• Weed & Turfgrass Science
• /
• v.2 no.2
• /
• pp.202-206
• /
• 2013

Biocontrol potential of an isolate of Helicosporium spp. against Rhizoctonia solani, Fusarium oxysporium and Phytophthora drechsleri was evaluated in vitro and in vivo. A selected biocontrol agent designated as Helicosporium 0635BP strongly inhibited growth and lysed mycelium of Rhizoctonia solani and Fusarium oxysporium on PDA. Autoclaved culture filtrate of the agent also completely inhibited growth of the turfgrass large patch pathogen, R. solani AG2-2 IV at the concentration of 50 ml $L^{-1}$. The pathogen was killed when dipped under the 20% filtrate for four hours or 50% for one hr. In a field trial, plots applied with the crude or times diluted culture filtrate showed 100% control efficacy of the turfgrass large patch as a chemical applied for a comparison. Results indicated that Helicosporium 0635BP is a promising biocontrol agent on control of the turfgrass large patch disease and its culture filtrate contained unknown heat suitable antifungal substance (s). Further studies on mass production, purification and identification of the unknown compound (s) are in progress for practical use.

• Journal of Life Science
• /
• v.29 no.10
• /
• pp.1126-1135
• /
• 2019

From a sample of bamboo byproduct, the protease-producing yeast strain CO-1 was newly isolated. Strain CO-1 is spherical to ovoid in shape and measures $3.1-4.0{\times}3.8-4.4{\mu}m$. For the growth of strain CO-1, the optimal temperature and initial pH were $30^{\circ}C$ and 4.0, respectively. The strain was able to grow in 0.0-15.0%(w/v) NaCl and 0.0-9.0%(v/v) ethanol. Based on a phylogenetic analysis of its 18S rDNA sequences, strain CO-1 was identified as Pichia anomala. The extracellular protease produced by P. anomala CO-1 was partially purified by ammonium sulfate precipitation, which resulted in a 14.6-fold purification and a yield of 7.2%. The molecular mass of the protease was recorded as approximately 30 kDa via zymogram. The protease activity reached its maximum when 1.0%(w/v) CMC was used as the carbon source, 1.0%(w/v) yeast extract was used as the nitrogen source, and 0.3%(w/v) $MnSO_4$ was used as the mineral source. The protease revealed the highest activity at pH 7.0 and $30^{\circ}C$. This enzyme maintained more than 75% of its stability at a pH range of 4.0-10.0. After heating at $65^{\circ}C$ for 1 hr, the neutral protease registered at 60% of its original activity. The protease production coincided with growth and attained a maximal level during the post-exponential phase.

• The Korean Journal of Mycology
• /
• v.50 no.1
• /
• pp.31-40
• /
• 2022

We aimed to produce a potent β-glucuronidase inhibitor from wild yeast that could inactivate toxic substances in the colon. Culture supernatants and cell-free extracts of non-pathogenic wild yeasts were prepared and their β-glucuronidase inhibitory activities were measured. Cell-free extract from Candida oleophila WP5-19-1 showed the highest β-glucuronidase inhibitory activity (49.0%). The β-glucuronidase inhibitor was maximally produced (IC₅₀ value; 8.4 mg) when C. oleophila WP5-19-1 was cultured in potato dextrose medium containing 5% dextrose (initial pH; 6.0) at 30℃ for 24 hours. β-glucuronidase inhibitor of C. oleophila WP5-19-1 was partially purified by trypsin hydrolysis, ultrafiltration (3 kDa), and Sephadex G-50 filtration. The partially purified β-glucuronidase inhibitor was stable from 30℃ to 60℃ and at pH 6.0 9.0, and showed residual inhibitory activity of about 80%.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.13 no.3
• /
• pp.147-151
• /
• 2009

Purpose: 2-[$^{18}F$]Fluoro-2-deoxy-D-glucose ([$^{18}F$]FDG) particularly plays as a important role in Positron Emission Tomography (PET) imaging in nuclear medicine. Domestic [$^{18}F$]FDG auto synthesizers are installed in Seoul National University Bundang Hospital (SNUBH) at June 2008, these modules were known that it's synthetic yields were guaranteed in average $45{\pm}5%$ so far. To improve yields and convenience of domestic [$^{18}F$]FDG auto synthesizer, numerous trials in reaction time, base concentration, pressure and temperature were performed to increase [$^{18}F$]FDG yields. Materials and Methods: Several synthetic factors (temperature, time and pressure) and shortcoming were corrected based on many evaporation test. Syringe dispensing of tetra-butylammonium bicarbonate (TBAB) was replaced with micro pipette to prepare tetrabutyl ammonium fluoride salt ([$^{18}F$]TBAF). Troublesome refill of liquid nitrogen every 2 hours which was used to protect vacuum system was changed to charcoal cartridge, base guard filter. To monitor the volume of delivered $[^{18}O]OH_2$ from cyclotron by surveillance camera, we set up the volumetric vial on the cover of the module. In addition to, the recovery vial was added in [$^{18}F$]FDG production system to recover [$^{18}F$]FDG loss due to the leak of valve ($V_{13,14}$) in [$^{18}F$]FDG purification process. Results: When we used micro pipette for adding TBAB ($30\;{\mu}L$ in 12% $H_2O$ in acetonitrile), this quantitative dispensation has enabled to improve $5.5{\pm}1.7%$ residual fluorine-18 activity in fluorine separation cartridge compared to syringe adding. Besides, the synthetic yields of [$^{18}F$]FDG has increased $58{\pm}2.6%$ (n=19), $58{\pm}2.9%$ (n=14), $60%{\pm}2.5%$ (n=17) for 3 months. The life cycle of charcoal cartridge and base vacuum was 3 months prior to filling liquid nitrogen every 2 hours and additional side separator can prevent pump corrosion by organic solvent. After setting of volumetric indicator vial, the operator can easily monitor the total volume of irradiated $[^{18}O]OH_2$ from cyclotron. The recovery vial can be used for the stabilizer when an irregular [$^{18}F$]FDG loss was generated by the leak of valves ($V_{13,14}$). Conclusions: We has optimized appropriate synthetic conditions (temperature, time, pressure) in domestic [$^{18}F$]FDG auto synthesizer. In addition to, the remodeling with several accessories improve yields of domestic [$^{18}F$]FDG auto synthesizer with reliable reproducibility.

• Journal of Plant Biotechnology
• /
• v.40 no.3
• /
• pp.169-177
• /
• 2013

Recently, the number of people with diabetes is rapidly increasing, coupled with the fact that the insulin market is remarkably increasing. Therefore, molecular farming for plant-derived pharmaceutical protein production is reported as becoming more attractive than ever. In this study, we carried out experiments step by step for development of recombinant insulin constructs, which were transformed into E. coli system, in vitro transcription and translation system, and tobacco cells. At first, recombinant proinsulin protein was successfully produced in in vitro transcription and translation system with wheat germ extract. After which, recombinant construct of prominiinsulin encoded a fusion protein of 7.8 kDa with trypsin cleavage sites at N terminus and C terminus of minimized C-peptide was tried to in vitro expression using E.coli culture. After purification with His-tag column, the resulting recombinant prominiinsulin protein was processed with trypsin, and then checked insulin biosynthesis by SDS-PAGE and western blot analysis with anti-insulin monoclonal antibody. The immunoreactive product of trypsin-treated miniinsulin was identical to the predicted insulin hexamer. The construct of 35S promoter-driven preprominiinsulin recombinant gene with signal peptide region for ER-targeting and red fluorescence protein gene [N terminus ${\rightarrow}$ tobacco E2 signal peptide ${\rightarrow}$ B-peptide (1-29 AA) ${\rightarrow}$ AAK ${\rightarrow}$ A-peptide (1-21 AA) ${\rightarrow}$ RR ${\rightarrow}$ His6 ${\rightarrow}$ KDEL ${\rightarrow}$ C terminus] was transformed into BY-2 tobacco cells. A polypeptide corresponding to the 38-kDa molecular mass predicted for fusion protein was detected in total protein profiles from transgenic BY-2 cells by western analysis. Therefore, this recombinant preprominiinsulin construct can be used for generation of transgenic tobacco plants producing therapeutic recombinant insulin.

• BMB Reports
• /
• v.52 no.8
• /
• pp.496-501
• /
• 2019

Conventionally, immunotoxins have been produced as a single polypeptide from fused genes of an antibody fragment and a toxin. In this study, we adopted a unique approach of chemical conjugation of a toxin protein and an antibody fragment. The two genes were separately expressed in Escherichia coli and purified to high levels of purity. The two purified proteins were conjugated using a chemical linker. The advantage of this approach is its ability to overcome the problem of low recombinant immunotoxin production observed in some immunotoxins. Another advantage is that various combinations of immunotoxins can be prepared with fewer efforts, because the chemical conjugation of components is relatively simpler than the processes involved in cloning, expression, and purification of multiple immunotoxins. As a proof of concept, the scFv of trastuzumab and the PE24 fragment of Pseudomonas exotoxin A were separately produced using E. coli and then chemically crosslinked. The new immunotoxin was tested on four breast cancer cell lines variably expressing HER2. The chemically crosslinked immunotoxin exhibited cytotoxicity in proportion to the expression level of HER2. In conclusion, the present study revealed an alternative method of generating an immunotoxin that could effectively reduce the viability of HER2-expressing breast cancer cells. These results suggest the effectiveness of this method of immunotoxin crosslinking as a suitable alternative for producing immunotoxins.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.4
• /
• pp.349-358
• /
• 2007

In order to understand biogeochemical cycles of organic carbon in the permeable intertidal sandy sediments of the Nakdong estuary, we estimated the organic carbon production and consumption rates both in situ and in the laboratory. The Chl-a content of the sediment and the nutrient concentrations in below surface pore water in the sandy sediment were lower than in the muddy sediment. The sediment oxygen consumption rates were relatively high, especially when compared with rates reported from other coastal muddy sediments with higher organic carbon contents. This implied that both the organic carbon degradation and material transport in the sandy sediment were enhanced by advection-related process. The simple mass balance estimation of organic carbon fluxes showed that the major sources of carbon in the sediment would originate from benthic microalgae and detrital organic carbon derived from salt marsh. The daily natural biocatalzed filtration, extrapolated from filtration rates and the total area of the Nakdong estuary, was one order higher than the maximum capability of sewage plants in Busan metropolitan city. This implies that the sandy sediment contributes greatly to biogeochemical purification in the area, and is important for the re-distribution of materials in the coastal environment.

• Korean Journal of Agricultural Science
• /
• v.23 no.1
• /
• pp.80-89
• /
• 1996

The expression and secretion of human lactoferrin (hLf) in Sacclnromyces diastaticus were performed. 1. For the secretion of hLf in yeast, recombinant plasmid pYEGLf was constructed using promoter, secretion signal sequence of glucoamylase I gene (STA1) and transcriptional terminator of GAL7 gene. 2. Each correct recombinant plasmid was selected by mini-preparation of plasmid DNA from E coli transformant and restriction enzyme digestion analysis. The selected plasmids, pYEGLf, were transformed into S. diastaticus YIY345 as a expression host, respectively. 3. Western blot analysis using rabbit anti-hLf was carried out to identify expressed hLf. Positive signals were shown in culture supernatant of pYEGLf transformant. 4. About $100{\mu}g-1mg$ of concentrated culture supernatant of positive clone were loaded on paper disc and tested for the antimicrobial activity against E coli. However, no activity was observed. We concluded that this fact results from low concentration of hLf secreted from yeast, compared with the fact that MIC of hLf is as high as $3mg/m{\ell}$. Therefore, the purification of secreted hLf may be require to investigate the antimicrobial activity. From this study, the feasibility of low-cost production of sufficient quantities of human lactofferin for nutritional and therapeutical applications were suggested.

• Clean Technology
• /
• v.18 no.3
• /
• pp.325-328
• /
• 2012

The condensation reaction of 9,9'-bis(4-hydroxyphenyl)fluorene with epichlorohydrin to prepare 9,9'-bis[4(glycidyloxy) phenyl]fluorene (2), an important building block for fluorene-containing epoxy polymers, has been studied. The reaction is found to be quite sensitive to several experimental conditions such as reaction temperature and time, added amount of epichlorohydrin, the presence of catalysts and the use of co-solvent. Several conditions for obtaining the best yield in the reaction are: the reaction temperature is below 373 K and the reaction time is shorter than 1.5 h, and the ammonium salts act as a catalyst. Also, the use of ternary solvent (toluene, DMSO, water) has been proved to be crucial to maintain the reaction temperature and for an easy purification. Thus, the reaction proceeds in an environment-friendly manner where the use of reactants and the production of chemical wastes is minimized.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.27 no.1
• /
• pp.116-125
• /
• 2024

The COVID-19 pandemic is not over despite the emergency use authorization as can see recent COVID-19 daily confirmed cases. The viruses are not only difficult to diagnose and treat due to random mutations, but also pose threat human being because they have the potential to be exploited as biochemical weapons by genetic manipulation. Therefore, it is inevitable to the rapid antibody-based therapeutic platform to quickly respond to future pandemics by new/re-emerging viruses. Although numerous researches have been conducted for the fast development of antibody-based therapeutics, it is sometimes hard to respond rapidly to new viruses because of complicated expression or purification processes for antibody production. In this study, a novel rapid antibody-based therapeutic platform using single B cell sorting method and mRNA-antibody. High immunogenicity was caused to produce antibodies in vivo through mRNA-antigen inoculation. Subsequently, antigen-specific antibody candidates were selected and obtained using isolation of B cells containing antibody at the single cell level. Using the antibody-based therapeutic platform system in this study, it was confirmed that novel antigen-specific antibodies could be obtained in about 40 days, and suggested that the possibility of rapid response to new variant viruses.