• Korean Journal of Microbiology
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• v.29 no.1
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• pp.16-24
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• 1991

The yeast gene THR1 encodes the homoserine kinase (EC 2.7.1.39: HKase) which catalyses the first step of the threonine specific arm at the end of the common pathway for methionine and threonine biosynthesis. A recombinant plasmid pMC3 (12.6 kilobase pairs, vector YCp50) has been cloned into E. coli HB101 from a yeast genomic library through its complementing activity of a thr1 mutation in a yeast recipient strain M39-1D. When subcloned into pMC32 (8.6kbp, vector YRp7) and pMC35 (8.3 kbp, vector YIp5), the HindIII fragment (2.7 kbp) of pMC3 insery was positive in the thrI complementing activity in both yeast and E. coli auxotrophic strains. The linearized pMC35 was introduced into the original recipient yeast strain and the mitotically stable chromosomal integrant was identified among the transformants. Through the tetrad analysis, the integration site of the pMC35 was localized to the region of THR1 structural gene at an expected genetic distance of approximately 11.1 cM from the ARG4 locus on the right arm of the yeast chromosome VIII. When episomically introduced into the auxotrophic cells and cultured in Thr omission liquid medium, the cloned gene overexpressed the HKase in the order of thirteen to fifteenfold, as compared with a wildtype. HKase levels are repressed by addition of threonine at the amount of 300 mg/l and 1, 190 mg/l for pMC32 and pMC3, respectively. Data from genetic analysis and HKase response thus support that the cloned HindIII yeast DNA fragment contains the yeast thr1 structural gene, along with necessary regulatory components for control of its proper expression.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1223-1232
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• 2017

Cordyceps militaris, a member of Ascomycota, a mushroom referred to as caterpillar Dong-chung-ha-cho, is commercially valuable because of its high content of bioactive substances, including cordycepin, and its potential for artificial cultivation. Cordycepin (3'-deoxyadenosine) is highly associated with the pharmacological effects of C. militaris. C. militaris is heterothallic in that two mating-type loci, idiomorph MAT1-1 and MAT1-2, exist discretely in two different spores. In this study, nine C. militaris strains were mated with each other to prepare newly bred strains that produced a larger amount of cordycepin than the parent strains. Nine strains of C. militaris were identified by comparing the internal transcribed spacer sequence, and a total of 12 single spores were isolated from the nine strains of C. militaris. After the MAT idiomorph was confirmed by PCR, 36 mating combinations were performed with six single spores with MAT1-1 and the others with MAT1-2. Eight mating combinations were successfully mated, producing stroma with perithecia. Cordycepin content analysis of all strains by high-performance liquid chromatography revealed that the KASP4-bred strain produced the maximum cordycepin among all strains, regardless of the medium and stroma parts. Finally, universal rice primer-PCR was performed to demonstrate that the bred strains were genetically different from the parental strains and new C. militaris strains. These results may be related to the recombination of genes during mating. The newly produced strains can be used to meet the industrial demand for cordycepin. In addition, breeding through mating suggests the possibility of producing numerous cordycepin-producing C. militaris strains.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.379-385
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• 2017

In this study, white ginseng was used as the raw material, which was fermented with Paecilomyces hepiali through solid culture medium, to produce ginsenosides with modified chemical composition. The characteristic chemical markers of the products thus produced were investigated using rapid resolution liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (RRLC-QTOF-MS). Chemical profiling data were obtained, which were then subjected to multivariate statistical analysis for the systematic comparison of active ingredients in white ginseng and fermented ginseng to understand the beneficial properties of ginsenoside metabolites. In addition, the effects of these components on biological activity were investigated to understand the improvements in the phagocytic function of macrophages in zebrafish. According to the established RRLC-QTOF-MS chemical profiling, the contents in ginsenosides of high molecular weight, especially malonylated protopanaxadiol ginsenosides, were slightly reduced due to the fermentation, which were hydrolyzed into rare and minor ginsenosides. Moreover, the facilitation of macrophage phagocytic function in zebrafish following treatment with different ginseng extracts confirmed that the fermented ginseng is superior to white ginseng. Our results prove that there is a profound change in chemical constituents of ginsenosides during the fermentation process, which has a significant effect on the biological activity of these compounds.

• KSBB Journal
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• v.31 no.1
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• pp.73-78
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• 2016

The aim of this study attempted to verify the possibility of bioethanol production using wasted medium density fiberboard (wMDF). In order to produce bioethanol from wood cellulosic materials must be carried out the process of pretreatment, saccharification, fermentation and distillation. First, the wMDF was pretreated using sodium chlorite and pretreated wMDF was prepared to 8% slurry and then slurry was saccharified with the commercial enzyme (Cellic CTec3). The fermentable sugar and pH of saccharified substrate were about 5.5% glucose and 4.4, respectively. Herein we compared the results of ethanol yield according to the nutrients added or without addition to increase ethanol yield. Ethanol fermentation was finished in about 24 hours, but it was delayed in experimental group without nutrients. Ethanol content and fermentation ratio of the final fermented mash prepared by utilizing jar fermenter was 25.40 g/L and 86.64%, respectively. At this time, the maximum ethanol productivity was confirmed as 1.78 g/Lh (ethanol content 21.38 g/L, 12 h), and the overall ethanol productivity was 1.05 g/Lh (ethanol content 25.27 g/L, 24 h). Using fermented liquid we could produced bioethanol 95.37% by continuous distillator packed with copper element in laboratory scale. These results show that wMDF has a potential valuable for bioethanol production.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.2
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• pp.117-126
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• 2022

Objective: This study examined whether the addition of triple antioxidants (3A)-10 µM acetyl-L-carnitine, 10 µM N-acetyl-L-cysteine, and 5 µM α-lipoic acid-in freezing-thawing medium during human sperm cryopreservation using the sucrose vitrification (SuV) and liquid nitrogen vapor (Vapor) techniques could improve post-thaw survival of spermatozoa. Methods: We analyzed 30 samples from healthy human sperm donors. Each sample was allocated into one of five groups: fresh control, SuV, SuV+3A, Vapor, and Vapor+3A. The sperm motility, morphology, viability, intracellular and extracellular reactive oxygen species (ROS) levels, and sperm DNA fragmentation (SDF) were evaluated. Results: The cryopreserved spermatozoa had significantly reduced percentages of motility (p<0.05) and viability (p<0.05). Antioxidant supplementation non-significantly improved these parameters (p>0.05). No significant differences were found in sperm morphology between the fresh and frozen-thawed groups (p>0.05). After freezing, the extracellular ROS levels in the frozen-thawed groups were significantly higher (p<0.05) than in the fresh group. However, we did not find any differences in intracellular ROS parameters among these groups (p>0.05). The SDF was higher in the SuV and Vapor groups than in the fresh group, but without statistical significance (p=0.075 and p=0.077, respectively). Conclusion: Cryopreservation had detrimental effects on sperm motility, viability, and extracellular ROS levels, without changing the morphology or intracellular ROS levels. Antioxidant supplementation was slightly effective in preventing SDF in frozen-thawed spermatozoa.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.331-338
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• 2022

Sunflower (Helianthus annuus L.) protoplasts were isolated from seven-day-old etiolated hypocotyls of 10 A line and four-week-old fully expanded young leaves of PI 441983 line in vitro seedlings using an enzymatic method. Purified protoplasts were collected by filtration and floatation in sucrose solution. Semi-solid protoplast culture was performed using the L4 regeneration protocol with various culture media and plating densities to achieve the highest efficiencies for protoplast culture of hypocotyl and mesophyll protoplasts of 10 A and PI 441983 lines, respectively. The concentrations in liquid L'4M medium and different plating densities were evaluated in two types of cytokinins, the adenine-type 6-benzyladenine (BA) and the phenylurea-type thidiazuron (TDZ). The highest colony formation was achieved in both sunflower lines when 0.5 mgL^-1 BA and 0.5 mgL^-1 TDZ were applied with a high plating density (3 × 10⁵ protoplasts mL^-1). These conditions led to 38.45% and 39.40% colony formation for hypocotyl protoplasts of the 10 A line and mesophyll protoplasts of the PI 441983 line, respectively. Moreover, many hypocotyl protoplast-derived colonies developed into micro-calli. In addition, superior development of both sunflower protoplasts was observed with all plating densities when BA was used in combination with TDZ. This finding will be applicable to future sunflower hybrid production via somatic hybridization.

• Composites Research
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• v.36 no.6
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• pp.416-421
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• 2023

Multifunctional composite materials capable of both load-carrying and energy functions are promising innovative candidates for the advancement of contemporary technologies owing to their relative feasibility, cost-effectiveness, and optimized performance. Carbon fiber (CF)-based structural batteries utilize the graphitic inherent structure to enable the employment of carbon fibers as electrodes, current collectors, and reinforcement, while the matrix system is an ion-conduction and load transfer medium. Although it is possible to enhance performance through the modification of constituents, there remains a need for a systematic design methodology scheme to streamline the commercialization of structural batteries. In this work, a bi-phasic epoxy-based ionic liquid (IL) modified structural battery electrolyte (SBE) was developed via thermally initiated phase separation. The polymer's morphological, mechanical, and electrochemical characteristics were studied. In addition, the interfacial shear strength (IFSS) between CF/SBE was investigated via microdroplet tests. The results accentuated the significance of considering IFSS and matrix plasticity in designing composite structural batteries. This approach is expected to lay the foundation for realizing smart structures with optimized performance while minimizing the need for extensive trial and error, by paving the way for a streamlined computational design scheme in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.545-549
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• 2001

To develop a natural antibacterial agent for fish bacterial diseases, antibacterial activity, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and bactericidal effect of cinnamon bark extract were examined against fish pathogenic bacteria. The antimicrobial effect of the extract to the fish diet was also estimated, Cinnamon bark extract showed the broad spectrum of antibacterial activity against fish pathogenic bacteria, especially, it had strong activity against Streptococcus iniae, Edwardsiella tarda and Listonella anguillarum. Its MIC was $75.8\sim189.6{\mu}g/mL$ against Cram positive bacteria, and $75.8\sim113.8{\mu}g/mL$ against Gram negative bacteria in liquid medium, It was found to show stronger bactericidal action against Gram negative bacteria than Cram positive bacteria. According to increasing concentrations of the extract, it resulted in a proportional reduction of viable cell counts of both S. iniae and L. anguillarum. The former was not detected by addition of $189.6{\mu}g/mL$ after 12 hours incubation and the latter by addition of $151.6{\mu}g/mL$ after 24 hours incubation, respectively. It was reasonable that fish diet was soaked in cinnamon bark extract for ten minutes. The relationship formula between the weight of fish diet and the extract absorbed to fish diet was Y=7.2726X+4.5083 ($R^2=0.9998$). The fish diet soaked in the extract inhibited the growth of all strains used in this study. Its antibacterial activity was stable at the range from $10^{\circ}C\;to\;35^{\circ}C$ during the storage period of 28 days. When the diet soaked in the extract was incubated in liquid medium at $35^{\circ}C$, it inhibited the growth of microorganisms inhabited in the diet.

• Research in Plant Disease
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• v.20 no.2
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• pp.112-118
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• 2014

A liquid bio-formulation containing chitinolytic bacteria, chitin and their products was assessed for its potential biological control against root-knot nematodes on cucumber. The bio-formulation was prepared by cultures of three chitinolytic bacteria, Chromobacterium sp. strain C-61, Lysobacter engymogenes and Serratia plymuthica in minimal medium supplemented with chitin. Under pot conditions, the bio-formulation showed better growth of cucumber plants, and less root galls and population density of Meloidogyne spp. than control media without the bio-formulation. In a greenhouse, 75-fold diluted bio-formulations were treated instead of water around cucumber plants through hoses for drip irrigation six times at 5-day intervals from the transplanting date. After 30 and 60 days, the treatment provided about 7% and 10% enhancement in the plant height and about 78% and 69% reduction in population density of Meloidogyne spp. in the rhizosphere, respectively. In addition, the experiments showed that the control effects occurred only in the soils contacted with the bio-formulation. Undiluted bio-formulations were drenched three times at 10-day intervals around cucumber plants severely infested with Meloidogyne spp. The treatment showed about 37% plant enhancement without dead plants compared with 37% death in the untreated control, and about 82% nematode reduction. These results suggest that the bio-formulation can be practically used to control the root-knot nematode on cucumber.

• Journal of Mushroom
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• v.12 no.1
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• pp.17-23
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• 2014

pH of oriental medicine sludge was 5.3, which was similar to 5.2 of the main ingredient, corncob. Its sugar content, however, was 4.8 mg/g, which was 2.5 times higher than concorb's 1.9 mg/g. According to the addition content analysis of oriental medicine sludge by using blood agar plate, the experimental group showed much more robust growth than the control group. 10% of oriental medicine sludge was added to corncob and pine tree sawdust for test-tube culture. Then they were cultivated at $25^{\circ}C$ for 6 days after inoculating Flammulina velutipes liquid spawn. The control group and experimental group showed 2.2~3.4 and 5.8~6.4 cm hypae growths respectively. At the field test for 10% herbal medicine refuse, mushroom yield dropped by 5% compared to the control group. However, it had distinctively lower number of deformity and the 2nd grade products. An economic analysis was conducted based on the cultivation facility that produces 160,000 mushrooms per day. The analysis demonstrated that the facility can save 50,000,000 won in the starting year and 130,000,000 won in the following years from the unit cost of production excluding labour and operation cost.