• Restorative Dentistry and Endodontics
• /
• v.45 no.3
• /
• pp.28.1-28.13
• /
• 2020

Objectives: To evaluate the outcome of in vitro studies comparing the effectiveness of QMix irrigant in removing the smear layer in the root canal system compared with other irrigants. Materials and Methods: The research question was developed by using Population, Intervention, Comparison, Outcome and Study design framework. Literature search was performed using 3 electronic databases PubMed, Scopus, and EBSCOhost until October 2019. Two reviewers were independently involved in the selection of the articles and data extraction process. Risk of bias of the studies was independently appraised using revised Cochrane Risk of Bias tool (RoB 2.0) based on 5 domains. Results: Thirteen studies fulfilled the selection criteria. The overall risk of bias was moderate. QMix was found to have better smear layer removal ability than mixture of tetracycline isonomer, an acid and a detergent (MTAD), sodium hypochlorite (NaOCl), and phytic acid. The efficacy was less effective than 7% maleic acid and 10% citric acid. No conclusive results could be drawn between QMix and 17% ethylenediaminetetraacetic acid due to conflicting results. QMix was more effective when used for 3 minutes than 1 minute. Conclusions: QMix has better smear layer removal ability compared to MTAD, NaOCl, Tubulicid Plus, and Phytic acid. In order to remove the smear layer more effectively with QMix, it is recommended to use it for a longer duration.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.4
• /
• pp.483-491
• /
• 2009

In vitro produced porcine embryos have potential application in reproductive biotechnology. However, their development potential has been very low. This study evaluated the in vitro developmental ability and quality of cloned and parthenogenetic porcine embryos having 2-4 cells or 5-8 cells on Day 2 of in vitro culture. Analysis of results showed that 2 to 4 cell embryos had higher ability to form blastocysts than 5 to 8 cell embryos (p<0.05). Blastocysts produced from culture of 2 to 4 cell embryos also contained higher cell numbers and had lower BAX:BCLxL transcript ratio than those produced from 5 to 8 cell embryos (p<0.05), thereby suggesting 2 to 4 cell embryos have higher development potential. Further investigation revealed that 5 to 8 cell embryos had higher incidence (100${\pm}$0.0%) of blastomeric fragmentation than 2 to 4 cell embryos (15.2${\pm}$5.5% for parthenogenetic and 27.7${\pm}$7.1% for cloned embryos). This suggests that low development potential of 5 to 8 cell embryos was associated with blastomeric fragmentation. In conclusion, we have shown that morphological selection of embryos based on cell number on Day 2 of in vitro culture could offer a practical and valuable non-invasive means to select good quality porcine embryos.

• Journal of the Korean Chemical Society
• /
• v.46 no.2
• /
• pp.157-163
• /
• 2002

To identify RNA motifs interacting with $tRNA^{Val}$, a SELEX(Systematic Evolution of Ligands by Exponential Enrichment) was applied. Random DNA library which contains a region of ran-domized 48-mer oligonucleotide flanked by conserved sequ ence primers was transcribed into RNA pool using T7 RNA polymerase and RNA aptamers were selected with $tRNA^{Val}$ -immobilized affinity column through 14 rounds of SELEX. Some of the resulting aptamers contained a consensus sequence similar to the sequence in the loop regions of three rRNAs; C43GAAC47 sequence of 5S rRNA, G1491AAGU1495, G1379UUCC1383 sequence of 16S rRNA and C1064UUAG1068, G2110UGUA2114, C2480GACGG2485, A2600CAGU2604 sequence of 23S rRNA. These results suggest that $tRNA^{Val}$ can interact with 5S rRNA, 16S rRNA and 23S rRNA with variety in ribosome.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.5 no.2
• /
• pp.84-91
• /
• 2000

Mycopasma contamination of tissue culture cells easily evades detection and, thus, represents a continous therat to cell biologists. In case where infected cell can not simply be replaced, attempts have to be made to eradicate mycoplacma from the tissue culture cells. A variety of anti-microbial agents have been shown to be toxic to mycoplasma strains ; however, cell associated mycoplasma are often protected from antibiotics at concentrations shown to be effective in vitro. Antibiotic concentrations high enough to be lethal to cell as sociated mycoplasmas frequently are also detrimentrations to the host cells, while moderately increased antibiotic levels tolerated by the host cells often lead to only temporary growth suppression and/or to the emergence of mycoplasma strains resistanct even to high concentrations of the antibiotis applied. Hare, a genetic approach for the elimination of mycoplasma from tissue culture cells that overcomes thens limitations is described. By expression of a selection marker conferring resistance to an otherwise toxic agent, Acholeplasma laidlawii infected BHK-21 cells used as the model system were enabled to temporarily tolerate antibiotic concentrations high enough to be lethal to cell associated mycopalsma while leaving the host cells unharmed. Upon successful mycoplasma eradicated, cultvation of the cured host cells in the absence of the selective agent yielded revertant cell clones that had regained susceptibillity to the toxic agent. Cressation of the selection marker expression was shown to result from the loss of the selection marker DNA, which is a consequence of the fact that the stable and permanent integration of foreign DNA in eucaryotic cell chrosomes is highly inefficient. Thus, the cells were cured from mycoplasma yet remained biochemically unaltered.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.11a
• /
• pp.135-140
• /
• 1994

Over past decades, numerous in vitro model has been developed to investigate drug metabolism. In the order of complexity we found the isolated perfused liver, hepatocytes in co-culture with epithelial cells, hepatocytes in suspension and in primary culture and subcellular hepatic microsomal fractions. Because they can be easily prepared from both animals (pharmacological and toxicological species) and humans (whole livers as well as biopsies obtained during surgery) hepatocytes in primary culture provide the most powerful model to better elucidate drug behavior at an early stage of preclinical development such as : 1. the characterization of main biotransformation reactions. 2. the identification of phase I and phase II isozymes involved in such reactions 3. the evaluation of interspecies differences allowing the selection of a second toxicological animal species more closely related to man on the basis of metabolic profiles 4. the detection of the inducing and/or inhibitory effects of a drug on metabolic enzymes, the prediction of drug interactions 5. the estimation of inter-individual variability in biotransformation reactions. The use of hepatocytes, and in particular those obstained from humans, at an early stage of drug development allows the obtention of more predictive preclinical data and a better knowledge of drug behavior in humans before the first administration of the drug in healthy volunteers.

• The Korean Journal of Mycology
• /
• v.51 no.4
• /
• pp.277-286
• /
• 2023

Tan spot, caused by Pyrenophora tritici-repentis, is a major foliar disease in wheat worldwide. In April 2021, tan spot symptoms were observed in a commercial wheat field in Suncheon, Jeonnam Province, Korea, with over 5% of the wheat leaves exhibiting symptoms. These symptoms included oval-shaped tan necrosis surrounded by a bright halo. The three representative isolates exhibited irregular mycelial growth on V8-potato dextrose agar and produced pseudothecia. Based on the concatenated sequence datasets of four multi-genes, including the internal transcribed spacer, large subunit ribosomal RNA, glyceraldehyde-3-phosphate dehydrogenase, and RNA polymerase II second-largest subunit genes, phylogenetic analysis revealed that these three isolates clustered in the same clade as P. tritici-repentis. Results of pathogenicity test indicated that the initial symptoms appeared 5 days post-inoculation (dpi), with typical tan spot symptoms developing at 7 dpi. The pathogen was successfully re-isolated from the symptomatic tissues, thus fulfilling Koch's postulates. Furthermore, we selected three fungicides that effectively inhibited the mycelial growth of P. tritici-repentis by more than 90% in vitro. To the best of our knowledge, this is the first report of tan spot disease in wheat in Korea.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.2
• /
• pp.75-82
• /
• 2013

Haploids are plants with a gametophytic number of chromosomes in their sporophytes. Androgenesis occurs from asymmetric division of pollen grains into generative cells and vegetative cells, followed by re-entry of the vegetative cell during S-phase, which causes microspores progress into G2/M transition in culture. One of the most interesting features of haploids is the possibility to produce doubled haploid (DH) individuals. Doubled haploidy is extremely useful to plant breeders because it enables shortened breeding periods and efficiency in selection of useful recessive agronomic traits. Doubled-haploid technology is not only applicable to breeding, but also to transformation programs of desired genes. In addition to practical breeding programs, DH lines provide useful materials of fundamental genetics including exploitation of QTLs and genes conferred with various agronomic traits by establishing DH populations. This paper provides historical overviews on androgenesis and describes several mechanisms associated with pollen embryogenesis, including mode of actions in pollen embryogenesis, mechanisms of chromosome doubling and factors affecting androgenesis. We also discuss recent progress in application of haploids to breeding, genes associated with in vitro response and drawbacks to anther culture for application of doubled haploids in crop breeding.

• Horticultural Science & Technology
• /
• v.29 no.1
• /
• pp.74-76
• /
• 2011

An interspecific hybrid lily cultivar 'Green Star' was bred in 2005 at the National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea. The crossing and in vitro embryo rescue was conducted between Lilium FA97-2 (L. ${\times}$ formolongi 'Silky White' ${\times}$ L. Asiatic 'Sunray') and L. Asiatic 'Bomi (Byeongga ${\times}$ Connecticut King)' by cut style pollination method (CSM) at Suwon in 2000. The first selection was done and was tentatively named as 'FA03-5' in 2003. After in vitro multiplication and bulbing production of 'FA03-5' line, growth and flowering characteristic tests were conducted from 2003 to 2005. The evaluation of characteristics and consumer preferences were surveyed at a lily flower show of NIHHS in 2005. 'Green Star' flowered in the middle of June and grew more than 120 cm stem in length. Flowers bloomed facing upward, unspotted in petals and greenish yellow (RHS, Y6D). 'Green Star' was male sterile. Year-round flowering can be done by storing the bulb under $-1.5^{\circ}C$ conditions. It was needed to control the Botrytis disease in wet season.

• BMB Reports
• /
• v.36 no.3
• /
• pp.275-281
• /
• 2003

An E1B-defective adenovirus, named r2/Ad carrying the neo expression cassette, was constructed by homologous recombination. The construction, selection (using neomycin as a selective marker), and propagation of the recombinant virus was performed in human embryonic kidney 293 cells (HEK 293). An in vitro study demonstrated that this recombinant virus has the ability to replicate in and lyse some p53-deficient human tumor cells such as human glioma tumor cells (U251) and human bladder cells (EJ), but not in some cells with functional p53, such as human adenocarcinoma cells (A549) and human fibroblast cells (MRC-5). Also, based on the cytopathic effect (CPE), it was demonstrated, under identical conditions, that the U251 cells were more sensitive to r2/Ad replication than the EJ cells. In this paper, we report that r2/Ad could be very useful in studying the in vitro selective replication of E1B-defective adenovirus and has great potential in cancer gene therapy.

• Clinical and Experimental Reproductive Medicine
• /
• v.41 no.2
• /
• pp.41-46
• /
• 2014

IVM refers to the maturation of immature oocytes in culture after their recovery from small antral follicles at the stage prior to selection and dominance. IVM requires little or no FSH in vivo and has been proposed as an alternative to conventional IVF, since it reduces the primary adverse effects caused by controlled ovarian stimulation, including the ovarian hyperstimulation syndrome. Moreover, IVM is a promising option for cases for which no standard protocol is suitable, such as FSH resistance, contraindications for ovarian stimulatory drugs, and the need for urgent fertility preservation. Recently, IVM has been used in women with regular cycles and normal ovaries. However, the pregnancy rate following IVM is suboptimal compared with that of conventional IVF, indicating that further studies to optimize the protocol and the culture conditions are warranted.