The effect of explicit instruction and error correction on learners’ grammatical accuracy in the case of japanese learners of English as a second language

Este estudio afirma que la instrucción explicita (EI) con la corrección de error explicito (EEC) pueden ser eficaces para adquirir elementos lingüísticos que no se hayan enseñado lo suficiente y que mayormente expresen significado léxico. Por otra parte, EI con EEC no pueden ser eficaces para los elementos lingüísticos que mayormente expresen funciones gramaticales formales, que los aprendices ya conocen muy bien. El estudio asume que el orden linear fijo para algunos elementos (e. g., morfemas gramaticales) no es influenciado por estímulos externos (i. e. , EC con EEC): como L1, el proceso de la adquisición de la L2 no es al azar, sino ordenado. Sin embargo, el estudio no necesariamente niega el rol de la instrucción explicita del profesor para cada uno de los aspectos de la adquisición de la L2. El estudio también afirma que EI y EEC son más eficaces para aquellos aprendices quienes tengan sus niveles de competencia general de la L2 altos. Apoyamos estas suposiciones presentando tres experimentos con respecto a la adquisición de los sujetos de la oración y los morfemas gramaticales en inglés por japoneses adultos, aprendices del idioma Inglés.This study claims that explicit instruction (EI) with explicit error correction (EEC) can be effective for acquiring linguistic items which mainly convey lexical meaning, and have not been taught enough. On the other hand, EI with EEC cannot be effective for linguistic items which mainly convey formal grammatical functions, which are already well known to the learners. The study assumes that the fixed linear order for some grammatical items (e.g., grammatical morphemes) is not influenced by external stimuli (i.e., EC with EEC): Like L1, the L2 acquisition process is not random, but orderly. However, the study does not necessarily deny the role of teacher’s explicit instructions for every aspect of L2 acquisition. The study also claims that EI with EEC are more effective for those learners whose general L2 proficiency levels are high. We support these assumptions by presenting three experiments concerning the acquisition of English sentential subjects and grammatical morphemes by Japanese adult learners of English

Identification and characterization of structural proteins of orchid fleck virus

Orchid fleck virus (OFV) has a bipartite negative-sense RNA genome with sequence similarities to plant rhabdoviruses. The non-enveloped bullet-shaped particles of OFV are similar to those of the internal ribonucleoprotein (RNP)-M protein structure of rhabdoviruses, but they are about half the size of typical plant rhabdoviruses. Purified preparations contained intact bullet-shaped and filamentous particles. The filamentous particles showed a tightly coiled coil structure or a coiled structure with a helical twist, which resembles the RNP complex of rhabdoviruses. OFV bullet-shaped particles were structurally stable in solutions containing 2% Triton X-100 and 0.8 M NaCl. Western blot analyses revealed that the bullet-shaped particles contained N, P and M proteins, while filamentous particles contained mainly N and P proteins. In addition, a small amount of the L protein was detected in both types of particles. Thus, the structural proteins of OFV have properties similar to those of rhabdoviruses, except that the particles are non-enveloped and are relatively resistant to detergent-treatment under high-salt conditions

Orchid Fleck Virus: Brevipalpus californicus Mite Transmission, Biological Properties and Genome Structure

Orchid fleck virus (OFV) causes necrotic or chlorotic ring spots and fleck symptoms in many orchid species world-wide. The virus has non-enveloped, bacilliform particles of about 40 nm × 100–150 nm and is sap-transmissible to several plant species. OFV is transmitted by the mite Brevipalpus californicus (Banks) in a persistent manner and efficiently transmitted by both adults and nymphs, but not by larvae. Viruliferous mites retain their infectivity for 3 weeks on a virus-immune host. The genome of OFV consists of two molecules of 6431 (RNA1) and 6001 nucleotides (RNA2). The RNAs have conserved and complementary terminal sequences. RNA1 contains five open reading frames (ORF), and RNA2 encodes a single ORF. Although some of the encoded proteins of OFV have sequences similar to those of proteins of plant rhabdoviruses, OFV differs from viruses in the family Rhabdoviridae in having a bipartite genome

Detection of the Viruses Occurring in Oriental Cymbidium in Japan

A survey of virus diseases occurring in Oriental Cymbidium collected from a commerical nursery and home garden in Japan was conducted in 1991-1994. Identification of the vurus was based on partcle morphology, symptomatology in indicator plants, ultrastructure of infected cells and serology. Four viruses, odontoglossum ringspot tabamovirus(ORSV), cymbidium mosaic potexvirus(CyMV), orchid fleck virus (ORV) and a previously underscribed spherical virus, were found in 27 out of 37 Cymbidium plants tested. ORSV was detected from 11 plants belinging to Cym. ensifolium, Cym. forrestii, Cym. goeringii, Cym. kanran, Cym. sinense and Cymbidium spp. showing chlorotic streaks and/or mild mosaic. CyMV was isolated from only one plant of Cymbidium sp. showing mosaic and necrotic spots on leaves. In negatibvely stained dip preparations from plants infected with ORSV and CyMV, rod shaped particles of ca. 310 nm and flexuous rod-shaped ca. 475 nm in length were observed, respectively. The viruses were reacted strongly with respective antiserum to each virus in immunosorbent electron microcopy and inderect ELISA. OFV was isolated from four plants of Cym. formosanum, Cym. kanran, Cym. sinense and Cymbidium sp. showing mosaic and necrotic flecks. The virus had non-enveloped, bullet-shaped particles about 40×120～150 nm in dip preparation. The undescribed spherical virus, ca. 28 nm diameter, was isolated from 11 plants of Cym. forrestii, Cym. goeringii and Cymbidium spp. showing stunting and chlorotic streaks on newly developed leaves. The virus was mechanically transmitted only to Cymbidium orchids. Previously, we designated it as cymbidium chlorotic mosaic sobemovirus(CyCMV)(Kondo et al,1994),as the virus was considered to be a new member of the genus Sobemovirsu.1991～1994年にかけ山口県ならびに岡山県下を中心に東洋ラン（シンビジウム属）のウイルス病の発生調査を行った。ウイルス病様の症状を示していた37株の東洋ランを採集し、これらから病原ウイルスの分離、同定を試みた結果、オドントグロッサムリングスポットウイルス（ORSV）、シンビジウムモザイクウイルス（CyMV）、ランえそ斑紋ウイルス（OFV）ならびにソベモウイルス属の新ウイルスであるシュンラン退緑ウイルス（CyCMV）の発生が認められた。ORSVは退緑条斑や軽いモザイク症状を示すスルガラン、カンラン、コラン、ホウサイランなどから分離された。CyMVは明瞭なえそ斑を伴うモザイクを呈した東洋ラン（品種不祥、赤芽素心）から分離された。ORSVならびにCyMVに感染した植物のDN法試料中には電顕観察でそれぞれ長さ約310nmの棒状粒子と約475nmのひも状粒子が観察され、免疫電顕法と間接ELISA法では、これらのウイルスはそれぞれのウイルスに対する抗血清とよく反応した。OFVは退緑斑あるいはえそ斑点を生じているイトラン、カンラン、ホウサイランなどから検出された。その粒子形態は長さ約120～150nm、幅約40nmの被膜のない弾丸状あるいは桿菌状であった。CyCMVは新芽に明瞭な退緑斑や退緑状斑症状を示すシナシュンラン、シュンランなどから分離された。この球状ウイルスは直径約28nmで、シンビジウム属以外の植物には感染が認められなかった。今回の発生調査では、東洋ランからはORSVならびに新ウイルスのCyCMVがもっとも多く分離され、OFVは4株から、CyMVは1株から検出された。またこれらのウイルスによる重複感染は認められなかった

Cryphonectria nitschkei chrysovirus 1 with unique molecular features and a very narrow host range

Cryphonectria nitschkei chrysovirus 1 (CnCV1), was described earlier from an ascomycetous fungus, Cryphonectria nitschkei strain OB5/11, collected in Japan; its partial sequence was reported a decade ago. Complete sequencing of the four genomic dsRNA segments revealed molecular features similar to but distinct from previously reported members of the family Chrysoviridae. Unique features include the presence of a mini-cistron preceding the major large open reading frame in each genomic segment. Common features include the presence of CAA repeats in the 5′-untranslated regions and conserved terminal sequences. CnCV1-OB5/11 could be laterally transferred to C. nitschkei and its relatives C. radicalis and C. naterciae via coculturing, virion transfection and protoplast fusion, but not to fungal species other than the three species mentioned above, even within the genus Cryphonectria, suggesting a very narrow host range. Phenotypic comparison of a few sets of CnCV1-infected and -free isogenic strains showed symptomless infection in new hosts

Molecular Characterization of a Novel Polymycovirus From Penicillium janthinellum With a Focus on Its Genome-Associated PASrp

The genus Polymycovirus of the family Polymycoviridae accommodates fungal RNA viruses with different genomic segment numbers (four, five, or eight). It is suggested that four members form no true capsids and one forms filamentous virus particles enclosing double-stranded RNA (dsRNA). In both cases, viral dsRNA is associated with a viral protein termed "proline-alanine-serine-rich protein" (PASrp). These forms are assumed to be the infectious entity. However, the detailed molecular characteristics of PASrps remain unclear. Here, we identified a novel five-segmented polymycovirus, Penicillium janthinellum polymycovirus 1 (PjPmV1), and characterized its purified fraction form in detail. The PjPmV1 had five dsRNA segments associated with PASrp. Density gradient ultracentrifugation of the PASrp-associated PjPmV1 dsRNA revealed its uneven structure and a broad fractionation profile distinct from that of typical encapsidated viruses. Moreover, PjPmV1-PASrp interacted in vitro with various nucleic acids in a sequence-non-specific manner. These PjPmV1 features are discussed in view of the diversification of genomic segment numbers of the genus Polymycovirus

Biological and genetic diversity of plasmodiophorid-transmitted viruses and their vectors

About 20 species of viruses belonging to five genera, Benyvirus, Furovirus, Pecluvirus, Pomovirus and Bymovirus, are known to be transmitted by plasmodiophorids. These viruses have all positive-sense, single-stranded RNA genomes that consist of two to five RNA components. Three species of plasmodiophorids are recognized as vectors: Polymyxa graminis, P. betae, and Spongospora subterranea. The viruses can survive in soil within the long-lived resting spores of the vector. There are biological and genetic variations in both virus and vector species. Many of the viruses are causal agents of important diseases in major crops such as rice, wheat, barley, rye, sugar beet, potato, and groundnut. Control is dependent on the development of resistant cultivars. During the last half century, several virus diseases have rapidly spread worldwide. For six major virus diseases, we address their geographical distribution, diversity, and genetic resistance

Role of N-terminal His-rich Domain of Oscillatoria brevis Bxa1 in Both Ag(I)/Cu(I) and Cd(II)/Zn(II) Tolerance

A CPx-ATPase (named Bxa1) is induced in the cyanobacterium Oscillatoria brevis upon exposure to multiple heavy metal ions. The function of the bxa1 gene was examined by heterologous expression in both Saccharomyces cerevisiae (yeast) and Escherichia coli. Expression of bxa1 in E. coli caused Ag, Cd and Zn tolerance, but in yeast became sensitive to those metals. To reveal the role of the N-terminal His-rich domain (first 35 amino acids) of Bxa1, we constructed E. coli and yeast transformants carrying the bxa1 (Δ35bxa1). The E. coli transformant with Δ35bxa1 was sensitive to heavy metals. On the other hand, the yeast Δ35bxa1 transformant increased heavy-metal tolerance than bxa1 transformant. Fluorescence microscopy suggested that the two fusion proteins Bxa1::mGFP and Δ35Bxa1::mGFP are mainly localized in yeast endoplasmic reticulum (ER). These results imply that the function of Bxa1 was lost by the N-terminus deletion in both E. coli and yeast transformants. This is the first report that the His-rich domain in O. brevis Bxa1 is essential not only to monovalent (Ag+ and Cu+) but also to divalent (Cd2+ and Zn2+) heavy metal tolerance. Moreover, we clarified the toxicity mechanism against Cd using yeast transformants

A neo-virus lifestyle exhibited by a (+)ssRNA virus hosted in an unrelated dsRNA virus: Taxonomic and evolutionary considerations

Recent studies illustrate that fungi as virus hosts provides a unique platform for hunting viruses and exploring virus/virus and virus/host interactions. Such studies have revealed a number of as-yet-unreported viruses and virus/virus interactions. Among them is a unique intimate relationship between a (+)ssRNA virus, yado-kari virus (YkV1) and an unrelated dsRNA virus, yado-nushi virus (YnV1). YkV1 dsRNA, a replicated form of YkV1, and RNA-dependent RNA polymerase, are trans-encapsidated by the capsid protein of YnV1. While YnV1 can complete its replication cycle, YkV1 relies on YnV1 for its viability. We previously proposed a model in which YkV1 diverts YnV1 capsids as the replication sites. YkV1 is neither satellite virus nor satellite RNA, because YkV1 appears to encode functional RdRp and enhances YnV1 accumulation. This represents a unique mutualistic virus/virus interplay and similar relations in other virus/host fungus systems are detectable. We propose to establish the family Yadokariviridae that accommodates YkV1 and recently discovered viruses phylogenetically related to YkV1. This article overviews what is known and unknown about the YkV1/YnV1 interactions. Also discussed are the YnV1 Phytoreo_S7 and YkV1 2A-like domains that may have been captured via horizontal transfer during the course of evolution and are conserved across extant diverse RNA viruses. Lastly, evolutionary scenarios are envisioned for YkV1 and YnV1