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1999
Lowenberger C A, Kamal S, Chiles J, Paskewitz S, Bulet Philippe, Hoffmann Jules A, Christensen B M
Mosquito-Plasmodium interactions in response to immune activation of the vector Journal Article
In: Exp. Parasitol., vol. 91, no. 1, pp. 59–69, 1999, ISSN: 0014-4894.
Abstract | Links | BibTeX | Tags: Aedes, Animals, Anopheles, Culicidae, Defensins, Digestive System, Escherichia coli, Female, Genetic, Hemolymph, hoffmann, Insect Vectors, M3i, messenger, Micrococcus luteus, Plasmodium, Plasmodium berghei, Plasmodium gallinaceum, Proteins, Reverse Transcriptase Polymerase Chain Reaction, RNA, Transcription
@article{lowenberger_mosquito-plasmodium_1999,
title = {Mosquito-Plasmodium interactions in response to immune activation of the vector},
author = {C A Lowenberger and S Kamal and J Chiles and S Paskewitz and Philippe Bulet and Jules A Hoffmann and B M Christensen},
doi = {10.1006/expr.1999.4350},
issn = {0014-4894},
year = {1999},
date = {1999-01-01},
journal = {Exp. Parasitol.},
volume = {91},
number = {1},
pages = {59--69},
abstract = {During the development of Plasmodium sp. within the mosquito midgut, the parasite undergoes a series of developmental changes. The elongated ookinete migrates through the layers of the midgut where it forms the oocyst under the basal lamina. We demonstrate here that if Aedes aegypti or Anopheles gambiae, normally susceptible to Plasmodium gallinaceum and P. berghei, respectively, are immune activated by the injection of bacteria into the hemocoel, and subsequently are fed on an infectious bloodmeal, there is a significant reduction in the prevalence and mean intensity of infection of oocysts on the midgut. Only those mosquitoes immune activated prior to, or immediately after, parasite ingestion exhibit this reduction in parasite development. Mosquitoes immune activated 2-5 days after bloodfeeding show no differences in parasite burdens compared with naive controls. Northern analyses reveal that transcriptional activity for mosquito defensins is not detected in the whole bodies of Ae. aegypti from 4 h to 10 days after ingesting P. gallinaceum, suggesting that parasite ingestion, passage from the food bolus through the midgut, oocyst formation, and subsequent release of sporozoites into the hemolymph do not induce the production of defensin. However, reverse transcriptase-PCR of RNA isolated solely from the midguts of Ae. aegypti indicates that transcription of mosquito defensins occurs in the midguts of naive mosquitoes and those ingesting an infectious or noninfectious bloodmeal. Bacteria-challenged Ae. aegypti showed high levels of mature defensin in the hemolymph that correlate with a lower prevalence and mean intensity of infection with oocysts. Because few oocysts were found on the midgut of immune-activated mosquitoes, the data suggest that some factor, induced by bacterial challenge, kills the parasite at a preoocyst stage.},
keywords = {Aedes, Animals, Anopheles, Culicidae, Defensins, Digestive System, Escherichia coli, Female, Genetic, Hemolymph, hoffmann, Insect Vectors, M3i, messenger, Micrococcus luteus, Plasmodium, Plasmodium berghei, Plasmodium gallinaceum, Proteins, Reverse Transcriptase Polymerase Chain Reaction, RNA, Transcription},
pubstate = {published},
tppubtype = {article}
}
During the development of Plasmodium sp. within the mosquito midgut, the parasite undergoes a series of developmental changes. The elongated ookinete migrates through the layers of the midgut where it forms the oocyst under the basal lamina. We demonstrate here that if Aedes aegypti or Anopheles gambiae, normally susceptible to Plasmodium gallinaceum and P. berghei, respectively, are immune activated by the injection of bacteria into the hemocoel, and subsequently are fed on an infectious bloodmeal, there is a significant reduction in the prevalence and mean intensity of infection of oocysts on the midgut. Only those mosquitoes immune activated prior to, or immediately after, parasite ingestion exhibit this reduction in parasite development. Mosquitoes immune activated 2-5 days after bloodfeeding show no differences in parasite burdens compared with naive controls. Northern analyses reveal that transcriptional activity for mosquito defensins is not detected in the whole bodies of Ae. aegypti from 4 h to 10 days after ingesting P. gallinaceum, suggesting that parasite ingestion, passage from the food bolus through the midgut, oocyst formation, and subsequent release of sporozoites into the hemolymph do not induce the production of defensin. However, reverse transcriptase-PCR of RNA isolated solely from the midguts of Ae. aegypti indicates that transcription of mosquito defensins occurs in the midguts of naive mosquitoes and those ingesting an infectious or noninfectious bloodmeal. Bacteria-challenged Ae. aegypti showed high levels of mature defensin in the hemolymph that correlate with a lower prevalence and mean intensity of infection with oocysts. Because few oocysts were found on the midgut of immune-activated mosquitoes, the data suggest that some factor, induced by bacterial challenge, kills the parasite at a preoocyst stage.
1998
Shahabuddin M, Fields I, Bulet Philippe, Hoffmann Jules A, Miller L H
Plasmodium gallinaceum: differential killing of some mosquito stages of the parasite by insect defensin Journal Article
In: Exp. Parasitol., vol. 89, no. 1, pp. 103–112, 1998, ISSN: 0014-4894.
Abstract | Links | BibTeX | Tags: Aedes, Animals, Anti-Infective Agents, Blood Proteins, Defensins, Diptera, hoffmann, Insect Vectors, insects, M3i, Plasmodium gallinaceum, Zygote
@article{shahabuddin_plasmodium_1998,
title = {Plasmodium gallinaceum: differential killing of some mosquito stages of the parasite by insect defensin},
author = {M Shahabuddin and I Fields and Philippe Bulet and Jules A Hoffmann and L H Miller},
doi = {10.1006/expr.1998.4212},
issn = {0014-4894},
year = {1998},
date = {1998-05-01},
journal = {Exp. Parasitol.},
volume = {89},
number = {1},
pages = {103--112},
abstract = {We examined several insect antimicrobial peptides to study their effect on Plasmodium gallinaceum zygotes, ookinetes, oocysts, and sporozoites. Only two insect defensins-Aeschna cyanea (dragon fly) and Phormia terranovae (flesh fly)-had a profound toxic effect on the oocysts in Aedes aegypti and on isolated sporozoites. The defensins affected the oocysts in a time-dependent manner. Injecting the peptide into the hemolymph 1 or 2 days after an infectious blood meal had no significant effect on prevalence of infection or relative oocyst density per mosquito. When injected 3 days after parasite ingestion, the relative oocyst density was significantly reduced. Injection on day 4 or later damaged the developing oocysts, although the oocysts density per mosquito was not significantly different when examined on day 8. The oocysts were swollen or had extensive internal vacuolization. The peptides had no detectable effect on the early stages of the parasite: the zygotes and ookinetes tested in vitro. Both the defensins were highly toxic to isolated sporozoites in vitro as indicated by disruption of the membrane permeability barrier, a change in morphology, and loss of motility. In contrast to the toxicity of cecropin and magainin for mosquitoes, defensin, at concentrations that kill parasites, is not toxic to mosquitoes, suggesting that defensin should be studied further as a potential molecule to block sporogonic development of Plasmodium.},
keywords = {Aedes, Animals, Anti-Infective Agents, Blood Proteins, Defensins, Diptera, hoffmann, Insect Vectors, insects, M3i, Plasmodium gallinaceum, Zygote},
pubstate = {published},
tppubtype = {article}
}
We examined several insect antimicrobial peptides to study their effect on Plasmodium gallinaceum zygotes, ookinetes, oocysts, and sporozoites. Only two insect defensins-Aeschna cyanea (dragon fly) and Phormia terranovae (flesh fly)-had a profound toxic effect on the oocysts in Aedes aegypti and on isolated sporozoites. The defensins affected the oocysts in a time-dependent manner. Injecting the peptide into the hemolymph 1 or 2 days after an infectious blood meal had no significant effect on prevalence of infection or relative oocyst density per mosquito. When injected 3 days after parasite ingestion, the relative oocyst density was significantly reduced. Injection on day 4 or later damaged the developing oocysts, although the oocysts density per mosquito was not significantly different when examined on day 8. The oocysts were swollen or had extensive internal vacuolization. The peptides had no detectable effect on the early stages of the parasite: the zygotes and ookinetes tested in vitro. Both the defensins were highly toxic to isolated sporozoites in vitro as indicated by disruption of the membrane permeability barrier, a change in morphology, and loss of motility. In contrast to the toxicity of cecropin and magainin for mosquitoes, defensin, at concentrations that kill parasites, is not toxic to mosquitoes, suggesting that defensin should be studied further as a potential molecule to block sporogonic development of Plasmodium.
