362 research outputs found

    Endo- and epiphytic fungal communities of olive twigs is influenced by cultivar and olive knot infection

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    Olive tree phyllosphere is colonized by a diverse microbial assemblage that may interact with pathogenic fungi, making them potential candidates for disease supression. Olive knot (OK) is a disease caused by the bacterium Pseudomonas savastanoi pv. savastanoi (Psv.) with significant economic losses in olive tree (Olea europaea L.). With this work we want to evaluate the effect of cultivar and OK infection on both endo- and epiphytic fungal community inhabiting olive twig tissues. For this, fungal composition and diversity was assessed in both asymptomatic and OK-symptomatic twigs of tree co-occurring olive cultivars with different susceptibilities to OK disease. The identification of isolated species was performed by ITS rDNA sequencing. The cultivar and OK infection were important in shaping both endophytic and epiphytic fungal communities. Fungal community composition was found to differ significantly (p=0.005) between olive tree cultivars, being Nectriaceae the dominant family in cvs. Cobrançosa and Verdeal Transmontana, whereas Pleosporaceae was dominant in the cv. Madural. Epiphytic and endophytic fungal communities also differed in size and in composition in asymptomatic and OK-symptomatic twigs, for the three cultivars. In general, asymptomatic twigs were more diverse and rich (up to 1.4-fold) when compared to OK-symptomatic twigs. Among the species identified in the asymptomatic tissues, Cladosporium cladosporioides and Chromelosporium carneum were the most frequently isolated within epiphytic and endophytic community, respectively; whereas in the OK-symptomatic tissues Cladosporium sp. and Fusarium lateritium were the most frequently isolated within epiphytic and endophytic community, respectively. According to indicator species analysis C. carneum, Pyronema dosmesticum and Phoma aloes (IndVal up to 0.56) may be promising species in the OK suppression. Better acknowledgement should be developed in order to uncover their role on plant health.FEDER funds through COMPETE (Programa Operacional Factores de Competitividade} and by national funds by FCT [Fundação para a Ciência e a Tecnologia) in the framework of the project EXCL/AGR-PRO/0591/2012. T. Gomes thanks FCT, POPH-QREN and FSE for PhD SFRH/BD/98127/2013 Grantinfo:eu-repo/semantics/publishedVersio

    Efeito de extractos de raízes eliciadas de Castanea sativa no crescimento do fungo ectomicorrízico Pisolithus tinctorius

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    O castanheiro (Castanea sativa Mill.) estabelece associação com numerosas espécies de fungos ectomicorrízicos, estando descritos os efeitos benéficos para a planta após micorrização com Pisolithus tinctorius. Neste processo é essencial que ocorra a troca de sinais entre os simbiontes, para que seja reconhecida a sua compatibilidade e para que ocorra a formação dos órgãos ectomicorrízicos. Neste trabalho são fornecidas evidências que sugerem a capacidade de extractos de raízes de castanheiro, nos estádios iniciais de contacto com P. tinctorius regularem o crescimento do fungo micorrízico

    Screening for angiotensin I-converting enzyme (ACE) inhibitory activity of enzymatic hydrolysates obtained from Azorean macroalgae

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    As part of ongoing studies into the isolation of antihypertensive peptides, 12 common macroalgae species from Azores were investigated for their potential angiotensinconverting enzyme (ACE) inhibitory properties. After optimization of enzymatic hydrolysis conditions, the anti-ACE activity was determined by high performance liquid chromatography (HPLC). The species under study include four Rhodophyta (Gelidium microdon, Osmundea pinnatifida, Porphyra sp. and Pterocladiella capillacea), four Chlorophyta (Chaetomorpha linum, Codium adhaerens, Ulva compressa and Ulva rigida) and four Heterokontophyta (Cystoseira humilis, Fucus spiralis, Padina pavonica and Sargassum cymosum). The bromelain hydrolysates derived from P. capillacea, Porphyra sp., F. spiralis, U. compressa, O. pinnatifida and U. rigida were the most active presenting an ACE inhibitory activity of 48.73 ± 1.58%, 50.96 ± 1.82%, 56.77 ± 1.80%, 59.80 ± 0.95%, 62.59 ± 1.60% and 65.68 ± 0.72%, respectively. These results suggest that some macroalgae from the littoral Azorean sea are potential sources of powerful ACE inhibitor peptides, with potential impact on public health, particularly on the hypertensive patients. These features make these algae valuable to the regional economy and may also provide an incentive for marine biodiversity conservation and valuation of marine algal resources

    Barcoding of entomopathogenic fungi from olive tree pests : prospects and limitations

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    From all the barcoding initiatives in progress, fungal barcode is probably the one where more difficulties have been encountered. While for plants and animais the barcode regions were easy to define, for fungi the choice was not so straightforward. The internal transcribed spacer (ITS) region was one of the proposed DNA regions for barcoding fungi. This is an extensively used region, for molecular systematic and identification of species, being probably the most widely sequenced DNA region of fungi. This is due to the simplicity of the amplification, related to the multicopy nature of the rDNA; the possibility of using universal primers; and the high levei of sequence variation that occurs even between closely related species. Furthermore, a significant number of identified sequences for comparison are available in the GenBank database. Although the ITS region of rDNA was chosen for some groups of fungi, the use of this region presents very limited application for others, especially for Ascomycetes. As some of the most important entomopathogenic fungi are Ascomycetes, belonging to genera Beauveria, Cordyceps, Isaria, Lecanicillium and Paecilomyces, the use of the ITS region for barcoding purpose are being complemented with other regions. This work, based on the identification of fungal entomopathogens isolated directly from cadavers of one of the major pests in olive graves, the olive moth iPrevs oleae Bern.), intends to illustrate the application of the ITS region to identify these fungal species. The use of this region proved to be useful for the identification of most of the entomopathogenic fungi found in dead larvae and pupae of P. oleae. However, the use ot ITS region for barcode purposes did not allow the identification of several isolates, proving the requiremerít of using a second barcoding region, to enable full fungal identification.This work has been supported by FCT (PTDC/AGR-AAM/02600/2008)

    Identification of fungi isolated from the olive moth (Prays oleae Bern.) based on ITS region

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    Fundação para a Ciência e Tecnologia (FCT) - Project PTDC/AGR-AAM/102600/200

    Fungal diversity among different annual generations of Prays oleae

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    Comunicação em painelThe olives and olive oil production are important agricultural activities in Portugal. In the region of Trás-os-Montes, olive orchards are strongly affected by Prays oleae Bern., which is responsible for high losses in the olive production, as much as 40% of the expected yield. This lepidopteran presents three generations per year (phyllophagous, antophagous and carpophagous) that damage the olive tree in different organs (leaves, flowers and fruits, respectively). In an attempt to identify fungi that might cause the death of olive moths, larvae and pupae of those three annual generations were collected and surveyed for natural fungal infection. After their isolation, the fungal agents were molecularly identified by sequencing the amplified internal transcribed spacer (ITS) region of rDNA. In the present work, the diversity of fungal species associated to P. oleae, in several olive orchards located in Trás-os-Montes region, is discussed. The diversity and abundance of fungal species differed between all three generations. Higher diversity was found in the carpophagous generation, followed by the antophagous and phyllophagous generations. The use of already adapted fungal species to control one of the major pests of olive groves will increase the success of a future biocontrol strategy. In this context, the identification of fungi associated to P. oleae from olive orchards provided a pool of potential biocontrol agents. In this work, Beauveria bassiana proved to be the most promising fungus to be used as biocontrol agent against olive moth, being strongly associated to the phyllophagous generation. Other fungal species presenting entomopathogenic, antagonistic and phytopathogenic characteristics were also found.This work has been supported by FCT (PTDC/AGR-AAM/102600/2008)

    Biotechnological applications of selected macroalgae

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    IBBA Strategic Planning - Workshop III, Plant Biotechnology Ponta Delgada, 25 Janeiro, 2011

    Antioxidant activity of macroalgae from the Azores

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    Free radical scavenging activity (FRSA) was studied to determine the antioxidant activity of 8 common macroalgae species found in the Azores. Species under study were Porphyra sp., Osmundea pinnatifida, Pterocladiella capillacea, Sphaerococcus coronopifolius and Gelidium microdon, from Rhodophyta; Ulva compressa and Chaetomorpha pachynema, from Chlorophyta and Fucus spiralis from Phaeophyta.The antioxidant activity was evaluated in methanolic extract by a decolourisation solution test of 2,2-diphenyl-1-picrylhydrazyl (DPPH), used as a stable radical. The methanolic extracts were obtained from dried biomass by sequential extractions, attaining a final concentration of 2 mg.mL-1. The FRSA values ranged from 19.54% for S. coronopifolius to 60.05% for F. spiralis with standard deviation (SD) varying between 1.41% and 6.80%. Results indicated that the studied seaweeds are a very promising source of biological active compounds with antioxidante properties. The seaweeds were collected in the Azorean islands where seawater pollution levels are low. Consequently, these seaweeds represent a valuable and good source of antioxidante material with superior beneficial effects on human health

    Mais-valia nutricional de macroalgas marinhas dos Açores. Determinação do teor de fibra bruta.

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    IV Congresso da Ordem dos Biólogos e II Congresso dos Biólogos dos Açores (Painel Biologia Marinha e Oceanografia). Ponta Delgada, Açores, 13-15 de Outubro de 2011

    DEVELOPMENT OF A SCADA SYSTEM FOR ACCESS, PROCESSING AND SUPERVISION OF DATA COMING FROM A WIRELESS SENSORS NETWORK IN AGRO-ENVIRONMENTAL APPLICATIONS

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    Wireless sensors networks appeared in the 1970’s for military and industrial use. They have since undergone a major evolution, particularly since the 90’s, thanks to the improvements in wireless communications. These changes have allowed them to participate in a wide variety of applications in different sectors such as agriculture and environment. This paper shows the development of a SCADA application programmed with LabVIEW® 8.6 (National Instruments), which allows management of data received by wireless sensors networks through a friendly interface for users. For the application shown in this paper we have worked with a MEP 510 sensors network (Crossbow). The functionalities implemented are the following: Network configuration; Data storage into database; Statistical processing of historical data with polynomial adjustment and spline interpolation; Visualization by data graphics in real time and historical data; Visualization of 2D intensity diagrams from the spatial distribution of sensors; and Creation of a users registry system that allows, depending on the category assigned, receiving or not access privileges in the application. As a complement we have developed the possibility of remote access. Sensors network implemented and the applications developed have been checked by operational tests for each functionality, as well as sensors joining and leaving the network situations, range of variables and working modes. The results obtained show the robustness of the SCADA application and the limitations of wireless sensors networks operating on field conditions
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