A study of the economic impacts of the TPP on Korea: Armington and Melitz model

Purpose – The purpose of this paper is to measure the effects of TPP on Korean economy focussing on the changes in the number of firms and productivity. Design/methodology/approach – Following Melitz (2003) and Balistreri et al. (2011), the authors apply CGE simulation to five groups of 140 countries. Findings – The authors find that welfare increases in Korea to join the TPP regardless the size of the TPP through productivity improvement of participating firms and increases in the number of exporting firms, factor prices and outputs. Practical implications – This study helps tentative member countries of TPP decide to join. Originality/value – The effects of TPP to Korean economy is measured with Melitz model, which has not yet attempted before.

First Report of Grapevine Virus Sequences Highly Similar to Grapevine Syrah virus-1 from Washington Vineyards

Grapevine Syrah virus-1 (GSyV-1), a tentative member of the genus Marafivirus in the family Tymoviridae, has recently been found in a declining Syrah grapevine in California vineyards (1). To determine if GSyV-1 is present in grapevines grown in Washington State vineyards, extracts prepared from individual grapevines of six cultivars (Merlot, Chardonnay, Pinot Noir, Lemberger, Cabernet Sauvignon, and Syrah/Shiraz) were tested by single-tube reverse transcription (RT)-PCR using the primer pair GSyV-1 Det-F (5′-CAAGCCATCCGTGCATCTGG-3′) and GSyV-1 Det-R (5′-GCCGATTTGGAACCCGATGG-3′). The primer GSyV-1 Det-F is identical to nucleotides (nt) 1125 to 1144 and GSyV-1 Det-R complementary to nt 1401 to 1420 of the GSyV-1 genome (GenBank Accession No. NC_012484) in the putative movement protein encoding gene (1). DNA fragment of approximately 296 base pairs (bp) was amplified only from 7 of 60 and 2 of 20 individual grapevines of cv. Syrah/Shiraz and Chardonnay, respectively, obtained from geographically separate vineyards. The 296-bp fragments from three Syrah/Shiraz and two Chardonnay grapevines were cloned individually into the pCR2.1 plasmid (Invitrogen Corp., Carlsbad, CA). Three independent clones derived from each DNA fragment were sequenced from both orientations and the sequences edited and assembled using ContigExpress project in the Vector NTI Advance 11 sequence analysis software packages (Invitrogen). Pairwise comparison of four of these sequences (Accession Nos. GU372349–52) showed 99 to 100% amino acid (aa) sequence identity among themselves and with corresponding sequences of GSyV-1. Because of the lack of antibodies, an additional 611-bp fragment specific to the capsid protein (CP) gene of GSyV-1 was amplified from six isolates (five from cv. Syrah/Shiraz, and one from cv. Chardonnay) (Accession Nos. GU372353–66) using primers GSyV-1-F (5′-TGTCGACGCTCCAATGTCTGA-3′) and GSyV-1-R (5′-CATTGCTGCGCTTTGGAGGCTTTA-3′). GSyV-1-F is identical to nt 5775 to 5795 and GSyV-1-R is complementary to nt 6385 to 6408 of the GSyV-1 genome. The amplicons were cloned and sequenced as described above. Comparison of these sequences among themselves and with corresponding sequences of GSyV-1 showed 96 to 99% aa sequence identity, further complementing the results obtained above. To our knowledge, this is the first report of the occurrence of viral sequences closely related to GSyV-1 in Washington vineyards. Together with other reports (1,2), this study suggests that viruses similar to GSyV-1 could be widely distributed in wine grape cultivars across grape-growing regions. References: (1) M. Rwahnih et al. Virology 387:395, 2009. (2) S. Sabanadzovic. Virology 394:1, 2009.

Isolation of a novel species of flavivirus and a new strain of Culex flavivirus (Flaviviridae) from a natural mosquito population in Uganda

The genus Flavivirus, which contains approximately 70 single-stranded, positive-sense RNA viruses, represents a unique model for studying the evolution of vector-borne disease, as it includes viruses that are mosquito-borne, tick-borne or have no known vector. Both theoretical work and field studies suggest the existence of a large number of undiscovered flaviviruses. Recently, the first isolation of cell fusing agent virus (CFAV) was reported from a natural mosquito population in Puerto Rico, and sequences related to CFAV have been discovered in mosquitoes from Thailand. CFAV had previously been isolated from a mosquito cell line in 1975 and represented the only known ‘insect-only’ flavivirus, appearing to replicate in insect cells alone. A second member of the ‘insect-only’ group, Kamiti River virus (KRV), was isolated from Kenyan mosquitoes in 2003. A third tentative member of the ‘insect-only’ group, Culex flavivirus (CxFV), was first isolated in 2007 from Japan and further strains have subsequently been reported from the Americas. We report the discovery, isolation and characterization of two novel ‘insect-only’ flaviviruses from Entebbe, Uganda: a novel lineage tentatively designated Nakiwogo virus (NAKV) and a new strain of CxFV. The individual mosquitoes from which these strains were isolated, identified retrospectively by using a reference molecular phylogeny generated using voucher specimens from the region, were Mansonia africana nigerrima and Culex quinquefasciatus, respectively. This represents the first isolation, to our knowledge, of a novel insect-only flavivirus from a Mansonia species and the first isolation of a strain of CxFV from Africa.

Potyvirus Complexes in Sweetpotato: Occurrence in Australia, Serological and Molecular Resolution, and Analysis of the Sweet potato virus 2 (SPV2) Component

A survey for viruses in sweetpotato revealed the presence of Sweet potato virus 2 (SPV2; synonymous to Sweet potato virus Y and Ipomoea vein mosaic virus), a tentative member of the genus Potyvirus, for the first time in Australia. The SPV2-infected sweetpotato plants were also infected with strains RC and/or C of Sweet potato feathery mottle virus (SPFMV; genus Potyvirus). Five SPV2 and SPFMV isolates from Australia were sequence-characterized at the 3′ - proximal end (ca. 1.8 kb) of the genome. A simple and sensitive diagnostic procedure was devised to readily differentiate SPV2 and the two strains of SPFMV from sweetpotato plants that contained these viruses in complexes. The method involved reverse transcription with oligoT25 primer, polymerase chain reaction using a combination of degenerate primers, and restriction analysis of the 1.8-kb amplification products with HindIII and PvuII endonucleases. The Nproximal 543 nucleotides of the SPV2 coat protein-encoding sequence of the Australian isolates and 14 other isolates from Asia, Africa, Europe, and North America were subjected to phylogenetic analysis. The Australian SPV2 isolates formed a separate clade that was closest to a clade containing two North American isolates.

Development of a Molecular Tool for the Diagnosis of Leprosis, a Major Threat to Citrus Production in the Americas

Citrus leprosis virus (CiLV), a tentative member of the Rhabdoviridae family, affects citrus trees in Brazil, where it is transmitted by mites Brevipalpus spp. It also occurs in other South American countries and was recently identified in Central America. This northbound spread of CiLV is being considered a serious threat to the citrus industry of the United States. However, despite its importance, difficulties related to the biology of CiLV have hindered much of the progress regarding its accurate detection, leaving both the analyses of symptoms and electron microscopy as the only tools available. An attempt to overcome this problem was made by constructing a cDNA library from double-stranded RNA extracted from leprosis lesions of infected Citrus sinensis (sweet orange) leaves. After cloning and sequencing, specific primers were designed to amplify putative CiLV genome regions with similarity to genes encoding the movement protein and replicase of other plant viruses. RNA from infected citrus plants corresponding to different varieties and locations were amplified by reverse transcription-polymerase chain reaction (RT-PCR) using the two pairs of primers. Amplified products were purified, cloned in pGEM-T, and sequenced. The sequences confirmed the genomic regions previously associated with CiLV. The results demonstrate that RT-PCR was specific, accurate, rapid, and reliable for the detection of CiLV.

Characterization and complete nucleotide sequence of Strawberry mottle virus: a tentative member of a new family of bipartite plant picorna-like viruses

An isolate of Strawberry mottle virus (SMoV) was transferred from Fragaria vesca to Nicotiana occidentalis and Chenopodium quinoa by mechanical inoculation. Electron micrographs of infected tissues showed the presence of isometric particles of approximately 28 nm in diameter. SMoV-associated tubular structures were also conspicuous, particularly in the plasmodesmata of C. quinoa. DsRNA extraction of SMoV-infected N. occidentalis yielded two bands of 6·3 and 7·8 kbp which were cloned and sequenced. Gaps in the sequence, including the 5′ and 3′ ends, were filled using RT–PCR and RACE. The genome of SMoV was found to consist of RNA1 and RNA2 of 7036 and 5619 nt, respectively, excluding a poly(A) tail. Each RNA encodes one polyprotein and has a 3′ non-coding region of ∼1150 nt. The polyprotein of RNA1 contains regions with identities to helicase, viral genome-linked protein, protease and polymerase (RdRp), and shares its closest similarity with RNA1 of the tentative nepovirus Satsuma dwarf virus (SDV). The polyprotein of RNA2 displayed some similarity to the large coat protein domain of SDV and related viruses. Phylogenetic analysis of the RdRp region showed that SMoV falls into a separate group containing SDV, Apple latent spherical virus, Naval orange infectious mottling virus and Rice tungro spherical virus. Given the size of RNA2 and the presence of a long 3′ non-coding region, SMoV is more typical of a nepovirus, although atypically for a nepovirus it is aphid transmissible. We propose that SMoV is a tentative member of an SDV-like lineage of picorna-like viruses.

Activities associated with the putative replication initiation protein of Coconut foliar decay virus, a tentative member of the genus Nanovirus

The putative replication initiation protein (Rep) of Coconut foliar decay virus (CFDV) was expressed as a 6× His recombinant protein in E. coli and in recombinant baculovirus. Purified 6× His–Rep protein was demonstrated to possess sequence non-specific RNA- and ssDNA-binding activities as well as magnesium-dependent ATPase/GTPase activity. The yeast two-hybrid system revealed that CFDV Rep could interact with itself. Subcellular distribution of the CFDV Rep was studied by fractionation of insect cells infected with recombinant baculovirus expressing the 6× His–Rep protein and by laser scanning confocal microscopy of Nicotiana benthamiana epidermal cells bombarded with a construct encoding CFDV Rep fused to GFP. It was shown that CFDV Rep associated predominantly with nuclei and membranes of infected/transfected cells. These activities of CFDV-encoded Rep are very similar to those reported for Reps of geminiviruses.

Cytological and molecular evidence that the whitefly-transmitted Cucumber vein yellowing virus is a tentative member of the family Potyviridae

Cucumber vein yellowing virus (CVYV) is widespread in cucurbits in the Middle East. CVYV has filamentous particles and is transmitted by Bemisia tabaci by the semi-persistent mode. It has not yet been assigned to a specific genus or family. Ultramicroscopic observations revealed numerous cylindrical cytoplasmic inclusions in melon and cucumber cells infected by CVYV isolates from Israel and Jordan. Depending on the section orientation, the inclusions appeared as pinwheels or as bundles. In addition, a 1·9 kb DNA fragment was amplified by RT–PCR from CVYV-infected plant extracts using primers designed to detect all potyvirids. Sequence comparisons with the amplified fragment indicated that CVYV is more closely related to Sweet potato mild mottle virus than to any other virus in the family Potyviridae. These results suggest that CVYV can be considered as a tentative new member of the genus Ipomovirus, family Potyviridae.