Project description:Plasmodium parasites within mosquitoes are exposed to various physiological processes, such as blood meal digestion activity, the gonotrophic cycle, and host responses preventing the entry of parasites into the midgut wall. However, when in vitro-cultured ookinetes are injected into the hemocoel of mosquitoes, Plasmodium parasites are not affected by the vertebrate host’s blood contents and do not pass through the midgut epithelial cells. This infection method might aid in identifying mosquito-derived factors affecting Plasmodium development within mosquitoes. This study investigated novel mosquito-derived molecules related to parasite development in Anopheles mosquitoes. We injected in vitro-cultured Plasmodium berghei (ANKA strain) ookinetes into female and male Anopheles stephensi (STE2 strain) mosquitoes and found that the oocyst number was significantly higher in males than in females, suggesting that male mosquitoes better support the development of parasites. Next, RNA-seq analysis was performed on the injected female and male mosquitoes to identify genes exhibiting changes in expression. Five genes with different expression patterns between sexes and greatest expression changes were identified as being potentially associated with Plasmodium infection. Two of the five genes also showed expression changes with infection by blood-feeding, indicating that these genes could affect the development of Plasmodium parasites in mosquitoes.
Project description:Transcriptional responses in the gut of the main malaria vector Anopheles gambiae following oral bacterial infection with the entomopathogen Serratia marcescens were identified using DNA microarrays. S. marcescens is a common member of the mosquito gut microbiota, found in both laboratory reared and field collected mosquitoes, that can be potentially pathogenic as in Drosophila (Nehme et al., 2007), while it has been shown to influence the outcome of Plasmodium infections (Bando et al., 2013). S. marcescens belongs to the Enterobacteriaceae family, members of which have been shown to influence malaria transmission dynamics (Cirimotich et al., 2011, Boissiere et al., 2012). To further investigate the interactions between S. marcescens and the mosquito host, likely to shape, directly or indirectly, malaria transmission dynamics, An. gambiae mosquitoes, from the recently established N'gousso M form laboratory colony that retains much of the genetic variation of field mosquitoes, were antibiotic treated for 5 days and subsequently orally infected with the Db11-GFP strain of S. marcescens. Bacteria-fed mosquitoes were selected 2 days post infection, and, 3 days post infection, guts from bacteria-fed mosquitoes were dissected. Uninfected control mosquitoes were treated in the same way. Differential expression in the gut of S. marcescens infected mosquitoes, compared to uninfected controls, was identified by hybridizing labelled complementary RNA, derived from total RNA extracted from the respective gut pools, in customized Agilent 4x44k gene expression microarrays, comprising oligonucleotide probes encompassing all An. gambiae annotated genes of the AgamP3.6 release, with each probe represented in duplicate.
Project description:Transmission of malaria is dependent on the successful completion of the Plasmodium lifecycle in the Anopheles vector. Major obstacles are encountered in the midgut tissue, where most parasites are killed by the mosquito’s immune system. In the present study, DNA microarray analyses have been used to compare Anopheles gambiae responses to invasion of the midgut epithelium by the ookinete stage of the human pathogen Plasmodium falciparum and the rodent experimental model pathogen P. berghei. Invasion by P. berghei had a more profound impact on the mosquito transcriptome, including a variety of functional gene classes, while P. falciparum elicited a broader immune response at the gene transcript level. Ingestion of human malaria-infected blood lacking invasive ookinetes also induced a variety of immune genes, including several anti-Plasmodium factors. By comparing gene expression patterns between carcassess or guts of mosquitoes that fed on a P. falciparum or P. berghei wt and mosquitoes that fed on invasion incapable strains we gain information on the A. gambiae transcriptional responses to the invading ookinete at 24 hours after feeding. By comparing gene expression patterns between carcassess or guts of mosquitoes that fed on a P. falciparum ookinete invasion incapable strain and mosquitoes that fed on non-infected blood we gain information on the A. gambiae transcriptional responses to malaria infected blood in absence of ookinete invasion at 24 hours after feeding. By comparing gene expression patterns between mosquitoes at 4 hours after being injected with either E. coli or S. aureus and mosquitoes injected with sterile PBS we gain information on the mosquito's transcriptional response to these bacterial challenges.
Project description:Identification of genes associated with bendiocarb resistance. Mosquitoes collected as larvae from Nagongera and Kihihi, Uganda. Bendiocarb-resistant and unexposed female mosquitoes selected using standard WHO tube bioassays. RNA was extracted from pools of five individuals identified as An. gambiae s.s. Insecticide-susceptible mosquitoes from the Kisumu strain were included as controls. RNA hybridized in an interwoven loop design to compare four biological replicates each of resistant, unexposed, and laboratory mosquitoes.
Project description:Transcriptional profiling of three Anopeheles arabiensis strains: (i) DDT resistant mosquitoes from the city of Bobo Dioulasso (ii) mosquitoes from Bobo Dioulasso not exposed to DDT (iii) a laboratory DDT-susceptible strain.
Project description:Adult mosquitoes were fed blood containing 1e7 PFU WNV (kunjin strain) containing +/- 170 pM bovine insulin for 24 h. We then performed gene expression profiling analysis using data obtained from RNA-seq.
Project description:Use of the bacterium Wolbachia is an innovative new strategy designed to break the cycle of dengue transmission. There are two main mechanisms by which Wolbachia could achieve this: by reducing the level of dengue virus in the mosquito and/or by shortening the host mosquito's lifespan. However, although Wolbachia shortens the lifespan, it also gives a breeding advantage which results in complex population dynamics. This study focuses on the development of a mathematical model to quantify the effect on human dengue cases of introducing Wolbachia into the mosquito population. The model consists of a compartment-based system of first-order differential equations; seasonal forcing in the mosquito population is introduced through the adult mosquito death rate. The analysis focuses on a single dengue outbreak typical of a region with a strong seasonally-varying mosquito population. We found that a significant reduction in human dengue cases can be obtained provided that Wolbachia-carrying mosquitoes persist when competing with mosquitoes without Wolbachia. Furthermore, using the Wolbachia strain WMel reduces the mosquito lifespan by at most 10% and allows them to persist in competition with non-Wolbachia-carrying mosquitoes. Mosquitoes carrying the WMelPop strain, however, are not likely to persist as it reduces the mosquito lifespan by up to 50%. When all other effects of Wolbachia on the mosquito physiology are ignored, cytoplasmic incompatibility alone results in a reduction in the number of human dengue cases. A sensitivity analysis of the parameters in the model shows that the transmission probability, the biting rate and the average adult mosquito death rate are the most important parameters for the outcome of the cumulative proportion of human individuals infected with dengue.
Project description:Comparison of insecticide resistant mosquitoes (An. arabiensis) with control samples, comparison of resistant samples with susceptible (Dongola) strain and comparison of resistant (Sennar) strain with susceptible (Dongola) strain
Project description:We conducted a whole transcriptome analysis of testes from a meiotic drive-carrying strain (T37) in comparison with a drive-sensitive strain (RED) using microarrays based on the complete annotated Ae. aegypti gene set. The T37 strain, which carries a strong meiotic drive gene (Mori et al., 2004 (PMID 15605641)), was established from mosquitoes collected in Trinidad. The RED strain is highly sensitive to the meiotic drive gene (Hickey and Craig, 1966 (PMID ); Mori et al., 2004 (PMID 15605641)).
Project description:Oral susceptibility of Aedes aegypti mosquitoes to dengue viruses varies between different Aedes species and strains. However, the midgut-specific transcriptional profile that may produce this variation is presently obscure and was the subject of our investigation. The variation in active expression between dengue-2 susceptible (SUS) and refractory (REF) mosquitoes was investigated during the first critical 96 hours after infection Transcriptional profiles were mined from respective guts using the serial analysis of gene expression technique (SAGE) and libraries constructed from midguts obtained from mosquitoes that received a dengue-2 infected blood meal (DENV-2), a non infected blood meal (naive) or a 5% sucrose meal (SM). Here we report that variation between DENV-2 infected libraries versus respective naïve libraries revealed very few transcripts that were common and statistically significant in DENV-2 infected libraries. In addition, the expression profiles among libraries displayed up regulation of antisense transcripts especially in the SUS strain. A strong proclivity towards strain-specificity in differential expression was observed, which suggested an exclusive transcription that is likely up-regulated after DENV-2 infection