• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.05a
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• pp.17-17
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• 2010

Ethylene, known as a stress hormone regulate wide developmental processes including germination, root hair initiation, root and shoot primordial formation and elongation, leaf and flower senescence and abscission, fruit ripening. The acceleration of ethylene biosynthesis in plant associated with environmental and biological stresses. 1-Aminocycloprophane-1-carboxlyate deaminase(ACCD) is an enzyme that cleaves ACC into and ammonia, a precursor of the plant hormone ethylene. Plant growth-promoting rhizobacteria (PGPR) having ACCD can decrease endogenous ACC level of tissue, resulting in reduced production of ethylene in plants. ACC deaminse was a key enzyme for protect stressed plants from injurious effects of ethylene. ACCD gene was encoded from Pseudomonas flourescens, PGPR and was cloned in Escherichia coli. We expressed the recombinant ACCD(rACCD) containing 357 amino acids with molecular weight 39 kDa that revealed by SDS-PAGE and western blot. The rACCD was purified by Ni-NTA purification system. The active form of rACCD having enzyme activity converted ACC to a-ketobutyrate. The optimal pH for ACC deaminase activity was pH 8.5, but no activity below pH 7.0 and a less severe tapering activity at base condition resulting in loss of activity at over pH 11. The optimal temperature of the enzyme was $30^{\circ}$ and a slightly less severe tapering activity at 15 - 30$^{\circ}$, but no activity over $35^{\circ}$. P. flourescens ACC deaminase has a highly conserved residue that plays in allowing substrate accessibility to the active sites. The enzymatic properties of this rACCD will provide an important reference for analysis of newly isolated ACCD and identification of newly isolated PGPR containing ACCD.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.304-304
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• 2017

In semi-arid countries such as Namibia, the flooding unexpectedly happens in a rainy season, causing losses in the yield of upland-adapted cereal crop. In flooding conditions, rice roots sequentially form aerenchyma and a barrier to radial oxygen loss (ROL), and oxygen is released into the rhizosphere near the root tips. Iijima et al. (2016) and Awala et al. (2016) reported that close mixed-planting with rice can mitigate the flood stress of co-growing upland-adapted cereal crop by modifying their rhizosphere microenvironments via the oxygen released from the rice roots. Moreover, by using the model system of hydroponic culture, it was confirmed that oxygen from rice roots was transferred to co-growing upland-adapted cereal crop in close mixed planting system (Kawato et al., 2016). However, it is not sure whether the ability of oxygen release varies among rice cultivars, because Kawato et al. (2016) used only one japonica cultivar, Nipponbare (Oryza sativa). The objective of this study was to compare the ability of oxygen release in rhizosphere among rice cultivars. The experiment was conducted in a climate chamber in Kindai University. We used 10 rice cultivars from three different rice species (O. sativa (var. japonica (2), var. indica (3)), Oryza glaberrima Steud. (2) and their interspecific progenies (3)) to compare the ability of oxygen release from the roots. According to the method by Kawato et al. (2016), the dissolved oxygen concentration of phase I (with shoot) and phase II (without shoot) were measured by a fiber optic oxygen-sensing probe. The oxygen released from rice roots was calculated from the difference of the measurements between phase I and phase II. The result in this study indicated that all of the rice cultivars released oxygen from their roots, and the amount of released oxygen was significantly correlated with the above-ground biomass (r = 0.710). The ability of oxygen release (the amount of the oxygen release per fresh root weight) of indica cultivars (O. sativa) tended to be higher as compared with the other cultivars. On the other hand, that of African rice (O. glaberrima) and the interspecific progenies tended to be lower. These results suggested that the ability of oxygen release widely varies among rice cultivars, and some of indica cultivars (O. sativa) may be suitable for close mixed-planting to mitigate flood stress of upland-adapted cereal crop.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.397-403
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• 2012

The vitality of immature tooth could be lost by dental caries, trauma and fracture of malformed tooth. The vitality loss might lead to halt of the development of the root. The recommended endodontic treatment for a non-vital immature permanent tooth is apexification. Apexification is a method of inducing apical closure through the formation of mineralized tissue in the apical pulp region. Calcium hydroxide is the material of choice for apexification. Long-term exposure to calcium hydroxide may form the apical hard tissue, but weaken the dentin due to its alkaline nature and thus make the roots more susceptible to fracture. It is important to preserve any weakened tooth, so a permanent restoration is needed to reinforce teeth that are prone to fracture. The purpose of this case report was to describe the treatment for reinforcing immature teeth treated with long-term calcium hydroxide. In these cases, the apexes of teeth were sealed with MTA plugs and the root canals were restored with composite resin and fiber post.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.134-141
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• 1991

In order to investigate the changes and characteristics of biochemical metabolic substances of soybean tissue culture during the cultural period, immature cotyledons were detached form the plant on 15th days after flowering and cultured in vitro for 3 weeks. The cultures were classified into embryogenic(EC) and non-embryogenic callus(NEC). A part of the EC lines were subcultured for another 3 weeks and classified into root forming(RFC), and shoot forming cultures(SFC). Another part of the EC lines were used for isolation of protoplasts, which were subsequently cultured in vitro for 4 weeks. The cultures were classified into embryogenic(PEC) and non-embryogenic callus(PNEC) derived from the protoplasts. The cultures of EC and PEC lines showed higher phenylalanine content and lower methionine content than those of NEC and PNEC. At organ differentiation stage, both cultures showed the content of aspartic acid decreased, while the other amino acids increased as a whole. The protein pattern analysis of the cultures revealed that EC and NEC lines contained distinctive polypeptides, with mass of ca. 18KD for EC and ca. 22KD for NEC respectively. The EC and PEC lines also showed high activity of peroxidase isozyme A(piA), while the RFC and SFC lines showed that of peroxidase isozyme B(piB).

• Restorative Dentistry and Endodontics
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• v.36 no.5
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• pp.377-384
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• 2011

Objectives: The purpose of this study was to observe the change in the viscoelastic properties of thermoplasticized injectable root canal filling materials as a function of temperature and to compare the handling characteristics of these materials. Materials and Methods: Three commercial gutta perchas and Resilon (Pentron Clinical Technologies) in a pellet form were heated in the Obtura-II system (Obtura Spartan) at $140^{\circ}C$ and $200^{\circ}C$, and the extrusion temperature of the thermoplasticized materials was measured. The viscoelastic properties of the materials as a function of temperature were evaluated using a rheometer. The elastic modulus G', viscous modulus G", loss tangent tan${\delta}$, and complex viscosity ${\eta}^*$ were determined. The phase transition temperature was determined by both the rheometer and a differential scanning calorimeter (DSC). The consistency of the materials was compared under compacting pressure at $60^{\circ}C$ and $40^{\circ}C$ by a squeeze test. Results: The three gutta perchas had dissimilar profiles in viscoelastic properties with varying temperature. The phase transition of softened materials into solidification occurred at $40^{\circ}C$ to $50^{\circ}C$, and the onset temperatures obtained by a rheometer and a DSC were similar to each other. The onset temperature of phase transition and the consistency upon compaction pressure were different among the materials (p < 0.05). Resilon had a rheologically similar pattern to the gutta perchas, and was featured between high and low-flow gutta perchas. Conclusions: The rheological characteristics of the thermoplasticized root canal filling materials changed under a cooling process. The dissimilar viscoelastic properties among the materials require different handling characteristics during an injecting and compacting procedure.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.791-796
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• 2003

Polyphenol oxidase isoforms were purified from the lotus roots using 50% acetone precipitation, conventional chromatographies of Q-Sepharose and hydrophobic interaction, and high performance liquid chromatographies of Mono-Q and Superdex 75 gel-filtration. Molecular mass of a purified PPO isoform (LPIII-2) was determined to be 56 kDa using gel-filtration chromatography. The active form of LPIII-2 appeared to bea heterodimer, as purified LPIII-2 on SDS-PAGE gel showed two bands that were determined to be 28 kDa and 26 kDa. To further characterize PPO, partially purified PPO isoforms (LP-II, LP-III) were obtained from Q-Sepharose anion-exchange chromatography. In substrate specificity, the partially purified PPO isoform LP-II showed a high affinity to catechol, while LP-III showed a high affinity to pyrogallol. The optimum pH of LP-II and LP-III was pH 7.0. Interestingly, the partially purified PPO isoforms showed high activities at low temperatures $(0{\sim}5^{\circ}C)$, and as temperatures rose, the activities decreased. Both PPO isoforms were stable at $40^{\circ}C$ and were inactivated by incubation at $60^{\circ}C$ for 40 min.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.1
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• pp.101-117
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• 1999

Amyotrophic lateral sclerosis (ALS) is a degenerative neuromuscular disease of unknown etiology in which the upper and lower motor neurons are progressively destroyed. Recent evidences support the role of autoimmune mechanisms in the pathogenesis of ALS. This study investigated the effects of sera from ALS patients on neuromuscular transmission in phrenic nerve-hemidiaphragm preparations and on calcium currents of single isolated dorsal root ganglion (DRG) cells in mice. Mice were injected with either control sera from healthy adults or ALS sera from 18 patients with ALS of sporadic form, for three days. Miniature end plate potential (MEPP) and nerve-evoked end plate potential (EPP) were measured using intracellular recording technique and the quantal content was determined. Single isolated DRG cells were voltage-clamped with the whole-cell configuration and membrane currents were recorded. Sera from 14 of 18 ALS patients caused a significant increase in MEPP frequency in normal Ringer's solution $(4.62{\pm}0.14\;Hz)$ compared with the control $(2.18{\pm}0.15\;Hz).$ In a high $Mg^{2+}/low\;Ca^{2+}$ solution, sera from 13 of 18 ALS patients caused a significant increase in MEPP frequency, from $2.18{\pm}0.31$ Hz to $6.09{\pm}0.38$ Hz. Sera from 11 of 18 patients produced a significant increase of nerve-evoked EPP amplitude, from $0.92{\pm}0.05$ mV to $1.30{\pm}0.04$ mV, while the other seven ALS sera did not alter EPP amplitude. In the ALS group, EPP quantal content was also elevated by the sera of 14 patients (from $1.49{\pm}0.07$ to $2.35{\pm}0.07).$ MEPP frequency and amplitude in wobbler mouse were $4.03{\pm}0.53$ Hz and $1.37{\pm}0.18$ mV, respectively, which were significantly higher than those of wobbler controls (wobblers without the symptoms of wobbler). Sera from ALS patients significantly reduced HVA calcium currents of DRG cells to 42.7% at -10 mV. Furthermore, the inactivation curve shifted to more negative potentials with its half-inactivation potential changed by 6.98 mV. There were, however, significant changes neither in the reversal potential of $I_{Ca}$ nor in the I-V curve. From these results it was concluded that: 1) The serum factors of sporadic ALS patients increase neuromuscular transmission and can alter motor nerve terminal presynaptic function. This suggests that ALS serum factors may play an important role in the early stage of ALS, and 2) Calcium currents in DRG cells were reduced and rapidly inactivated by ALS sera, suggesting that in these cells, ALS serum factors may exert interaction with the calcium channel.

• Korean Journal of Environment and Ecology
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• v.20 no.4
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• pp.425-435
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• 2006

The objectives of this research were to investigate the drought resistance as well as the growth of Wisteria floribunda seedlings with the soil water conditions. The seedlings for the research were grown in pots with strict water content control on a frame located outdoors. During the experiments, the soil water contents were adjusted to 5, 10, 20, 30, 40, 50, 60, and 70%. In addition, the effects of Rhizobium inoculation on the growth of seedlings were investigated. The experimental results are summarized as follows: 1. The seedlings in the pots with 5% soil water content withered to death due to the water stress. Withering or any distinct growth was not observed from the seedlings in the 10% soil water content. It can be inferred from these results that about 5% of soil water content is the wilting point of W. floribunda seedlings and about 10% is the critical soil water content of its growth in this experiment soils. Therefore, it seems that W. floribunda possesses a good drought resistance. 2. From the analyses of the main growth parameters such as stem elongation, diameter growth, leaf area growth and total dry weight, it was found that the seedling growth can be improved with increasing soil water contents. The relation between each growth parameter(Y) and the soil water contents(W) was well described by a quadratic equation, $Y=a+bW+cW^2$. 3. In soil water contents higher than 20%, the seedling growth(Y) was remarkable along with-its extended growing period, and related to the growing period(D) by a quadratic equation, $Y=a+bD+cD^2$. 4. The artificial inoculation of Rhizobiun promoted the growth of Wisteria floribunda seedlings. 5. Rhizobium was found to be more readily inoculated and to form more root nodules compared to seedlings grown in higher soil water contents.

• Journal of Oral Medicine and Pain
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• v.36 no.3
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• pp.199-205
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• 2011

During root canal treatment, overinstrumentation with hand or mechanically driven files can perforate the mandibular canal, allowing the extrusion of endodontic sealers, dressing agents, and irrigant solutions out of the tooth and into the canal. The patient may report symptoms such as pain, hyperesthesia, hypoesthesia, anesthesia, dysesthesia and paresthesia. Such problems must be resolved as quickly as possible to avoid irreversible sequelae caused by certain neurotoxic materials that form part of endodontic sealants. Although there have been no controlled trials of treatment protocols involving endodontically related injuries to the inferior alveolar nerve, the normal therapeutic sequence for this complication is the control of pain and inflammation and, whenever possible, the surgical elimination of the cause. However, total resolution of pain and reduction in or disappearance of paraesthesia after a non-surgical management have been reported. Antiepileptic drugs such as gabapentin or pregabalin have been used for the treatment of neuropathic pain. This article describes a case of inferior alveolar nerve(IAN) damage after endodontic treatment of a mandibular right second molar and the treatment with non-surgical approach using prednisone and gabapentin medication, monitoring the patient's condition with clinical neurosensory examination and current perception threshold test(Neurometer).

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.131-132
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• 2003

Leaf discs and apical meristems were cultured in Murashige and Skoog (MS) medium supplemented with cytokinin and auxin at different concentrations. Callus production was observed in all tested media after six days of incubation. Callus produced in the presence of high concentration of NAA (2.0mg/1) was fragile in texture and yellow in colour. Highest callus formation was observed from leaf discs in the medium supplemented with 1.0mg/1 NAA and 0.5 mg/l BAP in dark at $25{\pm}1{\circ}C$. Percentage of callus formation was 95% and mean callus fresh weight was 654.88 43.53 mg. Shoots were induced from the callus after 4 weeks in 1/2MS medium supplemented with BAP and kinetin both at 0.5mg/1. When elongated shoots were separated and transferred into multiplication medium (MS+0.5mg/1 BAP+0.5mg/1 kinetin) multiplication rate was 6.4 after 6 weeks. Higher concentrations of BAP caused callus production at the base. Direct shoot induction was observed from apical meristems in MS medium in the presence of 0.175 mg/1 IAA + 2.25mg/1 BAP and 0.175 mg/1 IAA + 3.0 mg/1 BAP in 16 hour day at $25{\pm}1{\circ}C$. Explants (apical meristems) elongated to form a single shoot forming a callus at the base. Adventitious buds were sprouted out from the base. Percentage explants which producing shoots was 28.57 and 65.5 respectively. Multiple shoot induction was also observed in the same media. Highest multiple shoot production was observed in the presence of 0.175 mg/l IAA and 3.0mg/l BAP, Mean number of shoots per explant was 5.36 and the mean shoot length was $16.66{\pm}4.15$mm. Shoots (20 30m length) were tested for root induction. Excised shoots were transferred into rooting media, which contains different concentrations of NAA and IAA. Best rooting performance was observed in 1/2MS medium supplemented with 0.1mg/1 NAA after 10 days of incubation in 16 hr photoperiod at $25{\pm}1{\circ}C$. Mean number of roots per shoot was 6 and the mean root length was 252mm. Rooted plantlets were transferred into sterile coir dust:sand (1:4) mixture and maintained in a humid chamber for two weeks, They were gradually exposed to the natural environment. After three weeks they were transferred to pots containing coir dust:sand (1:2) mixture for further development where the 90% survival was observed.