Comprehensive genome annotation of the model ciliate Tetrahymena thermophila by in-depth epigenetic and transcriptomic profiling.

The ciliate Tetrahymena thermophila is a well-established unicellular model eukaryote, contributing significantly to foundational biological discoveries. Despite its acknowledged importance, current studies on Tetrahymena biology face challenges due to gene annotation inaccuracy, particularly the notable absence of untranslated regions (UTRs). To comprehensively annotate the Tetrahymena macronuclear genome, we collected extensive transcriptomic data spanning various cell stages.

New insights and investigation: Morphomolecular notes on the infraciliature, taxonomy, and systematics of pleurostomatid ciliates (Protozoa, Ciliophora), with establishment of a new suborder, two new genera, and three new species.

Pleurostomatid ciliates, as a highly diverse and widely distributed unicellular eukaryote group, play a crucial role in the cycling of nutrients and energy in microbial food webs. However, research on pleurostomatids remains insufficient, resulting in a paucity of molecular information and substantial gaps in knowledge of their phylogenetic relationships. In recent years, we investigated pleurostomatid diversity in various Chinese habitats, including their systematic relationships and taxonomic circumscriptions, which were comprehensively analyzed using an integrative morphomolecular approach.

Exploring the biogeography, morphology, and phylogeny of the condylostomatid ciliates (Alveolata, Ciliophora, Heterotrichea), with establishment of four new species and a revision including redescriptions of five species found in China.

Unlabelled: Species of the ciliate class Heterotrichea Stein, 1859 are a cosmopolitan group of unicellular eukaryotic microorganisms, many of which have been widely used as models in various fields of research such as regenerative biology, functional ecology, environmental toxicology, and symbiotic behavior. However, species identification in the heterotrich family Condylostomatidae, especially the most species-rich and type genus Bory de Saint-Vincent, 1824, remains challenging due to incomplete original descriptions, few reliable distinguishing characters, and overlapping features between different species. This study presents an updated revision of and its related genus da Silva Neto, 1994 based on descriptions of five species, including nine populations collected from China, using both morphological and molecular methods.

Multi-gene-based investigation on the molecular phylogeny of the hypotrichous family Strongylidiidae (Protista, Ciliophora), with notes on the ontogeny of a new genus and new species.

Unlabelled: Ciliates in the subclass Hypotrichia have long been difficult to classify as they are one of the most polymorphic and highly differentiated groups, leading to their systematics remaining unresolved. Phylogenetic relationships within the hypotrich family Strongylidiidae have been ambiguous due to discordance between the morphological and genetic data. In this study, a new strongylidiid genus is established, mainly based on the novel mode of origin of the ventral cirral rows: left ventral cirral row (LVR) originates from frontal-ventral-transverse cirral anlagen (FVTA) III (anterior portion), IV (middle portion), and V (rear portion); right ventral cirral row comes from the entire FVTA VI.

Decryption of the survival "black box": gene family expansion promotes the encystment in ciliated protists.

Background: Encystment is an important survival strategy extensively employed by microbial organisms to survive unfavorable conditions. Single-celled ciliated protists (ciliates) are popular model eukaryotes for studying encystment, whereby these cells degenerate their ciliary structures and develop cyst walls, then reverse the process under more favorable conditions. However, to date, the evolutionary basis and mechanism for encystment in ciliates is largely unknown.