147 resultados para Thielaviopsis paradoxa
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Geographically, Taiwan is an Island and situated in the northeast of Asia, on the western side of the Pacific Basin, at the southeast of main China, south of Japan, and north of the Philippines. The main topographic character is the longitudinally oriented mountainous area. More than 200 peaks rise above 3000 m. They departed Taiwan into two lowland areas, an eastern and western plain. Taiwan is departed into subtropical (north area) and tropical zone (south area), which have a warm and humid climate, due to the Tropic of Cancer passing through. The average annual temperature in the lowland amounts to 28°C (7~38°C). The temperate climate also presents in the mountainous areas. The tropical typhoons usually come in summer and bring heavy rain, while the monsoon seasons have an important effect on the regional rainfall distribution. The mean annual rainfall of Taiwan is about 2600 mm (1000~6700 mm); the mountainous areas receive more rain than the lowlands. In Taiwan, according to different temperature and vegetation, the ecological environments were given rise to vertical biotic zonations, and form five major types: highland snowfield, highland meadow, coniferous forest, deciduous forest, and tropical forest. Six National Parks in Taiwan are located in the mountainous areas, in the north, the south, and on Jinmen Island. The National Parks represent about 8.4% of the country area. In this study, the collection sites are situated in Yangmingshan, Shei-Pa, Yushan, and Kenting National Park. Due to the island isolation, the proportions of endemic species are great in Taiwan, which also presents a high biodiversity. There are 4255 species of vascular plants including 1133 endemic. 5936 species in 1276 genera of fungi are hitherto reported in Taiwan. Among them, 233 Corticiaceae species were recorded, over one third (79 species) of them are known only from Taiwan. The first fungal report in Taiwan is about Phytophthora cyperi, published by the Japanese researcher T. Kawakami in 1904. Therefore, the history of research about fungi in Taiwan is more than one hundred years old. An eminent Japanese mycologist K. Sawada made an intensive survey from 1919 to 1959, and reported 2464 fungi species in his eleven volumes of “Descriptive Catalogue of Formosan Fungi”. However, only a few species (21 species in 9 genera) of Corticiaceae were recorded. From 1973, Chen and Lin resumed the study on Corticiaceae, and also some other foreign mycologists contributed for this field after 1980. The German research group lead by Franz Oberwinkler from Tübingen University collected in Taiwan several times. They published a number of new species and new records. Since 1989, S. H. Wu, a Taiwanese mycologist, has published a great amount of reports on corticioid fungi from Taiwan. Corticioid fungi were made up by the large and heterogeneous unnatural family Corticiaceae and other resupinate fungi belonging to other natural families in the Agaricomycetes. Molecular studies have shown that corticioid genera are distributed across all major clades of Agaricomycetes indicating that the corticioid fungi represent a polyphyletic group. They have resupinate fruitbodies and similar habitats. Species are characterized by simple fruitbody, more or less effused, and present smooth, porioid, grandinioid to odontioid hymenial surface. The fruitbodies are differently colored and usually soft to tough. Most of the Corticiaceae species are wood-saprobic organisms and gain the energy from the decomposing of wood-substrate such as cellulose or lignin. Materials for this study were collected by the author and other mycologists in Taiwan during surveys in April and May 1996, and March 2007, using the spring season with its high humidity and warm climate which are optimal conditions for the development of fungi. For assembling, the convenience sampling method was used in this study. This approach was chosen because it enables to detect a high biodiversity in a short time, and also to find species with rare or patchy distribution. The collecting sites from the North to the South include four National Parks and some preserved forests. They cover many different habitats such as low lands and high mountains. Fresh specimens were dried and analysed with a light microscope. 265 specimens belonging to Corticiaceae were studied in this research. Among them, 50 species in 21 genera including 11 new records and 10 new species were described with text and drawing. Four new species are belonging to Hyphodontia (H. sp. nov. 1, H. sp. nov. 2, H. sp. nov. 3, and H. sp. nov. 4), four to Schizopora (Sch. sp. nov. 1, Sch. sp. nov. 2, Sch. sp. nov. 3, and Sch. sp. nov. 4), one in Trechispora (T. sp. nov. 1), and one in Tubulicrinis (T. sp. nov. 1). Species recorded as new are Aleurodiscus amorphus, Botryohypochnus isabellinus, Hyphodontia cineracea, Hyphodontia palmae, Hypochnicium vellereum, Merulius tremellosus, Metulodontia nivea, Paullicorticium ansatum, Phlebia radiata, Phlebiella ardosiaca, and Xylobolus frustulatus. Besides, Botryohypochnus, Merulius, Metulodontia, Paullicorticium, and Xylobolus are also newly recorded genera in Taiwan. The genus Hyphodontia presents the highest diversity with 20 out of 50 species recorded. The second important genus is Hyphoderma, however with only 5 species. This indicates that Hyphodontia and Hyphoderma have a higher ability to develop in variable environments and approximately shows the predominance of these two genera in Taiwanese Corticiaceae. There are 11 new records out of the 50 species recorded, representing 22%. Some species, e.g. Hypochnicium vellereum and Paullicorticium ansatum were in the past recorded only in Europe and North America with cold and temperate climate. The samples of them are for the first time found in the subtropical belt, and display some difference from those of temperate regions. These collections should be molecularly investigated to clarify if they represent the same species of temperate areas. Patchily distributed species, for example Phlebiella ardosiaca, previously known only in Europe, and Hyphodontia palmae collected only in Brazil, were first recorded in different continents. Two possibilities are indicated by these new records: they are worldwide species but very rare to be found, or the Taiwanese specimens are taxonomically different. More survey from other continents and molecular study for these collections should be done in the future to solve this question. The distribution of Corticiaceae in Taiwan presents the variations in the north, central, and south areas and shows the diversity in lowlands and high mountains. The results of this study provide the evidence that the temperate Corticiaceae species displays a wider distribution. Subtropical and tropical taxa probably have also high dispersal capacities, and could possibly be found in the future in neighboring areas such as China, Japan, Korea or South Asia, but this needs further researches. In the total of 50 species, 10 new taxa were described in this study, giving about 20%. Some new species (e.g. Hyphodontia sp. 1, Hyphodontia sp. 2, and Hyphodontia sp. 3) are very similar to known species (Hyphodontia sambuci and Hyphodontia formosana), and the distinctive characters of Schizopora sp. nov. 1 are intermediate between those of Schizopora paradoxa and Hyphodontia flavipora. Thus, these small differences between the new and known species, suggest that the speciation occurred when the fungi migrated into Taiwan, due to the high diversity of environment, and amounts of the endemic plants. Taiwan is an intermediate place for the south (tropical) fungal species to migrate and adapt to north (temperate) regions. The middle and high altitude environments in Taiwan offer good conditions for the fungal speciation and possibly the occurrence of physiological changes to adapt to the temperate climate. Thus Taiwan has an important position for the biogeography of Asia mycobiota. 5936 known species in Taiwan represent about only 20% of the estimated number (24000) of Taiwanese fungal taxa. In this study, the findings (22% new records and 20% new species) indicate that amounts of unknown fungi species are expected in Taiwan. The lack of knowledge indicates that many new species are awaiting description, and fungal survey in Taiwan remains in a Pioneer phase. The last three wide surveys of Corticiaceae researches took place 20 years before this study (Chen & Lin 1977, Lin & Chen 1989, Wu 1990). After previous important contributions, the present taxonomic study comprising 21 genera is the most extensive on Corticiaceae of Taiwan.
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Perennial plants are the main pollen and nectar sources for bees in the tropical areas where most of the annual flora are burned in dry seasons. Therefore perennial plants constitute the most reliable bio materials for determining and evaluating the beekeeping regions of the Republic of Benin. A silvo-melliferous region (S-MR) is a geographical area characterised by a particular set of homogenous melliferous plants that can produce timber. Using both the prevailing climatic and the agro-ecological conditions six S-MRs could be identified, i.e. the South region, the Common Central region, the Central West region, the Central North region, the Middle North region and the Extreme North region. At the country level, the melliferous plants were dominated by Vitellaria paradoxa which is common to all regions. The most diversified family was the Caesalpiniaceae (12 species) followed by the Combretaceae (10 species) and Combretum being the richest genus. The effect of dominance is particularly high in the South region where Elaeis guineensis alone represented 72.6% of the tree density and 140% of the total plant importance. The total melliferous plant density varied from 99.3 plants ha^(−1) in the Common Central region to 178.0 plants ha^(−1) in the Central West region. On the basis of nectar and pollen source, the best region for beekeeping is the CentralWest region with 46.7% of nectar producing trees, 9.4% of pollen producing trees and 40.6% of plants that issue both, this in opposition to the South region which was characterised by an unbalanced distribution of melliferous trees.
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La poesia és un genère literari que es veu sotmès a una paradoxa: per un costat, és ben valorat ocialment, ja que es considera que només la poden escriure uns "escollits" i també la poden llegir només els "iniciats". Però aquesta concepció genera una actitud en contra del mateix gènere: que ls que no es consideren "escollits" ni "iniciats" fàcilment se n'allunyen, de vegades de forma definitiva. Alguns del tòpics que des de sempre acompanyen la poesia poden ajudar a entendre questa actitud
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Bimodal dispersal probability distributions with characteristic distances differing by several orders of magnitude have been derived and favorably compared to observations by Nathan [Nature (London) 418, 409 (2002)]. For such bimodal kernels, we show that two-dimensional molecular dynamics computer simulations are unable to yield accurate front speeds. Analytically, the usual continuous-space random walks (CSRWs) are applied to two dimensions. We also introduce discrete-space random walks and use them to check the CSRW results (because of the inefficiency of the numerical simulations). The physical results reported are shown to predict front speeds high enough to possibly explain Reid's paradox of rapid tree migration. We also show that, for a time-ordered evolution equation, fronts are always slower in two dimensions than in one dimension and that this difference is important both for unimodal and for bimodal kernels
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Several species of the genus Rhipsalis (Cactaceae) are extremely important as ornamentals and are endangered in their natural habitat. However, only a few studies have addressed its taxonomy, morphology (including anatomy), phylogeny and evolutionary history. Consequently, the limited knowledge of the genus coupled with the problematic delimitation of species had led to problems in the identification of taxa. In the current work six species of Rhipsalis, R. cereoides, R. elliptica, R. grandiflora, R. paradoxa, R. pentaptera and R. teres were studied to evaluate the relevance of anatomical characters for the taxonomy of the genus. An anatomical characterization of the primary structure of the stem of Rhipsalis is provided highlighting the differences between species. Features of the stem epidermis are found to discriminate best between species and therefore provide clear and useful characters for the separation of species.
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The previous uncertain placement of Lysapsus and Pseudis within the neobatrachians was recently resolved by molecular and morphological studies, which supported them as members of the Hylinae subfamily. Their inter- and intrageneric relationships, however, have long been under debate and no studies shed light on these questions. Aiming to elucidate such questions, this paper used 3.2 kb comprising the mitochondrial genes 12S, tRNA valine, 16S and cytochrome b, and the nuclear exon 1 coding for rhodopsin, to all representatives of both genera (except to two subspecies of Pseudis paradoxa). The results identified three major clades: the clade 1 was composed by Lysapsus species and subspecies; clade 2 included the subspecies of the Pseudis paradoxa (Pseudis paradoxa paradoxa, P. paradoxa platensis and P. paradoxa occidentalis), P. fusca, P. bolbodactyla and P. tocantins, and clade 3 was composed by Pseudis southern Brazil species (Pseudis cardosoi and P. minuta). As closely related taxa we found Pseudis minuta + P. cardosoi; P. tocantins + P. fusca, and the subspecies within each genus. Evidence that Pseudis is not monophyletic with respect to Lysapsus was found and we suggest Lysapsus to be a junior synonym of Pseudis. Based on pair-wise comparison among gene sequences, we also suggest that the subspecies of Pseudis paradoxa and Lysapsus limellum must be considered as full species. (c) the Willi Hennig Society 2007.
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The present paper reports nuclear DNA content in 30 Neotropical freshwater fish species and summarizes the data on other Neotropical species presented in the literature. Among Neotropical fishes, the nuclear DNA content ranges from 1.04 ± 0.09 pg/nucleus in Corydoras cf. simulatus (2n = 62) to 248.0 pg/nucleus in Lepidosiren paradoxa (2n = 38). A general analysis of the data obtained in the present study for each species showed that DNA measurements were practically constant at the individual level, while significant differences were observed among individuals of the same population. This observation was valid for all species analyzed and was more evident in those species that presented other karyotypic particularities such as sex chromosomes or supernumerary chromosomes. The importance of changes in nuclear DNA content in the evolutionary process of Neotropical fishes is discussed.
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The objective of this work was to make a comparative analysis of germ cell organization at different stages of cellular differentiation in adult males of Dendropsophus nanus (Boulenger, 1889), Pseudis limellum (Cope, 1862), P. paradoxa (Linnaeus, 1758), and Scinax acuminatus (Cope, 1862), belonging to the family Hylidae; and Leptodactylus chaquensis (Cei, 1950) and L. podicipinus (Cope, 1862), belonging to the family Leptodactylidae, collected in the Pantanal and in Serra da Bodoquena, Mato Grosso do Sul State, Brazil. The testes were removed and fixed, dehydrated in a graded series of ethanol and embedded in methacrylate glycol resin (Historesin Leica®). The sections were stained by 1% toluidine blue and observed under light microscope. It was detected that all individual of the Hylidae family show, throughout the year, the presence of all germ cell types of spermatogenesis. However, all Leptodactylidae family individuals only show the presence of all germ cell types during the rainy season. The variations of characteristics in seminiferous epithelium organization, as well as the evident difference in the amount of spermatozoa inside the tubules, are evidence that the anurans in this work show different forms of spermatogenesis development throughout the year: the cycle is continuous for the Hylidae family, and discontinuous with explosive release of spermatozoa for the Leptodactylidae family.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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A helmintofauna tem papel central no ecossistema, pois afeta a ecologia, evolução, crescimento e regulação da população de hospedeiros e, consequentemente, toda a biodiversidade. Neste estudo foram selecionados anuros pertencentes a uma guilda, de acordo com o modo reprodutivo e sítio de vocalização, e foi estudada a supracomunidade de parasitas associadas a estes anfíbios. Em janeiro de 2009 foram coletados 60 anuros no Pantanal Sul- Matogrossense, sub-região Miranda-Abobral no município de Corumbá, MS. As espécies de anuros coletadas foram Rhinella granulosa, R. schineideri, Pseudis paradoxa, P. limellum, Pleurodema fuscomaculata e Physalaemus albonotatus. Os anuros foram necropsiados e analisados quanto à presença de helmintos. Dezesseis espécies de helmintos foram identificadas em 50 indivíduos hospedeiros (prevalência total = 83,3%). Dentre os parasitas foram encontradas três espécies de trematódeos (Catadiscus marinholutzi, Catadiscus propinquus e Glypthelmins palmipedis), uma espécie de cestoda, Cylindrotaenia americana, dez espécies de nematóides (Aplectana sp., Contracecum sp.,Cosmocerca podicipinus, Cosmocercidae, Falcaustra mascula, Physaloptera sp., Ochoterenella sp., Oswaldocruzia subauricularis, Physalopteroides venancioi sp. e Rhabdias sp.) e cistos de acantocéfalo. Os trematódeos foram encontrados apenas em P. paradoxa e P. albonotatus, enquanto C. americana foi encontrada apenas em P. fuscomaculata. As espécies Aplectana sp. e Falcaustra máscula foi encontrada apenas em R. schineideri. O único indivíduo encontrado em P. limellum foi da espécie Physalopteroides venancoi. As suprapopulações de parasitas se mostraram mais agregadas em R. granulosa e P. paradoxa, onde seus hábitos de vida e hábitos alimentares podem influenciar na comunidade parasitária. Logo o tamanho do hospedeiro pode influenciar na sua ...(Resumo completo, clicar acesso eletrônico abaixo)
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The sugarcane root endophyte Trichoderma virens 223 holds enormous potential as a sustainable alternative to chemical pesticides in the control of sugarcane diseases. Its efficacy as a biocontrol agent is thought to be associated with its production of chitinase enzymes, including N-acetyl-beta-D-glucosaminidases, chitobiosidases and endochitinases. We used targeted gene deletion and RNA-dependent gene silencing strategies to disrupt N-acetyl-beta-D-glucosaminidase and endochitinase activities of the fungus, and to determine their roles in the biocontrol of soil-borne plant pathogens. The loss of N-acetyl-beta-D-glucosaminidase activities was dispensable for biocontrol of the plurivorous damping-off pathogens Rhizoctonia solani and Sclerotinia sclerotiorum, and of the sugarcane pathogen Ceratocystis paradoxa, the causal agent of pineapple disease. Similarly, suppression of endochitinase activities had no effect on R. solani and S. sclerotiorum disease control, but had a pronounced effect on the ability of T. virens 223 to control pineapple disease. Our work demonstrates a critical requirement for T. virens 223 endochitinase activity in the biocontrol of C. paradoxa sugarcane disease, but not for general antagonism of other soil pathogens. This may reflect its lifestyle as a sugarcane root endophyte.
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Background: Sugarcane is one of the most important crops in Brazil, mainly because of its use in biofuel production. Recent studies have sought to determine the role of sugarcane endophytic microbial diversity in microorganism-plant interactions, and their biotechnological potential. Epicoccum nigrum is an important sugarcane endophytic fungus that has been associated with the biological control of phytopathogens, and the production of secondary metabolites. In spite of several studies carried out to define the better conditions to use E. nigrum in different crops, little is known about the establishment of an endophytic interaction, and its potential effects on plant physiology. Methodology/Principal Findings: We report an approach based on inoculation followed by re-isolation, molecular monitoring, microscopic analysis, plant growth responses to fungal colonization, and antimicrobial activity tests to study the basic aspects of the E. nigrum endophytic interaction with sugarcane, and the effects of colonization on plant physiology. The results indicate that E. nigrum was capable of increasing the root system biomass and producing compounds that inhibit the in vitro growth of sugarcane pathogens Fusarium verticillioides, Colletotrichum falcatum, Ceratocystis paradoxa, and Xanthomomas albilineans. In addition, E. nigrum preferentially colonizes the sugarcane surface and, occasionally, the endophytic environment. Conclusions/Significance: Our work demonstrates that E. nigrum has great potential for sugarcane crop application because it is capable of increasing the root system biomass and controlling pathogens. The study of the basic aspects of the interaction of E. nigrum with sugarcane demonstrated the facultative endophytism of E. nigrum and its preference for the phylloplane environment, which should be considered in future studies of biocontrol using this species. In addition, this work contributes to the knowledge of the interaction of this ubiquitous endophyte with the host plant, and also to a better use of microbial endophytes in agriculture.
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Symbiotische Mikroorganismen aus dem Termitendarm Es ist eine bekannte Tatsache, dass die Hauptaufgabe der Darmflora der niederen Termite im Abbau von Holz liegt. Im Laufe der Millionen Jahre alten Entwicklung der Termiten hat sich in ihrem Darm ein Ökosystem aufgebaut, das aus Protozoen, Archaeen, Bakterien und Hefen besteht. Ziel der vorliegenden Arbeit war die teilweise Erforschung der symbiotischen Zusammenhänge in diesem ökologischen System. Es wurden dabei zwei Gebiete genauer untersucht: Cellulolytische Bakterien im Darm von niederen Termiten Die bisher vorherrschende Meinung sah in den Protozoen die Hauptkomponenten des Celluloseabbaus in Termiten. In dieser Arbeit gelang es 164 cellulolytische Bakterienstämme aus sieben niederen Termitenarten zu isolieren und zu identifizieren. Diese Vielzahl cellulolytischer Bakterienarten könnte ein Indiz dafür sein, dass Bakterien beim Holzabbau von Termiten eine effizientere Rolle spielen als angenommen. Oberflächenbakterien von Mixotricha paradoxa, einem Flagellaten aus dem Darm der niederen Termite Mastotermes darwiniensisMixotricha paradoxa ist ein Beispiel der seltenen Form einer Bewegungssymbiose zwischen Protozoen und Bakterien. Der Flagellat wird von Spirochäten, die auf seiner Oberfläche befestigt sind, vorangetrieben. Zusätzlich leben noch stäbchenförmige Bakterien auf der Hülle. Drei Spirochätenarten und das stäbchenförmige Bakterium konnten identifiziert und lokalisiert werden. Es wird angenommen, dass alle drei Spirochätenarten Mitglieder der Bewegungssymbiose sind.