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Microorganisms Jan 2023The Gram-negative bacterium is a macronucleus-specific symbiont of the ciliate . It is known that an infection of this bacterium induces high level expressions of the...
A 63-kDa Periplasmic Protein of the Endonuclear Symbiotic Bacterium Secreted to the Outside of the Bacterium during the Early Infection Process Binds Weakly to the Macronuclear DNA of the Host .
The Gram-negative bacterium is a macronucleus-specific symbiont of the ciliate . It is known that an infection of this bacterium induces high level expressions of the host and genes, and the host cell acquires both heat-shock and high salt resistances. In addition, an infectious form of -specific 63-kDa periplasmic protein with a DNA-binding domain in its amino acid sequence is secreted into the host macronucleus after invasion into the macronucleus and remain within the nucleus. These facts suggest that binding of the 63-kDa protein to the host macronuclear DNA causes changes in the host gene expressions and enhances an environmental adaptability of the host cells. This 63-kDa protein was renamed as periplasmic region protein 1 (PRP1) to distinguish it from other proteins with similar molecular weights. To confirm whether PRP1 indeed binds to the host DNA, SDS-DNA PAGE and DNA affinity chromatography with calf thymus DNA and DNA were conducted and confirmed that PRP1 binds weakly to the DNA with a monoclonal antibody raised for the 63-kDa protein.
PubMed: 36677447
DOI: 10.3390/microorganisms11010155 -
Bulletin of Experimental Biology and... May 2020We analyzed cytotoxicity of water-soluble potassium salts of (+)- and (-) usnic acid (UA) for ciliates P. caudatum. The median lethal concentrations for (+)- and (-)...
We analyzed cytotoxicity of water-soluble potassium salts of (+)- and (-) usnic acid (UA) for ciliates P. caudatum. The median lethal concentrations for (+)- and (-) enantiomers did not significantly differ and were 7.5±0.5 and 6.7±0.4, respectively. In a concentration of 8 μM, (+)-UA and (-)-UA salts increased the content of TBA-reactive products, which indicates the formation of oxidative stress under the action of high UA concentrations. In the presence of (+)-UA and (-)-UA salts in a concentration range from 2 to 8 μM, the number of food vacuoles in ciliates decreased, which attested to a decrease in phagocytosis activity. The concentrations of UA enantiomers >0.5 μM affected macronucleus morphology (shape and size). The cytotoxic activity of (+)-UA and (-)-UA salts against P. caudatum did not differ.
Topics: Animals; Benzofurans; Dose-Response Relationship, Drug; Molecular Conformation; Oxidative Stress; Paramecium caudatum; Potassium; Salts; Structure-Activity Relationship; Toxicity Tests
PubMed: 32488777
DOI: 10.1007/s10517-020-04835-4 -
Theoretical Population Biology Jun 2022Cell division is a necessity of life which can be either mitotic or amitotic. While both are fundamental, amitosis is sometimes considered a relic of little importance...
Cell division is a necessity of life which can be either mitotic or amitotic. While both are fundamental, amitosis is sometimes considered a relic of little importance in biology. Nevertheless, eukaryotes often have polyploid cells, including cancer cells, which may divide amitotically. To understand how amitosis ensures the completion of cell division, we turn to the macronuclei of ciliates. The grand scheme governing the proliferation of the macronuclei of ciliate cells, which involves chromosomal replication and amitosis, is currently unknown, which is crucial for developing population genetics model of ciliate populations. Using a novel model that encompasses a wide range of mechanisms together with experimental data of the composition of mating types at different stages derived from a single karyonide of Tetrahymena thermophila, we show that the chromosomal replication of the macronucleus has a strong head-start effect, with only about five copies of chromosomes replicated at a time and persistent reuse of the chromosomes involved in the early replication. Furthermore the fission of a fully grown macronucleus is non-random with regard to chromosome composition, with a strong tendency to push chromosomes and their replications to the same daughter cell.
Topics: Cell Division; Chromosomes; Ciliophora; Macronucleus; Tetrahymena thermophila
PubMed: 35331774
DOI: 10.1016/j.tpb.2022.03.004 -
Genome Research 2022With its nuclear dualism, the ciliate constitutes a unique model to study how host genomes cope with transposable elements (TEs). harbors two germline micronuclei...
With its nuclear dualism, the ciliate constitutes a unique model to study how host genomes cope with transposable elements (TEs). harbors two germline micronuclei (MICs) and a polyploid somatic macronucleus (MAC) that develops from one MIC at each sexual cycle. Throughout evolution, the MIC genome has been continuously colonized by TEs and related sequences that are removed from the somatic genome during MAC development. Whereas TE elimination is generally imprecise, excision of approximately 45,000 TE-derived internal eliminated sequences (IESs) is precise, allowing for functional gene assembly. Programmed DNA elimination is concomitant with genome amplification. It is guided by noncoding RNAs and repressive chromatin marks. A subset of IESs is excised independently of this epigenetic control, raising the question of how IESs are targeted for elimination. To gain insight into the determinants of IES excision, we established the developmental timing of DNA elimination genome-wide by combining fluorescence-assisted nuclear sorting with high-throughput sequencing. Essentially all IESs are excised within only one endoreplication round (32C to 64C), whereas TEs are eliminated at a later stage. We show that DNA elimination proceeds independently of replication. We defined four IES classes according to excision timing. The earliest excised IESs tend to be independent of epigenetic factors, display strong sequence signals at their ends, and originate from the most ancient integration events. We conclude that old IESs have been optimized during evolution for early and accurate excision by acquiring stronger sequence determinants and escaping epigenetic control.
Topics: Paramecium tetraurelia; DNA, Protozoan; RNA, Untranslated; DNA Transposable Elements; Germ Cells
PubMed: 36418061
DOI: 10.1101/gr.277027.122 -
BioRxiv : the Preprint Server For... Jun 2024Ciliates are single-celled microbial eukaryotes that diverged from other eukaryotic lineages over a billion years ago. The extensive evolutionary timespan of ciliate has...
Ciliates are single-celled microbial eukaryotes that diverged from other eukaryotic lineages over a billion years ago. The extensive evolutionary timespan of ciliate has led to enormous genetic and phenotypic changes, contributing significantly to their high level of diversity. Recent analyses based on molecular data have revealed numerous cases of cryptic species complexes in different ciliate lineages, demonstrating the need for a robust approach to delimit species boundaries and elucidate phylogenetic relationships. Heterotrich ciliate species of the genus are abundant in freshwater and brackish environments and are commonly used as biological indicators for assessing water quality. However, some species are difficult to identify due to a lack of distinguishable morphological characteristics, and the existence of cryptic species in this genus remains largely unexplored. Previous phylogenetic studies have focused on only a few loci, namely the ribosomal RNA genes, alpha-tubulin, and mitochondrial CO1. In this study, we obtained single-cell transcriptome of 25 species populations (representing six morphospecies) sampled from South Korea and the USA, and used concatenation- and coalescent-based methods for species tree inference and delimitation. Phylogenomic analysis of 37 populations and 265 protein-coding genes provided a robustious insight into the evolutionary relationships among species and confirmed that species with moniliform and compact macronucleus each form a distinct monophyletic lineage. Furthermore, the multispecies coalescent (MSC) model suggests that there are at least nine cryptic species in the genus, three in , two in , and each. Overall, our fine sampling of closely related populations and wide scRNA-seq allowed us to demonstrate the hidden crypticity of species within the genus , and to resolve and provide much stronger support than hitherto to the phylogeny of this important ciliate genus.
PubMed: 38854132
DOI: 10.1101/2024.05.29.596006 -
Acta Parasitologica Jun 2018Balantioides coli is a ciliated protozoon that inhabits the intestine of pigs, non-human primates and humans. Light microscopy studies have described over 50 species of...
Balantioides coli is a ciliated protozoon that inhabits the intestine of pigs, non-human primates and humans. Light microscopy studies have described over 50 species of the genus Balantioides but their validity is in doubt. Due to the limited information about this genus, this study is aimed to identify morphological characteristics of Balantioides coli isolated using fluorescence microscopy and both scanning (SEM) and transmission electron microscopy (TEM). Trophozoites isolated from the feces of pig and macaque were washed and subjected to centrifugation. These cells were fixed with paraformaldehyde for immunofluorescence. Other aliquots of these trophozoites were fixed with glutaraldehyde, post fixed with osmium tetroxide and processed for SEM and TEM. Immunofluorescence studies revealed microtubules with a longitudinal distribution to the main axis of the parasite and in the constitution of cilia. SEM demonstrated a high concentration of cilia covering the oral apparatus and a poor presence of such structures in cytopyge. TEM revealed in the plasma membrane, several associated structures were observed to delineate the cellular cortex and mucocysts. The cytoskeleton of the oral region was observed in detail and had an organization pattern consisting of microtubules, which formed files and nematodesmal networks. Organelles such as hydrogenosomes like and peroxisomes were observed close to the cortex. Macronuclei were observed, but structures that were consistent with micronuclei were not identified. Ultrastructural morphological analysis of isolates confirms its similarity to Balantioides coli. In this study were identified structures that had not yet been described, such as hydrogenosomes like and cytoskeletal structures.
Topics: Animals; Cell Membrane; Feces; Humans; Intestines; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Microtubules; Organelles; Parasites; Peroxisomes; Primates; Protozoan Infections, Animal; Swine; Trophozoites
PubMed: 29654686
DOI: 10.1515/ap-2018-0033 -
PLoS Genetics Jan 2015The Tetrahymena thermophila DNA replication machinery faces unique demands due to the compartmentalization of two functionally distinct nuclei within a single cytoplasm,...
The Tetrahymena thermophila DNA replication machinery faces unique demands due to the compartmentalization of two functionally distinct nuclei within a single cytoplasm, and complex developmental program. Here we present evidence for programmed changes in ORC and MCM abundance that are not consistent with conventional models for DNA replication. As a starting point, we show that ORC dosage is critical during the vegetative cell cycle and development. A moderate reduction in Orc1p induces genome instability in the diploid micronucleus, aberrant division of the polyploid macronucleus, and failure to generate a robust intra-S phase checkpoint response. In contrast to yeast ORC2 mutants, replication initiation is unaffected; instead, replication forks elongation is perturbed, as Mcm6p levels decline in parallel with Orc1p. Experimentally induced down-regulation of ORC and MCMs also impairs endoreplication and gene amplification, consistent with essential roles during development. Unexpectedly Orc1p and Mcm6p levels fluctuate dramatically in developing wild type conjugants, increasing for early cycles of conventional micronuclear DNA replication and macronuclear anlagen replication (endoreplication phase I, rDNA gene amplification). This increase does not reflect the DNA replication load, as much less DNA is synthesized during this developmental window compared to vegetative S phase. Furthermore, although Orc1p levels transiently increase prior to endoreplication phase II, Orc1p and Mcm6p levels decline when the replication load increases and unconventional DNA replication intermediates are produced. We propose that replication initiation is re-programmed to meet different requirements or challenges during the successive stages of Tetrahymena development.
Topics: Cell Cycle; Cell Division; Cell Nucleus; Chromosomes; DNA Replication; DNA, Ribosomal; Gene Expression Regulation, Developmental; Genomic Instability; Origin Recognition Complex; S Phase; Tetrahymena thermophila
PubMed: 25569357
DOI: 10.1371/journal.pgen.1004875 -
Pakistan Journal of Biological Sciences... Jan 2021<b>Background and Objective:</b> Freshwater fish aquaculture in Indonesia has grown rapidly, especially the aquaculture of catfish (<i>Pangasianodon...
<b>Background and Objective:</b> Freshwater fish aquaculture in Indonesia has grown rapidly, especially the aquaculture of catfish (<i>Pangasianodon hypophthalmus</i>). This species is very good because it is fast-growing and very popular in the market and is important for national food security in many Asian countries. One of the problems faced by freshwater fish aquaculture is ectoparasite <i>Ichthyophthirius multifiliis</i> infection, which often results in significant economic losses to freshwater fish aquaculture. This study aimed to check the effect extract of betel leaf against the ectoparasite, <i>Ichthyophthirius multifiliis</i> in pangasius catfish in an eco-friendly manner. <b>Materials and Methods:</b> A total of 120 fishes with a mean weight of 4.17±0.96 g and a length of 8.5±0.67 cm were examined. Preliminary research was carried out to detect ectoparasites in fish. All fish was infected with ectoparasitic Ich (100%) and were identified as a salt-like granule white spot and a large C-shaped macronucleus. Infected fishes were transferred and equally distributed to the tank (20 L water) which had previously been treated with betel leaf extract for 24 hrs, 3 days, at doses 2.5, 5 and 7.5 g L<sup></sup><sup>1</sup> and control. <b>Results:</b> The results showed that the betel leaf extract solution effect decreased significantly to the number of ectoparasites <i>Ichthyophthirius multifiliis</i>, both in mucus and pangasius catfish and a dose of 7.5 g L<sup></sup><sup>1</sup> was the optimum dose. <b>Conclusion:</b> Betel leaf extract has the potential to control the decrease in the number of ectoparasites, though further phytochemical studies will need to be performed.
Topics: Animals; Aquaculture; Areca; Body Weight; Catfishes; Female; Fish Diseases; Hymenostomatida; Indonesia; Macronucleus; Male; Piperaceae; Plant Extracts; Plant Leaves; Reactive Oxygen Species; Temperature
PubMed: 34486358
DOI: 10.3923/pjbs.2021.905.912 -
International Journal of Molecular... Jun 2023Mismatch repair (MMR) is a conserved mechanism that is primarily responsible for the repair of DNA mismatches during DNA replication. Msh2 forms MutS heterodimer...
Mismatch repair (MMR) is a conserved mechanism that is primarily responsible for the repair of DNA mismatches during DNA replication. Msh2 forms MutS heterodimer complexes that initiate the MMR in eukaryotes. The function of Msh2 is less clear under different chromatin structures. contains a transcriptionally active macronucleus (MAC) and a transcriptionally silent micronucleus (MIC) in the same cytoplasm. Msh2 is localized in the MAC and MIC during vegetative growth. Msh2 is localized in the perinuclear region around the MIC and forms a spindle-like structure as the MIC divides. During the early conjugation stage, Msh2 is localized in the MIC and disappears from the parental MAC. Msh2 is localized in the new MAC and new MIC during the late conjugation stage. Msh2 also forms a spindle-like structure with a meiotic MIC and mitotic gametic nucleus. knockdown inhibits the division of MAC and MIC during vegetative growth and affects cellular proliferation. knockdown mutants are sensitive to cisplatin treatment. knockdown also affects micronuclear meiosis and gametogenesis during sexual development. Furthermore, Msh2 interacts with MMR-dependent and MMR-independent factors. Therefore, Msh2 is necessary for macronuclear stability, as well as micronuclear mitosis and meiosis in .
Topics: Tetrahymena thermophila; MutS Homolog 2 Protein; DNA Mismatch Repair; Cell Nucleus; Macronucleus
PubMed: 37445734
DOI: 10.3390/ijms241310559 -
Biochimica Et Biophysica Acta.... Jun 2022Developmental DNA elimination in Paramecium tetraurelia occurs through a trans-nuclear comparison of the genomes of two distinct types of nuclei: the germline...
Developmental DNA elimination in Paramecium tetraurelia occurs through a trans-nuclear comparison of the genomes of two distinct types of nuclei: the germline micronucleus (MIC) and the somatic macronucleus (MAC). During sexual reproduction, which starts with meiosis of the germline nuclei, MIC-limited sequences including Internal Eliminated Sequences (IESs) and transposons are eliminated from the developing MAC in a process guided by noncoding RNAs (scnRNAs and iesRNAs). However, our current understanding of this mechanism is still very limited. Therefore, studying both genetic and epigenetic aspects of these processes is a crucial step to understand this phenomenon in more detail. Here, we describe the involvement of homologs of classical meiotic proteins, Spo11, Msh4-1, and Msh5 in this phenomenon. Based on our analyses, we propose that proper functioning of Spo11, Msh4-1, and Msh5 during Paramecium sexual reproduction are necessary for genome reorganization and viable progeny. Also, we show that double-strand breaks (DSBs) in DNA induced during meiosis by Spo11 are crucial for proper IESs excision. In summary, our investigations show that early sexual reproduction processes may significantly influence later somatic genome integrity.
Topics: Germ Cells; Macronucleus; Meiosis; Paramecium tetraurelia; RNA, Untranslated
PubMed: 35181406
DOI: 10.1016/j.bbamcr.2022.119239