Infection with Plasmodium berghei ookinetes alters protein expression in the brain of Anopheles albimanus mosquitoes

Dietary and Plasmodium challenge effects on the cuticular hydrocarbon profile of Anopheles albimanus

The cuticular hydrocarbon (CHC) profile reflects the insects' physiological states. These include age, sex, reproductive stage, and gravidity. Environmental factors such as diet, relative humidity or exposure to insecticides also affect the CHC composition in mosquitoes. In this work, the CHC profile was analyzed in two Anopheles albimanus phenotypes with different degrees of susceptibility to Plasmodium, the susceptible-White and resistant-Brown phenotypes, in response to the two dietary regimes of mosquitoes: a carbon-rich diet (sugar) and a protein-rich diet (blood) alone or containing Plasmodium ookinetes. The CHCs were analyzed by gas chromatography coupled to mass spectrometry or flame ionization detection, identifying 19 CHCs with chain lengths ranging from 20 to 37 carbons. Qualitative and quantitative changes in CHCs composition were dependent on diet, a parasite challenge, and, to a lesser extent, the phenotype. Blood-feeding caused up to a 40% reduction in the total CHC content compared to sugar-feeding. If blood contained ookinetes, further changes in the CHC profile were observed depending on the Plasmodium susceptibility of the phenotypes. Higher infection prevalence caused greater changes in the CHC profile. These dietary and infection-associated modifications in the CHCs could have multiple effects on mosquito fitness, impacts on disease transmission, and tolerance to insecticides.

Prediction of malaria transmission drivers in Anopheles mosquitoes using artificial intelligence coupled to MALDI-TOF mass spectrometry

Vector control programmes are a strategic priority in the fight against malaria. However, vector control interventions require rigorous monitoring. Entomological tools for characterizing malaria transmission drivers are limited and are difficult to establish in the field. To predict Anopheles drivers of malaria transmission, such as mosquito age, blood feeding and Plasmodium infection, we evaluated artificial neural networks (ANNs) coupled to matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) and analysed the impact on the proteome of laboratory-reared Anopheles stephensi mosquitoes. ANNs were sensitive to Anopheles proteome changes and specifically recognized spectral patterns associated with mosquito age (0–10 days, 11–20 days and 21–28 days), blood feeding and P. berghei infection, with best prediction accuracies of 73%, 89% and 78%, respectively. This study illustrates that MALDI-TOF MS coupled to ANNs can be used to predict entomological drivers of malaria transmission, providing potential new tools for vector control. Future studies must assess the field validity of this new approach in wild-caught adult Anopheles. A similar approach could be envisaged for the identification of blood meal source and the detection of insecticide resistance in Anopheles and to other arthropods and pathogens.

Trypanosoma cruzi Calreticulin: Immune Evasion, Infectivity, and Tumorigenesis

To successfully infect, Trypanosoma cruzi evades and modulates the host immune response. T. cruzi calreticulin (TcCalr) is a multifunctional, endoplasmic reticulum (ER)-resident chaperone that, translocated to the external microenvironment, mediates crucial host-parasite interactions. TcCalr binds and inactivates C1 and mannose-binding lectin (MBL)/ficolins, important pattern- recognition receptors (PRRs) of the complement system. Using an apoptotic mimicry strategy, the C1-TcCalr association facilitates the infection of target cells. T. cruzi infection also seems to confer protection against tumorigenesis. Thus, recombinant TcCalr has important antiangiogenic properties, detected in vitro, ex vivo, and in ovum, most likely contributing at least in part, to its antitumor properties. Consequently, TcCalr is useful for investigating key issues of host-parasite interactions and possible new immunological/pharmacological interventions in the areas of Chagas' disease and experimental cancer.

Hemolymph protein profiles of subterranean termite Reticulitermes flavipes challenged with methicillin resistant Staphylococcus aureus or Pseudomonas aeruginosa

When the subterranean termite Reticulitermes flavipes is fed heat-killed methicillin resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa, the termite produces proteins with antibacterial activity against the inducer pathogen in its hemolymph. We used a proteomic approach to characterize the alterations in protein profiles caused by the inducer bacterium in the hemolymph of the termite. Nano-liquid chromatography-tandem mass spectrometry analysis identified a total of 221 proteins and approximately 70% of these proteins could be associated with biological processes and molecular functions. Challenges with these human pathogens induced a total of 57 proteins (35 in MRSA-challenged, 16 in P. aeruginosa-challenged, and 6 shared by both treatments) and suppressed 13 proteins by both pathogens. Quasi-Poisson likelihood modeling with false discovery rate adjustment identified a total of 18 and 40 proteins that were differentially expressed at least 2.5-fold in response to MRSA and P. aeruginosa-challenge, respectively. We selected 7 differentially expressed proteins and verified their gene expression levels via quantitative real-time RT-PCR. Our findings provide an initial insight into a putative termite immune response against MRSA and P. aeruginosa-challenge.