Kiran J. More , Harpreet Kaur , Alastair G.B. Simpson , Frederick W. Spiegel , Joel B. Dacks
{"title":"Contractile vacuoles: a rapidly expanding (and occasionally diminishing?) understanding","authors":"Kiran J. More , Harpreet Kaur , Alastair G.B. Simpson , Frederick W. Spiegel , Joel B. Dacks","doi":"10.1016/j.ejop.2024.126078","DOIUrl":"10.1016/j.ejop.2024.126078","url":null,"abstract":"<div><p>Osmoregulation is the homeostatic mechanism essential for the survival of organisms in hypoosmotic and hyperosmotic conditions. In freshwater or soil dwelling protists this is frequently achieved through the action of an osmoregulatory organelle, the contractile vacuole. This endomembrane organelle responds to the osmotic challenges and compensates by collecting and expelling the excess water to maintain the cellular osmolarity. As compared with other endomembrane organelles, this organelle is underappreciated and under-studied. Here we review the reported presence or absence of contractile vacuoles across eukaryotic diversity, as well as the observed variability in the structure, function, and molecular machinery of this organelle. Our findings highlight the challenges and opportunities for constructing cellular and evolutionary models for this intriguing organelle.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126078"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000282/pdfft?md5=a737d325ac61ad6612c36ea14636eba7&pid=1-s2.0-S0932473924000282-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140404661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eric Odle , Siratee Riewluang , Kentaro Ageishi , Hiroshi Kajihara , Kevin C. Wakeman
{"title":"Pacific marine gregarines (Apicomplexa) shed light on biogeographic speciation patterns and novel diversity among early apicomplexans","authors":"Eric Odle , Siratee Riewluang , Kentaro Ageishi , Hiroshi Kajihara , Kevin C. Wakeman","doi":"10.1016/j.ejop.2024.126080","DOIUrl":"10.1016/j.ejop.2024.126080","url":null,"abstract":"<div><p>Gregarines are the most biodiverse group of apicomplexan parasites. This group specializes on invertebrate hosts (e.g., ascidians, crustaceans, and polychaetes). Marine gregarines are of particular interest because they are considered to be the earliest evolving apicomplexan lineage, having subsequently speciated (and radiated) through virtually all existing animal groups. Still, mechanisms governing the broad (global) distribution and speciation patterns of apicomplexans are not well understood. The present study examines Pacific lecudinids, one of the most species-rich and diverse groups of marine gregarines. Here, marine polychaetes were collected from intertidal zones. Single trophozoite cells were isolated for light and electron microscopy, as well as molecular phylogenetic analyses using the partial 18S rRNA gene. The cytochrome <em>c</em> oxidase subunit 1 gene was used to confirm morphology-based host identification. This study introduces <em>Undularius glycerae</em> n. gen., n. sp. and <em>Lecudina kitase</em> n. sp. (Hokkaido, Japan), as well as <em>Difficilina fasoliformis</em> n. sp. (California, USA). Occurrences of <em>Lecudina</em> cf. <em>longissima</em> and <em>Lecudina</em> cf. <em>tuzetae</em> (California, USA) are also reported. Phylogenetic analysis revealed a close relationship between <em>L</em>. <em>pellucida</em>, <em>L</em>. <em>tuzetae</em>, and <em>L</em>. <em>kitase</em> n. sp. Additionally, clustering among North Atlantic and Pacific <em>L</em>. <em>tuzetae</em> formed a species complex, likely influenced by biogeography.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126080"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140404776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tristan C. Henderson, Lucia Garcia-Gimeno, Charles E. Beasley Jr., Nicholas W. Fry, Jayden Bess, Matthew W. Brown
{"title":"High above the rest: standing behaviors in the amoebae of Sappinia and Thecamoeba","authors":"Tristan C. Henderson, Lucia Garcia-Gimeno, Charles E. Beasley Jr., Nicholas W. Fry, Jayden Bess, Matthew W. Brown","doi":"10.1016/j.ejop.2024.126082","DOIUrl":"https://doi.org/10.1016/j.ejop.2024.126082","url":null,"abstract":"<div><p>Many terrestrial microbes have evolved cell behaviors that help them rise above their substrate, often to facilitate dispersal. One example of these behaviors is found in the amoebae of <em>Sappinia pedata</em>, which actively lift most of their cell mass above the substrate, known as standing. This standing behavior was first described in <em>S. pedata</em> in the 1890s from horse dung isolates but never molecularly characterized from dung. Our study expands this understanding, revealing the first molecularly confirmed <em>S. pedata</em> from herbivore dung in Mississippi, USA, and describing a new species, <em>Sappinia dangeardi</em> n. sp., with larger trophozoite cells. Additionally, we isolated another standing amoeba, <em>Thecamoeba homeri</em> n. sp., from soil, exhibiting a previously unreported “doughnut shape” transient behavior. In <em>S. dangeardi</em> n. sp., we discovered that standing is likely triggered by substrate drying, and that actin filaments actively localize in the “stalk” to support the standing cells, as observed through confocal microscopy. While the purpose of standing behaviors has not been investigated, we hypothesize it is energetically expensive and therefore a significant evolutionary strategy in these organisms. Overall, this study emphasizes behavioral adaptations to terrestrial environments within Amoebozoa, stressing the importance of diverse laboratory conditions that replicate natural habitats.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126082"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140824663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ran Li , Wenbao Zhuang , Xiaochen Feng , Xiaoxuan Zhu , Xiaozhong Hu
{"title":"Morphology and molecular phylogeny of three Parasonderia species including a new species (Ciliophora, Plagiopylea)","authors":"Ran Li , Wenbao Zhuang , Xiaochen Feng , Xiaoxuan Zhu , Xiaozhong Hu","doi":"10.1016/j.ejop.2024.126087","DOIUrl":"10.1016/j.ejop.2024.126087","url":null,"abstract":"<div><p>Ciliates of the class Plagiopylea play a vital role in various anaerobic environments as consumers of prokaryotes. Yet, the diversity and phylogeny of this group of ciliates, especially marine representatives, remain poorly known. In this study, three <em>Parasonderia</em> species, viz., <em>Parasonderia elongata</em> spec. nov., and the already known <em>P. cyclostoma</em> and <em>P. vestita</em>, discovered in anaerobic sediments from various intertidal zones in China, were investigated based on their living morphology, infraciliature, and small subunit ribosomal rRNA gene sequences. <em>Parasonderia elongata</em> can be recognized by its larger body size, elongated body shape, oval oral opening, number of oral kineties, and significantly shortened leftmost postbuccal polykineties on the cell surface. Improved diagnosis and redescription of <em>P. cyclostoma</em> is provided for the first time, including data on infraciliature and molecular sequence. Phylogenetic analyses revealed that the three species cluster together and with the sequence of a Chinese population of <em>P. vestita</em> already present in the GenBank database, forming a robust clade.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126087"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140956949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eduarda de Souza-Maciel, Luiz Fernando Carvalho-Kelly, Anita Leocadio Freitas-Mesquita, José Roberto Meyer-Fernandes
{"title":"The ecto-3′-nucleotidase activity of Acanthamoeba castellanii trophozoites increases their adhesion to host cells through the generation of extracellular adenosine","authors":"Eduarda de Souza-Maciel, Luiz Fernando Carvalho-Kelly, Anita Leocadio Freitas-Mesquita, José Roberto Meyer-Fernandes","doi":"10.1016/j.ejop.2024.126086","DOIUrl":"https://doi.org/10.1016/j.ejop.2024.126086","url":null,"abstract":"<div><p><em>Acanthamoeba castellanii</em>, a free-living amoeba, can be pathogenic to humans causing a corneal infection named <em>Acanthamoeba</em> keratitis (AK). The mannose-binding protein (MBP) is well established as the major factor related to <em>Acanthamoeba</em> pathogenesis. However, additional factors that participate in the adhesion process and protect trophozoites from cytolytic effects caused by host immune responses remain unknown. Ectonucleotidases, including 3′-nucleotidase/nuclease (3′-NT/NU), a bifunctional enzyme that was recently reported in <em>A. castellanii</em>, are frequently related to the establishment of parasitic infections. We verified that trophozoites can hydrolyze 3′-AMP, and this activity is similar to that observed in other protists. The addition of 3′-AMP increases the adhesion of trophozoites to LLC-MK2 epithelial cells, and this stimulation is completely reversed by DTT, an inhibitor of ecto-3′-nucleotidase activity. Lesions in corneal cells caused by AK infection may elevate the extracellular level of 3′-AMP. We believe that ecto-3′-nucleotidase activity can modulate the host immune response, thus facilitating the establishment of parasitic infection. This activity results from the generation of extracellular adenosine, which can bind to purinergic receptors present in host immune cells. Positive feedback may occur in this cascade of events once the ecto-3′-nucleotidase activity of trophozoites is increased by the adhesion of trophozoites to LLC-MK2 cells.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126086"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140813171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kevin McKinley , Anastasios D. Tsaousis , Sonja Rückert
{"title":"Description and prevalence of gregarines infecting the amphipod Gammarus pulex, in the Water of Leith, Scotland, UK","authors":"Kevin McKinley , Anastasios D. Tsaousis , Sonja Rückert","doi":"10.1016/j.ejop.2024.126084","DOIUrl":"10.1016/j.ejop.2024.126084","url":null,"abstract":"<div><p>Gregarines are symbiotic protists that are found in a broad spectrum of invertebrates, including insects, crustaceans, and annelids. Among these the globally distributed amphipod <em>Gammarus pulex</em> is one of the earliest recognized hosts for aquatic gregarines and is prevalent among macroinvertebrates in freshwater environments. In this study, samples of <em>G. pulex</em> were collected in the Water of Leith river, Scotland, UK. Gregarines were identified using light and scanning electron microscopy as well as standard molecular techniques. We identified three septate eugregarine symbionts—<em>Heliospora longissima</em>, <em>Cephaloidophora gammari</em>, and the here newly characterized <em>Cephaloidophora conus</em> n. sp. (formerly <em>Cephaloidophora</em> sp.) associated with <em>Gammarus pulex</em> in the Water of Leith. Prevalences for identified gregarine species were calculated and seasonal dynamics of gregarine infections/colonization were analyzed. Prevalences were highest in autumn and spring reaching almost 50 %. While the two <em>Cephaloidophora</em> species showed similar colonization patterns, the prevalence of <em>Heliospora</em> showed an opposite trend. Identifying gregarine infection/colonization patterns is one step towards better understanding the gregarine–host relationship, as well as possible impacts of the gregarines on their hosts.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126084"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000348/pdfft?md5=7e5f9f7d71af9f1c7707d225f798a1c4&pid=1-s2.0-S0932473924000348-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140765910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Morphological reconstruction during cell regeneration in the ciliate Spirostomum ambiguum","authors":"Maho Shimada , Masashi M. Hayakawa , Toshinobu Suzaki , Hideki Ishida","doi":"10.1016/j.ejop.2024.126079","DOIUrl":"10.1016/j.ejop.2024.126079","url":null,"abstract":"<div><p>When the ciliate <em>Spirostomum ambiguum</em> is transected into two pieces, both fragments regenerate and proliferate. In the anterior fragments, which have lost their contractile vacuoles due to transection, new contractile vacuoles were formed at their posterior ends in a few minutes. When the cells were cut into three pieces, new contractile vacuoles were formed in the anterior and middle fragments, both at their posterior ends. Thus, the anterior-posterior axis of <em>S. ambiguum</em> was maintained after transection. Morphological repair, including the formation of the contractile vacuole, was also observed when only the anteriormost portion was transected to cut out a small fragment that did not contain part of the macronucleus. Scanning electron microscopy was performed to observe changes in the shape of the cleavage surface of <em>S. ambiguum</em> during the wound healing process. Within minutes after cutting, the cut surface was covered with a cilia-free membrane, preventing leakage of cytoplasmic contents. The surface of the cut area then rounded with time and was covered with cilia, completing the repair of the cut area in about one day.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126079"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140399204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniele Corsaro , Martin Mrva , Philippe Colson , Julia Walochnik
{"title":"Validation and redescription of Acanthamoeba terricola Pussard, 1964 (Amoebozoa: Acanthamoebidae)","authors":"Daniele Corsaro , Martin Mrva , Philippe Colson , Julia Walochnik","doi":"10.1016/j.ejop.2024.126091","DOIUrl":"10.1016/j.ejop.2024.126091","url":null,"abstract":"<div><p><em>Acanthamoeba castellanii</em> (Douglas, 1930) Page, 1967 is the type species of a widespread genus of free-living amoebae, potentially pathogenic for humans and animals. The Neff strain is one of the most widely used in biological research, serving as a model for both <em>A. castellanii</em> and the whole genus in general. The Neff strain, isolated in California, closely resembles another strain found in France and originally described as a separate species, <em>Acanthamoeba terricola</em> Pussard, 1964, but both were successively synonymized with <em>A. castellanii</em>. Molecular sequence analysis has largely replaced morphological diagnosis for species identification in <em>Acanthamoeba</em>, and rDNA phylogenies show that the Neff strain forms a distinct lineage from that of the type strain of <em>A. castellanii</em>. In this study, we compared the type strain of <em>A. terricola</em> with the Neff strain and <em>A. castellanii</em>, and analysed the available molecular data including new sequences obtained from <em>A. terricola</em>. Here we provide molecular evidence to validate the species <em>A. terricola</em>. The Neff strain is therefore transferred to <em>A. terricola</em> and should no longer be considered as belonging to <em>A. castellanii</em>.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126091"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141031470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Awais Ali , Ning Wang , Qiaoling Wang , Guangjian Xu , Henglong Xu
{"title":"An approach to evaluating seasonal responses to acute toxicity of antibiotic nitrofurazone on periphytic ciliated protist communities in marine environments","authors":"Awais Ali , Ning Wang , Qiaoling Wang , Guangjian Xu , Henglong Xu","doi":"10.1016/j.ejop.2024.126081","DOIUrl":"https://doi.org/10.1016/j.ejop.2024.126081","url":null,"abstract":"<div><p>Periphytic protists including ciliates are the primary components of microbial communities in which they play a vital role in the progression of food webs by moving resources from lower to higher trophic levels. However, the toxic effects of veterinary antibiotics on periphytic protists across four seasons are minimally understood. Therefore, in this study, a 1-year survey was conducted with the antibiotic nitrofurazone (NFZ) applied at concentrations of 0.0, 1.5, 3.0, 6.0, and 12.0 mg/L. Samples of protist communities were collected using microscope glass slides during four seasons in the coastal waters of the Yellow Sea, Qingdao, northern China. The abundance of protists dropped with an increase in NFZ concentrations, and almost all species were dead at a concentration of 12.0 mg/L. The 12 h-<em>LC<sub>50</sub></em> values of NFZ for the protist biota were similar among the four seasons, despite significant seasonal variability in the community structure. The present results suggest that the periphytic protist biota may be used as a biomarker for assessing the ecotoxicity of NFZ in marine environments regardless of the year season.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126081"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140552655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Homo- and hetero-oligomeric protein–protein associations explain autocrine and heterologous pheromone-cell interactions in Euplotes","authors":"Claudio Alimenti , Bill Pedrini , Pierangelo Luporini , Yaohan Jiang , Adriana Vallesi","doi":"10.1016/j.ejop.2024.126075","DOIUrl":"10.1016/j.ejop.2024.126075","url":null,"abstract":"<div><p>In <em>Euplotes</em>, protein pheromones regulate cell reproduction and mating by binding cells in autocrine or heterologous fashion, respectively. Pheromone binding sites (receptors) are identified with membrane-bound pheromone isoforms determined by the same genes specifying the soluble forms, establishing a structural equivalence in each cell type between the two twin proteins. Based on this equivalence, autocrine and heterologous pheromone/receptor interactions were investigated analyzing how native molecules of pheromones E<em>r</em>-1 and E<em>r</em>-13, distinctive of mating compatible <em>E. raikovi</em> cell types, associate into crystals. E<em>r</em>-1 and E<em>r</em>-13 crystals are equally formed by molecules that associate cooperatively into oligomeric chains rigorously taking a mutually opposite orientation, and each burying two interfaces. A minor interface is pheromone-specific, while a major one is common in E<em>r</em>-1 and E<em>r</em>-13 crystals. A close structural inspection of this interface suggests that it may be used by E<em>r</em>-1 and E<em>r</em>-13 to associate into heterodimers, yet inapt to further associate into higher complexes. Pheromone-molecule homo-oligomerization into chains accounts for clustering and internalization of autocrine pheromone/receptor complexes in growing cells, while the heterodimer unsuitability to oligomerize may explain why heterologous pheromone/receptor complexes fail clustering and internalization. Remaining on the cell surface, they are credited with a key role in cell–cell mating adhesion.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126075"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000257/pdfft?md5=82e08cb8220c05d2e4f00c51e6326a24&pid=1-s2.0-S0932473924000257-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140181978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}