BACKGROUND: Comparing a parasitic lineage to its free-living relatives is a powerful way to understand how that evolutionary transition to parasitism occurred. Giardia intestinalis (Fornicata) is a leading cause of gastrointestinal disease world-wide and is famous for its unusual complement of cellular compartments, such as having peripheral vacuoles instead of typical endosomal compartments. Endocytosis plays an important role in Giardia's pathogenesis. Endosomal sorting complexes required for transport (ESCRT) are membrane-deforming proteins associated with the late endosome/multivesicular body (MVB). MVBs are ill-defined in G. intestinalis, and roles for identified ESCRT-related proteins are not fully understood in the context of its unique endocytic system. Furthermore, components thought to be required for full ESCRT functionality have not yet been documented in this species. RESULTS: We used genomic and transcriptomic data from several Fornicata species to clarify the evolutionary genome streamlining observed in Giardia, as well as to detect any divergent orthologs of the Fornicata ESCRT subunits. We observed differences in the ESCRT machinery complement between Giardia strains. Microscopy-based investigations of key components of ESCRT machinery such as GiVPS36 and GiVPS25 link them to peripheral vacuoles, highlighting these organelles as simplified MVB equivalents. Unexpectedly, we show ESCRT components associated with the endoplasmic reticulum and, for the first time, mitosomes. Finally, we identified the rare ESCRT component CHMP7 in several fornicate representatives, including Giardia and show that contrary to current understanding, CHMP7 evolved from a gene fusion of VPS25 and SNF7 domains, prior to the last eukaryotic common ancestor, over 1.5 billion years ago. CONCLUSIONS: Our findings show that ESCRT machinery in G. intestinalis is far more varied and complete than previously thought, associates to multiple cellular locations, and presents changes in ESCRT complement which pre-date adoption of a parasitic lifestyle.

• MeSH
• biologická evoluce MeSH
• endozomální třídící komplexy pro transport * genetika   metabolismus   MeSH
• endozomy metabolismus   MeSH
• Giardia lamblia * genetika   metabolismus   MeSH
• transport proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The Brassicaceae include several major crop plants and numerous important model species in comparative evolutionary research such as Arabidopsis, Brassica, Boechera, Thellungiella, and Arabis species. As any evolutionary hypothesis needs to be placed in a temporal context, reliably dated major splits within the evolution of Brassicaceae are essential. We present a comprehensive time-calibrated framework with important divergence time estimates based on whole-chloroplast sequence data for 29 Brassicaceae species. Diversification of the Brassicaceae crown group started at the Eocene-to-Oligocene transition. Subsequent major evolutionary splits are dated to ∼20 million years ago, coinciding with the Oligocene-to-Miocene transition, with increasing drought and aridity and transient glaciation events. The age of the Arabidopsis thaliana crown group is 6 million years ago, at the Miocene and Pliocene border. The overall species richness of the family is well explained by high levels of neopolyploidy (43% in total), but this trend is neither directly associated with an increase in genome size nor is there a general lineage-specific constraint. Our results highlight polyploidization as an important source for generating new evolutionary lineages adapted to changing environments. We conclude that species radiation, paralleled by high levels of neopolyploidization, follows genome size decrease, stabilization, and genetic diploidization.

• MeSH
• Arabidopsis genetika   fyziologie   MeSH
• Brassica genetika   fyziologie   MeSH
• Brassicaceae genetika   fyziologie   MeSH
• fylogeneze MeSH
• genom chloroplastový genetika   MeSH
• genom rostlinný genetika   MeSH
• molekulární evoluce * MeSH
• polyploidie MeSH
• sekvenční analýza DNA MeSH
• vznik druhů (genetika) MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Blastocystis is the most prevalent microbial eukaryote in the human and animal gut, yet its role as commensal or parasite is still under debate. Blastocystis has clearly undergone evolutionary adaptation to the gut environment and possesses minimal cellular compartmentalization, reduced anaerobic mitochondria, no flagella, and no reported peroxisomes. To address this poorly understood evolutionary transition, we have taken a multi-disciplinary approach to characterize Proteromonas lacertae, the closest canonical stramenopile relative of Blastocystis. Genomic data reveal an abundance of unique genes in P. lacertae but also reductive evolution of the genomic complement in Blastocystis. Comparative genomic analysis sheds light on flagellar evolution, including 37 new candidate components implicated with mastigonemes, the stramenopile morphological hallmark. The P. lacertae membrane-trafficking system (MTS) complement is only slightly more canonical than that of Blastocystis, but notably, we identified that both organisms encode the complete enigmatic endocytic TSET complex, a first for the entire stramenopile lineage. Investigation also details the modulation of mitochondrial composition and metabolism in both P. lacertae and Blastocystis. Unexpectedly, we identify in P. lacertae the most reduced peroxisome-derived organelle reported to date, which leads us to speculate on a mechanism of constraint guiding the dynamics of peroxisome-mitochondrion reductive evolution on the path to anaerobiosis. Overall, these analyses provide a launching point to investigate organellar evolution and reveal in detail the evolutionary path that Blastocystis has taken from a canonical flagellated protist to the hyper-divergent and hyper-prevalent animal and human gut microbe.

• MeSH
• Blastocystis * genetika   MeSH
• Eukaryota MeSH
• lidé MeSH
• mitochondrie genetika   metabolismus   MeSH
• organely metabolismus   MeSH
• střevní mikroflóra * genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The most abundant aquatic microbes are small in cell and genome size. Genome-streamlining theory predicts gene loss caused by evolutionary selection driven by environmental factors, favouring superior competitors for limiting resources. However, evolutionary histories of such abundant, genome-streamlined microbes remain largely unknown. Here we reconstruct the series of steps in the evolution of some of the most abundant genome-streamlined microbes in freshwaters ("Ca. Methylopumilus") and oceans (marine lineage OM43). A broad genomic spectrum is visible in the family Methylophilaceae (Betaproteobacteria), from sediment microbes with medium-sized genomes (2-3 Mbp genome size), an occasionally blooming pelagic intermediate (1.7 Mbp), and the most reduced pelagic forms (1.3 Mbp). We show that a habitat transition from freshwater sediment to the relatively oligotrophic pelagial was accompanied by progressive gene loss and adaptive gains. Gene loss has mainly affected functions not necessarily required or advantageous in the pelagial or is encoded by redundant pathways. Likewise, we identified genes providing adaptations to oligotrophic conditions that have been transmitted horizontally from pelagic freshwater microbes. Remarkably, the secondary transition from the pelagial of lakes to the oceans required only slight modifications, i.e., adaptations to higher salinity, gained via horizontal gene transfer from indigenous microbes. Our study provides first genomic evidence of genome reduction taking place during habitat transitions. In this regard, the family Methylophilaceae is an exceptional model for tracing the evolutionary history of genome streamlining as such a collection of evolutionarily related microbes from different habitats is rare in the microbial world.

• MeSH
• délka genomu MeSH
• ekosystém * MeSH
• fylogeneze MeSH
• fyziologická adaptace MeSH
• genom bakteriální * MeSH
• geologické sedimenty mikrobiologie   MeSH
• jezera mikrobiologie   MeSH
• Methylophilaceae klasifikace   genetika   izolace a purifikace   fyziologie   MeSH
• molekulární evoluce MeSH
• mořská voda mikrobiologie   MeSH
• přenos genů horizontální MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Photosynthesis in plants and algae relies on the coordinated function of photosystems (PS) I and II. Their efficiency is augmented by finely-tuned light-harvesting proteins (Lhcs) connected to them. The most recent Lhcs (in evolutionary terms), Lhcb6 and Lhcb3, evolved during the transition of plants from water to land and have so far been considered to be an essential characteristic of land plants. We used single particle electron microscopy and sequence analysis to study architecture and composition of PSII supercomplex from Norway spruce and related species. We have found that there are major land plant families that lack functional lhcb6 and lhcb3 genes, which notably changes the organization of PSII supercomplexes. The Lhcb6 and Lhcb3 proteins have been lost in the gymnosperm genera Picea and Pinus (family Pinaceae) and Gnetum (Gnetales). We also revealed that the absence of these proteins in Norway spruce modifies the PSII supercomplex in such a way that it resembles its counterpart in the alga Chlamydomonas reinhardtii, an evolutionarily older organism. Our results break a deep-rooted concept of Lhcb6 and Lhcb3 proteins being the essential characteristic of land plants, and beg the question of what the evolutionary benefit of their loss could be.

• MeSH
• biologická evoluce * MeSH
• fotosystém II (proteinový komplex) metabolismus   MeSH
• fylogeneze MeSH
• podjednotky proteinů chemie   metabolismus   MeSH
• rostlinné geny MeSH
• rostlinné proteiny metabolismus   MeSH
• sekvenční homologie aminokyselin MeSH
• světlosběrné proteinové komplexy metabolismus   ultrastruktura   MeSH
• vyšší rostliny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Apicomplexans and related lineages comprise many obligate symbionts of animals; some of which cause notorious diseases such as malaria. They evolved from photosynthetic ancestors and transitioned into a symbiotic lifestyle several times, giving rise to species with diverse non-photosynthetic plastids. Here, we sought to reconstruct the evolution of the cryptic plastids in the apicomplexans, chrompodellids, and squirmids (ACS clade) by generating five new single-cell transcriptomes from understudied gregarine lineages, constructing a robust phylogenomic tree incorporating all ACS clade sequencing datasets available, and using these to examine in detail, the evolutionary distribution of all 162 proteins recently shown to be in the apicoplast by spatial proteomics in Toxoplasma. This expanded homology-based reconstruction of plastid proteins found in the ACS clade confirms earlier work showing convergence in the overall metabolic pathways retained once photosynthesis is lost, but also reveals differences in the degrees of plastid reduction in specific lineages. We show that the loss of the plastid genome is common and unexpectedly find many lineage- and species-specific plastid proteins, suggesting the presence of evolutionary innovations and neofunctionalizations that may confer new functional and metabolic capabilities that are yet to be discovered in these enigmatic organelles.

• MeSH
• fotosyntéza genetika   MeSH
• fylogeneze MeSH
• metabolické sítě a dráhy MeSH
• plastidy * genetika   MeSH
• proteom * genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Game theoretic models of evolution such as the Hawk-Dove game assume that individuals gain fitness (which is a proxy of the per capita population growth rate) in pair-wise contests only. These models assume that the equilibrium distribution of phenotypes involved (e.g., Hawks and Doves) in the population is given by the Hardy-Weinberg law, which is based on instantaneous, random pair formation. On the other hand, models of population dynamics do not consider pairs, newborns are produced by singles, and interactions between phenotypes or species are described by the mass action principle. This article links game theoretic and population approaches. It shows that combining distribution dynamics with population dynamics can lead to stable coexistence of Hawk and Dove population numbers in models that do not assume a priori that fitness is negative density dependent. Our analysis shows clearly that the interior Nash equilibrium of the Hawk and Dove model depends both on population size and on interaction times between different phenotypes in the population. This raises the question of the applicability of classic evolutionary game theory that requires all interactions take the same amount of time and that all single individuals have the same payoff per unit of time, to real populations. Furthermore, by separating individual fitness into birth and death effects on singles and pairs, it is shown that stable coexistence in these models depends on the time-scale of the distribution dynamics relative to the population dynamics. When explicit density-dependent fitness is included through competition over a limited resource, the combined dynamics of the Hawk-Dove model often lead to Dove extinction no matter how costly fighting is for Hawk pairs.

• MeSH
• biologická evoluce * MeSH
• biologické modely * MeSH
• populační dynamika MeSH
• teorie her MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Most bacteria are found either in marine or fresh waters and transitions between the two habitats are rare, even though freshwater and marine bacteria co-occur in brackish habitats. Estuaries in brackish, tideless seas could be habitats where the transition of freshwater phylotypes to marine conditions occurs. We tested this hypothesis in the Gulf of Gdańsk (Baltic Sea) by comparing bacterial communities from different zones of the estuary, via pyrosequencing of 16S rRNA amplicons. We predicted the existence of a core microbiome (CM, a set of abundant OTUs present in all samples) comprising OTUs consisting of populations specific for particular zones of the estuary. The CMs for the entire studied period consisted of only eight OTUs, and this number was even lower for specific seasons: five in spring, two in summer, and one in autumn and winter. Six of the CM OTUs, and another 21 of the 50 most abundant OTUs consisted of zone-specific populations, plausibly representing micro-evolutionary forces. The presence of up to 15% of freshwater phylotypes from the Vistula River in the brackish Gulf of Gdańsk supported our hypothesis, but high dissimilarity between the bacterial communities suggested that freshwater-marine transitions are rare even in tideless estuaries in brackish seas.

• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• bakteriální RNA genetika   MeSH
• estuár * MeSH
• mořská voda mikrobiologie   MeSH
• ribozomální DNA chemie   genetika   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• sladká voda mikrobiologie   MeSH
• společenstvo * MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: During amphibian metamorphosis, the crucial moment lies in the rearrangement of the heart, reflecting the changes in circulatory demands. However, little is known about the exact shifts linked with this rearrangement. Here, we demonstrate such myocardial changes in axolotl (Ambystoma mexicanum) from the morphological and physiological point of view. RESULTS: Micro-CT and histological analysis showed changes in ventricular trabeculae organization, completion of the atrial septum and its connection to the atrioventricular valve. Based on Myosin Heavy Chain and Smooth Muscle Actin expression we distinguished metamorphosis-induced changes in myocardial differentiation at the ventricular trabeculae and atrioventricular canal. Using optical mapping, faster speed of conduction through the atrioventricular canal was demonstrated in metamorphic animals. No differences between the groups were observed in the heart rates, ventricular activation times, and activation patterns. CONCLUSIONS: Transition from aquatic to terrestrial life-style is reflected in the heart morphology and function. Rebuilding of the axolotl heart during metamorphosis was connected with reorganization of ventricular trabeculae, completion of the atrial septum and its connection to the atrioventricular valve, and acceleration of AV conduction.

• MeSH
• Ambystoma mexicanum * fyziologie   MeSH
• biologická evoluce MeSH
• biologická proměna fyziologie   MeSH
• myokard MeSH
• srdce * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Simple mathematical models were constructed (using a DEC PDP 11/40 computer) to evaluate the probable significance of differences between individuals in adaptive reserve--survival time (modelled as "failure rate")--for group survival and of basic population parameters (fertility and mortality) for the gradual compensation of group size/age distribution of a population after an acute group disaster. The results indicate that reversion to prehuman biological regulative mechanisms probably occurs, and that after short-lasting group disasters the time-course for compensation (normalization) of population size and age distribution (when probable values of fertility and mortality were considered) is prolonged.

• MeSH
• časové faktory MeSH
• demografie MeSH
• koncentrační tábory MeSH
• lidé MeSH
• nukleární válka * MeSH
• populační dynamika * MeSH
• přežití * MeSH
• statistické modely MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Československo MeSH