Jun Cheul Ahn

Cloning of a cDNA probably encoding oxidosqualene cyclase associated with asiaticoside biosynthesis from Centella asiatica (L.) Urban

A homology-based PCR method was used to clone a cDNA encoding oxidosqualene cyclase from Centella asiatica, which produces a large quantity of triterpene saponins such as asiaticoside and madecassoside. Sequence analysis of one clone found sequences related to β-amyrin synthase. An open reading frame in the full-length clone was named CabAS (Centella asiatica putative β-amyrin synthase). On the basis of amino acid sequence, CabAS appears to be an enzyme (β-amyrin synthase) that synthesizes β-amyrin. Southern analysis showed that the C. asiatica genome contains one copy of the CabAS gene. Northern blot analysis demonstrated that the CabAS gene is expressed in leaves with no detectable transcript in other plant tissues, consistent with the organ-specific accumulation of the asiaticoside. Up-regulation of expression of CabAS by methyl jasmonate in leaves was also demonstrated.

Polyacetylenes in hairy roots of Platycodon grandiflorum

Abstract Hairy roots of Korean balloon flower (Platycodon grandiflorum) were induced from root tissues infected with Agrobacterium rhizogenes ATCC 15834. Growth and polyacetylene (lobetyol, lobetyolin and lobetyolinin) production of 10 hairy roots clones cultured in 1 4 Gamborg B5 (B5) liquid medium were determined. One selected hairy root clone (D6) grew well in hormone-free B5 liquid medium and showed maximum content of polyacetylenes at week 6 for lobetyol (0.375% dry wt) and at week 7 for lobetyolin and lobetyolinin (3.030 and 0.206% dry wt, respectively) whose levels were much higher than those of the intact plant root (lobetyol: 0.019%; lobetyolin: 0.077% dry wt; lobetyolinin was not detected).

Overexpression of OsCYP19-4 increases tolerance to cold stress and enhances grain yield in rice (Oryza sativa)

Highlight OsCYP19-4 is a novel apoplastic immunophilin that plays a role in developmental acclimation and cold stress, probably via regulation of auxin transport.

Optimization of the sucrose and ion concentrations for saikosaponin production in hairy root culture ofBupleurum falcatum

Saikosaponin productivity was examined in aBupleurum falcatum L. BFHR2 hairy root culture in response to changes in the sucrose content (2≈8%), nitrogen content (0≈250 mM NH4NO3), phosphate content (0≈12 mM NaH2PO4), and the potassium content (0≈87.2 mM KCl) of the culture media. We found that the conditions for maximal saikosaponin production differed from those for optimal root growth. Highest saikosaponin yield was achieved for 8% sucrose, 62 mM NH4NO3, 1.2 mM NaH2PO4, and 0.5 mM KCl.

Seasonal variations in yields of Hwangchil lacquer and major sesquiterpene compounds from selected superior individuals ofDendropanax morbifera Lév.

We studied fluctuations in the production of Hwangchil lacquer and major essential oils byDendropanax morbifera Lev. Considerable seasonal as well as intraspecific (individual-tree) variations were observed. Yields of Hwangchil lacquer as well as ß-elemene, α-selinene, ß-selinene, germacrene D, and δ-cadinene also depended on harvesting time, with levels being generally higher in July and August.

An Evaluation of Major Nutrients of Four Farmed Freshwater Eel Species (Anguilla japonica, A. rostrata, A. bicolor pacifica and A. marmorata)

민물장어의 전 세계적인 양식규모는 1950년과 2007년 사이 에 거의 20배 증가하였다 (Crook, 2010). 하지만 인공부화를 통 한 양식종묘의 양산체계가 확립되지 않은 상태에서 이러한 양 식규모의 확대는 자연산 치어의 남획과 함께 극동아시아의 주 요 양식어종인 Anguilla japonica의 실장어(glass eels) 채포량 의 급격한 감소를 초래하게 되었다(Lee, 2014; Tzeng, 2014). 실장어 채포량의 감소는 실장어 가격, 양식 생산비 및 소비자 가격의 상승으로 이어져 민물장어 양식산업의 수익성이 한계 에 이르고 있다. 이에 대한 대안으로 한국, 중국, 일본 및 대만 등 아시아 민물장어 양식국가들은 1990년대 후반부터 온대성 장어로 실장어의 가격이 보다 저렴한 유럽산 민물장어인 A. anguilla 실뱀장어 양식이 이루어지기도 하였다(Ringuet et al., 2002). 하지만, 2007년 Conversion on Internatonal Trade in Endnagered Species of Wild Flora and Fauna (CITES) (멸 종위기에 처한 야생동식물종의 국제거래에 관한 협약) 보호종 에 유럽산 민물장어(A. anguilla)가 포함되었고 북미산 장어(A. 국내양식 민물장어 4 종(Anguilla japonica, A. rostrata, A. bicolor pacifica 및 A. marmorata)의 주요 영양성분의 평가

Overexpression of Golgi Protein CYP21-4s Improves Crop Productivity in Potato and Rice by Increasing the Abundance of Mannosidic Glycoproteins

CYP21-4 is a novel Golgi-localized cyclophilin protein involved in oxidative stress tolerance. Here, we generated transgenic plants overexpressing AtCYP21-4 and OsCYP21-4 in potato and rice, respectively. The stems and roots of AtCYP21-4–overexpressing potato plants were longer than those of wild-type (WT) plants, which resulted in heavier tubers. In vitro tuberization in the transgenic potato also resulted in significantly greater tuber number and weight, as well as a shorter time to microtuber formation. Similarly, OsCYP21-4–overexpressing transgenic rice plants had higher biomass and productivity with longer early-stage internodes than the WT and higher seed weight. Immunoblot analysis with CYP21-4 antibody showed that these productivity-enhancing phenotypes were associated with high CYP21-4s protein expression. Anatomically, transgenic potato stems exhibited higher lignin content in xylem cells and thicker leaves. In addition, relative content of mannosidic glycoproteins per unit of total protein was above 20% in transgenic potato tubers and rice grains. Based on these findings, we propose that CYP21-4s are involved in the growth and development of plant vegetative and storage tissues via their effects on glycoprotein abundance or glycan processing in the Golgi apparatus. Thus, increasing CYP21-4s expression in crops could represent an alternative way to increase crop productivity and yield.