Journal of Eukaryotic Microbiology最新文献

The International Symposium on Ciliate Biology (ISCB 2025) was held at Acharya Narendra Dev College, University of Delhi. The symposium brought together leading experts from around the world. Preceded by hands-on workshops in taxonomy and genomics, the symposium offered a dynamic platform for knowledge exchange, featuring plenary lectures, invited talks, oral presentations, and posters on topics spanning biodiversity, taxonomy, cell biology, model systems, health, toxicology, and science communication. Sessions highlighted ciliates' ecological significance—from climate change monitoring to their roles as bioindicators and agents of environmental restoration. Cutting-edge research showcased molecular, cellular, and integrative approaches, including phylogenomic analyses, innovative uses of ciliates in pollution detection, vector control, and explored practical applications of ciliates in health and agriculture. The event drew approximately 300 participants, with strong international representation, fostering new collaborations and inspiring future research. Recommendations from the symposia advocate for enhanced interdisciplinary efforts, expanded molecular tools, frugal science innovations, and greater public science communication. The ISCB 2025 concluded with a cultural program and a General Body Meeting of the Indian Society of Ciliate Biology (ISoCB) outlining strategic directions for ISoCB, including global membership and triennial symposia. The event underlined the pivotal role of ciliates in biological research, environmental stewardship, and education.

Phosphorus (P) is a chemical element essential for life that can drive dynamics of microorganisms in marine environments. Nutrient acquisition by parasitic organisms is mainly done through infection. In the case of micro-parasites, how host diet limitations affect parasite stoichiometry and parasite–host interaction has not been thoroughly studied yet. This study focused on the free-living stage of Amoebophrya ceratii, a micro-parasite (Syndiniales, Dinoflagellates) of marine dinoflagellates. It aims to examine how host P limitation prior to infection affects parasite stoichiometry and infection cycle. To this end, Scrippsiella acuminata was used as a host and cultivated under P-replete or P-limiting conditions. Infection and parasite production were monitored, and elemental quotas and stoichiometry of the freshly produced dinospores were determined. In P-replete conditions, elemental quotas and ratios of the parasites were similar to their host, showing a strong need for P. While the host's stoichiometry was greatly impacted by P limitation, parasites were able to maintain stoichiometric homeostasis and elemental cell quotas. Finally, host P limitation mainly affected the dinospore production, exhibiting a trade-off between dinospores quotas, stoichiometric homeostasis, and production. These findings have implications for host–parasite interactions and biogeochemical cycling in coastal waters.

Myxomycetes are valuable models for studying interactions between single-celled eukaryotes and bacteria; however, little is known about their microbiota or optimal DNA extraction methods. We analyzed the bacterial community of Claustria didermoides plasmodia using commercial and noncommercial DNA extraction methods. A total of 218 amplicon sequence variants (ASVs) were identified, dominated by Pseudomonadota (78%), Bacillota (10%), and Actinomycetota (9%). Achromobacter denitrificans was the most abundant species, with 3–7 codominant ASVs, including opportunistic pathogens. The commercial kit captured higher diversity, while the noncommercial method favored Gram-negatives and preserved DNA integrity longer when phenol was added.

Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) play essential roles in eukaryotic cell biology, yet their evolutionary diversity across alveolates remains poorly understood. Here, we conducted a comparative genomic analysis of GPI biosynthetic pathways and GPI-AP repertoires across representative species of Ciliophora, Apicomplexa, and Dinoflagellata. Our findings reveal lineage-specific patterns of gene loss, expansion, and functional divergence, with ciliates exhibiting reduced canonical enzyme sets but expanded trafficking components. Using a benchmarked pipeline of GPI-AP predictors combined with signal peptide detection, we identified candidate GPI-anchored proteins and performed functional annotation to determine enriched Gene Ontology terms. To complement the bioinformatic analyses, we expressed the apicomplexan GPI-anchored antigen GPI4 from Babesia bovis in Tetrahymena thermophila. This approach extends previous efforts that used Tetrahymena as a heterologous expression system for parasite surface antigens. The recombinant protein localized to ciliary membranes and showed features consistent with proper processing. This study highlights the evolutionary plasticity of GPI systems in alveolates and reinforces the utility of Tetrahymena as a eukaryotic platform for the production and analysis of GPI-anchored proteins with potential diagnostic or immunoprophylactic applications.

Avian coccidiosis, an intestinal parasitic disease caused by Eimeria spp., remains one of the most economically significant diseases in poultry. Although anticoccidial drugs have been effective in controlling coccidiosis, the emergence of drug resistance in Eimeria poses a persistent challenge to disease management. Our previous study revealed differential expression of superoxide dismutase (EtSOD) between drug-sensitive (DS) and drug-resistant Eimeria tenella strains. In this study, qPCR and western blot analyses demonstrated that EtSOD expression was significantly upregulated in diclazuril-resistant (DZR) and maduramicin-resistant (MRR) strains compared to the DS strain, with a progressive increase corresponding to higher drug concentrations. Enzyme activity assays further confirmed that SOD activity was elevated in both resistant strains. Additionally, qPCR results indicated higher EtSOD mRNA levels in second-generation merozoites and unsporulated oocysts than in sporulated oocysts and sporozoites. Indirect immunofluorescence revealed that fluorescence intensity increased during parasite development within host cells. Notably, EtSOD was predominantly localized on the surface of sporozoites and merozoites, as well as on the parasitophorous vacuole membrane (PVM) post-invasion of DF-1 cells, suggesting its potential role in host–parasite interactions and immune evasion. Collectively, these findings imply that EtSOD may contribute to drug resistance and facilitate parasite growth and development within host cells.