Yoon Jeong Lee

Decursin from Angelica gigas Nakai Inhibits B16F10 Melanoma Growth Through Induction of Apoptosis.

Decursin, a bioactive phytochemical isolated from Angelica gigas Nakai (danggwi), has shown preclinical anticancer efficacy in various cancer models. However, the antitumor effect of decursin in melanoma models remains undefined. The antitumor activities of decursin were investigated in B16F10 cells in vitro and in vivo. In this study, we show that treatment with decursin inhibited cell proliferation in a dose-dependent manner in B16F10 cells, but not in normal cells. Decursin also induced apoptosis in B16F10 cells, as determined by annexin V-staining assay and transferase-mediated nick-end labeling (TUNEL) staining assay. Decursin increased the phosphorylation of p38 as well as the expression of Bax while decreasing the phosphorylation of extracellular signaling-regulated kinase (ERK) and the expression of Bcl-2 in B16F10 cells. Moreover, decursin activated caspase-3 in B16F10 cells and xenograft tumor tissue. Together, these findings support further investigations into the potential use of decursin in the treatment of melanoma cells.

Failure to induce inhibition of cyclin A and up-regulation of p21 expression in phorbol ester-resistant U937 cells by phorbol ester

Differentiation resistant U937 cells were derived from parental U937 cells by selecting for continuously growing U937 cells in cell cultures continuously exposed to phorbol 12 myristate 13-acetate (PMA). Unlike in other known PMA resistant U937, the basal expression of protein kinase C (PKC) isozymes in these PMA resistant cells (R-U937) was significantly decreased. Subsequent analyses revealed differences between the wild type U937 and the R-U937 cells with respect to G1 phase arrest, which seemed to occur in U937 because of low levels of cdk2 kinase activity. This abolished cdk2 kinase activity is mainly due to inhibition of cdk2 phosphorylation, cyclin A down-regulation and cyclin dependent kinase inhibitor p21 up-regulation. Our data suggest that events down-stream of PKC activation may mediate cell cycle control. Thus, the R-U937 cells could be useful for further PKC mediated cell cycle control studies.

NK2-specific domain is responsible for cell death upon ectopic expression of VND in various Drosophila tissues

Drosophila ventral nervous system defective (VND) is a transcription factor containing tinman domain, homeodomain, and NK2-specific domain. The VND plays an essential role during the development of embryonic nervous system, however, little is known about its roles beyond embryonic stage. In this study, the expression patterns and levels of the VND during larval and adult stages were examined by using GAL4/UAS binary expression system and real-time PCR. The VND protein was expressed in larval brain, eye, and wing imaginal discs, implying possible roles of this protein in the larval tissues other than embryonic nervous system. Gain-of-function phenotypes of vnd were analyzed by crossing various GAL4 drivers with UAS-vnd transgenic line. Interestingly, we observed the massive cell death in the tissues including eye and wing discs where GAL4 is expressed. To down-regulate endogenous vnd transcripts in the eye disc, UAS-vnd-IR (inverted repeat) was crossed with ey3.5-GAL4 line. Loss-of-function phenotypes of vnd also revealed the black ommatidial spots indicating apoptotic cell death in the transgenic eye tissues. To identify a domain within the VND involved in apoptosis, VND mutant proteins were ectopically expressed in the eye disc. In contrast to VND-Δtinman and VND-Y54M mutant proteins, overexpression of VND-ΔNK2 did not lead to cell death, indicating that NK2-specific domain is responsible for apoptosis. Taken together, our results suggest that VND might be involved in the development of the various tissues after embryonic stages and in apoptosis via NK2-specific domain.

Changes of Contrast Sensitivity According to Light Transmittance of Color Lenses

This paper attempted to suggest the standards of light transmittance based on the analysis of the changes in contrast sensitivity of photopic condition according to the light transmittance of tinted lenses. The subjects of the experiment were 24 male and 13 female adults with normal ocular functions. They were asked to wear four tinted lenses (gray, brown, red, and green) in turn. The light transmittance of the lenses were 80~90%, 60~80%, 43~60%, and 30~43%, respectively. Contrast sensitivities were measured by using F.A.C.T. chart. The results showed that contrast sensitivities were decreased in proportion to the decrease of the light transmittance, and visual sensitivity of brown lenses were the highest and that of red lenses were the lowest. The results of the experiments suggested that the light transmittance should be over 38% for brown, gray and green lenses, and over 52% for red lenses. Accordingly the appropriate light transmittance should be considered when tinted lenses are selected for the purpose of eye protection in everyday life.

Complete mitochondrial genome of endangered Rhodeus pseudosericeus and its implications for the reconstruction of phylogenetic relationship among Acheilognathinae species

Abstract Rhodeus pseudosericeus is a native bitterling to the Korean Peninsula and found in very limited areas with small census size. Here, its complete mitochondrial genome was analyzed to provide novel data for the reconstruction of phylogenetic relationship among Acheilognathinae species. The genome was a 16,574 bp long consisting of 1 putative control region, 2 rRNA genes, 22 tRNA and 13 protein-coding genes. The gene arrangement was completely identical to those observed in other Acheilognathinae species as well as in other cyprinid species. In our phylogenetic analyses, three major genera of Acheilognathinae indepedently formed monophyletic groups in the tree reconstructed based on the whole genome sequences, whereas Rhodeus was not recovered as a single monophyly when solely considering protein-coding genes, indicating that the taxonomic reevaluation is still required in this subfamily.

Study of muscle contraction induced by electrical pulse stimulation and nitric oxide in C2C12 myotube cells

[Purpose] This study aimed to examine the independent effect of electrical pulse stimulation(EPS) and nitric oxide(NO) on muscle contraction and their synergistic or combined effect on contraction phenomenon using C2C12 mouse skeletal muscle cells. [Methods] Some differentiated C2C12 myotube cells were untreated (control). Other cells did not receive EPS and did receive 0.5, 1.0, or 2.0 mM of the NO donor, S-nitroso-N-acetyl-penicillamine (SNAP; -E/S0.5, -E/S1.0, and -E/S2.0, respectively). For the EPS treatments (0.3 V/mm, 1.0 Hz, and 4.0 ms), differentiated C2C12 myotube cells received only EPS or both EPS and the SNAPtreatments at the same concentrations (+E/-S, +E/S0.5, +E/S1.0, and +E/S2.0, respectively). All samples were then cultured for 4 days. [Results] Differentiated C2C12 cellswere stimulated by the EPS, NO, and EPS+NO treatments. The cell length of the +E/S2.0 Group after the 4-day culture (84.2±13.2㎛) was the shortest of all the groups. The expressions of AMPK, JNK, Akt, eNOS, GLUT4, and PGC1α proteins were noticeably dominant. The results indicated synergistic effect on muscle contraction of simultaneously applied EPS and SNAP. [Conclusion] Motor skills were significantly improved when exercise was accompanied by the intake of NO precursor and/or NO, compared to that upon their independent application or treatment.

Panax ginseng Leaf Extracts Exert Anti-Obesity Effects in High-Fat Diet-Induced Obese Rats

Recent studies have reported that the aerial parts of ginseng contain various saponins, which have anti-oxidative, anti-inflammatory, and anti-obesity properties similar to those of ginseng root. However, the leaf extracts of Korean ginseng have not yet been investigated. In this study, we demonstrate the anti-obesity effects of green leaf and dried leaf extracts (GL and DL, respectively) of ginseng in high-fat diet (HFD)-induced obese rats. The administration of GL and DL to HFD-induced obese rats significantly decreased body weight (by 96.5% and 96.7%, respectively), and epididymal and abdominal adipose tissue mass. Furthermore, DL inhibited the adipogenesis of 3T3-L1 adipocytes through regulation of the expression of key adipogenic regulators, such as peroxisome proliferator-activated receptor (PPAR)-γ and CCAAT/enhancer-binding protein (C/EBP)-α. In contrast, GL had little effect on the adipogenesis of 3T3-L1 adipocytes but greatly increased the protein expression of PPARγ compared with that in untreated cells. These results were not consistent with an anti-obesity effect in the animal model, which suggested that the anti-obesity effect of GL in vivo resulted from specific factors released by other organs, or from increased energy expenditure. To our knowledge, these findings are the first evidence for the anti-obesity effects of the leaf extracts of Korean ginseng in vivo.

Human-mediated processes affecting distribution and genetic structure of Squalidus multimaculatus, a freshwater cyprinid with small spatial range

ABSTRACT Endemic species typically have a narrow niche breadth, and are likely more vulnerable to extinction than more widespread taxa. Squalidus multimaculatus is a small cyprinid endemic to the Korean Peninsula, and its reported geographical range was restricted to several small rivers located along the southeast coast. Several populations of S. multimaculatus have supposedly been subject to a variety of recent anthropogenic actions. Here, we analyzed the pattern of genetic diversity within and among populations of S. multimaculatus using nine microsatellite loci to quantify the relative contributions of human-mediated processes to the contemporary distribution and genetic structure. Overall, low levels of genetic diversity were exhibited in the populations of S. multimaculatus. Genetic differentiations among populations were not completely represented by their geographical proximity, likely resulting from the low intrapopulation genetic variability and anthropogenic transplants. The most conspicuous outcome of the anthropogenic activities was the introgression of alleles from a closely related species, S. gracilis majimae. Our study showed that anthropogenic transplanting, even with only a small number of individuals, can challenge our conservation goal to maintain the species integrity that has long been shaped in evolutionary processes.

The Effect of Rutin on Antioxidant and Anti-inflammation in Streptozotocin-induced Diabetic Rats

The study examined the antioxidant activities and anti-inflammatory effects of rutin from the streptozotocin (STZ)-induced diabetic rats. Results revealed that the levels of plasma glucose and serum glucose were remarkably higher in the STZ-treated group compared to other groups and were significantly reduced in the STZ+rutin treated group compared to the STZ-treated group. In terms of weight, it significantly increased in all experimental groups during the experiment period except for STZ-induced diabetic group. The weight of the STZ-treated group was remarkably reduced compared to other groups. Regarding the weight of each body organ, the STZ-treated group showed higher organ weight compared to the other groups while STZ+rutin-treated group showed significantly reduced kidney and liver weights compared to those of STZ-treated group. In the pancreas tissue of the STZ-treated group, -cell destruction and vacuolization were observed. Inflammation in the heart, liver, kidney, and retina tissues were also vividly recorded. In the STZ+rutin administered group, the heart and retina tissues were shown to be preserved normally while the liver and kidney tissues showed reduced histopathology in general compared to the STZ-treated group. Conclusionally, the rutin has the effect on the antioxidant activities and anti-inflammation in the STZ-induced diabetic rats.

The genetic structure of Squalidus multimaculatus revealing the historical pattern of serial colonization on the tip of East Asian continent

Separated river systems could create confluences via two geological processes, estuary coalescence in response to decreasing sea levels and headwater capture, allowing primary freshwater species to disperse across rivers. Squalidus multimaculatus, is an endemic and primary freshwater species restricted to the southeast coast of the Korean Peninsula. The distribution of this species is unique, given that other congeneric species, including its closely related S. gracilis majimae, as well as other cyprind species are observed throughout the peninsula except for the east coast. Phylogeographic analyses were conducted using three mitochondrial loci to identify the origin of S. multimaculatus and the historical pathways of dispersal. A strong phylogenetic affinity between S. multimaculatus and S. g. majimae and the genetic structure among populations indicated that S. multimaculatus originated from the eastward colonization of the common ancestor between S. g. majimae and S. multimaculatus via headwater capture through fault zones within successive mountain range. Following colonization, the ancestral S. multimaculatus likely migrated towards north via estuary coalescence along a well-developed continental shelf. Our study was the first empirical attempt providing insights into how freshwater organisms dispersed to the southernmost tip of East Asia, despite the potential loss of such historical imprints with anthropogenic interference.