Protist最新文献

{"title":"Genomic architecture constrains macromolecular allocation in dinoflagellates","authors":"Olga Carnicer ,&nbsp;Ying-Yu Hu ,&nbsp;Vinitha Ebenezer ,&nbsp;Andrew J. Irwin ,&nbsp;Zoe V. Finkel","doi":"10.1016/j.protis.2023.125992","DOIUrl":"10.1016/j.protis.2023.125992","url":null,"abstract":"<div><p><span>Dinoflagellate<span><span><span> genomes have a unique architecture that may constrain their physiological and biochemical responsiveness to environmental stressors. Here we quantified how nitrogen (N) starvation influenced macromolecular allocation and C:N:P of three photosynthetic marine dinoflagellates, representing different taxonomic classes and genome sizes. Dinoflagellates respond to nitrogen starvation by decreasing cellular nitrogen, protein and </span>RNA<span> content, but unlike many other eukaryotic phytoplankton examined RNA:protein is invariant. Additionally, 2 of the 3 species exhibit increases in cellular phosphorus and very little change in cellular carbon with N-starvation. As a consequence, N starvation induces moderate increases in C:N, but extreme decreases in N:P and C:P, relative to diatoms. Dinoflagellate </span></span>DNA content<span> relative to total C, N and P is much higher than similar sized diatoms, but similar to very small photosynthetic picoeukaryotes such as </span></span></span><span><em>Ostreococcus</em></span>. In aggregate these results indicate the accumulation of phosphate stores may be an important strategy employed by dinoflagellates to meet P requirements associated with the maintenance and replication of their large genomes.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 6","pages":"Article 125992"},"PeriodicalIF":2.5,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41145851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Taxonomy and molecular phylogeny of pleurostomatid ciliates from China with a description of two new species","authors":"Gongaote Zhang ,&nbsp;Yuan Li ,&nbsp;Ruitao Gong ,&nbsp;Yu Qiao ,&nbsp;Saleh A. Al-Farraj ,&nbsp;Hongbo Pan ,&nbsp;Zhe Wang ,&nbsp;Hunter N. Hines","doi":"10.1016/j.protis.2023.125975","DOIUrl":"10.1016/j.protis.2023.125975","url":null,"abstract":"<div><p><span>Ciliates in the order Pleurostomatida are found free-living in many habitats including within biofilms, but some (e.g. </span><em>Pseudoamphileptus</em><span> spp.) are ectocommensal on various hosts. Due to issues involving overall undersampling, the exact diversity and molecular phylogeny of this group remain largely underexplored. To combat this deficiency, detailed investigations were undertaken in northern China. As a result of these studies, we provide the morphological descriptions of two new species. </span><em>Pseudoamphileptus apomacrostoma</em><span> sp. nov., a new ectocommensal species, is characterized by the broadly oval cell shape, numerous scattered contractile vacuoles<span>, and unique densely bounded extrusomes; </span></span><em>Amphileptus qingdaoensis</em> sp. nov., a marine form, is characterized by possessing oblong extrusomes with a conical anterior end, a single contractile vacuole and 5–7 left and 18–23 right kineties. In addition, a new population of <em>Amphileptus orientalis</em><span> Zhang et al., 2022, a freshwater representative, was documented and an improved diagnosis is provided. The phylogenetic analyses based on the SSU rDNA sequences imply that the genus </span><em>Pseudoamphileptus</em> is monophyletic whereas the genus <em>Amphileptus</em> is paraphyletic. The new molecular sequences presented here further support the establishment of two new species.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 4","pages":"Article 125975"},"PeriodicalIF":2.5,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9918384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protozoa in the remarkable wall charts of Leuckart and Nitsche's Zoologische Wandtaflen","authors":"John Richard Dolan","doi":"10.1016/j.protis.2023.125974","DOIUrl":"10.1016/j.protis.2023.125974","url":null,"abstract":"","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 4","pages":"Article 125974"},"PeriodicalIF":2.5,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9902755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Taxonomy of a New Parasitic Euglenid, Euglenaformis parasitica sp. nov. (Euglenales, Euglenaceae) in Ostracods and Rhabdocoels","authors":"Koichiro Kato ,&nbsp;Kensuke Yahata ,&nbsp;Takeshi Nakayama","doi":"10.1016/j.protis.2023.125967","DOIUrl":"10.1016/j.protis.2023.125967","url":null,"abstract":"<div><p><span>Parasitic euglenids<span> have rarely been studied. We found parasitic euglenids in two species of ostracods (</span></span><em>Cyprinotus cassidula</em>, <em>Dolerocypris sinensis</em><span>) and two species of rhabdocoels (</span><em>Mesostoma lingua</em>, <em>Microdalyellia armigera</em><span><span>) in a rice field. These parasites grew and proliferated inside the host body. These parasites had pellicle strips, one emergent flagellum, and a red stigma, but no chloroplasts, and showed euglenoid movement. Inside the living host, they did not have emergent flagella and moved only by euglenoid movement, but when the host died or the parasites were isolated from the host, they extended their flagella and switched to swimming movement. We conclude that the parasites found in the four hosts that we examined are of the same species, considering the morphological characteristics and identities in the nSSU and nLSU rDNA sequences of those parasites. Molecular </span>phylogenetic analysis showed that the parasite formed a clade with the free-living photoautotrophic species of </span><em>Euglenaformis</em>, with moderate statistical support. Therefore, the parasite is a secondary osmotroph derived from a photoautotrophic ancestor. Based on the results of morphological observation and molecular phylogenetic analysis, we propose a new species of parasitic euglenid, <em>Euglenaformis parasitica</em> sp. nov.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 4","pages":"Article 125967"},"PeriodicalIF":2.5,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9918365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diverse eukaryotic phytoplankton from around the Marquesas Islands documented by combined microscopy and molecular techniques","authors":"Jana Veselá-Strejcová ,&nbsp;Eleonora Scalco ,&nbsp;Adriana Zingone ,&nbsp;Sébastien Colin ,&nbsp;Luigi Caputi ,&nbsp;Diana Sarno ,&nbsp;Jana Nebesářová ,&nbsp;Chris Bowler ,&nbsp;Julius Lukeš","doi":"10.1016/j.protis.2023.125965","DOIUrl":"10.1016/j.protis.2023.125965","url":null,"abstract":"<div><p><span><span>Oceanic phytoplankton serve as a base for the food webs within the largest planetary ecosystem. Despite this, surprisingly little is known about species composition, function and ecology of phytoplankton communities, especially for vast areas of the open ocean. In this study we focus on the marine phytoplankton </span>microflora from the vicinity of the Marquesas Islands in the Southern Pacific Ocean collected during the </span><em>Tara</em><span><span> Oceans expedition. Multiple samples from four sites and two depths were studied in detail using light microscopy, scanning </span>electron microscopy<span>, and automated confocal laser scanning microscopy<span>. In total 289 taxa were identified, with Dinophyceae<span> and Bacillariophyceae contributing 60% and 32% of taxa, respectively, to phytoplankton community composition. Notwithstanding, a large number of cells could not be assigned to any known species. Coccolithophores and other flagellates together contributed less than 8% to the species list. Observed cell densities were generally low, but at sites of high autotrophic biomass, diatoms reached the highest cell densities (1.26 × 10</span></span></span></span>⁴ cells L⁻¹). Overall, 18S rRNA metabarcode-based community compositions matched microscopy-based estimates, particularly for the main diatom taxa, indicating consistency and complementarity between different methods, while the wide range of microscopy-based methods permitted several unknown and poorly studied taxa to be revealed and identified.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 4","pages":"Article 125965"},"PeriodicalIF":2.5,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9914614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Mayorella Species Isolated from the Mariana Trench Area (Pacific Ocean)","authors":"Xiaoli Lei ,&nbsp;Xiaojuan Chen ,&nbsp;Jianming Chen ,&nbsp;Chen Liang","doi":"10.1016/j.protis.2023.125958","DOIUrl":"10.1016/j.protis.2023.125958","url":null,"abstract":"<div><p>In this paper, we describe a new naked amoeba species, <em>Mayorella marianaensis</em> sp. n., order Dermamoebida, isolated from the bottom of the Pacific Ocean (&gt;3,000 m depth) in the vicinity of the Mariana Trench, based on morphological and molecular data. The newly discovered species was identified based on morphological and molecular data. This is the first time that a <em>Mayorella</em> species was discovered in the deep sea (&gt;1,000 m). <em>Mayorella marianaensis</em> is an irregularly rectangular naked amoeba (30–120 × 11–60 µm), with a narrow frontal hyaline area. Four to 15 conical sub-pseudopodia, and three kinds of floating forms are identified. Trophozoites have a thick cell coat consisting of two distinct layers. The small subunit ribosomal RNA gene phylogeny showed that <em>M</em>. <em>marianaensis</em> is classified into Dermamoebida, and is a sister clade to other <em>Mayorella</em> species whose sequences are available. BLAST analysis revealed that <em>M</em>. <em>marianaensis</em> is most similar to <em>Coronamoeba villafranca</em> and <em>Mayorella</em> sp. JJP-2003, with sequence identities of 92.43% and 88.30%, respectively.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 3","pages":"Article 125958"},"PeriodicalIF":2.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10005854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro Evaluation the Efficacy of Some New Plant Extracts and Biocides on the Viability of Acanthamoeba castellanii","authors":"Anas Abdullah Hamad","doi":"10.1016/j.protis.2023.125966","DOIUrl":"10.1016/j.protis.2023.125966","url":null,"abstract":"<div><p><span>The purpose of this study was to assess the efficacy of certain plant extracts and to compare them with current biocides on the viability of </span><span><em>Acanthamoeba</em><em> castellanii</em></span> cysts and trophozoites in vitro. Amoebicidal and cysticidal assays were performed against both trophozoites and cysts of <span><em>Acanthamoeba castellanii</em></span><span> (ATCC 50370). Ten plant extracts were evaluated alongside the current agents included polyhexamethylene biguanide (PHMB), octenidine and chlorhexidine digluconate. </span><em>A. castellanii</em> (ATCC 50370) was treated to serial two-fold dilutions of the test compounds and extracts in microtitre plate wells to investigate the effect on trophozoites and cysts of <em>A. castellanii</em><span> (ATCC 50370). Furthermore, the toxicity of each of the test compounds and extracts were assessed towards a mammalian cell line. Minimum trophozoite inhibitory concentration (MTIC), minimum trophozoite amoebicidal concentration (MTAC), and minimum cysticidal concentration (MCC) were used to establish </span><em>A. castellanii</em> (ATCC 50370) in vitro sensitivity. The findings of this research revealed that the biguanides PHMB, chlorhexidine, and octenidine all had excellent effectiveness against trophozoites and cysts of <em>A. castellanii</em> (ATCC 50370)<em>.</em> The plant extracts testing results showed that, great activity against trophozoites and cysts of<!--> <em>A. castellanii</em> (ATCC 50370) at lower concentrations. This is the first study to demonstrate that the Proskia plant extract had the lowest MCC value, which was 3.9 µg/mL. The time kill experiment confirmed this finding, as this extract reduced cysts of <em>A. castellanii</em> (ATCC 50370) by more than 3-log at 6 hour and by 4-log after 24 hour. The anti-amoebic efficacy of new plant extracts on the viability of <em>A. castellanii</em> (ATCC 50370) cysts and trophozoites was comparable to existing biocide treatments and was not toxic when tested on a mammalian cell line. This could be a promising novel <em>Acanthamoeba</em> treatment by using the tested plant extracts as a monotherapy against trophozoites and cysts.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 3","pages":"Article 125966"},"PeriodicalIF":2.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10007918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microalga–bacteria Community with High Level Carbon Dioxide Acclimation and Nitrogen-fixing Ability","authors":"Haruki Iida,&nbsp;Nobuhiro Aburai,&nbsp;Katsuhiko Fujii","doi":"10.1016/j.protis.2023.125957","DOIUrl":"10.1016/j.protis.2023.125957","url":null,"abstract":"<div><p>Microalgal conversion of high-level CO₂ in industrial flue gas to value-added products is attractive technology for mitigating global warming. However, reduction of microalgal production costs for medium ingredients, particularly nitrogen salts, is essential. The use of atmospheric nitrogen as a nitrogen source for microalgal cultivation will dramatically reduce its production costs. We attempted to enrich a microalga–bacteria community, which fixes both CO₂ and atmospheric nitrogen under high level CO₂. By cultivating biofilm recovered from the surface of cobbles in a riverbank, a microalgal flora which grows in a nitrogen salts-free medium under 10% CO₂ was enriched, and the coccoid microalgal strain MP5 was isolated from it. Phylogenetic analysis revealed that the strain MP5 belongs to the genus <em>Coelastrella</em>, and the closest known species was <em>C. terrestris</em>. With PCR–DGGE analysis, it was found that the enriched microalgal community includes bacteria, some of which are suggested diazotrophs. The addition of bactericides in culture medium inhibited MP5 growth, even though the strain MP5 is eukaryotic. Growth of bacteria-free MP5 was stimulated by addition of <em>Agrobacterium</em> sp. isolates in nitrogen salts-free medium, suggesting that MP5 and the bacteria have responsibility for photosynthetic carbon fixation and nitrogen fixation, respectively.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 3","pages":"Article 125957"},"PeriodicalIF":2.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9647679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sterol Composition of the Peridinin-Containing Dinoflagellate Gertia stigmatica, a Member of the Kareniaceae without a Canonical Haptophyte-Derived Plastid","authors":"Jeffrey D. Leblond,&nbsp;Kyra Sabir,&nbsp;Henry L. Whittemore","doi":"10.1016/j.protis.2023.125939","DOIUrl":"10.1016/j.protis.2023.125939","url":null,"abstract":"<div><p><em>Gertia stigmatica</em><span> is a recently described member of the Kareniaceae with a peridinin-containing plastid rather than the aberrant, haptophyte-derived, tertiary plastid found in canonical Kareniaceae genera such as </span><span><em>Karenia</em></span>, <span><em>Karlodinium</em></span>, and <em>Takayama</em>. <em>G. stigmatica</em> provides a unique opportunity to compare biochemical traits, such as sterol composition, between these two fundamentally different types of Kareniaceae. To this point, canonical members of the Kareniaceae have been observed to typically produce a set of 4α-methyl-substituted, Δ⁸⁽¹⁴⁾-nuclear-unsaturated major sterols, such as (24<em>R</em>)-4α-methyl-5α-ergosta-8(14),22-dien-3β-ol (gymnodinosterol) and 27-<em>nor</em>-(24<em>R</em><span>)-4α-methyl-5α-ergosta-8(14),22-dien-3β-ol (brevesterol), which are very uncommon throughout other members of the class Dinophyceae. Our objective was to compare the sterols of </span><em>G. stigmatica</em> to canonical Kareniaceae to elucidate whether these same distinctive sterols are found, with our hypothesis being that they would because <em>G. stigmatica</em> is indeed a member of the Kareniaceae. Contrary to our hypothesis, <em>G. stigmatica</em> lacks gymnodinosterol and brevesterol, with its sterols instead dominated by 4-desmethyl sterols, such as cholesterol, 24-methylcholesta-5,22E-dien-3β-ol, and the unusual tri-unsaturated sterols ergosta-5,8(14),22E-trien-3β-ol and cholesta-5,8(14),22E-trien-3β-ol. No sterols were found to possess a 4α-methyl substituent or a single Δ⁸⁽¹⁴⁾ nuclear unsaturation. Thus, <em>G. stigmatica</em>'s sterol composition as a member of the Kareniaceae is atypical.</p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 2","pages":"Article 125939"},"PeriodicalIF":2.5,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9627119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterisation and Cultivation of New Lineages of Colponemids, a Critical Assemblage for Inferring Alveolate Evolution","authors":"Andrea S. Gigeroff ,&nbsp;Yana Eglit,&nbsp;Alastair G.B. Simpson","doi":"10.1016/j.protis.2023.125949","DOIUrl":"10.1016/j.protis.2023.125949","url":null,"abstract":"<div><p><span><span><span>There are several alveolate groups outside the well-studied trio – </span>ciliates<span>, dinoflagellates<span>, and apicomplexans – that are crucial for understanding the evolution of this major taxon. One such assemblage is the “colponemids”, which are eukaryotrophic biflagellates, usually with a ventral groove associated with the posterior flagellum. Previous </span></span></span>phylogenetic<span> studies show colponemids forming up to three distinct deep branches within alveolates (e.g. sister groups to Myzozoa or all other alveolates). We have developed dieukaryotic (predator–prey) cultures of four colponemid isolates. One represents the first stable culture of the halophile </span></span><em>Palustrimonas</em> (feeding on <em>Pharyngomonas</em><span>), while SSU rDNA phylogenies show the other isolates as two distinct new lineages. </span><em>Neocolponema saponarium</em><span> gen. et sp. nov. is a swimming alkaliphile<span> with a large groove, which feeds on a kinetoplastid. </span></span><em>Loeffela hirca</em> gen. et sp. nov. is halophilic, has a subtle groove, usually moves along surfaces, and feeds on <em>Pharyngomonas</em> and <em>Percolomonas</em><span>. Prey capture<span> in both new genera<span> is raptorial<span>, involves a specialized structure/region to the right of the proximal posterior flagellum, and presumed extrusomes. The relationships amongst Myzozoa, ciliates, and the (now) five described colponemid clades are unresolved, signaling that colponemid diversity represents both a challenge and important resource for tracing deep alveolate evolution.</span></span></span></span></p></div>","PeriodicalId":20781,"journal":{"name":"Protist","volume":"174 2","pages":"Article 125949"},"PeriodicalIF":2.5,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9636744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}