Thermal performance curves of Paramecium caudatum: A model selection approach

Krenek, Sascha; Berendonk, Thomas U.; Petzoldt, Thomas

doi:10.1016/j.ejop.2010.12.001

Cited by 63 publications

(67 citation statements)

References 54 publications

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“…Therefore, our estimations of T min and T opt should be treated as approximations. However, this method is simple and relatively effective, while discussion on the optimal method of TPC analysis is still open (Angilletta, 2006;Gvozdik and Van Damme, 2008;Izem and Kingsolver, 2005;Krenek et al, 2011;Shi and Ge, 2010). Size differences in analyses of (i) significance of the TSR at a thermal range when size decreases (left column), and (ii) difference between size at two extreme temperatures, below lower critical temperature and above optimal temperature (right column).…”

Section: Discussionmentioning

confidence: 98%

‘Optimal thermal range’ in ectotherms: Defining criteria for tests of the temperature-size-rule

Walczyńska

Kiełbasa

Sobczyk

2016

Journal of Thermal Biology

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Section: Discussionmentioning

confidence: 98%

‘Optimal thermal range’ in ectotherms: Defining criteria for tests of the temperature-size-rule

Walczyńska

Kiełbasa

Sobczyk

2016

Journal of Thermal Biology

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“…The single-infected isolate US_Bl 15I1 was sampled from approximately 17 km away, in the 0.54-km 2 Yellowwood Lake, IN (39°11′30.2″N, 86°20′30.9″W) in 2011. Monoclonal mass cultures were established and maintained in 0.25% Cerophyl medium inoculated with Raoultella planticola (modified according to methods described by Krenek et al [25]). Total DNA was extracted for molecular characterization of host and endosymbionts; approximately 50 Paramecium cells were washed several times in sterile spring water, incubated at room temperature overnight, and washed again to minimize bacterial contaminants.…”

Section: Methodsmentioning

confidence: 99%

Disentangling the Taxonomy of Rickettsiales and Description of Two Novel Symbionts (“Candidatus Bealeia paramacronuclearis” and “Candidatus Fokinia cryptica”) Sharing the Cytoplasm of the Ciliate Protist Paramecium biaurelia

Szokoli

Castelli

Sabaneyeva³

et al. 2016

Appl Environ Microbiol

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In the past 10 years, the number of endosymbionts described within the bacterial order Rickettsiales has constantly grown. Since 2006, 18 novel Rickettsiales genera inhabiting protists, such as ciliates and amoebae, have been described. In this work, we characterize two novel bacterial endosymbionts from Paramecium collected near Bloomington, IN. Both endosymbiotic species inhabit the cytoplasm of the same host. The Gram-negative bacterium “Candidatus Bealeia paramacronuclearis” occurs in clumps and is frequently associated with the host macronucleus. With its electron-dense cytoplasm and a distinct halo surrounding the cell, it is easily distinguishable from the second smaller symbiont, “Candidatus Fokinia cryptica,” whose cytoplasm is electron lucid, lacks a halo, and is always surrounded by a symbiontophorous vacuole. For molecular characterization, the small-subunit rRNA genes were sequenced and used for taxonomic assignment as well as the design of species-specific oligonucleotide probes. Phylogenetic analyses revealed that “Candidatus Bealeia paramacronuclearis” clusters with the so-called “basal” Rickettsiales, and “Candidatus Fokinia cryptica” belongs to “Candidatus Midichloriaceae.” We obtained tree topologies showing a separation of Rickettsiales into at least two groups: one represented by the families Rickettsiaceae, Anaplasmataceae, and “Candidatus Midichloriaceae” (RAM clade), and the other represented by “basal Rickettsiales,” including “Candidatus Bealeia paramacronuclearis.” Therefore, and in accordance with recent publications, we propose to limit the order Rickettsiales to the RAM clade and to raise “basal Rickettsiales” to an independent order, Holosporales ord. nov., inside Alphaproteobacteria, which presently includes four family-level clades. Additionally, we define the family “Candidatus Hepatincolaceae” and redefine the family Holosporaceae.IMPORTANCE In this paper, we provide the characterization of two novel bacterial symbionts inhabiting the same Paramecium host (Ciliophora, Alveolata). Both symbionts belong to “traditional” Rickettsiales, one representing a new species of the genus “Candidatus Fokinia” (“Candidatus Midichloriaceae”), and the other representing a new genus of a “basal” Rickettsiales. According to newly characterized sequences and to a critical revision of recent literature, we propose a taxonomic reorganization of “traditional” Rickettsiales that we split into two orders: Rickettsiales sensu stricto and Holosporales ord. nov. This work represents a critical revision, including new records of a group of symbionts frequently occurring in protists and whose biodiversity is still largely underestimated.

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“…In order to describe the hump-shaped temperature response of growth and survival, we applied the O'Neill function (Krenek et al, 2011):…”

Section: Modelsmentioning

confidence: 99%

From population-level effects to individual response: modelling temperature dependence in Gammarus pulex

Moenickes

Schneider

Mühle

et al. 2011

Journal of Experimental Biology

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SUMMARYPopulation-level effects of global warming result from concurrent direct and indirect processes. They are typically described by physiologically structured population models (PSPMs). Therefore, inverse modelling offers a tool to identify parameters of individual physiological processes through population-level data analysis, e.g. the temperature dependence of growth from size-frequency data of a field population. Here, we make use of experiments under laboratory conditions, in mesocosms and field monitoring to determine the temperature dependence of growth and mortality of Gammarus pulex. We found an optimum temperature for growth of approximately 17°C and a related temperature coefficient, Q 10 , of 1.5°C -1 , irrespective of whether we classically fitted individual growth curves or applied inverse modelling based on PSPMs to laboratory data. From a comparison of underlying data sets we conclude that applying inverse modelling techniques to population-level data results in meaningful response parameters for physiological processes if additional temperature-driven effects, including within-population interaction, can be excluded or determined independently. If this is not the case, parameter estimates describe a cumulative response, e.g. comprising temperature-dependent resource dynamics. Finally, fluctuating temperatures in natural habitats increased the uncertainty in parameter values. Here, PSPM should be applied for virtual monitoring in order to determine a sampling scheme that comprises important dates to reduce parameter uncertainty. Supplementary material available online at

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Thermal performance curves of Paramecium caudatum: A model selection approach

Cited by 63 publications

References 54 publications

‘Optimal thermal range’ in ectotherms: Defining criteria for tests of the temperature-size-rule

‘Optimal thermal range’ in ectotherms: Defining criteria for tests of the temperature-size-rule

Disentangling the Taxonomy of Rickettsiales and Description of Two Novel Symbionts (“Candidatus Bealeia paramacronuclearis” and “Candidatus Fokinia cryptica”) Sharing the Cytoplasm of the Ciliate Protist Paramecium biaurelia

From population-level effects to individual response: modelling temperature dependence in Gammarus pulex

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