Comparison of Two Mathematical Models for Greenhouse Gas Emission from Membrane Bioreactors

In this study two mathematical models (Model I and Model II), able to predict the nitrous oxide (N2O) and carbon dioxide (CO2) emission from an University Cape Town (UCT) \u2013 membrane bioreactor (MBR) plant, have been compared. Model I considers the N2O production only during the denitrification. Model II takes into account the two ammonia-oxidizing bacteria (AOB) formation pathways for N2O. Both models were calibrated adopting real data. Results highlight that Model II had a better capability of reproducing the measured data especially in terms of N2O model outputs. Indeed, the average efficiency related to the N2O model outputs was equal to 0.3 and 0.38 for Model I and Model II respectively

Zika vector competence data reveals risks of outbreaks: the contribution of the European ZIKAlliance project

First identified in 1947, Zika virus took roughly 70 years to cause a pandemic unusually associated with virus-induced brain damage in newborns. Zika virus is transmitted by mosquitoes, mainly Aedes aegypti, and secondarily, Aedes albopictus, both colonizing a large strip encompassing tropical and temperate regions. As part of the international project ZIKAlliance initiated in 2016, 50 mosquito populations from six species collected in 12 countries were experimentally infected with different Zika viruses. Here, we show that Ae. aegypti is mainly responsible for Zika virus transmission having the highest susceptibility to viral infections. Other species play a secondary role in transmission while Culex mosquitoes are largely non-susceptible. Zika strain is expected to significantly modulate transmission efficiency with African strains being more likely to cause an outbreak. As the distribution of Ae. aegypti will doubtless expand with climate change and without new marketed vaccines, all the ingredients are in place to relive a new pandemic of Zika.info:eu-repo/semantics/publishedVersio

Zika vector competence data reveals risks of outbreaks: the contribution of the European ZIKAlliance project

First identified in 1947, Zika virus took roughly 70 years to cause a pandemic unusually associated with virus-induced brain damage in newborns. Zika virus is transmitted by mosquitoes, mainly Aedes aegypti, and secondarily, Aedes albopictus, both colonizing a large strip encompassing tropical and temperate regions. As part of the international project ZIKAlliance initiated in 2016, 50 mosquito populations from six species collected in 12 countries were experimentally infected with different Zika viruses. Here, we show that Ae. aegypti is mainly responsible for Zika virus transmission having the highest susceptibility to viral infections. Other species play a secondary role in transmission while Culex mosquitoes are largely non-susceptible. Zika strain is expected to significantly modulate transmission efficiency with African strains being more likely to cause an outbreak. As the distribution of Ae. aegypti will doubtless expand with climate change and without new marketed vaccines, all the ingredients are in place to relive a new pandemic of Zika

Cytoplasmic Incompatibility as a Means of Controlling Culex pipiens quinquefasciatus Mosquito in the Islands of the South-Western Indian Ocean

The use of the bacterium Wolbachia is an attractive alternative method to control vector populations. In mosquitoes, as in members of the Culex pipiens complex, Wolbachia induces a form of embryonic lethality called cytoplasmic incompatibility, a sperm-egg incompatibility occurring when infected males mate either with uninfected females or with females infected with incompatible Wolbachia strain(s). Here we explore the feasibility of the Incompatible Insect Technique (IIT), a species-specific control approach in which field females are sterilized by inundative releases of incompatible males. We show that the Wolbachia wPip(Is) strain, naturally infecting Cx. p. pipiens mosquitoes from Turkey, is a good candidate to control Cx. p. quinquefasciatus populations on four islands of the south-western Indian Ocean (La Réunion, Mauritius, Grande Glorieuse and Mayotte). The wPip(Is) strain was introduced into the nuclear background of Cx. p. quinquefasciatus mosquitoes from La Réunion, leading to the LR[wPip(Is)] line. Total embryonic lethality was observed in crosses between LR[wPip(Is)] males and all tested field females from the four islands. Interestingly, most crosses involving LR[wPip(Is)] females and field males were also incompatible, which is expected to reduce the impact of any accidental release of LR[wPip(Is)] females. Cage experiments demonstrate that LR[wPip(Is)] males are equally competitive with La Réunion males resulting in demographic crash when LR[wPip(Is)] males were introduced into La Réunion laboratory cages. These results, together with the geographic isolation of the four south-western Indian Ocean islands and their limited land area, support the feasibility of an IIT program using LR[wPip(Is)] males and stimulate the implementation of field tests for a Cx. p. quinquefasciatus control strategy on these islands

Local selection in the presence of high levels of gene flow: Evidence of heterogeneous insecticide selection pressure across Ugandan Culex quinquefasciatus populations

Background: Culex quinquefasciatus collected in Uganda, where no vector control interventions directly targeting this species have been conducted, was used as a model to determine if it is possible to detect heterogeneities in selection pressure driven by insecticide application targeting other insect species. Methodology/Principal findings: Population genetic structure was assessed through microsatellite analysis, and the impact of insecticide pressure by genotyping two target-site mutations, Vgsc-1014F of the voltage-gated sodium channel target of pyrethroid and DDT insecticides, and Ace1-119S of the acetylcholinesterase gene, target of carbamate and organophosphate insecticides. No significant differences in genetic diversity were observed among populations by microsatellite markers with HE ranging from 0.597 to 0.612 and low, but significant, genetic differentiation among populations (FST = 0.019, P = 0.001). By contrast, the insecticide-resistance markers display heterogeneous allelic distributions with significant differences detected between Central Ugandan (urban) populations relative to Eastern and Southwestern (rural) populations. In the central region, a frequency of 62% for Vgsc-1014F, and 32% for the Ace1-119S resistant allele were observed. Conversely, in both Eastern and Southwestern regions the Vgsc-1014F alleles were close to fixation, whilst Ace1-119S allele frequency was 12% (although frequencies may be underestimated due to copy number variation at both loci). Conclusions/Significance: Taken together, the microsatellite and both insecticide resistance target-site markers provide evidence that in the face of intense gene flow among populations, disjunction in resistance frequencies arise due to intense local selection pressures despite an absence of insecticidal control interventions targeting Culex

X-exome sequencing of 405 unresolved families identifies seven novel intellectual disability genes

X-linked intellectual disability (XLID) is a clinically and genetically heterogeneous disorder. During the past two decades in excess of 100 X-chromosome ID genes have been identified. Yet, a large number of families mapping to the X-chromosome remained unresolved suggesting that more XLID genes or loci are yet to be identified. Here, we have investigated 405 unresolved families with XLID. We employed massively parallel sequencing of all X-chromosome exons in the index males. The majority of these males were previously tested negative for copy number variations and for mutations in a subset of known XLID genes by Sanger sequencing. In total, 745 X-chromosomal genes were screened. After stringent filtering, a total of 1297 non-recurrent exonic variants remained for prioritization. Co-segregation analysis of potential clinically relevant changes revealed that 80 families (20%) carried pathogenic variants in established XLID genes. In 19 families, we detected likely causative protein truncating and missense variants in 7 novel and validated XLID genes (CLCN4, CNKSR2, FRMPD4, KLHL15, LAS1L, RLIM and USP27X) and potentially deleterious variants in 2 novel candidate XLID genes (CDK16 and TAF1). We show that the CLCN4 and CNKSR2 variants impair protein functions as indicated by electrophysiological studies and altered differentiation of cultured primary neurons from Clcn4−/− mice or after mRNA knock-down. The newly identified and candidate XLID proteins belong to pathways and networks with established roles in cognitive function and intellectual disability in particular. We suggest that systematic sequencing of all X-chromosomal genes in a cohort of patients with genetic evidence for X-chromosome locus involvement may resolve up to 58% of Fragile X-negative cases

Transcriptomic analysis of insecticide resistance in the lymphatic filariasis vector Culex quinquefasciatus

Culex quinquefasciatus plays an important role in transmission of vector-borne diseases of public health importance, including lymphatic filariasis (LF), as well as many arboviral diseases. Currently, efforts to tackle C. quinquefasciatus vectored diseases are based on either mass drug administration (MDA) for LF, or insecticide-based interventions. Widespread and intensive insecticide usage has resulted in increased resistance in mosquito vectors, including C. quinquefasciatus. Herein, the transcriptome profile of Ugandan bendiocarb-resistant C. quinquefasciatus was explored to identify candidate genes associated with insecticide resistance. High levels of insecticide resistance were observed for five out of six insecticides tested, with the lowest mortality (0.97%) reported to permethrin, while for DDT, lambdacyhalothrin, bendiocarb and deltamethrin the mortality rate ranged from 1.63–3.29%. Resistance to bendiocarb in exposed mosquitoes was marked, with 2.04% mortality following 1 h exposure and 58.02% after 4 h. Genotyping of the G119S Ace-1 target site mutation detected a highly significant association (p 8-fold increase vs unexposed controls). These results provide evidence that bendiocarb resistance in Ugandan C. quinquefasciatus is mediated by both target-site mechanisms and over-expression of detoxification enzymes

A two pathway model for N2O emissions by ammonium oxidizing bacteria supported by the NO/N2O variation

International audienceIn this work, a new model for nitritation combining two N2O emission pathways was confronted with both NO and N2O measurements during nitrification. The model was calibrated with batch experiments and validated with long-term data collected in a sequencing batch reactor (SBR). A good prediction of the evolution of N2O emissions for a varying level of nitrite was demonstrated. The NO/N30/11/22O ratio was shown to vary during nitritation depending on the nitrite level. None of the models based on a single pathway could describe this variation of the NO/N2O ratio. In contrast, the 2 pathway model was capable of describing the trends observed for the NO/N2O ratio and gave better predictions of N2O emission factors. The model confirmed that the decrease of the NO/N2O ratio can be explained by an increase of the ND pathway to the detriment of the NN pathway. The ND pathway was systematically the predominant pathway during nitritation. The combined effect 2 of nitrite (or free nitrous acid) and dissolved oxygen (DO) on the contribution of each pathway was in agreement with practical observations and the literature