Judul: Identification and characterization of viruses infecting orchids in Java and induced systemic resistance of orchid using salicylic acid
Abstrak: Indonesia has a tremendous potency to develop orchid widely, due to the abundance of orchid germplasms. Several viruses infecting orchids were reported elsewhere. However, the presence of viruses infecting orchid in Indonesia is unknown. Thus, the aim of the researches were to identify viruses infecting orchids, its distribution in Java, its resistance response and to induced systemic resistance of susceptible orchid against Odontoglossum ringspot virus (ORSV) by using salicylic acid. Detection and identification of samples obtained from several survey locations by serological test and RT-PCR found that ORSV was detected mainly in samples from West Java (Taman anggrek Indonesia, Kebun Raya-Bogor, Gunung sindur- Bogor, Cianjur, Lembang). Cymbidium mosaic virus (CymMV) was detected mainly in central and East Java (Magelang, Malang, Surabaya). Cucumber mosaic virus (CMV), and Potyvirus were detected from all samples tested, however Tospovirus was undetectable from all samples by RT-PCR. Dual infection of ORSV and CymMV was found only in several samples from West Java. The nucleotide and amino acid sequences analysis of coat protein (CP) gene of six Java isolates of CymMV showed high homology with corresponding other 10 isolates elsewhere ranging from 95.8 to 98.8%, and 97.3 to 100%. The homology of nucleotide and amino acid sequences Java isolates of ORSV to other 11 isolates elsewhere ranging from 96.8 to 99.7% and 94.9 to 99.3%, respectively. These indicating that CymMV, ORSV, CMV and Potyvirus were present infecting orchids in Java, Indonesia. The ORSV could infect all indicator plants tested with incidence ranging from 60-100% and varied symptoms. The resistance response of 13 species of commercial orchids against ORSV showed that 61.54% of species was categorized as susceptible, and 38.46% was resistant based on type of symptoms, incubation period, disease incidence and virus accumulation. To increase the systemic resistance against ORSV infection, the susceptible orchid Dendrobium nindii was treated by using Salicylic acid (SA) on tissue culture media at concentration 1, 2, 4, 8, and 16 ppm. The SA on tissue culture media did not have any adverse effect on growth parameters and had decreased incidence, symptom expression and ORSV accumulation at concentration from 4-16 ppm. The SA treatment in plants at concentration 8-16 ppm increased total SA, and increased Phenylalanine ammonialyase (PAL) enzyme activity in compared with untreated plants. Among tested concentration, SA at concentration16 ppm was successfully able to increased D. nindii systemic resistance against ORSV with efficiency up to 93.75%. This is the first report of utilizing SA in orchid tissue culture media to increase systemic resistance against ORSV.
Keyword: CMV, Potyvirus, CymMV, ORSV, Induced systemic resistance, Salicylic acid, Phenylalanine ammonialyase, Viruses Infecting Orchids, Java

Judul: Deteksi dan karakterisasi Cymbidium Mosaic Virus (CymMV) isolat anggrek
Abstrak: Observation during field survey has proved that CymMV has infected orchid in West Java. The disease on orchid plants in Gunungsindur, Segunung, and Kebun Raya Bogor Districts was characterized by mosaic or chlorotic and necrotic sunken patches on the leaves. The objective of the research is to detect and characterize the virus causing mosaic or chlorotic and necrotic on orchids in West Java. Double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA) using antibody specific to CymMV successfully detected the virus in leaf tissues from symptomatic orchids plants. A reverse transcriptionpolymerase chain reaction (RT-PCR) assays using oligonucleotide primen specific to CymMV were also successfully amplified the regions of the coat protein (CP) gene of the virus. Analysis by using sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE) revealed that the virus have a major structural protein with an estimated molecdar weight of 28 kDa. Flexuous filamentous particles were also observed in electron microscopy preparations from infected plants and middle layer of purified virus preparation. Aliments of partial nucleotide sequences of the CP gene displayed 86 to 92% homology to CymMV isolates fiom other countries. The CymMV has an intermediate host range including plants belong to family of Orchidaceae, Solanaceae, Chenopodiaceae, Leguminosae, and Graminae.
Keyword: Orchids, Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE), Western blotting, Elektron mikroskopi

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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