• Applied Biological Chemistry
• /
• v.43 no.4
• /
• pp.231-235
• /
• 2000

The changes of calmodulin levels, calmodulin-binding proteins, and $Ca^{2+}$/calmodulin-dependent glutamate decarboxylase during the growth of tobacco suspension cells were investigated. Tobacco cells exhibited a typical growth curve, including an exponential growth phase between 3 and 5 days after inoculation, and an apparent stationary phase occurring after 5 day. Although slight changes were observed from sample to sample, calmodulin protein levels remained similar during the phases of culture growth. Several $Ca^{2+}-dependent$ calmodulin-binding proteins including 56, 46, 36, and 32-kDa proteins were detected in tobacco cell extracts. The 56-kDa protein was identified as glutamate decarboxylase by Western-blot analysis using an anti-GAD monoclonal antibody. The levels of GAD protein and the specific activity of GAD enzyme were highest during the middle exponential phase of the culture growth cycle. These data suggest that $Ca^{2+}$/calmodulin-dependent glutamate decarboxylase is modulated during the growth of tobacco suspension cells.

• The Plant Pathology Journal
• /
• v.32 no.3
• /
• pp.228-241
• /
• 2016

In our previous study, we reported that a novel endophytic bacterium Bacillus oryzicola YC7007 has suppressed bacterial diseases of rice via induced systemic resistance and antibiotic production. This endophytic strain, B. oryzicola YC7007 was used as a biological control agent against bakanae disease of rice caused by Fusarium fujikuroi, and its mechanism of interaction with the pathogen and the rice was further elucidated. Root drenching with B. oryzicola YC7007 suspension reduced the disease severity of bakanae significantly when compared with the untreated controls. The treatments of B. oryzicola YC7007 suspension ($2.0{\times}10^7cfu/ml$) to the rice rhizosphere reduced bakanae severity by 46-78% in pots and nursery box tests containing autoclaved and non-autoclaved soils. Moreover, in the detached rice leaves bioassay, the development of necrotic lesion and mycelial expansion of F. fujikuroi were inhibited significantly by spraying the culture filtrate of B. oryzicola YC7007. Drenching of ethyl acetate extracts of the culture filtrate to the rhizosphere of rice seedlings also reduced the bakanae disease severity in the plant culture dish tests. With the root drenching of B. oryzicola YC7007 suspension, the accumulation of hydrogen peroxide was observed at an early stage of rice seedlings, and a hormonal defense was elicited with and without pathogen inoculation. Our results showed that the strain B. oryzicola YC7007 had a good biocontrol activity against the bakanae disease of rice by direct inhibition, and was also capable of inducing systemic resistance against the pathogen via primed induction of the jasmonic acid pathway.

• Korean Journal of Plant Tissue Culture
• /
• v.22 no.3
• /
• pp.143-148
• /
• 1995

The competence of callus formation and plant regeneration from root derived callus was higher in japonica cultivars than those of Tongil-type cultivars of rice. A japonica type cultivars Yeongdeogbyeo, showed the highest capacity (13%) for plant regeneration from root calli of 6 cultivars tested. The callus induced from seed and root tissues maintained higher capacity for plant regeneration during 7 passages of subculture on N$_{6}$ solid media at 2-week intervals. The maximum frequency (2 x 10$^{5}$ mL) of round cells and their cell colonies showed about 24 days after suspension culture of root-derived callus in N$_{6}$ medium with lmg/L 2,4-D, 300mg/L casein hydrolysate, 10mM L-proline, 20g/L sucrose and 30g/L sorbitol. The frequency of somatic embryo formation in suspension cultures of root-derived callus increased with prolonged advance of subculture time from 30 to 90 days, but their regenerative capacities decreased.

• Korean Journal of Plant Tissue Culture
• /
• v.22 no.2
• /
• pp.111-114
• /
• 1995

To produce ${\gamma}$-linolenic acid (GLA) by cell cultures of Lithospermum erythrorhizon, we optimized medium compositions including carbon sources, nitrogen sources and growth regulators. MS basal medium supplemented with 1.0 mg/L 2, 4-D was effective for callus induction from mesophyll tissue. Addition of sucrose at 88mM concentration induced active proliferation of suspension cells and increased GLA content. Increased supplement of potassium nitrate as nitrogen source resulted in proliferous cell growth and increased total fatty acid content Abscisic acid increased cell growth and fatty acid content in callus culture, whereas as it had an inhibitory effect in suspension cell culture.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.5
• /
• pp.396-401
• /
• 2006

The objective of this study was to investigate the antitumor activity of suspension cultures of tea callus cells grown in the presence of different concentrations of the growth regulator 2,4-dichlorophenoxy acetic acid (2,4-D) with or without light irradiation. The methanol and ethanol extracts of precipitated cells (MEP, EEP) exhibited stronger inhibitory effects on the growth of tumor cell lines than the water extract of precipitated cells (WEP) or the supernatant Compared to culture under dark conditions, exposure to light irradiation led to significantly higher antitumor activity. The MEP from light irradiated cells at $250{\mu}g/mL$ with 2.0mg/L 2,4-D displayed more than 64% growth inhibition of HEP-2 cells, whereas normal cells showed less than 25% growth inhibition. The some fractions of MEP obtained from Diaion HP-20 column chromatography displayed the majority of inhibitory activity against the HEP-2 cell line. These results show that 2,4-D, and light stimulated the synthesis of antitumor compounds.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.3
• /
• pp.306-316
• /
• 1997

Embryogenic calli were induced from mature seed scutella of anther culture-derived rice variety Zhonghua 8. Cell suspension cultures were initiated from friable embryogenic calli and utilized as source material for protoplast isolation. Generally, the older and finer cell suspensions gave higher protoplast yields than younger suspension cultures. Protoplasts exhibited sustained cell division and formed microcalli when cultured in KPR medium supplemented with 0.5 mg $l^{-1}$ 2,4-D, 1.0 mg $l^{-1}$ NAA and 0.5 mg $l^{-1}$ zeatin using the agarose embedding procedure without feeder cells. Protoplast plating efficiencies ranged from 0.20 to 0.54％. Microcalli were transferred to MS medium supplemented with 2.0 mg $l^{-1}$ kinetin and 0.5mg $l^{-1}$ NAA for plant regeneration. The regeneration frequencies were 2 to 12％, depending on the cell suspension lines of Zhonghua 8. The plants were transferred to the glasshouse and were fertile.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.13 no.1
• /
• pp.1-6
• /
• 1993

This experiment was conducted to select acid tolerant cells from red clover suspension culture and obtained following results. The most effective condition of plant growth regulators for suspension culture of red clover cells was 2 mg/l 2,4-D as auxin source plus 0.5 mg/l BAP as cytokinin source. Among serveral basal media, PC medium brought the best result. The most suitable EMS concentration for the mutated cells tolerant to acid was 1 % with fours treatment and average 27 colonies/plate were selected. The frequency of the occurence of mutants tolerant to acid in 1 % EMS with four hours treatment was 8.9 $\times$ 10$^{-5}$ which was 100 times larger than that of control. The total colonies selected initially were 176 but the survived colonies after two subcultures with 4 weeks interval in a selection medium were 44.

• Korean Journal of Medicinal Crop Science
• /
• v.2 no.1
• /
• pp.44-50
• /
• 1994

This study was carried out to select the appropriate medium(especially, carbon and nitrogen source ) for somatic embryogenesis in order to develop the rapid mass production system in suspension culture of chuanxiang Hort. Suitable medium for somatic embryo formation was MS medium. The half strength MS medium was effective for somatic embryo development. Sucrose was the most effective carbon source for somatic embryo formation, however, production of somatic embryos was reduced at higher concentration of sucrose. Effects of suger was the same as sucrose. Somatic embryo formation was higher as the decrease of $NH_{4}NO_3$, and optimum ratio of $KNO_3\;:\;NH_4NO_3$ was 825 : 238mg /1. Regenerated plant was obtained in MS basal medium and survival late of plantlet was 60-70% after transplanted directly to the vermiculite.

• Journal of Plant Biotechnology
• /
• v.47 no.3
• /
• pp.227-234
• /
• 2020

To produce the miraculin protein in suspension cultures, rice (Oryza sativa L.) was transformed with Agrobacterium tumefacience EHA105 containing the miraculin AB512278 gene. The cell suspension cultures were established using cell lines selected from transgenic rice callus. The integration of the miraculin gene into the rice chromosome was confirmed using genomic PCR analysis. In addition, RT-PCR analysis indicated that the miraculin gene is expressed in the selected suspension cell lines. Thus, the recombinant miraculin was expressed in the transgenic suspension cell line, HK-2. Therefore, we have successfully developed a HK-2 line that produces miraculin. These results demonstrate that transformed cell suspension cultures can be used to produce a taste-modifying protein such as miraculin.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.206-209
• /
• 2001

Recombinant human GM -CSF was expressed and secreted from transgenic rice cell suspension cultures in its biologically active form. This was accomplished by transforming rice callus tissues with an expression vector, pMYN44. containing the hGM -CSF cDNA. Regulated expression and secretion of hGM -CSF from this vector achieved using the promoter, signal peptide, and terminator from a rice alfa-amylase gene Amy3D. The Amy3D gene is expressed in response to sugar deprivation. The recombinant hGM -CSF was expressed from the transgenic rice cell culture on the sugar-free medium as a yield of about 110 mg/L in the culture filtrate, which was determined by ELISA. Biological activity of hGM-CSF was confirmed by measuring the proliferation of the hGM -CSF dependent TF -1 cells.(This work was supported by a grant from the NRL program of the Korean Ministry of Science and Technology. Shin, Y.- J.. Lee. J.-H and Kwon, T.-H. have been supported by BK21 program from the Korean Ministry of Education)