Journal of Eukaryotic Microbiology最新文献

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a major neglected disease in Latin America. The amastigote, the replicative intracellular form, is essential for infection persistence in vertebrate hosts. These forms exhibit remarkable adaptability, modulating metabolism and growth according to host cell resource availability. Lipid metabolism plays a critical role in amastigote development, with a strong dependence on host-derived lipids, particularly cholesterol. Although T. cruzi can synthesize some sterols and fatty acids, it also scavenges essential lipids from the host. Changes in host cholesterol metabolism, possibly via SREBPs, may increase intracellular cholesterol levels and promote parasite growth. However, the mechanisms of cholesterol acquisition by amastigotes remain unclear. Here, we investigated cholesterol trafficking from host cells to amastigotes using a fluorescent cholesterol analog. Through confocal and volume electron microscopy, we demonstrated cholesterol uptake by amastigotes, characterized uptake kinetics, and confirmed its importance for parasite development. We also revealed close contact between the host endoplasmic reticulum and the amastigote plasma membrane, consistent with membrane contact sites. Furthermore, we showed that amastigotes can internalize ER- and Golgi-derived host markers, suggesting a potential route for acquisition of host molecules. These findings provide new insights into lipid acquisition strategies by intracellular T. cruzi amastigotes.

Drachko, D., and V. V. Zlatogursky. 2025. “Morphology, Systematics and Life Cycle of Ozanamia fimbriatus (Haptista: Centroplasthelida), With Notes on Evolution of Organic Skeleton in Centrohelids.” Journal of Eukaryotic Microbiology 72, no. 4: e70022. https://doi.org/10.1111/jeu.70022.

In the originally published article, the funding information given at the beginning of the article was incorrect. The correct funding information is given below. This has been updated in the online version of the article.

Incorrect

Funding: This work was supported by Russian Academy of Sciences, 24-74-10031.

Correct

Funding: This work was supported by the Russian Science Foundation, 24-74-10031.

We apologize for this error.

Tintinnid ciliates are distinguished by their loricae (shells), the key synapomorphy of these mainly marine planktonic protists. They can divide daily, with a considerable portion of biomass stored in the loricae. During each division, lorica-forming material (LFM) is produced and afterwards used by the proter (anterior division product) to construct a new lorica, while the opisthe (posterior division product) retains the parental one. Many aspects of lorica formation remain unclear, and no study describes the entire process from material maturation via secretion to assembly. Here, we present the first thorough investigation at cellular and sub-cellular levels, employing light microscopy on dividers and postdividers, as well as transmission electron microscopy on primarily cryofixed specimens from a Schmidingerella culture. Our study reconstructs LFM maturation, identifying two main developmental stages: the morula-shaped precursor granules and the mature granules. The latter cluster in the proter's ventral portion with a peripheral longitudinal strip of small granules embedded in large ones. Ultrastructurally and chemically, the mature granules of both size classes are identical. Through detailed live observations, we followed and documented, for the first time, the process of cell division, the behavior of the proter, the release of LFM granules, and features of lorica formation.

The nuclear genome is essential for encoding most of the genes required for cellular processes, but its size alone can alter the characteristics of cells and organisms. Yet, genome size variation and its ecological and evolutionary impacts, particularly in microorganisms, are not well understood. We used flow cytometry to estimate genome size and GC content in 53 evolutionary lineages of the microalgal genus Synura (Chrysophyceae, Stramenopiles). Genome size evolution was reconstructed in a phylogenetic framework using molecular markers. A set of genomic, morphological, and ecogeographic variables characterizing Synura lineages was evaluated and tested as predictors of genome size variation in phylogeny-corrected statistical models. Both genome size and GC content varied widely in Synura, ranging from 0.19 to 3.70 pg of DNA and 34.0% to 49.3%, respectively. Genome size variation was mainly associated with cell size, less with silica scale size, and not with scale ultrastructure. Higher soil nitrogen, higher latitudes, and lower temperatures correlated with larger genomes. Genome size evolution in Synura shows potential dynamism, with increases confined to short terminal branches, indicating lower macroevolutionary stability. Lineages with larger genomes exhibited a narrower range of suitable ecological conditions, possibly due to selection acting deleteriously against larger genomes (and cells).

EXPRESSION OF CONCERN: L. Giordana, B. S. Mantilla, M. Santana, A. M. Silber, and C. Nowicki, “ Cystathionine γ-lyase, an Enzyme Related to the Reverse Transsulfuration Pathway, is Functional in Leishmania spp.,” Journal of Eukaryotic Microbiology 61, no. 2 (2014): 204–213, https://doi.org/10.1111/jeu.12100.

This Expression of Concern is for the above article, published online on 11 January 2014 in Wiley Online Library (wileyonlinelibrary.com), and has been issued by agreement between the journal Editor-in-Chief, Joel B. Dacks; The International Society of Protistologists; and Wiley Periodicals LLC. The Expression of Concern has been agreed due to concerns raised by third parties. A duplication of the Western Blot bands depicting “CS_P” and “CGL_P” has been identified in Figure 5B. The authors have acknowledged an unintentional duplication of one of the western blot images corresponding to CS_P or CGL_P during figure preparation, rather than duplication of the individual band. The authors declare that none of the western blots in the figure were altered in any form. However, due to the time elapsed since publication, the original data could not be recovered to rectify the mistake. As the conclusions are not affected by the issue detected, the journal has decided to issue an Expression of Concern to inform and alert the readers.

The Prorocentrales are a diverse group of dinophytes found in a wide range of marine environments. However, species delimitation in the genus Prorocentrum still remains a challenge, especially for nanoscale species where morphological and molecular information is often incomplete. Prorocentrum nux is an example where information is sparse and efforts are needed. In this study, we present a detailed description of the morphological features and molecular information for a Northwest Atlantic strain (AGSB-0131). Using Scanning Electron Microscopy, additional morphological features from the original description were highlighted, including the periflagellar area configuration (nine vs. seven platelets) and pattern dissimilarities for the large and marginal pores. In addition to the revised description, the 18S rRNA gene, partial 28S rRNA gene, mitochondrial cox1 and cob genes were generated from strain AGSB-0131, revealing some ambiguity in the existing data available for P. nux. An important genetic divergence between the only 18S rRNA sequence currently available for P. nux (strain RCC303) and AGSB-0131 was highlighted, suggesting the importance of using the same strain to retrieve morphological and molecular information for nanodinoflagellates. Adding genetic markers for the correct identification of P. nux will enhance the ability to access its prevalence in the marine environment.

The Apicomplexa are obligate unicellular parasites found in terrestrial and aquatic environments. Nematopsis are found infecting marine invertebrates in a life cycle involving mollusks and crustaceans. In the present study, mantle and muscle tissues from nerite gastropods were microscopically examined for Nematopsis using wet mounts and histology. Oocysts contained one single sporozoite surrounded by an ellipsoidal wall and were surrounded by a parasitophorous vacuole within a host phagocyte. Length and width of fresh oocysts were measured and compared between host species. DNA was extracted from infected tissue, and regions of the rRNA gene were amplified using novel primers. Nematopsis-infected tissues from scallops from Argentina and Scotland were used as controls. The sizes of oocysts observed in nerite hosts from Saint Kitts were not significantly different. DNA sequences of Nematopsis isolated from nerite hosts in this study were identical and phylogenetically related to sequences obtained from scallops. Bayesian and maximum likelihood phylogenetic analyses robustly place the Nematopsis DNA sequences from this study with Nematopsis from scallops in Florida and members of the family Porosporidae. We conclude that marine Nematopsis will group within this clade or within the Porosporidae. We have provided specific oligonucleotide primers to assist with the molecular study of the Porosporidae.