Hemiselmis andersenii strain:CCMP644
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PROVIDER: PRJNA29201 | ENA |
REPOSITORIES: ENA
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Project description:Hemiselmis andersenii nucleomorph genome
| PRJNA27817 | ENA
Project description:Hemiselmis andersenii nucleomorph genome sequencing
| PRJNA27761 | ENA
Project description:Hemiselmis cryptochromatica CCMP 1181 Standard Draft genome sequencing
| PRJNA1341144 | ENA
Project description:Hemiselmis tepida CCMP 443 Resequencing
| PRJNA1326704 | ENA
Project description:Hemiselmis rufescens CCMP 440 Resequencing
| PRJNA1326668 | ENA
Project description:BACKGROUND: Cryptophytes are an enigmatic group of unicellular eukaryotes with plastids derived by secondary (i.e., eukaryote-eukaryote) endosymbiosis. Cryptophytes are unusual in that they possess four genomes-a host cell-derived nuclear and mitochondrial genome and an endosymbiont-derived plastid and 'nucleomorph' genome. The evolutionary origins of the host and endosymbiont components of cryptophyte algae are at present poorly understood. Thus far, a single complete mitochondrial genome sequence has been determined for the cryptophyte Rhodomonas salina. Here, the second complete mitochondrial genome of the cryptophyte alga Hemiselmis andersenii CCMP644 is presented. RESULTS: The H. andersenii mtDNA is 60,553 bp in size and encodes 30 structural RNAs and 36 protein-coding genes, all located on the same strand. A prominent feature of the genome is the presence of a approximately 20 Kbp long intergenic region comprised of numerous tandem and dispersed repeat units of between 22-336 bp. Adjacent to these repeats are 27 copies of palindromic sequences predicted to form stable DNA stem-loop structures. One such stem-loop is located near a GC-rich and GC-poor region and may have a regulatory function in replication or transcription. The H. andersenii mtDNA shares a number of features in common with the genome of the cryptophyte Rhodomonas salina, including general architecture, gene content, and the presence of a large repeat region. However, the H. andersenii mtDNA is devoid of inverted repeats and introns, which are present in R. salina. Comparative analyses of the suite of tRNAs encoded in the two genomes reveal that the H. andersenii mtDNA has lost or converted its original trnK(uuu) gene and possesses a trnS-derived 'trnK(uuu)', which appears unable to produce a functional tRNA. Mitochondrial protein coding gene phylogenies strongly support a variety of previously established eukaryotic groups, but fail to resolve the relationships among higher-order eukaryotic lineages. CONCLUSION: Comparison of the H. andersenii and R. salina mitochondrial genomes reveals a number of cryptophyte-specific genomic features, most notably the presence of a large repeat-rich intergenic region. However, unlike R. salina, the H. andersenii mtDNA does not possess introns and lacks a Lys-tRNA, which is presumably imported from the cytosol.
| S-EPMC2397417 | biostudies-literature
Project description:Cryptophyte algae have a unique phycobiliprotein light-harvesting antenna that fills a spectral gap in chlorophyll absorption from photosystems. However, it is unclear how the antenna transfers energy efficiently to these photosystems. We show that the cryptophyte Hemiselmis andersenii expresses an energetically complex antenna comprising three distinct spectrotypes of phycobiliprotein, each composed of two αβ protomers but with different quaternary structures arising from a diverse α subunit family. We report crystal structures of the major phycobiliprotein from each spectrotype. Two-thirds of the antenna consists of open quaternary form phycobiliproteins acting as primary photon acceptors. These are supplemented by a newly discovered open-braced form (~15%), where an insertion in the α subunit produces ~10 nm absorbance red-shift. The final components (~15%) are closed forms with a long wavelength spectral feature due to substitution of a single chromophore. This chromophore is present on only one β subunit where asymmetry is dictated by the corresponding α subunit. This chromophore creates spectral overlap with chlorophyll, thus bridging the energetic gap between the phycobiliprotein antenna and the photosystems. We propose that the macromolecular organization of the cryptophyte antenna consists of bulk open and open-braced forms that transfer excitations to photosystems via this bridging closed form phycobiliprotein.
| S-EPMC10643455 | biostudies-literature
Project description:Cystoisospora suis, a member of the apicomplexan order Coccidia and causative agent of neonatal porcine coccidiosis, poses a challenge to pig production due to the emergence of reduced efficacy of toltrazuril, the only EU-approved treatment. To address the critical gaps in understanding toltrazuril resistance and possibilities of early diagnostics, our study investigated the genetic basis of resistance through whole-genome DNA sequencing and transcriptome analysis of two C. suis strains, the toltrazuril-susceptible Wien-I and the resistant Holland-I. Additionally, we studied the mitochondrial genome and analysed mitochondrial gene expression in both strains. Our results show that genes encoding proteins involved in host-cell invasion displayed variable expression patterns and genetic mutations, suggesting adaptive changes in invasion mechanisms. Moreover, substantial fluctuations in the expression of genes linked to retrotransposons, accompanied by genetic alterations, were observed, highlighting their potential involvement in genomic rearrangements. Finally, our mitochondrial genome analyses revealed important insights into its genetic organization and conservation. Notably, the marked downregulation of CoI, CoIII and Cytb mRNA levels in the resistant strain Holland-I upon toltrazuril exposure highlights the dynamic response of mitochondrial genes to toltrazuril. These mitochondrial adaptations appear to be closely linked to the parasite drug resistance mechanism, potentially facilitating its survival under pharmacological stress. These findings enhance our knowledge of drug resistance mechanisms in Coccidia and highlight the need for novel management strategies, leading to the development of targeted treatments and controls.
2025-02-14 | GSE268275 | GEO
Project description:ChIP-seq data characterizing the occupancy of TFAM over the mitochondrial and nuclear genomes in HeLa cells. Characterization of mitochondrial and nuclear genome-wide TFAM binding in HeLa cells
2013-09-21 | E-GEOD-48176 | biostudies-arrayexpress
Project description:Nucleomorphs are the remnant nuclei of algal endosymbionts that took up residence inside a nonphotosynthetic eukaryotic host. The nucleomorphs of cryptophytes and chlorarachniophytes are derived from red and green algal endosymbionts, respectively, and represent a stunning example of convergent evolution: their genomes have independently been reduced and compacted to <1 megabase pairs (Mbp) in size (the smallest nuclear genomes known) and to a similar three-chromosome architecture. The molecular processes underlying genome reduction and compaction in eukaryotes are largely unknown, as is the impact of reduction/compaction on protein structure and function. Here, we present the complete 0.572-Mbp nucleomorph genome of the cryptophyte Hemiselmis andersenii and show that it is completely devoid of spliceosomal introns and genes for splicing RNAs-a case of complete intron loss in a nuclear genome. Comparison of H. andersenii proteins to those encoded in the slightly smaller (0.551-Mbp) nucleomorph genome of another cryptophyte, Guillardia theta, and to their homologs in the unicellular red alga Cyanidioschyzon merolae reveal that (i) cryptophyte nucleomorph genomes encode proteins that are significantly smaller than those in their free-living algal ancestors, and (ii) the smaller, more compact G. theta nucleomorph genome encodes significantly smaller proteins than that of H. andersenii. These results indicate that genome compaction can eliminate both coding and noncoding DNA and, consequently, drive the evolution of protein structure and function. Nucleomorph proteins have the potential to reveal the minimal functional units required for basic eukaryotic cellular processes.
| S-EPMC2148396 | biostudies-literature