Judul: Transformasi Genetik Tembakau dengan Gen BtCspB Penyandi Cold Shock Protein Melalui Perantara Agrobacterium tumefaciens
Abstrak: Cold shock protein (Csp) is essential for organisms to survive in the abiotic stress condition. It protects RNA from misfolding caused by various abiotic stresses. BtCsp gene had been isolated from Bacillus thuringiensis, fused to promoter of ubiquitin in the T-DNA of pCambia 1300int, and introduced into Agrobacterium tumefaciens LBA4404. We suppose that plant overexpressing this gene would be tolerant to abiotic stress including cold heat and drought stress. This research had an objective to transform genetically Nicotiana tabacum cv Samsun by BtCsp gene under the control of pUbiquitin promoter and NosT terminator mediated by A. tumefaciens. Leaf disks were inoculated by the method of co-cultivation with A. tumefaciens LBA4404 harboring pCambia1300int-BtCspB. We compared the effect of shoaking time between 20 and 30 minutes on the transformation efficiency. The transformation calli were selected on the medium containing 20 mg/l and 50 mg/l hygromcin and regenerated on MS medium containing 1 mg/l BAP and 0,1 mg/L IAA. Based on resistant calli to 50 mg/l hygromicin, the efficiency of transformation between 20 and 30 minutes was selatively equal i.e 65% and 57.5% respectively. PCR analaysis showed that BtCspB gene under the control of Ubquitin promoter is integrated into N. tabacum genome of To generation. Genetic analysis showed that hpt gene was inherited to the progeny T1 generation following Mendalian law. Based on chi-square analysis, the ratio of resistant and sensitive plant To hygromycin in T1 generation was 3:1, indicating that only one copy of hpt gene was integrated into the genome of transgenic plant in To generation.
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Judul: Teknik Transformasi Genetik beberapa Tanaman Menggunakan Agrobacterium tumefaciens
Abstrak: Transformasi genetik adalah proses introduksi gen dari satu organisme ke organisme lain yang memungkinkan untuk memunculkan sifat harapan tanpa mengubah sifat lain. Penggunaan Agrobacterium tumefaciens sebagai vektor transformasi memiliki keunggulan karena tidak membutuhkan peralatan khusus serta efisiensi transformasi dan salinan tunggal dari gen yang ditransformasi relatif tinggi. Penelitian ini merupakan penelitian transformasi komparatif pada beberapa tanaman yang memiliki karakter berbeda, yaitu manggis sebagai tanaman apomiksis, tembakau sebagai tanaman model, anggrek sebagai perwakilan dari kelas monokotil, dan kopi sebagai perwakilan dari kelas dikotil. Transformasi dilakukan dengan metode yang sama dan dilanjutkan dengan regenerasi pada media seleksi yang mengandung antibiotik. Konfirmasi sisipan gen hasil transformasi dilakukan dengan teknik Polimerase Chain Reaction (PCR). Hasil konfirmasi dari sampel tanaman yang mampu tumbuh pada media seleksi menunjukkan hanya tembakau yang positif tersisipi oleh gen yang ditransfomasi. Hal ini menunjukkan bahwa tanaman hasil transformasi yang mampu hidup di media seleksi belum merupakan jaminan tersisip oleh gen yang diintroduksi sebelum dilakukan pengujian molekuler. Beberapa optimasi dalam sterilisasi, teknik infeksi, peningkatan jumlah eksplan yang ditransformasi dan jumlah sampel yang diuji perlu dilakukan untuk peningkatan efisiensi transformasi.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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