Tooth loss in elderly is mainly caused by alveolar bone loss via severe periodontitis. Although the severity of periodontitis is known to be affected by age, the aging process or the genetic changes during the aging of periodontal tissue cells are not well characterized. In this study, we investigated the effect of in vitro aging on the change of gene expression pattern in periodontal fibroblasts. Gingival fibroblasts (GF) and periodontal ligament fibroblasts (PDL) were obtained from two young patients and replicative senescence was induced by sequential subcultivation. When more than 90% cells were positively stained with senescence-associated β-galactosidase, those cells were regarded as aged cells. In aged GF and PDL, the level of phosphorylated retinoblastoma (RB) and p16INK4A protein was significantly decreased and increased, respectively. However, the protein level of p53 and p21, well known senescence-inducing genes, did not increase in aged GF and PDL. Although P27Kip1 and p15INK4B, another cyclin-dependent kinase inhibitors, were reported to be involved in replicative senescence of human cells, they were decreased in aged GF and PDL. Because senescent cells showed flattened and enlarged cell shape and are known to have increased focal adhesion, we examined the protein level of several integrins. Aged GF and PDL showed increased protein level of integrin α2, αu, and β1. When the gene expression profiles of actively proliferating young cells and aged cells were compared by cDNA microarray of 3,063 genes and were confirmed by reverse transcription-polymerase chain reaction, 7 genes and 15 genes were significantly and commonly increased and decreased, respectively, in aged GF and PDL. Among them, included are the genes that were known to be involved in the regulation of cell cycle, gene transcription, or integrin signaling. The change of gene expression pattern in GF and PDL was minimally similar to that of oral keratinocyte. These results suggest that p16INK4A/RB might be involved in replicative senescence of periodontal fibroblasts and the change of gene expression profile during aging process is cell type specific.

Calcium concentration in the bone resorption lacunae is high and is in the mM concentration range. Both osteoblast and osteoclast have calcium sensing receptor in the cell surface, suggesting the regulatory role of high extracellular calcium in bone metabolism. In vitro, high extracellular calcium stimulated osteoclastogenesis in coculture of mouse osteoblasts and bone marrow cells. Therefore we examined the genes that were commonly regulated by both high extracellular calcium and 1.25(OH)₂vitaminD₃(VD3) by using mouse oligo 11 K gene chip. In the presence of 10 mM [Ca²+]e or 10 nM VD3, mouse calvarial osteoblasts and bone marrow cells were co-cultured for 4 days when tartrate resistant acid phosphatase-positive multinucleated cells start to appear. Of 11,000 genes examined, the genes commonly regulated both by high extracellular calcium and by VD3 were as follows; 1) the expression of genes which were osteoclast differentiation markers or were associated with osteoclastogenesis were up-regulated both by high extracellular calcium and by VD3; trap, mmp9, car2, ctsk, ckb, atp6b2, tm7sf4, rab7, 2) several chemokine and chemokine receptor genes such as sdf1, scya2, scyb5, scya6, scya8, scya9, and ccr1 were up-regulated both by high extracellular calcium and by VD3, 3) the genes such as mmp1b, mmp3 and c3 which possibly stimulate bone resorption by osteoclast, were commonly up-regulated, 4) the gene such as c1q and msr2 which were related with macrophage function, were commonly down-regulated, 5) the genes which possibly stimulate osteoblast differentiation and/or mineralization of extracellular matrix, were commonly down-regulated; slc8a1, admr, plod2, lox, fosb, 6) the genes which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were commonly up-regulated; s100a4, npr3, mme, 7) the genes such as calponin 1 and tgfbi which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were up-regulated by high extracellular calcium but were down-regulated by VD3. These results suggest that in coculture condition, both high extracellular calcium and VD3 commonly induce osteoclastogenesis but suppress osteoblast differentiation/mineralization by regulating the expression of related genes.

Concerns remain regarding the biocompatibility and adverse effects of dental casting alloys. The aim of this study was to understand the cytopathogenic effect of metal ions, which might be released from dental alloys, on oral squamous carcinoma(OSC) cells. The cellular morphology, viability, the type of cell death and molecular change in response to metal ion salt solutions including aluminum(Al), cobalt(Co), copper(Cu) and nickel(Ni) were examined. The values for the metal ions with the exception of AI were estimated to be between 400 and 600μM. The cells treated with the metal ions showed apoptotic change with the exception of Al ions. Metal ion-induced apoptosis was further confirmed using flow cytometric analysis. This study showed that the cytotoxicity and the mode of cell death by metal ions clearly depend on the cell type, the type of metal ion and the duration of exposure. The protein level of Rb, a tumor suppressor that affects apoptosis para-doxically, was higher in the cells treated with Co, Cu and Ni. It is believed that apoptosis and cell damage in the OSC cells treated with Co, Cu or Ni can be evoked by the regulation of Rb.

A new white multi-flowering gladiolus with pale greenish core “Wind Ensemble” was released by the National Horticultural Research Institute (NHRI) in 2003. A cross was made between white multi-flowering cultivar “White Nova”, which was released at the NHRI in 2002 and white line “95-24 (True Love × Madame Valdiek)”. It was crossed in 1999 and finally selected in 2003 after investigation of the characteristics for 4 years from 2000 to 2003. “Wind Ensemble” has multiple middle sized florets. This cultivar is middle flowering without stem bending. It has good production of cormlets, vigorous growth and resistant to virus, Fusarium and thrips. The width of “Wind Ensemble” flower is 11.2 cm. The plant height is 130 cm. Days to flowering of “Wind Ensemble” is average 100days in summer season.

A new bright white gladiolus “White Lace” was released by the National Horticultural Research Institute (NHRI) in 2004. A cross was made between late flowering white cultivar “White Goddess” and vigorous white cultivar “Amsterdam”. It was crossed in 1999 and finally selected in 2004 after investigation of the characteristics for 5 years from 2000 to 2004. “White Lace” has a bright white color and multi-flowering florets more than 20 florets with good simultaneous flowering more than 8 florets. This cultivar is middle flowering without stem bending. It has good production of cormlets, vigorous growth and resistant to virus, Fusarium and Thrips. The width of “White Lace” flower is 11.5 cm. The plant height is 137cm. Days to flowering of “White Lace” is average 93days in summer season.

A new bright scarlet gladiolus “Adlib Scarlet” was released by the National Horticultural Research Institute (NHRI) in 2003. A cross was made between early flowering salmon line “94-18 (Arianne×Hongkwang)” and early flowering salmon cultivar “Adlib Salmon”, which was released at the NHRI in 2000. It was crossed in 1999 and finally selected in 2003 after investigation of the characteristics for 4 years from 2000 to 2003. “Adlib Scarlet” has a multiple middle sized bright scarlet florets with good simultaneous flowering. This cultivar is early flowering and moderately resistant against virus and neck rot. It has vigorous growth without stem bending. The width of “Adlib Scarlet” flower is 10.8 cm. The plant height is 132 cm. Days to flowering of “Adlib Scarlet” is average 92days in summer season.

“Surabyeo” is a new japonica rice cultivar developed from a backcrossed combination between the F1 of “Suweon 345/ Kanto PL4” and “Suweon 345” of lodging tolerant, semi-dwarf, high-quality rice line by the rice breeding team of National Crop Experiment St