Find research datasets worth reusing

opencc-zeroDec 2019View details →

Evolution under pH stress and high population densities leads to increased density-dependent fitness in the protist Tetrahymena thermophila

Abiotic stress is a major force of selection that organisms are constantly facing. While the evolutionary effects of various stressors have been broadly studied, it is only more recently that the relevance of interactions between evolution and underlying ecological conditions, that is, eco-evolutionary feedbacks, have been highlighted. Here, we experimentally investigated how populations adapt to pH-stress under high population densities. Using the protist species Tetrahymena thermophila, we studied how four different genotypes evolved in response to stressfully low pH conditions and high population densities. We found that genotypes underwent evolutionary changes, some shifting up and others shifting down their intrinsic rates of increase (r0). Overall, evolution at low pH led to the convergence of r0 and intraspecific competitive ability (α) across the four genotypes. Given the strong correlation between r0 and α, we argue that this convergence was a consequence of selection for increased density-dependent fitness at low pH under the experienced high density conditions. Increased density-dependent fitness was either attained through increase in r0 , or decrease of α, depending on the genetic background. In conclusion, we show that demography can influence the direction of evolution under abiotic stress.

Fig. 9. T. thermophila cells immunostained with monoclonal anti-cdc14A in Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

Fig. 9. T. thermophila cells immunostained with monoclonal anti-cdc14A antibody. Cs and nCS – apical couplets of basal bodies for proter and opisthe, respectively; Ma – macronucleus. Other explanations as in Figs 1 and 8. Bar: 10 µm, bar in D for B–D.

Fig. 7. T. thermophila cells immunostained with the antiserum against component B in Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

Fig. 7. T. thermophila cells immunostained with the antiserum against component B of epiplasm. DF – staining around the deep fibers. Other explanations as in Fig. 1. Bar: 10 µm.

Fig. 2 in Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

Fig. 2. Localization of nuclei in control and roscovitine treated T. tetrmophila. The cells were immunostained with the anti-centrin 20H5 antibody and stained with DAPI. A and B – control cells in the VI stage of morphogenesis, and early cytokinesis, respectively; C and D – roscovitine treated cells (4 h) in the VI stage of morphogenesis and in cytokinesis respectively. Arrows – micronuclei (in the C micronucleus in opisthe is out of focus). Bar: 10 µm.

Fig. 4. Postdivider cells after 5.5 h in Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

Fig. 4. Postdivider cells after 5.5 h of roscovitine treatment. Cells were immunostained with anti-centrin 20H5 antibody. A and A' – ventral and dorsal views of the same proter cell with remnants of the OA2; B–C opisthe cells, B – opisthe with ARF on dorsal side, C – opisthe with remnants of oral structures; D and D' – ventral and dorsal views of the same cell; E and E' – ventral and dorsal views of the same opisthe during pinching off the OA. Other explanations as in Fig. 1. Bar: 10 µm for A–E'.

Fig. 5 in Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

Fig. 5. Mean cell sizes, positions of OA1, OA2 and fission zone in control and in roscovitine treated cells. Upper panel: early and late control dividers, lower panel: early dividers after 3.5 h roscovitine treatment, late dividers after 3.5 and 5.5 h roscovitine treatment. The shape of cells is represented by elipses. Solid horizontal lines – cells "equator", dotted horizontal lines – positions of the fission furrow. All sizes and distances were drawn to the same scale. Bar: 10 µm. The measurements represent means of at least 10 specimens for each cell sample.

Fig. 6 in Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

Fig. 6. Correlation of length of proters and shift of the fission zone in relation to OA2 induced by roscovitine in late dividers. The shift of the fission zone was measured as a difference between length of the proters and distance from cell apex to the anterior end of the OA2 (ordinate). Each point in this diagram represent individual cell. Open symbols – untreated cells, close symbols – cells treated with roscovitine for 3.5 and 5.5 h (pooled).

Fig. 10 in Effects of Roscovitine on Schedule of Divisional Morphogenesis, Basal Bodies Proliferation and Cell Divisions in Tetrahymena thermophila

Fig. 10. Western blot of T. thermophila fractions with monoclonal antibody anti-cdc14A. H – homogenate, S – supernatant, C – cortical fraction (pellet).

opencc-zeroOct 2021View details →

Data from: Selection on growth rate and local adaptation drive genomic adaptation during experimental range expansions in the protist Tetrahymena thermophila

1. Populations that expand their range can undergo rapid evolutionary adaptation of life-history traits, dispersal behaviour, and adaptation to the local environment. Such adaptation may be aided or hindered by sexual reproduction, depending on the context. 2. However, few empirical and experimental studies have investigated the genetic basis of adaptive evolution during range expansions. Even less attention has been given to the question how sexual reproduction may modulate such adaptive evolution during range expansions. 3. We here studied genomic adaptation during experimental range expansions of the protist Tetrahymena thermophilain landscapes with a uniform environment or a pH-gradient. Specifically, we investigated two aspects of genomic adaptation during range expansion. Firstly, we investigated adaptive genetic change in terms of the underlying numbers of allele frequency changes from standing genetic variation and de novo variants. We focused on how sexual reproduction may alter this adaptive genetic change. Secondly, we identified genes subject to selection caused by the expanding range itself, and directional selection due to the presence or absence of the pH-gradient. We focused this analysis on alleles with large frequency changes that occurred in parallel in more than one population to identify the most likely candidate targets of selection. 4. We found that sexual reproduction altered adaptive genetic change both in terms of de novo variants and standing genetic variation. However, sexual reproduction affected allele frequency changes in standing genetic variation only in the absence of long-distance gene flow. Adaptation to the range expansion affected genes involved in cell divisions and DNA repair, whereas adaptation to the pH-gradient additionally affected genes involved in ion balance, and oxidoreductase reactions. These genetic changes may result from selection on growth and adaptation to low pH. 5. In the absence of gene flow, sexual reproduction may have aided genetic adaptation. Gene flow may have swamped expanding populations with maladapted alleles, thus reducing the extent of evolutionary adaptation during range expansion. Sexual reproduction also altered the genetic basis of adaptation in our evolving populations via de novo variants, possibly by purging deleterious mutations or by revealing fitness benefits of rare genetic variants.

publicDec 2019View details →

Evolution under pH stress and high population densities leads to increased density-dependent fitness in the protist Tetrahymena thermophila

Open the record for dataset details and reuse information.

publicOct 2021View details →

Data from: Selection on growth rate and local adaptation drive genomic adaptation during experimental range expansions in the protist Tetrahymena thermophila

Open the record for dataset details and reuse information.

opencc-zeroJun 2021View details →

Amitosis confers benefits of sex in the absence of sex to Tetrahymena

Sex appears to be the most successful reproductive strategy in eukaryotes despite its many costs. While a complete explanation for sex's success remains elusive, several evolutionary benefits of sex have been identified. It is predicted that, by forgoing these benefits, asexual lineages are evolutionary dead-ends. Consistent with this prediction, many asexual lineages show signs of accelerated accumulation of deleterious mutations compared to their sexual relatives. Despite these low expectations, some asexual eukaryotic lineages appear to be successful, including the ciliate Tetrahymena. Here, we show that the mechanism of somatic nuclear division in Tetrahymena, known as amitosis, provides benefits similar to sex, allowing for the long-term success of asexual lineages. We found that, when compared to mitosis, amitosis with chromosome copy number control reduces mutation load deterministically, slows the accumulation of deleterious mutations under genetic drift, and accelerates adaptation. These benefits arise because, like sex, amitosis can generate substantial genetic variation in fitness among (asexual) progeny. Our results indicate that the ability of Tetrahymena to persist in the absence of sex may depend on non-sexual genetic mechanisms conferring benefits typically provided by sex, as has been found in other asexual lineages.

opencc-zeroOct 2023View details →

The phenotypic and fitness response to the combination of copper and thermal stressors strongly varies within the ciliate species, Tetrahymena thermophila

Copper pollution can alter biological and trophic functions. Organisms can set up different tolerance strategies, including accumulation mechanisms (intracellular vacuoles, external chelation, etc.) to maintain themselves in copper-polluted environments. Accumulation mechanisms can influence the expression of other phenotypic traits, allowing organisms to improve their fitness. Whether copper effects on accumulation strategies interact with other environmental stressors such as temperature and how this may differ within species are still unsolved questions. Here, we tested experimentally whether the combined effect of copper and temperature modulates traits linked to fitness, morphology, movement and accumulation in six strains of the ciliate Tetrahymena thermophila. We also explored whether copper accumulation might modulate environmental copper concentration effects on phenotypic and fitness traits. Results showed high intraspecific variability in the phenotypic and fitness response to copper, with interactive effects between temperature and copper. In addition, they suggested an attenuation effect of copper accumulation on the sensitivity of traits to copper, but with great variation between strains, temperature and copper concentration. Diversity of responses among strains and their thermal dependencies pleads for the integration of intraspecific variability and multiple stressors approaches in ecotoxicological studies, thus improving the reliability of assessments of the effects of pollutants on biodiversity.

zenodo36/100

Microchamber slide design for cell confinement during imaging- Tetrahymena rostrata timelapse data

We performed Imaging on a Nikon Ti2-E & Yokogawa CSU W1-SoRa microscope. The microscope was equipped with an ORCA-Fusion BT digital C-MOS camera. We used a 10× 0.45 Plan Apo Air  or a  Plan Apo λD 100x OIL OFN25 DIC N2 objective for differential interference contrast (DIC) imaging. More microscopy information is detailed in the metadata file associated with each .nd2 file. Tetrahymena rostrata was provided by Andrzej Kaczanowski, who isolated the cells from the small snail Cohlicopa lubrica near Warsaw. The cells were cultured in medium consisting 0.5% yeast extract and 0.5% of proteose peptone supplemented with 250 ug/ml streptomycin sulphate and 250 ug/ml penicillin G to maintain sterility.

opencc-by-4.0Nov 2023View details →

opencc-zeroApr 2024View details →

Mass spectrometry of axonemes from Tetrahymena thermophila CU428 and acetylation mutants

Acetylation of α-tubulin at the lysine 40 residue (αK40) by the ATAT1/MEC-17 acetyltransferase influences the properties of microtubules and is a widespread phenomenon in eukaryotic cells. Previous research indicates that microtubules that undergo acetylation at αK40 are more stable and resilient to damage. Notably, αK40 acetylation represents the sole identified post-translational modification site within the microtubule lumen, suggesting its role in regulating the lateral interactions among protofilaments within the microtubule structure. This investigation focuses on evaluating the impact of tubulin acetylation on doublet microtubules present in the cilia of Tetrahymena thermophila, employing mass spectrometry analysis. Cilia samples derived from Tetrahymena wild type, acetylation mutants (K40R and MEC17-Knockout), and non-acetylation mutants (RIB72B-Knockout and RIB72AB-Knockout) underwent comparative mass spectrometry analysis. The results from mass spectrometry revealed a correlation between αK40 acetylation and phosphorylation within the ciliary structures.

zenodo36/100

Seasonality of cyanobacteria and eukaryotes in Lake Geneva and the impacts of cyanotoxins on growth of the model ciliate Tetrahymena pyriformis

Toxic cyanobacteria are likely to be favored by global warming and other human impacts, posing significant threats to aquatic ecosystems. While cyanobacterial blooms in eutrophic lakes are widely investigated, the dynamics of cyanobacteria and the effects of their toxins and bioactive metabolites on the plankton communities in mesotrophic and oligotrophic lakes are less well understood.  Here we investigated seasonal dynamics of cyanobacteria, eukaryotic algae and cyanotoxins in oligo-mesotrophic Lake Geneva—the largest and deepest lake in western Europe. High-throughput sequencing of the 16S rRNA genes in 143 samples along a water column revealed that Lake Geneva hosts diverse, co-dominant cyanobacterial genera, including Planktothrix, Cyanobium, Pseudanabaena, and Aphanizomenon. The abundance of the mcyA gene marker for microcystin production was highly correlated with total cyanobacteria abundance, obtained from qPCR of the 16S rRNA genes. Targeted LC-HRMS/MS analysis demonstrated peak concentrations of cyanotoxins in September and December 2021 at the deep chlorophyll-a maximum layer, reaching up to 1474 ng/l for anabaenopeptins and 144 ng/l for microcystins. The toxin peaks did not correlate with the abundance or variations in the cyanobacteria or eukaryote community, but they were correlated in time with seasonal lows in the abundances of ciliates (18S rRNA analysis). Laboratory exposure tests demonstrated that growth of the model ciliate Tetrahymena pyriformis was inhibited by Microcystin-RR and Anabaenopeptin A at environmentally relevant concentrations in the ng/l-range, in natural lake water, synthetic freshwater, and growth media spiked with the cyanotoxins. Our findings suggest that even low concentrations (in the ng/l-range) of microcystins and anabaenopeptins, reduce growth of ciliates such as T. pyriformis and can be expected to have wider impacts on the eukaryote communities.

opencc-by-4.0Dec 2024View details →

zenodo36/100

MAC genome assembly and gene prediction of Tetrahymena thermophila SB210

Corrected genome assembly and gene prediction of the MAC genome of T. thermophila SB210. These data were generated and analysed in the manuscript "Single-nucleotide polymorphism landscape of the macronuclear genome of Tetrahymena thermophila". Please see the Material & methods and Supplementary data files of this manuscript for more details about these files.

opencc-by-4.0May 2023View details →

publicApr 2024View details →

Mass spectrometry of axonemes from Tetrahymena thermophila CU428 and acetylation mutants

Open the record for dataset details and reuse information.