Volume 63, Special Issue

Special Issues

Publication date: 2025

Description

Special topic issue: International Society of Testate Amoebae

Licence: CC BY

Editorial team

Editor-in-Chief Krzysztof Wiąckowski

Guest editor Edward A. D. Mitchell

Issue content

A brief history of testate amoebae research and introducing the International Society for Testate Amoeba Research (ISTAR)

Edward A. D. Mitchell

Acta Protozoologica, Volume 63, Special Issue, Special Issues, pp. 1-14

https://doi.org/10.4467/16890027AP.25.003.21792

Research on testate amoebae goes back to the early 19th century, more precisely the year 1815 when Leclerc (or Le Clerc) described the genus Difflugia , which he presented as a “new type of amorphous polyp” (Leclerc, 1815). Since then the pace of publication was uneven but some very significant early works such as the seminal works of Leidy, Penard, and Cash, Hopkinson and Wailes paved the way to future research (Penard, 1890, Penard, 1902, Penard, 1911, Leidy, 1879, Cash et al., 1905-1921). These early studies focused on describing the diversity of testate amoebae but also included discussions (or speculations) about their geographical distribution and ecology. The lives and scientific careers of Leidy and Penard were nicely described by Corliss who had the privilege of meeting Penard towards the end of his long life (Corliss, 2001).

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In search of Testate Amoebae in the Polar Regions: thoughts on a life time passion

Louis Beyens

Acta Protozoologica, Volume 63, Special Issue, Special Issues, pp. 15-21

https://doi.org/10.4467/16890027AP.25.003.21210

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A new golden era for research on testate amoebae: Looking back at 30 years of research

Edward A. D. Mitchell

Acta Protozoologica, Volume 63, Special Issue, Special Issues, pp. 23-33

https://doi.org/10.4467/16890027AP.25.004.21793

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Cell rupture in Arcellinida through the lens of evolution

Kenneth Dumack

Acta Protozoologica, Volume 63, Special Issue, Special Issues, pp. 35-39

https://doi.org/10.4467/16890027AP.25.004.21211

The majority of predatory protists are size-limited. Arcellinida (Amoebozoa) exhibit the remarkable ability to prey upon larger rganisms. Here, we examine the co-evolution of their robust shells and predatory behavior. Tracing back to the emergence of eukaryotes, we explore how early amoebozoan predators adapted their cytoskeletons to master phagocytosis. We speculate that the diversity of shell morphology as we see it in extant Arcellinida might be a direct result to their adaptation to prey on large organisms.

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Towards testate amoebae genomics and beyond, a wish list…

Anush Kosakyan

Acta Protozoologica, Volume 63, Special Issue, Special Issues, pp. 41-47

https://doi.org/10.4467/16890027AP.25.005.21212

Despite of the rapid advancements in genomic tools over the past decade, genomic data remains limited for many protists, with some taxonomic groups lacking it entirely. One such group is testate amoebae, a group of shelled amoeboid protists known to have a long fossil record. Indeed, for some of them (i.e., arcellinid testate amoebae) the evolutionary roots trace back approximately 730 million years. Beyond their fascinating evolutionary history, these organisms are highly valued for their diverse applications across various research fields, including paleoecology, environmental monitoring, ecotoxicology, microbial community ecology, endosymbiont studies, and more. Consequently, their genomic data harbors significant potential for yielding crucial insights within the contexts of evolution, ecology, and climate change, while also offering opportunities for exploration from both biotechnological and functional perspectives. This short communication gives an overview of possible research directions for testate amoebae based on molecular data and outlining innovative techniques that have the potential to elevate testate amoebae research to a new next level.

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Survival in a changing world: The role of transcriptomics and the urgent need for genomes to understand Arcellinida’s adaptive capabilities

Giulia M. Ribeiro, Daniel J. G. Lahr

Acta Protozoologica, Volume 63, Special Issue, Special Issues, pp. 49-57

https://doi.org/10.4467/16890027AP.25.006.21213

Understanding the physiological and genetic diversity of single-cell eukaryotes remains a big challenge for scientists. Single-cell omics technologies have revolutionized our possibilities for many previously uncharacterized groups. Despite the great advancement, there is still a substantial gap in our genomic knowledge about eukaryotes, with less than 1% of species sequenced. This knowledge gap is even more pronounced in some microbial eukaryote groups such as Arcellinids. Arcellinida is a group of bioindicator protists that inhabit mostly freshwater and soil environments. Currently, we don’t have any genome available for the Arcellinida group, undermining our capacity to understand their biology, metabolic capacities, and resistance mechanisms that makes them useful as bioindicators. Using transcriptomic data only, we made great progress in this group by elucidating, for example, their systematics, sex, and metabolism. This manuscript highlights the potential of Arcellinida as a model for genomic studies, particularly the Arcella uspiensis species. Through comparative analysis, we demonstrate that despite its importance, transcriptomics hinders some limitations that need to be acknowledged. Finally, considering that we have much basic biology knowledge and protocols for Arcella uspiensis, we propose sequencing the genome of this species as a way to unlock further potential insights into ecology, evolution, and function of Arcellinida. This manuscript emphasizes the importance of exploring genomics as a way to understand the ecology and evolution of microbial eukaryotic groups.

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Słowa kluczowe: amoebae, Amoebozoa, Actin, cytoskeleton, phagocytosis, testate amoebae, single cell genomics, future perspectives, molecular techniques, WGA, Single-cell omics, Microbial eukaryotes, Arcellinida, Arcella uspiensis, Comparative analysis