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Characterization and comparison of passionfruit mottle virus, a newly recognized potyvirus, with passionfruit woodiness virus
No full textA virus, designated passionfruit mottle virus (PaMV), was isolated from plants of passionfruit cultivar Tainung No. 1, which showed mild mottling. Unlike the previously described passionfruit woodiness virus (PWV), PaMV does not induce severe foliage mosaic and woody, misshapen fruits. It was identified as a potyvirus on the basis of particle morphology, aphid transmissibility, and the ability to induce cytoplasmic cylindrical inclusions (CI) in infected cells. Of 25 plant species inoculated, 11 (Nicotiana benthamiana, four passiflora species, and six leguminous species) developed differential reactions. Two bean cultivars (i.e., Sutter pink and Dubbele witte) resistant to PWV were susceptible to PaMV, whereas another cultivar, Black turtle, which is resistant to PaMV, was systemically infected with PWV. PaMV induced bundle-shaped CIs in the cytoplasm of infected cells; PWV induced short platelike CIs. Purified virions and the cylindrical inclusion proteins (CIPs) of PaMV were obtained by isopycnic centrifugation and preparative electrophoresis, respectively. Antisera against intact virions and CIPs of PaMV and PWV were prepared for the comparison of antigenic properties. In reciprocal sodium dodecyl sulfate immunodiffusion tests and direct enzyme-linked immunosorbent assays, PaMV was shown to be antigenically related to, but distinct from, PWV, bean common mosaic, blackeye cowpea mosaic, watermelon mosaic 2, and soybean mosaic viruses, but was unrelated to 12 other potyviruses tested in the study
The success and drawbacks on the application of virus-free plant materials for control of plant virus diseases in the past three decades in Taiwan
No full text當作物感染系統性病原後無法以已知之方法加以治療，且病原可藉由寄主之無性繁殖而傳播至後代種苗。感病種苗不僅自身生長與品質低落，且形成病原傳播根源，造成病害之全面流行面對此類病害問題，栽培健康無病之種苗乃目前最廣為應用之防治策略。為生產大量健康無病種苗，常須規劃良好之繁殖體系才能達成。我國自1970年代初期即開始執行馬鈴薯健康種著繁殖制度，推行至今已愈24年，成效為各方肯定。其後20多年來本省陸續針對大蒜、柑橘、甘藷、香蕉、百香果、綠竹筍、甘蔗、草莓及豇豆之病毒病發展健康種苗繁殖制度，但未全部均達到預期之防治成效。本文乃回顧國內歷來發展健康種苗防治體系之實例，檢討每一個案所遭遇之瓶頸或成功之因素，希能藉此歸納成功之經驗，而規避可能之錯誤，以期能提供未來我國發展健康種苗之參考。
Plants infected by viruses or other systemic pathogens always suffer From reduction of growth, yield and quality and these effects usually last Generations for the pathogens can be transmitted through vegetative Propagation from mother plants to their offsprings. These diseases are in General impossible to be controlled by con ventional means such aschemical treatment. The infected seedlings or propagation materials serve as pathogen reservoir which is usually the main cause for the early outbreak of disease epidemic. The development of virus or pathogen-free propagation systems are always the first recommendation in the literature to solve these problems. In Taiwan, the first case for the virus-free plant propagation system was established in early 1970s to mass produce virus-free seed potatoes, which has been carrying out for more than 26 years and proved to be effective in controlling virus diseases of potato. Since the establishment of the virus-free seed potato system in Taiwan, there have been nine different crops implementing with pathogen-free propagation programs. However, some but not all the programs obtain satisfactory result on the disease control effect. This paper 15 to review the experience developed during the pathogen-free propagation programs conducted in Taiwan in the past 30 years and to summarize the advantages and/or shortcomings in each program. Hopefully, the conclusion will be beneficial to the development of Pathogen-free program that may be implemented for other crops in the future
Rugose mosaic of asparagus bean caused by dual infection with cucumber mosaic virus and blackeye cowpea mosaic virus
No full text夏季栽培之長豇豆普遍發生一種嚴重之毒素病，病株葉片出現皺葉嵌紋，分枝減少生育不良，開花及結實率顯著降低，豆莢捲曲變形且有壞疽現象，品質及產量均受嚴重之影響。利用煙草與菜豆可由病株中分離到兩種病毒，其中之一為球形顆粒病毒，根據．其寄主範圍與反應確定為胡瓜嵌紋病毒（Cucumber mosaic virus)，另一為長絲狀病毒，長度約為750 nm左右，依據其寄主範圍與反應以及血清學特性確定為黑眼豇豆嵌紋病毒（Blackeye cowpea mosaic virus）。二者分別感染長豇豆時並不產生皺葉嵌紋病徵，但是將兩病毒混合接種或前後接種，則可產生與田間病株完全相同的皺葉嵌紋病徵。在溫室管理之狀祝下單獨感染任一病毒之病株，其產量與品質與不接種對照之差異不顯著，但是複合感染病株則與對照達極顯著之差異。複合專染病株中兩病毒之濃度均較單獨感染時提高，提高的程度以CMV較顯著。利用單隻桃蚜可將複合病株中之CMV或BICMV以單獨或複合之狀態傳至健株，其總和傳播率較之以單獨惑染病株作傳染源時提高甚多，以上證據顯示兩病毒間發生相乘效應(synergism)導至長豇豆發生皺葉嵌紋病。
A virus disease of asparagus bean with severe rugose mosaic symptoms was found widespread in the field. Two viruses were isolated from the diseased plants using tobacco and kidney bean as filter hosts. The host reactions, physical properties in crude sap, particle morphology and transmission characteristics indicated that one of the two viruses was cucumber mosaic virus (CMV) while the other blackeye cowpea mosaic virus (BICMV). The BICMV isolate was also proved to be serologically identical with BICMV from the United States by SDS-immunodiffusion tests. When asparagus beans were inoculated by mechanical means or by aphid vectors with both CMV and
BICMV, simultaneously or in sequences, the leaves above the inoculated ones would show the rugose mosaic symptom, and the pods would develop abnormally and become necrotic at a late stage. However, when the test plants inoculated with virus singly, CMV caused only leaf mottling whereas B1CMV caused vein banding mosaic. Neither could cause abnormal pods. In the greenhouse, no differences were found in the growth, yield and quality of asparagus beans between plants inoculated with CMV or B1CMV singly and those of the healthy controls. On the contrary, the growth; yield and quality of plants doubly infected by CMV and B1CMV differed significantly from those of the healthy ones. The concentration of either virus in doubly infected plants was higher than in singly infected ones. Aphid transmission studies showed
that CMV and BICMV could be transmitted from doubly infected plants by one single aphid to cause single or dual infections in asparagus beans. The percentage of transmission from using doubly infected plants as virus sources was about two times greater than from using singly infected sources. These results suggest a synergistic effect between CMV and BICMV in asparagus beans
Characterization of a potyvirus causing mild mosaic on tuberose
No full textA virus inducing mild mosaic symptoms on the leaves and peduncles of tuberose (Polianthes tuberosa) was isolated and partially characterized. The isolate, designated Tbr1, could be transmitted mechanically and by green peach aphids (Myzus persicae) in a non-persistent manner to tuberose seedlings but not to 16 common assay species. Flexuous rod-shaped particles with a mean length of 750 nm could be easily seen in infected leaf dips and in purified samples. Cytoplasmic cylindrical inclusions, pinwheel and laminated aggregates similar to those assigned to potyviral cylindrical inclusion type II, were observed in infected tuberose leaves. The purified capsid contained a single species of protein monomer with an estimated relative mass of 38 kDa. In reciprocal sodium dodecyl sulfate-immunodiffusion tests, antiserum against Tbr1 reacted only with its homologous antigen but not with 22 different known potyviruses. Using primer pairs designed for potyvirus sequence amplification, a 2-kb DNA product equivalent to the estimated size for potyviruses was consistently amplified from purified Tbr1 virions or from crude infected tissue by reverse transcription polymerase chain reaction. On the basis of these results, Tbr1 was recognized as a unique species in the genus Potyvirus and hence designated as tuberose mild mosaic potyvirus (TMMV)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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