The shape and form of the flagellated eukaryotic parasite Leishmania is sculpted to its ecological niches and needs to be transmitted to each generation with great fidelity. The shape of the Leishmania cell is defined by the sub-pellicular microtubule array and the positioning of the nucleus, kinetoplast and the flagellum within this array. The flagellum emerges from the anterior end of the cell body through an invagination of the cell body membrane called the flagellar pocket. Within the flagellar pocket the flagellum is laterally attached to the side of the flagellar pocket by a cytoskeletal structure called the flagellum attachment zone (FAZ). During the cell cycle single copy organelles duplicate with a new flagellum assembling alongside the old flagellum. These are then segregated between the two daughter cells by cytokinesis, which initiates at the anterior cell tip. Here, we have investigated the role of the FAZ in the morphogenesis of the anterior cell tip. We have deleted the FAZ filament protein, FAZ2 and investigated its function using light and electron microscopy and infection studies. The loss of FAZ2 caused a disruption to the membrane organisation at the anterior cell tip, resulting in cells that were connected to each other by a membranous bridge structure between their flagella. Moreover, the FAZ2 null mutant was unable to develop and proliferate in sand flies and had a reduced parasite burden in mice. Our study provides a deeper understanding of membrane-cytoskeletal interactions that define the shape and form of an individual cell and the remodelling of that form during cell division.
- MeSH
- buněčná membrána MeSH
- cytokineze MeSH
- cytoskelet metabolismus MeSH
- flagella fyziologie ultrastruktura MeSH
- interakce hostitele a parazita * MeSH
- Leishmania růst a vývoj ultrastruktura MeSH
- leishmanióza parazitologie MeSH
- morfogeneze * MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- protozoální proteiny genetika metabolismus MeSH
- Psychodidae parazitologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- protozoální proteiny MeSH
Introduced about a century ago, suramin remains a frontline drug for the management of early-stage East African trypanosomiasis (sleeping sickness). Cellular entry into the causative agent, the protozoan parasite Trypanosoma brucei, occurs through receptor-mediated endocytosis involving the parasite's invariant surface glycoprotein 75 (ISG75), followed by transport into the cytosol via a lysosomal transporter. The molecular basis of the trypanocidal activity of suramin remains unclear, but some evidence suggests broad, but specific, impacts on trypanosome metabolism (i.e. polypharmacology). Here we observed that suramin is rapidly accumulated in trypanosome cells proportionally to ISG75 abundance. Although we found little evidence that suramin disrupts glycolytic or glycosomal pathways, we noted increased mitochondrial ATP production, but a net decrease in cellular ATP levels. Metabolomics highlighted additional impacts on mitochondrial metabolism, including partial Krebs' cycle activation and significant accumulation of pyruvate, corroborated by increased expression of mitochondrial enzymes and transporters. Significantly, the vast majority of suramin-induced proteins were normally more abundant in the insect forms compared with the blood stage of the parasite, including several proteins associated with differentiation. We conclude that suramin has multiple and complex effects on trypanosomes, but unexpectedly partially activates mitochondrial ATP-generating activity. We propose that despite apparent compensatory mechanisms in drug-challenged cells, the suramin-induced collapse of cellular ATP ultimately leads to trypanosome cell death.
- Klíčová slova
- Trypanosoma brucei, differentiation, drug action, drug mechanisms, energy homeostasis, glycosomes, metabolomics, parasite metabolism, polypharmacology, proteomics, sleeping sickness, suramin, trypanosome,
- MeSH
- adenosintrifosfát metabolismus MeSH
- energetický metabolismus účinky léků MeSH
- flagella účinky léků metabolismus ultrastruktura MeSH
- glykolýza účinky léků MeSH
- kyselina pyrohroznová metabolismus MeSH
- membránový potenciál mitochondrií účinky léků MeSH
- metabolom účinky léků MeSH
- mikrotělíska účinky léků metabolismus ultrastruktura MeSH
- mitochondrie účinky léků metabolismus ultrastruktura MeSH
- molekulární modely MeSH
- prolin metabolismus MeSH
- proteom metabolismus MeSH
- protonové ATPasy metabolismus MeSH
- protozoální proteiny metabolismus MeSH
- suramin farmakologie MeSH
- Trypanosoma brucei brucei metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- adenosintrifosfát MeSH
- kyselina pyrohroznová MeSH
- prolin MeSH
- proteom MeSH
- protonové ATPasy MeSH
- protozoální proteiny MeSH
- suramin MeSH
Leishmania kinetoplastid parasites infect millions of people worldwide and have a distinct cellular architecture depending on location in the host or vector and specific pathogenicity functions. An invagination of the cell body membrane at the base of the flagellum, the flagellar pocket (FP), is an iconic kinetoplastid feature, and is central to processes that are critical for Leishmania pathogenicity. The Leishmania FP has a bulbous region posterior to the FP collar and a distal neck region where the FP membrane surrounds the flagellum more closely. The flagellum is attached to one side of the FP neck by the short flagellum attachment zone (FAZ). We addressed whether targeting the FAZ affects FP shape and its function as a platform for host-parasite interactions. Deletion of the FAZ protein, FAZ5, clearly altered FP architecture and had a modest effect in endocytosis but did not compromise cell proliferation in culture. However, FAZ5 deletion had a dramatic impact in vivo: Mutants were unable to develop late-stage infections in sand flies, and parasite burdens in mice were reduced by >97%. Our work demonstrates the importance of the FAZ for FP function and architecture. Moreover, we show that deletion of a single FAZ protein can have a large impact on parasite development and pathogenicity.
- Klíčová slova
- Leishmania, flagellar pocket, morphogenesis, pathogenicity,
- MeSH
- buněčná membrána metabolismus MeSH
- cilie genetika fyziologie ultrastruktura MeSH
- delece genu MeSH
- endocytóza MeSH
- flagella genetika fyziologie ultrastruktura MeSH
- interakce hostitele a parazita MeSH
- Leishmania genetika patogenita fyziologie ultrastruktura MeSH
- mezibuněčné spoje MeSH
- myši MeSH
- protozoální proteiny genetika metabolismus MeSH
- Psychodidae parazitologie MeSH
- virulence genetika MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- protozoální proteiny MeSH
Spermatozoon formation in Caryophyllaeides fennica (Schneider, 1902) is characterised by the following: (1) apical electron-dense material in the zone of differentiation, (2) typical striated roots situated unconventionally in opposite directions in early stages of spermiogenesis, (3) intercentriolar body composed of three electron-dense and two electron-lucent plates, (4) free flagellum and a flagellar bud that correspond to a greatly reduced flagellum and (5) rotation of free flagellum and a flagellar bud to the median cytoplasmic process at 90°. The development of two flagella of significantly unequal length clearly supports a derived form of spermiogenesis in the Caryophyllidea. New for cestodes is a finding of two additional striated roots situated opposite each other, in conjunction with both the flagellar bud and free flagellum. Mutual position of additional striated roots and typical striated roots is parallel in early stages and perpendicular in advanced stages of spermiogenesis. A complete proximodistal fusion gives rise to a mature spermatozoon consisting of one axoneme, parallel cortical microtubules, a nucleus and a moderately electron-dense cytoplasm with glycogen particles, detected by a technique of Thiéry (J Microsc 6:987-1018, 1967), in the principal regions (II, III, IV). Electron tomography analysis of the free flagellum and one axoneme of a mature spermatozoon of C. fennica provides clear evidence, for the first time, that two tubular structures are present in the central axonemal electron-dense core. Phylogenetically important aspects of spermiogenesis of the Caryophyllidea with one axoneme, and other cestodes with one or two axonemes, are briefly reviewed and discussed.
- Klíčová slova
- Caryophyllaeides fennica, Caryophyllidea, Spermatozoon, Spermiogenesis, Ultrastructure,
- MeSH
- axonema ultrastruktura MeSH
- buněčné jádro ultrastruktura MeSH
- Cestoda ultrastruktura MeSH
- cestodózy MeSH
- flagella ultrastruktura MeSH
- mikrotubuly ultrastruktura MeSH
- spermatogeneze fyziologie MeSH
- spermie ultrastruktura MeSH
- tomografie elektronová MeSH
- transmisní elektronová mikroskopie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
We report discovery of a new lineage of anaerobic marine amoebae and amoeboflagellates, Anaeramoeba gen. nov., represented by six newly described species. The trophic form of Anaeramoeba spp. is an amoeba corresponding to the uncommon flabellate or flamellian morphotype - it is fan-shaped and produces an anterior, flattened hyaline zone and posterior hyaline projections. In contrast to other representatives of these morphotypes, cells of Anaeramoeba spp. possess acristate mitochondrion-related organelles associated with prokaryotic symbionts, and a large acentriolar centrosome. Surprisingly, two Anaeramoeba species form morphologically unique flagellates with two or four isokont, thickened flagella. Phylogenetic analyses of the SSU rRNA gene showed that Anaeramoeba spp. form a clade, which is not robustly related to any other eukaryotic lineage. We accommodate Anaeramoeba in a new family Anaeramoebidae, which we classify as Eukaryota incertae sedis.
- Klíčová slova
- Amoeba, Eukaryota incertae sedis, amoeboflagellate, anaerobiosis, new species.,
- MeSH
- druhová specificita MeSH
- Eukaryota klasifikace genetika ultrastruktura MeSH
- flagella ultrastruktura MeSH
- fylogeneze * MeSH
- RNA protozoální genetika MeSH
- RNA ribozomální genetika MeSH
- transmisní elektronová mikroskopie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- RNA protozoální MeSH
- RNA ribozomální MeSH
The transition zone (TZ) of eukaryotic cilia and flagella is a structural intermediate between the basal body and the axoneme that regulates ciliary traffic. Mutations in genes encoding TZ proteins (TZPs) cause human inherited diseases (ciliopathies). Here, we use the trypanosome to identify TZ components and localize them to TZ subdomains, showing that the Bardet-Biedl syndrome complex (BBSome) is more distal in the TZ than the Meckel syndrome (MKS) complex. Several of the TZPs identified here have human orthologs. Functional analysis shows essential roles for TZPs in motility, in building the axoneme central pair apparatus and in flagellum biogenesis. Analysis using RNAi and HaloTag fusion protein approaches reveals that most TZPs (including the MKS ciliopathy complex) show long-term stable association with the TZ, whereas the BBSome is dynamic. We propose that some Bardet-Biedl syndrome and MKS pleiotropy may be caused by mutations that impact TZP complex dynamics.
- Klíčová slova
- BBSome, MKS/B9 complex, cilium/flagellum, transition zone, trypanosome,
- MeSH
- Bardetův-Biedlův syndrom genetika metabolismus MeSH
- bazální tělíska metabolismus ultrastruktura MeSH
- cilie genetika metabolismus MeSH
- ciliopatie genetika metabolismus MeSH
- cytoskelet metabolismus ultrastruktura MeSH
- encefalokéla genetika metabolismus MeSH
- flagella genetika metabolismus ultrastruktura MeSH
- fluorescenční mikroskopie MeSH
- kompartmentace buňky MeSH
- lidé MeSH
- mutace MeSH
- polycystická choroba ledvin genetika metabolismus MeSH
- poruchy ciliární motility genetika metabolismus MeSH
- proteom genetika metabolismus MeSH
- protozoální proteiny genetika metabolismus MeSH
- retinopathia pigmentosa MeSH
- RNA interference MeSH
- transmisní elektronová mikroskopie MeSH
- Trypanosoma genetika metabolismus ultrastruktura MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- proteom MeSH
- protozoální proteiny MeSH
This study was conducted to investigate Brachymystax lenok tsinlingensis spermatozoa cell morphology and ultrastructure through scanning and transmission electron microscopy. Findings revealed that the spermatozoa can be differentiated into three major parts: a spherical head without an acrosome, a short mid-piece, and a long, cylindrical flagellum. The mean length of the spermatozoa was 36.11±2.84μm, with a spherical head length of 2.78±0.31μm. The mean anterior and posterior head widths were 2.20±0.42μm and 2.55±0.53μm, respectively. The nuclear fossa was positioned at the base of the nucleus that contained the anterior portion of flagellum and a centriolar complex (proximal and distal centrioles). The short mid-piece was located laterally to the nucleus and possessed just one spherical mitochondrion with a mean diameter of 0.65±0.14μm. The spermatozoa flagellum was long and cylindrical, and could be separated into two parts: a long main-piece and a short end-piece. The main piece of the flagellum had short irregular side-fins. The axoneme composed the typical '9+2' microtubular doublet structure and was enclosed by the cell membran e. This study confirmed that B. lenok tsinlingensis spermatozoa can be categorized as teleostean "Type I" spermatozoa; 'primitive' or 'ect-aquasperm type' spermatozoa. To the best of the authers knowledge, this was the first study conducted on the morphology and ultrastructure of B. lenok tsinlingensis spermatozoa.
- Klíčová slova
- Brachymystax lenok tsinlingensis, Morphology, Scanning electron microscopy, Spermatozoa, Transmission electron microscopy, Ultrastructure,
- MeSH
- akrozom ultrastruktura MeSH
- axonema ultrastruktura MeSH
- buněčné jádro ultrastruktura MeSH
- centrioly ultrastruktura MeSH
- flagella ultrastruktura MeSH
- mikroskopie elektronová rastrovací MeSH
- mitochondrie ultrastruktura MeSH
- Salmonidae anatomie a histologie růst a vývoj MeSH
- spermie ultrastruktura MeSH
- transmisní elektronová mikroskopie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The microtubular cytoskeleton of most single-celled eukaryotes radiates from an organizing center called the flagellar apparatus, which is essential for locomotion, feeding and reproduction. The structure of the flagellar apparatus tends to be conserved within diverse clades of eukaryotes, and modifications of this overall structure distinguish different clades from each other. Understanding the unity and diversity of the flagellar apparatus provides important insights into the evolutionary history of the eukaryotic cell. Diversification of the flagellar apparatus is particularly apparent during the multiple independent transitions to parasitic lifestyles from free-living ancestors. However, our understanding of these evolutionary transitions is hampered by the lack of detailed comparisons of the microtubular root systems in different lineages of parasitic microbial eukaryotes and those of their closest free-living relatives. Here we help to establish this comparative context by examining the unity and diversity of the flagellar apparatus in six major clades containing both free-living lineages and endobiotic (parasitic and symbiotic) microbial eukaryotes: stramenopiles (e.g., Phytophthora), fornicates (e.g., Giardia), parabasalids (e.g., Trichomonas), preaxostylids (e.g., Monocercomonoides), kinetoplastids (e.g., Trypanosoma), and apicomplexans (e.g., Plasmodium). These comparisons enabled us to address some broader patterns associated with the evolution of parasitism, including a general trend toward a more streamlined flagellar apparatus.
- Klíčová slova
- Biodiversity, Cytoskeleton, Evolution, Free-living, MTOC, Microtubules,
- MeSH
- biologická evoluce * MeSH
- cytoskelet metabolismus MeSH
- flagella metabolismus ultrastruktura MeSH
- lokomoce MeSH
- mikrotubuly metabolismus MeSH
- molekulární evoluce MeSH
- paraziti klasifikace fyziologie MeSH
- rozmnožování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Trimastigids are free-living, anaerobic protists that are closely related to the symbiotic oxymonads, forming together the taxon Preaxostyla (Excavata: Metamonada). We isolated fourteen new strains morphologically corresponding to two species assigned to Trimastix (until now the only genus of trimastigids), Trimastix marina and Trimastix pyriformis. Unexpectedly, marine strains of Trimastix marina branch separately from freshwater strains of this morphospecies in SSU rRNA gene trees, and instead form the sister group of all other Preaxostyla. This position is confirmed by three-gene phylogenies. Ultrastructural examination of a marine isolate of Trimastix marina demonstrates a combination of trimastigid-like features (e.g. preaxostyle-like I fibre) and ancestral characters (e.g. absence of thickened flagellar vane margins), consistent with inclusion of marine T. marina within Preaxostyla, but also supporting its distinctiveness from 'freshwater T. marina' and its deep-branching position within Preaxostyla. Since these results indicate paraphyly of Trimastix as currently understood, we transfer the other better-studied trimastigids to Paratrimastix n. gen. and Paratrimastigidae n. fam. The freshwater form previously identified as T. marina is described as Paratrimastix eleionoma n. sp., and Trimastix pyriformis becomes Paratrimastix pyriformis n. comb. Because of its phylogenetic position, 'true' Trimastix is potentially important for understanding the evolution of mitochondrion-related organelles in metamonads.
- Klíčová slova
- Anaerobe, cytoskeleton, flagellar apparatus, oxymonads, phylogeny, ultrastructure.,
- MeSH
- druhová specificita MeSH
- Eukaryota klasifikace genetika izolace a purifikace ultrastruktura MeSH
- flagella ultrastruktura MeSH
- fylogeneze * MeSH
- organely ultrastruktura MeSH
- RNA ribozomální 18S genetika MeSH
- vodní organismy klasifikace genetika izolace a purifikace ultrastruktura MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- RNA ribozomální 18S MeSH
Although environmental DNA surveys improve our understanding of biodiversity, interpretation of unidentified lineages is limited by the absence of associated morphological traits and living cultures. Unidentified lineages of marine stramenopiles are called "MAST clades". Twenty-five MAST clades have been recognized: MAST-1 through MAST-25; seven of these have been subsequently discarded because the sequences representing those clades were found to either (1) be chimeric or (2) affiliate within previously described taxonomic groups. Eighteen MAST clades remain without a cellular identity. Moreover, the discarded "MAST-13" has been used in different studies to refer to two different environmental sequence clades. After establishing four cultures representing two different species of heterotrophic stramenopiles and then characterizing their morphology and molecular phylogenetic positions, we determined that the two different species represented the two different MAST-13 clades: (1) a lorica-bearing Bicosoeca kenaiensis and (2) a microaerophilic flagellate previously named "Cafeteria marsupialis". Both species were previously described with only light microscopy; no cultures, ultrastructural data or DNA sequences were available from these species prior to this study. The molecular phylogenetic position of three different "C. marsupialis" isolates was not closely related to the type species of Cafeteria; therefore, we established a new genus for these isolates, Cantina gen. nov.
- Klíčová slova
- Bicosoecid, MAST, biodiversity, culture-independent molecular methods, environmental DNA sequence surveys, molecular phylogeny, protist, ultrastructure,
- MeSH
- flagella ultrastruktura MeSH
- fylogeneze MeSH
- Heterokontophyta klasifikace cytologie genetika izolace a purifikace MeSH
- heterotrofní procesy MeSH
- molekulární sekvence - údaje MeSH
- mořská voda MeSH
- ribozomální DNA genetika MeSH
- RNA ribozomální 18S genetika MeSH
- sekvenční analýza DNA MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- ribozomální DNA MeSH
- RNA ribozomální 18S MeSH