• KSBB Journal
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• v.8 no.3
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• pp.217-223
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• 1993

Methods for production of ${\gamma}$-Polyglutamic acid( ${\gamma}$-PGA ) by an alkalophilic Alcaligenes sP. were investigated for batch and continuous culture processes. Both quantity and productivity of ${\gamma}$-PGA by Alcaligenes sp. in batch culture were gradually increased with the increase of glucose concentration up to 50g/l , but the maximal production yield of 63% was obtained at 10g/l of glucose concentration. The highest specific growth rate was about $0.25hr^{-1}$ at 50un of glucose concentration, and substrate inhibition was observed at above 50g1f of glucose concentration. The highest ${\gamma}$-PGA formation about 11g/l in a batch system was obtained at 31'C, pH 10.0 and 87rpn Productivity of 2.80g/l/hr for continuous cultivation was 9 times higher than the productivity for batch cultivation.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.21-32
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• 1996

Rhizoctonia solani 균주들의 각 균사융합군 및 배형별 72종의 기주작물에 대한 병원성을 접종실험에 의해 조사하였다. 33종의 작물에서 단독으로 분리된 균사융합군 및 배양형은 그 기주작물에 병원성이 강하였으며, 8종의 작물에서 단독으로 분리된 것들은 병원성이 약하거나 강하였고, 6조의 작물에서 단독으로 분리도니 것들은 병원성이 약하거나 없었다. 26종의 작물에서 같이 분리된 균사융합군 및 배양형은 그 기주작물에 대한 병원성이 대부분 다르거나 간혹 비슷했다. AG-1(IA)는 1종을 제외한 기주작물에 잎마름병 혹은 잎썩음병과 잎집무늬마름병을 일으켰다. AG-1(IB)는 19종의 기주작물에 잘록병과 잎마름병 혹은 잎썩음병을 일으켰으나, 9종의 기주작물에는 병징을 약하게 유발시키거나 혹은 유발시키지 못했다. AG-1(IC)는 2종의 유채속작물에 잘록병과 밑둥썩음병 혹은 잎썩음병을 일으켰다. AG-2-1은 1종을 제외한 기주작물에 잘록병, 밑둥썩음병, 관부썩음병, 눈마름벼, 뿌리썩음병, 잎마름병을 일으켰다. AG-202(IIIB)는 기주작물에 뿌리 및 줄기썩음병, 잎마름병, 잘록병, 잎자루썩음병을 일으켰다. AG-2-2(IV)는 기주작물에 잘록병, 관부썩음병, 줄기썩음병, 라이족토니아마름병을 일으켰다. AG-3은 감자에 검은무늬썩음병을 일으켰다. AG-4는 42종의 기주작물에 여러 가지 병을 일으켰으나, 3종의 기주작물에는 잘록병, 눈마름병, 잎집무늬마름병을 일으켰으나, 9종의 기주작물에는 병징을 약하게 유발시키거나 혹은 유발시키지 못했다.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.13-17
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• 1995

In order to induce haploid plant through pollen culture, pollens of Paeonia albiflora were cultured on MS liquid medium The development of micospore through pollen culture was examined The effect of low temperature (5$^{\circ}C$, 10 days) pretreatment on callus induction and embryogenesis in pollen culture was not evident Calli derived from pollen gave rise to globular embryos when transferred onto solid medium containing 0.5 mg/, 2,4-L. The effect of low temperature pretreatment and medium. combination to pollen viability was unrecognized. Pollen viability was reduced as the culture proceeded.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.527-533
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• 2006

The purpose of this study is to improve the culturability of a indica type rice cultivar, IR 36, using DNA marker associated with the ability of plant regeneration in anther and seed culture. The varietal difference of ability of callus formation and plant regeneration was investigated in anther and seed culture of 8 rice cultivars. Three japonica rice cultivars showed to have better culturability than those of tongil and indica type genotypes. But two indica/japonica lines, 'MGRI 079' and 'MGRI 036', which were selected to have good culturability in previous study showed the highest regenerability (20%) in anther culture of 8 rice cultivars. Thirty four $BC_2F_4$ lines were selected by marker screening using RZ400 for 100 $BC_2F_4$ lines derived from a cross $'MGRI\;079/IR\;36^{^*3}'$. The frequency of callus formation of 30 $BC_2F_4$ lines was higher than those of 'IR 36' in anther culture of the selected $BC_2F_4$ lines. The ability of plant regeneration of 15 lines was higher than that of 'IR 36' in the seed culture of 34 $BC_2F_4$ lines. A promising line, $BC_2F_4-28$, was selected to have better culturability in the anther and seed culture of the $BC_2F_4$ lines. The heading date and grain shape of the $BC_2F_4-28$ was similar to 'IR 36'. In seed culture of 50 $BC_4F_3$ lines derived from a rice cross $'MGRI\;079/IR\;36^{^*5}'$, 11 lines including $BC_4F_3-3$ showed to have higher regenerability compared with 'IR 36'. The highest frequency of plant regeneration (11%) was obtained from $BC_4F_3-46$ in seed culture of the $BC_4F_3$ lines.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.181-187
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• 1991

We previously showed that transient exposure of Rana dybowskii follicles to exogenous cAMP in vitro could induce meiotic maturation. The present experiments were carried out to acertain whether the exogenous cAMP penetrate into the follicles. Isolated follicles were precultured in the medium containing cAMP (2.5 mM) for 6 hours and then cultured further in plain medium for 18 hours. The change of intrafollicular cAMP levels during the culture period were examined by utilizing cAMP radioimmunoassay (RIA). The intrafollicular levels of cAMP increased about thirty times of the basal level (about 3 p mole/follicle) in two hours and reached a peak in six hours (170 p mole/follicle) during the preculture period. However, when the follicles were transferred to plain medium, the levels decreased markedly in six hours to very low levels (about 10 p mole/ follicle), and kept the same levels thereafter. But the levels did not decrease to the basal levels. The increase and decrease of the intrafollicular cAMP was not affected by the presence of isobutyl methylxanthine (IBMX) or progesterone. The data suggest that exogenous cAMP pene-trate into the follicles and the cAMP accumulated by the follicles are degraded very rapidly.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.193-198
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• 1999

The optimal culture condition of Bacillus sp. P16 was investigated for production of an extracellular endo-splitting chitosanase. The best carbon and nitrogen sources for the chitosanase production were chitosan and tryptone, respectively. The best condition for the maximum activity was at $37^{\circ}C$ in a medium containing 0.5% powdered chitosan, 1% tryptone, and 1% NaCl(at initial pH 7.0) in a rotary shaker(200 rpm). In a jar fermenter, the culture duration shortened to $6{\sim}12$ hr for maximum activity and the enzyme activity increased about 100% compared with that of flask culture.

• Korean journal of applied entomology
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• v.21 no.1 s.50
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• pp.15-18
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• 1982

The integrated soil improvement practice reduced neck blast incidence by ranging from 6.3 to 59.5 percent compared to control plot. However, effect of integrated soil improvement practice in reducing neck blast incidence was greater in Tongil type cultivars. On the contrary, mean value of plant height of eleven rice cultivars was taller by 6.4cm in the integrated soil improvement plot with 2.3 more tillers than that of control plot. As a result, yield increase of milled rice by metric tons per hectare was 24.1 percent in the integrated soil improvement plot.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.345-350
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• 2002

바이오테크놀로지(BT, biotechnology)는 21세기의 첨단과학기술로서 생명공학, 생물공학, 생물이용기술 등으로 불리우고 있으며(일농기학회, 2000), 이 중 실용화되고 있는 기술중의 하나가 식물조직의 배양기술이다(백, 1993), 현재 우리나라에서는 나리, 호접란 등의 우량묘 대량증식을 위하여 조직배양기술을 이용하고 있으나 배양공정의 대부분이 인력에 의존하고 있고 배양묘 생산에 소요되는 비용의 약 60% 정도가 노동비용에서 발생되고 있다(정, 1995). 따라서 배양묘 생산의 여러 과정 중에서 수작업에 의한 작업부분을 로봇 화하여 배양묘 생산비용을 절감하려는 연구개발이 활발히 수행되고 있으며, 이중 주목을 받고 있는 것은 배양기에서 증식된 소식물체의 적출, 절단, 이식과 같은 추후의 증식과정이다 이 공정은 노동집약적일 뿐만 아니라 공정의 수작업에 따른 절단의 불균일성, 품질저하, 조작의 미숙련성, 잡균오염의 위험성 등의 문제점이 로봇화로 해결 가능하기 때문이다. (중략)

• KSBB Journal
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• v.15 no.1
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• pp.100-105
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• 2000

Optimal medium composition, culture conditions, characteristics of phase variation and activity of insecticidal toxin by Xenorhabdus nematophilus isolated and identified from Korean entomopathogenic nematode Steinernema carpocapsae were examined. Optimal medium composition of this strain was 50-70 g/L yeast extract, 3 g/L $K_{2}HPO_{4}$, 1g/L $NH_{4}H_{2}PO_{4}$, 2g/L ${MgSO}_4$$\cdot$${7H}_{2}O$, 10g/L NaCl and, these, yeast extract was found as a limiting nutrient for cell growth. When Monod equation was applied, maxmum specific growth rate and Monod constant were estimated as 0.13 $hr^{-1}$ and 20g/L, respectively. The pH of culture medium increased up to 8.5-9.5 regardless of initial pH 6-7 as the cells continued to grow. The specific growth rate in a 7 L fermentor was 0.18 $hr^{-1}$, which was enhancement 1.4 fold compared to a flask culture. In case of phase variation, phase I fraction was maintained above 90% at the stationary phase for both flask and fermentor cultures. According to oral toxicity test of Gallena mellonella by Xenorhabdus nematophilus, the addition of cell pellets into feed inhibited normal growth of insect larvae and killed completely then after 20 days cultivation. When culture supernatant of this strain was injected into hemolymph of insect larva, the toxicity was strongest at 24hr cultivation in the early exponential phase and gradually decreased as the culture time proceeded.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.91-97
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• 1994

To improve the productivity of peroxidase (POD) of cell line SP-47 derived from cell suspension cultures of sweet potato (Ipomoea batatas (L) Lam.cv White Star), we optimized culture conditions including the composition and concentration of plant growth regulators and carbon source, and the cell inoculum size. When one g (fr wt) of cells was inoculated into 50 mL TL medium supplemented with l mg/L 2,4-D and 30g/L sucrose in 300 mL Erlenmeyer flask at 25$^{\circ}C$ in the dark (100rpm), the POD activity per g cell dry wt was maximized to be about 6,800 units after 25 days of subculture, which was about 30 times higher than that of intact roots of horseradish plants grown in the greenhouse, but the cell growth was maximum after 15 days of subculture. The protein content per g cell dry wt maintained almost plateau and after 25 days of subculture decreased as culture Proceeded further whereas the POD specific activity (unit/mg protein) was about two times higher after subculture and continuously increased from 12 days to the end of cultures (40 days). The POD isozyme patterns showed almost the same regardless of cell growth stage, but some acidic isozymes were slightly increased after 25 days of subculture. These results indicate that POD activity in suspension cultures of sweet potato is closely associated with cell growth and stresses derived from cell culture renditions and medium depletion. Due to its high POD activity the SPL47cell line seems to be suitable for the mass production of POD.