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Mosquito Vector (mosquito + vector)
Selected AbstractsMalaria sporozoite antigen-directed genome-wide response in transgenic Drosophila,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 3 2009Jizhou Yan Abstract Malaria kills a million people annually. Understanding the relationship between a causative parasite, Plasmodium falciparum, and the mosquito vector might suggest novel prevention approaches. We created and transformed into Drosophila two genes encoding, thrombospondin-related adhesive protein (TRAP) and circumsporozoite protein (CSP), found on the cell surface of Plasmodium sporozoites. To understand a model insect's response, we induced these proteins separately and together, performing whole genome microarray analysis measuring gene expression changes. Gene ontology classification of responding genes reveals that TRAP and CSP strongly and differentially influence Drosophila genes involved with cell motility and gene regulation, respectively; however, the most striking effects are on the immune system. While immune-related genes are but modestly elevated compared with responses to sepsis, there is a marked repression of the Toll pathway. This suggests: (1) how Plasmodium infection of the mosquito might use TRAP and CSP to modulate the host insect's physiology to promote sporozoite survival and transmission to man and (2) that approaches to elevate expression of the mosquito's Toll pathway might lead to novel methods of malaria prevention. genesis 47:196,203, 2009. © 2009 Wiley-Liss, Inc. [source] Bacteriophage WO-B and Wolbachia in natural mosquito hosts: infection incidence, transmission mode and relative densityMOLECULAR ECOLOGY, Issue 9 2006N. CHAUVATCHARIN Abstract Bacteriophages of Wolbachia bacteria have been proposed as a potential transformation tool for genetically modifying mosquito vectors. In this study, we report the presence of the WO-B class of Wolbachia -associated phages among natural populations of several mosquito hosts. Eighty-eight percent (22/25) of Wolbachia -infected mosquito species surveyed were found to contain WO-B phages. WO-B phage orf7 sequence analysis suggested that a single strain of WO-B phage was found in most singly (23/24) or doubly (1/1) Wolbachia -infected mosquitoes. However, the single Wolbachia strain infecting Aedes perplexus was found to harbour at least two different WO-B phages. Phylogenetic analysis suggested that horizontal transmission of WO-B phages has occurred on an evolutionary scale between the Wolbachia residing in mosquitoes. On an ecological scale, a low trend of co-transmission occurred among specific WO-B phages within Wolbachia of each mosquito species. Assessment of the density of WO-B phage by real-time quantitative polymerase chain reaction (RTQ-PCR) revealed an average relative density of 7.76 × 105± 1.61 × 105 orf7 copies per individual mosquito for a single Wolbachia strain infecting mosquitoes, but a threefold higher density in the doubly Wolbachia-infected Aedes albopictus. However, the average combined density of WO-B phage(s) did not correlate with that of their Wolbachia hosts, which varied in different mosquito species. We also confirmed the presence of WO-B-like virus particles in the laboratory colony of Ae. albopictus (KLPP) morphologically, by transmission electron microscopy (TEM). The viral-like particles were detected after purification and filtration of Ae. albopictus ovary extract, suggesting that at least one WO-B-like phage is active (temperate) within the Wolbachia of this mosquito vector. Nevertheless, the idea of utilizing these bacteriophages as transformation vectors still needs more investigation and is likely to be unfeasible. [source] The structural and functional diversity of Hsp70 proteins from Plasmodium falciparumPROTEIN SCIENCE, Issue 9 2007Addmore Shonhai Abstract It is becoming increasingly apparent that heat shock proteins play an important role in the survival of Plasmodium falciparum against temperature changes associated with its passage from the cold-blooded mosquito vector to the warm-blooded human host. Interest in understanding the possible role of P. falciparum Hsp70s in the life cycle of the parasite has led to the identification of six HSP70 genes. Although most research attention has focused primarily on one of the cytosolic Hsp70s (PfHsp70-1) and its endoplasmic reticulum homolog (PfHsp70-2), further functional insights could be inferred from the structural motifs exhibited by the rest of the Hsp70 family members of P. falciparum. There is increasing evidence that suggests that PfHsp70-1 could play an important role in the life cycle of P. falciparum both as a chaperone and immunogen. In addition, P. falciparum Hsp70s and Hsp40 partners are implicated in the intracellular and extracellular trafficking of proteins. This review summarizes data emerging from studies on the chaperone role of P. falciparum Hsp70s, taking advantage of inferences gleaned from their structures and information on their cellular localization. The possible associations between P. falciparum Hsp70s with their cochaperone partners as well as other chaperones and proteins are discussed. [source] Motility and infectivity of Plasmodium berghei sporozoites expressing avian Plasmodium gallinaceum circumsporozoite proteinCELLULAR MICROBIOLOGY, Issue 5 2005Rita Tewari Summary Avian and rodent malaria sporozoites selectively invade different vertebrate cell types, namely macrophages and hepatocytes, and develop in distantly related vector species. To investigate the role of the circumsporozoite (CS) protein in determining parasite survival in different vector species and vertebrate host cell types, we replaced the endogenous CS protein gene of the rodent malaria parasite Plasmodium berghei with that of the avian parasite P. gallinaceum and control rodent parasite P. yoelii. In anopheline mosquitoes, P. berghei parasites carrying P. gallinaceum and rodent parasite P. yoelii CS protein gene developed into oocysts and sporozoites. Plasmodium gallinaceum CS expressing transgenic sporozoites, although motile, failed to invade mosquito salivary glands and to infect mice, which suggests that motility alone is not sufficient for invasion. Notably, a percentage of infected Anopheles stephensi mosquitoes showed melanotic encapsulation of late stage oocysts. This was not observed in control infections or in A. gambiae infections. These findings shed new light on the role of the CS protein in the interaction of the parasite with both the mosquito vector and the rodent host. [source] Molecular interactions between Plasmodium and its insect vectorsCELLULAR MICROBIOLOGY, Issue 11 2002R. E. Sinden Summary Our understanding of the intricate interactions between the malarial parasite and the mosquito vector is complicated both by the number and diversity of parasite and vector species, and by the experimental inaccessibility of phenomena under investigation. Steady developments in techniques to study the parasite in the mosquito have recently been augmented by methods to culture in their entirety the sporogonic stages of some parasite species. These, together with the new saturation technologies, and genetic transformation of both parasite and vector will permit penetrating studies into an exciting and largely unknown area of parasite,host interactions, an understanding of which must result in the development of new intervention strategies. This microreview highlights key areas of current basic molecular interest, and identifies numerous lacunae in our knowledge that must be filled if we are to make rational decisions for future control strategies. It will conclude by trying to explain why in the opinion of this reviewer understanding malaria,mosquito interactions may be critical to our future attempts to limit a disease of growing global importance. [source] Filariasis: diagnosis and treatmentDERMATOLOGIC THERAPY, Issue 6 2009Natalia Mendoza ABSTRACT Filariasis is an infectious disease of the lymphatics and subcutaneous tissues caused by nematodes or filariae. Carried by mosquito vectors, this disease causes millions of people to suffer from lymphedema and elephantiasis, characteristics of filariasis infection. This disease can be diagnosed through the identification of microfilariae in blood or skin samples, antigen detection, radiographic imaging, or polymerase chain reaction. Mass drug administration by the World Health Organization has helped to diminish the incidence of filariasis. However, continued research on new drugs and vaccinations will be needed to control and reduce the microfilarial levels in the human population. [source] Towards a fuller understanding of mosquito behaviour: use of electrocuting grids to compare the odour-orientated responses of Anopheles arabiensis and An. quadriannulatus in the fieldMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2008S. J. TORR Abstract The epidemiological role of and control options for any mosquito species depend on its degree of ,anthropophily'. However, the behavioural basis of this term is poorly understood. Accordingly, studies in Zimbabwe quantified the effects of natural odours from cattle and humans, and synthetic components of these odours, on the attraction, entry and landing responses of Anopheles arabiensis Giles (Diptera: Culicidae) and Anopheles quadriannulatus Theobald. The numbers of mosquitoes attracted to human or cattle odour were compared using electrocuting nets (E-nets), and entry responses were gauged by the catch from an odour-baited entry trap (OBET) relative to that from an odour-baited E-net. Landing responses were estimated by comparing the catches from E-nets and cloth targets covered with an electrocuting grid. For An. arabiensis, E-nets baited with odour from a single ox or a single man caught similar numbers, and increasing the dose of human odour from one to three men increased the catch four-fold. For An. quadriannulatus, catches from E-nets increased up to six-fold in the progression: man, three men, ox, and man + ox, with catch being correlated with bait mass. Entry responses of An. arabiensis were stronger with human odour (entry response 62%) than with ox odour (6%) or a mixture of cattle and human odours (15%). For An. quadriannulatus, the entry response was low (< 2%) with both cattle and human odour. Anopheles arabiensis did not exhibit a strong entry response to carbon dioxide (CO2) (0.2,2 L/min). The trends observed using OBETs and E-nets also applied to mosquitoes approaching and entering a hut. Catches from an electrocuting target baited with either CO2 or a blend of acetone, 1-octen-3-ol, 4-methylphenol and 3-n-propylphenol , components of natural ox odour , showed that virtually all mosquitoes arriving there alighted on it. The propensity of An. arabiensis to enter human habitation seemed to be mediated by odours other than CO2 alone. Characterizing ,anthropophily' by comparing the numbers of mosquitoes caught by traps baited with different host odours can lead to spurious conclusions; OBETs baited with human odour caught around two to four times more An. arabiensis than cattle-baited OBETs, whereas a human-baited E-net caught less (, 0.7) An. arabiensis than a cattle-baited E-net. Similar caution is warranted for other species of mosquito vectors. A fuller understanding of how to exploit mosquito behaviour for control and surveys requires wider approaches and more use of appropriate tools. [source] Bacteriophage WO-B and Wolbachia in natural mosquito hosts: infection incidence, transmission mode and relative densityMOLECULAR ECOLOGY, Issue 9 2006N. CHAUVATCHARIN Abstract Bacteriophages of Wolbachia bacteria have been proposed as a potential transformation tool for genetically modifying mosquito vectors. In this study, we report the presence of the WO-B class of Wolbachia -associated phages among natural populations of several mosquito hosts. Eighty-eight percent (22/25) of Wolbachia -infected mosquito species surveyed were found to contain WO-B phages. WO-B phage orf7 sequence analysis suggested that a single strain of WO-B phage was found in most singly (23/24) or doubly (1/1) Wolbachia -infected mosquitoes. However, the single Wolbachia strain infecting Aedes perplexus was found to harbour at least two different WO-B phages. Phylogenetic analysis suggested that horizontal transmission of WO-B phages has occurred on an evolutionary scale between the Wolbachia residing in mosquitoes. On an ecological scale, a low trend of co-transmission occurred among specific WO-B phages within Wolbachia of each mosquito species. Assessment of the density of WO-B phage by real-time quantitative polymerase chain reaction (RTQ-PCR) revealed an average relative density of 7.76 × 105± 1.61 × 105 orf7 copies per individual mosquito for a single Wolbachia strain infecting mosquitoes, but a threefold higher density in the doubly Wolbachia-infected Aedes albopictus. However, the average combined density of WO-B phage(s) did not correlate with that of their Wolbachia hosts, which varied in different mosquito species. We also confirmed the presence of WO-B-like virus particles in the laboratory colony of Ae. albopictus (KLPP) morphologically, by transmission electron microscopy (TEM). The viral-like particles were detected after purification and filtration of Ae. albopictus ovary extract, suggesting that at least one WO-B-like phage is active (temperate) within the Wolbachia of this mosquito vector. Nevertheless, the idea of utilizing these bacteriophages as transformation vectors still needs more investigation and is likely to be unfeasible. [source] Public safety aspects of pyrethroid insecticides used in West Nile virus-carrying mosquito control,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2007Derek W Gammon Abstract West Nile virus is becoming increasingly prevalent in the USA, causing fever, encephalitis, meningitis and many fatalities. Spread of the disease is reduced by controlling the mosquito vectors by a variety of means, including the use of pyrethroid insecticides, which are currently under scrutiny for potential carcinogenic effects in humans. Pyrethrins and resmethrin, a pyrethroid, have been shown to cause tumours in rat and mouse models respectively. However, the tumours appear to be caused by liver enzyme induction and hypertrophy rather than genotoxicity, and the results are therefore unlikely to be applicable to humans. Nonetheless, for resmethrin, the US Environmental Protection Agency (EPA) has concluded that there is a likely risk of carcinogenicity in humans, requiring the manufacturers to provide more detailed data to prove that it can be used safely in vector control. Reproductive toxicity of resmethrin in the rat is also discussed. Copyright © 2007 Society of Chemical Industry [source] | |||||||||||||