Mating and blood-feeding induce transcriptome changes in the spermathecae of the yellow fever mosquito Aedes aegypti

Abstract Aedes aegypti mosquitoes are the primary vectors of numerous viruses that impact human health. As manipulation of reproduction has been proposed to suppress mosquito populations, elucidation of biological processes that enable males and females to successfully reproduce is necessary. One essential process is female sperm storage in specialized structures called spermathecae. Aedes aegypti females typically mate once, requiring them to maintain sperm viably to fertilize eggs they lay over their lifetime. Spermathecal gene products are required for Drosophila sperm storage and sperm viability, and a spermathecal-derived heme peroxidase is required for long-term Anopheles gambiae fertility. Products of the Ae. aegypti spermathecae, and their response to mating, are largely unknown. Further, although female blood-feeding is essential for anautogenous mosquito reproduction, the transcriptional response to blood-ingestion remains undefined in any reproductive tissue. We conducted an RNAseq analysis of spermathecae from unfed virgins, mated only, and mated and blood-fed females at 6, 24, and 72 h post-mating and identified significant differentially expressed genes in each group at each timepoint. A blood-meal following mating induced a greater transcriptional response in the spermathecae than mating alone. This study provides the first view of elicited mRNA changes in the spermathecae by a blood-meal in mated females.

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On the use of inhibitors of 4-hydroxyphenylpyruvate dioxygenase as a vector-selective insecticide in the control of mosquitoes

10.1101/669747 ◽

2019 ◽

Author(s):

Marlon A. V. Ramirez ◽

Marcos Sterkel ◽

Ademir de Jesus Martins ◽

José Bento Pereira Lima ◽

Pedro L. Oliveira

Keyword(s):

Amino Acids ◽

Body Weight ◽

Aedes Aegypti ◽

Blood Meal ◽

Mosquito Control ◽

Blood Feeding ◽

Degradation Pathway ◽

Cross Resistance ◽

Single Meal ◽

Neurotoxic Insecticides

AbstractBlood-sucking insects incorporate many times their body weight of blood in a single meal. As proteins are the major component of vertebrate blood, its digestion in the gut of hematophagous insects generates extremely high concentrations of free amino acids. Previous reports showed that the tyrosine degradation pathway plays an essential role in adapting these animals to blood feeding. Inhibiting 4-hydroxyphenylpyruvate dioxygenase (HPPD), the rate-limiting step of tyrosine degradation, results in the death of insects after a blood meal. Therefore, it was suggested that compounds that block the catabolism of tyrosine could act selectively on blood-feeding insects. Here we have evaluated the toxicity against mosquitoes of three HPPD inhibitors currently used as herbicides and in human health. Among the compounds tested, nitisinone (NTBC) proved to be more potent than mesotrione (MES) and isoxaflutole (IFT) in Aedes aegypti. NTBC was lethal to Ae. aegypti in artificial feeding assays (LD50: 4.36 µM), as well as in topical application (LD50: 0.0033 nmol/mosquito). NTBC was also lethal to Ae. aegypti populations that were resistant to neurotoxic insecticides, and it was lethal to other mosquito species (Anopheles and Culex). Therefore, HPPD inhibitors, particularly NTBC, represent promising new drugs for mosquito control. Since they only affect blood-feeding organisms, they would represent a safer and more environmentally friendly alternative to conventional neurotoxic insecticides.Author SummaryThe control of mosquitoes has been pursued in the last decades by the use of neurotoxic insecticides to prevent the spreading of dengue, zika and malaria, among other diseases. However, the selection and propagation of different mechanisms of resistance hinder the success of these compounds. New methodologies are needed for their control. Hematophagous arthropods, including mosquitoes, ingest quantities of blood that represent many times their body weight in a single meal, releasing huge amounts of amino acids during digestion. Recent studies showed that inhibition of the tyrosine catabolism pathway could be a new selective target for vector control. Thus we tested three different inhibitors of the second enzyme in the tyrosine degradation pathway as tools for mosquito control. Results showed that Nitisinone (NTBC), an inhibitor used in medicine, was the most potent of them. NTBC was lethal to Aedes aegypti when it was administered together with the blood meal and when it was topically applied. It also caused the death of Anopheles aquasalis and Culex quinquefasciatus mosquitoes, as well as field-collected Aedes populations resistant to neurotoxic insecticides, indicating that there is no cross-resistance. We discuss the possible use of NTBC as a new insecticide.

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Hormone-dependent activation and repression of microRNAs by the ecdysone receptor in the dengue vector mosquito Aedes aegypti

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2102417118 ◽

2021 ◽

Vol 118 (26) ◽

pp. e2102417118

Author(s):

Ya-Zhou He ◽

Emre Aksoy ◽

Yike Ding ◽

Alexander S. Raikhel

Keyword(s):

Aedes Aegypti ◽

Mirna Expression ◽

Blood Meal ◽

Fat Body ◽

Blood Feeding ◽

Small Rna Sequencing ◽

Sequencing Analysis ◽

Ecdysone Receptor ◽

Egg Development ◽

Semialdehyde Dehydrogenase

Female mosquitoes transmit numerous devastating human diseases because they require vertebrate blood meal for egg development. MicroRNAs (miRNAs) play critical roles across multiple reproductive processes in female Aedes aegypti mosquitoes. However, how miRNAs are controlled to coordinate their activity with the demands of mosquito reproduction remains largely unknown. We report that the ecdysone receptor (EcR)–mediated 20-hydroxyecdysone (20E) signaling regulates miRNA expression in female mosquitoes. EcR RNA-interference silencing linked to small RNA-sequencing analysis reveals that EcR not only activates but also represses miRNA expression in the female mosquito fat body, a functional analog of the vertebrate liver. EcR directly represses the expression of clustered miR-275 and miR-305 before blood feeding when the 20E titer is low, whereas it activates their expression in response to the increased 20E titer after a blood meal. Furthermore, we find that SMRTER, an insect analog of the vertebrate nuclear receptor corepressors SMRT and N-CoR, interacts with EcR in a 20E-sensitive manner and is required for EcR-mediated repression of miRNA expression in Ae. aegypti mosquitoes. In addition, we demonstrate that miR-275 and miR-305 directly target glutamate semialdehyde dehydrogenase and AAEL009899, respectively, to facilitate egg development. This study reveals a mechanism for how miRNAs are controlled by the 20E signaling pathway to coordinate their activity with the demands of mosquito reproduction.

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Novel small molecule agonists of an Aedes aegypti neuropeptide Y receptor block mosquito biting behavior

10.1101/393793 ◽

2018 ◽

Cited By ~ 2

Author(s):

Laura B. Duvall ◽

Lavoisier Ramos-Espiritu ◽

Kyrollos E. Barsoum ◽

J. Fraser Glickman ◽

Leslie B. Vosshall

Keyword(s):

Aedes Aegypti ◽

Neuropeptide Y ◽

Small Molecule ◽

Blood Meal ◽

Disease Transmission ◽

Blood Feeding ◽

Behavioral Suppression ◽

Host Seeking ◽

Novel Approach ◽

Seeking Behavior

AbstractFemale Aedes aegypti mosquitoes bite humans to obtain a blood-meal to develop their eggs. Remarkably, strong attraction to humans is suppressed for several days after the blood-meal by an unknown mechanism. We investigated a role for neuropeptide Y (NPY)-related signaling in this long-term behavioral suppression, and discovered that drugs targeting human NPY receptors modulate mosquito host-seeking behavior. In a screen of all 49 predicted Ae. aegypti peptide receptors, we identified NPY-like receptor 7 (NPYLR7) as the sole target of these human drugs. To obtain small molecule agonists selective for NPYLR7, we carried out a high-throughput cell-based assay of 265,211 compounds, and isolated 6 highly selective NPYLR7 agonists that inhibit mosquito attraction to humans. NPYLR7 CRISPR-Cas9 null mutants are defective in behavioral suppression, and resistant to these drugs. Finally, we show that these drugs are capable of inhibiting biting and blood-feeding on a live host, suggesting a novel approach to control infectious disease transmission by controlling mosquito behavior.

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The impact of mating and sugar feeding on blood-feeding physiology and behavior in the arbovirus vector mosquito Aedes aegypti

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009815 ◽

2021 ◽

Vol 15 (9) ◽

pp. e0009815

Author(s):

Garrett P. League ◽

Ethan C. Degner ◽

Sylvie A. Pitcher ◽

Yassi Hafezi ◽

Erica Tennant ◽

...

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Egg Production ◽

Control Strategies ◽

Blood Feeding ◽

Female Behavior ◽

Sugar Feeding ◽

And Behavior ◽

The Impact ◽

Initial Blood

Background Aedes aegypti mosquitoes are globally distributed vectors of viruses that impact the health of hundreds of millions of people annually. Mating and blood feeding represent fundamental aspects of mosquito life history that carry important implications for vectorial capacity and for control strategies. Females transmit pathogens to vertebrate hosts and obtain essential nutrients for eggs during blood feeding. Further, because host-seeking Ae. aegypti females mate with males swarming near hosts, biological crosstalk between these behaviors could be important. Although mating influences nutritional intake in other insects, prior studies examining mating effects on mosquito blood feeding have yielded conflicting results. Methodology/Principal findings To resolve these discrepancies, we examined blood-feeding physiology and behavior in virgin and mated females and in virgins injected with male accessory gland extracts (MAG), which induce post-mating changes in female behavior. We controlled adult nutritional status prior to blood feeding by using water- and sugar-fed controls. Our data show that neither mating nor injection with MAG affect Ae. aegypti blood intake, digestion, or feeding avidity for an initial blood meal. However, sugar feeding, a common supplement in laboratory settings but relatively rare in nature, significantly affected all aspects of feeding and may have contributed to conflicting results among previous studies. Further, mating, MAG injection, and sugar intake induced declines in subsequent feedings after an initial blood meal, correlating with egg production and laying. Taking our evaluation to the field, virgin and mated mosquitoes collected in Colombia were equally likely to contain blood at the time of collection. Conclusions/Significance Mating, MAG, and sugar feeding impact a mosquito’s estimated ability to transmit pathogens through both direct and indirect effects on multiple aspects of mosquito biology. Our results highlight the need to consider natural mosquito ecology, including diet, when assessing their physiology and behavior in the laboratory.

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Blood meal source and mixed blood-feeding influence gut bacterial community composition in Aedes aegypti

Parasites & Vectors ◽

10.1186/s13071-021-04579-8 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Ephantus J. Muturi ◽

Teresia M. Njoroge ◽

Christopher Dunlap ◽

Carla E. Cáceres

Keyword(s):

Bacterial Community ◽

Aedes Aegypti ◽

Gut Microbiota ◽

Microbial Communities ◽

Blood Meal ◽

Host Species ◽

Bacterial Community Composition ◽

Blood Feeding ◽

Mixed Blood ◽

Blood Meals

Abstract Background The guts of blood-sucking insects host a community of bacteria that can shift dramatically in response to biotic and abiotic factors. Identifying the key factors structuring these microbial communities has important ecological and epidemiological implications. Methods We used the yellow fever mosquito, Aedes aegypti, to investigate the impact of mixed blood meals on gut microbiota of vector mosquitoes. Adult females were experimentally fed on sugar or blood from chicken, rabbit or a mixture of chicken and rabbit blood, and their gut microbiota were characterized using 16S rRNA gene amplification and MiSeq sequencing. Results The gut bacterial communities of mosquitoes fed on the three blood meal treatments clustered separately, suggesting that host species identity and mixed blood-feeding are key determinants of gut bacterial community composition in mosquitoes. Mixed blood meal had a synergistic effect on both operational taxonomic unit (OTU) richness and the Shannon diversity index, suggesting that mixed blood-feeding can offset the nutritional deficit of blood meals from certain host species. The microbial communities observed in this study were distinct from those identified from similarly fed Ae. aegypti from our previous study. Conclusions These findings demonstrate that vector host-feeding preferences can influence gut microbial composition and diversity, which could potentially impact pathogen acquisition and transmission by the vector. The results also demonstrate that different microenvironmental conditions within the laboratory may play an important role in structuring the microbial communities of independently reared mosquito colonies.

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A transcriptomic atlas of Aedes aegypti reveals detailed functional organization of major body parts and gut regional specializations in sugar-fed and blood-fed adult females

10.1101/2021.12.19.473372 ◽

2021 ◽

Author(s):

Bretta Hixson ◽

Xiao-Li Bing ◽

Xiaowei Yang ◽

Alessandro Bonfini ◽

Peter Nagy ◽

...

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Time Course ◽

Functional Organization ◽

Blood Feeding ◽

Malpighian Tubules ◽

Mosquito Vector ◽

Body Parts ◽

Posterior Midgut ◽

Blood Meal Digestion

Mosquito vectors transmit numerous pathogens, but large gaps remain in our understanding of their physiology. To facilitate future explorations of mosquito biology, with specific attention to the major vector Aedes aegypti, we have created Aegypti-Atlas (http://aegyptiatlas.buchonlab.com/), an online resource hosting RNAseq profiles of Ae. aegypti body parts (head, thorax, abdomen, gut, Malpighian tubules, and ovaries), gut regions (crop, proventriculus, anterior and posterior midgut, and hindgut), and a time course of blood meal digestion in the gut. Using Aegypti-Atlas, we provide new insights into the regionalization of gut function, blood feeding response, and immune defenses. We find that the anterior and posterior regions of the mosquito midgut possess clearly delineated digestive specializations which are preserved in the blood-fed state. Blood feeding initiates the sequential transcriptional induction and repression/depletion of multiple cohorts of peptidases throughout blood meal digestion. With respect to defense, immune signaling components, but not recognition or effector molecules, show enrichment in ovaries. Basal expression of antimicrobial peptides is dominated by two genes, holotricin and gambicin, that are expressed in the carcass and the digestive tissues, respectively, in a near mutually exclusive manner. In the midgut, gambicin and other immune effector genes are almost exclusively expressed in the anterior regions, while the posterior midgut exhibits the hallmarks of immune tolerance. Finally, in a cross-species comparison between the midguts of Ae. aegypti and Anopheles gambiae, we observe that regional digestive and immune specializations are closely conserved, indicating that our data may yield inferences that are broadly relevant to multiple mosquito vector species. We further demonstrate that the expression of orthologous genes is highly correlated, with the exception of a ‘species signature’ comprising a small number of highly/disparately expressed genes. With this work, we show the potential of Aegypti-Atlas to unlock a more complete understanding of mosquito biology.

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Development of Trypanosoma (Schizotrypanum) hedricki in Cimex brevis (Hemiptera: Cimicidae)

Canadian Journal of Zoology ◽

10.1139/z81-078 ◽

1981 ◽

Vol 59 (3) ◽

pp. 546-554 ◽

Cited By ~ 16

Author(s):

Susan M. Bower ◽

Patrick T. K. Woo

Keyword(s):

Aedes Aegypti ◽

Trypanosoma Cruzi ◽

Blood Meal ◽

Agar Medium ◽

Blood Feeding ◽

Oral Route ◽

Myotis Lucifugus ◽

Infected Blood ◽

Big Brown Bats ◽

Large Numbers

Trypanosoma hedricki Bower and Woo from the blood of big brown bats (Eptesicus fuscus (Palisot de Beauvois)) developed in Cimex brevis Usinger and Ueshima. Approximately 24 h after the infected blood meal, the majority of the flagellates were still present in the first ventriculus of the gut but had transformed into epimastigotes. These epimastigotes divided by longitudinal binary fission. Four days after the blood meal, a few flagellates had reached the rectum of bugs held at 25 °C. These transformed into long thin metatrypanosomes. Not all bugs could be infected with T. hedricki but by 12 days after feeding, bugs with trypanosomes usually contained large numbers of metatrypanosomes in the rectum. These metatrypanosomes were infective to big brown bats when inoculated via the intraperitoneal or oral route. Little brown bats (Myotis lucifugus (Le Conte)) could not be infected. The morphology of the vector forms was similar to that of forms cultured in diphasic blood agar medium at about 21 °C and to those of Trypanosoma cruzi Chagas reported from triatomine bugs.Trypanosoma hedricki would not develop in blood-feeding mites (Steatonyssus occidentalis (Ewing)), Rhodnius prolixus Stål, or Aedes aegypti (Linnaeus).

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METHODS OF MEASURING BLOOD MEAL SIZE AND PROTEINASE ACTIVITY FOR DETERMINING EFFECTS OF MATED STATE ON DIGESTIVE PROCESSES OF FEMALE AEDES AEGYPTI (L.) (DIPTERA: CULICIDAE)

The Canadian Entomologist ◽

10.4039/ent118241-3 ◽

1986 ◽

Vol 118 (3) ◽

pp. 241-248 ◽

Cited By ~ 10

Author(s):

Jon G. Houseman ◽

A.E.R. Downe

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Trichloroacetic Acid ◽

Acid Precipitation ◽

Blood Feeding ◽

Meal Size ◽

Proteinase Activity ◽

Protein Loss ◽

Blood Meal Size ◽

Digestive Processes

AbstractTwo techniques for measuring size of ingested blood meal and 5 methods of measuring proteinase activity in the midgut of Aedes aegypti are compared. Protein, measured after trichloroacetic acid precipitation, was found to be most suitable for determining blood meal size and loss of protein from the gut. Of 5 proteinase substrates tested (BAPNA (benzoyl-DL-arginine-p-nitroanilide), hemoglobin, casein, azocasein, and hide powder azure), BAPNA was considered most suitable for trypsin measurements. These techniques were used to show that virgin females, 6 and 10 days after eclosion, consumed smaller meals than mated females. Virgin females also showed delays in both onset of protein loss from the gut and the increase in proteinase activity after blood feeding.

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Heterogeneity of midgut cells and their differential responses to blood meal ingestion by the mosquito, Aedes aegypti

10.1101/2020.08.31.275941 ◽

2020 ◽

Author(s):

Yingjun Cui ◽

Alexander W.E. Franz

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Mosquito Species ◽

Cell Types ◽

Blood Feeding ◽

Nutrient Absorption ◽

Cell Type ◽

Blood Digestion ◽

Mosquito Midgut ◽

Meal Ingestion

AbstractMosquitoes are the most notorious hematophagous insects and due to their blood feeding behavior and genetic compatibility, numerous mosquito species are highly efficient vectors for certain human pathogenic parasites and viruses. The mosquito midgut is the principal organ of blood meal digestion and nutrient absorption. It is also the initial site of infection with blood meal acquired parasites and viruses. We conducted an analysis based on single-nucleus RNA sequencing (snRNA-Seq) to assess the cellular diversity of the midgut and how individual cells respond to blood meal ingestion to facilitate its digestion. Our study revealed the presence of 20 distinguishable cell-type clusters in the female midgut of Aedes aegypti. The identified cell types included intestinal stem cell (ISC), enteroblasts (EB), differentiating EB (dEB), enteroendocrine cells (EE), enterocytes (EC), EC-like cells, cardia cells, and visceral muscle (VM) cells. Blood meal ingestion dramatically changed the overall midgut cell type composition, profoundly increasing the proportions of ISC and three EC/EC like clusters. In addition, transcriptional profiles of all cell types were strongly affected while genes involved in various metabolic processes were significantly upregulated. Our study provides a basis for further physiological and molecular studies on blood digestion, nutrient absorption, and cellular homeostasis in the mosquito midgut.

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ECDYSONE-MEDIATED STIMULATION OF DOPA DECARBOXYLASE ACTIVITY AND ITS RELATIONSHIP TO OVARIAN DEVELOPMENT IN AEDES AEGYPTI

The Journal of Cell Biology ◽

10.1083/jcb.61.2.454 ◽

1974 ◽

Vol 61 (2) ◽

pp. 454-465 ◽

Cited By ~ 54

Author(s):

Dorothy A. Schlaeger ◽

Morton S. Fuchs ◽

Suk-Hee Kang

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Ovarian Development ◽

Blood Feeding ◽

Dopa Decarboxylase ◽

Decarboxylase Activity ◽

Molting Hormone ◽

Radioimmune Assay ◽

Juvenile Hormone Mimic ◽

Stimulation Of

Very little dopa decarboxylase activity is detectable in adult female mosquitoes Aedes aegypti which have not been allowed to engorge blood. However, when such females are injected with the molting hormone ß-ecdysone a marked stimulation of this enzyme's activity is observable. No stimulation is observed in males similarly injected, nor in females injected with cholesterol or a juvenile hormone mimic. In addition, ecdysone injection initiates ovarian development in these anautogenous non-blood-fed mosquitoes. The extent of stimulation in both cases is dependent upon the amount of ß-ecdysone administered. These results suggested that ecdysone may play a role in ovarian development in Aedes and led us to hypothesize that a normal blood meal may trigger the synthesis, activation, or release of this hormone endogenously. Using the radioimmune assay for ecdysone developed by Borst and O'Connor (Science [Wash. D. C.] 178:4–18.), we found that the titer of an antigenic-positive material, presumably ecdysone or a closely related analogue, substantially increased 24 h after blood feeding, thereby supporting our postulation.

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