• Plant Biotechnology Reports
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• 제5권2호
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• pp.187-195
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• 2011

The gesneriaceous perennial plant Titanotrichum oldhamii has beautiful foliage and attractive bright yellow flowers. However, breeding of T. oldhamii by conventional sexual hybridization may be difficult because sexual reproduction of this species is very rare. In the present study, plant regeneration systems via both direct and indirect formation of adventitious shoots from leaf explants were established as the first step toward breeding T. oldhamii by using biotechnological techniques. Adventitious shoots were formed efficiently on medium containing $0.1mg\;l^{-1}$ benzyladenine. Histological observation showed that shoot formation on this medium occurred directly from leaf epidermal cells without callus formation. On the other hand, leaf explants formed calluses on medium containing $0.1mg\;l^{-1}$ 2,4-dichlorophenoxyacetic acid. The calluses could be maintained by monthly subculturing to fresh medium of the same composition. When the calluses were transferred to plant growth regulator-free medium, they formed adventitious shoots. Directly and indirectly formed shoots rooted well on medium containing $0.1mg\;l^{-1}$ indole-3-butyric acid. Plantlets thus obtained were successfully acclimatized and grew vigorously in the greenhouse. Flow cytometry analysis indicated that no variation in the ploidy level was observed in plants regenerated via direct shoot formation, whereas chromosome doubling occurred in several plants regenerated via indirect shoot formation. Regenerated plants with the same ploidy level as the mother plants showed almost the same phenotype as the mother plants, whereas chromosome-doubled plants showed apparent morphological alterations: they had small and crispate flowers, and round and deep green leaves.

• 한국미생물·생명공학회지
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• 제18권5호
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• pp.460-465
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• 1990

Asp.wentii와 Asp.nidulans의 원형질체 재생은 2-DG가 30$\mu g$/ml 첨가된 포자현탁액을 4시간 전배양 할 때 적당하였고 ergosterol, myoniositol, casamino acid, BSA가 함유된 CBE 재생용 배지에서 효과적이었으며, 30 이상 재생률을 나타내었다. 원형질체 융합은 10mM $CaCl_2$가 함유된 pH7.5의 30PEG 4000으로$37^{\circ}C$ 에서 10분간 처리했을 때 가장 양호하였으며, 융합빈도는 $8.2\times 10^{-4}$을 나타내었다. 가장 우수한 융합주인 FWN-56은 CMCase, avicelase, $\beta$-glucosidase 및 xylanase를 동시에 분비하였으며 친주에 비하여 활성이 2.3배, 1.5배, 1.8배, 2.5배 각각 증가하였고, 또한 MM에 4중 이상 보관 후의 segregant율이 1 이내였으므로 유전적 안정성은 높았으며, 분생포자 DNA함량은 1.4-1.6배였다. 또한 핵의 크기도 친주에 비하여 큰 것으로 보아 융합주임을 확인하였다.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.6-13
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• 1992

유산균주의 균주개량방법의 일환으로 protoplast fusion 방법을 사용하여 lincomycin에 내성을 나타내는 Lactobacillus casei KCTC 1121과 rifampicin에 내성을 나타내는 Lactobacillus delbruckii JK-414의 protoplast 형성과 재생, 융합에 대한 조건 및 융합주의 생리학적 성질 등을 검토하였다. Lactobacillus case와 Lactobacillus delbrueckii JK-414는 삼투압 안정제로 sucrose가 함유된 protoplast forming buffer에서 5$\mu g$/ml의 mutanolysin 으로 $42^{\circ}C$, 15분간 처리 했을 때 protoplast 형성율이 높게 나타났다.

• Journal of Plant Biotechnology
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• 제5권1호
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• pp.43-49
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• 2003

Resistant cell lines to azetidine-2-carboxylic acid (AZCA) were selected through rice embryo culture after mutagenic treatment of callus irradiated with 30,50,70,90 and 120 Gy. The optimum AZCA concentration for the selection of resistant cell lines was 3 or 4 mM AZCA considering $LD_{50}$ and the fresh weight of callus. Survival rate of the AZCA resistant callus showed remarkable increase in the callus irradiated with 50 and 70 Gy. Regeneration rate of the AZCA resistant callus was much lower on the whole. Ninety and 120 Gy increased the regeneration rate for calli selected from 3 and 4 mM AZCA, respectively. Based on fresh weight, survival rate and regeneration for selection of the AZCA resistant cell line, 50-90 Gy was considered as the optimum range of gamma irradiation. Irradiated calli selected from AZCA were more tolerant to NaCl than those from non-irradiated calli. It suggests that elevated resistance to osmotic stress resulted from mutagenic treatment. The level of free proline content in the AZCA resistant cell line was increased up to 3.5 times compared with that in the control. Proline content in the regenerant derived from the AZCA resistant cell line also increased to 1.7 times that from the control plants regenerated from callus grown in AZCA free medium. Selection of proline overproducing cell lines by in vitro mutagenesis was successful and seems to be useful for improvement of stress tolerance in this crop.

• Journal of Plant Biotechnology
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• 제6권3호
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• pp.171-179
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• 2004

Hormonal requirements inducing different regeneration pathways with particular emphasis on somatic embryo-genesis in Alhagi graecorum were studied. While combination of 0.5 $\mu{M}$ 2,4-dichlorophenoxyacetic acid (2,4-D), 2.5 $\mu{M}$ 6-benzylaminopurine (BAP) and 5 $\mu{M}$ 1-naphthaleneacetic acid (NAA) in MS medium induced callus formation and callus maintenance from internodal explants, each alone or in combination with other induced distinct regeneration pathway. Adventitious bud formation was induced on MS medium supplemented with 2.5 $\mu{M}$ BAP. It was improved when 2.5 $\mu{M}$ BAP was used in combination with 5 $\mu{M}$ NAA. MS medium containing 0.5 $\mu{M}$ 2,4-D or 5 $\mu{M}$ NAA induced the formation of abnormal direct somatic embryos. While increase of 2,4-D concentration (1.125-9) resulted in the formation of viable embryogenic mass, increase of NAA did not change its effect. NAA should be used in combination with 2,4-D even at low concentration (0.5 $\mu{M}$) to form embryogenic mass. In A. gaecorum, the role of 2,4-D as trigger of somatic embryogenesis and BAP as trigger of adventitious bud formation was deduced, but for maximum yield certain auxin-cytokinin ratio should be applied. Embryogenic masses characterized by high water content, low peroxidase activity, and low number of peroxidase and glutamate oxaloacetate transaminase bands in comparison with calli obtained under conditions stimulating adventitious bud formation. The resulted differential gene expression, which could be detected by native-PAGE patterns, could be used as marker for organogenic pathway in A. graecorum.

• Journal of Periodontal and Implant Science
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• 제39권2호
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• pp.167-176
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• 2009

Purpose: The purpose of this study is to histologically and histomorphometrically evaluate the effect of PLGA on bone regeneration compared with bone graft material. Methods: The experimental study was conducted in 10 rabbits with 2 different healing periods of 2 and 4 weeks. Following surgical exposure of the calvarium, 4 circular bone defects with a diameter of 4.6mm were formed. Rabbits were divided into control group, test groups I, and II. 10 defects assigned to the test group Ⅰ were grafted with Nu-oss and other 10 defects assigned to the test group II were grafted with PLGA. The rest of the defects were in the negative control group. At 2nd and 4th week after surgery, 10 rabbits were sacrificed through intracardiac perfusion and then specimens were obtained. Histological analysis was performed following staining with trichorme and transversal sectioning of the calvarial bone. Results: A group which used PLGA showed tissue reactions characterized by severe inflammation, rather than distinctive new bone formation. Conclusions: The present experimental investigations have failed to prove any beneficial effects of PLGA. PLGA used in this study exhibited foreign body reactions and a less favorable pattern of new bone formation in comparison to control group. Conclusion: PLGA did not function as scaffold. Further investigations of many types of micro PLGA that could improve its potential in GBR procedures are needed.

• Journal of Periodontal and Implant Science
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• 제40권2호
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• pp.69-75
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• 2010

Purpose: Implant survival rates using a bone-added osteotome sinus floor elevation (BAOSFE) procedure with simultaneous placement of a non-submerged sand blasted with large grit and acid etched (SLA) implant are well documented at sites where native bone height is less than 5 mm. This study evaluated the clinical results of non-submerged SLA Straumann implants placed at the time of the BAOSFE procedure at sites where native bone height was less than 4 mm. Changes in graft height after the BAOSFE procedure were also assessed using radiographs for 5 years after the implant procedure. Methods: The BAOSFE procedure was performed on 4 patients with atrophic posterior maxillas with simultaneous placement of 7 non-submerged SLA implants. At least 7 standardized radiographs were obtained from each patient as follows: before surgery, immediately after implant placement, 6 months after surgery, every year for the next 3 years, and after more than 5 years had passed. Clinical and radiographic examinations were performed at every visit. Radiographic changes in graft height were calculated with respect to the implant's known length and the original sinus height. Results : All implants were stable functionally, as well as clinically and radiographically, during the follow-up. Most of the radiographic reduction in the grafted bone height occurred in the first 2 years; reduction after 2 years was slight. Conclusions: The simultaneous placement of non-submerged SLA implants using the BAOSFE procedure is a feasible treatment option for patients with severe atrophic posterior maxillas. However, the grafted bone height is reduced during the healing period, and patients must be selected with care.

• Journal of Plant Biotechnology
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• 제8권1호
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• pp.15-19
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• 2006

An efficient protocol for in vitro multiple shoot bud induction and plant regeneration from mature green cotyledon derived callus tissues of Acacia sinuata has been developed. Callus formation occurs at all the concentrations of thidiazuron (TDZ) in Murashige and Skoog's (MS) medium, but 0.6 ${\mu}M$ proved to be the best with maximum callus formation frequency. Supplementation of TDZ in combination with indole-acetic acid (IAA) in MS media accelerates shoot bud organogenesis in differentiating callus tissues with 60-70% conversion of shoot buds into shoot Most efficient shoot organogenesis was recorded when TDZ induced calli were subcultured at different concentrations of 6-benzyla-denine (BA). Optimum shoot bud induction and plant regeneration from callus was achieved when 0.6 ${\mu}M$ (TDZ) induced calli were subcultured at 3.0 ${\mu}M$ (BA) where $16.6{\pm}0.74$ shoots/unit callus on obtained. Rooting in in vitro differentiated shoots was achieved when transferred to medium containing different concentration of indole-3-butyric acid (IBA) in full & half strength MS medium. The well rooted plantlets were hardened and transferred to net house with 90% survival rate.

• Plant Biotechnology Reports
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• 제3권4호
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• pp.341-345
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• 2009

This study describes culture conditions for a plant regeneration system via a combined pathway of somatic embryogenesis and organogenesis in root explant cultures of the commercial rose cultivar 'Charming'. Root explants formed white calluses at a frequency of 30% after 6 weeks of culture on Schenk and Hildebrandt (SH) medium supplemented with $11mg\;1^{-1}$ 2,4-dichlorophenoxyacetic acid. After 6 weeks of transfer to SH medium without growth regulators, initial white calluses gave rise to globular somatic embryos at a frequency of 2.8%, which were subsequently dedifferentiated to embryonic tissues. Somatic embryos or embryonic tissues initially derived from root explants did not undergo development beyond cotyledonary stage. To produce adventitious shoots, embryonic tissues were sliced and cultured on SH medium with $0.5mg\;1^{-1}$ 6-benzyladenine. After 4 weeks of culture, 28% of embryonic tissue explants formed adventitious shoots. Regenerated shoots were rooted on half strength SH medium with $0.1mg\;1^{-1}$ ${\alpha}-naphthalaneacetic$ acid and subsequently grown to maturity. Root-derived embryonic tissues were proliferated by subculture, while retaining the capacity for shoot production for a few years.

• 한국수산과학회지
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• 제24권5호
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• pp.356-361
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• 1991

This study was conducted to determine the decomposition rate constants of organic matter and to evaluate the process of regeneration of inorganic nutrients in coastal and open seawater. The mixture solution of glucose and glutamic acid, and night soil were used as the test organic matter. Oxygen uptake of test solution was observed every day for 5 days for evaluation of decomposition rate constants, and nutrient contents were analyzed every day for 40 days. The decomposition rate constants have been determined by Thomas slope method and compared with the values of each waters. The values of rate constants for open seawater and coastal water containing the mixture of glucose and glutamic acid were 0.23/day and 0.21/day, and those containing night soil 0.23/day and 0.20/day, respectively. The difference of decomposition rate constants between test materials was not found and the valus for each seawater was equal to each other. The nitrification process took place after 22 days for open seawater when night soil was added to the waters.