• Plant Biotechnology Reports
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• 제2권3호
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• pp.179-189
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• 2008

We established an efficient plant regeneration system for Catharanthus roseus L. (G.) Don through somatic embryogenesis. Embryogenic callus was induced from hypocotyl of seed germinated in vitro. Somatic embryogenesis in Catharanthus has been categorized into three distinct stages: (1) initiation and proliferation of embryo; (2) maturation, and; (3) germination or plantlet conversion. Beside plant growth regulators, various stages of embryogenesis were screened for their response to a wide variety of factors (pH, gelrite, light, sugar alcohols, polyethyleneglycol and amino acids), which affect embryogenesis. All of the tested factors had a small to marked influence on embryogeny and eventual conversion to plantlets. The plantlets were acclimatized successfully in a greenhouse. To our knowledge, this is the first report describing a detailed study of various cultural factors which regulate embryogenesis in C. roseus. The results discussed in this paper may be used in mass propagation to produce medicinal raw material, and the embryo precursor cells could be used in genetic modification programmes that aim to improve the alkaloid yield as well.

• Journal of Plant Biotechnology
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• 제30권2호
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• pp.167-172
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• 2003

Immature zygotic embryos of Eleutherococcus senticosus seeds matured rapidly within one month when the seeds comprising zygotic embryos were pieced to small size and cultured on 1/2 MS medium. Frequency of somatic embryos formation was declined rapidly when the zygotic embryos germinated and grew to plantlets. Embryogenic cells were induced by consecutive subculture of somatic embryos on MS medium with 1.0mg/L2,4-D. After heart-shaped somatic embryos were induced by suspension culture, these embryos were plated onto petri dish to support maturation of embryos. Germination of embryos occurred on medium with 5mg/L GA$_3$and transferred to culture bowl to stimulate the further growth. Frequency of soil survival of plantlets was influenced by soil mixture (perlite and peatmoss). The suitable combination of perlite and peatmoss was 1:5, and the soil survival rate was 78% after 4 months. The soil transferred plantlets were over-wintered in field condition after defoliation. New year sprouting of plants was achieved successfully and they grew to adult plants. These results indicate that the systematic procecure of plant production in E. senticosus for micro propagation.

• Journal of Plant Biotechnology
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• 제4권2호
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• pp.71-76
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• 2002

In order to achieve repetitive somatic embryogenesis in cacao (Theobroma cacao L.), callus derived from floral tissues were continuously cultured in a medium containing 2,4-D. In 5% of the explants, repetitive somatic embryogenesis was observed after 8 weeks and maintained in a globular stage for several weeks. This is the first report showing repetitive somatic embryogenesis in cacao. The calli were bombarded with a plasmid containing $\beta$-glucuronidase (gus) as reporter gene. Two week old calli showed the high average number of cells expressing the us gene. The effect of osmotic agents (mannitol, sorbitol and sucrose) on gene expression was evaluated. Pre-treatment during 16 h with 0.25 M mannitol revealed an improvement in gene expression. The potential utilization of the repetitive embryogenesis, combined with osmotic treatment, is discussed as an alternative to achieve stable transgenic cacao plants.

• 한국약용작물학회지
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• 제12권6호
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• pp.494-499
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• 2004

체세포배발생을 이용한 가시오갈피 대량증식체계 확립을 위하여 저온처리에 의한 체세포배의 장기저장 실험을 수행하였다. 현탁배양 체세포배의 $4^{\circ}C$에서의 저온저장에는 구형배 이전의 조기단계의 체세포배가 적합하였고 $2\;g/{\ell}$ 이하의 낮은 접종밀도에서는 36개월 이상 저장이 가능하였다. 장기간 저온 저장한 체세포배는 상온에 옮긴 후 2,4-D를 첨가한 배지에서만 성장을 회복하여 배발생캘러스를 형성하였으며 배발생캘러스의 증식속도는 배양온도를 $32^{\circ}C$로 높였을 때에 가장 효율적이였다.

• Journal of Plant Biotechnology
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• 제32권2호
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• pp.135-138
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• 2005

더덕 자엽절편을 1 mg/L 2,4-D가 첨가된 MS기본배지에 배양하여 배발생캘러스를 얻었고, 호르몬이 첨가되지 않은 MS액체배지에서 구형기의 체세포배를 얻었다. 구형기에서 초기 심장형기로 발달할 때 자엽의 시원세포는 전형성층조직으로부터 분화되기 시작 하였으며, 하배축에서 관찰되는 원통형 전형성층대는 2개의 자엽을 형성할 경우 2개의 전형성층대가, 3개의 자엽은 3개의 전형성층대가, 4개의 자엽은 4개의 전형층대가 각각 독립적으로 분화되어 자엽절과 자엽부위까지 연결되어 있었다. 만약 구형기 체세포배에서 자엽시원세포가 원통형으로 분화될 경우 합생자엽을 갖는 체세포배가 형성되었다.

• 한국산림과학회지
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• 제85권4호
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• pp.667-679
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• 1996

최근에 임목의 영양번식체계나 우량묘목을 양성하기 위하여 임목의 체세포배를 이용해서 "인공종자" 형태로 보관하거나 연속배양기를 사용하여 계속적으로 체세포배를 생산하는 방법은 매우 중요한 기법에 속한다. 이러한 체세포 배양기법은 임목의 생물공학 뿐만아니라 체세포배 발생학, 세포 및 분자생물학 연구에 있어서 중요한 역할을 한다. 현재 침엽수 체세포 배양에 대한 복잡한 기작이 많이 밝혀지고 있으나 이러한 기초적 지식이 현실적으로 잘 응용되지 못하는 점이 임목생물공학의 발전을 저해하는 요소로 지적되고 있다. 본 총설에서는 이러한 기초적 지식을 침엽수 체세포배 배양의 응용적 연구에 이용하는데 초점을 맞추었다.

• 한국동물생명공학회지
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• 제35권3호
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• pp.215-222
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• 2020

Mesenchymal stem cells (MSCs) have been widely used as donor cells for somatic cell nuclear transfer (SCNT) to increase the efficiency of embryo cloning. Since replicative senescence reduces the efficiency of embryo cloning in MSCs during in vitro expansion, transfection of telomerase reverse transcriptase (TERT) into MSCs has been used to suppress the replicative senescence. Here, TERT-transfected MSCs in comparison with early passage MSCs (eMSCs) and sham-transfected MSCs (sMSCs) were used to evaluate the effects of embryo cloning with SCNT in a porcine model. Cloned embryos from tMSC, eMSC, and sMSC groups were indistinguishable in their fusion rate, cleavage rate, total cell number, and gene expression levels of OCT4, SOX2 and NANOG during the blastocyst stage. The blastocyst formation rates of tMSC and sMSC groups were comparable but significantly lower than that of the eMSC group (p < 0.05). In contrast, tMSC and eMSC groups demonstrated significantly reduced apoptotic incidence (p < 0.05), and decreased BAX but increased BCL2 expression in the blastocyst stage compared to the sMSC group (p < 0.05). Therefore, MSCs transfected with telomerase reverse transcriptase do not affect the overall development of the cloned embryos in porcine SCNT, but enables to maintain embryo quality, similar to apoptotic events in SCNT embryos typically achieved by an early passage MSC. This finding offers a bioengineering strategy in improving the porcine cloned embryo quality.

• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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• pp.189-192
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• 2001

This study was initiated in an effort to determine the normal mean and variations of the somatic cell count (SCC) in milk of buffaloes as influenced by the milking time, stage of lactation, parity and season. The buffaloes were hand milked at 13 and 11 h. interval during evening and morning respectively. On the day of milk sampling the udders were tested for mastitis by California Mastitis Test (CMT). Only those buffaloes, which were found negative in the CMT, were included in the sampling plan. The mean values for morning and evening were 1.09 (range 0.39-1.76) and $0.97(range\;0.57-2.46){\times}10^5cells/ml$, respectively which did not differ significantly. When data of the morning and evening values was compared on the basis of total cell secretion in milk, even then there was no statistical difference between the morning and the evening values, thereby suggesting that no diurnal variation existed in SCC of milk. Paritywise differences were not significant between the 1st to 5th lactation and above. Similarly stage of lactation effect, when tested at 30 day intervals, did not differ significantly. Significant (p<0.05) correlation coefficients (r) between SCC and milk yield during different stages of lactation and parity suggested that SCC per ml of milk was higher during the later stages of lactation. SCC was higher in primiparous than in multiparous buffaloes. On an average the SCC recorded was $1.0{\times}10^5cells/ml$ of milk irrespective of time of milking, parity and stages of lactation. The SCC was low during cold and hot-dry season but were high during the hot-humid season (p<0.05), the respective values being 0.76, 1.08 and $1.35{\times}10^5cells/ml$. These values were lower than the SCC already reported in cows suggesting less stressful condition of the udder of buffaloes in this study.

• 한국수정란이식학회지
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• 제15권1호
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• pp.23-31
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• 2000

This study was conducted to investigate the effects of quiescent treatment of donor cells and activation treatment time of recipient cytoplasm on nuclear remodeling and in vitro development of somatic cell-cloned bovine embryos. Serum starved, confluent and nonquiescent cycling adult skin cells were teansferred into enucleated oocytes. Nuclear transfer oocytes were activated at 30 min, 1 and 2 hrs after electrofusion. Some nuclear transfer embryos(23% to 35%) extruded a polar body, which was not affected by quiescent treatment of donor cells and activiation time of recipient cytoplasm. About 68% of nuclear transfer embryos fused with a serum starved cells has a chromatin clump, but which was not different from embryos fused with confluent(51%) and nonquiescent(47%) cells. The proportion of embryos with a single chromatin clump was sightly increased when nuclear transfer embryos were activated within 30 min after fusion(69%) compared to those were activated at 1 and 2 hrs after fusion, but there was not significantly different. Development rates to the blastocyst stage were 8.6% and 15.9% when serum starved and confluent cells were transferred, which were higher than that of control group. Developmental rate to the blastocyst stage was higher in embryos were activated within 30 min after fusion (17.3%) compared to those of embryos were activated at 1 and 2 hrs after fusion (P<0.05). From the present result, it is suggested that quiescent treatment of donor cells and activation time of recipient cytoplasm can affect the in vitro development. Quiescent plasm activation within 30 min after fusion could increase the number of embryos with a normal chromation structure, which results in increased in vitro development.

• BMB Reports
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• 제54권10호
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• pp.505-515
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• 2021

Human pluripotent stem cells (hPSCs) include human embryonic stem cells (hESCs) derived from blastocysts and human induced pluripotent stem cells (hiPSCs) generated from somatic cell reprogramming. Due to their self-renewal ability and pluripotent differentiation potential, hPSCs serve as an excellent experimental platform for human development, disease modeling, drug screening, and cell therapy. Traditionally, hPSCs were considered to form a homogenous population. However, recent advances in single cell technologies revealed a high degree of variability between individual cells within a hPSC population. Different types of heterogeneity can arise by genetic and epigenetic abnormalities associated with long-term in vitro culture and somatic cell reprogramming. These variations initially appear in a rare population of cells. However, some cancer-related variations can confer growth advantages to the affected cells and alter cellular phenotypes, which raises significant concerns in hPSC applications. In contrast, other types of heterogeneity are related to intrinsic features of hPSCs such as asynchronous cell cycle and spatial asymmetry in cell adhesion. A growing body of evidence suggests that hPSCs exploit the intrinsic heterogeneity to produce multiple lineages during differentiation. This idea offers a new concept of pluripotency with single cell heterogeneity as an integral element. Collectively, single cell heterogeneity is Janus-faced in hPSC function and application. Harmful heterogeneity has to be minimized by improving culture conditions and screening methods. However, other heterogeneity that is integral for pluripotency can be utilized to control hPSC proliferation and differentiation.