huxleyi (a haptophyte) is the most abundant coccolithophore species that produces delicate calcite scales called coccoliths. In this study, we identified several candidate genes associated with coccolith production by comparing the transcriptomes of the calcifying (CCMP 371) and non-calcifying (CCMP 2090) strains of E. huxleyi. Among the candidates, genes highly expressed in CCMP 371 were identified. To confirm whether these genes are associated with calcification, we modulated coccoli

Emiliania huxleyi is a marine phytoplankton that plays a critical role in global carbon and sulfur cycling. The genome of E. huxleyi has been sequenced, and an in-depth proteomic profile of this organism has been reported. This study analyzed the phosphoproteome of E. huxleyi and identified its changes under calcium-limited conditions. A TiO 2 microcolumn was used for phosphopeptide enrichment, followed by liquid chromatography-tandem mass spectrometry analysis. Overall, we identified 7,010 phos

Microalgae, as photosynthetic organisms, possess the ability to produce a diverse array of bioactive compounds. This study focused on the transformant Chlamydomonas reinhardtii dZL and subjected it to cultivation under varying light intensities (60, 120, 180, and 240 μmol/m2/s). Our aim was to assess the impact of light intensity on both microalgal biomass and carotenoid production. The cultivation took place in 80 mL bubble column photobioreactors, specifically the Multi-cultivator. Notably, th

Fragilariopsis cylindrus is one of the most successful psychrophiles in the Southern Ocean. To investigate the molecularmechanism of biomineralization in this species, we attempted to synchronize F. cylindrus growth, since new cell wallformation is tightly coupled to the cell division process. Nutrient limitation analysis showed that F. cylindrus culturesrapidly stopped growing when deprived of silicate or light, while growth continued to a certain extent in the absence ofnitrate. Flow cytometry