Journal of Eukaryotic Microbiology最新文献

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.

With its former circumscription, the genus Katodinium included purportedly naked species with a much larger epi- than hypocone, several of which were shown to be distantly related to the type species K. nieuportense. Most of these species have recently been transferred to other genera, several of them newly established. Among these new genera, Aduncodinium was proposed to encompass Katodinium glandula (=Gymnodinium glandula), and Speroidium was erected to encompass Katodinium fungiforme (=Gymnodinium fungiforme). However, the genus Aduncodinium was invalidly published and several morphological aspects described need to be re-evaluated. On the other hand, the inclusion in K. fungiforme of morphological and molecular characters observed in the strain known as VDH034S “Bullet,” a pfiesteriacean, needs re-evaluation because the latter shows a higher resemblance to Aduncodinium species than to K. fungiforme. The present contribution aimed to clarify the identity of the taxa involved on the basis of newly collected morphological and molecular information, and thereby avoid the nomenclatural and taxonomical uncertainties raised by previously published concepts of the genera Aduncodinium and Speroidium.

Marine protists in the eastern Bering Sea (EBS) are understudied despite being a critical component of the productive subarctic ecosystem. Climate change, and particularly the loss of sea ice, is rapidly altering this ecologically vulnerable and economically important system. In this study, the EBS protist community was characterized across recent years with drastic differences in sea ice extent. In 2019, when the extent of sea ice was anomalously low and retreat occurred early, increased fall water temperatures and surface salinities were observed, and the protist community was dominated by apicomplexan parasites. In contrast, 2017 had more typical winter sea ice conditions and in the fall, water temperatures and surface salinities were lower and protist communities were more diverse, with a larger ratio of primary producer to consumer protists compared to 2019. Surface water temperature was identified as a key predictor of apicomplexan compositional abundance and may be important in the life histories of parasites and their hosts. The interannual variability observed here indicates that the transfer of energy and biomass through the EBS ecosystem can differ drastically across years with differential sea ice influence and highlights the need to monitor protist communities and explore the impacts of protistan parasites.

Prorocentrum cf. balticum was the provisional designation assigned to strains of a small, pelagic, mixoplanktonic dinoflagellate found to produce carbon-rich mucilage-based prey capture devices, termed “mucospheres.” Here we characterize the morphology and phylogeny of the strains, describe them as Prorocentrum insidiosum sp. nov., and discuss common morphological features among the six species of the phylogenetically defined P. cordatum group. Cells of P. insidiosum sp. nov. were round to slightly ovate in lateral view, 12–16 μm long and 8–15 μm deep, and laterally compressed. Scanning electron microscopy revealed the thecal plates were densely ornamented with short spines and there were two size classes of pores irregularly distributed across both plates, and a row of two to four large round pores in apical-ventral position on the right thecal plate. The periflagellar area consisted of eight platelets, and there were two prominent wing-like apical projections in the form of a double layered curved structure on platelet 1 with additional projections on most other platelets except platelet 4. Prorocentrum insidiosum sp. nov. is distinct from all genetically represented species within the genus and possesses a unique combination of morphological features differentiating it from other protologues of small Prorocentrum species.

Unknown ellipsoid bodies, later classified as apicomplexan cysts, are prevalent in the ovaries of Japanese sea cucumbers (Apostichopus japonicus), where they can lead to lower fecundity in infected individuals and adverse effects on wild populations as well as aquaculture efforts for this endangered species. Apicomplexans are widespread and essential to marine environments, where they can affect the health and fitness of host populations. We performed genomic sequencing of recovered cysts to gain more ecological and evolutionary information on this parasite. We recovered this apicomplexan's complete nuclear ribosomal RNA (rrn) operon, the entire mitochondrial genome, and a partial apicoplast (relic chloroplast) genome. The rrn operon phylogeny revealed this parasite as being closely related to coccidian-like parasites of marine fish (ichthyocolids) and cnidarians (corallicolids), while organelle phylogenomics hint at a closer relation to the protococcidian Eleutheroschizon. Using this new phylogenetic context and previous morphological descriptions, we describe this parasite as Apostichocystis gudetama gen. nov. sp. nov. Mining available microbiomes reveal the presence of Apostichocystis spp. beyond its host range, alluding to other potential hosts or cryptic, closely related lineages. Its phylogenetic placement has important implications concerning the evolution of parasitism within Apicomplexa and the divergence of a marine-host-specific clade of coccidian-like parasites.