Most cited article - PubMed ID 26466163
Host-specificity of Monoxenous Trypanosomatids: Statistical Analysis of the Distribution and Transmission Patterns of the Parasites from Neotropical Heteroptera
Trypanosomatids are obligate parasites of animals, predominantly insects and vertebrates, and flowering plants. Monoxenous species, representing the vast majority of trypanosomatid diversity, develop in a single host, whereas dixenous species cycle between two hosts, of which primarily insect serves as a vector. To explore in-depth the diversity of insect trypanosomatids including their co-infections, sequence profiling of their 18S rRNA gene was used for true bugs (Hemiptera; 18% infection rate) and flies (Diptera; 10%) in Cuba. Out of 48 species (molecular operational taxonomic units) belonging to the genera Vickermania (16 spp.), Blastocrithidia (7), Obscuromonas (4), Phytomonas (5), Leptomonas/Crithidia (5), Herpetomonas (5), Wallacemonas (2), Kentomonas (1), Angomonas (1) and two unnamed genera (1 + 1), 38 species have been encountered for the first time. The detected Wallacemonas and Angomonas species constitute the most basal lineages of their respective genera, while Vickermania emerged as the most diverse group. The finding of Leptomonas seymouri, which is known to rarely infect humans, confirms that Dysdercus bugs are its natural hosts. A clear association of Phytomonas with the heteropteran family Pentatomidae hints at its narrow host association with the insect rather than plant hosts. With a focus on multiple infections of a single fly host, using deep Nanopore sequencing of 18S rRNA, we have identified co-infections with up to 8 trypanosomatid species. The fly midgut was usually occupied by several Vickermania species, while Herpetomonas and/or Kentomonas species prevailed in the hindgut. Metabarcoding was instrumental for analysing extensive co-infections and also allowed the identification of trypanosomatid lineages and genera.
- Keywords
- biodiversity, diptera, heteroptera, host specificity, monoxenous trypanosomatids, multiple infections, nanopore sequencing, phylogeny, systematics,
- MeSH
- Diptera genetics MeSH
- Phylogeny * MeSH
- Hemiptera parasitology genetics MeSH
- Coinfection * parasitology MeSH
- DNA, Protozoan genetics analysis MeSH
- RNA, Ribosomal, 18S * genetics analysis MeSH
- Trypanosomatina * genetics classification isolation & purification MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Cuba epidemiology MeSH
- Names of Substances
- DNA, Protozoan MeSH
- RNA, Ribosomal, 18S * MeSH
In this work, we investigated parasites of the firebug Pyrrhocoris apterus in Austria and demonstrated that in addition to the extensively studied Leptomonas pyrrhocoris, it can also be infected by Blastocrithidia sp. and by a mermithid, which for the first time has been characterized using molecular methods. This diversity can be explained by the gregarious lifestyle, as well as the coprophagous and cannibalistic behavior of the insect hosts that makes them susceptible to various parasites. In addition, we showed no tight association of the L. pyrrhocoris haplotypes and geographical locations (at least, considering the relatively small scale of locations in Austria) implying that the natural populations of L. pyrrhocoris are mixed due to the mobility of their firebug hosts.
- Keywords
- Blastocrithidia, Firebugs, Mermithidae, Pyrrhocoris apterus,
- MeSH
- Heteroptera * parasitology MeSH
- Parasites * MeSH
- Trypanosomatina * MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Austria MeSH
Monoxenous (insect-restricted) trypanosomatids are highly diverse and abundant in nature. While many papers focus on the taxonomy and distribution of these parasites, studies on their biology are still scarce. In particular, this concerns trypanosomatids inhabiting the ubiquitous mosquitoes. To shed light on the circulation of monoxenous trypanosomatids with the participation of mosquitoes, we performed a multifaceted study combining the examination of naturally- and experimentally-infected insects using light and electron microscopy and molecular identification of parasites. Our examination of overwintering mosquitoes (genera Culex and Culiseta) revealed that their guts contained living trypanosomatids, which can be spread during the next season. Experimental infections with Crithidia spp. demonstrated that imagines represent permissive hosts, while larvae are resistant to these parasites. We argue that for the parasites with wide specificity, mosquitoes act as facultative hosts. Other trypanosomatids may have specific adaptations for vertical transmission in these insects at the expense of their potential to infect a wider range of hosts and, consequently, abundance in nature.
- Keywords
- Crithidia, Paratrypanosoma, Trypanosomatidae, experimental infection, facultative host, overwintering mosquitoes, prevalence, specificity, transmission,
- Publication type
- Journal Article MeSH
In this work, we describe the first Leishmania-infecting leishbunyavirus-the first virus other than Leishmania RNA virus (LRV) found in trypanosomatid parasites. Its host is Leishmaniamartiniquensis, a human pathogen causing infections with a wide range of manifestations from asymptomatic to severe visceral disease. This virus (LmarLBV1) possesses many characteristic features of leishbunyaviruses, such as tripartite organization of its RNA genome, with ORFs encoding RNA-dependent RNA polymerase, surface glycoprotein, and nucleoprotein on L, M, and S segments, respectively. Our phylogenetic analyses suggest that LmarLBV1 originated from leishbunyaviruses of monoxenous trypanosomatids and, probably, is a result of genomic re-assortment. The LmarLBV1 facilitates parasites' infectivity in vitro in primary murine macrophages model. The discovery of a virus in L.martiniquensis poses the question of whether it influences pathogenicity of this parasite in vivo, similarly to the LRV in other Leishmania species.
- Keywords
- Bunyavirales, Leishmania martiniquensis, leishbunyavirus,
- MeSH
- Phylogeny * MeSH
- Genome, Viral * MeSH
- Leishmania pathogenicity virology MeSH
- Macrophages parasitology MeSH
- Mice MeSH
- Open Reading Frames MeSH
- Reassortant Viruses MeSH
- RNA-Dependent RNA Polymerase MeSH
- RNA Viruses classification genetics MeSH
- High-Throughput Nucleotide Sequencing MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- RNA-Dependent RNA Polymerase MeSH
In this work, we analyzed viral prevalence in trypanosomatid parasites (Blechomonas spp.) infecting Siphonaptera and discovered nine species of viruses from three different groups (leishbunyaviruses, narnaviruses, and leishmaniaviruses). Most of the flagellate isolates bore two or three viral types (mixed infections). Although no new viral groups were documented in Blechomonas spp., our findings are important for the comprehension of viral evolution. The discovery of bunyaviruses in blechomonads was anticipated, since these viruses have envelopes facilitating their interspecific transmission and have already been found in various trypanosomatids and metatranscriptomes with trypanosomatid signatures. In this work, we also provided evidence that even representatives of the family Narnaviridae are capable of host switching and evidently have accomplished switches multiple times in the course of their evolution. The most unexpected finding was the presence of leishmaniaviruses, a group previously solely confined to the human pathogens Leishmania spp. From phylogenetic inferences and analyses of the life cycles of Leishmania and Blechomonas, we concluded that a common ancestor of leishmaniaviruses most likely infected Leishmania first and was acquired by Blechomonas by horizontal transfer. Our findings demonstrate that evolution of leishmaniaviruses is more complex than previously thought and includes occasional host switching.IMPORTANCE Flagellates belonging to the genus Leishmania are important human parasites. Some strains of different Leishmania species harbor viruses (leishmaniaviruses), which facilitate metastatic spread of the parasites, thus aggravating the disease. Up until now, these viruses were known to be hosted only by Leishmania Here, we analyzed viral distribution in Blechomonas, a related group of flagellates parasitizing fleas, and revealed that they also bear leishmaniaviruses. Our findings shed light on the entangled evolution of these viruses. In addition, we documented that Blechomonas can be also infected by leishbunyaviruses and narnaviruses, viral groups known from other insects' flagellates.
- Keywords
- Blechomonas, Leishbunyaviridae, Leishmaniavirus, Narnaviridae,
- MeSH
- Phylogeny MeSH
- Genetic Variation MeSH
- Genome, Viral MeSH
- Leishmaniavirus genetics MeSH
- Evolution, Molecular * MeSH
- RNA Viruses classification isolation & purification MeSH
- Siphonaptera parasitology MeSH
- Trypanosomatina virology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Blastocrithidia papi is a unique trypanosomatid in that its life cycle is synchronized with that of its host, and includes an obligate stage of development in Malpighian tubules (MTs). This occurs in firebugs, which exited the winter diapause. In the short period, preceding the mating of overwintered insects, the flagellates penetrate MTs of the host, multiply attached to the epithelial surface with their flagella, and start forming cyst-like amastigotes (CLAs) in large agglomerates. By the moment of oviposition, a large number of CLAs are already available in the rectum. They are discharged on the eggs' surface with feces, used for transmission of bugs' symbiotic bacteria, which are compulsorily engulfed by the newly hatched nymphs along with the CLAs. The obligate development of B. papi in MTs is definitely linked to the life cycle synchronization. The absence of peristalsis allow the trypanosomatids to accumulate and form dense CLA-forming subpopulations, whereas the lack of peritrophic structures facilitates the extensive discharge of CLAs directly into the hindgut lumen. The massive release of CLAs associated with oviposition is indispensable for maximization of the infection efficiency at the most favorable time point.
- MeSH
- Epithelial Cells parasitology ultrastructure MeSH
- Feces parasitology MeSH
- Hemiptera parasitology ultrastructure MeSH
- Host-Pathogen Interactions * MeSH
- Oviposition MeSH
- Malpighian Tubules parasitology ultrastructure MeSH
- Life Cycle Stages MeSH
- Intestines parasitology ultrastructure MeSH
- Trypanosomatina growth & development ultrastructure MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Trypanosomatid flagellates have not been studied in Austria in any detail. In this study, specific nested PCR, targeted on the ribosomal small subunit, was used to determine the occurrence and diversity of trypanosomatids in wild-caught mosquitoes sampled across Eastern Austria in the years 2014-2015. We collected a total of 29,975 mosquitoes of 19 species divided in 1680 pools. Of these, 298 (17.7%), representing 12 different mosquito species, were positive for trypanosomatid DNA. In total, seven trypanosomatid spp. were identified (three Trypanosoma, three Crithidia and one Herpetomonas species), with the highest parasite species diversity found in the mosquito host Coquillettidia richiardii. The most frequent parasite species belonged to the mammalian Trypanosoma theileri/cervi species complex (found in 105 pools; 6.3%). The avian species T. culicavium (found in 69 pools; 4.1%) was only detected in mosquitoes of the genus Culex, which corresponds to their preference for avian hosts. Monoxenous trypanosomatids of the genus Crithidia and Herpetomonas were found in 20 (1.3%) mosquito pools. One third (n = 98) of the trypanosomatid positive mosquito pools carried more than one parasite species. This is the first large scale study of trypanosomatid parasites in Austrian mosquitoes and our results are valuable in providing an overview of the diversity of these parasites in Austria.
- MeSH
- Biodiversity MeSH
- Culicidae parasitology MeSH
- Phylogeny MeSH
- DNA, Protozoan MeSH
- DNA, Ribosomal MeSH
- Sequence Analysis, DNA MeSH
- Trypanosoma classification genetics MeSH
- Trypanosomiasis parasitology transmission MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Austria MeSH
- Names of Substances
- DNA, Protozoan MeSH
- DNA, Ribosomal MeSH
BACKGROUND: Leptomonas pyrrhocoris is a parasite of the firebug Pyrrhocoris apterus. This flagellate has been recently proposed as a model species for studying different aspects of the biology of monoxenous trypanosomatids, including host - parasite interactions. During its life cycle L. pyrrhocoris never tightly attaches to the epithelium of the insect gut. In contrast, its dixenous relatives (Leishmania spp.) establish a stable infection via attachment to the intestinal walls of their insect hosts. MATERIAL AND METHODS: This process is mediated by chemical modifications of the cell surface lipophosphoglycans. In our study we tested whether the inability of L. pyrrhocoris to attach to the firebug's midgut is associated with the absence of these glycoconjugates. We also analyzed evolution of the proteins involved in proper lipophosphoglycan assembly, cell attachment and establishment of a stable infection in L. pyrrhocoris, L. seymouri, and Leishmania spp. Our comparative analysis demonstrated differences in SCG/L/R repertoire between the two parasite subgenera, Leishmania and Viannia, which may be related to distinct life strategies in various Leishmania spp. The genome of L. pyrrhocoris encodes 6 SCG genes, all of which are quite divergent from their orthologs in the genus Leishmania. Using direct probing with an antibody recognizing the β-Gal side chains of lipophosphoglycans, we confirmed that these structures are not synthesized in L. pyrrhocoris. CONCLUSION: We conclude that either the SCG enzymes are not active in this species (similarly to SCG5/7 in L. major), or they possess a different biochemical activity.
- Keywords
- Host-parasite interaction, Insect gut's attachment, L. pyrrhocoris, LPG, Monoxenous trypanosomatids, SCG enzymes,
- Publication type
- Journal Article MeSH
- Review MeSH
In the present work, we investigated molecular mechanisms governing thermal resistance of a monoxenous trypanosomatid Crithidia luciliae thermophila, which we reclassified as a separate species C. thermophila. We analyzed morphology, growth kinetics, and transcriptomic profiles of flagellates cultivated at low (23°C) and elevated (34°C) temperature. When maintained at high temperature, they grew significantly faster, became shorter, with genes involved in sugar metabolism and mitochondrial stress protection significantly upregulated. Comparison with another thermoresistant monoxenous trypanosomatid, Leptomonas seymouri, revealed dramatic differences in transcription profiles of the two species with only few genes showing the same expression pattern. This disparity illustrates differences in the biology of these two parasites and distinct mechanisms of their thermotolerance, a prerequisite for living in warm-blooded vertebrates.
- MeSH
- Biochemical Phenomena genetics MeSH
- Crithidia genetics MeSH
- Gene Expression genetics MeSH
- Insecta genetics MeSH
- Temperature MeSH
- Transcriptome genetics MeSH
- Up-Regulation genetics MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
UNLABELLED: We describe a novel symbiotic association between a kinetoplastid protist, Novymonas esmeraldas gen. nov., sp. nov., and an intracytoplasmic bacterium, "Candidatus Pandoraea novymonadis" sp. nov., discovered as a result of a broad-scale survey of insect trypanosomatid biodiversity in Ecuador. We characterize this association by describing the morphology of both organisms, as well as their interactions, and by establishing their phylogenetic affinities. Importantly, neither partner is closely related to other known organisms previously implicated in eukaryote-bacterial symbiosis. This symbiotic association seems to be relatively recent, as the host does not exert a stringent control over the number of bacteria harbored in its cytoplasm. We argue that this unique relationship may represent a suitable model for studying the initial stages of establishment of endosymbiosis between a single-cellular eukaryote and a prokaryote. Based on phylogenetic analyses, Novymonas could be considered a proxy for the insect-only ancestor of the dixenous genus Leishmania and shed light on the origin of the two-host life cycle within the subfamily Leishmaniinae. IMPORTANCE: The parasitic trypanosomatid protist Novymonas esmeraldas gen. nov., sp. nov. entered into endosymbiosis with the bacterium "Ca. Pandoraea novymonadis" sp. nov. This novel and rather unstable interaction shows several signs of relatively recent establishment, qualifying it as a potentially unique transient stage in the increasingly complex range of eukaryotic-prokaryotic relationships.
