Tetrahymena in the Laboratory: Strain Resources, Methods for Culture, Maintenance, and Storage

Cassidy-Hanley, Donna

doi:10.1016/b978-0-12-385967-9.00008-6

Cited by 94 publications

(107 citation statements)

References 131 publications

(151 reference statements)

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…This value even exceeds search results obtained for the ciliate genus Paramecium (~5,940 hits). In contrast with nearly all other ciliates, some Tetrahymena species can be grown as pure osmotrophs in axenic cultures (Cassidy‐Hanley ), i.e. without accompanying bacteria.…”

mentioning

confidence: 99%

The Green Tetrahymena utriculariae n. sp. (Ciliophora, Oligohymenophorea) with Its Endosymbiotic Algae (Micractinium sp.), Living in Traps of a Carnivorous Aquatic Plant

Pitsch

Adamec

Dirren

et al. 2016

J Eukaryotic Microbiology

View full text Add to dashboard Cite

The genus Tetrahymena (Ciliophora, Oligohymenophorea) probably represents the best studied ciliate genus. At present, more than forty species have been described. All are colorless, i.e. they do not harbor symbiotic algae, and as aerobes they need at least microaerobic habitats. Here, we present the morphological and molecular description of the first green representative, Tetrahymena utriculariae n. sp., living in symbiosis with endosymbiotic algae identified as Micractinium sp. (Chlorophyta). The full life cycle of the ciliate species is documented, including trophonts and theronts, conjugating cells, resting cysts and dividers. This species has been discovered in an exotic habitat, namely in traps of the carnivorous aquatic plant Utricularia reflexa (originating from Okavango Delta, Botswana). Green ciliates live as commensals of the plant in this anoxic habitat. Ciliates are bacterivorous, however, symbiosis with algae is needed to satisfy cell metabolism but also to gain oxygen from symbionts. When ciliates are cultivated outside their natural habitat under aerobic conditions and fed with saturating bacterial food, they gradually become aposymbiotic. Based on phylogenetic analyses of 18S rRNA and mitochondrial cox1 genes T. utriculariae forms a sister group to Tetrahymena thermophila.

show abstract

mentioning

confidence: 99%

The Green Tetrahymena utriculariae n. sp. (Ciliophora, Oligohymenophorea) with Its Endosymbiotic Algae (Micractinium sp.), Living in Traps of a Carnivorous Aquatic Plant

Pitsch

Adamec

Dirren

et al. 2016

J Eukaryotic Microbiology

View full text Add to dashboard Cite

show abstract

“…The 20 significant protozoan species represented 15 different genera and members from the flagellate, ciliate and amoeboid groups, all of which are known predators of E. coli (Weekers et al, 1993;Fleck et al, 2000;Fey et al, 2007;Cassidy-Hanley, 2012;Yue et al, 2013). Referring to Figure 4c, it can be seen that the proportion of significant protozoan species in 13 C samples increased over time, compared with Figure 2 Absolute numbers of 16S, 18S and E. coli specific 16S rRNA in 12 C and 13 C fractions, determined by qPCR assays.…”

Section: Resultsmentioning

confidence: 90%

Stable-isotope probing and metagenomics reveal predation by protozoa drives E. coli removal in slow sand filters

et al. 2014

View full text Add to dashboard Cite

Stable-isotope probing and metagenomics were applied to study samples taken from laboratoryscale slow sand filters 0.5, 1, 2, 3 and 4 h after challenging with 13 C-labelled Escherichia coli to determine the mechanisms and organisms responsible for coliform removal. Before spiking, the filters had been continuously operated for 7 weeks using water from the River Kelvin, Glasgow as their influent source. Direct counts and quantitative PCR assays revealed a clear predator-prey response between protozoa and E. coli. The importance of top-down trophic-interactions was confirmed by metagenomic analysis, identifying several protozoan and viral species connected to E. coli attrition, with protozoan grazing responsible for the majority of the removal. In addition to top-down mechanisms, indirect mechanisms, such as algal reactive oxygen species-induced lysis, and mutualistic interactions between algae and fungi, were also associated with coliform removal. The findings significantly further our understanding of the processes and trophic interactions underpinning E. coli removal. This study provides an example for similar studies, and the opportunity to better understand, manage and enhance E. coli removal by allowing the creation of more complex trophic interaction models.

show abstract

“…We used the freshwater ciliate Tetrahymena thermophila as a model species. Due to its small body size, high population densities, and short doubling time of ∼ 4 h (Cassidy‐Hanley ; Collins ), T. thermophila is well suited for both ecological and evolutionary experiments (e.g., Fjerdingstad et al. ; Collins ; Coyne et al.…”

Section: Methodsmentioning

confidence: 99%

“…We maintained all cultures in axenic SSP medium consisting of proteose peptone, yeast extract, and glucose (Cassidy‐Hanley ; Altermatt et al. ).…”

Section: Methodsmentioning

confidence: 99%

Evolution under pH stress and high population densities leads to increased density‐dependent fitness in the protistTetrahymena thermophila

et al. 2020

View full text Add to dashboard Cite

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.

show abstract

Tetrahymena in the Laboratory: Strain Resources, Methods for Culture, Maintenance, and Storage

Cited by 94 publications

References 131 publications

The Green Tetrahymena utriculariae n. sp. (Ciliophora, Oligohymenophorea) with Its Endosymbiotic Algae (Micractinium sp.), Living in Traps of a Carnivorous Aquatic Plant

The Green Tetrahymena utriculariae n. sp. (Ciliophora, Oligohymenophorea) with Its Endosymbiotic Algae (Micractinium sp.), Living in Traps of a Carnivorous Aquatic Plant

Stable-isotope probing and metagenomics reveal predation by protozoa drives E. coli removal in slow sand filters

Evolution under pH stress and high population densities leads to increased density‐dependent fitness in the protistTetrahymena thermophila

Contact Info

Product

Resources

About