Vladimír Hampl

Vladimír Hampl
Charles University in Prague | CUNI · Department of Parasitology (PF)

Doctor of Philosophy
Looking for new protist geeks into our team. Please write me an e-mail.

About

147
Publications
36,176
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
5,758
Citations
Introduction
I am interested in the event of loss of mitochondria in the protist group Preaxostyla. My group also examines biotic interactions between these protists and their prokaryotic companions in the culture and natively in the termite hindgut. Furthermore, we test the possibilities of directed evolution via mitochondrial knock-outs in other selected anaerobes and develop tools to study the evolution of protein import. We also love euglenids and their plastids :)

Publications

Publications (147)
Article
Monocercomonoides is a genus of anaerobic flagellates found mainly in the gut of insects and vertebrates. We explored the ploidy of six strains of Monocercomonoides using fluorescence in situ hybridization (FISH) with probes against the SufDSU gene known to be in a single copy in M. exilis. Our results show that all investigated strains are haploid...
Preprint
It has been long hypothesised that mitochondrial reduction is intrinsically related to the remodelling of Fe-S clusters assembly. Yet as our knowledge of divergent free-living protists broadens, so does the spectrum of variability within the range of mitochondrial-related organelles (MROs) fundamental functions. We resolved to high precision the MR...
Article
Full-text available
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...
Article
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 parasite, thrive in aerobic environments. However, they are also known to maintain typical features of...
Preprint
teaserEuglenoids show great promise to benefit our world; as biofuels, environmental remediators, anti-cancer agents, robotics design simulators and food nutritional agents, but the absence of reference genomes currently limit realizing these benefits. The Euglena International Network (EIN) (https://euglenanetwork.org/) aims to address these chall...
Article
Monocercomonoides exilis is considered the first known eukaryote to completely lack mitochondria. This conclusion is based primarily on a genomic and transcriptomic study which failed to identify any mitochondrial hallmark proteins. However, the available genome assembly has limited contiguity and around 1.5 % of the genome sequence is represented...
Article
Full-text available
Euglenids represent a group of protists with diverse modes of feeding. To date, only a partial genomic sequence of Euglena gracilis and transcriptomes of several phototrophic and secondarily osmotrophic species are available, while primarily heterotrophic euglenids are seriously undersampled. In this work, we begin to fill this gap by presenting ge...
Preprint
Full-text available
Pelomyxa schiedti is a free-living amoeba belonging to the group Archamoebae, which encompasses anaerobes bearing mitochondrion-related organelles (MROs) – hydrogenosomes in free-living Mastigamoeba balamuthi and mitosomes in the human pathogen Entamoeba histolytica . Anaerobic peroxisomes, another adaptation to anaerobic lifestyle, were identified...
Article
Full-text available
Although the mitochondria of extant eukaryotes share a single origin, functionally these organelles diversified to a great extent, reflecting lifestyles of the organisms that host them. In anaerobic protists of the group Metamonada, mitochondria are present in reduced forms (also termed hydrogenosomes or mitosomes) and a complete loss of mitochondr...
Preprint
Full-text available
Euglenids represent a group of protists with diverse modes of feeding. To date, only a partial genomic sequence of Euglena gracilis and transcriptomes of several phototrophic and secondarily osmotrophic species are available, while primarily heterotrophic euglenids are seriously undersampled. In this work, we begin to fill this gap by presenting ge...
Article
Euglena gracilis is a photosynthetic flagellate possessing chlorophyte-derived secondary plastids that are enclosed by only three enveloping membranes, unlike most secondary plastids, which are surrounded by four membranes. It has generally been assumed that the two innermost E. gracilis plastid envelopes originated from the primary plastid, while...
Article
Full-text available
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
Full-text available
The order Trypanosomatida has been well studied due to its pathogenicity and the unique biology of the mitochondrion. In Trypanosoma brucei, four DNA polymerases, namely PolIA, PolIB, PolIC, and PolID, related to bacterial DNA polymerase I (PolI), were shown to be localized in mitochondria experimentally. These mitochondrion-localized DNA polymeras...
Article
Full-text available
Background: The Euglenozoa are a protist group with an especially rich history of evolutionary diversity. They include diplonemids, representing arguably the most species-rich clade of marine planktonic eukaryotes; trypanosomatids, which are notorious parasites of medical and veterinary importance; and free-living euglenids. These different lifest...
Article
Euglenophyceae are unicellular algae with the majority of their diversity known from small freshwater reservoirs. Only two dozen species have been described to occur in marine habitats, but their abundance and diversity remain unexplored. Phylogenetic studies revealed marine prasinophyte green alga, Pyramimonas parkeae, as the closest extant relati...
Article
Full-text available
Euglena spp. are phototrophic flagellates with considerable ecological presence and impact. E. gracilis harbours secondary green plastids, but an incompletely characterized proteome precludes accurate understanding of both plastid function and evolutionary history. Using subcellular fractionation, an improved sequence database and mass spectrometry...
Article
Lower termites harbor in their hindgut complex microbial communities that are involved in the digestion of cellulose. Among these are protists, which are usually associated with specific bacterial symbionts found on their surface or inside their cells. While these form the foundations of a classic system in symbiosis research, we still know little...
Chapter
Full-text available
Decades of investigations have clearly shown that protists living in low-oxygen environments possess mitochondria despite their textbook function, oxidative phosphorylation, is usually absent. The presence of these, in some cases, very rudimental mitochondria has been ascribed to their irreplaceable role in the synthesis of FeS clusters, prosthetic...
Article
Full-text available
The discovery that the protist Monocercomonoides exilis completely lacks mitochondria demonstrates that these organelles are not absolutely essential to eukaryotic cells. However, the degree to which the metabolism and cellular systems of this organism have adapted to the loss of mitochondria is unknown. Here we report an extensive analysis of the...
Article
Full-text available
The discovery that the protist Monocercomonoides exilis completely lacks mitochondria demonstrates that these organelles are not absolutely essential to eukaryotic cells. However, the degree to which the metabolism and cellular systems of this organism have adapted to the loss of mitochondria is unknown. Here we report an extensive analysis of the...
Preprint
Full-text available
Euglena gracilis is a well-studied biotechnologically exploitable phototrophic flagellate harbouring secondary green plastids. Here we describe its plastid proteome obtained by high-resolution proteomics. We identified 1,345 candidate plastid proteins and assigned functional annotations to 774 of them. More than 120 proteins are affiliated neither...
Article
Full-text available
Background: Photosynthetic euglenids are major contributors to fresh water ecosystems. Euglena gracilis in particular has noted metabolic flexibility, reflected by an ability to thrive in a range of harsh environments. E. gracilis has been a popular model organism and of considerable biotechnological interest, but the absence of a gene catalogue h...
Article
Arguments based on cell energetics favour the view that a mitochondrion capable of oxidative phosphorylation was a prerequisite for the evolution of other features of the eukaryotic cell, including increased volume, genome size and, eventually, phagotrophy. Contrary to this we argue that: (i) extant amitochondriate eukaryotes possess voluminous pha...
Article
Full-text available
This revision of the classification of eukaryotes follows that of Adl et al., 2012 [J. Euk. Microbiol. 59(5)] and retains an emphasis on protists. Changes since have improved the resolution of many nodes in phylogenetic analyses. For some clades even families are being clearly resolved. As we had predicted, environmental sampling in the intervening...
Article
Full-text available
The oxymonad Monocercomonoides exilis was recently reported to be the first eukaryote that has completely lost the mitochondrial compartment. It was proposed that an important prerequisite for such a radical evolutionary step was the acquisition of the SUF Fe-S cluster assembly pathway from prokaryotes, making the mitochondrial ISC pathway dispensa...
Article
Oxymonads are a group of flagellates living as gut symbionts of insects or vertebrates. They have several unique features, one of them being the absence of mitochondria. Diversity of this group is seriously understudied, which is particularly true for small species from the family Polymastigidae. We isolated 34 strains of oxymonads with Polymastigi...
Article
Full-text available
Chloroplasts are generally known as eukaryotic organelles whose main function is photosynthesis. They perform other functions, however, such as synthesizing isoprenoids, fatty acids, heme, iron sulphur clusters and other essential compounds. In non-photosynthetic lineages that possess plastids, the chloroplast genomes have been reduced and most (or...
Article
Full-text available
Rheb is a conserved and widespread Ras-like GTPase involved in cell growth regulation mediated by the (m)TORC1 kinase complex and implicated in tumourigenesis in humans. Rheb function depends on its association with membranes via prenylated C-terminus, a mechanism shared with many other eukaryotic GTPases. Strikingly, our analysis of a phylogenetic...
Preprint
Full-text available
Photosynthetic euglenids are major components of aquatic ecosystems and relatives of trypanosomes. Euglena gracilis has considerable biotechnological potential and great adaptability, but exploitation remains hampered by the absence of a comprehensive gene catalogue. We address this by genome, RNA and protein sequencing: the E. gracilis genome is >...
Chapter
Preaxostyla comprises Oxymonadida, containing 14 genera of gut endosymbionts plus two genera of free-living bacterivorous flagellates from low oxygen sediments (Trimastix and Paratrimastix). The group was recognized on the basis of 18S rRNA phylogenies, and ultrastructural investigations have revealed a synapomorphy in the organization of the “I” f...
Chapter
Euglenophytes obtained their plastids from a primary green alga related to extant genus Pyramimonas. The relatively recent establishment of this new organelle is an intriguing evolutionary phenomenon worth studying and comparing with other secondary plastids with a regard to their similarities and differences. A remarkably fast evolution driven by...
Chapter
The concept of a phylogeny of parasites is inextricably linked to that of the phylogeny of eukaryotes. Though it can be useful to infer functional principles from similar morphologies and trophic strategies, the evolutionary histories of parasites are most accurately viewed as independent shifts to this lifestyle from a free-living state. This chap...
Article
Full-text available
Background Multiple prokaryotic lineages use the arginine deiminase (ADI) pathway for anaerobic energy production by arginine degradation. The distribution of this pathway among eukaryotes has been thought to be very limited, with only two specialized groups living in low oxygen environments (Parabasalia and Diplomonadida) known to possess the comp...
Article
Full-text available
Due to their involvement in the energy metabolism, mitochondria are essential for most eukaryotic cells. Microbial eukaryotes living in low oxygen environments possess reduced forms of mitochondria, namely mitochondrion-related organelles (MROs). These do not produce ATP by oxidative phosphorylation on their membranes and some do not produce ATP at...
Article
Prasinophytes are a paraphyletic assemblage of nine heterogeneous lineages in the Chlorophyta clade of Archaeplastida. Until now, seven complete mitochondrial genomes have been sequenced from four prasinophyte lineages. Here we report the mitochondrial genome of Pyramimonas parkeae, the first respresentative of the prasinophyte clade I. The circula...
Article
Full-text available
The presence of mitochondria and related organelles in every studied eukaryote supports the view that mitochondria are essential cellular components. Here, we report the genome sequence of a microbial eukaryote, the oxymonad Monocercomonoides sp., which revealed that this organism lacks all hallmark mitochondrial proteins. Crucially, the mitochondr...
Article
Full-text available
Historically, there were several classification schemes of eukaryotes, always reflecting the contemporary state of knowledge. The article presents the major stages and milestones in its development, including the current concept of eukaryotic supergroups. Considering its significance, the possible implementation of this approach in secondary school...
Article
In this review the main features of the mitochondria of aerobic parasitic protists are discussed. While the best characterized organelles are by far those of kinetoplastid flagellates and Plasmodium, we also consider amoebae Naegleria and Acanthamoeba, a ciliate Ichthyophthirius and related lineages. The simplistic view of the mitochondrion as just...
Chapter
Full-text available
Preaxostyla comprises Oxymonadida, containing 14 genera of gut endosymbionts plus two genera of free-living bacterivorous flagellates from low oxygen sediments (Trimastix and Paratrimastix). The group was recognized on the 18S rRNA phylogenies, and ultrastructural investigations have revealed a synapomorphy in the organization of the “I” fiber that...
Article
Mitochondrial evolution entailed the origin of protein import machinery that allows nuclear-encoded proteins to be targeted to the organelle, as well as the origin of cleavable N-terminal targeting sequences (NTS) that allow efficient sorting and import of matrix proteins. In hydrogenosomes and mitosomes, reduced forms of mitochondria with reduced...
Article
We report the light-microscopic morphology and ultrastructure of a novel free-living, heterotrophic protist, Creneis carolina gen. et sp. nov. isolated from marine anoxic sediments. C. carolina is a heterotrophic, obligately anaerobic amoeboid flagellate, and superficially resembles Mastigamoeba (Amoebozoa: Archamoebae) or Breviata (Breviatea) by p...
Article
Full-text available
Methionine adenosyltransferase (MAT) is a ubiquitous essential enzyme that, in eukaryotes, occurs in two relatively divergent paralogues: MAT and MATX. MATX has a punctate distribution across the tree of eukaryotes and, except for a few cases, is mutually exclusive with MAT. This phylogenetic pattern could have arisen by either differential loss of...
Article
Full-text available
All eukaryotic organisms contain mitochondria or organelles that evolved from the same endosymbiotic event like classical mitochondria. Organisms inhabiting low oxygen environments often contain mitochondrial derivates known as hydrogenosomes, mitosomes or neutrally as mitochondrion-like organelles. The detailed investigation has shown unexpected e...
Data
Full-text available
The N-terminal parts of protein alignments demonstrating the presence of extension in Trimastix protein relatively to the prokaryotic homologues. (PDF)
Data
The probability of mitochondrial localization of selected Trimastix proteins as predicted by PSORT II, TargetP and Multiloc2 programs. (DOCX)
Data
Full-text available