An autotrophic unarmored dinoflagellate species with haptophyte-derived plastids, Kapelodiniopsis flava n. g., n. sp., was described as a sister taxon of Kapelodinium vestifici, which was formerly well characterized by its low-positioned cingulum and heterotrophic nature. The isolates from several Japanese coastal locations were observed using light microscopy, scanning and transmission electron microscopy, and their phylogeny was inferred from nuclear-encoded rRNA genes and multiple plastid-encoded genes. To date of this publication, a representative culture of Ks. flava has grown autotrophically for 98 months in the absence of prey or organic matter. This dinoflagellate lacked nonplastid haptophyte cell components (e.g. nucleus or mitochondria). In the host dinoflagellate phylogeny, Ks. flava was distantly related to the other two dinoflagellate lineages known to be associated with haptophyte-derived plastids, thus representing the third of such lineage. Plastid origins differed among Ks. flava strains (>99.8% 18S rRNA gene identity), with plastids being derived from at least three haptophytes and an especially strong genetic similarity to two distantly related extant haptophytes (>99.9% 16S rRNA gene identity). This indicates that Ks. flava recently integrated plastids from multiple haptophyte lineages to an extent that allows the host to replicate the plastids without other haptophyte components.

• Klíčová slova
• Katodinium, culture, endosymbiosis, kleptoplastidy, molecular phylogeny, plastid membranes, plastid replacement, relic plastid, taxonomy, ultrastructure,
• MeSH
• Dinoflagellata * genetika   klasifikace   ultrastruktura   izolace a purifikace   MeSH
• fylogeneze MeSH
• Haptophyta * genetika   ultrastruktura   MeSH
• plastidy * genetika   ultrastruktura   MeSH
• protozoální DNA genetika   chemie   MeSH
• ribozomální DNA genetika   chemie   MeSH
• RNA ribozomální 18S genetika   MeSH
• sekvenční analýza DNA MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Japonsko MeSH
• Názvy látek
• protozoální DNA MeSH
• ribozomální DNA MeSH
• RNA ribozomální 18S MeSH

A substantial portion of eukaryote diversity consists of algae with complex plastids, i.e., plastids originating from eukaryote-to-eukaryote endosymbioses. These plastids are characteristic by a deviating number of envelope membranes (higher than two), and sometimes a remnant nucleus of the endosymbiont alga, termed the nucleomorph, is present. Complex plastid-bearing algae are therefore much like living matryoshka dolls, eukaryotes within eukaryotes. In comparison, primary plastids of Archaeplastida (plants, green algae, red algae, and glaucophytes) arose upon a single endosymbiosis event with a cyanobacterium and are surrounded by two membranes. Complex plastids were acquired several times by unrelated groups nested within eukaryotic heterotrophs, suggesting complex plastids are somewhat easier to obtain than primary plastids. This is consistent with the existence of higher-order and serial endosymbioses, i.e., engulfment of complex plastid-bearing algae by (tertiary) eukaryotic hosts and functional plastid replacements, respectively. Plastid endosymbiosis is typical by a massive transfer of genetic material from the endosymbiont to the host nucleus and metabolic rearrangements related to the trophic switch to phototrophy; this is necessary to establish metabolic integration of the plastid and control over its division. Although photosynthesis is the main advantage of plastid acquisition, algae that lost photosynthesis often maintain complex plastids, suggesting their roles beyond photosynthesis. This chapter summarizes basic knowledge on acquisition and functions of complex plastid.

• Klíčová slova
• Complex endosymbiosis, Plastid replacement, Reductive evolution,
• MeSH
• biologická evoluce MeSH
• Eukaryota klasifikace   genetika   metabolismus   MeSH
• fotosyntéza MeSH
• plastidy genetika   metabolismus   MeSH
• symbióza * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

A considerable part of the diversity of eukaryotic phototrophs consists of algae with plastids that evolved from endosymbioses between two eukaryotes. These complex plastids are characterized by a high number of envelope membranes (more than two) and some of them contain a residual nucleus of the endosymbiotic alga called a nucleomorph. Complex plastid-bearing algae are thus chimeric cell assemblies, eukaryotic symbionts living in a eukaryotic host. In contrast, the primary plastids of the Archaeplastida (plants, green algae, red algae, and glaucophytes) possibly evolved from a single endosymbiosis with a cyanobacterium and are surrounded by two membranes. Complex plastids have been acquired several times by unrelated groups of eukaryotic heterotrophic hosts, suggesting that complex plastids are somewhat easier to obtain than primary plastids. Evidence suggests that complex plastids arose twice independently in the green lineage (euglenophytes and chlorarachniophytes) through secondary endosymbiosis, and four times in the red lineage, first through secondary endosymbiosis in cryptophytes, then by higher-order events in stramenopiles, alveolates, and haptophytes. Engulfment of primary and complex plastid-containing algae by eukaryotic hosts (secondary, tertiary, and higher-order endosymbioses) is also responsible for numerous plastid replacements in dinoflagellates. Plastid endosymbiosis is accompanied by massive gene transfer from the endosymbiont to the host nucleus and cell adaptation of both endosymbiotic partners, which is related to the trophic switch to phototrophy and loss of autonomy of the endosymbiont. Such a process is essential for the metabolic integration and division control of the endosymbiont in the host. Although photosynthesis is the main advantage of acquiring plastids, loss of photosynthesis often occurs in algae with complex plastids. This chapter summarizes the essential knowledge of the acquisition, evolution, and function of complex plastids.

• Klíčová slova
• Complex endosymbiosis, Plastid replacement, Reductive evolution,
• MeSH
• biologická evoluce * MeSH
• fylogeneze MeSH
• plastidy genetika   metabolismus   MeSH
• Rhodophyta * genetika   MeSH
• rostliny genetika   MeSH
• symbióza MeSH
• Publikační typ
• časopisecké články MeSH

Euglenophytes are a familiar algal group with green alga-derived secondary plastids, but the knowledge of euglenophyte plastid function and evolution is still highly incomplete. With this in mind we sequenced and analysed the transcriptome of the non-photosynthetic species Euglena longa. The transcriptomic data confirmed the absence of genes for the photosynthetic machinery, but provided candidate plastid-localised proteins bearing N-terminal bipartite topogenic signals (BTSs) of the characteristic euglenophyte type. Further comparative analyses including transcriptome assemblies available for photosynthetic euglenophytes enabled us to unveil salient aspects of the basic euglenophyte plastid infrastructure, such as plastidial targeting of several proteins as C-terminal translational fusions with other BTS-bearing proteins or replacement of the conventional eubacteria-derived plastidial ribosomal protein L24 by homologs of archaeo-eukaryotic origin. Strikingly, no homologs of any key component of the TOC/TIC system and the plastid division apparatus are discernible in euglenophytes, and the machinery for intraplastidial protein targeting has been simplified by the loss of the cpSRP/cpFtsY system and the SEC2 translocon. Lastly, euglenophytes proved to encode a plastid-targeted homolog of the termination factor Rho horizontally acquired from a Lambdaproteobacteria-related donor. Our study thus further documents a substantial remodelling of the euglenophyte plastid compared to its green algal progenitor.

• MeSH
• Euglena longa klasifikace   cytologie   genetika   MeSH
• fotosyntéza * MeSH
• fylogeneze MeSH
• molekulární evoluce * MeSH
• plastidy genetika   MeSH
• proteiny chloroplastové genetika   MeSH
• sekvence nukleotidů MeSH
• sekvenční homologie MeSH
• stanovení celkové genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• proteiny chloroplastové MeSH

Tetrapyrroles such as chlorophyll and heme are indispensable for life because they are involved in energy fixation and consumption, i.e. photosynthesis and oxidative phosphorylation. In eukaryotes, the tetrapyrrole biosynthetic pathway is shaped by past endosymbioses. We investigated the origins and predicted locations of the enzymes of the heme pathway in the chlorarachniophyte Bigelowiella natans, the cryptophyte Guillardia theta, the "green" dinoflagellate Lepidodinium chlorophorum, and three dinoflagellates with diatom endosymbionts ("dinotoms"): Durinskia baltica, Glenodinium foliaceum and Kryptoperidinium foliaceum. Bigelowiella natans appears to contain two separate heme pathways analogous to those found in Euglena gracilis; one is predicted to be mitochondrial-cytosolic, while the second is predicted to be plastid-located. In the remaining algae, only plastid-type tetrapyrrole synthesis is present, with a single remnant of the mitochondrial-cytosolic pathway, a ferrochelatase of G. theta putatively located in the mitochondrion. The green dinoflagellate contains a single pathway composed of mostly rhodophyte-origin enzymes, and the dinotoms hold two heme pathways of apparently plastidal origin. We suggest that heme pathway enzymes in B. natans and L. chlorophorum share a predominantly rhodophytic origin. This implies the ancient presence of a rhodophyte-derived plastid in the chlorarachniophyte alga, analogous to the green dinoflagellate, or an exceptionally massive horizontal gene transfer.

• MeSH
• biologická evoluce * MeSH
• biosyntetické dráhy * genetika   MeSH
• Cryptophyta klasifikace   genetika   metabolismus   MeSH
• Dinoflagellata klasifikace   genetika   metabolismus   MeSH
• fylogeneze MeSH
• hem metabolismus   MeSH
• porfobilinogensynthasa genetika   metabolismus   MeSH
• rozsivky klasifikace   genetika   metabolismus   MeSH
• stanovení celkové genové exprese MeSH
• tetrapyrroly metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hem MeSH
• porfobilinogensynthasa MeSH
• tetrapyrroly MeSH

Dinoflagellates are a diverse group of ecologically significant micro-eukaryotes that can serve as a model system for plastid symbiogenesis due to their susceptibility to plastid loss and replacement via serial endosymbiosis. Kareniaceae harbor fucoxanthin-pigmented plastids instead of the ancestral peridinin-pigmented ones and support them with a diverse range of nucleus-encoded plastid-targeted proteins originating from the haptophyte endosymbiont, dinoflagellate host, and/or lateral gene transfers (LGT). Here, we present predicted plastid proteomes from seven distantly related kareniaceans in three genera (Karenia, Karlodinium, and Takayama) and analyze their evolutionary patterns using automated tree building and sorting. We project a relatively limited ( ~ 10%) haptophyte signal pointing towards a shared origin in the family Chrysochromulinaceae. Our data establish significant variations in the functional distributions of these signals, emphasizing the importance of micro-evolutionary processes in shaping the chimeric proteomes. Analysis of plastid genome sequences recontextualizes these results by a striking finding the extant kareniacean plastids are in fact not all of the same origin, as two of the studied species (Karlodinium armiger, Takayama helix) possess plastids from different haptophyte orders than the rest.

• Klíčová slova
• Automated Tree Sorting, Myzozoa, Post-Endosymbiotic Organelle Evolution, Protists, Shopping Bag Model,
• MeSH
• Dinoflagellata * genetika   metabolismus   MeSH
• fylogeneze MeSH
• plastidy genetika   MeSH
• proteom genetika   metabolismus   MeSH
• symbióza genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• proteom MeSH

Trypanosomatids of the subfamily Strigomonadinae bear permanent intracellular bacterial symbionts acquired by the common ancestor of these flagellates. However, the cospeciation pattern inherent to such relationships was revealed to be broken upon the description of Angomonas ambiguus, which is sister to A. desouzai, but bears an endosymbiont genetically close to that of A. deanei. Based on phylogenetic inferences, it was proposed that the bacterium from A. deanei had been horizontally transferred to A. ambiguus. Here, we sequenced the bacterial genomes from two A. ambiguus isolates, including a new one from Papua New Guinea, and compared them with the published genome of the A. deanei endosymbiont, revealing differences below the interspecific level. Our phylogenetic analyses confirmed that the endosymbionts of A. ambiguus were obtained from A. deanei and, in addition, demonstrated that this occurred more than once. We propose that coinfection of the same blowfly host and the phylogenetic relatedness of the trypanosomatids facilitate such transitions, whereas the drastic difference in the occurrence of the two trypanosomatid species determines the observed direction of this process. This phenomenon is analogous to organelle (mitochondrion/plastid) capture described in multicellular organisms and, thereafter, we name it endosymbiont capture.

• Klíčová slova
• Angomonas, Trypanosomatidae, bacterial endosymbionts, genome,
• Publikační typ
• časopisecké články MeSH

In most eukaryotic phototrophs, the entire heme synthesis is localized to the plastid, and enzymes of cyanobacterial origin dominate the pathway. Despite that, porphobilinogen deaminase (PBGD), the enzyme responsible for the synthesis of hydroxymethybilane in the plastid, shows phylogenetic affiliation to α-proteobacteria, the supposed ancestor of mitochondria. Surprisingly, no PBGD of such origin is found in the heme pathway of the supposed partners of the primary plastid endosymbiosis, a primarily heterotrophic eukaryote, and a cyanobacterium. It appears that α-proteobacterial PBGD is absent from glaucophytes but is present in rhodophytes, chlorophytes, plants, and most algae with complex plastids. This may suggest that in eukaryotic phototrophs, except for glaucophytes, either the gene from the mitochondrial ancestor was retained while the cyanobacterial and eukaryotic pseudoparalogs were lost in evolution, or the gene was acquired by non-endosymbiotic gene transfer from an unspecified α-proteobacterium and functionally replaced its cyanobacterial and eukaryotic counterparts.

• Klíčová slova
• evolution, gene replacement, heme biosynthesis, horizontal gene transfer, hydroxymethylbilane synthase, mitochondrion, porphobilinogen deaminase,
• Publikační typ
• časopisecké články MeSH

In response to a comment in this issue on our proposal of new terminology to distinguish red algal parasites, we clarify a few key issues. The terms adelphoparasite and alloparasite were previously used to identify parasites that infected close or distant relatives. However, most red algal parasites have only been studied morphologically, and molecular tools have shown that these binary terms do a poor job at representing the range of parasite-host relationships. We recognize the need to clarify inferred misconceptions that appear to be drawing from historical terminology to contaminate our new definitions. We did not intend to replace the term adelphoparasite with neoplastic parasites and the term alloparasites with archaeplastic parasites. Rather, we seek to establish new terms for discussing red algal parasites, based on the retention of a native plastid, a binary biological trait that is relatively easy to identify using modern methods and has biological implications for the interactions between a parasite and its host. The new terminology can better account for the spectrum of relationships and developmental patterns found among the many independently evolved red algal parasites, and it is intended to inspire new research, particularly the role of plastids in the survival and evolution of red algal parasites.

• Klíčová slova
• Rhodophyta, adelphoparasite, alloparasite, archaeplastic, neoplastic, symbiosis, taxonomy,
• MeSH
• fylogeneze MeSH
• paraziti * MeSH
• plastidy MeSH
• Rhodophyta * MeSH
• symbióza MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Bacterial division initiates at the site of a contractile Z-ring composed of polymerized FtsZ. The location of the Z-ring in the cell is controlled by a system of three mutually antagonistic proteins, MinC, MinD, and MinE. Plastid division is also known to be dependent on homologs of these proteins, derived from the ancestral cyanobacterial endosymbiont that gave rise to plastids. In contrast, the mitochondria of model systems such as Saccharomyces cerevisiae, mammals, and Arabidopsis thaliana seem to have replaced the ancestral α-proteobacterial Min-based division machinery with host-derived dynamin-related proteins that form outer contractile rings. Here, we show that the mitochondrial division system of these model organisms is the exception, rather than the rule, for eukaryotes. We describe endosymbiont-derived, bacterial-like division systems comprising FtsZ and Min proteins in diverse less-studied eukaryote protistan lineages, including jakobid and heterolobosean excavates, a malawimonad, stramenopiles, amoebozoans, a breviate, and an apusomonad. For two of these taxa, the amoebozoan Dictyostelium purpureum and the jakobid Andalucia incarcerata, we confirm a mitochondrial localization of these proteins by their heterologous expression in Saccharomyces cerevisiae. The discovery of a proteobacterial-like division system in mitochondria of diverse eukaryotic lineages suggests that it was the ancestral feature of all eukaryotic mitochondria and has been supplanted by a host-derived system multiple times in distinct eukaryote lineages.

• Klíčová slova
• Min proteins, MinCDE, mitochondria, mitochondrial division, mitochondrial fission,
• MeSH
• adenosintrifosfatasy metabolismus   MeSH
• Arabidopsis genetika   MeSH
• Bacteria cytologie   MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• buněčné dělení MeSH
• cytoskeletální proteiny genetika   MeSH
• databáze genetické MeSH
• Dictyostelium metabolismus   MeSH
• DNA bakterií genetika   MeSH
• fylogeneze MeSH
• mitochondriální dynamika * MeSH
• mitochondrie metabolismus   MeSH
• molekulární evoluce MeSH
• molekulární sekvence - údaje MeSH
• plastidy metabolismus   MeSH
• pravděpodobnostní funkce MeSH
• proteiny buněčného cyklu metabolismus   MeSH
• proteiny z Escherichia coli metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• sekvence nukleotidů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosintrifosfatasy MeSH
• bakteriální proteiny MeSH
• cytoskeletální proteiny MeSH
• DNA bakterií MeSH
• FtsZ protein, Bacteria MeSH Prohlížeč
• MinC protein, Bacteria MeSH Prohlížeč
• MinD protein, E coli MeSH Prohlížeč
• MinE protein, E coli MeSH Prohlížeč
• proteiny buněčného cyklu MeSH
• proteiny z Escherichia coli MeSH