The blood-sucking hemipteran Rhodnius prolixus is one of the main vectors of Chagas disease, a neglected tropical disease that affects several million people worldwide. Consuming a blood meal and mating are events with a high epidemiological impact since after each meal, mated females can lay fertile eggs that result in hundreds of offspring. Thus, a better knowledge of the control of R. prolixus reproductive capacity may provide targets for developing novel strategies to control vector populations, thereby reducing vector-host contacts and disease transmission. Here, we have used a combination of gene transcript expression analysis, biochemical assays, hormone measurements and studies of locomotory activity to investigate how mating influences egg development and egg laying rates in R. prolixus females. The results demonstrate that a blood meal increases egg production capacity and leads to earlier egg laying in mated females compared to virgins. Virgin females, however, have increased survival rate over mated females. Circulating juvenile hormone (JH) and ecdysteroid titers are increased in mated females, a process mainly driven through an upregulation of the transcripts for their biosynthetic enzymes in the corpus allatum and ovaries, respectively. Mated females display weaker locomotory activity compared to virgin females, mainly during the photophase. In essence, this study shows how reproductive output and behaviour are profoundly influenced by mating, highlighting molecular, biochemical, endocrine and behavioral features differentially expressed in mated and virgin R. prolixus females.
- MeSH
- Chagasova nemoc * MeSH
- kladení vajíček fyziologie MeSH
- lidé MeSH
- paraziti * MeSH
- Rhodnius * fyziologie MeSH
- rozmnožování MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Triatomines are vectors of Chagas disease and important model organisms in insect physiology. "Kissing bugs" are obligatory hematophagous insects. A blood meal is required to successfully complete oogenesis, a process primarily controlled by juvenile hormone (JH). We used Dipetalogaster maxima as an experimental model to further understand the roles of JH in the regulation of vitellogenesis and oogenesis. A particular focus was set on the role of JH controlling lipid and protein recruitment by the oocytes. The hemolymph titer of JH III skipped bisepoxide increased after a blood meal. Following a blood meal there were increased levels of mRNAs in the fat body for the yolk protein precursors, vitellogenin (Vg) and lipophorin (Lp), as well as of their protein products in the hemolymph; mRNAs of the Vg and Lp receptors (VgR and LpR) were concomitantly up-regulated in the ovaries. Topical administration of JH induced the expression of Lp/LpR and Vg/VgR genes, and prompted the uptake of Lp and Vg in pre-vitellogenic females. Knockdown of the expression of LpR by RNA interference in fed females did not impair the Lp-mediated lipid transfer to oocytes, suggesting that the bulk of lipid acquisition by oocytes occurred by other pathways rather than by the endocytic Lp/LpR pathway. In conclusion, our results strongly suggest that JH signaling is critical for lipid storage in oocytes, by regulating Vg and Lp gene expression in the fat body as well as by modulating the expression of LpR and VgR genes in ovaries.
- MeSH
- hmyz metabolismus fyziologie MeSH
- hmyzí proteiny metabolismus MeSH
- juvenilní hormony metabolismus MeSH
- lipoproteiny metabolismus MeSH
- metabolismus lipidů * MeSH
- oocyty metabolismus MeSH
- oogeneze fyziologie MeSH
- ovarium metabolismus MeSH
- receptory cytoplazmatické a nukleární metabolismus MeSH
- RNA interference MeSH
- signální transdukce MeSH
- Triatominae * metabolismus fyziologie MeSH
- vitelogeneze fyziologie MeSH
- vitelogeniny metabolismus MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
BACKGROUND: Kissing bugs (Triatominae) are blood-feeding insects best known as the vectors of Trypanosoma cruzi, the causative agent of Chagas' disease. Considering the high epidemiological relevance of these vectors, their biology and bacterial symbiosis remains surprisingly understudied. While previous investigations revealed generally low individual complexity but high among-individual variability of the triatomine microbiomes, any consistent microbiome determinants have not yet been identified across multiple Triatominae species. METHODS: To obtain a more comprehensive view of triatomine microbiomes, we investigated the host-microbiome relationship of five Triatoma species sampled from white-throated woodrat (Neotoma albigula) nests in multiple locations across the USA. We applied optimised 16S rRNA gene metabarcoding with a novel 18S rRNA gene blocking primer to a set of 170 T. cruzi-negative individuals across all six instars. RESULTS: Triatomine gut microbiome composition is strongly influenced by three principal factors: ontogeny, species identity, and the environment. The microbiomes are characterised by significant loss in bacterial diversity throughout ontogenetic development. First instars possess the highest bacterial diversity while adult microbiomes are routinely dominated by a single taxon. Primarily, the bacterial genus Dietzia dominates late-stage nymphs and adults of T. rubida, T. protracta, and T. lecticularia but is not present in the phylogenetically more distant T. gerstaeckeri and T. sanguisuga. Species-specific microbiome composition, particularly pronounced in early instars, is further modulated by locality-specific effects. In addition, pathogenic bacteria of the genus Bartonella, acquired from the vertebrate hosts, are an abundant component of Triatoma microbiomes. CONCLUSION: Our study is the first to demonstrate deterministic patterns in microbiome composition among all life stages and multiple Triatoma species. We hypothesise that triatomine microbiome assemblages are produced by species- and life stage-dependent uptake of environmental bacteria and multiple indirect transmission strategies that promote bacterial transfer between individuals. Altogether, our study highlights the complexity of Triatominae symbiosis with bacteria and warrant further investigation to understand microbiome function in these important vectors. Video abstract.
- MeSH
- Chagasova nemoc parazitologie MeSH
- divoká zvířata klasifikace mikrobiologie MeSH
- mikrobiota genetika fyziologie MeSH
- RNA ribozomální 16S genetika MeSH
- Triatominae klasifikace mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- audiovizuální média MeSH
- časopisecké články MeSH
- práce podpořená grantem MeSH
Juvenile hormones (JHs) are sesquiterpenoids synthesized by the corpora allata (CA). They play critical roles during insect development and reproduction. The first JH was described in 1934 as a "metamorphosis inhibitory hormone" in Rhodnius prolixus by Sir Vincent B. Wigglesworth. Remarkably, in spite of the importance of R. prolixus as vectors of Chagas disease and model organisms in insect physiology, the original JH that Wigglesworth described for the kissing-bug R. prolixus remained unidentified. We employed liquid chromatography mass spectrometry to search for the JH homologs present in the hemolymph of fourth instar nymphs of R. prolixus. Wigglesworth's original JH is the JH III skipped bisepoxide (JHSB3), a homolog identified in other heteropteran species. Changes in the titer of JHSB3 were studied during the 10-day long molting cycle of 4th instar nymph, between a blood meal and the ecdysis to 5th instar. In addition we measured the changes of mRNA levels in the CA for the 13 enzymes of the JH biosynthetic pathway during the molting cycle of 4th instar. Almost 90 years after the first descriptions of the role of JH in insects, this study finally reveals that the specific JH homolog responsible for Wigglesworth's original observations is JHSB3.
- MeSH
- biologická proměna * MeSH
- corpora allata chemie MeSH
- epoxidové sloučeniny chemie MeSH
- hemolymfa chemie MeSH
- kukla chemie fyziologie MeSH
- nymfa chemie fyziologie MeSH
- Rhodnius chemie fyziologie MeSH
- seskviterpeny chemie MeSH
- shazování tělního pokryvu fyziologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Dirofilaria immitis and D. repens are mosquito-borne nematodes, primarily infecting dogs, but also other species of carnivores and even humans. Given their impact on animal and human health, the transmission of these filarioids has been widely studied. The microfilariaemia has been shown to have a circadian variation for both Dirofilaria species infecting dogs. Due to methodological difficulties, the periodicity was only studied using venous blood samples, while the mosquitoes feed, in fact, on capillary blood. In this context, the present study aimed to test the feasibility of using triatomine bugs for the collection of capillary blood and to comparatively evaluate the level of microfilariaemia and its circadian variation in capillary blood vs. peripheral venous blood in a dog naturally co-infected with D. immitis and D. repens. The results showed a feeding success of 50%, with variations in the blood meal volume that the bugs ingested. The relative values of microfilariaemia (mf/bug) were strongly correlated with the volume of blood recovered: the more blood recovered from each bug, the higher values of microfilariaemia in the evening samples while the opposite results were obtained for the morning samples. The counting of microfilariae revealed a dominance of D. immitis in all the samples, but with significantly higher microfilariaemia in the venous blood. Meanwhile, for D. repens, the situation was opposite, with higher counts in the capillary blood samples. Our study showed that triatomine bugs can be used as a model for the collection and study of microfilariaemia in the capillary blood in mammals.
- MeSH
- cirkadiánní rytmus MeSH
- Dirofilaria immitis izolace a purifikace fyziologie MeSH
- Dirofilaria repens izolace a purifikace fyziologie MeSH
- dirofilarióza diagnóza parazitologie MeSH
- kapiláry parazitologie MeSH
- koinfekce diagnóza parazitologie veterinární MeSH
- mikrofilárie klasifikace izolace a purifikace MeSH
- nemoci psů diagnóza parazitologie MeSH
- odběr vzorku krve metody veterinární MeSH
- parazitemie diagnóza parazitologie veterinární MeSH
- psi MeSH
- studie proveditelnosti MeSH
- Triatominae * MeSH
- vény parazitologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- psi MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Saliva of blood-sucking arthropods contains a complex cocktail of pharmacologically active compounds that assists feeding by counteracting their hosts' hemostatic and inflammatory reactions. Panstrongylus megistus (Burmeister) is an important vector of Chagas disease in South America, but despite its importance there is only one salivary protein sequence publicly deposited in GenBank. In the present work, we used Illumina technology to disclose and publicly deposit 3,703 coding sequences obtained from the assembly of >70 million reads. These sequences should assist proteomic experiments aimed at identifying pharmacologically active proteins and immunological markers of vector exposure. A supplemental file of the transcriptome and deducted protein sequences can be obtained from http://exon.niaid.nih.gov/transcriptome/P_megistus/Pmeg-web.xlsx.
- MeSH
- fylogeneze MeSH
- hmyzí proteiny genetika metabolismus MeSH
- molekulární sekvence - údaje MeSH
- nymfa genetika růst a vývoj metabolismus MeSH
- Panstrongylus genetika růst a vývoj metabolismus MeSH
- proteomika MeSH
- sialoglykoproteiny genetika metabolismus MeSH
- slinné proteiny a peptidy genetika metabolismus MeSH
- sliny chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
BACKGROUND: Triatoma infestans is the main vector of Chagas disease in South America. As in all hematophagous arthropods, its saliva contains a complex cocktail that assists blood feeding by preventing platelet aggregation and blood clotting and promoting vasodilation. These salivary components can be immunologically recognized by their vector's hosts and targeted with antibodies that might disrupt blood feeding. These antibodies can be used to detect vector exposure using immunoassays. Antibodies may also contribute to the fast evolution of the salivary cocktail. METHODOLOGY: Salivary gland cDNA libraries from nymphal and adult T. infestans of breeding colonies originating from different locations (Argentina, Chile, Peru and Bolivia), and cDNA libraries originating from F1 populations of Bolivia, were sequenced using Illumina technology. Coding sequences (CDS) were extracted from the assembled reads, the numbers of reads mapped to these CDS, sequences were functionally annotated and polymorphisms determined. MAIN FINDINGS/SIGNIFICANCE: Over five thousand CDS, mostly full length or near full length, were publicly deposited on GenBank. Transcripts that were over 10-fold overexpressed from different geographical regions, or from different developmental stages were identified. Polymorphisms were mapped to derived coding sequences, and found to vary between developmental instars and geographic origin of the biological material. This expanded sialome database from T. infestans should be of assistance in future proteomic work attempting to identify salivary proteins that might be used as epidemiological markers of vector exposure, or proteins of pharmacological interest.
- MeSH
- genová knihovna * MeSH
- slinné proteiny a peptidy genetika metabolismus MeSH
- sliny chemie MeSH
- transkriptom genetika MeSH
- Triatoma genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Geografické názvy
- Jižní Amerika MeSH
BACKGROUND: Salivary proteins of Triatoma infestans elicit humoral immune responses in their vertebrate hosts. These immune responses indicate exposure to triatomines and thus can be a useful epidemiological tool to estimate triatomine infestation. In the present study, we analyzed antibody responses of guinea pigs to salivary antigens of different developmental stages of four T. infestans strains originating from domestic and/or peridomestic habitats in Argentina, Bolivia, Chile and Peru. We aimed to identify developmental stage- and strain-specific salivary antigens as potential markers of T. infestans exposure. METHODOLOGY AND PRINCIPAL FINDINGS: In SDS-PAGE analysis of salivary proteins of T. infestans the banding pattern differed between developmental stages and strains of triatomines. Phenograms constructed from the salivary profiles separated nymphal instars, especially the 5th instar, from adults. To analyze the influence of stage- and strain-specific differences in T. infestans saliva on the antibody response of guinea pigs, twenty-one guinea pigs were exposed to 5th instar nymphs and/or adults of different T. infestans strains. Western blot analyses using sera of exposed guinea pigs revealed stage- and strain-specific variations in the humoral response of animals. In total, 27 and 17 different salivary proteins reacted with guinea pig sera using IgG and IgM antibodies, respectively. Despite all variations of recognized salivary antigens, an antigen of 35 kDa reacted with sera of almost all challenged guinea pigs. CONCLUSION: Salivary antigens are increasingly considered as an epidemiological tool to measure exposure to hematophagous arthropods, but developmental stage- and strain-specific variations in the saliva composition and the respective differences of immunogenicity are often neglected. Thus, the development of a triatomine exposure marker for surveillance studies after triatomine control campaigns requires detailed investigations. Our study resulted in the identification of a potential antigen as useful marker of T. infestans exposure.
- MeSH
- biologické markery krev MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- hmyzí proteiny imunologie MeSH
- kousnutí a bodnutí imunologie MeSH
- morčata MeSH
- proteom analýza MeSH
- protilátky krev MeSH
- slinné proteiny a peptidy analýza imunologie MeSH
- Triatoma * MeSH
- western blotting MeSH
- zvířata MeSH
- Check Tag
- morčata MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Geografické názvy
- Jižní Amerika MeSH
Peptides of the adipokinetic hormone (AKH)/red pigment-concentrating hormone (RPCH) family were isolated and sequenced from the retrocerebral corpora cardiaca of four kissing bugs which are all vectors of the protozoan Trypanosoma cruzi responsible for Chagas' disease. The sequence of three novel AKHs were deduced from the multiple MS(N) electrospray mass data: the octapeptide pGlu-Leu-Thr-Phe-Ser-Thr-Asp-Trp amide (denoted Rhopr-AKH) in Rhodnius prolixus and Panstrongylus megistus, the nonapeptide pGlu-Leu-Thr-Phe-Thr-Pro-Asn-Trp-Gly amide (denoted Triin-AKH) in Triatoma infestans and the decapeptide pGlu-Leu-Thr-Phe-Ser-Asp-Gly-Trp-Gly-Asn amide (denoted Dipma-AKH) in Dipetalogaster maxima. The sequences were confirmed by identical behavior of natural and synthetic forms in reversed-phase HPLC and by CID-MS mass spectra. Conspecific injections of a dose of 10 pmol of the respective synthetic peptides resulted in a small but significant increase of the lipid concentration in the hemolymph. These experiments suggest that AKHs in kissing bugs act to regulate lipid metabolism, possibly during dispersal flights which is one of the mechanisms whereby the insects reach new outbreak areas. Copyright © 2012 Elsevier Inc. All rights reserved.
- MeSH
- hemolymfa metabolismus MeSH
- hmyzí hormony MeSH
- kobylky metabolismus účinky léků MeSH
- kyselina pyrrolidonkarboxylová * MeSH
- metabolismus lipidů MeSH
- oligopeptidy MeSH
- Panstrongylus * metabolismus MeSH
- Rhodnius * metabolismus MeSH
- sekvence aminokyselin MeSH
- sekvenční analýza proteinů MeSH
- Triatoma * metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
Insecticide-impregnated nets can kill triatomine bugs, but it remains unclear whether they can protect against Chagas disease transmission. In a field trial in Quequeña, Peru, sentinel guinea pigs placed in intervention enclosures covered by deltamethrin-treated nets showed significantly lower antibody responses to saliva of Triatoma infestans compared with animals placed in pre-existing control enclosures. Our results strongly suggest that insecticide-treated nets prevent triatomine bites and can thereby protect against infection with Trypanosoma cruzi. Anti-salivary immunoassays are powerful new tools to evaluate intervention strategies against Chagas disease.
- MeSH
- Chagasova nemoc prevence a kontrola MeSH
- dezinsekce metody MeSH
- imunoanalýza MeSH
- kousnutí a bodnutí hmyzem imunologie prevence a kontrola MeSH
- morčata MeSH
- parazitologie metody MeSH
- sítě nad lůžka napuštěné insekticidy MeSH
- sliny imunologie MeSH
- Triatoma imunologie MeSH
- zvířata MeSH
- Check Tag
- morčata MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Geografické názvy
- Peru MeSH
