Q37379527
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The notion that mitochondria cannot be lost was shattered with the report of an oxymonad Monocercomonoides exilis, the first eukaryote arguably without any mitochondrion. Yet, questions remain about whether this extends beyond the single species and how this transition took place. The Oxymonadida is a group of gut endobionts taxonomically housed in the Preaxostyla which also contains free-living flagellates of the genera Trimastix and Paratrimastix. The latter two taxa harbour conspicuous mitochondrion-related organelles (MROs). Here we report high-quality genome and transcriptome assemblies of two Preaxostyla representatives, the free-living Paratrimastix pyriformis and the oxymonad Blattamonas nauphoetae. We performed thorough comparisons among all available genomic and transcriptomic data of Preaxostyla to further decipher the evolutionary changes towards amitochondriality, endobiosis, and unstacked Golgi. Our results provide insights into the metabolic and endomembrane evolution, but most strikingly the data confirm the complete loss of mitochondria for all three oxymonad species investigated (M. exilis, B. nauphoetae, and Streblomastix strix), suggesting the amitochondriate status is common to a large part if not the whole group of Oxymonadida. This observation moves this unique loss to 100 MYA when oxymonad lineage diversified.
- MeSH
- Eukaryota * genetika MeSH
- fylogeneze MeSH
- genomika MeSH
- mitochondrie genetika MeSH
- Oxymonadida * genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Aerobic organisms require oxygen for respiration but must simultaneously cope with oxidative damages inherently linked with this molecule. Unicellular amoeboflagellates of the genus Naegleria, containing both free-living species and opportunistic parasites, thrive in aerobic environments. However, they are also known to maintain typical features of anaerobic organisms. Here, we describe the mechanisms of oxidative damage mitigation in Naegleria gruberi and focus on the molecular characteristics of three noncanonical proteins interacting with oxygen and its derived reactive forms. We show that this protist expresses hemerythrin, protoglobin, and an aerobic-type rubrerythrin, with spectral properties characteristic of the cofactors they bind. We provide evidence that protoglobin and hemerythrin interact with oxygen in vitro and confirm the mitochondrial localization of rubrerythrin by immunolabeling. Our proteomic analysis and immunoblotting following heavy metal treatment revealed upregulation of hemerythrin, while rotenone treatment resulted in an increase in rubrerythrin protein levels together with a vast upregulation of alternative oxidase. Our study provided new insights into the mechanisms employed by N. gruberi to cope with different types of oxidative stress and allowed us to propose specific roles for three unique and understudied proteins: hemerythrin, protoglobin, and rubrerythrin.
BACKGROUND: Mitochondria and peroxisomes are the two organelles that are most affected during adaptation to microoxic or anoxic environments. Mitochondria are known to transform into anaerobic mitochondria, hydrogenosomes, mitosomes, and various transition stages in between, collectively called mitochondrion-related organelles (MROs), which vary in enzymatic capacity. Anaerobic peroxisomes were identified only recently, and their putatively most conserved function seems to be the metabolism of inositol. The group Archamoebae includes anaerobes bearing both anaerobic peroxisomes and MROs, specifically hydrogenosomes in free-living Mastigamoeba balamuthi and mitosomes in the human pathogen Entamoeba histolytica, while the organelles within the third lineage represented by Pelomyxa remain uncharacterized. RESULTS: We generated high-quality genome and transcriptome drafts from Pelomyxa schiedti using single-cell omics. These data provided clear evidence for anaerobic derivates of mitochondria and peroxisomes in this species, and corresponding vesicles were tentatively identified in electron micrographs. In silico reconstructed MRO metabolism harbors respiratory complex II, electron-transferring flavoprotein, a partial TCA cycle running presumably in the reductive direction, pyruvate:ferredoxin oxidoreductase, [FeFe]-hydrogenases, a glycine cleavage system, a sulfate activation pathway, and an expanded set of NIF enzymes for iron-sulfur cluster assembly. When expressed in the heterologous system of yeast, some of these candidates localized into mitochondria, supporting their involvement in the MRO metabolism. The putative functions of P. schiedti peroxisomes could be pyridoxal 5'-phosphate biosynthesis, amino acid and carbohydrate metabolism, and hydrolase activities. Unexpectedly, out of 67 predicted peroxisomal enzymes, only four were also reported in M. balamuthi, namely peroxisomal processing peptidase, nudix hydrolase, inositol 2-dehydrogenase, and D-lactate dehydrogenase. Localizations in yeast corroborated peroxisomal functions of the latter two. CONCLUSIONS: This study revealed the presence and partially annotated the function of anaerobic derivates of mitochondria and peroxisomes in P. schiedti using single-cell genomics, localizations in yeast heterologous systems, and transmission electron microscopy. The MRO metabolism resembles that of M. balamuthi and most likely reflects the state in the common ancestor of Archamoebae. The peroxisomal metabolism is strikingly richer in P. schiedti. The presence of myo-inositol 2-dehydrogenase in the predicted peroxisomal proteome corroborates the situation in other Archamoebae, but future experimental evidence is needed to verify additional functions of this organelle.
- MeSH
- Amoeba * genetika metabolismus MeSH
- anaerobióza MeSH
- Archamoebae * genetika metabolismus MeSH
- genomika MeSH
- lidé MeSH
- mitochondrie metabolismus MeSH
- peroxizomy metabolismus MeSH
- Saccharomyces cerevisiae MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Among human and veterinary parasitic diseases the trematodiases (e.g. schistosomiasis, fascioliasis) represent a problem of global importance with vast social, economic and public health impacts, especially in developing countries. Therefore, host-parasite (host-trematode) interactions represent a key topic in many research laboratories, and modern approaches and technologies allow us to study the molecular basis of these interactions. As a consequence, key molecules produced by trematodes in order to ensure parasite invasion and survival within a hosts can be characterized. Trematode peptidases certainly belong to such molecules; as they are indispensable biocatalysts in a number of basal biological processes in trematodes (e.g. tissue invasion/migration, nutrition, immune evasion or other host-parasite interactions). Schistosoma mansoni cercarial elastase (CE) (penetration enzyme), cathepsin B (CB) (mainly nutrition enzyme) and Fasciola hepatica cathepsin L (CL) (nutrition, immune evasion enzyme) are probably the most studied trematode peptidases with well-characterized critical functions. Due to the importance of peptidases in host-parasite interactions they are considered to be promising targets for the development of novel chemotherapeutic drugs and vaccines against a number of trematodiases, including schistosomiasis, fascioliasis, paragonimiasis and opisthorchiasis. The present chapter summarizes the data on the biochemical and molecular features of the major trematode peptidases, and describes their role in trematode biology and host-parasite interactions based on proteolysis (peptidolysis).
- MeSH
- faktory virulence genetika metabolismus MeSH
- infekce červy třídy Trematoda parazitologie veterinární MeSH
- interakce hostitele a parazita MeSH
- lidé MeSH
- proteasy genetika metabolismus MeSH
- Trematoda enzymologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
The family Monocercomonadidae (Parabasala, Trichomonadida) is characterized by the absence of a costa and in most species also of an undulating membrane; both of which are typical structures of trichomonadids. We have examined 25 isolates of Monocercomonadidae species by sequencing of the SSU rDNA and the ITS region and by light and transmission electron microscopy. The isolates formed three distinct phylogenetically unrelated clades: (1) Monocercomonas colubrorum, (2) Monocercomonas ruminantium together with a strain ATCC 50321 designated as Pseudotrichomonas keilini, and (3) Hexamastix. Twenty isolates of Monocercomonas colubrorum split into three clades with no host-specificity. The morphological differences among clades were insufficient to classify them as a separate species. Non-monophyly of the cattle commensal Monocercomonas ruminantium with the type species Monocercomonas colubrorum and absence of Pseudotrichomonas characters in the free-living strain ATCC 50321 led to their reclassification into a new genus (Honigbergiella gen. nov.). The close relationship of these strains indicates a recent switch between a free-living habit and endobiosis. Two strains of Hexamastix represented different species -Hexamastix kirbyi Honigberg 1955 and Hexamastix mitis sp. nov. Polyphyly of the Monocercomonadidae confirmed that the absence of a costa and an undulating membrane are not taxonomically significant characters and were probably secondarily lost in some or all clades. Our observations, however, indicated that other characters - infrakinetosomal body, comb-like structure, marginal lamella, and the type of axostyle - are fully consistent with the position of Monocercomonadidae species in the parabasalian tree and are, therefore, reasonable taxonomic characters.
- MeSH
- financování organizované MeSH
- fylogeneze MeSH
- geny rRNA MeSH
- mezerníky ribozomální DNA genetika MeSH
- molekulární sekvence - údaje MeSH
- organely ultrastruktura MeSH
- protozoální DNA genetika chemie MeSH
- ribozomální DNA genetika chemie MeSH
- RNA protozoální genetika MeSH
- RNA ribozomální 18S genetika MeSH
- sekvenční analýza DNA MeSH
- sekvenční homologie nukleových kyselin MeSH
- transmisní elektronová mikroskopie MeSH
- Trichomonadida cytologie genetika klasifikace ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
We studied morphological and molecular polymorphism of 53 Tetratrichomonas isolates obtained from amphibian, reptilian, mammalian hosts, and from a slug with the aid of protargol staining and analyses of ITS1-5.8S rRNA-ITS2, SSU rRNA, and alpha-tubulin gene sequences. The phylogenetic tree based on the concatenate of all sequences showed the monophyly of the genus Tetratrichomonas with respect to the genus Trichomonas. Our data suggest that two parabasalid genera, Pentatrichomonoides and Trichomonoides, may belong to the genus Tetratrichomonas. Tetratrichomonas isolates were divided into 16 robust host-specific and monophyletic groups that probably represent separate, mostly new, species. As only five Tetratrichomonas species were described from the examined host taxa so far, our study uncovered considerable species diversity within the genus. The wide host range, high level of species-specific host specificity, and newly revealed biodiversity make the genus Tetratrichomonas a valuable model for studying evolution of parasites.
- MeSH
- Bayesova věta MeSH
- financování organizované MeSH
- fylogeneze MeSH
- genetická variace imunologie MeSH
- interakce hostitele a parazita genetika MeSH
- mezerníky ribozomální DNA genetika MeSH
- molekulární evoluce MeSH
- molekulární sekvence - údaje MeSH
- myši parazitologie MeSH
- prasata parazitologie MeSH
- protozoální DNA genetika chemie MeSH
- RNA ribozomální 5.8S genetika MeSH
- sekvenční analýza DNA MeSH
- Trichomonadida genetika klasifikace MeSH
- zvířata MeSH
- Check Tag
- myši parazitologie MeSH
- zvířata MeSH
In Iceland, the examination of whooper swans (Cygnus cygnus L.) viscera resulted in the detection of adult digenean flukes of the family Schistosomatidae. The mature worms occurring in the blood vessels of the large intestine and mesenterium caused vascular lesions, around the eggs deposited in the intestinal mucosa and liver granulomatous reactions developed. The morphology of the isolated schistosomes shows certain similarity with the flukes of the genus Trichobilharzia; in males reduced gynecophoral canal, and on both sexes both suckers and spatulate ends are present. However, the Icelandic flukes possess other morphological features which are distinct from the genus: the point of caecal reunion in males takes place posterior to gynecophoral canal and the genital pore is behind acetabulum and anterior to caecal reunion. In order to evaluate the identity of Icelandic schistosomes, sequencing of ITS region of DNA was performed, and the obtained sequence was deposited in GenBank under the accession no. DQ067561. Following phylogenetic analysis of relationship between the sequence of Icelandic flukes and database sequences of other bird schistosome genera (Trichobilharzia, Gigantobilharzia and Dendritobilharzia) showed different position of Icelandic worms in the phylogenetic tree. In conclusion, our study revealed new genus and species of schistosome flukes--Allobilharzia visceralis gen. et sp. n.
- MeSH
- Anseriformes anatomie a histologie parazitologie MeSH
- feces parazitologie MeSH
- financování organizované MeSH
- fylogeneze MeSH
- molekulární sekvence - údaje MeSH
- nemoci ptáků parazitologie MeSH
- počet parazitárních vajíček MeSH
- polymerázová řetězová reakce MeSH
- ribozomální DNA genetika MeSH
- Schistosoma anatomie a histologie genetika klasifikace MeSH
- schistosomóza parazitologie veterinární MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
The protozoan genus Cochlosoma includes parasitic intestinal flagellates of birds and mammals of uncertain taxonomic classification. The presence of an adhesive disc, superficially similar to that of Giardia, led to a proposal that Cochlosoma should be classified as diplomonads. Careful morphological and ultrastructural observations, however, revealed conspicuous homologies to trichomonads. We addressed the question of classification and phylogenetic affiliation of Cochlosoma using the methods of molecular phylogenetics. Analyses based on the 16S rRNA gene sequence of the species Cochlosoma anatis very robustly placed Cochlosoma in the clade of the parabasalid subfamilies Trichomonadinae, Trichomitopsiinae and Pentatrichomonoidinae of the order Trichomonadida (bootstraps >94 %). The data did not provide robust support for any particular position of Cochlosoma within this clade because the sequence suffered from mutational saturation and produced a long branch. The most probable sister taxon of Cochlosoma is the genus Pentatrichomonas, because their relationship was supported specifically by the slowest-mutating, least-saturated positions as determined using the method slow-fast. Classification of the order Trichomonadida was revised to accommodate knowledge about its phylogeny - the family Cochlosomatidae and subfamilies Trichomitopsiinae and Pentatrichomonoidinae were abandoned, Trichomonadidae was amended and new families Tritrichomonadidae (formerly a subfamily) and Trichomitidae were proposed.
