Variation in susceptibility of African Plasmodium falciparum malaria parasites to TEP1 mediated killing in Anopheles gambiae mosquitoes

Anopheles gambiae s.s. mosquitoes are efficient vectors for Plasmodium falciparum, although variation exists in their susceptibility to infection. This variation depends partly on the thioester-containing protein 1 (TEP1) and TEP depletion results in significantly elevated numbers of oocysts in susceptible and resistant mosquitoes. Polymorphism in the Plasmodium gene coding for the surface protein Pfs47 modulates resistance of some parasite laboratory strains to TEP1-mediated killing. Here, we examined resistance of P. falciparum isolates of African origin (NF54, NF165 and NF166) to TEP1-mediated killing in a susceptible Ngousso and a refractory L3-5 strain of A. gambiae. All parasite clones successfully developed in susceptible mosquitoes with limited evidence for an impact of TEP1 on transmission efficiency. In contrast, NF166 and NF165 oocyst densities were strongly reduced in refractory mosquitoes and TEP1 silencing significantly increased oocyst densities. Our results reveal differences between African P. falciparum strains in their capacity to evade TEP1-mediated killing in resistant mosquitoes. There was no significant correlation between Pfs47 genotype and resistance of a given P. falciparum isolate for TEP1 killing. These data suggest that polymorphisms in this locus are not the sole mediators of immune evasion of African malaria parasites

Intestinal bacterial communities of trypanosome-infected and uninfected Glossina palpalis palpalis from three human African trypanomiasis foci in Cameroon

Glossina sp. the tsetse fly that transmits trypanosomes causing the Human or the Animal African Trypanosomiasis (HAT or AAT) can harbor symbiotic bacteria that are known to play a crucial role in the fly's vector competence. We hypothesized that other bacteria could be present, and that some of them could also influence the fly's vector competence. In this context the objectives of our work were: (a) to characterize the bacteria that compose the G. palpalis palpalis midgut bacteriome, (b) to evidence possible bacterial community differences between trypanosome-infected and non-infected fly individuals from a given AAT and HAT focus or from different foci using barcoded Illumina sequencing of the hypervariable V3-V4 region of the 16S rRNA gene. Forty G. p. palpalis flies, either infected by Trypanosoma congolense or uninfected were sampled from three trypanosomiasis foci in Cameroon. A total of 143 OTUs were detected in the midgut samples. Most taxa were identified at the genus level, nearly 50% at the species level; they belonged to 83 genera principally within the phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Prominent representatives included Wigglesworthia (the fly's obligate symbiont), Serratia, and Enterobacter hormaechei. Wolbachia was identified for the first time in G. p. palpalis. The average number of bacterial species per tsetse sample was not significantly different regarding the fly infection status, and the hierarchical analysis based on the differences in bacterial community structure did not provide a clear clustering between infected and non-infected flies. Finally, the most important result was the evidence of the overall very large diversity of intestinal bacteria which, except for Wigglesworthia, were unevenly distributed over the sampled flies regardless of their geographic origin and their trypanosome infection status

CO(2)hydrogenation using bifunctional catalysts based on K-promoted iron oxide and zeolite: influence of the zeolite structure and crystal size

[EN] In the present manuscript, the influence of the zeolite structure and crystal size on bifunctional tandem catalysts combining K-promoted iron oxide (K/Fe3O4) with different zeolites has been studied for the CO(2)hydrogenation reaction at 320 degrees C and 25 bar. First, to evaluate the influence of the zeolite structure on CO(2)conversion, three different zeolite topologies have been evaluated (BEA, MFI and CHA) with similar Si/Al molar ratios. The combination of K/Fe(3)O(4)with MFI maximizes the formation of aromatic products, while its combination with CHA and BEA increases the C-1-C(4)gas fractions, with a high olefin selectivity. In addition, aromatics and aliphatic hydrocarbons are present in the condensed liquids of the tandem catalysts containing BEA, while no aromatics are observed for those with CHA. These different product selectivities can be ascribed to the different consecutive reactions within the three zeolites, where MFI favors the aromatization of alkenes, and BEA and CHA favor oligomerization/cracking reactions leading to an increase of light olefin yield. Second, the evaluation of the nanosized form of the three proposed zeolite frameworks has also been carried out. The reduction of the particle size allows for increasing light olefin selectivity in all cases as compared to zeolites with larger crystals. Shorter intracrystalline diffusion paths facilitate the egression of light olefins before being involved in consecutive oligomerization reactions. In the particular case of the tandem catalysts with nanosized MFI zeolites, the C-2-C(4)fraction and its olefinicity are increased while maintaining the overall aromatic selectivity comparable to that obtained with micron-sized MFI zeolites.This work was supported by the Spanish Government through "Severo Ochoa" (SEV-2016-0683, MINECO) and RTI2018-101033-B-I00 (MCIU/AEI/FEDER, UE), by the Fundacion Ramon Areces through a research contract (CIVP18A3908) and by Generalitat Valenciana (AICO/2019/060). A. R. F. acknowledges the Spanish Government-MINECO for a FPU scholarship (FPU2017/01521). The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization.García-Hurtado, E.; Rodríguez-Fernández, A.; Moliner Marin, M.; Martínez, C. (2020). CO(2)hydrogenation using bifunctional catalysts based on K-promoted iron oxide and zeolite: influence of the zeolite structure and crystal size. Catalysis Science & Technology. 10(16):5648-5658. https://doi.org/10.1039/d0cy00712aS564856581016Höök, M., & Tang, X. (2013). Depletion of fossil fuels and anthropogenic climate change—A review. Energy Policy, 52, 797-809. doi:10.1016/j.enpol.2012.10.046Dincer, I. (2000). Renewable energy and sustainable development: a crucial review. Renewable and Sustainable Energy Reviews, 4(2), 157-175. doi:10.1016/s1364-0321(99)00011-8Kannan, N., & Vakeesan, D. (2016). Solar energy for future world: - A review. Renewable and Sustainable Energy Reviews, 62, 1092-1105. doi:10.1016/j.rser.2016.05.022Corma, A., Iborra, S., & Velty, A. (2007). Chemical Routes for the Transformation of Biomass into Chemicals. Chemical Reviews, 107(6), 2411-2502. doi:10.1021/cr050989dAbate, S., Barbera, K., Centi, G., Lanzafame, P., & Perathoner, S. (2016). Disruptive catalysis by zeolites. Catalysis Science & Technology, 6(8), 2485-2501. doi:10.1039/c5cy02184gGoeppert, A., Czaun, M., Jones, J.-P., Surya Prakash, G. K., & Olah, G. A. (2014). Recycling of carbon dioxide to methanol and derived products – closing the loop. Chem. Soc. Rev., 43(23), 7995-8048. doi:10.1039/c4cs00122bPrieto, G. (2017). Carbon Dioxide Hydrogenation into Higher Hydrocarbons and Oxygenates: Thermodynamic and Kinetic Bounds and Progress with Heterogeneous and Homogeneous Catalysis. ChemSusChem, 10(6), 1056-1070. doi:10.1002/cssc.201601591Dorner, R. W., Hardy, D. R., Williams, F. W., & Willauer, H. D. (2010). Heterogeneous catalytic CO2 conversion to value-added hydrocarbons. Energy & Environmental Science, 3(7), 884. doi:10.1039/c001514hGao, P., Li, S., Bu, X., Dang, S., Liu, Z., Wang, H., … Sun, Y. (2017). Direct conversion of CO2 into liquid fuels with high selectivity over a bifunctional catalyst. Nature Chemistry, 9(10), 1019-1024. doi:10.1038/nchem.2794WEATHERBEE, G. (1984). Hydrogenation of CO2 on group VIII metals IV. Specific activities and selectivities of silica-supported Co, Fe, and Ru. Journal of Catalysis, 87(2), 352-362. doi:10.1016/0021-9517(84)90196-9Lee, M.-D., Lee, J.-F., Chang, C.-S., & Dong, T.-Y. (1991). Effects of addition of chromium, manganese, or molybdenum to iron catalysts for carbon dioxide hydrogenation. Applied Catalysis, 72(2), 267-281. doi:10.1016/0166-9834(91)85055-zLee, J.-F., Chern, W.-S., Lee, M.-D., & Dong, T.-Y. (2009). Hydrogenation of carbon dioxide on iron catalysts doubly promoted with manganese and potassium. The Canadian Journal of Chemical Engineering, 70(3), 511-515. doi:10.1002/cjce.5450700314Pijolat, M., Perrichon, V., Primet, M., & Bussiere, P. (1982). Hydrocondensation of carbon dioxide over an iron-alumina catalyst: A three-step model. Journal of Molecular Catalysis, 17(2-3), 367-380. doi:10.1016/0304-5102(82)85048-7Guerrero-Ruiz, A., & Rodríguez-Ramos, I. (1985). Hydrogenation of CO2 on carbon-supported nickel and cobalt. Reaction Kinetics and Catalysis Letters, 29(1), 93-99. doi:10.1007/bf02067954Jahangiri, H., Bennett, J., Mahjoubi, P., Wilson, K., & Gu, S. (2014). A review of advanced catalyst development for Fischer–Tropsch synthesis of hydrocarbons from biomass derived syn-gas. Catal. Sci. Technol., 4(8), 2210-2229. doi:10.1039/c4cy00327fRamirez, A., Gevers, L., Bavykina, A., Ould-Chikh, S., & Gascon, J. (2018). Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO2 to Short Chain Olefins. ACS Catalysis, 8(10), 9174-9182. doi:10.1021/acscatal.8b02892Anderson, R. B., Friedel, R. A., & Storch, H. H. (1951). Fischer‐Tropsch Reaction Mechanism Involving Stepwise Growth of Carbon Chain. The Journal of Chemical Physics, 19(3), 313-319. doi:10.1063/1.1748201Griboval-Constant, A., Butel, A., Ordomsky, V. V., Chernavskii, P. A., & Khodakov, A. Y. (2014). Cobalt and iron species in alumina supported bimetallic catalysts for Fischer–Tropsch reaction. Applied Catalysis A: General, 481, 116-126. doi:10.1016/j.apcata.2014.04.047Patzlaff, J., Liu, Y., Graffmann, C., & Gaube, J. (1999). Studies on product distributions of iron and cobalt catalyzed Fischer–Tropsch synthesis. Applied Catalysis A: General, 186(1-2), 109-119. doi:10.1016/s0926-860x(99)00167-2Patzlaff, J., Liu, Y., Graffmann, C., & Gaube, J. (2002). Interpretation and kinetic modeling of product distributions of cobalt catalyzed Fischer–Tropsch synthesis. Catalysis Today, 71(3-4), 381-394. doi:10.1016/s0920-5861(01)00465-5Torres Galvis, H. M., Bitter, J. H., Khare, C. B., Ruitenbeek, M., Dugulan, A. I., & de Jong, K. P. (2012). Supported Iron Nanoparticles as Catalysts for Sustainable Production of Lower Olefins. Science, 335(6070), 835-838. doi:10.1126/science.1215614Kim, H., Choi, D.-H., Nam, S.-S., Choi, M.-J., & Lee, K.-W. (1998). The selective synthesis of lower olefins(C2 - C4) by the CO2 hydrogenation over Iron catalysts promoted with Potassium and supported on ion exchanged(H, K) Zeolite-Y. Advances in Chemical Conversions for Mitigating Carbon Dioxide, Proceedings of the Fourth International Conference on Carbon Dioxide Utilization, 407-410. doi:10.1016/s0167-2991(98)80782-9Nam, S.-S., Kim, H., Kishan, G., Choi, M.-J., & Lee, K.-W. (1999). Catalytic conversion of carbon dioxide into hydrocarbons over iron supported on alkali ion-exchanged Y-zeolite catalysts. Applied Catalysis A: General, 179(1-2), 155-163. doi:10.1016/s0926-860x(98)00322-6Dokania, A., Ramirez, A., Bavykina, A., & Gascon, J. (2018). Heterogeneous Catalysis for the Valorization of CO2: Role of Bifunctional Processes in the Production of Chemicals. ACS Energy Letters, 4(1), 167-176. doi:10.1021/acsenergylett.8b01910Wei, J., Ge, Q., Yao, R., Wen, Z., Fang, C., Guo, L., … Sun, J. (2017). Directly converting CO2 into a gasoline fuel. Nature Communications, 8(1). doi:10.1038/ncomms15174Ramirez, A., Dutta Chowdhury, A., Dokania, A., Cnudde, P., Caglayan, M., Yarulina, I., … Gascon, J. (2019). Effect of Zeolite Topology and Reactor Configuration on the Direct Conversion of CO2 to Light Olefins and Aromatics. ACS Catalysis, 9(7), 6320-6334. doi:10.1021/acscatal.9b01466Mintova, S., Gilson, J.-P., & Valtchev, V. (2013). Advances in nanosized zeolites. Nanoscale, 5(15), 6693. doi:10.1039/c3nr01629cMintova, S., Jaber, M., & Valtchev, V. (2015). Nanosized microporous crystals: emerging applications. Chemical Society Reviews, 44(20), 7207-7233. doi:10.1039/c5cs00210aRimer, J. D., Kumar, M., Li, R., Lupulescu, A. I., & Oleksiak, M. D. (2014). Tailoring the physicochemical properties of zeolite catalysts. Catal. Sci. Technol., 4(11), 3762-3771. doi:10.1039/c4cy00858hDíaz-Rey, M. R., Paris, C., Martínez-Franco, R., Moliner, M., Martínez, C., & Corma, A. (2017). Efficient Oligomerization of Pentene into Liquid Fuels on Nanocrystalline Beta Zeolites. ACS Catalysis, 7(9), 6170-6178. doi:10.1021/acscatal.7b00817Gallego, E. M., Paris, C., Díaz-Rey, M. R., Martínez-Armero, M. E., Martínez-Triguero, J., Martínez, C., … Corma, A. (2017). Simple organic structure directing agents for synthesizing nanocrystalline zeolites. Chemical Science, 8(12), 8138-8149. doi:10.1039/c7sc02858jGallego, E. M., Li, C., Paris, C., Martín, N., Martínez-Triguero, J., Boronat, M., … Corma, A. (2018). Making Nanosized CHA Zeolites with Controlled Al Distribution for Optimizing Methanol-to-Olefin Performance. Chemistry - A European Journal, 24(55), 14631-14635. doi:10.1002/chem.201803637Martínez-Franco, R., Paris, C., Martínez-Armero, M. E., Martínez, C., Moliner, M., & Corma, A. (2016). High-silica nanocrystalline Beta zeolites: efficient synthesis and catalytic application. Chemical Science, 7(1), 102-108. doi:10.1039/c5sc03019fCamblor, M. A., Corma, A., & Valencia, S. (1998). Characterization of nanocrystalline zeolite Beta. Microporous and Mesoporous Materials, 25(1-3), 59-74. doi:10.1016/s1387-1811(98)00172-3Boronat, M., & Corma, A. (2019). What Is Measured When Measuring Acidity in Zeolites with Probe Molecules? ACS Catalysis, 9(2), 1539-1548. doi:10.1021/acscatal.8b04317Ramirez, A., Ould‐Chikh, S., Gevers, L., Chowdhury, A. D., Abou‐Hamad, E., Aguilar‐Tapia, A., … Gascon, J. (2019). Tandem Conversion of CO 2 to Valuable Hydrocarbons in Highly Concentrated Potassium Iron Catalysts. ChemCatChem, 11(12), 2879-2886. doi:10.1002/cctc.201900762Arora, S. S., Shi, Z., & Bhan, A. (2019). Mechanistic Basis for Effects of High-Pressure H2 Cofeeds on Methanol-to-Hydrocarbons Catalysis over Zeolites. ACS Catalysis, 9(7), 6407-6414. doi:10.1021/acscatal.9b00969Dusselier, M., & Davis, M. E. (2018). Small-Pore Zeolites: Synthesis and Catalysis. Chemical Reviews, 118(11), 5265-5329. doi:10.1021/acs.chemrev.7b00738Moliner, M., Martínez, C., & Corma, A. (2013). Synthesis Strategies for Preparing Useful Small Pore Zeolites and Zeotypes for Gas Separations and Catalysis. Chemistry of Materials, 26(1), 246-258. doi:10.1021/cm4015095Tang, X., Zhou, H., Qian, W., Wang, D., Jin, Y., & Wei, F. (2008). High Selectivity Production of Propylene from n-Butene: Thermodynamic and Experimental Study Using a Shape Selective Zeolite Catalyst. Catalysis Letters, 125(3-4), 380-385. doi:10.1007/s10562-008-9564-8Weber, J. L., Dugulan, I., de Jongh, P. E., & de Jong, K. P. (2018). Bifunctional Catalysis for the Conversion of Synthesis Gas to Olefins and Aromatics. ChemCatChem, 10(5), 1107-1112. doi:10.1002/cctc.201701667Vermeiren, W., & Gilson, J.-P. (2009). Impact of Zeolites on the Petroleum and Petrochemical Industry. Topics in Catalysis, 52(9), 1131-1161. doi:10.1007/s11244-009-9271-8Tsai, T. (1999). Disproportionation and transalkylation of alkylbenzenes over zeolite catalysts. Applied Catalysis A: General, 181(2), 355-398. doi:10.1016/s0926-860x(98)00396-

Midgut microbiota of the malaria mosquito vector Anopheles gambiae and Interactions with plasmodium falciparum Infection

The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission.Institut de Recherche pour le Developpement (IRD); French Agence Nationale pour la Recherche [ANR-11-BSV7-009-01]; European Community [242095, 223601]info:eu-repo/semantics/publishedVersio

A framework for scabies control.

Scabies is a neglected tropical disease (NTD) that causes a significant health burden, particularly in disadvantaged communities and where there is overcrowding. There is emerging evidence that ivermectin-based mass drug administration (MDA) can reduce the prevalence of scabies in some settings, but evidence remains limited, and there are no formal guidelines to inform control efforts. An informal World Health Organization (WHO) consultation was organized to find agreement on strategies for global control. The consultation resulted in a framework for scabies control and recommendations for mapping of disease burden, delivery of interventions, and establishing monitoring and evaluation. Key operational research priorities were identified. This framework will allow countries to set control targets for scabies as part of national NTD strategic plans and develop control strategies using MDA for high-prevalence regions and outbreak situations. As further evidence and experience are collected and strategies are refined over time, formal guidelines can be developed. The control of scabies and the reduction of the health burden of scabies and associated conditions will be vital to achieving the targets set in WHO Roadmap for NTDs for 2021 to 2030 and the Sustainable Development Goals

Polymorphisms in Anopheles gambiae Immune Genes Associated with Natural Resistance to Plasmodium falciparum

Many genes involved in the immune response of Anopheles gambiae, the main malaria vector in Africa, have been identified, but whether naturally occurring polymorphisms in these genes underlie variation in resistance to the human malaria parasite, Plasmodium falciparum, is currently unknown. Here we carried out a candidate gene association study to identify single nucleotide polymorphisms (SNPs) associated with natural resistance to P. falciparum. A. gambiae M form mosquitoes from Cameroon were experimentally challenged with three local wild P. falciparum isolates. Statistical associations were assessed between 157 SNPs selected from a set of 67 A. gambiae immune-related genes and the level of infection. Isolate-specific associations were accounted for by including the effect of the isolate in the analysis. Five SNPs were significantly associated to the infection phenotype, located within or upstream of AgMDL1, CEC1, Sp PPO activate, Sp SNAKElike, and TOLL6. Low overall and local linkage disequilibrium indicated high specificity in the loci found. Association between infection phenotype and two SNPs was isolate-specific, providing the first evidence of vector genotype by parasite isolate interactions at the molecular level. Four SNPs were associated to either oocyst presence or load, indicating that the genetic basis of infection prevalence and intensity may differ. The validity of the approach was verified by confirming the functional role of Sp SNAKElike in gene silencing assays. These results strongly support the role of genetic variation within or near these five A. gambiae immune genes, in concert with other genes, in natural resistance to P. falciparum. They emphasize the need to distinguish between infection prevalence and intensity and to account for the genetic specificity of vector-parasite interactions in dissecting the genetic basis of Anopheles resistance to human malaria

Interactive cost of Plasmodium infection and insecticide resistance in the malaria vector Anopheles gambiae

International audienceInsecticide resistance raises concerns for the control of vector-borne diseases. However, its impact on parasite transmission could be diverse when considering the ecological interactions between vector and parasite. Thus we investigated the fitness cost associated with insecticide resistance and Plasmodium falciparum infection as well as their interactive cost on Anopheles gambiae survival and fecundity. In absence of infection, we observed a cost on fecundity associated with insecticide resistance. However, survival was higher for mosquito bearing the kdr mutation and equal for those with the ace-1(R) mutation compared to their insecticide susceptible counterparts. Interestingly, Plasmodium infection reduced survival only in the insecticide resistant strains but not in the susceptible one and infection was associated with an increase in fecundity independently of the strain considered. This study provides evidence for a survival cost associated with infection by Plasmodium parasite only in mosquito selected for insecticide resistance. This suggests that the selection of insecticide resistance mutation may have disturbed the interaction between parasites and vectors, resulting in increased cost of infection. Considering the fitness cost as well as other ecological aspects of this natural mosquito-parasite combination is important to predict the epidemiological impact of insecticide resistance