Judul: Deteksi Pepper vein yellow virus (PeVYV) Penyebab Penyakit Daun Merah pada Tanaman Wortel di Jawa Barat
Abstrak: Red leaf disease (RLD) is a new reported virus disease on carrot in Indonesia. The disease was characterized by reddening of leaves without any retardation of plant development. The disease was resemble to „carrot motley dwarf (CMD)‟ reported worldwide. Although the symptom likely to be similar, these two diseases were caused by two different viruses. CMD was caused by infection of Carrot red leaf virus (Polerovirus). Whereas, RLD was induced by other Polerovirus, Pepper vein yellow virus (PeVYV). PeVYV has a narrow host range, limited on chili pepper. A report that PeVYV infect carrot in a field of Cipanas, Cianjur was the first report for the virus having host plant other than chili pepper. In this study, some surveys were conducted to elucidate the occurrence of PeVYV in carrot production centers of West Java. Some carrot plants showing RLD were collected from Cipanas (Cianjur), Lembang (West Bandung), and Cikajang (Garut). Based on reverse trancription-polymerase chain reaction analyses, it was found that PeVYV has been already occurred in the areas. The fact that all samples from Garut were infected by the virus suggest that PeVYV may first infected carrot plants in Garut, then spread to other areas of West Java. This is the first report concerning the distribution of PeVYV on carrot crops in West Java.
Keyword: RT-PCR., Production centres, Polerovirus, Distribution

Judul: Kloning dan Sequencing Gen Coat Protein Pepper vein yellow virus Penyebab Penyakit Daun Merah pada Tanaman Wortel
Abstrak: Pepper vein yellow virus (PeVYV) merupakan virus dengan kisaran inang terbatas pada cabai, namun untuk pertama kalinya dilaporkan menyebabkan penyakit daun merah (RLD) pada tanaman wortel di Jawa Barat. Gejala penyakit ini mirip dengan gejala infeksi Carrot motley dwarf yang diinduksi oleh spesies Polerovirus, yaitu Carrot red leaf virus. Tujuan dari penelitian ini adalah (1) untuk mengkloning gen coat protein (CP) virus ke dalam vektor plasmid untuk mempersiapkan antigen yang akan digunakan untuk produksi antiserum dan (2) untuk mengkonfirmasi bahwa virus yang terisolasi tersebut adalah PeVYV. Gen CP, berhasil disisipkan ke plasmid vektor pQE-30, sehingga dihasilkan fragmen DNA pQE-CP PeVYV. Kompeten sel Escherichia coli M15 (pREP) hasil transformasi berhasil ditumbuhkan pada media selektif yang mengandung ampicilin dan kanamicyn. Plasmid yang terdeteksi membawa gen CP berhasil diisolasi dari beberapa koloni bakteri yang tumbuh baik dengan teknik polymerase chain reaction maupun dengan penyisipan pada situs pemotongan BamHI dan PstI. Kloning gen CP ke dalam plasmid vektor telah berhasil dilakukan. Gen CP berhasil teramplifikasi hingga diperoleh panjang fragmen sebesar 650 bp, sesuai dengan gen CP Polerovirus yang telah dilaporkan di Genebank. Berdasarkan hasil analisis menggunakan Multiple alignment dengan software Crustal W, diperoleh tingkat homologi gen CP sebesar 98% dengan spesies PeVYV yang menginfeksi tanaman cabai di Bali. Hasil ini mengkonfirmasi bahwa RLD yang menginfeksi tanaman wortel berasosiasi dengan infeksi PeVYV, seperti laporan sebelumnya.
Keyword: Chimera, Escherichia coli M15 (pREP4), plasmid rekombinan pQE-CP PeVYV.

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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