Identification of a fibrinogen-related protein (FBN9) gene in neotropical anopheline mosquitoes

<p>Abstract</p> <p>Background</p> <p>Malaria has a devastating impact on worldwide public health in many tropical areas. Studies on vector immunity are important for the overall understanding of the parasite-vector interaction and for the design of novel strategies to control malaria. A member of the fibrinogen-related protein family, <it>fbn9</it>, has been well studied in <it>Anopheles gambiae </it>and has been shown to be an important component of the mosquito immune system. However, little is known about this gene in neotropical anopheline species.</p> <p>Methods</p> <p>This article describes the identification and characterization of the <it>fbn9 </it>gene partial sequences from four species of neotropical anopheline primary and secondary vectors: <it>Anopheles darlingi, Anopheles nuneztovari, Anopheles aquasalis</it>, and <it>Anopheles albitarsis </it>(namely <it>Anopheles marajoara</it>). Degenerate primers were designed based on comparative analysis of publicly available <it>Aedes aegypti </it>and <it>An. gambiae </it>gene sequences and used to clone putative homologs in the neotropical species. Sequence comparisons and Bayesian phylogenetic analyses were then performed to better understand the molecular diversity of this gene in evolutionary distant anopheline species, belonging to different subgenera.</p> <p>Results</p> <p>Comparisons of the <it>fbn9 </it>gene sequences of the neotropical anophelines and their homologs in the <it>An. gambiae </it>complex (Gambiae complex) showed high conservation at the nucleotide and amino acid levels, although some sites show significant differentiation (non-synonymous substitutions). Furthermore, phylogenetic analysis of <it>fbn9 </it>nucleotide sequences showed that neotropical anophelines and African mosquitoes form two well-supported clades, mirroring their separation into two different subgenera.</p> <p>Conclusions</p> <p>The present work adds new insights into the conserved role of <it>fbn9 </it>in insect immunity in a broader range of anopheline species and reinforces the possibility of manipulating mosquito immunity to design novel pathogen control strategies.</p

Genetic diversity of chloroquine-resistant Plasmodium vivax parasites from the western Brazilian Amazon

The molecular basis of Plasmodium vivax chloroquine (CQ) resistance is still unknown. Elucidating the molecular background of parasites that are sensitive or resistant to CQ will help to identify and monitor the spread of resistance. By genotyping a panel of molecular markers, we demonstrate a similar genetic variability between in vitro CQ-resistant and sensitive phenotypes of P. vivax parasites. However, our studies identified two loci (MS8 and MSP1-B10) that could be used to discriminate between both CQ-susceptible phenotypes among P. vivax isolates in vitro. These preliminary data suggest that microsatellites may be used to identify and to monitor the spread of P. vivax-resistance around the world