Hee-Mock Oh is currently a Senior Research Scientist at the Korea Research Institute of Bioscience and Biotechnology (KRIBB). His research has centered upon ecophysiological and molecular aspects of microalgae, notably control of cyanobacterial bloom, monitoring of cyanobacterial toxins and biodiesel production by mass-cultivation of microalgae. He is President of the Korean Society of Phycology (2014-2015) and a Fellow of the Korean Academy of Science and Technology (KAST).
The oleaginous microalga, Ettlia sp. YC001 was isolated from Daejeon, South Korea and was classified to class Trebouxiophyceae based on 18S rRNA gene sequences. The average lipid content was found to be 20-30%. However, maximum lipid contents were increased upto ~55% under the stress conditions. The whole genome of the strain has been sequenced with Illumina and PGM machine and annotated by Augustus, Glimmer HMM and PASA as Ab initio gene predictors and pipeline, respectively. The genome was about ~170 Mbp with ~20,658 genes. The complete mitochondrial genome was 52,490 bp with GC contents of 48% and 58 genes. Through physiological characterization and transcriptome analysis we found that the carotenoids composition and quality depended on stress condition such as highlight, deficiency of nitrogen, magnesium, calcium and iron. We also identified the expression of different genes and key enzymes involved in the carotenoid synthesis pathway in young and senescent cells. The dominant carotenoids were lutein and neoxanthin. However, these were gradually decreased with time whilst cantaxanthin and antherazanthin were steadily accumulated. Thus, Ettlia sp. YC001, a natural source of carotenoids as well as high accumulated lipid seems to be suitable for industrial application to produce both biodiesel and high-value compounds. Additionally, genomic information will provide valuable clues to drive commercialization of microalgae for the maximum production of lipid and carotenoids through genetic modification.
Raoufa A I Abdel Rahman has completed her PhD in 2003 at Alexandria University, Faculty of Agriculture, Genetics Department through a collaborative scholarship with University of Georgia, Athens, USA. She completed a research project entitled ‘Exploring IRES mediated discistrons for the phytoremediation of Mercury’. Currently, she is the Director of Pharmaceutical Bio-products Research Department, City of Scientific Research and Technology Applications, Egypt. Her main research interests are using plant tissue culture and genetic engineering techniques to conserve rare and endangered plant species as well as enhancement of the productivity of important pharmaceutical compounds from plants. She is working in several projects dealing with the production of antiviral, anticancer and antioxidant compounds from plants using in vitro cultures.
Plants are important source for natural drugs and modern medicines; it is estimated that approximately one quarter of prescribed drugs contain plant extracts or active ingredients obtained from plant substance. Silybum marianum (L) Gaernt is a member of the family Asteraceae native to the Mediterranean area. The plant extract has anticancer, anti-inflammatory, antioxidant, hepatoprotective, antidiabetic and immune-modulatory effects. In the present study, callus cultures obtained from leaf explants using MS medium supplemented with 1 mg/l BA and 1 mg/l 2,4-D. Effects of sodium azide and gamma rays on callus growth and silymarin production were tested. Callus treated with 1,2,3,4 or 5 mM NaN3 for 1 hour or exposed to γ-radiation at doses of 10, 20, 30, 40 or 50 Gray. Results indicated that the fresh weight of treated callus decreased by increasing the dose of NaN3 and γ-rays. The chemical composition of silymarin was determined by HPLC. Sodium azide and gamma rays could induce the production of isosilybin A that was not detected in control callus. They reduced or enhanced the production of other silymarin components. Differential display technique was used to identify differentially expressed genes associated with silymarin production. Nine unique cDNAs over-expressed in treated callus and representative of suspected genes that expressed due to mutagen stress were purified and sequenced. Most of the obtained nucleotide sequence and corresponding amino acid displayed 100% similarities to chalcone synthase that is a key enzyme in flavonolignans biosynthesis. The over-expression of chalcone synthase may be the cause of enhanced production of some silymarin components.