Pub Date : 2025-12-05DOI: 10.1016/j.ejop.2025.126176
Jana Kohl-Chandramohan , Michael Schweikert , Tobias Junginger , Ingo Hartenbach , Norbert Klaas , Marie-Louise Lemloh
The mechanisms of bioaccumulation in eukaryotic cells, along with the understanding of pathways and metal binding, are fundamental to advances in both basic and applied research. The ciliate Tetrahymena pyriformis bioaccumulates the rare earth element gadolinium (Gd) into food vacuoles and subsequently excretes Gd-containing particles. We investigated the uptake mechanism of Gd in detail and characterised the properties of the resulting biogenic particles. Our results demonstrate that T. pyriformis accumulates Gd3+ ions via phagocytosis, with components of the organic cell culture medium playing a central role in mediating the uptake of Gd3+ ions. Bioaccumulation occurred in cells cultivated in Gd3+-containing environmental water samples and in standard cell culture medium containing proteose peptone, but was absent when Gd3+ ions were applied in complexed form, such as gadolinium-based contrast agents. The bioaccumulated and excreted microparticles are amorphous, display magnetic properties, and can be isolated. They consist of about 70 wt% amorphous gadolinium phosphate, 25–27 wt% organic material, and 3 wt% combined Ca, K, Mg, and Na. The individual components can be fractionated based on their solubility. These insights into microbial bioaccumulation of metal elements enhance our understanding of environmental elemental cycles and could provide new strategies for element recovery.
{"title":"Bioaccumulation of gadolinium in Tetrahymena: Phagocytotic uptake leads to the formation of gadolinium phosphate–organic composite particles","authors":"Jana Kohl-Chandramohan , Michael Schweikert , Tobias Junginger , Ingo Hartenbach , Norbert Klaas , Marie-Louise Lemloh","doi":"10.1016/j.ejop.2025.126176","DOIUrl":"10.1016/j.ejop.2025.126176","url":null,"abstract":"<div><div>The mechanisms of bioaccumulation in eukaryotic cells, along with the understanding of pathways and metal binding, are fundamental to advances in both basic and applied research. The ciliate <em>Tetrahymena pyriformis</em> bioaccumulates the rare earth element gadolinium (Gd) into food vacuoles and subsequently excretes Gd-containing particles. We investigated the uptake mechanism of Gd in detail and characterised the properties of the resulting biogenic particles. Our results demonstrate that <em>T. pyriformis</em> accumulates Gd<sup>3+</sup> ions via phagocytosis, with components of the organic cell culture medium playing a central role in mediating the uptake of Gd<sup>3+</sup> ions. Bioaccumulation occurred in cells cultivated in Gd<sup>3+</sup>-containing environmental water samples and in standard cell culture medium containing proteose peptone, but was absent when Gd<sup>3+</sup> ions were applied in complexed form, such as gadolinium-based contrast agents. The bioaccumulated and excreted microparticles are amorphous, display magnetic properties, and can be isolated. They consist of about 70 wt% amorphous gadolinium phosphate, 25–27 wt% organic material, and 3 wt% combined Ca, K, Mg, and Na. The individual components can be fractionated based on their solubility. These insights into microbial bioaccumulation of metal elements enhance our understanding of environmental elemental cycles and could provide new strategies for element recovery.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"102 ","pages":"Article 126176"},"PeriodicalIF":1.6,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145750087","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}
Pub Date : 2025-12-05DOI: 10.1016/j.ejop.2025.126177
Shisi Zhang , Shunhai Zhu , Wenhao Huang , Qiping Zhao , Lu Wang , Hui Dong , Jenwen Wang , Yu Yu , Hongyu Han
Avian coccidiosis is an important intestinal disease caused by Eimeria spp., which leads to significant economic losses in the poultry industry. Although anticoccidial drugs can effectively control it in intensive farming, their extensive and irrational use has induced drug resistance in Eimeria species. Our previous RNA-seq study revealed differential expression of the enoyl-CoA hydratase/isomerase family protein (EtECHI) between drug-sensitive (DS) and drug-resistant Eimeria tenella strains. In this study, qPCR analysis showed that EtECHI mRNA levels were significantly upregulated in diclazuril-resistant (DZR) and maduramicin-resistant (MRR) strains compared to the DS strain. Furthermore, EtECHI transcription increased progressively with rising concentrations of MRR and DZR. Additionally, EtECHI transcript levels were significantly higher in field-isolated diclazuril-resistant strains than in the DS strain. qPCR and western blot analyses showed that EtECHI expression levels were highest in E. tenella unsporulated oocysts. Indirect immunofluorescence assays (IFA) revealed that EtECHI was primarily localized in the cytoplasm of the parasite, with additional surface distribution. An in vitro inhibition assay demonstrated that anti-rEtECHI polyclonal antibodies significantly reduced E. tenella sporozoites' invasion of DF-1 cells. These findings suggest that EtECHI may be associated with the drug resistance of E. tenella and may play a role in parasite growth and development within host cells.
{"title":"Molecular characterization and analysis of enoyl-CoA hydratase/isomerase family protein of Eimeria tenella","authors":"Shisi Zhang , Shunhai Zhu , Wenhao Huang , Qiping Zhao , Lu Wang , Hui Dong , Jenwen Wang , Yu Yu , Hongyu Han","doi":"10.1016/j.ejop.2025.126177","DOIUrl":"10.1016/j.ejop.2025.126177","url":null,"abstract":"<div><div>Avian coccidiosis is an important intestinal disease caused by <em>Eimeria</em> spp., which leads to significant economic losses in the poultry industry. Although anticoccidial drugs can effectively control it in intensive farming, their extensive and irrational use has induced drug resistance in <em>Eimeria</em> species. Our previous RNA-seq study revealed differential expression of the enoyl-CoA hydratase/isomerase family protein (<em>Et</em>ECHI) between drug-sensitive (DS) and drug-resistant <em>Eimeria tenella</em> strains. In this study, qPCR analysis showed that <em>Et</em>ECHI mRNA levels were significantly upregulated in diclazuril-resistant (DZR) and maduramicin-resistant (MRR) strains compared to the DS strain. Furthermore, <em>Et</em>ECHI transcription increased progressively with rising concentrations of MRR and DZR. Additionally, <em>Et</em>ECHI transcript levels were significantly higher in field-isolated diclazuril-resistant strains than in the DS strain. qPCR and western blot analyses showed that <em>Et</em>ECHI expression levels were highest in <em>E. tenella</em> unsporulated oocysts. Indirect immunofluorescence assays (IFA) revealed that <em>Et</em>ECHI was primarily localized in the cytoplasm of the parasite, with additional surface distribution. An in vitro inhibition assay demonstrated that anti-r<em>Et</em>ECHI polyclonal antibodies significantly reduced <em>E. tenella</em> sporozoites' invasion of DF-1 cells. These findings suggest that <em>Et</em>ECHI may be associated with the drug resistance of <em>E. tenella</em> and may play a role in parasite growth and development within host cells.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"102 ","pages":"Article 126177"},"PeriodicalIF":1.6,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712002","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}
The genus Bothrostoma Stokes, 1887 appears more diverse than previously reported. Recent studies have uncovered several new species, yet the full extent of its diversity remains to be revealed. In this study, we describe two new species, Bothrostoma longicilia nov. sp. and B. dextroproboscis nov. sp., collected from freshwater ponds in South Korea. Their characterization was conducted using both morphological and molecular approaches. Bothrostoma longicilia nov. sp. is distinguished by a combination of prominent caudal cilia, a short acute snout, 30–40 somatic kineties (including 11–15 postoral kineties), and cortical granules arranged in 7–8 discontinuous oblique rows between adjacent somatic kineties. Bothrostoma dextroproboscis nov. sp. is characterized by a rectangular shape, with the anterior left end terminating in a short acute snout and the right anterior end extended into a flexible proboscis, an oblong macronucleus, and an adoral zone of membranelles extending over approximately two-thirds of the body length. Molecular phylogenetic analysis based on SSU rDNA sequences supports the distinctness of these two new species and confirms the monophyly of the genus Bothrostoma.
{"title":"Step-by-step exploration of the diversity of the genus Bothrostoma Stokes, 1887 (Ciliophora, Armophorea) in Korea using morphological and molecular analyses","authors":"Quoc Dung Nguyen, Nanda Dwi Kristanti, Novia Cahyani, Mann Kyoon Shin","doi":"10.1016/j.ejop.2025.126174","DOIUrl":"10.1016/j.ejop.2025.126174","url":null,"abstract":"<div><div>The genus <em>Bothrostoma</em> Stokes, 1887 appears more diverse than previously reported. Recent studies have uncovered several new species, yet the full extent of its diversity remains to be revealed. In this study, we describe two new species, <em>Bothrostoma longicilia</em> nov. sp. and <em>B. dextroproboscis</em> nov. sp., collected from freshwater ponds in South Korea. Their characterization was conducted using both morphological and molecular approaches. <em>Bothrostoma longicilia</em> nov. sp. is distinguished by a combination of prominent caudal cilia, a short acute snout, 30–40 somatic kineties (including 11–15 postoral kineties), and cortical granules arranged in 7–8 discontinuous oblique rows between adjacent somatic kineties. <em>Bothrostoma dextroproboscis</em> nov. sp. is characterized by a rectangular shape, with the anterior left end terminating in a short acute snout and the right anterior end extended into a flexible proboscis, an oblong macronucleus, and an adoral zone of membranelles extending over approximately two-thirds of the body length. Molecular phylogenetic analysis based on SSU rDNA sequences supports the distinctness of these two new species and confirms the monophyly of the genus <em>Bothrostoma</em>.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"102 ","pages":"Article 126174"},"PeriodicalIF":1.6,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712001","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}
Pub Date : 2025-11-24DOI: 10.1016/j.ejop.2025.126173
Alena D. Firsova, Anna Y. Bessudova, Yelena V. Likhoshway
Among the diverse morphotypes of siliceous stomatocysts, not all producer species have been identified. Using scanning electron microscopy, we determined the species affiliation of two Paraphysomonas stomatocyst morphotypes based on the presence of species-specific siliceous scales on their surfaces. A new morphotype, Stomatocyst 514 Firsova & Bessudova, is formally described, and its relationship to Paraphysomonas circumvallata Thomsen was established on the basis of attached plate-scales. The previously described morphotype Stomatocyst 52 Duff & Smol, 1991 emend. Duff et al., 1995 is related to the species Paraphysomonas corynephora. The ecology of these two species differs considerably: cyst formation in P. circumvallata was observed in the southern basin of Lake Baikal in August at a water temperature of 14.3 °C, whereas P. corynephora formed cysts in the Angara River in May at 4.8 °C. These findings expand the potential for analyzing the biogeography of these species and may be applied to paleoclimatic reconstructions. The morphological diversity and ultrastructural features of all currently known stomatocyst morphotypes within the genus Paraphysomonas are discussed, and an updated identification key is provided.
{"title":"Ultrastructural data on stomatocysts of the genus Paraphysomonas (Chrysophyceae, Paraphysomonadales), including description of one new morphotype and identification of a new producer of Stomatocyst 52","authors":"Alena D. Firsova, Anna Y. Bessudova, Yelena V. Likhoshway","doi":"10.1016/j.ejop.2025.126173","DOIUrl":"10.1016/j.ejop.2025.126173","url":null,"abstract":"<div><div>Among the diverse morphotypes of siliceous stomatocysts, not all producer species have been identified. Using scanning electron microscopy, we determined the species affiliation of two <em>Paraphysomonas</em> stomatocyst morphotypes based on the presence of species-specific siliceous scales on their surfaces. A new morphotype, Stomatocyst 514 Firsova & Bessudova, is formally described, and its relationship to <em>Paraphysomonas circumvallata</em> Thomsen was established on the basis of attached plate-scales. The previously described morphotype Stomatocyst 52 Duff & Smol, 1991 emend. Duff et al., 1995 is related to the species <em>Paraphysomonas corynephora</em>. The ecology of these two species differs considerably: cyst formation in <em>P. circumvallata</em> was observed in the southern basin of Lake Baikal in August at a water temperature of 14.3 °C, whereas <em>P. corynephora</em> formed cysts in the Angara River in May at 4.8 °C. These findings expand the potential for analyzing the biogeography of these species and may be applied to paleoclimatic reconstructions. The morphological diversity and ultrastructural features of all currently known stomatocyst morphotypes within the genus <em>Paraphysomonas</em> are discussed, and an updated identification key is provided.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"102 ","pages":"Article 126173"},"PeriodicalIF":1.6,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712003","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}
This study aims to investigate the seasonal variation in growth and physiology of Chlorella sorokiniana UCAM 001 strain using annual optimization monitoring with a groundwater medium in two outdoor flat-plate photobioreactors (PBRs), which were first scaled up at the Faculty of Sciences Semlalia (Marrakech, Morocco). The culture medium was adjusted to ensure non-limiting nutrient concentrations (10 mg·L−1 and 100 mg·L−1 of additional phosphorus and nitrate, respectively). Temperature, light, and algal growth were monitored daily. Proline, glycine betaine, and catalase levels were measured every four days to assess the degree of algal stress. Biomass productivity increased during spring, reaching 30 mg·L−1·day−1 with a specific growth rate of 0.73 day−1. However, no growth was observed during the summer. Physiological analysis revealed increased proline and glycine betaine levels during autumn and winter due to temperatures as low as 13 °C. In contrast, catalase concentration peaked in spring. Pearson correlation analysis indicated that nutrient limitation, together with temperature and light intensity, induced stress in C. sorokiniana, stimulating catalase production. Algal growth efficiently removed nutrients from the medium, achieving removal rates of 97 % for total phosphorus and 87 % for total nitrogen. Optimized cooling systems will improve PBR efficiency and support algal growth under extreme summer conditions.
本研究旨在利用地下水介质在两个室外平板光生物反应器(pbr)中进行年度优化监测,研究sorokiniana小球藻UCAM 001菌株生长和生理的季节变化。这两个室外平板光生物反应器是在Semlalia科学学院(Marrakech, Morocco)首次扩大规模的。调整培养基以确保非限制营养浓度(磷和硝酸盐分别为10 mg·L-1和100 mg·L-1)。每天监测温度、光照和藻类生长情况。每四天测量一次脯氨酸、甘氨酸甜菜碱和过氧化氢酶的水平,以评估藻类胁迫的程度。生物量生产力在春季增加,达到30 mg·L-1·d -1,比增长率为0.73 d -1。然而,在夏季没有观察到增长。生理分析显示,在秋季和冬季,由于温度低至13°C,脯氨酸和甘氨酸甜菜碱水平升高。过氧化氢酶浓度在春季达到峰值。Pearson相关分析表明,营养限制、温度和光照强度共同诱导了sorokiniana的胁迫,刺激了过氧化氢酶的产生。藻类生长有效地去除培养基中的营养物质,总磷和总氮的去除率分别达到97%和87%。优化的冷却系统将提高PBR效率,并在极端的夏季条件下支持藻类生长。
{"title":"Seasonal effects on Chlorella sorokiniana UCAM 001 growth and physiology in flat-plate photobioreactors in Morocco's arid climate","authors":"Aafaf Krimech , Sofyan Sbahi , Ouafa Cherifi , Abdessamad Hejjaj , Richard Mugani , Naaila Ouazzani , Martin Kerner , Brahim Oudra , Laila Mandi","doi":"10.1016/j.ejop.2025.126171","DOIUrl":"10.1016/j.ejop.2025.126171","url":null,"abstract":"<div><div>This study aims to investigate the seasonal variation in growth and physiology of <em>Chlorella sorokiniana</em> UCAM 001 strain using annual optimization monitoring with a groundwater medium in two outdoor flat-plate photobioreactors (PBRs), which were first scaled up at the Faculty of Sciences Semlalia (Marrakech, Morocco). The culture medium was adjusted to ensure non-limiting nutrient concentrations (10 mg·L<sup>−1</sup> and 100 mg·L<sup>−1</sup> of additional phosphorus and nitrate, respectively). Temperature, light, and algal growth were monitored daily. Proline, glycine betaine, and catalase levels were measured every four days to assess the degree of algal stress. Biomass productivity increased during spring, reaching 30 mg·L<sup>−1</sup>·day<sup>−1</sup> with a specific growth rate of 0.73 day<sup>−1</sup>. However, no growth was observed during the summer. Physiological analysis revealed increased proline and glycine betaine levels during autumn and winter due to temperatures as low as 13 °C. In contrast, catalase concentration peaked in spring. Pearson correlation analysis indicated that nutrient limitation, together with temperature and light intensity, induced stress in <em>C. sorokiniana</em>, stimulating catalase production. Algal growth efficiently removed nutrients from the medium, achieving removal rates of 97 % for total phosphorus and 87 % for total nitrogen. Optimized cooling systems will improve PBR efficiency and support algal growth under extreme summer conditions.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"101 ","pages":"Article 126171"},"PeriodicalIF":1.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145312736","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}
Pub Date : 2025-10-01DOI: 10.1016/j.ejop.2025.126175
Zhicheng Li , Baotun Wang , Jingyu Zhuang , Anxing Li , Fei Yin
Amyloodinium ocellatum is a parasitic dinoflagellate that infects marine fish in tropical and subtropical regions, causing significant economic losses in aquaculture. This study used light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron tomography (ET) to comprehensively characterize the morphology, ultrastructure, and specialized attachment apparatus of A. ocellatum trophonts. The trophonts primarily parasitized the gill filaments of infected fish, reaching 89.8 ± 10.3 μm after 48 h of infection. Under LM, trophonts appeared as dark, spherical or pear-shaped structures that remained stationary throughout the parasitic process. SEM revealed surface folds and persistent transverse grooves, while TEM identified starch granules, lipid droplets, accumulation bodies, and microtubules. Trophonts rapidly formed rhizoids post-infection, which branched into root-hair-like projections penetrating the host epithelium. These projections functioned both as anchors and nutrient absorbers. During parasitism, trophonts induced degeneration and necrosis of host cells, leading to sloughing of epithelial cells and wound formation. ET further demonstrated that trophonts possessed numerous root-hair-like projections that deeply infiltrated host cells. This study provides the first systematic description of the morphology and ultrastructure of A. ocellatum trophonts and sheds new light on the fine structural features of the parasite's attachment apparatus.
{"title":"Ultrastructural characterization of Amyloodinium ocellatum (Dinoflagellata): Insights into trophont morphology and parasitic mode","authors":"Zhicheng Li , Baotun Wang , Jingyu Zhuang , Anxing Li , Fei Yin","doi":"10.1016/j.ejop.2025.126175","DOIUrl":"10.1016/j.ejop.2025.126175","url":null,"abstract":"<div><div><em>Amyloodinium ocellatum</em> is a parasitic dinoflagellate that infects marine fish in tropical and subtropical regions, causing significant economic losses in aquaculture. This study used light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron tomography (ET) to comprehensively characterize the morphology, ultrastructure, and specialized attachment apparatus of <em>A. ocellatum</em> trophonts. The trophonts primarily parasitized the gill filaments of infected fish, reaching 89.8 ± 10.3 μm after 48 h of infection. Under LM, trophonts appeared as dark, spherical or pear-shaped structures that remained stationary throughout the parasitic process. SEM revealed surface folds and persistent transverse grooves, while TEM identified starch granules, lipid droplets, accumulation bodies, and microtubules. Trophonts rapidly formed rhizoids post-infection, which branched into root-hair-like projections penetrating the host epithelium. These projections functioned both as anchors and nutrient absorbers. During parasitism, trophonts induced degeneration and necrosis of host cells, leading to sloughing of epithelial cells and wound formation. ET further demonstrated that trophonts possessed numerous root-hair-like projections that deeply infiltrated host cells. This study provides the first systematic description of the morphology and ultrastructure of <em>A. ocellatum</em> trophonts and sheds new light on the fine structural features of the parasite's attachment apparatus.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"101 ","pages":"Article 126175"},"PeriodicalIF":1.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681484","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}
Pub Date : 2025-10-01DOI: 10.1016/j.ejop.2025.126172
Najla Baković , Ferry Siemensma , Maria Holzmann
Non-marine foraminifera are among the least-studied groups of protists due to their low population densities, patchy distribution, and spatiotemporal variability. This study investigated foraminifera from four caves within the Dinaric karst region of southeastern Europe, using both morphological and molecular methods. Our results confirm the presence of foraminifera in all examined caves. A new monothalamous foraminifer, Lacogromia cepelaki sp. nov., is described based on morphological and molecular data from Jopićeva Cave (Croatia). Three additional Lacogromia taxa are informally described from different caves. However, due to the lack of distinct morphological characteristics, their formal taxonomic description will require molecular analyses of live specimens. A further important outcome of this study is the morphological description of Spirolocammina petrae sp. nov., discovered in Miljacka II Cave (Croatia). This represents the first discovery of an agglutinated tubothalamid foraminifer adapted to a freshwater environment. As no molecular data could be obtained, its phylogenetic position remains undetermined, and further research will be necessary.
{"title":"Two new freshwater foraminiferal species (SAR, Rhizaria) from Dinaric karst caves (southeastern Europe)","authors":"Najla Baković , Ferry Siemensma , Maria Holzmann","doi":"10.1016/j.ejop.2025.126172","DOIUrl":"10.1016/j.ejop.2025.126172","url":null,"abstract":"<div><div>Non-marine foraminifera are among the least-studied groups of protists due to their low population densities, patchy distribution, and spatiotemporal variability. This study investigated foraminifera from four caves within the Dinaric karst region of southeastern Europe, using both morphological and molecular methods. Our results confirm the presence of foraminifera in all examined caves. A new monothalamous foraminifer, <em>Lacogromia cepelaki</em> sp. nov., is described based on morphological and molecular data from Jopićeva Cave (Croatia). Three additional <em>Lacogromia</em> taxa are informally described from different caves. However, due to the lack of distinct morphological characteristics, their formal taxonomic description will require molecular analyses of live specimens. A further important outcome of this study is the morphological description of <em>Spirolocammina petrae</em> sp. nov<em>.</em>, discovered in Miljacka II Cave (Croatia). This represents the first discovery of an agglutinated tubothalamid foraminifer adapted to a freshwater environment. As no molecular data could be obtained, its phylogenetic position remains undetermined, and further research will be necessary.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"101 ","pages":"Article 126172"},"PeriodicalIF":1.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145388066","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}
Pub Date : 2025-10-01DOI: 10.1016/j.ejop.2025.126168
Carla S.R. Huber , Luciano K. Huber , Sara H. Al-Hadidi , Talaat Ahmed , Sakeenah Adenan , Jane Oja , Amjad M. Shraim , Anna Ostapenko Alatalo , Mohammed Alsafran , Leho Tedersoo , Dana A. Abumaali , Laura R.P. Utz , Juha M. Alatalo
We investigated soil protist communities across five sites representing two characteristic dryland habitats in Qatar: rawdha and sabkha. Altogether, 100 samples were collected during a single field campaign; DNA was subsequently extracted, and the V4 region of the 18S rRNA gene was amplified. We obtained 112,529 high-quality sequences, taxonomically representing 1,524 TSAR (Telonemia, Stramenopila, Alveolata, Rhizaria) amplicon sequence variants. This approach enabled detection of diverse eukaryotic lineages and facilitated assessment of their diversity and relative abundance. Protist diversity differed significantly between habitats and among samples, while richness varied significantly between habitats. Across all samples, 170 genera were identified, of which 52 were shared across all sites. Sabkha exhibited the highest number of exclusive genera (22), nearly three times the number found in any individual rawdha site. The clade Alveolata accounted for 50 % or more of overall genus richness in most samples. Among ciliates, the classes Spirotrichea and Colpodea were the most abundant at the time of sampling. Functional analysis revealed consumers as the dominant trophic group. This study advances our understanding of microbial life in extremely hot environments by uniquely comparing two proximate terrestrial habitats that, despite similar climatic conditions, exhibit distinct edaphic and physicochemical characteristics.
{"title":"Diversity of protists in dryland habitats of Qatar revealed by environmental metabarcoding","authors":"Carla S.R. Huber , Luciano K. Huber , Sara H. Al-Hadidi , Talaat Ahmed , Sakeenah Adenan , Jane Oja , Amjad M. Shraim , Anna Ostapenko Alatalo , Mohammed Alsafran , Leho Tedersoo , Dana A. Abumaali , Laura R.P. Utz , Juha M. Alatalo","doi":"10.1016/j.ejop.2025.126168","DOIUrl":"10.1016/j.ejop.2025.126168","url":null,"abstract":"<div><div>We investigated soil protist communities across five sites representing two characteristic dryland habitats in Qatar: rawdha and sabkha. Altogether, 100 samples were collected during a single field campaign; DNA was subsequently extracted, and the V4 region of the 18S rRNA gene was amplified. We obtained 112,529 high-quality sequences, taxonomically representing 1,524 TSAR (Telonemia, Stramenopila, Alveolata, Rhizaria) amplicon sequence variants. This approach enabled detection of diverse eukaryotic lineages and facilitated assessment of their diversity and relative abundance. Protist diversity differed significantly between habitats and among samples, while richness varied significantly between habitats. Across all samples, 170 genera were identified, of which 52 were shared across all sites. Sabkha exhibited the highest number of exclusive genera (22), nearly three times the number found in any individual rawdha site. The clade Alveolata accounted for 50 % or more of overall genus richness in most samples. Among ciliates, the classes Spirotrichea and Colpodea were the most abundant at the time of sampling. Functional analysis revealed consumers as the dominant trophic group. This study advances our understanding of microbial life in extremely hot environments by uniquely comparing two proximate terrestrial habitats that, despite similar climatic conditions, exhibit distinct edaphic and physicochemical characteristics.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"101 ","pages":"Article 126168"},"PeriodicalIF":1.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145198908","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}
Pub Date : 2025-09-18DOI: 10.1016/j.ejop.2025.126167
Ying Zhang , Fasheng Liang , Chunying Xu , Alan Warren , Lifang Li
Certain ciliate taxa possess a Ca2+-dependent mechanism for ultrafast contraction, in addition to the more common adenosine triphosphate (ATP)-dependent process. In this study, we integrated omics data from 47 ciliate species, focusing on four target ciliate taxa: Vorticellidae, Zoothamniidae, Stentor, and Spirostomum. The spasmin gene, which encodes a key calcium-binding protein, was detected in 17 oligohymenophoreans (13 peritrichs, two peniculians, and two scuticociliatians) and three heterotricheans (one Stentor and two Spirostomum species). Gene family analysis revealed a roughly proportional relationship between genome/transcriptome size and the number of expanded gene families in these four target taxa. Functional enrichment analyses of significantly expanded gene families indicated rapid evolution of genes associated with phosphatase activity, dephosphorylation, signal transduction, metabolism, and transport. These findings provide new insights into the genomic adaptations underlying the unique contractile mechanisms of these ciliates.
{"title":"Comparative genomics reveals insights into the ultrafast Ca2+-dependent cell contraction in ciliates (Eukaryota, SAR, Alveolata)","authors":"Ying Zhang , Fasheng Liang , Chunying Xu , Alan Warren , Lifang Li","doi":"10.1016/j.ejop.2025.126167","DOIUrl":"10.1016/j.ejop.2025.126167","url":null,"abstract":"<div><div>Certain ciliate taxa possess a Ca<sup>2+</sup>-dependent mechanism for ultrafast contraction, in addition to the more common adenosine triphosphate (ATP)-dependent process. In this study, we integrated omics data from 47 ciliate species, focusing on four target ciliate taxa: Vorticellidae, Zoothamniidae, <em>Stentor</em>, and <em>Spirostomum</em>. The spasmin gene, which encodes a key calcium-binding protein, was detected in 17 oligohymenophoreans (13 peritrichs, two peniculians, and two scuticociliatians) and three heterotricheans (one <em>Stentor</em> and two <em>Spirostomum</em> species). Gene family analysis revealed a roughly proportional relationship between genome/transcriptome size and the number of expanded gene families in these four target taxa. Functional enrichment analyses of significantly expanded gene families indicated rapid evolution of genes associated with phosphatase activity, dephosphorylation, signal transduction, metabolism, and transport. These findings provide new insights into the genomic adaptations underlying the unique contractile mechanisms of these ciliates.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"101 ","pages":"Article 126167"},"PeriodicalIF":1.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156923","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}
Pub Date : 2025-09-15DOI: 10.1016/j.ejop.2025.126166
Xiaochen Feng , Wenbao Zhuang , Ran Li , Xiaozhong Hu
Tropidoatractidae, a recently established anaerobic family of metopid ciliates, have not yet been examined from a morphogenetic perspective. In this study, the interphase morphology, morphogenesis during binary fission, and body and certain nuclear changes during conjugation were investigated in a Chinese population of Tropidoatractus levanderi Rotterová et al., 2018 using the protargol impregnation method. The main findings are as follows: (1) the Chinese population closely resembles Czech and Brazilian populations, with the exception of a diplostichomonad type of paroral membrane, a feature previously overlooked; (2) divisional morphogenesis follows the metopid mode, providing further evidence for conserved cell division patterns within metopids, and (3) conjugation is of the total isogamontic type, a rare phenomenon among ciliates. Additionally, 18S rRNA gene sequence comparison and phylogenetic analyses were conducted to complement the morphological observations.
{"title":"Morphogenesis of the anaerobic ciliate Tropidoatractus levanderi (Ciliophora, Armophorea, Metopida), with notes on conjugation and molecular phylogeny","authors":"Xiaochen Feng , Wenbao Zhuang , Ran Li , Xiaozhong Hu","doi":"10.1016/j.ejop.2025.126166","DOIUrl":"10.1016/j.ejop.2025.126166","url":null,"abstract":"<div><div>Tropidoatractidae, a recently established anaerobic family of metopid ciliates, have not yet been examined from a morphogenetic perspective. In this study, the interphase morphology, morphogenesis during binary fission, and body and certain nuclear changes during conjugation were investigated in a Chinese population of <em>Tropidoatractus levanderi</em> Rotterová et al., 2018 using the protargol impregnation method. The main findings are as follows: (1) the Chinese population closely resembles Czech and Brazilian populations, with the exception of a diplostichomonad type of paroral membrane, a feature previously overlooked; (2) divisional morphogenesis follows the metopid mode, providing further evidence for conserved cell division patterns within metopids, and (3) conjugation is of the total isogamontic type, a rare phenomenon among ciliates. Additionally, 18S rRNA gene sequence comparison and phylogenetic analyses were conducted to complement the morphological observations.</div></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"101 ","pages":"Article 126166"},"PeriodicalIF":1.6,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145120382","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}