Comparação do ágar suco de tomate com outros três meios, na diferenciação entre C. albicans e C. dubliniensis

O presente estudo teve como objetivo comparar o ágar suco de tomate, um tradicional meio utilizado para observação de ascósporos em leveduras, com o ágar semente de niger, ágar caseína e ágar semente de girassol, na diferenciação fenotípica entre C. albicans e C. dubliniensis. Após 48 h de incubação a 30 ºC, os 26 isolados de C. dublinienis (100%) evidenciaram a formação de clamidoconídios igualmente em todos os meios comparados. Entretanto, quando semeados com C. albicans, a formação de clamidoconídios foi raramente observada, resultando nos seguintes percentuais de ausência destas estruturas: ágar suco de tomate (92,47%), ágar niger (96,7%), ágar caseína (91,39%), ágar semente de girassol (96,7%). Estes resultados permitem-nos sugerir a utilização do ágar suco de tomate como mais um meio que, já no primo-isolamento, é capaz de, presuntivamente, diferenciar C. albicans de C. dubliniensis.The purpose of the present study is to compare the tomato juice agar, a well known medium employed to observe ascospore formation, with niger seed agar, casein agar and sunflower seed agar, applied to a differentiation between C. dubliniensis and C. albicans. After 48 hours of incubation at 30 ºC all 26 (100%) C. dubliniensis isolates tested produced chlamydospores on tomato juice agar as well as in the other three media evaluated. However, when we inoculated all media with C. albicans, the absence of chlamydospores became resulting in the following percents: tomato juice agar (92.47%), niger seed agar (96.7%), casein agar (91.39%), and sunflower seed agar (96.7%). These results indicate that tomato juice agar is another medium which can also be used in the first phenotypic differentiation between C. dubliniensis and C. albicans

Egg parasitoid wasps as natural enemies of the neotropical stink bug Dichelops melacanthus

O objetivo deste trabalho foi determinar o potencial de cinco espécies de vespas Scelionidae – Telenomus podisi, Trissolcus basalis, Trissolcus urichi, Trissolcus teretis e Trissolcus brochymenae –, como inimigos naturais do percevejo neotropical Dichelops melacanthus, e determinar se a presença de ovos de outras espécies de percevejo tem influência sobre o parasitismo e o desenvolvimento dos parasitoides. Foram realizados dois tipos de experimentos em laboratório: sem escolha de hospedeiros (ovos de D. melacanthus) e com escolha (ovos de D. melacanthus e de Euschistus heros). Foram registrados parâmetros biológicos que incluíram: proporção de parasitismo, sobrevivência de imaturos, razão sexual da progênie, tempo de desenvolvimento dos estágios imaturos e preferência de hospedeiro. Todas as espécies de parasitóides avaliadas podem parasitar e desenvolver-se em ovos de D. melacanthus. A escolha inicial de ovos não influenciou a proporção de ovos de D. melacanthus parasitados por Tr. basalis, Tr. teretis ou Tr. brochymenae. Entretanto, para Te. podisi e Tr. urichi, a escolha inicial por ovos de D. melacanthus aumentou em 9 e 14 vezes, respectivamente, a chance de parasitismo nesta espécie. Aspectos comportamentais e ecológicos dos inimigos naturais devem ser considerados antes de sua utilização em programas de controle biológico.The objective of this work was to determine the potential of five species of Scelionidae wasps – Telenomus podisi, Trissolcus basalis, Trissolcus urichi, Trissolcus teretis and Trissolcus brochymenae – as natural enemies of the neotropical stink bug Dichelops melacanthus, and to determine if the presence of eggs of other stink bug species influences the parasitism and development of the parasitoids. Two kinds of experiments were done in laboratory: without choice of hosts (eggs of D. melacanthus) and with choice (eggs of D. melacanthus and of Euschistus heros). Biological parameters, including proportion of parasitism, immature survivorship, progeny sex ratio, immature stage development period, and host preference were recorded. All the evaluated parasitoids can parasitize and develop on D. melacanthus eggs. The first choice of eggs did not influence the proportion of D. melacanthus eggs parasitized by Tr. basalis, Tr. teretis or Tr. brochymenae. However, D. melacanthus eggs as the first choice of Te. podisi and Tr. urichi increased, respectively, 9 and 14 times the chance for parasitism on eggs of this species. Behavioral and ecological aspects of parasitoids should be considered prior to their use in biological control programs

A Model of DENV-3 Infection That Recapitulates Severe Disease and Highlights the Importance of IFN-γ in Host Resistance to Infection

There are few animal models of dengue infection, especially in immunocompetent mice. Here, we describe alterations found in adult immunocompetent mice inoculated with an adapted Dengue virus (DENV-3) strain. Infection of mice with the adapted DENV-3 caused inoculum-dependent lethality that was preceded by several hematological and biochemical changes and increased virus dissemination, features consistent with severe disease manifestation in humans. IFN-γ expression increased after DENV-3 infection of WT mice and this was preceded by increase in expression of IL-12 and IL-18. In DENV-3-inoculated IFN-γ−/− mice, there was enhanced lethality, which was preceded by severe disease manifestation and virus replication. Lack of IFN-γ production was associated with diminished NO-synthase 2 (NOS2) expression and higher susceptibility of NOS2−/− mice to DENV-3 infection. Therefore, mechanisms of protection to DENV-3 infection rely on IFN-γ-NOS2-NO-dependent control of viral replication and of disease severity, a pathway showed to be relevant for resistance to DENV infection in other experimental and clinical settings. Thus, the model of DENV-3 infection in immunocompetent mice described here represents a significant advance in animal models of severe dengue disease and may provide an important tool to the elucidation of immunopathogenesis of disease and of protective mechanisms associated with infection

Preferences for menu labelling formats of young adults in Brazil and in the United Kingdom

Objective This pilot study was aimed at exploring preferences of young adults in two different contexts on restaurant menu labelling formats. Methods Five focus groups were conducted with 36 participants, two focus groups with 11 participants in Brazil and three focus groups with 25 in the United Kingdom. Themes originating from the content analysis of the transcriptions were organised around four possible menu labelling formats: 1) numerical information on calories; 2) numerical information on calories and nutrients; 3) traffic light system plus Guideline Daily Amounts; 4) food information with ingredients list plus highlighted symbols. Results In both countries, participants preferred the ingredients list plus symbols format, considered more comprehensive and useful to make an informed food choice. Organic food and vegetarian symbols were the ones considered most important to appear on restaurant menu labels with ingredients list. However, most participants in Brazil and in the United Kingdom rejected the information restricted to calories and calories plus nutrients formats, saying that these would not influence their own choices. Conclusion This is the first multicultural qualitative study exploring preferences of people living in different countries with different eating habits, but where menu labelling is voluntary. Results evidenced similarities in participants' likes and dislikes for menu labelling formats in these two different contexts. Discussions showed participants in both countries prefer qualitative information than numerical information, suggesting that ingredients list and symbols provide information that people want to see on the menu

Reference genes for quantitative reverse transcription-polymerase chain reaction expression studies in wild and cultivated peanut

<p>Abstract</p> <p>Background</p> <p>Wild peanut species (<it>Arachis </it>spp.) are a rich source of new alleles for peanut improvement. Plant transcriptome analysis under specific experimental conditions helps the understanding of cellular processes related, for instance, to development, stress response, and crop yield. The validation of these studies has been generally accomplished by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) which requires normalization of mRNA levels among samples. This can be achieved by comparing the expression ratio between a gene of interest and a reference gene which is constitutively expressed. Nowadays there is a lack of appropriate reference genes for both wild and cultivated <it>Arachis</it>. The identification of such genes would allow a consistent analysis of qRT-PCR data and speed up candidate gene validation in peanut.</p> <p>Results</p> <p>A set of ten reference genes were analyzed in four <it>Arachis </it>species (<it>A. magna</it>; <it>A. duranensis</it>; <it>A. stenosperma </it>and <it>A. hypogaea</it>) subjected to biotic (root-knot nematode and leaf spot fungus) and abiotic (drought) stresses, in two distinct plant organs (roots and leaves). By the use of three programs (GeNorm, NormFinder and BestKeeper) and taking into account the entire dataset, five of these ten genes, <it>ACT1 </it>(actin depolymerizing factor-like protein), <it>UBI1 </it>(polyubiquitin), <it>GAPDH </it>(glyceraldehyde-3-phosphate dehydrogenase), <it>60S </it>(60S ribosomal protein L10) and <it>UBI2 </it>(ubiquitin/ribosomal protein S27a) emerged as top reference genes, with their stability varying in eight subsets. The former three genes were the most stable across all species, organs and treatments studied.</p> <p>Conclusions</p> <p>This first in-depth study of reference genes validation in wild <it>Arachis </it>species will allow the use of specific combinations of secure and stable reference genes in qRT-PCR assays. The use of these appropriate references characterized here should improve the accuracy and reliability of gene expression analysis in both wild and cultivated Arachis and contribute for the better understanding of gene expression in, for instance, stress tolerance/resistance mechanisms in plants.</p

Reference Genes for Accurate Transcript Normalization in Citrus Genotypes under Different Experimental Conditions

Real-time reverse transcription PCR (RT-qPCR) has emerged as an accurate and widely used technique for expression profiling of selected genes. However, obtaining reliable measurements depends on the selection of appropriate reference genes for gene expression normalization. The aim of this work was to assess the expression stability of 15 candidate genes to determine which set of reference genes is best suited for transcript normalization in citrus in different tissues and organs and leaves challenged with five pathogens (Alternaria alternata, Phytophthora parasitica, Xylella fastidiosa and Candidatus Liberibacter asiaticus). We tested traditional genes used for transcript normalization in citrus and orthologs of Arabidopsis thaliana genes described as superior reference genes based on transcriptome data. geNorm and NormFinder algorithms were used to find the best reference genes to normalize all samples and conditions tested. Additionally, each biotic stress was individually analyzed by geNorm. In general, FBOX (encoding a member of the F-box family) and GAPC2 (GAPDH) was the most stable candidate gene set assessed under the different conditions and subsets tested, while CYP (cyclophilin), TUB (tubulin) and CtP (cathepsin) were the least stably expressed genes found. Validation of the best suitable reference genes for normalizing the expression level of the WRKY70 transcription factor in leaves infected with Candidatus Liberibacter asiaticus showed that arbitrary use of reference genes without previous testing could lead to misinterpretation of data. Our results revealed FBOX, SAND (a SAND family protein), GAPC2 and UPL7 (ubiquitin protein ligase 7) to be superior reference genes, and we recommend their use in studies of gene expression in citrus species and relatives. This work constitutes the first systematic analysis for the selection of superior reference genes for transcript normalization in different citrus organs and under biotic stress