• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.142-149
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• 1991

Gardenia callus was induced in MS medium containing $10{\;}{\mu}M$ of 2,4 diphenoxy acetic acid (2,4-D), $1{\;}{\mu}M$ kinetin, and 3% sucrose in the dark. $B_5$ medium was identified to be the most adequate medium for cell growth. Indole-3-acetic acid (IAA) was better growth regulator than 2,4-D not only for cell growth but slso for carotenoid production. Ligt also played a critical role on synthesis of carotenoid. Gardenia cells grown in $B_5$ medium could utilize a polysaccharide, soluble starch, as a carbon source. The cell growth was stimulated in $B_5$ medium fortified with 0.2% yeast extract. The optimum pH for cell growth was 5.7. High density cultures can be maintained by increasing inoculum size and medium concentration accordingly. Specific growth rate and mass doubling time were 0.095 $day^{-1}$ and 7.3 days, respectively. The cell immobilized in alginate tends to formulate more enlarged vacuoles containing yellow pigment compared with those of suspended cell. Carotenoid content of immobilized cell was about $264.4{\;}{\mu}g/g$ fresh weight (F.W.) corresponding twice of the content of suspended cell ($112.08{\;}{\mu}g/g$ F.W.). The color of gardenia cell was shifted from yellow to red when carbohydrase-secreting fungus, Trichoderma reesei, was co-cultivated with gardenia cells.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.23-36
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• 2009

In the present work, the metabolic network of primary metabolism of the slow-growing myxobacterium Sorangium cellulosum was reconstructed from the annotated genome sequence of the type strain So ce56. During growth on glucose as the carbon source and asparagine as the nitrogen source, So ce56 showed a very low growth rate of $0.23\;d^{-1}$, equivalent to a doubling time of 3 days. Based on a complete stoichiometric and isotopomer model of the central metabolism, $^{13}C$ metabolic flux analysis was carried out for growth with glucose as carbon and asparagine as nitrogen sources. Normalized to the uptake flux for glucose (100%), cells recruited glycolysis (51%) and the pentose phosphate pathway (48%) as major catabolic pathways. The Entner-Doudoroff pathway and glyoxylate shunt were not active. A high flux through the TCA cycle (118%) enabled a strong formation of ATP, but cells revealed a rather low yield for biomass. Inspection of fluxes linked to energy metabolism revealed that S. cellulosum utilized only 10% of the ATP formed for growth, whereas 90% is required for maintenance. This explains the apparent discrepancy between the relatively low biomass yield and the high flux through the energy-delivering TCA cycle. The total flux of NADPH supply (216%) was higher than the demand for anabolism (156%), indicating additional reactions for balancing of NADPH. The cells further exhibited a highly active metabolic cycle, interconverting $C_3$ and $C_4$ metabolites of glycolysis and the TCA cycle. The present work provides the first insight into fluxes of the primary metabolism of myxobacteria, especially for future investigation on the supply of cofactors, building blocks, and energy in myxobacteria, producing natural compounds of biotechnological interest.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.35-40
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• 2004

Rotavirus virus-like particle (VLP) composed of VP2, VP6, and VP7 was expressed in the Baculovirus Expression Vector System (BEVS). Sf9 cell, a host of the baculovirus, was cultured from a 0.5-1 spinner flask to the 50-1 bioreactor system. Sf9 cell was maintained at cell density between 3.0E＋05 and 3.0E＋06 cells/ml and grew up to 1.12E＋07 cells/ml in the bioreactor. Growth kinetics was compared under different culture systems and showed similar growth kinetics with 20.1-25.2 h of doubling time. Early exponentially growing cell culture was infected with three recombinant baculoviruses expressing VP2, VP6, and VP7 protein at 1.0, 2.0, and 0.2 moi, respectively. The expression of rotavirus proteins was confirmed by Western blot analysis and its three-layered virus-like structure was observed under an electron microscope. Rotavirus VLP was semipurified and immunized in ICR mice intramuscularly. Rotavirus-specific serum antibody was detected from 2 weeks after the immunization and lasted at least 21 weeks of the post-immunization, indicating its possible use as a vaccine candidate.

• Journal of Preventive Medicine and Public Health
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• v.53 no.3
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• pp.158-163
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• 2020

Objectives: In the current early phase of the coronavirus disease 2019 (COVID-19) outbreak, Bali needs to prepare to face the escalation of cases, with a particular focus on the readiness of healthcare services. We simulated the future trajectory of the epidemic under current conditions, projected the impact of policy interventions, and analyzed the implications for healthcare capacity. Methods: Our study was based on the first month of publicly accessible data on new confirmed daily cases. A susceptible, exposed, infected, recovered (SEIR) model for COVID-19 was employed to compare the current dynamics of the disease with those predicted under various scenarios. Results: The fitted model for the cumulative number of confirmed cases in Bali indicated an effective reproduction number of 1.4. Interventions have decreased the possible maximum number of cases from 71 125 on day 86 to 22 340 on day 119, and have prolonged the doubling time from about 9 days to 21 days. This corresponds to an approximately 30% reduction in transmissions from cases of mild infections. There will be 2780 available hospital beds, and at the peak (on day 132), the number of severe cases is estimated to be roughly 6105. Of these cases, 1831 will need intensive care unit (ICU) beds, whereas the number of currently available ICU beds is roughly 446. Conclusions: The healthcare system in Bali is in danger of collapse; thus, serious efforts are needed to improve COVID-19 interventions and to prepare the healthcare system in Bali to the greatest extent possible.

• Journal of Microbiology
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• v.34 no.2
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• pp.172-178
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• 1996

Methylobacillus sp. strain SK1, which grows only on methanol, was found to grow in the absence of added copper. The doubling time (t$_{d}$ = 1.3 h) of the bacterium growing at the exponential growth phase at 30.deg.C in the absence of copper was the same as that of the cell growing in the presence of copper. The bacterium growing after the exponential phase in the absence of copper, however, grew faster than the cell growing in the presence of copper. Cells harvested after thee arly stationary phase in the presence of copper were found to exhibit no methanol dehydrogenase (MDH) activity, but the amount and subunit structure of the enzyme in the cells were almost the same as that in cells harboring active MDH. Pellets of the cells harvested after the early stationary phase in the presence of copper were pale green. Cell-free extracts prepared from cells harvested at the early stationary phase in the presence of copper were pink and exhibited MDH activity, but it turned dark-green rapidly from the surface under air. The green-colored portions of the extracts showed no MDH activity and contained c-type cytochromes that were oxidized completely. The inactive MDH activity and contained c-type cytochromes that were oxidized completely. The inactive MDH proteins in the green portions were found to have antigenic sites identical to those of the active one as the inactive MDHs in cells grown in the presence of copper. The bacterium was found to accumulate copper actively during the exponential growth phase. MDH prepared from cells grown in the presence or absence of copper was found to be more stable under nitrogen gas than under air. Methanol at 10 mM was found to enhance the stability of the MDH under air.r.

• KSBB Journal
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• v.9 no.5
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• pp.450-456
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• 1994

The effects of sucrose on cell growth and anticancer drug taxol production were investigated in cell suspension cultures of Taxus cuspidata. The cells were cultured at various concentrations of sucrose (20 to $100g/\ell$). The highest specific growth rata was achieved at $40g/\ell$ of sucrose as 0.076 day-1 and the highest final cell density, 34 g DCW/$\ell$ after 25 days of culture, was obtained at $60g/\ell$ of sucrose. The cell yield(Yx/s) was found to be 0.55g cell/g sucrose and doubling time (Td) was 9.12 day. High concentration of sucrose (80, $100g/\ell$) and the addition of osmoticum enhanced the production of taxol significantly. The maximum taxol production was $1.36mg/\ell$ at $80g/\ell$ of sucrose, which was 0.01% as a specific content.

• Imaging Science in Dentistry
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• v.42 no.2
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• pp.89-93
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• 2012

Purpose : Clinicians commonly encounter cases in which it is difficult to determine whether adjacent radiopacities are normal or pathologic. The ideal radiopacity of composite resin is equal to or higher than that of the same thickness of aluminum. We aimed to investigate the possible effects of different curing times on the post-24-hour radiopacity of composite resins on digital radiographs. Materials and Methods : One mm thick samples of Filtek P60 and Clearfil resin composites were prepared and cured with three regimens of continuous 400 mW/$cm^2$ irradiance for 10, 20 and 30 seconds. Along with a 12-step aluminum step wedge, digital radiographs were captured and the radiopacities were transformed to the equivalent aluminum thicknesses. Data were compared by a general linear model and repeated-measures of ANOVA. Results : Overall, the calculated equivalent aluminum thicknesses of composite resins were increased significantly by doubling and tripling the curing times (F(2,8)=8.94, p=0.002). Notably, Bonferroni post-hoc tests confirmed that the radiopacity of the cured Filtek P60 was significantly higher at 30 seconds compared with 10 seconds (p=0.04). Although the higher radiopacity was observed by increasing the time, other comparisons showed no statistical significance (p>0.05). Conclusion : These results supported the hypothesis that the radiopacity of resin composites might be related to the duration of light curing. In addition to the current standards for radiopacity of digital images, defining a standard protocol for curing of dental materials should be considered, and it is suggested that they should be added to the current requirements for dental material.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.3
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• pp.335-343
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• 2018

Objective: Remarkable difference in cellular activity was found between early and late subpassaged embryonic stem cell (ESCs) lines, which can be created by subtle changes in cell manipulation protocol. This study subsequently examined whether post-thaw subculture of early subpassaged ESC lines could further affect the activity of the ESCs. Methods: Fresh (as a control treatment) or cryopreserved F1 hybrid (B6CBAF1) early ESC lines (C57BL/6xCBA) of the 4 (P4) or the 19 passage (P19) were subcultured once, twice or six times under the same condition. The post-thaw survival of the ESCs was monitored after the post-treatment subculture and the ability of cell proliferation, reactive oxygen species (ROS) generation, apoptosis and mitochondrial ATP synthesis was subsequently examined. Results: Regardless of the subculture number, P19 ESCs showed better (p<0.05) doubling time and less ATP production than P4 ESCs and such difference was not influenced by fresh or cryopreservation. The difference between P4 and P19 ESC lines became decreased as the post-treatment subculture was increased and the six times subculture eliminated such difference. Similarly, transient but prominent difference in ROS production and apoptotic cell number was detected between P4 and P19 ESCs only at the 1st subculture after treatment, but no statistical differences between two ESC lines was detected in other observations. Conclusion: The results of this study suggest that post-thaw subculture of ESCs under the same environment is recommended for standardizing their cellular activity. The activity of cell proliferation ability and ATP synthesis can be used as parameters for quality control of ESCs.

• Membrane Journal
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• v.30 no.1
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• pp.66-77
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• 2020

The current study focused on the effect of twisting hollow fibers (HFs) in a module during forward osmosis operation mode. Computational fluid dynamics simulation was employed for a straight HF module and twisted modules with five different angles to predict the mass transfer and observe the draw solution profile in terms of concentration and pressure. The simulation results showed that when the membranes were twisted, the concentration was distributed more evenly and the pressure at the module outlet increased gradually as the twisting angle increased. As pressure at the outlet increased, the fluid velocity inside the membrane decreased and the residence time of fluid increased, thereby facilitating mass exchange across the membrane. This is evidenced by a doubling of the ratio of water flux through the membrane in module flux when the HFs were twisted.

• Development and Reproduction
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• v.24 no.3
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• pp.207-214
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• 2020

Primary cell culture is a sufficient method frequently used to study the cellular properties and mechanisms of isolated cells in a controlled environment. In this study, an embryonic cell line (FGBC8) derived from the blastula stages of embryos of olive flounder Paralichthys olivaceus was developed. Furthermore, conditions for optimal long-term maintenance of this primary embryonic cell culture were investigated. Morphologically, FGBC8 cells were composed primarily of epithelial-like cells. FGBC8 cells were subcultured for >160 passages over ~830 days. The doubling time of FGBC8 cells was 73.8 h, and the modal diploid chromosome number was 48. FGBC8 cells transfected with green fluorescence protein (GFP)-expression plasmid exhibited a strong signal 48 h after transfection. Consequently, we demonstrated that fish serum is a crucial supplement for the long-term survival and maintenance of comparable morphology in these primary embryonic cells. Our results can be used as a guide for primary embryonic cell cultures for other fish species and may be useful for cell biotechnological applications.