• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.3
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• pp.189-193
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• 2001

Critical cell density (CCD), the maximum cell concentration without mutual shading in algal cultures, can be used as a new operating parameter for high-density algal cultures and for the application of the flashing light effect on illuminated algal cultures. CCD is a function of average cell volume and light illumination area. The CCD is thus proposed as an index of estimation of mutual shading in algal cultures. Where cell densities are below the CCD, all the cells in photobioreactors can undergo photosysnthesis at their maximum rate. At cell densities over CCD, mutual shading will occur and some cells in the illumination chamber cannot grow photoautotrophically. When the cell concentration is higher than the CCD, specific oxygen production rates under flashing light were higher than those under continuous light. The CCD was found to be a useful engineering parameter for the application of flashing light, particularly in high-density algal cultures.

• Journal of Plant Biotechnology
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• v.5 no.2
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• pp.121-129
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• 2003

Callus cultures of Azadirachta indica flower petals were established on MS medium supplemented with naphthalene acetic acid (1 mg/L), kinetin (0.5 mg/L) and sucrose $(3\%\;w/v)$. Cell cultures of Azadirachta indica were established and studied the growth and production kinetics. Half 85 medium supplemented with dicamba (2 mg/L), kinetin (1 mg/L) and sucrose $(3\%\;w/v)$ was found to be suitable for initiation and maintenance of cell cultures from the calli. MS medium supplemented with naphthalene acetic acid (NAA) (1 mg/L), kinetin (0.5 mg/L) and sucrose $(3\%\;w/v)$ was found to be suitable as production medium. Around $80\%\;(0.05\%\;w/v)$ of azadirachtin was found to be intracellular. The effect of various precursors, elicitors, permeabilizing agents and growth retardants in cell cultures was studied. The addition of precursors sodium acetate (10 mg/L), squalene (10 mg/L), isopentenyl pyrophosphate (1 mg/L) and geranyl pyrophosphate (1 mg/L) to the cell cultures on day 3 has shown significant increase in bioproduction of azadirachtin $(64.94{\pm}4.40\;mg/L,\;72.81{\pm}0.04\;mg/L,\;51.63{\pm}1.26\;mg/L\;and\;30.70{\pm}0.28\;mg/L\;respectively)$ over the control cultures $(4.70{\pm}0.27 mg/L)$. $5\%$ v/v cell extracts of Fusarium solani has shown moderate increase in the content of azadirachtin $(5.71{\pm}0.34\;mg/L)$ when compared to control cultures $(2.40{\pm}0.56\;mg/L)$. The addition of methyl jasmonate $(500\;{\mu}M/L)$ on day 3 has shown $\~4$ fold improvement in bioproduction of azadirachtln $(6.92{\pm}0.11\;mg/L)$ when compared to control cultures $(1.63{\pm}0.02\;mg/L)$. There was no significant effect of the studied growth retardants and permeabilizing agents on bioproduction of azadirachtin. Cells are cultivated in large volumes using the effective precursors.

• KSBB Journal
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• v.15 no.4
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• pp.405-407
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• 2000

A novel recovery method was developed to obtain the plant cell and its debris from Taxus chinensis cell cultures By pH control of plant cell cultures plant cell and debris was precipitated. The best pH is between 1.8 and 2.2 to obtain the precipitate of the plant cell and debris. Also paclitaxel is stable in this acidic conditions. This method is very simple an efficient to recover the plant cell and debris from plant cell cultures.

• Korean Journal of Medicinal Crop Science
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• v.12 no.5
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• pp.366-371
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• 2004

Aconitine alkaloids produced from cell suspension cultures of Aconitum napellus for the first time. The effects of various culture conditions on cell biomass and aconitine accumulation in cell suspension cultures were investigated. Suspension cell cultures of A. napellus were established by transferring callus tissues from leaf explants onto liquid MS medium supplemented with $1\;mg/l$ NAA and $0.1\;mg/l$ kinetin. Among the culture media tested, MS medium had a pronounced effect on cell growth and aconitine accumulation. The maximum dry cell weight was obtained at inoculum size of 3 g (FCW) per flask and in MS medium supplemented with 5% sucrose after 8 weeks. The addition of salicylic acid (SA) and yeast extract (YE) in the MS medium enhanced aconitine accumulation. Using a proper combination of culture condition and supplements, aconitine content could reach 0.043% (dry weight basis), that was $2.5{\sim}3$ fold higher that detected in control cultures.

• The Journal of the Korean Society for Microbiology
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• v.16 no.1
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• pp.83-89
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• 1981

Japanese encephalitis has been prevalent for long time in the Far East and many patients have been reported in both South East and Mid-West Asia recently. Recently, vaccine was used in prevention of this viral disease of man which was derived from formalin inactivated virus inoculated into mouse brain, but live attenuated active vaccine for human is not developed yet. Author inoculated Japanese encephalitis virus into several cell culture strains for development of live attenuated encephalitis virus strain and the results were as follows: 1. Japanese encephalitis virus was inactivated rapidly in cell free medium at $36^{\circ}C$ and totally inactivated by 72 hours. 2. In growth curve of Japanese encephalitis virus in HeLa cell cultures, maximal multiplication of the virus was occured at 4th day and virus multiplication was continued for at least 12 days. 3. After succeeding passage of the virus in HeLa cell cultures and human esophagus epithelial cell cultures, infectivity of virus for mice was disappeared from 2nd passage in HeLa cell cultures and 3rd passage in esophagus epithelial cell cultures. 4. In inoculation to monkey kidney epithelial cells and chick embryo cell cultures, infectivity of the virus for mice was continued after 10th passages.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.43-46
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• 1979

Curing the studies on the mechanism of the nodule formation and the infection of rhizobia using the continously cultured plant cell tissues, it was found that some calluses possess high nitrogen fixation activity. This experiment was conducted to know the differences among the calluses and the Rhizobia. The results obtained were as follows; 1) In a single inoculation the nitrogenase activity of soybean cell cultures-rhizobium was moderately higher than non-leguminous cell cultures, however, in the mixing inoculation that was reversely found. 2) Host factor, which was characteristics for the nodule formation and the nitrogenase activity, was not appeared generally in the plant cell cultures except for Kuamusume and Toyozuzu in soybean, and Datura in non-leguminous cell cultures. 3) In the 012 rhizoblium cultured on soybean cell cultures and in the 010, 023 and 024 rhizobia cultured on non-leguminous cell cultures the nitrogenase activity higher than the others.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.631-638
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• 1998

Studies were made to elucidate the cell growth and the production of camptothecin and its derivatives in cell cultures of Camptotheca acuminata. High resolution HPLC chromatograms to analyze camptothecin and 10-hydroxycamptothecin in lactone and carboxylate forms were obtained with a fluorescence detector. Calli inductions were optimized with the young stem of explant on Schenk and Hildebrandt (SH) medium supplemented with 5 mg/l $\alpha$-naphthaleneacetic acid (NAA), 0.2 mg/l 6-benzylamino purine (BAP), 2.0% sucrose, and 0.5% agar. The hybrid medium, a mixture of SH and Murashige and Skoog (MS) salts, was developed for homogeneous suspension cultures without large cell aggregates. The optimum phytohormone concentrations for successful suspension cultures were 1.0mg/l of 2,4-D and 0.5 mg/l of kinetin. The highest growth in suspension cultures was observed when 49.7% (w/w) of the cells was composed of small aggregates which were below 0.1 mm in diameter. Time course changes of cell growth and camptothecin production showed that camptothecin accumulation was started at the end of the growth phase and the maximum content was obtained 10 days after inoculation. Yeast extract elicitor increased camptothecin accumulation 4 times. Methyl jasmonate and jasmonic acid also increased camptothecin production 6 and 11 times, respectively.

• Archives of Pharmacal Research
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• v.20 no.2
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• pp.103-109
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• 1997

The effects of ginseng total saponins (GTS) on hypoxic damage of primary cultures of astrocytes were studied. Hypoxia was created by placing cultures in an air tight chamber that was flushed with 95% $N_2/5%CO_2$ for 15 min before being sealed. Cultures showed evidence of significant cell injury after 24 h of hypoxia (increased lactate dehydrogenase (LDH) content in the culture medium, cell swelling and decreased glutamate uptake and protein content). Addition of GTS (0.1, 0.3 mg/ml) to the cultures during the exposure to hypoxic conditions produced dose-dependent inhibition of the LDH efflux. GTS (0.1, 0.3 mg/ml) also produced significant inhibition of the increased cell volume of astrocytes measured by $[^3H]$ O-methyl-D-glucose uptake under the hypoxic conditions. Decreased glutamate uptake and protein content was inhibited by GTS. These data suggest that GTS prevents astrocytic cell injury induced by severe hypoxia in vitro.

• Journal of Plant Biotechnology
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• v.6 no.2
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• pp.125-130
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• 2004

Callus and cell suspension cultures of Eurycoma longifolia Jack could be an alternative supply of 9-hydroxycanthin-6-one and 9-methoxycanthin-6-one. The callus tissues were initiated from leaves of different trees. The friable calli were used for the preparation of the cell suspension cultures of E. longifolia. The leaf explant of tree Eu-9 produced the most callus and also induced high cell biomass in the cell suspension culture, but it produced low quantity of 9-methoxycanthin- 6-one and 9-hydroxycanthin-6-one. The leaf explant from tree Eu-8 produced low quantity of callus and cell biomass, but produced the highest quantity of 9-methoxycanthin- 6-one and 9-hydroxycanthin-6-one. Optimum production of cell biomass was obtained on cell culture medium with pH 5.75 prior to autoclaving, but high alkaloids content could be induced in culture medium in acidic condition with pH 4.75 and 5.25 prior to autoclaving.

• Journal of Plant Biotechnology
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• v.36 no.4
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• pp.309-319
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• 2009

Transgenic plant cell cultures for the production of biopharmaceuticals including monoclonal antibodies, recombinant proteins have been regarded as an alternative platform in addition to traditional microbial fermentation and mammalian cell cultures. Plant-made pharmaceuticals (PMPs) have several advantages such as safety, cost-effectiveness, scalability and possibility of complex post-translational modifications. Increasing demand for the quantity and diversity of pharmaceutical proteins may accelerate the industrialization of PMP technology. Up to date, there is no plant-made recombinant protein approved by USFDA (Food and Drug Administration) for human therapeutic uses due to the technological bottlenecks of low expression level and slight differences in glycosylation. Regarding expression levels, it is possible to improve the productivity by using stronger promoter and optimizing culture processes. In terms of glycosylation, humanization has been attempted in many ways to reduce immune responses and to enhance the efficacy as well as stability. In this review article, all these respects of transgenic plant cell cultures were summarized. In addition, we also discuss the general characteristics of plant cell suspension cultures related with bioreactor design and operation to achieve high productivity in large scale which could be a key to successful commercialization of PMPs.