Field optimization of pheromone traps for monitoring and controlling cocoa mirids, Sahlbergella singularis

In Cameroon, pheromone traps appear interesting to monitor or even control Sahlbergella singularis populations on cocoa farms. The efficiency of traps baited with pheromones relies on a good knowledge of both visual and olfactory stimuli that attract cocoa mirids and on appropriate trap deployment in cocoa plantations. The aim of this preliminary study is first to compare the attractiveness of traps of different colors and baited with different pheromone blends. To achieve this purpose, we monitored a total of 90 traps of 3 different colors (30 red, 30 yellow and 30 white) and baited with 2 different pheromone blends, deployed in ten 1-ha plots (100 x 100m) PVC tubular traps were monitored from March on a weekly basis. Simultaneously, experiments in flight tunnel were conducted in the laboratory to confirm trends observed in the field. Secondly, to better understand how trap deployment influences mirid capture rate, we tested 3 trap densities in a total of twenty one 1-ha plots (100 x 100m) which received different treatments: 7 plots with a high trap density (16 traps ha-1), 7 plots with a medium trap density (9 traps ha-1) and 7 plots with a low trap density (4 traps ha-1). Traps were monitored on a weekly basis. Also, mirid populations and damage were assessed in each plot twice a year. Seven plantations with no trap were sprayed with insecticide according to spraying recommendations and were also monitored to evaluate the productivity gain or loss between the two control methods. Understanding the factors involved in oriented movements of mirids in the field, will help to formulate relevant recommendations to improve integrated management of S. singularis and potentially to reduce the economical cost of control strategies. (Résumé d'auteur

Formulation des conidies de Trichoderma Asperellum sous forme de dispersion huileuse pour la lutte biologique contre Phytophthora Megakarya, agent responsable de la pourritutre brune des fruits du cacaoyer (Theobroma Cacao L.) au Cameroun

La pourriture brune des fruits du cacaoyer causée par Phytophthora megakarya au Cameroun est à l'origine des pertes importantes de rendement L'utilisation des conidies de Trichoderma asperellum formulées sous forme de poudre mouillable pour lutter contre l'agent responsable de la pourriture brune des fruits a montré des résultats prometteurs mais inconstants. L'objectif de cette étude était de produire une formulation des conidies de Trichoderma asperellum sous forme de dispersion huileuse afin d'améliorer l'efficacité de cet agent de lutte biologique. Dix formulations sous forme de dispersion huileuse ont été développées et caractérisées suivant la méthode CIPAC. La dispersion huileuse F8 composée de 75,5% d'huile de soja, 15% de Tensiofix NTM, 5% de Tensiofix 869, 4.5% de glucose et de 2,7 x 107 conidies de T. asperellum ml-1 s'est révélée comme étant la meilleure formulation sur la base de ses propriétés physiques (stabilité: 75%; viscosité: 106.01 cps). Par ailleurs, le taux de germination des conidies de T. asperellum dans cette formulation après 26 semaines de stockage à 4°C était de 46%. Cette formulation a donc été sélectionnée et son efficacité biologique contre P. megakarya a été évaluée in vitro et in vivo. Les résultats obtenus à l'issu des tests sur milieu artificiel ont montré que les conidies de T. aspere/lum sous forme formulée réduisaient significativement le taux de croissance du pathogène (P<0.05). Cette observation a par la suite été confirmée lors des tests réalisés sur cabosses détachées où la formulation sous forme de dispersion huileuse des conidies de T. aspereflum a inhilbé à l00% le développement de la maladie. En tout, ces résultats suggèrent que la formulation des conidies de T. asperellum sous forme de dispersion huileuse pour constituer une alternative viable à la lutte chimique contre la pourriture des fruits du cacaoyer. Cependant, la confirmation de ce potentiel requiert préalablement la réalisation des tests en champs en utilisant cette formulation. (Résumé d'auteur

Cocoa variety assessment in on-farm progeny trials in Cameroon

In Cameroon, IRAD and CIRAD have collaboratively set up and implemented a participatory breeding program since 2006, consisting in the assessment of cocoa varieties under cocoa farm conditions. The present communication describes the results obtained so far on progenies compared in three progeny trials set up in 2006 and 2007. The first trial, set up in 2006, is composed of 12 trial plots, and allows the comparative assessment of nine progenies which are currently released to farmers. Data analyses performed on yield and establishment ability showed high performances for the progeny issued from the cross IMC 67 * SNK 109 and low performances for the one issued from the cross T 79/501 * SNK 64. Data analyses performed on mirid damage scores revealed a higher level of susceptibility for the progeny issued from the cross IMC 67 * SNK 109 and a lower one for the progenies issued from the crosses T 79/501 * SNK 64 and IMC 67 * SNK 64. The assessed progenies showed a mean weight of one bean of dried cocoa ranging between 1,17g (SCA 12 * SNK 16) and 1,52g (SNK 109 * IMC 67). The second progeny trial, set up in 2006, composed of four trial plots, allows the comparison between 16 cocoa progenies, issued from: commercially released progenies, progenies recently created at IRAD, progenies issued from on farm selection of promising trees. Data analyses show a higher level of yield for the commercially released progenies and a lower level for progenies issued from on farm selection. Data analyses of tolerance to Phytophthora megakarya, assessed using a leaf inoculation test showed a slightly higher level of tolerance for the progenies recently created at IRAD. The third trial set up in 2007, is composed of six trial plots and allows the comparison between eight progenies: one recently created at IRAD, three commercially released progenies, two issued from on farm selection of promising trees, two issued from trees chosen at random in cocoa farms set up with traditional (german cocoa) or commercial cocoa progenies. Data analyses show a high level of yield for the progeny recently created at IRAD (T 60/887 * POUND 7) and a low level for the progeny issued from traditional varieties (german cocoa). (Résumé d'auteur

Marine microbial biodiversity, bioinformatics and biotechnology (M2B3) data reporting and service standards

Contextual data collected concurrently with molecular samples are critical to the use of metagenomics in the fields of marine biodiversity, bioinformatics and biotechnology. We present here Marine Microbial Biodiversity, Bioinformatics and Biotechnology (M2B3) standards for “Reporting” and “Serving” data. The M2B3 Reporting Standard (1) describes minimal mandatory and recommended contextual information for a marine microbial sample obtained in the epipelagic zone, (2) includes meaningful information for researchers in the oceanographic, biodiversity and molecular disciplines, and (3) can easily be adopted by any marine laboratory with minimum sampling resources. The M2B3 Service Standard defines a software interface through which these data can be discovered and explored in data repositories. The M2B3 Standards were developed by the European project Micro B3, funded under 7th Framework Programme “Ocean of Tomorrow”, and were first used with the Ocean Sampling Day initiative. We believe that these standards have value in broader marine science

Autism Spectrum Disorder in an Unselected Cohort of Children with Neurofibromatosis Type 1 (NF1)

In a non-selected sample of children with Neurofibromatosis type 1 (NF1) the prevalence rate of autism spectrum disorder (ASD) and predictive value of an observational (ADOS)—and questionnaire-based screening instrument were assessed. Complete data was available for 128 children. The prevalence rate for clinical ASD was 10.9%, which is clearly higher than in the general population. This prevalence rate is presumably more accurate than in previous studies that examined children with NF1 with an ASD presumption or solely based on screening instruments. The combined observational- and screening based classifications demonstrated the highest positive predictive value for DSM-IV diagnosis, highlighting the importance of using both instruments in children with NF1

Fixation and Spread of Somatic Mutations in Adult Human Colonic Epithelium

We investigated the means and timing by which mutations become fixed in the human colonic epithelium by visualizing somatic clones and mathematical inference. Fixation requires two sequential steps. First, one of approximately seven active stem cells residing within each colonic crypt has to be mutated. Second, the mutated stem cell has to replace neighbors to populate the entire crypt in a process that takes several years. Subsequent clonal expansion due to crypt fission is infrequent for neutral mutations (around 0.7% of all crypts undergo fission in a single year). Pro-oncogenic mutations subvert both stem cell replacement to accelerate fixation and clonal expansion by crypt fission to achieve high mutant allele frequencies with age. The benchmarking of these behaviors allows the advantage associated with different gene-specific mutations to be compared irrespective of the cellular mechanisms by which they are conferred

Stretching the Rules: Monocentric Chromosomes with Multiple Centromere Domains

The centromere is a functional chromosome domain that is essential for faithful chromosome segregation during cell division and that can be reliably identified by the presence of the centromere-specific histone H3 variant CenH3. In monocentric chromosomes, the centromere is characterized by a single CenH3-containing region within a morphologically distinct primary constriction. This region usually spans up to a few Mbp composed mainly of centromere-specific satellite DNA common to all chromosomes of a given species. In holocentric chromosomes, there is no primary constriction; the centromere is composed of many CenH3 loci distributed along the entire length of a chromosome. Using correlative fluorescence light microscopy and high-resolution electron microscopy, we show that pea (Pisum sativum) chromosomes exhibit remarkably long primary constrictions that contain 3-5 explicit CenH3-containing regions, a novelty in centromere organization. In addition, we estimate that the size of the chromosome segment delimited by two outermost domains varies between 69 Mbp and 107 Mbp, several factors larger than any known centromere length. These domains are almost entirely composed of repetitive DNA sequences belonging to 13 distinct families of satellite DNA and one family of centromeric retrotransposons, all of which are unevenly distributed among pea chromosomes. We present the centromeres of Pisum as novel ``meta-polycentric'' functional domains. Our results demonstrate that the organization and DNA composition of functional centromere domains can be far more complex than previously thought, do not require single repetitive elements, and do not require single centromere domains in order to segregate properly. Based on these findings, we propose Pisum as a useful model for investigation of centromere architecture and the still poorly understood role of repetitive DNA in centromere evolution, determination, and function

Preferential MGMT hypermethylation in SDH-deficient wild-type GIST

AIMS: Wild-type gastrointestinal stromal tumours (wtGIST) are frequently caused by inherited pathogenic variants, or somatic alterations in the succinate dehydrogenase subunit genes (SDHx). Succinate dehydrogenase is a key enzyme in the citric acid cycle. SDH deficiency caused by SDHx inactivation leads to an accumulation of succinate, which inhibits DNA and histone demethylase enzymes, resulting in global hypermethylation. Epigenetic silencing of the DNA repair gene MGMT has proven utility as a positive predictor of the therapeutic efficacy of the alklyating drug temozolomide (TMZ) in tumours such as glioblastoma multiforme. The aim of this study was to examine MGMT promoter methylation status in a large cohort of GIST. METHODS: MGMT methylation analysis was performed on 65 tumour samples including 47 wtGIST (33 SDH-deficient wtGIST and 11 SDH preserved wtGIST) and 21 tyrosine kinase (TK) mutant GIST. RESULTS: MGMT promoter methylation was detected in 8 cases of SDH-deficient (dSDH) GIST but in none of the 14 SDH preserved wild-type GIST or 21 TK mutant GIST samples analysed. Mean MGMT methylation was significantly higher (p 0.0449) and MGMT expression significantly lower (p<0.0001) in dSDH wtGIST compared with TK mutant or SDH preserved GIST. No correlation was identified between SDHx subunit gene mutations or SDHC epimutation status and mean MGMT methylation levels. CONCLUSION: MGMT promoter hypermethylation occurs exclusively in a subset of dSDH wtGIST. Data from this study support testing of tumour MGMT promoter methylation in patients with dSDH wtGIST to identify those patients who may benefit from most from TMZ therapy

Pesticides use in cocoa sector in Cameroon: characterization of supply source, nature of actives ingredients, fashion and reasons for their utilization

The chemical control is the widely control method applied in Cameroon for pests and diseases by all the cocoa producers without technical suitable assistance by the State as before 1980’S. However, it is known that farmers have less knowledge on the good pesticides use for the control of a specific pest. The objective of this study was to provide insight in current pesticide use in the cocoa sector in Cameroon. A stratified sampling scheme was used. A total of 251 cocoa farmers, 20 post-harvest cocoa traders and 37 chemical retailers were randomly selected and interviewed. The study showed that 35 different chemicals were marketed in Cameroon for use in cocoa: 4 herbicides, 11 fungicides and 20 insecticides. Of 251 farmers consulted, 96.8% said that they use pesticides on their farms while 3.2% did not. Fungicides were used most often by farmers 61.8%) followed by insecticides (38.2%). Eight active ingredients although, officially banned, were still being used on cocoa farms. Over 77% of farmers do not respect the official spray recommendations for chemicals. Moreover, 64% do not respect recommended doses. Two main pesticide-supply-pathways exist in Cameroon: a legal and illegal supply chain, which provides 51% of pesticides to cocoa farmers, resulting in an estimated loss of value added tax for the Cameroonian government of about 550 000 to 2.4 million Euros per year. These results suggest that improved pests and diseases control by the State and raising farmer awareness about pesticide use in cocoa could greatly attribute to more sustainable cocoa economy in Cameroon.Keywords : Cocoa, pesticides, insecticides, fungicides, Cameroon

Value, but high costs in post-deposition data curation

Discoverability of sequence data in primary data archives is proportional to the richness of contextual information associated with the data. Here, we describe an exercise in the improvement of contextual information surrounding sample records associated with metagenomics sequence reads available in the European Nucleotide Archive. We outline the annotation process and summarize findings of this effort aimed at increasing usability of publicly available environmental data. Furthermore, we emphasize the benefits of such an exercise and detail its costs. We conclude that such a third party annotation approach is expensive and has value as an element of curation, but should form only part of a more sustainable submitter-driven approach