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Nobutaka Imamura - One of the best experts on this subject based on the ideXlab platform.
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Induction of Maltose Release by Light in the Endosymbiont Chlorella variabilis of Paramecium bursaria.
Protist, 2016Co-Authors: Aika Shibata, Masahiro Kasahara, Fumio Takahashi, Nobutaka ImamuraAbstract:The endosymbiotic green algae of Paramecium bursaria are known to release a photosynthate to the host cells. The endosymbiont Chlorella variabilis F36-ZK isolated in Japan releases maltose under acidic conditions, and such release requires both light and low pH. However, whether photosynthate release is due to light sensing by photoreceptors or is merely a consequence of active photosynthesis is unclear. Herein, we studied the effect of light on maltose release from C. variabilis F36-ZK; we measured maltose release using a combination of 1-phenyl-3-methyl-5-pyrazolone derivative and 14C-tracer methods. Blue (450nm) or red (around 600nm) light was most effective to stimulate maltose release. This suggests that the photosynthetic pathway probably participates in maltose release, because the effective wavelength corresponds to the absorption spectrum of chlorophyll. Furthermore, maltose release was slightly affected by addition of a photosynthetic inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, but was abolished by another inhibitor of photosynthesis, 2,5-dibromo-6-isopropyl-3-methyl-1,4-benzoquinone, suggesting that electron flow through photosystem I may be more involved in maltose release. Interestingly, starving F36-ZK cells cultured under prolonged dark conditions did not release maltose but retained their photosynthetic capacity. Our results thus show that maltose release is regulated by light and cellular conditions in endosymbiotic Chlorella.
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Identifi cation of an Algal Carbon Fixation-Enhancing Factor Extracted from Paramecium bursaria
Zeitschrift fur Naturforschung. C Journal of biosciences, 2011Co-Authors: Yutaka Kato, Nobutaka ImamuraAbstract:The green ciliate Paramecium bursaria contains several hundred symbiotic Chlorella species. We previously reported that symbiotic algal carbon fixation is enhanced by P. bursaria extracts and that the enhancing factor is a heat-stable, low-molecular-weight, water-soluble compound. To identify the factor, further experiments were carried out. The enhancing activity remained even when organic compounds in the extract were completely combusted at 700 degrees C, suggesting that the factor is an inorganic substance. Measurement of the major cations, K+, Ca2+, and Mg2+, by an electrode and titration of the extract resulted in concentrations of 0.90 mM, 0.55 mM, and 0.21 mM, respectively. To evaluate the effect of these cations, a mixture of the cations at the measured concentrations was prepared, and symbiotic algal carbon fixation was measured in the solution. The results demonstrated that the fixation was enhanced to the same extent as with the P. bursaria extract, and thus this mixture of K+, Ca2+, and Mg2+ was concluded to be the carbon fixation-enhancing factor. There was no effect of the cation mixture on free-living C. vulgaris. Comparison of the cation concentrations of nonsymbiotic and symbiotic Paramecium extracts revealed that the concentrations of K+ and Mg2+ in nonsymbiotic Paramecium extracts were too low to enhance symbiotic algal carbon fixation, suggesting that symbiotic P. bursaria provide suitable cation conditions for photosynthesis to its symbiotic Chlorella.
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Isolation and characterization of a virus (CvV-BW1) that infects symbiotic algae of Paramecium bursaria in Lake Biwa, Japan.
Virology journal, 2010Co-Authors: Ryo Hoshina, Yutaka Kato, Mayumi Shimizu, Yoichi Makino, Yoshihiro Haruyama, Shin-ichiro Ueda, Masahiro Kasahara, Bun-ichiro Ono, Nobutaka ImamuraAbstract:We performed an environmental study of viruses infecting the symbiotic single-celled algae of Paramecium bursaria (Paramecium bursaria Chlorella virus, PBCV) in Lake Biwa, the largest lake in Japan. The viruses detected were all Chlorella variabilis virus (CvV = NC64A virus). One of them, designated CvV-BW1, was subjected to further characterization. CvV-BW1 formed small plaques and had a linear DNA genome of 370 kb, as judged by pulsed-field gel electrophoresis. Restriction analysis indicated that CvV-BW1 DNA belongs to group H, one of the most resistant groups among CvV DNAs. Based on a phylogenetic tree constructed using the dnapol gene, CvV was classified into two clades, A and B. CvV-BW1 belonged to clade B, in contrast to all previously identified virus strains of group H that belonged to clade A. We conclude that CvV-BW1 composes a distinct species within C. variabilis virus.
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Origins of Algal Symbionts of Paramecium bursaria
Endosymbionts in Paramecium, 2009Co-Authors: Ryo Hoshina, Nobutaka ImamuraAbstract:The green Paramecium, Paramecium bursaria, has evolved a mutualistic relationship with green algae that has fascinated microbiologists for over a century. Classical approaches to determining the identities of these algae have indicated that the symbionts are close relatives of the genus Chlorella, in which two differentiable algal groups, the “American” (NC64A as the representative strain) and the “European” (Pbi), have been recognized. The identities of these algal partners were finally revealed using molecular phylogenetic and genetic structural analyses. Consequently, both the “American” and the “European” algae are thought to belong to Chlorella sensu stricto; however, each is equivalent to a species distinct from other known Chlorella spp. The majority of P. bursaria symbionts are assigned to either the “American” or the “European” group, but in a few exceptional cases there exist Paramecium associated with C. vulgaris, with Coccomyxa sp., and the double-symbiont association of Choricystis minor with an unidentified “Chlorella-like” alga. All these symbionts are polyphyletic, even among the three Chlorella spp., suggesting that they have arisen as paramecian symbionts from different origins. The “American” and “European” algae are readily distinguishable from each other and other algae by clearly distinct internal transcribed spacers, or by the presence of intronic insertions into unique positions in ribosomal DNA. These introns are distinctive and connote an ancient situation in which both the “American” and the “European” algae cohabitated in a single ciliate. Given the hosts’ genetic divergence, it allows for the development of an evolutionary scenario for P. bursaria with respect to algal acquisition and switching.
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Effect of calcium ion on uptake of amino acids by symbiotic Chlorella F36-ZK isolated from Japanese Paramecium bursaria
Plant Science, 2008Co-Authors: Yutaka Kato, Nobutaka ImamuraAbstract:Symbiotic Chlorella F36-ZK isolated from Paramecium bursaria F36 lacks nitrate reductase activity and has constitutive amino acid transport systems. Divalent cations generally accelerate amino acid uptake and Ca2+ affects membrane permeability and H+-ATPase activity. However, Ser uptake by F36-ZK was decreased by divalent cations, especially Ca2+, and the cation had no effect on membrane permeability or H+-ATPase activity. Extracellular Ca2+ contributed to inhibit Ser uptake. The cation selectively inhibited uptake of Ser, Ala and Gln, which are transported via the same system, but not Arg. Based on kinetic analysis of Ser transport, inhibition was noncompetitive, i.e., Ca2+ affected only the Vmax of Ser uptake. Calcium ions were found in symbiotic Chlorella cells associated with their host by transmission electron microscopy using an oxalate-pyroantimonate method, suggesting the transfer of Ca2+ during symbiosis. From these results obtained in this paper, we discuss the role of divalent cations on amino acid transport in the Paramecium symbiosis.
Masahiro Fujishima - One of the best experts on this subject based on the ideXlab platform.
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Genome plasticity in Paramecium bursaria revealed by population genomics.
BMC biology, 2020Co-Authors: Yu-hsuan Cheng, Masahiro Fujishima, Chien-fu Jeff Liu, Yu-ting Jhou, Isheng Jason Tsai, Jun-yi LeuAbstract:Background Ciliates are an ancient and diverse eukaryotic group found in various environments. A unique feature of ciliates is their nuclear dimorphism, by which two types of nuclei, the diploid germline micronucleus (MIC) and polyploidy somatic macronucleus (MAC), are present in the same cytoplasm and serve different functions. During each sexual cycle, ciliates develop a new macronucleus in which newly fused genomes are extensively rearranged to generate functional minichromosomes. Interestingly, each ciliate species seems to have its way of processing genomes, providing a diversity of resources for studying genome plasticity and its regulation. Here, we sequenced and analyzed the macronuclear genome of different strains of Paramecium bursaria, a highly divergent species of the genus Paramecium which can stably establish endosymbioses with green algae. Results We assembled a high-quality macronuclear genome of P. bursaria and further refined genome annotation by comparing population genomic data. We identified several species-specific expansions in protein families and gene lineages that are potentially associated with endosymbiosis. Moreover, we observed an intensive chromosome breakage pattern that occurred during or shortly after sexual reproduction and contributed to highly variable gene dosage throughout the genome. However, patterns of copy number variation were highly correlated among genetically divergent strains, suggesting that copy number is adjusted by some regulatory mechanisms or natural selection. Further analysis showed that genes with low copy number variation among populations tended to function in basic cellular pathways, whereas highly variable genes were enriched in environmental response pathways. Conclusions We report programmed DNA rearrangements in the P. bursaria macronuclear genome that allow cells to adjust gene copy number globally according to individual gene functions. Our results suggest that large-scale gene copy number variation may represent an ancient mechanism for cells to adapt to different environments.
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Analysis of amino acid and codon usage in Paramecium bursaria.
FEBS Letters, 2015Co-Authors: Hideo Dohra, Masahiro Fujishima, Haruo SuzukiAbstract:The ciliate Paramecium bursaria harbors the green-alga Chlorella symbionts. We reassembled the P. bursaria transcriptome to minimize falsely fused transcripts, and investigated amino acid and codon usage using the transcriptome data. Surface proteins preferentially use smaller amino acid residues like cysteine. Unusual synonymous codon and amino acid usage in highly expressed genes can reflect a balance between translational selection and other factors. A correlation of gene expression level with synonymous codon or amino acid usage is emphasized in genes down-regulated in symbiont-bearing cells compared to symbiont-free cells. Our results imply that the selection is associated with P. bursaria-Chlorella symbiosis.
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Characteristics of the digestive vacuole membrane of the alga-bearing ciliate Paramecium bursaria.
Protist, 2011Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:Cells of the ciliate Paramecium bursaria harbor symbiotic Chlorella spp. in their cytoplasm. To establish endosymbiosis with alga-free P. bursaria, symbiotic algae must leave the digestive vacuole (DV) to appear in the cytoplasm by budding of the DV membrane. This budding was induced not only by intact algae but also by boiled or fixed algae. However, this budding was not induced when food bacteria or India ink were ingested into the DVs. These results raise the possibility that P. bursaria can recognize sizes of the contents in the DVs. To elucidate this possibility, microbeads with various diameters were mixed with alga-free P. bursaria and traced their fate. Microbeads with 0.20μm diameter did not induce budding of the DVs. Microbeads with 0.80μm diameter produced DVs of 5-10μm diameter at 3min after mixing; then the DVs fragmented and became vacuoles of 2-5μm diameter until 3h after mixing. Each microbead with a diameter larger than 3.00μm induced budding similarly to symbiotic Chlorella. These observations reveal that induction of DV budding depends on the size of the contents in the DVs. Dynasore, a dynamin inhibitor, greatly inhibited DV budding, suggesting that dynamin might be involved in DV budding.
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infection of Paramecium bursaria by symbiotic chlorella species
2009Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:Paramecium bursaria and endosymbiotic Chlorella species retain their ability to grow independently, but can reestablish endosymbiosis by mixing. Infection is induced through the host's digestive vacuoles (DVs). Acidosomal and lysosomal fusions to the DVs begin at 0.5 and 2-3 min after mixing, respectively.
James L. Van Etten - One of the best experts on this subject based on the ideXlab platform.
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Chlorella cells and chlorovirus Paramecium bursaria chlorella virus (PBCV-1).
2016Co-Authors: James L. Van Etten, David D. DuniganAbstract:(A) Paramecium bursaria and its symbiotic chlorella cells. (B) Plaques formed by PBCV-1 on a lawn of Chlorella variabilis. (C) Five-fold averaged cryo-electron micrograph of PBCV-1 reveals a long narrow cylindrical spike structure at one vertex and fibers extending from one unique capsomer per trisymmetron. (D) PBCV-1 attached to the cell wall as viewed by the quick-freeze, deep etch procedure. Note the virions attached to the wall by fibers. (E) Surface view of the PBCV-1 spike structure and fibers. (F) Initial attachment of PBCV-1 to a C. variabilis cell wall. (G) Attachment of PBCV-1 to the algal wall and digestion of the wall at the point of attachment. This occurs within 1–3 minutes postinfection (PI) (H) Virion particles assemble in defined areas in the cytoplasm named virus assembly centers at ~4 hour PI. Note that both DNA containing (dark centers) and empty capsids. (I) A model depicting PBCV-1 assembly into infectious particles including generation of nuclei-derived cisternae decorated with ribosomes (red spheres), which serve as precursors (dark blue) for single bilayer viral membranes (light blue) in the viral assembly centers. (J) Localized lysis of cell plasma membrane and cell wall and release of progeny viruses at ~8 hours PI. This figure is modified with permission: Fig 1A–H and J is modified from reference 2 with permission and Fig I is modified from reference 18 with permission.
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Virus-host interactions: insights from the replication cycle of the large Paramecium bursaria chlorella virus.
Cellular microbiology, 2015Co-Authors: Elad Milrot, James L. Van Etten, James R. Gurnon, Yael Mutsafi, Yael Fridmann-sirkis, Eyal Shimoni, Katya Rechav, Abraham MinskyAbstract:The increasing interest in cytoplasmic factories generated by eukaryotic-infecting viruses stems from the realization that these highly ordered assemblies may contribute fundamental novel insights to the functional significance of order in cellular biology. Here, we report the formation process and structural features of the cytoplasmic factories of the large dsDNA virus Paramecium bursaria chlorella virus 1 (PBCV-1). By combining diverse imaging techniques, including scanning transmission electron microscopy tomography and focused ion beam technologies, we show that the architecture and mode of formation of PBCV-1 factories are significantly different from those generated by their evolutionary relatives Vaccinia and Mimivirus. Specifically, PBCV-1 factories consist of a network of single membrane bilayers acting as capsid templates in the central region, and viral genomes spread throughout the host cytoplasm but excluded from the membrane-containing sites. In sharp contrast, factories generated by Mimivirus have viral genomes in their core, with membrane biogenesis region located at their periphery. Yet, all viral factories appear to share structural features that are essential for their function. In addition, our studies support the notion that PBCV-1 infection, which was recently reported to result in significant pathological outcomes in humans and mice, proceeds through a bacteriophage-like infection pathway.
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Paramecium bursaria Chlorella Virus 1 Encodes a Polyamine Acetyltransferase
The Journal of biological chemistry, 2012Co-Authors: Zachary Charlop-powers, James L. Van Etten, Jean Jakoncic, James R. Gurnon, Ming-ming ZhouAbstract:Paramecium bursaria chlorella virus 1 (PBCV-1), a large DNA virus that infects green algae, encodes a histone H3 lysine 27-specific methyltransferase that functions in global transcriptional silencing of the host. PBCV-1 has another gene a654l that encodes a protein with sequence similarity to the GCN5 family histone acetyltransferases. In this study, we report a 1.5 Å crystal structure of PBCV-1 A654L in a complex with coenzyme A. The structure reveals a unique feature of A654L that precludes its acetylation of histone peptide substrates. We demonstrate that A654L, hence named viral polyamine acetyltransferase (vPAT), acetylates polyamines such as putrescine, spermidine, cadaverine, and homospermidine present in both PBCV-1 and its host through a reaction dependent upon a conserved glutamate 27. Our study suggests that as the first virally encoded polyamine acetyltransferase, vPAT plays a possible key role in the regulation of polyamine catabolism in the host during viral replication.
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Three-dimensional structure and function of the Paramecium bursaria chlorella virus capsid
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Xinzheng Zhang, Ye Xiang, David D. Dunigan, Thomas Klose, Paul R. Chipman, James L. Van Etten, Michael G. RossmannAbstract:A cryoelectron microscopy 8.5 Å resolution map of the 1,900 Å diameter, icosahedral, internally enveloped Paramecium bursaria chlorella virus was used to interpret structures of the virus at initial stages of cell infection. A fivefold averaged map demonstrated that two minor capsid proteins involved in stabilizing the capsid are missing in the vicinity of the unique vertex. Reconstruction of the virus in the presence of host chlorella cell walls established that the spike at the unique vertex initiates binding to the cell wall, which results in the enveloped nucleocapsid moving closer to the cell. This process is concurrent with the release of the internal viral membrane that was linked to the capsid by many copies of a viral membrane protein in the mature infectous virus. Simultaneously, part of the trisymmetrons around the unique vertex disassemble, probably in part because two minor capsid proteins are absent, causing Paramecium bursaria chlorella virus and the cellular contents to merge, possibly as a result of enzyme(s) within the spike assembly. This may be one of only a few recordings of successive stages of a virus while infecting a eukaryotic host in pseudoatomic detail in three dimensions.
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Microarray Analysis of Paramecium bursaria Chlorella Virus 1 Transcription
Journal of virology, 2009Co-Authors: Giane M. Yanai-balser, David D. Dunigan, Garry A. Duncan, James D. Eudy, Dong Wang, Irina V. Agarkova, James L. Van EttenAbstract:Paramecium bursaria chlorella virus 1 (PBCV-1), a member of the family Phycodnaviridae, is a large double-stranded DNA, plaque-forming virus that infects the unicellular green alga Chlorella sp. strain NC64A. The 330-kb PBCV-1 genome is predicted to encode 365 proteins and 11 tRNAs. To monitor global transcription during PBCV-1 replication, a microarray containing 50-mer probes to the PBCV-1 365 protein-encoding genes (CDSs) was constructed. Competitive hybridization experiments were conducted by using cDNAs from poly(A)-containing RNAs obtained from cells at seven time points after virus infection. The results led to the following conclusions: (i) the PBCV-1 replication cycle is temporally programmed and regulated; (ii) 360 (99%) of the arrayed PBCV-1 CDSs were expressed at some time in the virus life cycle in the laboratory; (iii) 227 (62%) of the CDSs were expressed before virus DNA synthesis begins; (iv) these 227 CDSs were grouped into two classes: 127 transcripts disappeared prior to initiation of virus DNA synthesis (considered early), and 100 transcripts were still detected after virus DNA synthesis begins (considered early/late); (v) 133 (36%) of the CDSs were expressed after virus DNA synthesis begins (considered late); and (vi) expression of most late CDSs is inhibited by adding the DNA replication inhibitor, aphidicolin, prior to virus infection. This study provides the first comprehensive evaluation of virus gene expression during the PBCV-1 life cycle.
Yuuki Kodama - One of the best experts on this subject based on the ideXlab platform.
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Autolysis of Chlorella variabilis in Starving Paramecium bursaria Help the Host Cell Survive Against Starvation Stress.
Current microbiology, 2021Co-Authors: Yuuki Kodama, Shoya MiyazakiAbstract:The endosymbiosis between Paramecium bursaria and Chlorella spp. is mutualistic. Symbiotic algae localize beneath the host Paramecium cell cortex compete for their attachment sites with preexisting organelle trichocysts. To examine the relationship between P. bursaria trichocysts and their symbiotic algae, algae-bearing or alga-free P. bursaria were starved for several days and the changes in the number of Chlorella sp. and presence or absence of trichocysts were evaluated. We conducted an indirect immunofluorescence microscopy with an anti-trichocyst monoclonal antibody against P. bursaria cells. Indirect immunofluorescence microscopy demonstrated that under starvation and darkness conditions, the immunofluorescence of trichocysts in alga-free P. bursaria decreased much faster than that in the normal algae-bearing P. bursaria. In the latter case, our observations proposed the possibility that the nutrition obtained from symbiotic algal digestion may promote trichocysts synthesis. This algal digestion mechanism may permit host P. bursaria cells to survive for a longer time under starvation condition. To the best of our knowledge, this may be a new benefit that host P. bursaria gain from harboring symbiotic algae.
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OrbiSIMS Imaging Identifies Molecular Constituents of the Perialgal Vacuole Membrane of Paramecium bursaria with Symbiotic Chlorella variabilis.
Analytical chemistry, 2019Co-Authors: Satoka Aoyagi, Yuuki Kodama, Melissa K. Passarelli, Jean-luc Vorng, Tomoko Kawashima, Keisuke Yoshikiyo, Tatsuyuki Yamamoto, Ian S. GilmoreAbstract:The protist (mostly single-celled organisms), Paramecium bursaria, forms an intracellular symbiotic relationship with the single-celled algae, Chlorella variabilis, where P. bursaria provides nutrients (i.e., Ca2+, Mg2+, and K+), carbon dioxide for photosynthesis and protection from viruses, while C. variabilis provides oxygen, carbon fixation, and nutrients. Key to this successful relationship is the perialgal vacuole (PV) membrane, which surrounds C. variabilis and protects it from digestion by P. bursaria. The membrane is fragile and difficult to analyze using conventional methods therefore very little is known about the molecular composition. We used the OrbiSIMS, a new high-resolution mass spectrometer with subcellular resolution imaging, to study the compartmentalization of endosymbionts and elucidate biomolecular interactions between the host and endosymbiont. Ions from the region of interest, close to C. variabilis, and specific to the target samples containing PVs were found based on the chemical...
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Characteristics of the digestive vacuole membrane of the alga-bearing ciliate Paramecium bursaria.
Protist, 2011Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:Cells of the ciliate Paramecium bursaria harbor symbiotic Chlorella spp. in their cytoplasm. To establish endosymbiosis with alga-free P. bursaria, symbiotic algae must leave the digestive vacuole (DV) to appear in the cytoplasm by budding of the DV membrane. This budding was induced not only by intact algae but also by boiled or fixed algae. However, this budding was not induced when food bacteria or India ink were ingested into the DVs. These results raise the possibility that P. bursaria can recognize sizes of the contents in the DVs. To elucidate this possibility, microbeads with various diameters were mixed with alga-free P. bursaria and traced their fate. Microbeads with 0.20μm diameter did not induce budding of the DVs. Microbeads with 0.80μm diameter produced DVs of 5-10μm diameter at 3min after mixing; then the DVs fragmented and became vacuoles of 2-5μm diameter until 3h after mixing. Each microbead with a diameter larger than 3.00μm induced budding similarly to symbiotic Chlorella. These observations reveal that induction of DV budding depends on the size of the contents in the DVs. Dynasore, a dynamin inhibitor, greatly inhibited DV budding, suggesting that dynamin might be involved in DV budding.
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infection of Paramecium bursaria by symbiotic chlorella species
2009Co-Authors: Yuuki Kodama, Masahiro FujishimaAbstract:Paramecium bursaria and endosymbiotic Chlorella species retain their ability to grow independently, but can reestablish endosymbiosis by mixing. Infection is induced through the host's digestive vacuoles (DVs). Acidosomal and lysosomal fusions to the DVs begin at 0.5 and 2-3 min after mixing, respectively.
Maria Rautian - One of the best experts on this subject based on the ideXlab platform.
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Molecular Investigation of Paramecium bursaria Endosymbiotic Algae: the First Records of Symbiotic Micractinium reisseri from Kamchatka
Folia Biologica, 2020Co-Authors: Patrycja Zagata Leśnicka, Magdalena Greczek-stachura, Sebastian Tarcz, Maria RautianAbstract:Paramecium bursaria is a symbiotic ciliate species which cells contain hundreds of algae enclosed in perialgal vacuoles. The aim of the present study was to identify endosymbiotic algal strains of P. bursaria and to define the geographical distribution of the identified species. We analyzed symbiotic strains of P. bursaria originating from distant geographical locations and housed at the Culture Collection of Ciliates and their Symbionts (CCCS) at St. Petersburg University. Based on the obtained results, we identified these strains as Micractinium reisseri , Chlorella vulgaris, and Chlorella variabilis. We did not confirm the occurrence of a division into American and European groups and we guess that this division is only contractual and corresponds to the amount of introns in the 18S rDNA, and that there is no strong correlation with the geographical location. We have demonstrated that the range of M. reisseri is greater than previously supposed. We identified algae strains originating from Southern Europe (Serbia), Western Asia, and from the Far East (Kamchatka) as M. reisseri. Moreover, we identified two strains originating from Europe as C. variabilis, which also contradicts the predetermes about a division into American and European groups.
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The Evolutionary Relationships between Endosymbiotic Green Algae of Paramecium bursaria Syngens Originating from Different Geographical Locations.
Folia biologica, 2016Co-Authors: Patrycja Zagata, Magdalena Greczek-stachura, Sebastian Tarcz, Maria RautianAbstract:Paramecium bursaria (Ehrenberg 1831), a freshwater ciliate, typically harbors hundreds of green algal symbionts inside the cell. The aim of present study was the molecular identification of newly analyzed P. bursaria symbionts. The second aspect of the present survey was testing a hypothesis whether endosymbionts prefer the specified syngen of the host, and the specified geographical distribution. Ten strains of endosymbionts isolated from strains of P. bursaria originating from different geographical locations were studied. We analyzed for the first time, both the fragment of plastid genome containing 3'rpl36-5' infA genes and a fragment of a nuclear gene encoding large subunit ribosomal RNA (LSU rDNA). The analysis of the LSU rDNA sequences showed the existence of 3 haplotypes and the haplotype diversity of 0.733, and 8 haplotypes for the 3'rpl36-5' infA gene fragment and haplotype diversity of 0.956. The endosymbionts isolated from P. bursaria strains were identified as Chlorella vulgaris, Ch. variabilis and Micractinium conductrix. There was no correlation between the syngen of P. bursaria and the species of endosymbiont.
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Molecular Identification of Paramecium bursaria Syngens and Studies on Geographic Distribution using Mitochondrial Cytochrome C Oxidase Subunit I (COI).
Folia biologica, 2015Co-Authors: Patrycja Zagata, Magdalena Greczek-stachura, Sebastian Tarcz, Maria RautianAbstract:Paramecium bursaria is composed of five syngens that are morphologically indistinguishable but sexually isolated. The aim of the present study was to confirm by molecular methods (analyses of mitochondrial COI) the identification of P. bursaria syngens originating from different geographical locations. Phylograms constructed using both the neighbor-joining and maximum-likelihood methods based on a comparison of 34 sequences of P. bursaria strains and P. multimicronucleatum, P. caudatum and P.calkinsi strains used as outgroups revealed five clusters which correspond to results obtained previously by mating reaction. Our analysis shows the existence of 24 haplotypes for the COI gene sequence in the studied strains. The interspecies haplotype diversity was Hd = 0.967. We confirmed genetic differentiation between strains of P. bursaria and the occurrence of a correlation between geographical distribution and the correspondent syngen.
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Phylogenetic placement of two previously described intranuclear bacteria from the ciliate Paramecium bursaria (Protozoa, Ciliophora): ‘Holospora acuminata’ and ‘Holospora curviuscula’
International Journal of Systematic and Evolutionary Microbiology, 2013Co-Authors: Maria Rautian, Natalia D. Wackerow-kouzovaAbstract:‘Holospora acuminata’ infects micronuclei of Paramecium bursaria (Protozoa, Ciliophora), whereas ‘Holospora curviuscula’ infects the macronucleus in other clones of the same host species. Because these micro-organisms have not been cultivated, their description has been based only on some morphological properties and host and nuclear specificities. One16S rRNA gene sequence of ‘H. curviuscula’ is present in databases. The systematic position of the representative strain of ‘H. curviuscula’, strain MC-3, was determined in this study. Moreover, for the first time, two strains of ‘H. acuminata’, KBN10-1 and AC61-10, were investigated. Phylogenetic analysis indicated that all three strains belonged to the genus Holospora , family Holosporaceae , order Rickettsiales within the Alphaproteobacteria .
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identification of Paramecium bursaria syngens through molecular markers comparative analysis of three loci in the nuclear and mitochondrial dna
Protist, 2012Co-Authors: Magdalena Greczekstachura, Alexey Potekhin, Ewa Przyboś, Maria Rautian, Inna I Skoblo, Sebastian TarczAbstract:This is the first attempt to resolve the phylogenetic relationship between different syngens of Paramecium bursaria and to investigate at a molecular level the intraspecific differentiation of strains originating from very distant geographical locations. Herein we introduce a new collection of five P. bursaria syngens maintained at St Petersburg State University, as the international collection of syngens was lost in the 1960s. To analyze the degree of speciation within Paramecium bursaria, we examined 26 strains belonging to five different syngens from distant and geographically isolated localities using rDNA (ITS1-5.8S-ITS2-5'LSU) fragments, mitochondrial cytochrome c oxidase subunit I (COI), and H4 gene fragments. It was shown that P. bursaria strains of the same syngens cluster together in all three inferred molecular phylogenies. The genetic diversity among the studied P. bursaria strains based on rDNA sequences was rather low. The COI divergence of Paramecium bursaria was also definitely lower than that observed in the Paramecium aurelia complex. The nucleotide sequences of the H4 gene analyzed in the present study indicate the extent of genetic differences between the syngens of Paramecium bursaria. Our study demonstrates the diagnostic value of molecular markers, which are important tools in the identification of Paramecium bursaria syngens.
