ABSTRACT: Blood feeding is an integral process of the malaria vector Anopheles required for its physiological functions and its propagation. During blood feeding, presence of the malaria parasite, Plasmodium in the blood induces several host effector molecules including microRNAs which play important roles in the development and maturation of the parasite within the mosquito. The present study was undertaken to elucidate the dynamic expression of miRNAs during gonotrophic cycle and parasite development in Anopheles stephensi.For this purpose, miRNA microarray was done in sugar fed, 42 hours post blood fed and 42 hours post infected blood fed female mosquitoes to identify regulated miRNAs under these conditions.
Project description:Blood feeding is an integral process of the malaria vector Anopheles required for its physiological functions and its propagation. During blood feeding, presence of the malaria parasite, Plasmodium in the blood induces several host effector molecules including microRNAs which play important roles in the development and maturation of the parasite within the mosquito. The present study was undertaken to elucidate the dynamic expression of miRNAs during gonotrophic cycle and parasite development in Anopheles stephensi.For this purpose, small RNA sequencing was done in sugar fed, 42 hours and 5 days post blood fed and infected blood fed female mosquitoes to identify regulated miRNAs under these conditions.
Project description:Salivary gland proteins of Anopheles mosquitoes offer attractive targets to understand interactions with sporozoites, blood feeding behavior, homeostasis and immunological evaluation of malaria vectors and parasite interactions. To date limited studies have been carried out to elucidate salivary proteins of An. stephensi salivary glands. The aim of the present study was to provide detailed analytical attributives of functional salivary gland proteins of urban malaria vector An. stephensi. A proteomic approach combining one-dimensional electrophoresis (1DE), ion trap liquid chromatography mass spectrometry (LC/MS/MS) and computational bioinformatic analysis was adopted to provide the first direct insight into identification and functional characterization of known salivary proteins and novel salivary proteins of An. stephensi. Computational studies by online servers namely, Mascot and OMSSA algorithms identified a total of 36 known salivary proteins and 123 novel proteins analysed by LC/MS/MS. This first report describes a baseline proteomic catalogue of 159 salivary proteins belonging to various categories of signal transduction, regulation of blood coagulation cascade, and various immune and energy pathways of An. stephensi sialo-transcriptome by mass spectrometry. Our results may serve as basis to provide a putative functional role of proteins into concept of blood feeding, biting behavior and other aspects of vector-parasite host interactions for parasite development in anopheline mosquitoes.
Project description:Background: The Anopheles gambiae salivary glands play a major role in malaria transmission and express a variety of bioactive components that facilitate blood-feeding by preventing platelet aggregation, blood clotting, vasodilatation, and inflammatory and other reactions at the probing site on the vertebrate host. Results: We have performed a global transcriptome analysis of the A. gambiae salivary gland response to blood-feeding, to identify candidate genes that are involved in hematophagy. A total of 4,978 genes were found to be transcribed in this tissue. A comparison of salivary gland transcriptomes prior to and after blood-feeding identified 52 and 41 transcripts that were significantly up-regulated and down-regulated, respectively. Ten genes were further selected to assess their role in the blood-feeding process using RNAi-mediated gene silencing methodology. Depletion of the salivary gland genes encoding D7L2, anophelin, peroxidase, the SG2 precursor, and a 5'nucleotidase gene significantly increased probing time of A. gambiae mosquitoes and thereby their capacity to blood-feed. Conclusions: The salivary gland transcriptome comprises approximately 38% of the total mosquito transcriptome and a small proportion of it is dynamically changing already at two hours in response to blood feeding. A better understanding of the salivary gland transcriptome and its function can contribute to the development of pathogen transmission control strategies and the identification of medically relevant bioactive compounds. Salivary glands from blood-fed vs. unfed A. gambiae. 3 replicates.
Project description:Background: Anopheles culicifacies is a rural vector of malaria in tropical and sub tropical South East Asian region. The salivary gland of the mosquito is the target for sporozoite interaction, blood feeding behavior, haemostasis and vector-parasite interactions. Malaria parasite matures inside the salivary gland, gain competence and transmitted to the host along with the saliva during biting. The importance of the proteins expressed in salivary gland is the first step in understanding the physiology of blood feeding and may provide insights into vector- parasite interactions. Since, no genomic or transcriptomics information is available of Anopheles culicifacies, therefore locally expressed functional proteins in salivary glands are of much importance. . Method: In this study, 1DE protein and in solution digestion was combined with tandem mass spectrometry (nano LC-MS/MS) and computational bioinformatics for data mining was employed to study the proteome profile of salivary glands of sugar fed An. culicifacies mosquito species. Functional annotation of all the identified proteins was carried out using gene ontology tools, CELLO and SMART analysis software. Results: Total 102 proteins were identified and analysed by SEQUEST algorithm against mosquito protein database from Uniprot/NCBI. Out of which 81 proteins were identified using gel free approach and 21 proteins using in-gel approach and 15 were common among these two approaches. All the identified proteins were categorized in to 23 groups of biological processes using GO tool. 7 proteins were depicted to be secretary in nature by investigating the signal peptide present. Potential proteins with unknown function were predicted by analyzing their functional association with other characterized proteins by STRING algorithm and were categorized in cell adhesion, cytoskeleton and membrane trafficking networks. Conclusion: Our study elucidates the first proteomic dataset of An. culicifacies salivary gland proteins. Functional annotation of salivary proteins and complementary gene ontology assignments in An. culicifacies species may contribute towards understanding the complex physiology of the tissues in this species. This proteome baseline data may facilitate the discernment of salivary glands and parasite correlation during blood feeding. Furthermore, this mass spectrometry based proteomic data may also provide insights into the elucidation of role of differential functional proteins present in refractory An. culicifacies mosquito and may be useful for development of effective malaria control strategies.
Project description:Senescence is a biological phenomenon experienced by all living eukaryote organisms. Genome-wide gene expression associated with aging has been explored in model organisms such as Drosophila melanogaster and Caenorhabditis elegans, but this has not been well understood in African malaria vector, Anopheles gambiae. Gene expression profiling using DNA microarray allows for simultaneous study of changes in mRNA levels for thousands of genes. This study examined genome-wide gene expression during aging process in An. gambiae. The influence of blood feeding on gene expression was also examined. The data can be used to further our understanding of mosquito senescence and identify biomarkers for mosquito age grading. Transcriptional profiles of Anopheles gambiae female mosquitoes were determined at 1, 4, 10, 19 and 28 days post adult eclosion. Additionally mosquitoes that had access to blood meals were compared to those that were maintained with access to only water and sugar.
Project description:The effect of chloroquine on mosquitoes transcript abundance was assayed by comparing gene expression between mosquitoes fed on a blood meal containing 50 mg/Kg of chloroquine and those that had fed on a normal blood meal. Pools of 50 midguts were dissected and were hybridize with MMC1 (or 20K) microarrays. <br><br>Anopheles gambiae female mosquitoes were blood fed on BALB/c mice infected with P. berghei and intraperitonally pre-treated with 50 mg/kg of chloroquine. As controls, mosquitoes were blood fed on untreated P. berghei infected mice.<br><br>Mosquitoes were collected 24 hours post-blood feeding and pools of 50 midguts were dissected and processed for hybridization with MMC1 (or 20K) microarrays.Two different biological experiments were performed for each treatment.
Project description:Mosquitoes possess an innate immune system that is capable of limiting infection by a variety of pathogens, including the Plasmodium spp. parasites responsible for human malaria. The Anopheles immune deficiency (IMD) innate immune signaling pathway confers resistance to Plasmodium falciparum. While some previously identified Anopheles anti-Plasmodium effectors are regulated through signaling by Rel2, the transcription factor of the IMD pathway, many components of this defense system remain uncharacterized. To begin to better understand the regulation of immune effector proteins by the IMD pathway, we used oligonucleotide microarrays and iTRAQ to analyze differences in mRNA and protein expression, respectively, between transgenic An. stephensi mosquitoes exhibiting blood meal-inducible overexpression of an active recombinant Rel2 and their wild-type conspecifics. Numerous genes were differentially regulated at both the mRNA and protein levels following induction of Rel2. While multiple immune genes were up-regulated, a majority of the differentially expressed genes have no known immune function in mosquitoes. Identified sequences were assigned putative functions and gene ontology (GO) terms based on homology to previously annotated A. gambiae gene sequences. Selected up-regulated genes from multiple GO categories were tested for both anti-Plasmodium and anti-bacterial action using RNA interference (RNAi). Based on our experimental findings, we conclude that increased expression of the IMD immune pathway-controlled transcription factor Rel2 affects the expression of numerous genes with diverse functions, suggesting a broader physiological impact of immune activation and possible functional versatility of Rel2. Our study has identified multiple novel anti-Plasmodium effectors. Midguts from midgut-specific transgenic A. stephensi at 6 and 12 hours post-blood meal and fat bodies from fat body-specific transgenic A. stephensi at 12 and 18 hours post-blood meal were compared to wild-type A. stephensi at the same time points. 3 biological replicates and 1 pseudo-replicate per array.
Project description:Overall, the study aims at obtaining a comprehensive picture of the African malaria mosquito, Anopheles gambiae, transcriptome using high-coverage RNA-seq of sexed whole-insect samples. This experiment focuses on transcriptomes of females subjected to physiological stress. The samples include adult females collected at different time intervals subject to sub-optimal relative humidity, after exposure to sublethal dose of deltamethrin, or following blood-feeding. Females kept at standard laboratory conditions without exposure to stressors, were collected at the same time intervals as control samples.
Project description:The mosquito Anopheles gambiae uses its innate immune system to control bacterial and Plasmodium infection of its midgut tissue. The activation of potent IMD pathway-mediated anti-Plasmodium falciparum defenses is dependent on the presence of the midgut microbiota, which activate this defense system upon parasite infection through a peptidoglycan recognition protein, PGRPLC. We employed transcriptomic and reverse genetic analyses to compare the P. falciparum infection-responsive transcriptomes of septic and aseptic mosquitoes and to determine whether bacteria-independent anti-Plasmodium defenses exist. To examine the impact of P. falciparum infection on the mosquito midgut and carcass transcriptomes in the presence or absence of midgut bacteria, we used A. gambiae whole genome microarrays to compare the mRNA abundance of P. falciparum-infected and -naïve mosquitoes of antibiotic- and non-antibiotic treated cohorts. P. falciparum infection induced changes in the abundance of as many as 2,183 and 2,429 transcripts in whole mosquitoes belonging to a variety of functional groups in aseptic and septic mosquitoes. Ultimately, we were interested in identifying the genes involved in bacteria-independent anti-Plasmodium responses, and therefore we focused on transcripts displaying increased abundance in the parasite-infected aseptic midguts, placing a particular emphasis on those with predicted immune functions. Because of the central role of serine protease cascades in regulating insect immune defenses, we focused the remainder of our analysis on a clip-domain serine protease C2 (CLIPC2, AGAP004317) and a serine protease inhibitor 7 (SRPN7, AGAP007693) that were specifically upregulated in the parasite-infected, aseptic mosquito midgut. We showed that SRPN7 negatively and CLIPC2 positively regulate the anti-Plasmodium defense, independently of the midgut-associated bacteria. Co-silencing assays suggested that these two genes may function together in a signaling cascade. Neither gene was regulated, nor modulated, by infection with the rodent malaria parasite Plasmodium berghei, suggesting that SRPN7 and CLIPC2 are components of a defense system with preferential activity towards P. falciparum. Further analysis using RNA interference determined that these genes do not regulate the anti-Plasmodium defense mediated by the IMD pathway, and both factors act as agonists of the endogenous midgut microbiota, further demonstrating the lack of functional relatedness between these genes and the bacteria-dependent activation of the IMD pathway. This is the first study confirming the existence of a bacteria-independent, anti-P. falciparum defense. Aseptic and septic midguts and carcasses from P. falciparum-infected A. gambiae vs aseptic and septic midguts and carcasses from uninfected, blood-fed A. gambiae. 3 biological replicates and 1 pseudo-replicate per each array.
Project description:Many eukaryotic developmental and cell fate decisions are effected post-transcriptionally that mechanistically involve RNA binding proteins as regulators of translation of key mRNAs. In the unicellular eukaryote malaria parasite, Plasmodium, one of the most dramatic changes in cell morphology and function occurs during transmission between mosquito and human host. In the mosquito salivary glands, Plasmodium sporozoites are slender, motile and remain infectious for several weeks; only after transmission and liver cell invasion, does the parasite rapidly transform into a round, non-motile exo-erythrocytic form (EEF) that gives rise to thousands of infectious merozoites to be released into the blood stream. Here we demonstrate a Plasmodium homolog of the RNA binding protein, Pumilio, as a key regulator of the sporozoite to EEF transformation. In the absence of Pumilio-2 (Puf2) Plasmodium berghei sporozoites initiate early stage EEF development inside mosquito salivary glands with characteristic morphological changes; puf2- salivary gland sporozoites lose gliding motility, cell traversal ability and are less infective. Global expression profiling confirmed that transgenic parasites exhibit genome-wide transcriptional adaptations typical for Plasmodium intra-hepatic development. The data demonstrate that Puf2 is a key player in regulating developmental control, and imply that transformation of salivary gland-resident sporozoites into early liver stage parasites is regulated by a post-translational mechanism.