Judul: Deteksi Geminivirus yang menginfeksi tanaman terung (Solanum melongena L.) dengan teknik Polymerase Chain Reaction.
Abstrak: Diseases caused by whitefly-transmitted Geminiviruses (WTGs) have become serious constraints for crops throughout the world, including Indonesia. WTGs has been reported to cause significant yield loss especially in chili pepper and tomato in Java. This research aims to detect and identify Geminivirus infecting eggplant using polymerase chain reaction (PCR) and nucleotide sequencing. The methods involved DNA extraction using CTAB, DNA amplification and nucleotide sequence analysis by Bioedit V 7.0.5 and ClustalW. Three pair of universal primers, i.e. pAL1v1978/pAR1c715, SPG1/SPG2, pAV494/pAC1048, was used for DNA amplification. Infection of Geminivirus was evidenced from leaves collected from West Java (Bandung) and Central Java (Pati, Rembang, Bantul). Universal primer SPG1/SPG2 was able to amplify DNA fragments of ≈912 bp from all leaf samples. Nucleotide analyses showed that Geminivirus infecting eggplant from West Java and Central Java has a close relationship (98.8%) with Tomato yellow leaf curl Kanchanaburi virus (TYLCVKaV) from Thailand.
Keyword: universal primers., sequence analysis, DNA amplification

Judul: Identifikasi Spesies Begomovirus Penyebab Penyakit Daun Kuning pada Tanaman Mentimun melalui Analisis Sekuen Nukleotida
Abstrak: Yellow vein mosaic disease on Cucurbitaceae is known to be associated with infection of Tomato leaf curl NewDelhi virus (ToLCNDV) or Squash leaf curl China virus (SLCCNV). Last year, a yellowing disease with typical vein banding without any leaf malformation on cucumber (Cucumis sativus) in Bali was found to be induced by SLCCNV. This year, cucumber cultivation in West Java was affected by severe incidence of a disease resemble with that occurred in Bali. This research aimed to elucidate if the disease on cucumber plants emerged in West Java is also caused by SLCCNV. Total nucleic acid extractions of cucumber leaves collected from three villages in Bogor (Cikarawang, Petir, and Sindangbarang) were made separately and used for PCR amplifications using a pair of primers (SPG1: 5'-CCCCKGTGCGWRAATCCAT-3' and SPG2: 5'- ATCCVAAYWTYCAGGGAGCTAA-3') designed to match the sequences of the DNA-A of Begomovirus. PCR from all three samples yielded amplified DNA fragments of the expected sizes of 912 bp, indicated the association of the virus with the disease. The DNA sequence of the PCR products shared more than 95% sequence identity with ToLCNDV isolates available in the GenBank and clustered with them in the phylogenetic analysis. This finding confirmed that SLCCNV was not spread yet (from Bali) to West Java
Keyword: Polimerase chain reaction, Tomato leaf curl NewDelhi virus, yellowing disease

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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