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Sample records for aegypti larval midgut

  1. Novel Histopathological and Molecular Effects of Natural Compound Pellitorine on Larval Midgut Epithelium and Anal Gills of Aedes aegypti

    PubMed Central

    Perumalsamy, Haribalan; Kim, Jun-Ran; Oh, Sang Mi; Jung, Je Won; Ahn, Young-Joon; Kwon, Hyung Wook

    2013-01-01

    The yellow fever mosquito, Aedes aegypti, is a vector for transmitting dengue fever and yellow fever. In this study, we assessed the histopathological and molecular effects of pellitorine, an isobutylamide alkaloid, on the third instar of Ae. aegypti larvae. At 5 mg/l concentration of pellitorine, the whole body of the treated larvae became dark in color, particularly damaged thorax and abdominal regions. Pellitorine was targeted mainly on midgut epithelium and anal gills, indicating variably dramatic degenerative responses of the midgut through a sequential epithelial disorganization. The anterior and posterior midgut was entirely necrosed, bearing only gut lumen residues inside the peritrophic membranes. Pellitorine caused comprehensive damage of anal gill cells and branches of tracheole and debris was found in hemolymph of the anal gills. RT-PCR analysis indicates that the compound inhibited gene expression encoding V-type H+-ATPase and aquaporine 4 after treatment with 2.21 mg/l pellitorine. These results verify that pellitorine merits further study as a potential larvicide with a specific target site and a lead molecule for the control of mosquito populations. PMID:24260359

  2. THAP and ATF-2 Regulated Sterol Carrier Protein-2 Promoter Activities in the Larval Midgut of the Yellow Fever Mosquito, Aedes aegypti

    PubMed Central

    Peng, Rong; Fu, Qiang; Hong, Huazhu; Schwaegler, Tyler; Lan, Que

    2012-01-01

    Expression of sterol carrier protein-2 (SCP-2) in Aedes aegypti shows a distinct temporal/spatial pattern throughout the life cycle. In order to identify the transcription factors responsible for the larval temporal/spatial regulation of AeSCP-2 transcription, AeSCP-2 promoter activities were studied in vivo via transient transfection of promoter/reporter gene assays. Regulatory sequences upstream −1.3 kb of the transcription start site of AeSCP-2 were found to be critical for the in vivo temporal/spatial promoter activity. Interestingly, the −1.6 kb promoter sequence efficiently drove the larval midgut-specific siRNA expression, indicating that the −1.6 kb upstream sequence is sufficient for temporal/spatial AeSCP-2 transcriptional activity. Four transcription factors were identified in the midgut nuclear extract from feeding larvae via labeled −1.6/−1.3 kb DNA probe pull-down and proteomic analysis. Co-transfection of the promoter/reporter gene with inducible siRNA expression of each transcription factor was performed to confirm the regulatory function of individual transcription factor on AeSCP-2 transcriptional activities in the larval midgut. The results indicate that two of the identified transcription factors, Thanatos-associated protein (THAP) and activating transcription factor-2 (ATF-2), antagonistically control AeSCP-2 transcriptional activity in the midgut of feeding larvae via the regulatory sequences between −1.6 to −1.3 kb 5′ upstream of the transcription start site. In vivo expression knockdown of THAP and ATF-2 resulted in significant changes in developmental progression, which may be partially due to their effects on AeSCP-2 expression. PMID:23056538

  3. THAP and ATF-2 regulated sterol carrier protein-2 promoter activities in the larval midgut of the yellow fever mosquito, Aedes aegypti.

    PubMed

    Peng, Rong; Fu, Qiang; Hong, Huazhu; Schwaegler, Tyler; Lan, Que

    2012-01-01

    Expression of sterol carrier protein-2 (SCP-2) in Aedes aegypti shows a distinct temporal/spatial pattern throughout the life cycle. In order to identify the transcription factors responsible for the larval temporal/spatial regulation of AeSCP-2 transcription, AeSCP-2 promoter activities were studied in vivo via transient transfection of promoter/reporter gene assays. Regulatory sequences upstream -1.3 kb of the transcription start site of AeSCP-2 were found to be critical for the in vivo temporal/spatial promoter activity. Interestingly, the -1.6 kb promoter sequence efficiently drove the larval midgut-specific siRNA expression, indicating that the -1.6 kb upstream sequence is sufficient for temporal/spatial AeSCP-2 transcriptional activity. Four transcription factors were identified in the midgut nuclear extract from feeding larvae via labeled -1.6/-1.3 kb DNA probe pull-down and proteomic analysis. Co-transfection of the promoter/reporter gene with inducible siRNA expression of each transcription factor was performed to confirm the regulatory function of individual transcription factor on AeSCP-2 transcriptional activities in the larval midgut. The results indicate that two of the identified transcription factors, Thanatos-associated protein (THAP) and activating transcription factor-2 (ATF-2), antagonistically control AeSCP-2 transcriptional activity in the midgut of feeding larvae via the regulatory sequences between -1.6 to -1.3 kb 5' upstream of the transcription start site. In vivo expression knockdown of THAP and ATF-2 resulted in significant changes in developmental progression, which may be partially due to their effects on AeSCP-2 expression. PMID:23056538

  4. Comparative proteomic analysis of Aedes aegypti larval midgut after intoxication with Cry11Aa toxin from Bacillus thuringiensis.

    PubMed

    Cancino-Rodezno, Angeles; Lozano, Luis; Oppert, Cris; Castro, Julieta I; Lanz-Mendoza, Humberto; Encarnación, Sergio; Evans, Amy E; Gill, Sarjeet S; Soberón, Mario; Jurat-Fuentes, Juan L; Bravo, Alejandra

    2012-01-01

    Cry toxins produced by Bacillus thuringiensis bacteria are environmentally safe alternatives to control insect pests. They are pore-forming toxins that specifically affect cell permeability and cellular integrity of insect-midgut cells. In this work we analyzed the defensive response of Aedes aegypti larva to Cry11Aa toxin intoxication by proteomic and functional genomic analyses. Two dimensional differential in-gel electrophoresis (2D-DIGE) was utilized to analyze proteomic differences among A. aegypti larvae intoxicated with different doses of Cry11Aa toxin compared to a buffer treatment. Spots with significant differential expression (p<0.05) were then identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), revealing 18 up-regulated and seven down-regulated proteins. The most abundant subcategories of differentially expressed proteins were proteins involved in protein turnover and folding, energy production, and cytoskeleton maintenance. We selected three candidate proteins based on their differential expression as representatives of the different functional categories to perform gene silencing by RNA interference and analyze their functional role. The heat shock protein HSP90 was selected from the proteins involved in protein turnover and chaperones; actin, was selected as representative of the cytoskeleton protein group, and ATP synthase subunit beta was selected from the group of proteins involved in energy production. When we affected the expression of ATP synthase subunit beta and actin by silencing with RNAi the larvae became hypersensitive to toxin action. In addition, we found that mosquito larvae displayed a resistant phenotype when the heat shock protein was silenced. These results provide insight into the molecular components influencing the defense to Cry toxin intoxication and facilitate further studies on the roles of identified genes. PMID:22615881

  5. Additional morphological and physiological heterogeneity within the midgut of larval Aedes aegypti (Diptera: Culicidae) revealed by histology, electrophysiology, and effects of Bacillus thuringiensis endotoxin.

    PubMed

    Clark, T M; Hutchinson, M J; Huegel, K L; Moffett, S B; Moffett, D F

    2005-12-01

    Analysis of larval Aedes aegypti midgut using scanning electron microscopy, nuclear and mitochondrial dyes, response to Bacillus thuringiensis israelensis CryIVB toxin, and electrophysiology is described. The anterior ventriculus ("stomach") region is found to have much lower mitochondrial densities than other midgut regions. The transitional region is distinguished by apical surface architecture, and by region-specific effects of CryIVB endotoxin. In this region CryIVB causes holes ranging from 1.0 to 7.0 microm in diameter (mean 3.3+/-0.53 microm, N=12), blisters 16.9+/-1.54 microm in diameter (N=10), and separation of adjacent cells. The holes are not consistent with damage due to the colloid osmotic lysis model of delta-endotoxin activity. The posterior ventriculus possesses a distinctive cellular architecture consisting of hemispherical, domed apical membranes surrounded by deep clefts. Functional and morphological heterogeneity is revealed within the posterior ventriculus, with the anterior end dominating the electrical profile of isolated, perfused preparations and showing the greatest response to serotonin. Hyperpolarization of the transepithelial potential by serotonin occurred in conjunction with a decrease in the space constant lambda, ruling out closure of ion channels as the mechanism of action of serotonin.

  6. Schinus terebinthifolius Leaf Extract Causes Midgut Damage, Interfering with Survival and Development of Aedes aegypti Larvae.

    PubMed

    Procópio, Thamara Figueiredo; Fernandes, Kenner Morais; Pontual, Emmanuel Viana; Ximenes, Rafael Matos; de Oliveira, Aline Rafaella Cardoso; Souza, Carolina de Santana; Melo, Ana Maria Mendonça de Albuquerque; Navarro, Daniela Maria do Amaral Ferraz; Paiva, Patrícia Maria Guedes; Martins, Gustavo Ferreira; Napoleão, Thiago Henrique

    2015-01-01

    In this study, a leaf extract from Schinus terebinthifolius was evaluated for effects on survival, development, and midgut of A. aegypti fourth instar larvae (L4), as well as for toxic effect on Artemia salina. Leaf extract was obtained using 0.15 M NaCl and evaluated for phytochemical composition and lectin activity. Early L4 larvae were incubated with the extract (0.3-1.35%, w/v) for 8 days, in presence or absence of food. Polymeric proanthocyanidins, hydrolysable tannins, heterosid and aglycone flavonoids, cinnamic acid derivatives, traces of steroids, and lectin activity were detected in the extract, which killed the larvae at an LC50 of 0.62% (unfed larvae) and 1.03% (fed larvae). Further, the larvae incubated with the extract reacted by eliminating the gut content. No larvae reached the pupal stage in treatments at concentrations between 0.5% and 1.35%, while in the control (fed larvae), 61.7% of individuals emerged as adults. The extract (1.0%) promoted intense disorganization of larval midgut epithelium, including deformation and hypertrophy of cells, disruption of microvilli, and vacuolization of cytoplasms, affecting digestive, enteroendocrine, regenerative, and proliferating cells. In addition, cells with fragmented DNA were observed. Separation of extract components by solid phase extraction revealed that cinnamic acid derivatives and flavonoids are involved in larvicidal effect of the extract, being the first most efficient in a short time after larvae treatment. The lectin present in the extract was isolated, but did not show deleterious effects on larvae. The extract and cinnamic acid derivatives were toxic to A. salina nauplii, while the flavonoids showed low toxicity. S. terebinthifolius leaf extract caused damage to the midgut of A. aegypti larvae, interfering with survival and development. The larvicidal effect of the extract can be attributed to cinnamic acid derivatives and flavonoids. The data obtained using A. salina indicates that caution

  7. Schinus terebinthifolius Leaf Extract Causes Midgut Damage, Interfering with Survival and Development of Aedes aegypti Larvae

    PubMed Central

    Procópio, Thamara Figueiredo; Fernandes, Kenner Morais; Pontual, Emmanuel Viana; Ximenes, Rafael Matos; de Oliveira, Aline Rafaella Cardoso; Souza, Carolina de Santana; Melo, Ana Maria Mendonça de Albuquerque; Navarro, Daniela Maria do Amaral Ferraz; Paiva, Patrícia Maria Guedes; Martins, Gustavo Ferreira; Napoleão, Thiago Henrique

    2015-01-01

    In this study, a leaf extract from Schinus terebinthifolius was evaluated for effects on survival, development, and midgut of A. aegypti fourth instar larvae (L4), as well as for toxic effect on Artemia salina. Leaf extract was obtained using 0.15 M NaCl and evaluated for phytochemical composition and lectin activity. Early L4 larvae were incubated with the extract (0.3–1.35%, w/v) for 8 days, in presence or absence of food. Polymeric proanthocyanidins, hydrolysable tannins, heterosid and aglycone flavonoids, cinnamic acid derivatives, traces of steroids, and lectin activity were detected in the extract, which killed the larvae at an LC50 of 0.62% (unfed larvae) and 1.03% (fed larvae). Further, the larvae incubated with the extract reacted by eliminating the gut content. No larvae reached the pupal stage in treatments at concentrations between 0.5% and 1.35%, while in the control (fed larvae), 61.7% of individuals emerged as adults. The extract (1.0%) promoted intense disorganization of larval midgut epithelium, including deformation and hypertrophy of cells, disruption of microvilli, and vacuolization of cytoplasms, affecting digestive, enteroendocrine, regenerative, and proliferating cells. In addition, cells with fragmented DNA were observed. Separation of extract components by solid phase extraction revealed that cinnamic acid derivatives and flavonoids are involved in larvicidal effect of the extract, being the first most efficient in a short time after larvae treatment. The lectin present in the extract was isolated, but did not show deleterious effects on larvae. The extract and cinnamic acid derivatives were toxic to A. salina nauplii, while the flavonoids showed low toxicity. S. terebinthifolius leaf extract caused damage to the midgut of A. aegypti larvae, interfering with survival and development. The larvicidal effect of the extract can be attributed to cinnamic acid derivatives and flavonoids. The data obtained using A. salina indicates that caution

  8. The midgut of the silkmoth Bombyx mori is able to recycle molecules derived from degeneration of the larval midgut epithelium.

    PubMed

    Franzetti, Eleonora; Romanelli, Davide; Caccia, Silvia; Cappellozza, Silvia; Congiu, Terenzio; Rajagopalan, Muthukumaran; Grimaldi, Annalisa; de Eguileor, Magda; Casartelli, Morena; Tettamanti, Gianluca

    2015-08-01

    The midgut represents the middle part of the alimentary canal and is responsible for nutrient digestion and absorption in insect larva. Despite the growing interest in this organ for different purposes, such as studies on morphogenesis and differentiation, stem cell biology, cell death processes and transport mechanisms, basic information on midgut development is still lacking for a large proportion of insect species. Undoubtedly, this lack of data could hinder the full exploitation of practical applications that involve midgut as their primary target. This may represent in particular a significant problem for Lepidoptera, an insect order that includes some of the most important species of high economic importance. With the aim of overcoming this fragmentation of knowledge, we performed a detailed morphofunctional analysis of the midgut of the silkworm, Bombyx mori, a representative model among Lepidoptera, during its development from the larval up to the adult stage, focusing attention on stem cells. Our data demonstrate stem cell proliferation and differentiation, not only in the larval midgut but also in the pupal and adult midgut epithelium. Moreover, we present evidence for a complex trophic relationship between the dying larval epithelium and the new adult one, which is established during metamorphosis. This study, besides representing the first morphological and functional characterization of the changes that occur in the midgut of a lepidopteron during the transition from the larva to the moth, provides a detailed analysis of the midgut of the adult insect, a stage that has been neglected up to now.

  9. Larval midgut modifications associated with Bti resistance in the yellow fever mosquito using proteomic and transcriptomic approaches

    PubMed Central

    2012-01-01

    Background Bacillus thuringiensis var. israelensis (Bti) is a natural larval mosquito pathogen producing pore-forming toxins targeting the midgut of Diptera larvae. It is used worldwide for mosquito control. Resistance mechanisms of an Aedes aegypti laboratory strain selected for 30 generations with field-collected leaf litter containing Bti toxins were investigated in larval midguts at two levels: 1. gene transcription using DNA microarray and RT-qPCR and 2. differential expression of brush border membrane proteins using DIGE (Differential In Gel Electrophoresis). Results Several Bti Cry toxin receptors including alkaline phosphatases and N-aminopeptidases and toxin-binding V-ATPases exhibited altered expression levels in the resistant strain. The under-expression of putative Bti-receptors is consistent with Bt-resistance mechanisms previously described in Lepidoptera. Four soluble metalloproteinases were found under-transcribed together with a drastic decrease of metalloproteinases activity in the resistant strain, suggesting a role in resistance by decreasing the amount of activated Cry toxins in the larval midgut. Conclusions By combining transcriptomic and proteomic approaches, we detected expression changes at nearly each step of the ingestion-to-infection process, providing a short list of genes and proteins potentially involved in Bti-resistance whose implication needs to be validated. Collectively, these results open the way to further functional analyses to better characterize Bti-resistance mechanisms in mosquitoes. PMID:22703117

  10. Imidacloprid impairs the post-embryonic development of the midgut in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti).

    PubMed

    Fernandes, K M; Gonzaga, W G; Pascini, T V; Miranda, F R; Tomé, H V V; Serrão, J E; Martins, G F

    2015-09-01

    The mosquito Stegomyia aegypti (=Aedes aegypti) (Diptera: Culicidae) is a vector for the dengue and yellow fever viruses. As blood digestion occurs in the midgut, this organ constitutes the route of entry of many pathogens. The effects of the insecticide imidacloprid on the survival of St. aegypti were investigated and the sub-lethal effects of the insecticide on midgut development were determined. Third instar larvae were exposed to different concentrations of imidacloprid (0.15, 1.5, 3.0, 6.0 and 15.0 p.p.m.) and survival was monitored every 24 h for 10 days. Midguts from imidacloprid-treated insects at different stages of development were dissected and processed for analyses by transmission electron microscopy, immunofluorescence microscopy and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assays. Imidacloprid concentrations of 3.0 and 15.0 p.p.m. were found to affect midgut development similarly. Digestive cells of the fourth instar larvae (L4) midgut exposed to imidacloprid had more multilamellar bodies, abundantly found in the cell apex, and more electron-lucent vacuoles in the basal region compared with those from untreated insects. Moreover, imidacloprid interfered with the differentiation of regenerative cells, dramatically reducing the number of digestive and endocrine cells and leading to malformation of the midgut epithelium in adults. The data demonstrate that imidacloprid can reduce the survival of mosquitoes and thus indicate its potentially high efficacy in the control of St. aegypti populations.

  11. Whole-genome expression analysis in the third instar larval midgut of Drosophila melanogaster.

    PubMed

    Harrop, Thomas W R; Pearce, Stephen L; Daborn, Phillip J; Batterham, Philip

    2014-09-05

    Survival of insects on a substrate containing toxic substances such as plant secondary metabolites or insecticides is dependent on the metabolism or excretion of those xenobiotics. The primary sites of xenobiotic metabolism are the midgut, Malpighian tubules, and fat body. In general, gene expression in these organs is reported for the entire tissue by online databases, but several studies have shown that gene expression within the midgut is compartmentalized. Here, RNA sequencing is used to investigate whole-genome expression in subsections of third instar larval midguts of Drosophila melanogaster. The data support functional diversification in subsections of the midgut. Analysis of the expression of gene families that are implicated in the metabolism of xenobiotics suggests that metabolism may not be uniform along the midgut. These data provide a starting point for investigating gene expression and xenobiotic metabolism and other functions of the larval midgut.

  12. Whole-Genome Expression Analysis in the Third Instar Larval Midgut of Drosophila melanogaster

    PubMed Central

    Harrop, Thomas W. R.; Pearce, Stephen L.; Daborn, Phillip J.; Batterham, Philip

    2014-01-01

    Survival of insects on a substrate containing toxic substances such as plant secondary metabolites or insecticides is dependent on the metabolism or excretion of those xenobiotics. The primary sites of xenobiotic metabolism are the midgut, Malpighian tubules, and fat body. In general, gene expression in these organs is reported for the entire tissue by online databases, but several studies have shown that gene expression within the midgut is compartmentalized. Here, RNA sequencing is used to investigate whole-genome expression in subsections of third instar larval midguts of Drosophila melanogaster. The data support functional diversification in subsections of the midgut. Analysis of the expression of gene families that are implicated in the metabolism of xenobiotics suggests that metabolism may not be uniform along the midgut. These data provide a starting point for investigating gene expression and xenobiotic metabolism and other functions of the larval midgut. PMID:25193493

  13. Multiple Modes of Action of the Squamocin in the Midgut Cells of Aedes aegypti Larvae

    PubMed Central

    de Paula, Sérgio Oliveira; Martins, Gustavo Ferreira; Zanuncio, José Cola

    2016-01-01

    Annonaceous acetogenins are botanical compounds with good potential for use as insecticides. In the vector, Aedes aegypti (L.) (Diptera: Culicidae), squamocin (acetogenin) has been reported to be a larvicide and cytotoxic, but the modes of action of this molecule are still poorly understood. This study evaluated the changes in the cell morphology, and in the expression of genes, for autophagy (Atg1 and Atg8), for membrane ion transporter V-ATPase, and for water channel aquaporin-4 (Aqp4) in the midgut of A. aegypti larvae exposed to squamocin from Annona mucosa Jacq. (Annonaceae). Squamocin showed cytotoxic action with changes in the midgut epithelium and digestive cells of A. aegypti larvae, increase in the expression for autophagy gene Atg1 and Atg8, decrease in the expression of V-ATPase, decrease in the expression of Aqp4 gene in LC20 and inhibition of Apq4 genes in the midgut of this vector in LC50. These multiple modes of action for squamocin are described for the first time in insects, and they are important because different sites of action of squamocin from A. mucosa may reduce the possibility of resistance of A. aegypti to this molecule. PMID:27532504

  14. Multiple Modes of Action of the Squamocin in the Midgut Cells of Aedes aegypti Larvae.

    PubMed

    da Silva Costa, Marilza; de Paula, Sérgio Oliveira; Martins, Gustavo Ferreira; Zanuncio, José Cola; Santana, Antônio Euzébio Goulart; Serrão, José Eduardo

    2016-01-01

    Annonaceous acetogenins are botanical compounds with good potential for use as insecticides. In the vector, Aedes aegypti (L.) (Diptera: Culicidae), squamocin (acetogenin) has been reported to be a larvicide and cytotoxic, but the modes of action of this molecule are still poorly understood. This study evaluated the changes in the cell morphology, and in the expression of genes, for autophagy (Atg1 and Atg8), for membrane ion transporter V-ATPase, and for water channel aquaporin-4 (Aqp4) in the midgut of A. aegypti larvae exposed to squamocin from Annona mucosa Jacq. (Annonaceae). Squamocin showed cytotoxic action with changes in the midgut epithelium and digestive cells of A. aegypti larvae, increase in the expression for autophagy gene Atg1 and Atg8, decrease in the expression of V-ATPase, decrease in the expression of Aqp4 gene in LC20 and inhibition of Apq4 genes in the midgut of this vector in LC50. These multiple modes of action for squamocin are described for the first time in insects, and they are important because different sites of action of squamocin from A. mucosa may reduce the possibility of resistance of A. aegypti to this molecule. PMID:27532504

  15. Effects of proteinase inhibitor from Adenanthera pavonina seeds on short- and long term larval development of Aedes aegypti.

    PubMed

    Sasaki, Daniele Yumi; Jacobowski, Ana Cristina; de Souza, Antônio Pancrácio; Cardoso, Marlon Henrique; Franco, Octávio Luiz; Macedo, Maria Lígia Rodrigues

    2015-05-01

    Currently, one of the major global public health concerns is related to the transmission of dengue/yellow fever virus by the vector Aedes aegypti. The most abundant digestive enzymes in Ae. aegypti midgut larvae are trypsin and chymotrypsin. Since protease inhibitors have the capacity to bind to and inhibit the action of insect digestive proteinases, we investigated the short- and long-term effects of Adenanthera pavonina seed proteinase inhibitor (ApTI) on Ae. aegypti larvae, as well as a possible mechanism of adaptation. ApTI had a significant effect on Ae. aegypti larvae exposed to a non-lethal concentration of ApTI during short- and long-duration assays, decreasing survival, weight and proteinase activities of midgut extracts of larvae. The zymographic profile of ApTI demonstrated seven bands; three bands apparently have trypsin-like activity. Moreover, the peritrophic membrane was not disrupted. The enzymes of ApTI-fed larvae were found to be sensitive to ApTI and to have a normal feedback mechanism; also, the larval digestive enzymes were not able to degrade the inhibitor. In addition, ApTI delayed larval development time. Histological studies demonstrated a degeneration of the microvilli of the posterior midgut region epithelium cells, hypertrophy of the gastric caeca cells and an augmented ectoperitrophic space in larvae. Moreover, Ae. aegypti larvae were incapable of overcoming the negative effects of ApTI, indicating that this inhibitor might be used as a promising agent against Ae. aegypti. In addition, molecular modeling and molecular docking studies were also performed in order to construct three-dimensional theoretical models for ApTI, trypsin and chymotrypsin from Ae. aegypti, as well as to predict the possible interactions and affinity values for the complexes ApTI/trypsin and ApTI/chymotrypsin. In this context, this study broadens the base of our understanding about the modes of action of proteinase inhibitors in insects, as well as the way insects

  16. Effects of proteinase inhibitor from Adenanthera pavonina seeds on short- and long term larval development of Aedes aegypti.

    PubMed

    Sasaki, Daniele Yumi; Jacobowski, Ana Cristina; de Souza, Antônio Pancrácio; Cardoso, Marlon Henrique; Franco, Octávio Luiz; Macedo, Maria Lígia Rodrigues

    2015-05-01

    Currently, one of the major global public health concerns is related to the transmission of dengue/yellow fever virus by the vector Aedes aegypti. The most abundant digestive enzymes in Ae. aegypti midgut larvae are trypsin and chymotrypsin. Since protease inhibitors have the capacity to bind to and inhibit the action of insect digestive proteinases, we investigated the short- and long-term effects of Adenanthera pavonina seed proteinase inhibitor (ApTI) on Ae. aegypti larvae, as well as a possible mechanism of adaptation. ApTI had a significant effect on Ae. aegypti larvae exposed to a non-lethal concentration of ApTI during short- and long-duration assays, decreasing survival, weight and proteinase activities of midgut extracts of larvae. The zymographic profile of ApTI demonstrated seven bands; three bands apparently have trypsin-like activity. Moreover, the peritrophic membrane was not disrupted. The enzymes of ApTI-fed larvae were found to be sensitive to ApTI and to have a normal feedback mechanism; also, the larval digestive enzymes were not able to degrade the inhibitor. In addition, ApTI delayed larval development time. Histological studies demonstrated a degeneration of the microvilli of the posterior midgut region epithelium cells, hypertrophy of the gastric caeca cells and an augmented ectoperitrophic space in larvae. Moreover, Ae. aegypti larvae were incapable of overcoming the negative effects of ApTI, indicating that this inhibitor might be used as a promising agent against Ae. aegypti. In addition, molecular modeling and molecular docking studies were also performed in order to construct three-dimensional theoretical models for ApTI, trypsin and chymotrypsin from Ae. aegypti, as well as to predict the possible interactions and affinity values for the complexes ApTI/trypsin and ApTI/chymotrypsin. In this context, this study broadens the base of our understanding about the modes of action of proteinase inhibitors in insects, as well as the way insects

  17. Differential Protein Modulation in Midguts of Aedes aegypti Infected with Chikungunya and Dengue 2 Viruses

    PubMed Central

    Tchankouo-Nguetcheu, Stéphane; Khun, Huot; Pincet, Laurence; Roux, Pascal; Bahut, Muriel; Huerre, Michel; Guette, Catherine; Choumet, Valérie

    2010-01-01

    Background Arthropod borne virus infections cause several emerging and resurgent infectious diseases. Among the diseases caused by arboviruses, dengue and chikungunya are responsible for a high rate of severe human diseases worldwide. The midgut of mosquitoes is the first barrier for pathogen transmission and is a target organ where arboviruses must replicate prior to infecting other organs. A proteomic approach was undertaken to characterize the key virus/vector interactions and host protein modifications that happen in the midgut for viral transmission to eventually take place. Methodology and Principal Findings Using a proteomics differential approach with two-Dimensional Differential in-Gel Electrophoresis (2D-DIGE), we defined the protein modulations in the midgut of Aedes aegypti that were triggered seven days after an oral infection (7 DPI) with dengue 2 (DENV-2) and chikungunya (CHIKV) viruses. Gel profile comparisons showed that the level of 18 proteins was modulated by DENV-2 only and 12 proteins were modulated by CHIKV only. Twenty proteins were regulated by both viruses in either similar or different ways. Both viruses caused an increase of proteins involved in the generation of reactive oxygen species, energy production, and carbohydrate and lipid metabolism. Midgut infection by DENV-2 and CHIKV triggered an antioxidant response. CHIKV infection produced an increase of proteins involved in detoxification. Conclusion/Significance Our study constitutes the first analysis of the protein response of Aedes aegypti's midgut infected with viruses belonging to different families. It shows that the differentially regulated proteins in response to viral infection include structural, redox, regulatory proteins, and enzymes for several metabolic pathways. Some of these proteins like antioxidant are probably involved in cell protection. On the other hand, we propose that the modulation of other proteins like transferrin, hsp60 and alpha glucosidase, may favour

  18. Transcriptome of the gypsy moth (Lymantria dispar) larval midgut in response to infection by Bacillus thuringiensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcriptomic profiles of the lepidopteran insect pest Lymantria dispar (gypsy moth) were characterized in the larval midgut in response to infection by the biopesticide Bacillus thuringiensis kurstaki. RNA-Seq approaches were used to define a set of 49,613 assembled transcript sequences, of which...

  19. Alkalinization by chloride/bicarbonate pathway in larval mosquito midgut

    PubMed Central

    Boudko, Dmitri Y.; Moroz, Leonid L.; Harvey, William R.; Linser, Paul J.

    2001-01-01

    The midgut of mosquito larvae maintains a specific lumen alkalinization profile with large longitudinal gradients (pH ≈ 3 units⋅mm−1) in which an extremely alkaline (pH ≈ 11) anterior midgut lies between near-neutral posterior midgut and gastric cecum (pH 7–8). A plasma membrane H+ V-ATPase energizes this alkalinization but the ion carriers involved are unknown. Capillary zone electrophoresis of body samples with outlet conductivity detection showed a specific transepithelial distribution of chloride and bicarbonate/carbonate ions, with high concentrations of both anions in the midgut tissue: 68.3 ± 5.64 and 50.8 ± 4.21 mM, respectively. Chloride was higher in the hemolymph, 57.6 ± 7.84, than in the lumen, 3.51 ± 2.58, whereas bicarbonate was higher in the lumen, 58.1 ± 7.34, than the hemolymph, 3.96 ± 2.89. Time-lapse video assays of pH profiles in vivo revealed that ingestion of the carbonic anhydrase inhibitor acetazolamide and the ion exchange inhibitor DIDS (4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid), at 10−4 M eliminates lumen alkalinization. Basal application of these inhibitors in situ also reduced gradients recorded with self-referencing pH-sensitive microelectrodes near the basal membrane by ≈65% and 85% respectively. Self-referencing chloride-selective microelectrodes revealed a specific spatial profile of transepithelial chloride transport with an efflux maximum in anterior midgut. Both acetazolamide and DIDS reduced chloride effluxes. These data suggest that an H+ V-ATPase-energized anion exchange occurs across the apical membrane of the epithelial cells and implicate an electrophoretic Cl−/HCO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{_{3}^{-}}}\\end{equation*}\\end{document} exchanger and carbonic anhydrase as

  20. Molecular genetic analysis of midgut serine proteases in Aedes aegypti mosquitoes.

    PubMed

    Isoe, Jun; Rascón, Alberto A; Kunz, Susan; Miesfeld, Roger L

    2009-12-01

    Digestion of blood meal proteins by midgut proteases provides anautogenous mosquitoes with the nutrients required to complete the gonotrophic cycle. Inhibition of protein digestion in the midgut of blood feeding mosquitoes could therefore provide a strategy for population control. Based on recent reports indicating that the mechanism and regulation of protein digestion in blood fed female Aedes aegypti mosquitoes is more complex than previously thought, we used a robust RNAi knockdown method to investigate the role of four highly expressed midgut serine proteases in blood meal metabolism. We show by Western blotting that the early phase trypsin protein (AaET) is maximally expressed at 3 h post-blood meal (PBM), and that AaET is not required for the protein expression of three late phase serine proteases, AaLT (late trypsin), AaSPVI (5G1), and AaSPVII. Using the trypsin substrate analog BApNA to analyze in vitro enzyme activity in midgut extracts from single mosquitoes, we found that knockdown of AaSPVI expression caused a 77.6% decrease in late phase trypsin-like activity, whereas, knockdown of AaLT and AaSPVII expression had no significant effect on BApNA activity. In contrast, injection of AaLT, AaSPVI, and AaSPVII dsRNA inhibited degradation of endogenous serum albumin protein using an in vivo protease assay, as well as, significantly decreased egg production in both the first and second gonotrophic cycles (P < 0.001). These results demonstrate that AaLT, AaSPVI, and AaSPVII all contribute to blood protein digestion and oocyte maturation, even though AaSPVI is the only abundant midgut late phase serine protease that appears to function as a classic trypsin enzyme. PMID:19883761

  1. Fluid absorption in the isolated midgut of adult female yellow fever mosquitoes (Aedes aegypti).

    PubMed

    Onken, Horst; Moffett, David F

    2015-07-01

    The transepithelial voltage (Vte) and the volume of isolated posterior midguts of adult female yellow fever mosquitoes (Aedes aegypti) were monitored. In all experiments, the initial Vte after filling the midgut was lumen negative, but subsequently became lumen positive at a rate of approximately 1 mV min(-1). Simultaneously, the midgut volume decreased, indicating spontaneous fluid absorption. When the midguts were filled and bathed with mosquito saline, the average rate of fluid absorption was 36.5±3.0 nl min(-1) (N=4, ±s.e.m.). In the presence of theophylline (10 mmol l(-1)), Vte reached significantly higher lumen-positive values, but the rate of fluid absorption was not affected (N=6). In the presence of NaCN (5 mmol l(-1)), Vte remained close to 0 mV (N=4) and fluid absorption was reduced (14.4±1.3 nl min(-1), N=3, ±s.e.m.). When midguts were filled with buffered NaCl (154 mmol l(-1) plus 1 mmol l(-1) HEPES) and bathed in mosquito saline with theophylline, fluid absorption was augmented (50.0±5.8 nl min(-1), N=12, ±s.e.m.). Concanamycin A (10 µmol l(-1)), ouabain (1 mmol l(-1)), and acetazolamide (1 mmol l(-1)) affected Vte in different ways, but all reduced fluid absorption by 60-70% of the value before addition of the drugs.

  2. A GPI-anchored alkaline phosphatase is a functional midgut receptor of Cry11Aa toxin in Aedes aegypti larvae.

    PubMed

    Fernandez, Luisa E; Aimanova, Karlygash G; Gill, Sarjeet S; Bravo, Alejandra; Soberón, Mario

    2006-02-15

    A 65 kDa GPI (glycosylphosphatidyl-inositol)-anchored ALP (alkaline phosphatase) was characterized as a functional receptor of the Bacillus thuringiensis subsp. israelensis Cry11Aa toxin in Aedes aegypti midgut cells. Two (a 100 kDa and a 65 kDa) GPI-anchored proteins that bound Cry11Aa toxin were preferentially extracted after treatment of BBMV (brush boder membrane vesicles) from Ae. aegypti midgut epithelia with phospholipase C. The 65 kDa protein was further purified by toxin affinity chromatography. The 65 kDa protein showed ALP activity. The peptide-displaying phages (P1.BBMV and P8.BBMV) that bound to the 65 kDa GPI-ALP (GPI-anchored ALP) and competed with the Cry11Aa toxin to bind to BBMV were isolated by selecting BBMV-binding peptide-phages by biopanning. GPI-ALP was shown to be preferentially distributed in Ae. aegypti in the posterior part of the midgut and in the caeca, by using P1.BBMV binding to fixed midgut tissue sections to determine the location of GPI-ALP. Cry11Aa binds to the same regions of the midgut and competed with P1.BBMV and P8.BBMV to bind to BBMV. The importance of this interaction was demonstrated by the in vivo attenuation of Cry11Aa toxicity in the presence of these phages. Our results shows that GPI-ALP is an important receptor molecule involved in Cry11Aa interaction with midgut cells and toxicity to Ae. aegypti larvae.

  3. Histochemical analysis of the goblet cell matrix in the larval midgut of Manduca sexta

    SciTech Connect

    Schultz, T.W.; Lozano, G.; Cajina-Quezada, M.

    1981-01-01

    Experimental analyses were made to histochemically determine the composition of the goblet cell matrix material in the larval midgut of the tobacco hornworm, Manduca sexta. Techniques employed following fixation in Carnoy fluid were the periodic acid-Schiff reaction and the alcian blue stain at pH 1.0 and pH 2.5 and following methylation and subsequent saponification. The cumulative evidence suggests that the plug material is an acid mucosubstance.

  4. Alpha-galactosidases from the larval midgut of Tenebrio molitor (Coleoptera) and Spodoptera frugiperda (Lepidoptera).

    PubMed

    Grossmann, G A; Terra, W R

    2001-01-01

    There are three midgut alpha-galactosidases (TG1, TG2, TG3) from Tenebrio molitor larvae that are partially resolved by ion-exchange chromatography. The enzymes have approximately the same pH optimum (5.0), pl value (4.6) and Mr value (46000-49000) as determined by gel filtration or native electrophoresis run in polyacrylamide gels with different concentrations. Substrate specificities and functions were proposed for the major T. molitor midgut alpha-galactosidases (TG2 and TG3) based on chromatographic, carbodiimide inactivation, Tris inhibition, and on substrate competition data. Thus, TG2 would hydrolyse alpha-1,6-galactosaccharides, exemplified by raffinose, whereas TG3 would act on melibiose and apparently also on digalactosyldiglyceride, the most important compound in the thylacoid membranes of chloroplasts. Most galactoside digestion should occur in the lumen of the first two thirds of T. molitor larval midguts, since alpha-galactosidase activity predominates there. Spodoptera frugiperda larvae have three midgut alpha-galactosidases (SG1, SG2, SG3) partially resolved by ion-exchange chromatography. The enzymes have similar pH optimum (5.8), pl value (7.2) and Mr value (46000-52000), and at least the major alpha-galactosidase must have an active carboxyl group in the active site. Based on data similar to those described for T. molitor, SG1 and SG3 should hydrolyse melibiose and SG3 should digest raffinose and, perhaps, also digalactosyldiglyceride. The midgut distribution of alpha-galactosidase activity supports the proposal that alpha-galactosidase digestion occurs at the surface of anterior midgut cells in Spodoptera frugiperda larvae.

  5. Tissue-specific transcriptome profiling of Plutella xylostella third instar larval midgut.

    PubMed

    Xie, Wen; Lei, Yanyuan; Fu, Wei; Yang, Zhongxia; Zhu, Xun; Guo, Zhaojiang; Wu, Qingjun; Wang, Shaoli; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2012-01-01

    The larval midgut of diamondback moth, Plutella xylostella, is a dynamic tissue that interfaces with a diverse array of physiological and toxicological processes, including nutrient digestion and allocation, xenobiotic detoxification, innate and adaptive immune response, and pathogen defense. Despite its enormous agricultural importance, the genomic resources for P. xylostella are surprisingly scarce. In this study, a Bt resistant P. xylostella strain was subjected to the in-depth transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes in the P. xylostella larval midgut. Using Illumina deep sequencing, we obtained roughly 40 million reads containing approximately 3.6 gigabases of sequence data. De novo assembly generated 63,312 ESTs with an average read length of 416 bp, and approximately half of the P. xylostella sequences (45.4%, 28,768) showed similarity to the non-redundant database in GenBank with a cut-off E-value below 10(-5). Among them, 11,092 unigenes were assigned to one or multiple GO terms and 16,732 unigenes were assigned to 226 specific pathways. In-depth analysis identified genes putatively involved in insecticide resistance, nutrient digestion, and innate immune defense. Besides conventional detoxification enzymes and insecticide targets, novel genes, including 28 chymotrypsins and 53 ABC transporters, have been uncovered in the P. xylostella larval midgut transcriptome; which are potentially linked to the Bt toxicity and resistance. Furthermore, an unexpectedly high number of ESTs, including 46 serpins and 7 lysozymes, were predicted to be involved in the immune defense.As the first tissue-specific transcriptome analysis of P. xylostella, this study sheds light on the molecular understanding of insecticide resistance, especially Bt resistance in an agriculturally important insect pest, and lays the foundation for future functional genomics research. In addition, current

  6. Morphological changes in the midgut of Aedes aegypti L. (Diptera: Culicidae) larvae following exposure to an Annona coriacea (Magnoliales: Annonaceae) extract.

    PubMed

    Costa, M S; Pinheiro, D O; Serrão, J E; Pereira, M J B

    2012-08-01

    Bioinsecticides are important in the control of disease vectors, but data regarding their physiological effects on target insects are incomplete. This study describes morphological changes that occur in the midgut of third instar Aedes aegypti L. (Diptera: Culicidae) following treatment with a methanolic extract of Annona coriacea (Magnoliales: Annonaceae). Dissected midguts were subdivided into anterior and posterior regions and analyzed by light and scanning electron microscopy. Insects exposed to the extract displayed intense, destructive cytoplasmic vacuolization in columnar and regenerative midgut cells. The apical surfaces of columnar cells exhibited cytoplasmic protrusions oriented toward the lumen, suggesting that these cells could be involved in apocrine secretory processes and/or apoptosis. We report that A. coriacea extracts induced morphological alterations in the midgut of A. aegypti midgut larvae, supporting the use of plant extracts for control of the dengue vector.

  7. Localization of post-proline cleaving peptidases in Tenebrio molitor larval midgut.

    PubMed

    Goptar, Irina A; Filippova, Irina Yu; Lysogorskaya, Elena N; Oksenoit, Elena S; Vinokurov, Konstantin S; Zhuzhikov, Dmitry P; Bulushova, Natalja V; Zalunin, Igor A; Dunaevsky, Yakov E; Belozersky, Mikhail A; Oppert, Brenda; Elpidina, Elena N

    2008-03-01

    Two soluble post-proline cleaving peptidase activities, PPCP1 and PPCP2, were demonstrated in Tenebrio molitor larval midgut with the substrate benzyloxycarbonyl-L-alanyl-L-proline p-nitroanilide. Both activities were serine peptidases. PPCP1 was active in acidic buffers, with maximum activity at pH 5.3, and was located mainly in the more acidic anterior midgut lumen. The dynamics of PPCP1 activity and the total activity of soluble digestive peptidases in the course of food digestion were similar, suggesting that the enzyme participates in protein digestion. PPCP2 is a nondigestive soluble tissue enzyme evenly distributed along the midgut. An increase in the activity of PPCP2 was observed in buffers of pH 5.6-8.6 and was maximal at pH 7.4. The sensitivity of PPCP2 to inhibitors and the effect of pH are similar to prolyl oligopeptidases with a cysteine residue near the substrate binding site.

  8. CPB1 of Aedes aegypti interacts with DENV2 E protein and regulates intracellular viral accumulation and release from midgut cells.

    PubMed

    Tham, Hong-Wai; Balasubramaniam, Vinod R M T; Tejo, Bimo Ario; Ahmad, Hamdan; Hassan, Sharifah Syed

    2014-12-01

    Aedes aegypti is a principal vector responsible for the transmission of dengue viruses (DENV). To date, vector control remains the key option for dengue disease management. To develop new vector control strategies, a more comprehensive understanding of the biological interactions between DENV and Ae. aegypti is required. In this study, a cDNA library derived from the midgut of female adult Ae. aegypti was used in yeast two-hybrid (Y2H) screenings against DENV2 envelope (E) protein. Among the many interacting proteins identified, carboxypeptidase B1 (CPB1) was selected, and its biological interaction with E protein in Ae. aegypti primary midgut cells was further validated. Our double immunofluorescent assay showed that CPB1-E interaction occurred in the endoplasmic reticulum (ER) of the Ae. aegypti primary midgut cells. Overexpression of CPB1 in mosquito cells resulted in intracellular DENV2 genomic RNA or virus particle accumulation, with a lower amount of virus release. Therefore, we postulated that in Ae. aegypti midgut cells, CPB1 binds to the E protein deposited on the ER intraluminal membranes and inhibits DENV2 RNA encapsulation, thus inhibiting budding from the ER, and may interfere with immature virus transportation to the trans-Golgi network. PMID:25521592

  9. CPB1 of Aedes aegypti interacts with DENV2 E protein and regulates intracellular viral accumulation and release from midgut cells.

    PubMed

    Tham, Hong-Wai; Balasubramaniam, Vinod R M T; Tejo, Bimo Ario; Ahmad, Hamdan; Hassan, Sharifah Syed

    2014-12-16

    Aedes aegypti is a principal vector responsible for the transmission of dengue viruses (DENV). To date, vector control remains the key option for dengue disease management. To develop new vector control strategies, a more comprehensive understanding of the biological interactions between DENV and Ae. aegypti is required. In this study, a cDNA library derived from the midgut of female adult Ae. aegypti was used in yeast two-hybrid (Y2H) screenings against DENV2 envelope (E) protein. Among the many interacting proteins identified, carboxypeptidase B1 (CPB1) was selected, and its biological interaction with E protein in Ae. aegypti primary midgut cells was further validated. Our double immunofluorescent assay showed that CPB1-E interaction occurred in the endoplasmic reticulum (ER) of the Ae. aegypti primary midgut cells. Overexpression of CPB1 in mosquito cells resulted in intracellular DENV2 genomic RNA or virus particle accumulation, with a lower amount of virus release. Therefore, we postulated that in Ae. aegypti midgut cells, CPB1 binds to the E protein deposited on the ER intraluminal membranes and inhibits DENV2 RNA encapsulation, thus inhibiting budding from the ER, and may interfere with immature virus transportation to the trans-Golgi network.

  10. Transcriptome of the lymantria dispar (gypsy moth) larval midgut and its response to infection by bacillus thuringiensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcriptomic profiles of the serious lepidopteran insect pest Lymantria dispar (gypsy moth) were characterized in the larval midgut in response to infection by Bacillus thuringiensis kurstaki, a biopesticide commonly used for its control in nature. RNA-Seq approaches were used to define a set of ...

  11. Partial characterization of a lipase from gypsy moth (lymantria dispar L.) larval midgut.

    PubMed

    Mrdaković, Marija; Lazarević, Jelica; Perić-Mataruga, Vesna; Ilijin, Larisa; Vlahović, Milena

    2008-01-01

    Lipase activity of the gypsy moth (Lymantria dispar L.) was studied by the spectrophotometric method using crude homogenate of fifth-instar larval midgut tissues as the enzyme source and p-nitrophenyl caprylate (pNPC) as substrate. A Km value of 0.310 mM and a Vmax value of 1.479 U/mg prot. were obtained for this substrate. Among various p-nitrophenyl esters tested, maximum activity was obtained for p-nitrophenyl caprylate and p-nitrophenyl caprate. The enzyme was most active at alkaline pH, with maximum at pH 8.2. Decreased activity was detected after preincubation in buffers of pH below 7.0 and above 8.2. The enzyme was unstable at room temperature. The enzyme was Ca2+ independent. Its activity was inhibited by PMSF, Fe2+, Ag+ and Pb2+, while Fe3+ inhibited enzyme activity by about 40%.

  12. Transcriptome of the Lymantria dispar (Gypsy Moth) Larval Midgut in Response to Infection by Bacillus thuringiensis

    PubMed Central

    Sparks, Michael E.; Blackburn, Michael B.; Kuhar, Daniel; Gundersen-Rindal, Dawn E.

    2013-01-01

    Transcriptomic profiles of the serious lepidopteran insect pest Lymantria dispar (gypsy moth) were characterized in the larval midgut in response to infection by Bacillus thuringiensis kurstaki, a biopesticide commonly used for its control. RNA-Seq approaches were used to define a set of 49,613 assembled transcript sequences, of which 838, 1,248 and 3,305 were respectively partitioned into high-, mid- and low-quality tiers on the basis of homology information. Digital gene expression profiles suggested genes differentially expressed at 24 hours post infection, and qRT-PCR analyses were performed for verification. The differentially expressed genes primarily associated with digestive function, including α-amylase, lipase and carboxypeptidase; immune response, including C-type lectin 4; developmental genes such as arylphorin; as well as a variety of binding proteins: cellular retinoic acid binding protein (lipid-binding), insulin-related peptide binding protein (protein-binding) and ovary C/EBPg transcription factor (nucleic acid-binding). This is the first study conducted to specifically investigate gypsy moth response to a bacterial infection challenge using large-scale sequencing technologies, and the results highlight important genes that could be involved in biopesticide resistance development or could serve as targets for biologically-based control mechanisms of this insect pest. PMID:23658687

  13. Transcriptome of the Lymantria dispar (gypsy moth) larval midgut in response to infection by Bacillus thuringiensis.

    PubMed

    Sparks, Michael E; Blackburn, Michael B; Kuhar, Daniel; Gundersen-Rindal, Dawn E

    2013-01-01

    Transcriptomic profiles of the serious lepidopteran insect pest Lymantria dispar (gypsy moth) were characterized in the larval midgut in response to infection by Bacillus thuringiensis kurstaki, a biopesticide commonly used for its control. RNA-Seq approaches were used to define a set of 49,613 assembled transcript sequences, of which 838, 1,248 and 3,305 were respectively partitioned into high-, mid- and low-quality tiers on the basis of homology information. Digital gene expression profiles suggested genes differentially expressed at 24 hours post infection, and qRT-PCR analyses were performed for verification. The differentially expressed genes primarily associated with digestive function, including α-amylase, lipase and carboxypeptidase; immune response, including C-type lectin 4; developmental genes such as arylphorin; as well as a variety of binding proteins: cellular retinoic acid binding protein (lipid-binding), insulin-related peptide binding protein (protein-binding) and ovary C/EBPg transcription factor (nucleic acid-binding). This is the first study conducted to specifically investigate gypsy moth response to a bacterial infection challenge using large-scale sequencing technologies, and the results highlight important genes that could be involved in biopesticide resistance development or could serve as targets for biologically-based control mechanisms of this insect pest. PMID:23658687

  14. Transcriptome of the Lymantria dispar (gypsy moth) larval midgut in response to infection by Bacillus thuringiensis.

    PubMed

    Sparks, Michael E; Blackburn, Michael B; Kuhar, Daniel; Gundersen-Rindal, Dawn E

    2013-01-01

    Transcriptomic profiles of the serious lepidopteran insect pest Lymantria dispar (gypsy moth) were characterized in the larval midgut in response to infection by Bacillus thuringiensis kurstaki, a biopesticide commonly used for its control. RNA-Seq approaches were used to define a set of 49,613 assembled transcript sequences, of which 838, 1,248 and 3,305 were respectively partitioned into high-, mid- and low-quality tiers on the basis of homology information. Digital gene expression profiles suggested genes differentially expressed at 24 hours post infection, and qRT-PCR analyses were performed for verification. The differentially expressed genes primarily associated with digestive function, including α-amylase, lipase and carboxypeptidase; immune response, including C-type lectin 4; developmental genes such as arylphorin; as well as a variety of binding proteins: cellular retinoic acid binding protein (lipid-binding), insulin-related peptide binding protein (protein-binding) and ovary C/EBPg transcription factor (nucleic acid-binding). This is the first study conducted to specifically investigate gypsy moth response to a bacterial infection challenge using large-scale sequencing technologies, and the results highlight important genes that could be involved in biopesticide resistance development or could serve as targets for biologically-based control mechanisms of this insect pest.

  15. Phoxim-induced damages of Bombyx mori larval midgut and titanium dioxide nanoparticles protective role under phoxim-induced toxicity.

    PubMed

    Su, Junju; Li, Bing; Cheng, Shen; Zhu, Zhou; Sang, Xuezi; Gui, Suxin; Xie, Yi; Sun, Qingqing; Cheng, Zhe; Cheng, Jie; Hu, Rengping; Shen, Weide; Xia, Qingyou; Zhao, Ping; Hong, Fashui

    2014-12-01

    Phoxim (O,O-diethyl O-(alpha-cyanobenzylideneamino) phosphorothioate) is a powerful organophosphorus pesticide with high potential for Bombyx mori larvae of silkworm exposure. However, it is possible that during the phoxim metabolism, there is generation of reactive oxygen species (ROS) and phoxim may produce oxidative stress and neurotoxicity in an intoxicated silkworm. Titanium dioxide nanoparticles (TiO2 NPs) pretreatment has been demonstrated to increase antioxidant capacity and acetylcholinesterase (AChE) activity in organisms. This study was, therefore, undertaken to determine phoxim-induced oxidative stress and neurotoxicity to determine whether phoxim intoxication alters the antioxidant system and AChE activity in the B. mori larval midgut, and to determine whether TiO2 NPs pretreatment attenuates phoxim-induced toxicity. The findings suggested that phoxim exposure decreased survival of B. mori larvae, increased malondialdehyde (MDA), carbonyl and 8-OHdG levels, and ROS accumulation in the midgut. Furthermore, phoxim significantly decreased the activities of AChE, superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione-S-transferase (GST), and levels of ascorbic acid (AsA), reduced glutathione (GSH), and thiol in the midgut. TiO2 pretreatment, however, could increase AChE activity, and remove ROS via activating SOD, CAT, APX, GR, and GST, and accelerating AsA-GSH cycle, thus attenuated lipid, protein, and DNA peroxidation and improve B. mori larval survival under phoxim-induced toxicity. Moreover, this experimental system would help nanomaterials to be applied in the sericulture.

  16. Effect of Moringa oleifera flower extract on larval trypsin and acetylcholinesterase activities in Aedes aegypti.

    PubMed

    Pontual, Emmanuel Viana; Napoleão, Thiago Henrique; Dias de Assis, Caio Rodrigo; de Souza Bezerra, Ranilson; Xavier, Haroudo Satiro; Navarro, Daniela Maria do Amaral Ferraz; Coelho, Luana Cassandra Breitenbach Barroso; Paiva, Patrícia Maria Guedes

    2012-03-01

    Aedes aegypti control is crucial to reducing dengue fever. Aedes aegypti larvae have developed resistance to organophosporous insecticides and the use of natural larvicides may help manage larval resistance by increasing elements in insecticide rotation programs. Here, we report on larvicidal activity of Moringa oleifera flower extract against A. aegypti L(1), L(2), L(3), and L(4) as well as the effect of flower extract on gut trypsin and whole-larval acetylcholinesterase from L(4.) In addition, the heated flower extract was investigated for larvicidal activity against L(4) and effect on larval gut trypsin. Moringa oleifera flower extract contains a proteinaceous trypsin inhibitor (M. oleifera flower trypsin inhibitor, MoFTI), triterpene (β-amyrin), sterol (β-sitosterol) as well as flavonoids (kaempferol and quercetin). Larvicidal activity was detected against L(2), L(3), and L(4) (LC(50) of 1.72%, 1.67%, and 0.92%, respectively). Flower extract inhibited L(4) gut trypsin (MoFTI K(i) = 0.6 nM) and did not affect acetylcholinesterase activity. In vivo assay showed that gut trypsin activity from L(4) treated with M. oleifera flower extract decreased over time (0-1,440 min) and was strongly inhibited (98.6%) after 310 min incubation; acetylcholinesterase activity was not affected. Thermal treatment resulted in a loss of trypsin inhibitor and larvicidal activities, supporting the hypothesis that flower extract contains a proteinaceous trypsin inhibitor that may be responsible for the deleterious effects on larval mortality. PMID:22392801

  17. Food availability alters the effects of larval temperature on Aedes aegypti growth.

    PubMed

    Padmanabha, H; Bolker, B; Lord, C C; Rubio, C; Lounibos, L P

    2011-09-01

    Variation in temperature and food availability in larval habitats can influence the abundance, body size, and vector competence of the mosquito Aedes aegypti. Although increased temperature has energetic costs for growing larvae, how food resources influence the developmental response of this mosquito species to thermal conditions is unknown. We explored how rearing temperature and food affect allometric scaling between wing size and epidermal cell size in Ae. aegypti. Mosquitoes were reared at 22 and 28 degrees C across a gradient of field-collected detritus designed to simulate commonly observed natural larval food resources. Overall, reduced temperature and increased food level increased wing size, but only temperature affected cell size. Females fed the least food had the longest time to maturation, and their increases in wing size induced by cold temperature were associated with larger, rather than more, cells. By contrast, males fed the most food had the shortest time to maturation, and their increases in wing size induced by cold temperature were associated with more, rather than larger, cells. Therefore, food levels can alter the underlying physiological mechanisms generating temperature-size patterns in mosquitoes, suggesting that the control of development is sensitive to the combination of nutrient and thermal conditions, rather than each independently. Conditions prolonging development time may favor increased cell division over growth. We suggest that understanding the effects of climate change on Ae. aegypti vectorial capacity requires an improved knowledge of how water temperature interacts with limited food resources and competition in aquatic container habitats.

  18. The 3D structure and function of digestive cathepsin L-like proteinases of Tenebrio molitor larval midgut.

    PubMed

    Beton, Daniela; Guzzo, Cristiane R; Ribeiro, Alberto F; Farah, Chuck S; Terra, Walter R

    2012-09-01

    Cathepsin L-like proteinases (CAL) are major digestive proteinases in the beetle Tenebrio molitor. Procathepsin Ls 2 (pCAL2) and 3 (pCAL3) were expressed as recombinant proteins in Escherichia coli, purified and activated under acidic conditions. Immunoblot analyses of different T. molitor larval tissues demonstrated that a polyclonal antibody to pCAL3 recognized pCAL3 and cathepsin L 3 (CAL3) only in the anterior two-thirds of midgut tissue and midgut luminal contents of T. molitor larvae. Furthermore, immunocytolocalization data indicated that pCAL3 occurs in secretory vesicles and microvilli in anterior midgut. Therefore CAL3, like cathepsin L 2 (CAL2), is a digestive enzyme secreted by T. molitor anterior midgut. CAL3 hydrolyses Z-FR-MCA and Z-RR-MCA (typical cathepsin substrates), whereas CAL2 hydrolyses only Z-FR-MCA. Active site mutants (pCAL2C25S and pCAL3C26S) were constructed by replacing the catalytic cysteine with serine to prevent autocatalytic processing. Recombinant pCAL2 and pCAL3 mutants (pCAL2C25S and pCAL3C26S) were prepared, crystallized and their 3D structures determined at 1.85 and 2.1 Å, respectively. While the overall structure of these enzymes is similar to other members of the papain superfamily, structural differences in the S2 subsite explain their substrate specificities. The data also supported models for CAL trafficking to lysosomes and to secretory vesicles to be discharged into midgut contents.

  19. Septic tanks as larval habitats for the mosquitoes Aedes aegypti and Culex quinquefasciatus in Playa-Playita, Puerto Rico.

    PubMed

    Burke, R; Barrera, R; Lewis, M; Kluchinsky, T; Claborn, D

    2010-06-01

    Adult Aedes aegypti (Linnaeus) (Diptera: Culicidae) were previously recovered from emergence traps on septic tanks in southeastern Puerto Rico. In this study we quantified immature mosquito abundance and its relationship with structural variables of the septic tanks and chemical properties of the water containing raw sewage. A miniaturized floating funnel trap was used to sample 89 septic tanks for larvae in the Puerto Rican community of Playa-Playita. Aedes aegypti larvae were recovered from 18% of the sampled tanks (10.3 larvae per septic tank per day). Larval presence was positively associated with cracking of the septic tank walls and uncovered access ports. Larval abundance was positively associated with cracking of the septic tank walls and larger tank surface areas, and inversely associated with the total dissolved solids (TDS). Culex quinquefasciatus (Say) larvae were also recovered from 74% of the septic tanks (129.6 larvae per septic tank per day). Larval presence was negatively associated with TDS in the water and larval abundance was positively associated with cracking of the septic tank walls. A screened, plastic emergence trap was used to sample 93 septic tanks within the community for Ae. aegypti and Cx. quinquefasciatus adults. Aedes aegypti adults were recovered from 49% of the sampled tanks (8.7 adults per septic tank per day) and Cx. quinquefasciatus adults were recovered from 97% of the sampled tanks (155.5 adults per septic tank per day). Aedes aegypti adult presence was positively associated with cracking, uncapped openings and septic water pH. The Ae. aegypti adult counts were positively associated with cracking and inversely associated with TDS and conductivity. This study marks the first published record of the recovery of Ae. aegypti larvae from holding tanks containing raw sewage in the Caribbean region. Our study indicates that Ae. aegypti larvae are present in sewage water and that septic tanks have at least the potential to maintain

  20. Aedes aegypti larval indices and risk for dengue epidemics.

    PubMed

    Sanchez, Lizet; Vanlerberghe, Veerle; Alfonso, Lázara; Marquetti, Maria del Carmen; Guzman, Maria Guadalupe; Bisset, Juan; van der Stuyft, Patrick

    2006-05-01

    We assessed in a case-control study the test-validity of Aedes larval indices for the 2000 Havana outbreak. "Cases" were blocks where a dengue fever patient lived during the outbreak. "Controls" were randomly sampled blocks. Before, during, and after the epidemic, we calculated Breteau index (BI) and house index at the area, neighborhood, and block level. We constructed receiver operating characteristic (ROC) curves to determine their performance as predictors of dengue transmission. We observed a pronounced effect of the level of measurement. The BI(max) (maximum block BI in a radius of 100 m) at 2-month intervals had an area under the ROC curve of 71%. At a cutoff of 4.0, it significantly (odds ratio 6.00, p<0.05) predicted transmission with 78% sensitivity and 63% specificity. Analysis of BI at the local level, with human-defined boundaries, could be introduced in control programs to identify neighborhoods at high risk for dengue transmission.

  1. Transcriptome Analysis of Bombyx mori Larval Midgut during Persistent and Pathogenic Cytoplasmic Polyhedrosis Virus Infection

    PubMed Central

    Kolliopoulou, Anna; Van Nieuwerburgh, Filip; Stravopodis, Dimitrios J.; Deforce, Dieter; Swevers, Luc; Smagghe, Guy

    2015-01-01

    Many insects can be persistently infected with viruses but do not show any obvious adverse effects with respect to physiology, development or reproduction. Here, Bombyx mori strain Daizo, persistently infected with cytoplasmic polyhedrosis virus (BmCPV), was used to study the host’s transcriptional response after pathogenic infection with the same virus in midgut tissue of larvae persistently and pathogenically infected as 2nd and 4th instars. Next generation sequencing revealed that from 13,769 expressed genes, 167 were upregulated and 141 downregulated in both larval instars following pathogenic infection. Several genes that could possibly be involved in B. mori immune response against BmCPV or that may be induced by the virus in order to increase infectivity were identified, whereas classification of differentially expressed transcripts (confirmed by qRT-PCR) resulted in gene categories related to physical barriers, immune responses, proteolytic / metabolic enzymes, heat-shock proteins, hormonal signaling and uncharacterized proteins. Comparison of our data with the available literature (pathogenic infection of persistently vs. non-persistently infected larvae) unveiled various similarities of response in both cases, which suggests that pre-existing persistent infection does not affect in a major way the transcriptome response against pathogenic infection. To investigate the possible host’s RNAi response against BmCPV challenge, the differential expression of RNAi-related genes and the accumulation of viral small RNAs (vsRNAs) were studied. During pathogenic infection, siRNA-like traces like the 2-fold up-regulation of the core RNAi genes Ago-2 and Dcr-2 as well as a peak of 20 nt small RNAs were observed. Interestingly, vsRNAs of the same size were detected at lower rates in persistently infected larvae. Collectively, our data provide an initial assessment of the relative significance of persistent infection of silkworm larvae on the host response following

  2. A comparison of larval, ovitrap and MosquiTRAP surveillance for Aedes (Stegomyia) aegypti.

    PubMed

    Resende, Marcelo Carvalho de; Silva, Ivoneide Maria; Ellis, Brett R; Eiras, Álvaro Eduardo

    2013-12-01

    In Brazil, the entomological surveillance of Aedes (Stegomyia) aegypti is performed by government-mandated larval surveys. In this study, the sensitivities of an adult sticky trap and traditional surveillance methodologies were compared. The study was performed over a 12-week period in a residential neighbourhood of the municipality of Pedro Leopoldo, state of Minas Gerais, Brazil. An ovitrap and a MosquiTRAP were placed at opposite ends of each neighbourhood block (60 traps in total) and inspections were performed weekly. The study revealed significant correlations of moderate strength between the larval survey, ovitrap and MosquiTRAP measurements. A positive relationship was observed between temperature, adult capture measurements and egg collections, whereas precipitation and frequency of rainy days exhibited a negative relationship. PMID:24402144

  3. A comparison of larval, ovitrap and MosquiTRAP surveillance for Aedes (Stegomyia) aegypti

    PubMed Central

    de Resende, Marcelo Carvalho; Silva, Ivoneide Maria; Ellis, Brett R; Eiras, Álvaro Eduardo

    2013-01-01

    In Brazil, the entomological surveillance of Aedes (Stegomyia) aegypti is performed by government-mandated larval surveys. In this study, the sensitivities of an adult sticky trap and traditional surveillance methodologies were compared. The study was performed over a 12-week period in a residential neighbourhood of the municipality of Pedro Leopoldo, state of Minas Gerais, Brazil. An ovitrap and a MosquiTRAP were placed at opposite ends of each neighbourhood block (60 traps in total) and inspections were performed weekly. The study revealed significant correlations of moderate strength between the larval survey, ovitrap and MosquiTRAP measurements. A positive relationship was observed between temperature, adult capture measurements and egg collections, whereas precipitation and frequency of rainy days exhibited a negative relationship. PMID:24402144

  4. Temperature, Larval Diet, and Density Effects on Development Rate and Survival of Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Couret, Jannelle; Dotson, Ellen; Benedict, Mark Q.

    2014-01-01

    Many environmental factors, biotic and abiotic interact to influence organismal development. Given the importance of Aedes aegypti as a vector of human pathogens including dengue and yellow fever, understanding the impact of environmental factors such as temperature, resource availability, and intraspecific competition during development is critical for population control purposes. Despite known associations between developmental traits and factors of diet and density, temperature has been considered the primary driver of development rate and survival. To determine the relative importance of these critical factors, wide gradients of conditions must be considered. We hypothesize that 1) diet and density, as well as temperature influence the variation in development rate and survival, 2) that these factors interact, and this interaction is also necessary to understand variation in developmental traits. Temperature, diet, density, and their two-way interactions are significant factors in explaining development rate variation of the larval stages of Ae. aegypti mosquitoes. These factors as well as two and three-way interactions are significantly associated with the development rate from hatch to emergence. Temperature, but not diet or density, significantly impacted juvenile mortality. Development time was heteroskedastic with the highest variation occurring at the extremes of diet and density conditions. All three factors significantly impacted survival curves of experimental larvae that died during development. Complex interactions may contribute to variation in development rate. To better predict variation in development rate and survival in Ae. aegypti, factors of resource availability and intraspecific density must be considered in addition, but never to the exclusion of temperature. PMID:24498328

  5. Temperature, larval diet, and density effects on development rate and survival of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Couret, Jannelle; Dotson, Ellen; Benedict, Mark Q

    2014-01-01

    Many environmental factors, biotic and abiotic interact to influence organismal development. Given the importance of Aedes aegypti as a vector of human pathogens including dengue and yellow fever, understanding the impact of environmental factors such as temperature, resource availability, and intraspecific competition during development is critical for population control purposes. Despite known associations between developmental traits and factors of diet and density, temperature has been considered the primary driver of development rate and survival. To determine the relative importance of these critical factors, wide gradients of conditions must be considered. We hypothesize that 1) diet and density, as well as temperature influence the variation in development rate and survival, 2) that these factors interact, and this interaction is also necessary to understand variation in developmental traits. Temperature, diet, density, and their two-way interactions are significant factors in explaining development rate variation of the larval stages of Ae. aegypti mosquitoes. These factors as well as two and three-way interactions are significantly associated with the development rate from hatch to emergence. Temperature, but not diet or density, significantly impacted juvenile mortality. Development time was heteroskedastic with the highest variation occurring at the extremes of diet and density conditions. All three factors significantly impacted survival curves of experimental larvae that died during development. Complex interactions may contribute to variation in development rate. To better predict variation in development rate and survival in Ae. aegypti, factors of resource availability and intraspecific density must be considered in addition, but never to the exclusion of temperature.

  6. Census of the Bacterial Community of the Gypsy Moth Larval Midgut by Using Culturing and Culture-Independent Methods

    PubMed Central

    Broderick, Nichole A.; Raffa, Kenneth F.; Goodman, Robert M.; Handelsman, Jo

    2004-01-01

    Little is known about bacteria associated with Lepidoptera, the large group of mostly phytophagous insects comprising the moths and butterflies. We inventoried the larval midgut bacteria of a polyphagous foliivore, the gypsy moth (Lymantria dispar L.), whose gut is highly alkaline, by using traditional culturing and culture-independent methods. We also examined the effects of diet on microbial composition. Analysis of individual third-instar larvae revealed a high degree of similarity of microbial composition among insects fed on the same diet. DNA sequence analysis indicated that most of the PCR-amplified 16S rRNA genes belong to the γ-Proteobacteria and low G+C gram-positive divisions and that the cultured members represented more than half of the phylotypes identified. Less frequently detected taxa included members of the α-Proteobacterium, Actinobacterium, and Cytophaga/Flexibacter/Bacteroides divisions. The 16S rRNA gene sequences from 7 of the 15 cultured organisms and 8 of the 9 sequences identified by PCR amplification diverged from previously reported bacterial sequences. The microbial composition of midguts differed substantially among larvae feeding on a sterilized artificial diet, aspen, larch, white oak, or willow. 16S rRNA analysis of cultured isolates indicated that an Enterococcus species and culture-independent analysis indicated that an Entbacter sp. were both present in all larvae, regardless of the feeding substrate; the sequences of these two phylotypes varied less than 1% among individual insects. These results provide the first comprehensive description of the microbial diversity of a lepidopteran midgut and demonstrate that the plant species in the diet influences the composition of the gut bacterial community. PMID:14711655

  7. Variant vicilins from a resistant Vigna unguiculata lineage (IT81D-1053) accumulate inside Callosobruchus maculatus larval midgut epithelium.

    PubMed

    Oliveira, Gabriel B; Kunz, Daniele; Peres, Tanara V; Leal, Rodrigo B; Uchôa, Adriana F; Samuels, Richard I; Macedo, Maria Lígia R; Carlini, Célia R; Ribeiro, Alberto F; Grangeiro, Thalles B; Terra, Walter R; Xavier-Filho, José; Silva, Carlos P

    2014-02-01

    It has been demonstrated that variant vicilins are the main resistance factor of cowpea seeds (Vigna unguiculata) against attack by the cowpea beetle Callosobruchus maculatus. There is evidence that the toxic properties of these storage proteins may be related to their interaction with glycoproteins and other microvillar membrane constituents along the digestive tract of the larvae. New findings have shown that following interaction with the microvilli, the vicilins are absorbed across the intestinal epithelium and thus reach the internal environment of the larvae. In the present paper we studied the insecticidal activity of the variant vicilins purified from a resistant cowpea variety (IT81D-1053). Bioassays showed that the seeds of this genotype affected larval growth, causing developmental retardation and 100% mortality. By feeding C. maculatus larvae on susceptible and IT81D-1053 derived vicilins (FITC labelled or unlabelled), followed by fluorescence and immunogold cytolocalization, we were able to demonstrate that both susceptible and variant forms are internalized in the midgut cells and migrate inside vesicular structures from the apex to the basal portion of the enterocytes. However, when larvae were fed with the labelled vicilins for 24h and then returned to a control diet, the concentration of the variant form remained relatively high, suggesting that variant vicilins are not removed from the cells at the same rate as the non-variant vicilins. We suggest that the toxic effects of variant vicilins on midgut cells involve the binding of these proteins to the cell surface followed by internalization and interference with the normal physiology of the enterocytes, thereby affecting larval development in vivo.

  8. Variant vicilins from a resistant Vigna unguiculata lineage (IT81D-1053) accumulate inside Callosobruchus maculatus larval midgut epithelium.

    PubMed

    Oliveira, Gabriel B; Kunz, Daniele; Peres, Tanara V; Leal, Rodrigo B; Uchôa, Adriana F; Samuels, Richard I; Macedo, Maria Lígia R; Carlini, Célia R; Ribeiro, Alberto F; Grangeiro, Thalles B; Terra, Walter R; Xavier-Filho, José; Silva, Carlos P

    2014-02-01

    It has been demonstrated that variant vicilins are the main resistance factor of cowpea seeds (Vigna unguiculata) against attack by the cowpea beetle Callosobruchus maculatus. There is evidence that the toxic properties of these storage proteins may be related to their interaction with glycoproteins and other microvillar membrane constituents along the digestive tract of the larvae. New findings have shown that following interaction with the microvilli, the vicilins are absorbed across the intestinal epithelium and thus reach the internal environment of the larvae. In the present paper we studied the insecticidal activity of the variant vicilins purified from a resistant cowpea variety (IT81D-1053). Bioassays showed that the seeds of this genotype affected larval growth, causing developmental retardation and 100% mortality. By feeding C. maculatus larvae on susceptible and IT81D-1053 derived vicilins (FITC labelled or unlabelled), followed by fluorescence and immunogold cytolocalization, we were able to demonstrate that both susceptible and variant forms are internalized in the midgut cells and migrate inside vesicular structures from the apex to the basal portion of the enterocytes. However, when larvae were fed with the labelled vicilins for 24h and then returned to a control diet, the concentration of the variant form remained relatively high, suggesting that variant vicilins are not removed from the cells at the same rate as the non-variant vicilins. We suggest that the toxic effects of variant vicilins on midgut cells involve the binding of these proteins to the cell surface followed by internalization and interference with the normal physiology of the enterocytes, thereby affecting larval development in vivo. PMID:24220155

  9. Purification, characterization and molecular cloning of the major chitinase from Tenebrio molitor larval midgut.

    PubMed

    Genta, Fernando A; Blanes, Lucas; Cristofoletti, Plínio T; do Lago, Claudimir L; Terra, Walter R; Ferreira, Clélia

    2006-10-01

    Insect chitinases are involved in degradation of chitin from the exoskeleton cuticle or from midgut peritrophic membrane during molts. cDNAs coding for insect cuticular and gut chitinases were cloned, but only chitinases from moulting fluid were purified and characterized. In this study the major digestive chitinase from T. molitor midgut (TmChi) was purified to homogeneity, characterized and sequenced after cDNA cloning. TmChi is secreted by midgut epithelial cells, has a molecular weight of 44 kDa and is unstable in the presence of midgut proteinases. TmChi shows strong substrate inhibition when acting on umbelliferyl-derivatives of chitobio- and chitotriosaccharides, but has normal Michaelis kinetics with the N-acetylglucosamine derivative as substrate. TmChi has very low activity against colloidal chitin, but effectively converts oligosaccharides to shorter fragments. The best substrate for TmChi is chitopentaose, with highest k(cat)/K(M) value. Sequence analysis and chemical modification experiments showed that the TmChi active site contains carboxylic groups and a tryptophane, which are known to be important for catalysis in family 18 chitinases. Modification with p-hidroximercuribenzoate of a cysteine residue, which is exposed after substrate binding, leads to complete inactivation of the enzyme. TmChi mRNA encodes a signal peptide plus a protein with 37 kDa and high similarity with other insect chitinases from family 18. Surprisingly, this gene does not encode the C-terminal Ser-Thr-rich connector and chitin-binding domain normally present in chitinases. The special features of TmChi probably result from its adaptation to digest chitin-rich food without damaging the peritrophic membrane.

  10. Spatial and temporal dynamics of Aedes aegypti larval sites in Bello, Colombia.

    PubMed

    Arboleda, Sair; Jaramillo-O, Nicolás; Peterson, A Townsend

    2012-06-01

    Counts of immature stages of the mosquito Aedes aegypti have been used to calculate several entomological indices of dengue vector abundance. Some studies have concluded that these indices can be used as indicators of dengue epidemic risk, while other studies have failed to find a predictive relationship. Ecological niche models have been able to predict distributional patterns in space and time, not only of vectors, but also of the diseases that they transmit. In this study, we used Landsat 7 ETM+ images and two niche-modeling algorithms to estimate the local-landscape ecological niche and the dynamics of Ae. aegypti larval habitats in Bello, Colombia, and to evaluate their potential spatial and temporal distribution. Our models showed low omission error with high confidence levels: about 13.4% of the area presents conditions consistently suitable for breeding across the entire study period (2002-2008). The proportion of neighborhoods predicted to be suitable showed a positive association with dengue case rates, whereas the vector-focused Bretau index had no relationship to case rates. As a consequence, niche models appear to offer a superior option for predictive evaluation of dengue transmission risk and anticipating the potential for outbreaks. PMID:22548535

  11. Effects of neem oil (Azadirachta indica A. Juss) on the replacement of the midgut epithelium in the lacewing Ceraeochrysa claveri during larval-pupal metamorphosis.

    PubMed

    Scudeler, Elton Luiz; Padovani, Carlos Roberto; Santos, Daniela Carvalho Dos

    2014-06-01

    Larvae of the lacewing Ceraeochrysa claveri were fed on eggs of Diatraeasaccharalis treated with neem oil at concentrations of 0.5%, 1% and 2% throughout the larval period. Pupae obtained from treated larvae were used in the study at five days after the completion of cocoon spinning to investigate the effects of neem oil on the replacement of the midgut epithelium during the larval-pupal transition. We observed that the old larval epithelium was shed into the midgut lumen and transformed into the yellow body. Old cells from the yellow body were destroyed by apoptosis and autophagy and were not affected by neem oil. However, neem oil did affect the new pupal epithelium. Cells from treated pupae showed cellular injuries such as a loss of microvilli, cytoplasmic vacuolization, an increase of glycogen stores, deformation of the rough endoplasmic reticulum and dilation of the perinuclear space. Additionally, the neem oil treatment resulted in the release of cytoplasmic protrusions, rupture of the plasma membrane and leakage of cellular debris into the midgut lumen, characteristics of cell death by necrosis. The results indicate that neem oil ingestion affects the replacement of midgut epithelium, causing cytotoxic effects that can alter the organism's physiology due to extensive cellular injuries.

  12. Effects of neem oil (Azadirachta indica A. Juss) on the replacement of the midgut epithelium in the lacewing Ceraeochrysa claveri during larval-pupal metamorphosis.

    PubMed

    Scudeler, Elton Luiz; Padovani, Carlos Roberto; Santos, Daniela Carvalho Dos

    2014-06-01

    Larvae of the lacewing Ceraeochrysa claveri were fed on eggs of Diatraeasaccharalis treated with neem oil at concentrations of 0.5%, 1% and 2% throughout the larval period. Pupae obtained from treated larvae were used in the study at five days after the completion of cocoon spinning to investigate the effects of neem oil on the replacement of the midgut epithelium during the larval-pupal transition. We observed that the old larval epithelium was shed into the midgut lumen and transformed into the yellow body. Old cells from the yellow body were destroyed by apoptosis and autophagy and were not affected by neem oil. However, neem oil did affect the new pupal epithelium. Cells from treated pupae showed cellular injuries such as a loss of microvilli, cytoplasmic vacuolization, an increase of glycogen stores, deformation of the rough endoplasmic reticulum and dilation of the perinuclear space. Additionally, the neem oil treatment resulted in the release of cytoplasmic protrusions, rupture of the plasma membrane and leakage of cellular debris into the midgut lumen, characteristics of cell death by necrosis. The results indicate that neem oil ingestion affects the replacement of midgut epithelium, causing cytotoxic effects that can alter the organism's physiology due to extensive cellular injuries. PMID:24560939

  13. Fine-scale temperature fluctuation and modulation of Dirofilaria immitis larval development in Aedes aegypti

    PubMed Central

    Ledesma, Nicholas; Harrington, Laura

    2015-01-01

    We evaluated degree-day predictions of Dirofilaria immitis development (HDU) under constant and fluctuating temperature treatments of equal average daily temperature. Aedes aegypti mosquitoes were infected with D. immitis microfilariae and parasite development was recorded at set time points in dissected mosquitoes. Time to L3 development in Malpighian tubules and detection in mosquito heads was shorter for larvae experiencing a daily regime of 19±9°C than larvae at constant 19°C; larval development rate in Malpighian tubules was slower in fluctuating regimes maintained above the 14°C developmental threshold than larvae under constant temperatures. We showed that hourly temperature modeling more accurately predicted D. immitis development to infective L3 stage. Development time differed between fluctuating and constant temperature treatments spanning the 14°C development threshold, implicating a physiological basis for these discrepancies. We conclude that average daily temperature models underestimate L3 development—and consequently dog heartworm transmission risk—at colder temperatures, and spatio-temporal models of D. immitis transmission risk should use hourly temperature data when analyzing high daily temperature ranges spanning 14°C. PMID:25747489

  14. Fine-scale temperature fluctuation and modulation of Dirofilaria immitis larval development in Aedes aegypti.

    PubMed

    Ledesma, Nicholas; Harrington, Laura

    2015-04-15

    We evaluated degree-day predictions of Dirofilaria immitis development (HDU) under constant and fluctuating temperature treatments of equal average daily temperature. Aedes aegypti mosquitoes were infected with D. immitis microfilariae and parasite development was recorded at set time points in dissected mosquitoes. Time to L3 development in Malpighian tubules and detection in mosquito heads was shorter for larvae experiencing a daily regime of 19±9°C than larvae at constant 19°C; larval development rate in Malpighian tubules was slower in fluctuating regimes maintained above the 14°C developmental threshold than larvae under constant temperatures. We showed that hourly temperature modeling more accurately predicted D. immitis development to infective L3 stage. Development time differed between fluctuating and constant temperature treatments spanning the 14°C development threshold, implicating a physiological basis for these discrepancies. We conclude that average daily temperature models underestimate L3 development-and consequently dog heartworm transmission risk-at colder temperatures, and spatiotemporal models of D. immitis transmission risk should use hourly temperature data when analyzing high daily temperature ranges spanning 14°C.

  15. Replicate surveys of larval habitats of Aedes aegypti in relation to Dengue haemorrhagic fever in Bangkok, Thailand.

    PubMed

    Tonn, R J; Sheppard, P M; Macdonald, W W; Bang, Y H

    1969-01-01

    Dengue haemorrhagic fever in Bangkok and Thonburi occurs principally during the wet season. The mosquito vector is Aedes aegypti. A study was made of the larval habitats of A. aegypti in 14 localities, at three different times of the year, to determine whether there were fluctuations in the A. aegypti population, as measured by the number of occupied habitats, which could be correlated with the incidence of the infection.The habitats were classified into 6 categories and a single larva was collected for identification from each one that was occupied. The number and percentage of occupied habitats of each category per 100 houses were analysed to determine whether there were differences between localities and between times of the year. Almost all the comparisons between localities were highly significant. There was evidence of slight changes in the number of occupied habitats from time to time, the chief increase being between the cool and the warm seasons and the chief decrease from the wet to the cool season, but it seems unlikely that outbreaks of dengue haemorrhagic fever can be explained by increases in A. aegypti densities during the wet season.

  16. Identification of a polymorphic mucin-like gene expressed in the midgut of the mosquito, Aedes aegypti, using an integrated bulked segregant and differential display analysis.

    PubMed Central

    Morlais, I; Severson, D W

    2001-01-01

    The identification of putative differentially expressed genes within genome regions containing QTL determining susceptibility of the mosquito, Aedes aegypti, to the malarial parasite, Plasmodium gallinaceum, was investigated using an integrated, targeted approach based on bulked segregant and differential display analysis. A mosquito F2 population was obtained from pairwise matings between the parasite-susceptible RED strain and the resistant MOYO-R substrain. DNA from female carcasses was used to genotype individuals at RFLP markers of known chromosomal position around the major QTL (pgs 1). Midguts, dissected 48 hr after an infected blood meal, were used to prepare two RNA bulks, each representing one of the parental genotypes at the QTL interval. The RNA bulks were compared by differential display PCR. A mucin-like protein gene (AeIMUC1) was isolated and characterized. The gene maps within the pgs 1 QTL interval and is expressed in the adult female midgut. AeIMUC1 RNA abundance decreased with time after blood meal ingestion. No differential expression was observed between the two mosquito strains but three different alleles with inter- and intrastrain allelic polymorphisms including indels and SNPs were characterized. The AeIMUC1 gene chromosome location and allelic polymorphisms raise the possibility that the protein might be involved in parasite-mosquito interactions. PMID:11454761

  17. Control of larval and egg development in Aedes aegypti with RNA interference against juvenile hormone acid methyl transferase.

    PubMed

    Van Ekert, Evelien; Powell, Charles A; Shatters, Robert G; Borovsky, Dov

    2014-11-01

    RNA interference (RNAi) is a powerful approach for elucidating gene functions in a variety of organisms, including mosquitoes and many other insects. Little has been done, however, to harness this approach in order to control adult and larval mosquitoes. Juvenile hormone (JH) plays a pivotal role in the control of reproduction in adults and metamorphism in larval mosquitoes. This report describes an approach to control Aedes aegypti using RNAi against JH acid methyl transferase (AeaJHAMT), the ultimate enzyme in the biosynthetic pathway of JH III that converts JH acid III (JHA III) into JH III. In female A. aegypti that were injected or fed jmtA dsRNA targeting the AeaJHAMT gene (jmtA) transcript, egg development was inhibited in 50% of the treated females. In mosquito larvae that were fed transgenic Pichia pastoris cells expressing long hair pin (LHP) RNA, adult eclosion was delayed by 3 weeks causing high mortality. Northern blot analyses and qPCR studies show that jmtA dsRNA causes inhibition of jmtA transcript in adults and larvae, which is consistent with the observed inhibition of egg maturation and larval development. Taken together, these results suggest that jmtA LHP RNA expressed in heat inactivated genetically modified P. pastoris cells could be used to control mosquito populations in the marsh.

  18. Control of larval and egg development in Aedes aegypti with RNA interference against juvenile hormone acid methyl transferase.

    PubMed

    Van Ekert, Evelien; Powell, Charles A; Shatters, Robert G; Borovsky, Dov

    2014-11-01

    RNA interference (RNAi) is a powerful approach for elucidating gene functions in a variety of organisms, including mosquitoes and many other insects. Little has been done, however, to harness this approach in order to control adult and larval mosquitoes. Juvenile hormone (JH) plays a pivotal role in the control of reproduction in adults and metamorphism in larval mosquitoes. This report describes an approach to control Aedes aegypti using RNAi against JH acid methyl transferase (AeaJHAMT), the ultimate enzyme in the biosynthetic pathway of JH III that converts JH acid III (JHA III) into JH III. In female A. aegypti that were injected or fed jmtA dsRNA targeting the AeaJHAMT gene (jmtA) transcript, egg development was inhibited in 50% of the treated females. In mosquito larvae that were fed transgenic Pichia pastoris cells expressing long hair pin (LHP) RNA, adult eclosion was delayed by 3 weeks causing high mortality. Northern blot analyses and qPCR studies show that jmtA dsRNA causes inhibition of jmtA transcript in adults and larvae, which is consistent with the observed inhibition of egg maturation and larval development. Taken together, these results suggest that jmtA LHP RNA expressed in heat inactivated genetically modified P. pastoris cells could be used to control mosquito populations in the marsh. PMID:25111689

  19. Trypsin inhibitor from Moringa oleifera flowers interferes with survival and development of Aedes aegypti larvae and kills bacteria inhabitant of larvae midgut.

    PubMed

    Pontual, Emmanuel Viana; de Lima Santos, Nataly Diniz; de Moura, Maiara Celine; Coelho, Luana Cassandra Breitenbach Barroso; do Amaral Ferraz Navarro, Daniela Maria; Napoleão, Thiago Henrique; Paiva, Patrícia Maria Guedes

    2014-02-01

    Moringa oleifera flower extract, with trypsin inhibitor activity, is a larvicidal agent on Aedes aegypti. This work reports the isolation of trypsin inhibitor (M. oleifera flower trypsin inhibitor (MoFTI)) and its effect on A. aegypti egg hatching, viability of newly hatched larvae, survival of pupae, and growth of inhabitant bacteria from midgut of fourth-instar larvae (L4). MoFTI (K i, 2.4 μM), isolated by affinity chromatography on trypsin-agarose column, was an 18.2 kDa polypeptide on sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Flower extract (at concentrations of 8.5-17.0 mg/mL) reduced egg hatchability while MoFTI (0.05-0.5 mg/mL) did not affect the hatching rate. Mortality of newly hatched larvae ranged from 3.5 to 19.1 % in the presence of the extract (4.0-17.0 mg/mL) and was also promoted by MoFTI (LC50, 0.3 mg/mL). After 72 h, larvae incubated with extract at 13.0 and 17.0 mg/mL were at stages L2 and L1, respectively, while in control they reached L3 instar. In the presence of MoFTI, at all concentrations tested, the larvae did not pass the first instar. Flower extract and MoFTI did not interfere on pupae survival. The extract and MoFTI inhibited the growth of L4 gut bacteria (minimum inhibitory concentrations of 3.47 and 0.031 mg/mL, respectively) but only the inhibitor showed bactericide effect (minimum bactericidal concentration of 1.0 mg/mL). The findings reported herein indicate that MoFTI constitutes a larvicidal principle from M. oleifera flowers against A. aegypti newly hatched larvae and is an antibacterial agent active against the microbiota from L4 gut. PMID:24271154

  20. Two Leptinotarsa uridine diphosphate N-acetylglucosamine pyrophosphorylases are specialized for chitin synthesis in larval epidermal cuticle and midgut peritrophic matrix.

    PubMed

    Shi, Ji-Feng; Fu, Jia; Mu, Li-Li; Guo, Wen-Chao; Li, Guo-Qing

    2016-01-01

    Uridine diphosphate-N-acetylglucosamine-pyrophosphorylase (UAP) is involved in the biosynthesis of chitin, an essential component of the epidermal cuticle and midgut peritrophic matrix (PM) in insects. In the present paper, two putative LdUAP genes were cloned in Leptinotarsa decemlineata. In vivo bioassay revealed that 20-hydroxyecdysone (20E) and an ecdysteroid agonist halofenozide activated the expression of the two LdUAPs, whereas a decrease in 20E by RNA interference (RNAi) of an ecdysteroidogenesis gene LdSHD and a 20E signaling gene LdFTZ-F1 repressed the expression. Juvenile hormone (JH), a JH analog pyriproxyfen and an increase in JH by RNAi of an allatostatin gene LdAS-C downregulated LdUAP1 but upregulated LdUAP2, whereas a decrease in JH by silencing of a JH biosynthesis gene LdJHAMT had converse effects. Thus, expression of LdUAPs responded to both 20E and JH. Moreover, knockdown of LdUAP1 reduced chitin contents in whole larvae and integument samples, thinned tracheal taenidia, impaired larval-larval molt, larval-pupal ecdysis and adult emergence. In contrast, silencing of LdUAP2 significantly reduced foliage consumption, decreased chitin content in midgut samples, damaged PM, and retarded larval growth. The resulting larvae had lighter fresh weights, smaller body sizes and depleted fat body. As a result, the development was arrested. Combined knockdown of LdUAP1 and LdUAP2 caused an additive negative effect. Our data suggest that LdUAP1 and LdUAP2 have specialized functions in biosynthesizing chitin in the epidermal cuticle and PM respectively in L. decemlineata. PMID:26592348

  1. Transport of H(+), Na(+) and K(+) across the posterior midgut of blood-fed mosquitoes (Aedes aegypti).

    PubMed

    Pacey, Evan K; O'Donnell, Michael J

    2014-02-01

    Following ingestion of a blood meal, the adult female mosquito undergoes a massive diuresis during which Na(+), Cl(-) and water are secreted at high rates by the Malpighian tubules. In the hours following completion of diuresis, digestion of the K(+)-rich blood cells provides a source of energy as well as amino acids for proteins in the developing eggs. Although the transport of inorganic ions by the Malpighian tubules of blood-fed mosquitoes has been extensively characterized, relatively little is known of the epithelial transport mechanisms responsible for movement of Na(+), H(+), and K(+) across the posterior midgut. In this paper we have used the Scanning Ion-selective Electrode Technique (SIET) to measure the basal (unstimulated) rates of transport of K(+), Na(+) and H(+) across the isolated posterior midgut at intervals after the blood meal. We have also measured luminal concentrations of Na(+) and K(+) and the transepithelial electrical potential at the same time points and have calculated the electrochemical potentials for Na(+), K(+) and H(+) across the midgut. SIET measurements reveal absorption (lumen to bath) of Na(+) and H(+) and secretion of K(+) for the first 2h after blood-feeding. By 24h after the meal, absorption of Na(+) and H(+) remains active while there is an electrochemical gradient favouring absorption of K(+). Inhibition by ouabain and Ba(2+) suggest a role for the Na(+)/K(+)-ATPase and K(+) channels in absorption of Na(+) and K(+), respectively. Inhibition of H(+) absorption by acetazolamide implicates carbonic anhydrase in transepithelial H(+) transport.

  2. Water Use Practices Limit the Effectiveness of a Temephos-Based Aedes aegypti Larval Control Program in Northern Argentina

    PubMed Central

    Garelli, Fernando M.; Espinosa, Manuel O.; Weinberg, Diego; Trinelli, María A.; Gürtler, Ricardo E.

    2011-01-01

    Background A five-year citywide control program based on regular application of temephos significantly reduced Aedes aegypti larval indices but failed to maintain them below target levels in Clorinda, northern Argentina. Incomplete surveillance coverage and reduced residuality of temephos were held as the main putative causes limiting effectiveness of control actions. Methodology The duration of temephos residual effects in household-owned water-holding tanks (the most productive container type and main target for control) was estimated prospectively in two trials. Temephos was applied using spoons or inside perforated small zip-lock bags. Water samples from the study tanks (including positive and negative controls) were collected weekly and subjected to larval mortality bioassays. Water turnover was estimated quantitatively by adding sodium chloride to the study tanks and measuring its dilution 48 hs later. Principal Findings The median duration of residual effects of temephos applied using spoons (2.4 weeks) was significantly lower than with zip-lock bags (3.4 weeks), and widely heterogeneous between tanks. Generalized estimating equations models showed that bioassay larval mortality was strongly affected by water type and type of temephos application depending on water type. Water type and water turnover were highly significantly associated. Tanks filled with piped water had high turnover rates and short-lasting residual effects, whereas tanks filled with rain water showed the opposite pattern. On average, larval infestations reappeared nine weeks post-treatment and seven weeks after estimated loss of residuality. Conclusions Temephos residuality in the field was much shorter and more variable than expected. The main factor limiting temephos residuality was fast water turnover, caused by householders' practice of refilling tanks overnight to counteract the intermittence of the local water supply. Limited field residuality of temephos accounts in part for the

  3. Insecticidal potential of Ocimum canum plant extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus larval and adult mosquitoes (Diptera: Culicidae).

    PubMed

    Murugan, Jimmantiyur Madhappan; Ramkumar, Govindaraju; Shivakumar, Muthugoundar Subramanian

    2016-01-01

    Mosquitoes have developed resistance to various synthetic insecticides, making their control increasingly difficult. Insecticides of botanical origin may serve as suitable natural control. This study evaluates the toxic potential of Ocimum canum (Sims) leaf extract and powder against Anopheles stephensi (Liston), Aedes aegypti (Lin) and Culex quinquefasciatus (Say) larval and adult mosquitoes. Larval mortality was observed after 24 h recovery period and adult smoke toxicity observed for 40 min duration at 10 min interval. Methanol extract of O. canum showed highest larval mortality against the larvae of C. quinquefasciatus LC50 = 28.3225, LC90 = 44.1150; Ae. aegypti LC50 = 43.327, LC90 = 61.249; and An. stephensi LC50 = 30.2001, LC90 = 48.2866 ppm. The smoke toxicities were 93% mortality in C. quinquefasciatus, 74% in Ae. aegypti and 79% in An. stephensi adults, respectively, whereas 100% mortality was recorded in the commercial mosquito control. Our results suggest that O. canum leaf extract and powder are natural insecticide, and ideal eco friendly approach for mosquito control.

  4. Larval development of Aedes aegypti and Aedes albopictus in peri-urban brackish water and its implications for transmission of arboviral diseases.

    PubMed

    Ramasamy, Ranjan; Surendran, Sinnathamby N; Jude, Pavilupillai J; Dharshini, Sangaralingam; Vinobaba, Muthuladchumy

    2011-11-01

    Aedes aegypti (Linnaeus) and Aedes albopictus Skuse mosquitoes transmit serious human arboviral diseases including yellow fever, dengue and chikungunya in many tropical and sub-tropical countries. Females of the two species have adapted to undergo preimaginal development in natural or artificial collections of freshwater near human habitations and feed on human blood. While there is an effective vaccine against yellow fever, the control of dengue and chikungunya is mainly dependent on reducing freshwater preimaginal development habitats of the two vectors. We show here that Ae. aegypti and Ae. albopictus lay eggs and their larvae survive to emerge as adults in brackish water (water with <0.5 ppt or parts per thousand, 0.5-30 ppt and >30 ppt salt are termed fresh, brackish and saline respectively). Brackish water with salinity of 2 to 15 ppt in discarded plastic and glass containers, abandoned fishing boats and unused wells in coastal peri-urban environment were found to contain Ae. aegypti and Ae. albopictus larvae. Relatively high incidence of dengue in Jaffna city, Sri Lanka was observed in the vicinity of brackish water habitats containing Ae. aegypti larvae. These observations raise the possibility that brackish water-adapted Ae. aegypti and Ae. albopictus may play a hitherto unrecognized role in transmitting dengue, chikungunya and yellow fever in coastal urban areas. National and international health authorities therefore need to take the findings into consideration and extend their vector control efforts, which are presently focused on urban freshwater habitats, to include brackish water larval development habitats.

  5. Bacterial Exposure at the Larval Stage Induced Sexual Immune Dimorphism and Priming in Adult Aedes aegypti Mosquitoes

    PubMed Central

    Moreno-García, Miguel; Vargas, Valeria; Ramírez-Bello, Inci; Hernández-Martínez, Guadalupe; Lanz-Mendoza, Humberto

    2015-01-01

    Gender differences in the immune response of insects are driven by natural selection for females and sexual selection for males. These natural forces entail a multitude of extrinsic and intrinsic factors involved in a genotype-environment interaction that results in sex-biased expression of the genes shared by males and females. However, little is known about how an infection at a particular ontogenetic stage may influence later stages, or how it may impact sexual immune dimorphism. Using Aedes aegypti mosquitoes, the aim of the present study was to analyze the effect of a bacterial exposure at the larval stage on adult immunity in males and females. The parameters measured were phenoloxidase activity, nitric oxide production, antimicrobial activity, and the antimicrobial peptide transcript response. As a measure of the immune response success, the persistence of injected bacteria was also evaluated. The results show that males, as well as females, were able to enhance survival in the adult stage as a result of being exposed at the larval stage, which indicates a priming effect. Moreover, there was a differential gender immune response, evidenced by higher PO activity in males as well as higher NO production and greater antimicrobial activity in females. The greater bacterial persistence in females suggests a gender-specific strategy for protection after a previous experience with an elicitor. Hence, this study provides a primary characterization of the complex and gender-specific immune response of male and female adults against a bacterial challenge in mosquitoes primed at an early ontogenetic stage. PMID:26181517

  6. Effects of α,β-unsaturated lactones on larval survival and gut trypsin as well as oviposition response of Aedes aegypti.

    PubMed

    Barros, Maria Ester S B; Freitas, Juliano C R; Santos, Geanne K N; da Silva, Rayane Cristine Santos; Pontual, Emmanuel V; Paiva, Patrícia M G; Napoleão, Thiago H; Navarro, Daniela M A F; Menezes, Paulo H

    2015-09-01

    Lactones are organic cyclic esters that have been described as larvicides against Aedes aegypti and as components of oviposition pheromone of Culex quinquefasciatus. This work describes the effect of six α,β-unsaturated lactones (5a-5f) on survival of A. aegypti fourth instar larvae (L4). It is also reported the effects of the lactones on L4 gut trypsin activity and oviposition behavior of A. aegypti females. Five lactones were able to kill L4 being the lactones 5a (LC50 of 39.05 ppm), 5e (LC50 of 36.30 ppm) and 5f (LC50 of 40.46 ppm) the most promising larvicides. Only the lactone 5a inhibited L4 gut trypsin activity, with an IC50 of 115.15 µg/mL. Lactones 5a, 5c, 5d and 5e did not exert deterrent or stimulatory effects on oviposition, whereas lactone 5b exhibited a strong deterrent oviposition activity. In conclusion, this work introduces new α,β-unsaturated lactones as promising alternatives to control A. aegypti dissemination. The larvicidal mechanism of the lactone 5a can involve the disruption of proteolysis at larval gut.

  7. Targeting gene expression to the female larval fat body of transgenic Aedes aegypti mosquitoes.

    PubMed

    Totten, D C; Vuong, M; Litvinova, O V; Jinwal, U K; Gulia-Nuss, M; Harrell, R A; Beneš, H

    2013-02-01

    As the fat body is a critical tissue for mosquito development, metamorphosis, immune and reproductive system function, the characterization of regulatory modules targeting gene expression to the female mosquito fat body at distinct life stages is much needed for multiple, varied strategies for controlling vector-borne diseases such as dengue and malaria. The hexameric storage protein, Hexamerin-1.2, of the mosquito Aedes atropalpus is female-specific and uniquely expressed in the fat body of fourth instar larvae and young adults. We have identified in the Hex-1.2 gene, a short regulatory module that directs female-, tissue-, and stage-specific lacZ reporter gene expression using a heterologous promoter in transgenic lines of the dengue vector Aedes aegypti. Male transgenic larvae and pupae of one line expressed no Escherichia coli β-galactosidase or transgene product; in two other lines reporter gene activity was highly female-biased. All transgenic lines expressed the reporter only in the fat body; however, lacZ mRNA levels were no different in males and females at any stage examined, suggesting that the gene regulatory module drives female-specific expression by post-transcriptional regulation in the heterologous mosquito. This regulatory element from the Hex-1.2 gene thus provides a new molecular tool for transgenic mosquito control as well as functional genetic analysis in aedine mosquitoes.

  8. Effects of Croton rhamnifolioides essential oil on Aedes aegypti oviposition, larval toxicity and trypsin activity.

    PubMed

    Santos, Geanne K N; Dutra, Kamilla A; Lira, Camila S; Lima, Bheatriz N; Napoleão, Thiago H; Paiva, Patrícia M G; Maranhão, Claudia A; Brandão, Sofia S F; Navarro, Daniela M A F

    2014-01-01

    Although numerous reports are available concerning the larvicidal potential of essential oils, very few investigations have focused on their mechanisms of action. In the present study, we have investigated the chemical composition of the leaf oil of Croton rhamnifolioides during storage and its effects on oviposition and survival of larvae of the dengue fever mosquito Aedes aegypti. In addition, we have established a possible mechanism of action for the larvicidal activity of the essential oil. GC-MS analyses revealed marked differences in the composition of oil that had been freshly isolated and that of a sample that had been stored in a sealed amber-glass vial under refrigeration for three years. However, both fresh and stored oil exhibited substantial larvicidal activities with LC50 values of 122.35 and 89.03 ppm, respectively, and oviposition deterrent effects against gravid females at concentrations of 50 and 100 µg·mL-1. These results demonstrate that the larvicidal effect of the essential oil was unchanged during three years of storage even though its chemical composition altered. Hence, the essential oil could be used in the preparation of commercial products. In addition, we observed that the trypsin-like activity of mosquito larvae was inhibited in vitro by the essential oil of C. rhamnifolioides, suggesting that the larvicidal effect may be associated with inhibition of this enzyme.

  9. Effects of Croton rhamnifolioides essential oil on Aedes aegypti oviposition, larval toxicity and trypsin activity.

    PubMed

    Santos, Geanne K N; Dutra, Kamilla A; Lira, Camila S; Lima, Bheatriz N; Napoleão, Thiago H; Paiva, Patrícia M G; Maranhão, Claudia A; Brandão, Sofia S F; Navarro, Daniela M A F

    2014-01-01

    Although numerous reports are available concerning the larvicidal potential of essential oils, very few investigations have focused on their mechanisms of action. In the present study, we have investigated the chemical composition of the leaf oil of Croton rhamnifolioides during storage and its effects on oviposition and survival of larvae of the dengue fever mosquito Aedes aegypti. In addition, we have established a possible mechanism of action for the larvicidal activity of the essential oil. GC-MS analyses revealed marked differences in the composition of oil that had been freshly isolated and that of a sample that had been stored in a sealed amber-glass vial under refrigeration for three years. However, both fresh and stored oil exhibited substantial larvicidal activities with LC50 values of 122.35 and 89.03 ppm, respectively, and oviposition deterrent effects against gravid females at concentrations of 50 and 100 µg·mL-1. These results demonstrate that the larvicidal effect of the essential oil was unchanged during three years of storage even though its chemical composition altered. Hence, the essential oil could be used in the preparation of commercial products. In addition, we observed that the trypsin-like activity of mosquito larvae was inhibited in vitro by the essential oil of C. rhamnifolioides, suggesting that the larvicidal effect may be associated with inhibition of this enzyme. PMID:25317582

  10. Affinity purification and characterization of a biodegradable plastic-degrading enzyme from a yeast isolated from the larval midgut of a stag beetle, Aegus laevicollis.

    PubMed

    Suzuki, Ken; Sakamoto, Hironori; Shinozaki, Yukiko; Tabata, Jun; Watanabe, Takashi; Mochizuki, Atsushi; Koitabashi, Motoo; Fujii, Takeshi; Tsushima, Seiya; Kitamoto, Hiroko K

    2013-09-01

    Two yeast strains, which have the ability to degrade biodegradable plastic films, were isolated from the larval midgut of a stag beetle, Aegus laevicollis. Both of them are most closely related to Cryptococcus magnus and could degrade biodegradable plastic (BP) films made of poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PBSA) effectively. A BP-degrading enzyme was purified from the culture broth of one of the isolated strains employing a newly developed affinity purification method based on the binding action of the enzyme to the substrate (emulsified PBSA) and its subsequent degradative action toward the substrate. Partial amino acid sequences of this enzyme suggested that it belongs to the cutinase family, and thus, the enzyme was named CmCut1. It has a molecular mass of 21 kDa and a degradative activity for emulsified PBSA which was significantly enhanced by the simultaneous presence of Ca(2+) or Mg(2+) at a concentration of about 2.5 mM. Its optimal pH was 7.5, and the optimal temperature was 40 °C. It showed a broad substrate specificity for p-nitrophenyl (pNP)-fatty acid esters ranging from pNP-acetate (C2) to pNP-stearate (C18) and films of PBSA, PBS, poly(ε-caprolactone), and poly(lactic acid).

  11. Larval Development of Aedes aegypti and Aedes albopictus in Peri-Urban Brackish Water and Its Implications for Transmission of Arboviral Diseases

    PubMed Central

    Ramasamy, Ranjan; Surendran, Sinnathamby N.; Jude, Pavilupillai J.; Dharshini, Sangaralingam; Vinobaba, Muthuladchumy

    2011-01-01

    Aedes aegypti (Linnaeus) and Aedes albopictus Skuse mosquitoes transmit serious human arboviral diseases including yellow fever, dengue and chikungunya in many tropical and sub-tropical countries. Females of the two species have adapted to undergo preimaginal development in natural or artificial collections of freshwater near human habitations and feed on human blood. While there is an effective vaccine against yellow fever, the control of dengue and chikungunya is mainly dependent on reducing freshwater preimaginal development habitats of the two vectors. We show here that Ae. aegypti and Ae. albopictus lay eggs and their larvae survive to emerge as adults in brackish water (water with <0.5 ppt or parts per thousand, 0.5–30 ppt and >30 ppt salt are termed fresh, brackish and saline respectively). Brackish water with salinity of 2 to 15 ppt in discarded plastic and glass containers, abandoned fishing boats and unused wells in coastal peri-urban environment were found to contain Ae. aegypti and Ae. albopictus larvae. Relatively high incidence of dengue in Jaffna city, Sri Lanka was observed in the vicinity of brackish water habitats containing Ae. aegypti larvae. These observations raise the possibility that brackish water-adapted Ae. aegypti and Ae. albopictus may play a hitherto unrecognized role in transmitting dengue, chikungunya and yellow fever in coastal urban areas. National and international health authorities therefore need to take the findings into consideration and extend their vector control efforts, which are presently focused on urban freshwater habitats, to include brackish water larval development habitats. PMID:22132243

  12. Sequence analysis and molecular characterization of larval midgut cDNA transcripts encoding peptidases from the yellow mealworm, Tenebrio molitor L.

    PubMed

    Prabhakar, S; Chen, M-S; Elpidina, E N; Vinokurov, K S; Smith, C M; Marshall, J; Oppert, B

    2007-08-01

    Peptidase sequences were analysed in randomly picked clones from cDNA libraries of the anterior or posterior midgut or whole larvae of the yellow mealworm, Tenebrio molitor Linnaeus. Of a total of 1528 sequences, 92 encoded potential peptidases, from which 50 full-length cDNA sequences were obtained, including serine and cysteine proteinases and metallopeptidases. Serine proteinase transcripts were predominant in the posterior midgut, whereas transcripts encoding cysteine and metallopeptidases were mainly found in the anterior midgut. Alignments with other proteinases indicated that 40% of the serine proteinase sequences were serine proteinase homologues, and the remaining ones were identified as either trypsin, chymotrypsin or other serine proteinases. Cysteine proteinase sequences included cathepsin B- and L-like proteinases, and metallopeptidase transcripts were similar to carboxypeptidase A. Northern blot analysis of representative sequences demonstrated the differential expression profile of selected transcripts across five developmental stages of Te. molitor. These sequences provide insights into peptidases in coleopteran insects as a basis to study the response of coleopteran larvae to external stimuli and to evaluate regulatory features of the response.

  13. The essential oil of Brazilian pepper, Schinus terebinthifolia Raddi in larval control of Stegomyia aegypti (Linnaeus, 1762)

    PubMed Central

    2010-01-01

    Background The ability of mosquitoes of the genus Aedes and its allies, such as Stegomyia, to transmit diseases such as dengue and yellow fever, makes them important in public health. This study aims to evaluate the use of the essential oil of Brazilian pepper in biological control of by assessing and quantifying the larvicidal effect against S. aegypti, the only available access to dengue control, and test its risk of genotoxicity with Salmonella typhimurium as an indicator of safety for its environmental use. Results The density of the oil was 0.8622 g mL-1. Gas chromatography coupled with mass spectrometry revealed six major constituents: δ-3-carene (55.43%), α-pinene (16.25%), sylvestrene (10.67%), germacrene D (2.17), β-myrcene (1.99%), and isoterpinolene (1.4%). The minimum inhibitory dose to larvae development was 862.20 μg mL-1. The median lethal dose (LD50) of the essential oil for larvae was between the concentrations of 172.44-344.88 μg mL-1. There was no mutagenic risk for the essential oil, since there were no biochemical or morphological changes in S. typhimurium after exposure to the essential oil. Conclusions The minimum inhibitory essential oil concentration and the median lethal dose pointed to the value of the use of water dispersions of Brazilian pepper essential oil as an environmental safe natural larvicidal for S. aegypti. PMID:20799936

  14. Control of larval and egg development in Aedes aegypti with Ribonucleic acid interference (RNAi) against juvenile hormone acid methyl transferase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ribonucleic acid interference (RNAi) is a powerful approach for elucidating gene functions in a variety of organisms, including mosquitoes and many other insects. Little has been done, however, to harness this approach in order to control adult and larval mosquitoes. Juvenile hormone (JH) plays a pi...

  15. Selective inhibitors of digestive enzymes from Aedes aegypti larvae identified by phage display.

    PubMed

    Soares, Tatiane Sanches; Soares Torquato, Ricardo Jose; Alves Lemos, Francisco Jose; Tanaka, Aparecida Sadae

    2013-01-01

    Dengue is a serious disease transmitted by the mosquito Aedes aegypti during blood meal feeding. It is estimated that the dengue virus is transmitted to millions of individuals each year in tropical and subtropical areas. Dengue control strategies have been based on controlling the vector, Ae. aegypti, using insecticide, but the emergence of resistance poses new challenges. The aim of this study was the identification of specific protease inhibitors of the digestive enzymes from Ae. aegypti larvae, which may serve as a prospective alternative biocontrol method. High affinity protein inhibitors were selected by all of the digestive serine proteases of the 4th instar larval midgut, and the specificity of these inhibitors was characterized. These inhibitors were obtained from a phage library displaying variants of HiTI, a trypsin inhibitor from Haematobia irritans, that are mutated in the reactive loop (P1-P4'). Based on the selected amino acid sequence pattern, seven HiTI inhibitor variants were cloned, expressed and purified. The results indicate that the HiTI variants named T6 (RGGAV) and T128 (WNEGL) were selected by larval trypsin-like (IC(50) of 1.1 nM) and chymotrypsin-like enzymes (IC(50) of 11.6 nM), respectively. The variants T23 (LLGGL) and T149 (GGVWR) inhibited both larval chymotrypsin-like (IC(50) of 4.2 nM and 29.0 nM, respectively) and elastase-like enzymes (IC(50) of 1.2 nM for both). Specific inhibitors were successfully obtained for the digestive enzymes of Ae. aegypti larvae by phage display. Our data also strongly suggest the presence of elastase-like enzymes in Ae. aegypti larvae. The HiTI variants T6 and T23 are good candidates for the development as a larvicide to control the vector.

  16. A single major QTL controls expression of larval Cry1F resistance trait in Ostrinia nubilalis (Lepidoptera: Crambidae) and is independent of midgut receptor genes.

    PubMed

    Coates, Brad S; Sumerford, Douglas V; Lopez, Miriam D; Wang, Haichuan; Fraser, Lisa M; Kroemer, Jeremy A; Spencer, Terrence; Kim, Kyung S; Abel, Craig A; Hellmich, Richard L; Siegfried, Blair D

    2011-08-01

    The European corn borer, Ostrinia nubilalis (Lepidoptera: Crambidae), is an introduced crop pest in North America that causes major damage to corn and reduces yield of food, feed, and biofuel materials. The Cry1F toxin from Bacillus thuringiensis (Bt) expressed in transgenic hybrid corn is highly toxic to O. nubilalis larvae and effective in minimizing feeding damage. A laboratory colony of O. nubilalis was selected for high levels of Cry1F resistance (>12,000-fold compared to susceptible larvae) and is capable of survival on transgenic hybrid corn. Genetic linkage maps with segregating AFLP markers show that the Cry1F resistance trait is controlled by a single quantitative trait locus (QTL) on linkage group 12. The map position of single nucleotide polymorphism (SNP) markers indicated that midgut Bt toxin-receptor genes, alkaline phosphatase, aminopeptidase N, and cadherin, are not linked with the Cry1F QTL. Evidence suggests that genes within this genome interval may give rise to a novel Bt toxin resistance trait for Lepidoptera that appears independent of known receptor-based mechanisms of resistance.

  17. A single major QTL controls expression of larval Cry1F resistance trait in Ostrinia nubilalis (Lepidoptera: Crambidae) and is independent of midgut receptor genes.

    PubMed

    Coates, Brad S; Sumerford, Douglas V; Lopez, Miriam D; Wang, Haichuan; Fraser, Lisa M; Kroemer, Jeremy A; Spencer, Terrence; Kim, Kyung S; Abel, Craig A; Hellmich, Richard L; Siegfried, Blair D

    2011-08-01

    The European corn borer, Ostrinia nubilalis (Lepidoptera: Crambidae), is an introduced crop pest in North America that causes major damage to corn and reduces yield of food, feed, and biofuel materials. The Cry1F toxin from Bacillus thuringiensis (Bt) expressed in transgenic hybrid corn is highly toxic to O. nubilalis larvae and effective in minimizing feeding damage. A laboratory colony of O. nubilalis was selected for high levels of Cry1F resistance (>12,000-fold compared to susceptible larvae) and is capable of survival on transgenic hybrid corn. Genetic linkage maps with segregating AFLP markers show that the Cry1F resistance trait is controlled by a single quantitative trait locus (QTL) on linkage group 12. The map position of single nucleotide polymorphism (SNP) markers indicated that midgut Bt toxin-receptor genes, alkaline phosphatase, aminopeptidase N, and cadherin, are not linked with the Cry1F QTL. Evidence suggests that genes within this genome interval may give rise to a novel Bt toxin resistance trait for Lepidoptera that appears independent of known receptor-based mechanisms of resistance. PMID:21822602

  18. Multi-scale analysis of the associations among egg, larval and pupal surveys and the presence and abundance of adult female Aedes aegypti (Stegomyia aegypti) in the city of Merida, Mexico.

    PubMed

    Manrique-Saide, P; Coleman, P; McCall, P J; Lenhart, A; Vázquez-Prokopec, G; Davies, C R

    2014-09-01

    Despite decades of research, there is still no agreement on which indices of Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) presence and abundance better quantify entomological risk for dengue. This study reports the results of a multi-scale, cross-sectional entomological survey carried out in 1160 households in the city of Merida, Mexico to establish: (a) the correlation between levels of Ae. aegypti presence and abundance detected with aspirators and ovitraps; (b) which immature and egg indices correlate with the presence and abundance of Ae. aegypti females, and (c) the correlations amongst traditional Aedes indices and their modifications for pupae at the household level and within medium-sized geographic areas used for vector surveillance. Our analyses show that ovitrap positivity was significantly associated with indoor adult Ae. aegypti presence [odds ratio (OR) = 1.50; P = 0.03], that the presence of pupae is associated with adult presence at the household level (OR = 2.27; P = 0.001), that classic Aedes indices are informative only when they account for pupae, and that window screens provide a significant level of protection against peridomestic Ae. aegypti (OR = 0.59; P = 0.02). Results reinforce the potential of using both positive collections in outdoor ovitraps and the presence of pupae as sensitive indicators of indoor adult female presence. PMID:24797405

  19. Multi-scale analysis of the associations among egg, larval and pupal surveys and the presence and abundance of adult female Aedes aegypti (Stegomyia aegypti) in the city of Merida, Mexico.

    PubMed

    Manrique-Saide, P; Coleman, P; McCall, P J; Lenhart, A; Vázquez-Prokopec, G; Davies, C R

    2014-09-01

    Despite decades of research, there is still no agreement on which indices of Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) presence and abundance better quantify entomological risk for dengue. This study reports the results of a multi-scale, cross-sectional entomological survey carried out in 1160 households in the city of Merida, Mexico to establish: (a) the correlation between levels of Ae. aegypti presence and abundance detected with aspirators and ovitraps; (b) which immature and egg indices correlate with the presence and abundance of Ae. aegypti females, and (c) the correlations amongst traditional Aedes indices and their modifications for pupae at the household level and within medium-sized geographic areas used for vector surveillance. Our analyses show that ovitrap positivity was significantly associated with indoor adult Ae. aegypti presence [odds ratio (OR) = 1.50; P = 0.03], that the presence of pupae is associated with adult presence at the household level (OR = 2.27; P = 0.001), that classic Aedes indices are informative only when they account for pupae, and that window screens provide a significant level of protection against peridomestic Ae. aegypti (OR = 0.59; P = 0.02). Results reinforce the potential of using both positive collections in outdoor ovitraps and the presence of pupae as sensitive indicators of indoor adult female presence.

  20. Aspen defense chemicals influence midgut bacterial community composition of gypsy moth.

    PubMed

    Mason, Charles J; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2015-01-01

    Microbial symbionts are becoming increasingly recognized as mediators of many aspects of plant - herbivore interactions. However, the influence of plant chemical defenses on gut associates of insect herbivores is less well understood. We used gypsy moth (Lymantria dispar L.), and differing trembling aspen (Populus tremuloides Michx.) genotypes that vary in chemical defenses, to assess the influence of foliar chemistry on bacterial communities of larval midguts. We evaluated the bacterial community composition of foliage, and of midguts of larvae feeding on those leaves, using next-generation high-throughput sequencing. Plant defense chemicals did not influence the composition of foliar communities. In contrast, both phenolic glycosides and condensed tannins affected the bacterial consortia of gypsy moth midguts. The two most abundant operational taxonomic units were classified as Ralstonia and Acinetobacter. The relative abundance of Ralstonia was higher in midguts than in foliage when phenolic glycoside concentrations were low, but lower in midguts when phenolic glycosides were high. In contrast, the relative abundance of Ralstonia was lower in midguts than in foliage when condensed tannin concentrations were low, but higher in midguts when condensed tannins were high. Acinetobacter showed a different relationship with host chemistry, being relatively more abundant in midguts than with foliage when condensed tannin concentrations were low, but lower in midguts when condensed tannins were high. Acinetobacter tended to have a greater relative abundance in midguts of insects feeding on genotypes with high phenolic glycoside concentrations. These results show that plant defense chemicals influence herbivore midgut communities, which may in turn influence host utilization.

  1. Disposable containers as larval habitats for Aedes aegypti in a city with regular refuse collection: a study in Marília, São Paulo State, Brazil.

    PubMed

    Mazine, C A; Macoris, M L; Andrighetti, M T; Yasumaro, S; Silva, M E; Nelson, M J; Winch, P J

    1996-09-01

    In Marília, Brazil, refuse is collected at least every other day, yet non-useful, non-returnable containers such as cans, plastic bottles and tires account for almost half of the container habitats found positive for the Aedes aegypti mosquito. A study was therefore conducted to investigate why these containers exist despite regular refuse collection and a high level of awareness of dengue prevention, and how the control program could most effectively respond. Differing community perceptions as to what constitutes refuse were found to lead people to store a variety of containers in their yard. Other dimensions of the problem include the presence of informal refuse collectors in search of saleable materials, and dumping of refuse in vacant lots and along roads. An intervention based on these data will involve the informal refuse collectors in implementation of a community-based recycling project.

  2. Disposable containers as larval habitats for Aedes aegypti in a city with regular refuse collection: a study in Marília, São Paulo State, Brazil.

    PubMed

    Mazine, C A; Macoris, M L; Andrighetti, M T; Yasumaro, S; Silva, M E; Nelson, M J; Winch, P J

    1996-09-01

    In Marília, Brazil, refuse is collected at least every other day, yet non-useful, non-returnable containers such as cans, plastic bottles and tires account for almost half of the container habitats found positive for the Aedes aegypti mosquito. A study was therefore conducted to investigate why these containers exist despite regular refuse collection and a high level of awareness of dengue prevention, and how the control program could most effectively respond. Differing community perceptions as to what constitutes refuse were found to lead people to store a variety of containers in their yard. Other dimensions of the problem include the presence of informal refuse collectors in search of saleable materials, and dumping of refuse in vacant lots and along roads. An intervention based on these data will involve the informal refuse collectors in implementation of a community-based recycling project. PMID:8971274

  3. Alkaline phosphatases and aminopeptidases are altered in a Cry11Aa resistant strain of Aedes aegypti.

    PubMed

    Lee, Su-Bum; Aimanova, Karlygash G; Gill, Sarjeet S

    2014-11-01

    Bacillus thuringiensis subsp. israelensis (Bti) is widely used for the biological control of mosquito populations. However, the mechanism of Bti toxins is still not fully understood. To further elucidate the mechanism of Bti toxins, we developed an Aedes aegypti resistant strain that shows high-level resistance to Cry11Aa toxin. After 27 selections with Cry11Aa toxin, the larvae showed a 124-fold resistance ratio for Cry11Aa (strain G30). G30 larvae showed cross-resistance to Cry4Aa (66-fold resistance), less to Cry4Ba (13-fold), but not to Cry11Ba (2-fold). Midguts from these resistant larvae did not show detectable difference in the processing of the Cry11Aa toxin compared to that in susceptible larvae (WT). Brush border membrane vesicles (BBMV) from resistant larvae bound slightly less Cry11Aa compared to WT BBMV. To identify potential proteins associated with Cry11A resistance, not only transcript changes in the larval midgut were analyzed using Illumina sequencing and qPCR, but alterations of previously identified receptor proteins were investigated using immunoblots. The transcripts of 375 genes were significantly increased and those of 208 genes were down regulated in the resistant larvae midgut compared to the WT. None of the transcripts for previously identified receptors of Cry11Aa (Aedes cadherin, ALP1, APN1, and APN2) were altered in these analyses. The genes for the identified functional receptors in resistant larvae midgut did not contain any mutation in their sequences nor was there any change in their transcript expression levels compared to WT. However, ALP proteins were expressed at reduced levels (∼ 40%) in the resistant strain BBMV. APN proteins and their activity were also slightly reduced in resistance strain. The transcript levels of ALPs (AAEL013330 and AAEL015070) and APNs (AAEL008158, AAEL008162) were significantly reduced. These results strongly suggest that ALPs and APNs could be associated with Cry11Aa resistance in Ae. aegypti. PMID

  4. Aspen defense chemicals influence midgut bacterial community composition of gypsy moth.

    PubMed

    Mason, Charles J; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2015-01-01

    Microbial symbionts are becoming increasingly recognized as mediators of many aspects of plant - herbivore interactions. However, the influence of plant chemical defenses on gut associates of insect herbivores is less well understood. We used gypsy moth (Lymantria dispar L.), and differing trembling aspen (Populus tremuloides Michx.) genotypes that vary in chemical defenses, to assess the influence of foliar chemistry on bacterial communities of larval midguts. We evaluated the bacterial community composition of foliage, and of midguts of larvae feeding on those leaves, using next-generation high-throughput sequencing. Plant defense chemicals did not influence the composition of foliar communities. In contrast, both phenolic glycosides and condensed tannins affected the bacterial consortia of gypsy moth midguts. The two most abundant operational taxonomic units were classified as Ralstonia and Acinetobacter. The relative abundance of Ralstonia was higher in midguts than in foliage when phenolic glycoside concentrations were low, but lower in midguts when phenolic glycosides were high. In contrast, the relative abundance of Ralstonia was lower in midguts than in foliage when condensed tannin concentrations were low, but higher in midguts when condensed tannins were high. Acinetobacter showed a different relationship with host chemistry, being relatively more abundant in midguts than with foliage when condensed tannin concentrations were low, but lower in midguts when condensed tannins were high. Acinetobacter tended to have a greater relative abundance in midguts of insects feeding on genotypes with high phenolic glycoside concentrations. These results show that plant defense chemicals influence herbivore midgut communities, which may in turn influence host utilization. PMID:25475786

  5. Sucrose hydrolases from the midgut of the sugarcane stalk borer Diatraea saccharalis.

    PubMed

    Carneiro, Cíntia N B; Isejima, Eliza M; Samuels, Richard I; Silva, Carlos P

    2004-11-01

    A beta-fructosidase (EC 3.2.1.26) was isolated from the midgut of larval sugar cane stalk borer Diatraea saccharalis by mild-denaturing electrophoresis and further purified to near homogeneity by gel filtration. beta-Fructosidase hydrolysed sucrose, raffinose and the fructosyl-trisaccharide isokestose, but it had no activity against maltose, melibiose and synthetic substrates for alpha-glucosidases. Two other sucrose hydrolases, one resembling a alpha-glucosidase (EC 3.2.1.20) and the other one active specifically against sucrose (sucrase) were detected in the larval midgut of D. saccharalis. All three sucrose hydrolases were associated with the midgut epithelium of larval D. saccharalis. Relative molecular mass (M(r)) of the beta-fructosidase was estimated around 45,000 (by gel filtration). The other two sucrose hydrolases had M(r) of 54,000 (alpha-glucosidase) and 59,000 (sucrase). The pH optima of the sucrose hydrolases were 5-10 for both alpha-glucosidase and sucrase and 7-8 for beta-fructosidase. Considering V(max)/K(m) ratios, beta-fructosidase preferentially cleaves isokestose rather than raffinose and sucrose. In order to evaluate the possible contribution of microorganisms isolated from the midgut to the pool of sucrose hydrolases, washed midgut epithelia were homogenised and plated onto appropriate media. Seven bacterial and one yeast species were isolated. None of the sucrose hydrolases extracted from the microorganisms corresponded to the enzymes isolated from midgut tissue homogenates. This result suggests that the major sucrose hydrolases found in the midgut of larval D. saccharalis were probably produced by the insect themselves not by the gut microflora.

  6. In vivo identification of Bacillus thuringiensis Cry4Ba toxin receptors by RNA interference knockdown of glycosylphosphatidylinositol-linked aminopeptidase N transcripts in Aedes aegypti larvae.

    PubMed

    Saengwiman, Suchada; Aroonkesorn, Aratee; Dedvisitsakul, Plaipol; Sakdee, Somsri; Leetachewa, Somphob; Angsuthanasombat, Chanan; Pootanakit, Kusol

    2011-04-22

    Bacillus thuringiensis Cry4Ba toxin selectively kills Aedes aegypti mosquito larvae as it is in part due to the presence of specific membrane-bound protein receptors. In this study, using data mining approach, we initially identified three potential glycosylphosphatidylinositol-linked aminopeptidase N (GPI-APN) isoforms, APN2778, APN2783 and APN5808, which are believed to act as Cry4Ba toxin receptors. These three isoforms that are functionally expressed in the larval midgut can be sequence-specific knocked down (ranging from ∼80 % to 95 %) by soaking the Aedes aegypti larvae in buffer of long double-stranded GPI-APN RNAs (∼300-680 bp). Finally, to see the physiological effect of APN knockdowns, the larvae were fed with Escherichia coli expressing Cry4Ba toxin. The results revealed that all the three identified GPI-APN isoforms may possibly function as a Cry4Ba receptor, particularly for APN2783 as those larvae with this transcript knockdown showed a dramatic increase in resistance to Cry4Ba toxicity. PMID:21439264

  7. Two specific membrane-bound aminopeptidase N isoforms from Aedes aegypti larvae serve as functional receptors for the Bacillus thuringiensis Cry4Ba toxin implicating counterpart specificity.

    PubMed

    Aroonkesorn, Aratee; Pootanakit, Kusol; Katzenmeier, Gerd; Angsuthanasombat, Chanan

    2015-05-29

    The interaction between Bacillus thuringiensis Cry toxins and their receptors on midgut cells of susceptible insect larvae is the critical determinant in toxin specificity. Besides GPI-linked alkaline phosphatase in Aedes aegypti mosquito-larval midguts, membrane-bound aminopeptidase N (AaeAPN) is widely thought to serve as a Cry4Ba receptor. Here, two full-length AaeAPN isoforms, AaeAPN2778 and AaeAPN2783, predicted to be GPI-linked were cloned and successfully expressed in Spodoptera frugiperda (Sf9) cells as 112- and 107-kDa membrane-bound proteins, respectively. In the cytotoxicity assay, Sf9 cells expressing each of the two AaeAPN isoforms showed increased sensitivity to the Cry4Ba mosquito-active toxin. Double immunolocalization revealed specific binding of Cry4Ba to each individual AaeAPN expressed on the cell membrane surface. Sequence analysis and homology-based modeling placed these two AaeAPNs to the M1 aminopeptidase family as they showed similar four-domain structures, with the most conserved domain II being the catalytic component. Additionally, the most variable domain IV containing negatively charged surface patches observed only in dipteran APNs could be involved in insect specificity. Overall results demonstrated that these two membrane-bound APN isoforms were responsible for mediating Cry4Ba toxicity against AaeAPN-expressed Sf9 cells, suggesting their important role as functional receptors for the toxin counterpart in A. aegypti mosquito larvae. PMID:25871797

  8. Comparative efficacy of existing surveillance tools for Aedes aegypti in Western Kenya.

    PubMed

    Yalwala, Sancto; Clark, Jeffrey; Oullo, David; Ngonga, Daniel; Abuom, David; Wanja, Elizabeth; Bast, Joshua

    2015-12-01

    All traditional surveillance techniques for Aedes aegypti have been developed for the cosmopolitan domestic subspecies Ae. aegypti aegypti, and not the sylvatic subspecies, Ae. aegypti formosus. The predominant form in Western Kenya is Ae. aegypti formosus that is rarely associated with human habitations but is linked to transmission of sylvatic dengue virus strains. We compared five surveillance methods for their effectiveness in sampling Ae. aegypti formosus with the goal of determining a sustainable surveillance strategy in Kenya. The methods included larval and pupal surveys, oviposition trapping, BG-Sentinel trapping, resting boxes, and backpack aspirations. Larval and pupal surveys collected the highest number of Ae. aegypti formosus (51.3%), followed by oviposition traps (45.7%), BG-Sentinel traps (3.0%), and zero collected with either backpack aspiration or resting box collections. No Ae. aegypti formosus larvae or pupae were found indoors. The results indicate that oviposition traps and outdoor larval and pupal surveys were better surveillance methods for Ae. aegypti formosus in Western Kenya. PMID:26611965

  9. Comparative efficacy of existing surveillance tools for Aedes aegypti in Western Kenya.

    PubMed

    Yalwala, Sancto; Clark, Jeffrey; Oullo, David; Ngonga, Daniel; Abuom, David; Wanja, Elizabeth; Bast, Joshua

    2015-12-01

    All traditional surveillance techniques for Aedes aegypti have been developed for the cosmopolitan domestic subspecies Ae. aegypti aegypti, and not the sylvatic subspecies, Ae. aegypti formosus. The predominant form in Western Kenya is Ae. aegypti formosus that is rarely associated with human habitations but is linked to transmission of sylvatic dengue virus strains. We compared five surveillance methods for their effectiveness in sampling Ae. aegypti formosus with the goal of determining a sustainable surveillance strategy in Kenya. The methods included larval and pupal surveys, oviposition trapping, BG-Sentinel trapping, resting boxes, and backpack aspirations. Larval and pupal surveys collected the highest number of Ae. aegypti formosus (51.3%), followed by oviposition traps (45.7%), BG-Sentinel traps (3.0%), and zero collected with either backpack aspiration or resting box collections. No Ae. aegypti formosus larvae or pupae were found indoors. The results indicate that oviposition traps and outdoor larval and pupal surveys were better surveillance methods for Ae. aegypti formosus in Western Kenya.

  10. Acquisition and structuring of midgut bacterial communities in gypsy moth (Lepidoptera: Erebidae) larvae.

    PubMed

    Mason, Charles J; Raffa, Kenneth F

    2014-06-01

    Insects are associated with a diversity of bacteria that colonize their midguts. The extent to which these communities reflect maternal transmission, environmental acquisition, and subsequent structuring by the extreme conditions within the insect gut are poorly understood in many species. We used gypsy moth (Lymantria dispar L.) as a model to investigate interactions between egg mass and environmental sources of bacteria on larval midgut communities. Egg masses were collected from several wild and laboratory populations, and the effects of diet, initial egg mass community, and internal host environment were evaluated using 454 16S-rRNA gene pyrosequencing. Wild populations were highly diverse, while laboratory-maintained egg masses were associated with few operational taxonomic units. As larvae developed, their midgut bacterial communities became more similar to each other and the consumed diet despite initial differences in egg mass-associated bacteria. Subsequent experiments revealed that while midgut membership was more similar to bacteria associated with diet than with egg mass-associated bacteria, we were unable to detect distinct, persistent differences attributable to specific host plants. The differences between foliar communities and midgut communities of larvae that ingested them were owing to relative changes in populations of several bacteria phylotypes. We conclude that gypsy moth has a relatively characteristic midgut bacterial community that is reflective of, but ultimately distinct from, its foliar diet. This work demonstrates that environmental acquisition of diverse microbes can lead to similar midgut bacterial assemblages, underscoring the importance of host physiological environment in structuring bacterial communities. PMID:24780292

  11. Acquisition and structuring of midgut bacterial communities in gypsy moth (Lepidoptera: Erebidae) larvae.

    PubMed

    Mason, Charles J; Raffa, Kenneth F

    2014-06-01

    Insects are associated with a diversity of bacteria that colonize their midguts. The extent to which these communities reflect maternal transmission, environmental acquisition, and subsequent structuring by the extreme conditions within the insect gut are poorly understood in many species. We used gypsy moth (Lymantria dispar L.) as a model to investigate interactions between egg mass and environmental sources of bacteria on larval midgut communities. Egg masses were collected from several wild and laboratory populations, and the effects of diet, initial egg mass community, and internal host environment were evaluated using 454 16S-rRNA gene pyrosequencing. Wild populations were highly diverse, while laboratory-maintained egg masses were associated with few operational taxonomic units. As larvae developed, their midgut bacterial communities became more similar to each other and the consumed diet despite initial differences in egg mass-associated bacteria. Subsequent experiments revealed that while midgut membership was more similar to bacteria associated with diet than with egg mass-associated bacteria, we were unable to detect distinct, persistent differences attributable to specific host plants. The differences between foliar communities and midgut communities of larvae that ingested them were owing to relative changes in populations of several bacteria phylotypes. We conclude that gypsy moth has a relatively characteristic midgut bacterial community that is reflective of, but ultimately distinct from, its foliar diet. This work demonstrates that environmental acquisition of diverse microbes can lead to similar midgut bacterial assemblages, underscoring the importance of host physiological environment in structuring bacterial communities.

  12. Engineering RNA interference-based resistance to dengue virus type 2 in genetically modified Aedes aegypti.

    PubMed

    Franz, Alexander W E; Sanchez-Vargas, Irma; Adelman, Zach N; Blair, Carol D; Beaty, Barry J; James, Anthony A; Olson, Ken E

    2006-03-14

    Mosquitoes (Aedes aegypti) were genetically modified to exhibit impaired vector competence for dengue type 2 viruses (DENV-2). We exploited the natural antiviral RNA interference (RNAi) pathway in the mosquito midgut by constructing an effector gene that expresses an inverted-repeat (IR) RNA derived from the premembrane protein coding region of the DENV-2 RNA genome. The A. aegypti carboxypeptidase A promoter was used to express the IR RNA in midgut epithelial cells after ingestion of a bloodmeal. The promoter and effector gene were inserted into the genome of a white-eye Puerto Rico Rexville D (Higgs' white eye) strain by using the nonautonomous mariner MosI transformation system. A transgenic family, Carb77, expressed IR RNA in the midgut after a bloodmeal. Carb77 mosquitoes ingesting an artificial bloodmeal containing DENV-2 exhibited marked reduction of viral envelope antigen in midguts and salivary glands after infection. DENV-2 titration of individual mosquitoes showed that most Carb77 mosquitoes poorly supported virus replication. Transmission in vitro of virus from the Carb77 line was significantly diminished when compared to control mosquitoes. The presence of DENV-2-derived siRNAs in RNA extracts from midguts of Carb77 and the loss of the resistance phenotype when the RNAi pathway was interrupted proved that DENV-2 resistance was caused by a RNAi response. Engineering of transgenic A. aegypti that show a high level of resistance against DENV-2 provides a powerful tool for developing population replacement strategies to control transmission of dengue viruses.

  13. Impact on bacterial community in midguts of the Asian corn borer larvae by transgenic Trichoderma strain overexpressing a heterologous chit42 gene with chitin-binding domain.

    PubMed

    Li, Yingying; Fu, Kehe; Gao, Shigang; Wu, Qiong; Fan, Lili; Li, Yaqian; Chen, Jie

    2013-01-01

    This paper is the first report of the impact on the bacterial community in the midgut of the Asian corn borer (Ostrinia furnacalis) by the chitinase from the transgenic Trichoderma strain. In this study, we detected a change of the bacterial community in the midgut of the fourth instar larvae by using a culture-independent method. Results suggested that Proteobacteria and Firmicutes were the most highly represented phyla, being present in all the midgut bacterial communities. The observed species richness was simple, ranging from four to five of all the 16S rRNA clone libraries. When using Trichoderma fermentation liquids as additives, the percentages of the dominant flora in the total bacterial community in larval midgut changed significantly. The community of the genus Ochrobactrum in the midgut decreased significantly when the larvae were fed with the fermentation liquids of the transgenic Trichoderma strain Mc4. However, the Enterococcus community increased and then occupied the vacated niche of the Ochrobactrum members. Furthermore, the Shannon-Wiener (H) and the Simpson (1-D) indexes of the larval midgut bacterial library treated by feeding fermentation liquids of the transgenic Trichoderma strain Mc4 was the lowest compared with the culture medium, fermentation liquids of the wild type strain T30, and the sterile artificial diet. The Enterococcus sp. strain was isolated and characterized from the healthy larvae midgut of the Asian corn borer. An infection study of the Asian corn borer larvae using Enterococcus sp. ACB-1 revealed that a correlation existed between the increased Enterococcus community in the larval midgut and larval mortality. These results demonstrated that the transgenic Trichoderma strain could affect the composition of the midgut bacterial community. The change of the midgut bacterial community might be viewed as one of the factors resulting in the increased mortality of the Asian corn borer larvae.

  14. DNA duplication is essential for the repair of gastrointestinal perforation in the insect midgut

    PubMed Central

    Huang, Wuren; Zhang, Jie; Yang, Bing; Beerntsen, Brenda T.; Song, Hongsheng; Ling, Erjun

    2016-01-01

    Invertebrate animals have the capacity of repairing wounds in the skin and gut via different mechanisms. Gastrointestinal perforation, a hole in the human gastrointestinal system, is a serious condition, and surgery is necessary to repair the perforation to prevent an abdominal abscess or sepsis. Here we report the repair of gastrointestinal perforation made by a needle-puncture wound in the silkworm larval midgut. Following insect gut perforation, only a weak immune response was observed because the growth of Escherichia coli alone was partially inhibited by plasma collected at 6 h after needle puncture of the larval midgut. However, circulating hemocytes did aggregate over the needle-puncture wound to form a scab. While, cell division and apoptosis were not observed at the wound site, the needle puncture significantly enhanced DNA duplication in cells surrounding the wound, which was essential to repair the midgut perforation. Due to the repair capacity and limited immune response caused by needle puncture to the midgut, this approach was successfully used for the injection of small compounds (ethanol in this study) into the insect midgut. Consequently, this needle-puncture wounding of the insect gut can be developed for screening compounds for use as gut chemotherapeutics in the future. PMID:26754166

  15. Regulation of Aedes aegypti Population Dynamics in Field Systems: Quantifying Direct and Delayed Density Dependence

    PubMed Central

    Walsh, Rachael K.; Aguilar, Cristobal L.; Facchinelli, Luca; Valerio, Laura; Ramsey, Janine M.; Scott, Thomas W.; Lloyd, Alun L.; Gould, Fred

    2013-01-01

    Transgenic strains of Aedes aegypti have been engineered to help control transmission of dengue virus. Although resources have been invested in developing the strains, we lack data on the ecology of mosquitoes that could impact the success of this approach. Although studies of intra-specific competition have been conducted using Ae. aegypti larvae, none of these studies examine mixed age cohorts at densities that occur in the field, with natural nutrient levels. Experiments were conducted in Mexico to determine the impact of direct and delayed density dependence on Ae. aegypti populations. Natural water, food, and larval densities were used to estimate the impacts of density dependence on larval survival, development, and adult body size. Direct and delayed density-dependent factors had a significant impact on larval survival, larval development, and adult body size. These results indicate that control methods attempting to reduce mosquito populations may be counteracted by density-dependent population regulation. PMID:23669230

  16. Burchellin: study of bioactivity against Aedes aegypti

    PubMed Central

    2014-01-01

    Background The dengue mosquito Aedes aegypti Linnaeus, 1762 is a widespread insect pest of serious medical importance. Since no effective vaccine is available for treating dengue, the eradication or control of the main mosquito vector is regarded as essential. Since conventional insecticides have limited success, plants may be an alternative source of larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of the neolignan burchellin isolated from Ocotea cymbarum (Lauraceae), a plant from the Amazon region, against third instar larvae of A. aegypti. Methods Burchellin obtained from O. cymbarum was analyzed. The inhibitory activity against A. aegypti eggs and larvae and histological changes in the digestive system of treated L3 larvae were evaluated. In addition, nitric oxide synthase activity and nitric oxide levels were determined, and cytotoxicity bioassays performed. Results The data showed that burchellin interfered with the development cycle of the mosquito, where its strongest toxic effect was 100% mortality in larvae (L3) at concentrations ≥ 30 ppm. This compound did not show target cell toxicity in peritoneal macrophages from BALB/c mice, and proved to have molecular stability when dissolved in water. The L3 and L4 larvae treated with the compound showed cellular destruction and disorganization, cell spacing, and vacuolization of epithelial cells in small regions of the midgut. Conclusion The neolignan burchellin proved to be a strong candidate for a natural, safe and stable phytolarvicidal to be used in population control of A. aegypti. PMID:24713267

  17. Susceptibility of Florida Aedes aegypti and Aedes albopictus to dengue viruses from Puerto Rico.

    PubMed

    Alto, Barry W; Smartt, Chelsea T; Shin, Dongyoung; Bettinardi, David; Malicoate, Jolene; Anderson, Sheri L; Richards, Stephanie L

    2014-12-01

    Locally acquired dengue cases in the continental U.S. are rare. However, outbreaks of dengue-1 during 2009, 2010, and 2013 in Florida and dengue-1 and -2 in Texas suggest vulnerability to transmission. Travel and commerce between Puerto Rico and the U.S. mainland is common, which may pose a risk for traveler-imported dengue cases. Mosquitoes were collected in Florida and used to evaluate their susceptibility to dengue viruses (DENV) from Puerto Rico. Aedes aegypti and Ae. albopictus were susceptible to virus infection with DENV-1 and -2. No significant differences were observed in rates of midgut infection or dissemination between Ae. aegypti or Ae. albopictus for DENV-1 (6-14%). Aedes aegypti was significantly more susceptible to midgut infection with DENV-2 than Ae. albopictus (Ae. aegypti, ∼28%; Ae. albopictus, ∼9%). The dissemination rate with dengue-2 virus for Ae. aegypti (23%) was greater than Ae. albopictus (0%), suggesting that Ae. albopictus is not likely to be an important transmitter of the DENV-2 isolate from Puerto Rico. These results are discussed in light of Florida's vulnerability to DENV transmission.

  18. Oviposition and Embryotoxicity of Indigofera suffruticosa on Early Development of Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Vieira, Jeymesson Raphael Cardoso; Leite, Roberta Maria Pereira; Lima, Izabela Rangel; Navarro, Daniela do Amaral Ferraz; Bianco, Everson Miguel; Leite, Sônia Pereira

    2012-01-01

    Aqueous extract of Indigofera suffruticosa leaves obtained by infusion was used to evaluate the oviposition, its effect on development of eggs and larvae, and morphological changes in larvae of Aedes aegypti. The bioassays were carried out with aqueous extract in different concentrations on eggs, larvae, and female mosquitoes, and the morphological changes were observed in midgut of larvae. The extract showed repellent activity on A. aegypti mosquitoes, reducing significantly the egg laying by females with control substrate (343 (185–406)) compared with the treated substrate (88 (13–210)). No eclosion of A. aegypti eggs at different concentrations studied was observed. The controleclodedin 35%. At concentration of 250 μg/mL, 93.3% of larvae remained in the second instar of development and at concentrations of 500, 750, and 1000 μg/mL the inhibitory effect was lower with percentages of 20%, 53.3%, and 46.6%, respectively. Morphological changes like disruption on the peritrophic envelope (PE), discontinued underlying epithelium, increased gut lumen, and segments with hypertrophic aspects were observed in anterior region of medium midgut of larvae of A. aegypti. The results showed repellent activity, specific embryotoxicity, and general growth retardation in A. aegypti by medium containing aqueous extract of I. suffruticosa leaves. PMID:21822443

  19. Two genes encoding midgut-specific maltase-like polypeptides from Anopheles gambiae.

    PubMed

    Zheng, L; Whang, L H; Kumar, V; Kafatos, F C

    1995-11-01

    Full-length cDNA clones of two genes have been isolated from the African malaria vector mosquito, Anopheles gambiae. These genes, designated Agm1 and Agm2, encode maltase-like polypeptides of 498 and 599 residues, respectively. Deduced amino acid sequences contain a putative signal peptide sequence and four potential glycosylation sites. Agm1 and Agm2 show highest similarities to the Mal1 gene from Aedes aegypti and three clustered maltase genes from Drosophila melanogaster. Both genes are located at position 46D, in the terminal division of the left arm of the third chromosome. Agm2 has very strict tissue and temporal specificity, being expressed exclusively in the adult midgut. The specificity of Agm1 is similar but appears slightly broader; transcripts of this gene are detected at a low level in the pupae, and occasionally in the adult carcass after removal of the midgut.

  20. Mod(mdg4) participates in hormonally regulated midgut programmed cell death during metamorphosis.

    PubMed

    Cai, Mei-Juan; Liu, Wen; He, Hong-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2012-12-01

    The insect midgut undergoes programmed cell death (PCD) during metamorphosis, but the molecular basis for this phenomenon has not been demonstrated. We report a mod(mdg4) protein [designated as mod(mdg4)1A] that is involved in hormonally regulated insect midgut PCD, from the lepidopteran Helicoverpa armigera. Mod(mdg4)1A is localized in the larval midgut and is highly expressed during metamorphosis. Knockdown of mod(mdg4)1a by feeding dsRNA to the larvae suppressed midgut PCD and delayed metamorphosis. The mechanism is that mod(mdg4)1a knockdown decreased the transcript levels of genes involved in PCD and metamorphosis, but increased the transcript level of inhibitor of apoptosis survivin. The transcript level of mod(mdg4)1a is independently upregulated by 20-hydroxyecdysone (20E) or juvenile hormone (JH) analog methoprene. Overlapped 20E and methoprene counteractively regulate the transcript level of mod(mdg4)1a. 20E upregulates the mod(mdg4)1a transcript level not through its nuclear receptor EcRB1. Methoprene upregulates the mod(mdg4)1a transcript level through the juvenile hormone candidate receptor Met. These findings indicate that mod(mdg4)1a participates in midgut PCD and metamorphosis by regulating the transcript levels of a network of genes via different pathways under 20E and JH regulation.

  1. Alterations in the Helicoverpa armigera Midgut Digestive Physiology after Ingestion of Pigeon Pea Inducible Leucine Aminopeptidase

    PubMed Central

    Lomate, Purushottam R.; Jadhav, Bhakti R.; Giri, Ashok P.; Hivrale, Vandana K.

    2013-01-01

    Jasmonate inducible plant leucine aminopeptidase (LAP) is proposed to serve as direct defense in the insect midgut. However, exact functions of inducible plant LAPs in the insect midgut remain to be estimated. In the present investigation, we report the direct defensive role of pigeon pea inducible LAP in the midgut of Helicoverpa armigera (Lepidoptera: Noctuidae) and responses of midgut soluble aminopeptidases and serine proteinases upon LAP ingestion. Larval growth and survival was significantly reduced on the diets supplemented with pigeon pea LAP. Aminopeptidase activities in larvae remain unaltered in presence or absence of inducible LAP in the diet. On the contrary, serine proteinase activities were significantly decreased in the larvae reared on pigeon pea LAP containing diet as compared to larvae fed on diet without LAP. Our data suggest that pigeon pea inducible LAP is responsible for the degradation of midgut serine proteinases upon ingestion. Reduction in the aminopeptidase activity with LpNA in the H. armigera larvae was compensated with an induction of aminopeptidase activity with ApNA. Our findings could be helpful to further dissect the roles of plant inducible LAPs in the direct plant defense against herbivory. PMID:24098675

  2. Alterations in the Helicoverpa armigera midgut digestive physiology after ingestion of pigeon pea inducible leucine aminopeptidase.

    PubMed

    Lomate, Purushottam R; Jadhav, Bhakti R; Giri, Ashok P; Hivrale, Vandana K

    2013-01-01

    Jasmonate inducible plant leucine aminopeptidase (LAP) is proposed to serve as direct defense in the insect midgut. However, exact functions of inducible plant LAPs in the insect midgut remain to be estimated. In the present investigation, we report the direct defensive role of pigeon pea inducible LAP in the midgut of Helicoverpa armigera (Lepidoptera: Noctuidae) and responses of midgut soluble aminopeptidases and serine proteinases upon LAP ingestion. Larval growth and survival was significantly reduced on the diets supplemented with pigeon pea LAP. Aminopeptidase activities in larvae remain unaltered in presence or absence of inducible LAP in the diet. On the contrary, serine proteinase activities were significantly decreased in the larvae reared on pigeon pea LAP containing diet as compared to larvae fed on diet without LAP. Our data suggest that pigeon pea inducible LAP is responsible for the degradation of midgut serine proteinases upon ingestion. Reduction in the aminopeptidase activity with LpNA in the H. armigera larvae was compensated with an induction of aminopeptidase activity with ApNA. Our findings could be helpful to further dissect the roles of plant inducible LAPs in the direct plant defense against herbivory.

  3. The cytological effect of ecdysterone on the midgut cells of the flesh-fly Sarcophaga bullata.

    PubMed

    Radford, S V; Misch, D W

    1971-06-01

    Larvae of the flesh-fly, Sarcophaga bullata, were injected with the synthetic moulting hormone ecdysterone or saline at the beginning of the third and final larval instar. One group was left untreated. The ecdysterone-injected larvae showed an increase in number of secondary lysosomes in the midgut epithelial cells similar to that observed at the onset of metamorphosis, an event which would normally occur about 48 hr later in these larvae.

  4. THE CYTOLOGICAL EFFECT OF ECDYSTERONE ON THE MIDGUT CELLS OF THE FLESH-FLY SARCOPHAGA BULLATA

    PubMed Central

    Radford, Sharon V.; Misch, Donald W.

    1971-01-01

    Larvae of the flesh-fly, Sarcophaga bullata, were injected with the synthetic moulting hormone ecdysterone or saline at the beginning of the third and final larval instar. One group was left untreated. The ecdysterone-injected larvae showed an increase in number of secondary lysosomes in the midgut epithelial cells similar to that observed at the onset of metamorphosis, an event which would normally occur about 48 hr later in these larvae. PMID:5092208

  5. Intestinal malrotation and midgut volvulus.

    PubMed

    Hamidi, Hidayatullah; Obaidy, Yalda; Maroof, Sahar

    2016-09-01

    A four-day-old boy presented with persistent bilious vomiting, bloody stained stool, and mild abdominal distension. Transabdominal ultrasound demonstrated a round soft-tissue mass-like structure in the right upper quadrant. With color Doppler ultrasound, the whirlpool sign was observed. Abdominal radiograph showed nonspecific findings. Upper gastrointestinal series revealed upper gastrointestinal tract obstruction at the level of distal duodenum. The diagnosis of intestinal malrotation with midgut volvulus was established and the treated surgically. Intestinal malrotation is congenital abnormal positioning of the bowel loops within the peritoneal cavity resulting in abnormal shortening of mesenteric root that is predisposed to midgut volvulus. Neonates and infants with persistent bilious vomiting should undergo diagnostic workup and preferably ultrasound as the first step. With classic sonographic appearance of whirlpool sign, even further imaging investigations is often not needed, and the surgeon should be alerted to plan surgery. PMID:27594965

  6. Morphological and genetic variability within Aedes aegypti in Niakhar, Senegal.

    PubMed

    Paupy, Christophe; Brengues, Cécile; Ndiath, Ousmane; Toty, Céline; Hervé, Jean-Pierre; Simard, Frédéric

    2010-05-01

    Aedes aegypti (Linné, 1762) is a major vector of arboviruses such as Yellow Fever, Dengue and Chikungunya. In Africa, where the species exhibits major variations in morphology, ecology, behavior and vector competence, two subspecies have been described: a light form, named Ae. aegypti aegypti (Aaa) with highly domestic and anthropophilic habits and a cosmotropical distribution; and a dark form, referred to as Ae. aegypti formosus (Aaf), which is endemic to Africa and thrives in sylvan environments. In East Africa, both forms were described to occur in sympatry whereas only Aaf was reported from Central/West Africa. However, recent findings suggest Aaa was also common in Senegal. Here, we report on a longitudinal survey of morphological and genetic variability of Ae. aegypti sampled in the rural environment of Niakhar, Senegal. In agreement with recent findings, most of specimens we analyzed were classified as Aaa suggesting typical Aaf was scarce in the studied area. Among Aaa, significant temporal variations in abdominal pale scales pattern were detected. Depending on the season and the nature of larval breeding places, the specimens (particularly females) tend to segregate in two main morphological groups. Microsatellite-based estimates of genetic differentiation did not provide any clear evidence that the two groups were genetically distinct. Overall, these results improve our understanding of the diversity of Ae. aegypti in West Africa, where data are crucially lacking.

  7. Aedes aegypti resistance to temephos in Argentina.

    PubMed

    Seccacini, Emilia; Lucia, Alejandro; Zerba, Eduardo; Licastro, Susana; Masuh, Hector

    2008-12-01

    Monitoring of resistance of Aedes aegypti to temephos was implemented in the provinces of Formosa and Misiones, Argentina, as a response to the need to improve the vigilance for the dengue vector in areas of high risk of dengue. Eggs collected in each locality were reared, and susceptibility to temephos was assayed using larval bioassays. A weak decrease in susceptibility of larvae to temephos was observed in Clorinda and Puerto Iguazú, indicating an incipient resistance with a resistance ratio of 3. No control failures have been observed yet, and this program should allow the early detection of a real problem in our country.

  8. Occurrence of Toxorhynchites guadeloupensis (Dyar Knab) in oviposition trap of Aedes aegypti (L.) (Diptera: Culicidae).

    PubMed

    Honório, Nildimar A; de Barros, Fábio S M; Tsouris, Pantelis; Rosa-Freitas, Maria G

    2007-01-01

    Toxorhynchites guadeloupensis (Dyar Knab), a poorly known mosquito species, was observed preying upon Aedes aegypti (L.) larvae, in an oviposition trap placed for routine dengue entomological surveillance, during 2003-2004 in the urban area of Boa Vista, Roraima, Brazil. This is the first report for Tx. guadeloupensis using Ae. aegypti oviposition traps as breeding places. This finding may have important consequences in the epidemiology and local dengue control since Ae. aegypti density is a basic variable in dengue prediction. Whether predation of Ae aegypti by Tx. guadeloupensis in the Amazon is of significance, is a question to be examined. Also, larval predation may be a cause for underestimation of the actual Ae aegypti numbers. Together these hypotheses need to be better investigated as they are directly related to dengue epidemiology, to the success of any outbreak prediction and surveillance program.

  9. Morphological alterations induced by boric acid and fipronil in the midgut of worker honeybee (Apis mellifera L.) larvae : Morphological alterations in the midgut of A. mellifera.

    PubMed

    da Silva Cruz, Aline; da Silva-Zacarin, Elaine C M; Bueno, Odair C; Malaspina, Osmar

    2010-04-01

    Morphological alterations, by means of histological and ultrastructural analysis, have been used to determine the effects of boric acid and fipronil on midgut tissues of honeybee worker, Apis mellifera L. larvae. In order to observe possible morphological alterations in the midgut, two groups of bioassays were performed. In the first one, the larvae were chronically treated with different concentrations of boric acid added to the food (1.0, 2.5 and 7.5 mg/g). In the second group, the larvae were fed with diets containing different concentrations of fipronil (0.1 and 1 microg/g) and compared with control groups without these chemical compounds. In the first bioassay, the larvae were collected on day 3 and in the second bioassay on day 4, when the mortality rate obtained in the toxicological bioassay was not very high. The larval midguts were removed and processed for morphological analyses using a light and transmission electron microscopy. We observed cytoplasmic vacuolizations, with the absence of autophagic vacuoles, and chromatinic compacting in most of the cells in the groups treated with pesticides. The morphological alterations were far greater in the larvae treated with boric acid than in the larvae treated with fipronil. Our data suggest that the midgut cell death observed was in response to boric acid and fipronil action. This study significantly improves the understanding of the toxicological effect of these insecticides from the ecotoxicological perspective.

  10. EFFICACY OF THAI NEEM OIL AGAINST AEDES AEGYPTI (L.) LARVAE.

    PubMed

    Silapanuntakul, Suthep; Keanjoom, Romnalin; Pandii, Wongdyan; Boonchuen, Supawadee; Sombatsiri, Kwanchai

    2016-05-01

    Trees with larvicidal activity may be found in Thailand. We conducted this study to evaluate the efficacy and length of efficacy of Thai neem (Azadirachta siamensis) oil emulsion and an alginate bead of Thai neem oil formulation against early fourth stage Aedes aegypti larvae using a dipping test. The Thai neem oil emulsion had significantly greater larvicidal activity than the alginate bead formulation at 12 to 60 hours post-exposure (p < 0.01). The Thai neem oil formulation resulted in 100% mortality among the early fourth stage Aedes aegypti larvae at 48 hours, while the alginate bead formulation resulted in 98% larval mortality at 84 hours and 100% mortality at 96 hours. The mean larval mortality using the Thai neem oil emulsion dropped to < 25% by 12 days and with the alginate beads dropped to < 25% by 15 days of exposure.

  11. EFFICACY OF THAI NEEM OIL AGAINST AEDES AEGYPTI (L.) LARVAE.

    PubMed

    Silapanuntakul, Suthep; Keanjoom, Romnalin; Pandii, Wongdyan; Boonchuen, Supawadee; Sombatsiri, Kwanchai

    2016-05-01

    Trees with larvicidal activity may be found in Thailand. We conducted this study to evaluate the efficacy and length of efficacy of Thai neem (Azadirachta siamensis) oil emulsion and an alginate bead of Thai neem oil formulation against early fourth stage Aedes aegypti larvae using a dipping test. The Thai neem oil emulsion had significantly greater larvicidal activity than the alginate bead formulation at 12 to 60 hours post-exposure (p < 0.01). The Thai neem oil formulation resulted in 100% mortality among the early fourth stage Aedes aegypti larvae at 48 hours, while the alginate bead formulation resulted in 98% larval mortality at 84 hours and 100% mortality at 96 hours. The mean larval mortality using the Thai neem oil emulsion dropped to < 25% by 12 days and with the alginate beads dropped to < 25% by 15 days of exposure. PMID:27405123

  12. Intraspecific Competition and Population Dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Paixão, C. A.; Charret, I. C.; Lima, R. R.

    2012-04-01

    We report computational simulations for the evolution of the population of the dengue vector, Aedes aegypti mosquitoes. The results suggest that controlling the mosquito population, on the basis of intraspecific competition at the larval stage, can be an efficient mechanism for controlling the spread of the epidemic. The results also show the presence of a kind of genetic evolution in vector population, which results mainly in increasing the average lifespan of individuals in adulthood.

  13. Midgut proteinases of Sitotroga cerealella (Oliver) (Lepidoptera:Gelechiidae): Characterization and relationship to resistance in cereals

    SciTech Connect

    Wu, Lan.

    1989-01-01

    Midgut proteinases are vital to the insects which digest ingested food in the midgut. Insect midgut proteinases, therefore, have been considered as possible targets for the control of insect pests. Proteinaceous proteinase inhibitors are very attractive for their potential use in developing insect resistant plant varieties via genetic engineering. Sitotroga cerealella is one of the major storage pests of cereals, and no antibiotic resistance in wheat against this insect has been identified to date. A series of diagnostic inhibitors, thiol-reducing agents and a metal-ion chelator were used in the identification of proteinases in crude extracts from S. cerealella larval midguts with both protein and ester substrates. The partial inhibition of proteolytic activity in crude midgut extract toward ({sup 3}H)-methemoglobin by pepstatin A suggested the presence of another proteinase which was sensitive to pepstatin A. The optimum pH range for the proteolytic activity, however, indicated that the major midgut proteinases were not carboxyl proteinases. Two proteinases were successfully purified by a combination of fractionation with ammonium sulfate, gel permeation and anion exchange chromatography. Characterization of the enzymes with the purified enzyme preparations confirmed that the two major proteinases were serine endoproteinases with trypsin-like and chymotrypsin-like specificities respectively. Bioassays were conducted using the artificial seeds to test naturally occurring proteinaceous proteinase inhibitors of potential value. Soybean trypsin inhibitor and the Bowman-Birk proteinase inhibitor had adverse effects on the development of the insect. A predictive model was constructed to evaluate effects of seed resistance in conjunction with other control methods on S. cerealella population dynamics.

  14. Seasonality and Locality Affect the Diversity of Anopheles gambiae and Anopheles coluzzii Midgut Microbiota from Ghana

    PubMed Central

    Gendrin, Mathilde; Pels, Nana Adjoa P.; Yeboah-Manu, Dorothy; Christophides, George K.; Wilson, Michael D.

    2016-01-01

    Symbiotic bacteria can have important implications in the development and competence of disease vectors. In Anopheles mosquitoes, the composition of the midgut microbiota is largely influenced by the larval breeding site, but the exact factors shaping this composition are currently unknown. Here, we examined whether the proximity to urban areas and seasons have an impact on the midgut microbial community of the two major malaria vectors in Africa, An. coluzzii and An. gambiae. Larvae and pupae were collected from selected habitats in two districts of Ghana during the dry and rainy season periods. The midgut microbiota of adults that emerged from these collections was determined by 454-pyrosequencing of the 16S ribosomal DNA. We show that in both mosquito species, Shewanellaceae constituted on average of 54% and 73% of the midgut microbiota from each site in the dry and rainy season, respectively. Enterobacteriaceae was found in comparatively low abundance below 1% in 22/30 samples in the dry season, and in 25/38 samples in the rainy season. Our data indicate that seasonality and locality significantly affect both the diversity of microbiota and the relative abundance of bacterial families with a positive impact of dry season and peri-urban settings. PMID:27322614

  15. Seasonality and Locality Affect the Diversity of Anopheles gambiae and Anopheles coluzzii Midgut Microbiota from Ghana.

    PubMed

    Akorli, Jewelna; Gendrin, Mathilde; Pels, Nana Adjoa P; Yeboah-Manu, Dorothy; Christophides, George K; Wilson, Michael D

    2016-01-01

    Symbiotic bacteria can have important implications in the development and competence of disease vectors. In Anopheles mosquitoes, the composition of the midgut microbiota is largely influenced by the larval breeding site, but the exact factors shaping this composition are currently unknown. Here, we examined whether the proximity to urban areas and seasons have an impact on the midgut microbial community of the two major malaria vectors in Africa, An. coluzzii and An. gambiae. Larvae and pupae were collected from selected habitats in two districts of Ghana during the dry and rainy season periods. The midgut microbiota of adults that emerged from these collections was determined by 454-pyrosequencing of the 16S ribosomal DNA. We show that in both mosquito species, Shewanellaceae constituted on average of 54% and 73% of the midgut microbiota from each site in the dry and rainy season, respectively. Enterobacteriaceae was found in comparatively low abundance below 1% in 22/30 samples in the dry season, and in 25/38 samples in the rainy season. Our data indicate that seasonality and locality significantly affect both the diversity of microbiota and the relative abundance of bacterial families with a positive impact of dry season and peri-urban settings.

  16. Seasonality and Locality Affect the Diversity of Anopheles gambiae and Anopheles coluzzii Midgut Microbiota from Ghana.

    PubMed

    Akorli, Jewelna; Gendrin, Mathilde; Pels, Nana Adjoa P; Yeboah-Manu, Dorothy; Christophides, George K; Wilson, Michael D

    2016-01-01

    Symbiotic bacteria can have important implications in the development and competence of disease vectors. In Anopheles mosquitoes, the composition of the midgut microbiota is largely influenced by the larval breeding site, but the exact factors shaping this composition are currently unknown. Here, we examined whether the proximity to urban areas and seasons have an impact on the midgut microbial community of the two major malaria vectors in Africa, An. coluzzii and An. gambiae. Larvae and pupae were collected from selected habitats in two districts of Ghana during the dry and rainy season periods. The midgut microbiota of adults that emerged from these collections was determined by 454-pyrosequencing of the 16S ribosomal DNA. We show that in both mosquito species, Shewanellaceae constituted on average of 54% and 73% of the midgut microbiota from each site in the dry and rainy season, respectively. Enterobacteriaceae was found in comparatively low abundance below 1% in 22/30 samples in the dry season, and in 25/38 samples in the rainy season. Our data indicate that seasonality and locality significantly affect both the diversity of microbiota and the relative abundance of bacterial families with a positive impact of dry season and peri-urban settings. PMID:27322614

  17. Midgut epithelium in molting silkworm: A fine balance among cell growth, differentiation, and survival.

    PubMed

    Franzetti, Eleonora; Casartelli, Morena; D'Antona, Paola; Montali, Aurora; Romanelli, Davide; Cappellozza, Silvia; Caccia, Silvia; Grimaldi, Annalisa; de Eguileor, Magda; Tettamanti, Gianluca

    2016-07-01

    The midgut of insects has attracted great attention as a system for studying intestinal stem cells (ISCs) as well as cell death-related processes, such as apoptosis and autophagy. Among insects, Lepidoptera represent a good model to analyze these cells and processes. In particular, larva-larva molting is an interesting developmental phase since the larva must deal with nutrient starvation and its organs are subjected to rearrangements due to proliferation and differentiation events. Several studies have analyzed ISCs in vitro and characterized key factors involved in their division and differentiation during molt. However, in vivo studies performed during larva-larva transition on these cells, and on the whole midgut epithelium, are fragmentary. In the present study, we analyzed the larval midgut epithelium of the silkworm, Bombyx mori, during larva-larva molting, focusing our attention on ISCs. Moreover, we investigated the metabolic changes that occur in the epithelium and evaluated the intervention of autophagy. Our data on ISCs proliferation and differentiation, autophagy activation, and metabolic and functional activities of the midgut cells shed light on the complexity of this organ during the molting phase. PMID:27349418

  18. Responses of midgut amylases of Helicoverpa armigera to feeding on various host plants.

    PubMed

    Kotkar, Hemlata M; Sarate, Priya J; Tamhane, Vaijayanti A; Gupta, Vidya S; Giri, Ashok P

    2009-08-01

    Midgut digestive amylases and proteinases of Helicoverpa armigera, a polyphagous and devastating insect pest of economic importance have been studied. We also identified the potential of a sorghum amylase inhibitor against H. armigera midgut amylase. Amylase activities were detected in all the larval instars, pupae, moths and eggs; early instars had lower amylase levels which steadily increased up to the sixth larval instar. Qualitative and quantitative differences in midgut amylases of H. armigera upon feeding on natural and artificial diets were evident. Natural diets were categorized as one or more members of legumes, vegetables, flowers and cereals belonging to different plant families. Amylase activity and isoform patterns varied depending on host plant and/or artificial diet. Artificial diet-fed H. armigera larvae had comparatively high amylase activity and several unique amylase isoforms. Correlation of amylase and proteinase activities of H. armigera with the protein and carbohydrate content of various diets suggested that H. armigera regulates the levels of these digestive enzymes in response to macromolecular composition of the diet. These adjustments in the digestive enzymes of H. armigera may be to obtain better nourishment from the diet and avoid toxicity due to nutritional imbalance. H. armigera, a generalist feeder experiences a great degree of nutritional heterogeneity in its diet. An investigation of the differences in enzyme levels in response to macronutrient balance and imbalance highlight their importance in insect nutrition.

  19. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus.

    PubMed

    Crava, Cristina M; Jakubowska, Agata K; Escriche, Baltasar; Herrero, Salvador; Bel, Yolanda

    2015-01-01

    Antimicrobial peptides (AMPs) and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae), a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt) or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV). We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity.

  20. Dissimilar Regulation of Antimicrobial Proteins in the Midgut of Spodoptera exigua Larvae Challenged with Bacillus thuringiensis Toxins or Baculovirus

    PubMed Central

    Crava, Cristina M.; Jakubowska, Agata K.; Escriche, Baltasar; Herrero, Salvador; Bel, Yolanda

    2015-01-01

    Antimicrobial peptides (AMPs) and lysozymes are the main effectors of the insect immune system, and they are involved in both local and systemic responses. Among local responses, midgut immune reaction plays an important role in fighting pathogens that reach the insect body through the oral route, as do many microorganisms used in pest control. Under this point of view, understanding how insects defend themselves locally during the first phases of infections caused by food-borne pathogens is important to further improve microbial control strategies. In the present study, we analyzed the transcriptional response of AMPs and lysozymes in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae), a polyphagous pest that is commonly controlled by products based on Bacillus thuringiensis (Bt) or baculovirus. First, we comprehensively characterized the transcripts encoding AMPs and lysozymes expressed in S. exigua larval midgut, identifying 35 transcripts that represent the S. exigua arsenal against microbial infection. Secondly, we analyzed their expression in the midgut after ingestion of sub-lethal doses of two different pore-forming B. thuringiensis toxins, Cry1Ca and Vip3Aa, and the S. exigua nucleopolyhedrovirus (SeMNPV). We observed that both Bt toxins triggered a similar, wide and in some cases high transcriptional activation of genes encoding AMPs and lysozymes, which was not reflected in the activation of the classical systemic immune-marker phenoloxidase in hemolymph. Baculovirus ingestion resulted in the opposed reaction: Almost all transcripts coding for AMPs and lysozymes were down-regulated or not induced 96 hours post infection. Our results shed light on midgut response to different virulence factors or pathogens used nowadays as microbial control agents and point out the importance of the midgut immune response contribution to the larval immunity. PMID:25993013

  1. Ultrastructural analysis of midgut cells from Culex quinquefasciatus (Diptera: Culicidae) larvae resistant to Bacillus sphaericus.

    PubMed

    de Melo, Janaina Viana; Vasconcelos, Romero Henrique Teixeira; Furtado, André Freire; Peixoto, Christina Alves; Silva-Filha, Maria Helena Neves Lobo

    2008-12-01

    The larvicidal action of the entomopathogen Bacillus sphaericus towards Culex quinquefasciatus is due to the binary (Bin) toxin present in crystals, which are produced during bacterial sporulation. The Bin toxin needs to recognize and bind specifically to a single class of receptors, named Cqm1, which are 60-kDa alpha-glucosidases attached to the apical membrane of midgut cells by a glycosylphosphatidylinositol anchor. C. quinquefasciatus resistance to B. sphaericus has been often associated with the absence of the alpha-glucosidase Cqm1 in larvae midgut microvilli. In this work, we aimed to investigate, at the ultrastructural level, the midgut cells from C. quinquefasciatus larvae whose resistance relies on the lack of the Cqm1 receptor. The morphological analysis showed that midgut columnar cells from the resistant larvae are characterized by a pronounced production of lipid inclusions, throughout the 4th instar. At the end of this stage, resistant larvae had an increased size and number of these inclusions in the midgut cells, while only a small number were observed in the cells from susceptible larvae. The morphological differences in the midgut cells of resistant larvae found in this work suggested that the lack of the Cqm1 receptor, which also has a physiological role as being an alpha-glucosidase, can be related to changes in the cell metabolism. The ultrastructural effects of Bin toxin on midgut epithelial cells from susceptible and resistant larvae were also investigated. The cytopathological alterations observed in susceptible larvae treated with a lethal concentration of toxin included breakdown of the endoplasmic reticulum, mitochondrial swelling, microvillar disruption and vacuolization. Some effects were observed in cells from resistant larvae, although those alterations did not lead to larval death, indicating that the receptor Cqm1 is essential to mediate the larvicidal action of the toxin. This is the first ultrastructural study to show differences

  2. Amino acids trigger down-regulation of superoxide via TORC pathway in the midgut of Rhodnius prolixus

    PubMed Central

    Gandara, Ana Caroline P.; Oliveira, José Henrique M.; Nunes, Rodrigo D.; Goncalves, Renata L.S.; Dias, Felipe A.; Hecht, Fabio; Fernandes, Denise C.; Genta, Fernando A.; Laurindo, Francisco R.M.; Oliveira, Marcus F.; Oliveira, Pedro L.

    2016-01-01

    Sensing incoming nutrients is an important and critical event for intestinal cells to sustain life of the whole organism. The TORC is a major protein complex involved in monitoring the nutritional status and is activated by elevated amino acid concentrations. An important feature of haematophagy is that huge amounts of blood are ingested in a single meal, which results in the release of large quantities of amino acids, together with the haemoglobin prosthetic group, haem, which decomposes hydroperoxides and propagates oxygen-derived free radicals. Our previous studies demonstrated that reactive oxygen species (ROS) levels were diminished in the mitochondria and midgut of the Dengue fever mosquito, Aedes aegypti, immediately after a blood meal. We proposed that this mechanism serves to avoid oxidative damage that would otherwise be induced by haem following a blood meal. Studies also performed in mosquitoes have shown that blood or amino acids controls protein synthesis through TORC activation. It was already proposed, in different models, a link between ROS and TOR, however, little is known about TOR signalling in insect midgut nor about the involvement of ROS in this pathway. Here, we studied the effect of a blood meal on ROS production in the midgut of Rhodnius prolixus. We observed that blood meal amino acids decreased ROS levels in the R. prolixus midgut immediately after feeding, via lowering mitochondrial superoxide production and involving the amino acid-sensing TORC pathway. PMID:26945025

  3. Shifting Patterns of Aedes aegypti Fine Scale Spatial Clustering in Iquitos, Peru

    PubMed Central

    LaCon, Genevieve; Morrison, Amy C.; Astete, Helvio; Stoddard, Steven T.; Paz-Soldan, Valerie A.; Elder, John P.; Halsey, Eric S.; Scott, Thomas W.; Kitron, Uriel; Vazquez-Prokopec, Gonzalo M.

    2014-01-01

    Background Empiric evidence shows that Aedes aegypti abundance is spatially heterogeneous and that some areas and larval habitats produce more mosquitoes than others. There is a knowledge gap, however, with regards to the temporal persistence of such Ae. aegypti abundance hotspots. In this study, we used a longitudinal entomologic dataset from the city of Iquitos, Peru, to (1) quantify the spatial clustering patterns of adult Ae. aegypti and pupae counts per house, (2) determine overlap between clusters, (3) quantify the temporal stability of clusters over nine entomologic surveys spaced four months apart, and (4) quantify the extent of clustering at the household and neighborhood levels. Methodologies/Principal Findings Data from 13,662 household entomological visits performed in two Iquitos neighborhoods differing in Ae. aegypti abundance and dengue virus transmission was analyzed using global and local spatial statistics. The location and extent of Ae. aegypti pupae and adult hotspots (i.e., small groups of houses with significantly [p<0.05] high mosquito abundance) were calculated for each of the 9 entomologic surveys. The extent of clustering was used to quantify the probability of finding spatially correlated populations. Our analyses indicate that Ae. aegypti distribution was highly focal (most clusters do not extend beyond 30 meters) and that hotspots of high vector abundance were common on every survey date, but they were temporally unstable over the period of study. Conclusions/Significance Our findings have implications for understanding Ae. aegypti distribution and for the design of surveillance and control activities relying on household-level data. In settings like Iquitos, where there is a relatively low percentage of Ae. aegypti in permanent water-holding containers, identifying and targeting key premises will be significantly challenged by shifting hotspots of Ae. aegypti infestation. Focusing efforts in large geographic areas with historically

  4. Microevolution of Aedes aegypti

    PubMed Central

    Louise, Caroline; Vidal, Paloma Oliveira; Suesdek, Lincoln

    2015-01-01

    Scientific research into the epidemiology of dengue frequently focuses on the microevolution and dispersion of the mosquito Aedes aegypti. One of the world’s largest urban agglomerations infested by Ae. aegypti is the Brazilian megalopolis of Sao Paulo, where >26,900 cases of dengue were reported until June 2015. Unfortunately, the dynamics of the genetic variability of Ae. aegypti in the Sao Paulo area have not been well studied. To reduce this knowledge gap, we assessed the morphogenetic variability of a population of Ae. aegypti from a densely urbanised neighbourhood of Sao Paulo. We tested if allelic patterns could vary over a short term and if wing shape could be a predictor of the genetic variation. Over a period of 14 months, we examined the variation of genetic (microsatellites loci) and morphological (wing geometry) markers in Ae. aegypti. Polymorphisms were detected, as revealed by the variability of 20 microsatellite loci (115 alleles combined; overall Fst = 0.0358) and 18 wing landmarks (quantitative estimator Qst = 0.4732). These levels of polymorphism are higher than typically expected to an exotic species. Allelic frequencies of the loci changed over time and temporal variation in the wing shape was even more pronounced, permitting high reclassification levels of chronological samples. In spite of the fact that both markers underwent temporal variation, no correlation was detected between their dynamics. We concluded that microevolution was detected despite the short observational period, but the intensities of change of the markers were discrepant. Wing shape failed from predicting allelic temporal variation. Possibly, natural selection (Qst>Fst) or variance of expressivity of wing phenotype are involved in this discrepancy. Other possibly influential factors on microevolution of Ae. aegypti are worth searching. Additionally, the implications of the rapid evolution and high polymorphism of this mosquito vector on the efficacy of control methods

  5. Microevolution of Aedes aegypti.

    PubMed

    Louise, Caroline; Vidal, Paloma Oliveira; Suesdek, Lincoln

    2015-01-01

    Scientific research into the epidemiology of dengue frequently focuses on the microevolution and dispersion of the mosquito Aedes aegypti. One of the world's largest urban agglomerations infested by Ae. aegypti is the Brazilian megalopolis of Sao Paulo, where >26,900 cases of dengue were reported until June 2015. Unfortunately, the dynamics of the genetic variability of Ae. aegypti in the Sao Paulo area have not been well studied. To reduce this knowledge gap, we assessed the morphogenetic variability of a population of Ae. aegypti from a densely urbanised neighbourhood of Sao Paulo. We tested if allelic patterns could vary over a short term and if wing shape could be a predictor of the genetic variation. Over a period of 14 months, we examined the variation of genetic (microsatellites loci) and morphological (wing geometry) markers in Ae. aegypti. Polymorphisms were detected, as revealed by the variability of 20 microsatellite loci (115 alleles combined; overall Fst = 0.0358) and 18 wing landmarks (quantitative estimator Qst = 0.4732). These levels of polymorphism are higher than typically expected to an exotic species. Allelic frequencies of the loci changed over time and temporal variation in the wing shape was even more pronounced, permitting high reclassification levels of chronological samples. In spite of the fact that both markers underwent temporal variation, no correlation was detected between their dynamics. We concluded that microevolution was detected despite the short observational period, but the intensities of change of the markers were discrepant. Wing shape failed from predicting allelic temporal variation. Possibly, natural selection (Qst>Fst) or variance of expressivity of wing phenotype are involved in this discrepancy. Other possibly influential factors on microevolution of Ae. aegypti are worth searching. Additionally, the implications of the rapid evolution and high polymorphism of this mosquito vector on the efficacy of control methods have

  6. Cytotoxic effects of neem oil in the midgut of the predator Ceraeochrysa claveri.

    PubMed

    Scudeler, Elton Luiz; Garcia, Ana Silvia Gimenes; Padovani, Carlos Roberto; Pinheiro, Patricia Fernanda Felipe; dos Santos, Daniela Carvalho

    2016-01-01

    Studies of morphological and ultrastructural alterations in target organs have been useful for evaluating the sublethal effects of biopesticides regarded as safe for non-target organisms in ecotoxicological analyses. One of the most widely used biopesticides is neem oil, and its safety and compatibility with natural enemies have been further clarified through bioassays performed to analyze the effects of indirect exposure by the intake of poisoned prey. Thus, this study examined the cellular response of midgut epithelial cells of the adult lacewing, Ceraeochrysa claveri, to neem oil exposure via intake of neem oil-contaminated prey during the larval stage. C. claveri larvae were fed Diatraea saccharalis eggs treated with neem oil at concentrations of 0.5%, 1% and 2% throughout the larval stage. The adult females obtained from these treatments were used at two ages (newly emerged and at the start of oviposition) in morphological and ultrastructural analyses. Neem oil was found to cause pronounced cytotoxic effects in the adult midgut, such as cell dilation, emission of cytoplasmic protrusions, cell lysis, loss of integrity of the cell cortex, dilation of cisternae of the rough endoplasmic reticulum, swollen mitochondria, vesiculated appearance of the Golgi complex and dilated invaginations of the basal labyrinth. Epithelial cells responded to those injuries with various cytoprotective and detoxification mechanisms, including increases in cell proliferation, the number of calcium-containing cytoplasmic granules, and HSP 70 expression, autophagic processes and the development of smooth endoplasmic reticulum, but these mechanisms were insufficient for recovery from all of the cellular damage to the midgut. This study demonstrates that neem oil exposure impairs the midgut by causing sublethal effects that may affect the physiological functions of this organ, indicating the importance of studies of different life stages of this species and similar species to evaluate the

  7. Cytotoxic effects of neem oil in the midgut of the predator Ceraeochrysa claveri.

    PubMed

    Scudeler, Elton Luiz; Garcia, Ana Silvia Gimenes; Padovani, Carlos Roberto; Pinheiro, Patricia Fernanda Felipe; dos Santos, Daniela Carvalho

    2016-01-01

    Studies of morphological and ultrastructural alterations in target organs have been useful for evaluating the sublethal effects of biopesticides regarded as safe for non-target organisms in ecotoxicological analyses. One of the most widely used biopesticides is neem oil, and its safety and compatibility with natural enemies have been further clarified through bioassays performed to analyze the effects of indirect exposure by the intake of poisoned prey. Thus, this study examined the cellular response of midgut epithelial cells of the adult lacewing, Ceraeochrysa claveri, to neem oil exposure via intake of neem oil-contaminated prey during the larval stage. C. claveri larvae were fed Diatraea saccharalis eggs treated with neem oil at concentrations of 0.5%, 1% and 2% throughout the larval stage. The adult females obtained from these treatments were used at two ages (newly emerged and at the start of oviposition) in morphological and ultrastructural analyses. Neem oil was found to cause pronounced cytotoxic effects in the adult midgut, such as cell dilation, emission of cytoplasmic protrusions, cell lysis, loss of integrity of the cell cortex, dilation of cisternae of the rough endoplasmic reticulum, swollen mitochondria, vesiculated appearance of the Golgi complex and dilated invaginations of the basal labyrinth. Epithelial cells responded to those injuries with various cytoprotective and detoxification mechanisms, including increases in cell proliferation, the number of calcium-containing cytoplasmic granules, and HSP 70 expression, autophagic processes and the development of smooth endoplasmic reticulum, but these mechanisms were insufficient for recovery from all of the cellular damage to the midgut. This study demonstrates that neem oil exposure impairs the midgut by causing sublethal effects that may affect the physiological functions of this organ, indicating the importance of studies of different life stages of this species and similar species to evaluate the

  8. Aedes aegypti (L.) and Aedes albopictus (Skuse) in Singapore City. 1. Distribution and density.

    PubMed

    Chan, Y C; Chan, K L; Ho, B C

    1971-01-01

    The distribution and density of Ae. aegypti and Ae. albopictus in Singapore were assessed from extensive larval surveys carried out from 1966 to 1968 to evaluate their respective roles in the epidemiology of dengue haemorrhagic fever and to study their ecology in the urban areas. Ten urban areas where the majority of dengue haemorrhagic fever cases occurred were surveyed.The results showed that both species were common in the city, with Ae. aegypti being the dominant species. The distribution of Ae. aegypti was more uniform and related to the prevailing housing types and conditions. Its premise index was highest in slum houses, intermediate in shop houses, and lowest in multistorey flats. Ae. albopictus, on the other hand, did not seem to be related to the prevailing housing type in its distribution but tended to be more widespread in areas with open spaces.The larval density index (the average number of larvae per housing unit) was higher for Ae. aegypti than for Ae. albopictus, in agreement with the relative densities shown by their premise indices. The larval density index correlated well with the premise index and correlated best with the infested-receptacle index. For practical purposes, the most suitable, convenient, and reliable measure of density of Ae. aegypti population seems to be the infested-receptacle index.An attempt was made to estimate the rate of dispersal of Ae. aegypti from a stable population to an adjacent area of multistorey flats. The rate of dispersal, estimated from the premise index and the larval density index, was approximately 2% per year of the "donor" population.

  9. Composition of the Spruce Budworm (Choristoneura fumiferana) Midgut Microbiota as Affected by Rearing Conditions.

    PubMed

    Landry, Mathieu; Comeau, André M; Derome, Nicolas; Cusson, Michel; Levesque, Roger C

    2015-01-01

    The eastern spruce budworm (Choristoneura fumiferana) is one of the most destructive forest insect pests in Canada. Little is known about its intestinal microbiota, which could play a role in digestion, immune protection, communication and/or development. The present study was designed to provide a first characterization of the effects of rearing conditions on the taxonomic diversity and structure of the C. fumiferana midgut microbiota, using a culture-independent approach. Three diets and insect sources were examined: larvae from a laboratory colony reared on a synthetic diet and field-collected larvae reared on balsam fir or black spruce foliage. Bacterial DNA from the larval midguts was extracted to amplify and sequence the V6-V8 region of the 16S rRNA gene, using the Roche 454 GS-FLX technology. Our results showed a dominance of Proteobacteria, mainly Pseudomonas spp., in the spruce budworm midgut, irrespective of treatment group. Taxonomic diversity of the midgut microbiota was greater for larvae reared on synthetic diet than for those collected and reared on host plants, a difference that is likely accounted for by several factors. A greater proportion of bacteria from the phylum Bacteroidetes in insects fed artificial diet constituted the main difference between this group and those reared on foliage; within the phylum Proteobacteria, the presence of the genus Bradyrhizobium was also unique to insects reared on artificial diet. Strikingly, a Bray-Curtis analysis showed important differences in microbial diversity among the treatment groups, pointing to the importance of diet and environment in defining the spruce budworm midgut microbiota. PMID:26636571

  10. Composition of the Spruce Budworm (Choristoneura fumiferana) Midgut Microbiota as Affected by Rearing Conditions

    PubMed Central

    Landry, Mathieu; Comeau, André M.; Derome, Nicolas; Cusson, Michel; Levesque, Roger C.

    2015-01-01

    The eastern spruce budworm (Choristoneura fumiferana) is one of the most destructive forest insect pests in Canada. Little is known about its intestinal microbiota, which could play a role in digestion, immune protection, communication and/or development. The present study was designed to provide a first characterization of the effects of rearing conditions on the taxonomic diversity and structure of the C. fumiferana midgut microbiota, using a culture-independent approach. Three diets and insect sources were examined: larvae from a laboratory colony reared on a synthetic diet and field-collected larvae reared on balsam fir or black spruce foliage. Bacterial DNA from the larval midguts was extracted to amplify and sequence the V6-V8 region of the 16S rRNA gene, using the Roche 454 GS-FLX technology. Our results showed a dominance of Proteobacteria, mainly Pseudomonas spp., in the spruce budworm midgut, irrespective of treatment group. Taxonomic diversity of the midgut microbiota was greater for larvae reared on synthetic diet than for those collected and reared on host plants, a difference that is likely accounted for by several factors. A greater proportion of bacteria from the phylum Bacteroidetes in insects fed artificial diet constituted the main difference between this group and those reared on foliage; within the phylum Proteobacteria, the presence of the genus Bradyrhizobium was also unique to insects reared on artificial diet. Strikingly, a Bray-Curtis analysis showed important differences in microbial diversity among the treatment groups, pointing to the importance of diet and environment in defining the spruce budworm midgut microbiota. PMID:26636571

  11. Infection pattern and transmission potential of chikungunya virus in two New World laboratory-adapted Aedes aegypti strains

    PubMed Central

    Dong, Shengzhang; Kantor, Asher M.; Lin, Jingyi; Passarelli, A. Lorena; Clem, Rollie J.; Franz, Alexander W. E.

    2016-01-01

    Chikungunya virus (CHIKV) is an emerging mosquito-borne virus belonging to the Togaviridae, which is transmitted to humans by Aedes aegypti and Ae. albopictus. We describe the infection pattern of CHIKV in two New World Ae. aegypti strains, HWE and ORL. Both mosquito strains were susceptible to the virus but showed different infection patterns in midguts and salivary glands. Even though acquisition of a bloodmeal showed moderate levels of apoptosis in midgut tissue, there was no obvious additional CHIKV-induced apoptosis detectable during midgut infection. Analysis of expression of apoptosis-related genes suggested that CHIKV infection dampens rather than promotes apoptosis in the mosquito midgut. In both mosquito strains, the virus was present in saliva within two days post-oral infection. HWE and ORL mosquitoes exhibited no salivary gland infection barrier; however, only 60% (HWE) to 65% (ORL) of the females had released the virus in their saliva at one week post-oral acquisition, suggesting a salivary gland escape barrier. CHIKV induced an apoptotic response in salivary glands of HWE and ORL mosquitoes, demonstrating that the virus caused pathology in its natural vector. PMID:27102548

  12. Determination of juvenile hormone titers by means of LC-MS/MS/MS and a juvenile hormone-responsive Gal4/UAS system in Aedes aegypti mosquitoes.

    PubMed

    Zhao, Bo; Hou, Yuan; Wang, Jianjun; Kokoza, Vladimir A; Saha, Tusar T; Wang, Xue-Li; Lin, Ling; Zou, Zhen; Raikhel, Alexander S

    2016-10-01

    In anautogenous mosquitoes, juvenile hormone III (JH) plays an essential role in female post-eclosion (PE) development, preparing them for subsequent blood feeding and egg growth. We re-examined the JH titer during the reproductive cycle of female Aedes aegypti mosquitoes. Using liquid chromatography coupled with triple tandem mass spectrometry (LC-MS/MS/MS), we have shown that it reaches its peak at 48-54 h PE in the female hemolymph and at 72 h PE in whole body extracts. This method represents an effective assay for determination of JH titers. The 2.1-kb 5' promoter region of the Early Trypsin (ET) gene, which is specifically expressed in the female midgut under the control of JH during the PE phase, was utilized to genetically engineer the Ae. aegypti mosquito line with the ET-Gal4 activator. We then established the ET-GAL4>UAS-enhanced green fluorescent protein (EGFP) system in Ae. aegypti. In ET-Gal4>UAS-EGFP female mosquitoes, the intensity of the midgut-specific EGFP signal was observed to correspond to the ET gene transcript level and follow the JH titer during the PE phase. The EGFP signal and the EGFP transcript level were significantly diminished in midguts of transgenic female mosquitoes after RNA interference depletion of the JH receptor Methoprene-tolerant (Met), providing evidence of the control of ET gene expression by Met. Topical JH application caused premature enhancement of the EGFP signal and the EGFP transcript level in midguts of newly eclosed ET-Gal4>UAS-EGFP female mosquitoes, in which endogenous JH titer is still low. Hence, this novel ET-Gal4>UAS system permits JH-dependent gene overexpression in the midgut of Ae. aegypti female mosquitoes prior to a blood meal. PMID:27530057

  13. Oral Susceptibility of Singapore Aedes (Stegomyia) aegypti (Linnaeus) to Zika Virus

    PubMed Central

    Ng, Lee Ching; Tan, Cheong Huat

    2012-01-01

    Background Zika virus (ZIKV) is a little known flavivirus that caused a major outbreak in 2007, in the South-western Pacific Island of Yap. It causes dengue-like syndromes but with milder symptoms. In Africa, where it was first isolated, ZIKV is mainly transmitted by sylvatic Aedes mosquitoes. The virus has also been isolated from Ae. aegypti and it is considered to be the vector involved in the urban transmission of the virus. Transmission of the virus by an African strain of Ae. aegypti has also been demonstrated under laboratory conditions. The aim of the present study is to describe the oral susceptibility of a Singapore strain of Ae. aegypti to ZIKV, under conditions that simulate local climate. Methodology/Principal Findings To assess the receptivity of Singapore's Ae. aegypti to the virus, we orally exposed a local mosquito strain to a Ugandan strain of ZIKV. Upon exposure, fully engorged mosquitoes were maintained in an environmental chamber set at 29°C and 70–75% RH. Eight mosquitoes were then sampled daily from day 1 to day 7, and subsequently on days 10 and 14 post exposure (pe). The virus titer of the midgut and salivary glands of each mosquito were determined using a tissue culture infectious dose50 (TCID50) assay. High midgut infection and salivary gland dissemination rates were observed. By day 5 after the infectious blood meal, ZIKV was found in the salivary glands of more than half of the mosquitoes tested (62%); and by day 10, all mosquitoes were potentially infective. Conclusions/Significance This study showed that Singapore's urban Ae. aegypti are susceptible and are potentially capable of transmitting ZIKV. The virus could be established in Singapore should it be introduced. Nevertheless, Singapore's current dengue control strategy is applicable to control ZIKV. PMID:22953014

  14. Gene Flow, Subspecies Composition, and Dengue Virus-2 Susceptibility among Aedes aegypti Collections in Senegal

    PubMed Central

    Sylla, Massamba; Bosio, Christopher; Urdaneta-Marquez, Ludmel; Ndiaye, Mady; Black, William C.

    2009-01-01

    collections, the disseminated infection rate (DIR) was 73.9% with a midgut infection barrier (MIB) rate of 6.8%, and a midgut escape barrier (MEB) rate of 19.3%, while among pure Aaf collections, DIR = 34.2%, MIB rate = 7.4%, and MEB rate = 58.4%. Allele and genotype frequencies were analyzed at 11 nuclear single nucleotide polymorphism (SNP) loci using allele specific PCR and melting curve analysis. In agreement with a published isozyme gene flow study in Senegal, only a small and statistically insignificant percentage of the variance in allele frequencies was associated with subspecies. Conclusions These results add to our understanding of the global phylogeny of Aedes aegypti s.l., suggesting that West African Aaa and Aaf are monophyletic and that Aaa evolved in West Africa from an Aaf ancestor. PMID:19365540

  15. Larval Temperature-Food Effects on Adult Mosquito Infection and Vertical Transmission of Dengue-1 Virus.

    PubMed

    Buckner, Eva A; Alto, Barry W; Lounibos, L Philip

    2016-01-01

    Temperature-food interactions in the larval environment can affect life history and population growth of container mosquitoes Aedes aegypti (L.) and Aedes albopictus Skuse, the primary vectors of chikungunya and dengue viruses. We used Ae. aegypti, Ae. albopictus, and dengue-1 virus (DENV-1) from Florida to investigate whether larval rearing temperature can alter the effects of larval food levels on Ae. aegypti and Ae. albopictus life history and DENV-1 infection and vertical transmission. Although we found no effect of larval treatments on survivorship to adulthood, DENV-1 titer, or DENV-1 vertical transmission, rates of vertical transmission up to 16-24% were observed in Ae. albopictus and Ae. aegypti, which may contribute to maintenance of this virus in nature. Larval treatments had no effect on number of progeny and DENV-1 infection in Ae. aegypti, but the interaction between temperature and food affected number of progeny and DENV-1 infection of the female Ae. albopictus parent. The cooler temperature (24°C) yielded the most progeny and this effect was accentuated by high food relative to the other conditions. Low and high food led to the highest (∼90%) and lowest (∼65%) parental infection at the cooler temperature, respectively, whereas intermediate infection rates (∼75-80%) were observed for all food conditions at the elevated temperature. These results suggest that temperature and food availability have minimal influence on rate of vertical transmission and a stronger influence on adults of Ae. albopictus than of Ae. aegypti, which could have consequences for dengue virus epidemiology. PMID:26489999

  16. Carbonic anhydrases and anion transport in mosquito midgut pH regulation

    PubMed Central

    Linser, Paul J.; Smith, Kristin E.; Seron, Terri J.; Neira Oviedo, Marco

    2009-01-01

    Summary Mosquito larvae use a digestive strategy that is relatively rare in nature. The anterior half of the larval mosquito midgut has a luminal pH that ranges between 10.5 and 11.5. Most other organisms, both large and small, initiate digestion in an acid medium. The relative uniqueness of the highly alkaline digestive strategy has been a long-standing research focus in larval lepidopterans. More recently, the disease vector potential of mosquitoes has fueled specific interest in larval mosquito biology and the alkaline digestive environment in the midgut. The probable principle anion influencing the highly alkaline gut lumen is bicarbonate/carbonate. Bicarbonate/carbonate is regulated at least in part by the activity of carbonic anhydrases. Hence, we have focused attention on the carbonic anhydrases of the mosquito larva. Anopheles gambiae, the major malaria mosquito of Africa, is an organism with a published genome which has facilitated molecular analyses of the 12 carbonic anhydrase genes annotated for this mosquito. Microarray expression analyses, tissue-specific quantitative RT-PCR, and antibody localization have been used to generate a picture of carbonic anhydrase distribution in the larval mosquito. Cytoplasmic, GPI-linked extracellular membrane-bound and soluble extracellular carbonic anhydrases have been located in the midgut and hindgut. The distribution of the enzymes is consistent with an anion regulatory system in which carbonic anhydrases provide a continuous source of bicarbonate/carbonate from the intracellular compartments of certain epithelial cells to the ectoperitrophic space between the epithelial cells and the acellular membrane separating the food bolus from the gut cells and finally into the gut lumen. Carbonic anhydrase in specialized cells of the hindgut (rectum) probably plays a final role in excretion of bicarbonate/carbonate into the aquatic environment of the larva. Detection and characterization of classic anion exchangers of the

  17. Environmental conditions in water storage drums and influences on Aedes aegypti in Trinidad, West Indies.

    PubMed

    Hemme, Ryan R; Tank, Jennifer L; Chadee, Dave D; Severson, David W

    2009-10-01

    Water storage drums are often a primary breeding site for Aedes aegypti in developing countries. Habitat characteristics can impact both adult and larval fitness and survival, which may potentially influence arbovirus transmission. Our objective was to compare fundamental environmental differences in water drums based on the presence or absence of larvae in Trinidad. Drums were categorized according to the larval status, and if the drum was constructed of steel or plastic. Water samples were analyzed for ammonium, nitrate, and soluble reactive phosphorus (SRP). Continuous surface water temperatures were also recorded. Nutrient concentrations were considerably lower than those reported for other container breeding mosquitoes. No nutrient measured differed in concentration between drums positive compared to those that were negative for the presence of A. aegypti larvae. Levels of SRP and ammonium in steel drums were significantly lower than in plastic water drums. Both maximum and minimum surface temperatures were significantly lower in drums positive for the presence of larvae than in drums without larvae. Water temperatures in March and May were warmer than during October sampling periods. Larval presence is likely dependent upon the interaction among multiple biotic and abiotic factors. Despite appearance, not all water storage drums are equally suitable for A. aegypti development. Exposing water storage drums to direct sunlight or increased heat may be used in conjunction with sealing containers to reduce production of A. aegypti when draining and chemical treatment are impractical.

  18. Breeding of Aedes aegypti (L.) and Aedes albopictus (Skuse) in urban housing of Sibu town, Sarawak.

    PubMed

    Seng, C M; Jute, N

    1994-09-01

    An Aedes survey using various larval survey methods was conducted in 12 urban housing areas and 29 vacant lands in Sibu town proper. Aedes albopictus larvae were found in all areas surveyed while Aedes aegypti larvae were present in 10 localities and 4 vacant lands. There were no significant difference in the house index, breteau and larval density index of these two Aedes (Stegomyia) species from the survey areas. The proportion of containers positive with Ae. aegypti and Ae. albopictus in area outside the house compound and near the house fencing were 3.2 times higher than outdoor compound. The indoor/outdoor breeding ratio for Ae. aegypti alone is 1.6:1. The most preferred breeding habitats outdoor were plastic cups and used tires while indoor habitats were ant traps and flower vases. In the vacant lands, the average number of larvae per containers was significantly higher than in houses and over 51% of the containers inspected were positive. Shared breeding between Ae. aegypti and Ae. albopictus larvae accounted for 9% in house surveys and 4.5% in vacant land survey. The use of various methods in Aedes larval survey may provide essential information in the study of vector epidemiology in dengue and dengue hemorrhagic fever transmission.

  19. DNA Sequencing Reveals the Midgut Microbiota of Diamondback Moth, Plutella xylostella (L.) and a Possible Relationship with Insecticide Resistance

    PubMed Central

    Xia, Xiaofeng; Zheng, Dandan; Zhong, Huanzi; Qin, Bingcai; Gurr, Geoff M.; Vasseur, Liette; Lin, Hailan; Bai, Jianlin; He, Weiyi; You, Minsheng

    2013-01-01

    Background Insect midgut microbiota is important in host nutrition, development and immune response. Recent studies indicate possible links between insect gut microbiota and resistance to biological and chemical toxins. Studies of this phenomenon and symbionts in general have been hampered by difficulties in culture-based approach. In the present study, DNA sequencing was used to examine the midgut microbiota of diamondback moth (DBM), Plutella xylostella (L.), a destructive pest that attacks cruciferous crops worldwide. Its ability to develop resistance to many types of synthetic insecticide and even Bacillus thuringiensis toxins makes it an important species to study. Methodology/Principal Findings Bacteria of the DBM larval midgut in a susceptible and two insecticide (chlorpyrifos and fipronil) resistant lines were examined by Illumina sequencing sampled from an insect generation that was not exposed to insecticide. This revealed that more than 97% of the bacteria were from three orders: Enterobacteriales, Vibrionales and Lactobacillales. Both insecticide-resistant lines had more Lactobacillales and the much scarcer taxa Pseudomonadales and Xanthomonadales with fewer Enterobacteriales compared with the susceptible strain. Consistent with this, a second study observed an increase in the proportion of Lactobacillales in the midgut of DBM individuals from a generation treated with insecticides. Conclusions/Significance This is the first report of high-throughput DNA sequencing of the entire microbiota of DBM. It reveals differences related to inter- and intra-generational exposure to insecticides. Differences in the midgut microbiota among susceptible and insecticide-resistant lines are independent of insecticide exposure in the sampled generations. While this is consistent with the hypothesis that Lactobacillales or other scarcer taxa play a role in conferring DBM insecticide resistance, further studies are necessary to rule out other possibilities. Findings

  20. Discovery of midgut genes for the RNA interference control of corn rootworm.

    PubMed

    Hu, Xu; Richtman, Nina M; Zhao, Jian-Zhou; Duncan, Keith E; Niu, Xiping; Procyk, Lisa A; Oneal, Meghan A; Kernodle, Bliss M; Steimel, Joseph P; Crane, Virginia C; Sandahl, Gary; Ritland, Julie L; Howard, Richard J; Presnail, James K; Lu, Albert L; Wu, Gusui

    2016-01-01

    RNA interference (RNAi) is a promising new technology for corn rootworm control. This paper presents the discovery of new gene targets - dvssj1 and dvssj2, in western corn rootworm (WCR). Dvssj1 and dvssj2 are orthologs of the Drosophila genes snakeskin (ssk) and mesh, respectively. These genes encode membrane proteins associated with smooth septate junctions (SSJ) which are required for intestinal barrier function. Based on bioinformatics analysis, dvssj1 appears to be an arthropod-specific gene. Diet based insect feeding assays using double-stranded RNA (dsRNA) targeting dvssj1 and dvssj2 demonstrate targeted mRNA suppression, larval growth inhibition, and mortality. In RNAi treated WCR, injury to the midgut was manifested by "blebbing" of the midgut epithelium into the gut lumen. Ultrastructural examination of midgut epithelial cells revealed apoptosis and regenerative activities. Transgenic plants expressing dsRNA targeting dvssj1 show insecticidal activity and significant plant protection from WCR damage. The data indicate that dvssj1 and dvssj2 are effective gene targets for the control of WCR using RNAi technology, by apparent suppression of production of their respective smooth septate junction membrane proteins located within the intestinal lining, leading to growth inhibition and mortality. PMID:27464714

  1. Midgut lysozymes of Lucilia sericata - new antimicrobials involved in maggot debridement therapy.

    PubMed

    Valachova, I; Takac, P; Majtan, J

    2014-12-01

    Larvae of Lucilia sericata are used for maggot debridement therapy (MDT) because of their ability to remove necrotic tissue and eradicate bacterial pathogens of infected wounds. So far, very few antibacterial factors have been fully characterized (eg lucifensin). Using a molecular approach, some other putative antimicrobial compounds, including three novel lysozymes, have been previously identified and predicted to be involved in MDT. Nevertheless, data on lysozymes tissue origin and their functions have never been elucidated. Therefore, the aim of this study was to investigate the expression of three lysozymes in L. sericata and confirm their antibacterial effects within MDT. Moreover, we characterized the eradication process of bacteria within the digestive system of maggots and determined the role of lysozymes in this process. We found that three lysozymes are expressed in specific sections of the L. sericata midgut. Recombinant lysozymes displayed comparable antibacterial activity against Micrococcus luteus. Furthermore, the majority of Gram-positive bacteria were destroyed in vivo within the particular section of the L. sericata midgut where lysozymes are produced. Larval ingestion and subsequent eradication of wound pathogens during their passage through the intestine of maggots are due to, at least in part, antibacterial action of three midgut lysozymes.

  2. Discovery of midgut genes for the RNA interference control of corn rootworm

    PubMed Central

    Hu, Xu; Richtman, Nina M.; Zhao, Jian-Zhou; Duncan, Keith E.; Niu, Xiping; Procyk, Lisa A.; Oneal, Meghan A.; Kernodle, Bliss M.; Steimel, Joseph P.; Crane, Virginia C.; Sandahl, Gary; Ritland, Julie L.; Howard, Richard J.; Presnail, James K.; Lu, Albert L.; Wu, Gusui

    2016-01-01

    RNA interference (RNAi) is a promising new technology for corn rootworm control. This paper presents the discovery of new gene targets - dvssj1 and dvssj2, in western corn rootworm (WCR). Dvssj1 and dvssj2 are orthologs of the Drosophila genes snakeskin (ssk) and mesh, respectively. These genes encode membrane proteins associated with smooth septate junctions (SSJ) which are required for intestinal barrier function. Based on bioinformatics analysis, dvssj1 appears to be an arthropod-specific gene. Diet based insect feeding assays using double-stranded RNA (dsRNA) targeting dvssj1 and dvssj2 demonstrate targeted mRNA suppression, larval growth inhibition, and mortality. In RNAi treated WCR, injury to the midgut was manifested by “blebbing” of the midgut epithelium into the gut lumen. Ultrastructural examination of midgut epithelial cells revealed apoptosis and regenerative activities. Transgenic plants expressing dsRNA targeting dvssj1 show insecticidal activity and significant plant protection from WCR damage. The data indicate that dvssj1 and dvssj2 are effective gene targets for the control of WCR using RNAi technology, by apparent suppression of production of their respective smooth septate junction membrane proteins located within the intestinal lining, leading to growth inhibition and mortality. PMID:27464714

  3. Cyanobacteria associated with Anopheles albimanus (Diptera: Culicidae) larval habitats in southern Mexico.

    PubMed

    Vázquez-Martínez, M Guadalupe; Rodríguez, Mario H; Arredondo-Jiménez, Juan I; Méndez-Sanchez, José D; Bond-Compeán, J Guillermo; Cold-Morgan, Michelle

    2002-11-01

    Cyanobacteria associated with Anopheles albimanus Wiedemann larval habitats from southern Chiapas, Mexico, were isolated and identified from water samples and larval midguts using selective medium BG-11. Larval breeding sites were classified according to their hydrology and dominant vegetation. Cyanobacteria isolated in water samples were recorded and analyzed according to hydrological and vegetation habitat breeding types, and mosquito larval abundance. In total, 19 cyanobacteria species were isolated from water samples. Overall, the most frequently isolated cyanobacterial taxa were Phormidium sp., Oscillatoria sp., Aphanocapsa cf. littoralis, Lyngbya lutea, P. animalis, and Anabaena cf. spiroides. Cyanobacteria were especially abundant in estuaries, irrigation canals, river margins and mangrove lagoons, and more cyanobacteria were isolated from Brachiaria mutica, Ceratophyllum demersum, and Hymenachne amplexicaulis habitats. Cyanobacteria were found in habitats with low to high An. albimanus larval abundance, but Aphanocapsa cf. littoralis was associated with habitats of low larval abundance. No correlation was found between water chemistry parameters and the presence of cyanobacteria, however, water temperature (29.2-29.4 degrees C) and phosphate concentration (79.8-136.5 ppb) were associated with medium and high mosquito larvae abundance. In An. albimanus larval midguts, only six species of cyanobacteria were isolated, the majority being from the most abundant cyanobacteria in water samples.

  4. A lepidopteran-specific gene family encoding valine-rich midgut proteins.

    PubMed

    Odman-Naresh, Jothini; Duevel, Margret; Muthukrishnan, Subbaratnam; Merzendorfer, Hans

    2013-01-01

    Many lepidopteran larvae are serious agricultural pests due to their feeding activity. Digestion of the plant diet occurs mainly in the midgut and is facilitated by the peritrophic matrix (PM), an extracellular sac-like structure, which lines the midgut epithelium and creates different digestive compartments. The PM is attracting increasing attention to control lepidopteran pests by interfering with this vital function. To identify novel PM components and thus potential targets for insecticides, we performed an immunoscreening with anti-PM antibodies using an expression library representing the larval midgut transcriptome of the tobacco hornworm, Manduca sexta. We identified three cDNAs encoding valine-rich midgut proteins of M. sexta (MsVmps), which appear to be loosely associated with the PM. They are members of a lepidopteran-specific family of nine VMP genes, which are exclusively expressed in larval stages in M. sexta. Most of the MsVMP transcripts are detected in the posterior midgut, with the highest levels observed for MsVMP1. To obtain further insight into Vmp function, we expressed MsVMP1 in insect cells and purified the recombinant protein. Lectin staining and glycosidase treatment indicated that MsVmp1 is highly O-glycosylated. In line with results from qPCR, immunoblots revealed that MsVmp1 amounts are highest in feeding larvae, while MsVmp1 is undetectable in starving and molting larvae. Finally using immunocytochemistry, we demonstrated that MsVmp1 localizes to the cytosol of columnar cells, which secrete MsVmp1 into the ectoperitrophic space in feeding larvae. In starving and molting larvae, MsVmp1 is found in the gut lumen, suggesting that the PM has increased its permeability. The present study demonstrates that lepidopteran species including many agricultural pests have evolved a set of unique proteins that are not found in any other taxon and thus may reflect an important adaptation in the highly specialized lepidopteran digestive tract facing

  5. Aedes aegypti genomics.

    PubMed

    Severson, David W; Knudson, Dennis L; Soares, Marcelo B; Loftus, Brendan J

    2004-07-01

    The mosquito, Aedes aegypti, is the primary, worldwide arthropod vector for the yellow fever and dengue viruses. As it is also one of the most tractable mosquito species for laboratory studies, it has been and remains one of the most intensively studied arthropod species. This has resulted in the development of detailed genetic and physical maps for Ae. aegypti and considerable insight into its genome organization. The research community is well-advanced in developing important molecular tools that will facilitate a whole genome sequencing effort. This includes generation of BAC clone end sequences, physical mapping of selected BAC clones and generation of EST sequences. Whole genome sequence information for Ae. aegypti will provide important insight into mosquito chromosome evolution and allow for the identification of genes and gene function. These functions may be common to all mosquitoes or perhaps unique to individual species, possibly specific to host-seeking and blood-feeding behaviors, as well as the innate immune response to pathogens encountered during blood-feeding. This information will be invaluable to the global effort to develop novel strategies for preventing arthropod-borne disease transmission.

  6. Recurrent Midgut Bleeding due to Jejunal Angioleiomyoma

    PubMed Central

    Mityushin, Petr

    2016-01-01

    Angioleiomyoma being a type of true smooth muscle gastrointestinal tumors can lead to serious life-threatening gastrointestinal bleeding. We report a case of 21-year-old male patient with recurrent midgut bleeding. Contrast-enhanced CT revealed highly vascular small bowel neoplasm. The patient underwent laparotomy with bowel resection and recovered uneventfully. Histopathology revealed jejunal angioleiomyoma. PMID:27668116

  7. Recurrent Midgut Bleeding due to Jejunal Angioleiomyoma.

    PubMed

    Gachabayov, Mahir; Mityushin, Petr

    2016-01-01

    Angioleiomyoma being a type of true smooth muscle gastrointestinal tumors can lead to serious life-threatening gastrointestinal bleeding. We report a case of 21-year-old male patient with recurrent midgut bleeding. Contrast-enhanced CT revealed highly vascular small bowel neoplasm. The patient underwent laparotomy with bowel resection and recovered uneventfully. Histopathology revealed jejunal angioleiomyoma. PMID:27668116

  8. Recurrent Midgut Bleeding due to Jejunal Angioleiomyoma

    PubMed Central

    Mityushin, Petr

    2016-01-01

    Angioleiomyoma being a type of true smooth muscle gastrointestinal tumors can lead to serious life-threatening gastrointestinal bleeding. We report a case of 21-year-old male patient with recurrent midgut bleeding. Contrast-enhanced CT revealed highly vascular small bowel neoplasm. The patient underwent laparotomy with bowel resection and recovered uneventfully. Histopathology revealed jejunal angioleiomyoma.

  9. The receptor of Bacillus sphaericus binary toxin in Culex pipiens (Diptera: Culicidae) midgut: molecular cloning and expression.

    PubMed

    Darboux, I; Nielsen-LeRoux, C; Charles, J F; Pauron, D

    2001-09-01

    Culex pipiens larval midgut is the primary target of the binary toxin (Bin) present in parasporal inclusions of Bacillus sphaericus. Cpm1, a 60-kDa protein purified from brush border membranes, has been proposed as the receptor of the Bin toxin in the midgut epithelial cells of mosquitoes. We have cloned and characterized the corresponding cDNA from midgut of Culex pipiens larvae. The open reading frame predicted a 580 amino-acid protein with a putative signal peptide at the N-terminus and a putative GPI-anchoring signal at the C-terminus. The amino acid sequence of the cloned Cpm1 exhibited 39-43% identities with insect maltases (alpha-glucosidases and alpha-amylases). Recombinant Cpm1 expressed in E. coli specifically bound to the Bin toxin and had a significant alpha-glucosidase activity but no alpha-amylase activity. These results support the view that Cpm1 is an alpha-glucosidase expressed in Culex midgut where it constitutes the receptor for the Bin toxin. To date, this is the first component involved in the mosquitocidal activity of the Bacillus sphaericus Bin toxin to be characterized. Its identification provides a key step to elucidate the mode of action of the Bin toxin and the mechanisms of resistance developed against it by some mosquito strains. PMID:11483434

  10. Roles and regulation of autophagy and apoptosis in the remodelling of the lepidopteran midgut epithelium during metamorphosis.

    PubMed

    Romanelli, Davide; Casartelli, Morena; Cappellozza, Silvia; de Eguileor, Magda; Tettamanti, Gianluca

    2016-01-01

    We previously showed that autophagy and apoptosis occur in the removal of the lepidopteran larval midgut during metamorphosis. However, their roles in this context and the molecular pathways underlying their activation and regulation were only hypothesized. The results of the present study better clarify the timing of the activation of these two processes: autophagic and apoptotic genes are transcribed at the beginning of metamorphosis, but apoptosis intervenes after autophagy. To investigate the mechanisms that promote the activation of autophagy and apoptosis, we designed a set of experiments based on injections of 20-hydroxyecdysone (20E). Our data demonstrate that autophagy is induced at the end of the last larval stage by the 20E commitment peak, while the onset of apoptosis occurs concomitantly with the 20E metamorphic peak. By impairing autophagic flux, the midgut epithelium degenerated faster, and higher caspase activity was observed compared to controls, whereas inhibiting caspase activation caused a severe delay in epithelial degeneration. Our data demonstrate that autophagy plays a pro-survival function in the silkworm midgut during metamorphosis, while apoptosis is the major process that drives the demise of the epithelium. The evidence collected in this study seems to exclude the occurrence of autophagic cell death in this setting. PMID:27609527

  11. Roles and regulation of autophagy and apoptosis in the remodelling of the lepidopteran midgut epithelium during metamorphosis

    NASA Astrophysics Data System (ADS)

    Romanelli, Davide; Casartelli, Morena; Cappellozza, Silvia; de Eguileor, Magda; Tettamanti, Gianluca

    2016-09-01

    We previously showed that autophagy and apoptosis occur in the removal of the lepidopteran larval midgut during metamorphosis. However, their roles in this context and the molecular pathways underlying their activation and regulation were only hypothesized. The results of the present study better clarify the timing of the activation of these two processes: autophagic and apoptotic genes are transcribed at the beginning of metamorphosis, but apoptosis intervenes after autophagy. To investigate the mechanisms that promote the activation of autophagy and apoptosis, we designed a set of experiments based on injections of 20-hydroxyecdysone (20E). Our data demonstrate that autophagy is induced at the end of the last larval stage by the 20E commitment peak, while the onset of apoptosis occurs concomitantly with the 20E metamorphic peak. By impairing autophagic flux, the midgut epithelium degenerated faster, and higher caspase activity was observed compared to controls, whereas inhibiting caspase activation caused a severe delay in epithelial degeneration. Our data demonstrate that autophagy plays a pro-survival function in the silkworm midgut during metamorphosis, while apoptosis is the major process that drives the demise of the epithelium. The evidence collected in this study seems to exclude the occurrence of autophagic cell death in this setting.

  12. Roles and regulation of autophagy and apoptosis in the remodelling of the lepidopteran midgut epithelium during metamorphosis

    PubMed Central

    Romanelli, Davide; Casartelli, Morena; Cappellozza, Silvia; de Eguileor, Magda; Tettamanti, Gianluca

    2016-01-01

    We previously showed that autophagy and apoptosis occur in the removal of the lepidopteran larval midgut during metamorphosis. However, their roles in this context and the molecular pathways underlying their activation and regulation were only hypothesized. The results of the present study better clarify the timing of the activation of these two processes: autophagic and apoptotic genes are transcribed at the beginning of metamorphosis, but apoptosis intervenes after autophagy. To investigate the mechanisms that promote the activation of autophagy and apoptosis, we designed a set of experiments based on injections of 20-hydroxyecdysone (20E). Our data demonstrate that autophagy is induced at the end of the last larval stage by the 20E commitment peak, while the onset of apoptosis occurs concomitantly with the 20E metamorphic peak. By impairing autophagic flux, the midgut epithelium degenerated faster, and higher caspase activity was observed compared to controls, whereas inhibiting caspase activation caused a severe delay in epithelial degeneration. Our data demonstrate that autophagy plays a pro-survival function in the silkworm midgut during metamorphosis, while apoptosis is the major process that drives the demise of the epithelium. The evidence collected in this study seems to exclude the occurrence of autophagic cell death in this setting. PMID:27609527

  13. Larvicide and oviposition deterrent effects of fruit and leaf extracts from Melia azedarach L. on Aedes aegypti (L.) (Diptera: Culicidae).

    PubMed

    Coria, C; Almiron, W; Valladares, G; Carpinella, C; Ludueña, F; Defago, M; Palacios, S

    2008-05-01

    Aedes aegypti (L.) (Diptera: Culicidae), the main urban vector of dengue, has developed resistance to various insecticides, making its control increasingly difficult. We explored the effects of Argentine Melia azedarach L. (Meliaceae) fruit and senescent leaf extracts on Ae. aegypti larval development and survival, by rearing cohorts of first instar mosquitoes in water with different extract concentrations. We also analysed oviposition deterrent activity in choice tests with extract-treated ovitraps. The leaf extract showed a strong larvicide activity, with all larvae dying before pupation, and significantly delayed development time. It strongly inhibited oviposition by Ae. aegypti females. The fruit extract showed much weaker effects. This first report of highly effective larvicidal, growth regulating and oviposition deterrent activity of a senescent leaf extract of M. azedarach against Ae. aegypti, suggests that such extract could represent a promising tool in the management of this mosquito pest.

  14. Breeding habitats of Aedes aegypti (L) and Aedes. albopictus (Skuse) in villages of Barru, South Sulawesi, Indonesia.

    PubMed

    Ishak, H; Miyagi, I; Toma, T; Kamimura, K

    1997-12-01

    The breeding habitats of the dengue vector, Aedes aegypti and Aedes albopictus, were studied using larval collection method inside and outside houses in 6 villages of Barru, South Sulawesi, Indonesia from July 1994 to August 1995. Aedes aegypti was the dominant species, being abundant indoors especially in the coastal areas. Aedes albopictus was breeding primarily in outdoor containers in the hill and mountain areas. Earthen jar was the most common breeding habitat of Aedes aegypti in all villages surveyed. Drum can was the most common outdoor breeding habitat of Aedes albopictus in the hill and mountain areas. The high Breteau indices of Aedes aegypti and Aedes albopictus suggests that these species may play an important role in the transmission of dengue hemorrhagic fever in Barru where epidemics of the fever occur occasionally.

  15. Biological differences between brackish and fresh water-derived Aedes aegypti from two locations in the Jaffna peninsula of Sri Lanka and the implications for arboviral disease transmission.

    PubMed

    Ramasamy, Ranjan; Jude, Pavilupillai J; Veluppillai, Thabothiny; Eswaramohan, Thampoe; Surendran, Sinnathamby N

    2014-01-01

    The mainly fresh water arboviral vector Aedes aegypti L. (Diptera: Culicidae) can also undergo pre-imaginal development in brackish water of up to 15 ppt (parts per thousand) salt in coastal areas. We investigated differences in salinity tolerance, egg laying preference, egg hatching and larval development times and resistance to common insecticides in Ae. aegypti collected from brackish and fresh water habitats in Jaffna, Sri Lanka. Brackish water-derived Ae. aegypti were more tolerant of salinity than fresh water-derived Ae. aegypti and this difference was only partly reduced after their transfer to fresh water for up to five generations. Brackish water-derived Ae. aegypti did not significantly discriminate between 10 ppt salt brackish water and fresh water for oviposition, while fresh water-derived Ae. aegypti preferred fresh water. The hatching of eggs from both brackish and fresh water-derived Ae. aegypti was less efficient and the time taken for larvae to develop into pupae was prolonged in 10 ppt salt brackish water. Ae. aegypti isolated from coastal brackish water were less resistant to the organophosphate insecticide malathion than inland fresh water Ae. aegypti. Brackish and fresh water-derived Ae. aegypti however were able to mate and produce viable offspring in the laboratory. The results suggest that development in brackish water is characterised by pertinent biological changes, and that there is restricted genetic exchange between coastal brackish and inland fresh water Ae. aegypti isolates from sites 5 km apart. The findings highlight the need for monitoring Ae. aegypti developing in coastal brackish waters and extending vector control measures to their habitats.

  16. Biological differences between brackish and fresh water-derived Aedes aegypti from two locations in the Jaffna peninsula of Sri Lanka and the implications for arboviral disease transmission.

    PubMed

    Ramasamy, Ranjan; Jude, Pavilupillai J; Veluppillai, Thabothiny; Eswaramohan, Thampoe; Surendran, Sinnathamby N

    2014-01-01

    The mainly fresh water arboviral vector Aedes aegypti L. (Diptera: Culicidae) can also undergo pre-imaginal development in brackish water of up to 15 ppt (parts per thousand) salt in coastal areas. We investigated differences in salinity tolerance, egg laying preference, egg hatching and larval development times and resistance to common insecticides in Ae. aegypti collected from brackish and fresh water habitats in Jaffna, Sri Lanka. Brackish water-derived Ae. aegypti were more tolerant of salinity than fresh water-derived Ae. aegypti and this difference was only partly reduced after their transfer to fresh water for up to five generations. Brackish water-derived Ae. aegypti did not significantly discriminate between 10 ppt salt brackish water and fresh water for oviposition, while fresh water-derived Ae. aegypti preferred fresh water. The hatching of eggs from both brackish and fresh water-derived Ae. aegypti was less efficient and the time taken for larvae to develop into pupae was prolonged in 10 ppt salt brackish water. Ae. aegypti isolated from coastal brackish water were less resistant to the organophosphate insecticide malathion than inland fresh water Ae. aegypti. Brackish and fresh water-derived Ae. aegypti however were able to mate and produce viable offspring in the laboratory. The results suggest that development in brackish water is characterised by pertinent biological changes, and that there is restricted genetic exchange between coastal brackish and inland fresh water Ae. aegypti isolates from sites 5 km apart. The findings highlight the need for monitoring Ae. aegypti developing in coastal brackish waters and extending vector control measures to their habitats. PMID:25170879

  17. Comparison of Vector Competence of Aedes mediovittatus and Aedes aegypti for Dengue Virus: Implications for Dengue Control in the Caribbean

    PubMed Central

    Poole-Smith, B. Katherine; Hemme, Ryan R.; Delorey, Mark; Felix, Gilberto; Gonzalez, Andrea L.; Amador, Manuel; Hunsperger, Elizabeth A.; Barrera, Roberto

    2015-01-01

    Background Aedes mediovittatus mosquitoes are found throughout the Greater Antilles in the Caribbean and often share the same larval habitats with Ae. Aegypti, the primary vector for dengue virus (DENV). Implementation of vector control measures to control dengue that specifically target Ae. Aegypti may not control DENV transmission in Puerto Rico (PR). Even if Ae. Aegypti is eliminated or DENV refractory mosquitoes are released, DENV transmission may not cease when other competent mosquito species like Ae. Mediovittatus are present. To compare vector competence of Ae. Mediovittatus and Ae. Aegypti mosquitoes, we studied relative infection and transmission rates for all four DENV serotypes. Methods To compare the vector competence of Ae. Mediovittatus and Ae. Aegypti, mosquitoes were exposed to DENV 1–4 per os at viral titers of 5–6 logs plaque-forming unit (pfu) equivalents. At 14 days post infectious bloodmeal, viral RNA was extracted and tested by qRT-PCR to determine infection and transmission rates. Infection and transmission rates were analyzed with a generalized linear model assuming a binomial distribution. Results Ae. Aegypti had significantly higher DENV-4 infection and transmission rates than Ae. mediovittatus. Conclusions This study determined that Ae. Mediovittatus is a competent DENV vector. Therefore dengue prevention programs in PR and the Caribbean should consider both Ae. Mediovittatus and Ae. Aegypti mosquitoes in their vector control programs. PMID:25658951

  18. [Aedes aegypti in French Guiana. Some aspects of history, general ecology and vertical transmission of the dengue virus].

    PubMed

    Fouque, F; Carinci, R

    1996-01-01

    Aedes aegypti is suspected to be present in the country since the late 18th century, and was responsible of urban yellow fever epidemics in the last century. This mosquito was identified for the first time in French Guiana in 1902. More recently, in 1940, an eradication campaign started and Aedes aegypti was eradicated between 1950 and 1963, date of the reinfestation. During the past 30 years, some dengue outbreaks occurred every 2 to 6 years, and the first dengue haemorrhagic fever epidemic spread over the country in 1992. Actually, Ae. aegypti is distributed almost all inhabited areas of French Guiana: in the towns, villages, smaller human settlements, and was also found in a wild area. The most frequent Ae. aegypti breeding-sources are the outside discarded small containers, other less frequent breeding-sites are the outside flower pots and the outside big containers. The type of breeding-source significantly influences the duration of larval and pupal development. In French Guiana, Ae. aegypti is the only vector of dengue. The vertical transmission of dengue viruses under field conditions was demonstrated. Dengue is thus endemic in the country and has almost the same distribution as Ae. aegypti, with most probably the same possibilities of extension. Ae. aegypti can be considered not only as vector and an amplificator of dengue in French Guiana, but also as a reservoir, even if occasional.

  19. Transstadial Effects of Bti on Traits of Aedes aegypti and Infection with Dengue Virus

    PubMed Central

    Alto, Barry W.; Lord, Cynthia C.

    2016-01-01

    Most mosquito control efforts are primarily focused on reducing the adult population size mediated by reductions in the larval population, which should lower risk of disease transmission. Although the aim of larviciding is to reduce larval abundance and thus recruitment of adults, nonlethal effects on adults are possible, including transstadial effects on phenotypes of adults such as survival and pathogen infection and transmission. In addition, the mortality induced by control efforts may act in conjunction with other sources of mosquito mortality in nature. The consequences of these effects and interactions may alter the potential of the population to transmit pathogens. We tested experimentally the combined effects of a larvicide (Bacillus thuringiensis ssp. israelensis, Bti) and competition during the larval stages on subsequent Aedes aegypti (Linnaeus) traits, population performance, and susceptibility to dengue-1 virus infection. Ae. aegypti that survived exposure to Bti experienced accelerated development, were larger, and produced more eggs with increasing amounts of Bti, consistent with competitive release among surviving mosquitoes. Changing larval density had no significant interactive effect with Bti treatment on development and growth to adulthood. Larval density, but not Bti or treatment interaction, had a strong effect on survival of adult Ae. aegypti females. There were sharper declines in cumulative daily survival of adults from crowded than uncrowded larval conditions, suggesting that high competition conditions of larvae may be an impediment to transmission of dengue viruses. Rates of infection and dengue-1 virus disseminated infections were found to be 87±13% and 88±12%, respectively. There were no significant treatment effects on infection measurements. Our findings suggest that larvicide campaigns using Bti may reduce the number of emerged adults, but survivors will have a fitness advantage (growth, development, enhanced production of eggs

  20. Association of Cry1Ac Toxin Resistance in Helicoverpa zea (Boddie) with Increased Alkaline Phosphatase Levels in the Midgut Lumen

    PubMed Central

    Caccia, Silvia; Moar, William J.; Chandrashekhar, Jayadevi; Oppert, Cris; Anilkumar, Konasale J.; Jurat-Fuentes, Juan Luis

    2012-01-01

    Resistance to Bacillus thuringiensis Cry1Ac toxin was characterized in a population of Helicoverpa zea larvae previously shown not to have an alteration in toxin binding as the primary resistance mechanism to this toxin. Cry1Ac-selected larvae (AR1) were resistant to protoxins and toxins of Cry1Ab, Cry1Ac, and the corresponding modified proteins lacking helix α-1 (Cry1AbMod and Cry1AcMod). When comparing brush border membrane vesicles (BBMVs) prepared from susceptible (LC) and AR1 larval midguts, there were only negligible differences in overall Cry1Ac toxin binding, though AR1 had 18% reversible binding, in contrast to LC, in which all binding was irreversible. However, no differences were detected in Cry1Ac-induced pore formation activity in BBMVs from both strains. Enzymatic activities of two putative Cry1Ac receptors (aminopeptidase N [APN] and alkaline phosphatase [ALP]) were significantly reduced (2-fold and 3-fold, respectively) in BBMVs from AR1 compared to LC larvae. These reductions corresponded to reduced protein levels in midgut luminal contents only in the case of ALP, with an almost 10-fold increase in specific ALP activity in midgut fluids from AR1 compared to LC larvae. Partially purified H. zea ALP bound Cry1Ac toxin in ligand blots and competed with Cry1Ac toxin for BBMV binding. Based on these results, we suggest the existence of at least one mechanism of resistance to Cry1A toxins in H. zea involving binding of Cry1Ac toxin to an ALP receptor in the larval midgut lumen of resistant larvae. PMID:22685140

  1. Association of Cry1Ac toxin resistance in Helicoverpa zea (Boddie) with increased alkaline phosphatase levels in the midgut lumen.

    PubMed

    Caccia, Silvia; Moar, William J; Chandrashekhar, Jayadevi; Oppert, Cris; Anilkumar, Konasale J; Jurat-Fuentes, Juan Luis; Ferré, Juan

    2012-08-01

    Resistance to Bacillus thuringiensis Cry1Ac toxin was characterized in a population of Helicoverpa zea larvae previously shown not to have an alteration in toxin binding as the primary resistance mechanism to this toxin. Cry1Ac-selected larvae (AR1) were resistant to protoxins and toxins of Cry1Ab, Cry1Ac, and the corresponding modified proteins lacking helix α-1 (Cry1AbMod and Cry1AcMod). When comparing brush border membrane vesicles (BBMVs) prepared from susceptible (LC) and AR1 larval midguts, there were only negligible differences in overall Cry1Ac toxin binding, though AR1 had 18% reversible binding, in contrast to LC, in which all binding was irreversible. However, no differences were detected in Cry1Ac-induced pore formation activity in BBMVs from both strains. Enzymatic activities of two putative Cry1Ac receptors (aminopeptidase N [APN] and alkaline phosphatase [ALP]) were significantly reduced (2-fold and 3-fold, respectively) in BBMVs from AR1 compared to LC larvae. These reductions corresponded to reduced protein levels in midgut luminal contents only in the case of ALP, with an almost 10-fold increase in specific ALP activity in midgut fluids from AR1 compared to LC larvae. Partially purified H. zea ALP bound Cry1Ac toxin in ligand blots and competed with Cry1Ac toxin for BBMV binding. Based on these results, we suggest the existence of at least one mechanism of resistance to Cry1A toxins in H. zea involving binding of Cry1Ac toxin to an ALP receptor in the larval midgut lumen of resistant larvae. PMID:22685140

  2. Baseline data on Aedes aegypti populations in Santo Domingo, Dominican Republic.

    PubMed

    Tidwell, M A; Williams, D C; Carvalho Tidwell, T; Peña, C J; Gwinn, T A; Focks, D A; Zaglul, A; Mercedes, M

    1990-09-01

    Baseline field studies were conducted from April 1987 to July 1988 on Aedes aegypti in Santo Domingo, an endemic area for dengue fever. Premise, container and Breteau indices were measured in one treated area and 2 nearby control areas. These indices averaged 69.6, 46.3 and 142.1, respectively. The principal larval habitats of Ae. aegypti were 208-liter (55-gal) concrete-lined drums. The estimated daily adult production was approximately 60 per house. Adult mosquito populations were monitored using oviposition traps and by sweep net collections. There was no correlation between adult abundance and the larval indices. Monitoring the natural adult densities was more efficient for evaluating the impact of ULV malathion application than the use of standard bioassay procedures.

  3. Larvicidal activity of some Euphorbiaceae plant extracts against Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Rahuman, A Abdul; Gopalakrishnan, Geetha; Venkatesan, P; Geetha, Kannappan

    2008-04-01

    Larvicidal activity of ethyl acetate, butanol, and petroleum ether extracts of five species of Euphorbiaceae plants, Jatropha curcas, Pedilanthus tithymaloides, Phyllanthus amarus, Euphorbia hirta, and Euphorbia tirucalli, were tested against the early fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus (Say). The larval mortality was observed after 24 h of exposure. All extracts showed low larvicidal effects; however, the highest larval mortality was found in petroleum ether extract. The LC50 value of petroleum ether extracts of J. curcas, P. tithymaloides, P. amarus, E. hirta, and E. tirucalli were 8.79, 55.26, 90.92, 272.36, and 4.25 ppm, respectively, against A. aegypti and 11.34, 76.61, 113.40, 424.94, and 5.52 ppm, respectively, against C quinquefasciatus. Of the various ratios tested, the petroleum ether extracts of J. curcas and E. tirucalli were observed to be more efficient than the other plant extracts. It is, therefore, suggested that E. tirucalli can be applied as an ideal potential larvicide against A. aegypti and C. quinquefasciatus. This is an ideal ecofriendly approach for the control of the dengue vector, A. aegypti, and the lymphatic filariasis vector, C. quinquefasciatus.

  4. Genetic differentiation of the dengue vector, Aedes aegypti (Ho Chi Minh City, Vietnam) using microsatellite markers.

    PubMed

    Huber, K; Le Loan, L; Hoang, T H; Ravel, S; Rodhain, F; Failloux, A-B

    2002-09-01

    Dengue haemorrhagic fever emerged in the 1950s and has become a major public health concern in most Asian countries. In Vietnam, little is known about the intraspecific variation of the vector and its consequences on vectorial capacity. Here we report the use of microsatellite markers to differentiate Aedes aegypti populations in Ho Chi Minh City, a typical, overcrowded Asian city. Six microsatellite loci, with 5-14 alleles per locus, were scored in 20 mosquito samples collected in 1998 in Ho Chi Minh City. We found substantial differentiation among Ae. aegypti populations from the outskirts, whereas populations from the centre of the city showed less differentiation. These results are consistent with the hypothesis that populations of Ae. aegypti in central Ho Chi Minh City are panmictic because there are abundant larval breeding sites and an abundance of humans for adults to feed upon. In contrast, populations on the outskirts become differentiated largely through the processes of genetic drift because larval breeding sites are not as abundant. These findings implicate human activities associated with urbanization, as factors shaping the genetic structure of Ae. aegypti populations.

  5. Flavivirus susceptibility in Aedes aegypti.

    PubMed

    Black, William C; Bennett, Kristine E; Gorrochótegui-Escalante, Norma; Barillas-Mury, Carolina V; Fernández-Salas, Ildefonso; de Lourdes Muñoz, María; Farfán-Alé, José A; Olson, Ken E; Beaty, Barry J

    2002-01-01

    Aedes aegypti is the primary vector of yellow fever (YF) and dengue fever (DF) flaviviruses worldwide. In this review we focus on past and present research on genetic components and environmental factors in Aedes aegypti that appear to control flavivirus transmission. We review genetic relationships among Ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. We describe current research into how genetic and environmental factors jointly affect distribution of vector competence in natural populations. Based on this information, we propose a population genetic model for vector competence and discuss our recent progress in testing this model. We end with a discussion of approaches being taken to identify the genes that may control flavivirus susceptibility in Ae. aegypti.

  6. Effects of environment, dietary regime and ageing on the dengue vector microbiota: evidence of a core microbiota throughout Aedes aegypti lifespan

    PubMed Central

    David, Mariana Rocha; dos Santos, Lilha Maria Barbosa; Vicente, Ana Carolina Paulo; Maciel-de-Freitas, Rafael

    2016-01-01

    Abstract Mosquito midgut microbiota is a key component of vector competence, as gut bacteria can disturb pathogen development. In this study, we addressed the microbiota composition of Aedes aegypti during its lifespan, under field conditions. We also investigated the possible effects of environment, dietary regime and ageing on the gut community composition. We employed culture independent and dependent approaches to characterise vector microbiota. There was evidence of a lifelong stable core microbiota after mosquitoes were released into an urban settlement, where they presumably fed on a range of vertebrate hosts and carbohydrate sources. This core was formed mainly of bacteria belonging to the genera Pseudomonas, Acinetobacter, Aeromonas and Stenotrophomonas and to the families Oxalobacteraceae, Enterobacteriaceae and Comamonadaceae. We showed that both dietary regime and age were associated with the abundance of some bacterial groups in the Ae. aegypti microbiota. The majority of the bacterial groups we identified have been detected in the midgut of Ae. aegypti from laboratory and wild populations, indicating a possible core microbiota associated with this mosquito species. Our findings suggest that Ae. aegypti harbours a stable bacterial community during its adult life, similar to mosquito populations from distinct geographic areas, which may be further explored for arbovirus biocontrol strategies. PMID:27580348

  7. Effects of environment, dietary regime and ageing on the dengue vector microbiota: evidence of a core microbiota throughout Aedes aegypti lifespan.

    PubMed

    David, Mariana Rocha; Santos, Lilha Maria Barbosa Dos; Vicente, Ana Carolina Paulo; Maciel-de-Freitas, Rafael

    2016-09-01

    Mosquito midgut microbiota is a key component of vector competence, as gut bacteria can disturb pathogen development. In this study, we addressed the microbiota composition of Aedes aegypti during its lifespan, under field conditions. We also investigated the possible effects of environment, dietary regime and ageing on the gut community composition. We employed culture independent and dependent approaches to characterise vector microbiota. There was evidence of a lifelong stable core microbiota after mosquitoes were released into an urban settlement, where they presumably fed on a range of vertebrate hosts and carbohydrate sources. This core was formed mainly of bacteria belonging to the genera Pseudomonas, Acinetobacter, Aeromonas and Stenotrophomonas and to the families Oxalobacteraceae, Enterobacteriaceae and Comamonadaceae. We showed that both dietary regime and age were associated with the abundance of some bacterial groups in the Ae. aegypti microbiota. The majority of the bacterial groups we identified have been detected in the midgut of Ae. aegypti from laboratory and wild populations, indicating a possible core microbiota associated with this mosquito species. Our findings suggest that Ae. aegypti harbours a stable bacterial community during its adult life, similar to mosquito populations from distinct geographic areas, which may be further explored for arbovirus biocontrol strategies. PMID:27580348

  8. Emerging role of lipid droplets in Aedes aegypti immune response against bacteria and Dengue virus

    PubMed Central

    Barletta, Ana Beatriz Ferreira; Alves, Liliane Rosa; Nascimento Silva, Maria Clara L.; Sim, Shuzhen; Dimopoulos, George; Liechocki, Sally; Maya-Monteiro, Clarissa M.; Sorgine, Marcos H. Ferreira

    2016-01-01

    In mammals, lipid droplets (LDs) are ubiquitous organelles that modulate immune and inflammatory responses through the production of lipid mediators. In insects, it is unknown whether LDs play any role during the development of immune responses. We show that Aedes aegypti Aag2 cells – an immune responsive cell lineage – accumulates LDs when challenged with Enterobacter cloacae, Sindbis, and Dengue viruses. Microarray analysis of Aag2 challenged with E.cloacae or infected with Dengue virus revealed high transcripts levels of genes associated with lipid storage and LDs biogenesis, correlating with the increased LDs numbers in those conditions. Similarly, in mosquitoes, LDs accumulate in midgut cells in response to Serratia marcescens and Sindbis virus or when the native microbiota proliferates, following a blood meal. Also, constitutive activation of Toll and IMD pathways by knocking-down their respective negative modulators (Cactus and Caspar) increases LDs numbers in the midgut. Our results show for the first time an infection-induced LDs accumulation in response to both bacterial and viral infections in Ae. Aegypti, and we propose a role for LDs in mosquito immunity. These findings open new venues for further studies in insect immune responses associated with lipid metabolism. PMID:26887863

  9. Emerging role of lipid droplets in Aedes aegypti immune response against bacteria and Dengue virus.

    PubMed

    Barletta, Ana Beatriz Ferreira; Alves, Liliane Rosa; Silva, Maria Clara L Nascimento; Sim, Shuzhen; Dimopoulos, George; Liechocki, Sally; Maya-Monteiro, Clarissa M; Sorgine, Marcos H Ferreira

    2016-01-01

    In mammals, lipid droplets (LDs) are ubiquitous organelles that modulate immune and inflammatory responses through the production of lipid mediators. In insects, it is unknown whether LDs play any role during the development of immune responses. We show that Aedes aegypti Aag2 cells - an immune responsive cell lineage - accumulates LDs when challenged with Enterobacter cloacae, Sindbis, and Dengue viruses. Microarray analysis of Aag2 challenged with E.cloacae or infected with Dengue virus revealed high transcripts levels of genes associated with lipid storage and LDs biogenesis, correlating with the increased LDs numbers in those conditions. Similarly, in mosquitoes, LDs accumulate in midgut cells in response to Serratia marcescens and Sindbis virus or when the native microbiota proliferates, following a blood meal. Also, constitutive activation of Toll and IMD pathways by knocking-down their respective negative modulators (Cactus and Caspar) increases LDs numbers in the midgut. Our results show for the first time an infection-induced LDs accumulation in response to both bacterial and viral infections in Ae. Aegypti, and we propose a role for LDs in mosquito immunity. These findings open new venues for further studies in insect immune responses associated with lipid metabolism. PMID:26887863

  10. Genetic selection of a flavivirus-refractory strain of the yellow fever mosquito Aedes aegypti.

    PubMed

    Miller, B R; Mitchell, C J

    1991-10-01

    Two inbred (isofemale) Aedes aegypti mosquito lines were derived that manifested a resistant or susceptible phenotype following ingestion of yellow fever virus; lack of virus movement from the midgut defined the resistant phenotype. Other flaviviruses, including dengue 1-4, Uganda S, and Zika, viruses behaved in a similar fashion in the two mosquito lines. Crosses between the two lines produced progeny that were of intermediate susceptibility, indicating codominance; F2 backcrosses to the parents yielded results consistent with a major controlling genetic locus and provide evidence of a second locus capable of modulating the phenotype of the major gene. The rapid selection necessary to fix the susceptible and refractory phenotypes support the hypothesis of a single major controlling locus. Viral movement across the midgut is likely to be governed by a single major gene and modifying minor genes or a group of closely linked genes. These inbred mosquito lines will be useful in discovering the molecular basis for flavivirus resistance in Ae. aegypti.

  11. Proteomic identification of dengue virus binding proteins in Aedes aegypti mosquitoes and Aedes albopictus cells.

    PubMed

    Muñoz, Maria de Lourdes; Limón-Camacho, Gustavo; Tovar, Rosalinda; Diaz-Badillo, Alvaro; Mendoza-Hernández, Guillermo; Black, William C

    2013-01-01

    The main vector of dengue in America is the mosquito Aedes aegypti, which is infected by dengue virus (DENV) through receptors of midgut epithelial cells. The envelope protein (E) of dengue virus binds to receptors present on the host cells through its domain III that has been primarily recognized to bind cell receptors. In order to identify potential receptors, proteins from mosquito midgut tissue and C6/36 cells were purified by affinity using columns with the recombinant E protein domain III (rE-DIII) or DENV particles bound covalently to Sepharose 4B to compare and evaluate their performance to bind proteins including putative receptors from female mosquitoes of Ae. aegypti. To determine their identity mass spectrometric analysis of purified proteins separated by polyacrylamide gel electrophoresis was performed. Our results indicate that both viral particles and rE-DIII bound proteins with the same apparent molecular weights of 57 and 67 kDa. In addition, viral particles bound high molecular weight proteins. Purified proteins identified were enolase, beta-adrenergic receptor kinase (beta-ARK), translation elongation factor EF-1 alpha/Tu, and cadherin. PMID:24324976

  12. Midgut morphophysiology in Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae).

    PubMed

    de Sousa, Géssica; Conte, Helio

    2013-08-01

    Sitophilus zeamais is one of the most aggressive pests of stored grains, causing a significant decrease in the nutritional quality of the grains and major losses in economic trade. The foraging capacity of this pest is assigned to its highly efficient digestive system. Investigations on the morphofunctional features of the midgut, which is the most active region of the alimentary canal, are fundamental to understand the feeding habits of this species. In this study, the midgut of adult insects was isolated, processed, and analyzed on light microscopy, scanning and transmission electron microscopy, protein and enzymatic activities determination, including analyses of the starch hydrolysis products. In S. zeamais, the midgut was differentiated into anterior midgut and posterior midgut, and consisted of digestive, regenerative and endocrine cells. The anterior midgut showed high density of regenerative crypts. Cells containing organelles associated with protein synthesis and presence of amylases and lipases indicated that majority of the digestion process occurred in the anterior midgut. The posterior midgut exhibited numerous gastric caeca and peritrophic membrane. Cells with poorly differentiated cytoplasmic into organelles, elongated microvilli, and low enzymatic activities indicated that the posterior midgut was mainly involved in absorption.

  13. A field test for competitive effects of Aedes albopictus on A. aegypti in South Florida: differences between sites of coexistence and exclusion?

    PubMed Central

    Juliano, Steven A.; Lounibos, L. Philip; O’Meara, George F.

    2007-01-01

    We tested whether interspecific competition from Aedes albopictus had measurable effects on A. aegypti at the typical numbers of larval mosquitoes found in cemetery vases in south Florida. We also tested whether the effect of interspecific competition from A. albopictus on A. aegypti differed between sites where A. aegypti either persists or went extinct following invasion by A. albopictus. Similar experiments manipulating numbers of A. albopictus in cemetery vases were conducted at three sites of A. aegypti persistence and three sites where A. aegypti was apparently extinct. The experiments were done using numbers of larvae that were determined by observed numbers of larvae for each site, and with resources (leaf detritus) that accumulated in experimental vases placed into each field site. In both the early rainy season (when number of mosquito larvae was low) and the late rainy season (when number of mosquito larvae was high), there was a significant effect of treatment on developmental progress of experimental A. aegypti. In the late rainy season, when numbers of larvae were high, there was also a significant effect of treatment on survivorship of A. aegypti. However, the competition treatment × site type (A. aegypti persists vs extinct) interaction was never significant, indicating that the competitive effect of A. albopictus on A. aegypti did not differ systematically between persistence versus extinction sites. Thus, although competition from A. albopictus is strong under field conditions at all sites, we find no evidence that variation in the impact of interspecific competition is associated with coexistence or exclusion. Interspecific competition among larvae is thus a viable explanation for exclusion or reduction of A. aegypti in south Florida, but variation in the persistence of A. aegypti following invasion does not seem to be primarily a product of variation in the conditions in the aquatic environments of cemetery vases. PMID:15024640

  14. Changing Domesticity of Aedes aegypti in Northern Peninsular Malaysia: Reproductive Consequences and Potential Epidemiological Implications

    PubMed Central

    Saifur, Rahman G. M.; Dieng, Hamady; Hassan, Ahmad Abu; Salmah, Md Rawi Che; Satho, Tomomitsu; Miake, Fumio; Hamdan, Ahmad

    2012-01-01

    Background The domestic dengue vector Aedes aegypti mosquitoes breed in indoor containers. However, in northern peninsular Malaysia, they show equal preference for breeding in both indoor and outdoor habitats. To evaluate the epidemiological implications of this peridomestic adaptation, we examined whether Ae. aegypti exhibits decreased survival, gonotrophic activity, and fecundity due to lack of host availability and the changing breeding behavior. Methodology/Principal Findings This yearlong field surveillance identified Ae. aegypti breeding in outdoor containers on an enormous scale. Through a sequence of experiments incorporating outdoors and indoors adapting as well as adapted populations, we observed that indoors provided better environment for the survival of Ae. aegypti and the observed death patterns could be explained on the basis of a difference in body size. The duration of gonotrophic period was much shorter in large-bodied females. Fecundity tended to be greater in indoor acclimated females. We also found increased tendency to multiple feeding in outdoors adapted females, which were smaller in size compared to their outdoors breeding counterparts. Conclusion/Significance The data presented here suggest that acclimatization of Ae. aegypti to the outdoor environment may not decrease its lifespan or gonotrophic activity but rather increase breeding opportunities (increased number of discarded containers outdoors), the rate of larval development, but small body sizes at emergence. Size is likely to be correlated with disease transmission. In general, small size in Aedes females will favor increased blood-feeding frequency resulting in higher population sizes and disease occurrence. PMID:22363516

  15. The cathepsin L-like proteinases from the midgut of Tenebrio molitor larvae: sequence, properties, immunocytochemical localization and function.

    PubMed

    Cristofoletti, Plínio T; Ribeiro, Alberto F; Terra, Walter R

    2005-08-01

    CDNAs coding for five procathepsin L-like proteinases (pCALs) were cloned and sequenced from a cDNA library prepared from Tenebrio molitor larval midguts: pCAL1a (with the isoforms pCAL1b and pCAL1c), pCAL2, and pCAL3. All the pCALs have the active residues Cys 25, His 169, Asn 175, and Gln 19 (papain numbering), the ERFNIN motif of papain-like enzymes and their sequences are homologous to cathepsin L enzymes. pCAL1a was expressed in bacterial systems. It is auto-catalytically activated at low pH, has kinetic properties and N-terminal sequence identical to hemocyte cathepsin L-like proteinase (CAL) and was used to raise antibodies. Semi-quantitative RT-PCR data showed that mRNAs for pCAL2 and pCAL3 were transcribed in midgut and in lesser amounts in hemolymph, whereas that for pCAL1a was transcribed in these tissues and also in fat body, Malpighian tubules, and carcass. Imunochemical detection recognized pCAL1a translation in all tissue homogenates, except anterior midgut. At this region, the presence of pCAL2 is suggested on the grounds of electrophoretical migration and high recovery of CAL2 activity from anterior midgut cells and from isolated midgut contents. Immunocytochemical localization data revealed that pCAL1a occurs in lysosome-like vesicles in all tissues, except anterior midgut, where a labelling considered to correspond to pCAL2 is found in large acidic granules being released by apocrine secretion. Putative pCAL2 was also detected in midgut contents, probably in the form of CAL2, the major luminal CAL, which was purified to homogeneity. A cladogram of insect CALs result in a monophyletic branch with lysosomal T. molitor enzymes and enzymes from five insect orders and in a polyphyletic array of coleopteran sequences, including digestive CALs from T. molitor. The data suggest that only Coleoptera have digestive CALs that may originate by gene duplication and independent evolution relative to the gene encoding the lysosomal enzyme.

  16. A new prenylated flavone from Artocarpus champeden inhibits the K(+)-dependent amino acid transport in Bombyx mori midgut.

    PubMed

    Parenti, P; Pizzigoni, A; Hanozet, G; Hakim, E H; Makmur, L; Achmad, S A; Giordana, B

    1998-03-17

    The effect of some flavonoids on the K(+)-dependent and K(+)-independent leucine uptake into brush border membrane vesicles from Bombyx mori larval midgut was investigated. Among the compounds tested, cyclochampedol, recently purified from Artocarpus champeden, was able to inhibit in micromolar range the leucine transport. The inhibition occurred both in the absence and in the presence of potassium and was not affected by leucine concentration. The apparent Ki was 0.25 mM. Cyclochampedol represents the first non-competitive inhibitor of an amino acid transport system in Lepidoptera. The relevance of this result is discussed.

  17. Seasonal Differences in Density But Similar Competitive Impact of Aedes albopictus (Skuse) on Aedes aegypti (L.) in Rio de Janeiro, Brazil

    PubMed Central

    Camara, Daniel Cardoso Portela; Codeço, Claudia Torres; Juliano, Steven A.; Lounibos, L. Philip; Riback, Thais Irene Souza; Pereira, Glaucio Rocha; Honorio, Nildimar Alves

    2016-01-01

    Previous studies have shown that the negative effects of density of Ae. albopictus on Ae. aegypti exceed those of Ae. aegypti on Ae. albopictus for population growth, adult size, survivorship, and developmental rate. This competitive superiority has been invoked to explain the displacement of Ae. aegypti by Ae. albopictus in the southeastern USA. In Brazil, these species coexist in many vegetated suburban and rural areas. We investigated a related, but less-well-studied question: do effects of Ae. albopictus on Ae. aegypti larval development and survival occur under field conditions at realistic densities across multiple seasons in Brazil? We conducted additive competition experiments in a vegetated area of Rio de Janeiro where these species coexist. We tested the hypothesis that Ae. aegypti (the focal species, at a fixed density) suffers negative effects on development and survivorship across a gradient of increasing densities of Ae. albopictus (the associate species) in three seasons. The results showed statistically significant effects of both season and larval density on Ae. aegypti survivorship, and significant effects of season on development rate, with no significant season-density interactions. Densities of Aedes larvae in these habitats differed among seasons by a factor of up to 7x. Overall, Spring was the most favorable season for Ae. aegypti survivorship and development. Results showed that under natural conditions the negative competitive effects of Ae. albopictus on Ae. aegypti were expressed primarily as lower survivorship. Coexistence between Ae. aegypti and Ae. albopictus in vegetated areas is likely affected by seasonal environmental differences, such as detrital resource levels or egg desiccation, which can influence competition between these species. Interactions between these Aedes are important in Brazil, where both species are well established and widely distributed and vector dengue, Zika and chikungunya viruses. PMID:27322537

  18. Seasonal Differences in Density But Similar Competitive Impact of Aedes albopictus (Skuse) on Aedes aegypti (L.) in Rio de Janeiro, Brazil.

    PubMed

    Camara, Daniel Cardoso Portela; Codeço, Claudia Torres; Juliano, Steven A; Lounibos, L Philip; Riback, Thais Irene Souza; Pereira, Glaucio Rocha; Honorio, Nildimar Alves

    2016-01-01

    Previous studies have shown that the negative effects of density of Ae. albopictus on Ae. aegypti exceed those of Ae. aegypti on Ae. albopictus for population growth, adult size, survivorship, and developmental rate. This competitive superiority has been invoked to explain the displacement of Ae. aegypti by Ae. albopictus in the southeastern USA. In Brazil, these species coexist in many vegetated suburban and rural areas. We investigated a related, but less-well-studied question: do effects of Ae. albopictus on Ae. aegypti larval development and survival occur under field conditions at realistic densities across multiple seasons in Brazil? We conducted additive competition experiments in a vegetated area of Rio de Janeiro where these species coexist. We tested the hypothesis that Ae. aegypti (the focal species, at a fixed density) suffers negative effects on development and survivorship across a gradient of increasing densities of Ae. albopictus (the associate species) in three seasons. The results showed statistically significant effects of both season and larval density on Ae. aegypti survivorship, and significant effects of season on development rate, with no significant season-density interactions. Densities of Aedes larvae in these habitats differed among seasons by a factor of up to 7x. Overall, Spring was the most favorable season for Ae. aegypti survivorship and development. Results showed that under natural conditions the negative competitive effects of Ae. albopictus on Ae. aegypti were expressed primarily as lower survivorship. Coexistence between Ae. aegypti and Ae. albopictus in vegetated areas is likely affected by seasonal environmental differences, such as detrital resource levels or egg desiccation, which can influence competition between these species. Interactions between these Aedes are important in Brazil, where both species are well established and widely distributed and vector dengue, Zika and chikungunya viruses. PMID:27322537

  19. Production of Infectious Dengue Virus in Aedes aegypti Is Dependent on the Ubiquitin Proteasome Pathway

    PubMed Central

    Choy, Milly M.; Sessions, October M.; Gubler, Duane J.; Ooi, Eng Eong

    2015-01-01

    Dengue virus (DENV) relies on host factors to complete its life cycle in its mosquito host for subsequent transmission to humans. DENV first establishes infection in the midgut of Aedes aegypti and spreads to various mosquito organs for lifelong infection. Curiously, studies have shown that infectious DENV titers peak and decrease thereafter in the midgut despite relatively stable viral genome levels. However, the mechanisms that regulate this decoupling of infectious virion production from viral RNA replication have never been determined. We show here that the ubiquitin proteasome pathway (UPP) plays an important role in regulating infectious DENV production. Using RNA interference studies, we show in vivo that knockdown of selected UPP components reduced infectious virus production without altering viral RNA replication in the midgut. Furthermore, this decoupling effect could also be observed after RNAi knockdown in the head/thorax of the mosquito, which otherwise showed direct correlation between infectious DENV titer and viral RNA levels. The dependence on the UPP for successful DENV production is further reinforced by the observed up-regulation of key UPP molecules upon DENV infection that overcome the relatively low expression of these genes after a blood meal. Collectively, our findings indicate an important role for the UPP in regulating DENV production in the mosquito vector. PMID:26566123

  20. Expression and light-triggered movement of rhodopsins in the larval visual system of mosquitoes

    PubMed Central

    Rocha, Manuel; Kimler, Kyle J.; Leming, Matthew T.; Hu, Xiaobang; Whaley, Michelle A.; O'Tousa, Joseph E.

    2015-01-01

    ABSTRACT During the larval stages, the visual system of the mosquito Aedes aegypti contains five stemmata, often referred to as larval ocelli, positioned laterally on each side of the larval head. Here we show that stemmata contain two photoreceptor types, distinguished by the expression of different rhodopsins. The rhodopsin Aaop3 (GPROP3) is expressed in the majority of the larval photoreceptors. There are two small clusters of photoreceptors located within the satellite and central stemmata that express the rhodopsin Aaop7 (GPROP7) instead of Aaop3. Electroretinogram analysis of transgenic Aaop7 Drosophila indicates that Aaop3 and Aaop7, both classified as long-wavelength rhodopsins, possess similar but not identical spectral properties. Light triggers an extensive translocation of Aaop3 from the photosensitive rhabdoms to the cytoplasmic compartment, whereas light-driven translocation of Aaop7 is limited. The results suggest that these photoreceptor cell types play distinct roles in larval vision. An additional component of the larval visual system is the adult compound eye, which starts to develop at the anterior face of the larval stemmata during the 1st instar stage. The photoreceptors of the developing compound eye show rhodopsin expression during the 4th larval instar stage, consistent with indications from previous reports that the adult compound eye contributes to larval and pupal visual capabilities. PMID:25750414

  1. Integrated control of the dengue vector Aedes aegypti in Liu-Chiu village, Ping-Tung County, Taiwan.

    PubMed

    Wang, C H; Chang, N T; Wu, H H; Ho, C M

    2000-06-01

    Because of an inadequate supply of potable water, villagers of Small Liu-Chiu Isle, Ping-Tung County, Taiwan, store water in containers supporting a large population of Aedes aegypti. In 1989-96, integrated control measures against Ae. aegypti were implemented on the basis of community participation. These measures included release of mosquito larvivorous fish in the drinking water storage facilities, application of larvicides to the water storage facilities in vegetable gardens, removal of discarded and unused containers and tires, improvement of household water storage facilities, and increase of potable water supply. Before implementation of the integrated control measures in 1988, 74% of the water-containing vessels were water storage facilities, and 24% of those were infested by Ae. aegypti. In 1989, the Breteau index for the entire island, indicating the average distribution density for larval Ae. aegypti, was 53.9, as compared to an index of 1.2 in 1996. In 4 villages located at the southwest and middle of the island, Ae. aegypti nearly became extinct because of the enthusiastic participation of the community. Before the implementation of integrated control, Ae. aegypti was the dominant species in containers both inside and outside the household, but after the integrated control, Aedes albopictus became predominant outside. PMID:10901632

  2. Temporal genetic stability of Stegomyia aegypti (= Aedes aegypti) populations.

    PubMed

    Gloria-Soria, A; Kellner, D A; Brown, J E; Gonzalez-Acosta, C; Kamgang, B; Lutwama, J; Powell, J R

    2016-06-01

    The mosquito Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is the primary vector of viruses that cause yellow fever, dengue and Chikungunya fever. In the absence of effective vaccines, the reduction of these diseases relies on vector control strategies. The success of these strategies is tightly linked to the population dynamics of target populations. In the present study, 14 collections from St. aegypti populations separated by periods of 1-13 years were analysed to determine their temporal genetic stability. Although temporal structure is discernible in most populations, the degree of temporal differentiation is dependent on the population and does not obscure the geographic structure of the various populations. The results suggest that performing detailed studies in the years prior to and after population reduction- or modification-based control interventions at each target field site may be useful in assessing the probability of success. PMID:26744174

  3. Temporal genetic stability of Stegomyia aegypti (= Aedes aegypti) populations.

    PubMed

    Gloria-Soria, A; Kellner, D A; Brown, J E; Gonzalez-Acosta, C; Kamgang, B; Lutwama, J; Powell, J R

    2016-06-01

    The mosquito Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is the primary vector of viruses that cause yellow fever, dengue and Chikungunya fever. In the absence of effective vaccines, the reduction of these diseases relies on vector control strategies. The success of these strategies is tightly linked to the population dynamics of target populations. In the present study, 14 collections from St. aegypti populations separated by periods of 1-13 years were analysed to determine their temporal genetic stability. Although temporal structure is discernible in most populations, the degree of temporal differentiation is dependent on the population and does not obscure the geographic structure of the various populations. The results suggest that performing detailed studies in the years prior to and after population reduction- or modification-based control interventions at each target field site may be useful in assessing the probability of success.

  4. Resident microbiota of the gypsy moth midgut harbors antibiotic resistance determinants.

    PubMed

    Allen, Heather K; Cloud-Hansen, Karen A; Wolinski, Joseph M; Guan, Changhui; Greene, Serena; Lu, Shyue; Boeyink, Mallory; Broderick, Nichole A; Raffa, Kenneth F; Handelsman, Jo

    2009-03-01

    Little is known about the significance of insects as environmental reservoirs of antibiotic-resistant bacteria. We characterized the antibiotic resistome of the microbial community in gypsy moth larval midguts by applying functional metagenomics to cultured isolates. The minimum inhibitory concentrations of 12 antibiotics were determined for 44 cultured isolates, and antibiotic resistance genes were selected from metagenomic libraries derived from DNA extracted from a pool of the isolates. Six unique clones were identified. Two were highly resistant to penicillin-type beta-lactams, two were moderately resistant to erythromycin, and two were moderately resistant to a range of antibiotics, including erythromycin, carbenicillin, and chloramphenicol. Sequence analysis predicted that the active genes encoded efflux pumps, a transcriptional activator of efflux pump protein expression, and an extended-spectrum class A beta-lactamase. Insect guts are a reservoir of antibiotic resistance genes with the potential for dissemination.

  5. Effect of Cymbopogon citratus (lemongrass) and Syzygium aromaticum (clove) oils on the morphology and mortality of Aedes aegypti and Anopheles dirus larvae.

    PubMed

    Soonwera, Mayura; Phasomkusolsil, Siriporn

    2016-04-01

    Cymbopogon citratus (lemongrass) and Syzygium aromaticum (clove) oils were evaluated to determine mortality rates, morphological aberrations, and persistence when used against third and fourth larval instars of Aedes aegypti and Anopheles dirus. The oils were evaluated at 1, 5, and 10 % concentrations in mixtures with soybean oil. Persistence of higher concentrations was measured over a period of 10 days. For Ae. aegypti, both plant oils caused various morphological aberrations to include deformed larvae, incomplete eclosion, white pupae, deformed pupae, dead normal pupae, and incomplete pupal eclosion. All of these aberrations led to larval mortality. In Ae. aegypti larvae, there were no significant differences in mortality at days 1, 5, and 10 or between third and fourth larval instar exposure. In An. dirus, morphological aberrations were rare and S. aromaticum oil was more effective in causing mortality among all larval stages. Both oils were equally effective at producing mortality on days 1, 5, and 10. Both oils had slightly increased LT50 rates from day 1 to day 10. In conclusion, both lemongrass and clove oils have significant effects on the immature stages of Ae. aegypti and An. dirus and could potentially be developed for use as larvicides. PMID:26796022

  6. Effect of Cymbopogon citratus (lemongrass) and Syzygium aromaticum (clove) oils on the morphology and mortality of Aedes aegypti and Anopheles dirus larvae.

    PubMed

    Soonwera, Mayura; Phasomkusolsil, Siriporn

    2016-04-01

    Cymbopogon citratus (lemongrass) and Syzygium aromaticum (clove) oils were evaluated to determine mortality rates, morphological aberrations, and persistence when used against third and fourth larval instars of Aedes aegypti and Anopheles dirus. The oils were evaluated at 1, 5, and 10 % concentrations in mixtures with soybean oil. Persistence of higher concentrations was measured over a period of 10 days. For Ae. aegypti, both plant oils caused various morphological aberrations to include deformed larvae, incomplete eclosion, white pupae, deformed pupae, dead normal pupae, and incomplete pupal eclosion. All of these aberrations led to larval mortality. In Ae. aegypti larvae, there were no significant differences in mortality at days 1, 5, and 10 or between third and fourth larval instar exposure. In An. dirus, morphological aberrations were rare and S. aromaticum oil was more effective in causing mortality among all larval stages. Both oils were equally effective at producing mortality on days 1, 5, and 10. Both oils had slightly increased LT50 rates from day 1 to day 10. In conclusion, both lemongrass and clove oils have significant effects on the immature stages of Ae. aegypti and An. dirus and could potentially be developed for use as larvicides.

  7. Mesocyclops longisetus effects on survivorship of Aedes aegypti immature stages in car tyres.

    PubMed

    Manrique-Saide, P; Ibáñez-Bernal, S; Delfín-González, H; Parra Tabla, V

    1998-10-01

    The effect of the introduction of the entomophagous copepod Mesocyclops longisetus (Acuacultura F.C.B. strain) on the survival of Aedes aegypti immature stages in car tyres was evaluated under semi-natural conditions in the municipality of Merida, Yucatan, Mexico. Life tables were constructed for the immature stages of the mosquito in the presence and absence of M. longisetus, and the survival data were compared using log-linear models. The data set was adjusted using the GLIM statistical package and the quality of adjustment was evaluated with a chi-squared test. Survivorship curves were constructed for each treatment. In the absence of M. longisetus, the survivorship of Ae. aegypti immature stages averaged 9%. The highest mortality rate was observed during the fourth larval instar (54%) and the resulting survival pattern corresponded to a type II survivorship curve. The mortality rate of Ae. aegypti first-instar larvae (fifty per tyre) increased more than 200-fold in the presence of M. longisetus (twenty per tyre) and the highest mortality was during the first two larval instars, where it reached 98.9%, with a resulting survivorship of 0.2%. Overall mortality was sixfold greater in the presence of the copepod than in its absence. The survival pattern of immature stages of Ae. aegypti in the presence of the copepod corresponded to a type III survivorship curve. As M. longisetus was so effective against Ae. aegypti immature stages in tyres under seminatural conditions, its long-term effectiveness should be evaluated under socially and ecologically realistic field conditions in Mexico. PMID:9824822

  8. Apoptosis-related genes control autophagy and influence DENV-2 infection in the mosquito vector, Aedes aegypti.

    PubMed

    Eng, Matthew W; van Zuylen, Madeleine N; Severson, David W

    2016-09-01

    The mosquito Aedes aegypti is the primary urban vector for dengue virus (DENV) worldwide. Insight into interactions occurring between host and pathogen is important in understanding what factors contribute to vector competence. However, many of the molecular mechanisms for vector competence remain unknown. Our previous global transcriptional analysis suggested that differential expression of apoptotic proteins is involved in determining refractoriness vs susceptibility to DENV-2 infection in Ae. aegypti females following a DENV-infected blood meal. To determine whether DENV-refractory Ae. aegypti showed more robust apoptosis upon infection, we compared numbers of apoptotic cells from midguts of refractory and susceptible strains and observed increased numbers of apoptotic cells in only the refractory strain upon DENV-2 infection. Thereafter, we manipulated apoptosis through dsRNA interference of the initiator caspase, Aedronc. Unexpectedly, dsAedronc-treated females showed both decreased frequency of disseminated infection and decreased virus titer in infected individuals. Insect caspases have also previously been identified as regulators of the cellular recycling process known as autophagy. We observed activation of autophagy in midgut and fat body tissues following a blood meal, as well as programmed activation of several apoptosis-related genes, including the effector caspase, Casps7. To determine whether autophagy was affected by caspase knockdown, we silenced Aedronc and Casps7, and observed reduced activation of autophagy upon silencing. Our results provide evidence that apoptosis-related genes are also involved in regulating autophagy, and that Aedronc may play an important role in DENV-2 infection success in Ae. aegypti, possibly through its regulation of autophagy. PMID:27418459

  9. Late-instar Behavior of Aedes aegypti (Diptera: Culicidae) Larvae in Different Thermal and Nutritive Environments.

    PubMed

    Reiskind, Michael H; Janairo, M Shawn

    2015-09-01

    The effects of temperature on ectotherm growth have been well documented. How temperature affects foraging behavior is less well explored, and has not been studied in larval mosquitoes. We hypothesized that temperature changes foraging behavior in the aquatic larval phase of the mosquito, Aedes aegypti L. Based on empirical results in other systems, we predicted that foraging effort would increase at higher temperatures in these insects. We tested this prediction over three temperature conditions at two food levels. We measured behaviors by video recording replicated cohorts of fourth-instar mosquitoes and assessing individual behavior and time budgets using an ethogram. We found both food level and temperature had significant impacts on larval foraging behavior, with more time spent actively foraging at low food levels and at low temperatures, and more occurrences of active foraging at both temperature extremes. These results are contrary to some of our predictions, but fit into theoretical responses to temperature based upon dynamic energy budget models.

  10. Late-instar Behavior of Aedes aegypti (Diptera: Culicidae) Larvae in Different Thermal and Nutritive Environments.

    PubMed

    Reiskind, Michael H; Janairo, M Shawn

    2015-09-01

    The effects of temperature on ectotherm growth have been well documented. How temperature affects foraging behavior is less well explored, and has not been studied in larval mosquitoes. We hypothesized that temperature changes foraging behavior in the aquatic larval phase of the mosquito, Aedes aegypti L. Based on empirical results in other systems, we predicted that foraging effort would increase at higher temperatures in these insects. We tested this prediction over three temperature conditions at two food levels. We measured behaviors by video recording replicated cohorts of fourth-instar mosquitoes and assessing individual behavior and time budgets using an ethogram. We found both food level and temperature had significant impacts on larval foraging behavior, with more time spent actively foraging at low food levels and at low temperatures, and more occurrences of active foraging at both temperature extremes. These results are contrary to some of our predictions, but fit into theoretical responses to temperature based upon dynamic energy budget models. PMID:26336228

  11. Dissemination and transmission of the E1-226V variant of chikungunya virus in Aedes albopictus are controlled at the midgut barrier level.

    PubMed

    Arias-Goeta, Camilo; Mousson, Laurence; Rougeon, François; Failloux, Anna-Bella

    2013-01-01

    Emergence of arboviruses could result from their ability to exploit new environments, for example a new host. This ability is facilitated by the high mutation rate occurring during viral genome replication. The last emergence of chikungunya in the Indian Ocean region corroborates this statement since a single viral mutation at the position 226 on the E1 glycoprotein (E1-A226V) was associated with enhanced transmission by the mosquito Aedes albopictus in regions where the major mosquito vector, Aedes aegypti, is absent.We used direct competition assays in vivo to dissect out the mechanisms underlying the selection of E1-226V by Ae. albopictus. When the original variant E1-226A and the newly emerged E1-226V were provided in the same blood-meal at equal titers to both species of mosquitoes, we found that the proportion of both variants was drastically different in the two mosquito species. Following ingestion of the infectious blood-meal, the E1-226V variant was preferentially selected in Ae. albopictus, whereas the E1-226A variant was sometimes favored in Ae. aegypti. Interestingly, when the two variants were introduced into the mosquitoes by intrathoracic inoculations, E1-226V was no longer favored for dissemination and transmission in Ae. albopictus, showing that the midgut barrier plays a key role in E1-226V selection.This study sheds light on the role of the midgut barrier in the selection of novel arbovirus emerging variants. We also bring new insight into how the pre-existing variant E1-226V was selected among other viral variants including E1-226A. Indeed the E1-226V variant present at low levels in natural viral populations could rapidly emerge after being selected in Ae. albopictus at the midgut barrier level. PMID:23437397

  12. Side Effects of Neem Oil on the Midgut Endocrine Cells of the Green Lacewing Ceraeochrysa claveri (Navás) (Neuroptera: Chrysopidae).

    PubMed

    Scudeler, E L; Santos, D C

    2014-04-01

    We described the ultrastructure of Ceraeochrysa claveri (Navás) midgut endocrine cells in larva, pupa, and adult, and evaluated the side effects of ingested neem oil, a botanical insecticide obtained from the seeds of the neem tree (Azadirachta indica), on these cells. During the larval period, C. claveri were fed (ad libitum) Diatraea saccharalis (F.) eggs treated with neem oil at concentrations of 0.5%, 1%, or 2%. Transmission electron microscopy showed that two subtypes of endocrine cells, namely granular and vesicular, occurred in the midgut epithelium during the three stages of the life cycle. Both cell types did not reach the midgut lumen and were positioned basally in the epithelium. The endocrine cells did not show extensive infoldings of the basal plasma membrane, and there were numerous secretory granules in the basal region of the cytoplasm. In the granular endocrine cells, the granules were completely filled with a dense matrix. In the vesicular endocrine cells, the main secretory products consisted of haloed vesicles. Ultrastructural examination indicated that only the granular endocrine cells exhibited signs of morphologic changes of cell injury present in all life cycle stages after the larvae were chronically exposed to neem oil by ingestion. The major cellular damage consisted of dilatation and vesiculation of the rough endoplasmic reticulum and the development of smooth endoplasmic reticulum and mitochondrial swelling. Our data suggest that cytotoxic effects on midgut endocrine cells can contribute to a generalized disruption of the physiological processes in this organ due to a general alteration of endocrine function.

  13. The midgut ultrastructure of the endoparasite Xenos vesparum (Rossi) (Insecta, Strepsiptera) during post-embryonic development and stable carbon isotopic analyses of the nutrient uptake.

    PubMed

    Giusti, Fabiola; Dallai, Luigi; Beani, Laura; Manfredini, Fabio; Dallai, Romano

    2007-06-01

    Females of the endoparasite Xenos vesparum (Strepsiptera, Stylopidae) may survive for months inside the host Polistes dominulus (Hymenoptera, Vespidae). The midgut structure and function in larval instars and neotenic females has been studied by light and electron microscope and by stable carbon isotopic technique. The 1st instar larva utilizes the yolk material contained in the gut lumen, whereas the subsequent larval instars are actively involved in nutrient uptake from the wasp hemolymph and storage in the adipocytes. At the end of the 4th instar, the neotenic female extrudes with its anterior region from the host; the midgut progressively degenerates following an autophagic cell death program. First the midgut epithelial cells accumulate lamellar bodies and then expel their nuclei into the gut lumen; the remnant gut consists of a thin epithelium devoid of nuclei but still provided with intercellular junctions. We fed the parasitized wasps with sugar from different sources (beet or cane), characterized by their distinctive carbon isotope compositions, and measured the bulk (13)C/(12)C ratios of both wasps and parasites. Female parasites developing inside the wasp hemocoel are able to absorb nutrients from the host but, after their extrusion, they stop incorporating nutrients and survive thanks to the adipocytes content. PMID:18089098

  14. Observations on the breeding habitats of Aedes aegypti in Calcutta following an episode of dengue haemorrhagic fever.

    PubMed

    Biswas, D; Dey, S; Dutta, R N; Hati, A K

    1993-01-01

    A year-long (Nov. 1990-Oct. 1991) search for Ae. aegypti larvae was made of all water containers in and around fixed 100 houses at Bowbazar area in Calcutta following an episode of DHF. Out of 10151 containers searched, 615 (6%) were positive. Masonry tanks were the major (64.2%) and preferred (17%) breeding sites of Ae. aegypti. Indoor containers (6.7%) were more conducive to breeding of the vector species than the outdoor ones (3%). Breteau index showing wide variation (25 in December '90 to '93 in August 1991) proved to be the best for measurement of density of larval population of Ae. aegypti and paralleled the fluctuation in both rainfall and humidity. Role of temperature was not pronounced. It was noted that cases of DHF occurred even with the lowest Breteau index in December.

  15. Dynamics of the "popcorn" Wolbachia infection in outbred Aedes aegypti informs prospects for mosquito vector control.

    PubMed

    Yeap, H L; Mee, P; Walker, T; Weeks, A R; O'Neill, S L; Johnson, P; Ritchie, S A; Richardson, K M; Doig, C; Endersby, N M; Hoffmann, A A

    2011-02-01

    Forty percent of the world's population is at risk of contracting dengue virus, which produces dengue fever with a potentially fatal hemorrhagic form. The wMelPop Wolbachia infection of Drosophila melanogaster reduces life span and interferes with viral transmission when introduced into the mosquito Aedes aegypti, the primary vector of dengue virus. Wolbachia has been proposed as an agent for preventing transmission of dengue virus. Population invasion by Wolbachia depends on levels of cytoplasmic incompatibility, fitness effects, and maternal transmission. Here we characterized these traits in an outbred genetic background of a potential target population of Ae. aegypti using two crossing schemes. Cytoplasmic incompatibility was strong in this background, and the maternal transmission rate of Wolbachia was high. The infection substantially reduced longevity of infected adult females, regardless of whether adults came from larvae cultured under high or low levels of nutrition or density. The infection reduced the viability of diapausing and nondiapausing eggs. Viability was particularly low when eggs were laid by older females and when diapausing eggs had been stored for a few weeks. The infection affected mosquito larval development time and adult body size under different larval nutrition levels and densities. The results were used to assess the potential for wMelPop-CLA to invade natural populations of Ae. aegypti and to develop recommendations for the maintenance of fitness in infected mosquitoes that need to compete against field insects. PMID:21135075

  16. Aedes (Stegomyia) aegypti in the continental United States: a vector at the cool margin of its geographic range.

    PubMed

    Eisen, Lars; Moore, Chester G

    2013-05-01

    After more than a half century without recognized local dengue outbreaks in the continental United States, there were recent outbreaks of autochthonous dengue in the southern parts of Texas (2004-2005) and Florida (2009-2011). This dengue reemergence has provoked interest in the extent of the future threat posed by the yellow fever mosquito, Aedes (Stegomyia) aegypti (L.), the primary vector of dengue and yellow fever viruses in urban settings, to human health in the continental United States. Ae. aegypti is an intriguing example of a vector species that not only occurs in the southernmost portions of the eastern United States today but also is incriminated as the likely primary vector in historical outbreaks of yellow fever as far north as New York, Philadelphia, and Boston, from the 1690s to the 1820s. For vector species with geographic ranges limited, in part, by low temperature and cool range margins occurring in the southern part of the continental United States, as is currently the case for Ae. aegypti, it is tempting to speculate that climate warming may result in a northward range expansion (similar to that seen for Ixodes tick vectors of Lyme borreliosis spirochetes in Scandinavia and southern Canada in recent decades). Although there is no doubt that climate conditions directly impact many aspects of the life history of Ae. aegypti, this mosquito also is closely linked to the human environment and directly influenced by the availability of water-holding containers for oviposition and larval development. Competition with other container-inhabiting mosquito species, particularly Aedes (Stegomyia) albopictus (Skuse), also may impact the presence and local abundance of Ae. aegypti. Field-based studies that focus solely on the impact of weather or climate factors on the presence and abundance of Ae. aegypti, including assessments of the potential impact of climate warming on the mosquito's future range and abundance, do not consider the potential confounding

  17. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase.

    PubMed

    Mazzalupo, Stacy; Isoe, Jun; Belloni, Virginia; Scaraffia, Patricia Y

    2016-01-01

    To better understand the mechanisms responsible for the success of female mosquitoes in their disposal of excess nitrogen, we investigated the role of alanine aminotransferase (ALAT) in blood-fed Aedes aegypti. Transcript and protein levels from the 2 ALAT genes were analyzed in sucrose- and blood-fed A. aegypti tissues. ALAT1 and ALAT2 exhibit distinct expression patterns in tissues during the first gonotrophic cycle. Injection of female mosquitoes with either double-stranded RNA (dsRNA)-ALAT1 or dsRNA ALAT2 significantly decreased mRNA and protein levels of ALAT1 or ALAT2 in fat body, thorax, and Malpighian tubules compared with dsRNA firefly luciferase-injected control mosquitoes. The silencing of either A. aegypti ALAT1 or ALAT2 caused unexpected phenotypes such as a delay in blood digestion, a massive accumulation of uric acid in the midgut posterior region, and a significant decrease of nitrogen waste excretion during the first 48 h after blood feeding. Concurrently, the expression of genes encoding xanthine dehydrogenase and ammonia transporter (Rhesus 50 glycoprotein) were significantly increased in tissues of both ALAT1- and ALAT2-deficient females. Moreover, perturbation of ALAT1 and ALAT2 in the female mosquitoes delayed oviposition and reduced egg production. These novel findings underscore the efficient mechanisms that blood-fed mosquitoes use to avoid ammonia toxicity and free radical damage.-Mazzalupo, S., Isoe, J., Belloni, V., Scaraffia, P. Y. Effective disposal of nitrogen waste in blood-fed Aedes aegypti mosquitoes requires alanine aminotransferase.

  18. A lethal ovitrap-based mass trapping scheme for dengue control in Australia: II. Impact on populations of the mosquito Aedes aegypti.

    PubMed

    Rapley, L P; Johnson, P H; Williams, C R; Silcock, R M; Larkman, M; Long, S A; Russell, R C; Ritchie, S A

    2009-12-01

    In Cairns, Australia, the impacts on Aedes aegypti L. (Diptera: Culicidae) populations of two types of 'lure & kill' (L&K) lethal ovitraps (LOs), the standard lethal ovitrap (SLO) and the biodegradable lethal ovitrap (BLO) were measured during three mass-trapping interventions. To assess the efficacy of the SLO, two interventions (one dry season and one wet season) were conducted in three discrete areas, each lasting 4 weeks, with the following treatments: (i) SLOs (>200 traps, approximately 4/premise), BG-sentinel traps (BGSs; approximately 15, 1/premise) and larval control (container reduction and methoprene treatment) and (ii) larval control alone, and (iii) untreated control. Female Ae. aegypti populations were monitored for 4 weeks pre- and post-treatment in all three areas using BGSs and sticky ovitraps (SOs) or non-lethal regular ovitraps (ROs). In the dry season, 206 SLOs and 15 BGSs set at 54 and 15 houses, respectively, caught and killed an estimated 419 and 73 female Ae. aegypti, respectively. No significant decrease in collection size of female Ae. aegypti could be attributed to the treatments. In the wet season, 243 SLOs and 15 BGSs killed approximately 993 and 119 female Ae. aegypti, respectively. The mean number of female Ae. aegypti collected after 4 weeks with SOs and BGSs was significantly less than the control (LSD post-hoc test). The third mass-trapping intervention was conducted using the BLO during the wet season in Cairns. For this trial, three treatment areas were each provided with BLOs (>500, approximately 4/premise) plus larval control, and an untreated control area was designated. Adult female Ae. aegypti were collected for 4 weeks pre- and post-treatment using 15 BGSs and 20 SOs. During this period, 53.2% of BLOs contained a total of 6654 Ae. aegypti eggs. Over the intervention period, collections of Ae. aegypti in the treatment areas were significantly less than in the control area for BGSs but not SOs. An influx of relatively large

  19. Environmental and Genetic Factors Determine Whether the Mosquito Aedes aegypti Lays Eggs without a Blood Meal

    PubMed Central

    Ariani, Cristina V.; Smith, Sophia C. L.; Osei-Poku, Jewelna; Short, Katherine; Juneja, Punita; Jiggins, Francis M.

    2015-01-01

    Some mosquito strains or species are able to lay eggs without taking a blood meal, a trait named autogeny. This may allow populations to persist through times or places where vertebrate hosts are scarce. Autogenous egg production is highly dependent on the environment in some species, but the ideal conditions for its expression in Aedes aegypti mosquitoes are unknown. We found that 3.2% of females in a population of Ae. aegypti from Kenya were autogenous. Autogeny was strongly influenced by temperature, with many more eggs laid at 28°C compared with 22°C. Good nutrition in larval stages and feeding on higher concentrations of sugar solution during the adult stage both result in more autogenous eggs being produced. The trait also has a genetic basis, as not all Ae. aegypti genotypes can lay autogenously. We conclude that Ae. aegypti requires a favorable environment and a suitable genotype to be able to lay eggs without a blood meal. PMID:25646251

  20. The Dengue Virus Mosquito Vector Aedes aegypti at High Elevation in México

    PubMed Central

    Lozano-Fuentes, Saul; Hayden, Mary H.; Welsh-Rodriguez, Carlos; Ochoa-Martinez, Carolina; Tapia-Santos, Berenice; Kobylinski, Kevin C.; Uejio, Christopher K.; Zielinski-Gutierrez, Emily; Monache, Luca Delle; Monaghan, Andrew J.; Steinhoff, Daniel F.; Eisen, Lars

    2012-01-01

    México has cities (e.g., México City and Puebla City) located at elevations > 2,000 m and above the elevation ceiling below which local climates allow the dengue virus mosquito vector Aedes aegypti to proliferate. Climate warming could raise this ceiling and place high-elevation cities at risk for dengue virus transmission. To assess the elevation ceiling for Ae. aegypti and determine the potential for using weather/climate parameters to predict mosquito abundance, we surveyed 12 communities along an elevation/climate gradient from Veracruz City (sea level) to Puebla City (∼2,100 m). Ae. aegypti was commonly encountered up to 1,700 m and present but rare from 1,700 to 2,130 m. This finding extends the known elevation range in México by > 300 m. Mosquito abundance was correlated with weather parameters, including temperature indices. Potential larval development sites were abundant in Puebla City and other high-elevation communities, suggesting that Ae. aegypti could proliferate should the climate become warmer. PMID:22987656

  1. Larvicidal activity against Aedes aegypti of pacharin from Bauhinia acuruana.

    PubMed

    da Silva Góis, Roberto Wagner; de Sousa, Leôncio Mesquita; Santiago, Gilvandete Maria Pinheiro; Romero, Nirla Rodrigues; Lemos, Telma Leda Gomes; Arriaga, Angela Martha Campos; Braz-Filho, Raimundo

    2013-07-01

    The aim of the present study was to evaluate the activity of pacharin isolated from the ethanol extract from roots of Bauhinia acuruana on third-instar larvae of Aedes aegypti Linn. (Diptera: Culicidae). The crude ethanol extract showed larvicidal activity at the concentration of 500 μg/mL. Given this larvicidal activity, this extract was submitted to chromatographic fractionation on a silica gel column eluted with n-hexane, dichloromethane, ethyl ether, ethyl acetate, and methanol in order to isolate the active compound(s). Pacharin, obtained in pure form from fraction eluted with ethyl ether, was evaluated for their larvicidal effects against A. aegypti. In these bioassays, the larvae were exposed at concentrations of 500, 250, 100, 50, and 25 μg/mL of the crude ethanol extract or pacharin. After 24 h, the number of dead larvae was counted and the LC₅₀ values for larval mortality were calculated. Pacharin showed LC50 value of 78.9 ± 1.8 μg/mL. The structure of isolated compound was identified on the basis of their spectral data (IR, 1D- and 2D-NMR) and by comparison with literature spectral data. The results indicate pacharin as a potential natural larvicide.

  2. Bacterial Infection and Immune Responses in Lutzomyia longipalpis Sand Fly Larvae Midgut.

    PubMed

    Heerman, Matthew; Weng, Ju-Lin; Hurwitz, Ivy; Durvasula, Ravi; Ramalho-Ortigao, Marcelo

    2015-01-01

    The midgut microbial community in insect vectors of disease is crucial for an effective immune response against infection with various human and animal pathogens. Depending on the aspects of their development, insects can acquire microbes present in soil, water, and plants. Sand flies are major vectors of leishmaniasis, and shown to harbor a wide variety of Gram-negative and Gram-positive bacteria. Sand fly larval stages acquire microorganisms from the soil, and the abundance and distribution of these microorganisms may vary depending on the sand fly species or the breeding site. Here, we assess the distribution of two bacteria commonly found within the gut of sand flies, Pantoea agglomerans and Bacillus subtilis. We demonstrate that these bacteria are able to differentially infect the larval digestive tract, and regulate the immune response in sand fly larvae. Moreover, bacterial distribution, and likely the ability to colonize the gut, is driven, at least in part, by a gradient of pH present in the gut.

  3. Larvicidal and pupicidal activities of essential oils from Zingiberaceae plants against Aedes aegypti (Linn.) and Culex quinquefasciatus say mosquitoes.

    PubMed

    Phukerd, Ubol; Soonwera, Mayura

    2013-09-01

    We conducted this study to investigate the efficacy of herbal essential oils from 12 species of Zingiberaceae plants to determine their larvicidal and pupicidal activity against fourth instar larvae and pupae of Aedes aegypti and Culex quinquefasciatus mosquitoes. Probit analysis was used to analyze the data. Larval mortality was recorded at 1, 5, 10, 15, 30 and 60 minutes and 24 hours. Pupal mortality was recorded at 15 and 30 minutes and 1, 3, 6, 12, 24 and 48 hours. All the essential oils tested showed larvicidal activity. Zingiber cassumunar and Amomum biflorum oils proved to have the greatest activity against Ae. aegypti larvae with LT50 of 1.4 minutes and 100% mortality at 5 and 10 minutes, respectively. Boesenbergia rotunda, Curcuma zedoaria and Hedychium coronarium essential oils had activity against Cx. quinquefasciatus larvae with LT50 of 1.7 minutes and 100% mortality at 10 minutes, 5 minutes and 15 minutes, respectively. All the herbal essential oils tested resulted in 100% mortality against Ae. aegypti and Cx. quinquefasciatus larvae at 60 minutes and 30 minutes, respectively. Ae. aegypti and Cx. quinquefasciatus pupae were susceptible to Z. ottensii oil (LT50 of 0.2 hour) and Z. zerumbet oil (LT50 of 0.6 hour) and had pupicidal activity with 100% mortality at 6 and 3 hours, respectively. All the essential oils test had pupicidal activity against Ae. aegypti and Cx. quinquefasciatus by inducing 100% mortality at 48 hours. PMID:24437311

  4. Effect of Moringa oleifera lectin on development and mortality of Aedes aegypti larvae.

    PubMed

    Coelho, Juliene S; Santos, Nataly D L; Napoleão, Thiago H; Gomes, Francis S; Ferreira, Rodrigo S; Zingali, Russolina B; Coelho, Luana C B B; Leite, Sônia P; Navarro, Daniela M A F; Paiva, Patrícia M G

    2009-11-01

    Aedes aegypti larvae have developed tolerance to many insecticides used for mosquito control. Moringa oleifera seeds contain a water-soluble lectin (WSMoL) and this paper reports the effect of M. oleifera seed extracts (MoE(1-15)) and WSMoL on development and survival of A. aegypti larvae. WSMoL peptide from in-gel trypsin digestion is also described. MoE(1-15) showed hemagglutinating activity and WSMoL had similarity with flocculating proteins from M. oleifera seeds. MoE(1) and MoE(3) delayed larval development which stopped in the third instar (L3) in MoE(6) and MoE(15). Significant (p<0.0001) larval mortality was only detected in MoE(15). Native WSMoL showed larvicidal activity (LC(50) 0.197 mg mL(-1)) and heated lectin, without hemagglutinating activity, did not kill fourth instar (L4) larvae. Optical microscopy showed that live L4 from MoE(1) presented underlying epithelium, increased gut lumen and hypertrophic segments; dead L4 from WSMoL were absent of underlying epithelium, had increased gut lumen and hypertrophic segments. The presence of hemagglutinating activity in the extracts suggests that soluble lectin promotes the delay of larval development and mortality; furthermore, the absence of larvicidal activity in heat-denatured WSMoL strengthens the involvement of lectin in this activity mechanism. PMID:19747711

  5. Breeding Sites of Aedes aegypti: Potential Dengue Vectors in Dire Dawa, East Ethiopia

    PubMed Central

    Getachew, Dejene; Tekie, Habte; Gebre-Michael, Teshome; Balkew, Meshesha; Mesfin, Akalu

    2015-01-01

    Background and Objectives. Entomological survey was carried out from May-June to September-October 2014 to investigate the presence of dengue vectors in discarded tires and artificial water containers in houses and peridomestic areas. Methods. A cross-sectional immature stage survey was done indoors and outdoors in 301 houses. Mosquito larval sampling was conducted using pipette or dipper depending on container types. Larvae were identified morphologically and larval indices were also calculated. Results. A total of 750 containers were inspected, and of these 405 were positive for mosquito larvae. A total of 1,873 larvae were collected and morphologically identified as Aedes aegypti (n = 1580: 84.4%) and Culex (n = 293: 15.6%). The larval indices, house index, container index, and breteau index, varied from 33.3 to 86.2, from 23.2 to 73.9, and from 56.5 to 188.9, respectively. Conclusion. Aedes aegypti is breeding in a wide range of artificial containers. To control these mosquitoes, the integration of different methods should be taken into consideration. PMID:26435712

  6. The design of a community-based health education intervention for the control of Aedes aegypti.

    PubMed

    Lloyd, L S; Winch, P; Ortega-Canto, J; Kendall, C

    1994-04-01

    This report describes the process used to develop locally appropriate educational materials and to implement the education component of a community-based Aedes aegypti control program in Merida, Yucatan, Mexico. The process is broken into five stages: formative research, developing recommendations for behavior change, development of educational messages, development and production of educational materials, and distribution of the materials. Appropriate terminology and taxonomies for dengue were obtained from open in-depth interviews; baseline data from a knowledge, beliefs, and practices questionnaire served to confirm this information. A larval survey of house lots was carried out to identify the Ae. aegypti larval production sites found on individual house lots. This enabled the program to target the most important larval habitats. Community groups were organized to work on the development of messages and production of the educational materials to be used. The education intervention was successful in stimulating changes in both knowledge and behavior, which were measured in the evaluations of the intervention. To be successful, community-based strategies must be flexible and adapted to the local setting because of ecologic, cultural, and social differences between localities.

  7. Surveillance of Aedes aegypti: Comparison of House Index with Four Alternative Traps

    PubMed Central

    Codeço, Claudia T.; Lima, Arthur W. S.; Araújo, Simone C.; Lima, José Bento P.; Maciel-de-Freitas, Rafael; Honório, Nildimar A.; Galardo, Allan K. R.; Braga, Ima A.; Coelho, Giovanini E.; Valle, Denise

    2015-01-01

    Introduction The mosquito Aedes aegypti, vector of dengue, chikungunya and yellow fever viruses, is an important target of vector control programs in tropical countries. Most mosquito surveillance programs are still based on the traditional household larval surveys, despite the availability of new trapping devices. We report the results of a multicentric entomological survey using four types of traps, besides the larval survey, to compare the entomological indices generated by these different surveillance tools in terms of their sensitivity to detect mosquito density variation. Methods The study was conducted in five mid-sized cities, representing variations of tropical climate regimens. Surveillance schemes using traps for adults (BG-Sentinel, Adultrap and MosquiTRAP) or eggs (ovitraps) were applied monthly to three 1 km2 areas per city. Simultaneously, larval surveys were performed. Trap positivity and density indices in each area were calculated and regressed against meteorological variables to characterize the seasonal pattern of mosquito infestation in all cities, as measured by each of the four traps. Results The House Index was consistently low in most cities, with median always 0. Traps rarely produced null indices, pointing to their greater sensitivity in detecting the presence of Ae. aegypti in comparison to the larval survey. Trap positivity indices tend to plateau at high mosquito densities. Despite this, both indices, positivity and density, agreed on the seasonality of mosquito abundance in all cities. Mosquito seasonality associated preferentially with temperature than with precipitation even in areas where temperature variation is small. Conclusions All investigated traps performed better than the House Index in measuring the seasonal variation in mosquito abundance and should be considered as complements or alternatives to larval surveys. Choice between traps should further consider differences of cost and ease-of-use. PMID:25668559

  8. Toxicity studies for indigenous Bacillus thuringiensis isolates from Malang city, East Java on Aedes aegypti larvae

    PubMed Central

    Gama, Zulfaidah Penata; Nakagoshi, Nobukazu; Suharjono; Setyowati, Faridah

    2013-01-01

    Objective To investigate the toxicity of indigenous Bacillus thuringiensis (B. thuringiensis)isolates from Malang City for controlling Aedes aegypti (Ae. aegypti) larvae. Methods Soil samples were taken from Purwantoro and Sawojajar sub-districts. Bacterial isolation was performed using B. thuringiensis selective media. Phenotypic characteristics of the isolates were obtained with the simple matching method. The growth and prevalence of spores were determined by the Total Plate Count method, and toxicity tests were also performed on the third instar larval stage of Ae. aegypti. The percentage of larval mortality was analysed using probit regression. The LC50 was analysed by ANOVA, and the Tukey HSD interval was 95%. Results Among the 33 selected bacterial isolates, six were obtained (PWR4-31, PWR4-32, SWJ4-2b, SWJ4-4b, SWJ-4k and SWJ5-1) that had a similar phenotype to reference B. thuringiensis. Based on the dendrogram, all of the bacterial isolates were 71% similar. Three isolates that had a higher prevalence of reference B. thuringiensis were PWR4-32, SWJ4-4b and SW5-1, of which the spore prevalence was 52.44%, 23.59%, 34.46%, respectively. These three indigenous isolates from Malang City successfully killed Ae. aegypti larvae. The PWR4-32 isolates were the most effective at killing the larvae. Conclusions Six indigenous B. thuringiensis isolates among the 33 bacterial isolates found in the Sawojajar and Purwantoro sub-districts were toxic to the third instar larvae of Ae. aegypti. The PWR4-32 isolates were identical to the reference B. thuringiensis and had 88% phenotype similarity. The PWR4-32 isolates had the highest spore prevalence (52.44%), and the early stationary phase occurred at 36 h. The PWR4-32 isolates were the most effective at killing Ae. aegypti larvae (LC50-72 h=2.3×108 cells/mL). PMID:23593589

  9. Surveillance and control of Aedes aegypti in epidemic areas of Taiwan.

    PubMed

    Lin, T H

    1994-12-01

    Aedes aegypti is the main, if not the only, vector of dengue fever in Taiwan. The dengue epidemics that have occurred in Taiwan correlate with the distribution of Aedes aegypti which is limited to south of the Tropic of Cancer. During the 1987 outbreak of dengue fever in Taiwan, the average larval density for the months July-December in the five cities and counties of southern Taiwan was 2,284 larvae per 100 households. After control measures were taken, the average annual larval density in the years from 1988 to 1993 declined to 1,580, 671, 442, 178, 110, and 88 larvae per 100 households, respectively. During 1987-1988, the number of confirmed cases and the Breteau index of Aedes aegypti showed an obvious positive relationship (r = 0.74) in the most heavily infected 25 cities and towns. Our Institute has conducted eight training courses since 1989 for 176 health workers who serve in their respective areas as local scouts for monitoring Aedes larval density. The number of cities and towns surveyed by them in the years 1990-1993 was 116, 149, 254, and 156, respectively. The number of households covered by space spraying with permethrin was 43, 183 in 1991, 11,186 in 1992 and 4,856 in 1993. Residual spraying with alphacypermethrin was applied to houses in areas where the Breteau index was above 35. The number of houses treated in the years 1990-1993 was 4,735, 32,279, 33,726 and 17,848, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Evaluation of Location-Specific Predictions by a Detailed Simulation Model of Aedes aegypti Populations

    PubMed Central

    Legros, Mathieu; Magori, Krisztian; Morrison, Amy C.; Xu, Chonggang; Scott, Thomas W.; Lloyd, Alun L.; Gould, Fred

    2011-01-01

    Background Skeeter Buster is a stochastic, spatially explicit simulation model of Aedes aegypti populations, designed to predict the outcome of vector population control methods. In this study, we apply the model to two specific locations, the cities of Iquitos, Peru, and Buenos Aires, Argentina. These two sites differ in the amount of field data that is available for location-specific customization. By comparing output from Skeeter Buster to field observations in these two cases we evaluate population dynamics predictions by Skeeter Buster with varying degrees of customization. Methodology/Principal Findings Skeeter Buster was customized to the Iquitos location by simulating the layout of houses and the associated distribution of water-holding containers, based on extensive surveys of Ae. aegypti populations and larval habitats that have been conducted in Iquitos for over 10 years. The model is calibrated by adjusting the food input into various types of containers to match their observed pupal productivity in the field. We contrast the output of this customized model to the data collected from the natural population, comparing pupal numbers and spatial distribution of pupae in the population. Our results show that Skeeter Buster replicates specific population dynamics and spatial structure of Ae. aegypti in Iquitos. We then show how Skeeter Buster can be customized for Buenos Aires, where we only had Ae. aegypti abundance data that was averaged across all locations. In the Argentina case Skeeter Buster provides a satisfactory simulation of temporal population dynamics across seasons. Conclusions This model can provide a faithful description of Ae. aegypti populations, through a process of location-specific customization that is contingent on the amount of data available from field collections. We discuss limitations presented by some specific components of the model such as the description of food dynamics and challenges that these limitations bring to model

  11. Workbook on Identification of Aedes Aegypti Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

    This self-instructional booklet is designed to enable yellow fever control workers to identify the larvae of "Aedes aegypti." The morphological features of mosquito larvae are illustrated in this partially programed text, and the distinguishing features of "A. aegypti" indicated. A glossary is included. (AL)

  12. Host hemolymph proteins and protein digestion in larval Habrobracon hebetor (Hymenoptera: braconidae).

    PubMed

    Baker, J E; Fabrick, J A

    2000-10-01

    Host plasma proteins and protein digestion in larval parasitoids were studied during trophic interactions of the ectoparasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae), with a host, larvae of the Indianmeal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). We could detect no apparent differences in host hemolymph protein patterns up to 72 h after paralysation and/or parasitization by H. hebetor. A 190 kDa putative apolipophorin I present in host hemolymph could not be detected in the midguts of feeding H. hebetor larvae indicating that it is rapidly digested. The major 60 kDa storage proteins (putative hexamerins) in host hemolymph were detected in the parasitoid midgut and were completely digested 24 h after cessation of feeding and the beginning of cocoon formation. Host hemolymph had a pH of about 6.4. The pH optima of the midgut proteinases in the larval parasitoid were in the alkaline region, but midgut fluid in feeding parasitoid larvae was about pH 6. 8. Based on enzyme activity against selected artificial proteinase substrates including azocasein, N-alpha-benzoyl-L-Arg p-nitroanilide (BApNA), succinyl-Ala-Ala-Pro-Phe p-nitroanilide (SAAPFpNA), succinyl-Ala-Ala-Pro-Leu p-nitroanilide (SAAPLpNA), and inhibition by selected proteinase inhibitors, serine proteinases appear to be the predominant class of enzymes involved in protein digestion in the midguts of H. hebetor. There is also an active aminopeptidase (LpNA) associated with the microsomal fraction of midgut preparations. There was no evidence for preoral digestion or ingestion of proteinases from host hemolymph by the parasitoid larva. There was a very active BApNAase in the soluble fraction of midgut extracts. This activity increased on a per midgut basis up to 24 h after the beginning of cocoon formation but decreased rapidly by 48 h. Two major (P1 and P3) and several minor proteinases were detected in midgut extracts of H. hebetor analysed with gelatin zymograms. The apparent

  13. Larvicidal & ovicidal efficacy of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) against Anopheles stephensi Liston & Aedes aegypti Linn. (Diptera: Culicidae)

    PubMed Central

    Govindarajan, M.; Rajeswary, M.; Sivakumar, R.

    2013-01-01

    Background & objectives: In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant Pithecellobium dulce against the mosquito vectors, Anopheles stephensi and Aedes aegypti (Diptera: Culicidae). Methods: Larvicidal activity of P. dulce plant extracts was studied in the range of 60 to 450 mg/l against early third instar larvae of An. stephensi and Ae. aegypti in the laboratory. The larval mortality was observed after 24 h of exposure. The ovicidal activity was determined against An. stephensi and Ae. aegypti to various concentrations ranging from 100 to 750 mg/l under the laboratory conditions. Mean per cent hatchability of the eggs were observed after 48 h post treatment. Results: All leaf and seed extracts showed moderate larvicidal and ovicidal effects; however, the highest larval mortality was found in methanol extract of leaf of P. dulce against the larvae of An. stephensi and Ae. aegypti with the LC50 and LC90 values 145.43, 155.78 mg/l and 251.23, 279.73 mg/l, respectively. The per cent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. Zero hatchability was observed at 400 mg/l for leaf methanol extract and 625 mg/l for seed methanol extract of P. dulce against An. stephensi and Ae. aegypti, respectively. Compared to leaf extracts, seed extracts have low potency against the two mosquitoes. Interpretation & conclusions: The present results suggest that the leaf and seed extracts of P. dulce have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. PMID:24056567

  14. Vector competence of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) for DEN2-43 and New Guinea C virus strains of dengue 2 virus.

    PubMed

    Guo, Xiao-Xia; Zhu, Xiao-Juan; Li, Chun-Xiao; Dong, Yan-De; Zhang, Ying-Mei; Xing, Dan; Xue, Rui-De; Qin, Cheng-Feng; Zhao, Tong-Yan

    2013-12-01

    The vector competence of Aedes albopictus and Aedes aegypti with regard to DEN2-43 and New Guinea C (NGC) virus strains of Dengue 2 viruses was assessed and compared. The infection and dissemination rate and distribution of DEN2-43 antigens in orally infected Ae. albopictus was investigated using the reverse transcription polymerase chain reaction and an indirect immunofluorescence assay. To better understand the initial infection, dissemination and transmission of these viral strains in vector mosquitoes, Ae. albopoictus and Ae. aegypti were fed an artificial blood meal containing either the DEN2-43 or NGC strain. There was no significant difference in the infection and dissemination rates of DEN2-43 and NGC virus strains in Ae. albopictus, however, Ae. aegypti was more susceptible to infection by NGC than DEN2-43 vrius strain. Ae. albopictus mosquitoes infected with the NGC strain developed a higher percentage of midgut infections than those infected with the DEN2-43 strain (t=2.893, df=7, P=0.024). Approximately 26.7% of midgut samples were positive for the NGC antigen 5 days after infection, and 80% of mosquitoes had infected midgets after 15 days. The NGC antigen first became evident in mosquito salivary glands on Day 5, and 40% of mosquitoes had infected salivary by Day 9. In contrast, the DEN2-43 antigen first became evident in salivary glands on Day 7. The infection rate of NGC and DEN2-43 virus strains in salivary glands were similar. These results indicate that Ae. albopictus and Ae. aegypti are moderately competent vectors for the DEN2-43 virus, which could provide basic data for the epidemiology study of dengue fever in China.

  15. Forces driven by morphogenesis modulate Twist Expression to determine Anterior Mid-gut Differentiation in Drosophila embryos

    NASA Astrophysics Data System (ADS)

    Farge, Emmanuel

    2008-03-01

    By combining magnetic tweezers to in vivo laser ablation, we locally manipulate Drosophila embryonic tissues with physiologically relevant forces. We demonstrate that high level of Twist expression in the stomodeal primordium is mechanically induced in response to compression by the 60±20 nN force developed during germ-band extension (GBE). We find that this force triggers the junctional release and nuclear translocation of Armadillo involved in Twist mechanical induction in the stomodeum in a Src42A dependent way. Finally, stomodeal-specific RNAi-mediated silencing of Twist during compression impairs the differentiation of midgut cells, as revealed by strong defects in Dve expression and abnormal larval lethality. Thus, mechanical induction of Twist overexpression in stomodeal cells is necessary for subsequent midgut differentiation. In collaboration with Nicolas Desprat, Willy Supatto, and Philippe-Alexandre Pouille, MGDET, UMR168 CNRS, Institut Curie11 rue Pierre et Marie Curie, F-75005, Paris, France; and Emmanuel Beaurepaire, LOB, Ecole Polytechnique, CNRS and INSERM U 696, 91128 Palaiseau, France.

  16. Hot temperatures can force delayed mosquito outbreaks via sequential changes in Aedes aegypti demographic parameters in autocorrelated environments.

    PubMed

    Chaves, Luis Fernando; Scott, Thomas W; Morrison, Amy C; Takada, Takenori

    2014-01-01

    Aedes aegypti L. (Diptera: Culicidae) is a common pantropical urban mosquito, vector of dengue, Yellow Fever and chikungunya viruses. Studies have shown Ae. aegypti abundance to be associated with environmental fluctuations, revealing patterns such as the occurrence of delayed mosquito outbreaks, i.e., sudden extraordinary increases in mosquito abundance following transient extreme high temperatures. Here, we use a two-stage (larvae and adults) matrix model to propose a mechanism for environmental signal canalization into demographic parameters of Ae. aegypti that could explain delayed high temperature induced mosquito outbreaks. We performed model simulations using parameters estimated from a weekly time series from Thailand, assuming either independent or autocorrelated environments. For autocorrelated environments, we found that long delays in the association between the onset of "hot" environments and mosquito outbreaks (10 weeks, as observed in Thailand) can be generated when "hot" environments sequentially trigger a larval survival decrease and over-compensatory fecundity increase, which lasts for the whole "hot" period, in conjunction with a larval survival increase followed by a fecundity decrease when the environment returns to "normal". This result was not observed for independent environments. Finally, we discuss our results implications for prospective entomological research and vector management under changing environments.

  17. Thiosemicarbazones as Aedes aegypti larvicidal.

    PubMed

    da Silva, João Bosco P; Navarro, Daniela Maria do A F; da Silva, Aluizio G; Santos, Geanne K N; Dutra, Kamilla A; Moreira, Diogo Rodrigo; Ramos, Mozart N; Espíndola, José Wanderlan P; de Oliveira, Ana Daura T; Brondani, Dalci José; Leite, Ana Cristina L; Hernandes, Marcelo Zaldini; Pereira, Valéria R A; da Rocha, Lucas F; de Castro, Maria Carolina A B; de Oliveira, Beatriz C; Lan, Que; Merz, Kenneth M

    2015-07-15

    A set of aryl- and phenoxymethyl-(thio)semicarbazones were synthetized, characterized and biologically evaluated against the larvae of Aedes aegypti (A. aegypti), the vector responsible for diseases like Dengue and Yellow Fever. (Q)SAR studies were useful for predicting the activities of the compounds not included to create the QSAR model as well as to predict the features of a new compound with improved activity. Docking studies corroborated experimental evidence of AeSCP-2 as a potential target able to explain the larvicidal properties of its compounds. The trend observed between the in silico Docking scores and the in vitro pLC50 (equals -log LC50, at molar concentration) data indicated that the highest larvicidal compounds, or the compounds with the highest values for pLC50, are usually those with the higher docking scores (i.e., greater in silico affinity for the AeSCP-2 target). Determination of cytotoxicity for these compounds in mammal cells demonstrated that the top larvicide compounds are non-toxic.

  18. Thiosemicarbazones as Aedes aegypti larvicidal.

    PubMed

    da Silva, João Bosco P; Navarro, Daniela Maria do A F; da Silva, Aluizio G; Santos, Geanne K N; Dutra, Kamilla A; Moreira, Diogo Rodrigo; Ramos, Mozart N; Espíndola, José Wanderlan P; de Oliveira, Ana Daura T; Brondani, Dalci José; Leite, Ana Cristina L; Hernandes, Marcelo Zaldini; Pereira, Valéria R A; da Rocha, Lucas F; de Castro, Maria Carolina A B; de Oliveira, Beatriz C; Lan, Que; Merz, Kenneth M

    2015-07-15

    A set of aryl- and phenoxymethyl-(thio)semicarbazones were synthetized, characterized and biologically evaluated against the larvae of Aedes aegypti (A. aegypti), the vector responsible for diseases like Dengue and Yellow Fever. (Q)SAR studies were useful for predicting the activities of the compounds not included to create the QSAR model as well as to predict the features of a new compound with improved activity. Docking studies corroborated experimental evidence of AeSCP-2 as a potential target able to explain the larvicidal properties of its compounds. The trend observed between the in silico Docking scores and the in vitro pLC50 (equals -log LC50, at molar concentration) data indicated that the highest larvicidal compounds, or the compounds with the highest values for pLC50, are usually those with the higher docking scores (i.e., greater in silico affinity for the AeSCP-2 target). Determination of cytotoxicity for these compounds in mammal cells demonstrated that the top larvicide compounds are non-toxic. PMID:26087027

  19. A meta-analysis of the factors influencing development rate variation in Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    2014-01-01

    Background Development rates of Aedes aegypti are known to vary with respect to many abiotic and biotic factors including temperature, resource availability, and intraspecific competition. The relative importance of these factors and their interactions are not well established across populations. We performed meta-analysis on a dataset of development rate estimates from 49 studies. Results Meta-analytic results indicated that the environmental factor of temperature is sufficient to explain development rate variability in Ae. aegypti. While diet and density may greatly impact other developmental phenotypes, these results suggest that for development rate these factors should never be considered to the exclusion of temperature. The effect of temperature on development rate is not homogenous or constant. The sources of heterogeneity of the effect of temperature are difficult to analyze due to lack of consistent reporting of larval rearing methods. Conclusions Temperature is the most important ecological determinant of development rate in Ae. aegypti, but its effect is heterogeneous. Ignoring this heterogeneity is problematic for models of vector population and vector-borne disease transmission. PMID:24495345

  20. Cumulative mortality of Aedes aegypti larvae treated with compounds

    PubMed Central

    Torres, Sandra Maria; da Cruz, Nadine Louise Nicolau; Rolim, Vitor Pereira de Matos; Cavalcanti, Maria Inês de Assis; Alves, Leucio Câmara; da Silva, Valdemiro Amaro

    2014-01-01

    OBJECTIVE To evaluate the larvicidal activity of Azadirachta indica, Melaleuca alternifolia, carapa guianensis essential oils and fermented extract of Carica papaya against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). METHODS The larvicide test was performed in triplicate with 300 larvae for each experimental group using the third larval stage, which were exposed for 24h. The groups were: positive control with industrial larvicide (BTI) in concentrations of 0.37 ppm (PC1) and 0.06 ppm (PC2); treated with compounds of essential oils and fermented extract, 50.0% concentration (G1); treated with compounds of essential oils and fermented extract, 25.0% concentration (G2); treated with compounds of essential oils and fermented extract, 12.5% concentration (G3); and negative control group using water (NC1) and using dimethyl (NC2). The larvae were monitored every 60 min using direct visualization. RESULTS No mortality occurred in experimental groups NC1 and NC2 in the 24h exposure period, whereas there was 100% mortality in the PC1 and PC2 groups compared to NC1 and NC2. Mortality rates of 65.0%, 50.0% and 78.0% were observed in the groups G1, G2 and G3 respectively, compared with NC1 and NC2. CONCLUSIONS The association between three essential oils from Azadirachta indica, Melaleuca alternifolia, Carapa guianensis and fermented extract of Carica papaya was efficient at all concentrations. Therefore, it can be used in Aedes aegypti Liverpool third larvae stage control programs. PMID:25119939

  1. Resistance of Aedes aegypti to temephos and adaptive disadvantages

    PubMed Central

    Diniz, Morgana Michele Cavalcanti de Souza Leal; Henriques, Alleksandra Dias da Silva; Leandro, Renata da Silva; Aguiar, Dalvanice Leal; Beserra, Eduardo Barbosa

    2014-01-01

    OBJECTIVE To evaluate the resistance of Aedes aegypti to temephos Fersol 1G (temephos 1% w/w) associated with the adaptive disadvantage of insect populations in the absence of selection pressure. METHODS A diagnostic dose of 0.28 mg a.i./L and doses between 0.28 mg a.i./L and 1.40 mg a.i./L were used. Vector populations collected between 2007 and 2008 in the city of Campina Grande, state of Paraíba, were evaluated. To evaluate competition in the absence of selection pressure, insect populations with initial frequencies of 20.0%, 40.0%, 60.0%, and 80.0% resistant individuals were produced and subjected to the diagnostic dose for two months. Evaluation of the development of aquatic and adult stages allowed comparison of the life cycles in susceptible and resistant populations and construction of fertility life tables. RESULTS No mortality was observed in Ae. aegypti populations subjected to the diagnostic dose of 0.28 mg a.i./L. The decreased mortality observed in populations containing 20.0%, 40.0%, 60.0%, and 80.0% resistant insects indicates that temephos resistance is unstable in the absence of selection pressure. A comparison of the life cycles indicated differences in the duration and viability of the larval phase, but no differences were observed in embryo development, sex ratio, adult longevity, and number of eggs per female. CONCLUSIONS The fertility life table results indicated that some populations had reproductive disadvantages compared with the susceptible population in the absence of selection pressure, indicating the presence of a fitness cost in populations resistant to temephos. PMID:25372168

  2. Cumulative mortality of Aedes aegypti larvae treated with compounds.

    PubMed

    Torres, Sandra Maria; Cruz, Nadine Louise Nicolau da; Rolim, Vitor Pereira de Matos; Cavalcanti, Maria Inês de Assis; Alves, Leucio Câmara; Silva Júnior, Valdemiro Amaro da

    2014-06-01

    OBJECTIVE To evaluate the larvicidal activity of Azadirachta indica, Melaleuca alternifolia, carapa guianensis essential oils and fermented extract of Carica papaya against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). METHODS The larvicide test was performed in triplicate with 300 larvae for each experimental group using the third larval stage, which were exposed for 24h. The groups were: positive control with industrial larvicide (BTI) in concentrations of 0.37 ppm (PC1) and 0.06 ppm (PC2); treated with compounds of essential oils and fermented extract, 50.0% concentration (G1); treated with compounds of essential oils and fermented extract, 25.0% concentration (G2); treated with compounds of essential oils and fermented extract, 12.5% concentration (G3); and negative control group using water (NC1) and using dimethyl (NC2). The larvae were monitored every 60 min using direct visualization. RESULTS No mortality occurred in experimental groups NC1 and NC2 in the 24h exposure period, whereas there was 100% mortality in the PC1 and PC2 groups compared to NC1 and NC2. Mortality rates of 65.0%, 50.0% and 78.0% were observed in the groups G1, G2 and G3 respectively, compared with NC1 and NC2. CONCLUSIONS The association between three essential oils from Azadirachta indica, Melaleuca alternifolia, Carapa guianensis and fermented extract of Carica papaya was efficient at all concentrations. Therefore, it can be used in Aedes aegypti Liverpool third larvae stage control programs. PMID:25119939

  3. Cumulative mortality of Aedes aegypti larvae treated with compounds.

    PubMed

    Torres, Sandra Maria; Cruz, Nadine Louise Nicolau da; Rolim, Vitor Pereira de Matos; Cavalcanti, Maria Inês de Assis; Alves, Leucio Câmara; Silva Júnior, Valdemiro Amaro da

    2014-06-01

    OBJECTIVE To evaluate the larvicidal activity of Azadirachta indica, Melaleuca alternifolia, carapa guianensis essential oils and fermented extract of Carica papaya against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae). METHODS The larvicide test was performed in triplicate with 300 larvae for each experimental group using the third larval stage, which were exposed for 24h. The groups were: positive control with industrial larvicide (BTI) in concentrations of 0.37 ppm (PC1) and 0.06 ppm (PC2); treated with compounds of essential oils and fermented extract, 50.0% concentration (G1); treated with compounds of essential oils and fermented extract, 25.0% concentration (G2); treated with compounds of essential oils and fermented extract, 12.5% concentration (G3); and negative control group using water (NC1) and using dimethyl (NC2). The larvae were monitored every 60 min using direct visualization. RESULTS No mortality occurred in experimental groups NC1 and NC2 in the 24h exposure period, whereas there was 100% mortality in the PC1 and PC2 groups compared to NC1 and NC2. Mortality rates of 65.0%, 50.0% and 78.0% were observed in the groups G1, G2 and G3 respectively, compared with NC1 and NC2. CONCLUSIONS The association between three essential oils from Azadirachta indica, Melaleuca alternifolia, Carapa guianensis and fermented extract of Carica papaya was efficient at all concentrations. Therefore, it can be used in Aedes aegypti Liverpool third larvae stage control programs.

  4. Left-Sided Appendicitis in an Elderly Patient with Midgut Malrotation.

    PubMed

    Chuang, Pei Wen; Huang, Bo-Ming; Liu, Chung Hsien; Chen, Chien-Chin; Tsai, Ming-Jen

    2015-12-01

    Appendicitis is a common surgical abdominal disease with various presentations. Its diagnosis may be obscured by asymptomatic congenital anatomical anomalies like midgut malrotation. Midgut malrotation is a rare fetal anomaly resulting from incomplete or failure of midgut rotation and fixation. It is mostly presented with bowel obstruction or volvulus in early life. Presentation in adult is rare. Here, we report an elderly patient presented with left lower abdominal pain and urinary tract infection. Abdominal computed tomography revealed left-sided appendicitis with non-rotational-type midgut malrotation. Clinicians should bear in mind the possibility of underlying midgut malrotation, as appendicitis could be the first presentation of this rare congenital condition. PMID:27011586

  5. Diminished reproductive fitness associated with the deltamethrin resistance in an Indian strain of dengue vector mosquito, Aedes aegypti L.

    PubMed

    Kumar, Sarita; Thomas, Anita; Samuel, Thomas; Sahgal, Arunima; Verma, Anita; Pillai, M K K

    2009-08-01

    The susceptible (SS) and resistant (DLR) strains of Aedes aegypti selected with deltamethrin and combination of deltamethrin and PBO (1:5) at the larval/adult stage were studied in the laboratory for their reproductive fitness in terms of fecundity, hatchability and longevity of gonotrophic cycles. The DLR strains exhibited 73-88% reduction in the duration of gonotrophic cycles as compared to their SS counterparts. There was a considerable decrease in egg production and hatchability rates in the selected strains of Ae. aegypti, as compared to that of the SS strain. Data indicate deltamethrin being an effective insecticide against Ae. aegypti and a possible correlation between the deltamethrin resistance and disadvantages during reproduction. The most drastic and significant effect was observed in DLR1b strains exhibiting 36.7% decrease in fecundity and 32.4% reduction in hatchability. Another important observation was diminished reproductive fitness in DLR2 strains. This suggests the usefulness of synergized deltamethrin selections in reducing the frequency of resistant individuals. A significant finding was to observe the reproductive disadvantage in adult-selected strains having negligible resistance to deltamethrin implicating the efficacy of deltamethrin as an adulticide rather than as a larvicide. Various probable reasons for the reduction in the reproductive potential and the possible resistance-management strategies of Ae. aegypti are discussed. PMID:19901902

  6. Odonate Nymphs: Generalist Predators and Their Potential in the Management of Dengue Mosquito, Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Akram, Waseem; Ali-Khan, Hafiz Azhar

    2016-01-01

    Background: Dengue is amongst the most serious mosquito-borne infectious disease with hot spots in tropical and subtropical parts of the world. Unfortunately, no licensed vaccine for the disease is currently available in medicine markets. The only option available is the management of dengue vector mosquito, Aedes aegypti (Diptera: Culicidae). Method: Predatory potential of five odonate nymphs namely Anax parthenope, Bradinopyga geminate, Ischnura forcipata, Rhinocypha quadrimaculata, and Orthetrum sabina were evaluated against the 4th instar larvae of the dengue vector mosquito, Aedes aegypti, under laboratory conditions. The consumption of the mosquito larvae was evaluated at three water volume levels viz., 1 liter, 2 liter and 3 liter. Results: The number of Ae. aegypti larvae consumed varied significantly among the five species, and at different levels of water volume (P< 0.01). However, the interaction between odonate nymphs and the water volumes was statistically non-significant (P> 0.05). Ischnura forcipata consumed the highest number of Ae. aegypti larvae (n=56) followed by A. parthenope (n=47) and B. geminate (n=46). The number of larvae consumed was decreased with increasing search area or water volume, and the highest predation was observed at 1-liter water volume. Conclusion: The odonate nymphs could be a good source of biological agents for the management of the mosquitoes at larval stages. PMID:27308283

  7. Midgut microbiota and host immunocompetence underlie Bacillus thuringiensis killing mechanism.

    PubMed

    Caccia, Silvia; Di Lelio, Ilaria; La Storia, Antonietta; Marinelli, Adriana; Varricchio, Paola; Franzetti, Eleonora; Banyuls, Núria; Tettamanti, Gianluca; Casartelli, Morena; Giordana, Barbara; Ferré, Juan; Gigliotti, Silvia; Ercolini, Danilo; Pennacchio, Francesco

    2016-08-23

    Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced nodulation response, which was associated with a significant enhancement of host larvae mortality triggered by B. thuringiensis and a Cry toxin. This was determined by an uncontrolled proliferation of midgut bacteria, after entering the body cavity through toxin-induced epithelial lesions. Consequently, the hemolymphatic microbiota dramatically changed upon treatment with Cry1Ca toxin, showing a remarkable predominance of Serratia and Clostridium species, which switched from asymptomatic gut symbionts to hemocoelic pathogens. These experimental results demonstrate the important contribution of host enteric flora in B. thuringiensis-killing activity and provide a sound foundation for developing new insect control strategies aimed at enhancing the impact of biocontrol agents by reducing the immunocompetence of the host. PMID:27506800

  8. More Frequent than Desired: Midgut Stem Cell Somatic Mutations.

    PubMed

    Li, Qi; Ip, Y Tony

    2015-12-01

    The accumulation of somatic mutations in adult stem cells contributes to the decline of tissue functions and cancer initiation. In this issue of Cell Stem Cell, Siudeja et al. (2015) investigate the rate and mechanism of naturally occurring mutations in Drosophila midgut intestinal stem cells during aging and find high-frequency mutations arising from multiple mechanisms. PMID:26637937

  9. A regulatory network controls nephrocan expression and midgut patterning

    PubMed Central

    Hou, Juan; Wei, Wei; Saund, Ranajeet S.; Xiang, Ping; Cunningham, Thomas J.; Yi, Yuyin; Alder, Olivia; Lu, Daphne Y. D.; Savory, Joanne G. A.; Krentz, Nicole A. J.; Montpetit, Rachel; Cullum, Rebecca; Hofs, Nicole; Lohnes, David; Humphries, R. Keith; Yamanaka, Yojiro; Duester, Gregg; Saijoh, Yukio; Hoodless, Pamela A.

    2014-01-01

    Although many regulatory networks involved in defining definitive endoderm have been identified, the mechanisms through which these networks interact to pattern the endoderm are less well understood. To explore the mechanisms involved in midgut patterning, we dissected the transcriptional regulatory elements of nephrocan (Nepn), the earliest known midgut specific gene in mice. We observed that Nepn expression is dramatically reduced in Sox17−/− and Raldh2−/− embryos compared with wild-type embryos. We further show that Nepn is directly regulated by Sox17 and the retinoic acid (RA) receptor via two enhancer elements located upstream of the gene. Moreover, Nepn expression is modulated by Activin signaling, with high levels inhibiting and low levels enhancing RA-dependent expression. In Foxh1−/− embryos in which Nodal signaling is reduced, the Nepn expression domain is expanded into the anterior gut region, confirming that Nodal signaling can modulate its expression in vivo. Together, Sox17 is required for Nepn expression in the definitive endoderm, while RA signaling restricts expression to the midgut region. A balance of Nodal/Activin signaling regulates the anterior boundary of the midgut expression domain. PMID:25209250

  10. Adult midgut malrotation presented with acute bowel obstruction and ischemia

    PubMed Central

    Zengin, Akile; Uçar, Bercis İmge; Düzgün, Şükrü Aydın; Bayhan, Zülfü; Zeren, Sezgin; Yaylak, Faik; Şanal, Bekir; Bayhan, Nilüfer Araz

    2016-01-01

    Introduction Intestinal malrotation refers to the partial or complete failure of rotation of midgut around the superior mesenteric vessels in embryonic life. Arrested midgut rotation results due to narrow-based mesentery and increases the risk of twisting midgut and subsequent obstruction and necrosis. Presentation of case 40 years old female patient admitted to emergency service with acute abdomen and computerized tomography scan showed dilated large and small intestine segments with air-fluid levels and twisted mesentery around superior mesenteric artery and vein indicating “whirpool sign”. Discussion Malrotation in adults is a rare cause of midgut volvulus as though it should be considered in differential diagnosis in patients presented with acute abdomen and intestinal ischemia. Even though clinical symptoms are obscure, adult patients usually present with vomiting and recurrent abdominal pain due to chronic partial obstruction. Contrast enhanced radiograph has been shown to be the most accurate method. Typical radiological signs are corkscrew sign, which is caused by the dilatation of various duodenal segments at different levels and the relocation of duodenojejunal junction due to jejunum folding. As malrotation commonly causes intestinal obstruction, patients deserve an elective laparotomy. Conclusion Malrotation should be considered in differential diagnosis in patients presented with acute abdomen and intestinal ischemia. Surgical intervention should be prompt to limit morbidity and mortality. PMID:27015011

  11. Vector competence of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) for the DEN2-FJ10 and DEN2-FJ11 strains of the dengue 2 virus in Fujian, China.

    PubMed

    Guo, Xiao-Xia; Li, Chun-Xiao; Zhang, Ying-Mei; Xing, Dan; Dong, Yan-De; Zhang, Heng-Duan; Qin, Cheng-Feng; Zhao, Tong-Yan

    2016-09-01

    Dengue is an acute, emerging, infectious disease transmitted by Aedes mosquitoes that has become a serious global public health problem. The DEN2-FJ10 and DEN2-FJ11 strains of the dengue 2 virus were originally isolated from the serum of a patient with dengue fever in Fujian Province, China, in 1999. Our data provide the first assessment of the vector competence of Aedes mosquitoes with respect to the DEN2-FJ10 and DEN2-FJ11 strains of the dengue virus. There were significant differences in the replication rates of these two viral strains in Aedes albopictus and Aedes aegypti (P<0.05); replication of the DEN2-FJ10 strain was greater in Ae. aegypti than in Ae. albopictus 5 days post infection whereas replication of the DEN2-FJ11 was greater in Ae. albopictus than in Ae. aegypti 7 days post infection. The replicative ability of the DEN2-FJ11 strain was greater than that of the DEN2-FJ10 strain in infected Ae. albopictus. In infected Ae. aegypti, rapid proliferation of the DEN2-FJ10 strain occurred earlier than in the DEN2-FJ11 strain. There were no significant differences in the midgut and salivary gland infection rates of Ae. albopictus and Ae. aegypti with respect to either viral strain. Although the DEN2-FJ10 and DEN2-FJ11 strains differ in their virulence to neonatal rats, there was no significant difference in the ability of either Ae. albopictus or Ae. aegypti to transmit the DEN2-FJ10 and DEN2-FJ10 strains of the dengue 2 virus (P>0.05). In summary, our results indicate that Ae. albopictus and Ae. aegypti mosquitoes are moderately competent vectors of the DEN2-FJ10 and DEN2-FJ11 strains of the dengue virus and provide the first evidence of the effect of these two viral strains on the vector competence of mosquitoes in China.

  12. Vector competence of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) for the DEN2-FJ10 and DEN2-FJ11 strains of the dengue 2 virus in Fujian, China.

    PubMed

    Guo, Xiao-Xia; Li, Chun-Xiao; Zhang, Ying-Mei; Xing, Dan; Dong, Yan-De; Zhang, Heng-Duan; Qin, Cheng-Feng; Zhao, Tong-Yan

    2016-09-01

    Dengue is an acute, emerging, infectious disease transmitted by Aedes mosquitoes that has become a serious global public health problem. The DEN2-FJ10 and DEN2-FJ11 strains of the dengue 2 virus were originally isolated from the serum of a patient with dengue fever in Fujian Province, China, in 1999. Our data provide the first assessment of the vector competence of Aedes mosquitoes with respect to the DEN2-FJ10 and DEN2-FJ11 strains of the dengue virus. There were significant differences in the replication rates of these two viral strains in Aedes albopictus and Aedes aegypti (P<0.05); replication of the DEN2-FJ10 strain was greater in Ae. aegypti than in Ae. albopictus 5 days post infection whereas replication of the DEN2-FJ11 was greater in Ae. albopictus than in Ae. aegypti 7 days post infection. The replicative ability of the DEN2-FJ11 strain was greater than that of the DEN2-FJ10 strain in infected Ae. albopictus. In infected Ae. aegypti, rapid proliferation of the DEN2-FJ10 strain occurred earlier than in the DEN2-FJ11 strain. There were no significant differences in the midgut and salivary gland infection rates of Ae. albopictus and Ae. aegypti with respect to either viral strain. Although the DEN2-FJ10 and DEN2-FJ11 strains differ in their virulence to neonatal rats, there was no significant difference in the ability of either Ae. albopictus or Ae. aegypti to transmit the DEN2-FJ10 and DEN2-FJ10 strains of the dengue 2 virus (P>0.05). In summary, our results indicate that Ae. albopictus and Ae. aegypti mosquitoes are moderately competent vectors of the DEN2-FJ10 and DEN2-FJ11 strains of the dengue virus and provide the first evidence of the effect of these two viral strains on the vector competence of mosquitoes in China. PMID:27260668

  13. Ontogeny and distribution of cholecystokinin-immuno reactive cells in the digestive tract of sharpsnout sea bream, Diplodus puntazzo (Cetti, 1777), during larval development.

    PubMed

    Micale, Valeria; Levanti, Maria Beatrice; Germanà, Antonino; Guerrera, Maria Cristina; Kurokawa, Tadahide; Muglia, Ugo

    2010-10-01

    The appearance and regional distribution of cholecystokinin-immuno reactive cells (CCK-IR) in the developing gut of larval Diplodus puntazzo were studied by means of immunohistochemistry, with the aim of understanding the role of this peptide hormone in the acquisition of digestive capacity. Immunohistochemical reaction showed CCK-IR cells from 10 days after hatching (DAH), near the pyloric sphincter and past the first bend in the midgut, as well as in the hindgut. At 25 DAH CCK-IR cells were scattered throughout the midgut, as well as in the hindgut. Since gastric glands appeared at 30 DAH, CCK-IR cells were most abundant in the anterior midgut, near and including the pyloric caeca, and just afore the ileo-rectal sphincter in the posterior midgut, as well as in the hindgut. In older larvae (39 DAH), CCK-IR cells were mainly distributed in the anterior midgut, including the pyloric caeca, as well as in the hindgut. No CCK-IR cells were detected in the foregut at any stage. The distribution pattern of CCK-IR cells differed from other species which also possess a rotated gut as D. puntazzo. In fact, although cells were abundant in regions where the ingested food is retained, so that they can be stimulated to modulating the release of digestive enzymes, a large number of cells occurred also in the hindgut. PMID:20619264

  14. Hsp70 and small Hsps are the major heat shock protein members involved in midgut metamorphosis in the common cutworm, Spodoptera litura.

    PubMed

    Gu, J; Huang, L-X; Shen, Y; Huang, L-H; Feng, Q-L

    2012-10-01

    Heat shock proteins (Hsps) are important chaperones, which are involved in various signal pathways and regulate lots of physiological processes. Early research suggested that some Hsps are involved in insect development. However, few studies have been carried out to explore the roles of Hsps, especially in larval-pupal metamorphosis. In the present study, 49 Hsp unigenes were identified in the Spodoptera litura transcriptome and their mRNA expression profiles during midgut metamorphosis were examined using a tag-based digital gene expression system. The genes with the most different levels of expression were then cloned and their expression patterns in midguts from sixth instar larvae to pupae were analysed using real time quantitative PCR. The responses of these genes to juvenile hormone (JH) and 20-hydroxyecdysone (20E) were also studied. The results showed that the mRNA levels of 22 Hsp unigenes changed significantly during midgut metamorphosis. Amongst these 22 unigenes, hsp70, hsp20.4 and hsp20.8 were the most up-regulated members, and hsp15.9, hsp19.3 and hsp22.0 were the most down-regulated ones. Further studies showed that hsp70, hsp20.4 and hsp20.8 were remarkably up-regulated by JH. In addition, 20E slightly increased the mRNA levels of both hsp20.4 and hsp20.8. However, hsp15.9, hsp19.3 and hsp22.0 did not respond to either JH or 20E. These results indicate that Hsp70 and small Hsps (sHsps) are probably the major players in midgut metamorphosis in S. litura. The current findings provide valuable insights into the roles of the Hsp superfamily in insect metamorphosis.

  15. Side Effects of Neem Oil on the Midgut Endocrine Cells of the Green Lacewing Ceraeochrysa claveri (Navás) (Neuroptera: Chrysopidae).

    PubMed

    Scudeler, E L; Santos, D C

    2014-04-01

    We described the ultrastructure of Ceraeochrysa claveri (Navás) midgut endocrine cells in larva, pupa, and adult, and evaluated the side effects of ingested neem oil, a botanical insecticide obtained from the seeds of the neem tree (Azadirachta indica), on these cells. During the larval period, C. claveri were fed (ad libitum) Diatraea saccharalis (F.) eggs treated with neem oil at concentrations of 0.5%, 1%, or 2%. Transmission electron microscopy showed that two subtypes of endocrine cells, namely granular and vesicular, occurred in the midgut epithelium during the three stages of the life cycle. Both cell types did not reach the midgut lumen and were positioned basally in the epithelium. The endocrine cells did not show extensive infoldings of the basal plasma membrane, and there were numerous secretory granules in the basal region of the cytoplasm. In the granular endocrine cells, the granules were completely filled with a dense matrix. In the vesicular endocrine cells, the main secretory products consisted of haloed vesicles. Ultrastructural examination indicated that only the granular endocrine cells exhibited signs of morphologic changes of cell injury present in all life cycle stages after the larvae were chronically exposed to neem oil by ingestion. The major cellular damage consisted of dilatation and vesiculation of the rough endoplasmic reticulum and the development of smooth endoplasmic reticulum and mitochondrial swelling. Our data suggest that cytotoxic effects on midgut endocrine cells can contribute to a generalized disruption of the physiological processes in this organ due to a general alteration of endocrine function. PMID:27193522

  16. Genetic transformation of midgut bacteria from the red imported fire ant (Solenopsis invicta).

    PubMed

    Medina, Freder; Li, Haiwen; Vinson, S Bradleigh; Coates, Craig J

    2009-05-01

    In our previous study we isolated 10 bacterial species from fourth-instar larval midguts of the red imported fire ant, Solenopsis invicta. Here we report the genetic transformation and reintroduction of three species (Kluyvera cryocrescens, Serratia marcescens, and isolate 38) into the fire ant host. All three species were transformed with the plasmid vector, pZeoDsRed. High expression levels of DsRed were observed and the plasmid is maintained in these bacteria at 37 degrees C in the absence of antibiotic selection for at least 9 days of subculturing. The transformed bacteria were successfully reintroduced into fire ant larvae and survived in the fire ant gut for at least 7 days. Upon pupal emergence, 7 days after reintroduction, transformed bacteria can still be isolated, however, most were passed out in the meconium. We further demonstrated that the engineered bacteria could be spread within the colony by feeding this meconium to naive larvae with the aid of worker fire ants.

  17. Midgut Microbial Community of Culex quinquefasciatus Mosquito Populations from India

    PubMed Central

    Chandel, Kshitij; Mendki, Murlidhar J.; Parikh, Rasesh Y.; Kulkarni, Girish; Tikar, Sachin N.; Sukumaran, Devanathan; Prakash, Shri; Parashar, Brahma D.; Shouche, Yogesh S.; Veer, Vijay

    2013-01-01

    The mosquito Culex quinquefasciatus is a ubiquitous species that serves as a major vector for west nile virus and lymphatic filariasis. Ingestion of bloodmeal by females triggers a series of physiological processes in the midgut and also exposes them to infection by these pathogens. The bacteria normally harbored in the midgut are known to influence physiology and can also alter the response to various pathogens. The midgut bacteria in female Cx. quinquefasciatus mosquitoes collected over a large geographical area from India was studied. Examination of 16S ribosomal DNA amplicons from culturable microflora revealed the presence of 83 bacterial species belonging to 31 bacterial genera. All of these species belong to three phyla i.e. Proteobacteria, Firmicutes and Actinobacteria. Phylum Proteobacteria was the most dominant phylum (37 species), followed by Firmicutes (33 species) and Actinobacteria (13 species). Phylum Proteobacteria, was dominated by members of γ-proteobacteria class. The genus Staphylococcus was the largest genus represented by 11 species whereas Enterobacter was the most prevalent genus and recovered from all the field stations except Leh. Highest bacterial prevalence was observed from Bhuj (22 species) followed by Nagrota (18 species), Masimpur (18 species) and Hathigarh (16 species). Whereas, least species were observed from Leh (8 species). It has been observed that individual mosquito harbor extremely diverse gut bacteria and have very small overlap bacterial taxa in their gut. This variation in midgut microbiota may be one of the factors responsible for variation in disease transmission rates or vector competence within mosquito population. The present data strongly encourage further investigations to verify the potential role of the detected bacteria in mosquito for the transmission of lymphatic filariasis and west nile virus. To the best of our knowledge this is the first study on midgut microbiota of wild Cx. quinquefasciatus from over a

  18. Silencing of carbonic anhydrase in an Anopheles gambiae larval cell line, Ag55.

    PubMed

    Smith, Kristin E; Linser, Paul J

    2009-06-17

    RNAi has been used extensively to down-regulate proteins in adult mosquitoes; however, it is not well adapted for use in larvae. Larval mosquitoes can generate a pH as high as 10.5 in the anterior region of their midgut. The mechanisms responsible for the generation and maintenance of this pH are not entirely understood, but members of the carbonic anhydrase (CA) family of enzymes have been implicated. Here we use an An. gambiae larval cell line, Ag55 cells, to demonstrate that application of full-length double-stranded RNA specific to one CA, AgCA9, is sufficient to silence AgCA9 mRNA and down-regulate the corresponding protein. This is a first step towards determining the role(s) of these enzymes in pH regulation.

  19. Insecticide susceptibility of Aedes aegypti and Aedes albopictus in Central Africa

    PubMed Central

    2011-01-01

    Background Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894) are the main vectors of dengue (DENV) and chikungunya (CHIKV) viruses worldwide. As there is still no vaccine or specific treatment for DENV and CHIKV, vector control remains the cornerstone of prevention and outbreak control. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides in several areas through the world. Throughout Central Africa no recent data are available susceptible/resistant status of either vector species since the introduction/arrival of Ae. albopictus in this area. We therefore studied the level of resistance of these two major vectors to insecticides commonly used in Africa for mosquito control. Results Aedes aegypti and Ae. albopictus were sampled in six urban localities of Cameroon (Garoua, Bertoua, Yaoundé, Bafia, Buea) and Gabon (Libreville). Larval bioassays, carried out to determine the lethal concentrations (LC50 and LC95) and resistance ratios (RR50 and RR95) suggested that both vector species were susceptible to Bti (Bacillus thuringiensis var israeliensis) and temephos. Bioassays were also performed on adults using WHO diagnostic test kits to assess phenotypic resistance to deltamethrin, DDT, fenitrothion and propoxur. These experiments showed that one population of Ae. aegypti (Libreville) and two populations of Ae. albopictus (Buea and Yaoundé) were resistant to DDT (mortality 36% to 71%). Resistance to deltamethrin was also suspected in Ae. albopictus from Yaoundé (83% mortality). All other field mosquito populations were susceptible to deltamethrin, DDT, fenitrothion and propoxur. No increase in the knockdown times (Kdt50 and Kdt95) was noted in the Yaoundé resistant population compared to other Ae. albopictus populations, suggesting the possible involvement of metabolic resistance to deltamethrin and DDT. Conclusion In view of the recent increase in dengue and

  20. Bioefficacy of Mentha piperita essential oil against dengue fever mosquito Aedes aegypti L

    PubMed Central

    Kumar, Sarita; Wahab, Naim; Warikoo, Radhika

    2011-01-01

    Objective To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti). Methods The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated. Results The essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm. Conclusions The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control. PMID:23569733

  1. Evaluation of Sumithion L-40 against Aedes aegypti (L.) and Aedes albopictus Skuse.

    PubMed

    Loke, S R; Sing, K W; Teoh, G N; Lee, H L

    2015-03-01

    Space spraying of chemical insecticides is still an important mean of controlling Aedes mosquitoes and dengue transmission. For this purpose, the bioefficacy of space-sprayed chemical insecticide should be evaluated from time to time. A simulation field trial was conducted outdoor in an open field and indoor in unoccupied flat units in Kuala Lumpur, to evaluate the adulticidal and larvicidal effects of Sumithion L-40, a ULV formulation of fenitrothion. A thermal fogger with a discharge rate of 240 ml/min was used to disperse Sumithion L-40 at 3 different dosages (350 ml/ha, 500 ml/ha, 750 ml/ha) against lab-bred larvae and adult female Aedes aegypti and Aedes albopictus. An average of more than 80% adult mortality was achieved for outdoor space spray, and 100% adult mortality for indoor space spray, in all tested dosages. Outdoor larvicidal effect was noted up to 14 days and 7 days at a dosage of 500 and 750 ml/ha for Ae. aegypti and Ae. albopictus, respectively. Indoor larvicidal effect was up to 21 days (500 ml/ha) and 14 days (750 ml/ha), respectively, after spraying with larval mortality > 50% against Ae. aegypti. This study concluded that the effective dosage of Sumithion L-40 thermally applied against adult Ae. aegypti and Ae. albopictus indoor and outdoor is 500 and 750 ml/ha. Based on these dosages, effective indoor spray volume is 0.4 - 0.6 ml/m³. Additional indoor and outdoor larvicidal effect will be observed at these application dosages, in addition to adult mortality.

  2. Characterization of Bacillus thuringiensis isolates with potential for control of Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae).

    PubMed

    Santos, F P; Lopes, J; Vilas-Bôas, G T; Zequi, J A C

    2012-04-01

    Aedes aegypti (Linnaeus) is the vector of dengue virus in Brazil. Bioinsecticides based on Bacillus thuringiensis have shown satisfactory results in the control of Diptera, due to the production of proteins called Cry and Cyt. The aim of the present study was to select B. thuringiensis isolates carrying the cry and cyt genes, which are efficient in the control of Ae. aegypti. A collection of 27 isolates of B. thuringiensis, derived from various regions in Brazil, was evaluated using selective bioassays against A. aegypti larvae. Of the 27 isolates, five showed 100% larval mortality at a concentration of 0.05 ppm and the toxicity of these isolates in quantitative bioassays did not differ significantly at temperatures of 15, 25 and 35 °C. In addition, these isolates showed statistical differences for the LC50 values only above pH 9, which indicates a maintenance in insecticide potential in a wide range of alkaline pH values. This result is promising, considering that waste treatment reservoirs generally show an acid pH and higher temperatures. These isolates were also evaluated by PCR using specific primers for the genes cry4A, cry4B, cry10A, cry11, cyt1 and cyt2. The analyses demonstrated that all the five isolates showed amplification products for all the studied genes showing four different Cry proteins, besides Cyt proteins. The obtained results of bioassays and PCR demonstrates the great potential for the use of these isolates in controlling populations of Ae. Aegypti and perhaps other species of mosquitoes in a wide range of environments.

  3. The importance of oxidases in the tolerance of deciduous leaf infusions by Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus (Diptera: Culicidae).

    PubMed

    Lampman, Richard L; Kim, Chang-Hyun; Muturi, Ephantus J

    2014-01-01

    Aedes (Stegomyia) aegypti (L.) and Aedes (Stegomyia) albopictus (Skuse) larvae rely on oxidases to reduce toxicity of water soluble toxins from some senescent tree leaf infusions. The mortality of third instar Ae. aegypti larvae in live oak and pin oak leaf infusions increased significantly in the presence of piperonyl butoxide (PBO), a broad inhibitor of cytochrome P450s (CYPs). In contrast, PBO treatment did not increase mortality in water controls or infusions of northern red oak or sugar maple leaf infusions for Ae. aegypti larvae. A similar pattern was observed for Ae. albopictus larvae, that is, an increase in mortality when CYPs were inhibited in live oak leaf infusions and no increase in sugar maple leaf infusions or water controls. However, the fresh live oak leaf infusion (5 d old) was the most toxic infusion to Ae. aegypti, but appeared less toxic to Ae. albopictus than the older infusions. A direct comparison of survival between the two Aedes species revealed Ae. aegypti exhibited a greater mortality than Ae. albopictus in PBO-treated live oak leaf infusions. These findings suggest that toxic components of some leaf litter in larval habitats may impose cryptic energy costs (detoxification). PMID:24605455

  4. Transcription factor broad suppresses precocious development of adult structures during larval-pupal metamorphosis in the red flour beetle, Tribolium castaneum.

    PubMed

    Parthasarathy, R; Tan, A; Bai, H; Palli, Subba R

    2008-01-01

    Broad (br), a transcription factor containing the Broad-Tramtrack-Bric-a-brac (BTB) and zinc finger domains was shown to mediate 20-hydroxyecdysone (20E) action and pupal development in Drosophila melanogaster and Manduca sexta. We determined the key roles of br during larval-pupal metamorphosis using RNA interference (RNAi) in a coleopteran insect, Tribolium castaneum. Two major peaks of T. castaneum broad (Tcbr) mRNA, one peak at the end of feeding stage prior to the larvae entering the quiescent stage and another peak during the quiescent stage were detected in the whole body and midgut tissue dissected from staged insects. Expression of br during the final instar larval stage is essential for successful larval-pupal metamorphosis, because, RNAi-mediated knock-down of Tcbr during this stage derailed larval-pupal metamorphosis and produced insects that showed larval, pupal and adult structures. Tcbr dsRNA injected into the final instar larvae caused reduction in the mRNA levels of genes known to be involved in 20E action (EcRA, E74 and E75B). Tcbr dsRNA injected into the final instar larvae also caused an increase in the mRNA levels of JH-response genes (JHE and Kr-h1b). Knock-down of Tcbr expression also affected 20E-mediated remodeling of midgut during larval-pupal metamorphosis. These data suggest that the expression of Tcbr during the final instar larval stage promotes pupal program while suppressing the larval and adult programs ensuring a transitory pupal stage in holometabolous insects. PMID:18083350

  5. Effect of temperature on life history traits during immature development of Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) from Córdoba city, Argentina.

    PubMed

    Grech, Marta G; Sartor, Paolo D; Almirón, Walter R; Ludueña-Almeida, Francisco F

    2015-06-01

    We investigated how ambient temperature under fluctuating conditions affects the larval-pupal immature traits of Aedes aegypti and Culex quinquefasciatus mosquitoes from Córdoba city, Argentina, and established each species development threshold and physiological time. Based on life tables, three cohorts of each mosquito species were reared in the laboratory under small fluctuating temperatures conditions of 15.2±1.7°C, 17.9±1.6°C, 21.6±0.7°C and 25.3±0.4°C for Ae. aegypti, and 16.6±1.7°C, 18.7±1.7°C and 25.2±0.3°C for Cx. quinquefasciatus. Immature development time and survival values, and also thermal development threshold and physiological time were estimated. Development times of all larval and pupal stages of Ae. aegypti and Cx. quinquefasciatus were significantly affected by the rearing temperatures, decreasing when temperature increased. Mean Ae. aegypti total (larva+pupa) development time ranged from 21.9 to 8.6 days, at 15.2 and 25.3°C, whereas, for Cx. quinquefasciatus varied between 23.5 to 9.2 days at 16.6 and 25.2°C, respectively. Larval and pupal survival of both species was affected by different rearing temperatures, increasing in general as temperature increased. For Ae. aegypti the total immature survival ranged from 26% at 15.2°C to 92% at 21.6°C; however, temperature did not have significant effect on this variable. The total immature survival of Cx. quinquefasciatus was significantly and positively affected by temperatures, ranging from 32 to 88%, at 16.6 and 25.2°C. The temperature development threshold and the physiological time estimated for Ae. aegypti and Cx. quinquefasciatus were 11.11°C and 93.74 degree-days, and 10.96°C and 136.87 degree-days, respectively. The results of the present study showed that temperature significantly affects the larval-pupal immature traits of these mosquito species of sanitary importance, from the central region of Argentina. All the parameters recorded are useful for the development of

  6. Disruption of Aedes aegypti Olfactory System Development through Chitosan/siRNA Nanoparticle Targeting of semaphorin-1a

    PubMed Central

    Mysore, Keshava; Flannery, Ellen M.; Tomchaney, Michael; Severson, David W.; Duman-Scheel, Molly

    2013-01-01

    Despite the devastating impact of mosquito-borne illnesses on human health, surprisingly little is known about mosquito developmental biology, including development of the olfactory system, a tissue of vector importance. Analysis of mosquito olfactory developmental genetics has been hindered by a lack of means to target specific genes during the development of this sensory system. In this investigation, chitosan/siRNA nanoparticles were used to target semaphorin-1a (sema1a) during olfactory system development in the dengue and yellow fever vector mosquito Aedes aegypti. Immunohistochemical analyses and anterograde tracing of antennal sensory neurons, which were used to track the progression of olfactory development in this species, revealed antennal lobe defects in sema1a knockdown fourth instar larvae. These findings, which correlated with a larval odorant tracking behavioral phenotype, identified previously unreported roles for Sema1a in the developing insect larval olfactory system. Analysis of sema1a knockdown pupae also revealed a number of olfactory phenotypes, including olfactory receptor neuron targeting and projection neuron defects coincident with a collapse in the structure and shape of the antennal lobe and individual glomeruli. This study, which is to our knowledge the first functional genetic analysis of insect olfactory development outside of D. melanogaster, identified critical roles for Sema1a during Ae. aegypti larval and pupal olfactory development and advocates the use of chitosan/siRNA nanoparticles as an effective means of targeting genes during post-embryonic Ae. aegypti development. Use of siRNA nanoparticle methodology to understand sensory developmental genetics in mosquitoes will provide insight into the evolutionary conservation and divergence of key developmental genes which could be exploited in the development of both common and species-specific means for intervention. PMID:23696908

  7. Disruption of Aedes aegypti olfactory system development through chitosan/siRNA nanoparticle targeting of semaphorin-1a.

    PubMed

    Mysore, Keshava; Flannery, Ellen M; Tomchaney, Michael; Severson, David W; Duman-Scheel, Molly

    2013-01-01

    Despite the devastating impact of mosquito-borne illnesses on human health, surprisingly little is known about mosquito developmental biology, including development of the olfactory system, a tissue of vector importance. Analysis of mosquito olfactory developmental genetics has been hindered by a lack of means to target specific genes during the development of this sensory system. In this investigation, chitosan/siRNA nanoparticles were used to target semaphorin-1a (sema1a) during olfactory system development in the dengue and yellow fever vector mosquito Aedes aegypti. Immunohistochemical analyses and anterograde tracing of antennal sensory neurons, which were used to track the progression of olfactory development in this species, revealed antennal lobe defects in sema1a knockdown fourth instar larvae. These findings, which correlated with a larval odorant tracking behavioral phenotype, identified previously unreported roles for Sema1a in the developing insect larval olfactory system. Analysis of sema1a knockdown pupae also revealed a number of olfactory phenotypes, including olfactory receptor neuron targeting and projection neuron defects coincident with a collapse in the structure and shape of the antennal lobe and individual glomeruli. This study, which is to our knowledge the first functional genetic analysis of insect olfactory development outside of D. melanogaster, identified critical roles for Sema1a during Ae. aegypti larval and pupal olfactory development and advocates the use of chitosan/siRNA nanoparticles as an effective means of targeting genes during post-embryonic Ae. aegypti development. Use of siRNA nanoparticle methodology to understand sensory developmental genetics in mosquitoes will provide insight into the evolutionary conservation and divergence of key developmental genes which could be exploited in the development of both common and species-specific means for intervention.

  8. A larval Devonian lungfish.

    PubMed

    Thomson, Keith S; Sutton, Mark; Thomas, Bethia

    2003-12-18

    Perhaps the most enduring of puzzles in palaeontology has been the identity of Palaeospondylus gunni Traquair, a tiny (5-60-mm) vertebrate fossil from the Middle Devonian period (approximately 385 Myr ago) of Scotland, first discovered in 1890 (refs 1-3). It is known principally from a single site (Achanarras Quarry, Caithness) where, paradoxically, it is extremely abundant, preserved in varved lacustrine deposits along with 13 other genera of fishes. Here we show that Palaeospondylus is the larval stage of a lungfish, most probably Dipterus valenciennesi Sedgwick and Murchison 1828 (ref. 5), and that development of the adult form requires a distinct metamorphosis. Palaeospondylus is the oldest known true larva of a vertebrate.

  9. Superior mesenteric vein rotation: a CT sign of midgut malrotation

    SciTech Connect

    Nichols, D.M.; Li, D.K.

    1983-10-01

    Computed tomography (CT) of the pancreas, with its excellent display of peripancreatic anatomy, allows visualization of the major vessels entering the mesenteric root. In scans of the normal upper abdomen obtained at or just below the level of the uncinate process of the pancreas, the proximal superior mesenteric vein (SMV) easily can be identified lying on the right ventral aspect of the superior mesenteric artery (SMA). The authors have observed a characteristic abnormality in this normal vascular arrangement on CT scans of the pancreas in three adult patients with suspected chronic pancreatitis who were subsequently proved to have midgut malrotation. They called this the SMV rotation sign and believe that its detection even on CT scans limited to the level of the pancreas should alert the radiologist to the presence of a midgut malrotation that may have been unsuspected.

  10. Investigating the Potential Range Expansion of the Vector Mosquito Aedes Aegypti in Mexico with NASA Earth Science Remote Sensing Results

    NASA Technical Reports Server (NTRS)

    Crosson, W. L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Monaghan, A. J.; Eisen, L.; Lozano-Fuentes, S.; Ochoa, C.; Tapia, B.; Welsh-Rodriquez, C. M.; Quattrochi, D.; MorenoMadrinan, M. J.

    2012-01-01

    In tropical and sub ]tropical regions, the mosquito Aedes aegypti is the major vector for the virus causing dengue, a serious public health issue in these areas. Through ongoing NSF- and NASA-funded studies, field surveys of Aedes aegypti and an integrated modeling approach are being used to improve our understanding of the potential range of the mosquito to expand toward heavily populated high elevation areas such as Mexico City under various climate change and socio ]economic scenarios. This work serves three primary objectives: (1) Employ NASA remotely-sensed data to supplement the environmental monitoring and modeling component of the project. These data-- for example, surface temperature, precipitation, vegetation indices, soil moisture and elevation-- are critical for understanding the habitat necessary for mosquito survival and abundance; (2) Implement training sessions to instruct scientists and students from Mexico and the U.S. on how to use remote sensing and implement the NASA SERVIR Regional Visualization and Monitoring System; (3) Employ the SERVIR framework to optimize the dissemination of key project results in order to increase their societal relevance and benefits in developing climate adaptation strategies. Field surveys of larval, pupal and adult Aedes aegypti, as well as detailed physical and social household characteristics, were conducted in the summers of 2011and 2012 at geographic scales from the household to the community along a transect from sea level to 2400 m ASL. These data are being used in models to estimate Aedes aegypti habitat suitability. In 2011, Aedes aegypti were identified at an elevation of over 2150 m in Puebla, the highest elevation at which this species has been observed.

  11. Investigating the Potential Range Expansion of the Vector Mosquito Aedes aegypti in Mexico with NASA Earth Science Remote Sensing Results

    NASA Astrophysics Data System (ADS)

    Crosson, W. L.; Eisen, L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Lozano-Fuentes, S.; Monaghan, A. J.; Moreno Madriñán, M. J.; Ochoa, C.; Quattrochi, D.; Tapia, B.; Welsh-Rodriguez, C. M.

    2012-12-01

    In tropical and sub-tropical regions, the mosquito Aedes aegypti is the major vector for the virus causing dengue, a serious public health issue in these areas. Through ongoing NSF- and NASA-funded studies, field surveys of Aedes aegypti and an integrated modeling approach are being used to improve our understanding of the potential range of the mosquito to expand toward heavily populated high elevation areas such as Mexico City under various climate change and socio-economic scenarios. This work serves three primary objectives: (1) Employ NASA remotely-sensed data to supplement the environmental monitoring and modeling component of the project. These data -- for example, surface temperature, precipitation, vegetation indices, soil moisture and elevation -- are critical for understanding the habitat necessary for mosquito survival and abundance; (2) Implement training sessions to instruct scientists and students from Mexico and the U.S. on how to use remote sensing and implement the NASA SERVIR Regional Visualization and Monitoring System; (3) Employ the SERVIR framework to optimize the dissemination of key project results in order to increase their societal relevance and benefits in developing climate adaptation strategies. Field surveys of larval, pupal and adult Aedes aegypti, as well as detailed physical and social household characteristics, were conducted in the summers of 2011and 2012 at geographic scales from the household to the community along a transect from sea level to 2400 m ASL. These data are being used in models to estimate Aedes aegypti habitat suitability. In 2011, Aedes aegypti were identified at an elevation of over 2150 m in Puebla, the highest elevation at which this species has been observed.

  12. The lethal effects of Cyperus iria on Aedes aegypti.

    PubMed

    Schwartz, A M; Paskewitz, S M; Orth, A P; Tesch, M J; Toong, Y C; Goodman, W G

    1998-03-01

    The sedge Cyperus iria, a common weed in rice, contains large amounts of the insect hormone (10R) juvenile hormone III (JH III). Given its widespread distribution in Asia and Africa, we examined the possibility that C. iria could be used as a safe, inexpensive, and readily available mosquito larvicide. Plants of varying ages were harvested and leaves tested for lethal effects on larvae of the yellow fever mosquito, Aedes aegypti. The median lethal doses (LD50s) for frozen leaves from 1- and 2-month-old plants were 267 and 427 mg/100 ml of water, respectively. Leaves from 1-month-old C. iria contained 193 micrograms JH III/g fresh weight, whereas leaves from 2-month-old plants contained 143 micrograms JH III/g fresh weight. Larval sensitivity to the plant differed with age; 4-day-old larvae displayed the greatest mortality followed in decreasing sensitivity by larvae 5, 6, 3, and 2 days old. Six Cyperus species (C. albostriatus, C. alternifolius, C. esculentus, C. iria, C. miliifolius, and C. papyrus) of similar developmental stage were assayed for JH III content. Only C. iria was found to contain significant levels of JH III. PMID:9599328

  13. The effect of silencing arginine kinase by RNAi on the larval development of Helicoverpa armigera.

    PubMed

    Qi, X-L; Su, X-F; Lu, G-Q; Liu, C-X; Liang, G-M; Cheng, H-M

    2015-10-01

    Arginine kinase (AK) is an important regulation factor of energy metabolism in invertebrate. An arginine kinase gene, named HaAK, was identified to be differentially expressed between Cry1Ac-susceptible (96S) and Cry1Ac-resistant (Bt-R) Helicoverpa armigera larvae using cDNA-amplification fragment length polymorphism analysis. The full-length open reading frame sequence of HaAK gene with 1068 bp was isolated from H. armigera. Quantitative reverse transcription polymerase chain reaction assay revealed that HaAK gene is specifically expressed in multiple tissues and at larval developmental stages. The peak expression level of HaAK was detected in the midgut of the fifth-instar larvae. Moreover, the expression of HaAK was obviously down-regulated in Bt-R larvae. We further constructed a dsRNA vector directly targeting HaAK and employed RNAi technology to control the larvae. The feeding bioassays showed that minute quantities of dsRNA could greatly increase the larval mortality and delay the larval pupation. Silencing of HaAK significantly retarded the larval development, indicating that HaAK is a potential target for RNA interference-based pest management. PMID:26138927

  14. Risk of dengue occurrence based on the capture of gravid Aedes aegypti females using MosquiTRAP.

    PubMed

    Steffler, Lizandra Makowski; Marteis, Letícia Silva; Dolabella, Silvio Santana; Cavalcanti, Sócrates Cabral de Holanda; Santos, Roseli La Corte Dos

    2011-05-01

    We assessed the risk classification of dengue fever based on the capture of Aedes aegypti adults using MosquiTRAP, a type of sticky trap, in comparison with traditional larval infestation indices. A total of 27 MosquiTRAPs were installed, with one trap per block, and were inspected weekly between November 2008-February 2009. Infestation baseline data were obtained from a survey conducted prior to trap installation. The index generated by MosquiTRAP and house index (HI) classified the area "in alert situation". The set for risk of dengue occurrence proposed by the use of MosquiTRAP classify areas in the same way of the traditional HI.

  15. Intestinal stem cells in the adult Drosophila midgut

    SciTech Connect

    Jiang, Huaqi; Edgar, Bruce A.

    2011-11-15

    Drosophila has long been an excellent model organism for studying stem cell biology. Notably, studies of Drosophila's germline stem cells have been instrumental in developing the stem cell niche concept. The recent discovery of somatic stem cells in adult Drosophila, particularly the intestinal stem cells (ISCs) of the midgut, has established Drosophila as an exciting model to study stem cell-mediated adult tissue homeostasis and regeneration. Here, we review the major signaling pathways that regulate the self-renewal, proliferation and differentiation of Drosophila ISCs, discussing how this regulation maintains midgut homeostasis and mediates regeneration of the intestinal epithelium after injury. -- Highlights: Black-Right-Pointing-Pointer The homeostasis and regeneration of adult fly midguts are mediated by ISCs. Black-Right-Pointing-Pointer Damaged enterocytes induce the proliferation of intestinal stem cells (ISC). Black-Right-Pointing-Pointer EGFR and Jak/Stat signalings mediate compensatory ISC proliferation. Black-Right-Pointing-Pointer Notch signaling regulates ISC self-renewal and differentiation.

  16. Identification and characterization of Aedes aegypti aminopeptidase N as a putative receptor of Bacillus thuringiensis Cry11A toxin

    PubMed Central

    Chen, Jianwu; Aimanova, Karlygash G.; Pan, Songqin; Gill, Sarjeet S.

    2009-01-01

    Bacillus thuringiensis subsp. israelensis, which is used worldwide to control Aedes aegypti larvae, produces Cry11Aa and other toxins during sporulation. In this study, pull-down assays were performed using biotinylated Cry11Aa toxin and solubilized brush border membrane vesicles prepared from midguts of Aedes larvae. Three of the eluted proteins were identified as aminopeptidease N (APN), one of which was a 140 kDa protein, named AaeAPN1 (AAEL 012778 in VectorBase). This protein localizes to the apical side of posterior midgut epithelial cells of larva. The full-length AaeAPN1 was cloned and expressed in E. coli and in Sf21 cells. AaeAPN1 protein expressed in Sf21 cells was enzymatically active, had a GPI-anchor but did not bind Cry11Aa. A truncated AaeAPN1, however, binds Cry11Aa with high affinity, and also Cry11Ba but with lower affinity. BBMV but not Sf21 expressed AaeAPN1 can be detected by wheat germ agglutinin suggesting the native but Sf21 cell expressed APN1 contains N-acetylglucosamine moieties. PMID:19698787

  17. Spatial Stability of Adult Aedes aegypti Populations

    PubMed Central

    Barrera, Roberto

    2011-01-01

    Vector control programs could be more efficient by identifying the location of highly productive sites of Aedes aegypti. This study explored if the number of female adults of Ae. aegypti in BG-Sentinel traps was clustered and if their spatial distribution changed in time in two neighborhoods in San Juan, Puerto Rico. Traps were uniformly distributed across each neighborhood (130 m from each other), and samples were taken every 3 weeks. Global and local spatial autocorrelations were explored. Spatial stability existed if the rank order of trap captures was kept in time. There was lack of global autocorrelation in both neighborhoods, precluding their stratification for control purposes. Hot and cold spots were identified, revealing the highly focal nature of Ae. aegypti. There was significant spatial stability throughout the study in both locations. The consistency in trap productivity in time could be used to increase the effectiveness of vector and dengue control programs. PMID:22144449

  18. Cellulolytic environment in the midgut of the wood-feeding higher termite Nasutitermes takasagoensis.

    PubMed

    Tokuda, Gaku; Watanabe, Hirofumi; Hojo, Masaru; Fujita, Ai; Makiya, Hiromi; Miyagi, Mio; Arakawa, Gaku; Arioka, Manabu

    2012-01-01

    Unlike lower termites, xylophagous higher termites thrive on wood without the aid of symbiotic protists. In the higher termite Nasutitermes takasagoensis, both endogenous endo-β-1,4-glucanase and β-glucosidase genes are expressed in the midgut, which is believed to be the main site of cellulose digestion. To further explore the detailed cellulolytic system in the midgut of N. takasagoensis, we performed immunohistochemistry and digital light microscopy to determine distributions of cellulolytic enzymes in the salivary glands and the midgut as well as the total cellulolytic activity in the midgut. Although cellulolytic enzymes were uniformly produced in the midgut epithelium, the concentration of endo-β-1,4-glucanase activity and luminal volume in the midgut were comparable to those of the wood-feeding lower termite Coptotermes formosanus, which digests cellulose with the aid of hindgut protists. However, the size of ingested wood particles was considerably larger in N. takasagoensis than that in C. formosanus. Nevertheless, it is possible that the cellulolytic system in the midgut of N. takasagoensis hydrolyzes highly crystalline cellulose to a certain extent. The glucose produced did not accumulate in the midgut lumen. Therefore, the present study suggests that the midgut of the higher termite provides the necessary conditions for cellulolysis.

  19. The impact of temperature on the bionomics of Aedes (Stegomyia) aegypti, with special reference to the cool geographic range margins.

    PubMed

    Eisen, Lars; Monaghan, Andrew J; Lozano-Fuentes, Saul; Steinhoff, Daniel F; Hayden, Mary H; Bieringer, Paul E

    2014-05-01

    developmental zero temperature (10-14 degrees C) is exceeded, there is a near-linear relationship up to 30 degrees C. Above this temperature, the development rate is relatively stable or even decreases slightly before falling dramatically near the upper developmental zero temperature, which occurs at -38-42 degrees C. Based on life stage-specific linear relationships between water temperature and development rate in the 15-28 degrees C range, the lower developmental zero temperature is estimated to be 14.0 degrees C for eggs, 11.8 degrees C for larvae, and 10.3 degrees C for pupae. We further conclude that available population dynamics models for Ae. aegypti, such as CIMSiM and Skeeter Buster, likely produce robust predictions based on water temperatures in the 16-35 degrees C range, which includes the geographic areas where Ae. aegypti and its associated pathogens present the greatest threat to human health, but that they may be less reliable in cool range margins where water temperatures regularly fall below 15 degrees C. Finally, we identify knowledge or data gaps that hinder our ability to predict risk of human exposure to Ae. aegypti at the cool margins of its range, now and in the future, based on impacts on mosquito population dynamics of temperature and other important factors, such as water nutrient content, larval density, presence of biological competitors, and human behavior. PMID:24897844

  20. The impact of temperature on the bionomics of Aedes (Stegomyia) aegypti, with special reference to the cool geographic range margins.

    PubMed

    Eisen, Lars; Monaghan, Andrew J; Lozano-Fuentes, Saul; Steinhoff, Daniel F; Hayden, Mary H; Bieringer, Paul E

    2014-05-01

    developmental zero temperature (10-14 degrees C) is exceeded, there is a near-linear relationship up to 30 degrees C. Above this temperature, the development rate is relatively stable or even decreases slightly before falling dramatically near the upper developmental zero temperature, which occurs at -38-42 degrees C. Based on life stage-specific linear relationships between water temperature and development rate in the 15-28 degrees C range, the lower developmental zero temperature is estimated to be 14.0 degrees C for eggs, 11.8 degrees C for larvae, and 10.3 degrees C for pupae. We further conclude that available population dynamics models for Ae. aegypti, such as CIMSiM and Skeeter Buster, likely produce robust predictions based on water temperatures in the 16-35 degrees C range, which includes the geographic areas where Ae. aegypti and its associated pathogens present the greatest threat to human health, but that they may be less reliable in cool range margins where water temperatures regularly fall below 15 degrees C. Finally, we identify knowledge or data gaps that hinder our ability to predict risk of human exposure to Ae. aegypti at the cool margins of its range, now and in the future, based on impacts on mosquito population dynamics of temperature and other important factors, such as water nutrient content, larval density, presence of biological competitors, and human behavior.

  1. Restriction fragment length polymorphism mapping of quantitative trait loci for malaria parasite susceptibility in the mosquito Aedes aegypti

    SciTech Connect

    Severson, D.W.; Thathy, V.; Mori, A.

    1995-04-01

    Susceptibility of the mosquito Aedes aegypti to the malarial parasite Plasmodium gallinaceum was investigated as a quantitative trait using restriction fragment length polymorphisms (RFLP). Two F{sub 2} populations of mosquitoes were independently prepared from pairwise matings between a highly susceptible and a refractory strain of A. aegypti. RFLP were tested for association with oocyst development on the mosquito midgut. Two putative quantitative trait loci (QTL) were identified that significantly affect susceptibility. One QTL, pgs [2,LF98], is located on chromosome 2 and accounted for 65 and 49% of the observed phenotypic variance in the two populations, respectively. A second QTL, pgs[3,MalI], is located on chromosome 3 and accounted for 14 and 10% of the observed phenotypic variance in the two populations, respectively. Both QTL exhibit a partial dominance effect on susceptibility, wherein the dominance effect is derived from the refractory parent. No indication of epistasis between these QTL was detected. Evidence suggests that either a tightly linked cluster of independent genes or a single locus affecting susceptibility to various mosquito-borne parasites and pathogens has evolved near the LF98 locus; in addition to P. gallinaceum susceptibility, this general genome region has previously been implicated in susceptibility to the filaria nematode Brugia malayi and the yellow fever virus. 35 refs., 2 figs., 3 tabs.

  2. A vacuolar-type proton pump in a vesicle fraction enriched with potassium transporting plasma membranes from tobacco hornworm midgut

    SciTech Connect

    Wieczorek, H.; Weerth, S.; Schindlbeck, M.; Klein, U.

    1989-07-05

    Mg-ATP dependent electrogenic proton transport, monitored with fluorescent acridine orange, 9-aminoacridine, and oxonol V, was investigated in a fraction enriched with potassium transporting goblet cell apical membranes of Manduca sexta larval midgut. Proton transport and the ATPase activity from the goblet cell apical membrane exhibited similar substrate specificity and inhibitor sensitivity. ATP and GTP were far better substrates than UTP, CTP, ADP, and AMP. Azide and vanadate did not inhibit proton transport, whereas 100 microM N,N'-dicyclohexylcarbodiimide and 30 microM N-ethylmaleimide were inhibitors. The pH gradient generated by ATP and limiting its hydrolysis was 2-3 pH units. Unlike the ATPase activity, proton transport was not stimulated by KCl. In the presence of 20 mM KCl, a proton gradient could not be developed or was dissipated. Monovalent cations counteracted the proton gradient in an order of efficacy like that for stimulation of the membrane-bound ATPase activity: K+ = Rb+ much greater than Li+ greater than Na+ greater than choline (chloride salts). Like proton transport, the generation of an ATP dependent and azide- and vanadate-insensitive membrane potential (vesicle interior positive) was prevented largely by 100 microM N,N'-dicyclohexylcarbodiimide and 30 microM N-ethylmaleimide. Unlike proton transport, the membrane potential was not affected by 20 mM KCl. In the presence of 150 mM choline chloride, the generation of a membrane potential was suppressed, whereas the pH gradient increased 40%, indicating an anion conductance in the vesicle membrane. Altogether, the results led to the following new hypothesis of electrogenic potassium transport in the lepidopteran midgut. A vacuolar-type electrogenic ATPase pumps protons across the apical membrane of the goblet cell, thus energizing electroneutral proton/potassium antiport. The result is a net active and electrogenic potassium flux.

  3. Spatial and Temporal Variation in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Numbers in the Yogyakarta Area of Java, Indonesia, With Implications for Wolbachia Releases.

    PubMed

    Tantowijoyo, W; Arguni, E; Johnson, P; Budiwati, N; Nurhayati, P I; Fitriana, I; Wardana, S; Ardiansyah, H; Turley, A P; Ryan, P; O'Neill, S L; Hoffmann, A A

    2016-01-01

    of mosquito vector populations, particularly through Wolbachia endosymbionts. The success of these strategies depends on understanding the dynamics of vector populations. In preparation for Wolbachia releases around Yogyakarta, we have studied Aedes populations in five hamlets. Adult monitoring with BioGent- Sentinel (BG-S) traps indicated that hamlet populations had different dynamics across the year; while there was an increase in Aedes aegypti (L.) and Aedes albopictus (Skuse) numbers in the wet season, species abundance remained relatively stable in some hamlets but changed markedly (>2 fold) in others. Local rainfall a month prior to monitoring partly predicted numbers of Ae. aegypti but not Ae. albopictus. Site differences in population size indicated by BG-S traps were also evident in ovitrap data. Egg or larval collections with ovitraps repeated at the same location suggested spatial autocorrelation (<250 m) in the areas of the hamlets where Ae. aegypti numbers were high. Overall, there was a weak negative association (r<0.43) between Ae. aegypti and Ae. albopictus numbers in ovitraps when averaged across collections. Ae. albopictus numbers in ovitraps and BG-S traps were positively correlated with vegetation around areas where traps were placed, while Ae. aegypti were negatively correlated with this feature. These data inform intervention strategies by defining periods when mosquito densities are high, highlighting the importance of local site characteristics on populations, and suggesting relatively weak interactions between Ae. aegypti and Ae. albopictus. They also indicate local areas within hamlets where consistently high mosquito densities may influence Wolbachia invasions and other interventions. PMID:26576934

  4. Spatial and Temporal Variation in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Numbers in the Yogyakarta Area of Java, Indonesia, With Implications for Wolbachia Releases.

    PubMed

    Tantowijoyo, W; Arguni, E; Johnson, P; Budiwati, N; Nurhayati, P I; Fitriana, I; Wardana, S; Ardiansyah, H; Turley, A P; Ryan, P; O'Neill, S L; Hoffmann, A A

    2016-01-01

    of mosquito vector populations, particularly through Wolbachia endosymbionts. The success of these strategies depends on understanding the dynamics of vector populations. In preparation for Wolbachia releases around Yogyakarta, we have studied Aedes populations in five hamlets. Adult monitoring with BioGent- Sentinel (BG-S) traps indicated that hamlet populations had different dynamics across the year; while there was an increase in Aedes aegypti (L.) and Aedes albopictus (Skuse) numbers in the wet season, species abundance remained relatively stable in some hamlets but changed markedly (>2 fold) in others. Local rainfall a month prior to monitoring partly predicted numbers of Ae. aegypti but not Ae. albopictus. Site differences in population size indicated by BG-S traps were also evident in ovitrap data. Egg or larval collections with ovitraps repeated at the same location suggested spatial autocorrelation (<250 m) in the areas of the hamlets where Ae. aegypti numbers were high. Overall, there was a weak negative association (r<0.43) between Ae. aegypti and Ae. albopictus numbers in ovitraps when averaged across collections. Ae. albopictus numbers in ovitraps and BG-S traps were positively correlated with vegetation around areas where traps were placed, while Ae. aegypti were negatively correlated with this feature. These data inform intervention strategies by defining periods when mosquito densities are high, highlighting the importance of local site characteristics on populations, and suggesting relatively weak interactions between Ae. aegypti and Ae. albopictus. They also indicate local areas within hamlets where consistently high mosquito densities may influence Wolbachia invasions and other interventions.

  5. Neuropeptidomics of the mosquito Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neuropeptidomic data were collected on the mosquito Ae. aegypti which is considered the most tractable mosquito species for physiological and endocrine studies. The data were solely obtained by direct mass spectrometric profiling, including tandem fragmentation, of selected tissues from single speci...

  6. The Influence of Diet on the Use of Near-Infrared Spectroscopy to Determine the Age of Female Aedes aegypti Mosquitoes.

    PubMed

    Liebman, Kelly; Swamidoss, Isabel; Vizcaino, Lucrecia; Lenhart, Audrey; Dowell, Floyd; Wirtz, Robert

    2015-05-01

    Interventions targeting adult mosquitoes are used to combat transmission of vector-borne diseases, including dengue. Without available vaccines, targeting the primary vector, Aedes aegypti, is essential to prevent transmission. Older mosquitoes (≥ 7 days) are of greatest epidemiological significance due to the 7-day extrinsic incubation period of the virus. Age-grading of female mosquitoes is necessary to identify post-intervention changes in mosquito population age structure. We developed models using near-infrared spectroscopy (NIRS) to age-grade adult female Ae. aegypti. To determine if diet affects the ability of NIRS models to predict age, two identical larval groups were fed either fish food or infant cereal. Adult females were separated and fed sugar water ± blood, resulting in four experimental groups. Females were killed 1, 4, 7, 10, 13, or 16 days postemergence. The head/thorax of each mosquito was scanned using a near-infrared spectrometer. Scans from each group were analyzed, and multiple models were developed using partial least squares regression. The best model included all experimental groups, and positively predicted the age group (< or ≥ 7 days) of 90.2% mosquitoes. These results suggest both larval and adult diets can affect the ability of NIRS models to accurately assign age categories to female Ae. aegypti.

  7. Exploring new thermal fog and ultra-low volume technologies to improve indoor control of the dengue vector, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Harwood, James F; Farooq, Muhammad; Richardson, Alec G; Doud, Carl W; Putnam, John L; Szumlas, Daniel E; Richardson, Jason H

    2014-07-01

    Control of the mosquito vector, Aedes aegypti (L.), inside human habitations must be performed quickly and efficiently to reduce the risk of transmission during dengue outbreaks. As part of abroad study to assess the efficacy of dengue vector control tools for the U.S. Military, two pesticide delivery systems (ultra-low volume [ULV] and thermal fog) were evaluated for their ability to provide immediate control of Ae. aegypti mosquitoes with a contact insecticide inside simulated urban structures. An insect growth regulator was also applied to determine how well each sprayer delivered lethal doses of active ingredient to indoor water containers for pupal control. Mortality of caged Ae. aegypti, pesticide droplet size, and droplet deposition were recorded after applications. In addition, larval and pupal mortality was measured from treated water samples for 4 wk after the applications. The ULV and the thermal fogger performed equally well in delivering lethal doses of adulticide throughout the structures. The ULV resulted in greater larval mortality and adult emergence inhibition in the water containers for a longer period than the thermal fogger. Therefore, the ULV technology is expected to be a better tool for sustained vector suppression when combined with an effective insect growth regulator. However, during a dengue outbreak, either delivery system should provide an immediate knockdown of vector populations that may lower the risk of infection and allow other suppression strategies to be implemented.

  8. [Biology and thermal exigency of Aedes aegypti (L.) (Diptera: Culicidae) from four bioclimatic localities of Paraíba].

    PubMed

    Beserra, Eduardo B; de Castro, Francisco P; dos Santos, José W; Santos, Tatiana da S; Fernandes, Carlos R M

    2006-01-01

    The present work aimed at estimating the thermal requirements for the development and the number of generations per year of Aedes aegypti (L.) under natural conditions. The life cycle of A. aegypti populations was studied at constant temperatures of 18, 22, 26, 30 and 34 degrees C, and 12 h photophase. The development period, egg viability and larval and pupal survival were evaluated daily as well as adult longevity and fecundity. The low threshold temperature of development (Tb) and the thermal constant (K) were determined. The number of generations per year in laboratory and field were also estimated. The favorable temperature to A. aegypti development is between 21 degrees C and 29 degrees C, and to longevity and fecundity is between 22 degrees C and 30 degrees C. The egg to adult basal temperature, thermal constant and the number of generations in field were, in order, 9.5, 8.5, 3.4, 7.1, 13.5 degrees C; 244.5, 273.9, 298.5, 280.9 and 161.8 degree-days; and 21.9, 23.8, 24.2, 21.1 and 22.1 generations in populations from Boqueirão, Brejo dos Santos, Campina Grande, Itaporanga and Remígio.

  9. Evaluation of the insect growth regulator Lufenuron (Match®) for control of Aedes aegypti by simulated field trials.

    PubMed

    Salokhe, S G; Deshpande, S G; Mukherjee, S N

    2012-09-01

    The insect growth regulator, Lufenuron, at concentrations of even multiples of LC(90) (determined under laboratory conditions) was tested against the III instar larvae of Aedes aegypti under simulated field conditions. For all concentrations tested, 100 % mortality of the larvae was observed within 24 h of exposure to Lufenuron-treated water. In experiments with LC(90) × 4 Lufenuron concentration and where 15 % of water volume was replaced daily, percent mortality of the larvae was reduced to 40 % after the 54th day of treatment. Percentage mortality of the III instar larvae on the 54th day was higher in water with LC(90) × 6 concentration than that observed for water with LC(90) × 4 of Lufenuron. In the experiments with LC(90) × 4 and LC(90) × 6 concentrations of Lufenuron where 15 % of water volume was replaced weekly, larval mortality obtained after the eighth week was 68.75 and 88.33 %, respectively. In LC(90) × 4 and LC(90) × 6 of Lufenuron-treated stagnant water (without replacement of water), the percent mortality of the larvae on the 55th day was 65 and 90 %, respectively. Introducing a fresh batch of III instar A. aegypti larvae in the Lufenuron-treated waters revealed that residual activity of Lufenuron was sustained for 45 days after the treatment. All these experiments revealed that Lufenuron not only affects the prevalence of the A. aegypti larvae but also induces the development of abnormal adults. PMID:22638920

  10. Enteritis necroticans with midgut necrosis caused by Clostridium perfringens.

    PubMed

    Clarke, L E; Diekmann-Guiroy, B; McNamee, W; Java, D J; Weiss, S M

    1994-05-01

    Enteritis necroticans is a necrotizing process manifesting as segmental gangrene of the bowel, triggered by Clostridium perfringens toxins under specific dietary conditions. It is a rare disease in developed countries and is probably underdiagnosed. A case of enteritis necroticans presenting with midgut necrosis with sepsis and hemolysis is reported herein. Bacteriologic culture of blood and peritoneal content revealed C perfringens. Dietary history, including the ingestion of meat together with sweet potatoes, should increase clinical suspicion of enteritis necroticans. Early recognition and timely surgical intervention are required for successful treatment. Clinicians are encouraged to be aware of this clinically fulminant yet rarely recognized surgical entity.

  11. Electroantennogram, flight orientation, and oviposition responses of Aedes aegypti to the oviposition pheromone n-heneicosane.

    PubMed

    Seenivasagan, T; Sharma, Kavita R; Sekhar, K; Ganesan, K; Prakash, Shri; Vijayaraghavan, R

    2009-03-01

    Oviposition pheromones specifically influence the females of many insects to lay eggs in the sites resulting in more egg deposition. A previous report describes the principal role of n-heneicosane (C(21)) identified and characterized from the larval cuticle of Aedes aegypti (L.) in attracting the gravid mosquitoes to oviposit in treated substrates among other chemical components. However, the means by which this compound is perceived by the females for oviposition has not been reported. In this study, we have recorded the peripheral olfactory responses from the antenna of Ae. aegypti from 10(-7) g to 10(-3) g doses of n-heneicosane. The EAG response of female mosquitoes increased in a dose-dependent manner with increasing stimulus strength. In the orientation assay using Y-maze olfactometer, female mosquitoes were attracted to the odor plume of 10(-6) g and 10(-5) g dose, while the higher dose of 10(-3) g plume enforced repellency to gravid mosquitoes. The response to oviposition substrates by gravid Ae. aegypti females differed across the range of concentrations of n-heneicosane under multiple choice conditions, larger number of eggs were deposited in 10 ppm (10 mg/l) solutions compared to lower and higher concentrations indicating 10 ppm was most attractive. Application of n-heneicosane at 10 ppm in breeding habitats will be a useful method to attract the gravid mosquitoes using ovitraps for surveillance and monitoring. The possible use of this compound in monitoring of mosquito population in endemic areas in relevance to integrated vector management strategies is discussed in detail.

  12. Essential oils and their compounds as Aedes aegypti L. (Diptera: Culicidae) larvicides: review.

    PubMed

    Dias, Clarice Noleto; Moraes, Denise Fernandes Coutinho

    2014-02-01

    This review aims to describe essential oils and their constituent compounds that exhibit bioactivity against Aedes aegypti L. (Diptera: Culicidae) larvae, the immature stage of the primary vector of dengue. This review is based on original articles obtained by searching on major databases. Our literature review revealed that 361 essential oils from 269 plant species have been tested for their larvicidal activity. More than 60 % of these essential oils were considered active (LC50<100 mg/L), and the majority of these active oils were derived from species belonging to Myrtaceae, Lamiaceae, and Rutaceae. The most active essential oils exhibited effective concentrations comparable with the dosage recommended for the use of temephos in container breeding. Approximately 27 % of the plants studied for their larvicidal activity against A. aegypti were collected in Brazil. Essential oils rich in phenylpropanoids, oxygenated sesquiterpenes, and monoterpene hydrocarbons were found to be the most active. When the isolates were tested, phenylpropanoids and monoterpene hydrocarbons were the most active compound classes. We describe the plant parts used and the major constituents of the essential oils. In addition, we discuss factors affecting the activity (such as plant parts, age of the plant, chemotypes, larval source, and methods used), structure-activity relationships, and mechanisms of action of the essential oils and their compounds. Essential oils have been widely investigated and show high larvicidal activity against A. aegypti. This review reveals that the essential oils are effective alternatives for the production of larvicides, which can be used in vector-borne disease control programmes.

  13. Temephos Resistance in Aedes aegypti in Colombia Compromises Dengue Vector Control

    PubMed Central

    Grisales, Nelson; Poupardin, Rodolphe; Gomez, Santiago; Fonseca-Gonzalez, Idalyd; Ranson, Hilary; Lenhart, Audrey

    2013-01-01

    Background Control and prevention of dengue relies heavily on the application of insecticides to control dengue vector mosquitoes. In Colombia, application of the larvicide temephos to the aquatic breeding sites of Aedes aegypti is a key part of the dengue control strategy. Resistance to temephos was recently detected in the dengue-endemic city of Cucuta, leading to questions about its efficacy as a control tool. Here, we characterize the underlying mechanisms and estimate the operational impact of this resistance. Methodology/Principal Findings Larval bioassays of Ae. aegypti larvae from Cucuta determined the temephos LC50 to be 0.066 ppm (95% CI 0.06–0.074), approximately 15× higher than the value obtained from a susceptible laboratory colony. The efficacy of the field dose of temephos at killing this resistant Cucuta population was greatly reduced, with mortality rates <80% two weeks after application and <50% after 4 weeks. Neither biochemical assays nor partial sequencing of the ace-1 gene implicated target site resistance as the primary resistance mechanism. Synergism assays and microarray analysis suggested that metabolic mechanisms were most likely responsible for the temephos resistance. Interestingly, although the greatest synergism was observed with the carboxylesterase inhibitor, DEF, the primary candidate genes from the microarray analysis, and confirmed by quantitative PCR, were cytochrome P450 oxidases, notably CYP6N12, CYP6F3 and CYP6M11. Conclusions/Significance In Colombia, resistance to temephos in Ae. aegypti compromises the duration of its effect as a vector control tool. Several candidate genes potentially responsible for metabolic resistance to temephos were identified. Given the limited number of insecticides that are approved for vector control, future chemical-based control strategies should take into account the mechanisms underlying the resistance to discern which insecticides would likely lead to the greatest control efficacy while

  14. Essential oils and their compounds as Aedes aegypti L. (Diptera: Culicidae) larvicides: review.

    PubMed

    Dias, Clarice Noleto; Moraes, Denise Fernandes Coutinho

    2014-02-01

    This review aims to describe essential oils and their constituent compounds that exhibit bioactivity against Aedes aegypti L. (Diptera: Culicidae) larvae, the immature stage of the primary vector of dengue. This review is based on original articles obtained by searching on major databases. Our literature review revealed that 361 essential oils from 269 plant species have been tested for their larvicidal activity. More than 60 % of these essential oils were considered active (LC50<100 mg/L), and the majority of these active oils were derived from species belonging to Myrtaceae, Lamiaceae, and Rutaceae. The most active essential oils exhibited effective concentrations comparable with the dosage recommended for the use of temephos in container breeding. Approximately 27 % of the plants studied for their larvicidal activity against A. aegypti were collected in Brazil. Essential oils rich in phenylpropanoids, oxygenated sesquiterpenes, and monoterpene hydrocarbons were found to be the most active. When the isolates were tested, phenylpropanoids and monoterpene hydrocarbons were the most active compound classes. We describe the plant parts used and the major constituents of the essential oils. In addition, we discuss factors affecting the activity (such as plant parts, age of the plant, chemotypes, larval source, and methods used), structure-activity relationships, and mechanisms of action of the essential oils and their compounds. Essential oils have been widely investigated and show high larvicidal activity against A. aegypti. This review reveals that the essential oils are effective alternatives for the production of larvicides, which can be used in vector-borne disease control programmes. PMID:24265058

  15. Larval ecology of mosquitoes in sylvatic arbovirus foci in southeastern Senegal

    PubMed Central

    2012-01-01

    Background Although adult mosquito vectors of sylvatic arbovirus [yellow fever (YFV), dengue-2 (DENV-2) and chikungunya (CHIKV)] have been studied for the past 40 years in southeastern Senegal, data are still lacking on the ecology of larval mosquitoes in this area. In this study, we investigated the larval habitats of mosquitoes and characterized their seasonal and spatial dynamics in arbovirus foci. Methods We searched for wet microhabitats, classified in 9 categories, in five land cover classes (agriculture, forest, savannah, barren and village) from June, 2010 to January, 2011. Mosquito immatures were sampled monthly in up to 30 microhabitats of each category per land cover and bred until adult stage for determination. Results No wet microhabitats were found in the agricultural sites; in the remaining land covers immature stages of 35 mosquito species in 7 genera were sampled from 9 microhabitats (tree holes, fresh fruit husks, decaying fruit husks, puddles, bamboo holes, discarded containers, tires, rock holes and storage containers). The most abundant species was Aedes aegypti formosus, representing 30.2% of the collections, followed by 12 species, representing each more than 1% of the total, among them the arbovirus vectors Ae. vittatus (7.9%), Ae. luteocephalus (5.7%), Ae. taylori (5.0%), and Ae. furcifer (1.3%). Aedes aegypti, Cx. nebulosus, Cx. perfuscus, Cx. tritaeniorhynchus, Er. chrysogster and Ae. vittatus were the only common species collected from all land covers. Aedes furcifer and Ae. taylori were collected in fresh fruit husks and tree holes. Species richness and dominance varied significantly in land covers and microhabitats. Positive associations were found mainly between Ae. furcifer, Ae. taylori and Ae. luteocephalus. A high proportion of potential enzootic vectors that are not anthropophilic were found in the larval mosquito fauna. Conclusions In southeastern Senegal, Ae. furcifer and Ae. taylori larvae showed a more limited distribution

  16. Togavirus-associated pathologic changes in the midgut of a natural mosquito vector.

    PubMed Central

    Weaver, S C; Scott, T W; Lorenz, L H; Lerdthusnee, K; Romoser, W S

    1988-01-01

    Arthropod-borne viruses were not previously believed to cause discernible pathologic changes in their natural mosquito vectors. We report cytopathologic lesions in the midgut of the mosquito, Culiseta melanura, 2 to 5 days after oral infection with eastern equine encephalomyelitis virus. Sloughing of densely staining, heavily infected epithelial cells into the midgut lumen was observed by light and transmission electron microscopy, along with degeneration of cells within the epithelium. Pathological changes in midgut epithelial cells sometimes included loss of brush border and basal lamina integrity. Disruption of the midgut basal lamina could result in bypassing of barriers to virus dissemination within the mosquito and allow rapid transmission to occur. Alternatively, luminal sloughing of heavily infected midgut epithelial cells may serve to modulate mosquito infections. These findings challenge previous beliefs regarding the benign nature of arbovirus-invertebrate host relationships. Images PMID:2896802

  17. Ultrastructure and immunofluorescence of the midgut of Bombus morio (Hymenoptera: Apidae: Bombini).

    PubMed

    Gonçalves, Wagner Gonzaga; Fernandes, Kenner Morais; Barcellos, Marcelo Silva; Silva, Fernanda Pereira; Magalhães-Junior, Marcos Jorge; Zanuncio, José Cola; Martins, Gustavo Ferreira; Serrão, José Eduardo

    2014-06-01

    Bumblebees are widely distributed across the world and have great economic and ecological importance as pollinators in the forest as well as in agriculture. The insect midgut consists of three cell types, which play various important roles in digestion, absorption, and hormone production. The present study characterized the anterior and posterior midgut regions of the bumblebee, Bombus morio. The digestive, regenerative and endocrine cells in the midgut showed regional differences in their number, nuclear size, as well as the size of the striated border. Ultrastructurally, the digestive cells contained many mitochondria and long microvilli; however, in the anterior midgut region, these cells showed dilated basal labyrinths with a few openings for the hemocoel, whereas the labyrinths of the basal posterior region remained inverse characteristics. Thus, the characterization of the midgut of B. morio supported an ecto-endoperitrophic circulation, contributing to a better understanding of the digestive process in this bee.

  18. Togavirus-associated pathologic changes in the midgut of a natural mosquito vector.

    PubMed

    Weaver, S C; Scott, T W; Lorenz, L H; Lerdthusnee, K; Romoser, W S

    1988-06-01

    Arthropod-borne viruses were not previously believed to cause discernible pathologic changes in their natural mosquito vectors. We report cytopathologic lesions in the midgut of the mosquito, Culiseta melanura, 2 to 5 days after oral infection with eastern equine encephalomyelitis virus. Sloughing of densely staining, heavily infected epithelial cells into the midgut lumen was observed by light and transmission electron microscopy, along with degeneration of cells within the epithelium. Pathological changes in midgut epithelial cells sometimes included loss of brush border and basal lamina integrity. Disruption of the midgut basal lamina could result in bypassing of barriers to virus dissemination within the mosquito and allow rapid transmission to occur. Alternatively, luminal sloughing of heavily infected midgut epithelial cells may serve to modulate mosquito infections. These findings challenge previous beliefs regarding the benign nature of arbovirus-invertebrate host relationships.

  19. Larvicidal efficacies of plants from Midwestern Brazil: melianodiol from Guarea kunthiana as a potential biopesticide against Aedes aegypti

    PubMed Central

    Sarmento, Ulana Chaves; Miguita, Carlos Henrique; Almeida, Luís Henrique de Oliveira; Gaban, Cleusa Rocha Garcia; da Silva, Lilliam May Grespan Estodutto; de Souza, Albert Schiaveto; Garcez, Walmir Silva; Garcez, Fernanda Rodrigues

    2016-01-01

    A total of 36 ethanol extracts from different anatomical parts of 27 plant species (18 families), native to the Pantanal and Cerrado biomes in Midwest Brazil, was assessed for their effect against Aedes aegypti larvae, the vector of dengue, hemorrhagic dengue, Zika and chikungunya fevers. Only the extract obtained from seeds of Guarea kunthiana (Meliaceae) proved active (LC50 = 169.93 μg/mL). A bioassay-guided investigation of this extract led to the isolation and identification of melianodiol, a protolimonoid, as the active constituent (LC50 = 14.44 mg/mL). Meliantriol, which was also obtained from the bioactive fraction, was nevertheless devoid of any larval toxicity, even at the highest concentration tested (LC50 > 100.0 mg/mL). These results indicate that the larvicidal activity of melianodiol stems from the presence of the carbonyl moiety at C-3 in the 21,23-epoxy-21,24,25-trihydroxy-tirucall-7-ene-type skeleton. The structures of both protolimonoids were established on the basis of spectral methods (1H and 13C NMR and MS). This is the first report on the toxicity of melianodiol against Ae. aegypti larvae. Based on the results, melianodiol can be regarded as a potential candidate for use as an ecologically sound biocontrol agent for reducing the larval population of this vector. PMID:27333366

  20. Larvicidal efficacies of plants from Midwestern Brazil: melianodiol from Guarea kunthiana as a potential biopesticide against Aedes aegypti.

    PubMed

    Sarmento, Ulana Chaves; Miguita, Carlos Henrique; Almeida, Luís Henrique de Oliveira; Gaban, Cleusa Rocha Garcia; Silva, Lilliam May Grespan Estodutto da; Souza, Albert Schiaveto de; Garcez, Walmir Silva; Garcez, Fernanda Rodrigues

    2016-06-20

    A total of 36 ethanol extracts from different anatomical parts of 27 plant species (18 families), native to the Pantanal and Cerrado biomes in Midwest Brazil, was assessed for their effect against Aedes aegypti larvae, the vector of dengue, hemorrhagic dengue, Zika and chikungunya fevers. Only the extract obtained from seeds of Guarea kunthiana (Meliaceae) proved active (LC50 = 169.93 μg/mL). A bioassay-guided investigation of this extract led to the isolation and identification of melianodiol, a protolimonoid, as the active constituent (LC50 = 14.44 mg/mL). Meliantriol, which was also obtained from the bioactive fraction, was nevertheless devoid of any larval toxicity, even at the highest concentration tested (LC50 > 100.0 mg/mL). These results indicate that the larvicidal activity of melianodiol stems from the presence of the carbonyl moiety at C-3 in the 21,23-epoxy-21,24,25-trihydroxy-tirucall-7-ene-type skeleton. The structures of both protolimonoids were established on the basis of spectral methods (1H and 13C NMR and MS). This is the first report on the toxicity of melianodiol against Ae. aegypti larvae. Based on the results, melianodiol can be regarded as a potential candidate for use as an ecologically sound biocontrol agent for reducing the larval population of this vector. PMID:27333366

  1. Performance of Spodoptera litura Fabricius on different host plants: influence of nitrogen and total phenolics of plants and mid-gut esterase activity of the insect.

    PubMed

    Ghumare, S S; Mukherjee, S N

    2003-08-01

    Five host plants [castor, Ricinus communis (Carolus Linnaeus); cotton, Gossypium hirsutm (Carolus Linnaeus); tomato, Lycopersicum esculentum (Philip Miller); mint, Mentha arvensis (Carolus Linnaeus) and cabbage, Brassica oleracea (Carolus Linnaeus)] belonging to different families were used to study the performance of the Asian armyworm, Spodoptera litura larvae. Highest consumption of food and dry weight gain was observed in larvae fed on castor. Mint did not support optimum larval growth because of low digestibility and low efficiency of conversion of digested food to body matter. Dry weight gain ranged from 26.64 mg on mint to 86.80 mg in castor. These differences tend to be related to nitrogen and total phenolics content of the leaf tissues; however, the most clear-cut correlation is an inverse one between the host plant preference and the ratio of total phenolics to nitrogen in the leaf tissues. Mid-gut esterase activity in larvae showed an increasing trend with the increase in total phenolics: nitrogen ratio in the test plants and the order of mid-gut esterase activity in larvae was mint > cabbage > cotton > tomato > castor.

  2. Effects of neem oil (Azadirachta indica A. Juss) on midgut cells of predatory larvae Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae).

    PubMed

    Scudeler, Elton Luiz; dos Santos, Daniela Carvalho

    2013-01-01

    The effects of ingested neem oil, a botanical insecticide obtained from the seeds of the neem tree, Azadirachta indica, on the midgut cells of predatory larvae Ceraeochrysa claveri were analyzed. C. claveri were fed on eggs of Diatraea saccharalis treated with neem oil at a concentration of 0.5%, 1% and 2% during throughout the larval period. Light and electron microscopy showed severe damages in columnar cells, which had many cytoplasmic protrusions, clustering and ruptured of the microvilli, swollen cells, ruptured cells, dilatation and vesiculation of rough endoplasmic reticulum, development of smooth endoplasmic reticulum, enlargement of extracellular spaces of the basal labyrinth, intercellular spaces and necrosis. The indirect ingestion of neem oil with prey can result in severe alterations showing direct cytotoxic effects of neem oil on midgut cells of C. claveri larvae. Therefore, the safety of neem oil to non-target species as larvae of C. claveri was refuted, thus the notion that plants derived are safer to non-target species must be questioned in future ecotoxicological studies.

  3. Effects of soybean trypsin inhibitor on hypopharyngeal gland protein content, total midgut protease activity and survival of the honey bee (Apis mellifera L.).

    PubMed

    Sagili, Ramesh R; Pankiw, Tanya; Zhu-Salzman, Keyan

    2005-09-01

    Insecticidal properties of protease inhibitors have been established in transgenic plants. In the wake of continuous research and rapid development of protease inhibitors it is important to assess possible effects on beneficial insects like the honey bee (Apis mellifera L.). In this study, newly emerged caged bees were fed pollen diets containing three different concentrations (0.1%, 0.5% and 1% w:w) of soybean trypsin inhibitor (SBTI). Hypopharyngeal gland protein content, total midgut proteolytic enzyme activity of these bees, and survival were measured. Bees fed 1% SBTI had significantly reduced hypopharyngeal gland protein content and midgut proteolytic enzyme activity. There were no significant differences between control, 0.1% and 0.5% SBTI treatments. Bees fed a diet containing 1% SBTI had the lowest survival, followed by 0.5% and 0.1%, over a 30-day period. We concluded that nurse bees fed a pollen diet containing at least 1% SBTI would be poor producers of larval food, potentially threatening colony growth and maintenance. PMID:15927200

  4. Specificity of Bacillus thuringiensis endotoxins is correlated with the presence of high-affinity binding sites in the brush border membrane of target insect midguts

    SciTech Connect

    Hofmann, C.; Vanderbruggen, H.; Hoefte, H.; Van Rie, J.; Jansens, S.; Van Mellaert, H. )

    1988-11-01

    Binding studies were performed with two {sup 125}I-labeled Bacillus thuringiensis {delta}-endotoxins on brush border membrane vesicles prepared from the larval midgut of the tobacco hornworm Manduca sexta or the cabbage butterfly Pieris brassicae. One {delta}-endotoxin, Bt2-protoxin, is a 130-kDa recombinant crystalline protein from B. thuringiensis subsp. berliner. It kills larvae of both insect species. The active Bt2-toxin is a 60-kDa proteolytic fragment of the Bt2-protoxin. It binds saturably and with high affinity to brush border membrane vesicles from the midgut of both species. The other {delta}-endotoxin, Bt4412-protoxin, is a 136-kDa crystalline protein from B. thuringiensis subsp. thuringiensis, which is highly toxic for P. brassicae, but not for M. sexta larvae. Bt4412-toxin, obtained after proteolytic activation of Bt4412-protoxin, shows high-affinity saturable binding to P. brassicae vesicles but not to M. sexta vesicles. The correlation between toxicity and specific binding is further strengthened by competition studies. Other B. thuringiensis {delta}-endotoxins active against M. sexta compete for binding of {sup 125}I-labeled Bt2-toxin to M. sexta vesicles, whereas toxins active against dipteran or coleopteran larvae do not compete. Bt2-toxin and Bt4412-toxin bind to different sites on P. brassicae vesicles.

  5. Effects of neem oil (Azadirachta indica A. Juss) on midgut cells of predatory larvae Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae).

    PubMed

    Scudeler, Elton Luiz; dos Santos, Daniela Carvalho

    2013-01-01

    The effects of ingested neem oil, a botanical insecticide obtained from the seeds of the neem tree, Azadirachta indica, on the midgut cells of predatory larvae Ceraeochrysa claveri were analyzed. C. claveri were fed on eggs of Diatraea saccharalis treated with neem oil at a concentration of 0.5%, 1% and 2% during throughout the larval period. Light and electron microscopy showed severe damages in columnar cells, which had many cytoplasmic protrusions, clustering and ruptured of the microvilli, swollen cells, ruptured cells, dilatation and vesiculation of rough endoplasmic reticulum, development of smooth endoplasmic reticulum, enlargement of extracellular spaces of the basal labyrinth, intercellular spaces and necrosis. The indirect ingestion of neem oil with prey can result in severe alterations showing direct cytotoxic effects of neem oil on midgut cells of C. claveri larvae. Therefore, the safety of neem oil to non-target species as larvae of C. claveri was refuted, thus the notion that plants derived are safer to non-target species must be questioned in future ecotoxicological studies. PMID:22739123

  6. Performance of Spodoptera litura Fabricius on different host plants: influence of nitrogen and total phenolics of plants and mid-gut esterase activity of the insect.

    PubMed

    Ghumare, S S; Mukherjee, S N

    2003-08-01

    Five host plants [castor, Ricinus communis (Carolus Linnaeus); cotton, Gossypium hirsutm (Carolus Linnaeus); tomato, Lycopersicum esculentum (Philip Miller); mint, Mentha arvensis (Carolus Linnaeus) and cabbage, Brassica oleracea (Carolus Linnaeus)] belonging to different families were used to study the performance of the Asian armyworm, Spodoptera litura larvae. Highest consumption of food and dry weight gain was observed in larvae fed on castor. Mint did not support optimum larval growth because of low digestibility and low efficiency of conversion of digested food to body matter. Dry weight gain ranged from 26.64 mg on mint to 86.80 mg in castor. These differences tend to be related to nitrogen and total phenolics content of the leaf tissues; however, the most clear-cut correlation is an inverse one between the host plant preference and the ratio of total phenolics to nitrogen in the leaf tissues. Mid-gut esterase activity in larvae showed an increasing trend with the increase in total phenolics: nitrogen ratio in the test plants and the order of mid-gut esterase activity in larvae was mint > cabbage > cotton > tomato > castor. PMID:15248492

  7. Widespread evidence for interspecific mating between Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in nature.

    PubMed

    Bargielowski, I E; Lounibos, L P; Shin, D; Smartt, C T; Carrasquilla, M C; Henry, A; Navarro, J C; Paupy, C; Dennett, J A

    2015-12-01

    Aedes aegypti and Aedes albopictus, two important vectors of the dengue and chikungunya viruses to humans, often come in contact in their invasive ranges. In these circumstances, a number of factors are thought to influence their population dynamics, including resource competition among the larval stages, prevailing environmental conditions and reproductive interference in the form of satyrization. As the distribution and abundance of Ae. aegypti and Ae. albopictus have profound epidemiological implications, understanding the competitive interactions that influence these patterns in nature is important. While evidence for resource competition and environmental factors had been gathered from the field, the evidence for reproductive interference, though strongly inferred through laboratory trials, remained sparse (one small-scale field trial). In this paper we demonstrate that low rates (1.12-3.73%) of interspecific mating occur in nature among populations of these species that have co-existed sympatrically from 3 to 150yrs. Finally this report contributes a new species-specific primer set for identifying the paternity of sperm extracted from field collected specimens.

  8. Natural habitats of Aedes Aegypti in the Caribbean--a review.

    PubMed

    Chadee, D D; Ward, R A; Novak, R J

    1998-03-01

    Natural breeding habitats of Aedes aegypti in the Caribbean region were reviewed by conducting larval surveys in Trinidad. Puerto Rico, and the U.S. Virgin Islands and referring to records from the Mosquitoes of Middle America project. Twelve types of natural habitats were recorded: rock holes (9.7%), calabashes (2.4%), tree holes (19.5%), leaf axils (4.8%), bamboo joints (14.9%), papaya stumps (7.3%), coconut shells (4.8%), bromeliads (7.3%), ground pools (14.9%), coral rock holes (9.7%), crab holes (2.4%), and conch shells (7.3%), of which the coconut shell and calabash habitats were new to the Caribbean. The countries having the highest prevalence of natural habitats were Trinidad. Puerto Rico, and Jamaica, with 9 types (22.0%), 7 types (17.0%), and 6 types (14.6%), respectively. The distribution of natural habitats of Ae. aegypti in the Caribbean region is discussed in relation to vector control measures.

  9. A chitin-like component in Aedes aegypti eggshells, eggs and ovaries.

    PubMed

    Moreira, Mônica F; Dos Santos, Amanda S; Marotta, Humberto R; Mansur, Juliana F; Ramos, Isabela B; Machado, Ednildo A; Souza, Gustavo H M F; Eberlin, Marcos N; Kaiser, Carlos R; Kramer, Karl J; Muthukrishnan, Subbaratnam; Vasconcellos, Ana Maria H

    2007-12-01

    An insoluble white substance was prepared from extracts of eggshells of Aedes aegypti, the yellow fever mosquito and dengue vector. Its infrared and proton NMR spectra were similar to that of standard commercial chitin. This putative chitin-like material, also obtained from ovaries, newly laid and dark eggs, was hydrolyzed in acid and a major product was identified by HPLC to be glucosamine. The eggshell acid hydrolysate was also analyzed by ESI-MS and an ion identical to a glucosamine monoprotonated species was detected. The presence of chitin was also analyzed during different developmental stages of the ovary using a fluorescent microscopy technique and probes specific for chitin. The results showed that a chitin-like material accumulates in oocytes during oogenesis. Streptomyces griseus chitinase pre-treatment of oocytes greatly reduced the chitin-derived fluorescence. Chitinase activity was detected in newborn larvae and eggs prior to hatching. Feeding experiments indicated that the chitin synthesis inhibitor lufenuron inhibited chitin synthesis, either when mosquitoes were allowed to feed directly on lufenuron-treated chickens or when an artificial feeding system was used. Lufenuron inhibited egg hatch, larval development and reduced mosquito viability. These data demonstrate for the first time that (1) a chitin-like material is present in A. aegypti eggs, ovaries and eggshells; (2) a chitin synthesis inhibitor can be used to inhibit mosquito oogenesis; and (3) chitin synthesis inhibitors have potential for controlling mosquito populations. PMID:17967344

  10. Bionomics of Aedes aegypti subpopulations (Diptera: Culicidae) from Misiones Province, northeastern Argentina.

    PubMed

    Tejerina, Edmundo Fabricio; Almeida, Francisco Felipe Ludueña; Almirón, Walter Ricardo

    2009-01-01

    Life statistics of four Aedes aegypti subpopulations from the subtropical province of Misiones were studied during autumn and winter, under semi-natural conditions, coming from the localities of Posadas (SW), San Javier (SE), Bernardo de Irigoyen (NE) and Puerto Libertad (NW). The eastern subpopulations are geographically separated by the central mountain system of the province from the western subpopulations. High percentages of larval and pupal survival (97-100%) were recorded, and no significant differences were detected among the four subpopulations. Larvae and pupae lasted approximately 8 days to complete their development, no significant differences being detected among the four subpopulations studied. Sex ratio recorded did not differ significantly from 1:1. Male longevity did not show difference among the different subpopulations, but female longevity was remarkably different among the four subpopulations (F=16.27; d.f.=(3;8); P=0.0009), ranging among 11.45 days for San Javier and 57.87 days for Posadas. Fecundity also varied considerably among subpopulations, the greatest number (307.44 eggs/female) being recorded for Posadas (F=4.13; d.f.=(3;8); P=0.04). Ae. aegypti females of the western subpopulations lived longer than the eastern subpopulations studied, therefore, the risk of dengue outbreak would be greater on the Misiones Province border with Paraguay.

  11. The Premise Condition Index: a tool for streamlining surveys of Aedes aegypti.

    PubMed

    Tun-Lin, W; Kay, B H; Barnes, A

    1995-12-01

    Premise inspections and treatment of the larval habitats of container-breeding Aedes aegypti are extremely labor intensive. Since this means of control is the only one available in relation to dengue fever, this report presents an effective approach for streamlining premise surveys in north Queensland, Australia. From a survey of 877 premises in Townsville, Charters Towers, and Mingela/Ravenswood in 1990, occupier and premise variables were collected to examine any relationships with the presence of Ae. aegypti. Statistical modeling of these parameters using multiple and simple Poisson regression indicated that for both adjusted and unadjusted models respectively, the degree of shade and tidiness of the yard had strong correlations with both the proportion of positive premises and the numbers of infested containers therein. Condition of the house was also a significant variable in the unadjusted model. On this basis, the Premise Condition Index is proposed as a rapid assessment tool that can increase efficiency of detecting positive premises and containers by 270-370%. Although habitat selection by Aedes varies throughout the world, this approach could be used as a model for control of vectors of both dengue and yellow fever.

  12. Natural habitats of Aedes Aegypti in the Caribbean--a review.

    PubMed

    Chadee, D D; Ward, R A; Novak, R J

    1998-03-01

    Natural breeding habitats of Aedes aegypti in the Caribbean region were reviewed by conducting larval surveys in Trinidad. Puerto Rico, and the U.S. Virgin Islands and referring to records from the Mosquitoes of Middle America project. Twelve types of natural habitats were recorded: rock holes (9.7%), calabashes (2.4%), tree holes (19.5%), leaf axils (4.8%), bamboo joints (14.9%), papaya stumps (7.3%), coconut shells (4.8%), bromeliads (7.3%), ground pools (14.9%), coral rock holes (9.7%), crab holes (2.4%), and conch shells (7.3%), of which the coconut shell and calabash habitats were new to the Caribbean. The countries having the highest prevalence of natural habitats were Trinidad. Puerto Rico, and Jamaica, with 9 types (22.0%), 7 types (17.0%), and 6 types (14.6%), respectively. The distribution of natural habitats of Ae. aegypti in the Caribbean region is discussed in relation to vector control measures. PMID:9599318

  13. A tetraspanin regulates septate junction formation in Drosophila midgut.

    PubMed

    Izumi, Yasushi; Motoishi, Minako; Furuse, Kyoko; Furuse, Mikio

    2016-03-15

    Septate junctions (SJs) are membrane specializations that restrict the free diffusion of solutes through the paracellular pathway in invertebrate epithelia. In arthropods, two morphologically different types of septate junctions are observed; pleated (pSJs) and smooth (sSJs), which are present in ectodermally and endodermally derived epithelia, respectively. Recent identification of sSJ-specific proteins, Mesh and Ssk, in Drosophila indicates that the molecular compositions of sSJs and pSJs differ. A deficiency screen based on immunolocalization of Mesh identified a tetraspanin family protein, Tsp2A, as a newly discovered protein involved in sSJ formation in Drosophila Tsp2A specifically localizes at sSJs in the midgut and Malpighian tubules. Compromised Tsp2A expression caused by RNAi or the CRISPR/Cas9 system was associated with defects in the ultrastructure of sSJs, changed localization of other sSJ proteins, and impaired barrier function of the midgut. In most Tsp2A mutant cells, Mesh failed to localize to sSJs and was distributed through the cytoplasm. Tsp2A forms a complex with Mesh and Ssk and these proteins are mutually interdependent for their localization. These observations suggest that Tsp2A cooperates with Mesh and Ssk to organize sSJs. PMID:26848177

  14. Tsetse EP Protein Protects the Fly Midgut from Trypanosome Establishment

    PubMed Central

    Haines, Lee R.; Lehane, Stella M.; Pearson, Terry W.; Lehane, Michael J.

    2010-01-01

    African trypanosomes undergo a complex developmental process in their tsetse fly vector before transmission back to a vertebrate host. Typically, 90% of fly infections fail, most during initial establishment of the parasite in the fly midgut. The specific mechanism(s) underpinning this failure are unknown. We have previously shown that a Glossina-specific, immunoresponsive molecule, tsetse EP protein, is up regulated by the fly in response to gram-negative microbial challenge. Here we show by knockdown using RNA interference that this tsetse EP protein acts as a powerful antagonist of establishment in the fly midgut for both Trypanosoma brucei brucei and T. congolense. We demonstrate that this phenomenon exists in two species of tsetse, Glossina morsitans morsitans and G. palpalis palpalis, suggesting tsetse EP protein may be a major determinant of vector competence in all Glossina species. Tsetse EP protein levels also decline in response to starvation of the fly, providing a possible explanation for increased susceptibility of starved flies to trypanosome infection. As starvation is a common field event, this fact may be of considerable importance in the epidemiology of African trypanosomiasis. PMID:20221444

  15. Analysis of Drosophila larval feeding response to quinine-adulterated food.

    PubMed

    Shen, Ping

    2012-08-01

    The food responses of Drosophila larvae offer an excellent opportunity to study the genetic and neural regulation of feeding behavior. Compared with fed larvae, hungry larvae are more likely to display aggressive foraging, rapid food intake, compensatory feeding, and stress-resistant food procurement. Omnivores, including humans, tend to avoid noxious or unfamiliar food. Fly larvae avoid bitter substances such as quinine. As an increasing amount of quinine is added to an otherwise palatable liquid medium containing sugar and inactivated yeast, larvae become less likely to consume the tainted food. Larval feeding activity is assayed by scoring the percentage of larvae containing dyed food in a large portion of the midgut. Defensive foraging behavior can be modulated by physiological need and food deprivation significantly increases larval tolerance to quinine. Therefore, the larval response to quinine food and its regulation by hunger provides a useful paradigm for elucidating the genetic and neural regulation of food choice that favors short-term survival. The test described here is designed for quantitative assessment of the motivation of individual larvae to ingest quinine-adulterated food under different energy states. The test is applicable to routine functional testing and larger-scale screening of genetic mutations and biologics that might affect food consumption.

  16. Evaluation of some aromatic plant extracts for mosquito larvicidal potential against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    PubMed

    Jayaraman, M; Senthilkumar, A; Venkatesalu, V

    2015-04-01

    In the present investigation, larvicidal potential of hexane, choloroform, ethyl acetate, acetone, and methanol extracts of seven aromatic plants, viz., Blumea mollis, Chloroxylon swietenia, Clausena anisata, Feronia limnonia, Lantana camera, Plectranthus amboinicus, and Tagetes erecta were screened against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that all the extracts showed varied levels of larvicidal activity against the mosquito species tested. However, the ethyl acetate extract of Chloroxylon swietenia showed the remarkable larvicidal activity against C. quinquefasciatus, Ae. aegypti, and An. stephensi. After 12 h of exposure period, the larvicidal activity was LC50 = 194.22 and LC90 = 458.83 ppm (C. quinquefasciatus), LC50 = 173.04 and LC90 = 442.73 ppm (Ae. aegypti), and LC50 = 167.28 and LC90 = 433.07 ppm (An. stephensi), and the larvicidal activity after 24-h exposure period was LC50 = 94.12 and LC90 = 249.83 ppm (C. quinquefasciatus), LC50 = 80.58 and LC90 = 200.96 ppm (Ae. aegypti), and LC50 = 76.24 and LC90 = 194.51 ppm (An. stephensi). The larvicidal potential of other plant extracts were in order of ethyl acetate extract of Clausena anisata > methanol extract of P. amboinicus > acetone extract of F. limonia > methanol extract of T. erecta > methanol extract of B. mollis > and methanol extract of L. camera. The results of the present study offer a possible way for further investigations to find out the active molecule responsible for the activity. PMID:25630696

  17. Effect of two commercial herbicides on life history traits of a human disease vector, Aedes aegypti, in the laboratory setting.

    PubMed

    Morris, Alexandra; Murrell, Ebony G; Klein, Talan; Noden, Bruce H

    2016-07-01

    Some mosquito species utilize the small niches of water that are abundant in farmland habitats. These niches are susceptible to effects from agricultural pesticides, many of which are applied aerially over large tracts of land. One principal form of weed control in agricultural systems involves the development of herbicide-tolerant crops. The impact of sub-agricultural levels of these herbicides on mosquito survival and life-history traits of resulting adults have not been determined. The aim of this study was to test the effect of two commercial herbicides (Beyond and Roundup) on the survivorship, eclosion time, and body mass of Aedes aegypti. First instar A. aegypti larvae were exposed to varying concentrations (270, 550 and 820 μg/m(2) of glyphosate and 0.74, 1.49, 2.24 μL imazamox/m(2)), all treatments being below recommended application rates, of commercial herbicides in a controlled environment and resulting adult mosquitoes were collected and weighed. Exposure to Roundup had a significant negative effect on A. aegypti survivorship at medium and high sub-agricultural application concentrations, and negatively affected adult eclosion time at the highest concentration. However, exposure to low concentrations of Beyond significantly increased A. aegypti survivorship, although adult female mass was decreased at medium sub-agricultural concentrations. These results demonstrate that low concentrations of two different herbicides, which can occur in rural larval habitats as a result of spray drift, can affect the same species of mosquito in both positive and negative ways depending on the herbicide applied. The effects of commercial herbicides on mosquito populations could have an important effect on disease transmission within agricultural settings, where these and other herbicides are extensively applied to reduce weed growth.

  18. Effect of two commercial herbicides on life history traits of a human disease vector, Aedes aegypti, in the laboratory setting.

    PubMed

    Morris, Alexandra; Murrell, Ebony G; Klein, Talan; Noden, Bruce H

    2016-07-01

    Some mosquito species utilize the small niches of water that are abundant in farmland habitats. These niches are susceptible to effects from agricultural pesticides, many of which are applied aerially over large tracts of land. One principal form of weed control in agricultural systems involves the development of herbicide-tolerant crops. The impact of sub-agricultural levels of these herbicides on mosquito survival and life-history traits of resulting adults have not been determined. The aim of this study was to test the effect of two commercial herbicides (Beyond and Roundup) on the survivorship, eclosion time, and body mass of Aedes aegypti. First instar A. aegypti larvae were exposed to varying concentrations (270, 550 and 820 μg/m(2) of glyphosate and 0.74, 1.49, 2.24 μL imazamox/m(2)), all treatments being below recommended application rates, of commercial herbicides in a controlled environment and resulting adult mosquitoes were collected and weighed. Exposure to Roundup had a significant negative effect on A. aegypti survivorship at medium and high sub-agricultural application concentrations, and negatively affected adult eclosion time at the highest concentration. However, exposure to low concentrations of Beyond significantly increased A. aegypti survivorship, although adult female mass was decreased at medium sub-agricultural concentrations. These results demonstrate that low concentrations of two different herbicides, which can occur in rural larval habitats as a result of spray drift, can affect the same species of mosquito in both positive and negative ways depending on the herbicide applied. The effects of commercial herbicides on mosquito populations could have an important effect on disease transmission within agricultural settings, where these and other herbicides are extensively applied to reduce weed growth. PMID:26965703

  19. Evaluation of some aromatic plant extracts for mosquito larvicidal potential against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    PubMed

    Jayaraman, M; Senthilkumar, A; Venkatesalu, V

    2015-04-01

    In the present investigation, larvicidal potential of hexane, choloroform, ethyl acetate, acetone, and methanol extracts of seven aromatic plants, viz., Blumea mollis, Chloroxylon swietenia, Clausena anisata, Feronia limnonia, Lantana camera, Plectranthus amboinicus, and Tagetes erecta were screened against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that all the extracts showed varied levels of larvicidal activity against the mosquito species tested. However, the ethyl acetate extract of Chloroxylon swietenia showed the remarkable larvicidal activity against C. quinquefasciatus, Ae. aegypti, and An. stephensi. After 12 h of exposure period, the larvicidal activity was LC50 = 194.22 and LC90 = 458.83 ppm (C. quinquefasciatus), LC50 = 173.04 and LC90 = 442.73 ppm (Ae. aegypti), and LC50 = 167.28 and LC90 = 433.07 ppm (An. stephensi), and the larvicidal activity after 24-h exposure period was LC50 = 94.12 and LC90 = 249.83 ppm (C. quinquefasciatus), LC50 = 80.58 and LC90 = 200.96 ppm (Ae. aegypti), and LC50 = 76.24 and LC90 = 194.51 ppm (An. stephensi). The larvicidal potential of other plant extracts were in order of ethyl acetate extract of Clausena anisata > methanol extract of P. amboinicus > acetone extract of F. limonia > methanol extract of T. erecta > methanol extract of B. mollis > and methanol extract of L. camera. The results of the present study offer a possible way for further investigations to find out the active molecule responsible for the activity.

  20. Population structure of the mosquito Aedes aegypti (Stegomyia aegypti) in Pakistan.

    PubMed

    Rasheed, S B; Boots, M; Frantz, A C; Butlin, R K

    2013-12-01

    Eleven microsatellite markers were used to determine the genetic population structure and spread of Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) in Pakistan using mosquitoes collected from 13 different cities. There is a single genetic cluster of Ae. aegypti in Pakistan with a pattern of isolation by distance within the population. The low level of isolation by distance suggests the long-range passive dispersal of this mosquito, which may be facilitated by the tyre trade in Pakistan. A decrease in genetic diversity from south to north suggests a recent spread of this mosquito from Karachi. A strong negative correlation between genetic distance and the quality of road connections shows that populations in cities connected by better road networks are less differentiated, which suggests the human-aided passive dispersal of Ae. aegypti in Pakistan. Dispersal on a large spatial scale may facilitate the strategy of introducing transgenic Ae. aegypti or intracellular bacteria such as Wolbachia to control the spread of dengue disease in Pakistan, but it also emphasizes the need for simple measures to control container breeding sites.

  1. A NOVEL CADHERIN-LIKE GENE FROM WESTERN CORN ROOTWORM, DIABROTICA VIRGIFERA VIRGIFERA (COLEOPTERA: CHRYSOMELIDAE), LARVAL MIDGUT TISSUE

    EPA Science Inventory

    A cadherin-like gene and its mRNA were cloned from western corn rootworm (Diabrotica virgifera virgifera: Coleoptera), an economically important agricultural pest in North America and Europe. The full length cDNA (5371 bp in length) encodes an open reading frame for a 1688 amino ...

  2. Resistance to Bacillus thuringiensis by the Indian meal moth, Plodia interpunctella: comparison of midgut proteinases from susceptible and resistant larvae.

    PubMed

    Johnson, D E; Brookhart, G L; Kramer, K J; Barnett, B D; McGaughey, W H

    1990-03-01

    Midgut homogenates from susceptible and resistant strains of the Indian meal moth, Plodia interpunctella, were compared for their ability to activate the entomocidal parasporal crystal protein from Bacillus thuringiensis. The properties of midgut proteinases from both types of larvae were also examined. Electrophoretic patterns of crystal protein from B. thuringiensis subspecies kurstaki (HD-1) and aizawai (HD-133 and HD-144) were virtually unchanged following digestion by either type of midgut homogenate. Changes in pH (9.5 to 11.5) or midgut homogenate concentration during digestion failed to substantially alter protein electrophoretic patterns of B. thuringiensis HD-1 crystal toxin. In vitro toxicity of crystal protein activated by either type of midgut preparation was equal toward cultured insect cells from either Manduca sexta or Choristoneura fumiferana. Electrophoresis of midgut extracts in polyacrylamide gels containing gelatin as substrate also yielded matching mobility patterns of proteinases from both types of midguts. Quantitation of midgut proteolytic activity using tritiated casein as a substrate revealed variation between midgut preparations, but no statistically significant differences between proteolytic activities from susceptible and resistant Indian meal moth larvae. Inhibition studies indicated that a trypsin-like proteinase with maximal activity at pH 10 is a major constituent of Indian meal moth midguts. The results demonstrated that midguts from susceptible and resistant strains of P. interpunctella are similar both in their ability to activate B. thuringiensis protoxin and in their proteolytic activity.

  3. Analysis of molecular markers for metamorphic competency and their response to starvation or feeding in the mosquito, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Telang, A; Peterson, B; Frame, L; Baker, E; Brown, M R

    2010-12-01

    The nutritional condition of fourth instar larvae of the yellow fever mosquito, Aedes aegypti, governs female longevity and egg production, both are key determinants of pathogen transmission. As well, nutrition provisions larval growth and development and attains its greatest pace in the last larval instar in preparation for metamorphosis to an adult. These developmental processes are regulated by a complex endocrine interplay of juvenile hormone, neuropeptides, and ecdysteroids that is nutrition sensitive. We previously determined that feeding for only 24h post-ecdysis was sufficient for fourth instar Ae. aegypti larvae to reach critical weight and accumulate sufficient nutritional stores to commit to metamorphosis. To understand the genetic basis of metamorphic commitment in Ae. aegypti, we profiled the expression of 16 genes known to be involved in the endocrine and nutritional regulation of insect metamorphosis in two ways. The first set is a developmental profile from the beginning of the fourth instar to early pupae, and the second set is for fourth instars starved or fed for up to 36 h. By comparing the two sets, we found that seven of the genes (AaegCYP302, AaegJHE43357, AaegBrCZ4, AaegCPF1-2, AaegCPR-7, AaegPpl, and AaegSlif) were expressed during metamorphic commitment in fourth instars and in fed but not starved larvae. Based on these results, the seven genes alone or in combination may serve as molecular indicators of nutritional and metamorphic status of fourth instar Ae. aegypti larvae and possibly other mosquito species in field and laboratory studies to gauge sub-lethal effects of novel and traditional cultural or chemical controls.

  4. Ultrastructural changes of the midgut epithelium in Isohypsibius granulifer granulifer Thulin, 1928 (Tardigrada: Eutardigrada) during oogenesis.

    PubMed

    Rost-Roszkowska, Magdalena M; Poprawa, Izabela; Wójtowicz, Maria; Kaczmarek, Lukasz

    2011-04-01

    The midgut epithelium of Isohypsibius granulifer granulifer (Eutardigrada) is composed of columnar digestive cells. At its anterior end, a group of cells with cytoplasm which differs from the cytoplasm of digestive cells is present. Probably, those cells respond to crescent-like cells (midgut regenerative cells) described for some tardigrade species. Their mitotic divisions have not been observed. We analyzed the ultrastructure of midgut digestive cells in relation to five different stages of oogenesis (previtellogenesis, beginning of the vitellogenesis, vitellogenesis--early choriogenesis, vitellogenesis--middle choriogenesis, late choriogenesis). In the midgut epithelium cells, the gradual accumulation of glycogen granules, lipid droplets and structures of varying electron density occurs. During vitellogenesis and choriogenesis, in the cytoplasm of midgut cells we observed the increasing number of organelles which are responsible for the intensive synthesis of lipids, proteins and saccharides such as cisterns of endoplasmic reticulum and Golgi complexes. At the end of oogenesis, autophagy also intensifies in midgut epithelial cells, which is probably caused by the great amount of reserve material. Midgut epithelium of analyzed species takes part in the yolk precursor synthesis. PMID:20661605

  5. Altered protoxin activation by midgut enzymes from a Bacillus thuringiensis resistant strain of Plodia interpunctella.

    PubMed

    Oppert, B; Kramer, K J; Johnson, D E; MacIntosh, S C; McGaughey, W H

    1994-02-15

    Processing of Bacillus thuringiensis protoxins to toxins by midgut proteinases from a strain of the Indianmeal moth, Plodia interpunctella (Hubner), resistant to B. thuringiensis subspecies entomocidus (HD-198) was slower than that by midgut proteinases from the susceptible parent strain or a strain resistant to B. thuringiensis subspecies kurstaki (HD-1, Dipel). Midgut extracts from entomocidus-resistant insects exhibited five-fold lower activity toward the synthetic substrate alpha-N-benzoyl-DL-arginine rho-nitroanilide than extracts from susceptible or kurstaki-resistant insects. Midgut enzymes from susceptible or kurstaki-resistant insects converted the 133 kDa CryIA(c) protoxin to 61-63 kDa proteins, while incubations with entomocidus-resistant enzymes resulted in predominantly products of intermediate size, even with increased amounts of midgut extract. The 61-63 kDa proteins were only produced by entomocidus-resistant midgut extracts after long term incubations with the protoxin. The data suggest that altered protoxin activation by midgut proteinases is involved in some types of insect resistance to B. thuringiensis.

  6. Ultrastructural changes of the midgut epithelium in Isohypsibius granulifer granulifer Thulin, 1928 (Tardigrada: Eutardigrada) during oogenesis.

    PubMed

    Rost-Roszkowska, Magdalena M; Poprawa, Izabela; Wójtowicz, Maria; Kaczmarek, Lukasz

    2011-04-01

    The midgut epithelium of Isohypsibius granulifer granulifer (Eutardigrada) is composed of columnar digestive cells. At its anterior end, a group of cells with cytoplasm which differs from the cytoplasm of digestive cells is present. Probably, those cells respond to crescent-like cells (midgut regenerative cells) described for some tardigrade species. Their mitotic divisions have not been observed. We analyzed the ultrastructure of midgut digestive cells in relation to five different stages of oogenesis (previtellogenesis, beginning of the vitellogenesis, vitellogenesis--early choriogenesis, vitellogenesis--middle choriogenesis, late choriogenesis). In the midgut epithelium cells, the gradual accumulation of glycogen granules, lipid droplets and structures of varying electron density occurs. During vitellogenesis and choriogenesis, in the cytoplasm of midgut cells we observed the increasing number of organelles which are responsible for the intensive synthesis of lipids, proteins and saccharides such as cisterns of endoplasmic reticulum and Golgi complexes. At the end of oogenesis, autophagy also intensifies in midgut epithelial cells, which is probably caused by the great amount of reserve material. Midgut epithelium of analyzed species takes part in the yolk precursor synthesis.

  7. Antioxidant defenses in caterpillars: role of the ascorbate-recycling system in the midgut lumen.

    PubMed

    Barbehenn, R V; Bumgarner, S L; Roosen, E F; Martin, M M

    2001-04-01

    This study demonstrates that an ascorbate-recycling system in the midgut lumen can act as an effective antioxidant defense in caterpillars that feed on prooxidant-rich foods. In tannin-sensitive larvae of the forest tent caterpillar, Malacosoma disstria (Lasiocampidae), ingested tannic acid is oxidized in the midgut lumen, generating significant quantities of peroxides, including hydrogen peroxide, which readily diffuses across cell membranes and is a powerful cytotoxin. By contrast, in the tannin-tolerant larvae of the white-marked tussock moth, Orgyia leucostigma (Lymantriidae), tannic acid oxidation and the generation of peroxides are suppressed. The superior defense of O. leucostigma against oxidative stress imposed by the oxidation of ingested polyphenols can be explained by the presence of higher concentrations of ascorbate and glutathione in the midgut lumen. In O. leucostigma at least 50% of the ingested ascorbate present in the anterior midgut is still present in the posterior midgut, whereas in M. disstria, only 10% of the ascorbate is present in the posterior half of the midgut. We propose that the maintenance of higher levels of ascorbate in the midgut lumen of O. leucostigma than in M. disstria is explained by the secretion of glutathione into the midgut lumen by O. leucostigma, thereby forming a complete ascorbate-recycling system. The concentration of glutathione in the midgut lumen of O. leucostigma is 3.5-fold higher than in M. disstria and more than double the concentration in the diet. Our results emphasize the importance of a defensive strategy in herbivorous insects based on the maintenance of conditions in the gut lumen that reduce or eliminate the potential prooxidant behavior of ingested phenols.

  8. Localisation of laminin within Plasmodium berghei oocysts and the midgut epithelial cells of Anopheles stephensi

    PubMed Central

    Nacer, Adéla; Walker, Karen; Hurd, Hilary

    2008-01-01

    Background Oocysts of the malaria parasite form and develop in close proximity to the mosquito midgut basal lamina and it has been proposed that components of this structure play a crucial role in the development and maturation of oocysts that produce infective sporozoites. It is further suggested that oocysts incorporate basal lamina proteins into their capsule and that this provides them with a means to evade recognition by the mosquito's immune system. The site of production of basal lamina proteins in insects is controversial and it is still unclear whether haemocytes or midgut epithelial cells are the main source of components of the mosquito midgut basal lamina. Of the multiple molecules that compose the basal lamina, laminin is known to interact with a number of Plasmodium proteins. In this study, the localisation of mosquito laminin within the capsule and cytoplasm of Plasmodium berghei oocysts and in the midgut epithelial cells of Anopheles stephensi was investigated. Results An ultrastructural examination of midgut sections from infected and uninfected An. stephensi was performed. Post-embedded immunogold labelling demonstrated the presence of laminin within the mosquito basal lamina. Laminin was also detected on the outer surface of the oocyst capsule, incorporated within the capsule and associated with sporozoites forming within the oocysts. Laminin was also found within cells of the midgut epithelium, providing support for the hypothesis that these cells contribute towards the formation of the midgut basal lamina. Conclusion We suggest that ookinetes may become coated in laminin as they pass through the midgut epithelium. Thereafter, laminin secreted by midgut epithelial cells and/or haemocytes, binds to the outer surface of the oocyst capsule and that some passes through and is incorporated into the developing oocysts. The localisation of laminin on sporozoites was unexpected and the importance of this observation is less clear. PMID:18808667

  9. Compartmentalization of proteinases and amylases in Nauphoeta cinerea midgut.

    PubMed

    Elpidina, E N; Vinokurov, K S; Gromenko, V A; Rudenskaya, Y A; Dunaevsky, Y E; Zhuzhikov, D P

    2001-12-01

    Compartmentalization of proteinases, amylases, and pH in the midgut of Nauphoeta cinerea Oliv. (Blattoptera:Blaberidae) was studied in order to understand the organization of protein and starch digestion. Total proteolytic activity measured with azocasein was maximal at pH 11.5 both in anterior (AM) and posterior (PM) halves of the midgut, but the bulk of activity (67%) was found in PM. Total AM and PM preparations were fractionated on a Sephadex G-50 column and further analysed by means of activity electrophoresis and specific inhibitors and activators. The major activity in PM was classified as an unusual SH-dependent proteinase with M(r) 24,000 and pH optimum with synthetic substrate BApNA at 10.0. The enzyme was 43-fold activated in the presence of 1 mM DTT, insensitive to synthetic inhibitors of serine (PMSF, TLCK, TPCK) and cysteine (IAA, E-64) proteinases, strongly inhibited by STI, and displayed four active bands on zymograms. In PM, activities of trypsin-like, chymotrypsin-like, subtilisin-like, and cysteine proteinases were observed. Aspartic and metalloproteinases were not detected. In AM, activity of unusual SH-dependent proteinase also dominated and activity of chymotrypsin-like proteinase was observed, but their levels were much lower than in PM. Distribution of amylase activity, exhibiting an optimum at pH 6.0, was quite the opposite. The major part of it (67%) was located in AM. Treatment of amylase preparation with proteinases from AM and PM reduced amylase activity twofold. pH of the midgut contents was 6.0-7.2 in AM, 6.4-7.6 in the first and 8.8-9.3 in the second halves of PM. Thus, pH in AM is in good agreement with the optimal pH of amylase, located in this compartment, but the activity of proteinases, including the ability to degrade amylase, in such an environment is low. Active proteolysis takes place in the second half of PM, where pH of the gut is close to the optimal pH of proteinases.

  10. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality

    PubMed Central

    Alkhaibari, Abeer M.; Carolino, Aline T.; Yavasoglu, Sare I.; Maffeis, Thierry; Mattoso, Thalles C.; Bull, James C.; Samuels, Richard I.; Butt, Tariq M.

    2016-01-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world’s population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti

  11. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality.

    PubMed

    Alkhaibari, Abeer M; Carolino, Aline T; Yavasoglu, Sare I; Maffeis, Thierry; Mattoso, Thalles C; Bull, James C; Samuels, Richard I; Butt, Tariq M

    2016-07-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world's population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti larvae

  12. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality.

    PubMed

    Alkhaibari, Abeer M; Carolino, Aline T; Yavasoglu, Sare I; Maffeis, Thierry; Mattoso, Thalles C; Bull, James C; Samuels, Richard I; Butt, Tariq M

    2016-07-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world's population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti larvae

  13. Pyrosequencing the Midgut Transcriptome of the Banana Weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) Reveals Multiple Protease-Like Transcripts.

    PubMed

    Valencia, Arnubio; Wang, Haichuan; Soto, Alberto; Aristizabal, Manuel; Arboleda, Jorge W; Eyun, Seong-Il; Noriega, Daniel D; Siegfried, Blair

    2016-01-01

    The banana weevil Cosmopolites sordidus is an important and serious insect pest in most banana and plantain-growing areas of the world. In spite of the economic importance of this insect pest very little genomic and transcriptomic information exists for this species. In the present study, we characterized the midgut transcriptome of C. sordidus using massive 454-pyrosequencing. We generated over 590,000 sequencing reads that assembled into 30,840 contigs with more than 400 bp, representing a significant expansion of existing sequences available for this insect pest. Among them, 16,427 contigs contained one or more GO terms. In addition, 15,263 contigs were assigned an EC number. In-depth transcriptome analysis identified genes potentially involved in insecticide resistance, peritrophic membrane biosynthesis, immunity-related function and defense against pathogens, and Bacillus thuringiensis toxins binding proteins as well as multiple enzymes involved with protein digestion. This transcriptome will provide a valuable resource for understanding larval physiology and for identifying novel target sites and management approaches for this important insect pest. PMID:26949943

  14. Pyrosequencing the Midgut Transcriptome of the Banana Weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) Reveals Multiple Protease-Like Transcripts.

    PubMed

    Valencia, Arnubio; Wang, Haichuan; Soto, Alberto; Aristizabal, Manuel; Arboleda, Jorge W; Eyun, Seong-Il; Noriega, Daniel D; Siegfried, Blair

    2016-01-01

    The banana weevil Cosmopolites sordidus is an important and serious insect pest in most banana and plantain-growing areas of the world. In spite of the economic importance of this insect pest very little genomic and transcriptomic information exists for this species. In the present study, we characterized the midgut transcriptome of C. sordidus using massive 454-pyrosequencing. We generated over 590,000 sequencing reads that assembled into 30,840 contigs with more than 400 bp, representing a significant expansion of existing sequences available for this insect pest. Among them, 16,427 contigs contained one or more GO terms. In addition, 15,263 contigs were assigned an EC number. In-depth transcriptome analysis identified genes potentially involved in insecticide resistance, peritrophic membrane biosynthesis, immunity-related function and defense against pathogens, and Bacillus thuringiensis toxins binding proteins as well as multiple enzymes involved with protein digestion. This transcriptome will provide a valuable resource for understanding larval physiology and for identifying novel target sites and management approaches for this important insect pest.

  15. Pyrosequencing the Midgut Transcriptome of the Banana Weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) Reveals Multiple Protease-Like Transcripts

    PubMed Central

    Valencia, Arnubio; Wang, Haichuan; Soto, Alberto; Aristizabal, Manuel; Arboleda, Jorge W.; Eyun, Seong-il; Noriega, Daniel D.; Siegfried, Blair

    2016-01-01

    The banana weevil Cosmopolites sordidus is an important and serious insect pest in most banana and plantain-growing areas of the world. In spite of the economic importance of this insect pest very little genomic and transcriptomic information exists for this species. In the present study, we characterized the midgut transcriptome of C. sordidus using massive 454-pyrosequencing. We generated over 590,000 sequencing reads that assembled into 30,840 contigs with more than 400 bp, representing a significant expansion of existing sequences available for this insect pest. Among them, 16,427 contigs contained one or more GO terms. In addition, 15,263 contigs were assigned an EC number. In-depth transcriptome analysis identified genes potentially involved in insecticide resistance, peritrophic membrane biosynthesis, immunity-related function and defense against pathogens, and Bacillus thuringiensis toxins binding proteins as well as multiple enzymes involved with protein digestion. This transcriptome will provide a valuable resource for understanding larval physiology and for identifying novel target sites and management approaches for this important insect pest. PMID:26949943

  16. Importance of ecology in Aedes aegypti control.

    PubMed

    Service, M W

    1992-12-01

    Aedes aegypti is one of the world's most widely distributed mosquitos and is of considerable medical importance as a vector of dengue and yellow fever. Not surprisingly therefore there has been more written on its biology than any other mosquito. The present paper summarizes ecological studies undertaken on this vector, including those on pre-adult mortalities, life-tables, adult dispersal and survival rates. In discussing surveillance techniques it is pointed out there are still no reliable methods for monitoring adult populations. The importance of the resting habits of adults and house construction in insecticidal control of Ae. aegypti is discussed. The question is, have ecological studies and population modeling resulted in any more understanding of the epidemiology of dengue, or helped formulate better control strategies? The answer seems to be not usually, possible because there have actually been relatively few good ecological studies on Ae. aegypti. Although mathematical modeling indicates that better control might be achieved if it were directed at the larvae, not adults, this has not usually been taken into consideration by those engaged in control. There is clearly need for greater collaboration between those practicing control, and ecologists and modelers.

  17. Identification of chemical constituents and larvicidal activity of essential oil from Murraya exotica L. (Rutaceae) against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Krishnamoorthy, Shanmugam; Chandrasekaran, Manivachagam; Raj, Gnanaprakasam Adaikala; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-05-01

    This study was conducted to evaluate the phytochemical composition and larvicidal effect of leaf essential oil from Murraya exotica against early fourth-instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS) analyses revealed that the essential oil contained 27 components. The major chemical components identified were β-humulene (40.62%), benzyl benzoate (23.96%), β-caryophyllene (7.05%) and α-terpinene (5.66%). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that essential oil showed varied levels of larvicidal activity against A. aegypti, A. stephensi and C. quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC₅₀ = 74.7 and LC₉₀ = 152.7 ppm (A. aegypti), LC₅₀ = 56.3 and LC₉₀ = 107.8 ppm (A. stephensi ), and LC₅₀ = 74.4 and LC₉₀ = 136.9 ppm (C. quinquefasciatus) and the larvicidal activities after 24 h of exposure period were LC₅₀ = 35.8 and LC₉₀ = 85.4 ppm (A. aegypti), LC₅₀ = 31.3 and LC₉₀ = 75.1 ppm (A. stephensi), and LC₅₀ = 43.2 and LC₉₀ = 103.2 ppm (C. quinquefasciatus). These results suggest that leaf essential oil from M. exotica is a promising and eco-friendly source of natural larvicidal agent against A. aegypti, A. stephensi and C. quinquefasciatus. PMID:25697880

  18. Identification of chemical constituents and larvicidal activity of essential oil from Murraya exotica L. (Rutaceae) against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Krishnamoorthy, Shanmugam; Chandrasekaran, Manivachagam; Raj, Gnanaprakasam Adaikala; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-05-01

    This study was conducted to evaluate the phytochemical composition and larvicidal effect of leaf essential oil from Murraya exotica against early fourth-instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS) analyses revealed that the essential oil contained 27 components. The major chemical components identified were β-humulene (40.62%), benzyl benzoate (23.96%), β-caryophyllene (7.05%) and α-terpinene (5.66%). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that essential oil showed varied levels of larvicidal activity against A. aegypti, A. stephensi and C. quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC₅₀ = 74.7 and LC₉₀ = 152.7 ppm (A. aegypti), LC₅₀ = 56.3 and LC₉₀ = 107.8 ppm (A. stephensi ), and LC₅₀ = 74.4 and LC₉₀ = 136.9 ppm (C. quinquefasciatus) and the larvicidal activities after 24 h of exposure period were LC₅₀ = 35.8 and LC₉₀ = 85.4 ppm (A. aegypti), LC₅₀ = 31.3 and LC₉₀ = 75.1 ppm (A. stephensi), and LC₅₀ = 43.2 and LC₉₀ = 103.2 ppm (C. quinquefasciatus). These results suggest that leaf essential oil from M. exotica is a promising and eco-friendly source of natural larvicidal agent against A. aegypti, A. stephensi and C. quinquefasciatus.

  19. Toxicity effect of Delonix elata (Yellow Gulmohr) and predatory efficiency of Copepod, Mesocyclops aspericornis for the control of dengue vector, Aedes aegypti

    PubMed Central

    Vasugi, Chellamuthu; Kamalakannan, Siva; Murugan, Kadarkarai

    2013-01-01

    Objective To evaluate the toxicity, predatory efficiency of Delonix elata (D. elata) and Mesocyclops aspericornis (M. aspericornis) against dengue vector, Aedes aegypti (Ae. aegypti). Methods A mosquitocidal bioassay was conducted at different concentration of plant extract followed by WHO standard method. The probit analysis of each tested concentration and control were observed by using software SPSS 11 version package. The each tested concentration variable was assessed by DMRT method. The predatory efficiency of copepod was followed by Deo et al., 1988. The predator, M. aspericornis was observed for mortality, abnormalities, survival and swimming activity after 24 h treatment of plant and also predation on the mosquito larvae were observed. Results D. elata were tested for biological activity against the larvae, and pupae of Ae. aegypti. Significant mortality effects were observed in each life stage. The percentage of mortality was 100% in first and second instars whereas 96%, 92% in third and fourth instars. Fitted probit-mortality curves for larvae indicated the median and 90% lethal concentrations of D. elata for instars 1-4 to be 4.91 (8.13), 5.16 (8.44), 5.95 (7.76) and 6.87 (11.23), respectively. The results indicate that leaf extract exhibits significant biological activity against life stages. The present study revealed that D. elata is potentially important in the control of Ae. aegypti. Similar studies were conducted for predatory efficiency of Copepod, M. aspericornis against mosquito vector Ae. Aegypti. This study reported that the predatory copepod fed on 39% and 25% in I and III instar larvae of mosquito and in combined treatment of D. elata and copepod maximum control of mosquito larval states and at 83%, 80%, 75% and 53% in I, II, III and IV instars, respectively. Conclusions The combined action of plant extract and predatory copepod to effectively control mosquito population and reduce the dengue transmitting diseases.

  20. Fitness costs of resistance to Bti toxins in the dengue vector Aedes aegypti.

    PubMed

    Paris, Margot; David, Jean-Philippe; Despres, Laurence

    2011-08-01

    Sustainable insect vector disease control strategies involve delaying the evolution of resistance to insecticides in natural populations. The evolutionary dynamics of resistance in the field is highly dependent on the fitness cost of resistance alleles. To successfully manage resistance evolution in target species, it is not only important to find evidence of fitness cost in resistant insects, but also to determine at which stage of the insect's life it is expressed. Here, we show that resistance costs to the bacterio-insecticide Bacillus thuringiensis subsp. israelensis (Bti) are expressed at all the life-stages of the dengue vector Aedes aegypti, including egg survival, larval development time, and female fecundity. We show that the storage of eggs for 4 months is long enough to counter-select resistance alleles. This suggests that Bti resistance is not likely to evolve in temperate climates where most mosquito species overwinter as eggs. In tropical regions with a rapid turn-over of generations, resistance alleles are likely to be counter-selected in only few generations without treatment through fitness costs expressed in terms of larval development time and female fecundity. We discuss the implications of our findings in terms of sustainable management strategies in light of the challenge of preserving the long-term efficiency of this environmentally safe anti-mosquito bio-insecticide.

  1. Studies on the life budget of Aedes aegypti in Wat Samphaya, Bangkok, Thailand.

    PubMed

    Southwood, T R; Murdie, G; Yasuno, M; Tonn, R J; Reader, P M

    1972-01-01

    For a complete understanding of the epidemiology of a vector-borne disease, a knowledge of the bionomics of the vector is needed. The development of Aedes aegypti was studied in Wat Samphaya, Bangkok, Thailand, where work on the adult biology had been carried out the previous year (1966-67). Particular attention was given to the variation in the numbers of immature stages of the mosquito in relation to the known seasonal incidence of dengue haemorrhagic fever. Of the three types of water container in the Wat, water jars were the main source of adults, flower pot plates were less important, and the contribution of ant traps was insignificant.The variation in the numbers of emerging adults depended on changes in the mortality of the immature stages rather than on variations in the numbers of eggs laid. Both early and late larval instar mortalities are important, the former becoming more significant during the period March-August. The mortality between the eggs and second-instar larvae is density-dependent. There was no clear trend of association between mortality and season except for a fall in larval mortality in April-May preceding the increase in annual incidence of haemorrhagic fever, which usually occurs in June.

  2. Cruzipain Promotes Trypanosoma cruzi Adhesion to Rhodnius prolixus Midgut

    PubMed Central

    Uehara, Lívia Almeida; Moreira, Otacílio C.; Oliveira, Ana Carolina; Azambuja, Patrícia; Lima, Ana Paula Cabral Araujo; Britto, Constança; dos Santos, André Luis Souza; Branquinha, Marta Helena; d'Avila-Levy, Claudia Masini

    2012-01-01

    Background Trypanosoma cruzi is the etiological agent of Chagas' disease. Cysteine peptidases are relevant to several aspects of the T. cruzi life cycle and are implicated in parasite-mammalian host relationships. However, little is known about the factors that contribute to the parasite-insect host interaction. Methodology/Principal Findings Here, we have investigated whether cruzipain could be involved in the interaction of T. cruzi with the invertebrate host. We analyzed the effect of treatment of T. cruzi epimastigotes with anti-cruzipain antibodies or with a panel of cysteine peptidase inhibitors (cystatin, antipain, E-64, leupeptin, iodocetamide or CA-074-OMe) on parasite adhesion to Rhodnius prolixus posterior midgut ex vivo. All treatments, with the exception of CA074-OMe, significantly decreased parasite adhesion to R. prolixus midgut. Cystatin presented a dose-dependent reduction on the adhesion. Comparison of the adhesion rate among several T. cruzi isolates revealed that the G isolate, which naturally possesses low levels of active cruzipain, adhered to a lesser extent in comparison to Dm28c, Y and CL Brener isolates. Transgenic epimastigotes overexpressing an endogenous cruzipain inhibitor (pCHAG), chagasin, and that have reduced levels of active cruzipain adhered to the insect gut 73% less than the wild-type parasites. The adhesion of pCHAG parasites was partially restored by the addition of exogenous cruzipain. In vivo colonization experiments revealed low levels of pCHAG parasites in comparison to wild-type. Parasites isolated after passage in the insect presented a drastic enhancement in the expression of surface cruzipain. Conclusions/Significance These data highlight, for the first time, that cruzipain contributes to the interaction of T. cruzi with the insect host. PMID:23272264

  3. Assembling of Holotrichia parallela (dark black chafer) midgut tissue transcriptome and identification of midgut proteins that bind to Cry8Ea toxin from Bacillus thuringiensis.

    PubMed

    Shu, Changlong; Tan, Shuqian; Yin, Jiao; Soberón, Mario; Bravo, Alejandra; Liu, Chunqing; Geng, Lili; Song, Fuping; Li, Kebin; Zhang, Jie

    2015-09-01

    Holotrichia parallela is one of the most severe crop pests in China, affecting peanut, soybean, and sweet potato crops. Previous work showed that Cry8Ea toxin is highly effective against this insect. In order to identify Cry8Ea-binding proteins in the midgut cells of H. parallela larvae, we assembled a midgut tissue transcriptome by high-throughput sequencing and used this assembled transcriptome to identify Cry8Ea-binding proteins by liquid chromatography-tandem mass spectrometry (LC-MS/MS). First, we obtained de novo sequences of cDNAs from midgut tissue of H. parallela larvae and used available cDNA data in the GenBank. In a parallel assay, we obtained 11 Cry8Ea-binding proteins by pull-down assays performed with midgut brush border membrane vesicles. Peptide sequences from these proteins were matched to the H. parallela newly assembled midgut transcriptome, and 10 proteins were identified. Some of the proteins were shown to be intracellular proteins forming part of the cell cytoskeleton and/or vesicle transport such as actin, myosin, clathrin, dynein, and tubulin among others. In addition, an apolipophorin, which is a protein involved in lipid metabolism, and a novel membrane-bound alanyl aminopeptidase were identified. Our results suggest that Cry8Ea-binding proteins could be different from those characterized for Cry1A toxins in lepidopteran insects. PMID:26135984

  4. Reappearance of Aedes aegypti (Diptera: Culicidae) in Lima, Peru.

    PubMed

    Andrade, C S; Cáceres, A G; Vaquerizo, A; Ibañez-Bernal, S; Cachay, L S

    2001-07-01

    We report here the reappearance of Aedes aegypti in the Rimac district, and summarize the history of this mosquito species in Peru since its first detection in 1852. On March 17 2000 were found Ae. aegypti and Culex quinquefasciatus in Mariscal Castilla town, Flor de Amancaes, San Juan de Amancaes, El Altillo and Santa Rosa in the Rimac district, Lima Province. PMID:11500764

  5. Productivity and population density estimates of the dengue vector mosquito Aedes aegypti (Stegomyia aegypti) in Australia.

    PubMed

    Williams, C R; Johnson, P H; Ball, T S; Ritchie, S A

    2013-09-01

    New mosquito control strategies centred on the modifying of populations require knowledge of existing population densities at release sites and an understanding of breeding site ecology. Using a quantitative pupal survey method, we investigated production of the dengue vector Aedes aegypti (L.) (Stegomyia aegypti) (Diptera: Culicidae) in Cairns, Queensland, Australia, and found that garden accoutrements represented the most common container type. Deliberately placed 'sentinel' containers were set at seven houses and sampled for pupae over 10 weeks during the wet season. Pupal production was approximately constant; tyres and buckets represented the most productive container types. Sentinel tyres produced the largest female mosquitoes, but were relatively rare in the field survey. We then used field-collected data to make estimates of per premises population density using three different approaches. Estimates of female Ae. aegypti abundance per premises made using the container-inhabiting mosquito simulation (CIMSiM) model [95% confidence interval (CI) 18.5-29.1 females] concorded reasonably well with estimates obtained using a standing crop calculation based on pupal collections (95% CI 8.8-22.5) and using BG-Sentinel traps and a sampling rate correction factor (95% CI 6.2-35.2). By first describing local Ae. aegypti productivity, we were able to compare three separate population density estimates which provided similar results. We anticipate that this will provide researchers and health officials with several tools with which to make estimates of population densities.

  6. Comparison of midgut bacterial diversity in tropical caterpillars (Lepidoptera: Saturniidae) fed on different diets.

    PubMed

    Pinto-Tomás, Adrián A; Sittenfeld, Ana; Uribe-Lorío, Lorena; Chavarría, Felipe; Mora, Marielos; Janzen, Daniel H; Goodman, Robert M; Simon, Holly M

    2011-10-01

    As primary consumers of foliage, caterpillars play essential roles in shaping the trophic structure of tropical forests. The caterpillar midgut is specialized in plant tissue processing; its pH is exceptionally alkaline and contains high concentrations of toxic compounds derived from the ingested plant material (secondary compounds or allelochemicals) and from the insect itself. The midgut, therefore, represents an extreme environment for microbial life. Isolates from different bacterial taxa have been recovered from caterpillar midguts, but little is known about the impact of these microorganisms on caterpillar biology. Our long-term goals are to identify midgut symbionts and to investigate their functions. As a first step, different diet formulations were evaluated for rearing two species of tropical saturniid caterpillars. Using the polymerase chain reaction (PCR) with primers hybridizing broadly to sequences from the bacterial domain, 16S rRNA gene libraries were constructed with midgut DNA extracted from caterpillars reared on different diets. Amplified rDNA restriction analysis indicated that bacterial sequences recovered from the midguts of caterpillars fed on foliage were more diverse than those from caterpillars fed on artificial diet. Sequences related to Methylobacterium sp., Bradyrhizobium sp., and Propionibacterium sp. were detected in all caterpillar libraries regardless of diet, but were not detected in a library constructed from the diet itself. Furthermore, libraries constructed with DNA recovered from surface-sterilized eggs indicated potential for vertical transmission of midgut symbionts. Taken together, these results suggest that microorganisms associated with the tropical caterpillar midgut may engage in symbiotic interactions with these ecologically important insects.

  7. Plant Defense Inhibitors Affect the Structures of Midgut Cells in Drosophila melanogaster and Callosobruchus maculatus.

    PubMed

    Li-Byarlay, Hongmei; Pittendrigh, Barry R; Murdock, Larry L

    2016-01-01

    Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus. We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster. Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant-insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology. PMID:27594789

  8. The midgut epithelium of aquatic arthropods: a critical target organ in environmental toxicology.

    PubMed Central

    Beaty, Barry J; Mackie, Ryan S; Mattingly, Kimberly S; Carlson, Jonathan O; Rayms-Keller, Alfredo

    2002-01-01

    The midgut epithelium of aquatic arthropods is emerging as an important and toxicologically relevant organ system for monitoring environmental pollution. The peritrophic matrix of aquatic arthropods, which is secreted by the midgut epithelium cells, is perturbed by copper or cadmium. Molecular biological studies have identified and characterized two midgut genes induced by heavy metals in the midgut epithelium. Many other metal-responsive genes (MRGs) await characterization. One of the MRGs codes for an intestinal mucin, which is critical for protecting the midgut from toxins and pathogens. Another codes for a tubulin gene, which is critical for structure and function of the midgut epithelial cells. Perturbation of expression of either gene could condition aquatic arthropod survivorship. Induction of these MRGs is a more sensitive and rapid indicator of heavy-metal pollution than biological assays. Characterization of genes induced by pollutants could provide mechanistic understanding of fundamental cellular responses to pollutants and insight into determinants of aquatic arthropod population genetic structure and survivorship in nature. PMID:12634118

  9. Plant Defense Inhibitors Affect the Structures of Midgut Cells in Drosophila melanogaster and Callosobruchus maculatus

    PubMed Central

    Li-Byarlay, Hongmei; Pittendrigh, Barry R.; Murdock, Larry L.

    2016-01-01

    Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus. We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster. Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant–insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology. PMID:27594789

  10. Implications of Time Bomb model of ookinete invasion of midgut cells.

    PubMed

    Han, Yeon Soo; Barillas-Mury, Carolina

    2002-10-01

    In this review, we describe the experimental observations that led us to propose the Time Bomb model of ookinete midgut invasion and discuss potential implications of this model when considering malaria transmission-blocking strategies aimed at arresting parasite development within midgut cells. A detailed analysis of the molecular interactions between Anopheles stephensi midgut epithelial cells and Plasmodium berghei parasites, as they migrate through midgut cells, revealed that ookinetes induce nitric oxide synthase (NOS) expression, remodeling of the actin cytoskeleton and characteristic morphological changes in the invaded epithelial cells. Parasites inflict extensive damage that ultimately leads to genome fragmentation and cell death. During their migration through the cytoplasm, ookinetes release a subtilisin-like protease (PbSub2) and the surface protein (Pbs21). The model proposes that ookinetes must escape rapidly from the invaded cells, as the responses mediating cell death could be potentially lethal to the parasites. In other words, the physical and/or chemical damage triggered by the parasite can be thought of as a 'lethal bomb'. Once this cascade of events is initiated, the parasite must leave the cellular compartment within a limited time to escape unharmed from the 'bomb' it has activated. The midgut epithelium has the ability to heal rapidly by 'budding off' the damaged cells to the midgut lumen without losing its integrity. PMID:12225921

  11. Plant Defense Inhibitors Affect the Structures of Midgut Cells in Drosophila melanogaster and Callosobruchus maculatus

    PubMed Central

    Li-Byarlay, Hongmei; Pittendrigh, Barry R.; Murdock, Larry L.

    2016-01-01

    Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus. We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster. Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant–insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology.

  12. Midgut of the non-hematophagous mosquito Toxorhynchites theobaldi (Diptera, Culicidae).

    PubMed

    Godoy, Raquel S M; Fernandes, Kenner M; Martins, Gustavo F

    2015-10-30

    In most mosquito species, the females require a blood-feeding for complete egg development. However, in Toxorhynchites mosquitoes, the eggs develop without blood-feeding, and both females and males exclusively feed on sugary diets. The midgut is a well-understood organ in blood-feeding mosquitoes, but little is known about it in non-blood-feeding ones. In the present study, the detailed morphology of the midgut of Toxorhynchites theobaldi were investigated using histochemical and ultrastructural methods. The midgut of female and male T. theobaldi adults consists of a long, slender anterior midgut (AMG), and a short, dilated posterior midgut (PMG). The AMG is subdivided into AMG1 (short, with folds) and AMG2 (long, without folds). Nerve branches and enteroendocrine cells are present in AMG and PMG, respectively. Compared with the PMG of blood-feeding female mosquitoes, the PMG of T. theobaldi is smaller; however, in both mosquitoes, PMG seems be the main region of food digestion and absorption, and protein secretion. The epithelial folds present in the AMG of T. theobaldi have not been reported in other mosquitoes; however, the midgut muscle organization and endocrine control of the digestion process are conserved in both T. theobaldi and blood-feeding mosquitoes.

  13. Midgut of the non-hematophagous mosquito Toxorhynchites theobaldi (Diptera, Culicidae)

    PubMed Central

    Godoy, Raquel S. M.; Fernandes, Kenner M.; Martins, Gustavo F.

    2015-01-01

    In most mosquito species, the females require a blood-feeding for complete egg development. However, in Toxorhynchites mosquitoes, the eggs develop without blood-feeding, and both females and males exclusively feed on sugary diets. The midgut is a well-understood organ in blood-feeding mosquitoes, but little is known about it in non-blood-feeding ones. In the present study, the detailed morphology of the midgut of Toxorhynchites theobaldi were investigated using histochemical and ultrastructural methods. The midgut of female and male T. theobaldi adults consists of a long, slender anterior midgut (AMG), and a short, dilated posterior midgut (PMG). The AMG is subdivided into AMG1 (short, with folds) and AMG2 (long, without folds). Nerve branches and enteroendocrine cells are present in AMG and PMG, respectively. Compared with the PMG of blood-feeding female mosquitoes, the PMG of T. theobaldi is smaller; however, in both mosquitoes, PMG seems be the main region of food digestion and absorption, and protein secretion. The epithelial folds present in the AMG of T. theobaldi have not been reported in other mosquitoes; however, the midgut muscle organization and endocrine control of the digestion process are conserved in both T. theobaldi and blood-feeding mosquitoes. PMID:26514271

  14. Anti-dengue efficacy of bioactive andrographolide from Andrographis paniculata (Lamiales: Acanthaceae) against the primary dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Edwin, Edward-Sam; Vasantha-Srinivasan, Prabhakaran; Senthil-Nathan, Sengottayan; Thanigaivel, Annamalai; Ponsankar, Athirstam; Pradeepa, Venkatraman; Selin-Rani, Selvaraj; Kalaivani, Kandaswamy; Hunter, Wayne B; Abdel-Megeed, Ahmed; Duraipandiyan, Veeramuthu; Al-Dhabi, Naif Abdullah

    2016-11-01

    The current study investigated the toxic effect of the leaf extract compound andrographolide from Andrographis paniculata (Burm.f) against the dengue vector Ae. aegypti. GC-MS analysis revealed that andrographolide was recognized as the major chemical constituent with the prominent peak area compared with other compounds. All isolated toxic compounds were purified and confirmed through RP-HPLC against chemical standards. The larvicidal assays established at 25ppm of bioactive compound against the treated instars of Ae. Aegypti showed prominent mortality compared to other treated concentrations. The percent mortality of larvae was directly proportional to concentration. The lethal concentration (LC50) was observed at 12ppm treatment concentration. The bioactive andrographolide considerably reduced the detoxifying enzyme regulations of α- and β- carboxylesterases. In contrast, the levels of GST and CYP450 significantly increase in a dose dependent manner. The andrographolide also showed strong oviposition deterrence effects at the sub-lethal dose of 12ppm. Similarly, the mean number of eggs were also significantly reduced in a dose dependent manner. At the concentration of 12ppm the effective percentage of repellency was greater than 90% with a protection time of 15-210min, compared with control. The histopathology study displayed that larvae treated with bioactive andrographolide had cytopathic effects in the midgut epithelium compared with the control. The present study established that bioactive andrographolide served as a potential useful for dengue vector management. PMID:27443607

  15. Effects of grapefruit (Citrus paradisi MACF) (Rutaceae) peel oil against developmental stages of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Ivoke, Njoku; Ogbonna, Priscilla C; Ekeh, Felicia N; Ezenwaji, Ngozi E; Atama, Chinedu I; Ejere, Vincent C; Onoja, Uwakwe S; Eyo, Joseph E

    2013-11-01

    Laboratory bioassay of the essential oil extracted from the grapefruit (Citrus paradisi) peel by steam distillation was carried out against the developmental stages of the yellow fever vector Aedes aegypti to evaluate its toxicity, and ovicidal and larvicidal potency. Volatile oil components isolated and characterized by coupled gas chromatography/mass spectrometry included varying levels of monoterpene aldehydes, alcohols, and esters. Test results of the essential oil showed that egg hatching was completely inhibited at 400 ppm, while further development of 1st to 2nd larval stage was inhibited at 100 ppm. Regression analysis results also indicated that the peel essential oil significantly (p<0.01) reduced the viability of the test eggs and inhibited the development of 1st larval stage to 2nd larval instar. The LC50 and LC90 values obtained for 2nd instars (180.460, 334.629 ppm, respectively); and for 4th instars (210.937, 349.489 ppm, respectively) after 24-hour exposure were time but not dose dependent, as each LC value was a product of an inverse relationship between the oil concentration and exposure time. The results indicated that the peel oil could be a potent persistent larvicide. PMID:24450234

  16. Small Interfering RNA Pathway Modulates Initial Viral Infection in Midgut Epithelium of Insect after Ingestion of Virus

    PubMed Central

    Lan, Hanhong; Chen, Hongyan; Liu, Yuyan; Jiang, Chaoyang; Mao, Qianzhuo; Jia, Dongsheng; Chen, Qian

    2015-01-01

    ABSTRACT Numerous viruses are transmitted in a persistent manner by insect vectors. Persistent viruses establish their initial infection in the midgut epithelium, from where they disseminate to the midgut visceral muscles. Although propagation of viruses in insect vectors can be controlled by the small interfering RNA (siRNA) antiviral pathway, whether the siRNA pathway can control viral dissemination from the midgut epithelium is unknown. Infection by a rice virus (Southern rice black streaked dwarf virus [SRBSDV]) of its incompetent vector (the small brown planthopper [SBPH]) is restricted to the midgut epithelium. Here, we show that the siRNA pathway is triggered by SRBSDV infection in continuously cultured cells derived from the SBPH and in the midgut of the intact insect. Knockdown of the expression of the core component Dicer-2 of the siRNA pathway by RNA interference strongly increased the ability of SRBSDV to propagate in continuously cultured SBPH cells and in the midgut epithelium, allowing viral titers in the midgut epithelium to reach the threshold (1.99 × 109 copies of the SRBSDV P10 gene/μg of midgut RNA) needed for viral dissemination into the SBPH midgut muscles. Our results thus represent the first elucidation of the threshold for viral dissemination from the insect midgut epithelium. Silencing of Dicer-2 further facilitated the transmission of SRBSDV into rice plants by SBPHs. Taken together, our results reveal the new finding that the siRNA pathway can control the initial infection of the insect midgut epithelium by a virus, which finally affects the competence of the virus's vector. IMPORTANCE Many viral pathogens that cause significant global health and agricultural problems are transmitted via insect vectors. The first bottleneck in viral infection, the midgut epithelium, is a principal determinant of the ability of an insect species to transmit a virus. Southern rice black streaked dwarf virus (SRBSDV) is restricted exclusively to the

  17. What does not kill them makes them stronger: larval environment and infectious dose alter mosquito potential to transmit filarial worms

    PubMed Central

    Breaux, Jennifer A.; Schumacher, Molly K.; Juliano, Steven A.

    2014-01-01

    For organisms with complex life cycles, larval environments can modify adult phenotypes. For mosquitoes and other vectors, when physiological impacts of stressors acting on larvae carry over into the adult stage they may interact with infectious dose of a vector-borne pathogen, producing a range of phenotypes for vector potential. Investigation of impacts of a common source of stress, larval crowding and intraspecific competition, on adult vector interactions with pathogens may increase our understanding of the dynamics of pathogen transmission by mosquito vectors. Using Aedes aegypti and the nematode parasite Brugia pahangi, we demonstrate dose dependency of fitness effects of B. pahangi infection on the mosquito, as well as interactions between competitive stress among larvae and infectious dose for resulting adults that affect the physiological and functional ability of mosquitoes to act as vectors. Contrary to results from studies on mosquito–arbovirus interactions, our results suggest that adults from crowded larvae may limit infection better than do adults from uncrowded controls, and that mosquitoes from high-quality larval environments are more physiologically and functionally capable vectors of B. pahangi. Our results provide another example of how the larval environment can have profound effects on vector potential of resulting adults. PMID:24827444

  18. Mosquito Larvicidal Potential of Gossypium hirsutum (Bt cotton) Leaves Extracts against Aedes aegypti and Anopheles stephensi larvae

    PubMed Central

    Patil, Chandrashekhar D; Borase, Hemant P; Salunkhe, Rahul B; Suryawanshi, Rahul K; Narkhade, Chandrakant P; Salunke, Bipinchandra K; Patil, Satish V

    2014-01-01

    Background: We aimed to extract the ingredients from leaves of Gossypium hirsutum (Bt cotton) using different solvents and evaluate for potential use to control different larval stages of mosquito species, Aedes aegypti and Anopheles stephensi. Methods: Qualitative and quantitative estimation of ingredients from Go. hirsutum (Bt) plant extract was carried out and their inhibitory action against mosquito larvae was determined using mosquito larvicidal assay. Results: LC50 values of water, ethanol, ethyl acetate and hexane extracts for Ae. aegypti were 211.73±21.49, 241.64±19.92, 358.07±32.43, 401.03±36.19 and 232.56±26.00, 298.54±21.78, 366.50±30.59, 387.19±31.82 for 4th instar of An. stephensi, respectively. The water extract displayed lowest LC50 value followed by ethanol, ethyl acetate and hexane. Owing to the comparatively better activity of water extract, its efficacy was further evaluated for mosquito larvicidal activity, which exhibited LC50 values of 133.95±12.79, 167.65±11.34 against 2nd and 3rd instars of Ae. aegypti and 145.48±11.76, 188.10±12.92 against 2nd and 3rd instars of An. stephensi, respectively. Crude protein from the water extract was precipitated using acetone and tested against 2nd, 3rd and 4th instars of Ae. aegypti and An. stephensi. It revealed further decrease in LC50 values as 105.72±25.84, 138.23±23.18, 126.19±25.65, 134.04±04 and 137.88±17.59, 154.25±16.98 for 2nd, 3rd and 4th instars of Ae. aegypti and An. stephensi, respectively. Conclusion: Leaves extracts of Go. hirsutum (Bt) is potential mosquito larvicide and can be used as a potent alternative to chemical insecticides in integrated pest management. PMID:25629069

  19. Dynamics of Aedes aegypti and Culex quinquefasciatus in septic tanks.

    PubMed

    Mackay, Andrew J; Amador, Manuel; Diaz, Annette; Smith, Josh; Barrera, Roberto

    2009-12-01

    Aedes aegypti and Culex quinquefasciatus were found in large numbers emerging from septic tanks in southern Puerto Rico during the dry season. Previous studies suggested that Ae. aegypti uses subterranean aquatic habitats only during dry periods when surface containers do not have water. This research investigated whether septic tanks are alternative aquatic habitats that this mosquito uses during unfavorable times of the year, or whether Ae. aegypti uses this aquatic habitat throughout the year. To assess temporal change, exit traps were used to collect mosquitoes emerging from septic tanks in Playa/Playita, southern Puerto Rico, from November 2006 to October 2007. We also investigated the hypotheses that (1) the production of Ae. aegypti in septic tanks was larger than in surface containers and (2) adult mosquitoes emerging from septic tanks were larger than those emerging from surface containers. This study demonstrated that unsealed septic tanks produced large numbers of Ae. aegypti and Cx. quinquefasciatus throughout the year, without any significant relationship with rainfall. The number of adult Ae. aegypti emerging per day from septic tanks in each community was 3 to 9 times larger than those produced in surface containers. It was also demonstrated that Ae. aegypti emerging from septic tanks were significantly larger than those emerging from surface container habitats. It is recommended that dengue prevention programs include regular inspection and maintenance of septic tanks in communities lacking sewerage.

  20. Evaluation of the sticky MosquiTRAP for detecting Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) during the dry season in Belo Horizonte, Minas Gerais, Brazil.

    PubMed

    Gama, Renata A; Silva, Eric M; Silva, Ivoneide M; Resende, Marcelo C; Eiras, Alvaro E

    2007-01-01

    MosquiTRAP is a sticky trap specifically designed to capture gravid females of Aedes aegypti (L.) and allows the identification of the mosquito in the field during the inspection of the trap. This study aims to compare this sticky trap to larval and ovitrap surveys for field monitoring of A. aegypti during the dry season. The study was conducted from March to June of 2003 in 20 blocks of the district of Itapoã, Belo Horizonte, MG. The traps were monitored every week while the larval survey was conducted on a monthly basis. The larval index: Premise Index (PI) and Breteau Index (BI) had equal values throughout the experiment (1.72 in the first two months and zero in the last two). The container index (CI) during the first two months was 0.09 and 0.1%, respectively and zero in the last two. The Ovitrap Positive Index (OPI) ranged from 16.7 to 76.9%, and the MosquiTRAP Positive Index (MPI) ranged from 0 to 31.5%. The Egg Density Index (EDI) ranged from 26.6 to 82.8, while the Adult Density Index ranged from 0 to 1.6 throughout the experiment. Temperature and rainfall did not affect the Positive and Density Indices, although these environmental variables seemed to have affected the larvae indices. Although the MosquiTRAP caught a low number of Aedes mosquitoes during the study, it was more sensitive than the larval survey to detect the presence of Aedes mosquitoes. PMID:17607465

  1. Conidia of the insect pathogenic fungus, Metarhizium anisopliae, fail to adhere to mosquito larval cuticle

    PubMed Central

    Greenfield, Bethany P. J.; Lord, Alex M.; Dudley, Ed; Butt, Tariq M.

    2014-01-01

    Adhesion of conidia of the insect pathogenic fungus, Metarhizium anisopliae, to the arthropod host cuticle initially involves hydrophobic forces followed by consolidation facilitated by the action of extracellular enzymes and secretion of mucilage. Gene expression analysis and atomic force microscopy were used to directly quantify recognition and adhesion between single conidia of M. anisopliae and the cuticle of the aquatic larval stage of Aedes aegypti and a representative terrestrial host, Tenebrio molitor. Gene expression data indicated recognition by the pathogen of both hosts; however, the forces for adhesion to the mosquito were approximately five times lower than those observed for Tenebrio. Although weak forces were recorded in response to Aedes, Metarhizium was unable to consolidate firm attachment. An analysis of the cuticular composition revealed an absence of long-chain hydrocarbons in Aedes larvae which are thought to be required for fungal development on host cuticle. This study provides, to our knowledge, the first evidence that Metarhizium does not form firm attachment to Ae. aegypti larvae in situ, therefore preventing the normal route of invasion and pathogenesis from occuring. PMID:26064542

  2. Conidia of the insect pathogenic fungus, Metarhizium anisopliae, fail to adhere to mosquito larval cuticle.

    PubMed

    Greenfield, Bethany P J; Lord, Alex M; Dudley, Ed; Butt, Tariq M

    2014-10-01

    Adhesion of conidia of the insect pathogenic fungus, Metarhizium anisopliae, to the arthropod host cuticle initially involves hydrophobic forces followed by consolidation facilitated by the action of extracellular enzymes and secretion of mucilage. Gene expression analysis and atomic force microscopy were used to directly quantify recognition and adhesion between single conidia of M. anisopliae and the cuticle of the aquatic larval stage of Aedes aegypti and a representative terrestrial host, Tenebrio molitor. Gene expression data indicated recognition by the pathogen of both hosts; however, the forces for adhesion to the mosquito were approximately five times lower than those observed for Tenebrio. Although weak forces were recorded in response to Aedes, Metarhizium was unable to consolidate firm attachment. An analysis of the cuticular composition revealed an absence of long-chain hydrocarbons in Aedes larvae which are thought to be required for fungal development on host cuticle. This study provides, to our knowledge, the first evidence that Metarhizium does not form firm attachment to Ae. aegypti larvae in situ, therefore preventing the normal route of invasion and pathogenesis from occuring. PMID:26064542

  3. The dengue vector Aedes aegypti: what comes next.

    PubMed

    Jansen, Cassie C; Beebe, Nigel W

    2010-04-01

    Aedes aegypti is the urban vector of dengue viruses worldwide. While climate influences the geographical distribution of this mosquito species, other factors also determine the suitability of the physical environment. Importantly, the close association of A. aegypti with humans and the domestic environment allows this species to persist in regions that may otherwise be unsuitable based on climatic factors alone. We highlight the need to incorporate the impact of the urban environment in attempts to model the potential distribution of A. aegypti and we briefly discuss the potential for future technology to aid management and control of this widespread vector species.

  4. Measuring thigmotaxis in larval zebrafish.

    PubMed

    Schnörr, S J; Steenbergen, P J; Richardson, M K; Champagne, D L

    2012-03-17

    One of the most commonly used behavioral endpoints measured in preclinical studies using rodent models is thigmotaxis (or "wall-hugging"). Thigmotaxis is a well-validated index of anxiety in animals and humans. While assays measuring thigmotaxis in adult zebrafish have been developed, a thigmotaxis assay has not yet been validated in larval zebrafish. Here we present a novel assay for measurement of thigmotaxis in zebrafish larvae that is triggered by a sudden change in illumination (i.e. sudden light-to-darkness transition) and performed in a standard 24-well plate. We show that zebrafish larvae as young as 5 days post fertilization respond to this challenge by engaging in thigmotaxis. Thigmotaxis was significantly attenuated by anxiolytic (diazepam) and significantly enhanced by anxiogenic (caffeine) drugs, thus representing the first validated thigmotaxis assay for larval zebrafish. We also show that exposure to sudden darkness per se may represent an anxiogenic situation for larval zebrafish since less contrasting light-to-darkness transitions (achieved by lowering darkness degrees) significantly decreased thigmotaxis levels in a manner similar to what was achieved with diazepam. These findings suggest that stimuli such as exposure to sudden darkness could be used proficiently to trigger the expression of anxiety-like behaviors in laboratory settings. In sum, this is a versatile protocol allowing testing of both anxiolytic and anxiogenic drugs in a cost-effective manner (only 10 min). This assay is also amenable to medium to high-throughput capacity while constituting a valuable tool for stress and central nervous system research as well as for preclinical drug screening and discovery. PMID:22197677

  5. Laboratory and Simulated Field Bioassays to Evaluate Larvicidal Activity of Pinus densiflora Hydrodistillate, Its Constituents and Structurally Related Compounds against Aedes albopictus, Aedes aegypti and Culex pipiens pallens in Relation to Their Inhibitory Effects on Acetylcholinesterase Activity.

    PubMed

    Lee, Dong Chan; Ahn, Young-Joon

    2013-01-01

    The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, δ-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides.

  6. Laboratory and Simulated Field Bioassays to Evaluate Larvicidal Activity of Pinus densiflora Hydrodistillate, Its Constituents and Structurally Related Compounds against Aedes albopictus, Aedes aegypti and Culex pipiens pallens in Relation to Their Inhibitory Effects on Acetylcholinesterase Activity

    PubMed Central

    Lee, Dong Chan; Ahn, Young-Joon

    2013-01-01

    The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, δ-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides. PMID:26464387

  7. Prostaglandin biosynthesis by midgut tissue isolated from the tobacco hornworm, Manduca sexta.

    PubMed

    Büyükgüzel, K; Tunaz, H; Putnam, S M; Stanley, D

    2002-04-01

    We describe prostaglandin (PG) biosynthesis by isolated midgut preparations from tobacco hornworms, Manduca sexta. Microsomal-enriched midgut preparations yielded four PGs, PGA/B(2), PGD(2), PGE(2) and PGF(2alpha), all of which were confirmed by analysis on gas chromatography--mass spectrometry (GC--MS). PGA and PGB are double bond isomers which do not resolve on TLC but do resolve by GC; for convenience, we use the single term PGA(2) for this product. PGA(2) was the major product under most conditions. The midgut preparations were sensitive to reaction conditions, including radioactive substrate, protein concentration (optimal at 1mg/reaction), reaction time (optimal at 0.5 min), temperature (optimal at 22 degrees C), buffer pH (highest at pH 6), and the presence of a co-factor cocktail composed of reduced glutathione, hydroquinine and hemoglobin. In vitro PG biosynthesis was inhibited by two cyclooxygenase inhibitors, indomethacin and naproxen. Subcellular localization of PG biosynthetic activity in midgut preparations, determined by ultracentrifugation, revealed the presence of PG biosynthetic activity in the cytosolic and microsomal fractions, although most activity was found in the cytosolic fractions. This is similar to other invertebrates, and different from mammalian preparations, in which the activity is exclusively associated with the microsomal fractions. Midgut preparations from M. sexta pupae, adult cockroach, Periplaneta americana, and corn ear worms, Helicoverpa zea, also produced the same four major PG products. We infer that insect midguts are competent to biosynthesize PGs, and speculate they exert important, albeit unrevealed, actions in midgut physiology.

  8. Phytochemical profile and larvicidal properties of seed essential oil from Nigella sativa L. (Ranunculaceae), against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Raj, Gnanaprakasam Adaikala; Chandrasekaran, Manivachagam; Krishnamoorthy, Shanmugam; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-09-01

    The present study deals with investigation of larvicidal activity and their chemical constituents of the essential oil from the seeds of Nigella sativa L. (Ranunculaceae). Totally, 18 chemical compounds were identified by GC and GC-MS analysis. Thymol (19.13 %) and α-phellandrene (14.9 %) were identified as major chemical components followed by camphor (12.14 %), borneol (11.31 %), and carvacrol (8.65 %). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that the essential oil were evaluated against the fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC50 = 196.9 and LC90 = 523.5 ppm (A. aegypti), LC50 = 88.1 and LC90 = 272.4 ppm (A.stephensi), and LC50 = 241.6 and LC90 = 545.4 ppm (C. quinquefasciatus), and the larvicidal activities after 24 h of exposure period were LC50 = 99.9 and LC90 = 300.8 ppm (A. aegypti), LC50 = 53.9 and LC90 = 172.6 ppm (A. stephensi), and LC50 = 141.7 and LC90 = 364.0 ppm (C. quinquefasciatus). The results of the present study showed that the essential oil from seeds of N. sativa is inexpensive food formulation and new source of natural larvicidal agent. PMID:26091760

  9. Phytochemical profile and larvicidal properties of seed essential oil from Nigella sativa L. (Ranunculaceae), against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Raj, Gnanaprakasam Adaikala; Chandrasekaran, Manivachagam; Krishnamoorthy, Shanmugam; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-09-01

    The present study deals with investigation of larvicidal activity and their chemical constituents of the essential oil from the seeds of Nigella sativa L. (Ranunculaceae). Totally, 18 chemical compounds were identified by GC and GC-MS analysis. Thymol (19.13 %) and α-phellandrene (14.9 %) were identified as major chemical components followed by camphor (12.14 %), borneol (11.31 %), and carvacrol (8.65 %). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that the essential oil were evaluated against the fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC50 = 196.9 and LC90 = 523.5 ppm (A. aegypti), LC50 = 88.1 and LC90 = 272.4 ppm (A.stephensi), and LC50 = 241.6 and LC90 = 545.4 ppm (C. quinquefasciatus), and the larvicidal activities after 24 h of exposure period were LC50 = 99.9 and LC90 = 300.8 ppm (A. aegypti), LC50 = 53.9 and LC90 = 172.6 ppm (A. stephensi), and LC50 = 141.7 and LC90 = 364.0 ppm (C. quinquefasciatus). The results of the present study showed that the essential oil from seeds of N. sativa is inexpensive food formulation and new source of natural larvicidal agent.

  10. Evaluation of Household Bleach as an Ovicide for the Control of Aedes Aegypti

    PubMed Central

    Mackay, Andrew J.; Amador, Manuel; Felix, Gilberto; Acevedo, Veronica; Barrera, Roberto

    2015-01-01

    Accumulations of dormant eggs in container habitats allow Aedes aegypti populations to survive harsh environmental conditions and may frustrate control interventions directed at larval and adult life stages. While sodium hypochlorite solutions (NaOCl) have long been recognized as ovicides for use against dengue vectors, the susceptibility of eggs to spray applications has not been robustly evaluated on substrate materials representative of the most frequently utilized artificial container habitats. Experiments were performed under controlled and natural conditions by applying dilutions of household bleach (52.5 ppt NaOCl) as a spray to eggs on plastic, rubber, and concrete surfaces, with and without a smectite clay thickener. Laboratory assays identified the minimum NaOCl concentrations required to eliminate eggs on plastic (10 ppt), rubber (20 ppt) and concrete (20 ppt) surfaces. Addition of smectite clay reduced the minimum effective concentration to 10 ppt NaOCl for all 3 substrates. A minimum exposure period of 24 h was required to completely eliminate egg viability on concrete surfaces, even at the highest NaOCl concentration (52.5 ppt). Field experiments verified that spray application of a 1:3 dilution of household bleach mixed with smectite clay can reduce egg hatching by ≥ 99% in shaded and sun-exposed plastic containers. Similarly, 4:1 dilution of household bleach (with or without smectite clay) eliminated ≥ 98% of eggs from concrete surfaces in outdoor, water-filled drums. In this study, we propose a practical, effective and safe strategy for using household bleach to eliminate Ae. aegypti eggs in a range of artificial container habitats. PMID:25843179

  11. Evaluation of Household Bleach as an Ovicide for the Control of Aedes aegypti.

    PubMed

    Mackay, Andrew J; Amador, Manuel; Felix, Gilberto; Acevedo, Veronica; Barrera, Roberto

    2015-03-01

    Accumulations of dormant eggs in container habitats allow Aedes aegypti populations to survive harsh environmental conditions and may frustrate control interventions directed at larval and adult life stages. While sodium hypochlorite solutions (NaOCl) have long been recognized as ovicides for use against dengue vectors, the susceptibility of eggs to spray applications has not been robustly evaluated on substrate materials representative of the most frequently utilized artificial container habitats. Experiments were performed under controlled and natural conditions by applying dilutions of household bleach (52.5 ppt NaOCl) as a spray to eggs on plastic, rubber, and concrete surfaces, with and without a smectite clay thickener. Laboratory assays identified the minimum NaOCl concentrations required to eliminate eggs on plastic (10 ppt), rubber (20 ppt) and concrete (20 ppt) surfaces. Addition of smectite clay reduced the minimum effective concentration to 10 ppt NaOCl for all 3 substrates. A minimum exposure period of 24 h was required to completely eliminate egg viability on concrete surfaces, even at the highest NaOCl concentration (52.5 ppt). Field experiments verified that spray application of a 1∶3 dilution of household bleach mixed with smectite clay can reduce egg hatching by ≥ 99% in shaded and sun-exposed plastic containers. Similarly, 4∶1 dilution of household bleach (with or without smectite clay) eliminated ≥ 98% of eggs from concrete surfaces in outdoor, water-filled drums. In this study, we propose a practical, effective and safe strategy for using household bleach to eliminate Ae. aegypti eggs in a range of artificial container habitats.

  12. Coexistence of Philodina roseola (Rotifera: Bdelloidea) with larvae of Aedes aegypti in India.

    PubMed

    Muniaraj, M; Sathish Babu, R

    2014-06-01

    The vector mosquitoes, Aedes aegypti and Aedes albopictus of dengue and Chikungunya fever are closely associated with human habitations and adapted to feed on human blood. They undergo larval and pupal development in natural and artificial freshwater collections in the urban and peri-urban environment. Although reports are available about the feeding behaviour of the thriving mosquito larvae, much information is still required to understand the successful survival of Aedes mosquitoes in small and temporary water collections. This study was undertaken to determine the co-existence and prevalence of Philodina roseola and other Bdelloid rotifers in the container habitats of Ae. aegypti mosquitoes. The investigation was conducted in 43 villages which belong to four districts in South India, affected by the epidemic of either dengue or Chikungunya fever. A total of 2093 houses and 12980 containers were examined for Aedes breeding and those containers with Aedes larvae were chosen for further investigation. The investigation showed that, the P. roseola was found associated in 502 (98.2%) containers, P. roseola along with other Philodina sp. in 126 containers (25%) and P. roseola along with other Philodina sp. and other Bdelloid rotifers found in 93 containers (19%). Since the members of the genus Philodina can survive desiccation, reproduce by parthenogenesis, can be transported by wind easily and more importantly, it can incorporate the genome of other organisms including viruses, understanding the co-existence and relationship of Philodina sp. with Aedes larvae would be helpful in the control of Aedes breeding and the control measures can be designed keeping the association of Bdelloids with Aedes in mind.

  13. Larvicidal, ovicidal, and adulticidal efficacy of Erythrina indica (Lam.) (Family: Fabaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-02-01

    Mosquitoes are the major vector for the transmission of malaria, dengue fever, yellow fever, filariasis, schistosomiasis, and Japanese encephalitis. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal, ovicidal, and adulticidal potential of the crude hexane, benzene, chloroform, ethyl acetate, and methanol solvent extracts from the medicinal plant Erythrina indica against the medically important mosquito vectors, Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of leaf of E. indica against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus with the LC50 and LC90 values of 69.43, 75.13, and 91.41 ppm and 125.49, 134.31, and 167.14 ppm, respectively. The mean percent hatchability of the eggs was observed after 48 h post treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of E. indica against A. stephensi, A. aegypti, and C. quinquefasciatus exerted 100 % mortality (zero hatchability) at 150, 200, and 250 ppm, respectively. Control eggs showed above 99.3-100 % hatchability. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and

  14. Larvicidal, Repellent, and Irritant Potential of the Seed-Derived Essential oil of Apium graveolens Against Dengue Vector, Aedes aegypti L. (Diptera: Culicidae).

    PubMed

    Kumar, Sarita; Mishra, Monika; Wahab, Naim; Warikoo, Radhika

    2014-01-01

    Aedes aegypti L. is one of the primary disease vectors spreading various dreadful diseases throughout the world, specifically over tropics and subtropics. Keeping in view the adverse effects of chemical insecticides-based intervention measures, the eco-friendly and bio-degradable essential oil extracted from the seeds of celery, Apium graveolens were investigated for its efficacy against Ae. aegypti. Larvicidal bioassay carried out with the seed oil against early fourth instars of Ae. aegypti caused an LC50 and LC90 values of 16.10 and 29.08 ppm, respectively, after an exposure to 24 h. The cidal effect of the celery seed oil augmented by 1.2-fold; after an exposure to 48 h; revealing an LC50 value of 13.22 ppm. Interestingly, the seed oil did not cause immediate larval mortality, suggesting a delayed toxicity against the larval stage. Present investigations also revealed remarkable effective repellency of the oil leading to 100% protection till 165 min as compared to control that did not result in any repellency against adult Ae. aegypti. Interestingly, only one bite was recorded in the 165th-min after which only two bites were scored until 180 min of exposure of the adult mosquitoes to the oil. An exciting observation was that the knocked-down effect in adults exposed to 10% oil-impregnated papers. The contact irritancy assays with paper impregnated with 1% celery seed oil caused first flight only after 4 s resulting in an average of 63.66 flights during 15 min of exposure revealing the relative irritability of 26.97. The qualitative phytochemical analysis of the seed oil showed the presence of flavonoids, lactones, and terpenoids as the major constituents suggesting their probable role in the toxicity. Our results confirmed that celery seed essential oil can be used as an efficient larvicide and repellent against Ae. aegypti. The identification of the bioactive components, their mode of action, and studying effects on non-target organisms and the

  15. Larvicidal, Repellent, and Irritant Potential of the Seed-Derived Essential oil of Apium graveolens Against Dengue Vector, Aedes aegypti L. (Diptera: Culicidae)

    PubMed Central

    Kumar, Sarita; Mishra, Monika; Wahab, Naim; Warikoo, Radhika

    2014-01-01

    Aedes aegypti L. is one of the primary disease vectors spreading various dreadful diseases throughout the world, specifically over tropics and subtropics. Keeping in view the adverse effects of chemical insecticides-based intervention measures, the eco-friendly and bio-degradable essential oil extracted from the seeds of celery, Apium graveolens were investigated for its efficacy against Ae. aegypti. Larvicidal bioassay carried out with the seed oil against early fourth instars of Ae. aegypti caused an LC50 and LC90 values of 16.10 and 29.08 ppm, respectively, after an exposure to 24 h. The cidal effect of the celery seed oil augmented by 1.2-fold; after an exposure to 48 h; revealing an LC50 value of 13.22 ppm. Interestingly, the seed oil did not cause immediate larval mortality, suggesting a delayed toxicity against the larval stage. Present investigations also revealed remarkable effective repellency of the oil leading to 100% protection till 165 min as compared to control that did not result in any repellency against adult Ae. aegypti. Interestingly, only one bite was recorded in the 165th-min after which only two bites were scored until 180 min of exposure of the adult mosquitoes to the oil. An exciting observation was that the knocked-down effect in adults exposed to 10% oil-impregnated papers. The contact irritancy assays with paper impregnated with 1% celery seed oil caused first flight only after 4 s resulting in an average of 63.66 flights during 15 min of exposure revealing the relative irritability of 26.97. The qualitative phytochemical analysis of the seed oil showed the presence of flavonoids, lactones, and terpenoids as the major constituents suggesting their probable role in the toxicity. Our results confirmed that celery seed essential oil can be used as an efficient larvicide and repellent against Ae. aegypti. The identification of the bioactive components, their mode of action, and studying effects on non-target organisms and the

  16. A new ovitrap made of slow release natural materials containing pyriproxyfen for Aedes aegypti (Diptera:Culicidae) control.

    PubMed

    Juan, Laura; Seccacini, Emilia; Zerba, Eduardo; Licastro, Susana

    2013-07-01

    ABSTRACT This initial study is aimed to measure the performance of incorporating pyriproxyfen in natural materials with low environmental impact to obtain slow release formulations that can be used as larvicidal or autocidal ovitraps avoiding hatched Aedes aegypti (L.) eggs to emerge as adults. Hollow candles made of beeswax or paraffin:stearin 1:1 mixture containing pyriproxyfen 0.01 and 0.05% were prepared and used as holding water containers for larval bioassay. Pyriproxyfen was released quickly into the larvae-breeding water. Ae. aegypti larvae were introduced immediately after the addition of tap water to the hollow candles (t = 1 min) or after 1, 4, and 8 h. More than 40% of the larvae did not emerge as adults for t = 1 min, reaching 80-100% when the larvae were added after 1 or 4 h, respectively. The hollow candles were kept at room temperature, and water was replaced every 15 d. Bioassays performed every 30 d showed that the residual activity obtained for both matrices and both concentrations of pyriproxyfen was higher than 360 d, with 100% inhibition of adult emergence. PMID:23926792

  17. The component of Carica papaya seed toxic to A. aegypti and the identification of tegupain, the enzyme that generates it.

    PubMed

    Nunes, Natalia N dos S; Santana, Lucimeire A; Sampaio, Misako U; Lemos, Francisco J A; Oliva, Maria Luiza

    2013-07-01

    As Aedes aegypti transmits the etiologic agents of both yellow and dengue fever; vector control is considered essential to minimise their incidence. The aim of this work was to identify the component of Carica papaya seed toxic to A. aegypti, and the identification of tegupain, the enzyme that generates it. Aqueous extracts (1%, w/v) of the seed tegument and cotyledon of C. papaya are not larvicidal isolately. However, a mixture of 17μgmL(-1) tegument extract and 27μgmL(-1) cotyledon extract caused 100% larval mortality in a bioassay. The mixture was no longer larvicidal after the tegument extract was pre-treated at 100°C for 10min. The enzyme tegupain efficiently hydrolysed the substrate Z-Phe-Arg-pNan (Km 58.8μM, Kcat 28020s(-1), Kcat/Km 5×10(8)M(-1) s(-1)), and its activity increased with 2mM dithiothreitol (DTT), at 37°C, pH 5.0. The chelating agent EDTA did not modify the enzyme activity. Inhibition of tegupain by cystatin (Kiapp 2.43nM), E64 (3.64nM, 83% inhibition), and the propeptide N-terminal sequence indicate that the toxic activity is due to a novel cysteine proteinase-like enzyme, rendered active upon the hydrolysis of a cotyledon component of C. papaya seeds.

  18. Oviposition Behavior in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Response to the Presence of Heterospecific and Conspecific Larvae.

    PubMed

    Gonzalez, Paula V; González Audino, Paola A; Masuh, Héctor M

    2016-03-01

    In mosquitoes, location of suitable sites for oviposition requires a set of visual, tactile, and olfactory cues that influences females before laying their eggs. The ability of gravid females to distinguish among potential oviposition sites that will or will not support the growth, development, and survival of their progeny is critical. Aedes aegypti (L.) and Aedes albopictus (Skuse) share ecological niches, being highly competitive in larval stage. We studied the oviposition behavior of both species in the presence of larvae of one or the other species (heterospecific or conspecific larvae). The number of eggs laid by gravid females on oviposition sites (water with different or the same species of Aedes larvae) were compared. The presence and density of heterospecific or conspecific larvae had a positive or negative effect on the ovipositional responses, measured as an oviposition activity index. For both species, the oviposition was not affected by heterospecific larvae with densities between 10 and 100 larvae in water, but a strong attractant behavior was observed for a density of 500 larvae in water. For Ae. albopictus in the presence of larvae of the same species (conspecific oviposition), we observed an attractant effect for larvae density of 10 but not for 100 or 500 larvae in water. Instead, for Ae. aegypti, we observed attraction only for 100 larvae, not for 10 or 500 larvae. Results presented here provide an additional insight about oviposition behavior responses of gravid females in the presence of conspecific and heterospecific larvae in breeding sites. PMID:26634825

  19. Temephos resistance and esterase activity in the mosquito Aedes aegypti in Havana, Cuba increased dramatically between 2006 and 2008.

    PubMed

    Bisset, J A; Rodríguez, M M; Ricardo, Y; Ranson, H; Pérez, O; Moya, M; Vázquez, A

    2011-09-01

    Aedes aegypti (L.) (Diptera: Culicidae) control programmes in Cuba rely on the application of the organophosphate temephos for larval control. Hence, the monitoring of resistance to this insecticide is an essential component of such programmes. Here, 15 field populations from different municipalities of Havana City were assayed for resistance to temephos. High levels of resistance were detected in all strains and resistance ratios were highly correlated with esterase activity (P = 0.00001). Populations from three municipalities were tested in both 2006 and 2008; resistance and esterase activities both significantly increased during this 2-year period. Synergist studies demonstrated that neither glutathione transferases nor monooxygenases were associated with the increase in resistance to temephos in this period. The duration of the efficacy of commercial formulations of temephos in controlling Ae. aegypti populations in Havana City was reduced by the high level of temephos resistance observed; hence these data are of clear operational significance for the dengue control programme in Cuba. New integrated strategies to avoid further increases in temephos resistance in Cuba are necessary.

  20. Aedes aegypti D7 Saliva Protein Inhibits Dengue Virus Infection

    PubMed Central

    Conway, Michael J.; Londono-Renteria, Berlin; Troupin, Andrea; Watson, Alan M.; Klimstra, William B.; Fikrig, Erol; Colpitts, Tonya M.

    2016-01-01

    Aedes aegypti is the primary vector of several medically relevant arboviruses including dengue virus (DENV) types 1–4. Ae. aegypti transmits DENV by inoculating virus-infected saliva into host skin during probing and feeding. Ae. aegypti saliva contains over one hundred unique proteins and these proteins have diverse functions, including facilitating blood feeding. Previously, we showed that Ae. aegypti salivary gland extracts (SGEs) enhanced dissemination of DENV to draining lymph nodes. In contrast, HPLC-fractionation revealed that some SGE components inhibited infection. Here, we show that D7 proteins are enriched in HPLC fractions that are inhibitory to DENV infection, and that recombinant D7 protein can inhibit DENV infection in vitro and in vivo. Further, binding assays indicate that D7 protein can directly interact with DENV virions and recombinant DENV envelope protein. These data reveal a novel role for D7 proteins, which inhibits arbovirus transmission to vertebrates through a direct interaction with virions. PMID:27632170

  1. Microinjection of A. aegypti embryos to obtain transgenic mosquitoes.

    PubMed

    Jasinskiene, Nijole; Juhn, Jennifer; James, Anthony A

    2007-01-01

    In this video, Nijole Jasinskiene demonstrates the methodology employed to generate transgenic Aedes aegypti mosquitoes, which are vectors for dengue fever. The techniques for correctly preparing microinjection needles, desiccating embryos, and performing microinjection are demonstrated.

  2. Aedes aegypti D7 Saliva Protein Inhibits Dengue Virus Infection.

    PubMed

    Conway, Michael J; Londono-Renteria, Berlin; Troupin, Andrea; Watson, Alan M; Klimstra, William B; Fikrig, Erol; Colpitts, Tonya M

    2016-09-01

    Aedes aegypti is the primary vector of several medically relevant arboviruses including dengue virus (DENV) types 1-4. Ae. aegypti transmits DENV by inoculating virus-infected saliva into host skin during probing and feeding. Ae. aegypti saliva contains over one hundred unique proteins and these proteins have diverse functions, including facilitating blood feeding. Previously, we showed that Ae. aegypti salivary gland extracts (SGEs) enhanced dissemination of DENV to draining lymph nodes. In contrast, HPLC-fractionation revealed that some SGE components inhibited infection. Here, we show that D7 proteins are enriched in HPLC fractions that are inhibitory to DENV infection, and that recombinant D7 protein can inhibit DENV infection in vitro and in vivo. Further, binding assays indicate that D7 protein can directly interact with DENV virions and recombinant DENV envelope protein. These data reveal a novel role for D7 proteins, which inhibits arbovirus transmission to vertebrates through a direct interaction with virions. PMID:27632170

  3. Detection of Chikungunya virus in Aedes aegypti during 2011 outbreak in Al Hodayda, Yemen.

    PubMed

    Zayed, Alia; Awash, Abdullah A; Esmail, Mohammed A; Al-Mohamadi, Hani A; Al-Salwai, Mostafa; Al-Jasari, Adel; Medhat, Iman; Morales-Betoulle, Maria E; Mnzava, Abraham

    2012-07-01

    In October 2010, the Ministry of Public Health and Population reported an outbreak of dengue-like acute febrile illness in Al Hodayda governorate. By January 2011, a total of 1542 cases had been recorded from 19 of the 26 districts in the governorate with 104 purportedly associated deaths. In response this event, in January 2011 entomological investigations aimed at identifying the primary vector and the epidemic associated etiological agent were carried out. Based on the reported cases and the progress of the outbreak in the governorate, mosquito collection was undertaken in two of the most recent outbreak areas; Al Khokha district (130km south of Al Hodayda) and Al Muneera district (100km north). Mosquito adults were collected from houses using BG-sentinel™ traps, aspiration of resting mosquitoes and knock-down spraying. Indoor and outdoor containers adjacent to the houses were inspected for larvae. Subsequently mosquito pools were analyzed by RT-PCR for detection of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, DENV-4), and for Chikungunya virus (CHIKV). Aedes aegypti was the dominant mosquito species collected. Four pools represent 40% of the tested pools, all containing adult female Ae. aegypti, were positive for CHIKV. Three CHIKV isolates were obtained from the RNA positive mosquito pools and identified by rRT-PCR. This finding marks the first record of CHIKV isolated from Ae. aegypti in Yemen. The larval container and Breteau indices in the visited localities surveyed were estimated at 53.8 and 100, respectively. The emergence of this unprecedented CHIKV epidemic in Al Hodayda is adding up another arboviral burden to the already existing vector-borne diseases. Considering the governorate as one focal port in the Red Sea region, the spread of the disease to other areas in Yemen and in neighboring countries is anticipated. Public health education and simple measures to detect and prevent mosquito breeding in water storage containers could prevent

  4. Insect midgut carboxypeptidases with emphasis on S10 hemipteran and M14 lepidopteran carboxypeptidases.

    PubMed

    Ferreira, C; Rebola, K G O; Cardoso, C; Bragatto, I; Ribeiro, A F; Terra, W R

    2015-04-01

    We compared the whole complement of midgut carboxypeptidases from 10 insects pertaining to five orders based on transcriptomes obtained by deep sequencing and biochemical data. Most of the carboxypeptidases were metallocarboxypeptidases from family M14, with carboxypeptidase A (CPA) predominating over carboxypeptidase B (CPB). They were found in all of the insects studied except for the hemipterans and a bruchid beetle. M14 carboxypeptidases were expressed only in the midgut of Spodoptera frugiperda (Lepidoptera). The most expressed CPA from this insect (SfCPA) was cloned, sequenced and expressed as a recombinant enzyme. This enzyme was used to generate antibodies used to demonstrate that SfCPA is secreted by an exocytic route. Serine carboxypeptidases from family S10 were found in all of the insects studied here. In S. frugiperda, they are expressed in all tissues besides the midgut, in accordance with their presumed lysosomal role. In the hemipteran Dysdercus peruvianus, S10 carboxypeptidases are expressed only in midgut, suggesting that they are digestive enzymes. This was confirmed by enzyme assays of midgut contents. Furthermore, the substrate specificity of D. peruvianus S10 carboxypeptidases are predicted to be one CPC (preferring hydrophobic residues) and one CPD (preferring basic residues), thus able to hydrolyse the peptides formed by their digestive cathepsin D and cathepsin L, respectively. The role of S10 carboxypeptidases in bruchid beetles are suggested to be the same as in hemipterans.

  5. Proteome analysis of Cry4Ba toxin-interacting Aedes aegypti lipid rafts using geLC-MS/MS.

    PubMed

    Bayyareddy, Krishnareddy; Zhu, Xiang; Orlando, Ron; Adang, Michael J

    2012-12-01

    Lipid rafts are microdomains in the plasma membrane of eukaryotic cells. Among their many functions, lipid rafts are involved in cell toxicity caused by pore forming bacterial toxins including Bacillus thuringiensis (Bt) Cry toxins. We isolated lipid rafts from brush border membrane vesicles (BBMV) of Aedes aegypti larvae as a detergent resistant membrane (DRM) fraction on density gradients. Cholesterol, aminopeptidase (APN), alkaline phosphatase (ALP) and the raft marker flotillin were preferentially partitioned into the lipid raft fraction. When mosquitocidal Cry4Ba toxin was preincubated with BBMV, Cry4Ba localized to lipid rafts. A proteomic approach based on one-dimensional gel electrophoresis, in-gel trypsin digestion, followed by liquid chromatography-mass spectrometry (geLC-MS/MS) identified a total of 386 proteins. Of which many are typical lipid raft marker proteins including flotillins and glycosylphosphatidylinositol (GPI)-anchored proteins. Identified raft proteins were annotated in silico for functional and physicochemical characteristics. Parameters such as distribution of isoelectric point, molecular mass, and predicted post-translational modifications relevant to lipid raft proteins (GPI anchorage and myristoylation or palmitoylation) were analyzed for identified proteins in the DRM fraction. From a functional point of view, this study identified proteins implicated in Cry toxin interactions as well as membrane-associated proteins expressed in the mosquito midgut that have potential relevance to mosquito biology and vector management.

  6. Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression

    PubMed Central

    Popham, Holly J. R.; Gould, Fred; Adang, Michael J.; Jurat-Fuentes, Juan Luis

    2015-01-01

    Heliothine pests such as the tobacco budworm, Heliothis virescens (F.), pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generation from this species for which lacks a sequenced genome. In order to amass a de novo transcriptome for this moth, transcript sequences generated from Illumina, Roche 454, and Sanger sequencing platforms were merged into a single de novo transcriptome assembly. This pooling strategy allowed a thorough sampling of transcripts produced under diverse environmental conditions, developmental stages, tissues, and infections with entomopathogens used for biological control, to provide the most complete transcriptome to date for this species. Over 138 million reads from the three platforms were assembled into the final set of 63,648 contigs. Of these, 29,978 had significant BLAST scores indicating orthologous relationships to transcripts of other insect species, with the top-hit species being the monarch butterfly (Danaus plexippus) and silkworm (Bombyx mori). Among identified H. virescens orthologs were immune effectors, signal transduction pathways, olfactory receptors, hormone biosynthetic pathways, peptide hormones and their receptors, digestive enzymes, and insecticide resistance enzymes. As an example, we demonstrate the utility of this transcriptomic resource to study gene expression profiling of larval midguts and detect transcripts of putative Bacillus thuringiensis (Bt) Cry toxin receptors. The substantial molecular resources described in this study will facilitate development of H. virescens as a relevant biological model for functional genomics and for new biological

  7. Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression.

    PubMed

    Perera, Omaththage P; Shelby, Kent S; Popham, Holly J R; Gould, Fred; Adang, Michael J; Jurat-Fuentes, Juan Luis

    2015-01-01

    Heliothine pests such as the tobacco budworm, Heliothis virescens (F.), pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generation from this species for which lacks a sequenced genome. In order to amass a de novo transcriptome for this moth, transcript sequences generated from Illumina, Roche 454, and Sanger sequencing platforms were merged into a single de novo transcriptome assembly. This pooling strategy allowed a thorough sampling of transcripts produced under diverse environmental conditions, developmental stages, tissues, and infections with entomopathogens used for biological control, to provide the most complete transcriptome to date for this species. Over 138 million reads from the three platforms were assembled into the final set of 63,648 contigs. Of these, 29,978 had significant BLAST scores indicating orthologous relationships to transcripts of other insect species, with the top-hit species being the monarch butterfly (Danaus plexippus) and silkworm (Bombyx mori). Among identified H. virescens orthologs were immune effectors, signal transduction pathways, olfactory receptors, hormone biosynthetic pathways, peptide hormones and their receptors, digestive enzymes, and insecticide resistance enzymes. As an example, we demonstrate the utility of this transcriptomic resource to study gene expression profiling of larval midguts and detect transcripts of putative Bacillus thuringiensis (Bt) Cry toxin receptors. The substantial molecular resources described in this study will facilitate development of H. virescens as a relevant biological model for functional genomics and for new biological

  8. Physiological and biochemical effects of botanical extract from Piper nigrum Linn (Piperaceae) against the dengue vector Aedes aegypti Liston (Diptera: Culicidae).

    PubMed

    Lija-Escaline, Jalasteen; Senthil-Nathan, Sengottayan; Thanigaivel, Annamalai; Pradeepa, Venkatraman; Vasantha-Srinivasan, Prabhakaran; Ponsankar, Athirstam; Edwin, Edward Sam; Selin-Rani, Selvaraj; Abdel-Megeed, Ahmed

    2015-11-01

    The leaves of Piper nigrum L. (Piperaceae) were evaluated for chemical constituents and mosquito larvicidal activity against the larvae of Aedes aegypti. GC and GC-MS analyses revealed that the crude extracts contain 16 compounds. Thymol (20.77%) and ç-elemene (10.42%) were identified as the major constituents followed by cyclohexene, 4-ethenyl-4-methyl-3-(1-methylethenyl)-1-(1 methylethyl)-, (3R-trans) (7.58%), 4,6-octadienoic acid, 2-acetyl-2-methyl-, ethyl ester (6.98), 2(3H)-furanone, 3,4-bis(1,3-benzodioxol-5-ylmethyl) dihydro-, (3R-trans) (6.95%), 1-naphthalenol, 1,2,3,4,4a,7,8,8a-octahydro-1,6-dimethyl-4-(1-methylethyl)-, [1R-(1à,4á,4aá,8aá)]-(Cedreanol) (5.30%), trans-2-undecen-1-ol (4.48%), phytol (4.22%), 1,6-cyclodecadiene, 1-methyl-5-methylene-8-(1-methylethyl)-,[s-(E,E)] (3.78%) and 2,6-dimethyl-3,5,7-octatriene-2-ol, Z,Z (2.39%). Larval mortality was observed after 3 h of exposure period. The crude extract showed remarkable larvicidal activity against Ae. aegypti (LC50 = 34.97). The larvae of Ae. aegypti exposed to the P. nigrum, significantly reduced the activities of α- and β-carboxylesterases and superdioxide. Further, P. nigrum extract was severely affecting the mosquito gut cellular organelles. Based on the results, the chemical constituents of crude extracts of P. nigrum can be considered as a new source of larvicide for the control of Ae. aegypti.

  9. Physiological and biochemical effects of botanical extract from Piper nigrum Linn (Piperaceae) against the dengue vector Aedes aegypti Liston (Diptera: Culicidae).

    PubMed

    Lija-Escaline, Jalasteen; Senthil-Nathan, Sengottayan; Thanigaivel, Annamalai; Pradeepa, Venkatraman; Vasantha-Srinivasan, Prabhakaran; Ponsankar, Athirstam; Edwin, Edward Sam; Selin-Rani, Selvaraj; Abdel-Megeed, Ahmed

    2015-11-01

    The leaves of Piper nigrum L. (Piperaceae) were evaluated for chemical constituents and mosquito larvicidal activity against the larvae of Aedes aegypti. GC and GC-MS analyses revealed that the crude extracts contain 16 compounds. Thymol (20.77%) and ç-elemene (10.42%) were identified as the major constituents followed by cyclohexene, 4-ethenyl-4-methyl-3-(1-methylethenyl)-1-(1 methylethyl)-, (3R-trans) (7.58%), 4,6-octadienoic acid, 2-acetyl-2-methyl-, ethyl ester (6.98), 2(3H)-furanone, 3,4-bis(1,3-benzodioxol-5-ylmethyl) dihydro-, (3R-trans) (6.95%), 1-naphthalenol, 1,2,3,4,4a,7,8,8a-octahydro-1,6-dimethyl-4-(1-methylethyl)-, [1R-(1à,4á,4aá,8aá)]-(Cedreanol) (5.30%), trans-2-undecen-1-ol (4.48%), phytol (4.22%), 1,6-cyclodecadiene, 1-methyl-5-methylene-8-(1-methylethyl)-,[s-(E,E)] (3.78%) and 2,6-dimethyl-3,5,7-octatriene-2-ol, Z,Z (2.39%). Larval mortality was observed after 3 h of exposure period. The crude extract showed remarkable larvicidal activity against Ae. aegypti (LC50 = 34.97). The larvae of Ae. aegypti exposed to the P. nigrum, significantly reduced the activities of α- and β-carboxylesterases and superdioxide. Further, P. nigrum extract was severely affecting the mosquito gut cellular organelles. Based on the results, the chemical constituents of crude extracts of P. nigrum can be considered as a new source of larvicide for the control of Ae. aegypti. PMID:26277727

  10. Temporal Dynamics and Spatial Patterns of Aedes aegypti Breeding Sites, in the Context of a Dengue Control Program in Tartagal (Salta Province, Argentina)

    PubMed Central

    Espinosa, Manuel; Weinberg, Diego; Rotela, Camilo H.; Polop, Francisco; Abril, Marcelo; Scavuzzo, Carlos Marcelo

    2016-01-01

    Background Since 2009, Fundación Mundo Sano has implemented an Aedes aegypti Surveillance and Control Program in Tartagal city (Salta Province, Argentina). The purpose of this study was to analyze temporal dynamics of Ae. aegypti breeding sites spatial distribution, during five years of samplings, and the effect of control actions over vector population dynamics. Methodology/Principal Findings Seasonal entomological (larval) samplings were conducted in 17,815 fixed sites in Tartagal urban area between 2009 and 2014. Based on information of breeding sites abundance, from satellite remote sensing data (RS), and by the use of Geographic Information Systems (GIS), spatial analysis (hotspots and cluster analysis) and predictive model (MaxEnt) were performed. Spatial analysis showed a distribution pattern with the highest breeding densities registered in city outskirts. The model indicated that 75% of Ae. aegypti distribution is explained by 3 variables: bare soil coverage percentage (44.9%), urbanization coverage percentage(13.5%) and water distribution (11.6%). Conclusions/Significance This results have called attention to the way entomological field data and information from geospatial origin (RS/GIS) are used to infer scenarios which could then be applied in epidemiological surveillance programs and in the determination of dengue control strategies. Predictive maps development constructed with Ae. aegypti systematic spatiotemporal data, in Tartagal city, would allow public health workers to identify and target high-risk areas with appropriate and timely control measures. These tools could help decision-makers to improve health system responses and preventive measures related to vector control. PMID:27223693

  11. Diversity of aminopeptidases, derived from four lepidopteran gene duplications, and polycalins expressed in the midgut of Helicoverpa armigera: Identification of proteins binding the δ-endotoxin, Cry1Ac of Bacillus thuringiensis

    PubMed Central

    Angelucci, Constanza; Barrett-Wilt, Gregory A.; Hunt, Donald F.; Akhurst, Raymond J.; East, Peter D.; Gordon, Karl H.J.; Campbell, Peter M.

    2010-01-01

    Helicoverpa armigera midgut proteins that bind the Bacillus thuringiensis (Bt) δ-endotoxin Cry1Ac were purified by affinity chromatography. SDS-PAGE showed that several proteins were eluted with N-acetylgalactosamine and no further proteins were detected after elution with urea. Tandem mass spectral data for tryptic peptides initially indicated that the proteins resembled aminopeptidases (APNs) from other lepidopterans and cDNA sequences for seven APNs were isolated from H. armigera through a combination of cloning with primers derived from predicted peptide sequences and established EST libraries. Phylogenetic analysis showed lepidopteran APN genes in nine clades of which five were part of a lepidopteran-specific radiation. The Cry1Ac-binding proteins were then identified with four of the seven HaAPN genes. Three of those four APNs are likely orthologs of APNs characterised as Cry1Ac-binding proteins in other lepidopterans. The fourth Cry1Ac-binding APN has orthologs not previously identified as Cry1Ac-binding partners. The HaAPN genes were expressed predominantly in the midgut through larval development. Each showed consistent expression along the length of the midgut but five of the genes were expressed at levels about two orders of magnitude greater than the remaining two. The remaining mass spectral data identified sequences encoding polycalin proteins with multiple lipocalin-like domains. A polycalin has only been previously reported in another lepidopteran, Bombyx mori, but polycalins in both species are now linked with binding of Bt Cry toxins. This is the first report of hybrid, lipocalin-like domains in shorter polycalin sequences that are not present in the longest sequence. We propose that these hybrid domains are generated by alternative splicing of the mRNA. PMID:18549954

  12. Lessons of Aedes aegypti control in Thailand.

    PubMed

    Gratz, N G

    1993-01-01

    The incidence of dengue haemorrhagic fever (DHF) in Thailand has increased cyclically since the first recognized outbreak in 1958. Without an effective vaccine against dengue, and considering the clinical difficulty of treating DHF cases, vector control is needed to prevent dengue transmission. Since the establishment of the WHO Aedes Research Unit in 1964, continued since 1973 as the WHO Collaborating Centre at the Department of Medical Research in Bangkok, much operational research has been carried out in Thailand on the bionomics and control of dengue vectors: Aedes aegypti and Ae. albopictus. This review shows that, as in most other countries, dengue vector control programmes in Thailand make little use of the procedures arising from research, nor have they reduced the upward trend of dengue or prevented DHF outbreaks. Implications of the reluctance to use results of operational research on vector control are considered and remedial suggestions made.

  13. Maintenance of midgut epithelial cells from Dendroctonus valens (Coleoptera: Scolytidae) in vitro.

    PubMed

    Sánchez, L; Andrade, J L; Cisneros, R; Zúñiga, G

    2004-01-01

    This article describes the culture of epithelial cells from anterior and posterior midgut regions of adult Dendroctonus valens. Culture conditions were established, and cell adherence was improved by means of a new technique that allowed the cells to grow between two glass coverslips. Cytoplasmic projections occur as anterior midgut cells grow to confluence; these projections were not observed in cells of the posterior midgut. The optimal culture medium for the maintenance of these epithelial cells was Roswell Park Memorial Institute 1640 medium at 25 degrees C. Cells in Grace's medium died in 24 h. Cultures did not require CO(2) atmosphere, but culture development was favored by the microaerophilic environment and the dark conditions in which the cells were grown, between the coverslips.

  14. EGFR/Ras/MAPK signaling mediates adult midgut epithelial homeostasis and regeneration in Drosophila

    PubMed Central

    Jiang, Huaqi; Grenley, Marc O.; Bravo, Maria-Jose; Blumhagen, Rachel Z.; Edgar, Bruce A.

    2010-01-01

    Many tissues in higher animals undergo dynamic homeostatic growth, wherein damaged or aged cells are replaced by the progeny of resident stem cells. To maintain homeostasis, stem cells must respond to tissue needs. Here we show that in response to damage or stress in the intestinal (midgut) epithelium of adult Drosophila, multiple EGFR ligands and rhomboids (intramembrane proteases that activate some EGFR ligands) are induced, leading to the activation of EGFR signaling in intestinal stem cells (ISCs). Activation of EGFR signaling promotes ISC division and midgut epithelium regeneration, thus maintaining tissue homeostasis. ISCs defective in EGFR signaling cannot grow or divide, are poorly maintained, and cannot support midgut epithelium regeneration following enteric infection by the bacterium, Pseudomonas entomophila. Furthermore, ISC proliferation induced by Jak/Stat signaling is dependent upon EGFR signaling. Thus the EGFR/Ras/MAPK signaling pathway plays central, essential roles in ISC maintenance and the feedback system that mediates intestinal homeostasis. PMID:21167805

  15. [Oral receptivity of Aedes aegypti formosus from Franceville (Gabon, central Africa) for type 2 dengue virus].

    PubMed

    Vazeille-Falcoz, M; Failloux, A B; Mousson, L; Elissa, N; Rodhain, F

    1999-12-01

    Dengue is widely distributed in the tropics but epidemic activity was rarely reported in Africa before the 1980's. In the past 15 years, increased epidemic dengue fever has been reported both in East and West Africa, raising concern about the ability of local populations of Aedes aegypti to transmit dengue viruses. Ae. aegypti is present in two forms in Africa: Ae. aegypti aegypti and Ae. aegypti formosus. This latter form, much darker, was not originally a local species but is now colonizing artificial breeding sites within cities. We have been able to demonstrate the oral susceptibility for dengue type 2 virus of Ae. aegypti formosus collected in Franceville, Gabon (Central Africa). However, these mosquitoes sampled exhibited lower infection rates than those of a control colony of Ae. aegypti aegypti originating from French Polynesia.

  16. Identification of Essential Containers for Aedes Larval Breeding to Control Dengue in Dhaka, Bangladesh

    PubMed Central

    Ferdousi, Farhana; Yoshimatsu, Shoji; Ma, Enbo; Sohel, Nazmul; Wagatsuma, Yukiko

    2015-01-01

    Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes Aedes aegypti and Aedes albopictus. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for Aedes larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with Aedes larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for Aedes larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with Aedes larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of Aedes larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted. PMID:26865829

  17. Identification of Essential Containers for Aedes Larval Breeding to Control Dengue in Dhaka, Bangladesh.

    PubMed

    Ferdousi, Farhana; Yoshimatsu, Shoji; Ma, Enbo; Sohel, Nazmul; Wagatsuma, Yukiko

    2015-12-01

    Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes Aedes aegypti and Aedes albopictus. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for Aedes larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with Aedes larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for Aedes larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with Aedes larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of Aedes larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted.

  18. Increased centrosome amplification in aged stem cells of the Drosophila midgut

    SciTech Connect

    Park, Joung-Sun; Pyo, Jung-Hoon; Na, Hyun-Jin; Jeon, Ho-Jun; Kim, Young-Shin; Arking, Robert; Yoo, Mi-Ae

    2014-07-25

    Highlights: • Increased centrosome amplification in ISCs of aged Drosophila midguts. • Increased centrosome amplification in ISCs of oxidative stressed Drosophila midguts. • Increased centrosome amplification in ISCs by overexpression of PVR, EGFR, and AKT. • Supernumerary centrosomes can be responsible for abnormal ISC polyploid cells. • Supernumerary centrosomes can be a useful marker for aging stem cells. - Abstract: Age-related changes in long-lived tissue-resident stem cells may be tightly linked to aging and age-related diseases such as cancer. Centrosomes play key roles in cell proliferation, differentiation and migration. Supernumerary centrosomes are known to be an early event in tumorigenesis and senescence. However, the age-related changes of centrosome duplication in tissue-resident stem cells in vivo remain unknown. Here, using anti-γ-tubulin and anti-PH3, we analyzed mitotic intestinal stem cells with supernumerary centrosomes in the adult Drosophila midgut, which may be a versatile model system for stem cell biology. The results showed increased centrosome amplification in intestinal stem cells of aged and oxidatively stressed Drosophila midguts. Increased centrosome amplification was detected by overexpression of PVR, EGFR, and AKT in intestinal stem cells/enteroblasts, known to mimic age-related changes including hyperproliferation of intestinal stem cells and hyperplasia in the midgut. Our data show the first direct evidence for the age-related increase of centrosome amplification in intestinal stem cells and suggest that the Drosophila midgut is an excellent model for studying molecular mechanisms underlying centrosome amplification in aging adult stem cells in vivo.

  19. MicroRNA-regulation of Anopheles gambiae immunity to Plasmodium falciparum infection and midgut microbiota.

    PubMed

    Dennison, Nathan J; BenMarzouk-Hidalgo, Omar J; Dimopoulos, George

    2015-03-01

    Invasion of the malaria vector Anopheles gambiae midgut by Plasmodium parasites triggers transcriptional changes of immune genes that mediate the antiparasitic defense. This response is largely regulated by the Toll and Immune deficiency (IMD) pathways. To determine whether A. gambiae microRNAs (miRNAs) are involved in regulating the anti-Plasmodium defense, we showed that suppression of miRNA biogenesis results in increased resistance to Plasmodium falciparum infection. In silico analysis of A. gambiae immune effector genes identified multiple transcripts with miRNA binding sites. A comparative miRNA microarray abundance analysis of P. falciparum infected and naïve mosquito midgut tissues showed elevated abundance of miRNAs aga-miR-989 and aga-miR-305 in infected midguts. Antagomir inhibition of aga-miR-305 increased resistance to P. falciparum infection and suppressed the midgut microbiota. Conversely, treatment of mosquitoes with an artificial aga-miR-305 mimic increased susceptibility to P. falciparum infection and resulted in expansion of midgut microbiota, suggesting that aga-miR-305 acts as a P. falciparum and gut microbiota agonist by negatively regulating the mosquito immune response. In silico prediction of aga-miR-305 target genes identified several anti-Plasmodium effectors. Our study shows that A. gambiae aga-miR-305 regulates the anti-Plasmodium response and midgut microbiota, likely through post-transcriptional modification of immune effector genes.

  20. The parasitoid, Cotesia flavipes (Cameron) (Hymenoptera: Braconidae), influences food consumption and utilization by larval Diatraea saccharalis (F.) (Lepidoptera: Crambidae).

    PubMed

    Rossi, Guilherme Duarte; Salvador, Gabriela; Cônsoli, Fernando Luis

    2014-10-01

    Parasitoids exploit host insects for food and other resources; they alter host development and physiology to optimize conditions to favor parasitoid development. Parasitoids influence their hosts by injecting eggs, along with a variety of substances, including venoms, polydnaviruses, ovarian fluids, and other maternal factors, into hosts. These factors induce profound changes in hosts, such as behavior, metabolism, endocrine events, and immune defense. Because endoparasitoids develop and consume tissues from within their hosts, it is reasonable to suggest that internal parasitization would also influence host food consumption and metabolism. We report on the effects of parasitism by Cotesia flavipes on the food consumption and utilization of its host, Diatraea saccharalis. Cotesia flavipes reduces the host food consumption, but parasitized larvae considered a unit with their parasitoid's attained the same final weight as the nonparasitized larvae. Nutritional indices, midgut activities of carbohydrases, and trypsin of parasitized and nonparasitized D. saccharalis were assessed. Parasitized larvae had reduced relative food consumption, metabolic and growth rates, coupled with higher efficiency for conversion of the digested, but not ingested, food into body mass. Parasitism also affected food flux through the gut and protein contents in the midgut of parasitized larvae. The activity of α-amylase and trehalase in parasitized host was enhanced in the first day after parasitism relative to control larvae. Saccharase activity remained unchanged during larval development. Trypsin activity was reduced from the fifth to ninth day after parasitism. We argue on the mechanisms involved in host food processing after parasitism.

  1. Larvicidal activity of Morinda citrifolia L. (Noni) (Family: Rubiaceae) leaf extract against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    PubMed

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Shanthakumar, Shanmugam Perumal; Vincent, Savariar; Hwang, Jiang-Shiou

    2012-10-01

    Morinda citrifolia leaf extract was tested for larvicidal activity against three medically important mosquito vectors such as malarial vector Anopheles stephensi, dengue vector Aedes aegypti, and filarial vector Culex quinquefasciatus. The plant material was shade dried at room temperature and powdered coarsely. From the leaf, 1-kg powder was macerated with 3.0 L of hexane, chloroform, acetone, methanol, and water sequentially for a period of 72 h each and filtered. The yield of extracts was hexane (13.56 g), chloroform (15.21 g), acetone (12.85 g), methanol (14.76 g), and water (12.92 g), respectively. The extracts were concentrated at reduced temperature on a rotary vacuum evaporator and stored at a temperature of 4°C. The M. citrifolia leaf extract at 200, 300, 400, 500, and 600 ppm caused a significant mortality of three mosquito species. Hexane, chloroform, acetone, and water caused moderate considerable mortality; however, the highest larval mortality was methanolic extract, observed in three mosquito vectors. The larval mortality was observed after 24-h exposure. No mortality was observed in the control. The third larvae of Anopheles stephensi had values of LC(50) = 345.10, 324.26, 299.97, 261.96, and 284.59 ppm and LC(90) = 653.00, 626.58, 571.89, 505.06, and 549.51 ppm, respectively. The Aedes aegypti had values of LC(50) = 361.75, 343.22, 315.40, 277.92, and 306.98 ppm and LC(90) = 687.39, 659.02, 611.35, 568.18, and 613.25 ppm, respectively. The Culex quinquefasciatus had values of LC(50) = 382.96, 369.85, 344.34, 330.42, and 324.64 ppm and LC(90) = 726.18, 706.57, 669.28, 619.63, and 644.47 ppm, respectively. The results of the leaf extract of M. citrifolia are promising as good larvicidal activity against the mosquito vector Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. This is a new eco-friendly approach for the control of vector control programs. Therefore, this study provides first report on the larvicidal activities against three

  2. Silencing of Anopheles stephensi Heme Peroxidase HPX15 Activates Diverse Immune Pathways to Regulate the Growth of Midgut Bacteria.

    PubMed

    Kajla, Mithilesh; Choudhury, Tania P; Kakani, Parik; Gupta, Kuldeep; Dhawan, Rini; Gupta, Lalita; Kumar, Sanjeev

    2016-01-01

    Anopheles mosquito midgut harbors a diverse group of endogenous bacteria that grow extensively after the blood feeding and help in food digestion and nutrition in many ways. Although, the growth of endogenous bacteria is regulated by various factors, however, the robust antibacterial immune reactions are generally suppressed in this body compartment by a heme peroxidase HPX15 crosslinked mucins barrier. This barrier is formed on the luminal side of the midgut and blocks the direct interactions and recognition of bacteria or their elicitors by the immune reactive midgut epithelium. We hypothesized that in the absence of HPX15, an increased load of exogenous bacteria will enormously induce the mosquito midgut immunity and this situation in turn, can easily regulate mosquito-pathogen interactions. In this study, we found that the blood feeding induced AsHPX15 gene in Anopheles stephensi midgut and promoted the growth of endogenous as well as exogenous fed bacteria. In addition, the mosquito midgut also efficiently regulated the number of these bacteria through the induction of classical Toll and Imd immune pathways. In case of AsHPX15 silenced midguts, the growth of midgut bacteria was largely reduced through the induction of nitric oxide synthase (NOS) gene, a downstream effector molecule of the JAK/STAT pathway. Interestingly, no significant induction of the classical immune pathways was observed in these midguts. Importantly, the NOS is a well known negative regulator of Plasmodium development, thus, we proposed that the induction of diverged immune pathways in the absence of HPX15 mediated midgut barrier might be one of the strategies to manipulate the vectorial capacity of Anopheles mosquito. PMID:27630620

  3. Silencing of Anopheles stephensi Heme Peroxidase HPX15 Activates Diverse Immune Pathways to Regulate the Growth of Midgut Bacteria

    PubMed Central

    Kajla, Mithilesh; Choudhury, Tania P.; Kakani, Parik; Gupta, Kuldeep; Dhawan, Rini; Gupta, Lalita; Kumar, Sanjeev

    2016-01-01

    Anopheles mosquito midgut harbors a diverse group of endogenous bacteria that grow extensively after the blood feeding and help in food digestion and nutrition in many ways. Although, the growth of endogenous bacteria is regulated by various factors, however, the robust antibacterial immune reactions are generally suppressed in this body compartment by a heme peroxidase HPX15 crosslinked mucins barrier. This barrier is formed on the luminal side of the midgut and blocks the direct interactions and recognition of bacteria or their elicitors by the immune reactive midgut epithelium. We hypothesized that in the absence of HPX15, an increased load of exogenous bacteria will enormously induce the mosquito midgut immunity and this situation in turn, can easily regulate mosquito-pathogen interactions. In this study, we found that the blood feeding induced AsHPX15 gene in Anopheles stephensi midgut and promoted the growth of endogenous as well as exogenous fed bacteria. In addition, the mosquito midgut also efficiently regulated the number of these bacteria through the induction of classical Toll and Imd immune pathways. In case of AsHPX15 silenced midguts, the growth of midgut bacteria was largely reduced through the induction of nitric oxide synthase (NOS) gene, a downstream effector molecule of the JAK/STAT pathway. Interestingly, no significant induction of the classical immune pathways was observed in these midguts. Importantly, the NOS is a well known negative regulator of Plasmodium development, thus, we proposed that the induction of diverged immune pathways in the absence of HPX15 mediated midgut barrier might be one of the strategies to manipulate the vectorial capacity of Anopheles mosquito.

  4. Silencing of Anopheles stephensi Heme Peroxidase HPX15 Activates Diverse Immune Pathways to Regulate the Growth of Midgut Bacteria

    PubMed Central

    Kajla, Mithilesh; Choudhury, Tania P.; Kakani, Parik; Gupta, Kuldeep; Dhawan, Rini; Gupta, Lalita; Kumar, Sanjeev

    2016-01-01

    Anopheles mosquito midgut harbors a diverse group of endogenous bacteria that grow extensively after the blood feeding and help in food digestion and nutrition in many ways. Although, the growth of endogenous bacteria is regulated by various factors, however, the robust antibacterial immune reactions are generally suppressed in this body compartment by a heme peroxidase HPX15 crosslinked mucins barrier. This barrier is formed on the luminal side of the midgut and blocks the direct interactions and recognition of bacteria or their elicitors by the immune reactive midgut epithelium. We hypothesized that in the absence of HPX15, an increased load of exogenous bacteria will enormously induce the mosquito midgut immunity and this situation in turn, can easily regulate mosquito-pathogen interactions. In this study, we found that the blood feeding induced AsHPX15 gene in Anopheles stephensi midgut and promoted the growth of endogenous as well as exogenous fed bacteria. In addition, the mosquito midgut also efficiently regulated the number of these bacteria through the induction of classical Toll and Imd immune pathways. In case of AsHPX15 silenced midguts, the growth of midgut bacteria was largely reduced through the induction of nitric oxide synthase (NOS) gene, a downstream effector molecule of the JAK/STAT pathway. Interestingly, no significant induction of the classical immune pathways was observed in these midguts. Importantly, the NOS is a well known negative regulator of Plasmodium development, thus, we proposed that the induction of diverged immune pathways in the absence of HPX15 mediated midgut barrier might be one of the strategies to manipulate the vectorial capacity of Anopheles mosquito. PMID:27630620

  5. The terminology of larval cestodes or metacestodes.

    PubMed

    2002-05-01

    The terminology associated with the nomenclature of larval or metacestodes is reviewed as well as the various morphological and developmental characters used to define different types of larval cestodes. Based on a review of the literature, the key characters differentiating the types of larval cestodes are the presence of a primary lacuna and the invagination/retraction of the scolex. The presence of a cercomer and of a bladder-like enlargement of the larval cestode were considered to be useful secondary characteristics. Using these characters, six basic types of larval cestodes were identified: the procercoid, an alacunate form which cannot develop further until ingested by a second intermediate host; the plerocercus, an alacunate form with a retracted scolex; the plerocercoid, an alacunate form with an everted scolex; the merocercoid, an alacunate form with an invaginated scolex; the cysticercoid, a lacunate form with a retracted scolex; and the cysticercus, a lacunate form with an invaginated scolex. The diversity of larval types within the broad classifications of cysticercoid and cysticercus can be differentiated by the use of appropriate prefixes. Deficiencies in knowledge of specific types of larval cestodes are identified and further avenues of research are indicated.

  6. Dengue-2 virus carrying capacity of Thai Aedes aegypti strains with different susceptibility to deltamethrin.

    PubMed

    Phanpoowong, Theerawit; Lek-Uthai, Usa; Thongrungkiat, Supatra; Komalamisra, Narumon; Srisawat, Raweewan; Russell, Bruce; Renia, Laurent

    2012-05-01

    Deltamethrin-resistant Aedes aegypti currently threatens the effectiveness of dengue hemorrhagic fever control operations in Thailand. Although a previous study has suggested that insecticide resistance may increase Ae. aegypti susceptibility to dengue-2 virus infection, our experimental data showed no significant association between laboratory-induced deltamethrin-resistance in a Thai Ae. aegypti isolate and its susceptibility to dengue -2 infection.

  7. Efficacy of essential oil from Cananga odorata (Lamk.) Hook.f. & Thomson (Annonaceae) against three mosquito species Aedes aegypti (L.), Anopheles dirus (Peyton and Harrison), and Culex quinquefasciatus (Say).

    PubMed

    Soonwera, Mayura

    2015-12-01

    The essential oil of Cananga odorata flowers was evaluated for oviposition-deterrent, ovicidal, insecticidal, and repellent activities toward three mosquito species: Aedes aegypti, Anopheles dirus, and Culex quinquefasciatus. Oviposition deterrence of the oil was evaluated on gravid females using oviposition deterrence bioassay. The results showed that 10 % Ca. odorata exhibited high percent effective repellency against oviposition at 99.4 % to Ae. aegypti, 97.1 % to An. dirus, and 100 % to Cx. quinquefasciatus. Ca. odorata oil was tested for ovicidal activity. Regression equations revealed that the ovicidal rates were positively correlated with the concentrations of the essential oil. As the concentration of essential oil increased from 1, 5, and up to 10 % concentration, the ovicidal rate increased accordingly. Larvicidal activity of the oils was used on immature stages (third and fourth instar lavae and pupae). The maximum larval mortality was found with 10 % Ca. odorata against immature stages, and there were LC50 values ranged from 10.4 to 10.5 % (for Ae. aegypti), <1 % (for An. dirus), and <1 % (for Cx. quinquefasciatus). Adulticidal properties were evaluated with unfed females. Ten percent Ca. odorata oil had high knockdown rates against the three mosquito species at 96 % (for Ae. aegypti), 98.4 % (for An. dirus), and 100 % (for Cx. quinquefasciatus), with EC50 values of 6.2, 4.7, and 5.4 %, respectively. It gave moderate mortality rates after 24 and 48 h of exposure. Ca. odorata oil was assessed for repellency to females by using the modified K&D module. Ten percent Ca. odorata oil gave the strongest value against Ae. aegypti, An. dirus, and Cx. quinquefasciatus, with percentage repellency of 66, 92, and 90 %, respectively. This study demonstrates the potential for the essential oil of Ca. odorata essential oil to be used as a botanical insecticide against three mosquito species.

  8. Efficacy of essential oil from Cananga odorata (Lamk.) Hook.f. & Thomson (Annonaceae) against three mosquito species Aedes aegypti (L.), Anopheles dirus (Peyton and Harrison), and Culex quinquefasciatus (Say).

    PubMed

    Soonwera, Mayura

    2015-12-01

    The essential oil of Cananga odorata flowers was evaluated for oviposition-deterrent, ovicidal, insecticidal, and repellent activities toward three mosquito species: Aedes aegypti, Anopheles dirus, and Culex quinquefasciatus. Oviposition deterrence of the oil was evaluated on gravid females using oviposition deterrence bioassay. The results showed that 10 % Ca. odorata exhibited high percent effective repellency against oviposition at 99.4 % to Ae. aegypti, 97.1 % to An. dirus, and 100 % to Cx. quinquefasciatus. Ca. odorata oil was tested for ovicidal activity. Regression equations revealed that the ovicidal rates were positively correlated with the concentrations of the essential oil. As the concentration of essential oil increased from 1, 5, and up to 10 % concentration, the ovicidal rate increased accordingly. Larvicidal activity of the oils was used on immature stages (third and fourth instar lavae and pupae). The maximum larval mortality was found with 10 % Ca. odorata against immature stages, and there were LC50 values ranged from 10.4 to 10.5 % (for Ae. aegypti), <1 % (for An. dirus), and <1 % (for Cx. quinquefasciatus). Adulticidal properties were evaluated with unfed females. Ten percent Ca. odorata oil had high knockdown rates against the three mosquito species at 96 % (for Ae. aegypti), 98.4 % (for An. dirus), and 100 % (for Cx. quinquefasciatus), with EC50 values of 6.2, 4.7, and 5.4 %, respectively. It gave moderate mortality rates after 24 and 48 h of exposure. Ca. odorata oil was assessed for repellency to females by using the modified K&D module. Ten percent Ca. odorata oil gave the strongest value against Ae. aegypti, An. dirus, and Cx. quinquefasciatus, with percentage repellency of 66, 92, and 90 %, respectively. This study demonstrates the potential for the essential oil of Ca. odorata essential oil to be used as a botanical insecticide against three mosquito species. PMID:26337270

  9. Genetic variance and genotype-by-environment interaction of immune response in Aedes aegypti (Diptera: Culicidae).

    PubMed

    Moreno-García, Miguel; Lanz-Mendoza, Humberto; Córdoba-Aguilar, Alex

    2010-03-01

    Immune response can be negatively affected by resource limitation, so it is expected that organisms evolve strategies to minimize the impact of this environmental outcome. Phenotypic plasticity in immune response could represent a genetic response to face such situations. We investigated the effects of high and low quality and quantity of food at the larval stage on two important immune components, phenoloxidase activity (PO) and nitric oxide production (NO) measured in adults of the Dengue vector, Aedes aegypti. We reared families to determine the magnitude and pattern of expression of genetic variance, environmental variance and genotype-by-environment interaction (GEI). In addition, we quantified whether there were differences in plastic immune responses in both sexes. Our results indicated additive variance for PO and NO, but rearing environment did not produce differences among individuals. For NO and PO in males, there were large differences among families in plasticity, as indicated by the different slopes produced by each reaction norm. Therefore, there is additive genetic variation in plasticity for NO production and PO activity. One possible interpretation of these results is that different genotypes may be favored to fight pathogens under the different food quality situations. Males and females showed similar overall GEI strategies but there were differences in PO and NO. Males showed a phenotypic correlation between PO and NO, but we did not find genetic correlations between immune parameters in both sexes.

  10. Pyrethroid resistance in Aedes aegypti and Aedes albopictus from Port-au-Prince, Haiti.

    PubMed

    McAllister, Janet C; Godsey, Marvin S; Scott, Mariah L

    2012-12-01

    In Port-au-Prince, Haiti, the status of insecticide resistance has not recently been evaluated for Aedes aegypti (L) and Aedes albopictus (Skuse) populations. No prophylactics exist for dengue, so prevention is only through vector control methods. An earthquake occurred in Haiti on January 12, 2010, with a magnitude of 7.0 Mw that devastated the area. Dengue became a major concern for the humanitarian relief workers that entered the country. Bottle bioassays were conducted in the field on adult mosquitoes reared from larvae collected from the grounds of the U.S. Embassy and from an adjacent neighborhood in eastern Port-au-Prince, Haiti. At the CDC, Fort Collins, CO, bioassays, molecular, and biochemical assays were performed on mosquitoes reared from field-collected eggs. A small percentage of the population was able to survive the diagnostic dose in bioassays run in Haiti. Mosquitoes tested at the CDC demonstrated no phenotypic resistance. A variety of factors could be responsible for the discrepancies between the field and lab data, but temperature and larval nutrition are probably most important. Knowledge of localized resistance and underlying mechanisms helps in making rational decisions in selection of appropriate and effective insecticides in the event of a dengue outbreak.

  11. Indirect effects of cigarette butt waste on the dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Dieng, Hamady; Rajasaygar, Sudha; Ahmad, Abu Hassan; Rawi, Che Salmah Md; Ahmad, Hamdan; Satho, Tomomitsu; Miake, Fumio; Zuharah, Wan Fatma; Fukumitsu, Yuki; Saad, Ahmad Ramli; Abdul Hamid, Suhaila; Vargas, Ronald Enrique Morales; Ab Majid, Abdul Hafiz; Fadzly, Nik; Abu Kassim, Nur Faeza; Hashim, Nur Aida; Abd Ghani, Idris; Abang, Fatimah Bt; AbuBakar, Sazaly

    2014-02-01

    Despite major insecticide-based vector control programs, dengue continues to be a major threat to public health in urban areas. The reasons for this failure include the emergence of insecticide resistance and the narrowing of the spectrum of efficient products. Cigarette butts (CBs), the most commonly discarded piece of waste, also represent a major health hazard to human and animal life. CBs are impregnated with thousands of chemical compounds, many of which are highly toxic and none of which has history of resistance in mosquitoes. This study was performed to examine whether exposure to CB alters various biological parameters of parents and their progeny. We examined whether the mosquito changes its ovipositional behaviors, egg hatching, reproductive capacity, longevity and fecundity in response to CB exposure at three different concentrations. Females tended to prefer microcosms containing CBs for egg deposition than those with water only. There were equivalent rates of eclosion success among larvae from eggs that matured in CB and water environments. We also observed decreased life span among adults that survived CB exposure. Extracts of CB waste have detrimental effects on the fecundity and longevity of its offspring, while being attractive to its gravid females. These results altogether indicate that CB waste indirectly affect key adult life traits of Aedes aegypti and could conceivably be developed as a novel dengue vector control strategy, referring to previously documented direct toxicity on the larval stage. But this will require further research on CB waste effects on non-target organisms including humans.

  12. [Detection of Aedes (Stegomyia) Aegypti L. mosquitoes in Sochi city].

    PubMed

    Riabova, T E; Iunicheva, Iu V; Markovich, N Ia; Ganushkina, L A; Orabeĭ, V G; Sergiev, V P

    2005-01-01

    Few Aedes aegypti females were found when collecting the mosquitoes attacking human beings in the Central District of Sochi in August to September 2001-2004. Ae. aegypti, a vector of dangerous causative agents of diseases, such as yellow and Aden fevers, appeared on the Black Sea coast of the Caucasus is recorded after its long absence. By taking into account the potential epidemic value of Ae. aegypti, it is necessary to make a monitoring in the cities, towns, and settlements to establish the spread, number, and the breading sites of mosquitoes in the given area and to prevent their mass reproduction. The effectiveness of Ae. albopictus as a vector of Aden fever has been established in different regions of the world. Entomological surveys for Ae. albopictus should be made in the areas of Russia where Ae. aegypti mosquitoes were distributed early in the past century, particularly in the southern port towns and settlements of Russia. Ae. albopictus is potentially able to spread to the north further than is Ae. aegypti.

  13. Apoptosis and necrosis during the circadian cycle in the centipede midgut.

    PubMed

    Rost-Roszkowska, M M; Chajec, Ł; Vilimova, J; Tajovský, K

    2016-07-01

    Three types of cells have been distinguished in the midgut epithelium of two centipedes, Lithobius forficatus and Scolopendra cingulata: digestive, secretory, and regenerative cells. According to the results of our previous studies, we decided to analyze the relationship between apoptosis and necrosis in their midgut epithelium and circadian rhythms. Ultrastructural analysis showed that these processes proceed in a continuous manner that is independent of the circadian rhythm in L. forficatus, while in S. cingulata necrosis is activated at midnight. Additionally, the description of apoptosis and necrosis showed no differences between males and females of both species analyzed. At the beginning of apoptosis, the cell cytoplasm becomes electron-dense, apparently in response to shrinkage of the cell. Organelles such as the mitochondria, cisterns of endoplasmic reticulum transform and degenerate. Nuclei gradually assume lobular shapes before the apoptotic cell is discharged into the midgut lumen. During necrosis, however, the cytoplasm of the cell becomes electron-lucent, and the number of organelles decreases. While the digestive cells of about 10 % of L. forficatus contain rickettsia-like pathogens, the corresponding cells in S. cingulata are free of rickettsia. As a result, we can state that apoptosis in L. forficatus is presumably responsible for protecting the organism against infections, while in S. cingulata apoptosis is not associated with the elimination of pathogens. Necrosis is attributed to mechanical damage, and the activation of this process coincides with proliferation of the midgut regenerative cells at midnight in S. cingulata.

  14. Perimicrovillar membrane assembly: the fate of phospholipids synthesised by the midgut of Rhodnius prolixus

    PubMed Central

    Bittencourt-Cunha, Paula Rêgo; Silva-Cardoso, Livia; de Oliveira, Giselle Almeida; da Silva, José Roberto; da Silveira, Alan Barbosa; Kluck, George Eduardo Gabriel; Souza-Lima, Michele; Gondim, Katia Calp; Dansa-Petretsky, Marilvia; Silva, Carlos Peres; Masuda, Hatisaburo; da Silva, Mario Alberto Cardoso; Atella, Georgia Correa

    2013-01-01

    In this study, we describe the fate of fatty acids that are incorporated from the lumen by the posterior midgut epithelium of Rhodnius prolixus and the biosynthesis of lipids. We also demonstrate that neutral lipids (NL) are transferred to the haemolymphatic lipophorin (Lp) and that phospholipids remain in the tissue in which they are organised into perimicrovillar membranes (PMMs). 3H-palmitic acid added at the luminal side of isolated midguts of R. prolixus females was readily absorbed and was used to synthesise phospholipids (80%) and NL (20%). The highest incorporation of 3H-palmitic acid was on the first day after a blood meal. The amounts of diacylglycerol (DG) and triacylglycerol synthesised by the tissue decreased in the presence of Lp in the incubation medium. The metabolic fates of 3H-lipids synthesised by the posterior midgut were followed and it was observed that DG was the major lipid released to Lp particles. However, the majority of phospholipids were not transferred to Lp, but remained in the tissue. The phospholipids that were synthesised and accumulated in the posterior midgut were found to be associated with Rhodnius luminal contents as structural components of PMMs. PMID:23827998

  15. Determination of pH in Regions of the Midguts of Acaridid Mites

    PubMed Central

    Erban, Tomas; Hubert, Jan

    2010-01-01

    The pH of the guts of mites strongly affects their digestive processes. This study was carried out to determine the pH in the guts of 12 species of stored product and house dust mites. Eighteen pH indicators were chosen and offered to the mites in the feeding biotest. Based on the color changes of the indicators, the gut contents of acaridid mites were determined to be within a pH range of 4 to neutral. The gut contents showed a gradient in pH from the anterior to the posterior part. The anterior midgut (ventriculus and caeca) of most species had a pH ranging from 4.5 to 5, or slightly more alkaline for most of the species, while the middle midgut (intercolon/colon) had a pH of 5 to 6. Finally, the pH of the posterior midgut (postcolon) was between 5.5 and 7. Except for Dermatophagoides spp., no remarkable differences in the pH of the gut were observed among the tested species. Dermatophagoides spp. had a more acidic anterior midgut (a pH of 4 to 5) and colon (a pH of 5) with postcolon (a pH of below 6). The results characterizing in vivo conditions in the mite gut offer useful information to study the activity of mite digestive enzymes including their inhibitors and gut microflora. PMID:20572792

  16. Gene expression in midgut tissues of Diaphorina citri: Application to biology and vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We produced a gene expression dataset from the midgut tissues of the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae). The AsCP is the primary vector associated with the spread of a devastating citrus trees disease, huanglongbing (HLB). The occurrence and spread of the AsCP and H...

  17. Midgut gene expression in Asian citrus psyllid (Hemiptera: Psyllidae) Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We produced a gene expression dataset from the midgut tissues of the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae). The AsCP is the primary vector of the bacterium associated with a devastating citrus disease known as huanglongbing (HLB). The occurrence and spread of the AsCP ...

  18. Kazal-type serine proteinase inhibitors in the midgut of Phlebotomus papatasi

    PubMed Central

    Sigle, Leah Theresa; Ramalho-Ortigão, Marcelo

    2013-01-01

    Sandflies (Diptera: Psychodidae) are important disease vectors of parasites of the genus Leishmania, as well as bacteria and viruses. Following studies of the midgut transcriptome of Phlebotomus papatasi, the principal vector of Leishmania major, two non-classical Kazal-type serine proteinase inhibitors were identified (PpKzl1 and PpKzl2). Analyses of expression profiles indicated that PpKzl1 and PpKzl2 transcripts are both regulated by blood-feeding in the midgut of P. papatasi and are also expressed in males, larva and pupa. We expressed a recombinant PpKzl2 in a mammalian expression system (CHO-S free style cells) that was applied to in vitro studies to assess serine proteinase inhibition. Recombinant PpKzl2 inhibited α-chymotrypsin to 9.4% residual activity and also inhibited α-thrombin and trypsin to 33.5% and 63.9% residual activity, suggesting that native PpKzl2 is an active serine proteinase inhibitor and likely involved in regulating digestive enzymes in the midgut. Early stages of Leishmania are susceptible to killing by digestive proteinases in the sandfly midgut. Thus, characterising serine proteinase inhibitors may provide new targets and strategies to prevent transmission of Leishmania. PMID:24037187

  19. Alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides.

    PubMed

    Alves, Stênio Nunes; Serrão, José Eduardo; Melo, Alan Lane

    2010-08-01

    This study describes morphological alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides. To this end, both third and fourth instars of C. quinquefasciatus larvae were exposed for 30 and 60 min to organophosphate (50 ppb), pyrethroids (20 and 30 ppb), and avermectin derivates (1.5 and 54 ppb). Following incubation, pH measurements of the larvae gut were recorded. The fat body and midgut were also analyzed by light and transmission electron microscopy. These studies demonstrate a decrease in the pH of the larvae anterior midgut following exposure to all of the tested insecticides. Histochemical tests revealed a strong reaction for neutral lipids in the control group and a marked decrease in the group exposed to cypermethrin. Furthermore, a weak reaction with acidic lipids in larvae exposed to deltamethrin, temephos, ivermectin and abamectin was also observed. Insecticide-exposed larvae also exhibited cytoplasm granule differences, relative to control larvae. Finally, we noted a small reduction in microvilli size in the apex of digestive cells, although vesicles were found to be present. The destructive changes in the larvae were very similar regardless of the type of insecticide analyzed. These data suggest that alterations in the fat body and midgut are a common response to cellular intoxication.

  20. Midgut serine proteases and alternative host plant utilization in Pieris brassicae L.

    PubMed Central

    Kumar, Rakesh; Bhardwaj, Usha; Kumar, Pawan; Mazumdar-Leighton, Sudeshna

    2015-01-01

    Pieris brassicae L. is a serious pest of cultivated crucifers in several parts of the world. Larvae of P. brassicae also feed prolifically on garden nasturtium (Tropaeolum majus L., of the family Tropaeolaceae). Proteolytic digestion was studied in larvae feeding on multiple hosts. Fourth instars were collected from cauliflower fields before transfer onto detached, aerial tissues of selected host plants in the lab. Variable levels of midgut proteases were detected in larvae fed on different hosts using protein substrates (casein and recombinant RBCL cloned from cauliflower) and diagnostic, synthetic substrates. Qualitative changes in midgut trypsin activities and quantitative changes in midgut chymotrypsin activities were implicated in physiological adaptation of larvae transferred to T. majus. Midgut proteolytic activities were inhibited to different extents by serine protease inhibitors, including putative trypsin inhibitors isolated from herbivore-attacked and herbivore-free leaves of cauliflower (CfTI) and T. majus (TpTI). Transfer of larvae to T. majus significantly influenced feeding parameters but not necessarily when transferred to different tissues of the same host. Results obtained are relevant for devising sustainable pest management strategies, including transgenic approaches using genes encoding plant protease inhibitors. PMID:25873901

  1. Apoptosis and necrosis during the circadian cycle in the centipede midgut.

    PubMed

    Rost-Roszkowska, M M; Chajec, Ł; Vilimova, J; Tajovský, K

    2016-07-01

    Three types of cells have been distinguished in the midgut epithelium of two centipedes, Lithobius forficatus and Scolopendra cingulata: digestive, secretory, and regenerative cells. According to the results of our previous studies, we decided to analyze the relationship between apoptosis and necrosis in their midgut epithelium and circadian rhythms. Ultrastructural analysis showed that these processes proceed in a continuous manner that is independent of the circadian rhythm in L. forficatus, while in S. cingulata necrosis is activated at midnight. Additionally, the description of apoptosis and necrosis showed no differences between males and females of both species analyzed. At the beginning of apoptosis, the cell cytoplasm becomes electron-dense, apparently in response to shrinkage of the cell. Organelles such as the mitochondria, cisterns of endoplasmic reticulum transform and degenerate. Nuclei gradually assume lobular shapes before the apoptotic cell is discharged into the midgut lumen. During necrosis, however, the cytoplasm of the cell becomes electron-lucent, and the number of organelles decreases. While the digestive cells of about 10 % of L. forficatus contain rickettsia-like pathogens, the corresponding cells in S. cingulata are free of rickettsia. As a result, we can state that apoptosis in L. forficatus is presumably responsible for protecting the organism against infections, while in S. cingulata apoptosis is not associated with the elimination of pathogens. Necrosis is attributed to mechanical damage, and the activation of this process coincides with proliferation of the midgut regenerative cells at midnight in S. cingulata. PMID:26277351

  2. Does autophagy in the midgut epithelium of centipedes depend on the day/night cycle?

    PubMed

    Rost-Roszkowska, M M; Chajec, Ł; Vilimova, J; Tajovský, K; Kszuk-Jendrysik, M

    2015-01-01

    The midgut epithelium of two centipedes, Lithobius forficatus and Scolopendra cingulata, is composed of digestive, secretory and regenerative cells. In L. forficatus, the autophagy occurred only in the cytoplasm of the digestive cells as a sporadic process, while in S. cingulata, it occurred intensively in the digestive, secretory and regenerative cells of the midgut epithelium. In both of the species that were analyzed, this process proceeded in a continuous manner and did not depend on the day/night cycle. Ultrastructural analysis showed that the autophagosomes and autolysosomes were located mainly in the apical and perinuclear cytoplasm of the digestive cells in L. forficatus. However, in S. cingulata, the entire cytoplasm was filled with autophagosomes and autolysosomes. Initially the membranes of phagophores surround organelles during autophagosome formation. Autolysosomes result from the fusion of autophagosomes and lysosomes. Residual bodies which are the last stage of autophagy were released into the midgut lumen due to necrosis. Autophagy in the midgut epithelia that were analyzed was confirmed using acid phosphatase and mono-dansyl-cadaverine stainings. PMID:25464151

  3. Intravital imaging of Bacillus thuringiensis Cry1A toxin binding sites in the midgut of silkworm.

    PubMed

    Li, Na; Wang, Jing; Han, Heyou; Huang, Liang; Shao, Feng; Li, Xuepu

    2014-02-15

    Identification of the resistance mechanism of insects against Bacillus thuringiensis Cry1A toxin is becoming an increasingly challenging task. This fact highlights the need for establishing new methods to further explore the molecular interactions of Cry1A toxin with insects and the receptor-binding region of Cry1A toxins for their wider application as biopesticides and a gene source for gene-modified crops. In this contribution, a quantum dot-based near-infrared fluorescence imaging method has been applied for direct dynamic tracking of the specific binding of Cry1A toxins, CrylAa and CrylAc, to the midgut tissue of silkworm. The in vitro fluorescence imaging displayed the higher binding specificity of CrylAa-QD probes compared to CrylAc-QD to the brush border membrane vesicles of midgut from silkworm. The in vivo imaging demonstrated that more CrylAa-QDs binding to silkworm midgut could be effectively and distinctly monitored in living silkworms. Furthermore, frozen section analysis clearly indicated the broader receptor-binding region of Cry1Aa compared to that of Cry1Ac in the midgut part. These observations suggest that the insecticidal activity of Cry toxins may depend on the receptor-binding sites, and this scatheless and visual near-infrared fluorescence imaging could provide a new avenue to study the resistance mechanism to maintain the insecticidal activity of B. thuringiensis toxins. PMID:24252542

  4. FoxK mediates TGF-β signalling during midgut differentiation in flies

    PubMed Central

    Casas-Tinto, Sergio; Gomez-Velazquez, Melisa; Granadino, Begoña; Fernandez-Funez, Pedro

    2008-01-01

    Inductive signals across germ layers are important for the development of the endoderm in vertebrates and invertebrates (Tam, P.P., M. Kanai-Azuma, and Y. Kanai. 2003. Curr. Opin. Genet. Dev. 13:393–400; Nakagoshi, H. 2005. Dev. Growth Differ. 47:383–392). In flies, the visceral mesoderm secretes signaling molecules that diffuse into the underlying midgut endoderm, where conserved signaling cascades activate the Hox gene labial, which is important for the differentiation of copper cells (Bienz, M. 1997. Curr. Opin. Genet. Dev. 7:683–688). We present here a Drosophila melanogaster gene of the Fox family of transcription factors, FoxK, that mediates transforming growth factor β (TGF-β) signaling in the embryonic midgut endoderm. FoxK mutant embryos fail to generate midgut constrictions and lack Labial in the endoderm. Our observations suggest that TGF-β signaling directly regulates FoxK through functional Smad/Mad-binding sites, whereas FoxK, in turn, regulates labial expression. We also describe a new cooperative activity of the transcription factors FoxK and Dfos/AP-1 that regulates labial expression in the midgut endoderm. This regulatory activity does not require direct labial activation by the TGF-β effector Mad. Thus, we propose that the combined activity of the TGF-β target genes FoxK and Dfos is critical for the direct activation of lab in the endoderm. PMID:19075113

  5. Characterization of Plasmodium developmental transcriptomes in Anopheles gambiae midgut reveals novel regulators of malaria transmission.

    PubMed

    Akinosoglou, Karolina A; Bushell, Ellen S C; Ukegbu, Chiamaka Valerie; Schlegelmilch, Timm; Cho, Jee-Sun; Redmond, Seth; Sala, Katarzyna; Christophides, George K; Vlachou, Dina

    2015-02-01

    The passage through the mosquito is a major bottleneck for malaria parasite populations and a target of interventions aiming to block disease transmission. Here, we used DNA microarrays to profile the developmental transcriptomes of the rodent malaria parasite Plasmodium berghei in vivo, in the midgut of Anopheles gambiae mosquitoes, from parasite stages in the midgut blood bolus to sporulating oocysts on the basal gut wall. Data analysis identified several distinct transcriptional programmes encompassing genes putatively involved in developmental processes or in interactions with the mosquito. At least two of these programmes are associated with the ookinete development that is linked to mosquito midgut invasion and establishment of infection. Targeted disruption by homologous recombination of two of these genes resulted in mutant parasites exhibiting notable infection phenotypes. GAMER encodes a short polypeptide with granular localization in the gametocyte cytoplasm and shows a highly penetrant loss-of-function phenotype manifested as greatly reduced ookinete numbers, linked to impaired male gamete release. HADO encodes a putative magnesium phosphatase with distinctive cortical localization along the concave ookinete periphery. Disruption of HADO compromises ookinete development leading to significant reduction of oocyst numbers. Our data provide important insights into the molecular framework underpinning Plasmodium development in the mosquito and identifies two genes with important functions at initial stages of parasite development in the mosquito midgut.

  6. Barber Pole Sign in CT Angiography, Adult Presentation of Midgut Malrotation: A Case Report

    PubMed Central

    Garcelan-Trigo, Juan Arsenio; Tello-Moreno, Manuel; Rabaza-Espigares, Manuel Jesus; Talavera-Martinez, Ildefonso

    2015-01-01

    Adult midgut volvulus is a challenging diagnosis because of its low incidence and nonspecific symptoms. Diagnostic delay and long-term complaints are frequent in this clinical scenario. We reported a patient referred to our diagnostic imaging unit with intermittent abdominal pain, bloating and episodic vomiting for several years. He underwent barium gastrointestinal transit and abdominal ultrasound, which revealed severe gastric dilatation, food retention and slow transit until a depressed duodenojejunal flexure, with malrotation of the midgut and jejunal loops being located in the right upper quadrant. Computed tomography angiography was performed, showing rotation of the small intestine around the mesentery root, suggestive of midgut malrotation. In addition, an abnormal twisted disposition of superior mesenteric artery with corkscrew appearance was seen, shaping the pole-barber sign which was evident in volume rendering three-dimensional reconstructions. The patient underwent scheduled surgical treatment without any complication and had good outcome after hospital discharge and follow-up. Computed tomography plays an important role in evaluation of adult midgut volvulus. In addition, angiographic reconstructions can help us to assess the anatomic disposition of mesenteric vascular supply. Both of these assessments are useful in preoperative management. PMID:26557278

  7. Midgut transcriptome profiling of Anoplophora glabripennis, a lignocellulose degrading Cerambycid beetle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Wood-feeding insects often work in collaboration with microbial symbionts to degrade lignin biopolymers and release glucose and other fermentable sugars from recalcitrant plant cell wall carbohydrates, including cellulose and hemicellulose. Here, we present the midgut transcriptome of la...

  8. Soundscapes and Larval Settlement: Larval Bivalve Responses to Habitat-Associated Underwater Sounds.

    PubMed

    Eggleston, David B; Lillis, Ashlee; Bohnenstiehl, DelWayne R

    2016-01-01

    We quantified the effects of habitat-associated sounds on the settlement response of two species of bivalves with contrasting habitat preferences: (1) Crassostrea virginicia (oyster), which prefers to settle on other oysters, and (2) Mercenaria mercenaria (clam), which settles on unstructured habitats. Oyster larval settlement in the laboratory was significantly higher when exposed to oyster reef sound compared with either off-reef or no-sound treatments. Clam larval settlement did not vary according to sound treatments. Similar to laboratory results, field experiments showed that oyster larval settlement in "larval housings" suspended above oyster reefs was significantly higher compared with off-reef sites.

  9. Development and evaluation of a novel contamination device that targets multiple life-stages of Aedes aegypti

    PubMed Central

    2014-01-01

    Background The increasing global threat of Dengue demands new and easily applicable vector control methods. Ovitraps provide a low-tech and inexpensive means to combat Dengue vectors. Here we describe the development and optimization process of a novel contamination device that targets multiple life-stages of the Aedes aegypti mosquito. Special focus is directed to the diverse array of control agents deployed in this trap, covering adulticidal, larvicidal and autodissemination impacts. Methods Different trap prototypes and their parts are described, including a floater to contaminate alighting gravid mosquitoes. The attractiveness of the trap, different odor lures and floater design were studied using fluorescent powder adhering to mosquito legs and via choice tests. We demonstrate the mosquitocidal impacts of the control agents: a combination of the larvicide pyriproxyfen and the adulticidal fungus Beauveria bassiana. The impact of pyriproxyfen was determined in free-flight dissemination experiments. The effect on larval development inside the trap and in surrounding breeding sites was measured, as well as survival impacts on recaptured adults. Results The developmental process resulted in a design that consists of a black 3 Liter water-filled container with a ring-shaped floater supporting vertically placed gauze dusted with the control agents. On average, 90% of the mosquitoes in the fluorescence experiments made contact with the gauze on the floater. Studies on attractants indicated that a yeast-containing tablet was the most attractive odor lure. Furthermore, the fungus Beauveria bassiana was able to significantly increase mortality of the free-flying adults compared to controls. Dissemination of pyriproxyfen led to >90% larval mortality in alternative breeding sites and 100% larval mortality in the trap itself, against a control mortality of around 5%. Conclusion This ovitrap is a promising new tool in the battle against Dengue. It has proven to be attractive

  10. Prohibitin, an essential protein for Colorado potato beetle larval viability, is relevant to Bacillus thuringiensis Cry3Aa toxicity.

    PubMed

    Ochoa-Campuzano, Camila; Martínez-Ramírez, Amparo C; Contreras, Estefanía; Rausell, Carolina; Real, M Dolores

    2013-11-01

    Bacillus thuringienesis (Bt) Cry toxins constitute the most extensively used environmentally safe biopesticide and their mode of action relies on the interaction of the toxins with membrane proteins in the midgut of susceptible insects that mediate toxicity and insect specificity. Therefore, identification of Bt Cry toxin interacting proteins in the midgut of target insects and understanding their role in toxicity is of great interest to exploit their insecticidal action. Using ligand blot, we demonstrated that Bt Cry3Aa toxin bound to a 30kDa protein in Colorado potato beetle (CPB) larval midgut membrane, identified by sequence homology as prohibitin-1 protein. Prohibitins comprise a highly conserved family of proteins implicated in important cellular processes. We obtained the complete CPB prohibitin-1 DNA coding sequence of 828pb, in silico translated into a 276-amino acid protein. The analysis at the amino acid level showed that the protein contains a prohibitin-homology domain (Band7_prohibitin, cd03401) conserved among prohibitin proteins. A striking feature of the CPB identified prohibitin-1 is the predicted presence of cadherin elements, potential binding sites for Cry toxins described in other Bt susceptible insects. We also showed that CPB prohibitin-1 protein partitioned into both, detergent soluble and insoluble membrane fractions, as well as a prohibitin-2 homologous protein, previously reported to form functional complexes with prohibitin-1 in other organisms. Prohibitin complexes act as membrane scaffolds ensuring the recruitment of membrane proteases to facilitate substrate processing. Accordingly, sequestration of prohibitin-1 by an anti-prohibitin-1 antibody impaired the Cry3Aa toxin inhibition of the proteolytic cleavage of a fluorogenic synthetic substrate of an ADAM-like metalloprotease previously reported to proteolize this toxin. In this work, we also demonstrated that prohibitin-1 RNAi silencing in CPB larvae produced deleterious effects and

  11. Prohibitin, an essential protein for Colorado potato beetle larval viability, is relevant to Bacillus thuringiensis Cry3Aa toxicity.

    PubMed

    Ochoa-Campuzano, Camila; Martínez-Ramírez, Amparo C; Contreras, Estefanía; Rausell, Carolina; Real, M Dolores

    2013-11-01

    Bacillus thuringienesis (Bt) Cry toxins constitute the most extensively used environmentally safe biopesticide and their mode of action relies on the interaction of the toxins with membrane proteins in the midgut of susceptible insects that mediate toxicity and insect specificity. Therefore, identification of Bt Cry toxin interacting proteins in the midgut of target insects and understanding their role in toxicity is of great interest to exploit their insecticidal action. Using ligand blot, we demonstrated that Bt Cry3Aa toxin bound to a 30kDa protein in Colorado potato beetle (CPB) larval midgut membrane, identified by sequence homology as prohibitin-1 protein. Prohibitins comprise a highly conserved family of proteins implicated in important cellular processes. We obtained the complete CPB prohibitin-1 DNA coding sequence of 828pb, in silico translated into a 276-amino acid protein. The analysis at the amino acid level showed that the protein contains a prohibitin-homology domain (Band7_prohibitin, cd03401) conserved among prohibitin proteins. A striking feature of the CPB identified prohibitin-1 is the predicted presence of cadherin elements, potential binding sites for Cry toxins described in other Bt susceptible insects. We also showed that CPB prohibitin-1 protein partitioned into both, detergent soluble and insoluble membrane fractions, as well as a prohibitin-2 homologous protein, previously reported to form functional complexes with prohibitin-1 in other organisms. Prohibitin complexes act as membrane scaffolds ensuring the recruitment of membrane proteases to facilitate substrate processing. Accordingly, sequestration of prohibitin-1 by an anti-prohibitin-1 antibody impaired the Cry3Aa toxin inhibition of the proteolytic cleavage of a fluorogenic synthetic substrate of an ADAM-like metalloprotease previously reported to proteolize this toxin. In this work, we also demonstrated that prohibitin-1 RNAi silencing in CPB larvae produced deleterious effects and

  12. Characterization of proteinases from the midgut of Rhipicephalus (Boophilus) microplus involved in the generation of antimicrobial peptides

    PubMed Central

    2010-01-01

    Background Hemoglobin is a rich source of biologically active peptides, some of which are potent antimicrobials (hemocidins). A few hemocidins have been purified from the midgut contents of ticks. Nonetheless, how antimicrobials are generated in the tick midgut and their role in immunity is still poorly understood. Here we report, for the first time, the contribution of two midgut proteinases to the generation of hemocidins. Results An aspartic proteinase, designated BmAP, was isolated from the midgut of Rhipicephalus (Boophilus) microplus using three chromatographic steps. Reverse transcription-quantitative polymerase chain reaction revealed that BmAP is restricted to the midgut. The other enzyme is a previously characterized midgut cathepsin L-like cysteine proteinase designated BmCL1. Substrate specificities of native BmAP and recombinant BmCL1 were mapped using a synthetic combinatorial peptide library and bovine hemoglobin. BmCL1 preferred substrates containing non-polar residues at P2 subsite and polar residues at P1, whereas BmAP hydrolysed substrates containing non-polar amino acids at P1 and P1'. Conclusions BmAP and BmCL1 generate hemocidins from hemoglobin alpha and beta chains in vitro. We postulate that hemocidins may be important for the control of tick pathogens and midgut flora. PMID:20663211

  13. Ultrastructure of the digestive system and the fate of midgut during embryonic development in Porcellio scaber (Crustacea: Isopoda).

    PubMed

    Strus, Jasna; Klepal, Waltraud; Repina, Janja; Tusek-Znidaric, Magda; Milatovic, Masa; Pipan, Ziva

    2008-07-01

    Microscopic anatomy of the digestive system in embryos and larvae of the terrestrial isopod crustacean Porcellio scaber was investigated by light bright field, fluorescence and electron microscopy. During marsupial ontogenetic development the event-dependent staging was used to discriminate the various embryonic stages. At the late embryo stage the differentiation of the ectodermal part of the gut into the complex filtering foregut and the hindgut with absorptive and transporting functions is accomplished. The gut of the marsupial manca larva is fully developed and similar to that of the adult. In early embryos the endodermal midgut gland primordia are filled with yolk and lipid globules. In late embryos the epithelium of paired midgut gland tubes is composed of two cell types; one of them exhibits orange autofluorescence. The endodermal cells located between the foregut and the midgut glands of late embryos form the prospective midgut. The cells have electron dense cytoplasm, abundant glycogen fields, endoplasmic reticulum, dictyosomes and numerous vesicles. In the adults the endodermal cells of the midgut remain only in the midgut gland ducts which connect the midgut glands and the foregut. Details of the cellular ultrastructure and morphogenesis of the ectodermal and endodermal parts of the digestive system during embryonic development of Porcellio scaber provide data for further phylogenetic and comparative studies in peracaridan crustaceans and other arthropods.

  14. Larval nervous systems: true larval and precocious adult.

    PubMed

    Nielsen, Claus

    2015-02-15

    The apical organ of ciliated larvae of cnidarians and bilaterians is a true larval organ that disappears before or at metamorphosis. It appears to be sensory, probably involved in metamorphosis, but knowledge is scant. The ciliated protostome larvae show ganglia/nerve cords that are retained as the adult central nervous system (CNS). Two structures can be recognized, viz. a pair of cerebral ganglia, which form the major part of the adult brain, and a blastoporal (circumblastoporal) nerve cord, which becomes differentiated into a perioral loop, paired or secondarily fused ventral nerve cords and a small perianal loop. The anterior loop becomes part of the brain. This has been well documented through cell-lineage studies in a number of spiralians, and homologies with similar structures in the ecdysozoans are strongly indicated. The deuterostomes are generally difficult to interpret, and the nervous systems of echinoderms and enteropneusts appear completely enigmatic. The ontogeny of the chordate CNS can perhaps be interpreted as a variation of the ontogeny of the blastoporal nerve cord of the protostomes, and this is strongly supported by patterns of gene expression. The presence of 'deuterostomian' blastopore fates both in an annelid and in a mollusk, which are both placed in families with the 'normal' spiralian gastrulation type, and in the chaetognaths demonstrates that the chordate type of gastrulation could easily have evolved from the spiralian type. This indicates that the latest common ancestor of the deuterostomes was very similar to the latest common pelago-benthic ancestor of the protostomes as described by the trochaea theory, and that the neural tube of the chordates is morphologically ventral.

  15. Detecting larval export from marine reserves

    PubMed Central

    Pelc, R. A.; Warner, R. R.; Gaines, S. D.; Paris, C. B.

    2010-01-01

    Marine reserve theory suggests that where large, productive populations are protected within no-take marine reserves, fished areas outside reserves will benefit through the spillover of larvae produced in the reserves. However, empirical evidence for larval export has been sparse. Here we use a simple idealized coastline model to estimate the expected magnitude and spatial scale of larval export from no-take marine reserves across a range of reserve sizes and larval dispersal scales. Results suggest that, given the magnitude of increased production typically found in marine reserves, benefits from larval export are nearly always large enough to offset increased mortality outside marine reserves due to displaced fishing effort. However, the proportional increase in recruitment at sites outside reserves is typically small, particularly for species with long-distance (on the order of hundreds of kilometers) larval dispersal distances, making it very difficult to detect in field studies. Enhanced recruitment due to export may be detected by sampling several sites at an appropriate range of distances from reserves or at sites downcurrent of reserves in systems with directional dispersal. A review of existing empirical evidence confirms the model's suggestion that detecting export may be difficult without an exceptionally large differential in production, short-distance larval dispersal relative to reserve size, directional dispersal, or a sampling scheme that encompasses a broad range of distances from the reserves. PMID:20181570

  16. Exploring the molecular basis of insecticide resistance in the dengue vector Aedes aegypti: a case study in Martinique Island (French West Indies)

    PubMed Central

    Marcombe, Sébastien; Poupardin, Rodolphe; Darriet, Frederic; Reynaud, Stéphane; Bonnet, Julien; Strode, Clare; Brengues, Cecile; Yébakima, André; Ranson, Hilary; Corbel, Vincent; David, Jean-Philippe

    2009-01-01

    Background The yellow fever mosquito Aedes aegypti is a major vector of dengue and hemorrhagic fevers, causing up to 100 million dengue infections every year. As there is still no medicine and efficient vaccine available, vector control largely based on insecticide treatments remains the only method to reduce dengue virus transmission. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides. Resistance of Ae. aegypti to chemical insecticides has been reported worldwide and the underlying molecular mechanisms, including the identification of enzymes involved in insecticide detoxification are not completely understood. Results The present paper investigates the molecular basis of insecticide resistance in a population of Ae. aegypti collected in Martinique (French West Indies). Bioassays with insecticides on adults and larvae revealed high levels of resistance to organophosphate and pyrethroid insecticides. Molecular screening for common insecticide target-site mutations showed a high frequency (71%) of the sodium channel 'knock down resistance' (kdr) mutation. Exposing mosquitoes to detoxification enzymes inhibitors prior to bioassays induced a significant increased susceptibility of mosquitoes to insecticides, revealing the presence of metabolic-based resistance mechanisms. This trend was biochemically confirmed by significant elevated activities of cytochrome P450 monooxygenases, glutathione S-transferases and carboxylesterases at both larval and adult stages. Utilization of the microarray Aedes Detox Chip containing probes for all members of detoxification and other insecticide resistance-related enzymes revealed the significant constitutive over-transcription of multiple detoxification genes at both larval and adult stages. The over-transcription of detoxification genes in the resistant strain was confirmed by using real-time quantitative RT-PCR. Conclusion These results suggest

  17. Tackling the growing threat of dengue: Phyllanthus niruri-mediated synthesis of silver nanoparticles and their mosquitocidal properties against the dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Suresh, Udaiyan; Murugan, Kadarkarai; Benelli, Giovanni; Nicoletti, Marcello; Barnard, Donald R; Panneerselvam, Chellasamy; Kumar, Palanisamy Mahesh; Subramaniam, Jayapal; Dinesh, Devakumar; Chandramohan, Balamurugan

    2015-04-01

    Mosquitoes are vectors of devastating pathogens and parasites, causing millions of deaths every year. Dengue is a mosquito-borne viral infection found in tropical and subtropical regions around the world. Recently, transmission has strongly increased in urban and semiurban areas, becoming a major international public health concern. Aedes aegypti (Diptera: Culicidae) is the primary vector of dengue. The use of synthetic insecticides to control Aedes mosquitoes lead to high operational costs and adverse nontarget effects. In this scenario, eco-friendly control tools are a priority. We proposed a novel method to synthesize silver nanoparticles using the aqueous leaf extract of Phyllanthus niruri, a cheap and nontoxic material. The UV-vis spectrum of the aqueous medium containing silver nanostructures showed a peak at 420 nm corresponding to the surface plasmon resonance band of nanoparticles. SEM analyses of the synthesized nanoparticles showed a mean size of 30-60 nm. EDX spectrum showed the chemical composition of the synthesized nanoparticles. XRD highlighted that the nanoparticles are crystalline in nature with face-centered cubic geometry. Fourier transform infrared spectroscopy (FTIR) of nanoparticles exhibited prominent peaks 3,327.63, 2,125.87, 1,637.89, 644.35, 597.41, and 554.63 cm(-1). In laboratory assays, the aqueous extract of P. niruri was toxic against larval instars (I-IV) and pupae of A. aegypti. LC50 was 158.24 ppm (I), 183.20 ppm (II), 210.53 ppm (III), 210.53 ppm (IV), and 358.08 ppm (pupae). P. niruri-synthesized nanoparticles were highly effective against A. aegypti, with LC50 of 3.90 ppm (I), 5.01 ppm (II), 6.2 ppm (III), 8.9 ppm (IV), and 13.04 ppm (pupae). In the field, the application of silver nanoparticles (10 × LC50) lead to A. aegypti larval reduction of 47.6%, 76.7% and 100%, after 24, 48, and 72 h, while the P. niruri extract lead to 39.9%, 69.2 % and 100 % of reduction, respectively. In adulticidal experiments, P. niruri extract

  18. Ovicidal, larvicidal and adulticidal properties of Asparagus racemosus (Willd.) (Family: Asparagaceae) root extracts against filariasis (Culex quinquefasciatus), dengue (Aedes aegypti) and malaria (Anopheles stephensi) vector mosquitoes (Diptera: Culicidae).

    PubMed

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-04-01

    Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The present investigation was undertaken to study the ovicidal, larvicidal and adulticidal activities of crude hexane, ethyl acetate, benzene, chloroform and methanol extracts of root of Asparagus racemosus were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae). The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of Asparagus racemosus against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi exerted 100% mortality (zero hatchability) at 375, 300 and 225 ppm, respectively. Control eggs showed 99-100% hatchability. The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of root of Asparagus racemosus against the larvae of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi with the LC50 and LC90 values were 115.13, 97.71 and 90.97 ppm and 210.96, 179.92, and 168.82 ppm, respectively. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and then died. Among the extracts tested, the highest adulticidal activity was observed in

  19. Field evaluations of disposable sticky lures for surveillance of Aedes aegypti (Stegomyia aegypti) and Culex quinquefasciatus in Jakarta.

    PubMed

    Kay, B H; Brown, M D; Siti, Z; Bangs, M J

    2013-09-01

    From December 1997 to April 1998, disposable sticky lures (1608 lure days) were trialled in homes in north Jakarta, Indonesia as surveillance tools for Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) and Culex quinquefasciatus (Diptera: Culicidae), referenced to indoor resting adult collections (92 × 10 min). The lures collected 89.4% of the total of 1339 Ae. aegypti and 92.1% of the total of 1272 Cx. quinquefasciatus collected by all methods. Because there were no significant differences with respect to numbers collected in bedrooms, living rooms and kitchens, bedrooms were selected for subsequent trials for reasons of convenience. The main trials involved a replicated complete block design with L-lysine and sodium carbonate. Lures without attractant or with four different dilutions of L-lysine collected 3.4-8.5 times more Ae. aegypti and 4.2-8.1 times more Cx. quinquefasciatus than were collected by mouth aspirator. Lures with or without dilutions of sodium carbonate collected 2.7-5.0 times more Ae. aegypti and 1.8-4.2 times more Cx. quinquefasciatus than aspirator collections. The precision associated with catches of sticky lures was better than that for aspirator collections. Although olfactants generally improved the numbers of mosquitoes collected, the differences in catch between lures with and without attractants were usually non-significant. Any deficit in catch may be offset by increasing the surveillance period to ≥30 days to detect all four dengue serotypes from infected mosquitoes.

  20. The impact of the Bacillus subtilis SPB1 biosurfactant on the midgut histology of Spodoptera littoralis (Lepidoptera: Noctuidae) and determination of its putative receptor.

    PubMed

    Ghribi, Dhouha; Abdelkefi-Mesrati, Lobna; Boukedi, Hanen; Elleuch, Mouna; Ellouze-Chaabouni, Semia; Tounsi, Slim

    2012-02-01

    SPB1 is a Bacillus subtilis strain producing a lipopeptide biosurfactant. The insecticidal activity of this biosurfactant was evaluated against the Egyptian cotton leaf worm (Spodoptera littoralis). It displayed toxicity with an LC(50) of 251 ng/cm(2). The histopathological changes occurred in the larval midgut of S. littoralis treated with B. subtilis SPB1 biosurfactant were vesicle formation in the apical region, cellular vacuolization and destruction of epithelial cells and their boundaries. Ligand-blotting experiments with S. littoralis brush border membrane vesicles showed binding of SPB1 biosurfactant to a protein of 45 kDa corresponding to its putative receptor. The latter differs in molecular size from those recognized by Bacillus thuringiensis Vip3A and Cry1C toxins, commonly known by their activity against S. littoralis. This result wires the application of B. subtilis biosurfactant for effective control of S. littoralis larvae, particularly in the cases where S. littoralis will develop resistance against B. thuringiensis toxins. PMID:22079884

  1. The midgut cadherin-like gene is not associated with resistance to Bacillus thuringiensis toxin Cry1Ac in Plutella xylostella (L.).

    PubMed

    Guo, Zhaojiang; Kang, Shi; Zhu, Xun; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhang, Youjun

    2015-03-01

    The Gram-positive bacterium Bacillus thuringiensis (Bt) produces Cry toxins that have been used to control important agricultural pests. Evolution of resistance in target pests threatens the effectiveness of these toxins when used either in sprayed biopesticides or in Bt transgenic crops. Although alterations of the midgut cadherin-like receptor can lead to Bt Cry toxin resistance in many insects, whether the cadherin gene is involved in Cry1Ac resistance of Plutella xylostella (L.) remains unclear. Here, we present experimental evidence that resistance to Cry1Ac or Bt var. kurstaki (Btk) in P. xylostella is not due to alterations of the cadherin gene. The bona fide P. xylostella cadherin cDNA sequence was cloned and analyzed, and comparisons of the cadherin cDNA sequence among susceptible and resistant P. xylostella strains confirmed that Cry1Ac resistance was independent of mutations in this gene. In addition, real-time quantitative PCR (qPCR) indicated that cadherin transcript levels did not significantly differ among susceptible and resistant P. xylostella strains. RNA interference (RNAi)-mediated suppression of cadherin gene expression did not affect larval susceptibility to Cry1Ac toxin. Furthermore, genetic linkage assays using four cadherin gDNA allelic biomarkers confirmed that the cadherin gene is not linked to resistance against Cry1Ac in P. xylostella. Taken together, our findings demonstrate that Cry1Ac resistance of P. xylostella is independent of the cadherin gene. PMID:25595643

  2. Plasmodium falciparum evades mosquito immunity by disrupting JNK-mediated apoptosis of invaded midgut cells

    PubMed Central

    Ramphul, Urvashi N.; Garver, Lindsey S.; Molina-Cruz, Alvaro; Canepa, Gaspar E.; Barillas-Mury, Carolina

    2015-01-01

    The malaria parasite, Plasmodium, must survive and develop in the mosquito vector to be successfully transmitted to a new host. The Plasmodium falciparum Pfs47 gene is critical for malaria transmission. Parasites that express Pfs47 (NF54 WT) evade mosquito immunity and survive, whereas Pfs47 knockouts (KO) are efficiently eliminated by the complement-like system. Two alternative approaches were used to investigate the mechanism of action of Pfs47 on immune evasion. First, we examined whether Pfs47 affected signal transduction pathways mediating mosquito immune responses, and show that the Jun-N-terminal kinase (JNK) pathway is a key mediator of Anopheles gambiae antiplasmodial responses to P. falciparum infection and that Pfs47 disrupts JNK signaling. Second, we used microarrays to compare the global transcriptional responses of A. gambiae midguts to infection with WT and KO parasites. The presence of Pfs47 results in broad and profound changes in gene expression in response to infection that are already evident 12 h postfeeding, but become most prominent at 26 h postfeeding, the time when ookinetes invade the mosquito midgut. Silencing of 15 differentially expressed candidate genes identified caspase-S2 as a key effector of Plasmodium elimination in parasites lacking Pfs47. We provide experimental evidence that JNK pathway regulates activation of caspases in Plasmodium-invaded midgut cells, and that caspase activation is required to trigger midgut epithelial nitration. Pfs47 alters the cell death pathway of invaded midgut cells by disrupting JNK signaling and prevents the activation of several caspases, resulting in an ineffective nitration response that makes the parasite undetectable by the mosquito complement-like system. PMID:25552553

  3. Midgut Transcriptome of the Cockroach Periplaneta americana and Its Microbiota: Digestion, Detoxification and Oxidative Stress Response

    PubMed Central

    Zhang, Jianhua; Zhang, Yixi; Li, Jingjing; Liu, Meiling; Liu, Zewen

    2016-01-01

    The cockroach, Periplaneta americana, is an obnoxious and notorious pest of the world, with a strong ability to adapt to a variety of complex environments. However, the molecular mechanism of this adaptability is mostly unknown. In this study, the genes and microbiota composition associated with the adaptation mechanism were studied by analyzing the transcriptome and 16S rDNA pyrosequencing of the P. americana midgut, respectively. Midgut transcriptome analysis identified 82,905 unigenes, among which 64 genes putatively involved in digestion (11 genes), detoxification (37 genes) and oxidative stress response (16 genes) were found. Evaluation of gene expression following treatment with cycloxaprid further revealed that the selected genes (CYP6J1, CYP4C1, CYP6K1, Delta GST, alpha-amylase, beta-glucosidase and aminopeptidase) were upregulated at least 2.0-fold at the transcriptional level, and four genes were upregulated more than 10.0-fold. An interesting finding was that three digestive enzymes positively responded to cycloxaprid application. Tissue expression profiles further showed that most of the selected genes were midgut-biased, with the exception of CYP6K1. The midgut microbiota composition was obtained via 16S rDNA pyrosequencing and was found to be mainly dominated by organisms from the Firmicutes phylum, among which Clostridiales, Lactobacillales and Burkholderiales were the main orders which might assist the host in the food digestion or detoxification of noxious compounds. The preponderant species, Clostridium cellulovorans, was previously reported to degrade lignocellulose efficiently in insects. The abundance of genes involved in digestion, detoxification and response to oxidative stress, and the diversity of microbiota in the midgut might provide P. americana high capacity to adapt to complex environments. PMID:27153200

  4. The global compendium of Aedes aegypti and Ae. albopictus occurrence.

    PubMed

    Kraemer, Moritz U G; Sinka, Marianne E; Duda, Kirsten A; Mylne, Adrian; Shearer, Freya M; Brady, Oliver J; Messina, Jane P; Barker, Christopher M; Moore, Chester G; Carvalho, Roberta G; Coelho, Giovanini E; Van Bortel, Wim; Hendrickx, Guy; Schaffner, Francis; Wint, G R William; Elyazar, Iqbal R F; Teng, Hwa-Jen; Hay, Simon I

    2015-01-01

    Aedes aegypti and Ae. albopictus are the main vectors transmitting dengue and chikungunya viruses. Despite being pathogens of global public health importance, knowledge of their vectors' global distribution remains patchy and sparse. A global geographic database of known occurrences of Ae. aegypti and Ae. albopictus between 1960 and 2014 was compiled. Herein we present the database, which comprises occurrence data linked to point or polygon locations, derived from peer-reviewed literature and unpublished studies including national entomological surveys and expert networks. We describe all data collection processes, as well as geo-positioning methods, database management and quality-control procedures. This is the first comprehensive global database of Ae. aegypti and Ae. albopictus occurrence, consisting of 19,930 and 22,137 geo-positioned occurrence records respectively. Both datasets can be used for a variety of mapping and spatial analyses of the vectors and, by inference, the diseases they transmit.

  5. Mathematical model of temephos resistance in Aedes aegypti mosquito population

    NASA Astrophysics Data System (ADS)

    Aldila, D.; Nuraini, N.; Soewono, E.; Supriatna, A. K.

    2014-03-01

    Aedes aegypti is the main vector of dengue disease in many tropical and sub-tropical countries. Dengue became major public concern in these countries due to the unavailability of vaccine or drugs for dengue disease in the market. Hence, the only way to control the spread of DF and DHF is by controlling the vectors carrying the disease, for instance with fumigation, temephos or genetic manipulation. Many previous studies conclude that Aedes aegypti may develop resistance to many kind of insecticide, including temephos. Mathematical model for transmission of temephos resistance in Aedes aegypti population is discussed in this paper. Nontrivial equilibrium point of the system and the corresponding existence are shown analytically. The model analysis have shown epidemiological trends condition that permits the coexistence of nontrivial equilibrium is given analytically. Numerical results are given to show parameter sensitivity and some cases of worsening effect values for illustrating possible conditions in the field.

  6. Effect of temperature on the population dynamics of Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Tokachil, Mohd Najir

    2015-10-01

    Aedes aegypti is one of the main vectors in the transmission of dengue fever. Its abundance may cause the spread of the disease to be more intense. In the study of its biological life cycle, temperature was found to increase the development rate of each stage of this species and thus, accelerate the process of the development from egg to adult. In this paper, a Lefkovitch matrix model will be used to study the stage-structured population dynamics of Aedes aegypti. In constructing the transition matrix, temperature will be taken into account. As a case study, temperature recorded at the Subang Meteorological Station for year 2006 until 2010 will be used. Population dynamics of Aedes aegypti at maximum, average and minimum temperature for each year will be simulated and compared. It is expected that the higher the temperature, the faster the mosquito will breed. The result will be compared to the number of dengue fever incidences to see their relationship.

  7. Stage-Structured Population Dynamics of AEDES AEGYPTI

    NASA Astrophysics Data System (ADS)

    Yusoff, Nuraini; Budin, Harun; Ismail, Salemah

    Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.

  8. [Lethal effect of Cuban Myrtaceae on Aedes aegypti (Diptera Cuilicidae)].

    PubMed

    Aguilera, Lucita; Navarro, Agustín; Tacoronte, Juan E; Leyva, Maureen; Marquetti, María C

    2003-01-01

    The biological activity of the essential foliar oils from 2 Cuban endemic Myrtaceae: Eugenia melanadenia and Psidium rotundatum on A. aegypti larvae was evaluated for the first time at the laboratory level. The probit-log analysis of the results showed the larvicidal effect of both oils with values of CL50 = 0.0085% and CL95 = 0.0104% for E. melanadenia and CL50 = 0.0063% and CL95 = 0.0071% for O. rotundatum. Besides, the diagnostic concentration for both essential oils are given and the possible implications of these findings on field populations of A. aegypti are suggessted. PMID:15849965

  9. Metacommunity patterns in larval odonates.

    PubMed

    McCauley, Shannon J; Davis, Christopher J; Relyea, Rick A; Yurewicz, Kerry L; Skelly, David K; Werner, Earl E

    2008-11-01

    The growth of metacommunity ecology as a subdiscipline has increased interest in how processes at different spatial scales structure communities. However, there is still a significant knowledge gap with respect to relating the action of niche- and dispersal-assembly mechanisms to observed species distributions across gradients. Surveys of the larval dragonfly community (Odonata: Anisoptera) in 57 lakes and ponds in southeast Michigan were used to evaluate hypotheses about the processes regulating community structure in this system. We considered the roles of both niche- and dispersal-assembly processes in determining patterns of species richness and composition across a habitat gradient involving changes in the extent of habitat permanence, canopy cover, area, and top predator type. We compared observed richness patterns and species distributions in this system to patterns predicted by four general community models: species sorting related to adaptive trade-offs, a developmental constraints hypothesis, dispersal assembly, and a neutral community assemblage. Our results supported neither the developmental constraints nor the neutral-assemblage models. Observed patterns of richness and species distributions were consistent with patterns expected when adaptive tradeoffs and dispersal-assembly mechanisms affect community structure. Adaptive trade-offs appeared to be important in limiting the distributions of species which segregate across the habitat gradient. However, dispersal was important in shaping the distributions of species that utilize habitats with a broad range of hydroperiods and alternative top predator types. Our results also suggest that the relative importance of these mechanisms may change across this habitat gradient and that a metacommunity perspective which incorporates both niche- and dispersal-assembly processes is necessary to understand how communities are organized. PMID:18781330

  10. Insecticide resistance and, efficacy of space spraying and larviciding in the control of dengue vectors Aedes aegypti and Aedes albopictus in Sri Lanka.

    PubMed

    Karunaratne, S H P P; Weeraratne, T C; Perera, M D B; Surendran, S N

    2013-09-01

    Unprecedented incidence of dengue has been recorded in Sri Lanka in recent times. Source reduction and use of insecticides in space spraying/fogging and larviciding, are the primary means of controlling the vector mosquitoes Aedes aegypti and Ae. albopictus in the island nation. A study was carried out to understand insecticide cross-resistance spectra and mechanisms of insecticide resistance of both these vectors from six administrative districts, i.e. Kandy, Kurunegala, Puttalam, Gampaha, Ratnapura and Jaffna, of Sri Lanka. Efficacy of the recommended dosages of frequently used insecticides in space spraying and larviciding in dengue vector control programmes was also tested. Insecticide bioassay results revealed that, in general, both mosquito species were highly resistant to DDT but susceptible to propoxur and malathion except Jaffna Ae. aegypti population. Moderate resistance to malathion shown by Jaffna Ae. aegypti population correlated with esterase and malathion carboxylesterase activities of the population. High levels of acetylcholinesterase (AChE) insensitivity in the absence of malathion and propoxur resistance may be due to non-synaptic forms of AChE proteins. Moderate pyrethroid resistance in the absence of high monooxygenase levels indicated the possible involvement of 'kdr' type resistance mechanism in Sri Lankan dengue vectors. Results of the space spraying experiments revealed that 100% mortality at a 10 m distance and >50% mortality at a 50 m distance can be achieved with malathion, pesguard and deltacide even in a ground with dense vegetation. Pesguard and deltacide spraying gave 100% mortality up to 50 m distance in open area and areas with little vegetation. Both species gave >50% mortalities for deltacide at a distance of 75 m in a dense vegetation area. Larval bioassays conducted in the laboratory showed that a 1 ppm temephos solution can maintain a larval mortality rate of 100% for ten months, and the mortality rate declined to 0% in the

  11. Novel methodologies in marine fish larval nutrition.

    PubMed

    Conceição, Luis E C; Aragão, Cláudia; Richard, Nadège; Engrola, Sofia; Gavaia, Paulo; Mira, Sara; Dias, Jorge

    2010-03-01

    Major gaps in knowledge on fish larval nutritional requirements still remain. Small larval size, and difficulties in acceptance of inert microdiets, makes progress slow and cumbersome. This lack of knowledge in fish larval nutritional requirements is one of the causes of high mortalities and quality problems commonly observed in marine larviculture. In recent years, several novel methodologies have contributed to significant progress in fish larval nutrition. Others are emerging and are likely to bring further insight into larval nutritional physiology and requirements. This paper reviews a range of new tools and some examples of their present use, as well as potential future applications in the study of fish larvae nutrition. Tube-feeding and incorporation into Artemia of (14)C-amino acids and lipids allowed studying Artemia intake, digestion and absorption and utilisation of these nutrients. Diet selection by fish larvae has been studied with diets containing different natural stable isotope signatures or diets where different rare metal oxides were added. Mechanistic modelling has been used as a tool to integrate existing knowledge and reveal gaps, and also to better understand results obtained in tracer studies. Population genomics may assist in assessing genotype effects on nutritional requirements, by using progeny testing in fish reared in the same tanks, and also in identifying QTLs for larval stages. Functional genomics and proteomics enable the study of gene and protein expression under various dietary conditions, and thereby identify the metabolic pathways which are affected by a given nutrient. Promising results were obtained using the metabolic programming concept in early life to facilitate utilisation of certain nutrients at later stages. All together, these methodologies have made decisive contributions, and are expected to do even more in the near future, to build a knowledge basis for development of optimised diets and feeding regimes for

  12. Household Wastes as Larval Habitats of Dengue Vectors: Comparison between Urban and Rural Areas of Kolkata, India

    PubMed Central

    Banerjee, Soumyajit; Aditya, Gautam; Saha, Goutam K.

    2015-01-01

    Porcelain and plastic materials constitute bulk of household wastes. Owing to resistibility and slow degradability that accounts for higher residence time, these materials qualify as potential hazardous wastes. Retention of water permits these wastes to form a congenial biotope for the breeding of different vector mosquitoes. Thus porcelain and plastic wastes pose a risk from public health viewpoint. This proposition was validated through the study on the porcelain and plastic household wastes as larval habitats of Dengue vectors (Aedes spp.) in rural and urban areas around Kolkata, India. The wastes were characterized in terms of larval productivity, seasonal variation and a comparison between urban and rural areas was made using data of two subsequent years. The number of wastes positive as larval habitats and their productivity of Aedes spp. varied among the types of household wastes with reference to months and location. Multivariate analysis revealed significant differences in the larval productivity of the household wastes based on the materials, season, and urban–rural context. Results of Discriminant Analysis indicated differences in abundance of Ae. aegypti and Ae. albopictus for the urban and rural areas. The porcelain and plastic wastes were more productive in urban areas compared to the rural areas, indicating a possible difference in the household waste generation. A link between household wastes with Aedes productivity is expected to increase the risk of dengue epidemics if waste generation is continued without appropriate measures to limit addition to the environment. Perhaps, alternative strategies and replacement of materials with low persistence time can reduce this problem of waste and mosquito production. PMID:26447690

  13. Household Wastes as Larval Habitats of Dengue Vectors: Comparison between Urban and Rural Areas of Kolkata, India.

    PubMed

    Banerjee, Soumyajit; Aditya, Gautam; Saha, Goutam K

    2015-01-01

    Porcelain and plastic materials constitute bulk of household wastes. Owing to resistibility and slow degradability that accounts for higher residence time, these materials qualify as potential hazardous wastes. Retention of water permits these wastes to form a congenial biotope for the breeding of different vector mosquitoes. Thus porcelain and plastic wastes pose a risk from public health viewpoint. This proposition was validated through the study on the porcelain and plastic household wastes as larval habitats of Dengue vectors (Aedes spp.) in rural and urban areas around Kolkata, India. The wastes were characterized in terms of larval productivity, seasonal variation and a comparison between urban and rural areas was made using data of two subsequent years. The number of wastes positive as larval habitats and their productivity of Aedes spp. varied among the types of household wastes with reference to months and location. Multivariate analysis revealed significant differences in the larval productivity of the household wastes based on the materials, season, and urban-rural context. Results of Discriminant Analysis indicated differences in abundance of Ae. aegypti and Ae. albopictus for the urban and rural areas. The porcelain and plastic wastes were more productive in urban areas compared to the rural areas, indicating a possible difference in the household waste generation. A link between household wastes with Aedes productivity is expected to increase the risk of dengue epidemics if waste generation is continued without appropriate measures to limit addition to the environment. Perhaps, alternative strategies and replacement of materials with low persistence time can reduce this problem of waste and mosquito production. PMID:26447690

  14. [Estimation of the biological age in males of the taiga tick (Ixodes persulcatus: Ixodinae) by fat reserves in the midgut].

    PubMed

    Grigor'eva, L A

    2012-01-01

    Some criteria for the estimation of the biological and calendar age by the fat storage in midgut cells of Ixodes persulcatus males were established on the basis of examination of ticks from the laboratory culture.

  15. The heterodimeric glycoprotein hormone, GPA2/GPB5, regulates ion transport across the hindgut of the adult mosquito, Aedes aegypti.

    PubMed

    Paluzzi, Jean-Paul; Vanderveken, Mark; O'Donnell, Michael J

    2014-01-01

    A family of evolutionarily old hormones is the glycoprotein cysteine knot-forming heterodimers consisting of alpha- (GPA) and beta-subunits (GPB), which assemble by noncovalent bonds. In mammals, a common glycoprotein hormone alpha-subunit (GPA1) pairs with unique beta-subunits that establish receptor specificity, forming thyroid stimulating hormone (GPA1/TSHβ) and the gonadotropins luteinizing hormone (GPA1/LHβ), follicle stimulating hormone (GPA1/FSHβ), choriogonadotropin (GPA1/CGβ). A novel glycoprotein heterodimer was identified in vertebrates by genome analysis, called thyrostimulin, composed of two novel subunits, GPA2 and GPB5, and homologs occur in arthropods, nematodes and cnidarians, implying that this neurohormone system existed prior to the emergence of bilateral metazoans. In order to discern possible physiological roles of this hormonal signaling system in mosquitoes, we have isolated the glycoprotein hormone genes producing the alpha- and beta-subunits (AedaeGPA2 and AedaeGPB5) and assessed their temporal expression profiles in the yellow and dengue-fever vector, Aedes aegypti. We have also isolated a putative receptor for this novel mosquito hormone, AedaeLGR1, which contains features conserved with other glycoprotein leucine-rich repeating containing G protein-coupled receptors. AedaeLGR1 is expressed in tissues of the alimentary canal such as the midgut, Malpighian tubules and hindgut, suggesting that this novel mosquito glycoprotein hormone may regulate ionic and osmotic balance. Focusing on the hindgut in adult stage A. aegypti, where AedaeLGR1 was highly enriched, we utilized the Scanning Ion-selective Electrode Technique (SIET) to determine if AedaeGPA2/GPB5 modulated cation transport across this epithelial tissue. Our results suggest that AedaeGPA2/GPB5 does indeed participate in ionic and osmotic balance, since it appears to inhibit natriuresis and promote kaliuresis. Taken together, our findings imply this hormone may play an important

  16. Laboratory evaluation of pyriproxyfen and spinosad, alone and in combination, against Aedes aegypti larvae.

    PubMed

    Darriet, Frederic; Corbel, Vincent

    2006-11-01

    In this study, the efficacy of pyriproxyfen and spinosad, alone and in combination, was evaluated against the dengue vector Aedes aegypti (L.). Larval bioassays were carried out on susceptible mosquito larvae to determine the concentration-mortality responses of mosquitoes exposed to each insecticide alone and in mixture. Synergism between pyriproxyfen and spinosad was determined by the calculation of a combination index (CI) by using the isobologram method. For pyriproxyfen, LC50 and LC95 were 1.1 x 10(-4) (1.0 x 10(-4)-1.1 x 10(-4)) and 3.2 x 10(-4) (2.9 x 10(-4)-3.6 x 10(-4)) mg/liter, respectively. Pyriproxyfen acted at very low concentrations by inhibiting the adult emergence of Ae. aegypti (97% inhibition rates at 3.3 x 10(-4) mg/liter). Spinosad activity was -500 times lower than that of pyriproxyfen against the Bora strain, with LC50 and LC95 values estimated at 0.055 (0.047-0.064) and 0.20 (0.15-0.27) mg/liter, respectively. A binary mixture of pyriproxyfen and spinosad was realized at the ratio 1:500 by considering the values of the LC50 obtained for each product. The LC50 and LC95 of the mixture were 0.019 (0.016 - 0.022) and 0.050 (0.040 - 0.065) mg/liter, respectively. The mixture combined both the larvicidal activity of spinosad and the juvenoid action of pyriproxyfen. From the LC70 to LC99 a significant synergism effect was observed between the two insecticides (CI ranged from 0.74 to 0.31). This strong synergism observed at high concentrations allows a reduction by five and nine-fold of pyriproxyfen and spinosad amounts to kill almost 100% mosquitoes. Combination of pyriproxyfen and spinosad may then represent a promising strategy to improve mosquito control in situations with insecticide-resistant Aedes dengue vectors.

  17. Gene expression and localization analysis of Bombyx mori bidensovirus and its putative receptor in B. mori midgut.

    PubMed

    Ito, Katsuhiko; Shimura, Sachiko; Katsuma, Susumu; Tsuda, Yasuhiro; Kobayashi, Jun; Tabunoki, Hiroko; Yokoyama, Takeshi; Shimada, Toru; Kadono-Okuda, Keiko

    2016-05-01

    Bombyx mori bidensovirus (BmBDV), which causes fatal flacherie disease in the silkworm, replicates only in midgut columnar cells. The viral resistance expressed by some silkworm strains, which is characterized as non-susceptibility irrespective of the viral dose, is determined by a single gene, nsd-2. We previously identified nsd-2 by positional cloning and found that this gene encodes a putative amino acid transporter that might function as a receptor for BmBDV. In this study, we investigated the relationship between the part of the midgut expressing nsd-2 (resistance gene), +(nsd-2) (susceptibility gene) and BmBDV propagation. Quantitative RT-PCR (qRT-PCR) analysis using total RNA isolated from the anterior, middle, and posterior parts of the midgut showed that nsd-2 and +(nsd-2) were strongly expressed in the posterior part of the midgut. The expression levels of both genes were very low in the anterior and middle parts. The qRT-PCR analysis showed that the expression levels of BmBDV-derived transcripts were correlated with the levels of +(nsd-2) expression. However, BmBDV-derived transcripts were clearly detected in all parts of the midgut. These results suggest that the infectivity of BmBDV depends mainly on the expression level of +(nsd-2) in the midgut and that viral infection is supported even by very faint expression of +(nsd-2). By contrast, the expression levels of +(nsd-2) were exceedingly low or undetectable in the middle part of the midgut, indicating that BmBDV infection might occur via another mechanism, independent of +(nsd-2), in the middle part of the midgut. PMID:26953258

  18. Anopheline Larval Habitats Seasonality and Species Distribution: A Prerequisite for Effective Targeted Larval Habitats Control Programmes

    PubMed Central

    Kweka, Eliningaya J.; Zhou, Guofa; Munga, Stephen; Lee, Ming-Chieh; Atieli, Harrysone E.; Nyindo, Mramba; Githeko, Andrew K.; Yan, Guiyun

    2012-01-01

    Background Larval control is of paramount importance in the reduction of malaria vector abundance and subsequent disease transmission reduction. Understanding larval habitat succession and its ecology in different land use managements and cropping systems can give an insight for effective larval source management practices. This study investigated larval habitat succession and ecological parameters which influence larval abundance in malaria epidemic prone areas of western Kenya. Methods and Findings A total of 51 aquatic habitats positive for anopheline larvae were surveyed and visited once a week for a period of 85 weeks in succession. Habitats were selected and identified. Mosquito larval species, physico-chemical parameters, habitat size, grass cover, crop cycle and distance to nearest house were recorded. Polymerase chain reaction revealed that An. gambiae s.l was the most dominant vector species comprised of An.gambiae s.s (77.60%) and An.arabiensis (18.34%), the remaining 4.06% had no amplification by polymerase chain reaction. Physico-chemical parameters and habitat size significantly influenced abundance of An. gambiae s.s (P = 0.024) and An. arabiensis (P = 0.002) larvae. Further, larval species abundance was influenced by crop cycle (P≤0.001), grass cover (P≤0.001), while distance to nearest houses significantly influenced the abundance of mosquito species larvae (r = 0.920;P≤0.001). The number of predator species influenced mosquito larval abundance in different habitat types. Crop weeding significantly influenced with the abundance of An.gambiae s.l (P≤0.001) when preceded with fertilizer application. Significantly higher anopheline larval abundance was recorded in habitats in pasture compared to farmland (P = 0.002). When habitat stability and habitat types were considered, hoof print were the most productive followed by disused goldmines. Conclusion These findings suggest that implementation of effective larval control

  19. Cytochromr b expression and RNAi knockdown in Aedes aegypti.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cytochrome b, coded by mitochondrial DNA, is one of the cytochromes involved in the electron transport in the respiratory chain of mitochondria. Cytochrome b is a critical intermediate in mitoptosis, i.e. a mitochondrial death pathway. To reveal whether cytochrome b of the mosquito Aedes aegypti (Ae...

  20. Pyrethroid resistance is widespread among Florida populations of Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aedes aegypti is an efficient vector of a number of diseases that affect man and is of increasing concern because of the reemergence of dengue and recent identification of locally acquired chikungunya in Florida. Pesticide resistance in this species has been demonstrated in several neighboring coun...

  1. USDA Research on New Strategies for Controlling Aedes aegypti.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    USDA researchers are currently studying new methods to control Aedes aegypti. One involves molecular pesticides which target critical genes/proteins (such as inhibitors of apoptosis proteins, IAPs) in mosquitoes using RNA interference (RNAi). RNAi constructs are evaluated in vivo in adult mosquito...

  2. Experimental Transmission of Mayaro Virus by Aedes aegypti

    PubMed Central

    Long, Kanya C.; Ziegler, Sarah A.; Thangamani, Saravanan; Hausser, Nicole L.; Kochel, Tadeusz J.; Higgs, Stephen; Tesh, Robert B.

    2011-01-01

    Outbreaks of Mayaro fever have been associated with a sylvatic cycle of Mayaro virus (MAYV) transmission in South America. To evaluate the potential for a common urban mosquito to transmit MAYV, laboratory vector competence studies were performed with Aedes aegypti from Iquitos, Peru. Oral infection in Ae. aegypti ranged from 0% (0/31) to 84% (31/37), with blood meal virus titers between 3.4 log10 and 7.3 log10 plaque-forming units (PFU)/mL. Transmission of MAYV by 70% (21/30) of infected mosquitoes was shown by saliva collection and exposure to suckling mice. Amount of viral RNA in febrile humans, determined by real-time polymerase chain reaction, ranged from 2.7 to 5.3 log10 PFU equivalents/mL. Oral susceptibility of Ae. aegypti to MAYV at titers encountered in viremic humans may limit opportunities to initiate an urban cycle; however, transmission of MAYV by Ae. aegypti shows the vector competence of this species and suggests potential for urban transmission. PMID:21976583

  3. A review on symmetries for certain Aedes aegypti models

    NASA Astrophysics Data System (ADS)

    Freire, Igor Leite; Torrisi, Mariano

    2015-04-01

    We summarize our results related with mathematical modeling of Aedes aegypti and its Lie symmetries. Moreover, some explicit, group-invariant solutions are also shown. Weak equivalence transformations of more general reaction diffusion systems are also considered. New classes of solutions are obtained.

  4. Integrated proteomic and transcriptomic analysis of the Aedes aegypti eggshell

    PubMed Central

    2014-01-01

    Background Mosquito eggshells show remarkable diversity in physical properties and structure consistent with adaptations to the wide variety of environments exploited by these insects. We applied proteomic, transcriptomic, and hybridization in situ techniques to identify gene products and pathways that participate in the assembly of the Aedes aegypti eggshell. Aedes aegypti population density is low during cold and dry seasons and increases immediately after rainfall. The survival of embryos through unfavorable periods is a key factor in the persistence of their populations. The work described here supports integrated vector control approaches that target eggshell formation and result in Ae. aegypti drought-intolerant phenotypes for public health initiatives directed to reduce mosquito-borne diseases. Results A total of 130 proteins were identified from the combined mass spectrometric analyses of eggshell preparations. Conclusions Classification of proteins according to their known and putative functions revealed the complexity of the eggshell structure. Three novel Ae. aegypti vitelline membrane proteins were discovered. Odorant-binding and cysteine-rich proteins that may be structural components of the eggshell were identified. Enzymes with peroxidase, laccase and phenoloxidase activities also were identified, and their likely involvements in cross-linking reactions that stabilize the eggshell structure are discussed. PMID:24707823

  5. Repellent activity of selected essential oils against Aedes aegypti.

    PubMed

    Choochote, W; Chaithong, U; Kamsuk, K; Jitpakdi, A; Tippawangkosol, P; Tuetun, B; Champakaew, D; Pitasawat, B

    2007-07-01

    Essential oils extracted from ten plant species were screened for repellency against Aedes aegypti mosquitoes. Three oils; Zanthoxylum piperitum, Anethum graveolens and Kaempferia galanga, exerted protection against A. aegypti, with median complete-protection times of 1, 0.5 and 0.25 h, respectively. The protection times were increased significantly by incorporating 10% vanillin. The highest potential was established from Z. piperitum oil +10% vanillin (2.5 h, range=1-2.5 h). Mixtures from pairs of the effective oils possessed slight repellency that ranged from 0-0.5 h. None of the oil combinations repelled A. aegypti for longer than their constituent oil alone. With vanillin added, however, each oil mixture provided improved protection, which was approximately equal to oil on its own. GC/MS analysis revealed that the main component of Z. piperitum fruit oil was limonene (37.99%), with minor amounts of sabinene (13.30%) and beta-myrcene (7.17%). Repellent testing of stored samples of Z. piperitum fruit oil against A. aegypti demonstrated that repellent activity of those kept at -20 degrees C or 4 degrees C was present for a period of at least 3 months. Therefore, the essential oil of Z. piperitum fruit may prove useful in the development of mosquito repellents as an effective personal protection measure against mosquito bites. PMID:17512681

  6. Experience- and age-mediated oviposition behaviour in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti).

    PubMed

    Ruktanonchai, N W; Lounibos, L P; Smith, D L; Allan, S A

    2015-09-01

    In repeated behaviours such as those of feeding and reproduction, past experiences can inform future behaviour. By altering their behaviour in response to environmental stimuli, insects in highly variable landscapes can tailor their behaviour to their particular environment. In particular, female mosquitoes may benefit from plasticity in their choice of egg-laying site as these sites are often temporally variable and clustered. The opportunity to adapt egg-laying behaviour to past experience also exists for mosquito populations as females typically lay eggs multiple times throughout their lives. Whether experience and age affect egg-laying (or oviposition) behaviour in the mosquito Stegomyia aegypti (=Aedes aegypti) (Diptera: Culicidae) was assessed using a wind tunnel. Initially, gravid mosquitoes were provided with a cup containing either repellent or well water. After ovipositing in these cups, the mosquitoes were blood-fed and introduced into a wind tunnel. In this wind tunnel, an oviposition cup containing repellent was placed in the immediate vicinity of the gravid mosquitoes. A cup containing well water was placed at the opposite end of the tunnel so that if the females flew across the chamber, they encountered the well water cup, in which they readily laid eggs. Mosquitoes previously exposed to repellent cups became significantly more likely to later lay eggs in repellent cups, suggesting that previous experience with suboptimal oviposition sites informs mosquitoes of the characteristics of nearby oviposition sites. These results provide further evidence that mosquitoes modify behaviour in response to environmental information and are demonstrated in a vector species in which behavioural plasticity may be ecologically and epidemiologically meaningful.

  7. Rapid biosynthesis of silver nanoparticles using Crotalaria verrucosa leaves against the dengue vector Aedes aegypti: what happens around? An analysis of dragonfly predatory behaviour after exposure at ultra-low doses.

    PubMed

    Murugan, Kadarkarai; Sanoopa, C P; Madhiyazhagan, Pari; Dinesh, Devakumar; Subramaniam, Jayapal; Panneerselvam, Chellasamy; Roni, Mathath; Suresh, Udaiyan; Nicoletti, Marcello; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Kumar, Suresh; Perumalsamy, Haribalan; Ahn, Young-Joon; Benelli, Giovanni

    2016-01-01

    Aedes aegypti is a primary vector of dengue, a mosquito-borne viral disease infecting 50-100 million people every year. Here, we biosynthesised mosquitocidal silver nanoparticles (AgNP) using the aqueous leaf extract of Crotalaria verrucosa. The green synthesis of AgNP was studied by UV-vis spectroscopy, SEM, EDX and FTIR. C. verrucosa-synthesised AgNPs were toxic against A. aegypti larvae and pupae. LC50 of AgNP ranged from 3.496 ppm (I instar larvae) to 17.700 ppm (pupae). Furthermore, we evaluated the predatory efficiency of dragonfly nymphs, Brachydiplax sobrina, against II and III instar larvae of A. aegypti in an aquatic environment contaminated with ultra-low doses of AgNP. Under standard laboratory conditions, predation after 24 h was 87.5% (II) and 54.7% (III). In an AgNP-contaminated environment, predation was 91 and 75.5%, respectively. Overall, C. verrucosa-synthesised AgNP could be employed at ultra-low doses to reduce larval population of dengue vectors enhancing predation rates of dragonfly nymphs. PMID:26284510

  8. Rapid biosynthesis of silver nanoparticles using Crotalaria verrucosa leaves against the dengue vector Aedes aegypti: what happens around? An analysis of dragonfly predatory behaviour after exposure at ultra-low doses.

    PubMed

    Murugan, Kadarkarai; Sanoopa, C P; Madhiyazhagan, Pari; Dinesh, Devakumar; Subramaniam, Jayapal; Panneerselvam, Chellasamy; Roni, Mathath; Suresh, Udaiyan; Nicoletti, Marcello; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Kumar, Suresh; Perumalsamy, Haribalan; Ahn, Young-Joon; Benelli, Giovanni

    2016-01-01

    Aedes aegypti is a primary vector of dengue, a mosquito-borne viral disease infecting 50-100 million people every year. Here, we biosynthesised mosquitocidal silver nanoparticles (AgNP) using the aqueous leaf extract of Crotalaria verrucosa. The green synthesis of AgNP was studied by UV-vis spectroscopy, SEM, EDX and FTIR. C. verrucosa-synthesised AgNPs were toxic against A. aegypti larvae and pupae. LC50 of AgNP ranged from 3.496 ppm (I instar larvae) to 17.700 ppm (pupae). Furthermore, we evaluated the predatory efficiency of dragonfly nymphs, Brachydiplax sobrina, against II and III instar larvae of A. aegypti in an aquatic environment contaminated with ultra-low doses of AgNP. Under standard laboratory conditions, predation after 24 h was 87.5% (II) and 54.7% (III). In an AgNP-contaminated environment, predation was 91 and 75.5%, respectively. Overall, C. verrucosa-synthesised AgNP could be employed at ultra-low doses to reduce larval population of dengue vectors enhancing predation rates of dragonfly nymphs.

  9. Chemical constituents and larvicidal potential of Feronia limonia leaf essential oil against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

    PubMed

    Senthilkumar, A; Jayaraman, M; Venkatesalu, V

    2013-03-01

    In the present investigation, the leaf essential oil of Feronia limonia was evaluated for chemical constituents and mosquito larvicidal activity against the larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. GC and GC-MS analyses revealed that the essential oil contain 51 compounds. Estragole (34.69 %) and β-pinene(23.59 %) were identified as the major constituents followed by methyl (Z)-caryophyllene (11.05 %), eugenol (6.50 %), linalool (3.97 %), phytol (3.27 %), sabinene (2.41 %) and limonene (2.27 %). Larval mortality was observed after 12 and 24 h of exposure period. The oil showed remarkable larvicidal activity against A. stephensi (LC(50) = 38.93 and LC(90) = 108.64 ppm (after 12 h); LC(50) = 15.03 and LC(90) = 36.69 ppm (after 24 h)), A. aegypti (LC(50) = 37.60 and LC(90) = 104.69 ppm (after 12 h); LC(50) = 11.59 and LC(90) = 42.95 ppm (after 24 h)) and C. quinquefasciatus (LC(50) = 52.08 and LC(90) = 124.33 ppm (after 12 h); LC(50) = 22.49 and LC(90) = 60.90 ppm (after 24 h)). Based on the results, the essential oil of F. limonia can be considered as a new source of larvicide for the control of vector mosquitoes.

  10. Mechanisms of Pyrethroid Resistance in the Dengue Mosquito Vector, Aedes aegypti: Target Site Insensitivity, Penetration, and Metabolism

    PubMed Central

    Kasai, Shinji; Komagata, Osamu; Itokawa, Kentaro; Shono, Toshio; Ng, Lee Ching; Kobayashi, Mutsuo; Tomita, Takashi

    2014-01-01

    Aedes aegypti is the major vector of yellow and dengue fevers. After 10 generations of adult selection, an A. aegypti strain (SP) developed 1650-fold resistance to permethrin, which is one of the most widely used pyrethroid insecticides for mosquito control. SP larvae also developed 8790-fold resistance following selection of the adults. Prior to the selections, the frequencies of V1016G and F1534C mutations in domains II and III, respectively, of voltage-sensitive sodium channel (Vssc, the target site of pyrethroid insecticide) were 0.44 and 0.56, respectively. In contrast, only G1016 alleles were present after two permethrin selections, indicating that G1016 can more contribute to the insensitivity of Vssc than C1534. In vivo metabolism studies showed that the SP strain excreted permethrin metabolites more rapidly than a susceptible SMK strain. Pretreatment with piperonyl butoxide caused strong inhibition of excretion of permethrin metabolites, suggesting that cytochrome P450 monooxygenases (P450s) play an important role in resistance development. In vitro metabolism studies also indicated an association of P450s with resistance. Microarray analysis showed that multiple P450 genes were over expressed during the larval and adult stages in the SP strain. Following quantitative real time PCR, we focused on two P450 isoforms, CYP9M6 and CYP6BB2. Transcription levels of these P450s were well correlated with the rate of permethrin excretion and they were certainly capable of detoxifying permethrin to 4′-HO-permethrin. Over expression of CYP9M6 was partially due to gene amplification. There was no significant difference in the rate of permethrin reduction from cuticle between SP and SMK strains. PMID:24945250

  11. The toxicity of a lipid transfer protein (Cc-LTP1) from Coffea canephora Seeds on the larval development of Callosobruchus maculatus (Coleoptera: Bruchidae).

    PubMed

    Zottich, Umberto; Da Cunha, Maura; Dias, Germana B; Rabelo, Guilherme R; Oliveira, Antonia Elenir A; Carvalho, André O; Fernandes, Kátia Valevski S; do Nascimento, Viviane V; Gomes, Valdirene M

    2014-10-01

    In this work, we analyzed the effects of coffee seed proteins, especially Cc-LTP1 on the larval development of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae), a bruchid pest of beans and the most important insect pest of Vigna unguiculata (L.) Walp. Artificial seed assay, which incorporated the F/0-90 fraction from Coffea canephora seeds, resulted in the reduction of oviposition and caused an inhibition of C. maculatus larval development in a dose-dependent manner. The F/0-90 fraction used at a 4 % concentration resulted in the survival of no larvae. The purified Cc-LTP1, at a concentration of 0.5 %, also demonstrated effective inhibition of larval development, reducing both females oviposition and the weight and number of larvae. Cc-LTP1 was also able to inhibit the C. maculatus gut α-amylase activity, and immunolabeling by an anti-LTP serum was observed in the midgut tissues of the C. maculatus larvae. Cc-LTP1 has shown binding affinity towards microvillar cells, endoplasmic reticulum and mitochondria, as demonstrated by micrographic images taken by a transmission electron microscope. The results from this study indicate that Cc-LTP1 has insecticidal actions toward C. maculatus and exerts anti-nutritional effects with direct actions on intestinal tissues.

  12. The toxicity of a lipid transfer protein (Cc-LTP1) from Coffea canephora Seeds on the larval development of Callosobruchus maculatus (Coleoptera: Bruchidae).

    PubMed

    Zottich, Umberto; Da Cunha, Maura; Dias, Germana B; Rabelo, Guilherme R; Oliveira, Antonia Elenir A; Carvalho, André O; Fernandes, Kátia Valevski S; do Nascimento, Viviane V; Gomes, Valdirene M

    2014-10-01

    In this work, we analyzed the effects of coffee seed proteins, especially Cc-LTP1 on the larval development of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae), a bruchid pest of beans and the most important insect pest of Vigna unguiculata (L.) Walp. Artificial seed assay, which incorporated the F/0-90 fraction from Coffea canephora seeds, resulted in the reduction of oviposition and caused an inhibition of C. maculatus larval development in a dose-dependent manner. The F/0-90 fraction used at a 4 % concentration resulted in the survival of no larvae. The purified Cc-LTP1, at a concentration of 0.5 %, also demonstrated effective inhibition of larval development, reducing both females oviposition and the weight and number of larvae. Cc-LTP1 was also able to inhibit the C. maculatus gut α-amylase activity, and immunolabeling by an anti-LTP serum was observed in the midgut tissues of the C. maculatus larvae. Cc-LTP1 has shown binding affinity towards microvillar cells, endoplasmic reticulum and mitochondria, as demonstrated by micrographic images taken by a transmission electron microscope. The results from this study indicate that Cc-LTP1 has insecticidal actions toward C. maculatus and exerts anti-nutritional effects with direct actions on intestinal tissues. PMID:25097041

  13. Rehydration of forensically important larval Diptera specimens.

    PubMed

    Sanford, Michelle R; Pechal, Jennifer L; Tomberlin, Jeffery K

    2011-01-01

    Established procedures for collecting and preserving evidence are essential for all forensic disciplines to be accepted in court and by the forensic community at large. Entomological evidence, such as Diptera larvae, are primarily preserved in ethanol, which can evaporate over time, resulting in the dehydration of specimens. In this study, methods used for rehydrating specimens were compared. The changes in larval specimens with respect to larval length and weight for three forensically important blow fly (Diptera: Calliphoridae) species in North America were quantified. Phormia regina (Meigen), Cochliomyia macellaria (F.), and Chrysomya rufifacies (Macquart) third-instar larvae were collected from various decomposing animals and preserved with three preservation methods (80% ethanol, 70% isopropyl alcohol, and hot-water kill then 80% ethanol). Preservative solutions were allowed to evaporate. Rehydration was attempted with either of the following: 80% ethanol, commercial trisodium phosphate substitute solution, or 0.5% trisodium phosphate solution. All three methods partially restored weight and length of specimens recorded before preservation. Analysis of variance results indicated that effects of preservation, rehydration treatment, and collection animal were different in each species. The interaction between preservative method and rehydration treatment had a significant effect on both P. regina and C. macellaria larval length and weight. In addition, there was a significant interaction effect of collection animal on larval C. macellaria measurements. No significant effect was observed in C. rufifacies larval length or weight among the preservatives or treatments. These methods could be used to establish a standard operating procedure for dealing with dehydrated larval specimens in forensic investigations.

  14. Fine-structural changes in the midgut of old Drosophila melanogaster

    NASA Technical Reports Server (NTRS)

    Anton-Erxleben, F.; Miquel, J.; Philpott, D. E.

    1983-01-01

    Senescent fine-structural changes in the midgut of Drosophila melanogaster are investigated. A large number of midgut mitochondria in old flies exhibit nodular cristae and a tubular system located perpendicular to the normal cristae orientation. Anterior intestinal cells show a senescent accumulation of age pigment, either with a surrounding two-unit membrane or without any membrane. The predominant localization of enlarged mitochondria and pigment in the luminal gut region may be related to the polarized metabolism of the intestinal cells. Findings concur with previous observations of dense-body accumulations and support the theory that mitochondria are involved in the aging of fixed post-mitotic cells. Demonstrated by statistical analyses is that mitochondrial size increase is related to mitochondrial variation increase.

  15. Molecular and phytochemical investigation of Angelica dahurica and Angelica pubescentis essential oils and their biological activity against Aedes aegypti, Stephanitis pyrioides, and Colletotrichum species.

    PubMed

    Tabanca, Nurhayat; Gao, Zengping; Demirci, Betul; Techen, Natascha; Wedge, David E; Ali, Abbas; Sampson, Blair J; Werle, Chris; Bernier, Ulrich R; Khan, Ikhlas A; Baser, Kemal Husnu Can

    2014-09-01

    In this study, Angelica dahurica and Angelica pubescentis root essential oils were investigated as pest management perspectives, and root samples were also analyzed genetically using the nuclear ribosomal internal transcribed spacer (ITS) region as a DNA barcode marker. A. pubescentis root essential oil demonstrated weak antifungal activity against Colletotrichum acutatum, Colletotrichum fragariae, and Colletotrichum gloeosporioides, whereas A. dahurica root essential oil did not show antifungal activity. Conversely, A. dahurica root essential oil demonstrated better biting deterrent and insecticidal activity against yellow fever mosquito, Aedes aegypti, and azalea lace bugs, Stephanitis pyrioides, than A. pubescentis root oil. The major compounds in the A. dahurica oil were found as α-pinene (46.3%), sabinene (9.3%), myrcene (5.5%), 1-dodecanol (5.2%), and terpinen-4-ol (4.9%). α-Pinene (37.6%), p-cymene (11.6%), limonene (8.7%), and cryptone (6.7%) were the major compounds found in the A. pubescentis oil. In mosquito bioassays, 1-dodecanol and 1-tridecanol showed antibiting deterrent activity similar to the positive control DEET (N,N-diethyl-3-methylbenzamide) at 25 nmol/cm(2) against Ae. aegypti, whereas only 1-tridecanol showed repellent activity in human-based cloth patch bioassay with minimum effective dosages (MED) of 0.086 ± 0.089 mg/cm(2) (DEET = 0.007 ± 0.003 mg/cm(2)). In larval bioassays, 1-tridecanol was more toxic with an LC50 value of 2.1 ppm than 1-dodecanol having an LC50 value of 5.2 ppm against 1-day-old Ae. aegypti larvae. 1-Dodecanol and 1-tridecanol could be useful for the natural mosquito control agents. PMID:25133520

  16. Aedes (Stegomyia) aegypti and Aedes (Howardina) cozumelensis in Yucatán State, México, with a summary of published collection records for Ae. cozumelensis.

    PubMed

    García-Rejón, Julián E; López-Uribe, Mildred P; Loroño-Pino, María Alba; Arana-Guardia, Roger; Puc-Tinal, Maria; López-Uribe, Genny M; Coba-Tún, Carlos; Baak-Baak, Carlos M; Machain-Williams, Carlos; Reyes-Solis, Guadalupe C; Lozano-Fuentes, Saul; Saavedra-Rodriguez, Karla; Black, William C; Beaty, Barry J; Eisen, Lars

    2012-12-01

    We collected mosquito immatures from artificial containers during 2010-2011 from 26 communities, ranging in size from small rural communities to large urban centers, located in different parts of Yucatán State in southeastern México. The arbovirus vector Aedes (Stegomyia) aegypti was collected from all 26 examined communities, and nine of the communities also yielded another container-inhabiting Aedes mosquito: Aedes (Howardina) cozumelensis. The communities from which Ae. cozumelensis were collected were all small rural communities (<6,000 inhabitants) in the north-central part of Yucatán State. These new collection records for Ae. cozumelensis demonstrate that this mosquito has a far broader geographic range in the Yucatán Peninsula than previously known. Ae. cozumelensis immatures were collected from both residential premises and cemeteries, with specimens recovered from rock holes as well as various artificial containers including metal cans, flower vases, buckets, tires, and a water storage tank. The co-occurrence with Ae. aegypti in small rural communities poses intriguing questions regarding linkages between these mosquitoes, including the potential for direct competition for larval development sites. Additional studies are needed to determine how commonly Ae. cozumelensis feeds on human blood and whether it is naturally infected with arboviruses or other pathogens of medical or veterinary importance. We also summarize the published records for Ae. cozumelensis, which are restricted to collections from México's Yucatán Peninsula and Belize, and uniformly represent geographic locations where Ae. aegypti can be expected to occur.

  17. Aedes (Stegomyia) aegypti and Aedes (Howardina) cozumelensis in Yucatán State, México, with a summary of published collection records for Ae. cozumelensis

    PubMed Central

    García-Rejón, Julián E.; López-Uribe, Mildred P.; Loroño-Pino, María Alba; Arana-Guardia, Roger; Puc-Tinal, Maria; López-Uribe, Genny M.; Coba-Tún, Carlos; Baak-Baak, Carlos M.; Machain-Williams, Carlos; Reyes-Solis, Guadalupe C.; Lozano-Fuentes, Saul; Saavedra-Rodriguez, Karla; Black IV, William C.; Beaty, Barry J.; Eisen, Lars

    2013-01-01

    We collected mosquito immatures from artificial containers during 2010–2011 from 26 communities, ranging in size from small rural communities to large urban centers, located in different parts of Yucatán State in southeastern México. The arbovirus vector Aedes (Stegomyia) aegypti was collected from all 26 examined communities, and nine of the communities also yielded another container-inhabiting Aedes mosquito: Aedes (Howardina) cozumelensis. The communities from which Ae. cozumelensis were collected were all small, rural communities (<6,000 inhabitants) in the north-central part of Yucatán State. These new collection records for Ae. cozumelensis demonstrate that this mosquito has a far broader geographic range in the Yucatán Peninsula than previously known. Ae. cozumelensis immatures were collected from both residential premises and cemeteries, with specimens recovered from rock holes as well as various artificial containers including metal cans, flower vases, buckets, tires and a water storage tank. The co-occurrence with Ae. aegypti in small rural communities poses intriguing questions regarding linkages between these mosquitoes, including the potential for direct competition for larval development sites. Additional studies are needed to determine how commonly Ae. cozumelensis feeds on human blood and whether it is naturally infected with arboviruses or other pathogens of medical or veterinary importance. We also summarize the published records for Ae. cozumelensis, which are restricted to collections from México’s Yucatán Peninsula and Belize, and uniformly represent geographic locations where Ae. aegypti can be expected to occur. PMID:23181861

  18. Molecular and phytochemical investigation of Angelica dahurica and Angelica pubescentis essential oils and their biological activity against Aedes aegypti, Stephanitis pyrioides, and Colletotrichum species.

    PubMed

    Tabanca, Nurhayat; Gao, Zengping; Demirci, Betul; Techen, Natascha; Wedge, David E; Ali, Abbas; Sampson, Blair J; Werle, Chris; Bernier, Ulrich R; Khan, Ikhlas A; Baser, Kemal Husnu Can

    2014-09-01

    In this study, Angelica dahurica and Angelica pubescentis root essential oils were investigated as pest management perspectives, and root samples were also analyzed genetically using the nuclear ribosomal internal transcribed spacer (ITS) region as a DNA barcode marker. A. pubescentis root essential oil demonstrated weak antifungal activity against Colletotrichum acutatum, Colletotrichum fragariae, and Colletotrich