{"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}
Patrick J. Keeling , Mahara Mtawali , Morelia Trznadel , Samuel J. Livingston , Kevin C. Wakeman
{"title":"Parallel functional reduction in the mitochondria of apicomplexan parasites","authors":"Patrick J. Keeling , Mahara Mtawali , Morelia Trznadel , Samuel J. Livingston , Kevin C. Wakeman","doi":"10.1016/j.ejop.2024.126065","DOIUrl":"10.1016/j.ejop.2024.126065","url":null,"abstract":"<div><p>Extreme functional reduction of mitochondria has taken place in parallel in many distantly related lineages of eukaryotes, leading to a number of recurring metabolic states with variously lost electron transport chain (ETC) complexes, loss of the tricarboxylic acid (TCA) cycle, and/or loss of the mitochondrial genome. The resulting mitochondria-related organelles (MROs) are generally structurally reduced and in the most extreme cases barely recognizable features of the cell with no role in energy metabolism whatsoever (e.g., mitosomes, which generally only make iron-sulfur clusters). Recently, a wide diversity of MROs were discovered to be hiding in plain sight: in gregarine apicomplexans. This diverse group of invertebrate parasites has been known and observed for centuries, but until recent applications of culture-free genomics, their mitochondria were unremarkable. The genomics, however, showed that mitochondrial function has reduced in parallel in multiple gregarine lineages to several different endpoints, including the most reduced mitosomes. Here we review this remarkable case of parallel evolution of MROs, and some of the interesting questions this work raises.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"94 ","pages":"Article 126065"},"PeriodicalIF":2.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000154/pdfft?md5=2fa0d50d9ef35d502b12047cc59ed12b&pid=1-s2.0-S0932473924000154-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140129340","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}
Zhaorui Zhou , Chao Li , Qingxiang Yuan , Yong Chi , Yuqing Li , Ying Yan , Saleh A. Al-Farraj , Naomi A. Stover , Zigui Chen , Xiao Chen
{"title":"Single-cell transcriptomic analysis reveals genome evolution in predatory litostomatean ciliates","authors":"Zhaorui Zhou , Chao Li , Qingxiang Yuan , Yong Chi , Yuqing Li , Ying Yan , Saleh A. Al-Farraj , Naomi A. Stover , Zigui Chen , Xiao Chen","doi":"10.1016/j.ejop.2024.126062","DOIUrl":"https://doi.org/10.1016/j.ejop.2024.126062","url":null,"abstract":"<div><p>Many ciliated protists prey on other large microbial organisms, including other protists and microscopic metazoans. The ciliate class Litostomatea unites both predatory and endosymbiotic species. The evolution of predation ability in ciliates remains poorly understood, in part, due to a lack of genomic data. To fill this gap, we acquired the transcriptome profiles of six predatory litostomateans using single-cell sequencing technology and investigated their transcriptomic features. Our results show that: (1) in contrast to non-predatory ciliates, the predatory litostomateans have expanded gene families associated with transmembrane activity and reactive oxidative stress response pathways, potentially as a result of cellular behaviors such as fast contraction and extension; (2) the expansion of the calcium-activated BK potassium channel gene family, which hypothetically regulates cell contractility, is an ancient evolutionary event for the class Litostomatea, suggesting a rewired metabolism associated with the hunting behavior of predatory ciliates; and (3) three whole genome duplication (WGD) events have been detected in litostomateans, with genes associated with biosynthetic processes, transmembrane activity, and calcium-activated potassium channel activity being retained during the WGD events. In addition, we explored the evolutionary relationships among 17 ciliate species, including eight litostomateans, and provided a rich foundational dataset for future in-depth phylogenomic studies of Litostomatea. Our comprehensive analyses suggest that the rewired cellular metabolism via expanded gene families and WGD events might be the potential genetic basis for the predation ability of raptorial ciliates.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"93 ","pages":"Article 126062"},"PeriodicalIF":2.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139748116","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}
Siobhon Egan , Amanda D. Barbosa , Yaoyu Feng , Lihua Xiao , Una Ryan
{"title":"Minimal zoonotic risk of cryptosporidiosis and giardiasis from frogs and reptiles","authors":"Siobhon Egan , Amanda D. Barbosa , Yaoyu Feng , Lihua Xiao , Una Ryan","doi":"10.1016/j.ejop.2024.126066","DOIUrl":"https://doi.org/10.1016/j.ejop.2024.126066","url":null,"abstract":"<div><p>The zoonotic potential of the protist parasites <em>Cryptosporidium</em> spp. and <em>Giardia duodenalis</em> in amphibians and reptiles raises public health concerns due to their growing popularity as pets. This review examines the prevalence and diversity of these parasites in wild and captive amphibians and reptiles to better understand the zoonotic risk. Research on <em>Giardia</em> in both groups is limited, and zoonotic forms of <em>Cryptosporidium</em> or <em>Giardia</em> have not been reported in amphibians. Host-adapted <em>Cryptosporidium</em> species dominate in reptiles, albeit some reptiles have been found to carry zoonotic (<em>C. hominis</em> and <em>C. parvum</em>) and rodent-associated (<em>C. tyzzeri</em>, <em>C. muris</em> and <em>C. andersoni</em>) species, primarily through mechanical carriage. Similarly, the limited reports of <em>Giardia duodenalis</em> (assemblages A, B and E) in reptiles may also be due to mechanical carriage. Thus, the available evidence indicates minimal zoonotic risk associated with these organisms in wild and captive frogs and reptiles. The exact transmission routes for these infections within reptile populations remain poorly understood, particularly regarding the importance of mechanical carriage. Although the risk appears minimal, continued research and surveillance efforts are necessary to gain a more comprehensive understanding of the transmission dynamics and ultimately improve our ability to safeguard human and animal health.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"93 ","pages":"Article 126066"},"PeriodicalIF":2.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000166/pdfft?md5=f2d522799f5a06cf61e0671be64349cf&pid=1-s2.0-S0932473924000166-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140031379","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":"Redescription and molecular phylogeny of Trochilia sigmoides Dujardin, 1841 (Ciliophora, Cyrtophoria) collected from South Korea","authors":"Ji Hye Choi , Atef Omar , Jae-Ho Jung","doi":"10.1016/j.ejop.2024.126067","DOIUrl":"https://doi.org/10.1016/j.ejop.2024.126067","url":null,"abstract":"<div><p>During a survey of Korean marine ciliates, <em>Trochilia sigmoides</em>, the type species of the genus <em>Trochilia</em>, was collected and examined using in vivo observation and protargol impregnation. Moreover, scanning electron microscopy and 18S rRNA gene sequencing have been applied for the first time to study this species. Morphologically, <em>T. sigmoides</em> is characterized by the small body size, the oval body outline, and the spiral dorsal ridges. The Korean population of <em>T. sigmoides</em> shows only minute differences to other populations reported in the literature, mainly in body size and the number of dorsal ridges. Phylogenetic analyses based on 18S rRNA gene sequences show that <em>T. sigmoides</em> and <em>T. petrani</em> are placed together with two members of the family Kyaroikeidae, causing the family Dysteriidae to be non-monophyletic. The present new data increase the knowledge about the morphology and phylogeny of the genus <em>Trochilia</em> and would assist in understanding the phylogenetic relationship between the free-living Dysteriidae and the parasitic Kyaroikeidae.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"93 ","pages":"Article 126067"},"PeriodicalIF":2.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140042490","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}
Hui Wang , Peiling Wu , Lu Xiong , Han-Sol Kim , Jin Ho Kim , Jang-Seu Ki
{"title":"Nuclear genome of dinoflagellates: Size variation and insights into evolutionary mechanisms","authors":"Hui Wang , Peiling Wu , Lu Xiong , Han-Sol Kim , Jin Ho Kim , Jang-Seu Ki","doi":"10.1016/j.ejop.2024.126061","DOIUrl":"10.1016/j.ejop.2024.126061","url":null,"abstract":"<div><p>Recent progress in high-throughput sequencing technologies has dramatically increased availability of genome data for prokaryotes and eukaryotes. Dinoflagellates have distinct chromosomes and a huge genome size, which make their genomic analysis complicated. Here, we reviewed the nuclear genomes of core dinoflagellates, focusing on the genome and cell size. Till now, the genome sizes of several dinoflagellates (more than 25) have been measured by certain methods (e.g., flow cytometry), showing a range of 3–250 pg of genomic DNA per cell. In contrast to their relatively small cell size, their genomes are huge (about 1–80 times the human haploid genome). In the present study, we collected the genome and cell size data of dinoflagellates and compared their relationships. We found that dinoflagellate genome size exhibits a positive correlation with cell size. On the other hand, we recognized that the genome size is not correlated with phylogenetic relatedness. These may be caused by genome duplication, increased gene copy number, repetitive non-coding DNA, transposon expansion, horizontal gene transfer, organelle-to-nucleus gene transfer, and/or mRNA reintegration into the genome. Ultimate verification of these factors as potential causative mechanisms would require sequencing of more dinoflagellate genomes in the future.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"93 ","pages":"Article 126061"},"PeriodicalIF":2.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139680308","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}
Martina Foučková, Kristýna Uhrová, Aneta Kubánková, Tomáš Pánek, Ivan Čepička
{"title":"Lighting lantern above Psalteriomonadidae: Unveiling novel diversity within the genus Psalteriomonas (Discoba: Heterolobosea)","authors":"Martina Foučková, Kristýna Uhrová, Aneta Kubánková, Tomáš Pánek, Ivan Čepička","doi":"10.1016/j.ejop.2024.126052","DOIUrl":"10.1016/j.ejop.2024.126052","url":null,"abstract":"<div><p><span><span>Psalteriomonadidae are a small family of anaerobic free-living protists<span> belonging to Heterolobosea, Discoba. We cultured 74 new strains of mostly amoeboid Psalteriomonadidae obtained from mainly freshwater habitats and sequenced their 18S </span></span>rRNA gene<span>. Based on the phylogenetic analysis and genetic distances, we report multiple novel species, four of which we formally describe based on the light-microscopic morphology (</span></span><em>Psalteriomonas minuta</em>, <em>P. australis</em>, <em>P. fimbriata</em>, and <em>P. parva</em>). We also examined the ultrastructure of two <em>Psalteriomonas</em><span> species using transmission electron microscopy. We transfer </span><em>Sawyeria marylandensis</em> into the genus <em>Psalteriomonas</em> and synonymize <em>Sawyeria</em> with <em>Psalteriomonas.</em> In addition, we studied the flagellate stage of <em>P. marylandensis</em> comb. nov. for the first time, using light and scanning electron microscopy.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"93 ","pages":"Article 126052"},"PeriodicalIF":2.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139410472","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}