The adult females of Aedes aegypti mosquitoes are facultative hematophagous insects but they are unable to feed on blood right after pupae emergence. The maturation process that takes place during ...the first post-emergence days, hereafter named hematophagic and gonotrophic capacitation, comprises a set of molecular and physiological changes that prepare the females for the first gonotrophic cycle. Notwithstanding, the molecular bases underlying mosquito hematophagic and gonotrophic capacitation remain obscure. Here, we investigated the molecular and biochemical changes in adult Ae. aegypti along the first four days post-emergence, prior to a blood meal. We performed a RNA-Seq analysis of the head and body, comparing male and female gene expression time courses. A total of 811 and 203 genes were differentially expressed, respectively in the body and head, and both body parts showed early, mid, and late female-specific expression profiles. Female-specific up-regulation of genes involved in muscle development and the oxidative phosphorylation pathway were remarkable features observed in the head. Functional assessment of mitochondrial oxygen consumption in heads showed a gradual increase in respiratory capacity and ATP-linked respiration as a consequence of induced mitochondrial biogenesis and content over time. This pattern strongly suggests that boosting oxidative phosphorylation in heads is a required step towards blood sucking habit. Several salivary gland genes, proteases, and genes involved in DNA replication and repair, ribosome biogenesis, and juvenile hormone signaling were up-regulated specifically in the female body, which may reflect the gonotrophic capacitation. This comprehensive description of molecular and biochemical mechanisms of the hematophagic and gonotrophic capacitation in mosquitoes unravels potentially new targets for vector control.
Leishmaniasis consists of a group of neglected diseases, which affect millions of people worldwide. First- and second-line chemotherapies, which present high toxicity and variable efficacy, have been ...available for decades leading to the appearance of resistance. Globally, volatile oils have received much attention due to their increase use as effective bioactive compounds in folk medicine. They have been employed against
Leishmania
parasites with a positive impact in the treatment of this neglected disease. In this review, the leishmanicidal activity of volatile oils and their isolates have been described as promising novel candidate molecules for the development of leishmanicidal drugs. The purpose of this review is to critically discuss several works published between 2000 and 2020 that have described the utilization of volatile oils and some of their active principles from diverse plant sources against different species of
Leishmania
.
Graphical Abstract
Trypanosoma cruzi
is the etiological agent of Chagas disease. These parasites undergo dramatic morphological and physiological changes during their life cycle. The human-infective metacyclic ...trypomastigotes differentiate from epimastigotes inside the midgut of the Triatominae insect vector. Our group has shown that the saliva and feces of
Rhodnius prolixus
contains a lysophospholipid, lysophosphatidylcholine (LPC), which modulates several aspects of
T. cruzi
infection in macrophages. LPC hydrolysis by a specific lysophospholipase D, autotaxin (ATX), generates lysophosphatidic acid (LPA). These bioactive lysophospholipids are multisignaling molecules and are found in human plasma ingested by the insect during blood feeding. Here, we show the role of LPC and LPA in
T. cruzi
proliferation and differentiation. Both lysophospholipids are able to induce parasite proliferation. We observed an increase in parasite growth with different fatty acyl chains, such as C18:0, C16:0, or C18:1 LPC. The dynamics of LPC and LPA effect on parasite proliferation was evaluated in vivo through a time- and space-dependent strategy in the vector gut. LPC but not LPA was also able to affect parasite metacyclogenesis. Finally, we determined LPA and LPC distribution in the parasite itself. Such bioactive lipids are associated with reservosomes of
T. cruzi
. To the best of our knowledge, this is the first study to suggest the role of surrounding bioactive lipids ingested during blood feeding in the control of parasite transmission.
Trypanosoma cruzi is the causative agent of Chagas disease which affects 8 million people in Latin America. The parasite possesses high capacity to evade host immune system and the available drugs to ...treat Chagas disease present low efficacy combined to serious side effects to patients. Therefore, the identification of alternative therapeutics is essential. Brazilian flora exhibits an immense diversity of metabolites with great potential to be developed into new drugs. We investigated the action of 2″,3″-dihydroochnaflavone a biflavonoid extracted from Luxemburgia nobilis Eichler ex Engl. (Ochnaceae) against T. cruzi (Y strain). Our experiments showed that this compound is effective against parasite epimastigote forms, presenting IC50 value of (2.5 ± 0.1) μM after 96 h of treatment. Ultrastructure alterations were also detected in treated epimastigotes especially mitochondrial enlargement at the kinetoplast region. At the concentration of 30 μM, the compound killed (61.6 ± 3.37)% of the parasite in its amastigote form. In addition, at the same concentration, the compound killed all trypamastigotes growing within murine macrophages after 7–9 days of infection. Nonetheless, the biflavonoid concentrations were harmless to murine enriched population of lymphocytes and peritoneal macrophages. These results indicate that 2″,3″- dihydroochnaflavone presents activity against T. cruzi.
Functional insect vector colonies are essential for the study of their biology, evolution, behavior as well as control strategies of these organisms that transmit pathogens of medical and veterinary ...importance. In addition to the establishment, improvement and adaptation of pre-established protocols in the maintenance of a colony is important, as it may result in higher production of insects. Stomoxys calcitrans or stable fly causes important economic losses in production of beef and milk, besides mechanically transmitting a great variety of pathogens to cattle. In order to generate flies under laboratory conditions, a colony of S. calcitrans was established at our laboratory considering local environment geographical characteristics. Adults collected in UFRRJ campus were kept in the laboratory and maintained with daily feeding on anticoagulant-containing bovine blood offered in disposable sanitary napkins. Immature forms were maintained on diets rich in organic matter. The colony temperature and relative humidity were daily monitored as well as the development of insects. The monthly measured biological parameters included the development of eggs into pupae, of pupae into F1 adults and the comparison of the number of flies collected in the field with the number of F1 flies emerged in the laboratory. The data presented here was obtained from March to November 2019. In that period, the average per month of flies collected in the field was 604.2, of generated eggs was 2694.3, of generated pupae was 349.5 and of generated F1 flies in the laboratory was 205.9. Fluctuations of abiotic and biological factors contributed to an uneven production of flies in the colony throughout the months. This is the first report with numerical quantification of S. calcitrans flies production in a laboratory in Brazil. Some methodologies used in the colony shall be reevaluated and modified with the goal of obtaining higher numbers of flies generated in the laboratory over time.
•A colony of Stomoxys calcitrans was established in Seropédica, RJ, Brazil.•Colony production parameters - eggs, pupae and F1 adults - were monthly quantified.•In general, the conversion of egg to adult F1 was not high.•Higher production of F1 adults occurred in months with mild temperatures.
All life cycle stages of the protozoan parasite Trypanosoma cruzi are enveloped by mucin-like glycoproteins which, despite major changes in their polypeptide cores, are extensively and similarly ...O-glycosylated. O-Glycan biosynthesis is initiated by the addition of αGlcNAc to Thr in a reaction catalyzed by Golgi UDP-GlcNAc:polypeptide O-α-N-acetyl-d-glucosaminyltransferases (ppαGlcNAcTs), which are encoded by TcOGNT1 and TcOGNT2. We now directly show that TcOGNT2 is associated with the Golgi apparatus of the epimastigote stage and is markedly downregulated in both differentiated metacyclic trypomastigotes (MCTs) and cell culture-derived trypomastigotes (TCTs). The significance of downregulation was examined by forced continued expression of TcOGNT2, which resulted in a substantial increase of TcOGNT2 protein levels but only modestly increased ppαGlcNAcT activity in extracts and altered cell surface glycosylation in TCTs. Constitutive TcOGNT2 overexpression had no discernible effect on proliferating epimastigotes but negatively affected production of both types of trypomastigotes. MCTs differentiated from epimastigotes at a low frequency, though they were apparently normal based on morphological and biochemical criteria. However, these MCTs exhibited an impaired ability to produce amastigotes and TCTs in cell culture monolayers, most likely due to a reduced infection frequency. Remarkably, inhibition of MCT production did not depend on TcOGNT2 catalytic activity, whereas TCT production was inhibited only by active TcOGNT2. These findings indicate that TcOGNT2 downregulation is important for proper differentiation of MCTs and functioning of TCTs and that TcOGNT2 regulates these functions by using both catalytic and noncatalytic mechanisms.
Transmission blocking vaccines are one of the control strategies for vector-transmitted protozoan diseases. Antibodies raised in the vaccinated host prevent the development of the parasite in the ...insect vector, interrupting the epidemiological cycle. The FML antigen of
Leishmania donovani in combination with saponin (FML-vaccine and Leishmune
®) induced 92–97% of protections against zoonotic visceral leishmaniasis. We assayed the ability of FML to inhibit
Leishmania donovani and
Leishmania chagasi procyclic promastigote-binding to dissected
Lutzomyia longipalpis midguts. We found a dose-dependent inhibition, more pronounced on
L. donovani (80%) than on
L. chagasi promastigotes (
p
<
0.001). On the other hand, the Fab-IgG serum fraction of Leishmune
® vaccinated dogs (IgG2 predominant), also inhibited parasite binding in a dose-response (
p
<
0.0001) with an equally potent effect against
L. donovani or
L. chagasi (
p
=
0.061). The transmission blocking properties of the Leishmune
® vaccine was also assessed by an in vivo membrane assay, with sand flies fed with 1.5
×
10
7 amastigotes, human blood and, vaccinated or normal control dog sera. Significantly higher values were found in rate of infection (
p
<
0.025) and intensity of infection (number of parasites/insect) (
p
<
0.05) of control sand flies, making a very reduced infection index (20.7%) in the vaccine group. Our results disclosed that the Leishmune
® vaccine is a TBV, and that the dog antibodies present in sera, even 12 months after vaccination, lead to a significant effective protection of 79.3%.
Blood-sucking insects are responsible for the transmission of several important disease-causing organisms such as viruses, bacteria, and protozoans. The hematophagous hemipteran Rhodnius prolixus is ...one of the most important vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Due to the medical importance of this insect, it has been used as a study model in physiology and biochemistry since the 1930s. Artificial feeding has been recognized as a feasible and a more ethical alternative method of feeding these hematophagous insects. To prevent clotting after blood collection defibrination or treatment with anticoagulants are necessary. Although anticoagulants have been routinely used for stabilizing the collected blood, there is a gap in demonstration of the effects of using anticoagulants on the feeding and development of the hematophagous insect Rhodnius prolixus. In this study, we compared the survival rate, molting efficiency, fertility, and infection development between insects that were fed on blood containing three different anticoagulants (citrate, EDTA, and heparin). We observed that fifth instar nymphs that were fed on blood containing EDTA and citrate could not perform digestion properly, which resulted in molting inefficiency. Adult insects that were fed on EDTA-containing blood laid lower number of eggs, and also had a diminished egg hatch percentage. When we delivered T. cruzi parasites in blood containing citrate or EDTA to the insects, a lower number of parasites and metacyclic trypomastigotes was observed in the intestine compared to the group fed on heparin-containing blood. Since heparin could potentially inhibit DNA polymerase activity in DNA samples extracted from the intestine, we analyzed different heparin concentrations to determine which one is the best for use as an anticoagulant. Concentrations ranging between 2.5 and 5 U/mL were able to inhibit coagulation without severely impairing DNA polymerase activity, thus indicating that this should be considered as the range of use for feeding experiments. Our results suggest that among the three anticoagulants tested, heparin can be recommended as the anticoagulant of choice for R. prolixus feeding experiments.
Trypanosoma cruzi presents considerable genetic and protein profile polymorphism among different parasite populations. In a previous work, our group indicated cysteine and metalloprotease activities ...as good markers for separating T. cruzi I (TCI) from T. cruzi II (TCII) isolates, with higher heterogeneity among TCII isolates. Here, we have investigated the expression level of surface cruzipain in 16 field isolates belonging to the genotype TCI (n = 8) and TCII (n = 8) of T. cruzi. By means of flow cytometry analyses, using an anti-cruzipain polyclonal antibody, we observed a highly heterogeneous pattern of surface cruzipain molecules in these isolates, independently of their genotypes, cell measurements (size and granularity), original hosts, or biomes. However, fluorescence labeling tended to be stronger in TCI than in TCII population. Interestingly, isolates that expressed higher levels of surface cruzipain also yielded elevated levels of metacyclogenesis in vitro.
PDF
