RESUMEN
The phylum Parabasalia includes very diverse single-cell organisms that nevertheless share a distinctive set of morphological traits. Most are harmless or beneficial gut symbionts of animals, but some have turned into parasites in other body compartments, the most notorious example being Trichomonas vaginalis in humans. Parabasalians have garnered attention for their nutritional symbioses with termites, their modified anaerobic mitochondria (hydrogenosomes), their character evolution, and the wholly unique features of some species. The molecular revolution confirmed the monophyly of Parabasalia, but considerably changed our view of their internal relationships, prompting a comprehensive reclassification 14 years ago. This classification has remained authoritative for many subgroups despite a greatly expanded pool of available data, but the large number of species and sequences that have since come out allow for taxonomic refinements in certain lineages, which we undertake here. We aimed to introduce as little disruption as possible but at the same time ensure that most taxa are truly monophyletic, and that the larger clades are subdivided into meaningful units. In doing so, we also highlighted correlations between the phylogeny of parabasalians and that of their hosts.
Asunto(s)
Filogenia , Animales , Parabasalidea/clasificación , Parabasalidea/genética , SimbiosisRESUMEN
Cristamonadea is a large class of parabasalian protists that reside in the hindguts of wood-feeding insects, where they play an essential role in the digestion of lignocellulose. This group of symbionts boasts an impressive array of complex morphological characteristics, many of which have evolved multiple times independently. However, their diversity is understudied and molecular data remain scarce. Here we describe seven new species of cristamonad symbionts from Comatermes, Calcaritermes, and Rugitermes termites from Peru and Ecuador. To classify these new species, we examined cells by light and scanning electron microscopy, sequenced the symbiont small subunit ribosomal RNA (rRNA) genes, and carried out barcoding of the mitochondrial large subunit rRNA gene of the hosts to confirm host identification. Based on these data, five of the symbionts characterized here represent new species within described genera: Devescovina sapara n. sp., Devescovina aymara n. sp., Macrotrichomonas ashaninka n. sp., Macrotrichomonas secoya n. sp., and Macrotrichomonas yanesha n. sp. Additionally, two symbionts with overall morphological characteristics similar to the poorly-studied and probably polyphyletic 'joeniid' Parabasalia are classified in a new genus Runanympha n. gen.: Runanympha illapa n. sp., and Runanympha pacha n. sp.
Asunto(s)
Isópteros , Parabasalidea , Simbiosis , Animales , Parabasalidea/clasificación , Parabasalidea/fisiologíaRESUMEN
The desert dampwood termite Paraneotermes simplicicornis harbors several species of obligately symbiotic protists that support its nutrition by fermenting lignocellulose. Among them are three morphotypes with the dexiotropic spiraling flagellar bands characteristic of Spirotrichonymphea (Parabasalia). The largest morphotype, characterized by an elongated cell apex with axial columella and internally positioned spiraling flagellar bands, was previously described as Spirotrichonympha polygyra. A smaller morphotype, with similarly internalized flagellar bands but a more rounded posterior without a protruding axostyle, was previously reported but not named. The smallest morphotype has surface flagellar bands and can attach to other protist cells by its apex. In this study, we combine light microscopy of live specimens and 18S rRNA gene sequencing of individually isolated cells to better understand the diversity of symbionts in P. simplicicornis. We found that S. polygyra branches distantly from true Spirotrichonympha, which are associated with Reticulitermes termites. Thus, we propose the new genus Cuppa to accommodate C. polygyra n. comb. (type species) and the similar but smaller morphotype Cuppa taenia n. sp. The undescribed smallest morphotype can be excluded from all previously described Spirotrichonymphea genera by molecular and behavioral evidence, so we propose Fraterculus simplicicornis n. gen., n. sp., to accommodate this organism.
Asunto(s)
Isópteros/parasitología , Parabasalidea/clasificación , Parabasalidea/fisiología , Simbiosis , Animales , ADN Protozoario/genética , Parabasalidea/genética , Filogenia , ARN Ribosómico 18S/genética , Especificidad de la EspecieRESUMEN
Coptotermes formosanus Shiraki and Coptotermes gestroi (Wasmann) (Blattoidea: Rhinotermitidae) are invasive subterranean termite pest species with a major global economic impact. However, the descriptions of the mutualistic protist communities harbored in their respective hindguts remain fragmentary. The C. formosanus hindgut has long been considered to harbor three protist species, Pseudotrichonympha grassii (Trichonymphida), Holomastigotoides hartmanni, and Cononympha (Spirotrichonympha) leidyi (Spirotrichonymphida), but molecular data have suggested that the diversity may be higher. Meanwhile, the C. gestroi community remains undescribed except for Pseudotrichonympha leei. To complete the characterization of these communities, hindguts of workers from both termite species were investigated using single-cell PCR, microscopy, cell counts, and 18S rRNA amplicon sequencing. The two hosts were found to harbor intriguingly parallel protist communities, each consisting of one Pseudotrichonympha species, two Holomastigotoides species, and two Cononympha species. All protist species were unique to their respective hosts, which last shared a common ancestor ~18 MYA. The relative abundances of protist species in each hindgut differed remarkably between cell count data and 18S rRNA profiles, calling for caution in interpreting species abundances from amplicon data. This study will enable future research in C. formosanus and C. gestroi hybrids, which provide a unique opportunity to study protist community inheritance, compatibility, and potential contribution to hybrid vigor.
Asunto(s)
Sistema Digestivo/parasitología , Isópteros/parasitología , Parabasalidea/clasificación , Parabasalidea/genética , Animales , ADN Protozoario/genética , Interacciones Huésped-Parásitos , Filogenia , Reacción en Cadena de la Polimerasa , ARN Ribosómico 18S/genética , Análisis de la Célula Individual , SimbiosisRESUMEN
Hoplonympha natator is an obligate symbiont of Paraneotermes simplicicornis (Kalotermitidae), from southwestern North America. Another Hoplonympha species inhabits Hodotermopsis sjostedti (Archotermopsidae), from montane Southeast Asia. The large phylogenetic and geographical distance between the hosts makes the distribution of Hoplonympha puzzling. Here, we report the phylogenetic position of H. natator from P. simplicicornis through maximum likelihood and Bayesian analysis of 18S rRNA genes. The two Hoplonympha species form a clade with a deep node, making a recent symbiont transfer unlikely. The distribution of Hoplonympha may be due to an ancient transfer or strict vertical inheritance with differential loss from other hosts.
Asunto(s)
Isópteros/parasitología , Parabasalidea/clasificación , Animales , Arizona , Teorema de Bayes , Parabasalidea/genética , Filogenia , ARN Protozoario/análisis , ARN Ribosómico 18S/análisis , Especificidad de la Especie , SimbiosisRESUMEN
Holomastigotes is a protist genus (Parabasalia: Spirotrichonymphea) that resides in the hindguts of "lower" termites. It can be distinguished from other parabasalids by spiral flagellar bands that run along the entire length of the cell, an anterior nucleus, a reduced or absent axostyle, the presence of spherical vesicles inside the cells, and the absence of ingested wood particles. Eight species have been described based on their morphology so far, although no molecular data were available prior to this study. We determined the 18S rRNA gene sequences of Holomastigotes from the hindguts of Hodotermopsis sjostedti, Reticulitermes flavipes, Reticulitermes lucifugus, and Reticulitermes tibialis. Phylogenetic analyses placed all sequences in an exclusive and well-supported clade with the type species, Holomastigotes elongatum from R. lucifugus. However, the phylogenetic position of Holomastigotes within the Spirotrichonymphea was not resolved. We describe two new species, Holomastigotes flavipes n. sp. and Holomastigotes tibialis n. sp., inhabiting the hindguts of R. flavipes and R. tibialis, respectively.
Asunto(s)
Isópteros/parasitología , Parabasalidea/clasificación , Animales , Sistema Digestivo/parasitología , Parabasalidea/citología , Parabasalidea/genética , Filogenia , ARN Protozoario/análisis , ARN Ribosómico 18S/análisis , SimbiosisRESUMEN
Termites are global pests and can cause serious damage to buildings, crops, and plantation forests. The symbiotic intestinal flora plays an important role in the digestion of cellulose and nitrogen in the life of termites. Termites and their symbiotic microbes in the gut form a synergistic system. These organism work together to digest lignocellulose to make the termites grow on nitrogen deficient food. In this paper, the diversity of symbiotic microorganisms in the gut of termites, including protozoan, spirochetes, actinomycetes, fungus and bacteria, and their role in the digestion of lignocellulose and also the biotechnological applications of these symbiotic microorganisms are discussed. The high efficiency lignocellulose degradation systems of symbiotic microbes in termite gut not only provided a new way of biological energy development, but also has immense prospect in the application of cellulase enzymes. In addition, the study on the symbiotic microorganisms in the gut of termites will also provide a new method for the biological control of termites by the endophytic bacteria in the gut of termites.
Asunto(s)
Bacterias/metabolismo , Biodiversidad , Biotecnología/métodos , Hongos/metabolismo , Isópteros/microbiología , Oxymonadida/metabolismo , Parabasalidea/metabolismo , Animales , Bacterias/clasificación , Bacterias/crecimiento & desarrollo , Hongos/clasificación , Hongos/crecimiento & desarrollo , Intestinos/microbiología , Intestinos/parasitología , Isópteros/parasitología , Lignina/metabolismo , Oxymonadida/clasificación , Oxymonadida/crecimiento & desarrollo , Parabasalidea/clasificación , Parabasalidea/crecimiento & desarrollo , SimbiosisRESUMEN
The guts of lower termites are inhabited by host-specific consortia of cellulose-digesting flagellate protists. In this first investigation of the symbionts of the family Serritermitidae, we found that Glossotermes oculatus and Serritermes serrifer each harbor similar parabasalid morphotypes: large Pseudotrichonympha-like cells, medium-sized Leptospironympha-like cells with spiraled bands of flagella, and small Hexamastix-like cells; oxymonadid flagellates were absent. Despite their morphological resemblance to Pseudotrichonympha and Leptospironympha, a SSU rRNA-based phylogenetic analysis identified the two larger, trichonymphid flagellates as deep-branching sister groups of Teranymphidae, with Leptospironympha sp. (the only spirotrichosomid with sequence data) in a moderately supported basal position. Only the Hexamastix-like flagellates are closely related to trichomonadid flagellates from Rhinotermitidae. The presence of two deep-branching lineages of trichonymphid flagellates in Serritermitidae and the absence of all taxa characteristic of the ancestral rhinotermitids underscores that the flagellate assemblages in the hindguts of lower termites were shaped not only by a progressive loss of flagellates during vertical inheritance but also by occasional transfaunation events, where flagellates were transferred horizontally between members of different termite families. In addition to the molecular phylogenetic analyses, we present a detailed morphological characterization of the new spirotrichosomid genus Heliconympha using light and electron microscopy.
Asunto(s)
Microbioma Gastrointestinal , Isópteros/parasitología , Parabasalidea/clasificación , Animales , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Parabasalidea/citología , Parabasalidea/genética , Parabasalidea/ultraestructura , ARN Protozoario/análisis , ARN Ribosómico/análisisRESUMEN
Spirotrichonymphea is a class of hypermastigote parabasalids defined by their spiral rows of many flagella. They are obligate hindgut symbionts of lower termites. Despite more than 100 yr of morphological and ultrastructural study, the group remains poorly characterised by molecular data and the phylogenetic positions and taxonomic validity of most genera remain in question. The genus Spirotrichonympha has been reported to inhabit several termite genera, including Reticulitermes, Coptotermes, and Hodotermopsis. The type species for this genus, Spirotrichonympha flagellata, was described from Reticulitermes lucifugus but no molecular data are yet available for this species. In this study, three new Spirotrichonympha species are described from three species of Reticulitermes. Their molecular phylogenetic position indicates that the genus is not monophyletic, as Spirotrichonympha species from Coptotermes, Paraneotermes, and Hodotermopsis branch separately. In contrast, the genus Holomastigotoides is monophyletic, as demonstrated using new sequences from Holomastigotoides species. The presence of Holomastigotoides in Prorhinotermes and the distinct phylogenetic positions of Spirotrichonympha from Reticulitermes and Coptotermes are consistent with a previously proposed symbiont fauna replacement in the ancestor of Reticulitermes.
Asunto(s)
Isópteros/microbiología , Parabasalidea/clasificación , Parabasalidea/citología , Parabasalidea/ultraestructura , Animales , Sistema Digestivo/microbiología , Filogenia , Análisis de Secuencia de ADN , Especificidad de la Especie , SimbiosisRESUMEN
Pseudotrichonympha is a large and structurally complex genus of parabasalian protists that play a key role in the digestion of lignocellulose in the termite hindgut. Like many termite symbionts, it has a conspicuous body plan that makes genus-level identification relatively easy, but species-level diversity of Pseudotrichonympha is understudied. Molecular surveys have suggested the diversity is much greater than the current number of described species, and that many "species" described in multiple hosts are in fact different, but gene sequences from formally described species remain a rarity. Here we describe three new species from Coptotermes and Prorhinotermes hosts, including small subunit ribosomal RNA (SSU rRNA) sequences from single cells. Based on host identification by morphology and DNA barcoding, as well as the morphology and phylogenetic position of each symbiont, all three represent new Pseudotrichonympha species: P. leei, P. lifesoni, and P. pearti. Pseudotrichonympha leei and P. lifesoni, both from Coptotermes, are closely related to other Coptotermes symbionts including the type species, P. hertwigi. Pseudotrichonympha pearti is the outlier of the trio, more distantly related to P. leei and P. lifesoni than they are to one another, and contains unique features, including an unusual rotating intracellular structure of unknown function.
Asunto(s)
Parabasalidea/clasificación , Parabasalidea/citología , Animales , Genes Protozoarios , Isópteros/parasitología , Microscopía , Parabasalidea/fisiología , Filogenia , ARN Ribosómico/genéticaRESUMEN
The subterranean termite Heterotermes aureus is endemic to arid regions of southwestern USA and northern Mexico. Like other termites in the family Rhinotermitidae, it harbors a community of protists (Phylum Parabasalia) in its hindgut that aid in cellulose digestion. We investigated the hindgut community of H. aureus using light microscopy, single cell isolation, and high throughput amplicon sequencing. Here we describe four new parabasalid species from the classes Trichonymphea and Spirotrichonymphea. Three of the new species include Pseudotrichonympha aurea (Trichonymphea), Holomastigotoides aureus, and Holomastigotoides oxyrhynchus (Spirotrichonymphea). The fourth new species is a Spirotrichonympha-like protist for which we reinstate the genus Cononympha and describe under the name Cononympha aurea (Spirotrichonymphea). We also used high throughput amplicon sequencing with custom primers on DNA from fresh and ethanol preserved termites collected across the southwest USA and Mexico to investigate population-level differences in hindgut community composition. We report that the community is highly similar across populations: no additional parabasalid species were identified in any of the H. aureus specimens, but several specimens appeared to lack either C. aurea or H. oxyrhynchus.
Asunto(s)
Isópteros/parasitología , Filogenia , Animales , Intestinos/parasitología , México , Parabasalidea/clasificación , Parabasalidea/citología , Parabasalidea/genética , Sudoeste de Estados Unidos , Especificidad de la Especie , SimbiosisRESUMEN
Bronchopulmonary lophomoniasis (BPL) is an emerging disease of potential importance. BPL is presented by non-specific clinical picture and is usually accompanied by immunosuppression. Culture of Lophomonas blattarum is difficult and its molecular diagnosis has not yet been developed. Therefore, microscopic examination of respiratory samples, e.g., bronchoalveolar lavage (BAL) or sputum, is the mainstay of BPL diagnosis. Creola bodies and ciliocytophthoria are two forms of bronchial cells which occur in chest diseases with non-specific clinical picture like that of BPL. Both forms could be misrecognized as multi-flagellates because of their motile cilia in the wet mounts and due to shape variability of L. blattarum in stained smears. The aim of the study is to compare different staining techniques for visualizing L. blattarum to improve the recognition and diagnosis of BPL, to distinguish respiratory epithelial cells from L. blattarum and to decide which stain is recommended in suspected cases of BPL. BAL samples from patients which contain L. blattarum, creola bodies, and ciliocytophthoria were collected then wet mounts were examined. The BAL samples were also stained by Papanicolaou (PAP), Giemsa, hematoxylin and eosin (H & E), trichrome, Gram, and Diff-Quik (DQ) stains. The different staining techniques were compared regarding the stain quality. In wet mounts, the ciliary movement was coordinate and synchronous while the flagellar movement was wavy and leaded to active swimming of L. blattarum. In stained slides, bronchial cells were characterized by the presence of basal nucleus and the terminal bar from which the cilia arise. Trichrome was the best stain in demonstration of cellular details of L. blattarum. H & E, PAP, and Giemsa stains showed good quality of stains. Gram and DQ stains showed only pale hues of L. blattarum. We recommended adding Wheatley's trichrome staining to the differential diagnosis workup of cases of non-specific chest infections, especially when BPL is suspected, to avoid overdiagnosis or underdiagnosis of it.
Asunto(s)
Enfermedades Pulmonares/diagnóstico , Enfermedades Pulmonares/parasitología , Parabasalidea/aislamiento & purificación , Infecciones por Protozoos/diagnóstico , Coloración y Etiquetado/métodos , Animales , Parabasalidea/clasificación , Infecciones por Protozoos/parasitologíaRESUMEN
The genus HypotrichomonasLee, 1960 belongs to the small parabasalian class Hypotrichomonadea. Although five Hypotrichomonas species have been described from intestines of lizards and birds, some descriptions were brief and incomplete. Only the type species H. acosta has been observed repeatedly. We have established 23 strains of the genus Hypotrichomonas in culture. Phylogenetic and morphological analyses showed that these isolates represent eight distinct species, six of which are novel. Three of the species showed unusual morphology, such as a reduced undulating membrane, absence of the free part of the recurrent flagellum or a costa-like fiber. Our strains were isolated from a wide range of hosts including cockroaches, frogs, tortoises, lizards, snakes, marsupials, pigs, rodents, and primates. The genus Hypotrichomonas thus contains a relatively large number of species that differ in morphology, phylogenetic position and host range. It is remarkable that such diversity of hypotrichomonads was previously undetected, although a number of studies dealt with intestinal trichomonads of vertebrates and invertebrates. Our results indicate that the diversity of the genus Hypotrichomonas as well as of the whole Parabasalia is still only poorly understood, and the lineages described so far likely represent only a small fraction of the true diversity of parabasalids.
Asunto(s)
Variación Genética , Parabasalidea/citología , Parabasalidea/genética , Filogenia , Animales , Biodiversidad , ADN Protozoario/genética , Datos de Secuencia Molecular , Parabasalidea/clasificación , ARN Ribosómico 18S/genética , Especificidad de la EspecieRESUMEN
Macrotrichomonas (Cristamonadea: Parabasalia) is an anaerobic, amitochondriate flagellate symbiont of termite hindguts. It is noteworthy for being large but not structurally complex compared with other large parabasalians, and for retaining a structure similar in appearance to the undulating membrane (UM) of small flagellates closely related to cristamonads, e.g. Tritrichomonas. Here, we have characterised the SSU rDNA from two species described as Macrotrichomonas: M. restis Kirby 1942 from Neotermes jouteli and M. lighti Connell 1932 from Paraneotermes simplicicornis. These species do not form a clade: M. lighti branches with previously characterised Macrotrichomonas sequences from Glyptotermes, while M. restis branches with the genus Metadevescovina. We examined the M. restis UM by light microscopy, scanning electron microscopy, and transmission electron microscopy, and we find common characteristics with the proximal portion of the robust recurrent flagellum of devescovinids. Altogether, we show the genus Macrotrichomonas to be polyphyletic and propose transferring M. restis to a new genus, Macrotrichomonoides. We also hypothesise that the macrotrichomonad body plan represents the ancestral state of cristamonads, from which other major forms evolved.
Asunto(s)
ADN Protozoario/genética , Isópteros/parasitología , Parabasalidea/clasificación , Parabasalidea/genética , Animales , ADN Ribosómico/genética , Genes de ARNr , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Parabasalidea/citología , Filogenia , SimbiosisRESUMEN
The hindguts of lower termites and Cryptocercus cockroaches are home to a distinct community of archaea, bacteria, and protists (primarily parabasalids and some oxymonads). Within a host species, the composition of these hindgut communities appears relatively stable, but the evolutionary and ecological factors structuring community composition and stability are poorly understood, as are differential impacts of these factors on protists, bacteria, and archaea. We analyzed the microbial composition of parabasalids and bacteria in the hindguts of Cryptocercus punctulatus and 23 species spanning 4 families of lower termites by pyrosequencing variable regions of the small-subunit rRNA gene. Especially for the parabasalids, these data revealed undiscovered taxa and provided a phylogenetic basis for a more accurate understanding of diversity, diversification, and community composition. The composition of the parabasalid communities was found to be strongly structured by the phylogeny of their hosts, indicating the importance of historical effects, although exceptions were also identified. Particularly, spirotrichonymphids and trichonymphids likely were transferred between host lineages. In contrast, host phylogeny was not sufficient to explain the majority of bacterial community composition, but the compositions of the Bacteroidetes, Elusimicrobia, Tenericutes, Spirochaetes, and Synergistes were structured by host phylogeny perhaps due to their symbiotic associations with protists. All together, historical effects probably resulting from vertical inheritance have had a prominent role in structuring the hindgut communities, especially of the parabasalids, but dispersal and environmental acquisition have played a larger role in community composition than previously expected.
Asunto(s)
Bacterias/clasificación , Biota , Isópteros/microbiología , Parabasalidea/clasificación , Animales , Bacterias/genética , Bacteroidetes , Análisis por Conglomerados , Cucarachas , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Protozoario/química , ADN Protozoario/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Tracto Gastrointestinal/microbiología , Datos de Secuencia Molecular , Parabasalidea/genética , Filogenia , Análisis de Secuencia de ADN , TenericutesRESUMEN
Kofoidia loriculata is a parabasalid symbiont inhabiting the hindgut of the lower termite Paraneotermes simplicicornis. It was initially described as a lophomonad due to its apical tuft of multiple flagella that disintegrate during cell division, but its phylogenetic relationships have not been investigated using molecular evidence. From single cell isolations, we sequenced the small subunit rRNA gene and determined that K. loriculata falls within the Cristamonadea, but is unrelated to other lophomonads. This analysis further demonstrates the polyphyly of the lophomonads and the necessity to re-assess the morphological and cellular evolution of the Cristamonadea.
Asunto(s)
Parabasalidea/clasificación , Filogenia , Animales , Secuencia de Bases , Evolución Biológica , Genes de ARNr , Isópteros , Parabasalidea/genética , ARN Ribosómico/genéticaRESUMEN
Lateral gene transfer (LGT) has impacted the evolutionary history of eukaryotes, though to a lesser extent than in bacteria and archaea. Detecting LGT and distinguishing it from single gene tree artifacts is difficult, particularly when considering very ancient events (i.e., over hundreds of millions of years). Here, we use two independent lines of evidence--a taxon-rich phylogenetic approach and an assessment of the patterns of gene presence/absence--to evaluate the extent of LGT in the parasitic amoebozoan genus Entamoeba. Previous work has suggested that a number of genes in the genome of Entamoeba spp. were acquired by LGT. Our approach, using an automated phylogenomic pipeline to build taxon-rich gene trees, suggests that LGT is more extensive than previously thought. Our analyses reveal that genes have frequently entered the Entamoeba genome via nonvertical events, including at least 116 genes acquired directly from bacteria or archaea, plus an additional 22 genes in which Entamoeba plus one other eukaryote are nested among bacteria and/or archaea. These genes may make good candidates for novel therapeutics, as drugs targeting these genes are less likely to impact the human host. Although we recognize the challenges of inferring intradomain transfers given systematic errors in gene trees, we find 109 genes supporting LGT from a eukaryote to Entamoeba spp., and 178 genes unique to Entamoeba spp. and one other eukaryotic taxon (i.e., presence/absence data). Inspection of these intradomain LGTs provide evidence of a common sister relationship between genes of Entamoeba (Amoebozoa) and parabasalids (Excavata). We speculate that this indicates a past close relationship (e.g., symbiosis) between ancestors of these extant lineages.
Asunto(s)
Entamoeba/clasificación , Entamoeba/genética , Transferencia de Gen Horizontal , Parabasalidea/clasificación , Parabasalidea/genética , Filogenia , Archaea/genética , Bacterias/genética , Evolución Molecular , GenomaRESUMEN
The parabasalian symbionts of lower termite hindgut communities are well-known for their large size and structural complexity. The most complex forms evolved multiple times independently from smaller and simpler flagellates, but we know little of the diversity of these small flagellates or their phylogenetic relationships to more complex lineages. To understand the true diversity of Parabasalia and how their unique cellular complexity arose, more data from smaller and simpler flagellates are needed. Here, we describe two new genera of small-to-intermediate size and complexity, represented by the type species Cthulhu macrofasciculumque and Cthylla microfasciculumque from Prorhinotermes simplex and Reticulitermes virginicus, respectively (both hosts confirmed by DNA barcoding). Both genera have a single anterior nucleus embeded in a robust protruding axostyle, and an anterior bundle flagella (and likely a single posterior flagellum) that emerge slightly subanteriorly and have a distinctive beat pattern. Cthulhu is relatively large and has a distinctive bundle of over 20 flagella whereas Cthylla is smaller, has only 5 anterior flagella and closely resembles several other parababsalian genera. Molecular phylogenies based on small subunit ribosomal RNA (SSU rRNA) show both genera are related to previously unidentified environmental sequences from other termites (possibly from members of the Tricercomitidae), which all branch as sisters to the Hexamastigitae. Altogether, Cthulhu likely represents another independent origin of relatively high cellular complexity within parabasalia, and points to the need for molecular characterization of other key taxa, such as Tricercomitus.
Asunto(s)
Isópteros/parasitología , Parabasalidea/clasificación , Parabasalidea/genética , Animales , Secuencia de Bases , Código de Barras del ADN Taxonómico , ADN Protozoario/genética , Isópteros/genética , Datos de Secuencia Molecular , Parabasalidea/fisiología , Filogenia , ARN Ribosómico/genética , SimbiosisRESUMEN
An important and undervalued challenge in characterizing symbiotic protists is the accurate identification of their host species. Here, we use DNA barcoding to resolve one confusing case involving parabasalian symbionts in the hindgut of the Hawaiian lowland tree termite, Incisitermes immigrans, which is host to several parabasalians, including the type species for the genus Coronympha, C. clevelandii. We collected I. immigrans from its type locality (Hawaii), confirmed its identity by DNA barcoding, and characterized the phylogenetic position of two symbionts, C. clevelandii and Trichonympha subquasilla. These data show that previous molecular surveys of "I. immigrans" are, in fact, mainly derived from the Caribbean termite I. schwarzi, and perhaps also another related species. These results emphasize the need for host barcoding, clarify the relationship between morphologically distinct Coronympha species, and also suggest some interesting distribution patterns of nonendemic termite species and their symbionts.
Asunto(s)
Hypermastigia/fisiología , Isópteros/parasitología , Parabasalidea/fisiología , Animales , Hypermastigia/clasificación , Hypermastigia/genética , Parabasalidea/clasificación , Parabasalidea/genética , Filogenia , ARN Ribosómico/genética , SimbiosisRESUMEN
Staurojoenina is a large and structurally complex genus of hypermastigont parabasalians found in the hindgut of lower termites. Although several species of Staurojoenina have been described worldwide, all Staurojoenina observed to date in different species of North American termites have been treated as the same species, S. assimilis. Here, we characterize Staurojoenina from the North American termite Neotermes jouteli using light microscopy, scanning electron microscopy, and phylogenetic analysis of small subunit ribosomal RNA, and compare it with S. assimilis from its type host, Incisitermes minor. The basic morphological characteristics of the N. jouteli symbiont, including its abundant bacterial epibionts, are similar as far as they may be compared with existing data from S. assimilis, although not consistently identical. In contrast, we find that they are extremely distantly related at the molecular level, sharing a pairwise similarity of SSU rRNA genes comparable to that seen between different genera or even families of other parabasalians. Based on their evolutionary distance and habitat in different termite genera, we consider the N. jouteli Staurojoenina to be distinct from S. assimilis, and describe a new species, Staurojoenina mulleri, in honor of the pioneering parabasalian researcher, Miklos Muller.