Judul: Kloning Gen Penyandi Sukrosa Sintase Dari Tanaman Sengon (Paraserianthes falcataria)
Abstrak: Salah satu aspek yang dipelajari dan diteliti untuk meningkatkan kualitas kayu sengon (Paraserianthes falcataria) adalah peningkatan deposisi selulosa. Sukrosa sintase merupakan salah satu enzim kunci yang berperan dalam biosintesis selulosa. Sukrosa sintase mengkatalisis reaksi konversi sukrosa + UDP UDP-glukosa + fruktosa. Enzim ini terlibat dalam biosintesis selulosa dengan cara menghubungkan UDP-Glukosa ke mesin sintesis selulosa (selulosa sintase). Penelitian yang terkait dengan gen penyandi sukrosa sintase yang terlibat pada biosntesis selulosa pada sengon masih terbatas. Tujuan dari penelitian ini adalah untuk mengisolasi dan mengkloning gen penyandi sukrosa sintase yang bersumber dari sengon dengan teknik RT-PCR (sintesis cDNA) menggunakan primer yang spesifik. Kandidat gen yang berhasil diisolasi ditransformasikan ke bakteri Escherichia coli menggunakan vektor plasmid pGemT-Easy. Dari hasil sekuensing fragmen cDNA sukrosa sintase diperoleh 341 pb nukleotida yang menyandi 112 asam amino. Studi homologi yang dilakukan pada sekuens basa nukleotida dan protein penyandi sukrosa sintase sengon terhadap basa nukleotida dan protein penyandi sukrosa sintase dari tanaman lain menunjukkan bahwa sekuens gen penyandi sukrosa sintase pada sengon memiliki kesamaan dengan Glycine max, Citrus unshiu, Vigna radiata dan Arabidopsis thaliana dengan tingkat kesamaan masing-masing 79%, 78%, 75% dan 73%.
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Judul: Cloning Method of Pest Resistance Gene from Sengon (Paraserianthes falcataria).
Abstrak: Sengon is one of fast growing trees species, which is widely cultivated in plantations forest in Indonesia due to its multipurpose nature, and easy to grow. The plantation, however, faces serious problem of stem borer (Xystrocera festiva) attack, which was reported could destroyed sengon plantation. Meanwhile, several studies have reported the role of trypsin inhibitors (TI) and alpha-amylase inhibitor (AAI) in resistance in trees to insects. This research aimed at cloning a possible pest resistance gene from sengon. Sengon genomic DNA was isolated using CTAB buffer combined with binding columnn of GenElute plant Genomic DNA Miniprep Kit. Designed primer pairs did not generate amplicon. PCR products were obtained from published degenerate primers as two amplicons, with predicted size of 350 bp and 550 bp for AAI gene, and 600 bp and 800 bp for TI gene. Cloning with pGEM-T Easy vector resulted in several white colonies. Sequencing from selective colonies with long and short amplicon of AAI and TI sequences with 693 nucleotide, 278 nucleotide and 832 nucleotide, 278 nucleotide, respectively. BLASTN and BLASTX the sequences did not confirm that the inserts were AAI and TI genes. Further research is still needed to identify pest resistance gene in sengon tree.
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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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