24 results on '"Whitten, Miranda M. A."'
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2. Molecular and Cellular Components of the Mating Machinery in Anopheles gambiae Females
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Rogers, David W., Whitten, Miranda M. A., Thailayil, Janis, Soichot, Julien, Levashina, Elena A., and Catteruccia, Flaminia
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- 2008
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3. Bacterial Competition Influences the Ability of Symbiotic Bacteria to Colonize Western Flower Thrips.
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Andongma, Awawing A., Whitten, Miranda M. A., Del Sol, Ricardo, Hitchings, Matthew, and Dyson, Paul J.
- Abstract
Symbiont mediated RNAi (SMR) is a promising method for precision control of pest insect species such as Western Flower Thrips (WFT). Two species of bacteria are known to be dominant symbiotic bacteria in WFT, namely BFo1 and BFo2 (Bacteria from Frankliniella occidentalis 1 and 2), as we here confirm by analysis of next-generation sequence data derived to obtain a reference WFT genome sequence. Our first demonstration of SMR in WFT used BFo2, related to Pantoea, isolated from a domesticated Dutch thrips population. However, for successful use of SMR as a thrips control measure, these bacteria need to successfully colonize different environmental thrips populations. Here, we describe a United Kingdom thrips population that does not harbour BFo2, but does contain BFo1, a species related to Erwinia. Attempts to introduce BFo2 indicate that this bacterium is unable to establish itself in the United Kingdom thrips, in contrast to successful colonization by a strain of BFo1 expressing green fluorescent protein. Fluorescence microscopy indicates that BFo1 occupies similar regions of the thrips posterior midgut and hindgut as BFo2. Bacterial competition assays revealed that a barrier to BFo2 establishing itself in thrips is the identity of the resident BFo1; BFo1 isolated from the United Kingdom thrips suppresses growth of BFo2 to a greater extent than BFo1 from the Dutch thrips that is permissive for BFo2 colonization. The ability of the latter strain of BFo1 to colonize the United Kingdom thrips is also likely attributable to its ability to out-compete the resident BFo1. Lastly, we observed that United Kingdom thrips pre-exposed to the Dutch BFo1 could then be successfully colonized by BFo2. These results indicate, for the first time, that microbial competition and strain differences can have a large influence on how symbiotic bacteria can colonize different populations of an insect species. [ABSTRACT FROM AUTHOR]
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- 2022
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4. Fungal infection dynamics in response to temperature in the lepidopteran insect Galleria mellonella.
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Kryukov, Vadim Y., Yaroslavtseva, Olga N., Whitten, Miranda M. A., Tyurin, Maksim V., Ficken, Katherine J., Greig, Carolyn, Melo, Nadja R., Glupov, Viktor V., Dubovskiy, Ivan M., and Butt, Tariq M.
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GREATER wax moth ,MYCOSES ,LEPIDOPTERA ,INSECTS ,ENTOMOPATHOGENIC fungi ,IMMUNE response - Abstract
This study examines how the dynamics of fungus-insect interactions can be modulated by temperature. The wax moth, Galleria mellonella, is a well-studied and important model insect whose larvae in the wild develop optimally at around 34 °C in beehives.However, surprisingly little research onwaxmoths has been conducted at relevant temperatures. In this study, the entomopathogenic fungus Metarhizium robertsii inflicted rapid and substantial mortality on wax moth larvae maintained at a constant temperature of 24 °C, but at 34 °C a 10 fold higher dose was required to achieve an equivalent mortality. The cooler temperature favored fungal pathogenicity, with condial adhesion to the cuticle, germination and hemocoel invasion all significantly enhanced at 24 °C, compared with 34 °C. Thewax moth larvae immune responses alteredwith the temperature, and with the infective dose of the fungus. Enzyme-based immune defenses (lysozyme and phenoloxidase) exhibited enhanced activity at the warmer temperature. A dramatic upregulation in the basal expression of galiomicin and gallerimycin was triggered by cooling, and thiswas augmented in the presence of the fungus. Profiling of the predominant insect epicuticular fatty acids revealed a 4-7 fold increase in palmetic, oleic and linoleic acids in larvae maintained at 24 °C compared with those at 34 °C, but these failed to exert fungistatic effects on topically applied fungus. This study demonstrates the importance of choosing environmental conditions relevant to the habitat of the insect host when determining the dynamics and outcome of insect/fungus interactions, and has particular significance for the application of entomopathogens as biocontrol agents. [ABSTRACT FROM AUTHOR]
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- 2018
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5. Re-evaluation of insect melanogenesis research: Views from the dark side.
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Whitten, Miranda M. A. and Coates, Christopher J.
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MELANOGENESIS , *BIOSYNTHESIS , *PHENOLS , *OXIDASES , *OXIDOREDUCTASES - Abstract
Melanins (eumelanin and pheomelanin) are synthesized in insects for several purposes including cuticle sclerotization and color patterning, clot formation, organogenesis, and innate immunity. Traditional views of insect immunity detail the storage of pro-phenoloxidases inside specialized blood cells (hemocytes) and their release upon recognition of foreign bodies. Activated phenoloxidases convert monophenols into reactive quinones in a two-step enzymatic reaction, and until recently, the mechanism of tyrosine hydroxylation remained a mystery. Herein, we present our interpretations of these enzyme-substrate complexes. The resultant melanins are deposited onto the surface of microbes to immobilize, agglutinate, and suffocate them. Phenoloxidase activity and melanin production are not limited to the blood (hemolymph) or cuticle, as recent evidence points to more diverse, sophisticated interactions in the gut and with the resident symbionts. This review offers insight into the somewhat neglected areas of insect melanogenesis research, particularly in innate immunity, its role in beneficial insects such as pollinators, the functional versatility of phenoloxidases, and the limitations of common experimental approaches that may impede progress inadvertently. [ABSTRACT FROM AUTHOR]
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- 2017
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6. Immuno-physiological adaptations confer wax moth Galleria mellonella resistance to Bacillus thuringiensis.
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Dubovskiy, Ivan M., Grizanova, Ekaterina V., Whitten, Miranda M. A., Mukherjee, Krishnendu, Greig, Carolyn, Alikina, Tatiana, Kabilov, Marsel, Vilcinskas, Andreas, Glupov, Viktor V., and Butt, Tariq M.
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GREATER wax moth ,BACILLUS thuringiensis ,INSECT evolution ,SURVIVAL behavior (Animals) ,INSECT genetics ,GENE expression - Abstract
Microevolutionary mechanisms of resistance to a bacterial pathogen were explored in a population of the Greater wax moth,Galleria mellonella, selected for an 8.8-fold increased resistance against the entomopathogenic bacteriumBacillus thuringiensis(Bt) compared with a non-selected (suspectible) line. Defense strategies of the resistant and susceptible insect lines were compared to uncover mechanisms underpinning resistance, and the possible cost of those survival strategies. In the uninfected state, resistant insects exhibited enhanced basal expression of genes related to regeneration and amelioration of Bt toxin activity in the midgut. In addition, these insects also exhibited elevated activity of genes linked to inflammation/stress management and immune defense in the fat body. Following oral infection with Bt, the expression of these genes was further elevated in the fat body and midgut of both lines and to a greater extent some of them in resistant line than the susceptible line. This gene expression analysis reveals a pattern of resistance mechanisms targeted to sites damaged by Bt with the insect placing greater emphasis on tissue repair as revealed by elevated expression of these genes in both the fat body and midgut epithelium. Unlike the susceptible insects, Bt infection significantly reduced the diversity and richness (abundance) of the gut microbiota in the resistant insects. These observations suggest that the resistant line not only has a more intact midgut but is secreting antimicrobial factors into the gut lumen which not only mitigate Bt activity but also affects the viability of other gut bacteria. Remarkably the resistant line employs multifactorial adaptations for resistance to Bt without any detected negative trade off since the insects exhibited higher fecundity. [ABSTRACT FROM PUBLISHER]
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- 2016
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7. Draft Genomes, Phylogenetic Reconstruction, and Comparative Genomics of Two Novel Cohabiting Bacterial Symbionts Isolated from Frankliniella occidentalis.
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Facey, Paul D., Méric, Guillaume, Hitchings, Matthew D., Pachebat, Justin A., Hegarty, Matt J., Chen, Xiaorui, Morgan, Laura V. A., Hoeppner, James E., Whitten, Miranda M. A., Kirk, William D. J., Dyson, Paul J., Sheppard, Sam K., and Sol, Ricardo Del
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GENOMES ,GENOMICS ,INVERTEBRATES ,FRANKLINIELLA occidentalis ,GENETICS - Abstract
Obligate bacterial symbionts are widespread in many invertebrates, where they are often confined to specialized host cells and are transmitted directly from mother to progeny. Increasing numbers of these bacteria are being characterized but questions remain about their population structure and evolution. Here we take a comparative genomics approach to investigate two prominent bacterial symbionts (BFo1 and BFo2) isolated from geographically separated populations of western flower thrips, Frankliniella occidentalis. Our multifaceted approach to classifying these symbionts includes concatenated multilocus sequence analysis (MLSA) phylogenies, ribosomal multilocus sequence typing (rMLST), construction of whole-genome phylogenies, and in-depth genomic comparisons. We showed that the BFo1 genome clusters more closely to species in the genus Erwinia, and is a putative close relative to Erwinia aphidicola. BFo1 is also likely to have shared a common ancestor with Erwiniapyrifoliae/Erwinia amylovora and the nonpathogenic Erwinia tasmaniensis and genetic traits similar to Erwinia billingiae. The BFo1 genome contained virulence factors found in the genus Erwinia but represented a divergent lineage. In contrast, we showed that BFo2 belongs within the Enterobacteriales but does not group closely with any currently known bacterial species. Concatenated MLSA phylogenies indicate that it may have shared a common ancestor to the Erwinia and Pantoea genera, and based on the clustering of rMLST genes, it was most closely relatedtoPantoea ananatis but represented adivergent lineage. We reconstructed a core genome of a putative common ancestor of Erwinia and Pantoea and compared this with the genomes of BFo bacteria. BFo2 possessed none of the virulence determinants that were omni present in the Erwinia and Pantoea genera. Taken together, these data are consistent with BFo2 representing a highly novel species that maybe related to known Pantoea. [ABSTRACT FROM AUTHOR]
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- 2015
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8. Cuticles of European and American lobsters harbor diverse bacterial species and differ in disease susceptibility.
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Whitten, Miranda M. A., Davies, Charlotte E., Kim, Anita, Tlusty, Michael, Wootton, Emma C., Chistoserdov, Andrei, and Rowley, Andrew F.
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- 2014
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9. Comparative Susceptibility of Different Biological Forms of Anopheles stephensi to Plasmodium berghei ANKA Strain.
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Basseri, Hamid R., Mohamadzadeh Hajipirloo, Habib, Mohammadi Bavani, Mulood, and Whitten, Miranda M. A.
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DISEASE susceptibility ,COMPARATIVE studies ,ANOPHELES stephensi ,PLASMODIUM berghei ,SPECIES diversity ,VACCINES ,PLASMODIUM ,HOST-parasite relationships - Abstract
Background: There are varying degrees of compatibility between malaria parasite-mosquito species, and understanding this compatibility may be crucial for developing effective transmission-blocking vaccines. This study investigates the compatibility of different biological forms of a malaria vector, Anopheles stephensi, to Plasmodium berghei ANKA strain. Methods: Several biologically different and allopatric forms of A. stephensi were studied. Three forms were isolated from different regions of southern Iran: the variety mysorensis, the intermediate form and the native type form, and an additional type form originated from India (Beech strain).The mosquitoes were experimentally infected with P. berghei to compare their susceptibility to parasitism. Anti-mosquito midgut antiserum was then raised in BALB/cs mice immunized against gut antigens from the most susceptible form of A. stephensi (Beech strain), and the efficacy of the antiserum was assessed in transmission-blocking assays conducted on the least susceptible mosquito biological form. Results: The susceptibility of different biological forms of A. stephensi mosquito to P. berghei was specifically inter-type varied. The Beech strain and the intermediate form were both highly susceptible to infection, with higher oocyst and sporozoite infection rates than intermediate and mysorensis forms. The oocyst infection, and particularly sporozite infection, was lowest in the mysorensis strain. Antiserum raised against midgut proteins of the Indian Beech type form blocked infection in this mosquito population, but it was ineffective at blocking both oocyst and sporozoite development in the permissive but geographically distant intermediate form mosquitoes. This suggests that a strong degree of incompatibility exists between the mosquito strains in terms of midgut protein(s) acting as putative ookinete receptors. Conclusions: The incompatibility in the midgut protein profiles between two biological forms of A. stephensi demonstrates a well-differentiated population structure according to geographical origin. Therefore, the design of potential transmission-blocking strategies should incorporate a more thorough understanding of intra-species variations in host-parasite interactions. [ABSTRACT FROM AUTHOR]
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- 2013
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10. Can Insects Develop Resistance to Insect Pathogenic Fungi?
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Dubovskiy, Ivan M., Whitten, Miranda M. A., Yaroslavtseva, Olga N., Greig, Carolyn, Kryukov, Vadim Y., Grizanova, Ekaterina V., Mukherjee, Krishnendu, Vilcinskas, Andreas, Glupov, Viktor V., and Butt, Tariq M.
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ENTOMOPATHOGENIC fungi , *INSECT development , *MYCOSES , *GREATER wax moth , *BEAUVERIA bassiana , *INSECT larvae , *IMMUNE response , *HOST-parasite relationships - Abstract
Microevolutionary adaptations and mechanisms of fungal pathogen resistance were explored in a melanic population of the Greater wax moth, Galleria mellonella. Under constant selective pressure from the insect pathogenic fungus Beauveria bassiana, 25th generation larvae exhibited significantly enhanced resistance, which was specific to this pathogen and not to another insect pathogenic fungus, Metarhizium anisopliae. Defense and stress management strategies of selected (resistant) and non-selected (susceptible) insect lines were compared to uncover mechanisms underpinning resistance, and the possible cost of those survival strategies. We hypothesize that the insects developed a transgenerationally primed resistance to the fungus B. bassiana, a costly trait that was achieved not by compromising life-history traits but rather by prioritizing and re-allocating pathogen-species-specific augmentations to integumental front-line defenses that are most likely to be encountered by invading fungi. Specifically during B. bassiana infection, systemic immune defenses are suppressed in favour of a more limited but targeted repertoire of enhanced responses in the cuticle and epidermis of the integument (e.g. expression of the fungal enzyme inhibitor IMPI, and cuticular phenoloxidase activity). A range of putative stress-management factors (e.g. antioxidants) is also activated during the specific response of selected insects to B. bassiana but not M. anisopliae. This too occurs primarily in the integument, and probably contributes to antifungal defense and/or helps ameliorate the damage inflicted by the fungus or the host’s own immune responses. [ABSTRACT FROM AUTHOR]
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- 2013
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11. The Major Yolk Protein Vitellogenin Interferes with the Anti-Plasmodium Response in the Malaria Mosquito Anopheles gambiae.
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Rono, Martin K., Whitten, Miranda M. A., Oulad-Abdelghani, Mustapha, Levashina, Elena A., and Marois, Eric
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ANOPHELES gambiae , *MOSQUITO genetics , *MALARIA , *PLASMODIUM , *VITELLOGENINS , *REPRODUCTION , *IMMUNITY - Abstract
When taking a blood meal on a person infected with malaria, female Anopheles gambiae mosquitoes, the major vector of human malaria, acquire nutrients that will activate egg development (oogenesis) in their ovaries. Simultaneously, they infect themselves with the malaria parasite. On traversing the mosquito midgut epithelium, invading Plasmodium ookinetes are met with a potent innate immune response predominantly controlled by mosquito blood cells. Whether the concomitant processes of mosquito reproduction and immunity affect each other remains controversial. Here, we show that proteins that deliver nutrients to maturing mosquito oocytes interfere with the antiparasitic response. Lipophorin (Lp) and vitellogenin (Vg), two nutrient transport proteins, reduce the parasite-killing efficiency of the antiparasitic factor TEP1. In the absence of either nutrient transport protein, TEP1 binding to the ookinete surface becomes more efficient. We also show that Lp is required for the normal expression of Vg, and for later Plasmodium development at the oocyst stage. Furthermore, our results uncover an inhibitory role of the Cactus/REL1/REL2 signaling cassette in the expression of Vg, but not of Lp. We reveal molecular links that connect reproduction and immunity at several levels and provide a molecular basis for a longsuspected trade-off between these two processes. [ABSTRACT FROM AUTHOR]
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- 2010
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12. Competency of Anopheles stephensi mysorensis strain for Plasmodium vivax and the role of inhibitory carbohydrates to block its sporogonic cycle.
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Basseri, Hamid R., Doosti, Soghra, Akbarzadeh, Kamran, Nateghpour, Mehdi, Whitten, Miranda M. A., and Ladoni, Hossein
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ANOPHELES ,PLASMODIUM vivax ,CARBOHYDRATES in the body ,MALARIA ,MOSQUITO vectors ,HOST-parasite relationships - Abstract
Background: Despite the abundance of studies conducted on the role of mosquitoes in malaria transmission, the biology and interaction of Plasmodium with its insect host still holds many mysteries. This paper provides the first study to follow the sporogonic cycle of Plasmodium vivax in a wild insecticide-resistant mysorensis strain of Anopheles stephensi, a major vector of vivax malaria in south-eastern Iran. The study subsequently demonstrates that host-parasite sugar binding interactions are critical to the development of this parasite in the salivary glands of its mosquito host. The identity of the receptors or sugars involved was revealed by a receptor "pre-saturation" strategy in which sugars fed to the mosquitoes inhibited normal host-parasite interactions. Methods: Anopheles stephensi mysorensis mosquitoes were artificially infected with P. vivax by feeding on the blood of gametocytaemic volunteers reporting to local malaria clinics in the Sistan-Baluchistan province of southeastern Iran. In order to determine the inhibitory effect of carbohydrates on sporogonic development, vector mosquitoes were allowed to ingest blood meals containing both gametocytes and added carbohydrates. The carbohydrates tested were GlcNAc, GalNAc, arabinose, fucose, mannose, lactose, glucose and galactose. Sporogonic development was assessed by survival of the parasite at both the oocyst and sporozoite stages. Results: Oocyst development was observed among nearly 6% of the fed control mosquitoes but the overall number of mosquitoes exhibiting sporozoite invasion of the salivary glands was 47.5% lower than the number supporting oocysts in their midgut. Of the tested carbohydrates, only arabinose and fucose slightly perturbed the development of P. vivax oocysts at the basal side of the mosquito midgut, and the remaining sugars caused no reductions in oocyst development. Strikingly however, sporozoites were completely absent from the salivary glands of mosquitoes treated with mannose, GalNAc, and lactose. Conclusion: The study indicates that An. stephensi in southern Iran has the potential to survive long enough to be re-infected and transmit vivax malaria several times, based on the average adult female longevity (about 30 days) and its gonotrophic cycle (2-3 days) during the malaria transmission season. Certain sugar binding interactions are important for the development of P. vivax sporozoites, and this information may be instrumental for the development of transmission blocking strategies. [ABSTRACT FROM AUTHOR]
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- 2008
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13. Fz2 and Cdc42 Mediate Melanization and Actin Polymerization but Are Dispensable for Plasmodium Killing in the Mosquito Midgut.
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Shin-Hong Shiao, Whitten, Miranda M. A., Zachary, Daniel, Hoffmann, Jules A., and Levashina, Elena A.
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ANOPHELES gambiae , *MOSQUITOES , *EPITHELIUM , *PLASMODIUM , *ACTIN , *POLYMERIZATION , *DOUBLE-stranded RNA , *TRANSMISSION electron microscopy - Abstract
The midgut epithelium of the mosquito malaria vector Anopheles is a hostile environment for Plasmodium, with most parasites succumbing to host defenses. This study addresses morphological and ultrastructural features associated with Plasmodium berghei ookinete invasion in Anopheles gambiae midguts to define the sites and possible mechanisms of parasite killing. We show by transmission electron microscopy and immunofluorescence that the majority of ookinetes are killed in the extracellular space. Dead or dying ookinetes are surrounded by a polymerized actin zone formed within the basal cytoplasm of adjacent host epithelial cells. In refractory strain mosquitoes, we found that formation of this zone is strongly linked to prophenoloxidase activation leading to melanization. Furthermore, we identify two factors controlling both phenomena: the transmembrane receptor frizzled-2 and the guanosine triphosphate-binding protein cell division cycle 42. However, the disruption of actin polymerization and melanization by double-stranded RNA inhibition did not affect ookinete survival. Our results separate the mechanisms of parasite killing from subsequent reactions manifested by actin polymerization and prophenoloxidase activation in the A. gambiae-P. berghei model. These latter processes are reminiscent of wound healing in other organisms, and we propose that they represent a form of wound-healing response directed towards a moribund ookinete, which is perceived as damaged tissue. [ABSTRACT FROM AUTHOR]
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- 2006
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14. Optimization of dietary RNA interference delivery to western flower thrips Frankliniella occidentalis and onion thrips Thrips tabaci.
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Andongma, Awawing A., Greig, Carolyn, Dyson, Paul J., Flynn, Natasha, and Whitten, Miranda M. A.
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- 2020
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15. Exploring the role of insect host factors in the dynamics of Trypanosoma cruzi–Rhodnius prolixus interactions
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Garcia, Eloi S., Ratcliffe, Norman A., Whitten, Miranda M., Gonzalez, Marcelo S., and Azambuja, Patricia
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TRYPANOSOMA cruzi , *CHAGAS' disease , *INSECTS , *CONENOSES , *ASSASSIN bugs - Abstract
Abstract: Members of the subfamily Triatominae, family Reduviidae, comprise a large number of insect species of which some are vectors of Trypanosoma cruzi, the causative agent of Chagas’ disease. This article outlines research on the process of transformation and the dynamics of developmental stages of Trypanosoma cruzi in the triatomine insect hosts. Special attention is given to the interactions of parasites with gut molecules, and the gut environment, and with host developmental physiology and intestinal organization. The vector insect''s permissiveness to Trypanosoma cruzi, which develops in the vector gut, largely depends on the host nutritional state, the parasite strain, trypanolytic compounds, digestive enzymes, lectins, resident bacteria in the gut and the endocrine system of the insect vector. Finally, the mechanisms of these interactions and their significance for Trypanosoma cruzi transmission are discussed. [Copyright &y& Elsevier]
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- 2007
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16. A narrow host-range and lack of persistence in two non-target insect species of a bacterial symbiont exploited to deliver insecticidal RNAi in Western Flower Thrips.
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Whitten MMA, Xue Q, Taning CNT, James R, Smagghe G, Del Sol R, Hitchings M, and Dyson P
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Introduction: Insecticidal RNAi is a targeted pest insect population control measure. The specificity of insecticidal RNAi can theoretically be enhanced by using symbiotic bacteria with a narrow host range to deliver RNAi, an approach termed symbiont-mediated RNAi (SMR), a technology we have previously demonstrated in the globally-invasive pest species Western Flower Thrips (WFT)., Methods: Here we examine distribution of the two predominant bacterial symbionts of WFT, BFo1 and BFo2, among genome-sequenced insects. Moreover, we have challenged two non-target insect species with both bacterial species, namely the pollinating European bumblebee, Bombus terrestris, and an insect predator of WFT, the pirate bug Orius laevigatus., Results: Our data indicate a very limited distribution of either symbiont among insects other than WFT. Moreover, whereas BFo1 could establish itself in both bees and pirate bugs, albeit with no significant effects on insect fitness, BFo2 was unable to persist in either species., Discussion: In terms of biosafety, these data, together with its more specific growth requirements, vindicate the choice of BFo2 for delivery of RNAi and precision pest management of WFT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Whitten, Xue, Taning, James, Smagghe, del Sol, Hitchings and Dyson.)
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- 2023
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17. Symbiont-Mediated RNA Interference (SMR): Using Symbiotic Bacteria as Vectors for Delivering RNAi to Insects.
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Dyson P, Figueiredo M, Andongma AA, and Whitten MMA
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- Animals, Bacteria genetics, RNA, Double-Stranded genetics, Thysanoptera genetics, Insecta genetics, RNA Interference
- Abstract
RNA interference (RNAi) has emerged as a widely used approach for reverse genetic analysis in eukaryotes. In insects, RNAi also has an application in the control of insect pests. Several methods have been developed for delivery of interfering RNA in insects, with varying outcomes for different species. Here we describe how a bacterial symbiont can be exploited for continuous synthesis of interfering double-stranded RNA (dsRNA) in its insect host. This approach, termed symbiont-mediated RNAi (SMR), can overcome problems associated with instability of dietary dsRNA due to action of salivary or foregut nucleases. As insects do not possess RNA-dependent RNA polymerase activity that can amplify and extend RNAi in other organisms, SMR also offers the possibility of long-term systemic RNAi not afforded by single applications of dsRNA to insects by other delivery methods. Here, we describe how SMR can be applied in a globally distributed agricultural pest species, western flower thrips (Frankliniella occidentalis)., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2022
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18. A novel bacterial infection of the edible crab, Cancer pagurus.
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Thrupp TJ, Whitten MM, and Rowley AF
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- Alphaproteobacteria physiology, Animals, Hemolymph microbiology, Host-Pathogen Interactions, Phagocytes microbiology, Phylogeny, RNA, Ribosomal, 16S chemistry, Sequence Analysis, RNA, Wales, Alphaproteobacteria genetics, Brachyura microbiology
- Abstract
There are few reports of bacterial diseases in crabs. A juvenile edible crab (Cancer pagurus) with a rickettsial-like infection was found in the intertidal zone at Freshwater East in South West Wales in July, 2012. Large numbers of bacteria-like particles were found in the haemolymph and within fixed phagocytes of the hepatopancreas. Molecular sequencing and subsequent phylogenetic analysis showed that the infectious agent was a member of the order Rhizobiales and therefore distinct to bacteria classified as rickettsia., (Copyright © 2015 Elsevier Inc. All rights reserved.)
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- 2016
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19. Disease profiles of juvenile edible crabs (Cancer pagurus L.) differ at two geographically-close intertidal sites.
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Thrupp TJ, Pope EC, Whitten MM, Bull JC, Wootton EC, Edwards M, Vogan CL, and Rowley AF
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- Aging, Animals, Disease, Prevalence, Wales, Brachyura, Shellfish
- Abstract
The prevalence of disease in edible crabs (Cancer pagurus) was assessed at two sites in South West Wales; one estuarine (Pembroke Ferry) and another facing open water (Freshwater East). Diseases included pink crab disease caused by Hematodinium sp., an infection of the antennal gland caused by Paramikrocytos canceri and an idiopathic inflammatory condition of the connective tissue surrounding the anterior ganglionic masses. This latter condition was only found in crabs from Pembroke Ferry. There was a significantly higher prevalence of pink crab disease at Freshwater East than Pembroke Ferry, although both sites had similar levels of infection by P. canceri., (Copyright © 2015 Elsevier Inc. All rights reserved.)
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- 2015
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20. A comparison of the structure of American (Homarus americanus) and European (Homarus gammarus) lobster cuticle with particular reference to shell disease susceptibility.
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Davies CE, Whitten MM, Kim A, Wootton EC, Maffeis TG, Tlusty M, Vogan CL, and Rowley AF
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- Animal Shells injuries, Animal Shells pathology, Animals, Europe, North America, Animal Shells microbiology, Nephropidae microbiology
- Abstract
The integument of arthropods is an important first-line defence against the invasion of parasites and pathogens. Once damaged, this can be subject to colonisation by microbial agents from the surrounding environment, which in crustaceans can lead to a condition termed shell disease syndrome. This condition has been reported in several crustacean species, including crabs and lobsters. The syndrome is a progressive condition where the outer cuticle becomes pitted and eroded, and in extreme cases is compromised, leaving animals susceptible to septicaemia. This study examined the susceptibility of juvenile American (Homarus americanus) and European (Homarus gammarus) lobsters to shell disease, as a result of mechanical damage. Scanning electron microscopy was used as a method to identify differences in the cuticle structure and consequences of mechanical damage. Claw regions were aseptically punctured, whilst carapaces were abraded using sterile sandpaper, to mimic natural damage. After a period of between 10 and 12 weeks, lobsters were sacrificed, fixed and stored for later examination. The carapace and claws of juvenile American lobsters were shown to be thinner and more vulnerable to abrasion damage than their European counterparts. In addition, the number and distribution of setal pits and pore canal openings also differed between the two species of lobster. Mechanical damage resulted in the formation of shell disease lesions on the claw and carapace of both lobster species. However, American lobsters, unlike their European counterparts, had extensive bacterial colonisation on the margins of these lesions. Overall, it is concluded that the cuticle of the American lobster is more susceptible to damage and resulting microbial colonisation. This may have implications for susceptibility of both species of lobster to shell disease syndrome., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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21. Comparative susceptibility of different biological forms of Anopheles stephensi to Plasmodium berghei ANKA strain.
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Basseri HR, Mohamadzadeh Hajipirloo H, Mohammadi Bavani M, and Whitten MM
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- Analysis of Variance, Animals, Enzyme-Linked Immunosorbent Assay, Host-Parasite Interactions, Immune Sera, Iran, Mice, Mice, Inbred BALB C, Species Specificity, Statistics, Nonparametric, Anopheles parasitology, Disease Transmission, Infectious, Plasmodium berghei genetics
- Abstract
Background: There are varying degrees of compatibility between malaria parasite-mosquito species, and understanding this compatibility may be crucial for developing effective transmission-blocking vaccines. This study investigates the compatibility of different biological forms of a malaria vector, Anopheles stephensi, to Plasmodium berghei ANKA strain., Methods: Several biologically different and allopatric forms of A. stephensi were studied. Three forms were isolated from different regions of southern Iran: the variety mysorensis, the intermediate form and the native type form, and an additional type form originated from India (Beech strain).The mosquitoes were experimentally infected with P. berghei to compare their susceptibility to parasitism. Anti-mosquito midgut antiserum was then raised in BALB/cs mice immunized against gut antigens from the most susceptible form of A. stephensi (Beech strain), and the efficacy of the antiserum was assessed in transmission-blocking assays conducted on the least susceptible mosquito biological form., Results: The susceptibility of different biological forms of A. stephensi mosquito to P. berghei was specifically inter-type varied. The Beech strain and the intermediate form were both highly susceptible to infection, with higher oocyst and sporozoite infection rates than intermediate and mysorensis forms. The oocyst infection, and particularly sporozite infection, was lowest in the mysorensis strain. Antiserum raised against midgut proteins of the Indian Beech type form blocked infection in this mosquito population, but it was ineffective at blocking both oocyst and sporozoite development in the permissive but geographically distant intermediate form mosquitoes. This suggests that a strong degree of incompatibility exists between the mosquito strains in terms of midgut protein(s) acting as putative ookinete receptors., Conclusions: The incompatibility in the midgut protein profiles between two biological forms of A. stephensi demonstrates a well-differentiated population structure according to geographical origin. Therefore, the design of potential transmission-blocking strategies should incorporate a more thorough understanding of intra-species variations in host-parasite interactions.
- Published
- 2013
- Full Text
- View/download PDF
22. Draft Genome Sequence of Rhodococcus rhodnii Strain LMG5362, a Symbiont of Rhodnius prolixus (Hemiptera, Reduviidae, Triatominae), the Principle Vector of Trypanosoma cruzi.
- Author
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Pachebat JA, van Keulen G, Whitten MM, Girdwood S, Del Sol R, Dyson PJ, and Facey PD
- Abstract
We report the 4,385,577-bp high-quality draft assembly of the bacterial symbiont Rhodococcus rhodnii strain LMG5362, isolated from the gut of Rhodnius prolixus (Hemiptera, Reduviidae, Triatominae), the principle vector of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. This sequence might provide useful information for subsequent studies of the symbiotic relationship between Rd. prolixus and Rc. rhodnii, while also providing a starting point for the development of biotechnological applications for the control of Rd. prolixus.
- Published
- 2013
- Full Text
- View/download PDF
23. Fz2 and cdc42 mediate melanization and actin polymerization but are dispensable for Plasmodium killing in the mosquito midgut.
- Author
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Shiao SH, Whitten MM, Zachary D, Hoffmann JA, and Levashina EA
- Subjects
- Animals, Anopheles immunology, Anopheles metabolism, Carrier Proteins genetics, Carrier Proteins metabolism, Frizzled Receptors genetics, Gastrointestinal Tract immunology, Gastrointestinal Tract ultrastructure, Host-Parasite Interactions, Immunity, Innate, Insect Vectors immunology, Insect Vectors parasitology, Intestinal Mucosa immunology, Intestinal Mucosa parasitology, Intestinal Mucosa ultrastructure, Microarray Analysis, Microscopy, Electron, Scanning, Plasmodium berghei ultrastructure, Polymers, RNA, Double-Stranded pharmacology, RNA, Protozoan pharmacology, Telomerase, cdc42 GTP-Binding Protein genetics, Actins metabolism, Anopheles parasitology, Frizzled Receptors metabolism, Gastrointestinal Tract parasitology, Melanins metabolism, Plasmodium berghei pathogenicity, cdc42 GTP-Binding Protein metabolism
- Abstract
The midgut epithelium of the mosquito malaria vector Anopheles is a hostile environment for Plasmodium, with most parasites succumbing to host defenses. This study addresses morphological and ultrastructural features associated with Plasmodium berghei ookinete invasion in Anopheles gambiae midguts to define the sites and possible mechanisms of parasite killing. We show by transmission electron microscopy and immunofluorescence that the majority of ookinetes are killed in the extracellular space. Dead or dying ookinetes are surrounded by a polymerized actin zone formed within the basal cytoplasm of adjacent host epithelial cells. In refractory strain mosquitoes, we found that formation of this zone is strongly linked to prophenoloxidase activation leading to melanization. Furthermore, we identify two factors controlling both phenomena: the transmembrane receptor frizzled-2 and the guanosine triphosphate-binding protein cell division cycle 42. However, the disruption of actin polymerization and melanization by double-stranded RNA inhibition did not affect ookinete survival. Our results separate the mechanisms of parasite killing from subsequent reactions manifested by actin polymerization and prophenoloxidase activation in the A. gambiae-P. berghei model. These latter processes are reminiscent of wound healing in other organisms, and we propose that they represent a form of wound-healing response directed towards a moribund ookinete, which is perceived as damaged tissue.
- Published
- 2006
- Full Text
- View/download PDF
24. A novel role for an insect apolipoprotein (apolipophorin III) in beta-1,3-glucan pattern recognition and cellular encapsulation reactions.
- Author
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Whitten MM, Tew IF, Lee BL, and Ratcliffe NA
- Subjects
- Amino Acid Sequence, Animals, Apolipoproteins metabolism, Apolipoproteins pharmacology, Cell Adhesion drug effects, Cell Adhesion immunology, Cell Movement drug effects, Cell Movement immunology, Dimyristoylphosphatidylcholine pharmacology, Hemocytes cytology, Hemocytes drug effects, Hemocytes immunology, Hemocytes microbiology, Hypocreales metabolism, Immunity, Innate, Insect Proteins metabolism, Insect Proteins pharmacology, Larva cytology, Larva immunology, Larva metabolism, Larva microbiology, Microspheres, Molecular Sequence Data, Moths metabolism, Moths microbiology, Protein Binding immunology, Spores, Fungal metabolism, Apolipoproteins physiology, Glucans metabolism, Insect Proteins physiology, Moths cytology, Moths immunology, beta-Glucans
- Abstract
Lipoproteins and molecules for pattern recognition are centrally important in the innate immune response of both vertebrates and invertebrates. Mammalian apolipoproteins such as apolipoprotein E (apoE) are involved in LPS detoxification, phagocytosis, and possibly pattern recognition. The multifunctional insect protein, apolipophorin III (apoLp-III), is homologous to apoE. In this study we describe novel roles for apoLp-III in pattern recognition and multicellular encapsulation reactions in the innate immune response, which may be of direct relevance to mammalian systems. It is known that apoLp-III stimulates antimicrobial peptide production in insect blood, enhances phagocytosis by insect blood cells (hemocytes), and binds and detoxifies LPS and lipoteichoic acid. In the present study we show that apoLp-III from the greater wax moth, Galleria mellonella, also binds to fungal conidia and beta-1,3-glucan and therefore may act as a pattern recognition molecule for multiple microbial and parasitic invaders. This protein also stimulates increases in cellular encapsulation of nonself particles by the blood cells and exerts shorter term, time-dependent, modulatory effects on cell attachment and spreading. All these responses are dose dependent, occur within physiological levels, and, with the notable exception of beta-glucan binding, are only observed with the lipid-associated form of apoLp-III. Preliminary studies also established a beneficial role for apoLp-III in the in vivo response to an entomopathogenic fungus. These data suggest a wide range of immune functions for a multiple specificity pattern recognition molecule and may provide a useful model for identifying further potential roles for homologous proteins in mammalian immunology, particularly in terms of fungal infections, pneumoconiosis, and granulomatous reactions.
- Published
- 2004
- Full Text
- View/download PDF
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