27 research outputs found

    Cytological aspects of compatible and incompatible interactions between cashew (Anacardium occidentale L.) seedlings and isolates of Colletotrichum gloeosporioides (Penz.) complex

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    A strategy in the control anthracnose of cashew (Anacardium occidentale L.) is the management of crop phenology and defense mechanisms of this host. In previous studies, under controlled conditions, the seedling reactions of 5 cashew clones (CAP-14, CCP-06, CCP-09, CCP76 and CCP-1001) to 36 isolates of Colletorichum gloeosporioides Penz. complex (LARS- 905 to 940) was evaluated. However, good field management requires information about the infection process. This research aimed to clarify cytophysiological aspects of three compatible interactions of this pathosystem (isolates LARS-905 and 910 × CCP-76; LARS-910 × CCP-1001) and an incompatible one (LARS-905 × CCP-1001), using infected leaves/stems and microscopy (light, scanning and transmission electron). No significant differences were found prior to penetration. In the susceptible combinations, 36-66 h after inoculation, a thin primary hypha (TPH) formed in the invaded epidermal cell, widening as a large primary hypha (LPH), which filled the cell lumen simultaneously with accumulation of of yellow-brown lignopolysaccharides. Then, a thin secondary hypha (TSH) developed from the LPH, penetrating adjacent cells before the first became necrotic. In the incompatible interaction, the response of the first invaded cell was faster and more intense, with formation of papilla and lignopolysaccharide-protein-silicon complex usually blocking the pathogen

    Influence of elevation and slope exposure on must volatiles of mencía cultivar from Ribeira Sacra (NW Spain)

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    Ribeira Sacra is a Spanish Denomination of Origen (D.O.) that produces young red wines from Mencía cultivar (Galicia, NW). The orography of the Ribeira Sacra D.O. is very characteristic and renders a wide variety of situations that combine elevation, orientation, slope exposure and slope inclination. Indeed, in this area all have terraced vineyards are very close to just one meter wide, where it is only a single row of vines and spread over the slopes which normally have a large inclination (70 to 80 ° slope). With a south-southwest direction, the vineyards are protected from cold winds from the north and the sun bathes the terraces throughout the day. The stone warmed by the sun during the day blunted the lower night temperatures avoiding frost. During the year 2009 we have studied the volatile composition of Mencía cultivar in six different situations (orientation and altitude) of Amandi subzone (Ribeira Sacra D.O.) and the relationship with the altitude and exposition. The results showed the influence climatic and topographic conditions on the volatile composition of Mencía grape grown along Amandi site from Ribeira Sacra D.O. Six different situations were studied and the data were analysed by analysis of variance and mean differences between situations were calculated using the LSD Fishers’ test. Biplot principal component analysis (PCA) was performed with mean of volatile compounds identified and quantified. The results showed significant differences among the different situations studied, showed different ripening states in the vineyard

    The Electroweak Chiral Lagrangian and CP-Violating Effects in Technicolor Theories

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    We estimate the CP-violating WWγWW\gamma and WWZWWZ anomalous form factors, arising from CP-violating interactions in extended technicolor theories, and discuss their future experimental detectability. The electric dipole moment of the WW boson is found to be as large as {\cal O}(10^{-21}) \; \mbox{e cm}. We connect the CP-odd WWγWW\gamma and WWZWWZ couplings to the corresponding CP-violating electroweak chiral lagrangian operators. The electric dipole moments of the neutron and the electron in technicolor theories are estimated to be as large as {\cal O}(10^{-26}) \; \mbox{e cm} and {\cal O}(10^{-29}) \; \mbox{e cm} respectively. We also suggest the potential to observe large CP-violating technicolor effects in the decay t→b+W+t \rightarrow b + W^+.Comment: 34 pages, YCTP-P9-94, LaTex. (minor changes in wording and notation, the figures are appended at the end as one postscript file

    Highly Divergent Mitochondrial ATP Synthase Complexes in Tetrahymena thermophila

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    Tetrahymena ATP synthase, an evolutionarily divergent protein complex, has a very unusual structure and protein composition including a unique Fo subunit a and at least 13 proteins with no orthologs outside of the ciliate lineage

    Colletotrichum isolates related to anthracnose of cashew trees in Brazil: morphological and molecular description using LSU rDNA sequences

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    Thirty six isolates of fungi obtained from anthracnose lesions of cashew and associated host plants in Brazil, were compared by their cultural, morphological and partial sequences of the 28S ribosomal DNA characters. They showed a high degree of cultural variability. The average mycelial growth rate on all tested media ranged from 10.2-13.3 mm/day between the isolates. Most of them produced perithecia (sterile and fertile) and some produced setae (sterile and fertile). All the isolates produced acervuli with predominantly cylindrical conidia (12.4-17.7 µmX 4.8-6.0 µm in width) with round ends, which became septate on germination, and produced unlobed or slightlylobed appressoria. Comparison of the D2 domain of the large subunit (LSU) rDNA sequences with those of other defined species of Colletotrichum and Glomerella grouped 35 of the isolates with known strains of C. gloeosporioides from different hosts (> 98.9% homology). The one exception (LARS 921) was identical to G. cingulata (LARS 238) from Vigna unguiculata.Trinta e seis isolados de fungos obtidos de lesões de antracnose em cajueiros e outras plantas consorciadas no Brasil, foram comparados quanto a seus aspectos culturais, morfológicos e seqüências parciais do rDNA 28S. Os isolados apresentaram elevado grau de variabilidade cultural, com taxa de crescimento médio, em todos os meios testados, entre 10,2 e 13,3 mm/dia. A maioria deles produziu peritécios (estéreis e férteis), e alguns produziram setas (estéreis e férteis) nos diferentes meios. Todos apresentaram acérvulos com predominância de conídios cilíndricos (12,4-17,7 µm X 4,8-6,0 µm), de extremidades arredondadas, formando septos durante a germinação e produzindo apressórios ligeiramente lobados ou lisos. Comparando as seqüências do domínio D2 da larga subunidade (LSU) do rDNA dos isolados com aquelas já identificadas de espécies de Colletotrichum/ Glomerella, verificou-se que 35 deles correspondem a C. gloeosporioides (> 98,9% de homologia), e um deles, o isolado 921, é idêntico a G. cingulata (LARS 238) de V. unguiculata

    Reaction of dwarf cashew clones to Colletotrichum gloeosporioides isolates in controlled environment

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    The cashew (Anacardium occidentale L.) crop is an important source of income for the population of the Brazilian Northeast, and anthracnose disease caused by Colletotrichum gloeosporioides leads to significant production loss. However, there is little information on either the host resistance or the variation in the aggressiveness of the pathogen under controlled environment. The reaction of commercial (CCP-06, CCP-09, CCP-76 and CCP-1001) and one non-commercial (CAP-14) dwarf cashew clones was assessed against 36 isolates of this fungus controlled environmental conditions. All the isolates, including those from hosts other than cashew, were able to cause lesions on leaves and stems of most clones, albeit to different degrees. Clone CCP-06 was the most susceptible, while clone CCP-1001 showed a level of resistance to a number of the isolates, including isolate 905, while isolates 910 and 912 were aggressive to all clones. Injury increased the susceptibility of the clones to all isolates, indicating that resistance also might be associated with structural barriers that hinder penetration. Ripened cashew apples (8-week-old), of commercial clones were susceptible to isolates 905 and 910. Immature pseudo-fruits (2-week-old), with exception of clone CCP-76 which was susceptible to both isolates showed resistance against these isolates, suggesting the presence of structural and chemical barriers. Developed nuts (8-week-old), however, were more resistant than immature nuts (2-week-old) to both isolates, probably due to their thicker exocarp cuticle and reduced number of stomatal pores.A cultura de caju (Anacardium occidentale L.) é uma fonte de renda importante para a população do Nordeste brasileiro, sendo a antracnose causada por Colletotrichum gloeosporioides a doença que mais conduz a perdas de sua produção. Entretanto, há pouca informação para a resistência desse hospedeiro ou para a variação na agressividade do patógeno em ambiente controlado. A reação de clones comerciais (CCP-06, CCP-09, CCP-76 e CCP-1001) e um não comercial (CAP-14) de cajueiros anão-precoce, contra 36 isolados desse fungo, foi avaliada sob condições controladas. Todos os isolados, incluindo os provenientes de diferentes hospedeiros, foram capazes de causar lesões sobre folhas e hastes da maioria dos clones, ainda que em graus diferenciados. O clone CCP-06 foi o mais suscetível, enquanto o clone CCP-1001 foi resistente a mais isolados, incluindo o 905, enquanto os isolados 910 e 912 foram agressivos a todos os clones testados. A injúria mecânica das folhas aumentou a suscetibilidade dos clones a todos os isolados, indicando que a resistência pode também estar associada a barreiras estruturais que impedem a penetração. Os pseudofrutos amadurecidos (8 semanas) dos clones comerciais avaliados, foram suscetíveis a ambos os isolados testados (905 e 910), mas os jovens (2 semanas), com exceção daqueles do clone CCP-76, suscetíveis aos dois isolados, apresentaram resistência a ambos, sugerindo a ação de obstáculos estruturais e químicos diferenciados. As castanhas desenvolvidas (8 semanas), no entanto, foram mais resistentes a ambos os isolados do que as jovens (2 semanas), talvez devido à espessa cutícula do exocarpo e baixo número de estômatos

    Alternative approach to solve the 1-D quantum harmonic oscillator

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    In standard courses of Quantum Mechanics the harmonic oscillator is frequently resolved through of different techniques. In this paper, we introduce another didactic method to obtain its energy spectrum and wave functions by using directly the Hermite polynomials. To do this we only use arguments of general soundness.En cursos normales de Mecánica Cuántica, el oscilador armónico es frecuentemente resuelto a través de diferentes técnicas. En este artículo, introducimos otro método didáctico para determinar su espectro de energía y sus funciones de onda, usando directamente polinomios de Hermite. Para hacer esto solamente consideramos argumentos de validez general
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