• Journal of Life Science
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• v.9 no.5
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• pp.564-569
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• 1999

This study was conducted to determine the concentrations of plant growth regulators required for regeneration and the concentrations of antibiotics for the selection of transformed regenerants from lettuce, musk melon and tomato. The optimal concentrations of plant growth regulators for shoot formation were NAA 0.1 mg/$\ell$ +BA 0.1 mg/$\ell$ for lettuce, NAA 0.01 mg/$\ell$ +BA 2.0 mg/$\ell$ for melon and NAA 0.1 mg/$\ell$ +BA 0.5 mg/$\ell$for musk melon. Shoot induction from tomato, lettuce and melon was completely inhibited by 30 mg/$\ell$ or higher concentrations of kanamycin. Shoot formation from mu나 melon was not affected by kanamycin up to 40 mg/$\ell$, but was reduced in the presence of 50 mg/$\ell$ and completely inhibited by 100 mg/$\ell$. Shoot formation of all four crops was completely inhibited by higromycin at 10 mg/$\ell$. Both carbenicillin and cefatoxinme did not show any negative effects on shoot formation.

• Journal of Oral Medicine and Pain
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• v.32 no.2
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• pp.137-150
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• 2007

Trees emit phytoncide into atmosphere to protect them from predation. Phytoncide from different trees has its own unique fragrance that is referred to as forest bath. Phytoncide, which is essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Porphyromonas gingivalis, which is one of the most important causative agents of periodontitis and halitosis. P. gingivalis 2561 was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its cell viability, antibiotic sensitivity, morphology, and biochemical/molecular biological pattern. The results were as follows: 1. The phytoncide appeared to have a strong antibacterial effect on P. gingivalis. MIC of phytoncide for the bacterium was determined to be 0.008%. The antibacterial effect was attributed to bactericidal activity against P. gingivalis. It almost completely suppressed the bacterial cell viability (>99.9%) at the concentration of 0.01%, which is the MBC for the bacterium. 2. The phytoncide failed to enhance the bacterial susceptibility to ampicillin, cefotaxime, penicillin, and tetracycline but did increase the susceptibility to amoxicillin. 3. Numbers of electron dense granules, ghost cell, and vesicles increased with increasing concentration of the phytoncide, 4. RT-PCR analysis revealed that expression of superoxide dismutase was increased in the bacterium incubated with the phytoncide. 5. No distinct difference in protein profile between the bacterium incubated with or without the phytoncide was observed as determined by SDS-PAGE and immunoblot. Overall results suggest that the phytoncide is a strong antibacterial agent that has a bactericidal action against P. gingivalis. The phytoncide does not seem to affect much the profile of the major outer membrane proteins but interferes with antioxidant activity of the bacterium. Along with this, yet unknown mechanism may cause changes in cell morphology and eventually cell death.