Browsing by Subject "Vector"

Now showing 1 - 6 of 6
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    Applications of geospatial analysis techniques for public health
    (2016-05-02) Stanforth, Austin Curran; Filippelli, Gabriel; Johnson, Daniel P.; Wang, Lixin; Wilson, Jeffrey; Moreno-Madriñán, Max J.; Jacinthe, Pierre-André
    Geospatial analysis is a generic term describing several technologies or methods of computational analysis using the Earth as a living laboratory. These methods can be implemented to assess risk and study preventative mitigation practices for Public Health. Through the incorporation Geographic Information Science and Remote Sensing tools, data collection can be conducted at a larger scale, more frequent, and less expensive that traditional in situ methods. These techniques can be extrapolated to be used to study a variety of topics. Application of these tools and techniques were demonstrated through Public Health research. Although it is understand resolution, or scale, of a research project can impact a study’s results; further research is needed to understand the extent of the result’s bias. Extreme heat vulnerability analysis was studied to validate previously identified socioeconomic and environmental variables influential for mitigation studies, and how the variability of resolution impacts the results of the methodology. Heat was also investigated for the implication of spatial and temporal resolution, or aggregation, influence on results. Methods studying the physical and socioeconomic environments of Dengue Fever outbreaks were also studied to identify patters of vector emergence.
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    Characterization of an adulticidal and larvicidal interfering RNA pesticide that targets a conserved sequence in mosquito G protein-coupled dopamine 1 receptor genes
    (Elsevier, 2020) Hapairai, Limb K.; Mysore, Keshava; Sun, Longhua; Li, Ping; Wang, Chien-Wei; Scheel, Nicholas D.; Lesnik, Alexandra; Scheel, Max P.; Igiede, Jessica; Wei, Na; Severson, David W.; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
    G protein-coupled receptors (GPCRs), key regulators of a variety of critical biological processes, are attractive targets for insecticide development. Given the importance of these receptors in many organisms, including humans, it is critical that novel pesticides directed against GPCRs are designed to be species-specific. Here, we present characterization of an interfering RNA pesticide (IRP) targeting the mosquito GPCR-encoding dopamine 1 receptor (dop1) genes. A small interfering RNA corresponding to dop1 was identified in a screen for IRPs that kill Aedes aegypti during both the adult and larval stages. The 25 bp sequence targeted by this IRP is conserved in the dop1 genes of multiple mosquito species, but not in non-target organisms, indicating that it could function as a biorational mosquito insecticide. Aedes aegypti adults treated through microinjection or attractive toxic sugar bait delivery of small interfering RNA corresponding to the target site exhibited severe neural and behavioral defects and high levels of adult mortality. Likewise, A. aegypti larval consumption of dried inactivated yeast tablets prepared from a Saccharomyces cerevisiae strain engineered to express short hairpin RNA corresponding to the dop1 target site resulted in severe neural defects and larval mortality. Aedes albopictus and Anopheles gambiae adult and larval mortality was also observed following treatment with dop1 IRPs, which were not toxic to non-target arthropods. The results of this investigation indicate that dop1 IRPs can be used for species-specific targeting of dop1 GPCRs and may represent a new biorational strategy for control of both adult and larval mosquitoes.
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    Examination of the genetic basis for sexual dimorphism in the Aedes aegypti (dengue vector mosquito) pupal brain
    (BioMed Central, 2014-10-21) Tomchaney, Michael; Mysore, Keshava; Sun, Longhua; Li, Ping; Emrich, Scott J.; Severson, David W.; Duman-Scheel, Molly; Department of Medical and Molecular Genetics, IU School of Medicine
    BACKGROUND: Most animal species exhibit sexually dimorphic behaviors, many of which are linked to reproduction. A number of these behaviors, including blood feeding in female mosquitoes, contribute to the global spread of vector-borne illnesses. However, knowledge concerning the genetic basis of sexually dimorphic traits is limited in any organism, including mosquitoes, especially with respect to differences in the developing nervous system. METHODS: Custom microarrays were used to examine global differences in female vs. male gene expression in the developing pupal head of the dengue vector mosquito, Aedes aegypti. The spatial expression patterns of a subset of differentially expressed transcripts were examined in the developing female vs. male pupal brain through in situ hybridization experiments. Small interfering RNA (siRNA)-mediated knockdown studies were used to assess the putative role of Doublesex, a terminal component of the sex determination pathway, in the regulation of sex-specific gene expression observed in the developing pupal brain. RESULTS: Transcripts (2,527), many of which were linked to proteolysis, the proteasome, metabolism, catabolic, and biosynthetic processes, ion transport, cell growth, and proliferation, were found to be differentially expressed in A. aegypti female vs. male pupal heads. Analysis of the spatial expression patterns for a subset of dimorphically expressed genes in the pupal brain validated the data set and also facilitated the identification of brain regions with dimorphic gene expression. In many cases, dimorphic gene expression localized to the optic lobe. Sex-specific differences in gene expression were also detected in the antennal lobe and mushroom body. siRNA-mediated gene targeting experiments demonstrated that Doublesex, a transcription factor with consensus binding sites located adjacent to many dimorphically expressed transcripts that function in neural development, is required for regulation of sex-specific gene expression in the developing A. aegypti brain. CONCLUSIONS: These studies revealed sex-specific gene expression profiles in the developing A. aegypti pupal head and identified Doublesex as a key regulator of sexually dimorphic gene expression during mosquito neural development.
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    Minimal Essential Human Factor VIII Alterations Enhance Secretion and Gene Therapy Efficiency
    (Elsevier, 2020-10-22) Cao, Wenjing; Dong, Biao; Horling, Franziska; Firrman, Jenni A.; Lengler, Johannes; Klugmann, Matthias; de la Rosa, Maurus; Wu, Wenman; Wang, Qizhao; Wei, Hongying; Moore, Andrea R.; Roberts, Sean A.; Booth, Carmen J.; Hoellriegl, Werner; Li, Dong; Konkle, Barbara; Miao, Carol; Reipert, Birgit M.; Scheiflinger, Friedrich; Rottensteiner, Hanspeter; Xiao, Weidong; Pediatrics, School of Medicine
    One important limitation for achieving therapeutic expression of human factor VIII (FVIII) in hemophilia A gene therapy is inefficient secretion of the FVIII protein. Substitution of five amino acids in the A1 domain of human FVIII with the corresponding porcine FVIII residues generated a secretion-enhanced human FVIII variant termed B-domain-deleted (BDD)-FVIII-X5 that resulted in 8-fold higher FVIII activity levels in the supernatant of an in vitro cell-based assay system than seen with unmodified human BDD-FVIII. Analysis of purified recombinant BDD-FVIII-X5 and BDD-FVIII revealed similar specific activities for both proteins, indicating that the effect of the X5 alteration is confined to increased FVIII secretion. Intravenous delivery in FVIII-deficient mice of liver-targeted adeno-associated virus (AAV) vectors designed to express BDD-FVIII-X5 or BDD-FVIII achieved substantially higher plasma FVIII activity levels for BDD-FVIII-X5, even when highly efficient codon-optimized F8 nucleotide sequences were employed. A comprehensive immunogenicity assessment using in vitro stimulation assays and various in vivo preclinical models of hemophilia A demonstrated that the BDD-FVIII-X5 variant does not exhibit an increased immunogenicity risk compared to BDD-FVIII. In conclusion, BDD-FVIII-X5 is an effective FVIII variant molecule that can be further developed for use in gene- and protein-based therapeutics for patients with hemophilia A.
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    Preparation and Use of a Yeast shRNA Delivery System for Gene Silencing in Mosquito Larvae
    (Humana Press, 2019) Mysore, Keshava; Hapairai, Limb K.; Wei, Na; Realey, Jacob S.; Scheel, Nicholas D.; Severson, David W.; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
    The mosquito genome projects facilitated research in new facets of mosquito biology, including functional genetic studies in the dengue and Zika virus vector Aedes aegypti and the primary African malaria vector Anopheles gambiae. RNA interference (RNAi) has facilitated gene silencing experiments in both of these disease vector mosquito species and could one day be applied as a new method of vector control. Here, we describe a procedure for the genetic engineering of Saccharomyces cerevisiae (baker’s yeast) that express short hairpin RNA (shRNA) corresponding to mosquito target genes of interest. Following cultivation, which facilitates inexpensive propagation of shRNA, the yeast is inactivated and prepared in a ready-to-use dry tablet formulation that is fed to mosquito larvae. Ingestion of the yeast tablets results in effective larval target gene silencing. This technically straightforward and affordable technique may be applicable to a wide variety of mosquito species and potentially to other arthropods that feed on yeast.
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    Yeast interfering RNA larvicides targeting neural genes induce high rates of Anopheles larval mortality
    (BioMed Central, 2017-11-13) Mysore, Keshava; Hapairai, Limb K.; Sun, Longhua; Harper, Elizabeth I.; Chen, Yingying; Eggleson, Kathleen K.; Realey, Jacob S.; Scheel, Nicholas D.; Severson, David W.; Wei, Na; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
    Background Although larviciding can reduce the number of outdoor biting malaria vector mosquitoes, which may help to prevent residual malaria transmission, the current larvicide repertoire is faced with great challenges to sustainability. The identification of new effective, economical, and biorational larvicides could facilitate maintenance and expansion of the practice of larviciding in integrated malaria vector mosquito control programmes. Interfering RNA molecules represent a novel class of larvicides with untapped potential for sustainable mosquito control. This investigation tested the hypothesis that short interfering RNA molecules can be used as mosquito larvicides. Results A small interfering RNA (siRNA) screen for larval lethal genes identified siRNAs corresponding to the Anopheles gambiae suppressor of actin (Sac1), leukocyte receptor complex member (lrc), and offtrack (otk) genes. Saccharomyces cerevisiae (baker’s yeast) was engineered to produce short hairpin RNAs (shRNAs) for silencing of these genes. Feeding larvae with the engineered yeasts resulted in silenced target gene expression, a severe loss of neural synapses in the larval brain, and high levels of larval mortality. The larvicidal activities of yeast interfering RNA larvicides were retained following heat inactivation and drying of the yeast into user-friendly tablet formulations that induced up to 100% larval mortality in laboratory trials. Conclusions Ready-to-use dried inactivated yeast interfering RNA larvicide tablets may someday be an effective and inexpensive addition to malaria mosquito control programmes and a valuable, biorational tool for addressing residual malaria transmission. Electronic supplementary material The online version of this article (10.1186/s12936-017-2112-5) contains supplementary material, which is available to authorized users.