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anopheles gambiae males produce and transfer the vitellogenic steroid hormone 20-hydroxyecdysone to females during mating.in female insects, the steroid hormone 20-hydroxyecdysone (20e) plays a major role in activating vitellogenesis, a process required for egg development. by contrast with vertebrates, production of large amounts of hormonal steroids has not been reported in adult male insects. in the present study, we analyzed steroidogenesis in both male and female adult of the malaria mosquito anopheles gambiae and we found that a. gambiae male mosquitoes produce high amounts of the steroid hormone 20e. importa ...200819060216
the fatty acid biosynthesis enzyme fabi plays a key role in the development of liver-stage malarial parasites.the fatty acid synthesis type ii pathway has received considerable interest as a candidate therapeutic target in plasmodium falciparum asexual blood-stage infections. this apicoplast-resident pathway, distinct from the mammalian type i process, includes fabi. here, we report synthetic chemistry and transfection studies concluding that plasmodium fabi is not the target of the antimalarial activity of triclosan, an inhibitor of bacterial fabi. disruption of fabi in p. falciparum or the rodent para ...200819064257
exploring the mialome of ticks: an annotated catalogue of midgut transcripts from the hard tick, dermacentor variabilis (acari: ixodidae).ticks are obligate blood feeders. the midgut is the first major region of the body where blood and microbes ingested with the blood meal come in contact with the tick's internal tissues. little is known about protein expression in the digestive tract of ticks. in this study, for analysis of global gene expression during tick attachment and feeding, we generated and sequenced 1,679 random transcripts (ests) from cdna libraries from the midguts of female ticks at varying stages of feeding.200819021911
investigating the properties of bacillus thuringiensis cry proteins with novel loop replacements created using combinatorial molecular biology.cry proteins are a large family of crystalline toxins produced by bacillus thuringiensis. individually, the family members are highly specific, but collectively, they target a diverse range of insects and nematodes. domain ii of the toxins is important for target specificity, and three loops at its apex have been studied extensively. there is considerable interest in determining whether modifications in this region may lead to toxins with novel specificity or potency. in this work, we studied th ...200818408065
disruption of the plasmodium berghei 2-cys peroxiredoxin tpx-1 gene hinders the sporozoite development in the vector mosquito.to investigate the physiologic role of cytosolic 2-cys peroxiredoxin of plasmodium berghei (pbtpx-1), we infected the vector mosquito anopheles stephensi with a parasite carrying a targeted knockout of pbtpx-1 (prx-ko). the number of prx-ko midgut oocysts at 14-15 days post-feeding (pf) was comparable to that of the parent strain (wt); however, the numbers of sporozoites that formed in midgut oocysts and accumulated in the salivary gland of prx-ko-infected mosquitoes by 21 days pf were decreased ...200818417228
expression and processing of plasmodium berghei sera3 during liver stages.cysteine proteases mediate liberation of plasmodium berghei merozoites from infected hepatocytes. in an attempt to identify the responsible parasite proteases, we screened the genome of p. berghei for cysteine protease-encoding genes. rt-pcr analyses revealed that transcription of four out of five p. berghei serine repeat antigen (pbsera) genes was strongly upregulated in late liver stages briefly before the parasitophorous vacuole membrane ruptured to release merozoites into the host cell cytop ...200818419771
addition of cpg odn to recombinant pseudomonas aeruginosa exoprotein a conjugates of ama1 and pfs25 greatly increases the number of responders.both the blood-stage protein apical membrane antigen 1 (ama1) and the 25-kda sexual-stage protein (pfs25) of plasmodium falciparum are two leading candidates in malarial vaccine development. we have previously demonstrated that conjugation of these malarial antigens to recombinant pseudomonas aeruginosa exoprotein a (repa) significantly increased the mean-specific functional antibody responses in mice; however, some mice responded poorly and were unable to demonstrate a functional response. we h ...200818423804
ecological immunology of mosquito-malaria interactions.more than a century after the discovery of the complex life cycle of its causative agent, malaria remains a major health problem. understanding mosquito-malaria interactions could lead to breakthroughs in malaria control. novel strategies, such as the design of transgenic mosquitoes refractory to plasmodium, or design of human vaccines emulating mosquito resistance to the parasite, require extensive knowledge of processes involved in immune responses and of microevolutionary mechanisms that crea ...200818424235
critical role of a k+ channel in plasmodium berghei transmission revealed by targeted gene disruption.regulated k(+) transport across the plasma membrane is of vital importance for the survival of most cells. two k(+) channels have been identified in the plasmodium falciparum genome; however, their functional significance during parasite life cycle in the vertebrate host and during transmission through the mosquito vector remains unknown. we hypothesize that these two k(+) channels mediate the transport of k(+) in the parasites, and thus are important for parasite survival. to test this hypothes ...200818434537
functional characterization of a redundant plasmodium trap family invasin, trap-like protein, by aldolase binding and a genetic complementation test.efficient and specific host cell entry is of exquisite importance for intracellular pathogens. parasites of the phylum apicomplexa are highly motile and actively enter host cells. these functions are mediated by type i transmembrane invasins of the trap family that link an extracellular recognition event to the parasite actin-myosin motor machinery. we systematically tested potential parasite invasins for binding to the actin bridging molecule aldolase and complementation of the vital cytoplasmi ...200818441124
genome sequence surveys of brachiola algerae and edhazardia aedis reveal microsporidia with low gene densities.microsporidia are well known models of extreme nuclear genome reduction and compaction. the smallest microsporidian genomes have received the most attention, but genomes of different species range in size from 2.3 mb to 19.5 mb and the nature of the larger genomes remains unknown.200818445287
insulin signaling and foxo regulate the overwintering diapause of the mosquito culex pipiens.the short day lengths of late summer program the mosquito culex pipiens to enter a reproductive diapause characterized by an arrest in ovarian development and the sequestration of huge fat reserves. we suggest that insulin signaling and foxo (forkhead transcription factor), a downstream molecule in the insulin signaling pathway, mediate the diapause response. when we used rnai to knock down expression of the insulin receptor in nondiapausing mosquitoes (those reared under long day lengths) the p ...200818448677
targeted deletion of sap1 abolishes the expression of infectivity factors necessary for successful malaria parasite liver infection.malaria parasite sporozoites prepare for transmission to a mammalian host by upregulation of uis (upregulated in infectious sporozoites) genes. a number of uis gene products are essential for the establishment of the intrahepatocytic niche. however, the factors that regulate the expression of genes involved in gain of infectivity for the liver are unknown. herein, we show that a conserved plasmodium sporozoite low-complexity asparagine-rich protein, sap1 (sporozoite asparagine-rich protein 1), h ...200818466298
malaria and obesity: obese mice are resistant to cerebral malaria.the relationship between malaria and obesity are largely unknown. this is partly due to the fact that malaria occurs mainly in tropical areas where, until recently, obesity was not prevalent. it now appears, however, that obesity is emerging as a problem in developing countries. to investigate the possible role of obesity on the host-parasite response to malarial infection, this study applied a murine model, which uses the existence of genetically well characterized obese mice.200818489748
the microneme proteins ctrp and soap are not essential for plasmodium berghei ookinete to oocyst transformation in vitro in a cell free system.two plasmodium berghei ookinete micronemal proteins, circumsporozoite and trap related protein (ctrp) and secreted ookinete adhesive protein (soap) both interact with the basal lamina component laminin. following gene disruption studies it has been proposed that, apart from their role in motility, these proteins may be required for interactions leading to ookinete-to-oocyst transformation.200818489758
interactions between dendritic cells and cd4+ t cells during plasmodium infection.during infection, dendritic cells (dcs) encounter pathogenic microorganisms that can modulate their function and shape the t cell responses generated. during the process of t cell activation, dcs establish strong, long-lasting interactions with naïve t cells.200818495039
transmission blocking immunity in the malaria non-vector mosquito anopheles quadriannulatus species a.despite being phylogenetically very close to anopheles gambiae, the major mosquito vector of human malaria in africa, anopheles quadriannulatus is thought to be a non-vector. understanding the difference between vector and non-vector mosquitoes can facilitate development of novel malaria control strategies. we demonstrate that an. quadriannulatus is largely resistant to infections by the human parasite plasmodium falciparum, as well as by the rodent parasite plasmodium berghei. by using genetics ...200818497855
cloning, characterization, and expression of micrornas from the asian malaria mosquito, anopheles stephensi.micrornas (mirnas) are non-coding rnas that are now recognized as a major class of gene-regulating molecules widely distributed in metozoans and plants. mirnas have been found to play important roles in apoptosis, cancer, development, differentiation, inflammation, longevity, and viral infection. there are a few reports describing mirnas in the african malaria mosquito, anopheles gambiae, on the basis of similarity to known mirnas from other species. an. stephensi is the most important malaria v ...200818500992
west nile virus infection of drosophila melanogaster induces a protective rnai response.to determine if west nile virus (wnv) infection of insect cells induces a protective rnai response, drosophila melanogaster s2 and aedes albopictus c6/36 cells were infected with wnv, and the production of wnv-homologous small rnas was assayed as an indicator of rnai induction. a distinct population of approximately 25 nt wnv-homologous small rnas was detected in infected s2 cells but not c6/36 cells. rnai knockdown of argonaute 2 in s2 cells resulted in slightly increased susceptibility to wnv ...200818501400
gene-specific signatures of elevated non-synonymous substitution rates correlate poorly across the plasmodium genus.comparative genome analyses of parasites allow large scale investigation of selective pressures shaping their evolution. an acute limitation to such analysis of plasmodium falciparum is that there is only very partial low-coverage genome sequence of the most closely related species, the chimpanzee parasite p. reichenowi. however, if orthologous genes have been under similar selective pressures throughout the plasmodium genus then positive selection on the p. falciparum lineage might be predicted ...200818509456
the transmembrane isoform of plasmodium falciparum maebl is essential for the invasion of anopheles salivary glands.malaria transmission depends on infective stages in the mosquito salivary glands. plasmodium sporozoites that mature in midgut oocysts must traverse the hemocoel and invade the mosquito salivary glands in a process thought to be mediated by parasite ligands. maebl, a homologue of the transmembrane ebp ligands essential in merozoite invasion, is expressed abundantly in midgut sporozoites. alternative splicing generates different maebl isoforms and so it is unclear what form is functionally essent ...200818509478
gene silencing in phlebotomine sand flies: xanthine dehydrogenase knock down by dsrna microinjections.lutzomyia longipalpis are vectors of medically important visceral leishmaniasis in south america. blood-fed adult females digest large amounts of protein, and xanthine dehydrogenase is thought to be a key enzyme involved in protein catabolism through the production of urate. large amounts of heme are also released during digestion with potentially damaging consequences, as heme can generate oxygen radicals that damage lipids, proteins and nucleic acids. however, urate is an antioxidant that may ...200818510977
comparison of male reproductive success in malaria-refractory and susceptible strains of anopheles gambiae.in female mosquitoes that transmit malaria, the benefits of being refractory to the plasmodium parasite are balanced by the immunity costs in the absence of infection. male mosquitoes, however, gain no advantage from being refractory to blood-transmitted parasites, so that any costs associated with an enhanced immune system in the males limit the evolution of female refractoriness and has practical implications for the release of transgenic males.200818534029
a sporozoite asparagine-rich protein controls initiation of plasmodium liver stage development.plasmodium sporozoites invade host hepatocytes and develop as liver stages (ls) before the onset of erythrocytic infection and malaria symptoms. ls are clinically silent, and constitute ideal targets for causal prophylactic drugs and vaccines. the molecular and cellular mechanisms underlying ls development remain poorly characterized. here we describe a conserved plasmodium asparagine-rich protein that is specifically expressed in sporozoites and liver stages. gene disruption in plasmodium bergh ...200818551171
laboratory evaluation of 3 repellents against anopheles stephensi in the islamic republic of iran.this study evaluated the repellency effect of 3 topical repellents (permethrin, deet and neem tree extract) against 3-5 day old females of laboratory and field strains of anopheles stephensi. probing/biting rates on the shaved belly of white rabbits were counted. effective dose (ed) 50 and ed95 values were calculated by probit statistic software. the results revealed ed50 values of 0.007, 0.005 and 0.191 mg/cm2 for permethrin, deet and neem, respectively, against the field strain. the figures fo ...200818561716
proteomic analysis of zygote and ookinete stages of the avian malaria parasite plasmodium gallinaceum delineates the homologous proteomes of the lethal human malaria parasite plasmodium falciparum.delineation of the complement of proteins comprising the zygote and ookinete, the early developmental stages of plasmodium within the mosquito midgut, is fundamental to understand initial molecular parasite-vector interactions. the published proteome of plasmodium falciparum does not include analysis of the zygote/ookinete stages, nor does that of p. berghei include the zygote stage or secreted proteins. p. gallinaceum zygote, ookinete, and ookinete-secreted/released protein samples were prepare ...200818563747
novel peptide marker corresponding to salivary protein gsg6 potentially identifies exposure to anopheles bites.in order to improve malaria control, and under the aegis of who recommendations, many efforts are being devoted to developing new tools for identifying geographic areas with high risk of parasite transmission. evaluation of the human antibody response to arthropod salivary proteins could be an epidemiological indicator of exposure to vector bites, and therefore to risk of pathogen transmission. in the case of malaria, which is transmitted only by anopheline mosquitoes, maximal specificity could ...200818575604
depletion of plasmodium berghei plasmoredoxin reveals a non-essential role for life cycle progression of the malaria parasite.proliferation of the pathogenic plasmodium asexual blood stages in host erythrocytes requires an exquisite capacity to protect the malaria parasite against oxidative stress. this function is achieved by a complex antioxidant defence system composed of redox-active proteins and low mw antioxidants. here, we disrupted the p. berghei plasmoredoxin gene that encodes a parasite-specific 22 kda member of the thioredoxin superfamily. the successful generation of plasmoredoxin knockout mutants in the ro ...200818575607
rodent plasmodium: population dynamics of early sporogony within anopheles stephensi mosquitoes.early sporogony of plasmodium parasites involves 2 major developmental transitions within the insect vector, i.e., gametocyte-to-ookinete and ookinete-to-oocyst. this study compared the population dynamics of early sporogony among murine rodent plasmodium (plasmodium berghei, plasmodium chabaudi, plasmodium vinckei, and plasmodium yoelii) developing within anopheles stephensi mosquitoes. estimates of absolute densities were determined for gametocytes, ookinetes, and oocysts for 108 experimental ...200818576764
effect of washing on the bioefficacy of insecticide-treated nets (itns) and long-lasting insecticidal nets (llins) against main malaria vector anopheles stephensi by three bioassay methods.the use of pyrethoid impregnated bednets is one of the main malaria vector control strategies worldwide. the objective of the present study was to evaluate the bioefficacy of bednets impregnated with various pyrethroids after repeated washings.200818592843
chloroquine mediated modulation of anopheles gambiae gene expression.plasmodium development in the mosquito is crucial for malaria transmission and depends on the parasite's interaction with a variety of cell types and specific mosquito factors that have both positive and negative effects on infection. whereas the defensive response of the mosquito contributes to a decrease in parasite numbers during these stages, some components of the blood meal are known to favor infection, potentiating the risk of increased transmission. the presence of the antimalarial drug ...200818596975
plasmodium development in the mosquito: biology bottlenecks and opportunities for mathematical modeling.quantitative analyses of malaria parasite development are necessary to assess the efficacy of control measures. such analyses in the mammalian host have been difficult to implement, lagging behind the use of antiparasitic drugs, vaccine development and transmission-blocking strategies. even less is known about the genetic, environmental and other factors that impact sporogony in the mosquito host. here, we summarize current knowledge and review a first attempt to model sporogonic development qua ...200818603475
the aedes aegypti toll pathway controls dengue virus infection.aedes aegypti, the mosquito vector of dengue viruses, utilizes its innate immune system to ward off a variety of pathogens, some of which can cause disease in humans. to date, the features of insects' innate immune defenses against viruses have mainly been studied in the fruit fly drosophila melanogaster, which appears to utilize different immune pathways against different types of viruses, in addition to an rna interference-based defense system. we have used the recently released whole-genome s ...200818604274
phase 1 trial of malaria transmission blocking vaccine candidates pfs25 and pvs25 formulated with montanide isa 51.pfs25 and pvs25, surface proteins of mosquito stage of the malaria parasites p. falciparum and p. vivax, respectively, are leading candidates for vaccines preventing malaria transmission by mosquitoes. this single blinded, dose escalating, controlled phase 1 study assessed the safety and immunogenicity of recombinant pfs25 and pvs25 formulated with montanide isa 51, a water-in-oil emulsion.200818612426
evaluation of the function of a type i peritrophic matrix as a physical barrier for midgut epithelium invasion by mosquito-borne pathogens in aedes aegypti.in addition to modulating blood meal digestion and protecting the midgut epithelial cells from mechanical and chemical damage, a biological function attributed to the mosquito type i peritrophic matrix (pm) is preventing or reducing pathogen invasion, especially from plasmodium spp. previously, we demonstrated that chitin is an essential component of the pm and is synthesized de novo in response to blood feeding in aedes aegypti. therefore, knocking down chitin synthase expression by rna interfe ...200818627241
competency of anopheles stephensi mysorensis strain for plasmodium vivax and the role of inhibitory carbohydrates to block its sporogonic cycle.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 t ...200818627630
genistein-supplemented diet decreases malaria liver infection in mice and constitutes a potential prophylactic strategy.in tropical regions millions of people still live at risk of malaria infection. indeed the emergence of resistance to chloroquine and other drugs in use in these areas reinforces the need to implement alternative prophylactic strategies. genistein is a naturally occurring compound that is widely used as a food supplement and is thought to be effective in countering several pathologies. results presented here show that genistein inhibits liver infection by the plasmodium parasite, the causative a ...200818628947
imc1b is a putative membrane skeleton protein involved in cell shape, mechanical strength, motility, and infectivity of malaria ookinetes.membrane skeletons are cytoskeletal elements that have important roles in cell development, shape, and structural integrity. malaria parasites encode a conserved family of putative membrane skeleton proteins related to articulins. one member, imc1a, is expressed in sporozoites and localizes to the pellicle, a unique membrane complex believed to form a scaffold onto which the ligands and glideosome are arranged to mediate parasite motility and invasion. imc1b is a closely related structural paral ...200818650444
plasmodium yoelii sporozoites modulate cytokine profile and induce apoptosis in murine kupffer cells.plasmodium sporozoites traverse kupffer cells on their way into the liver. sporozoite contact does not elicit a respiratory burst in these hepatic macrophages and blocks the formation of reactive oxygen species in response to secondary stimuli via elevation of the intracellular camp concentration. here we show that increasing the camp level with dibutyryl cyclic adenosine monophosphate (db-camp) or isobutylmethylxanthine (ibmx) also modulates cytokine secretion in murine kupffer cells towards an ...200818656478
characterization of the multicopper oxidase gene family in anopheles gambiae.the multicopper oxidase (mco) family of enzymes includes laccases, which oxidize a broad range of substrates including diphenols, and several oxidases with specific substrates such as iron, copper or ascorbic acid. we have identified five putative mco genes in the genome of anopheles gambiae and have cloned cdnas encompassing the full coding region for each gene. mco1 mrna was detected in all developmental stages and in all of the larval and adult tissues tested. we observed an increase in mco1 ...200818675911
ethnobotanical study of some of mosquito repellent plants in north-eastern tanzania.the use of plant repellents against nuisance biting insects is common and its potential for malaria vector control requires evaluation in areas with different level of malaria endemicity. the essential oils of ocimum suave and ocimum kilimandscharicum were evaluated against malaria vectors in north-eastern tanzania.200818687119
temperature shift and host cell contact up-regulate sporozoite expression of plasmodium falciparum genes involved in hepatocyte infection.plasmodium sporozoites are deposited in the skin by anopheles mosquitoes. they then find their way to the liver, where they specifically invade hepatocytes in which they develop to yield merozoites infective to red blood cells. relatively little is known of the molecular interactions during these initial obligatory phases of the infection. recent data suggested that many of the inoculated sporozoites invade hepatocytes an hour or more after the infective bite. we hypothesised that this pre-invas ...200818688281
responses of anopheles gambiae, anopheles stephensi, aedes aegypti, and culex pipiens mosquitoes (diptera: culicidae) to cool and humid refugium conditions.like all terrestrial arthropods, mosquitoes must cope with the threat of desiccation. to gain insight into their survival strategies, we recorded the behavioral responses of anopheles gambiae, anopheles stephensi, aedes aegypti, and culex pipiens offered zones of different microclimatic conditions in laboratory cages. the cooled refugium was at 25.6 degrees c, 86% rh and the control was at 28.5 degrees c, 75% rh, i.e., a difference in saturation deficit of 3.9 mm hg between the two zones. we sho ...200818697317
efficacy of culture filtrates of metarhizium anisopliae against larvae of anopheles stephensi and culex quinquefasciatus.efficacy of culture filtrates of five strains of metarhizium anisopliae isolated from insects were evaluated against anopheles stephensi and culex quinquefasciatus. the culture filtrates released from the strains of m. anisopliae in the ypss and chitin broths were filtered and used for the bioassays after a growth of 7 days. among the culture filtrates of five strains, m. anisopliae 892 was found to be more effective against both the mosquitoes. the lc(50) values of culture filtrates of m. aniso ...200818709394
distinct malaria parasite sporozoites reveal transcriptional changes that cause differential tissue infection competence in the mosquito vector and mammalian host.the malaria parasite sporozoite transmission stage develops and differentiates within parasite oocysts on the anopheles mosquito midgut. successful inoculation of the parasite into a mammalian host is critically dependent on the sporozoite's ability to first infect the mosquito salivary glands. remarkable changes in tissue infection competence are observed as the sporozoites transit from the midgut oocysts to the salivary glands. our microarray analysis shows that compared to oocyst sporozoites, ...200818710954
establishment of a large semi-field system for experimental study of african malaria vector ecology and control in tanzania.medical entomologists increasingly recognize that the ability to make inferences between laboratory experiments of vector biology and epidemiological trends observed in the field is hindered by a conceptual and methodological gap occurring between these approaches which prevents hypothesis-driven empirical research from being conducted on relatively large and environmentally realistic scales. the development of semi-field systems (sfs) has been proposed as the best mechanism for bridging this ga ...200818715508
an insight into the salivary transcriptome and proteome of the soft tick and vector of epizootic bovine abortion, ornithodoros coriaceus.the salivary glands of blood-sucking arthropods contain a redundant 'magic potion' that counteracts their vertebrate host's hemostasis, inflammation, and immunity. we here describe the salivary transcriptome and proteomics (sialome) of the soft tick ornithodoros coriaceus. the resulting analysis helps to consolidate the classification of common proteins found in both soft and hard ticks, such as the lipocalins, kunitz, cystatin, basic tail, hebraein, defensin, til domain, metalloprotease, 5'-nuc ...200818725333
viral paratransgenesis in the malaria vector anopheles gambiae.paratransgenesis, the genetic manipulation of insect symbiotic microorganisms, is being considered as a potential method to control vector-borne diseases such as malaria. the feasibility of paratransgenic malaria control has been hampered by the lack of candidate symbiotic microorganisms for the major vector anopheles gambiae. in other systems, densonucleosis viruses (dnvs) are attractive agents for viral paratransgenesis because they infect important vector insects, can be genetically manipulat ...200818725926
cyanobacterial toxins as allelochemicals with potential applications as algaecides, herbicides and insecticides.cyanobacteria ("blue-green algae") from marine and freshwater habitats are known to produce a diverse array of toxic or otherwise bioactive metabolites. however, the functional role of the vast majority of these compounds, particularly in terms of the physiology and ecology of the cyanobacteria that produce them, remains largely unknown. a limited number of studies have suggested that some of the compounds may have ecological roles as allelochemicals, specifically including compounds that may in ...200818728763
attenuated plasmodium yoelii lacking purine nucleoside phosphorylase confer protective immunity.malaria continues to devastate sub-saharan africa owing to the emergence of drug resistance to established antimalarials and to the lack of an efficacious vaccine. plasmodium species have a unique streamlined purine pathway in which the dual specificity enzyme purine nucleoside phosphorylase (pnp) functions in both purine recycling and purine salvage. to evaluate the importance of pnp in an in vivo model of malaria, we disrupted pypnp, the gene encoding pnp in the lethal plasmodium yoelii ym str ...200818758447
reverse genetics screen identifies six proteins important for malaria development in the mosquito.transmission from the vertebrate host to the mosquito vector represents a major population bottleneck in the malaria life cycle that can successfully be targeted by intervention strategies. however, to date only about 25 parasite proteins expressed during this critical phase have been functionally analysed by gene disruption. we describe the first systematic, larger scale generation and phenotypic analysis of plasmodium berghei knockout (ko) lines, characterizing 20 genes encoding putatively sec ...200818761621
memory cd8 t cell responses exceeding a large but definable threshold provide long-term immunity to malaria.infection of mice with sporozoites of plasmodium berghei or plasmodium yoelii has been used extensively to evaluate liver-stage protection by candidate preerythrocytic malaria vaccines. unfortunately, repeated success of such vaccines in mice has not translated readily to effective malaria vaccines in humans. thus, mice may be used better as models to dissect basic parameters required for immunity to plasmodium-infection than as preclinical vaccine models. in turn, this basic information may aid ...200818780790
wash resistance of permanets in comparison to hand-treated nets.the wash resistance of factory produced permanets (with deltamethrin bonded to the netting with a resin) was studied by bioassays with anopheles stephensi. commercial detergent powders were used to wash the nets. for comparison, conventionally treated nets were washed and bio-assayed. nets were washed under laboratory conditions using a rotary shaker for 10min. mosquito bioassays used standard who plastic cones with an exposure time of 3min. the permanet caused almost a 100% mortality of an. ste ...200818053964
inhibition of collagen-induced platelet aggregation by anopheline antiplatelet protein, a saliva protein from a malaria vector mosquito.during blood feeding, mosquitoes inject saliva containing a mixture of molecules that inactivate or inhibit various components of the hemostatic response to the bite injury as well as the inflammatory reactions produced by the bite, to facilitate the ingestion of blood. however, the molecular functions of the individual saliva components remain largely unknown. here, we describe anopheline antiplatelet protein (aapp) isolated from the saliva of anopheles stephensi, a human malaria vector mosquit ...200818056842
low levels of mammalian tgf-beta1 are protective against malaria parasite infection, a paradox clarified in the mosquito host.nitric oxide (no), derived from catalysis of inducible no synthase (inos), limits malaria parasite growth in mammals. transforming growth factor (tgf)-beta1 suppresses inos in cells in vitro as well as in vivo in mice, but paradoxically severe malaria in humans is associated with low levels of tgf-beta1. we hypothesized that this paradox is a universal feature of infection and occurs in the mosquito anopheles stephensi, an invertebrate host for plasmodium that also regulates parasite development ...200817920060
plasmodium yoelii: correlation of up-regulated prophenoloxidase and phenoloxidases with melanization induced by the antimalarial, nitroquine.although knowledge of the mosquito immune response has recently improved, less is known about the impact of antimalarial drugs on mosquito immunity. in the present study, we found that nitroquine, an effective antimalaria drug, could also induce melanotic encapsulation of plasmodium by anopheles stephensi. the melanization rate of the nitroquine treated group was 60.8%. to explore the effect of nitroquine on mosquito immunity, we determined the increase in activity of phenoloxidases (po) enzyme, ...200817936755
exoerythrocytic development of plasmodium gallinaceum in the white leghorn chicken.plasmodium gallinaceum typically causes sub-clinical disease with low mortality in its primary host, the indian jungle fowl gallus sonnerati. domestic chickens of european origin, however, are highly susceptible to this avian malaria parasite. here we describe the development of p. gallinaceum in young white leghorn chicks with emphasis on the primary exoerythrocytic phase of the infection. using various regimens for infection, we found that p. gallinaceum induced a transient primary exoerythroc ...200818005972
vesicle trafficking during sporozoite development in plasmodium berghei: ultrastructural evidence for a novel trafficking mechanism.oocysts from anopheles stephensi mosquitoes fed on murine blood infected with plasmodium berghei berghei, were fixed for electron microscopy 6-12 days post-feeding. ultrastructural analysis focused on golgi-related trafficking pathways for rhoptry and microneme formation during sporogony. a small golgi complex of 1-3 cisternae is formed close to the spindle pole body from coated vesicles budded from the nuclear envelope which is confluent with the endoplasmic reticulum. rhoptries begin as small ...200817908361
flipping the paradigm on malaria transmission-blocking vaccines.the idea of malaria transmission-blocking vaccines (tbvs) surfaced more than two decades ago. since then, the research paradigm focused on developing tbvs that target surface antigens of parasite sexual stages. only recently has an effort emerged that flipped this paradigm, targeting antigens of the parasite's obligate invertebrate vector, the anopheles mosquito. here, we review the current state of knowledge of mosquito-based tbvs and discuss the utility of this approach for future vaccine deve ...200818599352
observations on sporozoite detection in naturally infected sibling species of the anopheles culicifacies complex and variant of anopheles stephensi in india.sporozoites were detected in naturally infected sibling species of the primary rural vector anopheles culicifacies complex in two primary health centres (phcs) and a variant of the urban vector anopheles stephensi in mangalore city, karnataka, south india while carrying out malaria outbreak investigations from 1998-2006. sibling species of an. culicifacies were identified based on the banding patterns on ovarian polytene chromosomes, and variants of an. stephensi were identified based on the num ...200819005232
characterization of mboi repeat dna sequence of anopheles stephensi.mboi repeat fragment of mosquito anopheles stephensi has been isolated by molecular cloning. the restriction map and entire nucleotide sequence of the 433bp insert has been determined. hybridization of this repeat dna with restriction enzyme digest of mosquito dna does not show an interspersed pattern but suggests that this repeat may be tandemly repeated at one major site and a few minor sites in the genome of anopheles stephensi. the hybridization pattern also indicates that this repeat family ...20081812089
larvicidal and ovicidal activity of cassia fistula linn. leaf extract against filarial and malarial vector mosquitoes.methanolic leaf extract of cassia fistula was tested for larvicidal and ovicidal activity against culex quinquefasciatus and anopheles stephensi. the extract was found to be more lethal to the larvae of a. stephensi than c. quinquefasciatus with lc(50) values of 17.97 and 20.57 mg/l, respectively. mean percent hatchability of the ovicidal activity was observed 120 h after treatment. the percent hatchability was inversely proportional to the concentration of extract and directly proportional to t ...200817989995
screening for antifeedant and larvicidal activity of plant extracts against helicoverpa armigera (hübner), sylepta derogata (f.) and anopheles stephensi (liston).plant extracts, especially botanical insecticides, are currently studied more and more because of the possibility of their use in plant protection. biological activity of five solvent plant extracts were studied using fourth instar larvae of gram pod borer helicoverpa armigera (lepidoptera: noctuidae), cotton leaf roller sylepta derogata (lepidoptera: pyralidae) and malaria vector anopheles stephensi (diptera: culicidae). antifeedant and larvicidal activity of acetone, chloroform, ethyl acetate, ...200818679716
morphological sexual dimorphism in three species of anopheline mosquito larvae.sexual separation at the larval stage in anopheline mosquitoes with the naked eye is difficult. we have identified distinguishing spots visible to the naked eye on the 6th abdominal segment of 3rd and 4th instars of anopheles stephensi, an. culicifacies, and an. subpictus. based on this feature, male and female larvae can be differentiated morphologically at 3rd and 4th instars of these species. this is the first report on these characteristic spots that may have a wide application for larval se ...200818666540
metabolic pathways in anopheles stephensi mitochondria.no studies have been performed on the mitochondria of malaria vector mosquitoes. this information would be valuable in understanding mosquito aging and detoxification of insecticides, two parameters that have a significant impact on malaria parasite transmission in endemic regions. in the present study, we report the analyses of respiration and oxidative phosphorylation in mitochondria of cultured cells [ase (anopheles stephensi mos. 43) cell line] from a. stephensi, a major vector of malaria in ...200818588503
studies on effect of acalypha indica l. (euphorbiaceae) leaf extracts on the malarial vector, anopheles stephensi liston (diptera:culicidae).the leaf extract of acalypha indica with different solvents viz, benzene, chloroform, ethyl acetate and methanol were tested for larvicidal, ovicidal activity and oviposition attractancy against anopheles stephensi. the larval mortality was observed after 24 h exposure. the lc(50) values are 19.25, 27.76, 23.26 and 15.03 ppm, respectively. mean percent hatchability of the ovicidal activity was observed 120 h after treatment. the percent hatchability was inversely proportional to the concentratio ...200818528709
parental guidance? trans-generational influences on offspring life history in mosquitoes.parental effects are important factors that might influence evolutionary and ecological aspects of parasite vectors and the parasites they transmit. a recent study demonstrated the importance of parental rearing conditions on the malaria vector anopheles stephensi. when parents are reared in a food-limited environment their offspring have increased bloodmeal sizes and larger clutches. the study highlights that ecological studies are vital for understanding vectors of disease and ultimately for d ...200818406210
mosquitocidal and repellent activity of the leaf extract of citrullus vulgaris (cucurbitaceae) against the malarial vector, anopheles stephensi liston (diptera culicidae).the efficacy of the cucurbitaceous plant citrullus vulgaris against the anopheles stephensi was assessed in the present study. the leaf extract of citrullus vulgaris with different solvents viz, benzene, petroleum ether, ethyl acetate and methanol were tested for larvicidial, ovicidal, repellent and insect growth regulatory activities against anopheles stephensi. the larval mortality was observed after 24 h exposure. the lc50 values are 18.56, 48.51, 49.57 and 50.32 ppm respectively. the mean pe ...200818401966
larvicidal and growth inhibition of the malaria vector anopheles stephensi by triterpenes from dysoxylum malabaricum and dysoxylum beddomei.secondary metabolites from dysoxylum malabaricum and dysoxylum beddomei were tested against mature and immature stage of the mosquito vector anopheles stephensi under laboratory conditions. the triterpenes 3beta,24,25-trihydroxycycloartane and beddomeilactone from d. malabaricum and d. beddomei showed strong larvicidal, pupicidal and adulticidal activity. they also affected the reproductive potential of adults by acting as oviposition deterrents. the highest concentration tested (10 ppm) of both ...200817869452
effect of synergist piperonyl butoxide (pbo) on the toxicity of some essential oils against mosquito larvae.effect of a known synergist piperonyl butoxide on the toxicity of steam distillate essential oils of jamarosa (cymbopogan nardus), pacholli (pogostemon pacholli), basil (ocimum basilicum), and peppermint (mentha pipreta) plant species against anopheles stephensi larvae were evaluated. the purpose of the present study was to identify the insecticidal potential of these oils against mosquito larvae. the piperonyl butoxide (pbo) was used to enhance the activity of these oils with the aim of develop ...200819579718
larvicidal activity of an indigenous plant, centratherum anthelminticum.crude extracts of fruits and leaves of centratherum anthelminticum in different solvents were tested for larvicidal activity against anopheles stephensi, the vector of malaria. the petroleum ether crude extract of both fruits and leaves exhibited significant larvicidal activity against iii instar larvae with lc50 values of 162.60 ppm and 522.94 ppm, respectively after 24 hr. the petroleum ether extract of fruit was 11.66, 2.15 and 1.32 times more toxic than that of leaf extract after 24, 48 and ...200819295062
gc-based analysis of insecticidal constituents of the flowers of azadirachta indica a. juss.the present article describes the analysis of an n-hexane soluble fraction of fresh flowers of azadirachta indica a. juss (neem), possessing larvicidal activity against anopheles stephensi liston, a vector of malarial parasite. forty-one compounds were identified in non-polar to less-polar fraction as well as in essential oil. these identifications were basically made through gc-eims. thus 5 sesquiterpenes, 3 aromatics, 17 fatty acids, 5 fatty acid esters, three steroids and 8 hydrocarbons were ...200919235028
larvicidal and oviposition activity of cassia obtusifolia linn (family: leguminosae) leaf extract against malarial vector, anopheles stephensi liston (diptera: culicidae).the ethanolic leaf extract of cassia obtusifolia was investigated for their larvicidal and oviposition deterrence effects against anopheles stephensi. concentrations ranging from 25 to 125 mg/l were assessed at 24 h post-treatment against late third instar larvae. the leaf extract had significant larvicidal effect with lc(50) and lc(90) values were 52.2 and 108.7 mg/l, respectively. in oviposition behaviour study, four different concentrations ranging from 100 to 400 mg/l were studied against gr ...200918818950
mediation of oviposition responses in the malaria mosquito anopheles stephensi liston by certain fatty acid esters.the chemical factors involved in oviposition site selection by mosquitoes have become the focus of interest in recent years, and considerable attention is paid to the chemical cues influencing mosquito oviposition. studies on synthetic oviposition attractants/repellents of long-chain fatty acid esters against anopheles stephensi are limited. screening and identification of chemicals which potentially attract/repel the gravid females to/or from oviposition site could be exploited for eco-friendly ...200918795330
the genetics of green thorax, a new larval colour mutant, non-linked with ruby - eye locus in the malaria mosquito, anopheles stephensi.anopheles stephensi, an important vector of malaria continues to be distributed widely in the indian subcontinent. the natural vigour of the species combined with its new tolerance, indeed resistance to insecticides has made it obligatory that we look for control methods involving genetic manipulation. hence, there is an immediate need for greater understanding of the genetics of this vector species. one of the requirements for such genetic studies is the establishment of naturally occurring mut ...200919502691
evaluation of the wash resistance of three types of manufactured insecticidal nets in comparison to conventionally treated nets.the present study evaluated the efficacy and wash resistance of several commercial deltamethrin-treated nets (permanet, from factory (pn-f) and market (pn-m), yorkool (y) and az net) that were claimed by the manufacturers to be long-lasting insecticide treated nets (llitns), compared to itns conventionally treated with deltamethrin (23-27 mg/m(2), using one k-o tab tablet (ko) per net). montpellier washing technique was used for washing the pieces of the nets. insecticidal activity was assessed ...200919442959
efficacy of aquatain, a monomolecular surface film, against the malaria vectors anopheles stephensi and an. gambiae s.s. in the laboratory.monomolecular films are used for mosquito control because of their asphyxiating effect on larvae and pupae. compared with other films, aquatain mosquito formulation (amf) has an improved spreading ability and flexibility on a water surface. in the laboratory, amf showed larvicidal, pupicidal, and oviposition deterrent effects against the malaria vectors anopheles stephensi and an. gambiae. at a dose of 1 ml/m(2), the median lethal time to death for late larval instars was 3.02 (95% confidence in ...200919407120
designing of a laboratory model for evaluation of the residual effects of deltamethrin (k-othrine wp 5%) on different surfaces against malaria vector, anopheles stephensi (diptera: culicidae).deltamethrin plays an important role in controlling malaria vectors, and is used in indoor residual spraying and manufacture of long-lasting insecticidal mosquito nets. the residual activity of deltamethrin (k-othrine wp 5%) @ 25 mg/m(2) was studied in laboratory conditions on different surfaces.200919959851
effect of synergist piperonyl butoxide (pbo) on the toxicity of some essential oils against mosquito larvae.effect of a known synergist piperonyl butoxide on the toxicity of steam distillate essential oils of jamarosa (cymbopogan nardus), pacholli (pogostemon pacholli), basil (ocimum basilicum), and peppermint (mentha pipreta) plant species against anopheles stephensi larvae were evaluated. the purpose of the present study was to identify the insecticidal potential of these oils against mosquito larvae. the piperonyl butoxide (pbo) was used to enhance the activity of these oils with the aim of develop ...200919886173
[effect of a growth inhibitor, oms 2017, on the fertility of anopheles stephensi liston, 1091 (diptera: culicidae].susceptibility of the anopheles stephensi in front of a growth inhibitory product, type ecdysoid, who 2017, under laboratory conditions, was detected. in addition, an inhibitory effect on fecundity was found after the exposition of initial fourth stage larvae in front of a dose of 0.001 mg/l.20092089505
homozygous chromosomal aberrations in anopheles stephensi.homozygotes for six autosomal paracentric inversions, an inserted paracentric inversion, an autosomal translocation, and two x-chromosome-chromosome 3 translocations in anopheles stephensi are described. three of these aberrations are being maintained in pure strains without the necessity of selection.20094040944
[a trial of breeding anopheles stephensi liston larvae]. 20091299763
[possible use of the color of the larval head capsule in the classification of malaria mosquitoes (anopheles, culicidae, diptera].the colour of the head capsule of larvae of three strains of anopheles stephensi is described. the data of earlier studies are summarized. it is concluded that it is possible and expedient to widely use of this sign in the systematization of anopheles.200911548318
analysis of insecticidal azadirachta indica a. juss. fractions.as a result of chemical investigation on the ethanolic extract of fresh fruit coatings of azadirachta indica a. juss. (neem), twenty-seven compounds were identified in non-polar to less polar fractions which showed pesticidal activity determined by who method against anopheles stephensi liston. these identifications were basically made through gc-eims and were further supported by other spectroscopic techniques, including 13c nmr, uv and ftir as well as retention indices. thus sixteen n-alkanes, ...200915018062
[recombinant plasmodium yoelii expressing green fluorescent protein in erythrocytic and mosquito stages].to generate recombinant plasmodium yoelii by265 strain which can express green fluorescent protein (gfp) in erythrocytic and mosquito stages.200920232630
an ovarian chromosome map of anopheles stephensi.a polytene chromosome map of anopheles stephensi has been prepared from the ovarian nurse cells of adult females. many homologous regions can be recognized in comparisons between the ovarian and salivary gland chromosome maps but band for band homologies are not readily evident. the preparation of polytene chromosomes from ovarian nurse cells is easier than from the larval salivary glands and the results more consistent.20094028836
the components of the daphnia pulex immune system as revealed by complete genome sequencing.branchiopod crustaceans in the genus daphnia are key model organisms for investigating interactions between genes and the environment. one major theme of research on daphnia species has been the evolution of resistance to pathogens and parasites, but lack of knowledge of the daphnia immune system has limited the study of immune responses. here we provide a survey of the immune-related genome of d. pulex, derived from the newly completed genome sequence. genes likely to be involved in innate immu ...200919386092
loop-mediated isothermal amplification (lamp) for rapid identification of anopheles gambiae and anopheles arabiensis mosquitoes.the main malaria vectors of sub-saharan africa, anopheles gambiae sensu stricto and anopheles arabiensis are morphologically indistinguishable, but often occur in sympatry and differ in feeding preference and vector competence. it is important to assess vector species identity for understanding the vectorial system and establishing appropriate vector control measures. the currently available species diagnosis methods for an. gambiae sensu latu require equipment to which public health practitione ...200919996433
infection of the malaria mosquito, anopheles gambiae, with two species of entomopathogenic fungi: effects of concentration, co-formulation, exposure time and persistence.entomopathogenic fungi metarhizium anisopliae and beauveria bassiana isolates have been shown to infect and reduce the survival of mosquito vectors.200920030834
larvicidal activity of artemisia annua l. callus culture against anopheles stephensi larvae.the emergence of resistance by both plasmodium falciparum and anopheles stephensi made the search for an alternative environmentally safe plant based insecticide inevitable. artemisia annua is a well known antimalarial. present study is an attempt to induce callus production from young leaves of artemisia annua plant and study its larvicidal activity against larvae of anopheles stephensi. callus was initiated by using different concentrations of auxins and cytokinins. a suitable culture media wa ...200920120465
efficacy of bacillus thuringiensis var. kurstaki in the control of two mosquito species (anopheles stephensi and culex quinquefasciatus).bioinsecticide bacillus thuringiensis var. kurstaki (btk) was used for controlling the mosquito species (anopheles stephensi and culex quinquefasciatus) which gave a significant (p<0.05) mortality in both species. the higher concentration of btk was highly effective compared to the control ones. the controlling effect was dose and time dependent. among the studied mosquitoes the c. quinquefasciatus (lc5 0.154%) was more susceptible than a. stephensi (lc50 0.372%) towards the bioinsecticide btk.200920120473
evaluation of larvicidal efficacy of solanum xanthocarpum storage against vector mosquitoes in north - western rajasthan.efficacy of the methanol extracts from fruits without seeds, whole yellow ripe fruits and seeds of the plant solanum xanthocarpum was evaluated against larvae of anopheles culicifacies, anopheles stephensi, aedes aegypti and culex quinquefasciatus, the important vector mosquitoes prevalent in the arid region. experiments were carried out on late 3rd or early 4th instar larvae of these mosquitoes using standard who technique. 24 and 48 hr lc50 and lc90 values along with their fiducial limits, reg ...200920143723
larvicidal and adulticidal activities of some medicinal plants against the malarial vector, anopheles stephensi (liston).the present study was undertaken to test the efficacy of 11 commonly available medicinal plants and compare its efficacy in relation to larvicidal and mosquitocidal activities against larvae and adults of anopheles stephensi (liston). all the medicinal plants and the mixture were effective against larvae of a. stephensi as evidenced by low lethal concentration and lethal time. the lethality varied in adults and plant extracts of mixture; eucalyptus globulus, cymbopogan citratus, artemisia annua, ...200918787842
transmission of different strains of plasmodium cynomolgi to aotus nancymaae monkeys and relapse.forty-four splenectomized aotus nancymaae monkeys were infected with 6 different strains of plasmodium cynomolgi, 11 via trophozoites and 33 via sporozoites. sporozoites from anopheles dirus, anopheles freeborni, anopheles gambiae, anopheles maculatus, and anopheles stephensi resulted in prepatent periods ranging from 9 to 39 days (median of 15 days). importantly, relapse was demonstrated in 5 of 5 sporozoite-induced infections with the rossan strain following treatment with chloroquine.200918788885
hiv protease inhibitors inhibit the development of preerythrocytic-stage plasmodium parasites.recent studies have demonstrated that human immunodeficiency virus (hiv) protease inhibitors (pis) exert inhibitory effects on erythrocytic stages of the human-malaria parasite plasmodium falciparum in vitro and on erythrocytic stages of the rodent-malaria parasite plasmodium chabaudi in vivo. although it remains unclear how hiv pis inhibit the parasite, the effect seen on parasite development in the erythrocytic stages is potent. the effect on preerythrocytic stages has not yet been investigate ...200919032102
enhanced immunogenicity of plasmodium falciparum peptide vaccines using a topical adjuvant containing a potent synthetic toll-like receptor 7 agonist, imiquimod.plasmodium sporozoites injected into the skin by malaria-infected mosquitoes can be effectively targeted by antibodies that block parasite invasion of host hepatocytes and thus prevent the subsequent development of blood stage infections responsible for clinical disease. malaria subunit vaccines require potent adjuvants, as they lack known pathogen-associated molecular patterns found in attenuated viral or bacterial vaccines that function as toll-like receptor (tlr) agonists to stimulate dendrit ...200919047411
a role for immune responses against non-cs components in the cross-species protection induced by immunization with irradiated malaria sporozoites.immunization with irradiated plasmodium sporozoites induces sterile immunity in rodents, monkeys and humans. the major surface component of the sporozoite the circumsporozoite protein (cs) long considered as the antigen predominantly responsible for this immunity, thus remains the leading candidate antigen for vaccines targeting the parasite's pre-erythrocytic (pe) stages. however, this role for cs was questioned when we recently showed that immunization with irradiated sporozoites (irrspz) of a ...200919890387
a nonadjuvanted polypeptide nanoparticle vaccine confers long-lasting protection against rodent malaria.we have designed and produced a prototypic malaria vaccine based on a highly versatile self-assembling polypeptide nanoparticle (sapn) platform that can repetitively display antigenic epitopes. we used this platform to display a tandem repeat of the b cell immunodominant repeat epitope (dppppnpn)(2)d of the malaria parasite plasmodium berghei circumsporozoite protein. administered in saline, without the need for a heterologous adjuvant, the sapn construct p4c-mal conferred a long-lived, protecti ...200919915055
transgenic technologies to induce sterility.the last few years have witnessed a considerable expansion in the number of tools available to perform molecular and genetic studies on the genome of anopheles mosquitoes, the vectors of human malaria. as a consequence, knowledge of aspects of the biology of mosquitoes, such as immunity, reproduction and behaviour, that are relevant to their ability to transmit disease is rapidly increasing, and could be translated into concrete benefits for malaria control strategies. amongst the most important ...200919917077
male mating biology.before sterile mass-reared mosquitoes are released in an attempt to control local populations, many facets of male mating biology need to be elucidated. large knowledge gaps exist in how both sexes meet in space and time, the correlation of male size and mating success and in which arenas matings are successful. previous failures in mosquito sterile insect technique (sit) projects have been linked to poor knowledge of local mating behaviours or the selection of deleterious phenotypes during colo ...200919917078
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