scholarly journals High-Throughput Identification of the Rhodnius prolixus Midgut Proteome Unravels a Sophisticated Hematophagic Machinery

Proteomes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 16 ◽  
Author(s):  
Radouane Ouali ◽  
Karen Caroline Valentim de Brito ◽  
Didier Salmon ◽  
Sabrina Bousbata
Keyword(s):  
Digestive Tract ◽  
Chagas Disease ◽  
High Throughput ◽  
Control Strategies ◽  
Anterior Part ◽  
Rhodnius Prolixus ◽  
Etiologic Agent ◽  
Parasitic Infections ◽  
Developmental Cycle ◽  
Starting Point

Chagas disease is one of the most common parasitic infections in Latin America, which is transmitted by hematophagous triatomine bugs, of which Rhodnius prolixus is the vector prototype for the study of this disease. The protozoan parasite Trypanosoma cruzi, the etiologic agent of this disease, is transmitted by the vector to humans through the bite wound or mucosa. The passage of the parasite through the digestive tract of its vector constitutes a key step in its developmental cycle. Herewith, by a using high-throughput proteomic tool in order to characterize the midgut proteome of R. prolixus, we describe a set of functional groups of proteins, as well as the biological processes in which they are involved. This is the first proteomic analysis showing an elaborated hematophagy machinery involved in the digestion of blood, among which, several families of proteases have been characterized. The evaluation of the activity of cathepsin D proteases in the anterior part of the digestive tract of the insect suggested the existence of a proteolytic activity within this compartment, suggesting that digestion occurs early in this compartment. Moreover, several heat shock proteins, blood clotting inhibitors, and a powerful antioxidant enzyme machinery against reactive oxygen species (ROS) and cell detoxification have been identified. Highlighting the complexity and importance of the digestive physiology of insects could be a starting point for the selection of new targets for innovative control strategies of Chagas disease.

scholarly journals Comparative dissection of the peripheral olfactory system of the Chagas disease vectors Rhodnius prolixus and Rhodnius brethesi

2021 ◽  
Vol 15 (4) ◽  
pp. e0009098
Author(s):  
Florencia Campetella ◽  
Rickard Ignell ◽  
Rolf Beutel ◽  
Bill S. Hansson ◽  
Silke Sachse
Keyword(s):  
Chagas Disease ◽  
Olfactory System ◽  
Control Strategies ◽  
Natural Habitat ◽  
Rhodnius Prolixus ◽  
Functional Study ◽  
Olfactory Responses ◽  
Efficient Vector ◽  
Vertebrate Hosts ◽  
Morphological Differences

American trypanosomiasis, or Chagas disease, is transmitted by both domestic and sylvatic species of Triatominae which use sensory cues to locate their vertebrate hosts. Among them, odorants have been shown to play a key role. Previous work revealed morphological differences in the sensory apparatus of different species of Triatomines, but to date a comparative functional study of the olfactory system is lacking. After examining the antennal sensilla with scanning electronic microscopy (SEM), we compared olfactory responses of Rhodnius prolixus and the sylvatic Rhodnius brethesi using an electrophysiological approach. In electroantennogram (EAG) recordings, we first showed that the antenna of R. prolixus is highly responsive to carboxylic acids, compounds found in their habitat and the headspace of their vertebrate hosts. We then compared responses from olfactory sensory neurons (OSNs) housed in the grooved peg sensilla of both species, as these are tuned to these compounds using single-sensillum recordings (SSRs). In R. prolixus, the SSR responses revealed a narrower tuning breath than its sylvatic sibling, with the latter showing responses to a broader range of chemical classes. Additionally, we observed significant differences between these two species in their response to particular volatiles, such as amyl acetate and butyryl chloride. In summary, the closely related, but ecologically differentiated R. prolixus and R. brethesi display distinct differences in their olfactory functions. Considering the ongoing rapid destruction of the natural habitat of sylvatic species and the likely shift towards environments shaped by humans, we expect that our results will contribute to the design of efficient vector control strategies in the future.

scholarly journals Comparative dissection of the peripheral olfactory system of the Chagas disease vectors Rhodnius prolixus and Rhodnius brethesi

2021 ◽  
Author(s):  
Florencia Campetella ◽  
Rickard Ignell ◽  
Rolf Beutel ◽  
Bill S. Hansson ◽  
Silke Sachse
Keyword(s):  
Chagas Disease ◽  
Olfactory System ◽  
Control Strategies ◽  
Natural Habitat ◽  
Rhodnius Prolixus ◽  
Functional Study ◽  
Domestic Species ◽  
Olfactory Responses ◽  
Efficient Vector ◽  
Morphological Differences

American trypanosomiasis or Chagas disease is thought to be transmitted by both domestic and sylvatic species of Triatominae. These haematophagous insects use sensory cues to find their vertebrate hosts. Among them, odorants have been shown to play a key role. Previous work revealed morphological differences in the sensory apparatus of sylvatic and domestic species of Triatomines, but to date a functional study of the olfactory system is not available. After examining the antennal sensilla with scanning electronic microscopy (SEM), we compared olfactory responses of the domestic Rhodnius prolixus and the sylvatic Rhodnius brethesi with an electrophysiological approach. In electroantennogram (EAG) recordings, we first show that the antenna of R. prolixus shows high responses to carboxylic acids, compounds found in their habitat and headspace of hosts. We then compared responses from olfactory sensory neurons (OSNs) housed in the grooved peg sensilla of both species as these are tuned to these compounds using single-sensillum recordings (SSR). In R. prolixus , the SSR responses revealed a narrower tuning breath than its sylvatic counterpart, with the latter showing responses to a broader range of chemical classes. Additionally, we observed significant differences between these two species in their response to particular volatiles, such as amyl acetate and butyryl chloride. In summary, the closely related, but ecologically differentiated R. prolixus and R. brethesi display distinct differences in their olfactory functions. Considering the ongoing rapid destruction of the natural habitat of sylvatic species and likely shifts towards environments shaped by humans, we expect that our results will contribute to the design of efficient vector control strategies in the future.

Unraveling the Importance of Triatomine (Hemiptera: Reduviidae: Triatominae) Feeding Sources in the Chagas Disease Context

2020 ◽  
Author(s):  
Alberto Antonio-Campos ◽  
Ricardo Alejandre-Aguilar ◽  
Nancy Rivas
Keyword(s):  
Chagas Disease ◽  
Control Strategies ◽  
Etiologic Agent ◽  
Effective Control ◽  
Vector Species ◽  
Research Papers ◽  
Scientific Publications ◽  
Current Review ◽  
Triatomine Species ◽  
Feeding Sources

Abstract The triatomines are vectors of Trypanosoma cruzi (Chagas, 1909), the etiologic agent of Chagas disease. All species are strictly hematophagous, and the hosts used by vector species are important to understand the transmission dynamics of T. cruzi, and eventually, for the development of effective control strategies in endemic countries. In the current review, we gather a comprehensively number of literature reporting triatomine feeding sources, using rigorous targeted search of scientific publications, which includes research papers and reviews to put together the most recent findings of the feeding behavior in triatomines and their applications for vector control of Chagas disease. Our main findings suggest that the main feeding source in triatomines is the human blood (22.75%), T. dimidiata (Latreille, 1811) (Hemiptera: Reduviidae) is the most frequent (13.68%) triatomine species in this type of study, and most of the studies on feeding sources (47.5%) are conducted in the domestic and peri-domestic environment.

scholarly journals Novel repellents for the blood-sucking insects Rhodnius prolixus and Triatoma infestans, vectors of Chagas disease

2019 ◽  
Author(s):  
Melanie Ramírez ◽  
Mario I. Ortiz ◽  
Pablo Guerenstein ◽  
Jorge Molina
Keyword(s):  
Chagas Disease ◽  
Dimethyl Sulfide ◽  
Control Strategies ◽  
Statistical Tests ◽  
Positive Control ◽  
Negative Control ◽  
Rhodnius Prolixus ◽  
Triatoma Infestans ◽  
Host Seeking ◽  
Blood Sucking

AbstractBackgroundStudying the behavioral response of blood-sucking, disease-vector insects to potentially repellent volatile compounds could shed light on the development of new control strategies. Volatiles released by human facial skin microbiota play different roles in the host-seeking behavior of triatomines. We assessed the repellency effect of such compounds of bacterial origin on Triatoma infestans and Rhodnius prolixus, two important vectors of Chagas disease in Latin America.MethodsUsing an exposure device, insects were presented to human odor alone (negative control) and in the presence of three individual tested compounds (2-mercaptoethanol, dimethyl sulfide and 2-phenylethanol, which was only tested in R. prolixus) and the gold-standard repellent NN-diethyl-3-methylbenzamide–DEET (positive control). We quantified the time the insects spent in the proximity of the host and performed nonparametric statistical tests to determine if any of the compounds evaluated affected the behavior of the insect.ResultsWe found volatiles that significantly reduced the time spent in the proximity of the host. These were 2-phenylethanol and 2-mercaptoethanol for R. prolixus, and dimethyl sulfide and 2-mercaptoethanol for T. infestans. Such an effect was also observed in both species when DEET was presented, although only at the higher doses tested.ConclusionsThe new repellents modulated the behavior of two Chagas disease vectors belonging to two different triatomine tribes, and this was achieved using a dose up to three orders of magnitude lower than that needed to evoke the same effect with DEET. Future efforts in understanding deeply the mechanism of action of repellent compounds such as 2-mercaptoethanol, as well as an assessment of their temporal and spatial repellent properties, could lead to the development of novel control strategies for insect vectors refractory to DEET.

Major Kinds of Drug Targets in Chagas Disease or American Trypanosomiasis

2019 ◽  
Vol 20 (11) ◽  
pp. 1203-1216 ◽  
Author(s):  
Vilma G. Duschak
Keyword(s):  
Chagas Disease ◽  
Latin American ◽  
Drug Targets ◽  
Defense Mechanisms ◽  
Cysteine Proteinase ◽  
Parasitic Infection ◽  
Etiologic Agent ◽  
World Health ◽  
American Trypanosomiasis ◽  
Group I

American Trypanosomiasis, a parasitic infection commonly named Chagas disease, affects millions of people all over Latin American countries. Presently, the World Health Organization (WHO) predicts that the number of international infected individuals extends to 7 to 8 million, assuming that more than 10,000 deaths occur annually. The transmission of the etiologic agent, Trypanosoma cruzi, through people migrating to non-endemic world nations makes it an emergent disease. The best promising targets for trypanocidal drugs may be classified into three main groups: Group I includes the main molecular targets that are considered among specific enzymes involved in the essential processes for parasite survival, principally Cruzipain, the major antigenic parasite cysteine proteinase. Group II involves biological pathways and their key specific enzymes, such as Sterol biosynthesis pathway, among others, specific antioxidant defense mechanisms, and bioenergetics ones. Group III includes the atypical organelles /structures present in the parasite relevant clinical forms, which are absent or considerably different from those present in mammals and biological processes related to them. These can be considered potential targets to develop drugs with extra effectiveness and fewer secondary effects than the currently used therapeutics. An improved distinction between the host and the parasite targets will help fight against this neglected disease.

scholarly journals Development of a High-Throughput Screening Assay to Identify Inhibitors of the SARS-CoV-2 Guanine-N7-Methyltransferase Using RapidFire Mass Spectrometry

2021 ◽  
pp. 247255522110006
Author(s):  
Lesley-Anne Pearson ◽  
Charlotte J. Green ◽  
De Lin ◽  
Alain-Pierre Petit ◽  
David W. Gray ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Mutational Analysis ◽  
Nonstructural Protein ◽  
Translation Efficiency ◽  
Screening Assay ◽  
High Throughput Screening Assay ◽  
Starting Point ◽  
Approved Drugs ◽  
High Throughput Assay

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) represents a significant threat to human health. Despite its similarity to related coronaviruses, there are currently no specific treatments for COVID-19 infection, and therefore there is an urgent need to develop therapies for this and future coronavirus outbreaks. Formation of the cap at the 5′ end of viral RNA has been shown to help coronaviruses evade host defenses. Nonstructural protein 14 (nsp14) is responsible for N7-methylation of the cap guanosine in coronaviruses. This enzyme is highly conserved among coronaviruses and is a bifunctional protein with both N7-methyltransferase and 3′-5′ exonuclease activities that distinguish nsp14 from its human equivalent. Mutational analysis of SARS-CoV nsp14 highlighted its role in viral replication and translation efficiency of the viral genome. In this paper, we describe the characterization and development of a high-throughput assay for nsp14 utilizing RapidFire technology. The assay has been used to screen a library of 1771 Food and Drug Administration (FDA)-approved drugs. From this, we have validated nitazoxanide as a selective inhibitor of the methyltransferase activity of nsp14. Although modestly active, this compound could serve as a starting point for further optimization.

scholarly journals Silencing the odorant receptor co-receptor RproOrco affects the physiology and behavior of the Chagas disease vector Rhodnius prolixus

2016 ◽  
Vol 69 ◽  
pp. 82-90 ◽  
Author(s):  
Thiago A. Franco ◽  
Daniele S. Oliveira ◽  
Monica F. Moreira ◽  
Walter S. Leal ◽  
Ana C.A. Melo
Keyword(s):  
Chagas Disease ◽  
Odorant Receptor ◽  
Rhodnius Prolixus ◽  
Disease Vector ◽  
And Behavior

Identification of Positive Allosteric Modulators of Glycine Receptors from a High-Throughput Screen Using a Fluorescent Membrane Potential Assay

2016 ◽  
Vol 21 (10) ◽  
pp. 1042-1053 ◽  
Author(s):  
Clara Stead ◽  
Adam Brown ◽  
Cathryn Adams ◽  
Sarah J. Nickolls ◽  
Gareth Young ◽  
...  
Keyword(s):  
Membrane Potential ◽  
High Throughput ◽  
Glycine Receptor ◽  
Functional Characterization ◽  
In Vitro Assays ◽  
Allosteric Modulators ◽  
Inhibitory Neurotransmission ◽  
Starting Point ◽  
Positive Allosteric Modulators

Glycine receptor 3 (GlyRα3) is a ligand-gated ion channel of the cys-loop family that plays a key role in mediating inhibitory neurotransmission and regulation of pain signaling in the dorsal horn. Potentiation of GlyRα3 function is therefore of interest as a putative analgesic mechanism with which to target new therapeutics. However, to date, positive allosteric modulators (PAMs) of this receptor with sufficient selectivity to enable target validation studies have not been described. To address this lack of pharmacological tools, we developed a suite of in vitro assays comprising a high-throughput fluorescent membrane potential screen and a medium-throughput electrophysiology assay using IonFlux HT together with conventional manual patch clamp. Using these assays, we conducted a primary screening campaign and report the structures of hit compounds identified as GlyR PAMs. Our functional characterization data reveal a hit compound with high efficacy relative to current known potentiators and selectivity over GABAAR, another major class of inhibitory neurotransmission receptors of importance to pain. These small-molecule GlyR PAMs have high potential both as early tool compounds to enable pharmacological studies of GlyR inhibitory neurotransmission and as a starting point for the development of potent, selective GlyRα3 PAMs as novel analgesics.

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