• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.285-296
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• 1995

Anatomical studies of sink tissues are required for better understanding the biological plant growth system and energy metabolism. Kinematics of root growth zones of two genotypes of tall fescue (Festuca arundinacea Schreb.) receiving 50 or 200 ppm N were determined. Longitudinal anatomy and cell dynamics of root growth zones were studied and calculated. The root growth zone is organized similarly to the leaf growth zone which has cell division, elongation, and maturation zones, but the root growth zone is only about 3.0 mm long compared to 25 to 30 mm for the leaf growth zone. The root cap extends about 0.4 to 0.5 mm from the apical initial, while the cell elongation zone for both cortical and metaxylem cells extends about 3.3 mm from the apical initial for both genotypes and N levels. Root cap cells elongate from an initial length of about 5$\mu{m}$ long to a final length of about 40$\mu{m}$ before being sloughed. Initial lengths of cortical and metaxylem cells were about 8.5 $\mu{m}$ and 13.0 $\mu{m}$, respectively. Elongation of cortex and metaxylem cell showed sigmoidal curves with final lengths of about 120 $\mu{m}$ for cortex cells and 650 $\mu{m}$ for metaxylem cells. Initial size and final size for both types were not affected by N level, but cell fluxes and cell elongation rates of cortical and metaxylem cells were about double in low N. Cell production rates were about 5 to 6 times higher in cortical cells than in metaxylem cells. Differences in N caused a larger change in cell production rate, duration of cell elongation, and relative cell elongation rate than did the genotypes. These data indicate that N application affects root growth longitudinally by changing cell production rate and elongation rate.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.259-270
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• 2020

Listeria monocytogenes is a gram-positive, facultative anaerobe food pathogen responsible for the listeriosis that mostly occurs during the low-temperature storage of a cold cut or dairy products. To understand the systemic response to a wide range of growth temperatures, L. monocytogenes were cultivated at a different temperature from 10℃ to 42℃, then whole cell proteomic analysis has been performed both exponential and stationary cells. The specific growth rate increased proportionally with the increase in growth temperature. The maximum growth rate was observed at 37℃ and was maintained at 42℃. Global protein expression profiles mainly depended on the growth temperatures showing similar clusters between exponential and stationary phases. Expressed proteins were categorized by their belonging metabolic systems and then, evaluated the change of expression level in regard to the growth temperature and stages. DnaK, GroEL, GroES, GrpE, and CspB, which were the heat&cold shock response proteins, increased their expression with increasing the growth temperatures. In particular, GroES and CspB were expressed more than 100-fold than at low temperatures during the exponential phase. Meanwhile, CspL, another cold shock protein, overexpressed at a low temperature then exponentially decreased its expression to 65-folds. Chemotaxis protein CheV and flagella proteins were highly expressed at low temperatures and stationary phases. Housekeeping proteins maintained their expression levels constant regardless of growth temperature or growth phases. Most of the growth related proteins, which include central carbon catabolic enzymes, were highly expressed at 30℃ then decreased sharply at high growth temperatures.

• Korean Journal of Plant Resources
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• v.35 no.1
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• pp.29-35
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• 2022

Elsholtzia byeonsanensis is a Korean native plant of the Lamiaceae family, and was first introduced in the Korean Journal of Plant Taxonomy. This plant has a short plant length of 20-35 cm, with leathery and glossy leaves. The purple flowers bloom in November, so they are highly useful as potted or ground cover ornamental plants. In this study, tray cell size (128, 162, and 200-cell trays), soil composition [horticultural soil (HS): decomposed granite (DG) 1:1, 1:2, and 1:4 (v:v)], seeding rate (1, 2, and 3 seeds per cell) and additional fertilizer concentrations (0, 250, 500, and 1000 mg/L Hyponex) were tested to find out the optimum seedling growth conditions. As a result of the study, E. byeonsanensis growth increased proportionally as the cell size of the tray increased. The growth was inhibited as the percentage of DG increased. As for the growth according to the seeding rate, plant height, plant width, leaf length, and leaf width decreased as the seeding rate increased, but there was no difference in the number of leaves, stem diameter, and root length. There was an increasing trend in seedling growth as the additional fertilizer concentration increased. Therefore, for producing E. byeonsanensis seedling, it is most effective to fill HS or HS:DG 1:1 in 128-cell trays, sow one seed per cell, and spray the seedling at 1000 mg/L for additional fertilizer.

• KSBB Journal
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• v.9 no.5
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• pp.443-449
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• 1994

Fermentation characteristics of Kluyveromyces fragilis CBS 1555 with Jerusalem artichoke juice, in extractive ethanol fermentation in aqueous two phase systems composed of polyethylene glycol 20000 (PEG) and crude dextran(Dx), were investigated as a function of initial sugar concentrations, concentrations of ethanol formed, or fermentation time. Both specific ethanol production rate increased with decrease in concentrations of PEG and Dx in two-phase systems. Without being related to the compositions of aqueous two-phase system, maximum specific cell growth rate and maximum specific ethanol production rate were showed in the initial sugar concentration fo $80g/\ell$ and $120g/\ell$, respectively. The inhibition effects of ethanol on specific cell growth rate and specific ethanol production rate decreased with decrease in PEG concentration and in the range of 2.5 to 5% Dx. Specific cell growth rate and specific ethanol production rate was fitted as an exponential function and a hyperbolic function, respectively, of the concentrations of ethanol formed. Overall ethanol productivity increased with increase in initial sugar concentrations, and also the required time for the maximum productivity was so. Ethanol production rate by the elapsed fermentation time showed the maximum value in the initial sugar concentration of $160g/\ell$.

• Biomedical Science Letters
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• v.23 no.2
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• pp.49-56
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• 2017

Fibroblast growth factor (FGF)-2 is one of the most effective growth factors to increase the growth rate of mesenchymal stem cells (MSCs). Previously, we reported that low dose of FGF-2 (1 ng/ml) induced proliferation of bone marrow-derived mesenchymal stem cells (BMSCs) through AKT and ERK activation resulting in reduction of autophagy and senescence, but not at a high dose. In this study, we investigated the effects of high dose FGF-2 (10 ng/ml) on proliferation, autophagy and senescence of BMSCs for long term cultures (i.e., 2 months). FGF-2 increased the growth rate of BMSCs in a dose dependent manner for a short term (3 days), while during long term cultures (2 months), population doubling time was increased and accumulated cell number was lower than control in BMSCs when cultured with 10 ng/ml of FGF-2. 10 ng/ml of FGF-2 induced immediate de-phosphorylation of ERK1/2, expression of LC3-II, and increase of senescence associated ${\beta}$-galactosidase (SA-${\beta}$-Gal, senescence marker) expression. In conclusion, we showed that 10 ng/ml of FGF-2 was inadequate for ex vivo expansion of BMSCs because 10 ng/ml of FGF-2 induced growth retardation via ERK1/2 de-phosphorylation and induction of autophagy and senescence in BMSCs.

• KSBB Journal
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• v.10 no.4
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• pp.455-460
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• 1995

Specific growth rate was controlled for the repression of acetic acid formation in the fed-batch fermentation of recombinant Escherichia coli. With controlled specific growth rate, we studied the effect of the specific growth rate on cell growth, glucose consumption, acetic acid formation, and the expression of recombinant protein (${\beta}$-lactamase). High specific growth rate caused the accumulation of glucose and acetic acid, and lowered the production of recombinant protein. However, the addition of methionine recovered the gene expression by alleviating the negative effect of acetic acid at high specific growth rate.

• KSBB Journal
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• v.16 no.1
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• pp.30-35
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• 2001

High cell density culture of Bacillus thuringiensis was conducted in fed-batch culture and TCRC using a bioreactor incorporating ceramic membrane filter. Cell growth of B. thuringiensis in fed-batch culture increased linearly, which was well matched by the results of cell growth modeling. In spite of the slower growth rate during fed-batch culture, no spore formation was observed, which was contrary to the results of continuous culture. Changing culture mode to batch culture after fed-batch operation induced a 2.7$\times$$10^9$ CFU/mL spore concentration using a 300 g/L glucose feed concentration. In TCRC operation incorporating ceramic filter within the bioreactor, the effect of glucose feed concentrations on the cell growth and spore formation of B. thuringiensis was determined. A maximum cell concentration of 1.8$\times$$10^{10}$ CFU/ml, which corresponds to 82.6 g-cell/L, was obtained in the TCRC using a 50 g/L glucose feed concentration. In the TCRC, cell growth increased linearly and glucose concentration was limited, which agreed well with the results of cell growth modeling. No spore formation was observed except when 1 g/L of glucose was fed. Changing to batch culture induced a 1.2$\times$$10^{10}$ CFU/mL of spore concentration, which was the highest spore concentration obtained among the various culture modes examined. The optimal glucose feed rate was found to be 0.55 g-glucose/h.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.878-881
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• 2002

The goal of the current research was to assess the influence of the growth rate of Nocardia amarae on its overall metal binding capacity. Batch sorption isotherms for cadmium (Cd), copper (Cu), and nickel (Ni) showed that Nocardia cells harvested from chemostat cultures at a dilution rate of $0.33d^-1$ had a significantly higher metal sorption capacity than cells grown at 0.5 and $1d^-1$. The cell surface area estimated using a dye technique indicated that pure N. amarae cells grown at a lower growth rate had a significantly more specific surface area than cells harvested from a higher growth rate operation. Accordingly, this difference in the specific surface area seemed to indicate that the higher metal sorption capacity of the slowly growing Nocardia cells was due to their higher specific surface area.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.716-721
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• 1999

It has been known that continuous cultivation of hairy root is difficult to maintain for a long period of time compared to the microbial and callus cultures. Chemostat cultivation was successfully carried out in order to economically produce a plant-based colorant, betacyanin, from red beet hairy root for more than 85 days in a 14-1 fermentor. The result from the chemostat cultivation was compared to those of the batch and fed-batch cultivations of red beet hairy roots. It was shown that hairy root reached its steady state within 50 days of the cultivation, and then maintained for about 25-30 days in a wide range of dilution rates. Total betacyanin production from the continuous process was also calculated to be 2.65g at 0.28(l/d) of dilution rate, compared to 0.196g from fed-batch cultivation. It was found that betacyanin production was a partially growth related process, yielding 0.376 mg/g-fresh wt. cell and $1.89{\times}10^{-5}$ mg/g-fresh wt. cell/d, with 0.92 of correlation factor in a partial growth-product model. It was also shown that the cell growth required was relatively large for maintenance amount of energy at a low dilution rate. The growth of hairy root was inhibited by high light intensity in following a photo-inhibition model. The growth parameters were estimated to be 0.3(l/d), $10.56kcal/\textrm{m}^2/h$,{\;}and{\;}35.81kcal/\textrm{m}^2/h$ for the maximum specific growth rate, half saturation light intensity, and inhibition light intensity, respectively.

• KSBB Journal
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• v.6 no.1
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• pp.1-7
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• 1991

To produce economically important indole alkaloids by cell cultures, we selected protoplastsderived clones (protoclones) of vinca (Catharanthus roseus) for high yields of catharanthine and ajmalicine. Protoplasts were enzymatically isolated from suspension-cultured cells. The highest plating efficiency (1%) was obtained when protoplasts were plated at a density of 1$\times$105 protoplasts/ml in a culture medium solidified with 0.4% Seaplaque agarose. The growth rates of 40 protoclones subcultured on a solid medium varied over a wide range. Protoclone VPC-6, which had the highest growth rate, was observed to produce relatively high yields of catharanthine and ajmalicine when cultured in a liquid medium. Although the original cell line did not produce catharanthine at a detectable level by HPLC, protoclone VPC-10 produced it at a level of 5.9$\mu\textrm{g}$/g fresh weight of cells for 10 days of culture. Under the same conditions, protoclone VPC-15 produced ajmalicine at a level of 133.6$\mu\textrm{g}$/g, of which productivity was improved about ,3 times than that of the original cell line. The results indicate that differences in the growth rate and indole alkaloid yield among the protoclones reflect the somaclonal variation in suspnsion-cultured cells.