• Korean Journal of Plant Tissue Culture
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• v.21 no.1
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• pp.7-14
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• 1994

Immature zygotic embryos of five Korean soybean cultivars cultured on Murashige and Skoog's (MS) medium supplemented with various concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) produced somatic embryos without forming an intervening callus. The highest frequency (up to 90%) of somatic embryo formation was obtained when zygotic embryos were cultlued on medium containing 1 to 2 mga 2, 0-D in four cultivars. However the frequency was highly variable to the cultivars. Transversely sliced primary somatic embryo halves were also capable of forming secondary embryos at frequencies of up to 70% when cultured on medium containing 0.1 to 1 mg/L 2,4-D. Somatic embryos formed on zygotic embryos cultured on medium containing 0.1 to 0.2 mg/L 2,4-D had two cotyledons more frequently than one horn-type cotyledon and those on medium containing 0.5 to 4mg/L 2,4-LD had a horm-type cotyledon at a prominently higher freequency. However somatic embryos on medium containing 10mg/L or higher concentrations of 2,4-D were usually shunted at the globular stage even after transfer to medium containing lower concentrations of 2,4-D or other growth regulators. non somatic embryos with one or two cotyledons or a hem-type cotyledon were transferred to medium containing $GA_3$, those with two cotyledons converted to plantlets at a higher frequency (25%) than the others.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.159-164
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• 2001

To produce novel bioactive flavonoids, Gericudranin A and Gericudranin B, a cell culture system of Cudrania tricuspidata including callus induction and optimization of culture conditions was established. Friable calli were efficiently induced from the hypocotyl segments of seedlings on B5 medium supplemented with 1.0 mg/L NAA, 0.1 mg/L kinetin and 3% sucrose. Several factors were optimized for the Gericudranin production and the cell growth in suspension cultures. Low level of basal salt medium (1/8 MS), 1.0 mg/L IAA and 0.1 mg/L zeatin, and high level of sucrose (5%) were effective for the production of Gericudranins, whereas WPM with 1.0 mg/L NAA, 0.1 mg/L zeatin, and 5% sucrose were more effective for the cell growth. When cells were cultured on MS liquid medium supplemented with 1.0 mg/L IBA, about 2200 $\mu\textrm{g}$/g dry wt of Gericudranin A could be produced. The level might be about 10 times of the native inner bark. About 2350 $\mu\textrm{g}$/g dry wt of Gericudranin B was also produced on MS liquid medium with 5% sucrose, 1.0 mg/L NAA, 0.1 mg/L kinetin. The content was estimated about 3 times of the level of native inner bark.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.856-863
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• 2013

Application of rhizospheric fungi is an effective and environmentally friendly method of improving plant growth and controlling many plant diseases. The current study was aimed to identify phytohormone-producing fungi from soil, to understand their roles in sesame plant growth, and to control Fusarium disease. Three predominant fungi (PNF1, PNF2, and PNF3) isolated from the rhizospheric soil of peanut plants were screened for their growth-promoting efficiency on sesame seedlings. Among these isolates, PNF2 significantly increased the shoot length and fresh weight of seedlings compared with controls. Analysis of the fungal culture filtrate showed a higher concentration of indole acetic acid in PNF2 than in the other isolates. PNF2 was identified as Penicillium sp. on the basis of phylogenetic analysis of ITS sequence similarity. The in vitro biocontrol activity of Penicillium sp. against Fusarium sp. was exhibited by a 49% inhibition of mycelial growth in a dual culture bioassay and by hyphal injuries as observed by scanning electron microscopy. In addition, greenhouse experiments revealed that Fusarium inhibited growth in sesame plants by damaging lipid membranes and reducing protein content. Co-cultivation with Penicillium sp. mitigated Fusarium-induced oxidative stress in sesame plants by limiting membrane lipid peroxidation, and by increasing the protein concentration, levels of antioxidants such as total polyphenols, and peroxidase and polyphenoloxidase activities. Thus, our findings suggest that Penicillium sp. is a potent plant growth-promoting fungus that has the ability to ameliorate damage caused by Fusarium infection in sesame cultivation.

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.161-170
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• 1989

The proteases of Toxoplasma gcndii were purified partially and characterisrd for some biochemical properties including various chromatographic patterns, major catalytic classes, and conditions to promote the activity of these enzymes. When Toxoplasma extract was incubated with 3H-casein at various pH, peak hydrolysis of casein was observed at pH 6.0 and at pH 8.5. Proteasfs working at pH 6.0 and at pH 8.5 were purified partially by conventional methods of chromatographies of DE52 anion rxchange, Sephadex G-200 gel permeation, and hydroxylapatite chromatography. Partially purified enzymes were tested by site-specific inhibitors and promotorf. The protease working at pH 6.0 was inactivated by iodoacetamide with LDso of 10-5 M and promoted by dithiothreitol, while the protease working at pH 8.5 was inhibited by phenylmethylsulfonyl fluoride with LD50 of 10-5 M and was Promoted by ATP (excess ATP beyond 2 mM inhibited the activity reversely). The protease of pH 8.5 had the activity of ATPase which might exert the energy to its action. Therefore the former was referred to as a cysteinyl acid protease and the latter, ATP-dependent neutral serine protease.

• Korean Journal of Medicinal Crop Science
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• v.5 no.1
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• pp.49-55
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• 1997

This study was conducted to establish mass propagation system from the tissue culture using immature embryos in Eleutherococcus senticosus. Immature embryos from seeds were removed under the microscope and placed on MS, $MSB_5\;and\;B_5$ medium containing several plant growth regulators. While the calli were well formed on media containing 2 mg/l of 2, 4-D, 2 mg/l of 2, 4-D and 0.7 mg/l of TDZ, shoot regeneration was better on MS medium with combinations of high concentrations of TDZ and low concentrations of 2, 4-D. Treatment of 2, 4-D alone was better than treatment of TDZ alone in callus induction, but plant regeneration was reversed. The results of callus formation and shoot regeneration on $MSB_5\;and\;B_5$ media were similar to those of MS media. The rate of callus formation was nearly 100% when 2, 4-D was added to $B_5$, medium on concentration of 2 mg/l or 0.7 mg/l. TDZ showed very significant effect on the formation of multiple shoots.

• Korean Journal of Medicinal Crop Science
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• v.5 no.1
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• pp.21-27
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• 1997

This experiments were conducted to determine the effect of thidiazuron on forming tuberlets and plant regeneration of Pinellia ternata T. by tissue culture. The addition of $5\;{\mu}M$ TDZ to the medium had better regeneration than that of any other treatments of NAA and TDZ. At the combination treatments of NAA and TDZ, as the level of thidiazuron increased, the rate of shoot regeneration was incresed while the increment of NAA concentration inhibited the rate of shoot regeneration. The supplement of $5\;{\mu}M$ thidiazuron produced the best number of micro-tubers per explant and the number of micro-tuber formed was 25 in MS medium and 29 in MG medium on 30 day culture, respectively. Microtuber formation was the best on MG medium with 1.0 mg/l NAA and $5\;{\mu}M$ thidiazuron. MG medium was superior to MS and B5 medium for the growth of tuberlets. Half strength of MS medium with NAA 2 mg/l was the most effective for root formation. Rooting ability on nursery soil of plantlets produced in in vjtro was good as a 80% after 3 weeks.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.371-379
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• 2001

The objective of this study was to establish an effective cryopreservation method of in vitro-produced bovine embryos. For the vitrification, in virtro-produced embryos at 8-cell, morula and blastocyst stages were exposed to freezing solution containing 5.5 M EG (EG 5.5) for 20 sec, loaded on each containers such as EM grid, OPS and Cryo-loop, and then immediately plunged into liquid nitrogen at -196$^{\circ}C$. Thawed embryos were serially diluted in 0.5, 0.25 and 0.125 M sucrose in m-HPBS, each for 1 min, and cultured in CRlaa medium supplemented with 10% FBS. Significant differences in the rates of re-expanded and hatched embryos were not observed among these embryo containers. The total cell number of expanded blastocyst cultured in vitro after vitrification was examined by Hoechst staining. There were no differences between non-vitrified (180.0 $\pm$ 5.4) and vitrified groups (178.0 $\pm$ 7.5). In addition, when the cellular injuries after vitrification were compared by double staining. There were no significant difference in the ratio of live and dead cells between non-vitrified group (176 : 4) and vitrified group (172 : 6). Therefore, these results suggest that bovine embryos can be cryopreserved easily, effectively and successfully by vitrification using various containers, such as EM grid, OPS or Cryo-loop in the presence of EG 5.5 freezing solution.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.368-373
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• 2010

Juniperus chinensis var. sargentii Henry is a short and creeping evergreen shrub which reaches about 60 cm in height and only occurs in the northeast Asia and in the top of high mountains over the Korea. The Korea Forest Service protects it strictly by law since J. chinensis var. sargentii is an eccentric plant and possibly may be exterminated soon in Korea. This study was carried out to develop the propagation technique by cutting for conservation of genetic resources of J. chinensis var. sargentii. The rooting responses of branch cuttings, obtained from hard(May) and semi-hard wood shoots (August) to four growth regulators, namely, IAA, IBA, NAA and Rooton(exceptionally powder method) applied at various concentrations(0, 100, 200, 500, 1000 and 2000 $mgL^{-1}$) were examined in mixed soil media. Rooting rate showed significant difference between cutting times, among kinds and among concentrations of growth regulators. The optimum cutting time was April to May in hardwood cutting. The application of IBA 1000 $mgL^{-1}$(rooting rate : 36.4%) was most effective in callus formation and rooting of cutting. Relatively, rooting of cutting of the control taken in May was 30.4%. Root characteristics such as number, length and diameter of root were not significantly affected by kinds and concentrations of growth regulators in hardwood cutting.

• Journal of Plant Biology
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• v.35 no.1
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• pp.9-15
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• 1992

The plantlet was regenerated on MS medium containing BAP (2 mg/I) and 1M (1 mg/I) from leaf discs of pepper after 3 weeks of culture. And then, we investigated the activity of peroxidase and esterase and the pattern of their isozymes from leaf, stem and root in order to observe physiological and biochemical changes on the developemental stage, respectively. The peroxidase was expressed with tissue specificity because peroxidase activity according to the developemental stage of the tissue was not only highest in the leaf of the pepper at 10 days after it germinated but also 2 new bands of its isozyme were found in pI 7.2 and pI 5.2. However, a new pI 3.4 band was found in the leaf and root of the pepper after 14 days of germination, and in the stem was found out pI 5.2 band. As regeneration of leaf dises was progressed, its peroxiase activity was increased about 80% more than that of control after 14 days of culture and new pI 3.2 and 6.5 bands of it isozyme were found. The results suggested that peroxidase would be connected with regeneration of pepper. Also, esterase activity was increased about 50% more than that of control after 14 days of culture, the pattern of esterase isozyme was shown to be 3 cathodic bands and 1 anodic band after 7 days of culture.ulture.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.127-132
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• 1999

Protoplasts were isolated from the leaf mesophyll tissue of in vitro 4-weeks-old Arabidopsis thaliana and cultured in MS liquid medium supplemented with 2.0 mg/L NAA, 0.5 mg/L BAP and 9% mannitol in the dark at $25^{\circ}C$. When protoplast-derived microcolonies were dehydrated, the frequency of callus induction enhanced approximately 7-fold higher compared with non-dehydrated microcolonies in CP medium. Fifty callus lines were selected from dehydrated microcolonies. Shoots were efficiently initiated from the green spots of the selected shoot forming calli cultured on MS regeneration medium supplemented with 0.05 mg/L IAA, 7.0 mg/L 2-iP and 30 g/L sucrose under continous illumination for 4 weeks. Shoot regeneration frequencies (calli regenerating at least one shoot) were 3.5%~56%. Histological observations of shoot forming callus revealed that tracheary elements initiated from inner compact cells, and that meristemoids developed to shoot primordia and shoots. Roots were induced from these regenerating shoots on MS medium without phytohormones. These regenerants were successfully transplanted into potting soil. Morphological characterization of 50 protoplast-derived plants showed that the frequency of normal type was 78%.