• Plant Biotechnology Reports
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• v.5 no.3
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• pp.225-234
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• 2011

Arabidopsis mutants with T-DNA insertion in seven calmodulin genes (CAM) were used to determine the specific role of CAM in the tolerance of plants to oxidative stress induced by paraquat and hydrogen peroxide ($H_2O_2$) treatments. Arabidopsis calmodulin mutants (cam) were screened for seedling growth, seed germination, induced oxidative damage, and levels of ${\gamma}$-aminobutyric acid (GABA) shunt metabolites. Only the cam5-4 and cam6-1 mutants exhibited an increased sensitivity to paraquat and $H_2O_2$ during seed germination and seedling growth. In response to treatments with $3{\mu}M$ paraquat and 1 mM $H_2O_2$, only the cam5-4, cam6-1 mutants showed significant changes in malonaldehyde (MDA) levels in root and shoot tissues, with highly increased levels of MDA. In terms of the GABA shunt metabolites, GABA was significantly elevated in root and shoot tissues in response to the paraquat treatments in comparison to alanine and glutamate, while the levels of all shunt metabolites increased in root tissue but not in the shoot tissue following the $H_2O_2$ treatments. GABA, alanine and glutamate levels were significantly increased in root and shoot of the cam1, cam4, cam5-4, and cam6-1 mutants in response to paraquat (0.5, 1 and $3{\mu}M$), while they were increased only in the root tissue of the cam1, cam4, cam5-4, and cam6-1 mutants in response to $H_2O_2$ (200 and $500{\mu}M$, 1 mM). These data show that the cam5-4 and cam6-1 mutants were sensitive to the induced oxidative stress treatments in terms of seed germination, seedling growth, and oxidative damage. The accumulation of GABA shunt metabolites as a consequence of the induced oxidative stress treatments (paraquat and $H_2O_2$ treatments) suggests that the GABA shunt pathway and the accumulation of GABA metabolites may contribute in antioxidant machinery associated with reactive oxygen species and in the acquisition of tolerance in response to induced oxidative stress in Arabidopsis seedlings.

• Earthquakes and Structures
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• v.23 no.3
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• pp.259-269
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• 2022

In this study, we introduce a canonical correlation analysis method to accurately assess the tunnel damage potential of ground motion. The proposed method can retain information relating to the initial variables. A total of 100 ground motion records are used as seismic inputs to analyze the dynamic response of three different profiles of tunnels under deep and shallow burial conditions. Nine commonly used ground motion parameters were selected to form the canonical variables of ground motion parameters (GMP_CCA). Five structural dynamic response parameters were selected to form canonical variables of structural dynamic response parameters (DRP_CCA). Canonical correlation analysis is used to maximize the correlation coefficients between GMP_CCA and DRP_CCA to obtain multivariate ground motion parameters that can be used to comprehensively assess the tunnel damage potential. The results indicate that the multivariate ground motion parameters used in this study exhibit good stability, making them suitable for evaluating the tunnel damage potential induced by ground motion. Among the nine selected ground motion parameters, peck ground acceleration (PGA), peck ground velocity (PGV), root-mean-square acceleration (RMSA), and spectral acceleration (Sa) have the highest contribution rates to GMP_CCA and DRP_CCA and the highest importance in assessing the tunnel damage potential. In contrast to univariate ground motion parameters, multivariate ground motion parameters exhibit a higher correlation with tunnel dynamic response parameters and enable accurate assessment of tunnel damage potential.

• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.709-716
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• 2008

Purpose: Autogenous transplantation of teeth can be defined as transplantation of teeth from one site to another in the same individual, involving transfer of impacted or erupted teeth into extraction sites or surgically prepared sockets". Successful autogenous transplantation of teeth depends upon a complex variety of factors. Such factors include damage to the periodontal ligament of the donor tooth, residual bone height of the recipient site, extra-oral time of tooth during surgery. Schwartz and Andreasen previously reported that autogenous transplantation of teeth with incomplete root formation demonstrated higher success rate than that of teeth with complete root formation. Gault and Mejare yielded similar rate of successful autogenous transplantation both in teeth with complete root formation and in teeth with incomplete root formation when appropriate cases were selected. This case report was aimed at the clinical and radiographic view in autogenous transplantation of teeth with complete root formation. Materials and Methods: Patients who presented to the department of periodontics, Chonnam National University Hospital underwent autogenous transplantation of teeth. One patient had vertical root fracture in a upper right second molar and upper left third molar was transplanted. And another patient who needed orthodontic treatment had residual root due to caries on upper right first premolar. Upper right premolar was extracted and lower right second premolar was transplanted. Six months later, orthodontic force was applied. Results: 7 months or 11/2 year later, each patient had clinically shallow pocket depth and normal tooth mobility. Root resorption and bone loss were not observed in radiograph and function was maintained successfully. Conclusion: Autogenous transplantation is considered as a predictive procedure when it is performed for the appropriate indication and when maintenance is achieved through regular radiographic taking and follow-up.

• Korean Journal of Plant Resources
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• v.12 no.1
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• pp.1-9
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• 1999

The experiments were carried out to determine the optimum conditions for the induction of hairy roots in ginseng(Panax ginseng C.A. Meyer) by Agrobacterium spp. We were examined the antibiotics resistance of Agrobacterium spp and various ginseng parts, and the media for induction of hairy roots. The optimum concentration of NaOCl for sterilization of ginseng root segments without tissue damage with reduce of contamination was 7% NaOCl for 15-20 min and 9% NaOCl for 5 min, respectively. The more ginseng ages, the more contamination of ginseng root segment by sterilized in 7% NaOCl for 20 min, and especially in ginseng root segments with epidermis in six-year old roots. The growth of Agrobacterium spp were inhibited, but ginseng root segments was death in 30mg/L tetracycline. In 500mg/L cefotaxime or 500mg/L carbenicillin, the growth of Agrobacterium sup were inhibited, and root segments was grown normally. The optimum conditions for induction of hairy roots were using the root segments of three-year old ginseng cultured in 1/2MS medium supplemented with 500mg/L cefotaxime, and inoculation of Agrobacterium to root segments were better co-culture than smear method. After 2 weeks co-culture, the callus induced in cambium of root segments cultured in 1/2MS solid medium with 500mg/L cefotaxime. And then after 2 weeks, ginseng hairy roots were induced in callus of root segments. PCR analysis of rot C gene fragment confirmed that hairy roots were transgenic tissues.

• Journal of Ginseng Research
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• v.38 no.2
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• pp.136-145
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• 2014

Background: This study aimed to develop a biocontrol system for ginseng root rot caused by Fusarium cf. incarnatum. Methods: In total, 392 bacteria isolated from ginseng roots and various soils were screened for their antifungal activity against the fungal pathogen, and a bacterial isolate (B2-5) was selected as a promising candidate for the biocontrol because of the strong antagonistic activity of the bacterial cell suspension and culture filtrate against pathogen. Results: The bacterial isolate B2-5 displayed an enhanced inhibitory activity against the pathogen mycelial growth with a temperature increase to $25^{\circ}C$, produced no pectinase (related to root rotting) an no critical rot symptoms at low [$10^6$ colony-forming units (CFU)/mL] and high ($10^8CFU/mL$) inoculum concentrations. In pot experiments, pretreatment with the bacterial isolate in the presumed optimal time for disease control reduced disease severity significantly with a higher control efficacy at an inoculum concentration of $10^6CFU/mL$ than at $10^8CFU/mL$. The establishment and colonization ability of the bacterial isolates on the ginseng rhizosphere appeared to be higher when both the bacterial isolate and the pathogen were coinoculated than when the bacterial isolate was inoculated alone, suggesting its target-oriented biocontrol activity against the pathogen. Scanning electron microscopy showed that the pathogen hyphae were twisted and shriveled by the bacterial treatment, which may be a symptom of direct damage by antifungal substances. Conclusion: All of these results suggest that the bacterial isolate has good potential as a microbial agent for the biocontrol of the ginseng root rot caused by F. cf. incarnatum.

• Journal of Life Science
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• v.10 no.4
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• pp.403-407
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• 2000

For the biological control of the root-lesion nematodes, Pratylenchus spp., which damage directly and indirectly to the leaf perilla, the nematical effect of three nematode-trapping fungi, Arthrobotrys oligospora, A. conoides and A. dactyloides was evaluated in the field. Three species of Arthrobotrys were isolated from the culture soil of leaf perilla in 1998 and were observed the capture of the root-lesion nematodes, Pratylenchus spp. by adhesive hyphal networks or constricting rings on agar. At 40 days after treatment, the plant-parasitic nematodes and root-lesion nematode populations were approximately increased 3.5 fold in untreated control plot, while the nematode population in fungi treatment plots was similar to initial population. In the A. dactyloides plot, however, the population of plant-parasitic nematodes and Pratylenchus spp. was approximately reduced 65% and 53%, respectively. Thus, the fungus A. dachyloides should provide as biological agent for the control of Pratylenchus spp.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.177-185
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• 1994

Slow seedling growth rate and nodulation failure of white clover (Trifolium repens L.) has been limited its good establishment to pastures. The experiment was done to determine the effect of removal of cotyledon and unifoliolate on the shoot, root growth, and nodule formation of 4 white clover cultivars for 8 weeks after the treatment. Four white clover cv. Regal (large leaf), Louisiana S-I (medium-large leaf), Grasslands Huia (mediumsmall leaf), and Aberystwyth S184 (small leaf), were grown in IOcm plastic pot containing 2:l:l soi1:sand:peat moss mixture until grown to cotyledon or unifoliolate stage and then removed one (Cl) or two cotyledons (C2) at cotyledon stage, and unifoliolate only (U), unifoliolate and one cotyledon (UCl) or unifoliolate and two cotyledons (UC2) at the unifoliolate stage, and the plants were sampled at 4, 6 and 8 weeks after the treatments. The intact plants had greater shoot and root dry weights, and no. of nodules than removal-treated ones. Removal treatments at cotyledon stage, the dry weight and no. of nodules more decreased in C1 and C2 than that of unifoliolate stage. While the severer cotyledon removal, the more reduction. Although the dry weights and no. of nodules steadily inclined with regrowing period, the former were higher in Regal and La. S-1 than in the others since 6 weeks after removal treatment but the latter was more in S 184 than in the others 8 weeks after removal treatment. Relationship between no. of nodules and shoot or root dry weight was analysed as linear mode while the earlier and severe removal, the steeper slope. It was concluded that severer damage of cotyledon and unifoliolate had detrimental effects on the shoot and root growth, nodule formation, and aftermath establishment of white clover.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.441-445
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• 2015

Carrot (Dacus carota var. sativus) is one of the top-ten most economically important vegetable crops produced worldwide, and the root-knot nematodes, Meloidogyne spp., are one of the most important pests in the carrot. In Korea, M. hapla and M. incognita are presumed to be the major root-knot nematodes distributing mostly in open carrot fields and greenhouses, respectively. In our study, currently-developed and commercial carrot cultivars and the parental lines were examined for their pathological responses to M. incognita and M. hapla 7 weeks after inoculation with about 1,000 second-stage juveniles (J2) of the nematodes. All the carrot cultivars and lines showed susceptible responses to both nematodes with the gall index (GI) of 2.4-4.4, which were always higher on the carrot plants infected with M. incognita than M. hapla. Gall sizes were remarkably larger with more serious reduction of the root growths in the plants infected with M. incognita than M. hapla, suggesting the carrot lines examined in our study were more susceptible to the former than the latter. In the infection sites of the root tissues, giant cells were more extensively formed, occupying larger stellar regions with the prominent destruction of adjacent xylem vessels by M. incognita than M. hapla. All of these results suggest M. incognita affect more seriously on the carrot plants that are grown in greenhouses, compared to M. hapla that has a major distribution in open carrot fields, which would be used for determining cropping systems based on target nematode species, their damage and pathological characteristics.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.221-221
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• 2022

Chromosome breakage occurred by DNA methylation inhibitor. Zebularine is known as DNA methylation inhibitor and suitable for water solubility among different DNA methylation inhibitors as 5-Azacytidine and 5-aza-2'-deoxycytidine. We used zebularine as mutagen according to different methods by roots absorption and seed imbibition. After zebularine treatment, DNA methylation inhibitor, we observed mitotic chromosome behavior what is different according to two different treatment methods. First, seed imbibition treatment in 1,000 μM of zebularine solution for 72 hours in dark conditions. The second treatment to seedlings of Keumkang was also treated in 1,000 μM of zebularine solution for 72 hours after germination. Root and shoot showed different elongations in each treatment. Root absorption treatment(3.01±0.48, 2.00±0.26) showed the shortest elongation in root and shoot than control(8.16±0.61, 4.03±0.48) and seed imbibition treatment(4.33±0.80, 2.48±0.36). It can be explained root tip meristematic cell activity was damaged by DNA methylation inhibitor. Primary root tips were collected in DW for 24 hours at low temperature(0℃) and fixed in fixation solution for 3 days to chromosome observation in mitosis. Mitotic index, chromosome structure and chromosome aberration were observed by phase-contrast microscope. Mitotic index of the control(0.29) showed twice mitotic cells as the treated groups(imbibition 0.15, absorption 0.14). Observation of chromosomes showed some short chromosomes and loosen chromosomes affected by zebularine. It is considered because of zebularine damage DNA in mitosis. We observed "gap by chromosome breakage" in chromosomes that have loose parts between centromere and telomere. It seems demethylation of zebularine occurs chromosome breakage.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.396-407
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• 2023

The golden apple snail (Pomacea canaliculata) has been utilized as a natural and eco-friendly control of weeds in rice paddy fields. However, P. canaliculata can damage other crops. In this study, the effectiveness of plant extracts from various natural sources that are reportedly effective against pests in the control of P. canaliculata was investigated. The four plant extracts were effective against P. canaliculata and ranked in descending order as green tea seed (Camellia sinensis) > root of red spider lily (Lycoris radiata) > leaves of tobacco (Nicotiana tabacum) > root of sophora (Sophora flavescens). The mortality rate of P. canaliculata was increased using 200 to 2000 mg/kg of green tea seed powder. However, shrubby sophora root extract did not significantly increase the mortality rate. The LC₅₀ and LC₉₀ of green tea seed, tobacco leaves, shrubby sophora root, and red spider lily root were 900 and 2800 mg/L, 956 and 2320 mg/L, 2162 and 5325 mg/L, and 512 and 1054 mg/kg, respectively. The LC₅₀ and LC₉₀ of ground powder of C. sinensis, N. tabacum, S. flavescens and L. radiata were 248 and 646 mg/L, 403 and 733 mg/L, 409 and 905 mg/L, and 493 and 1141 mg/L, respectively. The findings indicate the remarkable control potency of green tea seeds against the golden apple snail. An organic material incorporating the four plant powders may help control green apple snail in an ecosystem-friendly manner.