{"title":"Comparison of mixotrophic and heterotrophic chrysomonads of similar size regarding bacterivory and growth rate","authors":"Tobias Pietsch, Hartmut Arndt","doi":"10.1016/j.ejop.2024.126109","DOIUrl":"10.1016/j.ejop.2024.126109","url":null,"abstract":"<div><p>Small chrysomonads are important bacterivores in aquatic ecosystems with a high molecular diversity compared to low morphological differences observed by light microscopy. The high diversity of these morphologically almost indistinguishable species leads to the question to which extent their functional role in ecosystems differs and how their ecological traits can be defined. The present study investigates the prey size and population growth rate of different chrysomonad species. Eleven phylogenetically well-defined strains representing seven strains of heterotrophic and four strains of mixotrophic chrysomonads were compared. All investigated strains belonged to the same functional group of bacterivorous flagellates, feeding on the same bacteria size range, while population growth rates of chrysomonads depended on nutritional strategy and species-specific differences. We observed a high individual variability of growth rates within a population. Our results point to the necessity to consider not only differences in ecological traits among species but also among specimens within a population.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126109"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000592/pdfft?md5=7c67f02916851a93cc54e576f31261d8&pid=1-s2.0-S0932473924000592-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141853626","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}
Eun-Hye Do , Hye-In Kwon , Jeong Hyeon Yeo , Pablo Quintela-Alonso , Jae-Ho Jung
{"title":"Morphology and molecular phylogeny of Euplotes baugilensis n. sp. (Ciliophora, Spirotrichea), with an illustrated key to Euplotes species with reduced cirri","authors":"Eun-Hye Do , Hye-In Kwon , Jeong Hyeon Yeo , Pablo Quintela-Alonso , Jae-Ho Jung","doi":"10.1016/j.ejop.2024.126110","DOIUrl":"10.1016/j.ejop.2024.126110","url":null,"abstract":"<div><p><em>Euplotes baugilensis</em> n. sp. was discovered in a temporary puddle that formed after rainfall on a mountain footpath near Gangneung-Wonju National University in Gangneung, South Korea. After isolation, a pure culture was established, and the new species was examined using live observation, silver-impregnation (protargol and ‘wet’ silver nitrate), scanning electron microscopy, and the analysis of the 18S rRNA gene sequence. Morphologically, <em>E. baugilensis</em> n. sp. is characterized by small body size (on average 49 × 31 µm in vivo), 9 ordinary fronto-ventral cirri (cirrotype-9) with one reduced cirrus V/2 (composed of four non-ciliated basal bodies), 5 transverse cirri, 7 or 8 dorsolateral kineties, 6 dorsal prominent ridges, and a dargyrome (silverline system) of double type. In this study, we have used a combination of morphological and molecular techniques to characterize <em>E. baugilensis</em> n. sp. and determine its phylogenetic position within the genus <em>Euplotes</em>. Molecular analysis using 18S rRNA gene sequences indicated that <em>E. baugilensis</em> n. sp. is most closely related to <em>E. curdsi</em> (with a sequence identity of 96.8 %).</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126110"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141838439","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 , Fengru Li , Jeongmin Shin , Jang-Seu Ki
{"title":"Molecular characterization of a catalase gene in the freshwater green alga Closterium ehrenbergii and its putative function against abiotic stresses","authors":"Hui Wang , Peiling Wu , Fengru Li , Jeongmin Shin , Jang-Seu Ki","doi":"10.1016/j.ejop.2024.126111","DOIUrl":"10.1016/j.ejop.2024.126111","url":null,"abstract":"<div><p>Catalases (CATs) are ubiquitous antioxidant enzymes that prevent cellular oxidative damage through the decomposition of H<sub>2</sub>O<sub>2</sub>. However, there is relatively little information on CAT in the worldwide-distributed freshwater green alga <em>Closterium ehrenbergii</em>. Here, we cloned the full-length catalase cDNA from <em>C</em>. <em>ehrenbergii</em> (<em>CeCAT</em>) and characterized its structural features and expressional responses against aquatic contaminants. The open reading frame of <em>CeCAT</em> was determined to be 1476 bp, encoding 491 amino acids with a theoretical molecular mass of 56.1 kDa. The CeCAT protein belongs to the NADPH-binding CAT family and might be located in the cytosol. BLAST and phylogenetic results showed that CeCAT had a high identity with CAT proteins from other microalgae and the water lily <em>Nymphaea colorata</em> (Streptophyta). The transcriptional levels of <em>CeCAT</em> were significantly upregulated by the metal copper and herbicide atrazine, but little affected by other tested metals (Ni and Cr) and endocrine-disrupting chemicals (polychlorinated biphenyl, PCB). The maximum expression was registered under 0.1 mg/L CuCl<sub>2</sub> and 0.2 mg/L CuSO<sub>4</sub> exposures. In addition, excess copper considerably increased production of reactive oxygen species in the cells. These results suggest that CeCAT may function to defend against oxidative stress in green algae and can respond specifically to different kinds of metals and herbicides.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126111"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141964274","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":"Ciliate diversity and growth rates in experimental recirculating aquaculture and aquaponics systems using microscopy","authors":"Stefanos Moschos , Konstantinos Ar. Kormas , Hera Karayanni","doi":"10.1016/j.ejop.2024.126113","DOIUrl":"10.1016/j.ejop.2024.126113","url":null,"abstract":"<div><p>The function of recirculating aquaculture systems (RAS) relies on microbial communities, which convert toxic, fish-excreted ammonia into substances that can provide nutrients to plants as in the case of aquaponics systems. In the present study, heterotrophic protist communities of experimental sea water RAS and freshwater aquaponics systems were investigated using microscopy to characterize their diversity, natural abundance, and potential growth rates. Heterotrophic protist abundance was low (732 ± 21 to 5451 ± 118 ciliates L<sup>−1</sup> and 58 ± 8 to 147 ± 18 nanoflagellates mL<sup>−1</sup> in the aquaponics system and 78 ± 28 to 203 ± 48 ciliates L<sup>−1</sup> in the RAS), which is in line with values typically reported for rivers. In the aquaponics system, ciliates grew faster in the fish rearing tanks (1.9 ± 0.01 to 1.21 ± 0.03 d<sup>−1</sup> compared to 0.54 ± 0.03 to 0.79 ± 0.05 d<sup>−1</sup> in the other compartments), while heterotrophic nanoflagellates grew slower in drain tanks downstream of the hydroponics compartment (0.5 ± 0.3 to 1.37 ± 0.05 d<sup>−1</sup> and 4.09 ± 0.11 d<sup>−1</sup> to 6.03 ± 0.34 d<sup>−1</sup>in the other compartments). Results indicated distinct niches and reduced microeukaryotic diversity at the end of the system’s operation cycle.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126113"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142083916","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":"Quantitative analysis of trichocysts in Paramecium bursaria following artificial removal and infection with the symbiotic Chlorella variabilis","authors":"Hikaru Morita , Yuuki Kodama","doi":"10.1016/j.ejop.2024.126115","DOIUrl":"10.1016/j.ejop.2024.126115","url":null,"abstract":"<div><p>The ciliate <em>Paramecium bursaria</em> possesses cell organelles called trichocysts that have defensive functions. <em>Paramecium bursaria</em> is capable of symbiosis with <em>Chlorella variabilis</em>, and the symbiotic algae are situated in close proximity to the trichocysts. To clarify the relationship between trichocysts in <em>P. bursaria</em> and the presence or absence of the intracellular symbiotic <em>C</em>. <em>variabilis</em>, this study compared the regeneration capacity of trichocysts in alga-free and algae-bearing <em>P. bursaria</em>. In addition, trichocyst protein abundance was measured when alga-free <em>P. bursaria</em> specimens were artificially infected with <em>Chlorella</em>. After completely removing trichocysts from <em>P. bursaria</em> cells by treatment with lysozyme and observing them after 24 h, the percentage of regenerating trichocysts in the entire cell was significantly higher in alga-free cells than that in algae-bearing cells. We also developed a simple method for the isolation of high-purity trichocysts to quantify trichocyst protein amounts. There was a significant difference in the trichocyst protein abundance of <em>P. bursaria</em> before and one week after mixing with <em>Chlorella</em> (i.e., after the establishment of symbiosis with algae). This study shows the importance of trichocysts in alga-free <em>P. bursaria</em> as well as their competition with symbiotic <em>C. variabilis</em> for attachment sites during the algal infection process.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126115"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098175","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":"Protist diversity and co-occurrence patterns obtained by metabarcoding of terricolous lichens, coastal cliffs and a microbial mat in the Atacama Desert, northern Chile","authors":"Eduardo Acosta, Frank Nitsche, Hartmut Arndt","doi":"10.1016/j.ejop.2024.126108","DOIUrl":"10.1016/j.ejop.2024.126108","url":null,"abstract":"<div><p>Protists can endure challenging environments sustaining key ecosystem processes of the microbial food webs even under aridic or hypersaline conditions. We studied the diversity of protists at different latitudes of the Atacama Desert by massive sequencing of the hypervariable region V9 of the 18S rRNA gene from soils and microbial mats collected in the Andes. The main protist groups in soils detected in active stage through cDNA were cercozoans, ciliates, and kinetoplastids, while the diversity of protists was higher including diatoms and amoebae in the microbial mat detected solely through DNA. Co-occurrence networks from soils indicated similar assemblages dominated by amplicon sequence variants (ASVs) identified as <em>Rhogostoma</em>, <em>Euplotes</em>, and <em>Neobodo</em>. Microbial mat networks, on the other hand, were structured by ASVs classified as raphid-pennate diatoms and amoebae from the genera <em>Hartmannella</em> and <em>Vannella</em>, mostly negatively correlated to flagellates and microalgae. Additionally, our phylogenetic inferences of ASVs classified as <em>Euplotes</em>, <em>Neobodo</em>, and <em>Rhogostoma</em> were supported by sequence data of strains isolated during this study. Our results represent the first snapshot of the diversity patterns of culturable and unculturable protists and putative keystone taxa detected at remote habitats from the Atacama Desert.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126108"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000580/pdfft?md5=30f646a13589443cbaafd0a4351779e8&pid=1-s2.0-S0932473924000580-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141850328","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":"Description of Conchophthirus sinanodontae n. sp. (Ciliophora: Scuticociliatia), a new endocommensal ciliate of the freshwater mussel Sinanodonta woodiana from Korea","authors":"Kyu-Seok Chae , Jae-Ho Jung , Gi-Sik Min","doi":"10.1016/j.ejop.2024.126112","DOIUrl":"10.1016/j.ejop.2024.126112","url":null,"abstract":"<div><p>The morphology and molecular phylogeny of a new ciliate, <em>Conchophthirus sinanodontae</em> n. sp., which was discovered in the freshwater mussel <em>Sinanodonta woodiana</em> (Lea, 1834) from the Chilsancheon River, Buyeo-gun, South Korea, were investigated. The new species was characterized and could be distinguished from congeners by a combination of characters including the ovate body outline, four to six oral polykinetids deeply embedded in the upper wall of the buccal cavity, six to ten vestibular kineties, 34–49 ventral and 36–53 dorsal somatic kineties. The genetic differences among <em>C. sinanodontae</em> n. sp. and other congeners with available 18S rDNA sequences further support its distinctness. Moreover, the phylogenetic analyses based on the 18S rDNA sequences show that the new species clusters with other congeners, corroborating the monophyly of the genus <em>Conchophthirus</em>. The <em>Conchophthirus</em> clade nests within the cluster of <em>Dexiotricha</em> spp., <em>Loxocephalus luridus</em>, and <em>Haptophrya</em> spp.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126112"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142145467","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":"An investigation into the morphological variation and ecological-environmental range of Cyphoderia compressa: A case study of Scottish material","authors":"Jim Buckman , Vladimir Krivtsov , Alex J. Poulton","doi":"10.1016/j.ejop.2024.126106","DOIUrl":"10.1016/j.ejop.2024.126106","url":null,"abstract":"<div><p><em>Cyphoderia compressa</em> has only been described from supralittoral environments, as a psammobiont, with salinities from 1.33 to 36.00 ‰. Other <em>Cyphoderia</em> species such as those in the <em>C. ampulla</em> species complex are more ecologically and environmentally widespread, occurring as free-living individuals within water bodies or in association with vegetation, and over a wider salinity range, including freshwater. We postulate that <em>C. compressa</em> may not be as restricted in terms of its environmental or ecological distribution. To this end, we examined a variety of water and sediment samples from Scottish localities, ranging from supralittoral to inland freshwater environments. The Scottish material occurs as a psammobiont within supralittoral beach sands and is newly recorded within sands from freshwater to brackish stream sections and along the margin of the freshwater Loch Lomond. It is also recorded from freshwater to brackish settings as part of the stream and pond water biota, associated biofilm and vegetative material. Test morphology is more variable than previously appreciated, including those with a papillate fundus, and many that are not as laterally compressed as typified by the species. Differences in plate morphology and size were also noted, as well as a novel arcuate cross-cutting ridged cement structure, that is restricted to <em>C. compressa</em>.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126106"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000567/pdfft?md5=d160aa9ca30248b59d8fef74548955ed&pid=1-s2.0-S0932473924000567-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141694833","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}
Leon Berchtenbreiter , Abdullah Emir Mumcu , Antonia Stephanie Rackevei , J. Mark Cock , Hiroshi Kawai , Matthias Wolf
{"title":"18S and ITS2 rRNA gene sequence-structure phylogeny of the Phaeophyceae (SAR, Stramenopiles) with special reference to Laminariales","authors":"Leon Berchtenbreiter , Abdullah Emir Mumcu , Antonia Stephanie Rackevei , J. Mark Cock , Hiroshi Kawai , Matthias Wolf","doi":"10.1016/j.ejop.2024.126107","DOIUrl":"10.1016/j.ejop.2024.126107","url":null,"abstract":"<div><p>The phylogeny of brown algae (Phaeophyceae) has undergone extensive changes in the recent past due to regular new scientific insights. We used nuclear 18S rDNA with an extensive dataset, aiming to increase the accuracy and robustness of the reconstructed phylogenetic trees using a simultaneous sequence-structure approach. Individual secondary structures were generated for all 18S rDNA sequences. The sequence-structure information was encoded and used for an automated simultaneous sequence-structure alignment. Neighbor-joining and profile neighbor-joining trees were calculated based on 186 phaeophycean sequence-structure pairs. Additionally, sequence-structure neighbor-joining, maximum parsimony and maximum likelihood trees were reconstructed on a representative subset. Using a similar approach, ITS2 rDNA sequence-structure information was used to reconstruct a neighbor-joining tree including 604 sequence-structure pairs of the Laminariales. Our study results are in significant agreement with previous single marker 18S and ITS2 rDNA analyses. Moreover, the 18S results are in wide agreement with recent multi-marker analyses. The bootstrap support was significantly higher for our sequence-structure analysis in comparison to sequence-only analyses in this study and the available literature. This study supports the simultaneous inclusion of sequence-structure data at least for 18S to obtain more accurate and robust phylogenetic trees compared to sequence-only analyses.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126107"},"PeriodicalIF":1.9,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0932473924000579/pdfft?md5=47ff8a30b8663718d21e5038900254e1&pid=1-s2.0-S0932473924000579-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638548","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}
Wen-Long Song , Min Li , Zi-Qi Wang , Shuang-Lin Chen
{"title":"Taxonomy and phylogeny of three species in Perichaena sensu lato (Myxomycetes = Myxogastria) from China","authors":"Wen-Long Song , Min Li , Zi-Qi Wang , Shuang-Lin Chen","doi":"10.1016/j.ejop.2024.126105","DOIUrl":"10.1016/j.ejop.2024.126105","url":null,"abstract":"<div><p>After <em>Gulielmina</em> was erected and <em>Ophiotheca</em> was resurrected based on some species originally included in <em>Perichaena</em> (Trichiaceae, Trichiales, Myxomyxetes), some specimens from the Herbarium of Fungi of Nanjing Normal University previously identified as <em>Perichaena</em> species were reexamined from morphological and two-gene (nuclear 18S rDNA and elongation factor-1 alpha) phylogenetic perspectives. In this study, two new myxomycete species, <em>Gulielmina subreticulospora</em> and <em>Ophiotheca dictyospora</em>, are described. <em>Gulielmina subreticulospora</em> shows the following character combination: branched plasmodiocarps, single peridium with circular protrusions in the inner surface, capillitium (2.4–)2.8–3.0(–3.4) μm in diameter, spores (7.4–)8.0–8.5(–9.0) μm in diameter and sub-reticulated. <em>Ophiotheca dictyospora</em> shows the following character combination: sessile sporocarps to short plasmodiocarps, single peridium with a densely irregular network and protrusions in the inner surface, capillitium (2.7–)3.5–5.0(–7.1) μm in diameter, uneven, decorated with spines of uneven size, spores (7.7–)8.2–8.6(–9.4) μm in diameter including obviously complete cristate reticulation with serrated edges, with deep and clear grids. Both new taxa were compared with related species and their genetic isolation was statistically tested. Moreover, a comprehensive morphological description and a detailed figure plate are provided for <em>Perichaena verrucifera</em>, and its phylogenetic position is determined.</p></div>","PeriodicalId":12042,"journal":{"name":"European journal of protistology","volume":"95 ","pages":"Article 126105"},"PeriodicalIF":1.9,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141394200","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}