Associação de Colletotrichum e Fusarium com queima de ponteiras em erva-mate.

A erva-mate é uma espécie arbórea explorada comercialmente para a produção de chimarrão, chás e seus derivados, de importância econômica e social na região Sul do Brasil. As doenças de plantas são fatores que diminuem a sua produtividade e qualidade. Brotações e gemas têm sido observadas com sintomas de queima em fase de mudas (viveiro) e árvores jovens (campo nativo e plantios comerciais) em diferentes localidades. Os sintomas surgem após períodos de chuvas combinados com temperaturas extremas, inclusive com geada, principalmente nas brotações novas após a poda de colheita. Amostras de ponteiras doentes coletadas nos municípios de Colombo e União da Vitória, PR, foram analisadas em laboratório. Processou-se o isolamento direto (ponteiras doentes colocadas em câmara úmida constituída de caixas gerbox com papel de filtro umedecido com água ultrapurificada) e isolamento indireto (esterilização superficial de fragmentos da porção doente pela imersão por 30 segundos em solução álcool 70%, imersão em solução 1% de hipoclorito de sódio por 1 minuto e posterior plaqueamento em meio batata-dextrose-ágar + antibiótico). Caixas gerbox e placas com meio de cultura foram incubadas a 24 °C até o surgimento de colônias e estruturas reprodutivas. Exames ao microscópio revelaram a presença de acérvulos e conídios de Colletotrichum spp. e de esporodóquios e conídios de Fusarium spp. Estudos complementares de identificação taxonômica serão feitos por meio de métodos moleculares. Postula-se que a associação destes fungos com a queima das ponteiras de erva-mate seja decorrente de condições climáticas de alta umidade e temperaturas ótimas.Resumo

Neutrino Unification

Present neutrino data are consistent with neutrino masses arising from a common seed at some ``neutrino unification'' scale $M_X$. Such a simple theoretical ansatz naturally leads to quasi-degenerate neutrinos that could lie in the electron-volt range with neutrino mass splittings induced by renormalization effects associated with supersymmetric thresholds. In such a scheme the leptonic analogue of the Cabibbo angle $\theta_{\odot}$ describing solar neutrino oscillations is nearly maximal. Its exact value is correlated with the smallness of $\theta_{reactor}$. These features agree both with latest data on the solar neutrino spectra and with the reactor neutrino data. The two leading mass-eigenstate neutrinos present in \ne form a pseudo-Dirac neutrino, avoiding conflict with neutrinoless double beta decay.Comment: RevTex format, 2 figures, 4 pages, a few new references, no other important change, figures unchanged, version to be published in PR

Neutrino mass spectrum and neutrinoless double beta decay

The relations between the effective Majorana mass of the electron neutrino, $m_{ee}$, responsible for neutrinoless double beta decay, and the neutrino oscillation parameters are considered. We show that for any specific oscillation pattern $m_{ee}$ can take any value (from zero to the existing upper bound) for normal mass hierarchy and it can have a minimum for inverse hierarchy. This means that oscillation experiments cannot fix in general $m_{ee}$. Mass ranges for $m_{ee}$ can be predicted in terms of oscillation parameters with additional assumptions about the level of degeneracy and the type of hierarchy of the neutrino mass spectrum. These predictions for $m_{ee}$ are systematically studied in the specific schemes of neutrino mass and flavor which explain the solar and atmospheric neutrino data. The contributions from individual mass eigenstates in terms of oscillation parameters have been quantified. We study the dependence of $m_{ee}$ on the non-oscillation parameters: the overall scale of the neutrino mass and the relative mass phases. We analyze how forthcoming oscillation experiments will improve the predictions for $m_{ee}$. On the basis of these studies we evaluate the discovery potential of future \znbb decay searches. The role \znbb decay searches will play in the reconstruction of the neutrino mass spectrum is clarified. The key scales of $m_{ee}$, which will lead to the discrimination among various schemes are: $m_{ee} \sim 0.1$ eV and $m_{ee} \sim 0.005$ eV.Comment: 47 pages, 35 figure

CD8+ DC, but Not CD8−DC, Isolated from BCG-Infected Mice Reduces Pathological Reactions Induced by Mycobacterial Challenge Infection

Tuberculosis is a mycobacterial infection causing worldwide public health problems but the available vaccine is far from ideal. Type-1 T cell immunity has been shown to be critical for host defence against tuberculosis infection, but the role of dendritic cell (DC) subsets in pathogenesis of mycobacterial infection remains unclear.We examined the effectiveness of dendritic cell (DC) subsets in BCG-infected mice in generating immune responses beneficial for pathogen clearance and reduction of pathological reactions in the tissues following challenge infection. Our data showed that only the adoptive transfer of the subset of CD8alpha+ DC isolated from infected mice (iCD8+ DC) generated significant protection, demonstrated by less mycobacterial growth and pathological changes in the lung and liver tissues in iCD8+ DC recipients than sham-treated control mice. The adoptive transfer of the CD8alpha(-)DC from the infected mice (iCD8(-) DC) not only failed to reduce bacterial growth, but enhanced inflammation characterized by diffuse heavy cellular infiltration. Notably, iCD8(-) DC produced significantly higher levels of IL-10 than iCD8+ DC and promoted more Th2 cytokine responses in in vitro DC-T cell co-culture and in vivo adoptive transfer experiments.The data indicate that in vivo BCG-primed CD8+ DC is the dominant DC subset in inducing protective immunity especially for reducing pathological reactions in infected tissues. The finding has implications for the rational improvement of the prophylactic and therapeutic approaches for controlling tuberculosis infection and related diseases

Interruption of CXCL13-CXCR5 Axis Increases Upper Genital Tract Pathology and Activation of NKT Cells following Chlamydial Genital Infection

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