5,341 research outputs found

    Characterization of the dry bean polygalacturonase-inhibiting protein (PGIP) gene family during Sclerotinia sclerotiorum (Sclerotiniaceae) infection.

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    Polygalacturonase-inhibiting proteins are leucine-rich repeat proteins that inhibit fungal endopolygalacturonases. The interaction of polygalacturonase-inhibiting protein with endopolygalacturonases limits the destructive potential of endopolygalacturonases and may trigger plant defense responses induced by oligogalacturonides. We examined the expression of fungal pg and plant Pvpgip genes in bean (Phaseolus vulgaris) stems infected with Sclerotinia sclerotiorum to determine whether any of them are associated with the infection process. Transcriptional analysis was carried out by means of semi-quantitative reverse transcription PCR or real-time PCR. The sspg1 gene was highly expressed during infection; sspg3 was regulated during the later phases of infection; sspg5 was more uniformly expressed during infection, whereas sspg6 was only weakly expressed. During the course of infection, Pvpgip1 transcripts were not detected at early stages, but they appeared 72 h post-inoculation. High levels of Pvpgip2 expression were observed during the initial phase of infection; the transcript peaked by 48 h post-inoculation and declined by 72 h post-inoculation. Pvpgip3 expression increased strongly at 96 h post-inoculation. Pvpgip4 was constantly present from 24 h post-inoculation until the end of the experiment. However, we detected higher levels of the Pvpgip4 transcript in the necrotic lesion area than in plants that had been mechanically wounded. Remarkably, only Pvpgip4 appeared to be moderately induced by mechanical wounding. These results provide evidence that endopolygalacturonases contribute to the infection process during host colonization by promoting the release of plant cell oligogalacturonides, which are powerful signaling molecules and may also activate plant defenses, such as polygalacturonase-inhibiting proteins

    Dynamical analysis of the cluster pair: A3407 + A3408

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    We carried out a dynamical study of the galaxy cluster pair A3407 \& A3408 based on a spectroscopic survey obtained with the 4 meter Blanco telescope at the CTIO, plus 6dF data, and ROSAT All-Sky-Survey. The sample consists of 122 member galaxies brighter than mR=20m_R=20. Our main goal is to probe the galaxy dynamics in this field and verify if the sample constitutes a single galaxy system or corresponds to an ongoing merging process. Statistical tests were applied to clusters members showing that both the composite system A3407 + A3408 as well as each individual cluster have Gaussian velocity distribution. A velocity gradient of 847±114\sim 847\pm 114 km  s1\rm km\;s^{-1} was identified around the principal axis of the projected distribution of galaxies, indicating that the global field may be rotating. Applying the KMM algorithm to the distribution of galaxies we found that the solution with two clusters is better than the single unit solution at the 99\% c.l. This is consistent with the X-ray distribution around this field, which shows no common X-ray halo involving A3407 and A3408. We also estimated virial masses and applied a two-body model to probe the dynamics of the pair. The more likely scenario is that in which the pair is gravitationally bound and probably experiences a collapse phase, with the cluster cores crossing in less than \sim1 h1h^{-1} Gyr, a pre-merger scenario. The complex X-ray morphology, the gas temperature, and some signs of galaxy evolution in A3408 suggests a post-merger scenario, with cores having crossed each other 1.65h1\sim 1.65 h^{-1}Gyr ago, as an alternative solution.Comment: 17 pages, 12 figures, submitted to MNRAS, accepted 2016 May 9. Received 2016 May 9; in original form 2016 April 1

    Quantificação da atividade microbiana e qualidade nutricional do solo em plantio adensado de Nim Indiano (Azadirachta indica A. Juss.) no Território de Identidade Bacia do Paramirim - Semi-árido baiano.

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    A introdução do Nim indiano na silvicultura brasileira vem sendo popularizada através de práticas de manejo empíricas. Estudos relacionados à produtividade e impactos ambientais motivados pelo adensamento indiscriminado da cultura ainda são insipientes. Um ponto crítico é a capacidade antimicrobiana e inseticida da Azadiractina, principio ativo extraído da parte aérea como inseticida botânico, no controle de pragas e doenças na agricultura.Em paralelo aconteceram também os seguintes eventos: V Seminário de Pesquisa do Recôncavo da Bahia; V Seminário Estudantil de Pesquisa da UFRB; V Seminário da Pós-Graduação da UFRB; II Seminário Regional de Pesquisa da EBDA; 5ª Jornada Científica da Embrapa Mandioca e Fruticultura; VIII Seminário Estudantil de Pesquisa e Extensão da FAMAM; Semana de Ciência, Tecnologia e Inovação no Agronegócio; Fórum de Gestores de Iniciação Científica e Tecnológica da Bahia; II Simpósio Baiano de Defesa Agropecuária; I Semana de Educação Tutorial da UFRB

    The solar, exoplanet and cosmological lithium problems

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    We review three Li problems. First, the Li problem in the Sun, for which some previous studies have argued that it may be Li-poor compared to other Suns. Second, we discuss the Li problem in planet hosting stars, which are claimed to be Li-poor when compared to field stars. Third, we discuss the cosmological Li problem, i.e. the discrepancy between the Li abundance in metal-poor stars (Spite plateau stars) and the predictions from standard Big Bang Nucleosynthesis. In all three cases we find that the "problems" are naturally explained by non-standard mixing in stars.Comment: Astrophysics and Space Science, in press. New version has one reference correcte
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