a-blood-free-diet-to-rear-anopheline-mosquitoes

A Blood-Free Diet to Rear Anopheline Mosquitoes

Malaria research requires large-scale breeding and production conditions for mosquitoes (Anopheles spp.) in captivity. The sustainable and reliable ...

Universidade Nova de Lisboa, IHMT-NOVA

Highly polymorphic regions of the circumsporozoite protein (CSP) of Plasmodium falciparum are associated with cellular immune responses. One of these regions, the TH3R polymorfic region of the csp gene codes for known T-cell epitopes. The present study tested the use of SSCP to determine sequence variations of the TH3R regions of four clones of P. falciparum (3D7, HB3, Dd2 and K1) which are known to have different TH3R regions. Single-strand conformation polymorphism (SSCP) technique was performed on amplified products labelled with fluorescent primer (both strands) and electrophoresed in an automated sequencer. Various gel compositions and electrophoresis conditions were tested. Even if some electrophoretogram differences were observed between clones, they could not distinguish between the alleles.

Single strand conformational polymorphism evaluation for the identification of TH3R alleles of the circumsporozoite protein gene of Plasmodium falciparum.

The anti-malarial chloroquine can modulate the outcome of infection during the Plasmodium sporogonic development, interfering with Plasmodium gene expression and subsequently, with transmission. The present study sets to identify Plasmodium genes that might be regulated by chloroquine in the mosquito vector.

Effect of chloroquine on gene expression of Plasmodium yoelii nigeriensis during its sporogonic development in the mosquito vector.

Unmethylated CpG dinucleotide motifs in bacterial DNA or in synthetic oligodeoxynucleotides (ODN) are potent stimulators of the vertebrate innate immune system. However, the potential of these DNA species to modulate mosquito immunity have not been explored. In the present study, we investigated the effects of CpG-ODN on the outcome of Plasmodium infection in insects and on the modulation of mosquito immunity to Plasmodium. Anopheles stephensi and Anopheles gambiae mosquitoes inoculated with CpG-ODN showed significant reductions in the prevalence of Plasmodium infection, intensity of Plasmodium infection, and number of eggs produced. Microarrays were used to elucidate the transcriptional profiles of the fat bodies of CpG-ODN-treated mosquitoes. In total, 172 genes were differentially expressed, of which 136 were up-regulated and 36 were down-regulated. The major functional class of CpG-ODN-regulated genes encoded immune response-related proteins (31%). Within this group, genes associated with coagulation/wound healing were the most frequently represented (23%). Knockdown of a transglutaminase gene that was up-regulated by the CpG-ODN and chemical inhibition of the enzyme resulted in a significant increase in Plasmodium infection. Mosquitoes that were treated with CpG-ODNs were found to be less susceptible to Plasmodium infection. Transcriptional profiling of the fat body suggests that protection is associated with coagulation/wound healing. We show for the first time that transglutaminase activity plays a role in the control of Plasmodium infection.

CpG-containing oligodeoxynucleotides increases resistance of Anopheles mosquitoes to Plasmodium infection.

Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU's. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil.

Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon.

Malaria is a worldwide infectious disease caused by Plasmodium parasites and transmitted by female Anopheles mosquitoes. The malaria vector mosquito Anopheles can trigger effective mechanisms to control completion of the Plasmodium lifecycle; the mosquito immune response to the parasite involves several pathways which are not yet well characterized. Plasmodium metabolite hemozoin has emerged as a potent immunostimulator of mammalian tissues. In this study, we aim to investigate the role of this parasite's by-product as stimulator of Anopheles gambiae immunity to Plasmodium berghei.

Hemozoin activates the innate immune system and reduces Plasmodium berghei infection in Anopheles gambiae.

Mosquito breeding depends on the supply of fresh vertebrate blood, a major bottleneck for large-scale production of Anopheles spp. Feeding alternatives to fresh blood are thus a priority for research, outdoor large-cage trials and control interventions. Several artificial meal compositions were tested and Anopheles oogenesis, egg laying and development into the next generation of adult mosquitoes were followed. We identified blood-substitute-diets that supported ovarian development, egg maturation and fertility as well as, low progeny larval mortality, and normal development of offspring into adult mosquitoes. The formulated diet is an effective artificial meal, free of fresh blood that mimics a vertebrate blood meal and represents an important advance for the sustainability of Anopheles mosquito rearing in captivity.

Article	Year
Single strand conformational polymorphism evaluation for the identification of TH3R alleles of the circumsporozoite protein gene of Plasmodium falciparum. Parassitologia\| PubMed ID: 12402522	2001
Effect of chloroquine on gene expression of Plasmodium yoelii nigeriensis during its sporogonic development in the mosquito vector. Malaria journal\| PubMed ID: 17605769	2007
CpG-containing oligodeoxynucleotides increases resistance of Anopheles mosquitoes to Plasmodium infection. Insect biochemistry and molecular biology\| PubMed ID: 22885118	2012
Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon. Parasites & vectors\| PubMed ID: 24916362	2014
Hemozoin activates the innate immune system and reduces Plasmodium berghei infection in Anopheles gambiae. Parasites & vectors\| PubMed ID: 25573379	2015
Fresh-blood-free diet for rearing malaria mosquito vectors. Scientific reports\| PubMed ID: 30546023	2018

Henrique Silveira

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