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Caracterização morfológica de isolados de Colletotrichum sp., agente causal da antracnose em goiabeira-serrana (Acca sellowiana) (O. Berg.) Burret.
Full text linkDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Recursos Genéticos Vegetais, Florianópolis, 2013.A goiabeira-serrana (Acca sellowiana Berg) é uma frutífera pertencente à família das mirtáceas. Essa espécie está passando pelo processo de domesticação em seu centro de origem e diversidade. A antracnose é a principal doença da goiabeira-serrana no sul do Brasil e é causada pelo fungo Colletotrichum sp.. Este fungo pertence à classe dos Coelomycetes e se mostra como um dos principais fatores que limitam o cultivo de forma econômica dessa frutífera causando, em muitos casos, 100% de perda nos frutos de goiabeira-serrana. Sendo assim, o presente trabalho tem como objetivo diagnosticar a ocorrência de antracnose (Colletotrichum sp.) e caracterizar seu agente causal em goiabeira-serrana, procedente de distintas regiões de ocorrência natural e de cultivo no sul do Brasil. Nesse sentido, foram realizadas as etapas dos postulados de Koch, os testes de especificidade e patogenicidade, as análises culturais e caracterizados o índice de crescimento micelial, bem como o formato e as dimensões de conídios e apressórios de 45 isolados de Colletotrichum. Com o cumprimento de todas as fases dos postulados de Koch foi possível confirmar a real ocorrência de antracnose nos frutos de goiabeira-serrana e também, através obtenção da área abaixo da curva de progresso da doença (AACPD), verificar que os isolados de Colletotrichum apresentam diferentes níveis de patogenicidade, se comportam de maneira diferenciada de acordo com o a forma de inoculação e são capazes de infectar frutos de outras espécies (ex: macieira), mostrando que os mesmos não são patógenos específicos de goiabeira-serrana. O índice de crescimento micelial dos isolados variou de 5,1 mm/dia a 7,4 mm/dia. O comprimento (C) dos conídios variou de 13,7 µm a 18,8 µm, a largura (L) variou de 4,01 µm a 5,62 µm e a relação C/L dos mesmos variou de 2,5 a 4,1. A dimensão dos apressórios variou de 7,0 µm a 18,6 µm para comprimento, de 4,0 µm a 7,9 µm para largura e de 1,13 a 1,48 para relação C/L. Mesmo com a existência de uma grande zona de sobreposição dos valores para todas as características avaliadas, os dados encontrados se enquadram nos estimados para duas espécies do gênero Colletotrichum. Análises culturais como coloração, topografia, presença de setores, massa conidial, bem como formato e tamanho de conídios e apressório corroboraram com o enquadramento dos 45 isolados de Colletotrichum de goiabeira-serrana nos padrões estabelecidos para Colletotrichum gloeosporioides e Colletotrichum acutatum.Abstract : The feijoa (Acca sellowiana Berg) is a fruit belonging to the Myrtaceae family. This species is in the process of domestication in its center of origin and diversity. Anthracnose is a major disease of feijoa in southern Brazil and is caused by the fungus Colletotrichum sp.. This is a fungus that belongs to the family of Coelomycetes and it is one of the main factors that limit the economic exploitation of this fruit by causing, in many cases, loss of 100 % in the goiabeira-serrana fruit production. Thus, this study aims to diagnose the occurrence of anthracnose (Colletotrichum sp.) and characterize its causal agent in feijoa, coming from different naturally occurring regions and cultivation in southern Brazil. Accordingly, it was applied the steps of Koch's postulates, tested the isolates specificity and pathogenicity, analyzed the cultural features and characterized the mycelial growth rate, as well as the shape and size of conidia and appressoria of 45 Colletotrichum isolates. With the completion of all phases of Koch's postulates it was possible to confirm the actual occurrence of anthracnose in feijoa fruits. By obtaining the area under the disease progress curve (AUDPC), it was verified that the Colletotrichum isolates presented different levels of pathogenicity, behaved differently according to the inoculation method and the same Colletotrichum isolates are able to infect fruit of other species, indicating that they are not feijoa pathogen-specific. The rate of mycelial growth of the isolates ranged from 5.1 mm/day to 7.4 mm/day. The length (L) of the conidia ranged from 13.7 µm to 18.8 µm in width (W) ranging from 4.01 µm to 5.62 µm and the ratio L/W of the same ranged from 2.5 to 4.1. The size of appressoria varied from 7.0 µm to 18.6 µm for length, from 4.0 µm to 7.9 µm for width and 1.13 to 1.48 for the L/W. Even with the existence of a large overlap region for values of the all evaluated traits, the data obtained suggets that the isolates do fit in the two species of the genus Colletotrichum. Cultural analyzes as colony colour, topography, presence of sectors, conidial mass, as well as format and size of conidia and appressoria corroborate to frame the 45 Colletotrichum isolates from feijoa to the standards established for Colletotrichum gloeosporioides and Colletotrichum acutatum
Caracterização morfológica, filogenia e relação patógeno-hospedeiro de isolados de Colletotrichum associados à ocorrência de antracnose em feijoa [Acca sellowiana (O. Berg) Burret] no Sul do Brasil
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Recursos Genéticos Vegetais, Florianópolis, 2019.Feijoa ou goiabeira-serrana (Acca sellowiana O. Berg) é uma Myrtaceae que ocorre naturalmente no sul do Brasil e Uruguai. Esta espécie está passando pelo processo de domesticação em seu centro de origem e embora não seja amplamente conhecida, apresenta grande potencial econômico. O fungo fitopatogênico pertencente ao gênero Colletotrichum é o agente causal da antracnose, principal doença encontrada nos pomares dessa frutífera. Esse fungo pertence à classe dos Coelomycetes e, segundo relatos, pode causar até 100% de perda em pomares. Sendo assim, o presente trabalho tem como objetivo caracterizar, morfológico e geneticamente, o agente causal da antracnose em frutos de feijoa. A pesquisa visa, também, verificar a amplitude da sua gama de hospedeiros através da realização de inoculações cruzadas entre isolados e frutos de feijoa (Acca sellowiana), goiabeira comum (Psidium guajava), macieira (Malus domestica) das variedades Fuji e Gala e morangueiro (Fragaria ananassa). Os isolados de Colletotrichum foram coletados em 17 diferentes locais, nos estados de Santa Catarina (SC) e Rio Grande do Sul (RS), formando um conjunto de 40 colônias monospóricas. Para verificar os padrões morfológicos, dos isolados, foram analisadas características como: Índice de crescimento micelial (ICM), comprimento (C), largura (L), relação C/L e formato de conídios e apressórios. A análise filogenética multigênica foi baseada no sequenciamento de DNA de seis locos: espaçador interno transcrito (ITS) e genes Glyceraldehyde-3-fosfato- desidrogenase (GAPDH), calmodulina (CAL), actina sintase (ACT), quitina sintetase (CHS) e ß-tubulina 2 (TUB). Dados morfológicos mostraram que a taxa de crescimento micelial (mm / dia) das 40 colônias, variou de 7,5 mm / dia a 10,2 mm / dia; o comprimento dos conídios (C) variou de 13,8 µm a 19,4 µm; a largura (L) variou de 4,0 µm a 5,6 µm; e a relação C / L variou de 2,5 µm a 4,2 µm. O tamanho dos apressórios variou de 7,2 µm a 10,8 µm de comprimento; de 5,4 µm a 8,0 µm, para largura, e de 1,1 µm para 1,5 µm, para C / L. Os isolados produziram conídios cilíndricos ou fusiformes, e apressórios globulares, ovalados e irregulares. As análises filogenéticas multi-gene revelaram que os sintomas de antracnose observados, nos pomares e populações naturais de feijoa, são causados pelo fungo fitopatogênico da espécie Colletotrichum theobromicola. Os resultados morfológicos se alinharam à espécie descrita pelos dados moleculares. As inoculações cruzadas, visando conhecer a gama de hospedeiros da espécie C. theobromicola, obtiveram maior sucesso na infecção de frutos perfurados do que em frutos não perfurados, de todas as espécies frutíferas testadas. Adicionalmente, isolados destas três espécies, inoculados em frutos de feijoa também conseguiram causar infecção, independentemente do método de inoculação. Estas conclusões, juntamente com dados sobre o estilo de vida dos isolados, permitirão maiores e melhores inferências sobre o estabelecimento e manejo de pomares comerciais. Resultados como os obtidos nessa pesquisa, também se mostram importante do que diz respeito ao estabelecimento de programas de melhoramento genético, controle de doenças e atividades de biovigilância.Abstract: The feijoa or pineapple-guava (Acca sellowiana Berg), goiabeira-serrana in portuguese, is a fruit belonging to the Myrtaceae family, with natural occurrence in south of Brazil and Uruguay. This specie is in domestication process in its origin and diversity center. Anthracnose is the biggest feijoa disease in southern Brazil and is caused by the genus fungus Colletotrichum. This fungus belongs to the Coelomycetes class and it is one of the main factors that limit the commercial exploitation of feijoa fruit, causing in many cases, loss of 100 % in orchards. Thus, the present work intend to characterize, morphologically and genetically, the anthracnose causal agente in feijoa fruit. The research also wants to verify the amplitude of its host range by performing cross-inoculations between isolates and fruits of feijoa (Acca sellowiana), common guava (Psidium guajava), apple (Malus domestica) of Fuji and Gala varieties and strawberry (Fragaria ananassa). Colletotrichum isolates were collected from 17 different sites in the Santa Catarina state (SC) and Rio Grande do Sul state (RS), forming a set of 40 monosporic colonies. To verify the isolates morphological patterns, characteristics were analyzed as: mycelial growth index (ICM), length (C), width (L), C / L ratio and conidia and appressorium shape. Multigenic phylogenetic analysis was based on DNA sequencing of six loci: transcribed internal spacer (ITS) and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), actin synthase (ACT), chitin synthetase (CHS) and ß-tubulin 2 (TUB). Morphological data showed that the mycelial growth rate (mm / day) of the 40 colonies ranged from 7.5 mm / day to 10.2 mm / day; the length of conidia (C) ranged from 13.8 µm to 19.4 µm; the width (L) ranged from 4.0 µm to 5.6 µm; and the C / L ratio ranged from 2.5 µm to 4.2 µm. The appressoria size ranged from 7,2 µm to 10,8 µm in length; from 5.4 µm to 8.0 µm for width and from 1.1 µm to 1.5 µm for C / L. The isolates produced cylindrical or fusiform conidia and globules, nailed and irregular appressories. Multi-gene phylogenetic analyzes revealed that the anthracnose symptoms observed in orchards and natural feijoa populations are caused by the phytopathogenic fungus Colletotrichum theobromicola specie. The morphological results aligned with the species described by the molecular data. The cross inoculations to know the host range of C. theobromicola species, were more successful in the infection of perforated fruits than in non-perforated fruits of all tested fruit species. Additionally, isolates of these three species inoculated in feijoa fruits also caused infection, regardless of the inoculation method. These findings, together with lifestyle data from the isolates, will allow for greater and better inferences about the establishment and management of commercial orchards. Results such as those obtained in this research are also important regarding the establishment of genetic improvement programs, disease control and biovigilance activities
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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