Deteksi Virus-Virus Pada Kentang Di Jawa Barat Dengan Menggunakan Teknik Molekuler

. Gejala infeksi virus ditemukan bervariasi di sentra pertanaman kentang di Jawa Barat (Rancabali, Pangalengan, dan Bayongbong). Diagnosis virus berdasarkan gejala sulit untuk menentukan identitas suatu virus. Oleh karena itu penelitian ini bertujuan mendeteksi virus-virus pada tanaman kentang dengan teknik molekuler. Sebanyak 50 sampel daun dikoleksi secara acak dari tanaman kentang yang bergejala di setiap lokasi. Parameter yang diamati adalah gejala, kejadian penyakit, dan runutan DNA virus yang dominan ditemukan. Kejadian penyakit ditentukan dengan uji serologi menggunakan antiserum PVY, PVX, PVS, dan CMV, sedangkan deteksi asam nukleat dilakukan dengan RT-PCR dan Perunutan DNA. Hasil penelitian menunjukkan bahwa gejala yang ditemukan bervariasi pada daun kentang, seperti vein clearing, vein banding, rugose, dan malformasi daun. Kejadian penyakit oleh PVY, PVX, PVS, dan CMV di Rancabali berturut-turut adalah 28%, 0%, 0%, dan 28%, di Pangalengan adalah 80%, 24%, 2%, dan 82%, serta di Bayongbong adalah 82%, 0%, 6%, dan 74%. RT-PCR menggunakan primer spesifik PVY dan CMV berhasil mengamplifikasi gen coat protein PVY dan CMV asal Bayongbong masing-masing berukuran ~800 pb dan ~650 pb. Homologi nukleotida dan asam amino PVY asal Bayongbong terhadap PVY dari negara lain berkisar 89,5–99,7% dan 92,0–100%. Homologi tertingginya yaitu dengan PVY-NTN asal Cina dan Jepang, sedangkan homologi nukleotida dan asam amino CMV asal Bayongbong terhadap CMV asal negara lain berkisar 87,6–96,9% dan 86,9–93,7%. Homologi tertingginya yaitu dengan CMV strain soybean stunt (S) asal Bogor (Indonesia). Kedua strain virus (PVY-NTN dan CMV-S) pertama kali terdeteksi pada kentang di Jawa Barat. Hasil penelitian menunjukkan bahwa teridentifikasinya kedua strain virus baru harus dipertimbangkan sebagai pembatas penting produksi kentang di Jawa Bara

Classification of metamorphic virus using n-grams signatures

Metamorphic virus has a capability to change, translate, and rewrite its own code once infected the system to bypass detection. The computer system then can be seriously damage by this undetected metamorphic virus. Due to this, it is very vital to design a metamorphic virus classification model that can detect this virus. This paper focused on detection of metamorphic virus using Term Frequency Inverse Document Frequency (TF-IDF) technique. This research was conducted using Second Generation virus dataset. The first step is the classification model to cluster the metamorphic virus using TF-IDF technique. Then, the virus cluster is evaluated using Naïve Bayes algorithm in terms of accuracy using performance metric. The types of virus classes and features are extracted from bi-gram assembly language. The result shows that the proposed model was able to classify metamorphic virus using TF-IDF with optimal number of virus class with average accuracy of 94.2%

Plaque formation and isolation of pure lines with poliomyelitis virus

Plaques have been produced with the three types of poliomyelitis viruses on monolayer tissue cultures of monkey kidney and monkey testis. The number of plaques was proportional to the concentration of the virus. Each plaque originates, therefore, from a single virus particle, defined as the virus unit that is unseparable by dilution. The plaques are due to the specific action of the virus since they are suppressed by type-specific antiserum. Pure virus lines were established by isolating the virus population produced in single plaques. These derived virus lines had the same morphological, serological, and pathogenic properties as the parent strain. High titer virus stocks, with titers up to 7 x 10^8 plaque-forming particles per ml., were obtained

Modification of H-2 Antigenic Sites by Enzymatic Treatment Influences Virus-Specific Target Cell Lysis

Vaccinia virus-infected cells were treated enzymatically to remove H-2 antigenic sites. The effect of this procedure on virus-specific cell-mediated cytolysis (CMC) and virus-specific antibody-mediated cytolysis (AMC) was tested. Due to the inhibition of cellular proteinsynthesis by the vaccinia virus infection, H-2 antigenic sites were not resynthesized while there was a continuous production of viral surface antigens. These cells with a high concentration of viral surface antigens and decreased H-2 determinants could be used as targets in the virus specific AMC. But they were not lysed in the virus specific CMC which emphasizes the significance of H-2 antigens during recognition of virus-specific determinants by T cells

Genetic Characterization of the Tick-Borne Orbiviruses

The International Committee for Taxonomy of Viruses (ICTV) recognizes four species of tick-borne orbiviruses (TBOs): Chenuda virus, Chobar Gorge virus, Wad Medani virus and Great Island virus (genus Orbivirus, family Reoviridae). Nucleotide (nt) and amino acid (aa) sequence comparisons provide a basis for orbivirus detection and classification, however full genome sequence data were only available for the Great Island virus species. We report representative genome-sequences for the three other TBO species (virus isolates: Chenuda virus (CNUV); Chobar Gorge virus (CGV) and Wad Medani virus (WMV)). Phylogenetic comparisons show that TBOs cluster separately from insect-borne orbiviruses (IBOs). CNUV, CGV, WMV and GIV share low level aa/nt identities with other orbiviruses, in 'conserved' Pol, T2 and T13 proteins/genes, identifying them as four distinct virus-species. The TBO genome segment encoding cell attachment, outer capsid protein 1 (OC1), is approximately half the size of the equivalent segment from insect-borne orbiviruses, helping to explain why tick-borne orbiviruses have a ~1 kb smaller genome

Effects of single and mixed infections with wild type and genetically modified Helicoverpa armigera nucleopolyhedrovirus on movement behaviour of cotton bollworm larvae

Naturally occurring insect viruses can modify the behaviour of infected insects and thereby modulate virus transmission. Modifications of the virus genome could alter these behavioural effects. We studied the distance moved and the position of virus-killed cadavers of fourth instars of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) infected with a wild-type genotype of H. armigera nucleopolyhedrovirus (HaSNPV) or with one of two recombinant genotypes of this virus on cotton plants. The behavioural effects of virus infection were examined both in larvae infected with a single virus genotype, and in larvae challenged with mixtures of the wild-type and one of the recombinant viruses. An egt-negative virus variant caused more rapid death and lower virus yield in fourth instars, but egt-deletion did not produce consistent behavioural effects over three experiments, two under controlled glasshouse conditions and one in field cages. A recombinant virus containing the AaIT-(Androctonus australis Hector) insect-selective toxin gene, which expresses a neurotoxin derived from a scorpion, caused faster death and cadavers were found lower down the plant than insects infected with unmodified virus. Larvae that died from mixed infections of the AaIT-expressing recombinant and the wild-type virus died at positions significantly lower, compared to infection with the pure wild-type viral strain. The results indicate that transmission of egt-negative variants of HaSNPV are likely to be affected by lower virus yield, but not by behavioural effects of egt gene deletion. By contrast, the AaIT recombinant will produce lower virus yields as well as modified behaviour, which together can contribute to reduced virus transmission under field conditions. In addition, larvae infected with both the wild-type virus and the toxin recombinant behaved as larvae infected with the toxin recombinant only, which might be a positive factor for the risk assessment of such toxin recombinants in the environment

Interactions between vaccinia virus and sensitized macrophages in vitro

The action of peritoneal exudate cells (PEC) from normal and vaccinia virus infected mice on infectious vaccinia virus particles was investigatedin vitro. PEC from immune mice showed a significantly higher infectivity titre reduction (virus clearance, VC) than normal cells. This effect could be clearly attributed to the macrophage. Vaccinia virus multiplied in PEC from normal animals while there was no virus propagation in cells from immunized mice. The release of adsorbed or engulfed virus was reduced significantly in PEC from immunized animals. Anti-vaccinia-antibodies seem to activate normal macrophages to increased virus clearance. This stimulating effect was demonstrable only in the IgG fraction of the antiserum. The activity of macrophages from mice injected three times over a period of 14 days with vaccinia virus could be entirely blocked with anti-mouse-IgG, while PEC from mice injected one time six days previously were not inhibited

Vertical transmission of honey bee viruses in a Belgian queen breeding program

Background: The Member States of European Union are encouraged to improve the general conditions for the production and marketing of apicultural products. In Belgium, programmes on the restocking of honey bee hives have run for many years. Overall, the success ratio of this queen breeding programme has been only around 50%. To tackle this low efficacy, we organized sanitary controls of the breeding queens in 2012 and 2014. Results: We found a high quantity of viruses, with more than 75% of the egg samples being infected with at least one virus. The most abundant viruses were Deformed Wing Virus and Sacbrood Virus (>= 40%), although Lake Sinai Virus and Acute Bee Paralysis Virus were also occasionally detected (between 10-30%). In addition, Aphid Lethal Paralysis Virus strain Brookings, Black Queen Cell Virus, Chronic Bee Paralysis Virus and Varroa destructor Macula-like Virus occurred at very low prevalences (<= 5%). Remarkably, we found Apis mellifera carnica bees to be less infected with Deformed Wing Virus than Buckfast bees ( p < 0.01), and also found them to have a lower average total number of infecting viruses ( p < 0.001). This is a significant finding, given that Deformed Wing Virus has earlier been shown to be a contributory factor to winter mortality and Colony Collapse Disorder. Moreover, negative-strand detection of Sacbrood Virus in eggs was demonstrated for the first time. Conclusions: High pathogen loads were observed in this sanitary control program. We documented for the first time vertical transmission of some viruses, as well as significant differences between two honey bee races in being affected by Deformed Wing Virus. Nevertheless, we could not demonstrate a correlation between the presence of viruses and queen breeding efficacies