Dentin is a mineralized tissue formed by odontoblasts that are differentiated from ectomesenchymal cells , The molecul ar mech anism of odontoblast diffe rentiation remains unclear, Amino acid transporters play an important role in s up plying nutri tion to normal a nd ca ncer cells including odntoblasts, and for cell proliferation , Amino acid transport system L is a maj or nutrient t ransport system responsible for the Na+' -independent transport o[ neutral amino acids incJuding several essentiaJ amino acids , The system L is divided into two major subgroups, the L-type amino acid transporter 1 (LAT1) and the L-type amino acid transporter 2 (LAT2) , In this study, the expression pattern and role of amino acid transport system L were, therefore, investigated in the differentiation of MDPC-23 cells derived from mouse dental papilla celJs , To determi ne the expression Jevel o[ amino acid transport system L participating in intracelJ ular transport of amino acids in the differentiat ion 0 1' MDPC-23 cells, it was examined by RT-PCR, observation of cell morphoJogy‘ A1izaline red-S staining ancl uptake analysis after inclucing experimental differentiation in MDPC-23 cells The res ults were as follows , The LAT1 mRNA was expressed in the early stage of MDPC-23 cell differentiation , The expression leveJ was gradually increased by time course and it was decreased after the late stage, The LAT2 mRNA was not observed in the earJy stage of MDPC-23 cell differentiation, The LAT2 mRNA was expressed at the 11 days 0 1' MDPC-23 cell differentiation and the expression level was gradually decreased by time course, There was no changes in the expression level of 4F2hc mRNA, the cofactor of LAT1 and LAT2, during the differentiation of MDPC-23 cells , The expression of ON mRNA was graduaJJy decreased but the expression of ALP mRNA was increased during differentiation of MDPC-23 cells , The L-Ieucine uptake was increased by time cour se from the early stage to the 9 days in MDPC-23 cell differentiation , The amount of L-Ieucine uptake was maintained to the 11 and 14 days of MDPC-23 cell differentiation As the resul ts‘ it is considered that among neutral amino acid transport system L in differentiation of MDPC-23 cells , the LATl has a key role in cell proliferation in the early stage and middle stage of cell differentiation and the LAT2 has an important roJe in ceJJ differenti ation and mineralization in the Jate stage of cell differentiation for providing cells with neutral a mino acids incJuding several essentiaJ amino acids

System L amino acid transporter is a major route for providing living cells with neutral amino acids including several essential amino acids. To elucidate the expression pattern of L-type amino acid transporter 1 (LAT1) in the bone formation process, the expressions of LAT1 and its subunit 4F2 heavy chain (4F2hc) were investigated in the healing process after the implantation of bone graft materials in the calvarial osseous defected rats. Circular calvarial defects (1 cm in diameter) were made midparietally. The rats were divided into 4 groups of 1 control group and 3 experimental groups. In the control group, the defect was only covered with soft tissue flap. In the experimental groups, they were filled with human particulate dentin (particulate dentin group), with plaster of Paris (plaster of Paris group) and with the mixture of human particulate dentin and plaster of Paris with ratio of 2 : 1 by weight (mixture group). The rats were sacrificed at the 1, 2, 4 and 8 weeks after operation and the RT-PCR analysis and immunohistochemical analysis were performed. In the RT-PCR analysis, the mRNAs of LAT1 and 4F2hc were strongly detected in all 4 groups. In the immunohistochemical analysis, at 1 week after operation, the LAT1 protein and its subunit 4F2hc protein were mainly expressed in the osteoblasts, osteocytes and interstitial tissues of the around the defect and inner part of newly forming bone in all 4 groups. The expressions of LAT1 and 4F2hc proteins were decreased at 2 and 4 weeks after operation. The LAT1 and 4F2hc proteins were scarcely expressed at 8 weeks after operation in all 4 groups. These results suggest that the LAT1 and its subunit 4F2hc highly expressed at the early stage of new bone formation and may have an important role in providing cells with neutral amino acids including several essential amino acids at that stage.

Amino acid transporters are essential for the growth and proliferation in all living cells. Among the amino acid transporters, the system L amino acid transporters are the major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The L-type amino acid transporter 1 (LAT1) is over-expressed to support cell growth in malignant tumors. The double stranded RNA-mediated RNA interference (RNAi) analysis can be in a wide variety of eukaryotes to induce the sequence-specific inhibition of gene expression. In this study, we examined the effect of LAT1 short interfering RNA (siRNA) on cell growth using siRNA of LAT1 in the KB human oral squamous cell carcinoma. In the RT-PCR analysis and western blot analysis, the siRNA of LAT1 inhibited expressions of LAT1 mRNA and protein. The uptake of [14C]L-leucine was inhibited by siRNA of LAT1. In the MTT assay, the siRNA of LAT1 inhibited the growth of the KB cells in the time-dependent manner, indicating that the growth inhibition of KB cell by the siRNA of LAT1 is induced by the blocking of neutral amino acid transport mediated by LAT1. These results suggest that the transport of neutral amino acids including several essential amino acids into the KB human oral squamous cell carcinoma is mediated mainly by LAT1. Further, the LAT1 would be a new target for the inhibition of cancer cell growth.

Amino acids a re required fo1' protein synthesis and energy sources in all living cell s. System L amino acid trans porters neutral amino aci cls i n a Na +' - independent manner. In ma 1ignan t tumors the L-type amino acid t ranspor te r 1(LA1'1), the first isoform 0 1' system L. is highly expressed to suppor t tumo1' cell growth. ln the present study, the expression 0 1' the system L amino acid transporter and BCH cytotoxicity were examined and compa red in both rat gli a l and C6 g lioma cel ls 1'he rat glia l cells expressed the L-type arnino acid t ra nsporter 2(LA1'2). the second isoform 이 system L, with its subu ni t 4F2hc. whereas the LA1'1 was not expressed. 1'he C6 glioma cells expressed LA1'1 with 4F2hc but not LA1'2 1'he [14C]L-leucine uptakes by the glial and C6 glioma cells were inhibi ted by BCH in a co ncent ration-d e pendant man ner wi th the lC50 values of 270.0 :t 13.7 μ M and 73.1 :t 4.5 μ M, respectively. 1'he cell g rowth was inh ibi ted by BCH in the time, concen tration-dependant manner in the gli al and C6 glioma cell s . 1'he rate of cell growth inhi bit ion induced by BCH in the C6 glioma cells was hi gh er than that in the gli al cells 1'hese results s uggesL that the tra ns ports of neutra l amino acids inc1uding several essenti al amino acids into rat g lial and C6 glioma cel ls a re for the most part mediated by LA1'2 and LA1'1, respectively. Therefore‘ the rat glia1 and C6 gJioma cells are excell ent tools for examing the proper ties of LA1'2 and LA1'1, respectively. Moreover, the spec너 i c inh ibi tion 0 1' LATl in cancel cells might be a new rationa le f'or anti -cancer therapy

Arrùno acid transpoπers play an important role in supplying nutrition to cells and for cell proliferation. System L is a major nutrient transport system responsible for the Na+-independent transport of large neutral amino acids including several essential amino acids. In malignant tumors, a system L transporter L-type amino acid transporter 1 (LATl) is upregulated to support tumor cell growth. In the present study, we have examined the expression and function of system L amino acid transporter in FaDu human pharyngeal squamous carcinoma cells. RT-PCR, real-time quantitative RT-PCR and westem blot analysis have revealed that the FaDu cells express LATl together with its associaω19 protem 4F2hc, whereas the FaDu cells do not express the other system L isoform L-type amino acid transporter 2 (LAT2). 까le uptake of L-(14Clleucine by FaDu cells is Na+-independent and almost completely inhibited by system L selective inhibitor 2-aminobicyclo-(2,2,1)-heptane-2- carboxylic acid (BCH). The profiles of the inhibition of L-[I4Cllellcine uptake by variolls amino acids in the FaDu cells are comparable with those for the LA T1 expressed in Xenopus 。()(찌es. π1e majority of L-[I4Clleucine uptake is, therefore, mediated by LAT1 in the FaDu cells. These results suggest that the transport of neutral amino acids including several essential amino acids in the FaDu human pharyngeal squamous carcinoma cells mediated by LAT1. In addition, specific inhibition of LAT1 by such agents as BCH in pharyngeal squamous cell carcinomas will be a new rationale for anti-cancer therapy.

Odontogenic keratocysts(OKCs) are frequently associated with erupted or impacted tooth. In such instances, the radiographic features simulate those of a dentigerous cyst. The purpose of this study was to evaluate a comparative immunohistochemical expression of Ki-67 as a proliferative marker and apoptotic signals in the OKC associated with or without impacted tooth. In addition, we have also been investigated with regard to the proliferative activity and apoptosis comparing the unilocular and multilocular varieties of the OKC. The material for this study consisted of thirty-two cases of OKCs (OKC with impacted tooth, n=16；OKC without impacted tooth, n=16) and ten cases of dentigerous cysts as a comparison. The results revealed that the proliferative activity and apoptosis of OKCs with impacted tooth was higher than those of dentigerous cysts. However, there was no correlation between Ki-67 immunoreactivity or apoptosis and association with or without impacted tooth in 32 cases of OKCs. In addition, this present study showed that there was no correlation between the unilocular and multilocular varieties of the OKCs in proliferative activity and apoptosis.

It has been said that amino acid transporters play an important role in supplying nutrition to normal and cancer cells and for cell proliferation. System L is a major nutrient transport system responsible for the Na+-independent transport of large neutral amino acids including several essential amino acids. In malignant tumors, a system L transporter L-type amino acid transporter 1(LAT1) is up-regulated to support tumor cell growth. In the present study, we have examined the function of LAT1 and its expression in the KB human oral epidermoid carcinoma cells. RT-PCR, western blot analysis and immunohistochemical analysis have revealed that KB cells express LAT1 in the plasma membrane together with its associating protein 4F2hc, whereas KB cells do not express the other system L isoform LAT2. The uptake of L-[14C]leucine by KB cells is Na+-independent and almost completely inhibited by system L selective inhibitor BCH. The profiles of the inhibition of L-[14C]leucine uptake by amino acids in the KB cells are comparable with those for the LAT1 expressed in Xenopus oocytes. The majority of L-[14C]leucine uptake is, therefore, mediated by LAT1 in the KB cells. These results suggest that the uptakes of neutral amino acids including several essential amino acids in the KB oral epidermoid carcinoma cells mediated by LAT1. In addition, specific inhibition of LAT1 by such agents as BCH in human oral squamous cell carcinomas will be a new rationale for anti-cancer therapy.

In this study, the concentrations of isoflavones, anthocyanins and total phenol content (TPC) in 19 soybean mutant lines changed seed coat color from yellow to black or brown were determined. Among 19 soybean mutant lines, 5 soybean mutant lines with black pigment were detected 3 anthocyanins (delphinidin-3-O-β-D-glucoside, D3G; cyaniding 3-O-β -D-glucoside, C3G; petunidin 3-O-β-D-glucoside, Pt3G). The highest concentration of anthocyanins among 5 soybean mutant lines was D-16 (1280.0 ± 19.4 mg/100g seed coat) derived from cv. Danbaek. Although isoflavone contents of all soybean mutant lines showed lower levels compared to original cultivars, glycitein was detected only 5 soybean mutant lines (DP-37-2, DP-38, DP-39, DP-40, and DP-41 derived from cv. Daepung). In TPC of 19 soybean mutant lines, DP-10 was increase levels compared to original cultivar, while DP-37-2, DP-40, and DP-41 were decrease levels of TPC. Using reduction of DPPH, we measured the free radical scavenging activity (FRSA) among 19 soybean mutant lines. Five black and 4 brown soybean mutants showed significant increase in FRSA. On the basis of these results, it was concluded that gamma irradiation may change the isoflavone, anthocyanin, and total phenol contents of soybean. These mutant lines using in this study can be useful for the breeding of soybean varieties altering the nutritional values.

To determine the expression levels of genes related to the salt stress response in rice, gene expression profiles were investigated through microarray analysis using the rice mutant line Till-II-877. There were no significant changes in physiological response under salt stress of the mutant increased less than that in the WT. The intensity of gene expression was analyzed and compared between the wild type and mutant lines using a microarray. Among the most significantly affected pathways, α-linolenic acid metabolism and linoleic acid metabolism (in lipid metabolism), fructose and mannose metabolism and glycolysis-gluconeogenesis (in carbohydrate metabolism), cysteine and methionine metabolism (in amino acid metabolism), and carbon fixation (in the energy metabolism of photosynthetic organisms) showed changes in gene expression levels under salt stress. These results further our understanding of the effects of salt stress in rice and may aid in the development of salt-tolerant rice cultivars.

Soluble sugar content in soybean seed is an important quality attribute for soyfood and feed. Usually, soluble sugars comprise 6 to 17% of total dry wt. in mature soybean seeds. In this study, 414 soybean mutant lines induced by gamma-ray were screened by colormetric assay, FACE (Fluorophore-assisted carbohydrate electrophoresis), and GC-MS to identify the change of soluble sugar contents. Among 414 soybean mutant lines, 12 mutant lines derived from three different soybean cultivars (Hwanggum, Paldal, and Bangsa) showed higher level of soluble sugar content compared to their original cultivars. However, 5 mutant lines derived from soybean landrace KAS 636-15 showed lower level in the colormetric assay. In FACE, 17 soybean mutant lines selected by colormetric assay also showed different band intensity compared with their original cultivars. However, there were no different soluble sugar patterns between soybean original cultivars and mutant lines. Finally, the variations of soluble sugar content in 17 soybean mutant lines were confirmed by using GC-MS. These mutant lines will be used for genetic study to find mutations of genes related soluble sugar biosynthesis.

A new poinsettia cultivar 'Scarlet' was bred by the National Horticultural Research Institute (NHRI) in 2006. A cross was made between 'Christmas Eve', a variety with dark green leaves and dark red bracts, and 'Red Velvet', a red colored variety in 2003. 'Scarlet' was finally selected in 2006 after investigating the growth and flower characteristics from 2004 to 2006. 'Scarlet' has bright red colored and elliptic bracts and has absent or very weak intensity of rugosity between veins in bract. In comparison with the check variety, 'Red Velvet', plant height is tall, leafblade is long and narrow. Petiole is also longer than that of 'Red Velvet'. Short day response is fast and its bracts are fully colored 7 weeks after short day commencement.

A new poinsettia cultivar 'Miss Maple' was bred by the National Horticultural Research Institute (NHRI) in 2006. A cross was made between 'Sonora Red', a variety with short plant height, dark green leaves and dark red bracts, and 'Cranberry Punch', a deep pink colored variety in 2003. 'Miss Maple' was finally selected in 2006 after investigating the growth and flower characteristics from 2004 to 2006. 'Miss Maple' has light red colored and obovate bracts, and has weak intensity of rugosity between veins in bract. Fully colored transitional leaves are so deeply lobed that they resemble the leaves of maple. Plant height is shorter than that of 'Cranberry Punch', the check variety. Short day response fast and its bracts are fully colored 7 weeks after short day commencement.

A new soybean variety “Geomjeongkong 3” was released by the National Crop Experiment Station, RDA, in 2001. This variety was derived from the cross between Shinano-kuro and SNU78010, the elite breeding line with large seed, in the summer season, 1990. The