Judul: Gene Marker Construction of Plantaricin F Lactobacillus plantarum.
Abstrak: Lactobacillus plantarum merupakan bakteri yang dapat berperan sebagai probiotik. Bakteri ini memiliki plantaricin F yang berguna menghambat pertumbuhan bakteri Gram positif dan negatif. Penelitian ini menggunakan sepuluh isolat L. plantarum (Mar A5, Bst 1, Mar C7, TB(N), Mg Tm 1, Mg PSM B3, TB(S), MKw 9, Bst 5, Mar B4) yang berasal dari buah-buahan tropis (mangga kweni, manggis, markisa, dan terong belanda). Penelitian ini dilakukan untuk konstruksi marka gen pln F dan menganalisis ekspresi relatif gen pln F serta uji aktivitas antibakteri. Pengujian gen pln F menggunakan RT-PCR menghasilkan pita DNA berukuran 70 pb. Hasil pengujian ini selanjutnya dipakai untuk menentukan nilai ekspresi relatif gen pln F menggunakan software CS Analyzer. Nilai ekspresi relatif gen tertinggi didapat dari isolat TB (S) dengan nilai 28.13 Au. Uji aktivitas antibakteri dilakukan untuk melihat hubungan antara gen pln F dengan aktivitas penghambatan isolat terhadap bakteri uji. Uji aktivitas antibakteri dilakukan terhadap lima bakteri antara lain Salmonella typhimurium, Staphylococcus aureus, Escherichia coli, Bacillus cureus, dan Pseudomonas flouresense. Penghambatan tertinggi terhadap S. aureus terdapat pada isolat Mg PSM B3 dengan diameter penghambatan 2.50 cm. Isolat Mar A5 memiliki penghambatan tertinggi terhadap bakteri S. typhimurium, E. coli, dan P. flouresense dengan diameter penghambatan masing-masing 1.33 cm, 1.83 cm, dan 1.16 cm. Isolat Mar B4 dan Bst 5 memiliki penghambatan tertinggi terhadap bakteri B. cureus dengan diameter sekitar 0.50 cm.
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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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