Judul: Isolasi dan Karakterisasi Gen Plantaricin EF dan JK dari Lactobacillus plantarum S34
Abstrak: Lactobacillus plantarum S34 menghasilkan bakteri osinse lama proses fermentasi asam laktat berlangsung. Bakteriosin yang dihasilkan oleh L.plantarum disebut plantaricin. Plantaricin disandikan oleh gen penyandinya masing-masing, seperti plantaricin EF disandikan oleh gen plantaricin EF danplantaricin JK disandikan oleh gen plantaricin JK. Tujuan penelitian ini adalah melakukan isolasi dan karakterisasi gen plantaricin EF dan JK dariL. plantarumS34. Gen plantaricin EF dan JK diamplifikasi dari DNA genomL. plantarum S34 dengan primer spesifik menggunakan Teknik Polymerase Chain Reaction (PCR). Hasil analisis menggunakan BLAST menunjukkan gen plantaricinEF dan JK hasil isolasidariL. plantarum S34 masing-masing tersusun atas 285 bpdan 267 bpnukleotida. Produk PCR diurutkan untuk mengetahui urutan basanu kleotida gen plantaricin EF dan JK. Hasil analisis urutan nukleotida menunjukkan gen plantaricin EF dan JK memiliki Ribosome Binding Site (RBS), start codon, danstop codon (TAG pada gen plantaricin EF dan TAA pada gen plantaricin JK). Hasil analisis urutan nukleotida juga menunjukkan plantaricin yang disandikan oleh gen plantaricin EF dan JK secara berturut-turut tersusun atas 52 dan 56 asam amino, serta memiliki motif GG (double glycine) padaleader peptide (padaplantaricin EF terjadi mutase pada salah satu penyusun motif GG menjadi serin) dan motif Gxxx G pada mature peptide seperti halnya plantaricin lain yang termasuk kedalam bakteri osin kelas IIb. Jumlah motif GxxxG yang dimiliki oleh plantaricin EF sebanyak satu motif, yaitu GFIHG sedangkan jumlah motif GxxxG yang dimiliki oleh plantaricin JK sebanyak dua motif, yaitu GYAIG dan GYAFG.
Keyword: bacteriocin, lactic acid fermentation process, BLAST analysis, the genomic DNA

Judul: Konstruksi Gen Penyandi Plantaricin S dari Lactobacillus plantarum S34
Abstrak: Bacteriocins are antibacterial peptides that commonly used as food biopreservative. Bacteriocins were produced by both either Gram positive or Gram negative bacteria, one of them is Lactobacillus plantarum S34 isolated from beef bekasam. L. plantarum S34 produced bacteriocins called plantaricin. PlnS gene is gene that encoding plantaricin. The study purposed is to isolate plnS gene from L. plantarum S34. The plnS gene amplified by PCR (Polymerase Chain Reaction) technique, and then cloned into cloning vector pGEM-T Easy and transformed into E. coli DH5α. Transformation gene using heat shock method. Selection of transformants using the blue and white colonies. Gene amplification produces plnS gene amplicon size about ±500 bp. PlnS gene ligation with pGEM-T Easy (3015 bp) vector generating plasmid size about ±3500 bp. The confirmation of white colonies from blue-white screening was carried out with PCR colony, generated amplicons size was about ±500 bp. Recombinant plasmid in colony 2 was confirmed by restricition analysis using SalI and NcoI. The result showed that the gene insert had expected size ±500 bp.
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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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