• Imaging Science in Dentistry
• /
• v.34 no.3
• /
• pp.137-144
• /
• 2004

Purpose: To investigate the effects of low dose irradiation on the calcium content and calcific nodule formation of the MC3T3-El osteoblastic cell line. Materials and Methods: Cells were irradiated with a single dose of 0.2, 0.4 and 0.6 Gy at a dose rate of 5.38 Gy/min using Cs-137 irradiator. After irradiation, the calcium content and calcific nodule formation were examined on the 1st, 2nd, 3rd and 4th week. Results: We did not find any significant difference of total calcium content after irradiation of 0.2, 0.4 and 0.6 Gy when compared with the unirradiated control group. There was no significant difference of total calcium content between 0.2, 0.4 and 0.6 Gy irradiated groups. We found an increased tendency of the calcific nodule formation after irradiation of 0.2, 0.4 and 0.6 Gy when compared with the unirradiated control group without significant difference of calcific nodule formation between 0.2, 0.4 and 0.6 Gy irradiated groups. Conclusion : The results showed an increased tendency of the calcific nodule formation after low dose irradiation. However, this tendency did not increase with the increase of irradiation dose.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.4
• /
• pp.531-537
• /
• 2006

Lactic acid-producing bacteria (LABs) are known to have various beneficial properties for health. However, they are generally considered to have an adverse effect on teeth, since they produce acid. Nonetheless, milk and cheese containing specific LAB strains were recently found to have an inhibitory effect on dental caries in children, with an inhibitory activity towards the growth of Streptococcus mutans suggested as the responsible mechanism. Accordingly, the current study selected a probiotic candidate for oral health and studied its inhibitory mechanism against dental caries. Twenty-two LAB species belonging to eleven genuses were screened for promoting bone nodule formation using direct microscopic examination. Only one isolate, Weissella kimchii strain PL9001, increased the bone nodule formation significantly. The addition of W. kimchii strain PL9001 to bone cells prepared from mouse calvaria increased the bone nodule formation, calcium accumulation, and activity of alkaline phosphatase (the osteoblastic marker). Moreover, W. kimchii strain PL9001 inhibited the invasion of Streptococcus mutans into bone cells, and an organic extract of the culture supernatant of W. kimchii strain PL9001 inhibited the growth of Strep. mutans. Therefore, the results suggest that W. kimchii strain PL9001 can be used as a preventive measure against dental caries. This is the first time that a LAB has been shown to promote bone nodule formation and prevent the invasion of Strep. mutans into bone cells.

• Journal of Plant Biology
• /
• v.16 no.3_4
• /
• pp.35-39
• /
• 1973

This investigation was conducted to study the effect of soybean mosaic virus (SMV) on various parameters of nodule formation at different stage of soybean plants. Differences in nodule formation were marked between soybean varieties tested, but nodules were small within soybean varieties infected with SMV. SMV-infection on soybeans were greatly reduced the number, size and weight of nodules, and the earlier the infection of SMV, the greater the reduction of nodules. Maximum reduction(83%) of nodules observed when "Kumkang-Daerip" soybeans were inoculated 2 weeks after seeding, but none occurred 8 weeks or later. Prominent decreases in number of nodules often resulted in an increase in nodu'e sizes in SMV-infected soybean plants.an plants.

• Journal of Korea Foundry Society
• /
• v.23 no.4
• /
• pp.187-194
• /
• 2003

The effect of rare earth elements (R.E)(from 0.0 to 0.04%) on the microstructure formation and mechanical properties of thin-wall ductile iron castings were investigated. Tensile strength and hardness were decreased with an addition of up to 0.03% rare-earth elements. After addition of more than 0.03%, those were increased. Graphite nodule sizes were the finest, nodule count was the highst regardless of thickness and volume fraction of ferrite was the largest when that was 0.02%. However, the nodule count was decreased with increasing R.E. Futhermore. nodule size increased with increasing thickness and the volume fraction of ferrite decreased as that was increased. Nodularity was increased regardless of the thickness as that was increased. The castings of minium thickness up to 3 mm was possible without the formation of chill.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.24 no.2
• /
• pp.75-81
• /
• 1979

15 soybean cultivars were tested with the sandculture to investigate the affinity of cultivars to the nodule bacteria, Rhyzobium Japonicum #23, and the effects of inoculation on the vegetative growth of cultivars. The amount of nodule formation until the flowering stage was significantly different among the cultivars. The cultivar Haman showed the best nodule formation of 122.2 nodules per plant, while the cultivar Busuk showed the least amount of nodule formation. The inoculation of the nodule bacteria resulted in an increased plant growth and especially the chlorophyll content was significantly improved by inoculation of the nodule bacteria.

• Imaging Science in Dentistry
• /
• v.35 no.1
• /
• pp.1-8
• /
• 2005

Purpose : To investigate the effects of irradiation on the calcium content and calcific nodule formation in the MC3T3-E1 osteoblastic cell line. Materials and Methods : Cells were irradiated with a single dose of 2,4 and 8 Gy at a dose rate of 5.38 Gy/min using a Cs-137 irradiator. After irradiation, the calcium content and calcific nodule formation were examined on the 1 st, 2nd, 3rd and 4th week. Results : A decreasing dose-dependent tendency of the cell proliferation rate was found in all irradiated groups of this experiment when compared with the unirradiated control group. In accordance with the duration of culture, there was no significant difference in the cell proliferation rate after irradiation of 2 Gy when compared with the unirradiated group, however a decreasing tendency was found in 4 Gy- and 8 Gy-irradiated groups. While an increase in total calcium content after irradiation of 2 Gy was found at week 1, week 2, and week 4, there was a decrease in calcium content at week 1 through 4 in the 8 Gy- irradiated group. Calcific nodule formation was increased in irradiated experimental groups when compared with the unirradiated control group in the 2 Gy-irradiated group, but decreased in the 4 Gy- and 8 Gy-irradiated groups at the same stage. Conclusion : The results showed a mild increasing tendency of the calcific nodule formation after irradiation of 2 Gy. However, a decreased calcific nodule formation in 4 Gy- and 8 Gy-irradiated groups was found. Taken together, the irradiation of 2 Gy mildly activated bone formation, however 4 Gy or 8 Gy suppressed bone formation by decreasing cell numbers in the MC3T3-El osteoblastic cell line.

• The Plant Pathology Journal
• /
• v.15 no.2
• /
• pp.127-130
• /
• 1999

Cytological changes of cowpea root at the early stage of root nodule formation (within 5 days after inoculation) were viewed by light and electron microscopy. The root region affected by the rhizobial infection, which was composed of a redial array of cortical cells, had prominent cell divisions, mostly anticlinal in the inner cortical cells and in addition oblique and periclinal in the outer cells. An infected root hair cell (or root hair-producing epidermal cell) had numerous infection threads and degenerated cytoplasm. Module meristem was formed adjacent to the infected root hair cell, and characterized by dense cytoplasm, prominent nucleus, numerous small vacuoles, and increased plastids, containing infection threads as well. Bacterial cells were dividing inside the infection thread, the wall materials of which appeared to be dissolved ad accumulated in small vacuoles. inner cortical cells contiguous to the nodule meristem appeared to be actively dividing and dedifferentiating; however, they were not infected by the rhizobia. These structural characteristics are similar to those in the Bradyrhizobium-soybean association previously reported, and may reflect the similar cytological process in cowpea in the early nodule formation.

• Journal of Korea Foundry Society
• /
• v.19 no.1
• /
• pp.84-90
• /
• 1999

In this study, CV cast iron was reverse transformed to produce harder second phase surrounding graphite nodules, and then the microstructure and related mechanical properties of the reverse transformed CV cast iron were investigated by using optical microscopy and by carrying out hardness, tension and impact test. The formation of hard second phase surrounding graphite nodules increased the hardness in CV cast iron. The marked increase in hardness was resulted from the formation of martensite surrounding graphite nodule. It is expected from these results that the formation of martensite surrounding graphite nodule would improve the wear resistance of CV cast iron. The formation of both martensite and pearlite surrounding graphite nodule improved the tensile properties. Impact properties were decreased with increasing the volume fraction of hard second phase. However, the reduced impact properties could be recovered through phase transformation of martensite into pearlite and sorbite by tempering.

• Molecules and Cells
• /
• v.40 no.1
• /
• pp.17-23
• /
• 2017

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors.

• Journal of Korean Society of Forest Science
• /
• v.101 no.3
• /
• pp.443-453
• /
• 2012

The objectives of this study were to find out proper potting medium and nutrient levels in the soil to promote the root nodule formation in black locust (Robinia pseudoacacia L.) seedlings. Commercial potting medium, compost, organic fertilizer, molded forest fertilizer, and compound fertilizer were used at different mixing rates to bring in various levels of mineral nutrients in the soil. Seedlings were grown in pots in a greenhouse for three months. Commercial potting medium containing peatmoss, vermiculite, and geolite was not suited for early nodule formation due to lack of nutrients, even though it produced good total dry weight. Compost was the best medium to promote both high total dry weight production and nodule formation with providing the proper levels of nitrogen and phosphorus in the soil. Molded forest fertilizer was acceptable for nodule formation. Compound fertilizer and organic fertilizer was not suited for nodule formation. The potting medium should contain optimum levels of nitrogen (0.05-0.2%) and phosphorus (100-600ppm) to promote early nodule formation in black locust seedlings.