작약(Paeonia lactiflora Pall.) 동아의 경정배양을 통한 기내증식

정재동,한증술,지선옥 한국식물생명공학회 1995 식물생명공학회지 Vol.22 No.2

작약동아의 정아 및 액아의 기내배양에 의한 유묘의 증식에 필요한 배양조건을 구명코자 실험한 결과는 다음과 같다. 정아배양의 경우, 생장조절재의 조성에 무관하게 두지방종에서 100% 신초가 신장하였으나 생장은 의성지방종 은 NAA 0.1 mg/L 단용배지, 영천지방종은 NAA 0.01 mg/L 단용배지에서 가장 양호하였다. 액아배양의 경우, NAA 0.01 mg/L와 zeatin 5.0 mg/L 혼용배지에서 의성지방종은 100%, 영천지방종은 50%의 가장 높은 신초신장율을 보였고 신초의 생장도 양호한 경향이었다. 정아 및 액아배양으로부터 유도된 신초는 vermiculite를 지지물로 한 NAA 0.1 mg/L 첨가배지에서 30.0%의 발근율을 보였으나 뿌리의 생장은 양호하였다. The experiment was conducted to identify the optimal in vitro propagation condition for P. lactiflora Pall. Through apical shoot tip and axillary shoot tip culture of winter bud. When apical shoot tip and axillary shoot tips excised from winter bud were cultured on MS medium supplemented with various concentrations of plant growth regulators, all the apical shoot tips elongated regardless of the composition of the medium but axillary shoot tips responded differently. Shoot of 'Uisong' local cultivate was well elongated in the medium containing 0.01mg/L NAA. Frequency of shoot formation and subsequent shoot growth in axillary shoot tip culture were promoted in the medium containing 0.01 mg/L NAA and 5.0mg/L zeatin. 30% of the elongated shoots were vigorously rooted on the medium containing 0.1mg/L NAA with vermiculite as a support medium.

Petunia hybrida와 Nicotiana sanderae의 원형질체융합에 의한 잠정적 체세포잡종 식물체 생산

정재동,노영희,최수옥,지선옥 한국식물생명공학회 1995 식물생명공학회지 Vol.22 No.2

Petunia hybrida와 Nicotiana sanderae의 원형질체를 융합하여 체세포잡종식물을 얻고자 융합산물의 배양에 의해 얻은 개체들에 대해 유전분석을 하였다. 재분화 개체중 융합된 것으로 인정되는 개체의 peroxidase pattern은 두 모본의 band를 모두 가진 개체(A-D patterns)에서 나타난 band중 p. hybrida에서 나타난 band 이외에 최상부에 1개의 band가 추가되었는데 이는 융합을 판별할 수 이는 중요한 marker 로서 가능성이 있으며, aspartate aminotransferase isoenzyme pattern은 두 모본의 양상이 모두 나타나거나 N. sanderae의 상부 band가 소실된 개체도 있었다. 염색체 검경에서 P.hybrida는 2n=14, M sanderae는 2n=18개로 나타났으며, 동위효소검정에서 체세포 잡종일 것으로 추정되는 개체들은 2n=32-36으로 나타났다. 표현형 관찰에서 체세포잡종으로 인정되는 개체의 형태적 특징은 두 모본의 중간형태를 나타내었다. The experiment were carried out to obtain a somatic hybrid through protoplast fusion between P.hybrid and N. sanderae. The isoenzyme pattern he chromosome number and the phonotype were observed for genetic study on the regenerants obtained from the fusion product cultures. Putative somatic hybrids possessed all the bands that appeared in both mother plane. A specific band was found on the top of the banding pattern which was assumed to be a marker band of somatic hybrid between two genera. Aspartate amninotransferase isoenzyme bands which were found in both mother plane were also revealed in the putative somatic hybrids or deleted in the upper part of H. sanderae band pattern. The chromosome number of P.hybrida was 2n=14, while N, sanderae was 2n=18,but the number of the putative somatic hybrids ranged from n=32 to 36. The phonotype of putative somatic hybrids was intermediate of the mother plants.

형질전환 상추에서 배추 Glutathione Reductase 유전자의 발현

정재동,김창길,조진기 한국식물생명공학회 1998 식물생명공학회지 Vol.25 No.4

상추의 자엽 조직을 GR 유전자가 도입된 A. tumefaciens LBA 4404와 2일간 공동배양후, carbenicillin 500mg/L, kanamycin 50mg/L NAA 0.1mg/L와 2iP 1.0 mg/L가 함유된 MS 재분화배지에 옳겨 약 4주후에 kanamycin 저항성 개체를 얻었다. 형질전환된 것으로 추정되는 식물체는 kanamycin 100mg/L가 함유된 MS선발배지에서 생존하였다. PCR 분석결과, GR 유전자가 형질전환체의 게놈상에 삽입되어 있음을 확인하였다. 형질전환체의 Southern blot 분석을 통하여 ECL-labelling된 GR 유전자와 동일한 것으로 판단되는 약 1.8 kb 위치에서 밴드를 확인할 수 있었다. RT-PCR 분석으로 GR 유전자가 전사됨을 확인할 수 있었다. 개화후 이들 개체의 종자를 받아 NPTII 유전자의 발현여부를 조사한 결과 R$_1$ 세대에서도 NPTII 유전자가 발현됨을 확인하였다. Cotyledon explants of lettuce were cocultured with Agrobacterium tumefaciens LBA4404::pBKS-GR1 harboring glutathione reductase(GR) gene in MS medium supplemented with 0.1 mg/L NAA and 1.0 mg/L 2ip for 48 hr. These explants were transferred to MS medium supplemented with 0.1 mg/L NAA and 1.0 mg/L 2ip, 50 mg/L kanamycin, and 500 mg/L carbenicillin. After 4 weeks of subculture, kanamycin-resistant shoots were obtained on selection medium. Leaves of putative transformants survived on selection medium containing 100 mg/L kanamycin. Incoporation of the GR gene into lettuce was confirmed by PCR analysis of genomic DNA. Southern blot analysis showed that ECL-labeled GR gene was hybridized to the expected amplified genomic DNA fragment of about 1.8 kb from transgenic lettuce. The presence of mRNA in transgenic lettuce was confirmed by RT-PCR with total RNA of transgenic lettuce. In progeny test of transformants, R$_1$ seeds were resistant to kanamycin (200mg/L) on MS medium.

Petunia hybrida 세포내로의 rolC 유전자의 도입

정재동,김경민,남윤연,김창길,정원일 한국식물생명공학회 1999 식물생명공학회지 Vol.26 No.1

쌍떡잎식물체 형질전환에 널리 쓰이는 Agrobacterium의 binary vector를 이용하여 왜화성을 나타내는 pGA643-rolC gene을 엽절편 transformation방법으로 petunia에 도입하였다. Petunia hybrida의 재분화에 있어 엽조직으로부터 식물체 재분화에 미치는 생장조절물질의 효과는 0.1mg/L NAA와 1.0mg/L BA의 조합에서 높았고 재분화된 식물체도 양호하였다. 식물체 형질전환 선발배지에 에틸렌 억제제인 AgNO$_3$와 KMnO$_4$의 첨가시 형질전환체 재분화율이 높게 나타났으며, AgNO$_3$에 비해 KMnO$_4$처리구에서 보다 많은 식물체 재분화율을 나타내었으나 AgNO$_3$와 KMnO$_4$의 고농도 첨가시 다소의 유리화 현상이 발생하였으므로 3mg/L KMnO$_4$ 첨가가 식물체 재분화에 적합한 것으로 생각된다. 항생제 200mg/L kanamycin, 500mg/L carbenicylin 과 1.0 mg/L BA, 0.1mg/L NAA가 첨가된 형질전환 선발배지에서 엽절편으로 부터 형질전환 된 것으로 추정되는 식물체들을 일차 선발하였고 기외로 이식한 후 genomic DNA를 분리하여 Southern blot analysis법으로 분석한 결과 외래 유전자가 식물체의 genomic DNA내로 삽입된 것을 확인할 수 있었다. These experiments were attempted to introduce rolC gene in the Petunia hybrida cv. Titan white by Agrobacterium mediated. The maximum frequency of shoot regeneration was obtained by 60% on MS medium containing 1.0 mg/L BA, 0.1 mg/L NAA, 200 mg/L kanamycin, 500 mg/L carbenicillin, 30 g/L sucrose, and 8 g/L agar. Kanamycin-resistant calli were selected from petunia leaf discs by cocultivation with Agrobacterium suspension cultures on MS medium. The addition of AgNO$_3$ and KMnO$_4$ in the medium increased the shoot regeneration by 31.3% from leaf disc as compared with non-treated leaf disc. Among clones exhibiting kanamycin resistance, only 3 clones were confirmed by southern hybridization analysis.

혼합물의 응고문제에 대한 확장된 해석해

정재동,유호선,이준식,Jeong, Jae-Dong,Yu, Ho-Seon,Lee, Jun-Sik 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.2

This paper deals with an extended analytical solution for the mixture solidification problem, in which temperature is inherently coupled with the solute transport due to the presence of volume contraction induced flow. A new exact solution to the energy equation accounting for the convection effect in the melt is successfully derived, which allows the present analysis to cover a high initial superheating. Difference in properties between the solid and liquid phases is rigorously incorporated into the model equations in the solid fraction weighted form. Taking advantage of linearized correction factors, a systematic and easy-to-implement algorithm for determining the solidus and liquidus positions is introduced, which proves not only to converge stably but also to be very efficient. For a specific case, the present results show excellent agreements with the existing solution. The effect of convection in the melt becomes appreciable with increasing the initial superheating. It is revealed that variable properties in the mushy region significantly affect the solidification behaviors. The present study is also capable of resolving the interaction between microsegregation and macrosegregation.

수평동심환상공간내 자연대류의 다중해에 관한 수치적 연구

정재동,김찬중,이준식,유호선,Jeong, Jae-Dong,Kim, Chan-Jung,Lee, Jun-Sik,Yu, Ho-Seon 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.2

Steady-state two-dimensional natural convective heat transfer in horizontal cylindrical annuli was studied by solving the governing equations based on the primitive variables. Emphasis was put on the occurrence of the multiple solutions at a given set of parameter values, and on the determination of the bifurcation points at which those multiple solutions begin to branch out. The multicellular flow pattern from the results of melting process in an isothermally heated horizontal cylinder for high Rayleigh numbers, was used as initial guesses for the field variables. This was succeeded in new bifurcation point to tetracellular solutions for an identical set of parameter variables of previous works. The close examination of flow pattern transition around bifurcation point was also conducted. It was found that the mechanisms of flow transition are different depending on the critical Rayleigh number of bifurcation point.

열농도대류를 고려한 연속주조공정의 수치해석

정재동,유호선,이준식,Jeong, Jae-Dong,Yu, Ho-Seon,Lee, Jun-Sik 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.3

Continuous casting process is numerically analyzed using the continuum model in a non-orthogonal coordinate system. Flow damping in the mush is modeled by combining the viscosity dependence on liquid fraction in dilute mush and the permeability dependence on liquid fraction in concentrated mush. The effect of turbulence is indirectly considered by effective diffusivity determined elsewhere by experiment. The main objective is to investigate the effects of casting parameters such as casting speed and tundish superheat on the distribution of surface temperature, shell thickness, metallurgical length and centerline segregation. Some of the computed results are compared with available experiments, and reasonable agreements are obtained.

역확산을 고려한 이원합금의 비평형 수지상응고 해석

정재동,유호선,이준식,Jeong, Jae-Dong,Yu, Ho-Seon,Lee, Jun-Sik 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.10

Micro-Macro approach is conducted for the mixture solidification to handle the closely linked phenomena of microscopic solute redistribution and macroscopic solidification behavior. For this purpose, present work combines the efficiency of mixture theory for macro part and the capability of microscopic analysis of two-phase model for micro part. The micro part of present study is verified by comparison with experiment of Al-4.9 mass% Cu alloy. The effect of back diffusion on the macroscopic variables such as temperature and liquid concentration, is appreciable. The effect, however, is considerable on the mixture concentration and eutectic fraction which are indices of macro and micro segregation, respectively. According to the diffusion time, the behavior near the cooling wall where relatively rapid solidification permits short solutal diffusion time, approaches Scheil equation limit and inner part approaches lever rule limit.

체적수축유동이 있는 일차원 다원합금 응고에 대한 확장된 해석해

정재동,유호선,최만수,이준식,Chung, Jae-Dong,Yoo, Ho-Seon,Choi, Man-Soo,Lee, Joon-Sik 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.3

This paper deals with a generalized similarity solution for the one-dimensional solidification of ternary or higher-order multicomponent alloys. The present approach not only retains the existing features of binary systems such as temperature- solute coupling, shrinkage-induced flow, solid-liquid property differences, and finite back diffusion, but also is capable of handling a multicomponent alloy without restrictions on the partition coefficient and microsegregation parameter. For an alloy of N-solute species, governing equations in the mushy region reduce to (N+2) nonlinear ordinary differential equations via similarity transformation, which are to be solved along with the closed-form solutions for the solid and liquid regions. A linearized correction scheme adopted in the solution procedure facilitates to determine the solidus and liquidus positions stably. The result for a sample ternary alloy agrees excellently with the numerical prediction as well as the reported similarity solution. Additional calculations are also presented to show the utility of this study. Finally, it is concluded that the present analysis includes the previous analytical approaches as subsets.

연속체모델에 의한 수치해석결과에 대한 재평가

정재동,유호선,노승탁,이준식,Jeong, Jae-Dong,Yu, Ho-Seon,No, Seung-Tak,Lee, Jun-Sik 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.12

In recent years there has been increased interest in the continuum model associated with the solidification of binary mixtures. A review of the literature, however, shows that the model verification was not sufficient or only qualitative. Present work is conducted for the reassessment of continuum model on the solidification problems of binary mixtures widely used for model validation. In spite of using the same continuum model, the results do not agree well with those of Incropera and co-workers which are benchmark problems typically used for validation of binary mixture solidification. Inferring from the agreement of present results with the analytic, experimental and other model's numerical results, this discrepancy seems to be caused by numerical errors in applying continuum model developed by Incropera and co-workers, not by the model itself. Careful examination should be preceded before selecting validation problems.