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: Elimination of Cymbidium mosaic virus on Dendrobium Plbs Orchid by Using Ribavirin as Antiviral Agent
Abstrak: Orchid is an ornamental plant that has a fairly high level of demand and ranked first compared to other ornamental plants. The beauty of orchid plants can be reduced if infected by pathogenic virus like Cymbidium mosaic virus (CyMV). CyMV is the one of the dominant pathogen infecting orchid plant in the world. Detection of CyMV infection can be performed by DAS-ELISA (Double Antibody Sandwich - Enzyme Linked Immunosorbent Assay) method. To further confirm, it can be distinguished the pattern of CyMV protein bands by using composite gel electrophoresis method. The aims of this study to determine the optimum concentration of Ribavirin antiviral agent on CyMV elimination in Dendrobium Jayakarta protocorm-like bodies (plbs) and to distinguish the patterns of protein bands of healthy Dendrobium plants or CyMV free plbs and the infected ones. Stages of this study included to detect CyMV in Dendrobium plbs, infected plbs propagation in Vacin and Went liquid media, to eliminate CyMV by Ribavirin antiviral treatments in six concentrations (0, 10, 20, 30, 40 and 50 ppm) arranged in Randomized Completely Design with three replications and to distinguish the CyMV protein banding pattern by using composite gel electrophoresis method. The results of this study showed that CyMV was eliminated by Ribavirin in D. Jayakarta plbs. The optimum concentration of Ribavirin to eliminate 100% CyMV without growth inhibition of the plbs was 30 ppm. The result of CyMV protein banding pattern analysis by composite gel electrophoresis method showed that CyMV infected plant and plbs had one band with molecular weight approximately 28 kDa. There was no band on healthy or CyMV free Dendrobium plant and D. Jayakarta plbs.
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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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