Young-Goo Park

Evaluation of the genetic diversity among elite tea (Camellia sinensis var. sinensis) accessions using RAPD markers

The diversity of 27 superior tea (Camellia sinensis var. sinensis) accessions from Korea, Japan and Taiwan was examined with RAPD-PCR (Random Amplified Polymorphic DNA Polymerase Chain Reaction) markers. Out of the 50 primers screened, 17 primers generated 58 polymorphic and reproducible bands. A minimum of 3 primers was sufficient to distinguish all the 27 accessions studied. The Shannons index used to partition diversity into inter- and intra-group, revealed that 71 percent of variability resided within groups and 29 percent between groups. Diversity was greatest within the Korean group followed by Taiwan and Japan. The relatively high diversity observed in Korea might reflect the larger genetic base of its plantations while the low diversity in Japan could be explained by the long and intensive tea selection programme in this country. A dendrogram based on the UPGMA-link method using Jaccards distances and multivariate Factorial correspondence analysis clustered the tea accessions into two main groups, regrouping the Taiwan cultivars on the one side and the Korean and Japanese accessions on the other side. This suggests that the Taiwan tea studied here may have a different origin from that of Korea and Japan.

Beneficial effects of Undaria pinnatifida ethanol extract on diet-induced-insulin resistance in C57BL/6J mice

This study was performed to evaluate the beneficial effect of Undaria pinnatifida ethanol extract (UEFx) on insulin resistance in diet-induced obese mice. A high-fat diet was supplemented with the UEFx at 0.69% (wt/wt) dose, which contains an equivalent amount of 0.02% fucoxanthin (wt/wt), or with Fx at 0.02% (wt/wt) dose in diet. After 9 weeks, both UEFx supplement significantly lowered the amount of visceral fat, the size of adipocyte, the fasting blood glucose concentration, the plasma insulin and the insulin resistance index similar to pure as shown by Fx supplement, compared to the high-fat (HF) control group. Blood glucose level was negatively correlated with hepatic glucokinase activity (r = -0.533, p < 0.05), whereas positively correlated with hepatic gluconeogenic enzyme activities (r = 0.463, p < 0.05 for glucose-6-phosphatase; r = 0.457, p < 0.05 for phosphoenolpyruvate carboxykinase). Ratio of hepatic glucokinase/glucose-6-phosphatase and glycogen content were significantly elevated by the UEFx and Fx supplements. Supplementation of the UEFx as well as Fx seemed to stimulate the β-oxidation activity and inhibit the phosphatidate phosphohydrolase activity resulting in a decrease in the hepatic lipid droplet accumulation. The results indicate that the UEFx can prevent insulin resistance and hepatic fat accumulation that is partly mediated by modulating the hepatic glucose and lipid homeostasis in the high fat-induced obese mice.

Production of ginkgolides and bilobalide from optimized theGinkgo biloba cell culture

The influence of various culture conditions on growth and ginkgolides (GKA and GKB), and bilobalide formation in callus and suspension cultures ofGinkgo biloba were investigated. Callus induced from the leaf petioles exhibited distinct morphological and physiological responses. The cell biomass and ginkgolides content varied among the cell lines brownish callus lines produced high levels of ginkgolides and bilobalide in spite of poor cell growth. Among the culture media used, MS medium showed significant effect on cell growth and ginkgolides production. Low concentration of sucrose (3%) improved cell growth, while higher sucrose levels (5 and 7%) improved ginkgolides production. Cultivation of callus cultures above 28°C dramatically reduced their growth rate; however the cell lines grown at 36°C showed increased levels of bilobalide content. A 2.5-L balloon type bubble bioreactor (BTBB) was successfully developed for the cell growth and ginkgolides production.

Variation of ginkgolides and bilobalide contents in leaves and cell cultures ofGinkgo biloba L.

Ginkgolides (GK) and bilobalide are valuable compounds that belong to the lactone terpene. The contents of these metabolites were determined by HPLC from female and male tree ofGinkgo biloba L. The productivity ofG. biloba cells was also compared with the corresponding individual trees. High variations in the ginkgolides and bilobalide were observed from different individuals, plant parts, and cultured cells. The ginkgolides and bilobalide contents were different depending on the plant parts. Callus was obtained from various plant tissues, and NAA was better at callogenesis than 2,4-D in both the female and male trees. The plants and their corresponding cells showed considerable variation in their ginkgolides and bilobalide concentrations. The ginkgolides and bilobalide contents were not correlated with the production between dominant trees and their corresponding cells. Light irradiation enhanced the production of GK-A and GK-B, however, the concentration of bilobalide decreased under dark conditions.

Taxol content in the seeds of Taxus spp.

Abstract The concentrations of taxol and related compounds in the mature dried seeds of several Taxus species were determined by HPLC. In addition, the taxol level of the seeds of T. cuspidata at different stages of maturation was studied. The variation in the taxane content was dependent on individual trees within species as well as among species. The average contents of taxol and its precursor, 10-deacetyl baccatin III (10-DAB III) in the mature seeds of different species were 67.3 ± 50 and 96.2 ± 83 μg g −1 dry wt, respectively. In mature seed parts of T. cuspidata var. latifolia obtained from tree U5, the embryo weight was ca 0.2% of that of the dry weight of the whole seed and contained the highest level of taxol (894 μg g −1 ) when compared with that obtained for the endosperm (23 μg g −1 ) and testa (376 μg g −1 ). However, the taxol content per seed was highest in the testa (20.5 μg) followed by the endosperm (0.75 μg) and embryo (0.18 μg). The taxol content of the fresh seed reached a maximum of 332 μg g −1 and 20 μg seed −1 at the middle stage of seed maturation and then decreased with further maturation. The taxol identification in the seed was confirmed by electrospray mass spectrometry.

Tea Plant ( Camellia sinensis ) Breeding in Korea

Tea plant was introduced into Korea from China more than 2,000 years ago in the Kaya Dynasty. During the Goryeo Dynasty (918 – 1392), the tea culture flowered along with Buddhism. However, it gradually declined until the 1980s, when a period of economic growth in Korea combined with a rapid recovery of the tea culture and industry. Scientific tea research in Korea began at Boseong in 1992. The results of these studies are not concluded regarding tea breeding, cultivation and manufacture. In 2004, a tea research laboratory was opened at Mokpo Experiment Station, National Institute of Crop Science, Rural Development Administration (RDA). Over 80% of the total Korean tea gardens are seedlings on mountain slopes consisting of individuals with various sprouting times and growth types causing low yield, inconsistent product quality, as well as difficult to use machinery. In order to solve this problem, it is necessary to develop and supply clonal cultivars with disaster-resistant, high quality and high yield features. Several clonal tea cultivars are already registered at Boseong Tea Experiment Station. A new strategy for shortening the process of clonal tea breeding, characteristic examination, clonal tests, local adaptability tests and propagation of promising lines has been carried out simultaneously at 6 local adaptability test stations. The highly adaptable clones will be selected for use throughout Korea.