Hyeon-Cheol Cha

Flavonoids from leaves and exocarps of the grape Kyoho

We analyzed and compared profiles of flavonols extracted from leaves and exocarps of the grape Kyoho by TLC, HPLC and UV spectrophotometry. In the exocarps, quercetin 3‐O‐glucoside was the main compound while isorhamnetin 3‐O‐glycoside (I) was present in minor amounts. In leaves, on the other hand, quercetin 3‐O‐glucoside and quercetin 3‐O‐glucoside‐7‐O‐glucronide were the major compounds while isorhamnetin 3‐O‐glycoside (II) and kaempferol 3, 7‐O‐diglycoside were present in minor amounts.

Effects of various pretreatments on seed germination ofCalystegia soldanella (Convolvulaceae), a coastal sand dune plant

We tested various pretreatments to enhance the germination of ‘Sea bells’ (Calystegia soldanella Roem. et Schult). One experiment, which improved the germination rate by 70%, involved first scarifying the seed coats, then immersing the seeds in 50 ppm GA3 for 24 h. A GA3-alone pretreatment did not increase germination. However, the most effective method, with a 100% success rate, included 3 h of acid pretreatment with 98% H2SO4. We also used scanning electron microscopy (SEM) to examine the seed-coat surfaces and cross-sections of dry seeds. SEM showed structural differences between seeds that were not treated and those exposed to 98% H2SO4. The latter treatment allowed the seed coats to crack and break, thereby disrupting their physical dormancy.

Flavonoid analysis ofHeloniopsis orientalis (Thunb.) by high performance liquid chromatography

We have isolated and identified seven flavonoid compounds from the foliar extracts ofHeloniopsis orientalis, a member of Liliaceae, which is habituated at Namhansanseong and Maranggol (Jinburyung). All are glycosylated derivatives of the flavonols isorhamnetin, kaempferol, and quercetin. Among them, quercetin 3-O-galactoside is the major compound, while isorhamnetin 3-O-arabinosylgalactoside, isorhamnetin 3-O-digalactoside, kaempferol 3,7-O-galactoside, kaempferol 3-O-arabinosylgalactoside, kaempferol 3-O-glycoside, and quercetin 3-O-arabinosylgalactoside are present in smaller amounts. Although the two populations do not differ significantly in their overall flavonol profiles, their relative amounts indicate that flavonoid levels, especially for isorhamnetin, are geographically controlled and specifically depend on the origin of the individual population.

Regeneration of grape (Vitis labruscana cv. Kyoho) by shoot-tip culture

We investigated the optimal levels of growth regulators, culture media, and pH on callus growth and organogenesis of in-vitro cultured ‘Kyoho’ grapes. Calli were induced by culturing leaf blades on an MS basal medium supplemented with 1 mg/IL BA and 0.01 mg/L 2,4-D. In addition, calli originating from the exocarp and mesocarp of grape fruits devel-oped on MS media supplemented with 0.1 mg/L IAA, NAA, or 2,4-D, or with 0.2 mg/L BA. In testing the potential for plant regeneration from shoot tips on various media, we found that the Nitsch medium, with I mg/L BA, was optimal for caulogenesis. The type of shoot development depended on the pH of the medium, with vigorous multiple-shoot devel-opment occurring at pH 6.0, and single shoots forming at pH 5.0. Finally, we were able to obtain rooted seedlings from the regenerated shoots that had been cultured on 1/4-strength Nitsch medium supplemented with 0.03 mg/L NAA.

Characterization of Impaired Cerebrovascular Structure in APP/PS1 Mouse Brains

Alzheimers disease (AD) is defined by senile plaques, tauopathy and neuronal cell death in specific area of the brain. Recent studies suggest that neurovascular dysfunction may be an integral part of AD pathogenesis, contributing to the onset and development of AD pathologies such as neuronal death, inflammatory response, and breakdown of blood-brain barrier (BBB). In addition, vascular complications caused by age-related metabolic diseases such as diabetes and high blood pressure have high incidence in development of dementia and AD. We previously reported that astrocytes, essential components of BBB, were chronically activated and some deteriorated in the brain of 5xFAD, an amyloid precursor protein/presenilin1 (APP/PS1) transgenic mouse model. Thus, it is rational to investigate if any vascular dysfunction is associated with considerable activation of astrocytes in APP/PS1 mouse model. In this study, we observed that cerebrovascular pathology was associated with large scale of reactive astrocytes and neurodegeneration in an Aβ plague-generating mouse model. Using 5xFAD mouse brains, we demonstrate damaged brain vessels and reduced expression of glucose transporter 1 (GLUT1), the main glucose transporter, and a tight junction protein zonula occludens-1 (ZO-1) of cerebrovascular endothelial cells. This vascular pathology was closely associated with astrocytic deterioration and neuronal loss due to buildup of Aβ plaques in 5xFAD mouse brains.

Roles of 5-HT on phase transition of neurite outgrowth in the identified serotoninergic neuron C1, Helisoma trivolvis

Neurite outgrowth is a morphological marker of neuronal differentiation and neuroregeneration, and the process includes four essential phases, namely initiation, elongation, guidance and cessation. Intrinsic and extrinsic signaling molecules seem to involve morphological changes of neurite outgrowth via various cellular signaling cascades phase transition. Although mechanisms associated with neurite outgrowth have been studied extensively, little is known about how phase transition is regulated during neurite outgrowth. 5-HT has long been studied with regard to its relationship to neurite outgrowth in invertebrate and vertebrate culture systems, and many studies have suggested 5-HT inhibits neurite elongation and growth cone motility, in particular, at the growing parts of neurite such as growth cones and filopodia. However, the underlying mechanisms need to be investigated. In this study, we investigated roles of 5-HT on neurite outgrowth using single serotonergic neurons C1 isolated from Helisoma trivolvis. We observed that 5-HT delayed phase transitions from initiation to elongation of neurite outgrowth. This study for the first time demonstrated that 5-HT has a critical role in phase-controlling mechanisms of neurite outgrowth in neuronal cell cultures.

PCR Technique for Determining Jeju Black Cattle, Hanwoo and Imported Beef

For the identification of the Jeju black cattle, Hanwoo and imported beef, we performed a multiplex polymerase chain reaction (PCR) associated with microsatellite (MS) and melanocortin 1 receptor (MC1R) gene. The MC1R gene plays an important role in regulation of the melanin synthesis within mammalian melanocytes. MC1R encoded by extension (E) locus was almost fixed with recessive red e allele in the Hanwoo. We estimated that the specific genotypes (E + /E + , E + /e) of MC1R gene were characteristic genotypes of Jeju black cattle. But the PCR products resulted from using the MC1R gene derived primers only are not sufficient to identify Jeju black cattle from other relatives. We performed two times of successive multiplex PCR to provide a more accurate result for the identification of Jeju black cattle. The results suggest that two types of successive multiplex PCR methods using MC1R gene and Microsatellite derived primer set will be more useful to identification of Jeju black cattle, Hanwoo and imported beef.For the identification of the Jeju black cattle, Hanwoo and imported beef, we performed a multiplex polymerase chain reaction (PCR) associated with microsatellite (MS) and melanocortin 1 receptor (MC1R) gene. The MC1R gene plays an important role in regulation of the melanin synthesis within mammalian melanocytes. MC1R encoded by extension (E) locus was almost fixed with recessive red e allele in the Hanwoo. We estimated that the specific genotypes (E + /E + , E + /e) of MC1R gene were characteristic genotypes of Jeju black cattle. But the PCR products resulted from using the MC1R gene derived primers only are not sufficient to identify Jeju black cattle from other relatives. We performed two times of successive multiplex PCR to provide a more accurate result for the identification of Jeju black cattle. The results suggest that two types of successive multiplex PCR methods using MC1R gene and Microsatellite derived primer set will be more useful to identification of Jeju black cattle, Hanwoo and imported beef.