Propriétés insecticides de Chenopodium ambrosoides et Tephrosia vogelii vers la bruche de l'arachide Caryedon serratus

L'efficacité de poudres de #Tephrosia vogelii (une source connue de roténone) et de cinq autres plantes utilisées traditionnellement au Congo pour la protection des stocks contre les insectes, a été évaluée. A la dose de 1 pour 40, #Chenopodium ambrosioides et #Tephrosia vogelii affectent la survie des adultes de #Caryedon serratus : 90,0 et 98,8 %, respectivement, meurent au bout de 13 jours. Le nombre d'oeufs pondus est très faible ou nul. Les autres plantes n'ont aucun effet ou un effet mineur sur les différents stades de l'insecte. (Résumé d'auteur

Механизмы образования мишенных инсерций при синтезе молекулы ДНК, содержащей цис-син циклобутановые цитозиновые димеры

В рамках развиваемой полимеразно-таутомерной модели ультрафиолетового мутагенеза предлагается модель механизма образования мишенных инсерций, вызванных цис-син циклобутановыми цитозиновыми димерами. Инсерции — это мутации сдвига рамки чтения, когда встраивается одно или несколько оснований ДНК. Структурный анализ встраивания оснований показал, что напротив двух редких таутомерных форм цитозина невозможно встроить ни одно из канонических оснований так, чтобы между ними и матричными основаниями образовались водородные связи. Поэтому при синтезе молекулы ДНК, содержащей цис-син циклобутановые цитозиновые димеры, содержащие молекулы цитозина в таких редких таутомерных формах, специализированные или модифицированные ДНК-полимеразы напротив этих цис-син циклобутановых цитозиновых димеров будут оставлять бреши в один нуклеотид. На участках ДНК с однородным нуклеотидным составом, в соответствии с моделью Стрейзингера, конец нити ДНК может сползти, соединиться с помощью водородных связей так, что образуется петля. В результате дочерняя нить удлиняется, появляется мишенная мутация сдвига рамки чтения — мишенная инсерция.У рамках розроблюваної полiмеразно-таутомерної моделi ультрафiолетового мутагенезу, запропоновано модель механiзму формування мiшенних iнсерцiй, що викликанi цис-син циклобутановими цитозиновими димерами. Iнсерцiї — це мутацiї зсуву рамки читання, коли вбудовується одна або декiлька основ ДНК. Структурний аналiз вбудовування основ показав, що навпроти двох рiдких таутомерних станiв цитозину неможливо вбудувати жодну з канонiчних основ так, щоб мiж ними та матричними основами сформувались водневi зв’язки. Тому при синтезi молекули ДНК, що мiстить цис-син циклобутановi цитозиновi димери, що мають молекули цитозину в таких рiдких таутомерних формах, спецiалiзованi або модифiкованi ДНК-полiмерази навпроти цих цис-син циклобутанових цитозинових димерiв будуть залишати проломи в один нуклеотид. На дiлянках ДНК з однорiдним нуклеотидним складом, вiдповiдно до моделi Стрейзингера, кiнець нитки ДНК може сповзти, з’єднатися за допомогою водневих зв’язкiв так, що утвориться петля. У результатi подовжується дочiрня нитка, з’являється мiшенна мутацiя зсуву рамки читання — мiшенна iнсерцiя.A polymerase — tautomer model of ultraviolet mutagenesis is developed. The mechanism of formation of targeted insertions that is caused by cis-syn cyclobutane cytosine dimers is proposed. Insertions are frameshift mutations, when one or several DNA bases are inserted. Structural analysis has shown that, opposite two rare tautomeric forms of cytosine, it is impossible to insert any canonical DNA bases with template bases with the formation of hydrogen bonds. Therefore, under the synthesis of DNA containing cis-syn cyclobutane cytosine dimers with cytosine molecules in such rare tautomeric forms, specialized or modified DNA polymerases will leave one nucleotide gaps opposite these cis-syn cyclobutane cytosine dimers. On DNA sites with homogeneous nucleotide composition, the end of a DNA strand may slip and join with hydrogen bonds so that a loop is formed by the Streisinger model. As a result, the daughter strand is elongated, and the targeted insertion is formed

Les problèmes de conservation du manioc en cossettes au Congo

Une liste est fournie des insectes infestant les cossettes de manioc séchées au Congo. Au total, 12 espèces de coléoptères nuisibles ont été identifiées ; la plus nuisible est #Araecerus fasciculatus$. (Résumé d'auteur

Hematological variations in healthy participants exposed 2 h to propylene glycol ethers under controlled conditions.

Glycol ethers are solvents used in a plethora of occupational and household products exposing the users to potential toxic effects. Several glycol ethers derived from ethylene glycol induce hematological toxicity, such as anemia in workers. The exposure effects on blood cells of glycol ethers derived from propylene glycol are unknown in humans. The aim of our study was to evaluate blood parameters indicative of red blood cell (RBC) hemolysis and oxidative stress in participants exposed to propylene glycol (propylene glycol monobutyl ether (PGBE) and propylene glycol monomethyl ether (PGME)), two extensively used propylene glycol derivatives worldwide. Seventeen participants were exposed 2 h in a control inhalation exposure chamber to low PGME (35 ppm) and PGBE (15 ppm) air concentrations. Blood was regularly collected before, during (15, 30, 60, and 120 min), and 60 min after exposure for RBC and oxidative stress analyses. Urine was also collected for clinical effects related to hemolysis. Under the study conditions, our results showed that the blood parameters such as RBCs, hemoglobin concentration, and white blood cells tended to increase in response to PGME and PGBE exposures. These results raise questions about the possible effects in people regularly exposed to higher concentrations, such as workers

Comparative Testing Report on the Detection and Quantification of Maize Event MON 810 - Comparative testing round: ILC-CRL-GMFF-CT-02/10

In the frame of Regulation (EC) No 882/2004, the European Union Reference Laboratory for Genetically Modified Food and Feed has the duty to organise comparative testing rounds and to ensure an appropriate follow-up of these activities. This report describes the outcome of the second comparative testing round ILC-CRL-GMFF-CT-02/10. Participants had to determine the GM content in two test items denoted maize powder levels 1 and 2, containing different GM percentages of maize event MON 810. This comparative testing round was organised in collaboration with the Reference Materials Unit and the Food Safety and Quality Unit of the Institute for Reference Materials and Measurements (Geel, BE). The maize event MON 810 test items were produced by the Reference Materials Unit. The Food Safety and Quality Unit managed the on-line registration and submission of results. A total of 136 laboratories were invited to participate in ILC-CRL-GMFF-CT-02/10. Six National Reference Laboratories declined participation, of which two were no longer a National Reference Laboratory. Ninety laboratories from 41 countries returned results, of which 65 were National Reference Laboratories, six were members of the European Network of GMO Laboratories only and 19 were laboratories from third countries. Two National Reference Laboratories, two Official control laboratories and nine laboratories from a third country did not submit any results. Participants could report the results of the exercise either in mass/mass % or in copy/copy %. The outcome of this second comparative testing round was in general positive, with 82-100 % of participants gaining a z-score in the range of -2 to +2 for both maize powder levels 1 and 2 regardless of the calibration method, the measurement unit and the approach used for calculating the z-score.JRC.I.3-Molecular Biology and Genomic

The GOODSTEP project: General Object-Oriented Database for Software Engineering Processes

The goal of the GOODSTEP project is to enhance and improve the functionality of a fully object-oriented database management system to yield a platform suited for applications such as software development environments (SDEs). The baseline of the project is the O2 database management system (DBMS). The O2 DBMS already includes many of the features regulated by SDEs. The project has identified enhancements to O2 in order to make it a real software engineering DBMS. These enhancements are essentially upgrades of the existing O2 functionality, and hence require relatively easy extensions to the O2 system. They have been developed in the early stages of the project and are now exploited and validated by a number of software engineering tools built on top of the enhanced O2 DBMS. To ease tool construction, the GOODSTEP platform encompasses tool generation capabilities which allow for generation of integrated graphical and textual tools from high-level specifications. In addition, the GOODSTEP platform provides a software process toolset which enables modeling, analysis and enaction of software processes and is also built on top of the extended O2 database. The GOODSTEP platform is to be validated using two CASE studies carried out to develop an airline application and a business application

Pentamidine Dosage: A Base/Salt Confusion

Pentamidine has a long history in the treatment of human African trypanosomiasis (HAT) and leishmaniasis. Early guidelines on the dosage of pentamidine were based on the base-moiety of the two different formulations available. Confusion on the dosage of pentamidine arose from a different labelling of the two available products, either based on the salt or base moiety available in the preparation. We provide an overview of the various guidelines concerning HAT and leishmaniasis over the past decades and show the confusion in the calculation of the dosage of pentamidine in these guidelines and the subsequent published reports on clinical trials and reviews. At present, only pentamidine isethionate is available, but the advised dosage for HAT and leishmaniasis is (historically) based on the amount of pentamidine base. In the treatment of leishmaniasis this is probably resulting in a subtherapeutic treatment. There is thus a need for a new, more transparent and concise guideline concerning the dosage of pentamidine, at least in the treatment of HAT and leishmaniasi

Gene expression profiling of Spodoptera frugiperda hemocytes and fat body using cDNA microarray reveals polydnavirus-associated variations in lepidopteran host genes transcript levels

BACKGROUND: Genomic approaches provide unique opportunities to study interactions of insects with their pathogens. We developed a cDNA microarray to analyze the gene transcription profile of the lepidopteran pest Spodoptera frugiperda in response to injection of the polydnavirus HdIV associated with the ichneumonid wasp Hyposoter didymator. Polydnaviruses are associated with parasitic ichneumonoid wasps and are required for their development within the lepidopteran host, in which they act as potent immunosuppressive pathogens. In this study, we analyzed transcriptional variations in the two main effectors of the insect immune response, the hemocytes and the fat body, after injection of filter-purified HdIV. RESULTS: Results show that 24 hours post-injection, about 4% of the 1750 arrayed host genes display changes in their transcript levels with a large proportion (76%) showing a decrease. As a comparison, in S. frugiperda fat body, after injection of the pathogenic JcDNV densovirus, 8 genes display significant changes in their transcript level. They differ from the 7 affected by HdIV and, as opposed to HdIV injection, are all up-regulated. Interestingly, several of the genes that are modulated by HdIV injection have been shown to be involved in lepidopteran innate immunity. Levels of transcripts related to calreticulin, prophenoloxidase-activating enzyme, immulectin-2 and a novel lepidopteran scavenger receptor are decreased in hemocytes of HdIV-injected caterpillars. This was confirmed by quantitative RT-PCR analysis but not observed after injection of heat-inactivated HdIV. Conversely, an increased level of transcripts was found for a galactose-binding lectin and, surprisingly, for the prophenoloxidase subunits. The results obtained suggest that HdIV injection affects transcript levels of genes encoding different components of the host immune response (non-self recognition, humoral and cellular responses). CONCLUSION: This analysis of the host-polydnavirus interactions by a microarray approach indicates that the presence of HdIV induces, directly or indirectly, variations in transcript levels of specific host genes, changes that could be responsible in part for the alterations observed in the parasitized host physiology. Development of such global approaches will allow a better understanding of the strategies employed by parasites to manipulate their host physiology, and will permit the identification of potential targets of the immunosuppressive polydnaviruses

Increase of CXCR3+ T cells impairs Th17 cells recruitment in the small intestine mucosa through IFN-g and IL-18 during treated HIV-1 infection

The restoration of CD4+ T cells, especially T-helper type 17 (Th17) cells, remains incomplete in the gut mucosa of most human immunodeficiency virus type 1 (HIV-1)–infected individuals despite sustained antiretroviral therapy (ART). Herein, we report an increase in the absolute number of CXCR3+ T cells in the duodenal mucosa during ART. The frequencies of Th1 and CXCR3+ CD8+ T cells were increased and negatively correlated with CCL20 and CCL25 expression in the mucosa. In ex vivo analyses, we showed that interferon γ, the main cytokine produced by Th1 and effector CD8+ T cells, downregulates the expression of CCL20 and CCL25 by small intestine enterocytes, while it increases the expression of CXCL9/10/11, the ligands of CXCR3. Interleukin 18, a pro-Th1 cytokine produced by enterocytes, also contributes to the downregulation of CCL20 expression and increases interferon γ production by Th1 cells. This could perpetuate an amplification loop for CXCR3-driven Th1 and effector CD8+ T cells recruitment to the gut, while impairing Th17 cells homing through the CCR6-CCL20 axis in treated HIV-1–infected individuals