• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.79-79
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• 2003

Embryonic stem cells are capable of differentiating into a variety of cell lineages. However, the ultimate results of differentiation in vitro greatly depend on the duration of treatment and kinds of differentiating inducers added. In order to investigate the efficiencies of various differentiation inducers and the methods of treatment, we examined differentiation patterns of human embryonic stem cell (hESC, MB03) according to several different protocols. Exp. I) Upon differentiation using retinoic acid and ascorbic acid (RA/AA), embryoid bodies (EB, for 4days) derived from hESC was exposed to Rh (10$^{-6}$ M) and AA (50 mM) for 4 days, and were allowed to differentiate in N2 medium for 7, 14, 21, or 28 days. Exp. II) When bFGF was used, neuronal precursor cells were selected for 8 days in N2 medium after EB formation. After selection, cells were expanded at the presence of bFGF (20 ng/ml) for another 6 days followed by a final differentiation in N2 medium for 7, 14, 21 or 28 days. Exp. III) In addition, to examine the effects of neurotrophic factors in the production of mature neurons, groups of cells were exposed to either BDNF (5 ng/ml) or TGF-$\alpha$(10 ng/ml) during the 28 days of final differentiation. Differentiation patterns of RA/AA or bFGF treated groups were very similar; approximately 82% and 83% of the cells, respectively, were positive for anti-NF200 antibody, while it was about 10% and 11%, respectively, for anti-NF160 antibody in 28 days in N2 medium. Alsor, cells expressing TH were as low as 5%, while the cells doubled when matured at the presence of either BDNF or TGF-$\alpha$. Cells immunoreactive to anti-GAD antibody were approximately 20%. These results suggest that a maturation step rather than differentiation induction step, which is formation of EB, effects more decisively to the ultimate differentiation pattern.

• 한국자원식물학회지
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• 제36권6호
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• pp.571-579
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• 2023

In this study, cryopreservation by droplet-vitrification was applied to pear (Pyrus spp.) germplasm. We focused on the development and assessment of various strategies for the selection of suitable tissue, osmoprotection, and dehydration. We also evaluated post-thaw recovery of cryopreserved explants by droplet-vitrification. Preferentially, we tested the effects of preculture and loading treatments to determine which tissues were more suitable, either the apical shoot tips or the axillary buds. Apical shoot tips showed the better regrowth rate than in vitro axillary buds. The most effective techniques for cryopreservation were as follows. Shoots from in vitro seedlings which had been cultured for about 5-6 weeks were cold-hardened at 4℃ for one week, excised shoot tips were precultured on liquid MS medium including 0.3 M sucrose for 31 hours and 0.7 M sucrose for 17 hours, osmoprotected in loading solution (LS) for 40 min, and then cryoprotected in dehydration solution (PVS3) for 90 min. In addition, we found that regrowth rates of explants on regrowth medium after exposure to liquid nitrogen (LN) were higher than those on MS medium. Results indicated that the highest regrowth percentage was 95.6% for 'Bartlett' cultivar and 68.9% for 'BaeYun No.3' cultivar. Consequently, apical shoot tips of two pear cultivars, 'Bartlett' (P. communis) and 'BaeYun No.3' (P. pyrifolia), were successfully cryopreserved by droplet-vitrification. Results of this study show that the enhanced droplet-vitrification method described in the present study could be used as an effective means for long-term storage of pear genetic resources.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3001-3003
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• 2013

Objective: Spleen tyrosine kinase (Syk) is closely related to tumor invasion and metastasis, and has been shown to have potential inhibitory effects in tumors. In this study, we constructed a eukaryotic expression vector for Syk and analyzed its effects on invasive ability of the A549 non-small cell lung cancer cell line in vitro. Methods: A fragment of Syk was obtained by RT-PCR from human lung cancer cells and cloned into the expression vector pLNCXSyk. After restriction endonuclease digestion, PCR and DNA sequencing confirmation, the recombinant Syk expression plasmid was transfected into A549 human lung cancer cells using lipofectamine protocols. After selection, the cells stably expressed Syk. Detection of Syk expression of the cells by RT-PCR, and invasive ability were examined. Results: The eukaryotic expression plamid pLNCXSyk was constructed and expressed stably in the A549 human lung cancer cells. The RT-PCR results showed that Syk mRNA expression was upregulated significantly (P<0.05). Lower invasion through a basal membrane were apparent after transfection (P<0.05). Conclusions: A eukaryotic expression plasmid to cause Syk expression in lung cancer cells can obviously inhibit their invasive ability in vitro.

• 한국축산시설환경학회지
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• 제19권1호
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• pp.63-68
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• 2013

In vitro culture and radiation techniques were used for obtaining mutants tin tall fescue. Endophyte free and friendly tall fescue cultivars Kentucky-31 and Jesup were used for induction of genetic variability through in-vitro mutagenesis. Mature seeds was used for callus induction on 6 mg/L 2,4-D. Actively growing and compact callus was treated with three different doses of gamma rays (10 Gy, 30 Gy and 50 Gy). Maximum proliferation and plantlets regeneration growth was observed in control and minimum at 10 Gy. Furthermore, the maximum number of tiller in the irradiated population was observed in 10 Gy. The treatments 30 Gy and 50 Gy exhibited negative impact on the tillering potential of the tall fescue plant. The object of this study was to develop protocols for mutation breeding in tall fescue through radiation techniques.

• Asian-Australasian Journal of Animal Sciences
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• 제26권12호
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• pp.1698-1707
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• 2013

Optimization of the dietary formulation is the most effective way to reduce methane. Nineteen feed ingredients (brans, vegetable proteins, and grains) were evaluated for their potential to generate methane and change methanogen diversity using an in vitro ruminal fermentation technique. Feed formulations categorized into high, medium and low production based on methane production of each ingredient were then subjected to in vitro fermentation to determine the real methane production and their effects on digestibility. Methanogen diversity among low, medium and high-methane producing groups was analyzed by PCR-DGGE. The highest methane production was observed in Korean wheat bran, soybean and perilla meals, and wheat and maize of brans, vegetable protein and cereal groups, respectively. On the other hand, corn bran, cotton seed meal and barley led to the lowest production in the same groups. Nine bacteria and 18 methanogen 16s rDNA PCR-DGGE dominant bands were identified with 83% to 99% and 92% to 100% similarity, respectively. Overall, the results of this study showed that methane emissions from ruminants can be mitigated through proper selection of feed ingredients to be used in the formulation of diets.

• Current Research on Agriculture and Life Sciences
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• 제6권
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• pp.75-85
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• 1988

포푸라(양황철)의 기내배양(器內培養)에서 대량증식(大量增殖)한 유전적(遺傳的)으로 균일(均一)한 시료(試料)를 이용(利用), NaCl내성(耐性)을 검정(檢定)한 결과(結果) 50mM이 생육한계(生育限界)임을 밝혀냈다. 엽표피(葉表皮)를 침(針)으로 뚫어 MS 기본배지(基本培地)에 Auxin과 Cytokinin의 효과(效果)를 검정(檢定)한 결과(結果) Cytokinin에서는 많은 개체(個體)가 발생(發生)하였으며 특(特)히 BAP $0.8mg/{\ell}$에서는 127.6개의 많은 개체(個體)가 발생(發生)하였다. NaCl 내성개체(耐性個體) 선발(選拔)을 위(爲)해 같은 배지(培地)에 NaCl 10mM부터 100mM까지 10단계로 처리(處理)하여 침(針)으로 자극한 시료(試料)를 접종(接種)한 결과(結果) 50mM 이상(以上)에서 13.7~15.7개의 여러가지 개체(個體)를 얻었다. 특(特)히 90mM에서 10.7개 100mM에서도 8.3개의 개체(個體)를 얻었다. 비선발(非選拔) 개체(個體)는 50mM 이상(以上)의 NaCl 첨가(添加)배지에서 생장(生長)이 완전(完全)히 중지(中止)된 반면(反面)에 기내선발개체(器內選拔個體)는 고농도(高濃度) NaCl의 계대배양에서도 생장(生長)를 계속하였다. 이상(以上)의 결과(結果)에서 임목(林木)에 있어서도 기내배양법(器內培養法)를 이용(利用)하여 내성(耐性) 개체(個體)를 선발(選拔)할 수 있는 가능성(可能性)을 추정(推定)할 수 있었다.

• 한국약용작물학회지
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• 제20권1호
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• pp.47-53
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• 2012

This study was conducted to examine effects of plant growth regulators and light resources on the formation of multiple shoot and plant regeneration of Hovenia dulcis var. koreana Nakai. Stem and shoot tip were cultured on MS medium or WPM supplemented with various plant growth regulators. At the single treatment, the highest shoot formation was obtained when stem explants were cultured on WPM supplemented with kinetin $1.0mg{\cdot}L^{-1}$. MS medium containing NAA 0.1 and TDZ $0.1mg{\cdot}L^{-1}$ gave the best results for shoot induction rate and shoot growth in combination treatments. Of the BAP and kinetin tested, BAP $0.5mg{\cdot}L^{-1}$ on WPM was found to be more effective for shoot growth from shoot tip. Under white fluorescent light treatment, shoot growth was much higher than blue, red LED treatments. Root induction from in vitro growth of plantlet was the best on WPM supplemented with $1.0mg{\cdot}L^{-1}$ IBA. The results suggest that selection of plant growth regulators and light resources could be important factor to achieve an efficient in vitro growth.

• International Journal of Stem Cells
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• 제16권4호
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• pp.438-447
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• 2023

Recently, ex-vivo gene therapy has emerged as a promising approach to enhance the therapeutic potential of mesenchymal stem cells (MSCs) by introducing functional genes in vitro. Here, we explored the need of using selection markers to increase the gene delivery efficiency and evaluated the potential risks associated with their use in the manufacturing process. We used MSCs/CD that carry the cytosine deaminase gene (CD) as a therapeutic gene and a puromycin resistance gene (PuroR) as a selection marker. We evaluated the correlation between the therapeutic efficacy and the purity of therapeutic MSCs/CD by examining their anti-cancer effect on co-cultured U87/GFP cells. To simulate in vivo horizontal transfer of the PuroR gene in vivo, we generated a puromycin-resistant E. coli (E. coli/PuroR) by introducing the PuroR gene and assessed its responsiveness to various antibiotics. We found that the anti-cancer effect of MSCs/CD was directly proportional to their purity, suggesting the crucial role of the PuroR gene in eliminating impure unmodified MSCs and enhancing the purity of MSCs/CD during the manufacturing process. Additionally, we found that clinically available antibiotics were effective in inhibiting the growth of hypothetical microorganism, E. coli/PuroR. In summary, our study highlights the potential benefits of using the PuroR gene as a selection marker to enhance the purity and efficacy of therapeutic cells in MSC-based gene therapy. Furthermore, our study suggests that the potential risk of horizontal transfer of antibiotics resistance genes in vivo can be effectively managed by clinically available antibiotics.

• 한국약용작물학회지
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• 제11권4호
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• pp.289-297
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• 2003

Using Agrobacterium-me야ated transformation method the auxin-regulated cotton GST (Gh-5) constructs were used to transform Rehmannia glutinosa L. The PCR analysis was conducted to verify transgenicity. Based on the PCR analysis, there was verified that the 988 bp DNA band had showed in transgenic plant genomes in PCR anaJysis using Gh5-1 and Gh5-2 primers. The effects of cocultivation with Agrobacterium tumefaciens, regeneration and selection conditions on the transformation efficiency of Chinese foxglove (Rehmannia glutinosa L.) were investigated. Factors such as cocultivation period, use of acetosyringone, postcultivation in darkness, and different kanamycin concentrations for selection were assessed. In vitro regeneration, the number of leaves, shoot lengths and numbers on MS medium were superior to on B5 and WPM medium, and the shoot formation rate was highest level of 95% in cultured base part containing leaf stalk. Addition of acetosyringone at concentration of $200{\mu}M$ to cocultivation medium and 3-day of cocultivation improved transformation frequencies. Exposure of explants to darkness for 4 weeks on selection medium resulted in further increased the regeneration frequency of transgenic shoots. In PCR analysis, the amplified fragments of Gh5 gene were detected (988 bp), and GST-expressing transgenic R. glutinosa L. plants had approximately three-fold higher activity in leaf extracts compared with control plant.

• 농업과학연구
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• 제43권5호
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• pp.802-809
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• 2016

The objective of this study was to evaluate the nutritional value of commercial compound feeds for late finishing Hanwoo steers using detailed chemical analysis and an in vitro rumen fermentation trial. A total of 4 different feeds were selected and used to conduct a chemical analysis for their nutrient contents. The largest variation in nutrients contents among experimental feeds was found in ether extract and the smallest one was found in total digestible nutrients. Commercial feeds C and D had a higher energy value than the others. Even if C and D had a similar feed energy value, the components used to increase energy differed between them (non-fiber carbohydrate [NFC] for C; ether extract for D). In the in vitro trial, no significant difference was observed in dry matter in vitro digestibility and gas production between treatments. However, the highest ammonia concentration (p < 0.05) was observed in C and D feeds. The low acetate to propionate ratio observed in C feeds (p < 0.01) suggested that this feed had high starch based carbohydrates that NFC degrading bacteria used to produce more propionate. It is important to provide nutritional information to farmers so that they can select the appropriate commercial feeds to suit their own feeding strategies. This study might give supporting information to farmers for a more educated, and better, selection of feeds. Further in vivo studies should be conducted to evaluate the effects of different commercial feeds on growth performances in late finishing Hanwoo steers.